Note: Descriptions are shown in the official language in which they were submitted.
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CLEANING SHEETS COMPRISING A POLYMERIC ADDITIVE TO IMPROVE
PARTICULATE PICK-UP AND MINIMIZE RESIDUE LEFT ON SURFACES AND
CLEANING IMPLEMENTS FOR USE WITH CLEANING SHEETS
TECHNICAL FIELD
The present invention relates to cleaning implements and cleaning sheets
particularly
suitable for removal and entrapment of dust, lint, hair, sand, food crumbs,
grass and the like.
BACKGROUND OF THE INVENTION
The use of nonwoven sheets for dry dust-type cleaning are known in the art.
Such sheets
typically utilize a composite of fibers where the fibers are bonded via
adhesive, entangling or
other forces. See, for example, U.S. Patent No. 3,629,047 and U.S. Patent
5,144,729. To provide
a durable wiping sheet, reinforcement means have been combined with the staple
fibers in the
form of a continuous filament or network structure. See, for example, U.S.
Patent No. 4,808,467,
U.S. Patent 3,494,821 and U.S. Patent No. 4,144,370. Also, to provide a
product capable of
withstanding the rigors of the wiping process, prior nonwoven sheets have
employed strongly
bonded fibers via one or more of the forces mentioned above. Such a cleaning
sheet is described
in European patent applications EP 774,229 A2 and EP 777,997 A2, which utilize
continuous
filaments bonded to a base sheet via heat-seal lines. While durable materials
can be obtained, such
strong bonding may adversely impact the materials' ability to pick up and
retain particulate dirt.
In an effort to address this concern, an additive consisting of mineral oil
has been applied to such
cleaning sheets at relatively high levels. However, a mineral oil additive,
when applied to such
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cleaning sheets at such high levels, tends to leave an unappealing residue on
surfaces that are
wiped with such cleaning sheets which is unacceptable to consumers.
U.S. Patent No. 5,599,550 issued February 4, 1997 to Kohiruss et al. describes
a
biodegradable wax-impregnated dust cloth. However, the dust cloth disclosed by
Kohlruss utilizes
natural fibers and relatively high levels of wax, both of which contribute to
eliminating the dust-
attracting properties of the cloth.
A variety of tack cloths have been disclosed that comprise pressure sensitive
adhesive
and/or tackifier materials. See, e.g., U.S. Patent No. 5,198,292; U.S. Patent
No. 3,658,578; U.S.
Patent No. 3,208,093. However, these tack cloths typically contain relatively
high levels of
additives and/or undesirable additives for incorporation in cleaning sheets,
especially cleaning
sheets used to clean household surfaces, wherein consumers find aspects of the
cleaning sheet
such as hand feel and glide as important to consumer acceptance.
It has thus been a desire of those skilled in the art to develop a cleaning
sheet that has an
ability to effectively pick up and retain particulate dirt, while maintaining
the electrostatic
properties and glide of the cleaning sheet, and minimizing the amount of
residue left on the
surface being wiped with such cleaning sheet.
In addition, while cleaning implements, such as floor mops, which utilize
removable
cleaning sheets are known, there is a need to provide cleaning implements
which better utilize the
cleaning sheet by maximizing the surface of the sheet which collects and/or
traps particulate dirt.
Still further, there is a need for cleaning implements which can effectively
cooperate with
cleaning sheets which pick up and retain particulate dirt, maintain the
electrostatic properties and
glide of the cleaning sheet, and minimize the amount of residue left on the
surface being wiped.
SUMMARY OF THE INVENTION
The present invention relates to cleaning sheets for removing and retaining
particulate
material such as dust, lint, hair, sand, food crumbs, grass and the like from
surfaces, while
minimizing the amount of residue left on the surface after being wiped with
the cleaning sheet.
The present cleaning sheets comprise an additive, whereby the type and level
of additive is
selected such that the ability of the cleaning sheet to pick-up and retain
particulate material is
improved, while the residue left on the surface is minimized. The additives
contained on cleaning
sheets can leave varying amounts of residue on the surface being cleaned,
depending upon the
type of additive A number of additive materials can be suitable for
incorporation into the cleaning
sheets of the present invention. Preferred additives of the present invention
that are particularly
useful with the present cleaning sheets are polymeric additives, especially
those with specific
adhesive characteristics such as specific Tack Values, Adhesive Work Values,
Cohesion/Adhesion Ratios, Stringiness Values, Tg Values, and/or molecular
weight. Other
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additive materials that are optional in the present invention include, but are
not limited to waxes,
oils, powders, and mixtures thereof. The additive material is selected in
order to improve the pick-
up of fine particulate matter such as dust, lint, and hair, and especially
larger particulate matter
typically found on household floors and surfaces such as crumbs, dirt, sand,
hair, crushed food,
grass clippings and mulch. In addition, the type and amount of the additive
material is carefully
selected in order to improve particulate pick-up of the cleaning sheet, while
maintaining the
ability of the cleaning sheet to easily glide across the surface being
cleaned. If the cleaning sheet
is too tacky as a result of the additives incorporated therein, the cleaning
sheet will not easily
glide across the surface, leading to consumer dissatisfaction.
The present invention further relates to mop head for a cleaning implement
having a
resilient bottom surface, a portion of which preferably has a substantially
smooth curved profile
or crown which engages the removable cleaning sheet.
The present invention further relates to a floor mop having a mop head
dimensioned to
receive cleaning sheets which are sized for both hand dusting and dusting with
a floor mop.
The present invention further relates to a kit is comprising a mop head, or a
cleaning sheet
which when used with a mop head, provides a bottom surface having one of the
previously
described profiles for producing a repeated rocking or pivoting motion of the
mop head during
use. Still further, the kit preferably includes a coupling, having at least
two, and, more preferably,
at least three, bores which are angled relative to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and
distinctly
claiming the invention, it is believed that the present invention will be
better understood from the
following description taken in conjunction with the accompanying drawings in
which:
Fig. 1 is a perspective view of a floor mop suitable for use with the present
invention;
Fig. 2 is a perspective view of a floor mop suitable for use with the present
invention,
wherein a cleaning sheet is shown disposed about the mop head;
Fig. 3 is a cross sectional side view of the floor mop of Fig. 1, taken along
line 3-3
thereof, wherein the upper portion of the universal joint and the entire
handle have been omitted
for clarity;
Fig. 4 is an enlarged cross-sectional side view of the elastic pad of the
floor mop of Fig.
3;
Fig. 5 is an enlarged partial cross-sectional side view of a preferred elastic
pad made in
accordance with the present invention, wherein the contact surface is a
tangency point;
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Fig. 6 is an enlarged partial cross-sectional side view of another preferred
elastic pad
made in accordance with the present invention, wherein the contact surface is
substantially
straight;
Fig. 7 is an enlarged partial cross-sectional side view of the elastic pad of
Fig. 5, wherein
a cleaning sheet is disposed adjacent the pad;
Fig. 8 is an enlarged partial cross-sectional side view of the elastic pad of
Fig. 6, wherein
a cleaning sheet is disposed adjacent the pad;
Fig. 9 is a cross-sectional side view of an elastic pad made in accordance
with the present
invention, wherein the bottom surface of the elastic pad has a pyramidal
surface texture;
Fig. 10 is an enlarged partial cross-sectional side view of the surface
texture of the elastic
pad of Fig. 9;
Fig. 11 is an enlarged partial cross-sectional side view of the preferred
elastic pad of Fig.
5, wherein the radius of curvature is illustrated;
Fig. 12 is a cross-sectional side view of another preferred elastic pad for
the floor mop of
Fig. 1 made in accordance with the present invention, wherein the bottom
surface of the elastic
pad has a stepped profile;
Fig. 13 is a partial cross-sectional side view of an elastic pad, cleaning
sheet, and stepped
insert made in accordance with the present invention;
Fig. 14 is a partial cross-sectional side view of an elastic pad and cleaning
sheet, wherein
the cleaning sheet has high loft at the leading and trailing edges of the
elastic pad;
Fig. 15 is a perspective view of a coupling suitable for use with the floor
mop of Fig. 1;
Fig 16 is a cross-sectional side view of the coupling of Fig. 15, taken along
line 16-16
thereof;
Fig. 17 is a perspective view of the floor mop of Fig. 1 with the coupling of
Fig. 16
inserted therein, wherein the mop head is in a first orientation relative to
the handle;
Fig. 18 is a perspective view of the floor mop of Fig. 17, wherein the mop
head is in a
second orientation relative to the handle;
Fig. 19 is a perspective view showing a first embodiment of a heat-bonded
cleaning sheet
of the present invention;
Fig. 20 is a sectional view taken along a line III-I1I in Fig. 19;
Fig. 21 is a perspective view showing a second embodiment of the cleaning
sheet being
different from the embodiment shown by Fig. 19;
Fig. 22 is a perspective view showing a third embodiment of the cleaning sheet
being also
different from the embodiment shown by Fig. 19;
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Fig. 23 is a digital photograph of a perspective view showing a fourth
embodiment of the
cleaning sheet which comprises brushy filaments, also being different from the
embodiment
shown by Fig. 19;
Fig. 24 is a diagram illustrating a process for making a cleaning sheet as
shown in Fig.
23;
Fig. 25 is a photograph (12x magnification) of a hydroentangled cleaning sheet
of the
present invention, which depicts a high basis weight continuous region and a
plurality of low
basis weight discrete regions;
Fig. 26 is a plan view of the hydroentangled cleaning sheet depicted in Fig.
25, to
facilitate discussion of the basis weight differences of the sheet;
Fig. 27 is a schematic diagram of a texture analyzer used in the Texture
Analyzer Test
Method described in Section V.A. herein;
Fig. 28 is a graph of force (g) versus distance (mm) generated from the
Texture Analyzer
Test Method described in Section V.A. herein; and
Fig. 29 is a plan view of a cleaning sheet of the present invention having a
center zone
and two side zones comprising a polymeric additive.
DETAILED DESCRIPTION OF THE INVENTION
1. Definitions
As used herein, the term "comprising" means that the various components,
ingredients, or
steps, can be conjointly employed in practicing the present invention.
Accordingly, the term
"comprising" encompasses the more restrictive terms "consisting essentially
of' and "consisting
of'.
As used herein, the term "hydroentanglement" means generally a process for
making a
material wherein a layer of loose fibrous material (e.g., polyester) is
supported on an apertured
patterning member and is subjected to water pressure differentials
sufficiently great to cause the
individual fibers to entangle mechanically to provide a fabric. The apertured
patterning member
may be formed, e.g., from a woven screen, a perforated metal plate, and the
like.
As used herein, the term "Z-dimension" refers to the dimension orthogonal to
the length
and width of the cleaning sheet of the present invention, or a component
thereof. The Z-
dimension usually corresponds to the thickness of the sheet.
As used herein, the term "X-Y dimension" refers to the plane orthogonal to the
thickness
of the cleaning sheet, or a component thereof. The X and Y dimensions usually
correspond to the
length and width, respectively, of the sheet or a sheet component.
As used herein, the term "layer" refers to a member or component of a cleaning
sheet
whose primary dimension is X-Y, i.e., along its length and width. It should be
understood that
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the term "layer" is not necessarily limited to single layers or sheets of
material. Thus the layer
can comprise laminates or combinations of several sheets or webs of the
requisite type of
materials. Accordingly, the term "layer" includes the terms "layers" and
"layered."
For purposes of the present invention, an "upper" layer of a cleaning sheet is
a layer that
is relatively further away from the surface that is to be cleaned (i.e., in
the implement context,
relatively closer to the implement handle during use). The term "lower" layer
conversely means a
layer of a cleaning sheet that is relatively closer to the surface that is to
be cleaned (i.e., in the
implement context, relatively further away from the implement handle during
use).
As used herein, the term "total aggregate basis weight" refers to the average
basis weight
of an entire cleaning sheet, when viewed as a whole sheet.
All percentages, ratios and proportions used herein are by weight unless
otherwise
specified. All references cited are incorporated herein by reference unless
otherwise stated.
Reference will now be made in detail to the present preferred embodiments of
the
cleaning implement of the present invention, examples of which are illustrated
in the
accompanying drawings wherein like numerals indicate the same elements
throughout the views
and wherein elements having the same last two digits (e.g., 22 and 122)
represent similar
elements.
II. Cleaning Implements
As discussed more fully hereafter, one aspect of the present invention is, in
its most
preferred form, directed to a mop for use with a removable cleaning sheet
which is attached to a
mop head having a resilient bottom surface, a portion of which preferably has
a substantially
smooth curved profile or crown which engages the removable cleaning sheet.
While the present
invention is discussed herein with respect to a floor mop for purposes of
simplicity and clarity, it
will be understood that the present invention can be used with other types of
mops and cleaning
implements which have a cleaning sheet releasably secured there about.
Referring to Figs. 1 and 2, a particularly preferred floor mop 20 made in
accordance with
the present invention is illustrated. The floor mop 20 comprises a mop head 22
having a leading
edge 24 and a trailing edge 26 (Fig. 3). As used herein, the term "leading
edge" is intended to
refer to the furthest edge of the mop head 22 which leads the mop head 22 when
it is moved in a
forward direction away from its user. Likewise, the term "trailing edge" is
intended to refer to the
furthest edge of the mop head 22 which trails the mop head 22 when it is moved
in a forward
direction away from its user. For most floor mops, the leading edge 24 and the
trailing edge 26
are substantially parallel to the longitudinal axis 28 of the mop head 22, as
shown in Fig. 1,
wherein the longitudinal axis 28 is the axis along the length of the mop head
22.
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A pivotable joint, such as the universal joint 30, interconnects the handle 32
of the mop
20 with the mop head 22. The universal joint 30 comprises two rotational axes
which allow the
handle 32 to pivot in directions 36 and 38. The handle 32 is interconnected,
preferably threadedly
interconnected, with the universal joint 30 at the connection 40. The handle
32 can be provided
as a unitary structure or can comprise more than one section, preferably three
sections 34, 36, and
38 which are interconnected, preferably threadedly interconnected, with each
other so that the
floor mop 20 can be shipped within a carton of convenient size and later
assembled for use. The
handle section 38 can be provided with an elastic and resilient portion
suitable for gripping by a
user of the floor mop 20. The mop head 22 also comprises a plurality of
attachment structures 42.
The attachment structures 42 are configured to receive and retain a cleaning
sheet 44 about the
mop head 22, as shown in Fig. 2, during use. The attachment structures 42 are
preferably
disposed at the corners of the mop head 22, although these locations can be
varied depending
upon the size and shape of the mop head 22.
The floor mop 20 is preferably used in combination with the disposable
cleaning sheet 44 which is releasably attached to the mop head 22 using the
slitted attachment
structures 42. The cleaning sheet can be provided in the form of a woven or
non-woven fabric, as
discussed more fully hereafter.
Referring to Figs. 3 and 4 and in accordance with one aspect of the present
invention, a
particularly preferred mop head 22 includes a base 46 to which the universal
joint 30 is attached
and an elastic pad 48 which is attached, preferably adhesively attached, to
the base 46, wherein
the leading edge 24 and the trailing edge 26 of the mop head 22 are formed as
part of the elastic
pad 48. The bottom surface 50 of the elastic pad 48 engages at least a
portion, and, more
preferably, a substantial portion of the cleaning sheet 44 during use, as
shown in Fig. 4.
