U.S. patent application number 11/352551 was filed with the patent office on 2006-06-15 for nonwoven fabric and method and apparatus for manufacturing same.
Invention is credited to Wendell B. Colson, David Hartman, Paul Swiscz.
Application Number | 20060127635 11/352551 |
Document ID | / |
Family ID | 27494024 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060127635 |
Kind Code |
A1 |
Colson; Wendell B. ; et
al. |
June 15, 2006 |
Nonwoven fabric and method and apparatus for manufacturing same
Abstract
An apparatus for fabricating a unique nonwoven fabric which has
the appearance of a woven fabric includes a supply station for
parallel warp yarns, a support structure for orienting the parallel
warp yarns into a cylindrical orientation, a weft yarn applicator
for wrapping weft yarns around the cylindrically oriented warp
yarns after an adhesive scrim has been overlaid onto the warp
yarns, a heating station for activating the adhesive and a cooling
station for setting the adhesive, and a cutter for severing the
cylindrically formed fabric laminate so that it can be flattened
and wrapped onto a take-up roller. The weft yarn applicator
including a rotating drum wherein a plurality of spools of weft
yarn material are mounted in circumferentially spaced relationship
and a tensioner is provided for applying the weft yarn material
around the warp yarns in a predetermined tension which may be the
same as, greater than, or less than the tension in the warp
yarns.
Inventors: |
Colson; Wendell B.; (Weston,
MA) ; Swiscz; Paul; (Boulder, CO) ; Hartman;
David; (Framingham, MA) |
Correspondence
Address: |
Ernest V. Linek
Banner & Witcoff - 28th Floor
28 State Street
Boston
MA
02109
US
|
Family ID: |
27494024 |
Appl. No.: |
11/352551 |
Filed: |
February 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09869941 |
Jan 4, 2002 |
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PCT/US00/00571 |
Jan 10, 2000 |
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11352551 |
Feb 13, 2006 |
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10088614 |
Aug 6, 2002 |
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PCT/US00/25681 |
Sep 20, 2000 |
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11352551 |
Feb 13, 2006 |
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60115600 |
Jan 12, 1999 |
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60154717 |
Sep 20, 1999 |
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60155364 |
Sep 20, 1999 |
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60155365 |
Sep 20, 1999 |
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60155365 |
Sep 20, 1999 |
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Current U.S.
Class: |
428/105 ;
156/296; 428/107; 428/109; 428/112; 428/113; 442/366; 442/367;
442/368; 442/369; 442/50; 442/51; 442/52; 442/54; 442/58 |
Current CPC
Class: |
B29C 70/228 20130101;
B65H 81/00 20130101; D06H 7/08 20130101; Y10T 442/188 20150401;
B32B 7/12 20130101; B63H 9/0678 20200201; Y10T 442/198 20150401;
Y10T 442/646 20150401; D04H 3/07 20130101; Y10T 428/24091 20150115;
Y10T 442/191 20150401; Y10T 442/644 20150401; B32B 5/022 20130101;
Y10T 428/24124 20150115; D04H 3/04 20130101; D04H 3/12 20130101;
B29C 2793/009 20130101; Y10T 442/645 20150401; B32B 2305/20
20130101; B32B 2309/12 20130101; D02J 1/18 20130101; B29C 53/8016
20130101; Y10T 428/24116 20150115; Y10T 428/24074 20150115; Y10T
442/184 20150401; Y10T 442/186 20150401; B32B 5/26 20130101; B32B
41/00 20130101; Y10T 442/643 20150401; Y10T 428/24058 20150115 |
Class at
Publication: |
428/105 ;
442/050; 442/051; 442/052; 442/054; 442/058; 442/366; 442/367;
442/368; 442/369; 428/107; 428/109; 428/112; 428/113; 156/296 |
International
Class: |
B32B 5/12 20060101
B32B005/12; B32B 27/04 20060101 B32B027/04; D04H 3/05 20060101
D04H003/05 |
Claims
1. A non-woven fabric wherein the fabric consists essentially of
substantially parallel warp-direction yarns without any
weft-direction yarns, said warp-direction yarns being supported and
bonded on only one side by an adhesive coating, said adhesive
coating being non-continuous and having a thickness of from about
0.25 mil to about 1 mil.
2. A non-woven fabric wherein the fabric consists essentially of
substantially parallel warp-direction yarns without any
weft-direction yarns, said warp-direction yarns being supported and
bonded on only one side by an adhesive coating, said adhesive being
non-continuous and having been coated on one side of said fibers at
a level of from about 5 weight percent to about 25 weight percent,
based upon the weight of the fabric.
3. The non-woven fabric of claim 2, wherein the fabric weight is
about 50 g/m.sup.2 and the adhesive coating has weight of about 2
to 15 g/m.sup.2.
4. The non-woven fabric of claim 2, wherein the fabric weight is
about 50 g/m.sup.2 and the adhesive coating has weight of about 5
to 10 g/m.sup.2.
5. The non-woven fabric of claim 1 or 2, wherein the yarns are
selected from the group consisting of polymer fibers, natural
fibers, synthetic fibers, composite fibers, carbon fibers, glass
fibers and metallic fibers.
6. The non-woven fabric of claim 5, wherein the polymer fibers are
selected from the group consisting of polyester, polyethylene,
polypropylene, and nylon fibers.
7. The non-woven fabric of claim 5, wherein the natural fibers are
selected from the group consisting of cotton fibers, rayon fibers,
and wool fibers.
8. The non-woven fabric of claim 5, wherein the fibers are glass
fibers.
9. The non-woven fabric of claim 5, wherein the fibers are metal
fibers, selected from the group consisting of copper, gold,
aluminum, silver, and platinum.
10. The non-woven fabric of claim 1 or 2, wherein the adhesive
coating is applied to the yarns by dip/nip saturation, spraying,
gravure coating, or kiss coating.
11. A method of forming a non-woven fibrous web, said method
comprising the steps of: a. forming a substantially parallel array
of yarns consisting essentially of substantially parallel
warp-direction yarns without any weft-direction yarns, said array
of yarns having two sides, a top side and a bottom side; b.
contacting only one side of said parallel array of yarns with a
thin coating of wet or molten adhesive; and c. drying the wet or
molten adhesive coating to form a cohesive web of non-woven
parallel yarns.
12. A non-woven fibrous web made according to the method of claim
11.
13. The method of claim 11, wherein the adhesive coating is applied
to the fibrous web by dip/nip saturation, spraying, gravure
coating, or kiss coating.
14. The method of claim 11, wherein the yarns are selected from the
group consisting of polymer fibers, natural fibers, synthetic
fibers, composite fibers, carbon fibers, glass fibers and metallic
fibers.
15. The method of claim 14, wherein the polymer fibers are selected
from the group consisting of polyester, polyethylene,
polypropylene, and nylon fibers.
16. The method of claim 14, wherein the natural fibers are selected
from the group consisting of cotton fibers, rayon fibers, and wool
fibers.
17. The method of claim 14, wherein the fibers are glass
fibers.
18. The method of claim 14, wherein the fibers are metal fibers,
selected from the group consisting of copper, gold, aluminum,
silver, and platinum.
19. The non-woven fabric of claim 2, wherein the substantially
parallel yarns are uniformly spaced.
20. The non-woven fabric of claim 11, wherein the substantially
parallel array of yarns are uniformly spaced.
21. A non-woven fabric comprising substantially parallel yarns held
together by bridges of an adhesive which is substantially only on
one side of the yarns and is discontinuous but prevents twisting of
the individual yarns.
22. The non-woven fabric of claim 21 which consists essentially of
substantially parallel warp-direction yarns that are supported and
bonded on the one side by the adhesive and wherein the adhesive is
on the one side of the yarns at a level of from about 5 weight
percent to about 25 weight percent, based upon the weight of the
fabric.
23. The non-woven fabric of claim 22 wherein the fabric weight is
about 50 g/m.sup.2 and the adhesive weight is about 2 to 15
g/m.sup.2.
24. The non-woven fabric of claim 23 wherein the fabric weight is
about 50 g/m.sup.2 and the adhesive weight is about 5 to 10
g/m.sup.2.
25. The non-woven fabric of any one of claims 21-24 wherein the
yarns are selected from the group consisting of polymer fibers,
natural fibers, synthetic fibers, composite fibers, carbon fibers,
glass fibers, metallic fibers and graphite.
26. The non-woven fabric of claim 25 wherein the yarns are polymer
fibers selected from the group consisting of polyester,
polyethylene, polypropylene and nylon fibers.
27. The non-woven fabric of claim 25 wherein the yarns are natural
fibers selected from the group consisting of cotton fibers, rayon
fibers and wool fibers.
28. The non-woven fabric of claim 25 wherein the yarns are metal
fibers selected from the group consisting of copper, gold,
aluminum, silver and platinum.
29. The non-woven fabric of claim 25 wherein the yarns are glass
fibers.
30. The non-woven fabric of any one of claims 21-24 wherein the
adhesive has been applied to the first yarns by dip/nip saturation,
spraying, gravure coating or kiss coating.
31. The non-woven fabric of any one of claims 21-24 wherein the
adhesive has a thickness of from about 0.25 mil to about 1 mil.
32. The non-woven fabric of any one of claims 21-24 wherein the
adhesive is a heat activatable adhesive.
33. The non-woven fabric of claim 32 wherein the adhesive is a hot
melt adhesive.
34. The non-woven fabric of claim 33 wherein the adhesive is a hot
melt copolyester polymer.
35. The non-woven fabric of claim 32 wherein the adhesive is a
scrim or lace web of adhesive or a meltblown adhesive.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional filing from copending
application Ser. No. 09/869,941, filed Jan. 4, 2002. The '941
application was a 371(c) National Phase filing of PCT Application
No. PCT/US00/00571, filed Jan. 10, 2000, which designated the
United States and was published in the English language on Jul. 20,
2000 as PCT Publication No. WO 00/41523. The PCT Application
claimed priority from the following U.S. Provisional patent
applications--Serial No. 60/115,600, filed Jan. 12, 1999; Serial
No. 60/154,717, filed Sep. 20, 1999; Serial No. 60/155,364, filed
Sep. 20, 1999; and Serial No. 60/155,365, filed Sep. 20, 1999. The
disclosures of these applications are hereby incorporated herein by
reference.
[0002] This application is also a continuation filing from
copending application Ser. No. 10/088,614, filed Jun. 8, 2002. The
'614 application was a 371(c) National Phase filing of PCT
Application No. PCT/US00/25681, filed Sep. 20, 2000, which
designated the United States and was published in the English
language on Mar. 29, 2001 as PCT Publication No. WO 01/21877. The
PCT Application claimed priority from U.S. Provisional Application
Serial No. 60/155,365, filed Sep. 20, 1999. The disclosures of
these applications are hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0003] This invention relates generally to nonwoven fabric
materials, to processes for the preparation of such materials, and
to various apparatus used in the manufacture of such materials.
BACKGROUND OF THE INVENTION
[0004] As described above, the present invention relates to
nonwoven fabric materials and, more particularly, to a nonwoven
fabric material which may have the appearance of a woven fabric and
which is easily engineered along with an apparatus and method for
manufacturing same by pulling warp yarns gently bound by an
adhesive material along the longitudinal extent of the surface of a
cylindrical support and subsequently helically wrapping weft yarns
transversely around the cylindrically supported warp yarns prior to
activating the adhesive, and setting the adhesive to bond the
completed product.
[0005] Nonwoven fabrics are similar to woven and knitted fabrics in
that all are planar, inherently flexible, typically porous
structures composed primarily of natural or synthetic fiber
materials (i.e., yarns, threads, or filaments). Nonwoven fabrics
are unique in that they can be engineered to resemble woven or
knitted fabrics, but they can also be made to have superior
physical characteristics over woven or knitted fabrics. Thus,
nonwoven fabrics are highly influenced by the properties of their
constituent fibers and the manner in which the nonwoven fabric is
prepared. Typical methods for preparing nonwoven fabrics include
mechanical, chemical and thermal interlocking of layers or networks
of the fiber materials.
SUMMARY OF THE INVENTION
[0006] The present invention comprises a nonwoven fabric-like
material. The "fabric-like" material preferably has the general
appearance of a fabric, most preferably of a woven fabric, and has
one or more characteristics of a traditional cloth fabric,
including uniformity of texture, pliability, strength, appearance,
and the like. One preferred embodiment of the fabric-like material
comprises substantially parallel yarn fibers (or fiber-substitutes)
held together in a nontwisting manner by a series of adhesive
bridges or a combination of adhesive and stray yarn fiber bridges
on one side of the parallel fibers. This fabric-like material can
be used as is, or it can be further transformed into other
fabric-like materials by further processing as described herein.
The present invention also provides a continuous, in-line method
and apparatus for manufacturing such nonwoven fabrics in such a
manner that the nonwoven fabric can have a variety of desirable
physical characteristics. The method and apparatus are further
designed such that the nonwoven fabric can be produced at a
relatively rapid rate in comparison to known systems for
manufacturing wovens.
[0007] Reference to the term "yarn" will be made throughout the
present specification and the term should be broadly interpreted to
include mono and multi-filament yarns and/or strands of various
materials. The yarns may be large or small in diameter or denier,
and can be made from many types of materials including, but not
limited to, polyester, polyethylene, polypropylene and other
polymers or plastics; wool, cotton, hemp and other natural fibers;
blends of natural and/or synthetic fibers; as well as
fiber-substitutes such as glass, metal, graphite and the like. It
is conceivable that some of the warp and/or weft yarns may be metal
and/or metal alloys such as, for example, copper and/or aluminum
wire, or combinations of metal and synthetic or natural fibers. It
should also be appreciated with the description that follows that
various densities of warp or weft yarn wrap will be referenced and
these densities will vary depending upon the type of yarn as
described above and the desired characteristics of the nonwoven
product being manufactured.
[0008] For the purposes of this disclosure, "warp" yarn materials
include any combinations of materials or combinations of yarns that
have the yarns or fiber-substitute materials primarily positioned
to run in the machine direction of the apparatus and that are
aligned in a controlled manner before being treated with an
adhesive material to form a fabric-like, nonwoven substrate. "Weft"
yarn materials include any combinations of materials or
combinations of yarns that have the yarns or fiber-substitute
materials primarily positioned to run substantially perpendicular
to the warp yarn materials.
[0009] One especially preferred nonwoven fabric of the present
invention has the appearance of a woven fabric, but is considered a
nonwoven because the warp and weft yarns are not interlaced or
interwoven, but instead are laid one over the other and adhered
together. There are several embodiments of this product of this
invention. The first embodiment involves the laydown of weft yarns
onto a substrate comprised of a conventional nonwoven including,
but not limited to, a bonded carded web, a wet laid, an air laid,
or a spunbonded web.
[0010] In one preferred nonwoven embodiment, a bonded carded web is
used as the substrate for the weft yarns. This web material is
particularly suited for the nonwoven of the present invention
because the carding process, by its nature, typically orients
fibers in the machine direction of the web. A fiber orientation in
which the majority portion of the fibers run in the machine
directions creates a substrate in which the fibers mimic warp yarns
and are substantially perpendicular to the orientation of the weft
yarns. When viewed with a light shining through a product in
accordance with the present invention, the perpendicular
orientation of the carded fibers in the web relative to the weft
yarns, creates the visual impression of a woven material.
