Note: Descriptions are shown in the official language in which they were submitted.
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
TITLE
Elongated Pile Sub-Assembly, Guide Apparatus and
Pile Sub-Assembly Articles of Manufacture
This application claims the benefit of U.S. Provisional
Application No. 60/336,226, filed October 29, 2001.
FIELD OF THE INVENTION
so The present invention relates to an elongated pile sub-
assembly, pile sub-assembly articles and a guide apparatus that is useful
for the purpose of making a brush, or making a pile or bristle surface
structure such as a floor covering, a wall covering or an automotive
component. More particularly, the present invention concerns an
s5 elongated pile sub-assembly have a "root" end for secure anchoring of the
elongated pile sub-assembly on or through a substrate.
BACKGROUND OF THE INVENTION
The following disclosures may be relevant to various aspects of
2 o the present invention and may be briefly summarized as follows:
Conventional tuftstrings made from yarn are normally in a "U"
shape when attached or tufted into a backing substrate. The "U" shape is
formed when a yarn segment is attached to an elongated strand near the
medial point of the yarn segment. This "U" shape is similar to that of a
25 needle tufted yarn which also forms two distinct and identifiable tufts
from
one yarn segment. This "U" shaped tuftstring is disclosed in prior art
such as WO 99/29949 to Veenema et al., and US patents) 5,472,762 to
Edwards et al.
A "U" shaped tuftstring for wall or floor coverings is normally
3 o attached to a backing structure first, to form a pile fabric or carpet.
The
point of attachment for the "U" shaped tuftstring is at the bottom of the "U"
shape, which is also where the yarn and the support beam bond to one
another. This bond area is generally a solid mass of fibers fused together
providing only a small surface area to contact with and bond to a support
35 substrate. The bond between the "U" shaped tuftstring can be formed
-1-
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
using a thermal or solvent fusing process, adhesives, or mechanical
interlocking means. This small contact area generally produces low "tuft-
lock" values (e.g. the force at which the bond fails). Additionally, the
rounded bottom of the "U" is susceptible to rotation (see Figs. 1 B and 1 C)
which can cause undesirable visible defects. Figure 1 C shows one
example of the effect of such rotation on a "U" shaped tuftstring. The
bottom of the "U" tips or tilts to one side when aligned with a ridgeline
105a on the surface of a substrate 105 having an embedded
reinforcement fiber. This form of rotation causes density variations in the
so finished product. Another example of "U" shaped tuftstring rotation is the
undesirable visible defect that occurs when the tufts on one side of the "U"
have a higher frictional drag than the opposite side tuft during the
insertion/bonding process causing the tuftstring to pivot laterally (see Fig
1 B). When this occurs, one row of tufts effectively becomes longer while
the other row is effectively shortened by the same incremental length.
These linear variations or visible defects are referred to as "rowiness".
Additionally, when an adhesive is used for attaching the "U"
shape to a substrate, the top surface of the adhesive is generally above
the reference plane 300 of Fig 5B and thus, an unwanted, performance
2 o altering (e.g. reduction in the softness of the pile) wicking of the
adhesive
into the tuft may occur.
Another disadvantage of the "U" shaped tuftstring, is that the
two yarn ends of the "U" shaped tuftstring have a sizable gap between
them when manufactured. This gap is reduced when the tuftstring is
positioned in close proximity to other tuftstrings due to compression or
interference with other tufts from adjacent tuftstrings. However, this
compression or interference may be another source of density variations
as some of the pile filaments may be separated such that they are all not
in vertical alignment. Some filaments are directed toward the substrate
3 o and bonded thereto or otherwise entangled such that they are not a part
of the desired pile density.
2
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
US Patent No. 5,470,629 to Mokhtar et al. describes making
pile "tuftstrings" where each tuftstring is made by wrapping yarn around a
mandrel on which a support strand is translated. As the support strand
moves, it transports "wraps" of yarn to an ultrasonic welder which
connects the wraps to the support strand. The bonded wraps are further
transported to a slitter station which cuts the wraps and thereby forms the
tuftstring. The tuftstring includes two rows of upstanding legs or tufts
which are attached at their bases to the support strand. The yarn of
Mokhtar et al. is a multifilament, crimped, bulky yarn that is made
Zo preferably of a thermoplastic polymer, such as nylon or polypropylene.
The support strand is likewise preferably a thermoplastic polymer so that,
when passed under the ultrasonic welder, the yarn and support strand
melt to form a bond therebetween.
It is desirable to have an elongated pile sub-assembly that has
15 a high "tuft-lock" value, controlled wicking and vertical alignment. There
is
also a need for a low-cost elongated pile sub-assembly, containing
bundles of fibers arranged to provide a high density, that can be made by
a simple, inexpensive method, and is designed to be packaged, or used
directly as a feed material for making a brush or a pile/bristle surface
2o structure. There is also a need for a strong, reliable elongated pile sub-
assembly that can be packaged and handled in a fabrication process. It is
also desirable to have a guide apparatus to bond the elongated pile sub-
assembly to a substrate.
25 SUMMARY OF THE INVENTION
The elongated pile sub-assembly of this invention includes a
continuous length support beam having a longitudinal axis, a uniform or
substantially uniform cross-sectional size and shape, a peripheral surface,
3 o a reference plane tangent to or coincident with a location on the surface
of
the support beam, and a plurality of bundles of filaments secured to the
support beam. The filament bundles have long bundle segment ends
opposite the short bundle segment ends. The filaments on an end of at
3
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
least one bundle (e.g. the long bundle segment ends) define a pile-
forming tuft. There is a region in each bundle in which the filaments are
densely-packed together and are generally bonded together, and the
bundle is preferably secured to the support beam at the location of the
densely-packed region.
Briefly stated, and in accordance with one aspect of the
present invention, there is provided an elongated pile sub-assembly
comprising: an elongated beam having a longitudinal axis, a substantially
uniform cross-sectional size and shape, and a peripheral surface; and at
Zo least one bundle of filaments being secured to the peripheral surfiace of
the beam; wherein the at least one bundle is secured to the beam at a
location along the length of the bundle that divides the length into a longer
bundle segment and a shorter bundle segment on either side of the
longitudinal axis, said longer bundle segment defining a pile-forming tuft.
Pursuant to another aspect of the present invention, there is a
brush comprising: a first brush body member, and at least one elongated
pile sub-assembly secured to the first brush body member.
Pursuant to another aspect of the present invention, there is a
pile or bristle surface structure comprising: a substrate, and an elongated
2 o pile sub-assembly secured to the substrate.
Pursuant to another aspect of the present invention, there is a
guide, comprising: a groove for holding an at least one elongated pile sub-
assembly according to any one of claims 1-19, having an at least one
short bundle segment end, said short bundle segment end extending out
of the same side of the guide as the groove, and means for attaching the
at least one shorter bundle segment end to a substrate, wherein the guide
is used to join the at least one elongated pile sub-assembly to said
substrate.
Pursuant to another aspect of the present invention, there is a
3 o method for joining an elongated pile sub-assembly to a substrate using a
guide, comprising: guiding the elongated pile sub-assembly through a
groove with the shorter bundle segment extending externally beyond the
groove in said guide; applying a bonding means to at least one of the
substrate and the shorter bundle segment; moving the substrate and the
shorter bundle segment into bonding contact with one another; and
4
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
securing the shorter bundle segment extending beyond the groove to the
substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following
detailed description, taken in connection with the accompanying drawings,
in which:
so Fig. 1A shows the prior art of a conventional "U" shaped
tuftstring;
Figs. 1 B and 1 C are elevational end views of the prior art
showing visible defects resulting from "U" shaped tuftstring rotation;
Fig. 2B shows a rooted tuftstring of the present invention;
Figs. 2A, 3A, and 4 are elevational end views of the elongated
pile sub-assembly of the present invention showing different "root" end
penetration;
Fig. 3B shows elevational end views of a plurality of rooted
tuftstrings shown in Fig. 3A with the entanglement of the rooted filaments;
2 o Fig. 5A is a perspective view of an elongated pile sub-
assembly of the present invention;
Fig. 5B is a prior art perspective view of an elongated "U"
shaped tuftstring; .
