Note: Descriptions are shown in the official language in which they were submitted.
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WO 2004/099501 PCT/US2004/012584
SOFT FIBROUS STRUCTURE
FIELD OF THE INVENTION
The present invention relates to fibrous structures, especially to through-air-
dried fibrous
structures, that exhibit a Slip Stick Coefficient of Friction of less than
about 0.023 and a B
Compressibility of from about 15 to about 50 and/or fibrous structures,
especially through-air-
dried fibrous structures, which exhibit a Slip Stick Coefficient of Friction
of less than about
0.0175.
BACKGROUND OF THE INVENTION
It is well known in the art that the softness of a fibrous structure or a
sanitary tissue
product, especially a through-air-dried sanitary tissue product, incorporating
a fibrous structure is
inversely proportional to the total tensile strength of the fibrous structure
or sanitary tissue
product. Further, it is well known in the art that the smoothness of a fibrous
structure or a
sanitary tissue product, especially a through-air-dried sanitary tissue
product, incorporating a
fibrous structure is inversely proportional to the caliper of the fibrous
structure or sanitary tissue
product.
Attempts by formulators to overcome the inverse relationships, especially the
softness to
total tensile strength have included adding cationic silicones to sanitary
tissue products and/or
fibrous structures making up such products. See for example U.S. Patent No.
5,059,282 to
Ampulski et al.
Formulators have deposited various softening agents, including silicone
materials, onto
the external surfaces of fibrous structures to try to deliver the consumer
desired softness and/or
smoothness. Such prior art fibrous structures exhibited Coefficients of
Friction of about 0.72 to
about 1.07 or Slip Stick Coefficients of Friction of from at least about
0.0207 or B
Compressibility of less than or equal to 17.
Prior formulators have failed to develop a fibrous structure, especially a
through-air-dried
fibrous structure, which exhibits a Slip Stick Coefficient of Friction of less
than about 0.023 and a
B Compressibility of from about 15 to about 50 and/or fibrous structures,
especially through-air-
dried fibrous structures, which exhibit a Slip Stick Coefficient of Friction
of less than about
0.0175. Accordingly, there exists a long felt need to provide a fibrous
structure, especially
a through-air-dried fibrous structure, that exhibits a Slip Stick Coefficient
of Friction of less than
about 0.023 and a B Compressibility of from about 15 to about 50 and/or
fibrous structures,
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WO 2004/099501 PCT/US2004/012584
especially through-air-dried fibrous structures, that exhibit a Slip Stick
Coefficient of Friction of
less than about 0.0175.
SUMMARY OF THE INVENTION
The present invention fulfills the need described above by providing a fibrous
structure,
especially a through-air-dried fibrous structure, which exhibits a Slip Stick
Coefficient of Friction
of less than about 0.023 and, optionally, a B Compressibility of from about 15
to about 50.
In one aspect of the present invention, a fibrous structure that exhibits a
Slip Stick
Coefficient of Friction of less than about 0.023 and/or less than about 0.021
and/or less than about
0.0190 and/or less than about 0.0175 is provided.
In another aspect of the present invention, a fibrous structure that exhibits
a Slip Stick
Coefficient of Friction of less than about 0.023 and a B Compressibility of
from about 15 to about
50.
In yet another aspect of the present invention, a single- or multi-ply
sanitary tissue
product comprising a fibrous structure according to the present invention is
provided.
Accordingly, the present invention provides a fibrous structure that exhibits
a Slip Stick
Coefficient of Friction of less than about 0.023, a fibrous structure that
exhibits a Slip Stick
Coefficient of Friction of less than about 0.023 and a B Compressibility of
from about 15 to about
50, and a single- or multi-ply sanitary tissue product comprising a fibrous
structure according to
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
"Fiber" as used herein means an elongate particulate having an apparent length
greatly
exceeding its apparent width, i.e. a length to diameter ratio of at least
about 10. More specifically,
as used herein, "fiber" refers to papermaking fibers. The present invention
contemplates the use
of a variety of papermaking fibers, such as, for example, natural fibers or
synthetic fibers, or any
other suitable fibers, and any combination thereof. Papermaking fibers useful
in the present
invention include cellulosic fibers commonly known as wood pulp fibers.
Applicable wood pulps
include chemical pulps, such as Kraft, especially Northern Softwood Kraft
("NSK"), sulfite, and
sulfate pulps, as well as mechanical pulps including, for example, groundwood,
thermomechanical pulp and chemically modified thermomechanical pulp.
Nonlimiting examples
of wood pulps include fibers derived from a fiber source selected from the
group consisting of
Acacia, Eucalyptus, Maple, Oak, Aspen, Birch, Cottonwood, Alder, Ash, Cherry,
Elm, Hickory,
Poplar, Gum, Walnut, Locust, Sycamore, Beech, Catalpa, Sassafras, Gmelina,
Albizia,
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CA 02523571 2007-08-15
Anthocephalus, Magnolia, Bagasse, Flax, Hemp, Kenaf and mixtures thereof.
Chemical pulps,
however, may be preferred since they impart a superior tactile sense of
softness to tissue sheets
made therefrom. Pulps derived from both deciduous trees (hereinafter, also
referred to as
"hardwood"), especially tropical hardwood, and coniferous trees (hereinafter,
also referred to as
"softwood") may be utilized. The hardwood and softwood fibers can be blended,
or alternatively,
can be deposited in layers to provide a stratified web. U.S. Pat. No.
4,300,981 and U.S. Pat. No.
3,994,771. for the purpose of disclosing layering of hardwood
and softwood fibers. Also applicable to the present invention are fibers
derived from recycled
paper, which may contain any or all of the above categories as well as other
non-fibrous materials
such as fillers and adhesives used to facilitate the original papermaking.
In addition to the various wood pulp fibers, other cellulosic fibers such as
cotton linters,
rayon, and bagasse can be used in this invention. Synthetic fibers, such as
polymeric fibers, can
also be used. Elastomeric polymers, polypropylene, polyethylene, polyester,
polyolefin, and
nylon, can be used. The polymeric fibers can be produced by spunbond
processes, meltblown
processes, and other suitable methods known in the art. One exemplary
polyethylene fiber that
can be utilized is Pulpexe, available from Hercules, Inc. (Wilmington, Del.).
In addition to the above, fibers and/or filaments made from polymers,
specifically
hydroxyl polymers may be used in the present invention. Nonlimiting examples
of suitable
hydroxyl polymers include polyvinyl alcohol, starch, starch derivatives,
chitosan, chitosan
derivatives, cellulose derivatives, gums, arabinans, galactans and mixtures
thereof.
An embryonic fibrous web can be typically prepared from an aqueous dispersion
of
papermaking fibers, though dispersions in liquids other than water can be
used. The fibers can be
dispersed in the carrier liquid to have a consistency of from about 0.1% to
about 0.3%. It is
believed that the present invention can also be applicable to moist forming
operations where the
fibers are dispersed in a carrier liquid to have a consistency less than about
50%, more preferably
less than about 10%.
"Sanitary tissue product" as used herein means a soft, low density (i.e., <
about 0.15
g/cm) web useful as a wiping implement for post-urinary and post-bowel
movement cleaning
(toilet tissue), for otorhinolaryngological discharges (facial tissue and/or
hankies), and multi-
functional absorbent and cleaning uses (absorbent towels). The properties and
values thereof
discussed herein with respect to the fibrous structures described herein may
also be present in the
sanitary tissue products incorporating such fibrous structures.