[0011] The bonded carded web can be printed with an adhesive or, in
accordance with one embodiment of the present invention, a randomly
oriented adhesive lace or scrim can be lightly bound to its surface
prior to application of the weft yarns. This type of adhesive lace
allows for the use of a low level of adhesive by weight in a
loosely applied laydown such that there are portions of the weft
yarns that are not adhesively connected to the warp nonwoven
substrate. The structure, because of the discontinuous adhesive
laydown, also has a certain degree of porosity which mimics the
breathability of a woven which has a yarn-on-yarn construction and
no film. The resultant structure has improved hand that mimics that
of a woven material. The adhesive is preferably made from
thermoplastic polymer, but other adhesives may be used including
thermoset adhesives, and 100% solid adhesives. The preferred type
of adhesive is preferably a thermally activated copolyester that on
a weight basis represents about 10-20% of the weight of the
complete nonwoven structure. This adhesive scrim is sandwiched
between the nonwoven substrate described above, and the weft yarns.
Once activated, the adhesive holds the weft yarns to the nonwoven
substrate.
[0012] In yet another embodiment, a plurality of warp yarns are
formed into an aligned group, substantially parallel and equally
spaced apart. If desired, different warp yarns, for example yarns
of various types (synthetic, natural, yarn substitutes) and/or
yarns of various deniers, can be aligned using this apparatus,
resulting in nonwoven fabric materials having particularly
interesting and unique properties. This parallel grouping of yarns
is advantageously fixed in place by forming an adhesive coating,
printed on only one side of the warp yarns, using a hot melt roll
coater. Cooling of the hot melt adhesive occurs almost
instantaneously, and the resulting product is a fixed web or
substrate consisting essentially of a plurality of aligned warp
yarns and an adhesive film positioned substantially only on one
side of said yarn fibers.
[0013] An especially preferred embodiment of the warp yarn material
generator used herein comprises a warp yarn aligner, through which
a plurality of individual yarns or threads (alike or different) are
passed to be placed in substantially parallel alignment. Once
aligned, the yarns are next passed to the adhesive station, which
is preferably a hot melt roll (e.g., gravure) coater. In this
device, a thin film of hot melt adhesive is imprinted on only one
side of the plurality of aligned warp yarns. The adhesive does not
remain as a film after application; the adhesive typically
partially separates when applied to the parallel yarns. Bridges of
adhesive and/or fragments of yarn strands (each independently with
or without an adhesive coating) form and/or otherwise extend over
the spaces between parallel yarns. These bridges hold the yarns
together and prevent individual yarns or threads from twisting
relative to one another.
[0014] As used herein, the term "bridges" is meant to define the
physical result of applying a thin film of adhesive to one side of
aligned warp yarns; namely a combination of adhesive strands,
adhesive coated fragments of yarn strands, and/or fragments of yarn
stands which contact adhesive on two or more aligned yarns (e.g.,
at two or more points), such that the series of aligned warp yarns
are held together in a substantially user selected spatial
arrangement, and wherein the yarns do not twist, rotate, or
otherwise separate relative to one another due to the presence of
the bridges on one side. In other words, the bridges lock the yarns
in place in a manner selected by the manufacturer of the warp yarn
material. Upon cooling of the adhesive, a flexible, yet unified
substrate web of warp yarns having the look and feel of a nonwoven
fabric, is obtained. This warp yarn substrate is suitable for
further processing as a nonwoven fabric or otherwise. If desired,
this combination of the warp yarns and adhesive may be wound onto a
spool for later handling, or formed into sheets for other uses as
desired.
[0015] The preferred warp yarn aligner has a plurality of
vertically displaced sets of horizontally spaced rollers. The upper
set of rollers is within a horizontal plane positioned above a
horizontal plane containing the lower set of rollers, though it is
conceivable that the orientation of the sets of rollers are not an
upper and lower set of rollers but possibly a left and right set of
rollers or somewhere in between so that the plane of the sets of
rollers would be horizontally rather than vertically displaced or
somewhere in between. The rollers are aligned transversely with
each other. In the arrangement where the rollers are positioned
within horizontal planes, each roller in a set is horizontally
offset from rollers in the other set so that rollers in each set
are positioned between rollers of the other set and the outer
perimeter of the rollers in one set overlaps the outer perimeter of
the rollers in the other set. In this manner the warp yarns which
pass transversely through the sets of rollers must pass under the
upper set of rollers and over the lower set of rollers contacting
all of the rollers in each set with an engagement arc on each
roller. It has been found that an engagement arc of about 20
degrees is preferable herein, although higher or lower degrees
should also be useful. At least some of the rollers may be
roughened on their outer surface to impart a vibration to the
yarns, preferably in the plane of the web.
[0016] The warp yarns, e.g., from a beam of the same, are roughly
aligned when delivered to the rollers, e.g., through a comb device
or otherwise, are passed through the spaces between the sets of
rollers as described above. The rollers are driven at a roller-face
speed that is faster than the linear speed of the yarns. By over
driving the rollers relative to the linear speed of the yarns it
has been discovered that the yarns will become substantially
parallel. The textured rollers could be run at a speed slower than
the yarns and achieve the same effect, but over speeding the
rollers at a ratio within the range of 2:1 to 3:1 has been found to
be very effective. Parallel alignment of the warp yarns is
important for most nonwoven products because it results in a
uniform appearance of the yarns which makes the end product look
more like a woven product.
[0017] One preferred hot melt adhesive applicator is a Rotothermt
hot melt roll coater. In operation of the hot melt adhesive coating
apparatus the series of parallel warp yarns are drawn through the
glue apparatus, supported by a series of rollers. A thin film web
(ranging from about 0.25 to 1 mil) of hot melt adhesive is
continuously gravure coated onto one side of the aligned warp
yarns. The actual thickness of the film web varies within the range
specified, and depends upon the weight of the fabric, and is
usually applied at from about 5% to 25% of the fabric weight. For a
fabric weight of 50 g/m.sup.2 the adhesive may be applied at from
about 2 to 15 g/m.sup.2, preferably at from about 5 to 110
g/m.sup.2. After being gravure coated, the warp yarn substrate
rapidly solidifies, fixing the parallel arrangement and equal
spacing of the yarns. The adhesive film web also prevents twisting
or rolling of the yarns, which maintains the "feel" of the product.
A cooling path is provided to ensure that the adhesive web is set
before the substrate is collected, e.g., in a roll form, sheet
form, or otherwise as desired by the manufacturer or end user.
[0018] The yarn orientation produced in this embodiment, in which
the fibers run in the machine direction, provides a nonwoven fabric
material substrate in which the fibers mimic warp yarns, which can
be used in subsequent nonwoven manufacturing processes to make
materials that have the visual impression and physical feel of a
woven material. Such materials often exceed the physical
characteristics of woven fabrics, particularly with respect to
strength, resistance to tearing, fraying, and the like, without the
necessity of post treatments, including chemical treatments, to
achieve these properties. Post treatments, if desired, could still
be employed, particularly if beneficial properties were achieved
thereby.
[0019] While the above described adhesive methods are preferred
embodiments, other methods of preserving the aligned warp yarn
strands could be employed. For example, the warp yarns can be
contacted with a dry adhesive layer that is heated and then cooled
to bond the materials; the adhesive could be applied with a melt
blown applicator; or the aligned warp yarn strands could be bound
via an adhesive to another layer of material, a film of adhesive,
or a substrate comprising adhesive and another nonwoven fabric
material.
[0020] Another embodiment of the nonwoven fabric of the present
invention involves the combination of warp yarns and weft yarns,
with the weft yarns being positioned substantially perpendicular to
the warp yarns. The terms "substantially perpendicular" are used to
define an approximately 90 degree relationship of the
cross-directional intersection of the weft and warp yarns to one
another. This may vary by up to about 5 degrees in either direction
away from a perfect 90 degree intersection, e.g., from about 85
degrees to about 95 degrees. One such product produced in
accordance with the present invention has an intersection angle of
about 89.7 degrees.
[0021] In one embodiment of the cross-directional (or "XD")
apparatus, the warp and weft yarns are adhered to one another with
the same adhesive material that is used to bond the warp yarns as a
substrate. The yarn density can approach as high as 140 yarns per
inch for a single strand 36 cotton count yarn. This is
substantially higher than the density available in the same yarn
count of a conventional woven fabric which has a maximum yarn
density of about 90 yarns per inch for the same yarn.
[0022] The use of an open structure adhesive material (e.g., scrim,
lace or the like) in the preferred embodiments of the XD apparatus
allows the formation of a finished fabric structure with very good
hand properties. This is due to the ability of both the warp and
the weft yarns to move freely in the positions where they are not
joined by the adhesive lace. The adhesive preferably represents
less than 5-20% by weight of the entire structure.
[0023] In yet another embodiment of XD apparatus, the warp and weft
yarns are again positioned substantially perpendicularly to one
another as described above, but instead of being joined by an
adhesive scrim or lace, they are joined by a melt blown adhesive
web. The meltblown process is well known in the art and creates
micro denier yarns. These yarns can be laid down more uniformly
than the adhesive scrim, but yet use less adhesive in the
structure. The micro denier yarns if activated properly will create
a finished structure that has good hand, but a more uniform
appearance than the finished structure provided with an adhesive
scrim.
[0024] A preferred XD apparatus used herein for joining the warp
yarn materials and the weft yarn materials includes the following
components:
[0025] (a) a supply station for aligned warp yarn materials and the
adhesive material, whether as a film, scrim or lace; or a meltblown
web or other bondable material added to the supply station,
[0026] (b) a warp yarn material delivery station where the warp
yarn material is conformed longitudinally to the outer surface of a
cylindrical support so as to extend longitudinally of the
support,
[0027] (c) a weft yarn application station through which the warp
material passes,
[0028] (d) a heating or adhesive activating station,
[0029] (e) a cooling or adhesive setting station, and
[0030] (f) a fabric take-up station; e.g., a take-up roll, a
sheeter, or the like.
[0031] In the operation of one version of the XD apparatus, the
transfer roll of warp yarn material that is produced on the warp
yarn material manufacturing unit is transferred to the supply
station and the warp yarn material is extended through the
apparatus on a transfer belt from the supply station to a take-up
station. As the warp yarn material extends through the apparatus it
is supported along the length of a substantially cylindrical, or as
an alternative a polygonal cross-sectioned, support surface on the
transfer belt and the warp yarns or fibers maintain their parallel
relationship along the length of the cylindrical surface. The warp
yarn material is thereby disposed in a substantially cylindrical
configuration. A drive roll is positioned between a take-up roll at
the take-up station and a cooling or adhesive setting station that
is upstream from the take-up station. The drive roll rotates the
transfer belt along the length of the support surface thereby
advancing the warp yarn material through the apparatus at little or
no tension and at a predetermined and variable speed.
Alternatively, the take-up roll can be replaced with other
conventional processing equipment, including for example, a
sheeter, a laminator, or the like.
[0032] Prior to encountering the adhesive activating and setting
stations, the warp yarn material passes through the weft yarn
application station where a plurality of continuous weft yarns are
wrapped around the warp yarn material with the adhesive material
disposed between the warp yarn material and the weft yarns. It will
be appreciated that as the warp yarn material passes through the
weft yarn application station it is still in a substantially
cylindrical configuration. The cylindrical composite structure of
warp yarn material, adhesive and weft yarns is passed through the
activating or heating station where the adhesive is activated to
bond the warp yarn material and weft yarns together. Immediately
thereafter, the composite structure passes through the setting or
cooling station where the adhesive is set so that the warp yarn
material and weft yarns are adhesively bonded together into a
substantially fixed nonwoven relationship which has the appearance
of a woven product. It will be appreciated by those skilled in the
art that other systems for activating and deactivating the adhesive
can be used, such as by way of example, moisture, high frequency
light, pressure or other temperature regulating systems. A cutter
longitudinally cuts the composite structure and as the material
continues through the apparatus, the material is forced into a
planar configuration as the support surface is progressively
converted from a cylindrical configuration to a flat
configuration.
[0033] In one embodiment of the weft yarn application station, an
enclosed rotating drum is provided that has a ring-like enclosure
with a plurality of supplies of weft yarn materials on separate
individual spools, cones or the like. The drum has a cylindrical
axial passage along its longitudinal axis through which the warp
yarns with the overlying adhesive pass. Each spool of weft yarn
material is associated with a tensioner also mounted on the
rotating drum that is spaced slightly from the cylindrical axial
passage so as to be in closely spaced relationship with the warp
yarn material and adhesive. The weft yarn material passes through
the tensioner and subsequently around a guide pin that is also
mounted on the drum but immediately adjacent to the warp yarn
material and adhesive overlay. The weft yarn material, after
passing through the tensioner, extends around the guide pin and
immediately onto the adhesive and is caused to be laid transversely
around the adhesive and warp yarns as the drum rotates about its
axis. The tensioner is adjustable so that the tension in the weft
yarn, as it is wrapped around the warp yarn material, can be
adjusted so as to have a tension the same as, greater than or less
than whatever tension there may be in the warp yarns.
[0034] In the tensioner embodiment described above, up to twelve
spools of weft yarn material can be mounted within the rotating
drum on a radial wall thereof even though the size of the drum can
be increased or the density of the spools within the drum can be
increased so as to allow for more or less than twelve spools. By
providing twelve spools of material at a pre-determined equal
circumferential spacing within the drum, the drum can be properly
balanced so that it can be rotated at high rates of speed
substantially without vibration.
[0035] In the tensioner embodiment, it is also important that the
twelve spools, or however many are used, are at an exactly equal
angular displacement relative to each other. Exact angular
displacement and the pushing of the weft yarns against the next
adjacent weft yarn results in the weft yarns being precisely and
controllably placed so as to optimize weft yarn packing. If an
alternative spacing is desired however, then the exact equal
angular displacement is not necessary. In such cases the fiber
spacing will be controlled by a predetermined angular spacing of
the rolls.
[0036] The drum also has a separate power source for rotating the
drum at a different speed than the power source at the take-up
station in the apparatus which advances the transfer belt and the
warp yarn material through the apparatus. Accordingly, the warp
yarn material can be moved linearly through the apparatus along the
cylindrical support at either a selected steady speed and/or at a
variable speed, while the rate of rotation of the drum can be at an
independent selected steady speed and/or at a variable speed. This
allows the weft yarns to be wrapped around the warp yarn material
at predetermined constant and/or desired variable spacings and also
at an angle relative to the longitudinal axis of the warp yarn
material. In other words, while the weft yarn material is wrapped
substantially perpendicularly to the warp yarn material, in reality
it is slightly offset from perpendicular and the angle of offset
can be varied by varying the rate of rotation of the drum relative
to the linear speed at which the warp yarn material is advanced
through the drum. For example, if the user wished to vary the
average spacing of the weft yarns, the belt speed would be adjusted
relative to the speed of the drum (one faster, one slower). Varying
the degree of difference in relative speeds changes the weft yarn
to warp yarn spacing and incidentally changes the angle of laydown
of the weft yarns.