Surprisingly, it has been found that an elastic pad 48 having a contact
surface 52 with a width 53
which is less than about 50 nun provides improved sheet cleaning performance
and sheet usage
efficiency (e.g., increased usage of the bottom surface of the sheet). Not
intending to be bound by
any theory, it is believed that the width 53 of the contact surface 52
provides a mop which can
repeatedly "rock" or "pivot" or "rotate" about the contact surface 52 during
any single continuous
forward and/or backward sweeping motion of the mop 20, thereby providing
increased dust and
particulate collection across a larger percentage of the surface area of the
cleaning sheet 44 as the
bottom surface of the sheet repeatedly engages and disengages the hard surface
to be cleaned due
to the rocking motion. It is also believed that the pivoting about the contact
surface 52 is further
aided by a gap 54 at the leading and/or trailing edges 24 and 26 of the mop
head 22 as well as the
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cross-sectional shape of the profile of the bottom surface, as discussed more
fully hereafter. As
used herein, the phrase "contact surface" is intended to refer the portion of
the cross-sectional
profile of the bottom surface of either the mop head 22 or the cleaning sheet
44 contacted by a
straight line 56 tangent to the apex of that bottom surface, wherein the
straight line 56 is
substantially perpendicular to the transverse axis 58 of the mop head 22.
While it is preferred that
the cross-sectional profile of the bottom surface of the mop head or the
cleaning sheet is the same
along the entire longitudinal axis of the mop head or the cleaning sheet, any
cross-sectional
profile can be used herein to determine the contact surface. It will be
understood that all
measurements herein are based upon the theoretical or true shape and size of
the mop head and/or
cleaning sheet prior to deformation during use. As used herein, the term
"apex" is intended to
refer to that portion of the bottom surface of either the mop head 22 or the
cleaning sheet 44
which is furthest from the top surface 60 of the mop head 22.
For clarity and by way of example with reference to Figs. 5 and 6, the contact
surface 152
of the mop head is the theoretical point of tangency 162 for the curved bottom
surface 150 of the
mop elastic pad 148 with the straight line 156, the straight line 156 being
substantially
perpendicular to the transverse axis 158 of the mop head. Likewise, the
contact surface 252 of the
elastic pad 248 of Fig. 6 is the substantially straight portion of the profile
of the elastic pad 248
which contacts the straight line 256, the straight line 256 being
substantially perpendicular to the
transverse axis 258 of the mop head. This same technique can also be applied
to a cleaning sheet
attached to a mop head. For instance, as shown in Figs. 7 and 8, the contact
surface 352 of the
cleaning sheet 344 is the tangency point 362 of the curved bottom surface 350
of the cleaning
sheet 344 which contacts the straight line 356, this line being substantially
perpendicular to the
transverse axis 158 of the mop head. Likewise, the contact surface 452 of
cleaning sheet 444 of
Fig. 7 is the straight portion of the profile of the bottom surface of the
cleaning sheet 444 which
contacts the straight line 456, the straight line 456 being substantially
perpendicular to the
transverse axis 258 of the mop head. The previously described contact surfaces
of Figs. 5 to 8 are
illustrated with respect to bottom surfaces which are substantially smooth.
However, it is
contemplated that the present invention can be adapted for use with bottom
surfaces which are not
substantially smooth, but rather, have a surface texture disposed thereon. An
exemplary
pyramidal surface texture 74 on the bottom surface of the elastic pad 548 is
illustrated in Figs. 9
and 10. In such instances, the contact surfaces, dimensions and profiles
described for the various
bottom surfaces of the mop heads herein are determined with respect to the
tips 76 of the
projections 78 of the surface texture 74 by creating a theoretical bottom
surface profile 550 which
is tangent to each tip, as shown in Fig. 10. The straight line 56 is then
placed relative to the
theoretical bottom surface profile 550, to determine the width 53 of the
contact surface 52 of the
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textured bottom surface. The surface texture can be either random or
repeating. Surface textures
having other shaped projections (e.g., cylindrical) can also be used.
Referring again to Fig. 4, the width 53 of the contact surface 52 is
preferably less than
about 50 mm, and, more preferably, the width 53 of the contact surface 52 is
between about 2 mm
and about 50 mm. Most preferably, the width 53 of the contact surface 52 is
between about 2 mm
and about 20 mm. In addition to the size of the contact surface, the shape of
the profile of the
bottom surface 50 of the mop head 22 and/or the cleaning sheet 44 in
combination with the
previously described width 53 of the contact surface 52 influences whether a
repeated rocking
motion of the mop head is achieved during use. The profiles of the contact
surface 52 are
substantially curved (e.g., parabolic, hyperbolic, and other curved segments)
and are preferably
convex in shape, wherein the width 53 is a theoretical point contact or
tangency 62 as previously
discussed while for substantially straight contact surfaces (see, e.g., Fig.
6) the width 53 of the
contact surface is between about 2 mm and about 50 mm.
For substantially curved profiles at the contact surface 53, it is desirable
to provide a
profile having a substantially continuous radius of curvature 66, as shown in
Fig. 11, such that a
more purely circular arc is achieved. The radius of curvature 66 can be
determined for a
substantially curved bottom surface by passing an arc having a constant radius
through the
terminuses 70 of the bottom surface and the tangency 62 of the contact surface
52 of the bottom
surface. The radius of curvature 66 is preferably at least about 300 mm, and,
more preferably, is
at least about 1000 mm. Most preferably, the radius of curvature is between
about 300 mm and
about 1200 mm.
The combination of the shape of the profile (e.g., substantially curved or
substantially
straight) of the contact surface 52 and the width 53 of the contact surface 52
are preferably
combined with a gap 68 fonned between the straight line 56 defining the
contact surface 52 of
either the bottom surface of the mop head 22 or the bottom surface of the
cleaning sheet 44 and
the terminal point(s) 70 of the subject bottom surface. In other words, the
tenn "gap" is intended
to refer to the distance between the straight line 56 and the terminal point
70 of the bottom surface
of either mop head 22 or the cleaning sheet 44. A sufficient gap can ensure
that over a wide range
of operating conditions (e.g., operating angle between the handle and mop
head, mopping speed,
force applied by the user, etc.), the mop head maintains the desired rocking
motion. Generally for
both the mop head 22 and the cleaning sheet 44, the terminal points 70 are
defined by the leading
edge 24 or trailing edge 26, as shown in Fig. 4. Preferably, the gap 68 is at
least about 1.5 mm
and, more preferably, is between about 2 mm and about 10 mm. Most preferably,
the gap 68 is
between about 2 mm and about 5 mm. Thus, the gap, profile shape of the contact
surface, and the
width of the contact surface are interrelated to varying degrees and can be
changed as taught
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herein in order to provide a mop having a mop head which repeatedly rocks when
it is moved
forward and/or backward during any single continuous forward or backward
motion of the mop
head, such rocking motion beneficially improving the cleaning performance of
the cleaning sheet
44. The synergy between the gap 68 and curved profile of the bottom surface
can be represented
by the ratio of the radius of curvature 66 to the gap 68, wherein the ratio is
preferably between
about 0.5 and about 1000. More preferably, the ratio of the radius of
curvature 66 to the gap 68 is
between about I and about 600. Most preferably, the ratio of the radius of
curvature 66 to the
gap 68 is between about 350 and about 600.
While a mop head 22 having a bottom surface which is convexly curved is most
preferred, it is contemplated that bottom surfaces having a stepped profile,
such as that illustrated
in Fig. 12, can also provide the desired rocking motion so long as the width
653 of the linear
portion of the contact surface 652 defined by the straight line 56 is at least
about 2 mm. Each step
73 preferably has a longitudinally extending planar portion 74 adjacent a wall
75. While it is
preferred that a plurality of steps 73 are provided so that the cleaning sheet
is adequately
supported during use, it is contemplated that a single step 72 could also be
utilized.
As discussed, the bottom surface of the mop head 22 can be provided with a
profile
shape, profile size, and gap which produce the desired repeated rocking motion
of the mop head
during use. However, the combination of the cleaning sheet and the bottom
surface of the mop
head 22 can also be adapted to provide the previously described rocking motion
of the mop head
22. For example with reference to Fig. 13, a tiered structure 76 with a
plurality of steps 73 can be
used in combination with an elastic pad 748 having a substantially smooth
planar bottom surface,
wherein the tiered structure 76 is incorporated into or disposed adjacent to
the cleaning sheet 44 to
provide a bottom surface of the cleaning sheet having the same size and/or
profile characteristics
as previously described for the bottom surfaces of the mop head 22.
Alternatively, the cleaning
sheet 44 could include an insert having a curved bottom surface which provides
the bottom
surface of the cleaning sheet with the previously described curved profile
size and/or shape
surface characteristics. Accordingly, it will be appreciated that the profile
size, shape, and gap
previously described with respect to the bottom surface of the mop head 22 are
equally applicable
to the bottom surface of a cleaning sheet.
While cleaning sheets having low calipers are particularly suitable for use
with the
cleaning implements of the present invention, it is contemplated that a
cleaning sheet having a
high caliper can also be used, wherein the high caliper allows compression of
the cleaning sheet at
the leading and trailing edges of the mop head (as opposed to merely
conforming to the shape of
the bottom surface of the mop head, as shown in Fig. 7, for cleaning sheet
having a relatively low
caliper). This compression allows creation of a gap for rocking of the mop
head during use. The
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cooperation between the caliper of the cleaning sheet and the gap of the mop
head 22 can be
characterized by the ratio of the individual sheet caliper to the distance of
the gap 68 of the mop
head 22, as shown in Fig. 14. As used herein, the phrase "caliper" and its
derivatives is intended
to refer to the thickness of the cleaning sheet when measured according to
ASTMD5729-95,
wherein the presser foot pressure is 0.1 psig. Preferably the ratio of
individual sheet caliper to the
distance of the gap is between about 0.01 and about 0.65. More preferably, the
ratio the of
individual sheet caliper to the distance of the gap is between about 0.1 and
about 0.6, and, most
preferably, the ratio of the individual sheet caliper to the distance of the
gap is between about 0.25
and about 0.6. For instances where a high caliper sheet is used with a mop
head having a
convexly curved bottom surface with a radius of curvature, the ratio of the
radius of curvature to
individual sheet caliper is preferably between about 0.01 and 1800, and, more
preferably, is
between about 1 and about 1400. Most preferably, the ratio of radius of
curvature to individual
sheet caliper is between about 200 and about 1000.
In accordance with yet another aspect of the present invention, a floor mop
having a mop
head dimensioned to receive cleaning sheets which are sized for both hand
dusting and dusting
with a floor mop will now be described. Cleaning sheets suitable for use with
the floor mop 20
(such as those discussed more fully hereafter in Section III) are adapted to
attract and retain
various types of dust and other particulates. For instance, the cleaning
sheets are particularly
suited at attracting and retaining particles ranging in size from about 1 x
10' mm up to larger
sized particulates which can be 2 mm and greater in height. As such, these
cleaning sheets can be
particularly suited for dusting surfaces by hand in addition to use with a
cleaning implement, such
as the floor mop 20. In order to provide a user of a cleaning implement with
the greatest
flexibility of use, the mop head 22 of the floor mop 20 is preferably sized to
effectively retain a
cleaning sheet which can be used with both the floor mop 20 and for hand
dusting.
Such a cleaning sheet preferably has length (i.e., its longest dimension) to
width ratio of
between about 0.4 and about I and a sheet caliper of at least about 0.6 mm so
that the cleaning
sheet can adequately trap particles in both hand dusting and floor mopping
applications and so
that there is adequate surface area and depth for gripping the sheet during
hand dusting as well as
floor cleaning with the floor mop 20. More preferably, the caliper of the
cleaning sheet is
between about 0.6 nun and about 5 mm and most preferably is between about 0.8
mm and about 3
mm. The cleaning sheet preferably also has a length of at least about 400 mm
and more
preferably the length is between about 400 mm and about 500 mm. Accordingly,
the mop head
22 preferably has a length (i.e., the longest dimension of the mop head) to
width (i.e., the shortest
dimension of the mop head) ratio of between about 0.3 and about 1 so that the
hand dusting
cleaning sheet can also be adequately and effectively retained about the mop
head 22. More
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preferably, the mop head 22 has a length of at least about 400 mm. The above-
described
preferred cleaning sheet and mop head dimensions can be combined with a mop
head having
various types of bottom surfaces, such as a substantially flat bottom surface
or a mop head having
the textures, sizes and shapes previously described herein.
The present invention further encompasses articles of manufacture comprising
the above-
described hand dusting sheet (i.e. cleaning sheet) in association with a set
of instructions, which
can be combined with a package, carton, or other container. As used herein,
the phrase "in
association with" means the set of instructions is either directly printed on
the cleaning sheet itself
or presented in a separate manner including, but not limited to, a brochure,
print advertisement,
electronic advertisement, and/or verbal communication, so as to communicate
the set of
instructions to a consumer of the article of manufacture. The set of
instructions preferably
comprises the instruction to use the hand dusting sheet for hand dusting
and/or with a cleaning
implement, such as a floor mop, having a handle and a mop head. The set of
instructions can
further comprise instructions to use the hand dusting cleaning sheet with a
floor mop having a
mop head configured as previously described herein. For example, the
instruction can instruct
using the cleaning sheet with a floor mop having a mop head with a convexly
curved bottom
surface. Other instructions can instruct a use to assemble sections of a
handle of a floor mop to
complete assembly of the floor mop. Other instructions can instruct a user to
attach the cleaning
sheet to the mop head, move the floor mop, and then remove the cleaning sheet
from the mop
head.
In accordance with still yet another aspect of the present invention, a kit is
provided
comprising a mop head, or a cleaning sheet which when used with a mop head,
provides a bottom
surface having one of the previously described profiles for producing a
repeated rocking or
pivoting motion of the mop head during use. Still further, the kit preferably
includes a coupling,
such as the particularly preferred coupling 86 illustrated in Fig. 15, having
at least two, and, more
preferably, at least three, bores 88 which are angled relative to one another.
At least one bore 88
releasably receives at least one end of either the handle 32 or the universal
joint 30. More
preferably, at least one bore 88 has female threads 92 which threadably
engages male threads of
the handle 32 while the remaining two bores 88 are adapted to receive the end
of the extension 94
of the universal joint 30. The angled bores 88 of the coupling 86 allow
reorientation of the handle
32 relative to the mop head 22. For instance, the longitudinal axis of the
extension 94 of the
universal joint 30 might be substantially collinear with the longitudinal axis
of the handle 32 in a
first orientation, as shown in Fig. 16, while the longitudinal axis of the
extension 94 of the
universal joint 30 might be angled relative to the longitudinal axis of the
handle 32 in a second
orientation, as shown in Fig. 17. Reorientation of handle 32 relative to the
universal joint 30
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provides improved flexibility for cleaning hard to reach areas, such as the
intersection of a wall
and ceiling, etc.
The mop head 22 and universal joint 26 are preferably formed from ABS type-
polymers
(e.g., terpolymer from acrylonitrile), polypropylene or other plastic material
by injection molding.
The elastic pad 48 is preferably formed from polyurethane by molding. The mop
handle 32 can
be formed from aluminum, plastic, or other structural materials.
III. Cleaning Sheet
The present invention encompasses cleaning sheets comprising an additive that
is selected
to enhance the pick up and retention of particulate material from surfaces,
while minimizing the
amount of residue left on the surface being cleaned. If the type of additive
and level of additive on
the cleaning sheet are not carefully selected, the sheet will leave a residue
on the surface being
cleaned resulting in filming and streaking of the surface that is unacceptable
to consumers.
The cleaning sheets of the present invention typically have a total aggregate
basis weight
of at least about 20 g/m2, preferably at least about 40 g/m2, and more
preferably at least about 60
g/m2. The total aggregate basis weight of the present cleaning sheets is
typically no greater than
about 275 g/m2, preferably no greater than about 200 g/m2, and more preferably
no greater than
about 150 g/m2.