Fig. 6 is a diagram showing one way to measure the diameter
of a pile yarn;
Fig. 7 is a simplified representation of a section along the
center of an elongated pile sub-assembly support beam showing tufts
bonded to the beam in a single layer with the "roots" extending below;
Fig. 8 is a simplified representation of a section along the
3 o center of a rooted tuftstring support beam showing bundles bonded to the
beam in an overlapping relationship;
Fig. 9A is a diagrammatic view of a simple process for making
the elongated pile article of the present invention;
Fig. 9B is an end view of Fig. 9A showing a second slitter;
Fig. 10 is a side elevational view of a paint roller pile assembly
using the present invention;
5
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
Fig. 11 is an end view of the paint roller of Fig. 10;
Fig. 12 is an end elevational view of an embodiment of a
plurality of elongated pile sub-assemblies;
Fig. 13 is an end elevational view of an embodiment of an
elongated pile sub-assembly bonded using an ultrasonic weld;
Fig. 14 is an end elevational view of a plurality of elongated pile
sub-assemblies of the present invention attached via adhesive pile tape to
a core;
Fig. 15 is a diagramatic illustration of a method of making a pile
z o or bristle surface structure from elongated pile sub-assemblies of this
invention;
Fig. 16 is a schematic illustration of a guide used in attaching
or bonding elongated pile sub-assemblies of the present invention to a
backing substrate or bonding material;
Fig. 17 is a schematic illustration of an elongated pile sub-
assembly guide for bonding with flexible materials; and
Fig. 1 ~A and Fig. 18B show elevational views of two
embodiments of an ultrasonic horn used for bonding in the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
Definition of Terms
The following definitions are provided as reference in
2 ~ accordance with how they are used in the context of this specification and
the accompanying claims:
1. Beam or Base String: A strand, string or cord composed of one or
more materials and having one or more separate structural
3 o components, each having its own defined and identifiable shape.
The beam or base string provides connectivity and support to tufts
attached thereto.
2. Bristle: A short stiff fiber segment natural or man-made generally
3 s referred to as in diameters measured in thousandths of an inch.
6
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
3. BCF or BCF Yarn: bulk continuous filament yarn; a textured
continuous-filament yarn, generally used either as a pile yarn in
carpets or for upholstery fabrics.
4. Tuftstring: A beam having attached to it at least one segment of
yarn consisting of one or more filaments each having a diameter
such that the diameter is reported in units of denier rather than
thousandths of an inch (mils).
Zo 5. Rooted Tuftstring or Elongated Pile Sub-Assembly: A Tuftstring
where the beam or base string divides the long bundle segments
from the short bundles segments. The short bundle segments also
called "roots" are the non-bonded yarn fiber that attaches the
tuftstring to substrates (i.e. other articles or base materials). The
15 long bundle segments are the non-bonded yarn fiber end that forms
the pile or bristle end of the tuftstring.
6. Denier: The mass in grams of 9000 meters of a fiber, filament, or
yarn.
7. Fiber: Textile raw material, generally characterized by flexibility,
2 o fineness arid high ratio of length to thickness.
5. Filament: A fiber of indefinite length.
9. Filament Yarn: Normally continuous filament. A yarn composed of
one or more filaments measured in denier units that run essentially
the whole length of the yarn.
25 10. Yarn: A product of substantial length and relatively small cross-
section consisting of fibers and/or filaments with or without twist.
The rooted tuftstring of this invention may be understood from
a general description of a method by which it may be produced. This
3 o method involves: feeding a continuous length of a bundle of filaments
under tension along the center of rotation of an eccentric guide; rotating
the guide to wrap the bundle of filaments around a support having a
plurality of elongated ridges to form a succession of wraps or flights of the
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
continuous length of a bundle of filaments that envelope the support;
feeding a continuous strand of material along at least one of the ridges on
the support, between the support and the flights of the bundle of filaments
formed by the step of wrapping, to provide a beam; bonding the filaments
in the bundle to each other and securing the bundle of filaments to the
beam; cutting the flights of the bundle of filaments to form an elongated
pile sub-assembly; and forwarding the elongated pile sub-assembly for
further processing. Reference is made to US Patent No. 5,547,732, WO
99/29949, and 5,498,459 whose contents are herein incorporated by
so reference as examples of the above method of forming a "U" shaped
tuftstring. In the present invention, however, the above prior art references
are differentiated from the present invention in the cutting step to produce
the rooted tuftstring. A distinguishing difference, in the present invention,
is the position of the rotating slitter knives relative to the bonded beam
(e.g. base string). In the above referenced patents, the slitters are
positioned so as to form two tufts of substantially equal length from one
continuous yarn segment. In the present invention, the slitters, or the
bonding position of the beam, or both are repositioned so as to produce a
tuftstring with a first bundle of filaments segment for use as the pile
2 o surface and a second bundle of filaments segment for use in anchoring
the tuftstring to a fabric or other support structure, such that the first
segment is generally longer than the second segment. (See Figures 9A
and 9B). The above references are examples of machine methods
capable of producing tuftstrings with the modified cutting step but are not
all-inclusive. There are a variety of machine methods that are applicable
to producing the rooted tuftstring of the present invention.
In the "U" shaped tuftstring (see Fig. 1A) the bundle of
filaments is cut such that the base string 101 is substantially equidistant
from the cut end of each bundle segment of the tuftstring 108. In Figure
1A, the "U" shaped tuftstring 108 has an equal bundle segment length
109a and 109b on either side of the base string 101. The tuftstring 108 is
bonded to the adhesive backing 107 at the six o'clock position 101 a. A
disadvantage of the "U" shaped tuftstring approach is that the bundle
segment lengths 109a and 109b can appear to be uneven when
3 5 assembled with other "U" shaped tuftstrings (See 1 B and 1 C). This can
occur in a variety of ways. For example, the base portion of the "U"
s
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
shaped tuftstring may roll or rotate as it is guided and secured to the
backing. More friction on one bundle segment 109b than on bundle
segment 109a, for example, would generate a torque and cause the "U"
shaped tuftstring to rotate counter clockwise as shown by arrow 103a (see
Fig. 1 B). Another cause can be attributed to an uneven substrate surface
such as when a reinforcement fiber is present and generates a ridgeline
105a on the surface. Referring to Fig. 1 C, when first side 109a of the "U"
shaped tuftstring contacts the substrate surface before second side 109b,
a torque force is again established when the velocity or motion is normal
z o to the plane of the substrate and can cause the tuftstring to rotate or
lean.
The leaning effect shown in Fig. 1 C, can also cause a space 132 between
the tufts which creates an undesirable spacing defect or at least causes
density variations in the finished pile.
The present invention (see Figures 2A, 2B, 3A, and 4) utilizes
s5 a modified tuftstring that improves the bond strength between the
tuftstring
and the substrate used to bind multiple tuftstrings together (for example,
as in a carpet), especially when adhesives are used as the bonding agent.
Thus, eliminating the need in the present invention (e.g. one long bundle
of fibers segment side 126 and one short bundle of fibers segment side
20 127,128,129) to fold the yarn tufts into a conventional "U" formation. The
long bundle segments 126 are arranged together as a continuous row of
long bundle segments in the proper orientation for functional value, while
the short bundle segments 127, 128, or 129 are used to anchor the
elongated pile sub-assemblies 125 to the backing substrate with the aid of
2s an adhesive or other means, such as ultrasonic bonding or solvent
bonding.