"Weight average molecular weight" as used herein means the weight average
molecular
weight as determined using gel permeation chromatography according to the
protocol found in
. 3
CA 02523571 2007-08-15
Colloids and Surfaces A. Physico Chemical & Engineering Aspects, Vol. 162,
2000, pg. 107-
121.
"Ply" or 'Plies" as used herein means an individual fibrous structure
optionally to be
disposed in a substantially contiguous, face-to-face relationship with other
plies, forming a
multiple ply fibrous structure. It is also contemplated that a single fibrous
structure can
effectively form two "plies" or multiple "plies", for example, by being folded
on itself.
"Caliper" as used herein means the macroscopic thickness of a sample. Caliper
of a
sample of fibrous structure and/or sanitary tissue product according to the
present invention are
obtained on a VIR Electronic Thickness Tester Model 11 available from Thwing-
Albert
Instrument Company, Philadelphia, PA. The caliper measurement can be repeated
and recorded
at least five (5) times so that an average caliper can be calculated. The
result is reported in
millimeters.
"Smoothness" and/or "Physiological Surface Smoothness" as used herein is a
factor
(hereinafter the PSS Factor and/or SMD Factor) derived from scanning machine-
direction fibrous
structure and/or sanitary tissue product samples with a profilometer having a
diamond stylus, the
profilometer being installed in a surface test apparatus such as, for example,
is described in the
1991 International paper Physics Conference. TAPPI Book 1, article entitled
"Methods for the
Measurement of the Mechanical Properties of Tissue Paper" by Ampulski et al.
found at page 19,
and/or in U.S. Pat. No, 5,059,282 issued to Ampulski et al.
The smoothness and/or the inverse of smoothness (i.e., roughness) can also be
measured using a Kato Surface Tester KES-FB4 which is available from Kato
Tekko Co., LTD.,
Karato-Cho, Nishikiyo, Minami-Ku, Koyota, Japan. Alternatively, the smoothness
of a fibrous
structure and/or sanitary tissue product according to the present invention
may be measured using
a Primos Optical Profiler/3D Surface Analyzer commercially available from GF
Messtechnik,
Berlin, Germany. It is desirable that fibrous structures and/or sanitary
tissue products comprising
such fibrous structures exhibit a smoothness of greater than about 500 and/or
from about 500 to
about 1200 and/or from about 550 to about 1000 and/or from about 600 to about
950 and/or from
about 650 to about 900.
"Slip Stick Coefficient of Friction" (S&S COF) is defined as the mean
deviation of the
coefficient of friction. Like the coefficient of friction, it is
dimensionless. This test is performed
on a KES-FB4 Surface Analyzer from Kato Tekko Co. with a modified friction
probe. The probe
sled is a two centimeter diameter, 40 to 60 micron glass frit obtained from
Ace Glass Company.
The normal force of the probe was 19.6 grams. The details of the procedure are
described in
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CA 02523571 2007-08-15
"Methods for the Measurement of the Mechanical Properties of Tissue Paper" by
Ampulski, et.
al., 1991 International Paper Physics Conference, page 19.
In one embodiment, the fibrous structure exhibits a Slip Stick Coefficient of
Friction of
from about 0.010 to about 0.021 and/or from about 0.0135 to about 0.0190
and/or from about
0.0135 to about 0.0175.
"Total Dry Tensile Strength" or "TDT" of a fibrous structure and/or sanitary
tissue
product comprising such fibrous structure is measured as follows. One (1) inch
by five (5) inch
(2.5 cm X 12.7 cm) strips of fibrous structure and/or paper product comprising
such fibrous
structure are provided. The strip is placed on an electronic tensile tester
Model 1122
commercially available from Instron Corp., Canton, Massachusetts in a
conditioned room at a
temperature of 73 F 4 F (about 28 C 2.2 C) and a relative humidity of 50%
10%. The
crosshead speed of the tensile tester is 2.0 inches per minute (about 5.1
cm/minute) and the gauge
length is 4.0 inches (about 10.2 cm). The TDT is the arithmetic total of MD
and CD tensile
strengths of the strips.
"Wet Burst Strength" as used herein is a measure of the ability of a fibrous
structure
and/or a paper product incorporating a fibrous structure to absorb energy,
when wet and subjected
to deformation normal to the plane of the fibrous structure and/or paper
product. Wet burst
strength may be measured using a Thwing-Albert Burst Tester Cat. No. 177
equipped with a 2000
g load cell commercially available from Thwing-Albert Instrument Company,
Philadelphia, PA.
In one embodiment, the fibrous structures of the present invention and/or
sanitary tissue products
comprising such fibrous structures may have a wet burst strength of greater
than about 10 g/cm
and/or from about 12 g/cm to about 394 g/cm and/or from about 13 g/cm to about
197 Worn
and/or from about 15 g/cm to about 197 g/cm and/or from about 15 g/cm to about
78 g/cm.
"Basis Weight" as used herein is the weight per unit area of a sample reported
in lbs/3000
ft' or g/m2. Basis weight is measured by preparing one or more samples of a
certain area (m2) and
weighing the sample(s) of a fibrous structure according to the present
invention and/or a paper
product comprising such fibrous structure on a top loading balance with a
minimum resolution of
0.01 g. The balance is protected from air drafts and other disturbances using
a draft shield.
Weights are recorded when the readings on the balance become constant. The
average weight (g)
is calculated and the average area of the samples (m2). The basis weight (g/m)
is calculated by
dividing the average weight (g) by the average area of the samples (m2). In
one embodiment, the
fibrous structures of the present invention and/or sanitary tissue products
comprising such fibrous
structures have a basis weight of from about 12 g/m2 to about 120 g/m2 and/or
from about 14 g/m2
to about 80 g/m2 and/or from about 17 g/m2 to about 70 g/m2 and/or from about
20 g/m2 to about
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WO 2004/099501 PCT/US2004/012584
60 g/m2. Typically, a single ply of the fibrous structure has a basis weight
of from about 12 g/m2
to about 50 9/1n2-
"Machine Direction" or "MD" as used herein means the direction parallel to the
flow of
the fibrous structure through the papermaking machine and/or product
manufacturing equipment.
"Cross Machine Direction" or "CD" as used herein means the direction
perpendicular to
the machine direction in the same plane of the fibrous structure and/or paper
product comprising
the fibrous structure.
"Apparent Density" or "Density" as used herein means the basis weight of a
sample
divided by the caliper with appropriate conversions incorporated therein.
Apparent density used
herein has the units g//cm3.
"Total Dry Tensile Strength" as used herein means the geometric mean of the
machine
and cross-machine breaking strengths in grams per cm of sample width.
Mathematically, this is
the square root of the product of the machine and cross-machine direction
breaking strengths in
grams per cm of sample width. In one embodiment, the fibrous structures of the
present invention
and/or sanitary tissue products comprising such fibrous structures have a
total dry tensile of
greater than about 39 g/cm and/or greater than about 59 g/cm and/or from about
63 g/cm to about
1575 g/cm and/or from about 78 g/cm to about 985 g/cm and/or from about 78
g/cm to about 394
g/cm and/or from about 98 g/cm to about 335 g/cm. Typically a single ply of
the fibrous structure
has a total dry tensile of from about 39 g/cm to about 590 g/cm.