The cleaning sheets of the present invention can be made using either a woven
or
nonwoven process, or by forming operations using melted materials laid down on
forms,
especially in belts, and/or by forming operations involving mechanical
actions/modifications
carried out on films. The structures are made by any number of methods (e.g.,
spunbonded,
meltblown, resin bonded, heat-bonded, air-through bonded, etc.), once the
desired characteristics
are known. However, the preferred structures are nonwoven, and especially
those formed by
hydroentanglement and/or heat-bonding as is well known in the art, since they
provide highly
desirable open structures. Therefore, preferred cleaning sheets are nonwoven
structures having
the characteristics described herein. Materials particularly suitable for
forming the preferred
nonwoven cleaning sheet of the present invention include, for example, natural
cellulosics as well
as synthetics such as polyolefins (e.g., polyethylene and polypropylene),
polyesters, polyamides,
synthetic cellulosics (e.g., RAYON ), and blends thereof. Also useful are
natural fibers, such as
cotton or blends thereof and those derived from various cellulosic sources,
however these are not
preferred. Preferred starting materials for making the cleaning sheets of the
present invention are
synthetic materials, which may be in the form of carded, spunbonded,
meltblown, airlaid, or other
structures. Cleaning sheets comprising synthetic materials or fibers typically
have desirable
electrostatic properties, which is preferred. Particularly preferred are
polyesters, especially carded
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polyester fibers. The degree of hydrophobicity or hydrophilicity of the fibers
is optimized
depending upon the desired goal of the sheet, either in terms of type of soil
to be removed, the
type of additive that is provided, biodegradability, availability, and
combinations of such
considerations. In general, the more biodegradable materials are hydrophilic,
but the more
effective materials tend to be hydrophobic.
The cleaning sheets may be formed from a single fibrous layer, but preferably
are a
composite of at least two separate layers. As noted above, preferred cleaning
sheets in the present
invention include a variety of cleaning sheet structures, such as heat-bonded
cleaning sheets
and/or hydroentangled cleaning sheets.
The present cleaning sheets comprise an additive. The type and level of
additive is
selected such that the cleaning sheet has the ability to effectively pick-up
and retain particulate
material, while preferably maintaining the electrostatic properties of the
cleaning sheet and
minimizing the residue left on a surface being wiped with the cleaning sheet.
As such, the additive
is preferably non-cationic, as cationic additives can tend to diminish the
electrostatic properties of
the cleaning sheet.
Cleaning sheets useful in the present invention include, but are not limited
to, those
described in U.S. Patent No. 6,645,604, filed May 20, 1998 by
Fereshtehkhou et al. (Case 6664M); U.S. Patent No. 6,561,354, filed May
20, 1998 by Fereshtehkhou et al. (Case 6798M); U.S. Patent No. 5,525,397
issued June 11, 1996
to Shizuno et al.; EP 774,229 A2 published May 21, 1997; EP 777,997 A2
published June 11,
1997; and JP 09-224,895 published September 2, 1997; JP 09-313,416 published
December 9,
1997.
A. Preferred Heat-Bonded Cleanin Sheets
heets
A preferred heat-bonded cleaning sheet of the present invention preferably has
at least
two distinct regions of differing basis weight. In a preferred embodiment, the
present cleaning
sheet has two distinct regions of differing basis weight and comprises a first
basis weight region
of relatively high basis weight and a second basis weight region of relatively
low basis weight.
The first region of relatively high basis weight exhibits a basis weight of
typically at least about
80 g/m', preferably at least about 130 g/mZ, more preferably at least about
170 g/m', and even
more preferably at least about 200 g/m'-, and typically no greater than about
300 g/m'-, preferably
no greater than about 275 g/m2, more preferably no greater than about 250
g/mZ, and even more
preferably no greater than about 240 g/mZ. This first region of relatively
high basis weight is
preferably located in the middle of the cleaning sheet, in the Y dimension, as
is shown in Fig. 23.
The first region of relatively high basis weight typically accounts for at
least 30%, preferably at
least about 40%, more preferably at least about 45%, and even more preferably
at least about
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50%, of the area of the cleaning sheet. The first region of relatively high
basis weight also
typically accounts for no greater than about 90%, preferably no greater than
about 80%, more
preferably no greater than about 70%, and even more preferably no greater than
about 60%, of the
area of the cleaning sheet. The cleaning sheet will also preferably have a
second region of
relatively low basis weight, typically divided between the sides of the sheet
as shown in Fig. 23,
of typically no greater than about 70%, preferably no greater than about 60%,
more preferably no
greater than about 55%, and even more preferably no greater than about 50%,
and typically at
least about 10%, preferably at least about 20%, more preferably at least about
30%, and even
more preferably at least about 40%, of the area of the cleaning sheet. In
another aspect of the
invention, there is only one macroscopic basis weight region comprising the
higher basis weight
material.
The present cleaning sheets preferably comprise brushy filaments as depicted
in the
cleaning sheet shown in Fig. 23 and as depicted in the process shown in Fig.
24. The brushy
filaments are attached to the cleaning sheet to aid in particulate pick-up and
retention. The brushy
filaments are preferably formed from a bundle of polyester continuous
filaments.
In regard to a cleaning sheet for use with an implement comprising a mop head
and a
handle as described herein, a region of relatively high basis weight is
preferably located on the
sheet such that the region of relatively high basis weight contacts the
surface being cleaned during
a typically cleaning method by wiping the surface with the cleaning sheet. The
region of relatively
low basis weight is preferably located on the sheet such that the region of
relatively low basis
weight is engaged by a holding means/gripping means located in a mop head of
an implement.
Process for Making Preferred Heat-Bonded Cleaning Sheets
A process for making heat-bonded cleaning sheets that are useful in the
present invention
is depicted in Fig. 24. During this process, a continuous first web 310 made
of polypropylene
having a width of 210mm and a basis weight of 30g/m2 is continuously fed from
left to right as
viewed in the diagram. Simultaneously, a tow 312 comprising a bundle of 2,000 -
100,000
polyester continuous filaments 315 each of 2 - 30 denier is continuously fed
from left to right as
viewed in the diagram. The tow 312 is opened or fibrillated by a set of
expanding rolls 311 to
form a continuous second web having a desired width and thereafter placed upon
the first web
310. The first web 310 and the second web 312 are transported to a heating
emboss machine 313
in which they are compressed together under heating and integrally heat-sealed
along thereby
formed heat-seal lines 316 transversely extending to form a continuous
composite third web 314.
The heat-seal lines 316 are provided so as to be spaced apart one from another
by a distance d as
measured longitudinally of the third web, i.e., intermittently arranged
longitudinally of the third
web 314. Thereafter, the second web 312 is cut by a first cutter 317 along a
middle line extending
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parallel to and between each pair of adjacent heat-seal lines 3 16 in two.
Then, the first web 310 is
cut by a second cutter 318 into a desired length. In this manner, the
individual cleaning sheets I
are obtained from the third web 314. In this process, the individual basic
sheets 10 are obtained
from the first web 310, the brushy filaments are obtained from the second web
312, the individual
filaments 15 of the brushy filaments are obtained from the continuous
filaments 315 and the
anchoring portions 16 are provided by the heat-seal lines 316. Preferably,
each of the heat-seal
lines 316 has a width of 2 - 10mm and is spaced apart from the adjacent heat-
seal line by a
distance d of 20 - 200mm. The brushy filaments or the second web or the tow
312 prior to
formation of these brushy filaments are sprayed or rolled with an additive as
described herein at
an appropriate step of the process. In a section of the first web 310 to be
cut by the second cutter
318, a distance D between each pair of adjacent heat-seal lines 316 may be
dimensioned to be
longer than the distance d to obtain a relatively large marginal region 7 (as
shown in FIGS. 19 and
20) facilitating the cleaning sheet 1 to be mounted onto a mop head of a
cleaning implement. In
this case, the section defined between two adjacent heat-seal lines spaced
from each other by the
distance D necessarily provides relatively long brushy filaments and these
brushy filaments must
be cut to a length in conformity of the remainder brushy filaments. According
to the process
illustrated, a length of each filament 15 hanging down from the anchoring
portion 16 corresponds
to about 1/2 to about 9/10 of the distance d. If desired, a length of the
second web 312 fed on the
section of the first web 310 defined between each pair of adjacent heat-seal
lines 316 may be
dimensioned to be longer than the distance d in order to obtain the filaments
15 longer than 1/2 of
the distance d.
In the process for making heat-bonded cleaning sheets according to the present
invention,
particular types of materials used as the basic sheet 10 and the brushy
filaments are not critical
insofar as they are mutually heat-sealable. However, it is generally
preferable to use thermoplastic
synthetic resin as the materials for these components. Additionally, the first
web 310 and the
second web 312 made of thermoplastic synthetic resin may be mixed with non-
heat-sealable
filaments such as rayon. Such non-heat-sealable filaments will be embedded in
the material heat-
sealed along the respective heat-seal lines 316 and fixed thereto.
Furthermore, continuous plastic
film may be employed for nonwoven fabric as the first web 310.
The process allows for the density of the brushy filaments planted on the
basic sheet to be
easily improved merely by increasing the number of filaments constituting the
tow or web, since
the tow or web comprising the heat-sealable filaments and the basic sheet of
the heat-sealable
nature are heat-sealed together followed by transversely cutting the tow or
web to form the brushy
filaments of said cleaning sheet.
B. Preferred Hydroentangled Cleaning Sheets
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Hydroentangled cleaning sheets are particularly useful in the present
invention due to
their ability to effectively pick-up and retain particulate material from
surfaces. In particular,
nonwoven cleaning sheets made by a hydroentanglement process are highly
effective. The hydro-
entanglement process is well-described in U.S. Patent No. 3,537,945. A
hydroentanglement
process typically involves treating a web of fibers with jets of high pressure
water or other liquid
which serves to "entangle" the fibers, i.e., to force the fibers from a
position of alignment into one
where the fibers individually are at various angles with respect to each other
and become
physically entangled to produce a hydroentangled fabric. The hydroentangled
fabric is
exceptionally strong and soft, and it also contains voids which occur between
the physical
junctions of the fibers which are highly effective in assisting the pick-up
and retention of dust and
particles. Moreover, a hydroentanglement process can be adjusted to produce a
hydroentangled
fabric which has visible apertures which also enhance dust and particle pick-
up and retention.
The present invention encompasses a wide variety of structures of
hydroentangled
cleaning sheets. The cleaning sheets can have relatively uniform basis weight
across the entire
area of the sheet, or the cleaning sheets can have discrete regions of
differing basis weight. In
addition, the cleaning sheets can have relatively flat surfaces, or the
cleaning sheets can exhibit
macroscopic three-dimensionality.
To enhance the integrity of the present hydroentangled cleaning sheets, it is
preferred to
include a polymeric net (referred to herein as a "scrim" material) that is
arranged with the fibrous
material, e.g., though lamination via heat or chemical means such as
adhesives, via
hydrogentanglement. Scrim materials useful herein are described in detail in
U.S. Patent No.
4,636,419, which is incorporated by reference herein. The scrims may be formed
directly at the
extrusion die or can be derived from extruded films by fibrillation or by
embossment, followed by
stretching and splitting. The scrim may be derived from a polyolefin such as
polyethylene or
polypropylene, copolymers thereof, poly(butylene terephthalate), polyethylene
terephthalate,
Nylon 6, Nylon 66, and the like. Scrim materials are available from various
conunercial sources.
A preferred scrim material useful in the present invention is a polypropylene
scrim, available from
Conwed Plastics (Minneapolis, MN).
Hydroentangled cleaning sheets suitable for the present invention include
those described
in U.S. Patent No. 6,645,604, filed May 20, 1998 by Fereshtehkhou et al.
(Case 6664M); U.S. Patent No. 6,561,354, filed May 20, 1998 by
Fereshtehkhou et al. (Case 6798M); and U.S. Patent No. 5,525,397 issued June
11, 1996 to
Shizuno et al.
i. Optional Multiple Basis Weig.,hts
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Hydroentangled cleaning sheets useful in the present invention can have at
least two
regions, where the regions are distinguished by basis weight. In particular,
the cleaning sheet can
comprise one or more high basis weight regions having a basis weight of from
about 30 to about
120 g/m2 (preferably from about 40 to about 100 g/m2, more preferably from
about 50 to about
90 g/m2, still more preferably from about 60 to about 80 g/m2) and one or more
low basis weight
regions, wherein the low basis weight region(s) have a basis weight that is
not more than about
80% of the basis weight of the high basis weight region(s). Preferred cleaning
sheets in this
regard comprise a continuous high basis weight region and a plurality of
discontinuous regions
circumscribed by the continuous high basis weight region, wherein the
discontinuous regions are
disposed in a nonrandom, repeating pattern and have a basis weight of not more
than about 80%
of the basis weight of the continuous region.
Preferably, the low basis weight region(s) of the cleaning sheet will have a
basis weight
of not more than about 60%, more preferably not more than about 40%, and still
more preferably
not more than about 20%, of the basis weight of the high basis weight
region(s). The cleaning
sheets will preferably have an aggregate basis weight of from about 20 to
about 110 g/m2, more
preferably from about 40 to about 100 g/m2, still more preferably from about
60 to about 90
g/m2. With respect to the low basis weight region(s), it is preferred that the
basis weight not be
zero in such regions such that macroscopic apertures are present. This is
because soil will be
allowed to penetrate completely through the cleaning sheet, and will not be
retained therein. In
other words, the entrapment level of the sheet will not be optimized in such
situations.
In those embodiments where a continuous high basis weight region surrounds
discrete
low basis weight regions, it is preferred that at least about 5% of the
cleaning sheet's total surface
area be the low basis weight regions. More preferably, at least about 10%,
still more preferably
at least about 15%, still more preferably at least about 20%, still more
preferably at least about
30%, of the cleaning sheet's total surface area will be the low basis weight
regions. In those
embodiments where discrete high basis weight regions are surrounded by a
continuous low basis
weight region, it is preferred that at least about 5% of the cleaning sheet's
total surface area be the
discrete high basis weight regions. More preferably, at least about 10%, still
more preferably at
least about 15%, still more preferably at least about 20%, still more
preferably at least about 30%,
of the cleaning sheet's total surface area will be the high basis weight
regions.
In those preferred embodiments having a continuous high basis weight region
surrounding discrete, low basis weight regions, the discrete low basis weight
regions may be
staggered in, or may be aligned in, either or both of the X and Y directions.
Preferably, the high
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basis weight essentially continuous network forms a patterned network
circumjacent the discrete
low basis weight regions, although, as noted, small transition regions may be
accommodated.
It will be clear to one skilled in the art that there may be small transition
regions having a
basis weight intermediate the basis weights of the high basis weight region(s)
and the low basis
weight region(s), which transition regions by themselves may not be
significant enough in area to
be considered as comprising a basis weight distinct from the basis weights of
either adjacent
region. Such transition regions are within the normal manufacturing variations
known and
inherent in producing a structure according to the present invention. It will
also be recognized
that within a given region (whether high or low basis weight), ordinary and
expected basis weight
fluctuations and variations may occur, when such given region is considered to
have one basis
weight. For example, if on a microscopic level, the basis weight of an
interstice between fibers is
measured, an apparent basis weight of zero will result when, in fact, the
basis weight of such
region is greater than zero. Again, such fluctuations and variations are a
normal and expected
result of the manufacturing process.