In the present invention, the yarn used in the elongated pile
sub-assembly 125 (see Fig. 2A) is a multifilament strand where the
filaments are typically "connected" to one another. The filaments are
30 "connected" in that they may be twisted at a level of at least about 1
turn/inch to provide filament crossovers that enhance bonding (especially
ultrasonic bonding), or the filaments may be interlaced to provide
crossovers. The yarn may also comprise two or more strands of
multifilaments that are ply-twisted together. The ply-twisting may be a
35 "true" S or Z strand and ply twist, or a reverse twist where the S and Z
strand and ply twist alternate and there is a bond in the ply and strand
9
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
twist reversal. Preferably the reverse twisted yarn has a bond in the plied
yarn before reversing the twist, as described in US Patent No. 5,012,636.
One such yarn is preferably made from crimped, bulky, heat-treated
filaments and is commonly used as carpet yarns. The filaments of the
yarn may have a variety of cross-sections which may be hollow and
contain antistatic agents or the like. The yarn may have a finish applied
that aids in ultrasonic bonding. The yarn may in certain preferred
embodiments be a multifilament, crimped, bulky, ply-twisted yarn that has
been heat set to retain the ply-twist.
to In other applications where a velour surface is preferred,
such as in automotive flooring and paint rollers, another type of yarn is
preferred. Such a yarn includes one in which the multifilaments of the
BCF yarn are loosely entangled and are not heat treated. For automotive
or other transportation use, the rooted tuftstring (i.e. elongated pile sub-
assembly) is preferably made of BCF singles yarn, that is not twisted, ply-
twisted, or otherwise entangled to form individual long bundle segments
as described in WO 99/29949.
When using ultrasonic bonding means to form the rooted
tuftstring, the yarn, (preferably made from a thermoplastic polymer having
2 o the same composition as the beam,) achieves high bond strength of the
yarn bundles to the beam. In some ultrasonic bonding applications, the
yarn and the beam can be of different compositions and still achieve
adequate bonding between the two. One such example is a nylon yarn
bonded to a polypropylene beam. It is further noted that in bonding
methods other than ultrasonic bonding, using the same composition for
beam and yarn provide high bond strength and avoid the need for
adhesives. However, adequate bonding of different compositions for the
yarn and beam in bonding methods other than ultrasonic are also
adequate.
3 o When using an adhesive method to bond the yarn to the
beam, the composition of the yarn and the beam is selected according to
the range of suitable materials the adhesive can bond with or, the
adhesive is selected according to the selection of yarn and beam
composition. It is important that the bond between the yarn and the beam
3 5 be adequate to deliver the yarn to the support structure without loss of
yarn segments or individual fibers from a yarn segment. Once the short
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
segment fibers are bonded to the substrate, the bond strength between
the beam and the yarn bundles becomes less significant.
In the present invention, the yarn is typically a thermoplastic
polymer such as a polyamide, a polyolefin such as polyethylene or
polypropylene, a polyester, a fluoropolymer, polyurethane,
polyvinylchloride, polyvinylidene chloride, or a styrenic polymer or
copolymer, including mixtures of two or more thereof, and the. like.
Polypropylene; or a polyamide such as nylon 6; nylon 11; nylon 6,6;
nylon 6,10; nylon 10,10; and nylon 6,12 is preferred. The yarn may
so alternatively be a poly (aryletherketone) or a polyaramid or meta-aramid
that is bondable with solvents, ultrasonics, or heat.
The beam useful in the elongated pile sub-assembly may
have a variety of cross-sectional shapes, such as square, rectangular,
elliptical, oblong, round, triangular, multi-lobal, flat ribbon-like, etc. The
beam must be bondable to the yarn and have sufficient elongational
stability so the bonds are not over-stressed due to stretching of the beam
or its tensile strength exceeded. The beam must provide sufficient
stability to the pile sub-assembly such that it can be handled for its
intended use, such as manufacturing a brush or manufacturing floor
2 o covering articles, such as a carpet or rug. The beam may be a
monofilament, a composite structure, a sheath/core structure, a reinforced
structure, or a twisted multifilament structure. The beam is preferably
made from a thermoplastic polymer so the yarn beam can be bonded
without use of adhesives. The beam is more preferably a polymer having
a molecular structure oriented in the elongated direction, and having a low
dimensional change in the direction of orientation due to moisture gain or
loss or modest temperature changes. One material for use as the support
beam is a monofilament nylon polymer, such as Tynex~ made by E. I. du
Pont
3 o de Nemours and Company. Other materials for use as the support beam
include polypropylene and polyethylene. In some applications, one or
more of the polymers named above can be combined, such as in co-
extrusion to form a bi-component beam.
Filament production may be accomplished by the use of an
extruder, many varieties of which, such as a twin-screw extruder, are
available from manufacturers such as Werner and Pfleiderer. A polymer
11
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
in the form of granules is fed from a feeder unit into the extruder either
volumetrically or gravimetrically. A slip agent is fed from a separate
feeder into the extruder through a side-arm port, and is blended with the
polymer in the extruder at a temperature of 150-2~5°C. Alternatively,
the
slip agent can be pre-compounded or pre-blended with the polymer so
that a separate feed system is not required. The polymer and slip agent
are mixed as a melt in the extruder, and the resulting composition is then
metered to a spin pack having a die plate. The composition is filtered,
and filaments of various shapes and sizes are produced by extrusion
to through the holes. in the die plate.
Similar to the support beam discussed above, the filaments
from which the bundle of filaments is prepared may have a variety of
cross-sectional shapes, as determined, for example, by the shape of the
die plate orifice when production is by extrusion. The shapes include but
are not limited to round, oval, rectangular, triangular, or the shape of any
regular polygon; or the filament or beam (discussed above) may be an
irregular, non-circular shape. Additionally, the filament or beam may be
solid, hollow or contain multiple longitudinal voids in its cross sections.
Each run of an extruder can produce any combination of cross-sectional
2 o shapes by using a die plate with various shaped holes. Filaments or
beams of one or more diameters may be made at the same time by
varying the size of the holes in the die plate. Alternatively, the filament
and/or beam used in this invention may be produced by solution spinning.
Another aspect of this invention involves the use of a
filament and/or beam having a sheath/core construction. The sheath
surrounds the core in a coaxial or concentric configuration. The polymer
used in the core and the sheath may be the same or different. When
dissimilar polymers are used, the properties of the polymers must be such
that they can be co-extruded, drawn to diameter and wound onto spools.
3 o Nylon 6,6 is preferred as a sheath material. A sheath/core filament or
beam is typically produced by coextrusion using two extruders sharing a
common spin pack. The polymer used to make the core is channeled
from a first extruder to the center of the spin plate holes, and the
composition used to make the sheath is channeled from a second
3 5 extruder to the outside of the spin plate holes.
12
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
A sheath/core filament of yarn, or a beam in filament form,
which is produced from more than one source of flowable polymer or
polymeric composition, as described above, may be distinguished from a
filament that is produced from a single source of flowable polymeric
composition. Such a single-source filament may be referred to as a
single composition monofilament. For a beam, the filament used in the
present invention may be either a multi-component or a single component
monofilament, with a single component monofilament being preferred.
so A filament for use in the bundle of filaments in this invention
has a diameter, or maximum cross-sectional dimension, as determined by
the diameter of the smallest circle in which it is circumscribed, of about
one or more, preferably about two or more, and most preferably about 2.5
or more, and yet about 15 or less, preferably about 10 or less, and more
15 preferably about 5 or less, mils. (A mil is 0.025 mm.)
A filament or beam for use in this invention may be prepared
from a polymeric composition as described above containing typical
additives such as fillers, colorants, stabilizers, plasticizers or anti-
oxidants,
or a mixture of more than one thereof; or may be prepared with a surface
2 o coating.