"Flexibility" as used herein means the slope of the secant of the graph-curve
derived from
force vs. stretch % data which secant passes through the origin (0% stretch, 0
force) and through
the point on the graph-curve where the force per centimeter of width is 20
grams.
"Total Flexibility" as used herein means the geometric mean of the machine-
direction
flexibility and cross-machine-direction flexibility. Mathematically, this is
the square root of the
product of the machine-direction flexibility and cross-machine-direction
flexibility in grams per
cm.
"WABY Factor" as used herein means the ratio of Total Flexibility to Total
Tensile
Strength. The WABY Factor has been determined to be a factor which
characterizes
embodiments of the invention as being strong yet having high bulk softness.
This ratio is hereby
dubbed the WABY Factor. For instance, a sample having a Total Flexibility of
20 g/cm, and a
Total Tensile Strength of 154 g/cm has a WABY Factor of 0.13. It is desirable
that fibrous
structures and/or sanitary tissue products comprising such fibrous structures
exhibit a WABY
factor less than about 0.2 and/or from about 0.05 to about 0.15 and/or from
about 0.06 to about
0.13 and/or from about 0.06 to about 0.11.
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Briefly, tactile perceivable softness of tissue paper is inversely related to
its WABY
Factor. Also, note that the WABY Factor is dimensionless because both
Flexibility and Total
Tensile Strength as defined above are in g/cm, their ratio is dimensionless.
"B Compressibility" as used herein means the intercept of a curve generated by
plotting
weight versus thickness resulting from a compression test.
"Lint" as used herein is measured in accordance with the procedure set forth
in commonly
assigned U.S. Pat. No. 5,814,188 issued Sep. 29, 1998 to Vinson et al.
The fibrous structures and/or sanitary tissue products employing the fibrous
structures of
the present invention may be characterized as being within a multi-parametric
domain defined by
empirically determined ranges of one or more and/or two or more and/or three
or more of the
following parameters: 1) Caliper; 2) Physiological Surface Smoothness; 3) Slip
Stick Coefficient
of Friction; 4) Total Tensile Strength; 5) Flexibility; 6) Basis Weight; 7)
Wet Burst Strength; 8)
Coefficient of Friction; 9) WABY Factor and/or 10) B Compressibility.
It has surprisingly been found that fibrous structures and sanitary tissue
products
incorporating such fibrous structures that exhibit, in addition to a Slip
Stick Coefficient of
Friction less than about 0.023, a Coefficient of Friction of from about 0.65
to about 0.83 and/or
from about 0.65 to about 0.81 and/or from about 0.71 to about 0.81 and/or a B
Compressibility of
from about 15 to about 50 and/or from about 20 to about 40 exhibit enhanced
softness and/or
smoothness as compared to known fibrous structures.
As used herein, the articles "a" and "an" when used herein, for example, "an
anionic
surfactant" or "a fiber" is understood to mean one or more of the material
that is claimed or
described.
All percentages and ratios are calculated by weight unless otherwise
indicated. All
percentages and ratios are calculated based on the total composition unless
otherwise indicated.
Unless otherwise noted, all component or composition levels are in reference
to the active
level of that component or composition, and are exclusive of impurities, for
example, residual
solvents or by-products, which may be present in commercially available
sources.
Fibrous Structure
The fibrous structures and/or tissue paper of the present invention can be
made by
different methods. Nonlimiting examples of fibrous structure types and/or
tissue paper types
include conventionally pressed and/or felt-pressed tissue paper; pattern
densified tissue paper
either with a patterned forming wire and/or a patterned fabric/resin belt;
high-bulk, uncompacted
tissue paper and creped or uncreped tissue paper. The tissue paper may be of a
homogenous
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WO 2004/099501 PCT/US2004/012584
and/or single layered or multilayered construction; and tissue paper products
made therefrom may
be of a single-ply or multi-ply construction.
Further, the fibrous structures of the present invention and/or sanitary
tissue products
incorporating the same may be creped or uncreped.
Further yet, the sanitary tissue products incorporating the fibrous structures
of the present
invention may incorporate dry fibers via an air laid process and/or latex
binding agents via a wet
laid process.
Conventional converting methods may be used to convert dried rolls of fibrous
structure
according to the present invention into one-ply and/or multi-ply sanitary
tissue products.
Nonlimiting examples of such converting methods include embossing including
high pressure
embossing, dry creping, ply bonding, calendaring and/or other mechanical
treatments to the
fibrous structures.
The fibrous structure may be made with a fibrous furnish that produces a
single layer
embryonic fibrous web or a fibrous furnish that produces a multi-layer
embryonic fibrous web.
The properties described herein may be for a single ply of the fibrous
structure and/or a
single ply sanitary tissue product and/or for a multi-ply sanitary tissue
product that incorporates at
least one ply comprising the fibrous structure of the present invention.
Fiber Furnish
In one embodiment, the fibrous structure is produced from a fiber furnish. In
another
embodiment, the fibrous structure is produced from a melt blown and/or spun
bonded and/or
rotary die process. The fiber furnish of the present invention comprises one
or more fibers and
typically one or more optional ingredients.
Optional Ingredients
The fibrous structures of the present invention may comprise an optional
ingredient
selected from the group consisting of permanent wet strength resins, chemical
softeners, such as
silicones, particularly cationic silicones, and/or quaternary ammonium
compounds, temporary wet
strength resins, dry strength resins, wetting agents, lint resisting agents,
absorbency-enhancing
agents, immobilizing agents, especially in combination with emollient lotion
compositions,
antiviral agents including organic acids, antibacterial agents, polyol
polyesters, antimigration
agents, polyhydroxy plasticizers, fillers (clays), humectants and mixtures
thereof. Such optional
ingredients may be added to the fiber furnish, the embryonic fibrous web
and/or the dried fibrous
structure. Such optional ingredients may be present in the fibrous structure
at any level based on
the dry weight of the fibrous structure.
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The optional ingredients may be applied to the fiber furnish and/or the
embryonic fibrous
web and/or the dried fibrous structure and/or the sanitary tissue product of
the present invention.
Further, the optional ingredients, such as other chemical softeners, more
particularly, lotions,
especially, transferable lotions may be applied to the dried fibrous structure
and/or sanitary tissue
product after the any cationic silicone, if any, has been applied thereto.
The optional ingredients may be present in the fibrous structure and/or
sanitary tissue
product of the present invention at a level of from about 0.001% to about 50%
and/or from about
0.001% to about 30% and/or from about 0.001% to about 22% and/or from about
0.01% to about
5% and/or from about 0.03% to about 3% and/or from about 0.05 to about 2%
and/or from about
0.1 % to about 1 % by weight, on a dry fibrous structure or sanitary tissue
product basis.
Chemical Softeners
Nonlimiting examples of suitable chemical softeners include silicones,
especially cationic
silicones, more preferably cationic silicones that comprise one or more
polysiloxane units,
preferably polydimethylsiloxane units of formula -{(CH3)2SiO}c - having a
degree of
polymerization, c, of from 1 to 1000, preferably of from 20 to 500, more
preferably of from 50 to
300, most preferably from 100 to 200, and organosilicone-free units comprising
at least one
diquaternary unit. In a preferred embodiment of the present invention, the
selected cationic
silicone polymer has from 0.05 to 1.0 mole fraction, more preferably from 0.2
to 0.95 mole
fraction, most preferably 0.5 to 0.9 mole fraction of the organosilicone-free
units selected from
cationic divalent organic moieties. The cationic divalent organic moiety is
preferably selected
from N,N,N',N'- tetramethyl-1,6-hexanediammonium units.