Fig. 25 is a photograph of a portion of a preferred nonwoven sheet of the
present
invention having a continuous high basis weight region surrounding discrete
low basis weight
regions. While no call-out numbers are shown, it is seen that the high basis
weight continuous
region appears as the light network and the low basis weight regions are the
darker discrete
regions. Fig. 26 is plan view of a portion of a nonwoven sheet 3 to further
depict this aspect of
the sheet shown in Fig. 25. In particular, in Fig. 26, nonwoven sheet 3 has a
continuous high
basis weight region 5 and discrete low basis weight regions 4. In this
representative illustration,
an optional scrim material is not shown. While the low basis weight regions 4
are depicted as
being of essentially the same size and of a single well defined shape, these
regions may be of
differing sizes to facilitate entrapment of particles of varying size and
shape. Also, it will be
recognized that the shape of the low basis weight regions 4, and accordingly
the continuous high
basis weight region 5, may vary throughout the structure.
Differences in basis weights (within the same structure 3) between the high
and low basis
weight regions 5 and 4 of at least 20% are considered to be significant, and
define distinct regions
for purposes of the present disclosure. For a quantitative determination of
basis weight in each of
the regions 5 and 4, and hence a quantitative determination of the differences
in basis weight
between such regions 5 and 4, a quantitative method, such as image analysis of
soft X-rays as
disclosed in U.S. Patent No. 5,277,761, issued to Phan et al. on January 11,
1994, may be
utilized, This method is also applicable where
the regions of high and low basis weight are not arranged in a
continuous/discrete pattern.
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The relative area of the low basis weight regions and high basis weight region
can be
measured quantitatively using image analysis techniques as described in U.S.
Patent No. 6,645,604, filed May 20, 1998 by Fereshtehkhou et al. (Case 6664M).
ii. Optional Macroscopic Three-Dimensionality
In one embodiment the cleaning sheets will also be macroscopically three-
dimensional.
These sheets are preferably relatively open structures as contrasted with,
e.g., paper towels. In
one such preferred embodiment, the macroscopically three-dimensional cleaning
sheets have a
first surface and a second surface and comprise a scrim or other contractible
material. In one
such preferred embodiment, the cleaning sheet has a first outward surface and
a second outward
surface and comprises a contractible (preferably a scrim) material, wherein
the Average Peak to
Peak Distance of at least one outward surface is preferably at least about 1
mm and the Surface
Topography Index of that surface(s) is preferably from about 0.01 to about 5.
Methods for
measuring Average Peak to Peak Distance and Average Height Differential are
described in
detail in U.S. Patent No. 6,645,604, filed May 20, 1998 by
Fereshtehkhou et al. (Case 6664M),
Regardless of the configuration of the cleaning sheets, the Average Peak to
Peak Distance
of at least one outward surface will preferably be at least about 1 mm, more
preferably at least
about 2 mm, and still more preferably at least about 3 mm. In one embodiment,
the Average Peak
to Peak distance is from about 1 to about 20 mm, particularly from about 3 to
about 16 mm, more
particularly from about 4 to about 12 mm. The Surface Topography Index of at
least one outward
surface will preferably be from about 0.01 to about 10, preferably from about
0.1 to about 5, more
preferably from about 0.2 to about 3, still more preferably from about 0.3 to
about 2. At least one
outward surface will preferably have an Average Height Differential of at
least about 0.5 mm,
more preferably at least about 1 mm, and still more preferably at least about
1.5 mm. The
Average Height Differential of at least one outward surface will typically be
from about 0.5 to
about 6 mm, more typically from about 1 to about 3 mm.
C. Non-Apertured Cleaniniz Sheets Having Non-Random Macroscopic Three-
Dimensional Character
Preferred cleaning sheets herein also include non-apertured cleaning sheets
having non-
random macroscopic three-dimensional character. Such cleaning sheets are
described in detail in
copending U.S. Publication No. 20010029966, filed November 30, 2000 by Wong et
al..
D. Other Cleaning Sheets
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Other cleaning sheets which are useful in the present invention include those
which are
spun-bonded, meltblown, airlaid, and the like.
IV. Additive
A number of additive materials can be suitable for incorporation into the
cleaning sheets
of the present invention. Preferred additives of the present invention that
are particularly useful
with the present cleaning sheets are polymeric additives, especially those
with specific adhesive
characteristics such as specific Tack Values, Adhesive Work Values,
Cohesion/Adhesion Ratios,
Stringiness Values, Tg Values, and/or molecular weight. Other additive
materials that are optional
in the present invention include, but are not limited to waxes, oils, powders,
and mixtures thereof.
The additive material is selected in order to improve the pick-up of fine
particulate matter such as
dust, lint, and hair, and especially larger particulate matter typically found
on household floors
and surfaces such as crumbs, dirt, sand, hair, crushed food, grass clippings
and mulch. In addition,
the type and amount of the additive material is carefully selected in order to
improve particulate
pick-up of the cleaning sheet, while maintaining the ability of the cleaning
sheet to easily glide
across the surface being cleaned. If the cleaning sheet is too tacky as a
result of the additives
incorporated therein, the cleaning sheet will not easily glide across the
surface, leading to
consumer dissatisfaction.
A. Polymeric Additive
The present invention encompasses the present cleaning sheets impregnated with
a
polymeric additive selected from a variety of acceptable polymeric additives,
and mixtures
thereof. Suitable polymeric additives include, but are not limited to, those
selected from the group
consisting of pressure sensitive adhesives, tacky polymers, and mixtures
thereof. Suitable pressure
sensitive adhesives comprise an adhesive polymer, which is optionally in
combination with a
tackifying resin, plasticizer, and/or other optional components. Suitable
tacky polymers include,
but are not limited to, polyisobutylene polymers, N-decylmethacrylate
polymers, and mixtures
thereof.
Slip agents, such as water emulsions of natural or synthetic high-melting
point waxes or
of natural fatty acid esters or amides (e.g. oleamide, euracamide, stearamide,
or ammonium
stearate) as described in U.S. Patent No. 5,198,292 issued March 30, 1993 to
Lerner et al., which
is incorporated herein by reference, can optionally be incorporated in the
present polymeric
additives. However, in a preferred embodiment, the present polymeric additives
are essentially
free of slip agents.
Polymeric additives tend to provide even more effective particulate pick-up,
as compared
to wax- and/or oil-type additives, especially in regard to larger particulate
material typically found
on household surfaces such as crumbs, sand, dirt, crushed food, grass
clippings and mulch, and
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the like. However, if the type and amount of a polymeric additive is not
carefully selected, the
resultant cleaning sheet impregnated with the polymeric additive can become
too sticky, resulting
in hand feel that is unacceptable to consumers. Furthermore, if the polymeric
additive is not
carefully selected, the cleaning sheet will generate a coefficient of friction
that is too great,
resulting in a decrease in the ability of the cleaning sheet to smoothly glide
across the surface
being cleaned. To the average consumer who cleans household surfaces with the
present cleaning
sheets, the glide of the sheet is aesthetically very important.
1. Adhesive Characteristics of Polymeric Additive
The adhesive characteristics of the present polymeric additives are important
in order to
create a cleaning sheet that has effective particulate pick-up performance,
acceptable surface glide
performance, and aesthetic appeal (e.g. hand feel). Adhesive characteristics
of the present
polymeric additives can be measured using a texture analyzer. A suitable
texture analyzer is
commercially available from Stable Micro Systems, Ltd. in Godalming, Surrey UK
under the
trade name TA.XT2 Texture Analyser. A test method ("Texture Analyzer Method")
for
measuring the adhesive characteristics is described hereinafter in Section
V.A. Fig. 27 illustrates a
texture analyzer used in this test method.
The adhesive characteristics measured herein include Tack Value, Adhesive Work
Value,
Cohesive Strength, Adhesive Strength, Cohesive/Adhesive Ratio, and Stringiness
Value. The
polymeric adhesives preferred herein, including pressure sensitive adhesives
and/or tacky
polymers, exhibit certain adhesive characteristics in order to provide a
cleaning sheet that has
acceptable performance and aesthetic appeal.
a. Adhesive Work Value
As used herein, the term "Adhesive Work Value" refers to the total bonding
force, both
adhesive and cohesive, of the present polymeric additive. The polymeric
additive of the present
invention preferably has a Adhesive Work Value within a specified range in
order to provide a
cleaning sheet that has effective performance and aesthetic appeal. If the
Adhesive Work Value is
too high, the cleaning sheet containing the polymeric additive tends to be too
sticky and does not
smoothly glide across the surface being cleaned. On the other hand, if
Adhesive Work Value is
too low, the cleaning sheet containing the polymeric additive tends to exhibit
insufficient pick-up
of large particulate material.
Adhesive Work Value is measured by the texture analyzer according to the
Texture
Analyzer Method in Section V.A. Fig. 28 illustrates a curve that is generated
from the Texture
Analyzer Method. The total area under the curve between line 111 and line 113
represented in the
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graph is equal to the Adhesive Work Value of the polymeric additive being
tested. Adhesive
Work Value is measured in terms of grams of force x mm.
b. Tack Value
As used herein, the term "Tack Value" refers to the maximum adhesive strength
of the
polymeric additive. The polymeric additive of the present invention preferably
has a Tack Value
within a specified range in order to provide a cleaning sheet that has
effective performance and
aesthetic appeal. If the Tack Value is too high, the Adhesive Work Value also
tends to be too
high, resulting in a cleaning sheet that is too sticky and does not glide
smoothly across the surface
being cleaned. On the other hand, if Tack Value is too low, the Adhesive Work
Value also tends
to be too low, resulting in a cleaning sheet that tends to exhibit
insufficient pick-up of large
particulate material.
Tack Value is measured by the texture analyzer according to the Texture
Analyzer
Method in Section V.A. Fig. 28 illustrates a curve that is generated from the
Texture Analyzer
Method. The peak force represented by line 114 in the graph is equal to the
Tack Value of the
polymeric additive being tested. Tack Value is measured in terms of grams of
force.
c. Cohesive/Adhesive Ratio
As used herein, the term "Cohesive/Adhesive Ratio" refers to a ratio between
the
"Cohesive Strength" and the "Adhesive Strength" of a polymeric additive.
"Cohesive Strength"
refers to the ability of the polymeric additive to bind to itself. "Adhesive
Strength" refers to the
ability of the polymeric additive to bind to other materials, such as cleaning
sheets, large
particulate material, and the like. The Cohesive/Adhesive Ratio relates to the
balance between
these two forces. The polymeric additive of the present invention preferably
has a
Cohesive/Adhesive Ratio within a specified range in order to provide a
cleaning sheet that has
effective performance and aesthetic appeal. If the Cohesive/Adhesive Ratio is
too high, a cleaning
sheet containing the polymeric additive tends to exhibit insufficient large
particulate pick-up. On
the other hand, if Cohesive/Adhesive Ratio is too low, some of the polymeric
additive tends to
transfer from the cleaning sheet to the surface being cleaned, resulting in
residue left on the
surface and poor glide characteristics of the cleaning sheet.
Cohesive Strength and Adhesive Strength are measured by the texture analyzer
according
to the Texture Analyzer Method in Section V.A. Fig. 28 illustrates a curve
that is generated from
the Texture Analyzer Method. The area under the curve after the peak force -
i.e. the area under
the curve between line 112 and line 113 - represented in the graph is equal to
the Cohesive
Strength of the polymeric additive being tested. The area of the curve before
the peak force - i.e.
the area under the curve between line 111 and line 112 - represented in the
graph is equal to the
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Adhesive Strength of the polymeric additive. The Cohesive/Adhesive Ratio is
simply calculated
by dividing the Cohesive Strength by the Adhesive Strength, which results in a
unitless ratio.
d. Stringiness Value
As used herein, the term "Stringiness Value" refers to the elasticity of the
polymeric
additive. The polymeric additive of the present invention preferably has a
Stringiness Value
within a specified range in order to provide a cleaning sheet that has
effective performance and
aesthetic appeal. If the Stringiness Value is too high, the polymeric additive
tends to hold onto the
surface being cleaned and the glide performance of the cleaning sheet is
reduced. On the other
hand, if Stringiness Value is too low, the cleaning sheet containing the
polymeric additive tends to
exhibit insufficient large particulate pick-up.
Stringiness Value is measured by the texture analyzer according to the Texture
Analyzer
Method in Section V.A. Fig. 28 illustrates a curve that is generated from the
Texture Analyzer
Method. The distance in which the probe of the texture analyzer is in contact
with the polymeric
additive being tested represented by line 112 in the graph is equal to the
Stringiness Value of the
polymeric additive. Stringiness Value is measured in terms of millimeters.
2. Pressure Sensitive Adhesives
Preferred polymeric additives in the present invention are pressure sensitive
adhesives.
Pressure sensitive adhesives suitable in the present invention generally
comprise an adhesive
polymer that is optionally in combination with a tackifying resin,
plasticizer, and/or other optional
ingredients. Pressure sensitive adhesives typically comprise an adhesive
polymer, co-polymer, or
mixtures of polymers. Preferred pressure sensitive adhesives comprise a cross-
linked polymer. A
preferred pressure sensitive adhesive comprises a cross-linked acrylate
polymer and is essentially
free of tackifiers, plasticizers, slip agents, or other resins.
a. Adhesive Polymer and/or Copolymer
Pressure sensitive adhesives suitable as polymeric additives of the present
invention
preferably comprise adhesive polymers and copolymers of synthetic resins,
rubbers, polyethylene,
polypropylene, polyurethane, acrylics, vinyl acetate, ethylene vinyl acetate
and polyvinyl alcohol.
Suitable adhesive polymers include, but are not limited to, block co-polymers
containing
polystyrene endblocks, and polyisoprene, polybutadiene, and/or poly ethylene-
butylene
midblocks; polyolefins such as polyethylene, polypropylene, amorphous
polypropylene,
polyisoprene, and polyethylene propylene; ethylene-vinylacetate copolymers;
poly(vinyl
ethylene-co-1,4-butadiene); natural rubber [poly cis-isoprene]; polyacrylic
acids, preferably 2-
ethylhexylacrylate and iso-octlyacrylate, and polymethacrylic acid or their
salt;
polydimethylsiloxane, polydiphenylsiloxane, poly methyl phenyl siloxane;
polyvinyl alcohol; and
mixtures thereof. Preferred pressure sensitive adhesives comprise a cross-
linked adhesive
-25-
polymer. A preferred pressure sensitive adhesive comprises a cross-linked
acrylate adhesive
polymer and is essentially free of tackifying resins, plasticizers, slip
agents, or other resins.
Adhesive polymers useful for the present invention can further include
thermoplastic
polymers such as A-B-A triblock copolymers, A-B diblock copolymers, A-B-A-B-A-
B
multiblock copolymers, radial block copolymers and grafted versions thereof;
homopolymers,
copolymers and terpolymers of ethylene; and homopolymers, copolymers and
terpolymers of
propylene; and mixtures thereof. Radial block copolymers include Y-block and
star polymers as
well as other configurations. The A-B-A block copolymers useful herein are
those described in
U.S. Pat. No. 4,136,699 issued Jan. 30, 1979 to Collins et al.
Examples include those polymers available under the KratonTm G series from
Shell
Chemical Co. in Houston, Tex. There are various grades available including
KratonTM G-1726,
KratonTM G-1650, KratonTM G-1651, KratonTM G-1652, KratonTM G-1657, all
saturated A-B
diblock/A-B-A triblock mixtures with ethylene/butylene midblocks; KratonTM D-
1112 a high
percent A-B diblock linear styrene-isoprene-styrene polymer; KratonTM D-1107
and KratonTM D-
1111, primarily A-B-A triblock linear styrene-isoprene-styrene block
copolymers; KratonTM
D4433X, a linear styrene-isoprene-styrene "SIS" block copolymer with an oil
content of 30% by
weight and KratonTM D 1184, a high molecular weight styrene-buradiene-styrene
"SBS" block
copolymer both available from Shell Chemical Co.; StereonTM 840A and StereonTM
841A, A-B-
A-B-A-B multiblock SBS block copolymers available from Firestone in Akron,
Ohio;
EuropreneTM Sol T-193B, a linear SIS block copolymer available from Enichem
Elastomers in
New York, N.Y.; EuropreneTM Sol T-190, a linear styrene-isoprene-styrene block
copolymer and
EuropreneTM Sol T-163, a radial SBS block copolymer both also available from
Enichem
Elastomers; VectorTM 4461-D, a linear SBS block copolymer available from Exxon
Chemical Co.
in Houston, Tex.; VectorTM 4111, 4211 and 4411, fully coupled linear SIS block
copolymers
containing different weight percentages of styrene endblock; and VectorTM
4113, a highly coupled
linear SIS block copolymer also available from Exxon Chemical Co.; and DPX-
550, DPX-551
and DPX-552 radial SIS block copolymers available from Dexco Polymers in
Houston, Tex. This
list in not exclusive and there are numerous grades of block copolymers
available from various
sources for pressure sensitive adhesives, especially hot melt pressure
sensitive adhesives. 'These
polymers may be used alone, or in any combinations. These polymers are useful
from about 5% to
about 90% by weight in the polymeric composition.