[0037] In an especially preferred embodiment of the XD apparatus,
several components previously identified have been modified and/or
omitted, as discussed in detail below. The warp yarn material
continues to be supported on a transfer belt and configured into a
cylindrical form. A drive roll continues to drive the cylindrical
warp yarn material through the weft yarn application station, where
the cylinder of warp yarns are supported to allow application of
the weft yarns. Heating and cooling stations are used to set the
adhesive between the warp and weft layers, and the cylindrical form
is cut and flattened under tension to form a unified structure
having the appearance of a woven fabric.
[0038] In this embodiment, the weft yarn application station
comprises an enclosed rotating drum that has a ring-like enclosure
with a plurality of supplies of weft yarn material on separate
individual spools, cones or the like. The drum has a cylindrical
axial passage along its longitudinal axis through which the warp
yarns with the overlying adhesive pass. The cylindrical axial
passage is fitted with a conical aligner, which serves as the final
guide for guiding the rotating weft yarns into position on the warp
yarns in substantially perpendicular alignment. The conical aligner
is a stationary unit, which has an angled or sloped surface
directed toward the forward movement of the warp yarns. A preferred
slope ranging from about 15 to 60 degrees has been found to be
effective, with a 45 degree slope being most preferred.
[0039] Each of the weft yarns are delivered to a fixed point on the
stationary conical aligner, and from that point each yarn falls
down the slope of the aligner and finally falls into place on the
cylindrical warp fabric yarns, landing on the adhesive on the
exposed surface of the warp yarns. By use of the conical aligner
described herein, the weft yarns do not overlap one another.
Instead, the weft yarns slide down the aligner and onto the warp
fabric. In tight packing cases, the tension imparted to the weft
yarns causes individual yarns to hit one another, whereas in loose
packing cases, the individual yarns do not usually strike one
another on the conical aligner. The individual fibers are laid
transversely around the warp yarn substrate where they contact the
adhesive on the one side of the warp yarn substrate as the drum
rotates. As described above, the speed of rotation may vary as
desired, from very slow (e.g., 200 rpm or less) to very fast (e.g.,
over 1000 rpm). A speed of about 500-600 rpm has been found to be
very useful in forming the preferred nonwoven fabrics. Tension of
the weft yarns is automatically provided by the centrifugal
rotation of the drum.
[0040] It will be appreciated that both the tensioning of the weft
yarns and the conical aligner's guiding of the placement of the
weft yarns at the surface of the warp yarn material, in conjunction
with the rotation of the weft yarns around the warp yarn material
results in very high accuracy of weft yarn placement. High accuracy
of the yarn placement can result in high weft yarn packing density,
uniformity of the weft yarn, structural engineering of the fabric
based on known placement of the weft yarns, and overall improved
performance of the product.
[0041] As in the tensioner embodiment described above, a number of
spools (e.g., 8,10,12,14,16,18, etc.) of weft yarn material can be
mounted within the rotating drum on a radial wall thereof even
though the size of the drum can be increased or the density of the
spools within the drum can be increased so as to allow for more or
less than twelve spools. An even number of spools has been found
easy to space evenly within the drum. However, an odd number of
spools could likewise be employed, if spaced properly in the drum
to maintain a balanced state.
[0042] It will be appreciated that while the nonwoven product may
be heat set and given a finished high strength bond lamination
while still in the cylindrical configuration on the substantially
cylindrical support surface as described above, an alternative heat
set and lamination method may be used.
[0043] In one preferred alternative method, post lamination
treatment of the bonded warp and weft yarns may be desirable. A
lamination apparatus may be used, either as a separate unit, or as
an integral part of the XD apparatus, positioned, e.g., between the
drive roll and the take up roll. A laminator in this section is
preferably a flat belt laminator. The nonwoven material is fed
through the post laminating section under a predetermined tension
and is re-heated, and re-cooled, before being wound up onto the
take up roll. The use of the flat belt laminator may reduce curl
and/or shrinkage in the cross-direction of the product and produce
a better bond.
[0044] One especially preferred laminator apparatus comprises a
separate unit with a dual belt driven, continuous pressure
lamination section that utilizes pressure, heat and cooling to bond
at least two substrates (plies) with adhesive between the layers of
the substrates.
[0045] Such a separate laminator apparatus can be employed to make
a variety of composite and/or reinforced materials. One or more of
the component parts of the laminate (i.e., the substrates or plies)
may be a woven fabric material, a nonwoven fabric web, or a mat of
fibers. Adhesive materials, preferably thermoplastic materials, are
used to bond the various substrates in the laminate construct.
These materials may be melted and remelted over and over. When used
to laminate yarns, especially polymer yarns, thermoplastic
copolyester adhesives are preferred, as these materials may be
selected to have a melting temperature below the melting
temperature of the yarns. Industrial type laminates that may be
formed using the laminator described herein include natural and/or
synthetic fabric-based, asbestos-based, glass-based, nylon-based,
flame-retardant and/or flame-resistant based, and mixtures thereof.
Laminates of other materials may also be prepared as will be
appreciated by those having ordinary skill in the field.
[0046] Nonwoven fabrics such as those formed on either of the XD
apparatus described above are one especially preferred class of
materials used as the plies or substrates in the pressure laminator
described herein. Preferably, both substrates are nonwoven fabric
substrates, one of the fabric substrates representing the weft
strands and another representing the warp strands. The adhesive
used to bond the nonwoven substrates should be activated by heat
during the lamination process. The combination of pressure, heating
to activate the adhesive and cooling of the joined substrates while
still under pressure, minimizes shrinkage, sets the yarn size in
the final nonwoven fabric laminate, and imparts high strength,
including fray resistance characteristics, to the final product. In
addition, because the laminate is being formed under pressure, the
warp and weft yarns are forced into intimate contact, whereby the
adhesive between the layers is spread there between, giving the
final laminate the appearance of a woven product. The adhesive is
captured between the warp and the weft yarns, preferably in an
invisible manner.
[0047] The most preferred lamination apparatus used for pressure
bonding nonwoven substrates has an outer housing or frame in which
a rectangular pressure box is mounted. The shape of the box need
not be rectangular, but this shape is currently preferred. The
pressure box comprises two spaced apart sections, an upper section
and a lower section, each of which has pressure seals along its
four edges, and each of which is further provided with a plurality
of both heating and cooling elements. Two counter rotating drive
belts, an upper drive belt and a lower drive belt, contact one
another at and together run through a space between the two
sections of the pressure box. The belts are dimensionally larger
(length and width) than the seals of the pressure box. This is
necessary to permit pressurization of the box, both above and below
the two belts. One belt is driven in a clockwise manner and the
other belt is driven in a counterclockwise manner. Once the belts
are in motion, one end of the pressure box is the inlet (feed) end
and one end is the outlet end of the laminator.
[0048] The lower section of the preferred pressure box is mounted
rigidly to the frame or housing, whereas the upper section of the
pressure box can be adjusted as necessary to permit access to the
interior of the box. Normally, the sections are spaced apart
sufficiently to permit passage of the drive belts there through
under pressure (or in a depressurized state), with or without
material to be laminated there between. If desired, these positions
could be reverse, with the lower section e.g., spring mounted
against a fixed position upper section.
[0049] During the lamination process, substrate materials to be
laminated are passed through a pressure seal at the inlet end of
the pressure box, and into the space between the two drive belts.
Air pressure applied to the upper and lower sections of the
pressure box is used to compress the air-impermeable belts toward
one another, creating a diaphragm effect between the belts, thereby
compressing the substrates situated there between. Movement of the
two belts through the pressure box allows for the continuous
feeding of substrate materials and thermoplastic adhesive. Once
therein, the substrates are nipped or pressed together by the
diaphragm effect caused by the pressure applied to the belts. The
pressed substrates are then heated under pressure, melting and
spreading the adhesive. This allows the substrate layers to come
close together, preferably with at least some portions of the warp
and weft yarn strands becoming coplanar or nearly coplanar. The
heated substrates are then cooled, while still under pressure,
forming the final laminate. The cooled laminate exits the pressure
box through an exit pressure seal, where it is collected as
desired. When two or more nonwoven polyester substrates (e.g., at
least one warp substrate and at least one weft substrate) are
laminated in this apparatus, the thickness of the laminate at the
outlet end of the laminator is at least 5%, preferably at least 10%
and most preferably at least about 20% less than the combined
thickness of the substrates and adhesive, as measured at the inlet
end of the laminator.
[0050] The upper and lower sections of the pressure box are
equipped with a plurality of heating and cooling elements, which
are used to activate and set the thermoplastic adhesive between the
substrate layers. Heating and cooling can be accomplished by any
means available to the skilled artisan. For example, hot pellets,
contact heating bars, radiant heating bars, hot fluids (e.g., oil),
hot gases (steam), and the like can be employed. Likewise, cooling
fluids (e.g., water), adiabatic cooling methods, cold gases, and
the like can be employed. If desired, two separate pressure fluids
can be employed, one serving as the heating medium, the other
serving as the cooling medium. The skilled artisan can readily
devise equivalent pressurization and heating and/or cooling systems
given this disclosure.
[0051] In an especially preferred embodiment, the plurality of
heating and cooling bars located in the lower section of the
pressure box are rigidly mounted, whereas the plurality of heating
and cooling bars in the upper section of the pressure box are
mounted so as to float on top of the materials being laminated.
This arrangement has been found to be especially useful in the
preparation of nonwoven fabrics. Shrinkage is minimized or
eliminated and the final laminate has the physical characteristics
(feel and appearance) of a thermomechanically finished fabric.
[0052] Advantageously, at least about 10%, preferably at least
about 25% and most preferably about 50% of the box interior at the
inlet end of the pressure box is provided with heat bars, and the
remainder of the pressure box, again, at least about 10%,
preferably at least about 25% and most preferably about 50% of the
box interior, is provided with cooling bars. The heating bars are
ideally located at the inlet end of the pressure box and the
cooling bars are ideally located at the outlet end of the pressure
box. If desired, multiple zones of heating and cooling could be
included within the pressure box; e.g., heat/cool, heat/cool,
heat/cool, etc. Alternatively, the sequence can include a preheat
section, a full heating and hold, followed by a cooling sequence.
The only requirements for successful lamination are the heat
activation of the adhesive and the cool setting of the adhesive,
both occurring under pressure.
[0053] The current rectangular pressure has a pressure area about
1500 square inches(in.sup.2). The drive belts, which are
substantially non-porous Teflon.RTM. coated belts, are pressurized
from both sides of the pressure box with air (or other fluid
medium) pressure of at least 2 psi, preferably at least about 5
psi, and most preferably at least about 10 psi. Higher pressures
can be achieved with modification of the equipment to support and
sustain the same. This pressure applied to the belts is equivalent
to a compressive weight (force) ranging from about 3000 lbs to
about 15,000 lbs, applied over the 1500 in.sup.2 area of the
current pressure box. For laminating the nonwoven fabrics of the
present invention, a compressive force from about 5,000 lbs to
about 15,000 lbs is typical, and a compressive force of about
15,000 lbs (at 10 psi gauge) has been found to be especially
preferred to date. This is important because in a traditional
pressure laminator, which uses top and bottom platens, if a weight
of 15,000 lbs was placed on the top platen to provide the
compressive force to effect lamination, any belt running thereunder
would either stop and/or break, due to the excessive amount of
friction that would be generated. Low pressure continuous
laminators of this type (continuous, 2 belt, heat/cool zones) are
commercially available. Such laminators provide a maximum of about
2 psi compressive force. This upper limit is generally dictated by
belt stoppage and/or breakage.
[0054] Other and further embodiments of the present invention will
be apparent from the following detailed description and claims, and
are illustrated in the accompanying drawings which, by way of
illustration, show preferred embodiments of the present invention
and the principles thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] FIG. 1 is a fragmentary diagrammatic isometric view of the
apparatus of the present invention.
[0056] FIG. 1B is a diagrammatic vertical section taken through a
flat bed laminator that can form part of the apparatus shown in
FIG. 1.
[0057] FIG. 2 is a fragmentary diagrammatic top elevation of the
apparatus shown in FIG. 1 with the adhesive scrim removed for
clarity.
[0058] FIG. 2B is a fragmentary diagrammatic vertical section taken
through a portion of the apparatus of FIG. 1 illustrating the
endless loop of the transfer belt used in the apparatus.
[0059] FIG. 3 is a fragmentary diagrammatic side elevation of the
apparatus shown in FIG. 1.
[0060] FIG. 4 is an enlarged fragmentary section taken along line
4-4 of FIG. 3.
[0061] FIG. 5 is an enlargement of a portion of FIG. 4.
[0062] FIG. 6 is an enlarged fragmentary section taken along line
6-6 of FIG. 3.
[0063] FIG. 7 is an enlarged section taken along line 7-7 of FIG.
3.
[0064] FIG. 8 is an enlarged fragmentary section taken along line
8-8 of FIG. 3.
[0065] FIG. 9 is an enlarged fragmentary section taken along line
9-9 of FIG. 8 and being rotated ninety degrees.
[0066] FIG. 10 is an enlarged fragmentary section taken along line
10-10 of FIG. 9.
[0067] FIG. 11 is an enlarged fragmentary section taken along line
11-11 of FIG. 8 and having been rotate ninety degrees.
[0068] FIG. 12 is an enlarged fragmentary section taken along line
12-12 of FIG. 3.
[0069] FIG. 13 is an enlarged fragmentary section taken along line
13-13 of FIG. 3.
[0070] FIG. 14 is an enlarged fragmentary section taken along line
14-14 of FIG. 13.
[0071] FIG. 15 is a further enlarged sectional view similar to FIG.
13.
[0072] FIG. 16 is an enlarged fragmentary section taken along line
16-16 of FIG. 4.
[0073] FIG. 17 is an enlarged fragmentary isometric looking
downwardly on the downstream end of the weft yarn application
station and with parts broken away for clarity.
[0074] FIG. 18 is a fragmentary isometric similar to FIG. 17 only
further enlarged.
[0075] FIG. 19 is an enlarged fragmentary section taken along line
19-19 of FIG. 3.
[0076] FIG. 20 is an enlarged fragmentary section taken along line
20-20 of FIG. 19.
[0077] FIG. 21 is an enlarged fragmentary section taken along line
21-21 of FIG. 3.
[0078] FIG. 22 is an enlarged fragmentary section taken along line
22-22 of FIG. 3.
[0079] FIG. 23 is a fragmentary isometric view of a nonwoven fabric
material made with the apparatus illustrated in FIG. 1.
[0080] FIG. 24 is a fragmentary isometric similar to FIG. 23 of a
second embodiment of a fabric manufactured with the apparatus of
FIG. 1.
[0081] FIG. 25 is a fragmentary isometric of a third embodiment of
a fabric manufactured with the apparatus of FIG. 1.
[0082] FIG. 26 is a fragmentary isometric of a fourth embodiment of
a fabric manufactured with the apparatus of FIG. 1.