The selected cationic silicone polymer can also contain from 0 to 0.95 mole
fraction,
preferably from 0.001 to 0.5 mole fraction, more preferably from 0.05 to 0.2
mole fraction of the
total of organosilicone-free units, polyalkyleneoxide amines of the following
formula:
[- Y - O (-CaH2aO)b - Y - ]
wherein Y is a divalent organic group comprising a secondary or tertiary
amine, preferably a Cl
to C8 alkylenamine residue; a is from 2 to 4, and b is from 0 to 100. The
polyalkyleneoxide
blocks may be made up of ethylene oxide (a = 2), propylene oxide (a = 3),
butylene oxide (a = 4)
and mixtures thereof, in a random or block fashion.
Such polyalkyleneoxide amine - containing units can be obtained by introducing
in the
silicone polymer structure, compounds such as those sold under the tradename
Jeffamine from
Huntsman Corporation. A preferred Jeffamine is Jeffamine ED-2003.
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The selected cationic silicone polymer can also contain from 0, preferably
from 0.001 to
0.2 mole fraction, of the total of organosilicone-free units, of -NR3+ wherein
R is alkyl,
hydroxyalkyl or phenyl. These units can be thought of as end-caps.
Moreover the selected cationic silicone polymer generally contains anions,
selected from
inorganic and organic anions, more preferably selected from saturated and
unsaturated C1-C20
carboxylates and mixtures thereof, to balance the charge of the quaternary
moieties, thus the
cationic silicone polymer also comprises such anions in a quaternary charge-
balancing proportion.
Conceptually, the selected cationic silicone polymers herein can helpfully be
thought of
as non-crosslinked or "linear" block copolymers including non-fabric-
substantive but surface
energy modifying "loops" made up of the polysiloxane units, and fabric-
substantive "hooks". One
preferred class of the selected cationic polymers (illustrated by Structure 1
hereinafter) can be
thought of as comprising a single loop and two hooks; another, very highly
preferred, comprises
two or more, preferably three or more "loops" and two or more, preferably
three or more "hooks"
(illustrated by Structures 2a and 2b hereinafter), and yet another
(illustrated by Structure 3
hereinafter) comprises two "loops" pendant from a single "hook".
Of particular interest in the present selection of cationic silicone polymers
is that the
"hooks" contain no silicone and that each "hook" comprises at least two
quaternary nitrogen
atoms.
Also of interest in the present selection of preferred cationic silicone
polymers is that the
quaternary nitrogen is preferentially located in the "backbone" of the
"linear" polymer, in
contradistinction from alternate and less preferred structures in which the
quaternary nitrogen is
incorporated into a moiety or moieties which form a "pendant" or "dangling"
structure off the
"backbone".
The structures are completed by terminal moieties which can be noncharged or
charged.
Moreover a certain proportion of nonquaternary silicone-free moieties can be
present, for example
the moiety [- Y - 0 (-CaH2aO)b - Y - ] as described hereinabove.
Of course the conceptual model presented is not intended to be limiting of
other moieties,
for example connector moieties, which can be present in the selected cationic
silicone polymers
provided that they do not substantially disrupt the intended function as
tissue benefit agents.
In more detail, the cationic silicone polymers herein have one or more
polysiloxane units
and one or more quaternary nitrogen moieties, including polymers wherein the
cationic silicone
polymer has the formula:
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WO 2004/099501 PCT/US2004/012584
Rl Rl Ri n
2aO 'X-Z nA
Z-X- f OCaH2a R2 Si0 Si0 Si -R22tCH
R1 R3 d Rl
c
STRUCTURE I
wherein:
- R' is independently selected from the group consisting of: CI-22 alkyl,
C2_22 alkenyl,
C6.22 alkylaryl, aryl, cycloalkyl, and mixtures thereof;
- R2 is independently selected from the group consisting of. divalent organic
moieties that may
contain one or more oxygen atoms (such moieties preferably consist essentially
of C and H or of
C, H and 0);
- X is independently selected from the group consisting of ring-opened
epoxides;
-R 3 is independently selected from polyether groups having the formula:
-M'(CaH2aO)b-M2
wherein M' is a divalent hydrocarbon residue; M2 is independently selected
from the group
consisting of H, C1_22 alkyl, C2.22 alkenyl, C6.22 alkylaryl, aryl,
cycloalkyl, C1.22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy alkyl, and mixtures thereof;
- Z is independently selected from the group consisting of monovalent organic
moieties
comprising at least one quaternized nitrogen atom;
- a is from 2 to 4; b is from 0 to 100; c is from 1 to 1000, preferably
greater than 20, more
preferably greater than 50, preferably less than 500, more preferably less
than 300, most
preferably from 100 to 200;
- d is from 0 to 100; n is the number of positive charges associated with the
cationic silicone
polymer, which is greater than or equal to 2; and A is a monovalent anion.
In a preferred embodiment of the Structure 1 cationic silicone polymers, Z is
independently selected from the group consisting of
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R12 R12 0
13 1 15 I I 12
(i)-N-R (ii) - fCH2)R-C-R
R14 R14
R12
17 /-~ p I I
(in) __N R16 N~R (iv) -N N-CH2-C-O-R12
R14 R Ia Rl
(v) monovalent aromatic or aliphatic heterocyclic group, substituted or
unsubstituted,
containing at least one quaternized nitrogen atom;
wherein:
- R12, R13, R14 are the same or different, and are selected from the group
consisting of. C1_22 alkyl,
C2_22 alkenyl, C6_22 alkylaryl, aryl, cycloalkyl, C1.22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy
alkyl, and mixtures thereof;
- Ri5 is -0- or NR19;
- R16 is a divalent hydrocarbon residue;
- R'7, R'$, R'9 are the same or different, and are selected from the group
consisting of: H, CI-22
alkyl, C2.22 alkenyl, C6_22 alkylaryl, aryl, cycloalkyl, CI-22 hydroxyalkyl,
polyalkyleneoxide,
(poly)alkoxy alkyl, and mixtures thereof; and e is from 1 to 6.
In a highly preferred embodiment, the cationic silicone polymers herein have
one or more
polysiloxane units and one or more quaternary nitrogen moieties, including
polymers wherein the
cationic silicone polymer has the formula: (Structure 2a)
STRUCTURE 2a: Cationic silicone polymer composed of alternating units of-
(i) a polysiloxane of the following formula
R R R
X-- -OCaH2~- 2 Si0 SO Si-R C.H2a0
R1 R3 R1
and
(ii) a divalent organic moiety comprising at least two quaternized nitrogen
atoms.
Note that Structure 2a comprises the alternating combination of both the
polysiloxane of
the depicted formula and the divalent organic moiety, and that the divalent
organic moiety is
organosilicone-free corresponding to a preferred "hook" in the above
description.