Reference is now made to Figures 2A~4 which show
different end views and encapsulation embodiments of the "root" end of
an elongated pile sub-assembly, or rooted tuftstring 125 of the present
invention. Figure 2 shows an end elevational view of an elongated pile
25 sub-assembly with the short filament bundle segment 127 penetrating the
adhesive 117 and backing substrate 115. Figure 3A shows an end
elevational view of an elongated pile sub-assembly with the short filament
bundle segment 127 having a flared penetration 128 of the adhesive 117
and the backing substrate 115. Figure 4 shows an end elevational view of
3 o an elongated pile sub-assembly with the short filament bundle segment
127 having surface flaring 129 in the adhesive 117. In Figs. 2A~4 the
short filament bundle fibers are totally encapsulated for a strong anchoring
of the elongated pile assembly 125. Another variation, not shown, is
where all the roots 127 of Figure 2 lay horizontally to one side.
35 With continuing reference to Figs. 2A~4, the ultimate
position of the roots of the tuftstring is mostly dependent on the
13
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
characteristics of the substrate and the stiffness of the root filaments. An
open, non-woven substrate would easily permit the roots to penetrate the
fabric structure without much deflection of the roots as shown in Figure
2A. Tightly woven fabrics ofFer more resistance and deflect more of the
roots upon entry into the fabric as depicted in Figure 3A and 3B. A highly
dense non-woven fabric, like Tyvek~ or a solid sheet, such as an
extruded thermoplastic structure would prevent penetration by the filament
roots into the substrate structure causing complete deflection 129 of the
short segment fibers 127 as shown in Figure 4.
Referring now to Figure 5A which shows a plurality of
bundles of filaments 154, as yarn that has been secured to a support
beam 119 at a location 73 on the peripheral surface thereof. The longer
bundle segment 126 of the elongated pile sub-assembly 125 defines a
pile-forming tuft. The shorter bundle segment 127 of the elongated pile
sub-assembly 125 defines the root forming tuft.
Referring now to Figure 2A which shows the elongated pile
sub-assembly 125. The bundle of filaments 154 is bonded to the beam
119 to form the elongated pile sub-assembly. The bundles of filaments
154 has, along its length, a densely-packed region 162 where the
2 o filaments are generally bonded together, and which is the location where
the bundle is secured to the support beam 119.
Referring again to Figure 5A, a support beam 119 has a
uniform, or substantially uniform, cross-sectional size and shape, and a
peripheral surface 133. The densely-packed region 162 (Figs. 2A~4)
along the length of the elongated pile sub-assembly 154 where the
filaments are bonded together is secured to the peripheral surface 133 of
the support beam 119 parallel and adjacent thereto. The bundle of
filaments 154 is secured to the peripheral surface 133 (perpendicular to
the reference plane 71 ) of the beam across all, or across a substantial
3 o portion of, the densely-packed region 162. Contained within the bundle
of filaments 154 are filaments that are substantially linear, and thus have
opposing ends 202 and 204. The opposing ends of the filaments define
a length of the bundle. The bundle 154 is secured to the beam at a
location along the length of the bundle that divides the length into a longer
bundle segment 126, which has a longer length, and a shorter bundle
14
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
segment 127, which has a shorter length, on either side of the longitudinal
axis 140 of the beam 119.
The longer bundle segment 126 contains longer filament
segments, and the length of the longer bundle segment is measured from
the location that divides the filament bundle 154 into longer and shorter
bundle segments to the end 202 of the longer filament segment contained
in the longer bundle segment. The longer bundle segment 126 is pile-
forming at the cut ends 202 of the longer filament segments. The shorter
bundle segment 127, contains shorter filament segments, and the length
to of the shorter bundle segment is measured from the location that divides
the filament bundle into longer and shorter bundle segments to the end
204 of the shorter filament segments. The usable portion of the longer
bundle segment 126 and the shorter bundle segment 127 are on opposite
sides of the densely packed region of the filament bundle 125. The
shorter filament segments define "roots" that have substantial utility in
anchoring the tuft particularly when the pile sub-assembly is used to make
a brush, pile surface structure or other articles, as described herein.
The length of the shorter bundle segment 127 (Fig. 2A) is
preferably about 90 percent or less than the length of the longer bundle
2 o segment 126. In other embodiments, however, the length of the shorter
bundle segment may, as desired, be about 75 percent or less, about 50
percent or less, about 25 percent or less, about 10 percent or less, or
about 5 percent or less, than the length of the longer bundle segment.
The length of the shorter bundle segment preferably exceeds about 10
percent of the width of the beam. For example, if the beam width is 200
mil then the roots need to be longer than 20 mils. (It is further noted that
the longer the short bundle segment 127 when attached to the substrate,
the more secure the anchoring of the elongated pile sub-assembly 125).
The width of the beam is defined as the smallest of the following
3 o quantities: (i) the distance across the cross-sectional area of the beam
74,
as shown, for example, in Fig. 5A, measured through and perpendicular to
the longitudinal axis of the beam and parallel to the reference plane 71;
(ii) the diameter of the smallest circle that completely circumscribes the
cross-sectional area of the beam; or (iii) in the case of a cross-sectional
area of the beam that is a true rectangle, the longer of the two dimensions
of the rectangle. In further embodiments, however, the length of the
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
shorter bundle segment may, as desired, exceed about 55%, about 60%,
about 75%, or about 100% of the width of the beam.
Six test samples of rooted tuftstring were tested for
anchoring strength using an Instron (Model #1125). The rooted tuftstring
samples were 1.00" long having a short segment length of 0.090 inches
and a long segment length of 0.265 inches. Two test cells, repeatedly
used, were fabricated having the following cavity dimensions: 1.00" long
by 0.185" wide and 0.25" deep to receive an adhesive. A hot melt
adhesive of Profax Polypropylene PF611 CT distributed by the H. A.
1o Hanna Company was used. The test cell was heated and filled with the
Profax Polypropylene PF611 CT adhesive. The rooted tuftstring sample
was placed into the test cell such that the short segment fibers only were
subsurface in the adhesive melt. The rooted tuftstring, adhesive and cell
were then allowed to cool to room temperature before testing for
anchoring strength. The Instron clamping device was fastened to the test
cell and another to the long segment fibers of the rooted tuftstring. The
Instron test instrument was used to detect the peak force applied to the
clamps at the moment of failure of the roots. The goal of these tests was
for the rooted tuftstrings to have an anchor strength greater than 15 Ibs.
2 o In test after test, there was no failure observed of the bond between the
short segment fibers and the solid adhesive resin within the test cell. The
type of failures observed were: 1 ) between the adhesive and the test cell
walls which were the most common failures; and 2) the remaining failures
were the yarn fibers that failed in the vicinity of the bond between the yarn
fibers and the beam. All failures of the adhesive to the test cell and of the
yarn fibers occurred at tensions exceeding 45 pounds. These results far
exceeded the minimum desired goal of 15 pounds.
It is important to realize that the "roots" of each yarn bundle
are in a three dimensional space when anchored into a substrate. For
3 o example, Figure 4 shows the roots spread to the left or right of the
bundle
vertical center in this end view. While this orientation 129 of the short
bundle segments 127 can occur, they are more likely spread 360 degrees
from the vertical center of the bundle 125 within a plane parallel to and a
plane below the reference plane 71 of Figure 5A. In Figures 2B and 3A,
the roots are spread in a cone shape below the reference plane 71 (Figure
5A), each having a center vertical axis generally tangent to or coincident
16
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
with the yarn bundle side vertical peripheral surFace of the beam. Figure
2B is a narrow cone, while Figure 3A is more hemispherical.
In an embodiment of the present invention, Fig. 5A shows
the elongated pile sub-assembly in which the bundle of filaments is
secured to the support beam 119, which may be accomplished by
ultrasonic bonding or other means. The filaments of the short bundle
segment 127 are used as the anchoring point of the elongated pile sub-
assembly 125. By comparison, the "U" shaped tuftstring of the prior art,
utilizes the dense portion 101 a (see Fig. 1 A) of the filament bundle and
1o the bond line formed between the support strand and the yarn bundles as
the anchoring surface. This area has the characteristics of a solid mass,
and as such, the only surfaces available for an adhesive to connect with,
are the outer peripheral surfaces of the yarn/strand mass. This is a limiting
characteristic of the prior "U" shaped art. By contrast, the short bundle
segments 127 (Fig. 2B) of the present invention, have substantial surface
area due to the "roots" (e.g. fibers of the short bundle segments) it
provides to anchor the filament bundle in an adhesive media 117. In the
present invention, the roots are filament segments that are continuous
with and extending in the opposite direction of the pile forming filament
2 o segments. The proximal end of the short filament segments or roots are
bonded to the beam and are thus fixed in position and have limited
surface area in that regard. However, the remaining length of the short
filament segment roots can and do provide considerable surface area. In
the simplest case where the cross-section of the filaments is round, the
surface area is simply the surface area of a cylinder.