[0083] FIG. 27 is a vertical section taken through the fabric of
FIG. 24 with the fabric being inverted.
[0084] FIG. 28 is a sectional view taken through the warp yarns of
the nonwoven fabric of the present invention with adhesive being
shown on the radially outermost surface of the yarns.
[0085] FIG. 29 is a fragmentary isometric of a fifth embodiment of
a nonwoven fabric made with the apparatus of FIG. 1.
[0086] FIG. 30 is a fragmentary vertical section taken through the
apparatus of FIG. 1 immediately downstream of the weft yarn
application station showing an alternative control system for
laying the weft yarns across the warp yarns.
[0087] FIG. 31 is a fragmentary section taken along line 31-31 of
FIG. 30.
[0088] FIG. 32 is an enlarged fragmentary section taken along line
32-32 of FIG. 33.
[0089] FIG. 33 is an enlarged fragmentary section taken along line
33-33 of FIG. 32.
[0090] FIG. 34 is an enlarged fragmentary section taken along line
34-34 of FIG. 32.
[0091] FIG. 35 is an enlarged fragmentary section taken along line
35-35 of FIG. 30.
[0092] FIG. 36 is a fragmentary isometric view looking downwardly
on the control system of FIG. 30.
[0093] FIG. 37 is a diagrammatic side elevation of the apparatus of
FIG. 1.
[0094] FIG. 38 is a diagrammatic side elevation of the apparatus of
FIG. 1 with an alternative take-up system to that illustrated in
FIG. 37.
[0095] FIG. 39 is a diagrammatic side elevation of the apparatus of
FIG. 1 showing an alternative supply system for the warp yarns and
adhesive scrim to that of FIG. 37.
[0096] FIG. 40 is an enlarged fragmentary section taken along line
40-40 of FIG. 1 B.
[0097] FIG. 41 is an enlarged fragmentary section taken along line
41-41 of FIG. 1 B.
[0098] FIG. 42 is a diagrammatic side elevation of the warp yarn
material manufacturing unit.
[0099] FIG. 43 is a top plan view of the manufacturing unit shown
in FIG. 42 with portions removed for clarity.
[0100] FIG. 44 is a front end elevation of the apparatus of FIG.
43.
[0101] FIG. 45 is an enlarged section taken along line 45-45 of
FIG. 43.
[0102] FIG. 46 is an enlarged fragmentary section taken along line
46-46 of FIG. 45 with parts removed for clarity.
[0103] FIG. 47 is an enlarged fragmentary section taken along line
47-47 of FIG. 46.
[0104] FIG. 48 is an enlarged fragmentary section taken along line
48-48 of FIG. 46.
[0105] FIG. 49 is an enlarged fragmentary section taken along line
49-49 of FIG. 46.
[0106] FIG. 50 is an enlarged fragmentary section taken along line
50-50 of FIG. 45.
[0107] FIG. 51 is an enlarged fragmentary section taken along line
51-51 of FIG. 50.
[0108] FIG. 52 is a diagrammatic side elevation of the preferred
warp yarn material alignment unit;
[0109] FIG. 53 is a top plan view of the warp yarn material
alignment unit shown in FIG. 52 with portions removed for
clarity;
[0110] FIG. 54 is a front end elevation of the apparatus of FIG.
53;
[0111] FIG. 55 is a partial cross-sectional view of the preferred
warp yarn alignment unit and the hot melt adhesive applicator and
cooling section, with parts removed for clarity;
[0112] FIG. 56 is an enlarged fragmentary section taken along line
B-B of FIG. 55 with parts removed for clarity;
[0113] FIG. 57 is an elevational view of the preferred Rototherm
hot melt adhesive roll coater, showing the exit path of the
adhesive coated warp yarn material;
[0114] FIG. 58 is another elevational view the preferred Rototherm
hot melt adhesive roll coater, shown in the unengaged position,
showing the exit path of the adhesive coated warp yarn
material;
[0115] FIG. 59 is an elevational view of a preferred warp yarn
alignment apparatus; with the beam station; yarn alignment station;
adhesive applicator station and cooling station;
[0116] FIG. 60 illustrates the gravure coating of adhesive on one
side of the aligned warp yarns;
[0117] FIG. 61A is a magnified illustration of the adhesive applied
side of the warp yarn fabric showing the applied adhesive (dark
color) and the bridges holding the fibers in a nontwisting and
parallel relationship;
[0118] FIG. 61B is a magnified illustration of the uncoated side of
the warp yarn fabric, confirming that the parallel fibers have
little adhesive which passes through to the surface opposite that
of FIG. 61A;
[0119] FIG. 62 is a diagrammatic side elevation of a preferred
embodiment of the weft yarn application (XD) apparatus of the
present invention;
[0120] FIG. 63 is a fragmentary diagrammatic top elevation of the
apparatus shown in FIG. 62 with the adhesive removed for
clarity;
[0121] FIG. 64 is a fragmentary diagrammatic side elevation of the
apparatus shown in FIG. 62;
[0122] FIG. 65 is an enlarged fragmentary section taken along line
8-8 of FIG. 64;
[0123] FIG. 66 is an enlarged fragmentary section taken along line
9-9 of FIG. 65 and being rotated ninety degrees;
[0124] FIG. 67 is an enlarged fragmentary section taken along line
10-10 of FIG. 66;
[0125] FIG. 68 is an enlarged fragmentary section taken along line
11-11 of FIG. 65 and having been rotate ninety degrees;
[0126] FIG. 69 is a side cutaway of the conical aligner showing how
the weft yarns are delivered to the warp yarn surface in a tightly
packed arrangement;
[0127] FIG. 70 is a perspective view showing the weft yarns being
applied at wide spacing to the warp yarn cylinder, showing how the
weft yarns slide down the conical aligner face to drop precisely
down on the warp yarn material;
[0128] FIG. 71 is a side view of a preferred embodiment of the
pressure box and drive belt system for the laminator of the
invention in which eight heater bars (four in each section) and
eight cooling bars (four in each section) are used for pressure
lamination of nonwoven fabric substrates;
[0129] FIG. 72 is an end view of the pressure box of FIG. 71, which
shows the pressure delivery system for the upper and lower sections
of the pressure box;
[0130] FIG. 73 is a top view of the upper section of the pressure
box of FIG. 71, showing the spacing of the heating and cooling
bars;
[0131] FIG. 74 is a side view of the pressure box of FIG. 71,
showing the mounting brackets for the upper section (displaceable)
heating and cooling bars and the mounting brackets for the lower
section (fixed) heating and cooling bars. Also shown is one
embodiment of a side sealing element;
[0132] FIG. 75 illustrates the side pressure seal of FIG. 74 in
greater detail;
[0133] FIG. 76 is a side view of the pressure box of FIG. 71,
showing the pressure box inlet pressure seal element; and
[0134] FIG. 77 is a side view of the pressure box of FIG. 71,
showing the pressure box outlet pressure seal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0135] The present invention includes three principal nonwoven
fabric manufacturing apparatus, all of which can be used either
separately for the production of nonwoven fabric products and/or
preferably which are used in combination for the manufacture of
high quality, high strength, nonwoven fabrics having the hand and
appearance of woven fabrics. The present invention generally
consists of (1) a warp yarn alignment apparatus, which has two
especially preferred embodiments, as well as the nonwoven fabric
products generated thereby; (2) a weft yarn application apparatus
(or XD apparatus), which has two especially preferred embodiments,
as well as the nonwoven fabric products generated thereby; and (3)
a high pressure lamination apparatus which can be used to fuse the
product generated in the XD apparatus into fray resistant, high
strength nonwoven fabric. Some of the embodiments described in
detail below have additional and/or alternative component parts,
all of which contribute special characteristics to the nonwoven
fabric products manufactured by the apparatus.
[0136] One preferred embodiment of the nonwoven fabric
manufacturing apparatus 60 is shown in FIG. 1 to include an
elongated in-line framework 62 including a warp yarn material
supply station 64, a weft yarn application station 66, a heating
station 68, a cooling station 70, a flattening station 72 that may
include a flat bed laminator 74 (FIG. 1B), and a take up station
76. As will be described in more detail hereafter a warp yarn
material 78 is provided on a supply roll 80 at the warp yarn
material supply station. The warp yarn material is prepared in a
warp yarn material manufacturing unit, two of which are described
in greater detail below.
Warp Yarn Substrates and Manufacturing Apparatus Therefor
[0137] One preferred nonwoven fabric of the present invention has
parallel yarns held in a substantially parallel and nontwisting
relationship in the form of a nonwoven, fabric-like sheet. Such
materials are referred to herein as warp yarn substrates, and two
manufacturing units for the formation of such substrates have been
developed. In each case, adhesive is applied to one side of the
parallel yarns. The adhesive is advantageously applied in a random
pattern, forming bridges of adhesive between parallel yarns. These
adhesive bridges provide the backbone of the warp yarn substrate,
giving it fabric-like flexibility and feel. The bridges also hold
the parallel positioning of the fibers and prevent twisting of
individual fibers.
[0138] One preferred warp yarn manufacturing unit is illustrated in
FIGS. 42 through 51. As illustrated therein, the warp yarn material
manufacturing unit 82 includes a supply of warp yarn 84 which is
passed through an alignment station 86 into an adhesive application
station 88 and then to a driven transfer roll 90 which acts as a
rewind roll on the warp yarn apparatus and as an unwind roll on the
weft yarn (XD) apparatus, as described below. The transfer roll can
also be the supply roll for the warp yarn material supply station
64 of the nonwoven fabric manufacturing apparatus. The transfer
roll 90 is taken to the warp yarn material supply station of the
nonwoven manufacturing apparatus of FIG. 1 where the warp yarn
material is introduced to the remainder of the apparatus. Of
course, the manufacturing unit 82 and the manufacturing apparatus
60 could be integrated thereby avoiding the transfer roll 90 by
passing the warp yarn material 78 directly from the manufacturing
unit to the supply station.
[0139] The warp yarn material manufacturing unit 82 shown in FIGS.
42 through 51 includes a framework 92 for the warp yarn alignment
station 86 and the adhesive application station 88 where an
adhesive is applied to the aligned warp yarns to create a warp yarn
and adhesive laminate referred to as the warp yarn material 78. It
will be appreciated with the description that follows that at least
one embodiment of the nonwoven product of the invention is not made
from independent warp yarns, but rather is made from a substrate
simply having a majority of interconnected fibers primarily
oriented in the warp or machine direction. One such type of
substrate that has these characteristics is a bonded, carded web
although other substrates may be used including, but not limited
to, spunbonded nonwovens, air-laid nonwovens, and wetlaid
nonwovens. In the event that a substrate that simply includes
interconnected warp fibers is used, the substrate would not be
passed through the warp alignment station 86 of the warp yarn
material manufacturing unit but rather directly to the adhesive
application station 88.
[0140] The warp yarn material manufacturing unit 82 further
includes a yarn supply station 94 which holds multiple horizontally
and rotatably stored beams 96 of roughly aligned warp yarns which
are ultimately integrated into the warp yarn material. It will be
appreciated that the multiple beams of yarns are provided to
achieve a desired warp yarn density which is preferably about 40 to
90 yarns per inch. Each beam of yarn is rotatably positioned and
supported on a frame 98 in the manufacturing unit and restricted
from freely rotating through use of a conventional brake or
friction drag system 100 to allow proper feed of the yarns under
tension into the alignment station. The yarns are pulled through
the alignment station by the driven transfer roll 90.
[0141] The alignment station 86 includes two vertically displaced
sets 102 and 104 of horizontally spaced rollers 106. The upper set
102 is within a horizontal plane positioned above a horizontal
plane containing the lower set 104 of rollers, although it is
conceivable that the orientation of the sets of rollers are not an
upper and lower set but possibly a left and right set or somewhere
in between so that the planes of the sets of rollers would be
horizontally rather than vertically displaced or somewhere in
between. The rollers 106 are transversely aligned with each other.
Further, when the rollers are in horizontal planes the rollers in
each set are horizontally offset from the rollers in the other set
so that the rollers in each set are positioned between rollers of
the other set and the outer perimeter of the rollers in one set
vertically overlaps the outer perimeter of the rollers in the other
set. In this manner, the warp yarns which pass transversely through
the sets of rollers must pass under the upper set of rollers 102
and over the lower set of rollers 104 in a generally sinusoidal, or
serpentine path as seen in FIG. 45. The warp yarns in the preferred
embodiment arcuately engage approximately 20 degrees of each
roller. The yarns could contact more or less of each of the rollers
and the amount of contact could vary from roller to roller within a
row of rollers. The preferred roller diameter is about 2 inches,
though this diameter does not appear to be critical. In the
illustrated embodiment there are 10 rollers in each set even though
varying numbers of rollers might be used. If desired, these rollers
could be heated and/or cooled, which could be used to impart
desirable characteristics to the yarns.
[0142] As can be appreciated in FIG. 46, the peripheral surface of
the rollers 106 nearest to the yarn supply station 94 preferably
have a coarser surface texture than the rollers closest to the
adhesive application station 86. It will be appreciated that the
surface roughness of the rollers, preferably, gradually decreases
from the supply station to the adhesive application station. The
surface texture of the coarsest roller would preferably be finer
than 600 grit sandpaper and more particularly it is estimated that
it would be similar to 1000 grit sandpaper. The surface texture is
very fine and is provided by the use of materials similar to those
used in a conventional ceramic Analox roll. The material used to
provide the surface texture is a ceramic coating LC-4 provided by
Praxair Surface Technologies of New Haven, Conn. In at least one
embodiment the rollers 106 positioned at the exit end of the
alignment station 86 closest to the adhesive application station 88
are actually polished and, therefore, have a very smooth surface
texture.
[0143] The rollers are rotatively driven by a drive system 108 to
rotate about their longitudinal axes. The surface speed of the
alignment rollers 106 is substantially greater than the linear
speed of the warp yarns as they pass through the yarn aligner. The
preferred ratio is about 20:1 with the roller surface speed at
about 300 to 500 feet per minute and the warp yarn linear speed at
about 20 feet per minute. Because the roller surface speed is so
much greater than the linear yarn speed, it is easy to understand
why the warp yarn beams 96 must be restricted from freely rotating
to prevent yarn overrun. Other degrees of yarn/roller contact,
roller speeds, roller to yarn ratios, surface textures, and surface
texture gradients could be used. These parameters will be affected
by at least yarn type, yarn size, and yarn material. It is believed
that over driving the yarns relieves tension and causes the yarns
to relax and expand, while the texture on the surface of the rolls
106 causes the yarns to vibrate and shake causing them to hit their
neighbor yarns thereby ultimately finding a home position
approximately equidistant from each of their neighboring yarns.
This home position is believed to be the equilibrium position
between adjacent yarns. At present it is only conjecture as to why
the yarns align in the yarn aligner, what is known is that the
yarns do become substantially aligned as illustrated in FIGS. 46
through 49.