Other adhesive polymers include a substantially linear copolymer having the
general
configuration A-B-A. wherein the A block can be polystyrene and the B block
can be ethylene-
butylene, ethylene-propylene, isoprene, butadiene or mixtures thereof, and
preferably the B block
is ethylene-butylene or ethylene-propylene. Adhesive polymers of this type,
such as KratonTM G-
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1651, have twice the molecular weight of conventional styrene-
ethylene/butylene-styrene (S-EB-
S) block copolymers also used in pressure sensitive adhesives. This copolymer
is typically present
in amounts of from about 2% to about 20% by weight, preferably from about 5%
to about 20%,
by weight of the pressure sensitive adhesive.
Other adhesive polymers include lower molecular weight block copolymers that
can be
utilized with the high molecular weight block copolymers. Some examples are A-
B-A triblock
copolymers, A-B diblock copolymers, A-B-A-B-A-B multiblock copolymers, radial
block
copolymers, and grafted versions of such copolymers including Shell Chemical's
TKG-101 and
RP-6912. Such A-B-A block copolymers are disclosed in Collins et al., U.S.
Pat. No. 4,136,699.
Some of these block copolymers are commercially available from Shell Chemical
Co. under the
KratonTM G series which are S-EB-S block copolymers.
Other useful adhesive polymers include atactic polyalphaolefins such as those
available
from Rexene Products Co. in Dallas, Tex. under the tradename of RextacTM such
as RT-2280 and
RT-2315 and RT-2585 having various amounts of ethylene and homogeneous linear
or
substantially linear interpolymers of ethylene with at least one C2 to C20
alphaolefin, further
characterized by each said interpolymer having a polydispersity less than
about 2.5 including such
polymers as ExactTM 5008, an ethylene-butene copolymer, ExxpolTM SLP-0394, and
ethylene-
propylene copolymer, ExactTM 3031, an ethylene-hexene copolymer, all available
from Dow
Chemical Co. in Midland, Mich. These polymers may have to be used in small
concentrations if
utilized with such block copolymers as KratonTM G-1651 to maintain
compatibility without phase
separation or glutinous, gel-like compositions. These concentrations can be as
low as 5% by
weight of the pressure sensitive adhesive.
Other adhesive polymers can be useful in the pressure sensitive adhesives of
the present
invention including ethylene vinyl acetate copolymers such as E1vaxTM 410, a
14% vinyl
acetate/400 melt index copolymer and ElvaxTM 210, a 28% vinyl acetate/400 melt
index
copolymer, both available from DuPont Chemical Co. in Wilmington, Del.;
EscoreneTM UL 7505
an ethylene vinyl acetate copolymer available from Exxon Chemical Co.;
UltratheneTM UE 64904
available from Quantum Chemical Co., U.S.I. Division in Cincinnati, Ohio; and
AT 1850M
available from AT Polymers & Film Co. in Charlotte, N.C. Copolymers of
ethylene and methyl
acrylate (methacrylates as well as acrylates) are also useful including
OptemaTM TC-140, XS-
93.04 and TC-221 available from Exxon Chemical Co.; LotrylTM 28 MA 175 and 35
MA 05 1000
available from Elf Atochem North America in Philadelphia, Pa. Ethylene methyl
acrylate
copolymers are also available from Chevron under the tradename of EmacTM and
from Quantum
Chemical Co. under the tradename of AcrytheneTM. Copolymers of ethylene and n-
butyl acrylate
are also useful in the pressure sensitive adhesives of the present invention.
They are available
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from Quantum Chemical Co. under the tradename of EnatheneTM including EA80808,
EA 89821
and EA89822; from Elf Atochem North America under the tradename of LotrylTM
including 35
BA 900 and 35 BA 1000; from Exxon Chemical Co. under the tradename of
EscoreneTM
including XW-23.AH and XW-22. These adhesive polymers can also have to be used
in small
concentrations with some of the block copolymers such as KratonTM G-1651.
In a preferred embodiment, the pressure sensitive adhesive comprises an
adhesive
polymer that is an acrylic adhesive polymer selected from a wide variety of
polymers and
copolymers derived from acrylic and/or methacrylic acid, or ester, amide and
nitrile derivatives
thereof. Mixtures of different polymers and copolymers can be used. These
polymers and
copolymers preferably have a glass transition temperature of less than about 0
C so that the mass
of polymer is tacky at ambient temperatures. Examples of useful acrylate-based
adhesive
polymers include homopolymers and copolymers comprising isooctylacrylate, 2-
ethylhexylacrylate, isoamylacrylate, nonylacrylate and butylacrylate and their
copolymers or
terpolymers with acrylic acid, methacrylic acid, acrylamide, methacrylamide,
acrylonitrile and
methacrylonitrile. It is also possible to incorporate nonpolar acrylic
monomers whose
homopolymers have a relatively high T. such as, for example, isobornylacrylate
(see, e.g., WO
95/13,331 and WO 95/13,328).
Other adhesive polymers include polyamides; polyesters; polyvinyl alcohols and
copolymers thereof; polyurethanes; polystyrenes; polyepoxides; graft
copolymers of vinyl
monomers and polyalkylene oxide polymers and; aldehyde containing resins such
as phenol-
aldehyde, urea- aldehyde, melamine-aldehyde and the like.
b. Optional Tackifyiniz Resins
Suitable pressure sensitive adhesives can optionally be formulated with
tackifying resins
in order to improve adhesion and introduce tack into the pressure sensitive
adhesive, to achieve
the adhesive characteristics desired herein. Such resins include, among other
materials, (a) natural
and modified resins, (b) polyterpene resins, (c) phenolic modified hydrocarbon
resins, (d)
coumarone-indene resins, (e) aliphatic and aromatic petroleum hydrocarbon
resins, (f) phthalate
esters and (g) hydrogenated hydrocarbons, hydrogenated rosins, and
hydrogenated rosin esters.
Tackifying resins in hot melt adhesives that are solid at room temperature,
but melt below
application temperatures are preferred, since these resins lower the viscosity
on application
resulting in improved distribution and anchoring of the adhesive to the
substrate, while not having
excessive fluidity at ambient temeprature during usage. Preferably, these
resins have a melting
point between about 35 C and about 200 C, more preferably between about 50 C
and about
150 C.
While tackifying resins are preferable for use in hot melt pressure sensitive
adhesives,
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tackifying resins can also be utilized in other types of pressure sensitive
adhesives as well. The
tackifying resins useful herein further include aliphatic, cycloaliphatic and
aromatic hydrocarbons
and modified hydrocarbons and hydrogenated derivatives; terpenes and modified
terpenes and
hydrogenated derivatives; rosins and modified rosins and hydrogenated
derivatives; and mixtures
thereof. They are also available with differing levels of hydrogenation, or
saturation which is
another commonly used term. Useful examples include EastotacTM H-100, H-115
and H-130 from
Eastman Chemical Co. in Kingsport, Tenn. which are partially hydrogenated
cycloaliphatic
petroleum hydrocarbon resins with varying degress of hardness. These are
available in the E
grade, the R grade, the L grade and the W grade. These have differing levels
of hydrogenation
from least hydrogenated to most hydrogenated. The E grade has a bromine number
of 15, the R
grade a bromine number of 5, the L grade has a bromine number of 3 and the W
grade a bromine
number of 1. There is also an EastotacTM H-142R resin available. Other useful
tackifying resins
include EscorezTM 1310 LC, an aliphatic hydrocarbon resin, EscorezTM 5300 and
EscorezTM 5400,
partially hydrogenated cycloaliphatic petroleum hydrocarbon resins, and
EscorezTM 5600, a
partially hydrogenated aromatic modified petroleum hydrocarbon resin all
available from Exxon
Chemical Co. in Houston, Tex.; WingtackTM Extra which is an aliphatic,
aromatic petroleum
hydrocarbon resin available from Goodyear Chemical Co. in Akron, Ohio;
HercoliteTM 2100
which is a partially hydrogenated cycloaliphatic petroleum hydrocarbon resin
available from
Hercules in Wilmington, Del; and ZonatacTM 105 Lite which is a styrenated
terpene resin made
from d-limonene and available from Arizona Chemical Co. in Panama City, Fla.
There are numerous types of rosins and modified rosins available with
differing levels of
hydrogenation including gum rosins, wood rosins, tall-oil rosins, distilled
rosins, dimerized rosins
and polymerized rosins. Some specific modified rosins include glycerol and
pentaerythritol esters
of wood rosins and tall-oil rosins. Commercially available grades include, but
are not limited to,
SylvatacTM 1103, a pentaerythritol rosin ester available from Arizona Chemical
Co., UnitacTM R-
100 Lite a pentaerythritol rosin ester from Union Camp in Wayne, N.J.,
ZonesterTM 100, a
glycerol ester of tall oil rosin from Arizona Chemical Co., PermalynTM 305, a
pentaerythritol
modified wood rosin available from Hercules, Inc. in Wilmington, Del. and
ForalTM 105, which is
a highly hydrogenated pentaerythritol rosin ester available. SylvatacTM R-85
which is an 85 C
melt point rosin acid and SylvatacTM 295 which is a 95 C melt point rosin acid
are both available
from Arizona Chemical Co. Fora1TM AX is a 75 C melt point hydrogenated rosin
acid available
from Hercules Inc. NirezTM V-2040 is a phenolic modified terpene resin
available from Arizona
Chemical Co.
There are many available types and grades of tackifying resins available from
many
companies, and one skilled in the art would recognize that this is not an
exclusive list, and that the
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available tackifying resins are too numerous to list here. Various endblock
resins are also useful in
the compositions of the present invention. These include EndexTM 160, an
aromatic hydrocarbon
manufactured by Hercules, Inc. in Wilmington, Del.; KristalexTM 3100 and
KristalexTM 5140,
alphamethyl styrene hydrocarbons manufactured by Hercules, Inc.; and also
coumarone indene
resins. These tackifiers are useful in pressure sensitive adhesives at a level
of from about 0% to
about 65%, preferably from about 10% to about 65%, by weight of the pressure
sensitive
adhesive.
c. Optional Plasticizers
Pressure sensitive adhesives can optionally comprise plasticizers. The
plasticizers useful
in the present pressure sensitive adhesives include, but are not limited to,
mineral based oils and
petroleum based oils, liquid resins, liquid elastomers, polybutene,
polyisobutylene, functionalized
oils such as glycerol trihydroxyoleate and other fatty oils and mixtures
thereof. A plasticizer is
broadly defined as a typically organic composition that can be added to
pressure sensitive
adhesives, such as those that comprise thermoplastics, rubbers and other
resins, to improve
extrudability, flexibility, workability and stretchability in the finished
pressure sensitive adhesive.
Any material which flows at ambient temperatures and is compatible with the
block copolymer
may be useful.
The most commonly used plasticizers are oils which are primarily hydrocarbon
oils that
are low in aromatic content and are paraffinic or naphthenic in character. The
oils are preferably
low in volatility, transparent and have as little color and odor as possible.
This invention also
contemplates the use of olefin oligomers, low molecular weight polymers,
vegetable oils and their
derivatives and similar plasticizing oils.
Examples of useful plasticizers in the present pressure sensitive adhesives
include
Ca1so1TM 5120, a naphthenic petroleum based oil available from Calumet
Lubricants Co. in
Indianapolis, Ind.; KaydolTM White Mineral Oil, a paraffinic mineral oil
available from Witco
Corp. in New York, N.Y.; ParapolTM 1300, a liquid butene homopolymer available
from Exxon
Chemical Co. in Houston, Tex.; IndopolTM H-300, a liquid butene homopolymer,
available from
Amoco Corp. in Chicago, Ill.; EscorezTM 2520, a liquid aromatic petroleum
based hydrocarbon
resin with a pour point of 20 C, available from Exxon Chemical Co.; RegalrezTM
1018, a liquid
hydrogenated aromatic hydrocarbon resin with a pour point of 18 C, available
from Hercules, Inc.
in Chicago, Ill.; and SylvatacTM 5N, a liquid resin of modified rosin ester
with a pour point of
5 C, available from Arizona Chemical Co. in Panama City, Fla. One skilled in
the art would
recognize that any generic 500 second or 1200 second naphthenic process oil
would also be
useful. Plasticizers are useful in the present pressure sensitive adhesives at
levels of from about
0% to about 50% by weight of the pressure sensitive adhesive.
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d. Other Optional Components
Desirable optional components in the present pressure sensitive adhesives
include
diluents, e.g., liquid polybutene or polypropylene, petroleum waxes such as
paraffin and
microcrystalline waxes, polyethylene greases, hydrogenated animal, fish and
vegetable fats,
mineral oil and synthetic waxes such as hydrocarbon oils such as naphthionic
or paraffinic
mineral oils.
Diluents in hot melt adhesives that are solid at ambient temperature, but melt
below
application temperatures are preferred, since these diluents lower the
viscosity on application
resulting in improved distribution and anchoring of the adhesive to the
substrate, while not having
excessive fluidity during use at ambient temperature. Preferably, these resins
have a melting point
between about 35 C and about 200 C, more preferably between about 50 C and
about 150 C.
Other optional components include stabilizers, antioxidants, colorants and
fillers. The
components and amounts of components in the present pressure sensitive
adhesives are selected to
provide the adhesive characteristics desired herein.
A stabilizer or antioxidant can also be used in the pressure sensitive
adhesive. These
compounds can be added to protect the pressure sensitive adhesive from
degradation caused by
reaction with oxygen induced by such things as heat, light or residual
catalyst from other
components of the pressure sensitive adhesive, such as a tackifying resin.
Such antioxidants are
commercially available from Ciba-Geigy in Hawthorne, N.Y. and include
IrganoxTM 565,
IrganoxTM 1010 and IrganoxTM 1076, all hindered phenolic antioxidants. These
are primary
antioxidants which act as free radical scavengers and may be used alone or in
combination with
other antioxidants such as phosphite antioxidants like IrgafosTM 168 available
from Ciba-Geigy.
Phosphite antioxidants are considered secondary antioxidants, are primarily
used as peroxide
decomposers and are generally not used alone, but are instead used in
combination with other
antioxidants. Other available antioxidants are CyanoxTM LTDP, a thioether
antioxidant, available
from Cytec Industries in S! c lhindered phenolic antioxidant,
~ (,Y~S
available from Albemarle ir dants are available for use by
themselves, or in combinat= pounds are added to pressure
sensitive adhesives in sm:.__ ;ht of the pressure sensitive
adhesive, and tend to have no or little effect on the adhesivc characteristics
of the pressure
sensitive adhesive.
Other components that also could be added to pressure sensitive adhesives that
tend to
have no or little effect on the adhesive characteristics are pigments which
add color, fluorescing
agents, any compounds that mask odor and fillers to mention only a few.