Comparison by example of the surface area of the "U"
shaped tuftstring to that of a rooted tuftstring of the present invention,
clearly shows the benefit of the present invention. For example, when
using a 28 mil beam and a 1500 denier, two-ply yarn bonded to the beam
3 o to form both a "U" shaped tuftstring and a rooted tuftstring, the adhesive
bonding surface area of the "U" shaped tuftstring is 0.060 square inches
per inch of tuftstring whereas for a rooted tuftstring, having a 0.063 inch
length of short segment fibers and eleven (11 ) tufts per inch, it is found
that the surface area is 0.864 square inches per inch of tuftstring. This is
3 5 a 1,340 percent increase in available surface area for the adhesive to
bond with.
17
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
In addition, these unconstrained distal filament ends of the
short segment fibers can interact and entangle 121 with the (fibrous)
structure of the substrate as shown in Figure 3B for added anchoring
strength. The fibrous "roots" of the present invention are encapsulated
and mechanically locked into the adhesive media when it freezes. This
mechanical bond replaces the need for a strong chemical or thermal bond
to anchor the tuftstring to a support substrate and therefore greatly
expands the opportunity to use lower cost, and environmentally friendly
adhesives.
so Referring to Figs. 2B~4, the filaments of the short bundle
segment 127 act as a wick and draws the adhesive into the void spaces
between the filaments generating a matrix structure such as found in resin
composite structures. The dense portion of the filament 162 limits the
travel of the adhesive from migrating up into the long bundle segment 126
15 by forming a barrier zone. In this embodiment, the opposing ends 202,
204 of the filaments define a length of the bundle. This bundle has
longer and shorter bundle segments, characteristics related to the length
of the longer and shorter bundle segments, and varied orientation 128,
129 of the shorter filament segments when attached to a support
2 o substrate, as described above.
Where yarns with strong interconnections among the
filaments are used, it may be preferable to "comb out" the short segment
portion of the rooted tuftstring so that filament to filament entanglement is
minimized to permit the short segment fibers to better disperse into the
25 adhesive and support substrate.
A further characteristic of the bundle of filaments utilized in
the elongated pile sub-assembly of this invention is that (1 ) at least one
bundle is divided into (a) a first segment, comprising first filament
segments, on one side of the location at which the bundle is secured to
the beam, having a first stiffness, and (b) a second segment, comprising
second filament segments, on the other side of said location, having a
second stiffness. The change in stiffness of a filament is proportional to
the fourth power of the effective cross-sectional area and to a third power
of the length. Thus for a given diameter, the relative stiffness will decrease
35 by 87.5% when the unrestrained length is doubled, assuming no
interactions with adjacent filaments. Therefore the stiffness of the short
18
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
segment bundle can be slightly higher or orders of magnitude stiffer than
the longer segment bundles depending solely on the ratio of length.
Depending upon the product to be made from rooted
tuftstring, the length of the short segment is. selected based on these
characteristics such as stiffness and anchoring strength to the substrate.
Longer short segment fibers have reduced stiffness and therefore will be
more likely to "mat" down such as in Figure 4. Shorter short segment
fibers will be stiffer and have a greater potential for puncturing the surface
plane of the support substrate such as shown in Figure 2. As expressed
so earlier, the denier of the fiber filaments also influences the extent to
which
fibers will puncture or penetrate into the substrate. Longer short segment
fibers may entangle with adjacent rooted tuftstrings and thus, share
bonding force with adjacent tuftstrings (see Fig. 3B). However, there is a
limit to the desired length of the short segment fibers. At some length,
15 determined by composition, cross-section, shape, etc., the bond strength
of the roots can exceed the failure strength of the fiber in the dense
portion of the rooted tuftstring. Thus, there is no value in increasing the
length of the roots unless the purpose is to strengthen the substrate
material. Cost is also a consideration here. As short segment fiber length
2 o is increased, the raw material cost increases as well. An optimum length
can be selected based on the material chosen and testing that ensures
adequate anchoring strength in a desired cost range.
In a preferred position the beam is positioned between the
supply yarn and the mandrel as the supply yarn is wrapped around the
25 mandrel (as described in 5,472,762, incorporated by reference above). In
an alternative embodiment, however, the beam can be secured to the
wraps or flights of yarn such that the wraps are positioned between the
beam 119 and the mandrel. The characteristics of the densely packed,
bonded region remain the same as described with reference to Fig. 2A.
3 o The unique geometry of the pile sub-assembly is described
below, and is presented "normalized" by expressing dimensional features
as a ratio to the free yarn bundle diameter. The yarn bundle diameter is
a parameter that is related to the ability of the yarn to cover a surface in
an efficient manner in a fabricated article. For repeatability in measuring,
35 the yarn bundle diameter is the untensioned average diameter of a one
inch long straightened section of a longer bundle segment remote from
19
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
the cut ends to avoid the ambiguity that flaring of the cut ends may cause
when making a measurement. The yarn bundle diameter can be
repeatably measured using a microscope with grid lines or an optical
comparator, such as a "Qualifier 30" made by Opticom. Figure 6 shows a
view of the yarn on the Qualifier 30. A one inch piece of straight yarn with
no cut end flare (which may be straightened with very low tension that
does not appreciably compact the yarn) is placed on top of a flat block
181 located in the light path of the comparator. At a 20x magnification,
the sample 182 is aligned with a horizontal line 184 on the comparator
1 o screen that is passed through the peaks and valleys along the edge of the
sample to define an average edge location. The line is moved to the
opposite average edge of the yarn at position 186 and the distance moved
188 is recorded as the average "diameter" of the one inch long sample.
This may be repeated with several samples of the supply yarn to further
s5 average the "diameter". In the case where there are different diameter
bundles along the beam, the bundle diameter would be the average
diameter of all the different bundle diameters along a representative
length where the pattern of different diameters repeats. The bundle
diameter of a yarn may be about 0.114 inches, and is preferably between
2 0 0.020 inches and 0.150 inches.
As previously noted the present invention is applicable to
both singles and twisted/plied yarns. The singles yarn is not a twisted or
highly entangled bundle of fibers. There is a "leveling" of the loosely
entangled filaments of the singles yarn by the ultrasonic horn in the
25 bonding process which tends to average and redistribute the yarn
filaments. The relationship of the bundles to each other along the support
beam is defined by the pitch for twisted yarn, which is the distance
between bundles along the support beam, by the width of the support
beam, and by the bundle diameter. Singles yarn has no distinguishable
3 o P/D ratio.
The bundle pitch/bundle diameter ratio (P/D ratio) describes
the distance between adjacent bundles of yarn (pitch) laid along a length
of support beam compared to the yarn bundle diameter. The unique
process of the invention allows the product to have a much denser
35 distribution of bundles along the beam than other elongated pile articles
taught in the art. When the yarn is wound onto the support beam there
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
are at least three methods of achieving a high density of bundles on the
beam: 1 ) apply enough tension to the yarn bundle that the diameter necks
down such that when the necked down yarns are laid adjacently abutting
each other along the beam, the pitch is less than the free untensioned
bundle diameter; 2) wind multiple layers of yarn bundles on the beam;
and 3) a combination of the first two.