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WO 2004/099501 PCT/US2004/012584
In this preferred cationic silicone polymer, Rl is independently selected from
the group
consisting of. CI-22 alkyl, C2_22 alkenyl, C6.22 alkylaryl, aryl, cycloalkyl,
and mixtures thereof;
- R2 is independently selected from the group consisting of. divalent organic
moieties that may
contain one or more oxygen atoms; X is independently selected from the group
consisting of ring-
opened epoxides; R3 is independently selected from polyether groups having the
formula:
-M1(CaH2aO)b-M2
wherein Ml is a divalent hydrocarbon residue; M2 is independently selected
from the group
consisting of H, C1_22 alkyl, C2_22 alkenyl, C6_22 alkylaryl, aryl,
cycloalkyl, CI-22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy alkyl, and mixtures thereof; a is from 2 to 4;
b is from 0 to 100; c
is from 1 to 1000, preferably greater than 20, more preferably greater than
50, preferably less than
500, more preferably less than 300, most preferably from 100 to 200; and d is
from 0 to 100.
In an even more highly preferred embodiment of the Structure 2a cationic
silicone
polymer, the cationic silicone polymer has the formula Structure 2b wherein
the polysiloxane (i)
of the formula described above in Structure 2a is present with (ii) a cationic
divalent organic
moiety is selected from the group consisting of:
R4 R6 m
(a) N+ Z1 IV- 2mA
RS R7
/--\ t m 2mA
(b) ~; \R Z Rl ~~
R4 R6 R$ Rl m
I (D I (D I@ , 10 4mA
(c) N-Z-N-Z-N-Z-N
RS R R RI i
(d) a divalent aromatic or aliphatic heterocyclic group, substituted or
unsubstituted, containing at least
one quaternized nitrogent atom; and
(iii) optionally, a polyalkyleneoxide amine of formula:
[- Y - O (-CaH2aO)b - Y - ]
- Y is a divalent organic group comprising a secondary or tertiary amine,
preferably a
Cl to C8 alkylenamine residue; a is from 2 to 4; b is from 0 to 100; the
polyalkyleneoxide blocks may be made up of ethylene oxide (a = 2), propylene
oxide
13
CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
,(a = 3), butylene oxide (a = 4) and mixtures thereof, in a random or block
fashion;
and
(iv) optionally, a cationic monovalent organic moiety, to be used as an end-
group,
selected from the group consisting of:
R12 R12 0
13 _ T 15 I I
12
(1-N-R (ii) -N-ECH2 e R C-R
R14 R14
R12 0
I(D 16 iR 17 11 R12
(iv) -N NCH2-C-O- (in) -N-R-N-,is
114 R \\---j Rl
(v) monovalent aromatic or aliphatic heterocyclic group, substituted or
unsubstituted,
containing at least one quatemized nitrogen atom;
wherein:
- R4, R5, R6, R7, R8, R9, R10, R" are the same or different, and are selected
from the group
consisting of: CI-22 alkyl, C2_22 alkenyl, C6_22 alkylaryl, aryl, cycloalkyl,
C1_22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy alkyl, and mixtures thereof; or in which R4
and R6, or R5 and R7,
or R8 and R10, or R9 and RI1 may be components of a bridging alkylene group;
- R12, R13, R14 are the same or different, and are selected from the group
consisting of: C1_22 alkyl,
C2.22 alkenyl, C6_22 alkylaryl, C1_22 hydroxyalkyl, polyalkyleneoxide,
(poly)alkoxy alkyl groups,
and mixtures thereof; and
- R15 is -0- or NR19;
- R16 and M1 are the same or different divalent hydrocarbon residues;
- R17, R18, R19 are the same or different, and are selected from the group
consisting of. H, CI-22
alkyl, C2_22 alkenyl, C6_22 alkylaryl, aryl, cycloalkyl, CI-22 hydroxyalkyl,
polyalkyleneoxide,
(poly)alkoxy alkyl, and mixtures thereof; and
- Z' and Z2 are the same or different divalent hydrocarbon groups with at
least 2 carbon atoms,
optionally containing a hydroxy group, and which may be interrupted by one or
several ether,
ester or amide groups;
wherein, expressed as fractions on the total moles of the organosilicone -
free moieties, the
cationic divalent organic moiety (ii) is preferably present at of from 0.05 to
1.0 mole fraction,
more preferably of from 0.2 to 0.95 mole fraction, and most preferably of from
0.5 to 0.9 mole
fraction; the polyalkyleneoxide amine (iii) can be present of from 0.0 to 0.95
mole fraction,
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CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
preferably of from 0.001 to 0.5, and more preferably of from 0.01 to 0.2 mole
fraction; if present,
the cationic monovalent organic moiety (iv) is present of from 0 to 0.2 mole
fraction, preferably
of from 0.001 to 0.2 mole fraction;
- e is from 1 to 6; m is the number of positive charges associated with the
cationic divalent
organic moiety, which is greater than or equal to 2; and A is an anion.
Note that Structure 2b comprises the alternating combination of both the
polysiloxane of
the depicted formula and the divalent organic moiety, and that the divalent
organic moiety is
organosilicone-free corresponding to a preferred "hook" in the above general
description.
Structure 2b moreover includes embodiments in which the optional
polyalkyleneoxy and/or end
group moieties are either present or absent.
In yet another embodiment, the cationic silicone polymers -herein have one or
more
polysiloxane units and one or more quaternary nitrogen moieties, and including
polymers wherein
the cationic silicone polymer has the formula: (Structure 3)
RI R1 R1 R1 R1 IIRi
R1 IiO IiO I i-R2-( CaHzaO X- W- X-{ OCaHza Rz - I i OSIi OSi Rh nA
I I I I I I
R' c R3 d R1 R1 R3 d RI c
n
STRUCTURE 3
wherein:
- R1 is independently selected from the group consisting of. C1.22 alkyl,
C2_22 alkenyl,
C6.22 alkylaryl, aryl, cycloalkyl, and mixtures thereof;
- R2 is independently selected from the group consisting of. divalent organic
moieties that may
contain one or more oxygen atoms;
- X is independently selected from the group consisting of ring-opened
epoxides;
- R3 is independently selected from polyether groups having the formula:
-M' (CaH2aO)b-M2
wherein M1 is a divalent hydrocarbon residue; M2 is independently selected
from the group
consisting of H, C1_22 alkyl, C2_22 alkenyl, C6.22 alkylaryl, aryl,
cycloalkyl, C1_22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy alkyl, and mixtures thereof;
- X is independently selected from the group consisting of ring-opened
epoxides;
- W is independently selected from the group consisting of divalent organic
moieties comprising
at least one quaternized nitrogen atom;
CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
- a is from 2 to 4; b is from 0 to 100; c is from 1 to 1000, preferably
greater than 20, more
preferably greater than 50, preferably less than 500, more preferably less
than 300, most
preferably from 100 to 200; d is from 0 to 100; n is the number of positive
charges associated
with the cationic silicone polymer, which is greater than or equal to 1; and A
is a monovalent
anion, in other words, a suitable counterion.
In preferred cationic silicone polymers of Structure 3, W is selected from the
group
consisting of.
R4 R6 in
(a) N+ 1 TV- 2mA
RS R7
/--\0+ E in
2mA
(b) N N-Z -N N--
\--/ Rl R1/
R4 R6 R$ R1 in
I Q+ I I Q 2 10 1 I 4mA
(c) N-Z-N-Z-N-Z-
R R 7 R 9 R' 1
(d) a divalent aromatic or aliphatic heterocyclic group, substituted or
unsubstituted, containing at least
one quaternized nitrogent atom; and
wherein
- R4, R5, R6, R', R8, R9, R10, R' 1 are the same or different, and are
selected from the group
consisting of: C1_22 alkyl, C2_22 alkenyl, C6_22 alkylaryl, aryl, cycloalkyl,
C1_22 hydroxyalkyl,
polyalkyleneoxide, (poly)alkoxy alkyl, and mixtures thereof; or in which R4
and R6, or R5 and R7,
or R8 and R10, or R9 and R' 1 may be components of a bridging alkylene group;
and
- Z' and Z2 are the same or different divalent hydrocarbon groups with at
least 2 carbon atoms,
optionally containing a hydroxy group, and which may be interrupted by one or
several ether,
ester or amide groups.