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Optional fillers come in the form of particulate matter, fibers and powders,
or may be any
material that does not interfere with the other components in the pressure
sensitive adhesive.
Some examples include calcium carbonate, ceramics, glass, silica, quartz,
mica, treated clay,
titanium dioxide, boron nitrides, graphite, carbon black, metals, barium,
sulfate, talc and mixtures
thereof
e. Adhesive Characteristics of Pressure Sensitive Adhesives
Pressure sensitive adhesives are selected for incorporation in the present
cleaning sheets
based on the adhesive characteristics of the pressure sensitive adhesive,
including Adhesive Work
Value, Tack Value, Cohesive/Adhesive Ratio, and Stringiness Value. These
adhesive
characteristics have been described hereinbefore in Section IV.A.1 and are
measured according to
the Texture Analyzer Method described hereinafter in Section V.A.
Preferred pressure sensitive adhesives typically exhibit an Adhesive Work
Value at 5
grams of pressure of from about 130 to about 1000, preferably from about 160
to about 750, and
more preferably from about 250 to about 650.
In general, the Tack Value at 5 grams of pressure of the pressure sensitive
adhesives is
from about 100 to about 500, preferably from about 150 to about 400, and more
preferably from
about 200 to about 350.
A typical Cohesive/Adhesive Ratio at 5 grams of pressure of the present
pressure
sensitive adhesives is from about 0.2 to about 20, preferably from about 1.0
to about 6.0, and
more preferably from about 3.0 to about 6Ø
The present pressure sensitive adhesives normally have a Stringiness Value at
5 grams of
pressure of from about 2.5 to about 12.0, preferably from about 2.5 to about
8.5, and more
preferably from about 3.0 to about 5Ø
Examples of preferred pressure sensitive adhesives for use in the present
cleaning sheets
herein include, but are not limited to, a series of pressure sensitive
adhesives commercially
available from H.B. Fuller Company under the trade names HL-1496, HM-1597, HM-
1902, HM-
1972, HM-2713, and the like. Other preferred pressure sensitive adhesives
include those available
from the Rohm & Haas Company under the trade names ROBOND PS 75R, ROBOND PS
20,
RHOPLEX VS; ACRONOL DS 3432, and mixtures thereof.
3. Tacky Polvmers
The polymeric additives for incorporation into the present cleaning sheets can
also be
tacky polymers. As used herein, the term "tacky polymers" refers to polymers
that have higher
Tack Values than those typically found in pressure sensitive adhesives, e.g.
polymers having a
Tack Value of at least about 300, preferably at least about 350 (Tack Value is
described in more
detail in Section IV.A.l.b supra). Tacky polymers are also sometimes included
in pressure
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sensitive adhesive compositions as an optional ingredient. In a preferred
embodiment herein, a
tacky polymer is itself a suitable polymeric additive for incorporation in a
cleaning sheet of the
present invention.
Tacky polymers suitable for use as a polymeric additive for the cleaning
sheets herein
include, but are not limited to, polymers selected from the group consisting
of: polyisobutylene
polymers, alkyl methacrylate polymers, polyalkyl acrylates, and mixtures
thereof, wherein the
alkyl groups are CZ-C,g, preferably C2-C12. Preferred tacky polymers are poly
n-decyl
methacrylate, poly ethyl acrylate, poly n-butyl acrylate, and mixtures
thereof. More preferred
tacky polymers herein are polyisobutylene polymers.
Adhesive Characteristics of Tacky Polymers
Tacky polymers are selected for incorporation in the present cleaning sheets
as a
polymeric additive based on the adhesive characteristics of the tacky polymer,
including Adhesive
Work Value, Tack Value, Cohesive/Adhesive Ratio, and Stringiness Value. These
adhesive
characteristics have been described hereinbefore in Section IV.A.1 and are
measured according to
the Texture Analyzer Method described hereinafter in Section V.A. The desired
adhesive
characteristics of tacky polymers can be somewhat different from adhesive
characteristics of
pressure sensitive adhesives due to the differing types of polymeric
additives.
Suitable tacky polymers typically exhibit an Adhesive Work Value at 5 grams of
pressure
of from about 50 to about 1000, preferably from about 75 to about 250, and
more preferably from
about 100 to about 150.
In general, the Tack Value at 5 grams of pressure of the tacky polymers is
from about 300
to about 500, preferably from about 300 to about 450, and more preferably from
about 350 to
about 400.
A typical Cohesive/Adhesive Ratio at 5 grams of pressure of the present tacky
polymers
is from about 0.2 to about 20, preferably from about 1.0 to about 6.0, and
more preferably from
about 3.0 to about 6Ø
The present tacky polymers normally have a Stringiness Value at 5 grams of
pressure of
from about 0.4 to about 12.0, preferably from about 0.8 to about 4, and more
preferably from
about 0.8 to about 2Ø
The tacky polymer additives of the present invention typically have a glass
transition
temperature ("Tg") of at least about -150 C, preferably at least about -100 C,
and more preferably
at least about -80 C. Furthermore, the present tacky polymers typically have a
Tg of no greater
than about 0 C, preferably no greater than about -30 C, and more preferably no
greater than about
-50 C. If the tacky polymer has a Tg that is too high, the tacky polymer tends
to be too viscous
and has poor adhesive characteristics.
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Additionally, the present tacky polymers typically have molecular weight of at
least about
1000, preferably at least about 2500, and more preferably at least about
50,000. Furthermore, the
present tacky polymers typically have a Tg of no greater than about 500,000,
preferably no greater
than about 200,000, and more preferably no greater than about 150,000. If the
molecular weight
of the tacky polymer is too low, the tacky polymer tends to have too low a
viscosity and has
unacceptably low Adhesive Strength and/or Cohesive Strength. Conversely, if
the polymeric
additive has a molecular weight that is too high, the tacky polymer tends to
be too viscous or is a
solid.
Examples of preferred tacky polymers for use in the present cleaning sheets
herein
include, but are not limited to, poly(n hexylmethacrylate); p-2-ethylhexyl
methacrylate;
polyethylacrylate; poly(lauryl acrylate); poly(n butyl acrylate);
polyisobutylene ("PIB"); poly(1,4-
butylene adipate); poly(n decylmethacrylate); poly(octadecylmethacrylate);
poly(lauryl acrylate);
poly(n butyl acrylate); poly(n-decylmethacrylate; and mixtures thereof.
In another embodiment of the invention, preferred pressure sensitive adhesives
have
relatively low Tack Values and Adhesive Work Values under low pressure for
improved hand feel
and glide, but behave similarly to tacky polymers at higher pressures for
improved pick-up. This
recognizes that handling a sheet containing said polymeric additive is
essentially a low pressure
process, while mopping a floor with said sheet containing additive involves
more pressure.
The present pressure sensitive adhesives exhibit an Adhesive Work Value at 5
grams
pressure of from about 30 to 150, preferably from about 40 to about 110, more
preferably from
about 40 to about 80, and exhibit Adhesive Work Value at 15 grams pressure of
from about 50 to
about 1000, preferably from about 75 to about 250, and more preferably from
about 100 to about
150.
In general, the Tack Value of the present pressure sensitive adhesives at 5
grams pressure
is from about 50 to about 600, preferably from about 100 to about 400, and
more preferably form
about 150 to about 300, and exhibit a Tack Value at 15 grams pressure of from
about 300 to about
500, preferably from about 300 to about 450, and more preferably from about
350 to about 400.
A typical Cohesive/Adhesive Ratio of the present pressure sensitive adhesives
at 5 grams
pressure is from about 0.2 to about 20, preferably from about 1.0 to about
6.0, and more
preferably from about 2.0 to about 6.0, and exhibit Cohesive/Adhesive Ratio at
15 grams pressure
of from about 0.1 to about 10, preferably from about 0.2 to about 6.0, and
more preferably from
about 0.2 to about 4Ø
The present pressure sensitive adhesives normally have a Stringiness Value for
both 5
grams pressure and 15 grams pressure of from about 0.4 to about 12.0,
preferably from about 0.8
to about 4, and more preferably from about 0.8 to about 2Ø
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An example of a preferred pressure sensitive adhesive is sold under the trade
name HL
1500, available from H. B. Fuller Company.
The polymeric additives of the present invention are soluble or dispersible in
a variety of
solvents including, but not limited to, water; aromatic hydrocarbons, such as
toluene, xylene,
decahydronaphthalene and tetrahydronaphthalene; aliphatic hydrocarbons
containing from 5 to 11
carbon atoms, such as pentane, hexane, and nonane; chlorinated hydrocarbons,
such as methylene
chloride, carbon tetrachloride, trichloroethylene, perchloroethylene, and
chlorinated aromatic
hydrocarbons such as chlorobenzene; and mixtures thereof.
The amount of polymeric additive impregnated onto the present cleaning sheets
is another
important consideration in obtaining a cleaning sheet that exhibits acceptable
particulate pick-up,
minimal residue, and glide. Typically, the present polymeric additives are
impregnated onto the
present cleaning sheets at a level of polymeric additive of no greater than
about 10.0 g/m',
preferably no greater than about 6.0 g/m2, more preferably no greater than
about 4.0 g/m', and still
more preferably no greater than about 2.0 g/mz. Note that the amount of
polymeric additive
applied to the cleaning sheet does not include the amount of solvent used to
solubilize the
polymeric additive. If the level of polymeric additive is too high, the
cleaning sheet will feel
sticky, resulting in hand feel that is aesthetically unacceptable to household
consumers. Also, if
the level of polymeric additive is too high, the cleaning sheet will not glide
easily across the
surface being cleaned, and will tend to leave a residue on the surface,
resulting in filming and/or
streaking of the surface that is visually unacceptable to consumers. Also, the
present polymeric
additives are typically impregnated onto the present cleaning sheets at a
level of polymeric
additive of at least about 0.1 g/m', preferably at least about 0.2 g/m'-, more
preferably at least
about 0.4 g/mz, and still more preferably at least about 0.6 g/m'. If the
polymeric additive is
impregnated onto the cleaning sheet at a level that is too low, the cleaning
sheet will tend not to
exhibit significantly improved particulate pick-up, with respect to cleaning
sheets that contain no
polymeric additive.
In a preferred embodiment, a polymeric additive is applied to a cleaning sheet
in "zones",
as described hereinafter. The resulting cleaning sheet is then preferably
attached to a cleaning
implement, such as a floor mop as described hereinbefore, having a mop head
containing an
elastic pad, as described hereinbefore, and shown, for example, in Figs. 4, 5,
and 6.
B. Optional Wax and/or Oil Additive
The cleaning performance of any of the cleaning sheets of the present
invention can be
further enhanced by treating the fibers of the sheet, especially surface
treating, with any of a
variety of additives, including surfactants or lubricants, that enhance
adherence of soils to the
sheet. When utilized, such additives are added to the cleaning sheet at a
level sufficient to
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enhance the ability of the sheet to adhere soils. However, the level and type
of additive must be
selected to minimize the amount of residue left on the surface being cleaned
by the cleaning sheet.
Such additives are preferably applied to the cleaning sheet at an add-on level
of at least about
0.01 %, more preferably at least about 0.1 %, more preferably at least about
0.5%, more preferably
at least about 1%, still more preferably at least about 3 %, still more
preferably at least about 4%,
by weight. Typically, the add-on level is from about 0.1 to about 25%, more
preferably from
about 0.5 to about 20%, more preferably from about 1 to about 15%, still more
preferably from
about 2 to about 10%, still more preferably from about 4 to about 8%, and most
preferably from
about 4 to about 6%, by weight of the dry cleaning sheet. The level and type
of additive must be
carefully selected to minimize the residue that is left of the surface wiped
with the present
cleaning sheets to leave the surface visually acceptable to consumers.
A preferred additive is a wax or a mixture of an oil (e.g., mineral oil, etc.)
and a wax.
Suitable waxes include various types of hydrocarbons, as well as esters of
certain fatty acids (e.g.,
saturated triglycerides) and fatty alcohols. They can be derived from natural
sources (i.e., animal,
vegetable or mineral) or can be synthesized. Mixtures of these various waxes
can also be used.
Some representative animal and vegetable waxes that can be used in the present
invention include
beeswax, carnauba, spermaceti, lanolin, shellac wax, candelilla, and the like.
Representative
waxes from mineral sources that can be used in the present invention include
petroleum-based
waxes such as paraffin, petrolatum and microcrystalline wax, and fossil or
earth waxes such as
white ceresine wax, yellow ceresine wax, white ozokerite wax, and the like.
Representative
synthetic waxes that can be used in the present invention include ethylenic
polymers such as
polyethylene wax, chlorinated naphthalenes such as "Halowax," hydrocarbon type
waxes made by
Fischer-Tropsch synthesis, and the like. Other preferred additives are
supplied as mixtures of wax
and oil, such as petrolatum. Such additives can be used by themselves or in
combination with
other wax and oils.
A preferred additive is a mixture of a wax and mineral oil, as it enhances the
ability of the
cleaning sheet to pick up and retain particulate material from surfaces, while
minimizing the
amount of residue left on the surface being wiped with the cleaning sheet.
When a mixture of
mineral oil and wax is utilized, the components will preferably be mixed in a
ratio of oil to wax
of from about 1:99 to about 7:3, more preferably from about 1:99 to about 3:2,
still more
preferably from about 1:99 to about 2:3, by weight. In a particularly
preferred embodiment, the
ratio of oil to wax is about 1:1, by weight, and the additive is applied at an
add-on level of about
5%, by weight. A preferred mixture is a 1:1 mixture of mineral oil and
paraffin wax.
Wax alone, such as paraffin wax, can be utilized as an additive to the present
cleaning
sheets. Where a wax is the only additive, the cleaning sheets are preferably
comprised of
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synthetic fibers, so that the cleaning sheet is still able to maintain
electrostatic properties to
provide enhanced particulate material pick-up and retention. In any event, if
the cleaning sheet
comprises natural and/or synthetic fibers, an additive that consists
essentially of wax is typically
applied to the present cleaning sheets at an add-on level of no greater than
about 4%, preferably
no greater than about 3%, more preferably no greater than about 2%, and even
more preferably
no greater than about 1%, by weight of the cleaning sheet. These levels are
preferred because if a
wax additive is applied to the cleaning sheets at higher levels, the
electrostatic properties of the
sheet will typically be diminished, and therefore decrease the overall
cleaning performance of the
sheet.
Mineral oil alone can also be utilized as an additive to the present cleaning
sheets.
However, if only mineral oil is used, it must be at a relatively low add-on
level in order to
minimize the residue left on surfaces wiped with the cleaning sheet to leave
the surface visually
acceptable to consumers. An additive consisting essentially of mineral oil is
typically applied to
the present cleaning sheets at an add-on level of no greater than about 4%,
preferably no greater
than about 3%, more preferably no greater than about 2%, and even more
preferably no greater
than about 1%, by weight of the cleaning sheet.
These low levels are especially desirable when additives are applied at an
effective level
and preferably in a substantially uniform way to at least one discrete
continuous area of the sheet.
Use of the preferred lower levels, especially of additives that improve
adherence of soil to the
sheet, provides surprisingly good cleaning, dust suppression in the air,
preferred consumer
impressions, especially tactile impressions, and, in addition, the additive
can provide a means for
incorporating and attaching perfumes, pest control ingredients,
antimicrobials, including
fungicides, and a host of other beneficial ingredients, especially those that
are soluble, or
dispersible, in the additive. These benefits are by way of example only. Low
levels of additives
are especially desirable where the additive can leave a visual residue on the
surfaces that are
treated. As a result, the level and type of additive selected are typically
important to enhance the
particulate pick up and retention properties of the cleaning sheet, while
minimizing the amount of
residue left on the surface being wiped with the cleaning sheet.