[0144] While one preferred system for aligning the warp yarns has
been described, another system would be to use conventional combs
to separate and align the yarns. The system used for aligning the
warp yarns does not affect the weft yarn alignment but may affect
the aesthetics of the nonwoven product. After the yarns pass
through the warp yarn alignment station 86 they pass into the
adhesive application station 88. The adhesive application station
in one preferred embodiment comprises an adhesive scrim or lace web
supply roll 110 having a conventional braking or friction drag
system (not shown) to prevent free rotation and thus overrun, an
adhesive scrim or lace counter-clockwise rotating and driven
carrier roll 112, and an infrared heater 114 adjacent to the
carrier roll. The adhesive web 116 passes from its supply roll 110
beneath a first idler roller 118 (FIGS. 45 and 50) and subsequently
onto the upper half of the adhesive carrier roll 112 moving in an
upstream direction. While on the carrier roll, the adhesive web
passes under the infrared heater 114 (as best seen in FIG. 45)
where it is heated to a temperature that begins to melt the
adhesive so as to render it tacky. The adhesive carrier roll itself
is internally cooled in a conventional manner with a liquid coolant
120 for example, so that only the outer surface of the adhesive web
is activated and becomes tacky. Once tacky, the adhesive web 116 is
combined or merged into the warp yarns 84 which are fed downwardly
onto the underside of the carrier roll. The adhesive web has
sufficient structural integrity to act as a carrier for the yarns,
once bonded thereto, and retains the yarns in parallel, nontwisting
relationship. The resultant laminate of warp yarns and adhesive is
defined as one embodiment of the warp yarn material. The warp yarn
material passes across the top of a second idler roller 122 (FIGS.
45 and 50) and is thereafter drawn onto the driven take-up or
supply roll 90 for the warp yarn material where it is gathered for
transfer to the supply station 64 of the nonwoven manufacturing
apparatus 60. While the warp yarn material manufacturing unit 82
has been described as being separated from the apparatus 60 of the
present invention, it is to be understood that the manufacturing
unit could be integrated into the remainder of the apparatus at the
warp yarn material supply station 64 of the apparatus.
[0145] A preferred adhesive scrim or lace web 116 is a hot melt
adhesive that can be heated to activate and cooled to set. An
example is made from a hotmelt copolyester polymer. One such scrim
or lace is a Bostic PE 120-15 Copolyester web with a basis weight
of 15 grams per square meter, it is produced by the Bostic Company
of Middleton, Mass. The warp yarn, by way of example, may be a 36/1
spun polyester yarn available from Burlington Industries of
Greensboro, N.C., or from Carolina Mills of Maiden, N.C. The warp
yarns 84 disclosed above can also be used as the weft yarns in a
manner to be described later. Another warp or weft yarn may be a
30/1 slub yarn (spun polyester) available from Uniblend Spinners
Inc. of Conway, S.C. Other warp and weft yarns include commercially
available and custom made fibers and the like.
[0146] As mentioned previously, a nonwoven substrate such as a
bonded, carded web (not shown) could be used in lieu of the warp
yarns 84 in the laminate structure of the warp yarn material. One
such nonwoven substrate is manufactured by Hollingsworth and Vose
of Floyd, Va. and identified by Model No. TR2232. Such a nonwoven
should have a basis weight between 40-60 grams per square meter
with a fiber denier between 1 to 5 and preferably about 1.5.
[0147] An especially preferred embodiment of the warp yarn material
manufacturing unit of the present invention is shown in FIGS. 52
through 60. FIG. 61A shows the detailed relationship between the
aligned warp yarns 84 and the hot melt adhesive film 116B which
holds the yarns together in a cohesive product. As illustrated in
FIGS. 52 through 60, the warp yarn manufacturing unit 82 includes a
yarn supply station 94 which holds multiple horizontally and
rotatably stored beams 96 of roughly aligned warp yarns which will
ultimately be integrated into the warp yarn material. It will be
appreciated that the multiple beams of yarns (preferably formed
with equal tension in all yarns) are provided to achieve a desired
warp yarn density which may range from about 10 to about 180 yarns
per inch, and preferably range from about 40 to 90 yarns per inch.
The yarn density range could be larger or smaller, depending upon
the desired characteristics of the nonwoven material, as well as
the denier and surface characteristics of the yarns used. Each beam
of yarn is rotatably positioned and supported on a frame 98 in the
manufacturing unit and restricted from freely rotating through use
of a conventional brake or friction drag system 100 to allow proper
feed of the yarns under tension into the alignment station. The
yarns are pulled through the alignment station by the driven
transfer roll 90.
[0148] As illustrated in FIG. 55 the alignment station 86 includes
two vertically displaced sets 102 and 104 of horizontally spaced
rollers 106. The upper set 102 is within a horizontal plane
positioned above a horizontal plane containing the lower set 104 of
rollers, although it is conceivable that the orientation of the
sets of rollers are not an upper and lower set but possibly a left
and right set or somewhere in between so that the planes of the
sets of rollers would be horizontally rather than vertically
displaced or somewhere in between. The rollers 106 are transversely
aligned with each other. Further, when the rollers are in
horizontal planes the rollers in each set are horizontally offset
from the rollers in the other set so that the rollers in each set
are positioned between rollers of the other set and the outer
perimeter of the rollers in one set vertically overlaps the outer
perimeter of the rollers in the other set. In this manner, the warp
yarns which pass transversely through the sets of rollers must pass
under the upper set of rollers 102 and over the lower set of
rollers 104 in a generally sinusoidal, or serpentine path as seen
in FIG. 55. The warp yarns in the preferred embodiment arcuately
engage approximately 20 degrees of each roller. The yarns could
contact more or less of each of the rollers and the amount of
contact could vary from roller to roller within a row of rollers.
The preferred roller diameter is about 2 inches, though this
diameter does not appear to be critical. In the illustrated
embodiment there are 20 rollers in each set even though varying
numbers of rollers might be used.
[0149] As can be appreciated in FIG. 56, the peripheral surface of
the rollers 106 nearest to the yarn supply station 94 preferably
have a coarser surface texture than the rollers closest to the
adhesive application station 86. It will be appreciated that the
surface roughness of the rollers, preferably, gradually decreases
from the supply station to the adhesive application station. The
surface texture of the coarsest roller would preferably be finer
than 600 grit sandpaper and more particularly it is estimated that
it would be similar to 1000 grit sandpaper. The surface texture is
very fine and is provided by the use of materials similar to those
used in a conventional ceramic Analox roll. The material used to
provide the surface texture is a ceramic coating LC-4 provided by
Praxair Surface Technologies of New Haven, Conn. In at least one
embodiment the rollers 106 positioned at the exit end of the
alignment station 86 closest to the adhesive application station 88
are actually polished and, therefore, have a very smooth surface
texture. As with the previously described embodiment, if desired,
these rollers can be heated and/or cooled, to impart distinctive
characteristics to the yarns.
[0150] The rollers are rotatively driven by a drive system 108 to
rotate about their longitudinal axes. The surface speed of the
alignment rollers 106 is substantially greater than the linear
speed of the warp yarns as they pass through the yarn aligner. The
preferred ratio is from about 2:1-3:1 with the roller surface speed
at about 200 to 300 feet per minute and the warp yarn linear speed
at about 100 feet per minute. Because the roller surface speed is
so much greater than the linear yarn speed, it is easy to
understand why the warp yarn beams 96 must be restricted from
freely rotating to prevent yarn overrun. Other degrees of
yarn/roller contact, roller speeds, roller to yarn ratios, surface
textures, and surface texture gradients could be used. These
parameters will be affected by at least yarn type, yarn size, and
yarn material.
[0151] It is believed that over-driving the yarns relieves any
tension in the yarns and causes the yarns to relax and expand,
while the texture on the surface of the rolls 106 causes the yarns
to vibrate and shake causing them to hit their neighbor yarns
thereby ultimately finding a home position approximately
equidistant from each of their neighboring yarns. This home
position is the equilibrium position between adjacent yarns. At
present it is only conjecture as to why the yarns align in the yarn
aligner, what is known is that the yarns do become substantially
aligned as illustrated in FIGS. 47 through 49.
[0152] As best illustrated in FIGS. 60, 61A and 61B, a thin film of
hot melt adhesive is next applied to one side of the aligned yarns,
forming a web of bridges to adjacent aligned yarns. This film is
air cooled and the resulting cohesive warp yarn fabric material is
collected for further use. FIG. 61A is a photograph of the side of
the warp yarn fabric with the bridges of adhesive holding the
fibers in a nontwisting and parallel relationship. FIG. 61B is a
photograph of the uncoated side of the parallel yarns, confirming
that the warp yarn substrate has adhesive on substantially only on
one side of the fibers. As shown in this Figure, some minor amounts
of adhesive may leak through the warp yarn substrate from the side
with the desired bridges. However, substantially all of the
adhesive remains on the side of the aligned yarns to which it is
applied. It is estimated that no more than about 10 percent,
preferably no more than about 5 percent, of the applied adhesive
passes through to the untreated side of the aligned yarns.
[0153] FIGS. 57 through 60 show the preferred adhesive application
unit 88, where the aligned warp yarns 84 are passed through a
series of rollers into contact on one side with hot melt adhesive
coater roller 90. This coater roller 90 is driven through a trough
containing molten hot melt adhesive 116A and a thin (from about
0.25 to 1 mil thick) web of hot melt adhesive is gravure printed on
one side of the aligned warp yarns 84. FIG. 60 illustrates a
simplified version of the application of adhesive to one side of
the aligned yarns with a gravure adhesive roller 90. As
illustrated, the gravure roller picks up melted adhesive 116A and
deposits the adhesive on only one side of the aligned yarns,
forming bridges thereon, which yield a flexible sheet of aligned
yarns once the adhesive has cooled.
[0154] FIG. 58 is a close-up view of the relationship between the
adhesive roller 90, coated with a thin film of hot melt adhesive
116A and the aligned yarn roller 122, which carries the aligned
yarns 84. In this figure, the two rolls are shown in a disengaged
mode. When these two rollers are put in contact with one another,
the exposed side of the aligned yarns 84 is printed or coated with
a thin film of the hot melt adhesive 116A. As the melted hot melt
adhesive 116A cools the aligned yarns are transformed into a
flexible, coherent sheet 116B.
[0155] As shown in FIG. 59, to ensure complete cooling or drying of
the adhesive, the coherent sheet of aligned yarns and adhesive is
passed through a station 95 in which it passes over a series of
rollers to the take-up reel 125. At the take-up reel 125 the
nonwoven warp yarn fabric material is collected, e.g., for further
processing or for use as a nonwoven fabric.
[0156] A preferred adhesive is a hot melt adhesive that can be
heated to activate and cooled to set, for example a hot melt
copolyester polymer. One such adhesive is EMS Grillon 1533
copolyester, produced by EMS Chemie of Sumter, S.C. The warp yarn,
by way of example, may be a 36/1 spun polyester yarn available from
Burlington Industries of Greensboro, N.C., or from Carolina Mills
of Maiden, N.C. Another warp yarn may be a 30/1 slub yarn (spun
polyester) available from Uniblend Spinners Inc. of Conway,
S.C.
[0157] The aligned sheet of warp yarns, bound together on one side
by adhesive bridges, is one especially preferred embodiment of the
present invention. This nonwoven fabric has a unique appearance,
and as described above, it can be manufactured using any number of
different yarns and/or yarn substitutes, including metals such as
copper, silver, gold, platinum, and the like. The bridges formed on
the one side of the aligned yarns hold the material together,
giving it the look and feel of a fabric product.
Weft Yarn Apparatus and Fabrics Formed Thereby
[0158] Two embodiments of the weft yarn apparatus or XD apparatus
are disclosed herein, each of which positions the weft yarns
substantially perpendicular to the aligned warp yarns. One such
apparatus is described in detail in FIGS. 1 through 7. As
illustrated therein, the warp yarn material 78 is passed on an
endless, recycling transfer belt 124, preferably of Teflon.RTM.(R),
along a substantially cylindrical support structure 126 that shapes
the warp yarn material in the general shape of a cylinder with the
warp yarns or yarns in the material being aligned longitudinally
along the length of the substantially cylindrical support surface.
When formed into the cylindrical shape, the warp yarn material is
advanced through the weft yarn application station 66 at a
predetermined rate with the adhesive positioned on the exterior
surface of the cylindrically configured warp yarn material. As the
warp yarn material passes through the weft yarn application
station, a series of weft yarns 128 (as best seen in FIGS. 8,
12-15, 17 and 18) radially located on a rotating drum 130 an equal
distance from one another, are wrapped transversely around the
cylindrically configured warp yarn material at a predetermined rate
and the resultant laminate of warp yarn material 78, adhesive scrim
or lace 116 and weft yarns 128 is then advanced through the heating
station 68 where the adhesive scrim or lace is activated so that
the adhesive bonds the warp yarn material and the weft yarns. It
will be appreciated that as an alternative, adhesive could be
sprayed onto the warp yarns before the weft yarns are laid down.
Immediately thereafter the material passes through the cooling or
adhesive setting station 70 where the adhesive is set so as to no
longer be tacky. As the resultant fabric laminate 131 progresses
from the cooling station to the take-up station 76, a cutter 132,
preferably a rotary cutter, longitudinally severs the cylindrical
laminate and the laminate material progressively changes from its
cylindrical orientation to a generally flat orientation in the
flattening station 72. At the downstream end of the flattening
station, the belt passes down and around a drive roller 133 (FIG.
2B), that underlies the endless belt, where the belt is returned to
the supply station 64 via tensioning roller 135 and idler rollers
137.
[0159] The drive roller, through its driving engagement with the
endless belt, thereby advances the warp yarn material through the
apparatus. Upon passing the drive roller, the laminate material, in
a preferred embodiment, is passed through a flat bed laminator 74,
after which it is wrapped onto a take-up roller 136 at the take-up
station which can be removed from the apparatus when necessary or
at pre-determined intervals. FIG. 2 is another diagrammatic view
looking down on the apparatus shown in FIG. 1. This view
illustrates the longitudinal, or machine direction orientation of
the warp yarn material as it enters the weft yarn application
station 66 and the resultant nonwoven laminate fabric product 131
extending from the weft yarn application station toward the take-up
station 76. As best illustrated in FIGS. 4 through 7, the support
structure 126 extends from the supply station through the weft yarn
application station 66 to the take-up station so as to support the
warp yarn material 78 and ultimately the nonwoven fabric laminate
131 in a desired orientation for processing. The support structure
includes a horizontal beam 138 extending uninterruptedly from the
supply station 64 to the take-up station 76. The horizontal beam is
covered with and supports a rigid foam 140 or other desirable
material that will maintain its shape and configuration over time.
The foam is a rigid polyurethane foam manufactured by Great Stuff
and distributed through Home Depot centers throughout the United
States. The foam is typically used for insulating window casements.
At the supply station, and as best seen in FIGS. 4 and 5, the foam,
which has an outer low friction covering 142 defines a flat upper
surface and as the body of foam progresses toward the weft yarn
application station 66, the outer covering progressively transforms
into a substantially cylindrical configuration. As seen in FIG. 6,
at an intermediate location between the supply station and the weft
yarn application station, the outer covering of the foam is
somewhat semi-cylindrical but as it reaches the weft yarn
application station as seen in FIG. 7, the outer covering is
substantially cylindrical. The reverse transformation of the outer
covering occurs from the weft yarn application station to the drive
roller 133 for a purpose to be described later.