The cationic silicone polymer may be applied to the embryonic fibrous web
and/or
applied to a dried fibrous structure and/or before and/or concurrently and/or
after converting one
or more dried fibrous structures into a sanitary tissue product. Nonlimiting
examples of suitable
processes for applying the cationic silicone polymer to the fibrous structure
include spraying,
including but not limited to using a spraying disk, onto the embryonic fibrous
web and/or dried
fibrous structure before it is wound into a roll of paper, extruding,
especially via slot extrusion,
onto the embryonic web and/or dried fibrous structure, and/or by printing,
especially gravure
16
CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
printing, onto the embryonic fibrous web and/or dried fibrous structure and/or
sanitary tissue
product.
The cationic silicone polymer may be applied to the embryonic fibrous web
and/or dried
fibrous structure and/or sanitary tissue product in a homogeneous and/or
patterned and/or
inhomogeneous fashion.
The cationic silicone polymer can be applied to the embryonic fibrous web
and/or fibrous
structure and/or sanitary tissue product of the present invention as it is
being made on a
papermaking machine or thereafter: either while it is wet (i.e., prior to
final drying) or dry (i.e.,
after final drying).
In one embodiment, an aqueous mixture containing the cationic silicone polymer
is
sprayed onto the embryonic fibrous web and/or fibrous structure and/or
sanitary tissue product as
it courses through the papermaking machine: for example, and not by way of
limitation, referring
to a papermaking machine of the general configuration disclosed in U.S. Patent
No. 3,301,746,
either before the predryer, or after the predryer, or even after the Yankee
dryer/creping station
although the fibrous structure is preferably creped after the cationic
silicone polymer is applied.
The cationic silicone polymer can be applied to the embryonic fibrous web in
an aqueous
solution, emulsion, or suspension. The cationic silicone polymer can also be
applied in a solution
containing a suitable, nonaqueous solvent, in which the cationic silicone
polymer dissolves or
with which the cationic silicone polymer is miscible: for example, hexane. The
cationic silicone
polymer may be supplied in neat form or, preferably, emulsified with a
suitable surfactant
emulsifier. The cationic silicone polymer can be applied after embryonic
fibrous web formation
has been effected. In a typical process, the embryonic fibrous web is formed
and then dewatered
prior to cationic silicone polymer application in order to reduce the loss of
cationic silicone
polymer due to drainage of free water. The cationic silicone polymer can be
applied to the wet
embryonic fibrous web at a fiber consistency of greater than about 15% in the
manufacture of
conventionally pressed tissue paper; and to a wet embryonic fibrous web having
a fiber
consistency of between about 20% and about 35% in the manufacture of tissue
paper in
papermaking machines wherein the newly formed embryonic fibrous web is
transferred from a
fine mesh Fourdrinier to a relatively coarse imprinting/carrier fabric and/or
belt.
Methods of applying the cationic silicone polymer to the embryonic fibrous web
and/or
dried fibrous structure and/or sanitary tissue product include spraying, slot
extrusion and gravure
printing. Other methods include deposition of the cationic silicone polymer
onto a forming wire
or fabric or belt which is then contacted by the embryonic fibrous web and/or
dried fibrous
structure and/or sanitary tissue product. Equipment suitable for spraying
cationic silicone
17
CA 02523571 2007-08-15
polymer-containing liquids onto embryonic fibrous webs and/or dried fibrous
structures and/or
sanitary tissue products include external mix, air atomizing nozzles such as
the 2 mm nozzle
available from V.I.B. Systems, Inc., Tucker, Ga. Equipment suitable for
printing cationic silicone
polymer-containing liquids onto embryonic fibrous webs and/or dried fibrous
structures and/or
sanitary tissue products includes rotogravure printers.
The cationic silicone polymer can be applied uniformly to the embryonic
fibrous web
and/or dried fibrous structure and/or sanitary tissue product. A uniform
distribution is desirable
so that substantially the entire sheet benefits from the tactile effect of the
cationic silicone
polymer. Continuous and patterned distributions are both within the scope of
the invention and
meet the above criteria.
Application methods described herein for the cationic silicone polymer can be
used with
dry or wet embryonic fibrous webs and/or fibrous structures and/or sanitary
tissue products.
Exemplary art related to the addition of silicone materials to the fibrous
structure during
its formation includes U.S. Pat. No. 5,059,282 issued to Ampulski, et. al. on
Oct. 22, 1991
The Ampulsld patent discloses a process for adding a
polysiloxane compound to a wet tissue web ("fibrous structure") (preferably at
a fiber consistency
between about 20% and about 35%). Such a method represents an advance in some
respects over
the addition of chemicals into the slurry vats supplying the papermaking
machine. For example,
such means target the application to one of the web surfaces as opposed to
distributing the
additive onto all of the fibers of the furnish.
t Considerable art has been devised to apply silicones and/or other chemical
softeners to
already-dried paper webs ("fibrous structures") either at the so-called dry
end of the papermaking
machine or in a separate converting operation subsequent to the papermakking
step. Exemplary art
from this field includes U.S. Pat. No. 5,215,626 issued to Ampulski, et. al,
on Jun. 1, 1993; U.S.
Pat. No. 5,246,545 issued to Ampulski, et. al. on Sep. 21, 1993; and U.S. Pat.
No. 5,525,345
issued to Warner, et. al. on Jun. It, 1996 The U.S. Pat. No.
5,215,626 discloses a method for preparing soft tissue paper by applying a
polysiloxane to a dry
web ("fibrous structure"). The U.S. Pat. No.5,246,545 Patent discloses a
similar method utilizing
a heated transfer surface. Finally, the Warner Patent discloses methods of
application including
roll coating and extrusion for applying particular compositions to the surface
of a dry tissue web
("fibrous structure").
The cationic silicone may be applied to one or both surfaces of an embryonic
web and/or
dried fibrous structure and/or sanitary tissue product such that one or both
external surfaces of a
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CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
resulting sanitary tissue product incorporating the fibrous structure has the
cationic silicone
polymer present thereon.
In one embodiment, the cationic silicone may be applied to one surface of an
embryonic
web and/or dried fibrous structure and/or sanitary tissue product such that
the cationic silicone
passes through the embryonic web and/or dried fibrous structure and/or
sanitary tissue product
such that both surfaces of an embryonic web and/or fibrous structure and/or
sanitary tissue
product have cationic silicone present thereon.
The fibrous structure of the present invention and/or sanitary tissue product
incorporating
such fibrous structure may comprise from about 0.0001% to about 10% and/or
from about
0.001% to about 5% and/or from about 0.005% to about 3% and/or from about
0.005% to about
2% and/or from about 0.005% to about 1.5% by dry weight of the fibrous
structure or sanitary
tissue product of the cationic silicone polymer.