C. Optional Powder
The present cleaning sheets can also have incorporated therein various types
of powders.
Powders can be desirable to incorporate in the present cleaning sheets,
especially those also
containing polymeric additives, in order to improve the glide characteristics
(i.e. Initial Glide
Value and/or In-Use Glide Value) of the cleaning sheet. Suitable powders for
use herein include,
but are not limited to, those selected from the group consisting of talc,
starch, magnesium
carbonate, and mixtures thereof.
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Powders tend to reduce the tackiness of a cleaning sheet containing polymeric
additive
and/or impart a degree of lubricity to the lower surface of the cleaning
sheet. Suitable powders
typically have a particle size of from about 0.01 to about 250 microns.
Powders having particle
sizes within this range tend to help to reduce friction between the cleaning
sheet and the surface
being cleaned.
Powders are preferably applied to cleaning sheets containing polymeric
additives in
zones, preferably a center zone, as described hereinafter in Section IV.D.
D. Application of Additive to Cleaning Sheet
The application means for these additives preferably applies at least a
substantial amount
of the additive at points on the sheet that are "inside" the sheet structure.
It is an especial
advantage of the three dimensional structures and/or multiple basis weights,
that the amount of
additive that is in contact with the skin and/or surface to be treated, and/or
the package, is limited,
so that materials that would otherwise cause damage, or interfere with the
function of the other
surface, can only cause limited, or no, adverse effects. The presence of the
additive inside the
structure is very beneficial in that soil that adheres inside the structure is
much less likely to be
removed by subsequent wiping action.
Preferably, the additive does not significantly diminish the electrostatic
properties of the
cleaning sheet. It is preferable that the cleaning sheet of the present
invention have electrostatic
properties in order to facilitate pick-up and retention of particulate
material, especially for fine
dust particulate material.
The additive can be applied to the present cleaning sheets via a variety of
application
methods. Such methods include manual rolling, mechanical rolling, slotting,
ultrasonic spraying,
pressurized spraying, pump spraying, dipping, and the like. A preferred method
of application of
the additive to the cleaning sheet is by ultrasonic spraying. The additive can
thus be uniformly
sprayed onto the cleaning sheet.
Another preferred method of application of the additive to the cleaning sheet
is by
mechanical rolling. During the process of making the cleaning sheets, the
sheets are fed through a
set of rollers that are coated with the additive to be applied. The rollers
can be coated with the
additive by rotating in a pan or reservoir containing the additive. As the
sheets are fed through the
rollers, the additive is transferred from the rollers to the cleaning sheets.
If the additive is a
mixture of a wax and mineral oil, particularly in a ratio of wax to mineral
oil of 1:1, the pan or
reservoir containing the additive is preferably heated to a temperature of
from about 32 C to
about 98 C, preferably from about 40 C to about 65 C, in order to maintain the
additive in a
fluid state. In such a situation, the rollers are also preferably heated to a
temperature similar to the
temperature of the hot additive in a fluid state. Typically the temperature of
the additive mix and
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the rollers are maintained at least about 5 C to about 10 C greater than the
melting point of the
additive mixture.
For small scale production of the present cleaning sheets, the additive can
also be applied
to the cleaning sheet via manual rolling, which comprises taking a hand-held
roller, coating the
roller with additive, and rolling the roller across the surface of the
cleaning sheet.
Also important is the amount of surface area of the cleaning sheet that is
covered with the
present additives. The free fibers of the cleaning sheet, in particular
hydroentangled cleaning
sheets or cleaning sheets comprising brushy filaments, are especially
important for small
particulate pick-up. Polymeric additives are particularly important for large
particulate pick-up.
The polymeric additive can be applied either uniformly or non-uniformly across
the surface area
of the present cleaning sheet.
Zoned Application of Additives
When polymeric additives are applied to the cleaning sheets herein, the
resulting cleaning
sheet can have too much tackiness that can result in the sheet having
difficulty gliding across
surfaces, which is unacceptable to consumers. In order to preserve
electrostatic properties of the
cleaning sheet and maintain consumer-acceptable glide values for the cleaning
sheet, the present
polymeric additives can be applied to the cleaning sheet in specific "zones"
of the cleaning sheet,
as opposed to uniformly distributing the polymeric additive across the entire
surface of the
cleaning sheet. In an alternative embodiment, the polymeric additive can be
uniformly distributed
across the entire surface of the cleaning sheet, and an additional additive,
such as a powder and/or
talc as described hereinbefore, can be applied on top of said polymeric
additive, preferably in
specific zones. As used herein, the term "zone" refers to specific portion of
the surface area of a
cleaning sheet.
The polymeric additives are preferably applied to the cleaning sheet in zones,
wherein
each zone can have a different level of polymeric additive in order to
optimize both large
particulate pick-up performance and the ability of the cleaning sheet to
smoothly glide across the
surface, especially when the cleaning sheet is used in conjunction with a
cleaning implement as
described hereinbefore and shown in Figs. 1, 4, 5, and 6.
In a preferred embodiment, the present cleaning sheet has at least two zones
of polymeric
additive, such as a center zone and one or more side zones. As shown in Fig.
29, a center zone 95
comprises an area of the cleaning sheet 99 that spans the length of the
cleaning sheet 99.
However, it should be recognized that the center zone 95 need not span the
entire length of the
cleaning sheet. In addition, although the center zone 95 is preferably
positioned in the relative
center of the cleaning sheet 99, the center zone 95 need not be so positioned.
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The width of the center zone 95 generally depends upon the width of the
cleaning sheet
99 itself. Also, when such a cleaning sheet 99 is used with a cleaning
implement such as a floor
mop 20 as described hereinbefore in Figs. 1, 4, 5, and 6, the width of the
center zone 95 is
preferably dependent upon the width of the contact surface 52 of the elastic
pad 48 of the mop
head 22 of the floor mop 20. In this case, the width of the center zone 95 is
preferably equal to at
least about the width of the contact surface 52, preferably greater than the
width of the contact
surface 52. Typically, the width of the center zone 95 will be equal to from
about 2.5% to about
46%, preferably from about 8.7% to about 35%, and more preferably from about
17.4% to about
23.2%, of the total width of the cleaning sheet 99. In a preferred embodiment,
the cleaning sheet
99 has a total width of about 8.625 inches and the center zone 95 is
positioned in the center of the
cleaning sheet 99 and has a width of from about 0.25 inches to about 4 inches,
preferably from
about 0.75 inches to about 3 inches, and more preferably from about 1.5 inches
to about 2 inches.
The length of the center zone 95 is typically equal to from about 27% to about
100%, preferably
from about 54% to about 97.7%, and more preferably from about 86% to about
95.4%, of the total
length of the cleaning sheet 99. In a preferred embodiment, the cleaning sheet
99 has a total
length of about 11 inches and the center zone 95 has a length of 11 inches
also.
The level of polymeric additive applied in a center zone of a cleaning sheet
as described
herein is typically from about 0.02 g/mz to about 1.5 g/m'', preferably from
about 0.1 g/mZ to
about 1.Og/mZ, and more preferably from about 0.25 g/m'- to about 0.75 g/m2.
The center zone can
also be free of polymeric additive.
The present cleaning sheet can also have zones in addition to a center zone,
such as one or
more side zones. Preferably, the cleaning sheet has two side zones, each
positioned on each side
of the center zone as shown in Fig. 29. The side zones 96 typically span the
length of the
cleaning sheet 99 and have a width that is equal to the distance from the
longitudinal edge 97 of
the center zone to the longitudinal edge 98 of the cleaning sheet. However, it
should be
recognized that a side zone 96 need not span the total length of the cleaning
sheet 99 and need not
have a width that is equal to the distance from the longitudinal edge 97 of
the center zone to the
longitudinal edge 98 of the cleaning sheet.
The width of a side zone 96 generally depends upon the width of the cleaning
sheet 99
itself. Also, when such a cleaning sheet 99 is used with a cleaning implement
such as a floor mop
20 as described hereinbefore in Figs. 1, 4, 5, and 6, the width of a side zone
95 is preferably
dependent upon the distance between the longitudinal edge 97 of the center
zone and the
longitudinal edge 98 of the point at which the cleaning sheet is folded over
top of the mop head
22 of the floor mop 20. In this case, the width of the center zone 95 is
preferably equal to at least
about the distance between the longitudinal edge 97 of the center zone and the
longitudinal edge
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of the point at which the cleaning sheet is folded over top of the mop head 22
of the floor mop 20
in order to be attached to the mop head 22. Typically, the width of a side
zone 96 will be equal to
from about 2.5% to about 46%, preferably from about 5.8% to about 35%, and
more preferably
from about 11.6% to about 23.2%, of the total width of the cleaning sheet 99.
In a preferred
embodiment, the cleaning sheet 99 has a total width of about 8.625 inches, a
center zone 95
positioned in the center of the cleaning sheet that has a width of from about
0.25 inches to about 4
inches, preferably from about 0.75 inches to about 3 inches, and more
preferably from about 1.5
inches to about 2 inches, and two side zones 96, with each side zone 96 having
a width of from
about 0.25 inches to about 4 inches, preferably from about 0.5 inches to about
3 inches, and more
preferably from about 1 inch to about 2 inches. The length of each side zone
96 is typically equal
to from about 27% to about 100%, preferably from about 54% to about 97.7%, and
more
preferably from about 86% to about 95.4%, of the total length of the cleaning
sheet 99. In a
preferred embodiment, the cleaning sheet 99 has a total length of about 11
inches and each side
zone 96 has a length of 11 inches also.
The level of polymeric additive applied in a side zone of a cleaning sheet as
described
herein is typically from about 0.1 g/mz to about 5.0 g/mz, preferably from
about 0.5 g/m' to about
3.0g/m2, and more preferably from about 1.0 g/mz to about 2.0 g/mZ.
A cleaning sheet that has both a center zone and one or more side zones,
typically
contains a polymeric additive that has a Coating Concentration Differential of
from about 1% to
about 90%, preferably from about 10% to about 60%, and more preferably from
about 25% to
about 40%; wherein the Coating Concentration Differential is calculated
according to the
following formula:
(level of additive in center zone (g/m2)) / (level of additive in side zone
(g/m2)) x 100%
In an alternative embodiment, the present cleaning sheets can have a polymeric
additive
that is uniformly distributed across at least one surface, or both surfaces,
of the cleaning sheet. In
this preferred embodiment, the optional powders as described hereinbefore can
be applied in a
center zone, as described hereinbefore, of the cleaning sheet in order to
reduce the tackiness and
improving glide of the cleaning sheet, while retaining the ability of the
cleaning sheet to pick-up
large particulate material from the surface being cleaned. In this embodiment,
the powder is
applied to the center zone of the cleaning sheet at a level of from about 0.1
g/m'' to about 5.0 g/mZ,
preferably from about 0.5 g/mz to about 3.0 g/mz, and more preferably from
about 1.0 g/mz to
about 2.0 g/mz.
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The cleaning sheets of the present invention containing the present additives
exhibit
consumer-acceptable particulate pick-up, filming and/or streaking, and glide
when used to clean
household surfaces, especially kitchen and/or bathroom floors such as ceramic
tile, vinyl tile,
linoleum, hardwood floors, and the like.
When cleaning surfaces with the present cleaning sheets, it is important to
have the ability
to pick-up both large and small particulate material. Test methods for
measuring small particulate
material is described in section V.B, infra, and for measuring large
particulate material is
described in section V.C, infra. Preferably, the present cleaning sheets
exhibit small particulate
pick-up of at least about 35%, preferably at least about 45%, more preferably
at least about 55%,
and still more preferably at least about 60%, by weight of the small
particulate material originally
present on the surface. In addition, the present cleaning sheets preferably
exhibit large particulate,
wherein the large particulate soil is sand, pick-up of at least about 20%,
preferably at least about
30%, more preferably at least about 40%, and still more preferably at least
about 50%, by weight
of the large particulate material originally present on the surface. The
present cleaning sheets
preferably exhibit large particulate, wherein the large particulate soil is
mulch, pick-up of at least
about 40%, preferably at least about 60%, more preferably at least about 70%,
and still more
preferably at least about 80%, by weight of the large particulate material
originally present on the
surface.
In addition, the Initial Glide Value and In-Use Glide Value of the cleaning
sheet should
be minimized to allow the cleaning to smoothly glide across the surface being
cleaned. If the
Initial Glide Value and/or In-Use Glide Value is too high, a consumer will
have a difficult time in
smoothly moving the cleaning sheet back and forth across the surface being
cleaned. Preferably,
the present cleaning sheets will have an Initial Glide Value of no greater
than about 3.5,
preferably no greater than about 2.0, more preferably no greater than about
1.5, and still more
preferably no greater than about 1Ø Preferably, the present cleaning sheet
will have an In-Use
Glide Value of no greater than about 2.5, preferably no greater than about
1.5, more preferably no
greater than about 1.0, and still more preferably no greater than about 0.5.
Initial Glide Value and
In-Use Glide Value is determined according to the Test Method described herein
in section V.D,
infra.
V. Test Methods
A. Texture Analyzer Method
The adhesive characteristics of Tack Value, Adhesive Work Value, Cohesive/
Adhesive
Ratio, and Stringiness Value, as described in Section IV.A.3 supra, are
measured according to the
following test method. A texture analyzer is used to measure the adhesive
characteristics of a
given additive as described herein. A texture analyzer is commercially
available from Stable
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Micro Systems, Ltd. in Godalming, Surrey UK under the trade name TA.XT2
Texture Analyser.
The TA.XT2 Texture Analyser is shown in FIG. 27 and incorporates the following
features:
instrument probe arm 101; stationary plate 102; acrylic probe 103, which is
preferably a 1.5 inch
diameter acrylic probe; probe attachment 104; sample holder 105; sliding stand
106; displacement
transducer 107; control unit 108; and personal computer 109. The personal
computer 109 (e.g.
IBM PC) that is part of the TA.XT2 Texture Analyzer runs Texture Expert for
Windows
Software. The Texture Expert for Windows Software automatically calculates
Tack Value,
Adhesive Work Value, Cohesive/ Adhesive Ratio, and Stringiness Value, as
described in Section
IV.A.3 supra.
A sample polymeric additive is analyzed using the TA.XT2 Texture Analyzer
according
to the following procedure. A sample is prepared in a 5cm diameter sample
holder 105 at a depth
of 1.5 to 1.75mm. If the sample is a hot melt, the correct number of grams are
placed in the
sample holder 105, melted, and allowed to cool. If the sample is dissolved in
solvent, the correct
amount is calculated based on % solids, added to the sample holder 105, and
allowed to dry
completely. The TA.XT2 Texture Analyser is calibrated according to the
instruction manual
before use. The acrylic probe 103 (e.g. 1.5" diameter domed acrylic probe) to
be used is cleaned
and securely attached to the Texture Analyzer via the probe attachment 104.
The settings of the
TA.XT2 Texture Analyser are adjusted to the following levels:
Pre-speed: 2mm/s
Post-speed: 2mm/s
Trigger: 5.0 - 20.0 grams
Test time: 5 seconds
The Trigger is the initial downward pressure exerted on the sample by the
acrylic probe. The
sample holder 105 is held firmly in place while the acrylic probe 103 is
lowered to contact the
sample and the raised again to the starting position by the machine. A graph
of the test results is
generated by the personal computer 109 and the results are calculated from the
graph.
B. Small Particulate Pick-up Performance Test
The ability of a cleaning sheet to pick-up particulate material from a surface
is measured
according to the following test method. This test method is performed by
carrying out the
following steps:
1. A soil is prepared to simulate the particulate material that is typically
found on
household surfaces. The soil used in this test method consists of the
following: 0.50
g of vacuum cleaner soil (i.e. dirt collected from vacuum cleaner bags), 0.50
g of
fluffy soil (composed of a 50/50 mix of finely shredded cellulose and vacuum
cleaner soil), and 0.02 g of pet hair.