[0160] The supply of warp yarn material 78 is disposed on the
transfer roll 90 at the supply station and the yarns or fibers in
the material 78 extend in parallel side-by-side relationship. A
suitable braking or friction system (not seen) prevents the roll
110 from rotating freely and thus overrunning. The material is
passed over an idler roller 144 onto the driven, endless recycling
Teflon.RTM. belt 124 that supports the warp yarn material and
advances it through the weft yarn application station. The
Teflon.RTM. belt conforms to the support structure 126 and slides
over a stainless steel wear plate that acts as the outer covering
142 of the foam body 140. When the warp yarn material is first fed
onto the belting surface as seen in FIG. 4, the yarns or fibers of
the material are positioned in parallel side by-side relationship
and extend longitudinally of the apparatus. FIG. 4 also shows the
layer of adhesive scrim or lace 116 of the material overlaid on the
warp yarn material as the material progresses onto and along the
belting. As will be seen in FIG. 6, as the warp yarn material
progresses through the apparatus, it is supported and carried by
the Teflon.RTM. belt along the support structure. It initially
assumes an arcuate downwardly concave orientation and, finally,
when it approaches the weft yarn application station as shown in
FIG. 7, it assumes a substantially cylindrical configuration with
only a small longitudinal gap at the bottom of the cylinder.
[0161] As seen in FIG. 8, at the weft yarn application station 66,
the foam body 140 and stainless steel wear plate or covering 142
are interrupted but the Teflon.RTM. belting 124 continues through
the weft yarn application station and is supported by a rigid inner
cylindrical ring 144 that extends substantially the full length of
the weft yarn application station. The cylindrical ring 144 is
almost contiguous with the foam 140 and, in essence, forms a
continuation of the foam body through the weft yarn application
station with only a small gap existing as the Teflon.RTM. belting
and warp yarn material are fed through the center of the weft yarn
application station.
[0162] The weft yarn application station 66, as probably best seen
in FIGS. 8 and 17, includes an outer housing 146 having a front or
upstream wall 148 with a central circular opening 150 there
through, a rear or downstream wall 152 having an aligned circular
opening 154 there through, a top wall 156, a bottom wall 158, and
side walls 160. As best seen in FIG. 8, a rigid support ring 162
having a peripheral flange 164 at its upstream end is bolted or
otherwise secured to the rear wall 152 of the housing and defines a
cylindrical passage 166 through the weft yarn application station.
An inner cylindrical surface of the support ring is
circumferentially spaced from the belting as it extends through the
weft yarn application station. The support ring carries at
longitudinally spaced locations on its outer surface the inner
races of large diameter thin section ball bearings 168 such as of
the type provided by Kaydon Corp. of Sumter, S.C. Outer races of
the ball bearings respectively support another cylindrical body 170
that forms the inner cylindrical wall of the rotating drum. The
inner cylindrical wall of the rotating drum supports a front radial
wall 172 at the upstream end of the drum and rear radial wall 174
at the downstream end of the drum, and the radial walls support an
outer cylindrical wall 176 of the drum. The rear radial wall 174
has concentric ring-like portions defining an inner ring plate 175
and an outer ring plate 177. The inner ring plate is secured by
fasteners to the ends of the inner cylindrical wall 170 and the
outer ring plate is secured with fasteners to an annular flange 179
secured to the inner cylindrical wall 170, as best seen in FIG. 14.
A variable speed electric motor 178, serving as power means for the
weft yarn application station, is mounted on the upstream face of
the front wall 148 of the housing and has a drive shaft 180 that
extends into the interior of the housing and supports a drive
pulley 182 that is aligned with one of the ball bearings 168. The
inner cylindrical wall 170 supports a pulley 186 around which a
drive belt 188 extends so as to operably interconnect the drum with
the drive pulley 182 of the electric motor. Energization of the
electric motor thereby rotates the drum at variably selected
speeds. The details of the mounting of the ball bearing and drive
belt are probably best seen in the enlarged view in FIG. 10.
[0163] The rear or downstream radial wall 174 of the rotating drum
consists of a circular plate having a plurality (in the disclosed
embodiment six) of circumferentially spaced circular openings 190
there through. A peripheral seat 192 passes around each opening so
that a disk-like closure plate 194 can be seated in the seat to
selectively close the opening. Thumb screw fasteners 196 secure the
disk-like closure plates to the rear wall of the drum for easy
attachment and removal. This relationship is probably best
illustrated in FIGS. 9, 14, 15 and 17. Each disk-like closure plate
194 has an eyelet 198 secured thereto at its geometric center so
that the eyelet is positioned on the inner side of the disk. The
eyelet serves as a guide for the weft yarn material 128, as will be
explained hereafter. A plurality of source supplies of weft yarn
material are provided in the form of spools 200 of such material
and are removably mounted on the inner surface of the front wall
172 of the rotating drum, again in circumferentially spaced
relationship and alignment with the circular openings 190 in the
rear wall of the drum. It should be appreciated that the number of
spools of weft yarn material could vary and while the disclosed
embodiment shows six such spools, more or less could be used, in a
preferred embodiment, twelve such spools are used. The weft yarn
material is extended from a spool 200 to the eyelet 198 on the
associated closure disk 194 and then passed radially inwardly
through a gap 202 between the closure disk and the front wall of
the drum as best seen in FIG. 15. Associated with each closure disk
and in radial alignment therewith is a tensioner 204 for
controlling the tension of the weft yarn material mounted on the
downstream side of the rear wall 174.
[0164] The tensioner 204 as best seen in FIGS. 14, 18 and 31
consists of a threaded rod 206 projecting downstream of the machine
and having a disk-like base 208. A collar 210 is slidably disposed
on the rod and also has a disklike base in confronting relationship
with the disk-like base 212 of the rod. A coil spring 214 is
concentrically mounted on the rod and in engagement with the collar
210 at one end and in engagement with a threaded nut 216 at the
opposite end so that the nut can be threaded onto the rod and
positioned at any selected longitudinal position to vary the
compressive strength of the coil spring. The weft yarn material 128
passes between the base of the rod and the base of the collar and
is allowed to slide there between but in frictional engagement
therewith. The frictional drag on the weft yarn material is
regulated by the compressive strength of the spring.
[0165] Immediately adjacent to the tensioner 204 and in radial
alignment therewith at the innermost edge of the rear wall 174 of
the drum 136 is a guide pin 218 that also projects downstream of
the machine and around which the weft yarn material extends. The
guide pin is positioned immediately adjacent to the warp yarn
material 78, for example, at a gap of about 0.015 inches, though
other gaps could be used. The guide pin thereby allows the weft
yarn 128 to be very accurately applied across the warp yarn
material as the drum is rotated in a manner to be described in more
detail hereafter.
[0166] As best seen in FIG. 18, a plurality of leveling plates 220
of generally L-shaped cross-section are mounted on the downstream
face of the rear wall 174 of the rotating drum immediately adjacent
to an associated tensioner 204 and guide pin 218 and positioned to
the right or in a clockwise direction from the tensioner and guide
pin when looking upstream. The leveling plate is mounted a distance
approximately equal to the thickness of the weft yarns 128 from the
adhesive outer surface of the warp yarn material 78 so as to assure
a uniform level wrap of the weft yarn material onto the adhesive
scrim or lace of the warp yarn material.
[0167] An alternate guide pin in the form of a leveling block 222
is illustrated in FIGS. 30 through 36 It will there be seen that
the leveling block is positioned immediately adjacent to an
associated tensioner 204 which serves both to guide the weft yarn
128 as it is laid down on the warp yarn material 78 and also to
assure that the previous wraps of weft yarn are in a single layer
and packed together as desired. The block 222 provides significant
control over the lay down of the weft yarn material and provides
for accurate placement of the yarns relative to one another. The
weft yarns can be packed very densely up to 140,36/1 cotton count
yarns per inch or they can be placed accurately with no more than a
ten thousandths of an inch difference in the position of one yarn
and the position of the next adjacent yarn.
[0168] The leveling block 222 as best seen in FIG. 36 is generally
L-shaped in transverse cross-section and pivotally mounted to a
ring block 224 (which replaces the inner ring plate 175 described
previously) on the inner periphery of the rear wall 174 of the
rotating drum 130 with a pivot assembly. The pivot assembly as best
seen in FIGS. 30 and 31 includes a pivot shaft 226 that is keyed to
the leveling block and secured thereto with a cap screw 228 with
the pivot shaft being rotatably mounted on a pair of ball bearings
230 mounted within the ring block. The innermost end of the pivot
shaft also has a cap screw 232 secured therein which retains a
compression spring 234 between the end cap and an abutment surface
236 within the ring block. The compressive force of the compression
spring can be regulated with the cap screw and serves to operably
draw the leveling block against a low friction washer 238 to adjust
the ease with which the leveling block is allowed to pivot with the
pivot shaft.
[0169] A coil spring 240 anchored to the rear wall 174 of the
rotating drum 130 and to the leveling block 222 biases the opposite
end of the block against the underlying previously wrapped weft
yarn material 128. This keeps the wraps of weft yarn material in
one uniform level which is desired for the finished nonwoven fabric
product. The leveling block has two legs 242 and 244 which define a
groove 246 at their juncture with the groove confining and
controlling a segment of the weft yarn material 128 as it is
transferred from the associated and adjacent tensioner 204 to the
surface of the warp yarn material 78 in a controlled manner. Of
course, when the leveling blocks are used, the previously described
leveling plates 220 are not necessary.
[0170] An adjustable spacer 248 is mounted on the leveling block
222 and functions to selectively adjust the spacing between the
leveling block and the ring block 224 (FIGS. 30 and 31) so that the
groove 246 in the leveling block can be aligned with the tensioner
204 whereby the weft yarns pass in a straight line through the
tensioner and the groove in the leveling block before being applied
to the adhesive scrim. The adjustable spacer 248, as probably best
seen in FIGS. 30, 35 and 36, includes an L-shaped wedge base 250
having a short leg 252 with a circular passage 254 there through
and a long leg 256 having a slot 258 in its free end so as to
bifurcate the long leg thereby defining a pair of straddling arms
262. The long leg is tapered in cross-section so that it is thicker
at the end adjacent to the short leg 252 and thinner at its free
end 260. The L-shaped base is secured to an end of the leveling
block 222 with an adjustable cap screw 264 that passes through the
passage 254 in the short leg such that the short leg is captured
between the head 266 of the screw and a fixed washer 268 on the
screw. The screw is threadably received in a threaded hole 270 in
the end of the leveling block and is adjustable therein so that as
the screw is advanced into or backed out of the threaded hole in
the leveling block, the L-shaped base is slidably moved relative to
the pivot shaft 226. The slot 258 in the long leg straddles the
pivot shaft so that the arms 262 are positioned above and below the
pivot shaft. Sliding movement of the L-shaped arm along the length
of the long leg 256 between the leveling block and the ring block
causes the spacing between the leveling block and the ring block to
be adjusted as the cap screw 264 is moved into or out of the
threaded hole. The L-shaped base is preferably made of a low
friction material that interfaces with the low friction washer 238
previously described so that the leveling block freely pivots
relative to the ring block as desired.
[0171] The heating or adhesive activating station 68 consists of a
steel or other heat transmitting cylindrical core 272 that is
positioned interiorly of the belt 124 immediately downstream from
the weft yarn material application station 66 and forms an axial
extension of the rigid cylindrical ring 162 in the weft yarn
application station. Resistive heat elements 274 are
circumferentially positioned around the steel core 272 with the
resistive heat elements connected to an electrical source by wiring
276 as possibly best seen in FIGS. 8 and 10, which passes through
the cylindrical ring support in the weft yarn application station
and outwardly of the apparatus through a circular aperture 278
therein so that it can be plugged into an electrical power source
in a conventional manner. When an electrical current is applied to
the resistive elements, the metal core 272 is heated thereby
radiating heat outwardly through the warp yarn material, the
adhesive scrim or lace of the warp yarn material, and the overlying
layer of weft yarn material. The heat is controlled to sufficiently
activate the adhesive in the adhesive scrim to bond the warp and
weft yarns together. In addition to the heating and cooling means
described herein, the skilled artisan can select other heating and
cooling means, e.g., steam heat and cooling water mist, could be
employed.
[0172] As the composite material 131 of bonded warp and weft yarns
is moved downstream, it next encounters the cooling or adhesive
setting station 70 which, again, includes a steel or other heat
conductive cylinder 280 which immediately underlies the belt 124. A
heat transfer system 282 interiorly of the cylinder 280 uses
circulating coolant from inlet and outlet tubes 284, respectively,
in a conventional manner to remove heat from the composite
material. The coolant transfer tubes which are seen in FIG. 19, for
example, are connected to the heat transfer system so that a
continuous supply of coolant fluid can be circulated through the
cooling station to set the adhesive of the scrim or lace thereby
securely bonding the warp and weft yarn material.
[0173] As the composite fabric material 131 leaves the cooling
station 70 and is moved further downstream, it engages the fabric
cutter 132 that is conventional and is mounted on a bracket 286
immediately beneath the foam support 140. The cutter serves to
sever the composite material 131 of warp and weft yarn material
along its length as it is moved along the apparatus. Heat or
ultrasonic means (not shown) can also be used to fuse the severed
edges of the fabric material as it is being cut.
[0174] As the composite fabric material progresses further
downstream after being cut, it is flattened out as the support
structure 126 transgresses from a cylindrical configuration to a
flat configuration in the flattening station 72. Accordingly, as
the nonwoven fabric material reaches the drive roller 133 and then
passes to the take-up station 76, it has been flattened on the belt
124 and is wrapped around the take-up roll 136 until a desired
amount of fabric material has been accumulated. The take-up roll
can then be removed from the machine and replaced with another
take-up roller to continue the process.
[0175] The resulting nonwoven fabric has both warp and weft yarns,
secured by adhesive which contacts only a portion of the individual
yarns, i.e., by yarn to yarn, or point to point contact. No yarns
in the product are intentionally coated completely with adhesive.
This factor preserves the feel of the nonwoven fabric as being more
akin to a woven fabric. This nonwoven fabric material is another
especially preferred embodiment of the present invention.
[0176] To further describe one preferred nonwoven fabric
manufacturing method of the invention and the operation of the
apparatus therefor, a supply roll 90 of warp yarn material that was
prepared in the warp yarn material manufacturing unit 82 is mounted
in the supply station 64 and the warp yarn materials pulled through
the apparatus to the take-up station where it is secured to the
take-up roll 136. The drive roller 133 is rotatively driven by a
motor (not shown) at the same speed as the transfer belt 124 and
the motor is controlled by a control system in box 302 (FIGS. 1-3)
that also serves as the control system for the motor 178 at the
weft yarn application station 66, the heating station 68 and the
cooling station 70. To begin manufacture of the nonwoven fabric
131, after the warp yarns have been aligned and adhesive has been
applied to them, or in the alternative to a nonwoven substrate in
the warp yarn material manufacturing unit 82, to create the warp
yarn material, the drive roller 133 and transfer belt 124 are
driven in conjunction with the take-up roll 136. The Teflon.RTM.
belt 124 supports and moves the warp yarn material along the length
of the apparatus. A braking force (not shown) is applied to the
supply roll of the warp yarn material to facilitate regulating the
tension in the warp yarn material and avoid overruns. The rotating
drum 130 in the weft yarn application station is next activated so
as to rotate in a clockwise direction as viewed upstream in FIGS.