In contrast to the "U" shaped tuftstring of the prior art, the
P/D ratio for the rooted tuftstring will generally be two times (2X) that of
the "U" shaped tuftstring to achieve the same pile density. Since the
to second shorter segment of the fiber bundle is used to attach the rooted
tuftstring to a support substrate, it is not available as pile for the exposed
surFace as is the case with the "U" shaped tuftstring. Doubling the pitch to
achieve the desired density provides a corresponding density of roots to
ensure a high anchoring strength for the rooted tuftstring.
The P/D ratio can be further appreciated referring to Figures
7 and 8. The bundles of yarn are bonded to the opposite side of the
beam 119 shown as simplified tufts, 205a, 206a, and 208a. The simplified
tufts are bonded to the beam at the densely packed region 162. The
simplified rooted ends 205b, 206b, and 208b are shown extending past
2o the beam. The pitch "P" of the bundles along the beam 119 is best
understood referring to Fig. 7 and looking at the abutted center-to-center
spacing or pitch 210 between the dense bonded portions of adjacent
bundles. It is preferable to measure pitch here instead of at the end of the
tuft since the tuft ends are somewhat free to move about. The diameter
of the bundle "D" is represented by the distance across an untensioned
bundle or diameter 75. The pitch may have to be averaged along a one
inch length to get a representative number as some local variations are to
be expected.
Figure 8 shows how the pitch is determined when there are
3 o multiple layers of bundles along the beam 119 and the simplified root end
portions of the bundle bonds may overlap one another. Bundle tufts,
such as 205a, 206a, 214a, and 215a are shown above beam 119 and the
overlapped dense rooted end portions of the bundle bonds for these
bundles are shown below the beam 119, as 205b, 206b, 214b, and 215b,
respectively. The pitch "P" is the distance between adjacent dense
portions 162 of bundles successively placed along the beam at pitch 210.
21
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
Once again, the number of bundle bonds along a one inch section may
need to be averaged to get a representative number for "P". In the case
where there are different diameter bundles along the beam, perhaps
causing the pitch to vary considerably, the pitch would be an average
represented by the reciprocal of the number of bundles per a
representative length where the pattern of different diameters repeats.
The bundle pitch may be about 0.033 inches, and is preferably-between
about 0.015 and 0.150. The PlD ratio may be about 0.30, and is
preferably between about 0.1 and 7.5.
z o The width of the support beam is an important parameter in
the present invention for the following reasons: 1 ) it must have an outer
perimeter sufficient in size to enable the use of the rooted tuftstring guide
assembly (Fig. 16 and 17); and 2) if it is too wide, it may cause the
spacing between adjacent pile sub-assemblies to be excessive such that
a dense array of yarn tufts in a fabricated article cannot be achieved. A
rectangular beam has several advantages and is preferred, though other
cross-sectional shapes can also be useful. The vertical side to which the
yarn filaments are bonded has a larger surface than would for example,
the intersection of the yarn with the tangential surface of a round or oval
2 o beam. The flat top and bottom surfaces are useful in aligning the pile
segments vertically. The flat top of the beam pressed against a slightly
larger flat of the guide assembly works in unison with the slot used to pass
through the long fiber segments to prevent rotation of the rooted tuftstring
as it is processed with a backing substrate. The horizontal flat bottom side
of the beam provides a stable surface as opposed to curved surfaces
such as those of a round or oval beam. The beam width is preferably
0.010 to 0.70 inches.
There is a structural feature, which is important in certain
embodiments, that is related to the manner in which the bundle of
3 o filaments, i.e. yarn, is bonded in the densely packed region 162 to the
beam 119. Continuous filaments within each of the yarn bundles, secured
to the beam and further anchored to the substrate ensures a high
probability of capture and high retention strength for each individual fiber.
However, the higher strength has been found to be to the adhesive and
not to the beam when the appropriate adhesives are selected. In the
present invention the rooted tuftstring, for the reasons stated above,
22
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
minimizes tinting (e.g. loose fibers released from the pile article due to
breakage).
Although the invention has been described above as being
made on an automated device, an alternate embodiment of the invention
can be made by manual means or any other suitable means. Referring
now to Figures 9A and 9B, the supply yarn 20 can be wrapped by hand
around a thin rectangular mandrel 282, for example, having support
beams 119 taped or otherwise held in place along grooves 288 and 290.
After the supply yarn 20 is in place, an ultrasonic horn 292 can be passed
Zo along the yarn, wrapped around grooves 288 and 290, to bond the yarn to
beams 119. The yarn can then be cut by a cutter or slitter 294 at a
predetermined location, proximal to the beam 119, on either side of the
mandrel. For greater efficiency and speed, a slitter may be located above
the beam in groove 288 as shown in Figure 9A and below the beam 119
in groove 290 (see Fig. 9B ) or vice versa. In this manner, two elongated
pile sub-assemblies are easily produced. The first elongated pile-sub-
assembly has short bundle segments relative to groove 288 at the end
above the beam 119 cut by the slitter 294. The long bundle segments of
the rooted tuftstring would be the portion extending from the 119 beam at
2 o groove 288 to the;slitter 293 located below the beam 119 at groove 290 in
Figure 9B. The remaining slit yarn separated from the first elongated pile
sub-assembly forms the second elongated pile sub assembly. If only a
single rooted tuftstring assembly is desired, the second beam and slitter
are omitted along one ridge. The mandrel can have a length 296 that is as
wide as the carpet or article in which the rooted tuftstring is to be used.
To assist in wrapping the yarn, the mandrel may be mounted in a
rotatable chuck and the yarn traversed along the rotating mandrel. A lathe
with a traversing crosshead may be usefully employed to so place the
yarn on the mandrel. In the most general sense, the product can also be
3 o made by laying one precut yarn bundle at a time over the beam and
groove of the mandrel and bonding the bundle so that the wrapping step is
not required.
One method for making an elongated pile sub-assembly of the
present invention comprises: contacting an elongated support beam with a
plurality of bundles of filaments at a location along the perimeter of the
beam; bonding the filaments both, to each other (to form a dense portion
23
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
in the bundle where the filaments are bonded together) and to the beam
at a location along the beam. In the present invention, one method of
bonding the supply yarn to the beam includes an ultrasonic driver such as
a Dukane Corp. model 40A351 power supply capable of 350 watts at 40
KHz, connected to a Dukane Corp. 41 C28 transducer. A Dukane booster
may also be used. Bonding means other than ultrasonic bonding may also
be employed to form the compacted portion of the bundle by securing the
filaments to each other and to the beam. Such means may be solvent
bonding or thermal bonding with, for instance, a hot bar; or some .
to combination of solvent, conductive, and ultrasonic bonding. Or, an
adhesive may be introduced to the location where the bundle is secured to
the beam to form an adhesive bond between the bundle and the beam.
The elongated pile sub-assembly of the invention may be
used to make a fabricated article such as a pile surface structure,
s5 including flooring articles, paint brush rollers, etc. or a brush surface
structure, including toothbrushes, a buffing wheel, etc. A brush may be
made in a variety of configurations, with or without a handle. The
elongated pile sub-assembly of the invention may be used to form a pile
brush face. The pile brush face is the portion of the brush that may be
2 o used, for example, to apply or remove a liquid material, or to alter a
surface by the application or removal of a liquid material. The pile brush
face on a brush may be generally planar in shape, or it may take on other
shapes such as a generally cylindrical shape.
A roller brush, used for an activity such as the application of
25 paint, is a typical example of a brush having a generally cylindrical pile
brush face. The case of a roller brush may be illustrated, for example, as
in Figs. 10 and 11, which show a roller brush 310 having a pile covering
312 as a brush face mounted on a hollow core 314. The hollow core 314
can have any suitable shape, such as cylindrical or oval, depending upon
3 o the application. The pile covering 312 is made of at least one elongated
pile sub-assembly 125 (Fig. 2A) having a support beam 119. The
elongated pile sub-assembly 125 has at least one bundle of yarn secured
to the support beam 119 in which a longer bundle segment 126 defines a
pile-forming tuft as shown in Fig. 2A. The core of a roller brush is
35 typically rotatable about a handle member, not shown.