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2. A vinyl flooring test surface area, which is approximately 1.5 meters x 21
meters, is
then prepared for testing by pre-cleaning the vinyl flooring with a 20%
isopropanol
solution and buffing the surface of the vinyl flooring dry. After the surface
is dry,
clean the surface with a commerical Swiffer' implement and clean Swiffer'
sheet to
standardize the electrostatic charge on the surface.
3. The soil (described above) is weighed and then dispersed evenly across the
surface of
the pre-cleaned vinyl flooring within the test surface area of approximately
1.5
meters x 21 meters.
4. A cleaning sheet to be tested is weighed and then placed on an implement
with mop
handle and pad, such as a Swifferl~ implement. The surface of the vinyl
flooring is
then cleaned in the following pattern: Floor is swept using an up and down S -
pattern. The first two thirds of the width of the floor is cleaned starting on
the left
front side and ending on the right two/thirds side. Halfway through the cycle,
the
mophead should be swiveled to change the leading edge from the front to the
back
(i.e. Flip Step). After switching the leading/trailing edge, soil may fall off
the sheet.
If this is the case the mop is run over the soil that has fallen off. Then,
the floor is
swept, continuing to follow the up and down S - pattern. Once the end of the
surface
is reached, push the mop straight forward until you come to the right back
corner of
the testing surface. Turn the mop head to the left and continue pushing across
the
back of the baseboard, cleaning the back one-thirds. Once the corner is
reached, turn
mop head to the left, and push it across the length of the flooring. Once the
end of
the surface is reached, turn mop head to the right and bring soil pile to the
middle of
the flooring. This cleaning pattern is depicted as follows:
a a a a a a a a a a
E* b ~ b b b 4
END/STAMP a a a 4
4 b tT b 4 b 4 b 4 b 4
4 b 4 b 4 b 4 b 4 b 4
4 ~ &
T
START * FLIP STEP
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6. After Steps 1 and 2 have been completed, pick-up the mop head off the floor
and
carefully place it directly on top of the soil pile. With moderate pressure,
push down on
the soil pile and lift (i.e. Stamp).
7. Re-weigh the cleaning sheet on an analytical balance and record sheet
weight.
8. Data is calculated and reported using the following formula:
% Sheet Pickup = (Final Sheet Weight - Initial Sheet Weight) / (Soil Weight) x
100
The test method is replicated 3 times, the results are averaged, and are
reported as
"SMALL PARTICULATE PICK-UP".
C. Large Particulate Pick-Up Performance Test
This test comprises the measuring of pick-up of different large particle
soils, each
weighed separately. Each soil is weighed separately in plastic weigh boats
using an analytical
balance. Although a variety of large particle soils can be used, the following
soil types and
amounts can be used:
(1) 1.5g of sand (e.g. "Quikrete Sand), sifted to 710um-1.19mm;
(2) 1.0 g of mulch (Ohio Mulch Black Gold Mulch), spread on tray and tried in
a fume
hood for one day, and in a dessicator for one day, sifted to 710um-6.3 nzin;
(3) 0.75g of Froot Loops Cereal, crushed and sifted to 2.0-4.0 mm; or
(4) 2.0 g Combination Soil, composed of 0.5g sand, 0.5g mulch, 0.5g Cereal,
and 0.5 g
Vacuum cleaner soil (i.e. dirt collected from vacuum cleaner bags).
Floor Preparation
A 6' x 3' section of vinyl flooring (e.g. Armstrong Signia Collection
Flooring) is cleaned by
wiping the entire surface with a 20% isopropyl alcohol solution and a paper
towel. Before the soil
is distributed, the surface is dried. The soil is spread evenly over the
surface of the flooring by
dispensing it directly from the weigh boat. Only one soil type of the
appropriate weight is applied
for each test (except in the case of the aforementioned combination soil). If
performance for each
soil type is desired, separate tests are performed.
General Procedure (see dia r~ am)
1. Once the floor is prepared for the test, weigh the sheet to be tested by
placing it in a tared
glass beaker on the analytical balance and record the weight. Place the sheet
on the
appropriate mop head (attached to the handle) and begin by placing the mop
head in the
lower left corner of the 6'x3' floor, standing at a 3' end.
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2. Pushing the mop ahead using Edge A as the leading edge (see diagram), sweep
along the
edge of the floor until reaching the opposite end.
3. Stop, slide the mop to the right approximately six inches without turning
it, and using Edge
B as the leading edge, pull it back in a straight line down the floor to the
3' end where
mopping started.
4. Stop, slide the mop to the right six inches, and push it ahead again in a
straight line to the
opposite end of the floor. This process should be repeated until five passes
have been made
across the floor. The mop should end up in the upper right corner of the
floor, compared to
where the test started.
5. Keeping the mop in contact with the floor, stand in the upper left corner,
turn the mop 90 to
the left, and sweep the perimeter of the floor by pulling the mop towards the
upper left
corner, turning it at the corner, and pushing it ahead the rest of the way
around the perimeter
of the floor.
6. After mopping, carefully pick up the mop so that as little soil as possible
falls from the
sheet. Carefully fold the sheet with the soil inside and weight it again in
the tared beaker on
the same analytical balance.
7. Sweep the remaining soil from the floor using a brush or a vacuum cleaner
before
performing the next test. Wipe the floor clean with 20% IPA solution.
8. In order to get an accurate result, repeat each test with the same sheet or
mop head being
tested three to six times and take the average
Diagram
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c> End
4 b 4 4
4 b 4 Q
4 b 4 4
4 ~ 4 b 4
4 ~ 4 b 4
tart ~~ ~
CALCULATIONS
The large particulate pick-up is calculated using the following formula:
% Sheet Pickup = (Final Sheet Weight - Initial Sheet Weight) / (Soil Weight) x
100
The results of this test method (being an average of 3 replications) are shown
below in
Table 2 under the column heading "LARGE PARTICULATE PICK-UP".
D. Glide Value
The following test method is used to derive two quantitative grades that
reflect the ability
of the cleaning sheet to glide smoothly and easily across a surface being
cleaned. Initial Glide
Value and In-Use Glide Value are measured according to this test method.
Initial Glide Value of a cleaning sheet is measured as follows. A cleaning
sheet is placed
securely on the mop head of a cleaning implement such as a floor mop. The
floor mop is put
down on vinyl flooring (e.g. Armstrong Signia Collection Flooring), which has
been cleaned by
wiping the entire surface of the vinyl flooring with a 20% isopropyl alcohol
solution and a paper
towel, in the area where sweeping begins. To begin sweeping, the floor mop is
pushed forward
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across the surface of the vinyl flooring. The operator then quantitatively
assess the degree to
which the floor mop and cleaning sheet resists movement across the surface of
the flooring, as
well as the effort involved in moving the floor mop across the surface of the
flooring from the
initial starting point.
In-Use Glide Value of a cleaning sheet is measured as follows. During the
sweeping
motion there can be resistance to the mopping motion, or drag, as the floor
mop and cleaning
sheet move across the surface of the flooring. The operator then
quantitatively assess the degree
of resistance to the glide of the mop as it passes over the surface of the
flooring, as well as when
sweeping starts and stops during the procedure (as in the end of one pass and
beginning of the
next).
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The following Grading Scale is used by the operator to quantify the glide
values. For each
of the two glide assessments described above, there is a grade given for that
sheet or type of
coating. The scale is 0 to 8 with whole number or half grades given. The
following are the
guidelines to use in the assessments.
Grade Initial Glide Value In-Use Glide Value
no initial resistance no resistance to glide
0 noticed; little effort while mopping
required to move mop
light to moderate light resistance to
2 resistance; some effort glide noticed while
required to move mop mo in
moderate to heavy moderate resistance
4 resistance; moderate to glide noticed while
effort required to move mopping
the mop
very heavy resistance; heavy resistance to
6 difficult to move the glide noticed while
mop
from starting position mo in
extreme resistance; extreme resistance to
8 impossible to move the glide; impossible to
mop from the starting move mop smoothly
osition across the floor
The following are non-limiting examples of the cleaning sheets and polymeric
additives
of the present invention.
EXAMPLE IA
This Example shows the adhesive characteristics of a variety of polymeric
additives of the
present invention. The adhesive characteristics of each polymeric additive are
measured according
to the Texture Analyzer Test Method described hereinbefore in Section V.A with
a pressure (i.e.
Trigger) of 5.0 grams. The adhesive characteristics measured and/or reported
include Tack Value,
Adhesive Work Value, Cohesive/Adhesive Ratio, and Stringiness Value, and are
reported in the
following Table 1 A.
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TABLE lA
Adhesive Cohesive/Adhesive Stringiness
Polymeric Additive Tack Value Work Value Ratio Value
HL-14961 254 298 4.89 8.14
HL-1597a 154 206 3.72 3.82
HL-1902a 215 304 0.42 3.87
HL-1972a 287 219 1.77 2.71
HL-2713a 296 508 5.05 5.17
ROBOND PS75Rb 178 498 0.27 6.27
PIB 85,000' 327 71 0.16 0.9
a Pressure sensitive adhesive commerically available from H.B. Fuller Company.
b Pressure sensitive adhesive commercially available from Rohm & Haas Company.
' Polyisobutylene tacky polymer having a molecular weight of about 85,000.
EXAMPLE IB
This Example shows the effect of increased pressure (i.e. Trigger) on the
adhesive
characteristics of a pressure sensitive adhesive sold under the trade name HL
1500 by the H B.
Fuller Company. The adhesive characteristics are measured according to the
Texture Analyzer
Test Method described in Section V.A. with varying pressures (i.e. Trigger) as
indicated in Table
1B. The adhesive characteristics measured include Tack Value, Adhesive Work
Value,
Cohesive/Adhesive Ratio, and Stringiness Value, and are reported in the
following Table 1B.
TABLE 1B
Polymeric Trigger Adhesive Cohesive/Adhesi Stringiness
Additive rams Tack Value Work Value ve Ratio Value
HL 1500 5.0 239 60 1.54 0.84
HL 1500 10.0 252 84 1.66 1.02
HL 1500 15.0 392 137 0.49 1.06
HL 1500 20.0 390 152 0.29 1.12
EXAMPLE II
The following "Example Sheet A" exemplifies a heat-bonded cleaning sheet of
the
present invention, which contains a polymeric additive. Tables 2A and 2B
provide the results of
the Large Particulate Pick-up Performance Test (described in Section V.C.
supra) and the Glide
Value test method (described in Section V.D. supra) for the exemplified
cleaning sheet containing
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a polymeric additive (as specified in Tables 2A and 2B), with the cleaning
sheet being attached to
a cleaning implement comprising a mop head with an elastic pad as described
hereinbefore and
shown in Figs. 1, 4, 5, and 6. For the results shown in Table 2A, the
polymeric additive is first
dispersed or dissolved in a solvent, then the solution or dispersion is
sprayed onto Example Sheet
A, and the solvent is allowed to evaporate. For the results shown in Table 2B,
the polymeric
additive is applied to Example Sheet A via a hot melt spray.
EXAMPLE SHEET A
This example describes a process of making a cleaning sheet as illustrated by
the diagram
of Fig. 24. During this process, a continuous first web 310 made of
polypropylene having a width
of 210mm and a basis weight of 30g/mz is continuously fed from left to right
as viewed in the
diagram. Simultaneously, a tow 312 comprising a bundle of 2,000 - 100,000
polyester continuous
filaments 315 each of 2 - 30 deniers is continuously fed from left to right as
viewed in the
diagram. The tow 312 is opened or fibrillated by a set of expanding rolls 311
to form a continuous
second web having a desired width and thereafter placed upon the first web
310. The first web
310 and the second web 312 are transported to a heating emboss machine 313 in
which they are
compressed together under heating and integrally heat-sealed along thereby
formed heat seal lines
316 transversely extending to form a continuous composite third web 314. The
heat-seal lines 316
are provided so as to be spaced apart one from another by a distance d as
measured longitudinally
on the third web, i.e., intermittently arranged longitudinally on the third
web 314. Thereafter, the
second web 312 is cut by a first cutter 317 along a middle line extending
parallel to and between
each pair of adjacent heat-seal lines 316 in two, thereby forming tufts of
brushy filaments
extending outwardly from the overall structure. Then, the first web 310 is cut
by a second cutter
318 into a desired length. In this manner, the individual cleaning sheets 1
are obtained from the
third web 314. In this process, the individual basic sheets 10 are obtained
from the first web 310,
the brushy filaments are obtained from the second web 312, the individual
filaments 15 of the
brushy filaments are obtained from the continuous filaments 315 and the
anchoring portions 16
are provided by the heat-seal lines 316. Preferably, each of the heat-seal
lines 316 has a width of 2
- 10mm and is spaced apart from the adjacent heat-seal line by a distance d of
20 - 200mm. The
brushy filaments or the second web or the tow 312 prior to formation of these
brushy filaments
are coated with a polymeric additive of the present invention as described in
Table 2 at an
appropriate step of the process. In a section of the first web 310 to be cut
by the second cutter 318,
a distance D between each pair of adjacent heat-seal lines 316 may be
dimensioned to be longer
than the distance d to obtain a relatively large marginal region 7
facilitating the cleaning sheet 1 to
be mounted on the holder 2. In this case, the section defined between two
adjacent heat-seal lines
spaced from each other by the distance D necessarily provides relatively long
brushy filaments
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and these brushy filaments must be cut to a length in conformity of the
remainder brushy
filaments. According to the process illustrated, a length of each filament 15
hanging down from
the anchoring portion 16 corresponds to 1/2 of the distance d. If desired, a
length of the second
web 312 fed on the section of the first web 310 defined between each pair of
adjacent heat-seal
lines 316 may be dimensioned to be longer than the distance d in order to
obtain the filaments 15
longer than 1/2 of the distance d.
A cleaning sheet resulting from this process is shown in Fig. 23.
TABLE 2A
Large Particulate Pick-Up Glide Value
Froot
Polymeric Level Sand Mulch LoopsTM Combination
Additive (g/mZl Soil Soil Soil Soil Initial In-Use
HL-1496a 1.12- 47% 93% 69% 55% 2.125 2
1.56
HM-1597a 1.12- 69% 86% 79% 71% 2.875 2.125
1.56
HM-1902a 1.12- 78% 96% 87% 68% 3 2.375
1.56
HM-1972a 1.12- 32% 93% 81% 53% 1.25 1
1.56
HM-2713a 1.12- 60% 93% 82% 59% 1.375 0.625
1.56
ROBOND 1.12- 68% 88% 82% 58% 2.375 1.25
PS75Rb 1.56
a Pressure sensitive adhesive commerically available from H.B. Fuller Company,
which is applied
to Example Sheet A via a toluene solution spray.
b Pressure sensitive adhesive commercially available from Rohm & Haas Company,
which is
applied to Example Sheet A via an aqueous dispersion spray.
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TABLE 2B
Lar2e Particulate Pick-Up Glide Value
Froot
Polymeric Level Sand Mulch LoopsTM
Additive (g/mZl Soil Soil Soil Initial In-Use
HL-2713a 0.4 21 74 60 0.6 0.7
0.6 28 92 81 0.9 0.9
0.8 22 86 76 1.9 1.0
1.0 24 81 77 2.3 1.1
HL-1500a 0.6 25 87 61 0.5 0.5
0.8 38 88 77 0.8 0.8
1.0 25 88 77 0.9 0.6
a Pressure sensitive adhesive commerically available from H.B. Fuller Company,
which is applied
to Example Sheet A via a hot melt spray.