17 and 18. Before advancing the warp yarns and before rotating the
drum, the strands of weft yarn material mounted in the drum are
threaded through the associated eyelets 198, the tensioners 204 and
around the guide pins 218 and initially taped to the warp yarn
material 78. It will, therefore, be appreciated that when the drum
is rotated in the clockwise direction, the various strands of weft
yarn material 128 are wrapped around the warp yarn material, which
is simultaneously being moved linearly through the weft yarn
application station 66 so that the various strands of weft yarn
material are wrapped about the warp yarn material in adjacent
relationship. As will be appreciated, by varying the rate of
rotation of the drum relative to the linear speed of the warp yarn
material passing through the drum, the spacing of the weft yarn
strands can be regulated so that the strands are either positioned
in closely packed contiguous relationship or slightly spaced with
the spacing being variable but precise relative to one another
depending upon the relative speeds of the rotating drum and drive
roll and transfer belt which advances the transfer belt and the
warp yarn material linearly through the drum. Of course, the
greater the ratio of linear speed of warp yarn material to the
rotating speed of the drum, the greater the spacing between wraps
of weft yarn strands.
[0177] As will also be appreciated, since the warp yarn material is
moving linearly in a machine direction, as the weft yarns are
wrapped there around, the weft yarns are not wrapped perfectly
perpendicular to the warp yarns or fibers in the warp yarn material
even though they are substantially so. Again, as the ratio of the
linear speed of the warp yarn material to the rotative speed of the
drum increases, the angle of wrap of the weft yarn material
relative to the length of the warp yarns or fibers decreases. The
angle of wrap might vary anywhere up to slightly more than about
89.7 degrees depending upon the relative differential in speeds. In
other words, when slowing the linear speed of the warp yarn
material relative to the rotative speed of the drum, the yarns can
be wrapped closely together and substantially perpendicular to the
warp yarns or fibers in the warp yarn material (i.e., approaching
90 degrees) but as the linear speed of the warp yarn material is
increased without increasing the rotating speed of the drum, the
angle of wrap decreases down to, for example, about 80-85 degrees.
The angle of wrap is the angle between the longitudinal axis of the
machine and the transverse direction of the weft yarn material.
[0178] As mentioned previously, after the weft yarn material is
wrapped about the adhesive scrim and the underlying warp yarns or
fibers of the warp yarn material, the combined materials pass
through a heating station 68 where the adhesive is activated to a
tacky state such that the warp and weft yarn material are
adhesively bonded or joined together. As the material progresses
further downstream, it passes through a cooling station 70 where
the adhesive is set so as to remove the tacky or sticky nature of
the adhesive but yet the warp and the weft yarns are bonded into a
nonwoven fabric as desired. Further movement of the warp and weft
material along the length of the machine causes the cylindrically
wrapped weft yarns to be cut by the cutter 132 thereby forming a
web of nonwoven fabric material 131 which is flattened out as it
progresses toward the drive roller, a flat bed laminator 74 (if
used), and ultimately the take-up roll 136 (or sheeter, not shown),
by the progressively flattening nature of the support structure 126
on which the material is guided. The material is wrapped around the
take-up roll at the take-up station which can be removed from the
machine when a desired amount of nonwoven fabric material is
wrapped thereon.
[0179] The adhesive scrim or lace 116 of the warp yarn material 78
could come in numerous forms but in a preferred embodiment it is a
web of adhesive strands which have been secured together randomly
providing gaps there between. A suitable adhesive web is
manufactured by Bostic Company of Middleton, Mass. Accordingly,
when the adhesive scrim is activated at the heating station, the
adhesive does not cover the entire surface area of the warp and
weft yarn material but rather preferably has a basis weight that is
about 5-20% of the total weight of the structure. The amount of
adhesive laid down has a direct bearing on the softness and hand of
the nonwoven fabric material manufactured with the above described
apparatus and, of course, this is a variable that is controlled
with the type of scrim or other adhesive material used.
[0180] Another type of adhesive material that could be used is a
meltblown adhesive. A meltblown adhesive web could be purchased, or
a meltblown applicator could be used to blow the adhesive onto the
adhesive support roll of the adhesive applicator for lamination
onto the aligned warp yarns, or the meltblown adhesive could be
blown directly onto the warp yarns. The advantage of a meltblown
adhesive may be the uniformity of the web at the low density of
adhesive basis weight. Since meltblown fibers are micro denier
fibers, a low density, and very uniform web can be created for
bonding the warp yarns to the weft yarns of the nonwoven.
Uniformity of the adhesive web may enhance the appearance of the
nonwoven.
[0181] As mentioned previously, by varying the speed of rotation of
the drum 130 relative to the linear speed of the belt 124, the
wraps of weft yarn material can either be positioned immediately
adjacent and contiguous with each other or in spaced relationship.
This is illustrated, for example, in FIGS. 23 and 24, respectively.
Warp yarns 84 as illustrated in each embodiment are positioned
contiguous with each other but the spacing of the wraps of weft
yarn 128 is varied. FIG. 25 shows an even greater spacing of the
weft yarns 128 relative to the warp yarns 84 and it should be
appreciated, even though it is not evident in the drawings, that
the greater the spacing of the weft yarn wraps, the smaller the
angle of wrap the weft yarns make with the longitudinal axis of the
warp yarns. In other words, as the weft yarns are wrapped closer
and closer together, the angle of wrap of the weft yarn increases
to approach 90 degrees, but as the spacing of the weft yarns
increase, the angle diminishes down to, for example, approximately
80-85 degrees. FIG. 27 is a diagrammatic view illustrating the
adhesive bond between the warp 84 and weft 128 yarns, while FIG. 28
is a diagrammatic view illustrating how the adhesive in the scrim
116 is applied only to the radially outermost surface of the warp
yarns 84.
[0182] FIG. 29 illustrates still another embodiment of a fabric
that can be manufactured with the apparatus of the present
invention and wherein the weft yarn material 128 is of a smaller
denier or diameter than the warp yarns 84. It will be appreciated
that the warp yarns could also be of a smaller denier relative to
the weft yarns. Moreover, mixtures of weft yarns (not shown), for
example yarns of various types (synthetic, natural,
yarn-substitutes) and/or yarns of various deniers, can be applied
as weft yarns using this apparatus, resulting in nonwoven fabric
materials having particularly interesting and unique
properties.
[0183] Another preferred version of the XD apparatus is shown in
FIGS. 62 through 70, and includes an elongated in-line framework
62' including a warp yarn material supply station 64', a weft yarn
application station 66', a heating station 68', a cooling station
70', a flattening station 72', and a take-up station 76'. From the
take-up station, the composite nonwoven fabric of this invention
can either be used directly, for instance as a light filtering
medium, or it can be pressure laminated into a high strength
composite fabric, suitable for use under extreme conditions, e.g.,
as sail cloth fabric. As shown in FIGS. 60 and 62, a warp yarn
material 78' is provided on a supply roll 80' at the warp yarn
material supply station 64'. Once in place at the supply station
64' of the apparatus of the present invention the warp yarn
material 78' is passed on an endless, recycling transfer belt 124',
preferably of PTFE (Teflon.RTM.). A series of bars and folding
points (not shown) convert the flat sheet of warp yarn material and
the belt into a curved or cylindrical shape. This folding box
equipment is known in the art, and once the warp yarn material has
the general shape of a cylinder, with the adhesive layer on the
outside or exposed surface, the warp yarns are ready to be over
wrapped with the weft yarn material.
[0184] Once formed into a cylindrical shape, the warp yarn material
is advanced through the weft yarn application station 66' at a
pre-determined rate with the warp yarn adhesive film positioned on
the exterior surface of the cylindrically configured warp yarn
material. As the warp yarn material passes through the weft yarn
application station, a series of weft yarns 128' radially located
on a rotating drum 130' an equal distance from one another are
wrapped transversely around the cylindrically configured warp yarn
material at a predetermined rate and the resultant composite
structure of warp yarn material 78', adhesive film 116' and weft
yarns 128' is then advanced through the heating station 68' where
the adhesive film is melted so that the adhesive will bond the warp
yarn material and the weft yarns.
[0185] Immediately thereafter, the composite material passes
through the cooling or adhesive setting station 70' where the
adhesive is set so as to no longer be tacky. The bonded fabric
composite 131' progresses from the cooling station to the take-up
station 76', a cutter 132', preferably a rotary cutter,
longitudinally severs the cylindrical composite fabric material and
the cut composite fabric material progressively changes from its
cylindrical orientation, back to a generally flat orientation in
the flattening station 72'. At the downstream end of the flattening
station, the belt passes down and around a drive roller 133' that
underlies the endless belt, where the belt is returned to the
supply station 64' via tensioning roller 135' and idler rollers
137'. The drive roller, through its driving engagement with the
endless belt, thereby advances the warp yarn material through the
apparatus.
[0186] FIG. 63 is another diagrammatic view looking down on the
apparatus shown in FIG. 62. This view illustrates the longitudinal,
or machine direction orientation of the warp yarn material as it
enters the weft yarn application station 66' and the resultant
nonwoven composite fabric product 131' extending from the weft yarn
application station toward the take-up station 76'.
[0187] The supply of warp yarn material 78' is disposed on the
transfer roll 90 at the supply station and the yarns or fibers in
the material 78' extend in parallel side-by-side relationship. A
suitable braking or friction system (not shown) prevents the roll
110' from rotating freely and thus overrunning. The material is
passed over an idler roller 144' onto the driven, endless recycling
PTFE (Teflon.RTM.) belt 124' that supports the warp yarn material
and advances it through the weft yarn application station. The PTFE
(Teflon.RTM.) belt conforms to the support structure 126' and
slides over a stainless steel wear plate.
[0188] As seen in FIG. 65, at the weft yarn application station
66', the PTFE (Teflon.RTM.) belting 124' continues through the weft
yarn application station and is supported by a rigid inner
cylindrical ring 144' that extends substantially the full length of
the weft yarn application station. FIG. 66 illustrates the weft
yarn application station 66' which includes an outer housing 146'
having a rear or downstream wall 152' having an aligned circular
opening 154' there through, a top wall 156', a bottom wall 158',
and side walls 160'. A rigid support ring 162' having a peripheral
flange 164' at its upstream end is bolted or otherwise secured to
the rear wall 152' of the housing and defines a cylindrical passage
166' through the weft yarn application station. An inner
cylindrical surface of the support ring is circumferentially spaced
from the belting as it extends through the weft yarn application
station. The support ring carries at longitudinally spaced
locations on its outer surface the inner races of large diameter
thin section ball bearings 168' such as of the type provided by
Kaydon Corp. of Sumter, S.C. Outer races of the ball bearings
respectively support another cylindrical body 170' that forms the
inner cylindrical wall of the rotating drum. The inner cylindrical
wall of the rotating drum supports a front radial wall 172' at the
upstream end of the drum and radial wheel 194' at the downstream
end of the drum, and the radial walls support an outer cylindrical
wall 176' of the drum. The radial wheel 194' has guide posts 195'
on the outer edges for delivering the weft yarns to the warp ring.
The innermost portion of the radial wheel terminates at the conical
aligner 200, which has a radiused, curved or sloped surface. The
conical aligner 200 guides the weft yarns into a substantially
perpendicular alignment with the warp yarns.
[0189] A variable speed electric motor 178', serving as power means
for the weft yarn application station, is mounted on the upstream
face of the front wall 148' of the housing and has a drive shaft
180' that extends into the interior of the housing and supports a
drive pulley 182' that is aligned with one of the ball bearings
168'. The inner cylindrical wall 170' supports a pulley 186' around
which a drive belt 188' extends so as to operably interconnect the
drum with the drive pulley 182' of the electric motor. Energization
of the electric motor thereby rotates the drum at variably selected
speeds. The details of the mounting of the ball bearing and drive
belt are probably best seen in the enlarged view in FIG. 67.
[0190] A plurality of source supplies of weft yarn material are
provided in the form of spools 206' of such material and are
removably mounted on the inner surface of the front wall 172' of
the rotating drum, again in circumferentially spaced relationship
and alignment with the circular openings 190' in the rear wall of
the drum. It should be appreciated that the number of spools of
weft yarn material could vary and while the disclosed embodiment
shows six such spools, more or less could be used, in a preferred
embodiment, twelve such spools are used. The weft yarn material is
extended from a spool 206' to the eyelet 198' on disk 194' and then
passed radially inwardly down the face of disk 194' to another
eyelet at the base of disk 194'. See, FIG. 68.
[0191] As the weft yarn application drum rotates, the weft yarns
are delivered through guides 204' on disk 194', and the yarns slip
down the curved slope of the conical aligner 200, by which each
yarn is delivered to the warp in a substantially perpendicular
alignment. FIGS. 69 and 70 best illustrate the conical aligner of
the present invention. As shown in FIG. 69 in particular, the
conical aligner 200 is a stationary device, with a surface angle or
slope which faces the direction of travel of the warp yarn
materials. The weft yarns are delivered to the surface of the
conical aligner by rotatory pulleys operating in conjunction with
the rotating drum. As with the previously described XD embodiment,
mixtures of weft yarns (not shown), for example yarns of various
types (synthetic, natural, yarn-substitutes) and/or yarns of
various deniers, can be applied as weft yarns using this apparatus,
resulting in nonwoven fabric materials having particularly
interesting and unique properties. The individual weft yarns are
each delivered to substantially the same spot on the sloped surface
of the conical aligner. They fall down the sloped surface, and are
forced, one after the other, down into a tight spacing on the
surface of the adhesive coated warp yarns. FIG. 70 shows a
perspective view of the application of weft yarns, in a wide
spacing manner, to the warp yarns. FIGS. 69 and 70 are perspective
views showing the conical aligner 200 from the right and left sides
respectively. Once the weft yarns have been applied to the warp
yarn material, the adhesive between the yarns must be heated and
cooled to form a nonwoven fabric. These steps are conducted in the
next part of the apparatus as discussed below.
[0192] The adhesive heating station 68' consists of a steel or
other heat transmitting cylindrical core 272' that is positioned
interiorly of the belt 124' immediately downstream from the weft
yarn material application station 66' and forms an axial extension
of the rigid cylindrical ring 162' in the weft yarn application
station. Resistive heat elements 274' are circumferentially
positioned around the steel core 272' with the resistive heat
elements connected to an electrical source by wiring 276' which
passes through the cylindrical ring support in the weft yarn
application station and outwardly of the apparatus through a
circular aperture 278' therein so that it can be plugged into an
electrical power source in a conventional manner. When an
electrical current is applied to the resistive elements, the metal
core 272' is heated thereby radiating heat outwardly through the
warp yarn material, the adhesive on the warp yarn material, and the
overlying layer of weft yarn material. The heat is controlled to
sufficiently melt the adhesive to bond the warp and weft yarns
together.