Reference is made to the following patents and patent applications which do
also disclose
cationic silicone polymers suitable for use in the present invention: WO 02/06
403;
WO 02/18528, EP 1 199 350; DE OS 100 36 533; WO 00/24853; WO 02/10259; WO
02/10257
and WO 02/10256.
Synthesis Example - When not otherwise known or available in commerce, the
cationic
silicone polymers herein can be prepared by conventional techniques as
disclosed in
WO 02/18528.
Other silicone compounds besides the cationic silicones discussed above can be
used as
chemical softeners. Nonlimiting examples of such other silicone compounds that
are suitable for
the present invention include silicone emulsions, particularly aminosilicones.
Suitable
aminosilicones are available under the tradename AF2130, which is commercially
available from
Wacker Silicones.
Processes of the Present Invention:
The fibrous structure of the present invention may be made by any suitable
papermaking
process.
A nonlimiting example of a suitable papermaking process for making the fibrous
structure
of the present invention is described as follows.
In one embodiment, a fiber furnish is prepared by mixing one or more fibers
with water.
One or more additional optional ingredients may be added to the fiber furnish.
The fiber furnish
may then be put into a headbox, which may be a layered headbox, of a
papermaking machine.
The fiber furnish may then be deposited on a foraminous surface to form a
single layer or a multi-
layer embryonic fibrous web. The cationic silicone polymer and/or optional
ingredients may be
19
CA 02523571 2007-08-15
added to the embryonic fibrous web by spraying and/or extruding and/or
printing and/or by any
other suitable process known to those of ordinary skill in the art. The
embryonic web may then
be transferred to a through air drying belt and/or a Yankee dryer such that
the embryonic fibrous
web is dried via through-air drying and/or via the Yankee dryer. From the
through-air drying belt,
if there is one present, the fibrous structure may be transferred to a Yankee
dryer. From the
Yankee dryer, the fibrous structure may be transferred to a rewinder to form a
roll of dried fibrous
structure. During this transfer step, the cationic silicone polymer and/or
optional ingredients may
be applied to the dried fibrous structure. The fibrous structure may be
converted into various
paper products, particularly sanitary tissue products, both in single-ply
forms and/or in multi-ply
forms. During the converting step, the cationic silicone polymer may be
applied to the fibrous
structure. Accordingly, the cationic silicone polymer may be applied before
and/or concurrently
with and/or after the converting step.
Test Methods
A. Coefficient of Friction
The coefficient of friction is obtained using a KES-4BF surface analyzer with
a modified
friction probe as described in "Methods for the Measurement of the Mechanical
Properties of
Tissue Paper", Ampulski, et. at., 1991 International Paper Physics Conference,
published by
TAPPI press,.
The substrate used for the friction evaluation, as disclosed herein, is a
laboratory prepared
handsheet, prepared according to TAPPI standard T-205 incorporated herein by
reference. The
friction is measured on the smooth side of the handsheet (the side which is
dried against a metal
plate according to the method).
The substrate is advanced at I mm/sec constant rate for the measurement and
the friction
probe is modified from the standard instrument probe to a two centimeter
diameter 40-60 micron
glass flit.
When using a 19.6 g normal force on the probe and the heretofore specified
translation
rate for the substrate, the coefficient of friction can be calculated by
dividing the frictional force
by the normal force. The frictional force is the lateral force on the probe
during the scanning, an
output of the instrument.
The average of coefficient of friction obtained by a single scan in the
forward direction
and a single scan in the reverse direction is reported as the coefficient of
friction for the specimen.
B. Physiological Surface Smoothness
Physiological surface smoothness as used herein is a factor (hereinafter the
PSS Factor)
derived from scanning machine-direction tissue paper samples with a
profilometer (described
CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
below) having a diamond stylus, the profilometer being installed in a surface
test apparatus such
as, for example, Surface Tester KES-FB-4 which is available from KATO TECH
CO., LTD.,
Karato-Cho, Nishikiyo, Minami-Ku, Koyota, Japan. In this tester, a sample of
tissue is mounted
on a motorized drum, and a stylus is gravitationally biased towards the drum
at the 12 o'clock
position. The drum is rotated to provide a sample velocity of one (1)
millimeter per second, and
moves the sample 2 cm. with respect to the probe. Thus, the probe scans a 2 cm
length of the
sample. The profilometer comprises means for counterbalancing the stylus to
provide a normal
force of 270 mg. Basically, the instrument senses the up and down
displacements (in mm) of the
stylus as a 2 cm length of sample is scanned under the profilometer probe. The
resulting stylus-
amplitude vs. stylus-distance-scanned data are digitized, and then converted
to a stylus-amplitude
vs. frequency spectrum by performing a Fourier Transform using the Proc
Spectra standard
program available from SAS Institute Inc., Post Office Box 10066, Raleigh,
N.C. 27605. This
identifies spectral components in the sample's topography; and the frequency
spectral data are
then adjusted for human tactile responsiveness as quantified and reported by
Verrillo (Ronald T.
Verrillo, "Effect of Contractor Area on the Vibrotactile Threshold", The
Journal of the
Accoustical Society of America, 35, 1962 (1963)). However, whereas Verrillo's
data are in the
time domain (i.e., cycles per second), and physiological surface smoothness is
related to finger-to-
sample velocity, Verrillo-type data are converted to a spatial domain (i.e.,
cycles per millimeter)
using 65 mm/sec as a standard finger-to-sample velocity factor. Finally, the
data are integrated
from zero (0) to ten (10) cycles per millimeter. The result is the PSS Factor.
Graphically, the PSS
Factor is the area under the Verrillo-adjusted frequency (cycles/mm) vs.
stylus amplitude curve
between zero (0) and ten (10) cycles per millimeter. Preferably, PSS Factors
are average values
derived from scanning multiple samples (e.g., ten samples), both forward and
backward.
The profilometer described above comprises, more specifically, a Gould
Surfanalyzer
Equipment Controller #21-1330-20428, Probe #21-3100-465, Diamond stylus tip
(0.0127 mm
radius) #21-0120-00 and stylus tip extender #22-0129-00 all available from
Federal Products,
Providence, R.I. The profilometer probe assembly is fitted with a
counterbalance, and set up as
depicted in FIG. 22 of U.S. Pat. No. 4,300,981 (referenced hereinbefore).
C. Slip Stick Coefficient of Friction
Slip Stick Coefficient of Friction (hereinafter S&S COF) is defined as the
mean deviation
of the coefficient of friction. It is dimensionless. It may be determined
using commercially
available test apparatus such as, for example, the Kato Surface Tester
identified above which has
been fitted with a stylus which is configured and disposed to slide on the
surface of the sample
being scanned: for example, a fritted glass disk. When a sample is scanned as
described above, the
21
CA 02523571 2007-08-15
instrument senses the lateral force on the stylus as the sample is moved
thereunder: i.e., scanned.
The lateral force is called the frictional force; and the ratio of frictional
force to stylus weight is
the coefficient of friction, COF. The instrument then calculates and reports
the S&S COF for each
scan of each sample.
D. B Compressibility Test
A circular sample (single ply or multi-ply) of a fibrous structure and/or a
sanitary tissue
product to be tested having a 2.5 inch diameter is placed on a Thwing-Albert
Compressibility
Tester, commercially available from Thwing-Albert. A weight of up to 1500 g is
placed on the
sample at a test speed according to the Tester.
The thickness of the sample is measured/recorded at every 1 g of weight. The
paired data
(weight (X) vs. thickness (Y)) is then placed in an X-Y graph using Microsoft
Excel Program.