24
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
With continuing reference to Figures 10 and 11, the pile
covering 312 is formed by securing one or more pile sub-assemblies to
the outer surface of the core 314. In a preferred embodiment, one or
more pile sub-assemblies is wrapped spirally and continuously around the
outer surface of the core 314. Alternatively, however, an elongated pile
sub-assembly may be mounted on the core 314 in an alignment in which
the elongated pile sub-assembly is longitudinal, i.e. parallel to the
centerline axis of the core, or in an alignment in which it describes a circle
about the longitudinal axis along the circumference of the core, or in other
1o variations on any of such alignments as described. Elongated pile sub-
assemblies may be secured to the core in parallel alignment to each
other.
The elongated pile sub-assembly 125 (see Fig. 4) is secured
to the core 314 by any suitable bonding means, including an adhesive
binder applied to the outer surFace of the core 314 immediately prior to a
step of wrapping or otherwise affixing the pile sub-assembly to the core.
Chemical or thermal binding processes may also be employed as well,
however, in addition to other mechanical binders, such as anchors
disposed at opposite ends of the core 314, or a hook and loop locking
2o system. When a thermal binding process is used, it is preferred that the
core and/or the elongated pile sub-assembly, or both, be prepared from a
polymeric material. A portion of the core and/or a portion of the
elongated pile sub-assembly, or a portion of both, may then be softened
by inducing a temperature therein above the melting or glass transition
temperature of the polymeric material. At a fiemperature above melting or
glass transition, the softened polymeric material will flow, creating a zone
of polymer flow. The increased temperature causing polymer flow may
be attained by radiant or conductive heating means, but preferably by
ultrasonic energy. As the polymeric materials from which the core is
3 o made flow and contact the elongated pile sub-assembly, or, as the
polymeric materials, from which the elongated pile sub-assembly is made,
flow and contact the core, or as both results occur, the flowing polymeric
materials become welded and secured at the point of contact after they
cool and resume solid state. As an alternative to increased temperature,
3 5 the zone of polymer flow may be created by the application of a suitable
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
solvent to any of the components that have been fabricated from a
polymeric material.
The core 314 may be prepared from a polymeric material, as
aforesaid, or can be prepared from paper and resin which have adhesive
applied thereto. The core 314 can also include spiral windings of paper
impregnated with resin to which adhesive and fabrics are applied to form a
continuous profile.
In one embodiment, a pile covered fabric is prepared, at
least in part, from a material having a surface that has pores, perforations
so or apertures, or the like, such as a screen, mesh or mesh-like material. In
such an embodiment, the shorter bundle segment 127 of the elongated
pile sub-assembly may be secured to the fabric mesh, and this may be
accomplished by arranging to have the filament segments in the shorter
bundle segments penetrate the mesh-like material. The pile covered
15 fabric is then attached to the core. In other embodiments, however, the
shorter bundle segment of the elongated pile sub-assembly may be
secured to the surface of the core; or the elongated pile sub-assembly
may be secured to the core by a bond between the core and the support
beam, or a bond between the core and portions, or all, of both the shorter
2o bundle segment and the support beam. In these embodiments, the
shorter filament segments may become the point of contact for the
application of adhesive between the substrate and the elongated pile sub-
assembly, forming an adhesive bond between the substrate and the
shorter filament segments, or the shorter filament segments may be the
25 location of, and be contacted with, a zone of polymer flow. The shorter
filament segments act as roots in these embodiments, ensuring a solid
bond between the elongated pile sub-assembly and the substrate.
Referring to Fig. 12, another embodiment of the present
invention is shown in which elongated pile sub-assemblies 424, 426, 428,
3 0 430 are secured to a backing tape 440 by means of hot melt adhesives at
the interface of the tape and the shorter bundle segment and/or the
support beam of each elongated pile sub-assembly. When the elongated
pile assembly is spirally wrapped around a core 442 (Fig. 14), as
described in US Patent 5,547,732, the tape 440 has abutting or adjacent
35 wraps on which the elongated pile sub-assemblies from opposite sides of
the tape are adjacent to each other, i.e, such that, after one flight or wrap
26
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
of the tape, elongated pile sub-assembly 424 is adjacent to elongated pile
sub-assembly 430. (See U.S. Patent 5,547,732). Fig. 13 shows the
bonding of the short segment fibers to the support fabric without the act of
adhesives, such as when ultrasonic energy is used.
Other uses for an elongated pile sub-assembly, according to
the present invention, are to make a pile surface structure. A pile/brush
surface structure is useful for further fabrication into a variety of articles
such as a wall or floor covering, or an airplane or automotive component
for a motor vehicle such as a door panel, a headliner, a floor or trunk mat,
to or seat upholstery. Fig. 15 shows a method to make a pile surface
structure such as carpet using the pile sub-assembly of the invention. A
drum 78 is set up for rotation with a backing material 80 attached, for
instance, by clamping the ends 82 and 84 of the backing in a slot 86 in the
drum. The surface 87 of the backing facing outward would be coated
15 with an adhesive coating, such as a thermoplastic adhesive. An
assembly 88 is set to traverse parallel to the rotational axis of the drum
and carry an elongated pile sub-assembly guide 90 and a hot glue
applicator nozzle 92 to position and meter a thermoplastic or thermoset
adhesive just before or coincident with contact with the elongated pile sub-
2 o assembly and on its center line. Other ways of heating may include a hot
air jet, radiant heater, or flame. The elongated pile sub-assembly 45 could
be supplied from a reel 94 or directly from a mandrel.
With continued reference to Figure 15, as drum 80 is rotated
clockwise, the elongated pile sub-assembly is pulled through guide 90,
25 and pressed against the applied adhesive on the fabric surface 87 of
backing 80. The elongated pile sub-assembly contacts the hot adhesive
and is bonded to the backing. The assembly 88 is synchronized to
traverse along the drum surface and lays down a spiral array of the
elongated pile sub-assembly to the backing surface, with adjacent runs of
3 o the spiral closely spaced such that the just-applied elongated pile sub-
assembly lies close to the previously-applied elongated pile sub-assembly
in the spiral array to define a pile surface structure. After the elongated
pile sub-assembly has been traversed the axial length of the drum
surface, the winding is stopped, and the assembly of the elongated pile
35 sub-assembly and backing is cut along the drum axis, such as at line 96
where the two backing ends come together at slot 86. In the embodiment
27
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
shown, only the elongated pile sub-assembly need be cut at 96 and the
backing ends released to remove the pile structure assembly. The pile
structure assembly can then be removed from the drum and laid flat to
form a pile surface structure or carpet.
The carpet product made by this method has the feature that
the adjacent rows of elongated pile sub-assemblies come from different
elongated portions of the same elongated pile sub-assembly which
eliminates yarn lot variations within the carpet. For instance, a carpet
having about 3.3 oz/ft2 of yarn can be produced by first making an
so elongated pile sub-assembly from 2350 denier, two strands, ply twisted
yarn bonded along the beam at 30 wraps/inch and a 5/8 inch tuft length,
and then mounting the pile sub-assembly on the backing at a pitch of 5
pile sub-assemblies/inch.
In variations of the method, and the product resulting from
the method, shown above, the substrate backing may be selected from
woven or spun-bonded materials. The selection of fabrics such as
Sontara~ by E.I. DuPont de Nemours, Reemay~ by Reemay
Incorporated and Cerex~ from Cerex Advanced Fabrics are particularly
useful since they are made of polymeric material, offered in various
2 o weights and density, and can be used with the various methods for
attaching rooted tuftstrings to them. Although natural fiber fabrics can be
used they are limited to the use of adhesives to bond the rooted tuftstrings
to them. An elongated pile sub-assembly may be secured to a backing
substrate to make a pile surface structure by selecting one of an adhesive,
thermal bonding or solvent bonding. An elongated pile sub-assembly may
be secured to a backing substrate by use of the support beam and/or the
shorter bundle segment, on or beneath the surFace of the backing
substrate, in the same manner as employed for brush construction.