[0193] As the composite fabric material 131' of bonded warp and
weft yarns is moved downstream, it next encounters the cooling or
adhesive setting station 70 which, again, includes a steel or other
heat conductive cylinder 280' which immediately underlies the belt
124'. A heat transfer system 282' interiorly of the cylinder 280'
uses circulating coolant (e.g., cold water) from inlet and outlet
tubes 284', respectively, in a conventional manner to remove heat
from the composite fabric material. The coolant transfer tubes (not
shown) are connected to the heat transfer system so that a
continuous supply of coolant fluid can be circulated through the
cooling station to set the adhesive thereby securely bonding the
warp and weft yarn material.
[0194] As the composite fabric material 131' leaves the cooling
station 70' and is moved further downstream, it engages the fabric
cutter 132' that is conventional and is mounted on a bracket 286'.
The cutter serves to sever the composite fabric material 131' along
its length as it is moved along the apparatus.
[0195] As the material progresses further downstream after being
cut, it is flattened out as the support structure 126' transgresses
from a cylindrical configuration to a flat configuration in the
flattening station 72'. Accordingly, as the nonwoven composite
fabric material reaches the drive roller 133' and then passes to
the take-up station 76', it has been flattened on the belt 124' and
is wrapped around the take-up roll 136' until a desired amount of
fabric material has been accumulated. The take-up roller can then
be removed from the machine and replaced with another take-up
roller to continue the process. If desired, the combined warp and
weft yarn material formed on either of the XD apparatus described
above can be reused as a substrate material. An adhesive material
would be required for further processing with additional layers of
weft yarn materials, but composite structures can be formed using
the apparatus described herein.
Pressure Lamination Apparatus and Nonwoven Fabrics Formed
Thereby
[0196] If desired, the bond between the warp yarns and weft yarns
can be made more intimate, for example by heating and cooling the
product under pressure, e.g., by a lamination apparatus. One
embodiment of a flat bed laminator 74 as illustrated in FIG. 1B,
may be positioned between the drive roller 133 and the take-up
roller 136. The flat bed laminator may be of a conventional type
manufactured by Reliant of Great Britain and serves to further
enhance the above described heating and cooling stations 68 and 70
respectively. The flat bed laminator reheats and then cools the
nonwoven fabric 131 to set the adhesive in a flat as opposed to
cylindrical configuration which is sometimes advantageous depending
upon the type of yarns utilized and further enhances the bond as
well.
[0197] A diagrammatic representation of a flat bed laminator of the
type that might be employed in the apparatus of the present
invention is shown in FIG. 1B. It will there be appreciated that
the laminator is disposed at the downstream end of the apparatus in
a position to receive the laminated fabric material 131 of the
present invention. The laminator includes a housing 288 in which
are disposed a pair of driven pressure belts 290 between which the
laminate passes and is driven through a heating/cooling system 292
with a first segment of the system comprising a heater 294 with
conventional heating coils or the like above and below the fabric
and the second segment of the system being a cooler 296 with
conventional cooling lines above and below the fabric. Accordingly,
as the fabric passes through the heating/cooling system the
adhesive is initially reactivated or remelted with the laminate in
a flat orientation and shortly thereafter the laminate is cooled to
thereby set the adhesive. Pressure is applied to the laminate by
the pressure belts 290 as it advances through the heating/cooling
system from above and below the laminate so that the cross-section
of the laminate changes from the arrangement illustrated in FIG. 41
where the weft yarns are lightly bonded to the warp yarns to an
orientation as shown in FIG. 42 where the weft yarns are further
embedded in the adhesive and, therefore, more tightly adhered to
the warp yarns.
[0198] After leaving the cooler 296, the fabric passes around the
end of the lower pressure belt 290 and then is directed upstream
through a pair of idler rollers 300 and onto the take-up roll 136
at the downstream end of the manufacturing apparatus.
[0199] An especially preferred high pressure lamination apparatus
400 is illustrated in FIGS. 71 through 77. The laminator 400
comprises a housing or frame in which a pressure box is mounted.
The pressure box comprises two spaced apart pressure sections, an
upper section and a lower section, wherein the space formed between
the two pressure sections defines the lamination section. Two
counter rotating drive belts, an upper drive belt and a lower drive
belt, are rotatably mounted in the housing or frame, and the belts
contact one another and are pulled through the lamination section
by drive rollers mounted at the outlet end. A pressure generator is
used to supplying air (or other fluid medium-liquid or gas)
pressure to the upper and lower sections of the pressure box for
compressing substrate materials carried between the two drive
belts. Pressure is maintained because the box has pressure seals
all around the points of contact with the belt. In the rectangular
box of the current preferred embodiment, side seals are provided on
the sides of both the upper and lower sections of the pressure box.
Inlet and outlet seals are also provided on the upper and lower
sections of the pressure box, ensuring that the desired diaphragm
effect can be created therein. When pressurized, the apparatus
caused the pressure lamination of substrates situated between the
two belts.
[0200] Referring to FIG. 71, a number of the essential components
of the preferred pressure box 401 used in the pressure laminator of
the present invention are shown in cross-section. As illustrated,
two rotatable belts, top belt 402 and bottom belt 404, mounted on a
plurality of support rollers (top--410, 420, 430; bottom--510, 520,
530), are pulled through the pressure box 401, between the upper
section 412 and the lower section 414, entering at the inlet end
416 and exiting at the outlet end 418, by their respective drive
rollers 550 (top) and 650 (bottom).
[0201] Alignment of the two rotating belts 402 and 404, is
maintained by an electric alignment system comprising an alignment
carriage 700, alignment pivot 710, electric alignment servo 720 and
electric alignment eye 730. If either of the belts move out of
alignment, the electric eye 730 detects the same and activates the
alignment servo, which causes the belt to be adjusted as necessary
by lateral movement of the alignment carriage 700.
[0202] Eight spaced apart radiant heat bars (310A, 310B, 310C, 310D
. . . 310H) are shown at the inlet end 416 of pressure box 401 and
eight spaced apart cooling bars (320A, 320B, 320C, 320D . . . 320H)
are shown at the outlet end 418 of pressure box 401. Four of the
heat bars are rigidly mounted in the lower section 414 of the
pressure box 401, namely heat bars 310A, 310C, 310E and 310G. The
other four radiant heat bars (310B, 310D, 310F and 310H) are
flexibly mounted such that they float above the upper belt,
permitting materials of varied thickness to pass there under. Four
of the cooling bars are rigidly mounted in the lower section 414 of
the pressure box 401, namely cooling bars 320A, 320C, 320E and
320G. The other four cooling bars (320B, 320D, 320F and 320H) are
flexibly mounted such that they float above the upper belt,
permitting materials of varied thickness to pass there under.
[0203] As illustrated, the plurality of heating and cooling bars
are preferably arranged in a staggered configuration. Thus, the
substrate is heated from below, then above, then below, etc., and
the cooling is accomplished in the same manner; the substrate is
cooled from below, then above, then below, etc. This arrangement
permits rapid and uniform heating, as well as rapid and uniform
cooling of the substrate materials being laminated in the pressure
laminator. The uniformity of heating and cooling under pressure
leads to improved physical characteristics of the resulting
laminates. In the case of nonwoven fabrics laminated in this
manner, shrinkage of the fabrics is held to a minimum and the
resulting laminated material has the appearance and feel of a woven
fabric.
[0204] In the preferred embodiment, at least 75 percent of the belt
width is heated and cooled by these elements. For example, on a 29
inch wide belt, the central 22 inches are heated and cooled. On a
76 inch wide belt, the central 60 inches would be heated and
cooled. The Reliant ERI 77A heat bars (England) are each provided
with a thermocouple to measure the temperature delivered to the
belts. The cooling bars are each provided with water fed cooling
pipes.
[0205] The thickness of the PTFE impregnated fiberglass belt can be
modified as desired, and depends on the nature of the materials
being laminated and the desired operating speed in feet per minute
(fpm). For laminating nonwoven fabrics, a belt thickness ranging
from 2 to 20 mil, preferably 5 to 15 mil has been found
satisfactory. Belts of 14 mil thickness have been operated at 5
fpm, with a temperature of 380.degree. F. being delivered to the
substrates. Belts of 5 mil thickness have been operated at 12 fpm,
with a temperature of 380.degree. F. being delivered to the
substrates. Optimum belt speeds of 50, 60, 70 . . . 100 fpm can be
achieved by modification of the belt thickness and/or composition.
The optimum belt speed for nonwoven fabric lamination is currently
believed to be 60-70 fpm. Another way in which to achieve higher
speeds is to simply increase the size of the laminator apparatus.
The current preferred apparatus has a length of about 4 feet.
Increasing the size from 2 times to 10 times would allow for faster
operating speeds.
[0206] During the lamination process the substrate material may
create a counter-pressure as any entrapped air in the substrates
expands. To deal with this counter-pressure, at lease one (or both)
of the PTFE (Teflon.RTM.) impregnated fiberglass drive belts used
in the pressure laminator of the present invention can be modified
on the outside edges, to comprise a thick (about 0.125 inch) porous
glass fiber mat (not shown). This porous glass fiber mat allows the
expanded air from the heated laminate to escape via this sideways
(transverse) porosity.
[0207] FIG. 72 illustrates in cross-section, one view of pressure
box 1, showing in particular the air pressure feed line 600, and
the preferred points of contact thereof 602 and 604 with the upper
section 412 and lower section 414 of the pressure box,
respectively. The pressure box is advantageously made out of metal,
such as aluminum (from 2 to 5 inches thick) and is held together by
a plurality of threaded steel rods and nuts 606 and 608. As shown
in FIG. 72, the heating and cooling bars located in the lower
section 414 of the pressure box are locked in place at each end by
a fixed bracket 610. The heating an cooling bars located in the
upper section 412 of the pressure box ride on a pin bracket mount
612, which allows upward motion of the bars, while gravity keeps
the bars resting on the upper belt. A plurality of cooling water
lines, inlet 614 and outlet 616 are also shown in this
illustration. The electrical heating wires (not shown) are provided
in a manner similar to the water lines.
[0208] FIG. 73 illustrates a top view of the interior of the upper
section 412 of the pressure box 401, showing the currently
preferred arrangement of the upper heating bars (310B, 310D, 310F
and 310H) and cooling bars (320B, 320D, 320F and 320H). The
pressurized box 401 is held together by steel bars 700 mounted to
the threaded rods 706 shown in the four corners. Not shown in this
illustration are the nuts that thread thereon. The sides 402 of the
housing or frame, to which the steel bars and all rollers and
controls are mounted, are also shown in this figure.
[0209] FIG. 74 illustrates, the pin bracket 812 for the upper
section, vertically displaceable, heating and cooling bars. As
illustrated, the pin bracket comprises a steel mounting bracket
800, fixed at one end to the aluminum side wall of the upper
section 412 of the pressure box. A slot (not shown) is provided
near the opposite end of bracket 800, through which a post 810
rides. The post 810 is mounted to the top of the heating or cooling
bar at one end and capped at the opposite end 812, thereby limiting
the vertical displacement distance of the heating and cooling bars.
The bracket for the lower section heating and cooling bars 820 is
also a steel bracket, but it is rigidly attached to both the
heating and cooling bars and the aluminum side wall of the lower
section 414 of the pressure box.
[0210] A suitable inlet and side pressure seal 850 is illustrated
in FIG. 74 and illustrated in greater detail in FIG. 75. This seal
is formed from a high temper curved aluminum slat 700
(0.008.times.13/8'') sandwiched between 2 mil PTFE (Teflon.RTM.)
tape 710 on the upper side and 10 mil ultrahigh molecular weight
polyethylene tape 720 on the bottom side. The seal is held in place
by a steel bracket 870.
[0211] As illustrated in FIGS. 76 and 77, it has been discovered
that the aluminum pressure seal taught in FIG. 74 can be
simplified, such that the side and inlet pressure seals consist
predominantly of the curved aluminum slat 700 as previously
described. The ultrahigh molecular weight polyethylene tape can be
omitted and the PTFE tape can be omitted, except in the corners 770
of the pressure box, where the tapes still prove useful. This
improved side seal and inlet pressure seal is best illustrated in
FIG. 76.
[0212] The inlet and outlet pressure seals are best illustrated in
FIG. 76. In addition to the curved aluminum slat 700, the belt side
of the aluminum slat is coated with 5 mil PTFE (Teflon.RTM.)
fiberglass cloth 900, which extends beyond the end of the aluminum
seal and mounts to the inside of the pressure box frame. This exit
seal design keeps the drive belt from binding on the aluminum
slat.
[0213] In use, the combined composite fabric material formed by the
XD apparatus, which has adhesive between a layer of aligned warp
yarns on one side and a layer of weft yarns substantially
perpendicular to the warp yarns on the other side, is fed to the
pressure laminator, either directly (as with the flat bed laminator
described above), or by a feed roll. The composite material is
drawn into the pressure box by the drive belts, through the inlet
seal and into the pressurized heating zone. The heating zone melts
the adhesive between the fabric layers and causes the adhesive
bridges to flow and spread between the layers of fabric. The
pressure holds the fabric in place, preventing shrinkage, and the
cooling zone, which has the same pressure as the heating zone,
cools the melted adhesive and fixes the bond between the layers of
fabric. This nonwoven fabric material has very high strength
characteristics and antifray characteristics, and represents yet
another especially preferred embodiment of the present
invention.
[0214] It will be appreciated that one or all of the
above-described nonwoven embodiments could be run through one of
the adhesive application stations a second time so that adhesive
would be applied to the laminate and then the adhesive covered
laminate secured to the warp yarns or other substrate to form a new
warp yarn material that has the laminate secured thereto for
passage through the nonwoven apparatus again so that a multiple
layer laminate of warp and weft yarns could be laid down. It is
also within the realm of this invention to include multiple weft
application stations spinning in the same direction or in opposite
directions to create various weft yarn angles of lay down. Yet
another potential embodiment is to laminate films on the front or
back of the nonwoven product of the invention for structural or
performance reasons. Alternatively, a film could also be positioned
between the warp and the weft yarns so that the yarns would then
provide structural support to the film.
[0215] A key feature of the nonwoven apparatus of the present
invention is that it provides a method of engineering a nonwoven
article. The weft yarns can have different properties, the warp
yarns can have different properties, the distance between warp
yarns and the distance between weft yarns can be adjusted, the
amount and type of adhesive can be adjusted, the angle of the weft
yarns relative to the warp yarns can be adjusted and the multiple
weft application and warp supply stations can be used to create a
multitude of different structures very efficiently and at high
speed. As a result of the above, the nonwoven product can also have
the same or different strengths in its warp and weft
directions.
[0216] Although the present invention has been described with a
certain degree of particularity, it is understood that the present
disclosure has been made by way of example, and changes in detail
or structure may be made without departing from the spirit of the
invention as defined in the appended claims.
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