After the X -Y graph is created, a trendline that is logarithmic which has an
equation:
Y=Mln(X)+B
wherein M is the slope of the curve and B is the intercept. B is the B
Compressibility value of the
fibrous structures and/or sanitary tissue products incorporating such fibrous
structures of the
present invention.
Nonlimiting Examples
The following nonlimiting examples employ a cationic silicone polymer in
accordance
with the present invention. The cationic silicone polymer is used typically in
the form of an
emulsion containing an amine oxide, a nonionic surfactant, ethanol and water.
In one
embodiment, the emulsion is formed as follows: 24.39 g of cationic silicone
solution (80%
cationic silicone polymer/20% ethanol) is mixed with 6.05 g C12-15 E03 (4)
with a normal
laboratory blade mixer. After 10 minutes, 6.7g of ethanol is added. After
another 10 minutes,
8.71 g of C12-14 alkyl dimethyl amineoxide 31% active solution in water (2) is
added. After
another 10 minutes, ,54.2 g of demineralized water are quickly added to the
mixture, under
continuous stirring. The pH of the emulsion is brought to pH 7.5 with 0.8 g
O.1M HCI. The
emulsion can be diluted to about 10-20% cationic silicone polymer
concentration.
Example I- A nonlimiting embodiment of a fibrous structure, such as a facial
tissue, in
accordance with the present invention is prepared as follows.
An aqueous slurry of Northern Softwood Kraft (NSK) of about 3% consistency is
made
up using a conventional pulper and is passed through a stock pipe toward the
headbox of the
TM
Fourdrinier. A 1% dispersion of Hercules' Kymene 557 LX is prepared and is
added to the NSK
stock pipe at a rate sufficient to deliver about 0.8% Kymene 557 LX based on
the dry weight of
the ultimate sanitary tissue paper. The absorption of the permanent wet
strength resin is enhanced
22
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WO 2004/099501 PCT/US2004/012584
by passing the treated slurry through an in-line mixer. An aqueous solution of
Carboxymethyl
cellulose (CMC) dissolved in water and diluted to a solution strength of 1% is
added next to the
NSK stock pipe after the in-line mixer at a rate of about 0.1% CMC by weight
based on the dry
weight of the ultimate sanitary tissue paper. The aqueous slurry of NSK fibers
passes through a
centrifugal stock pump to aid in distributing the CMC. An aqueous dispersion
of DiTallow
DiMethyl Ammonium Methyl Sulfate (DTDMAMS) (170 F/76.6 C) at a concentration
of 1%
by weight is added to the NSK stock pipe at a rate of about 0.1% by weight
DTDMAMS based on
the dry weight of the ultimate sanitary tissue paper.
An aqueous slurry of acacia pulp fibers (from PT Tel - Indonesia) of about
1.5% by
weight is made up using a conventional repulper and is passed through a stock
pipe toward the
headbox of the Fourdrinier. This Acacia furnish joins the NSK slurry at the
fan pump where both
are diluted with white water to about 0.2% consistency.
An aqueous slurry of Acacia pulp fibers (from PT Tel - Indonesia) of about 3%
by
weight is made up using a conventional repulper. The Acacia slurry passes to
the second fan
pump where it is diluted with white water to a consistency of about 0.2%.
The slurries of NSK/acacia and acacia are directed into a multi-channeled
headbox
suitably equipped with layering leaves to maintain the streams as separate
layers until discharged
onto a traveling Fourdrinier wire. A three-chambered headbox is used. The
acacia slurry
containing 48% of the dry weight of the ultimate sanitary tissue paper is
directed to the chamber
leading to the layer in contact with the wire, while the NSK/acacia slurry
comprising 52% (27-
35% NSK and 17-25% acacia) of the dry weight of the ultimate paper is directed
to the chamber
leading to the center and inside layer. The NSK/acacia and acacia slurries are
combined at the
discharge of the headbox into a composite slurry.
The composite slurry is discharged onto the traveling Fourdrinier wire and is
dewatered
assisted by a deflector and vacuum boxes.
The embryonic wet web is transferred from the Fourdrinier wire, at a fiber
consistency of
about 17% by weight at the point of transfer, to a patterned drying fabric.
The drying fabric is
designed to yield a pattern-densified tissue with discontinuous low-density
deflected areas
arranged within a continuous network of high density (knuckle) areas. This
drying fabric is
formed by casting an impervious resin surface onto a fiber mesh supporting
fabric. The
supporting fabric is a 48 x 52 filament, dual layer mesh. The thickness of the
resin cast is about 9
mil above the supporting fabric. The knuckle area is about 35-50% and the open
cells remain at a
frequency of about 10-87 per cm2.
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CA 02523571 2005-10-25
WO 2004/099501 PCT/US2004/012584
Further de-watering is accomplished by vacuum assisted drainage until the web
has a
fiber consistency of about 23-27%.
While remaining in contact with the patterned forming fabric, the patterned
web is pre-
dried by air blown through to a fiber consistency of about 60% by weight.
The semi-dry web is then adhered to the surface of a Yankee dryer with a
sprayed creping
adhesive comprising a 0.250% aqueous solution of polyvinyl alcohol. The
creping adhesive is
delivered to the Yankee surface at a rate of 0.1 % adhesive solids based on
the dry weight of the
web. The fiber consistency is increased to about 98% before the web is dry
creped from the
Yankee with a doctor blade. After the doctor blade, the web is calendared
across all its width
with a steel to rubber calendar roll operating at a loading of 2-3.5 MPa.
The resulting tissue has a basis weight of about 20-25 g/m2; a 1-ply total dry
tensile
between 225 and 300 g/cm, a 1-ply wet burst between 30 and 65 gr/cm and a 2-
ply caliper of
about 0.035-0.05 cm. The resulting tissue is then combined with a like sheet
to form a two-ply,
creped, pattern-densified tissue so that the acacia fibers face the outside
and it is subjected to
calendaring between two smooth steel calendar rolls. The cationic silicone
polymer emulsion is
then slot extruded onto both sides in contact with a human's skin, at an add-
on amount of
approximately 0.8-1.0 g/m2 of emulsion per side, equivalent to a total add-on
level of 0.7-1.0% by
weight of silicone per ply, based on the total weight of fibers. Product is
then ply-bonded using a
mechanical plybond wheel to ensure that both plies stay together. The
resulting two-ply tissue
has a) a total basis weight of about 39-50 g/m2; b) a 2-ply total dry tensile
between 450 and 550
gr/cm; c) a 2-ply wet burst between 55 and 120 gr/cm; d) a 4-ply caliper of
about 0.05 and 0.09
cm; e) a slip-stick coefficient of friction (MMD) of about 0.0146-0.0172; f) a
Coefficient of
Friction (MIU) of about 0.734 - 0.742; g) a B Compressibility of 29-31; h) a
calculated WABY
factor of about 0.0786-0.0836; i) a PAA of about 720-770; and j) a lint of
about 9 - 12 lint units.
The resultant tissue paper is judged significantly softer than an untreated
tissue sample by
a panel of expert judges.
All documents cited in the Detailed Description of the Invention are, in
relevant part,
incorporated herein by reference; the citation of any document is not to be
considered as an
admission that it is prior art with respect to the present invention.
While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention. It is
therefore intended to cover in the appended claims all such changes and
modifications that are
within the scope of this invention.
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