Although the use of adhesive, thermal or solvent bonding means may be
3 o preferred, an elongated pile sub-assembly may alternatively be secured
to a backing substrate by conventional stitching and/or a hook and loop
attachment system.
Alternatively, the rooted tuftstrings can be attached to sheets of
polymer with relatively "solid" surfaces such as sheets made of epoxy
3 5 resins, thermosets, thermoplastics, wood, and even metal. (Some of
these methods of attaching require the use of adhesives.) As described
2s
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
above with respect to a brush, an alternative to wrapping the elongated
pile sub-assemblies spirally, as shown in Fig. 15, is to make a pile surface
structure by creating an array in which one or more elongated pile sub-
assemblies are, for example, in parallel alignment to each other and
brought into contact with a bonding surface of a backing substrate.
Another method of securing more than one elongated pile
sub-assembly to a backing substrate is shown by the guide assemblies of
Figures 16 and 17. Unlike the rotating drum process described above,
these guide assemblies are capable of continuous operation and do not
1o have to be stopped to remove the "carpet" of elongated pile articles.
Figure 16 shows a schematic view of a guide for the elongated pile sub-
assembly 125 to create a pile fabric or article. This flat guide assembly 90
is better suited for relatively stiff substrates that would resist bending or
would otherwise take on a set from the curved guide 91 of Fig 17.
In Fig. 16, the long flat bottom surface is positioned with a
suitable gap between and parallel to (not shown) the substrate and the
guide assembly 90. The gap 310 is determined by one or more variables
which include the length of the short fiber segments 127, the vertical
dimension 315 of the beam, the depth of the beam guide groove 320 and
2o the depth of the adhesive. The beam dimension 315 must not be able to
pass through the spacing of 325. The gap 325 loosely confines the
portion of the long bundle segment proximal to the beam 119 together
with gap 328 which loosely confines the beam to correctly position the
short and long fibers normal to the substrate. Generally speaking the
spacing 325 is greater than 20% of the beam width 322 and more
preferably between 20% and 50% of the beam width. A typical set-up
would position the guide 90 with an elongated pile sub-assembly 125
threaded into the guide 90 over the flat substrate with a minimal gap
between the bottom surface of the beam and the substrate to substantially
3 o splay the short segment filaments 127 without causing binding of the
elongated pile sub-assembly 125 as it passes through the slot 97 of the
guide assembly 90.
The rooted tuftstring pile articles are continuously supplied
from one or more rooted tuftstring machines or from an inventory on
spools. The elongated pile sub-assemblies are directed by rolls and guide
pins (not shown) into the grooves of the guide with the short bundled end
29
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
extending outward therefrom. The guide mechanism guides a plurality of
individual short bundle segments of elongated pile sub-assemblies into
contact with the preferably continuously fed backing substrate. An
adhesive material such as a thermoset or thermoplastic adhesive is
applied to the surface of the substrate just prior to passing under the
guide assembly. Ideally, the linear rate of the process and the heat
capacity of the adhesive is adequate to achieve good wetting and
encapsulation of the short fiber segments prior to bonding with the
substrate. The adhesive is cooled as it passes under the guide assembly
Zo such that at the exit of the guide, the rooted tuftstrings are unable to
reposition themselves.
Another process embodiment of the present invention for the
flat guide of Fig. 16 uses a thermoplastic polymer melt delivery system
and die assembly to cast or to form the substrate on the exposed surface
s5 of the guide assembly 90 having exposed portions of elongated pile sub-
assemblies extending therefrom. In this case, the guide is inverted such
that the short fiber bundles extend vertically upward from the guide. A
polymer melt delivery system drops a curtain of polymer melt onto the top
guide surface. A band or strip of material such as KaptonT"" or TefIonT""
2 o may be used as a barrier to protect otherwise exposed metal surfaces
from the polymer melt when the polymer melt has a tendency to adhere to
the metal. The guide surface is sufficiently cool and causes a rapid
freezing of the polymer melt with the short segment fibers encapsulated
therein. The elongated pile articles assist in transporting the melt from
25 the plate and cooling of the thermoplastic polymer. Since the elongated
pile articles are sufficiently strong and not excessively heated, the sheet of
polymer will be adequately supported by the elongated pile articles after it
leaves the guide and continues to cool.
Another process embodiment of the present invention is
3 o shown schematically in Figure 17. The short segment fibers 127 of the
elongated pile sub-assembly 125 face toward the bonding element (e.g.
adhesive applicators 95) as the elongated pile sub-assembly are feed
through the guide 91. The short bundle segments of the elongated pile
sub-assembly preferably wipe the adhesive from the applicator end and
3 5 the elongated pile sub-assembly continuously wipes the guide surface to
avoid a large build up of adhesive in the guide as the elongated pile sub-
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
assembly is feed through the guide. The fabric backing 99 is fed in concert
with the tuftstring for bonding by one or more of the adhesive applicators
95 forming a pile covered fabric 199. Although two applicators are shown
in this embodiment, one may be sufficient. If one adhesive applicator 95 is
used the adhesive can be applied to the short bundle segments 127 just
prior to their contact with the substrate 99 or alternatively, directly to the
fabric backing or substrate 99. The number of applicators used may also
be increased to more than two in this embodiment if required.
This process embodiment is well suited for substrates that
to are flexible enough to conform to the curvature of a roll 91. The low
thermal conductivity of most substrates allow a hot melt adhesive to be
applied directly to the substrate with good heat retention and high flow
properties upon contact with the short bundle segments of the rooted
elongated pile article. For some substrates, some heating of the roll 93
may be required to maintain fluidity of the adhesive until time for the
desired bonding. This heating of the roll 93 may be needed particularly
when the substrates are extremely thin.
As with the guide assembly of Fig 16, the guide device of
Fig. 17 must be set up properly for optimum perFormance. The curvature
2 0 of the guide assembly 91 is designed to be concentric over the arc length
with the roll surface. Again the distance between the roll 93 rotating in the
direction of arrow 98 and the guide 91 is established to ensure the short
segment fibers splay and/or penetrate properly when pressed into the
substrate as shown in Figures 2A~4.
In both Fig. 16 and 17, the guide assembly can be mounted
onto a mechanism which permits adjustment of the guide vertically and if
desired, horizontally. This is advantageous since the guide can be
retracted for cleaning, thread-up or other preparatory/maintenance
activities. Small incremental adjustments in positioning can be
3 o accomplished while operating the process.
Figs. 18A and 18B show ultrasonic bonding of the rooted
tuftstring 125 to the substrate 115 in the present invention. The ultrasonic
horns 340, 345 vibrates in the direction shown by arrows 342, 343,
respectively, with anvils 350,355, respectively providing a rigid support for
the ultrasonic horns. A force 346, 347 presses the substrate 115 and the
short segment fibers into contact with each other while vibrational energy
31
CA 02464741 2004-04-26
WO 03/037134 PCT/US02/34102
is transmitted from the energized horn. The vibrational energy generates
frictional heating at the interface causing surface melting of at least one of
the short segment fibers 129, the beam 119, and the substrate 115,
creating a polymer flow zone that will bond the elongated pile sub-
s assembly to the substrate. Figs. 18A and 18B show the anvils 350,355
and the horns 340, 345, respectively, functioning as elongated pile sub-
assembly guides, respectively.
It is, therefore, apparent that there has been provided in
accordance with the present invention, an elongated pile sub-assembly
Zo, having "roots", guide device and products made from the elongated pile
sub-assemblies, that fully satisfies the aims and advantages hereinbefore
set forth. While this invention has been described in conjunction with a
specific embodiment thereof, it is evident that alternatives, modifications,
and variations will be apparent to those skilled in the art. Accordingly, it
is
z5 intended to embrace all such alternatives, modifications and variations
that fall within the,spirit and broad scope of the appended claims.
32
