U.S. patent application number 11/540054 was filed with the patent office on 2007-02-01 for process for creating fabrics with branched fibrils.
Invention is credited to Franklin Sadler III Love, Kasey R. Myers, Kirkland W. Vogt.
Application Number | 20070022587 11/540054 |
Document ID | / |
Family ID | 36264036 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070022587 |
Kind Code |
A1 |
Myers; Kasey R. ; et
al. |
February 1, 2007 |
Process for creating fabrics with branched fibrils
Abstract
The present process involves applying a plasticizer- or
solvent-containing solution to a subject fabric, preferably under
heated conditions, and then mechanically abrading the treated
fabric. The process results in the rearrangement of the fabric
structure, as a plurality of branched fibrils are created along the
length of the yarn filaments. Thus, the molecular weight of the
fabric's yarns and, therefore, the strength of the polymer chains
are maintained. Fabrics made from this process, which exhibit a
silk-like hand that results from the presence of multiple integral
fibrils and branched fibrils, are also provided.
Inventors: |
Myers; Kasey R.;
(Spartanburg, SC) ; Love; Franklin Sadler III;
(Columbus, NC) ; Vogt; Kirkland W.; (Simpsonville,
SC) |
Correspondence
Address: |
Legal Department (M-495)
P.O. Box 1926
Spartanburg
SC
29304
US
|
Family ID: |
36264036 |
Appl. No.: |
11/540054 |
Filed: |
September 29, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11040211 |
Jan 21, 2005 |
|
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11540054 |
Sep 29, 2006 |
|
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Current U.S.
Class: |
28/167 ;
428/91 |
Current CPC
Class: |
Y10T 442/10 20150401;
Y10T 442/30 20150401; D06C 11/00 20130101; Y10T 428/2978 20150115;
Y10T 428/2973 20150115; Y10T 428/2395 20150401; Y10T 428/2976
20150115 |
Class at
Publication: |
028/167 ;
428/091 |
International
Class: |
D06C 11/00 20060101
D06C011/00; D06C 29/00 20060101 D06C029/00 |
Claims
1. A process for creating a fibrillated fabric, said fabric
comprising a plurality of continuous filament yarns, said process
comprising the steps of: (a) providing a fabric; (b) applying a
fiber-specific chemical agent to said fabric, said fiber-specific
chemical agent comprising a plasticizer or solvent-containing
solution; and (c) abrading said fabric to which the fiber-specific
chemical agent has been applied, such that at least some of said
continuous filament yarns of said fabric have fibers from which
multiple integral fibrils and multiple branched fibrils protrude,
thereby imparting in said fabric a silk-like hand.
2. The process of claim 1 wherein said fabric is selected from the
group consisting of woven fabrics, knit fabrics, nonwoven fabrics,
braided fabrics, pile fabrics, scrims, and composites containing at
least one of these fabrics.
3. The process of claim 2 wherein said fabric is a woven
fabric.
4. The process of claim 2 wherein said fabric is a knit fabric.
5. The process of claim 1 wherein said continuous filament yarns
are selected from the group consisting of polyesters, polyamides,
polypropylenes, olefins, polyolefins, polyurethanes, aramids,
acrylics, modacrylics, blends of any of these fibers with one or
more other fibers, and blends of any of these fiber types with
natural fibers.
6. The process of claim 5 wherein said yarns are polyester.
7. The process of claim 6 wherein said fiber-specific chemical
agent is a plasticizer selected from the group consisting of
phenolic compounds, chlorinated aromatic compounds, aromatic
hydrocarbons and ethers, aromatic esters, and phthalates.
8. The process of claim 7 wherein said plasticizer is present in an
amount of between about 0.1% to about 10% of the weight of an
aqueous solution into which said fabric is immersed in step
(b).
9. The process of claim 6 wherein said fiber-specific chemical
agent is a solvent selected from the group consisting of
n-methyl-2-pyrrolidone, propylene glycol n-butyl ether, propylene
glycol n-phenyl ether, dipropylene glycol methyl ether, di-basic
esters, and imidazole-containing solvents.
10. The process of claim 1 wherein said fabric to which the
fiber-specific chemical agent has been applied is heated between
step (b) and step (c).
11. The process of claim 1 wherein said fabric to which the
fiber-specific chemical agent has been applied is heated
simultaneous with step (c).
12. The process of claim 10 wherein said fabric is heated to
temperatures of between 40.degree. C. and 100.degree. C.
13. The process of claim 1 wherein said abrading is accomplished by
a technique selected from the group consisting of needling;
napping; napping with diamond-coated napping wire; gritless
sanding; patterned sanding against an embossed surface;
shot-peening; sand-blasting; particle bombardment; ice-blasting;
tumbling; brushing; impregnated brush rolls; ultrasonic agitation;
stone-washing; sueding; engraved roll abrasion; patterned roll
abrasion; constricting through a jet orifice; and impacting against
or with another material, said other material being selected from
the group consisting of the same fabric, a different fabric,
abrasive substrates, steel wool, diamond grit rolls, tungsten
carbide rolls, etched rolls, scarred rolls, and sandpaper
rolls.
14. The process of claim 13 wherein said abrading is accomplished
by impacting said fabric against or with another material.
15. The process of claim 1 wherein said fabric is dyed after step
(c).
16. The process of claim 1 wherein said fabric is printed after
step (c).
17-25. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a process for creating
fine-scale multiple fibrils and branched fibrils that are
integrally connected to the filaments from which they protrude. The
process involves mechanically abrading, preferably under heated
conditions, a fabric to which a plasticizer- or solvent-containing
solution has been applied. The fabric containing such a fibrillated
structure is also disclosed.
BACKGROUND
[0002] All patents described herein are hereby incorporated by
reference.
[0003] There have been numerous attempts to modify synthetic
fabrics (particularly polyester) to improve their hand and/or
appearance. Conventionally, sanding or napping of the fabric has
been used to soften the hand and, in the case of continuous
filament polyester fabric, to deluster the fabric. Sanding alone,
however, typically results in large numbers of broken yarn ends, in
which the broken ends have substantially the same diameter as the
originating yarns, thereby yielding a fabric with a somewhat harsh
hand and whitened and blurred surface.
[0004] Efforts to modify the surface of synthetic-containing fabric
with specialized finishing equipment have also been used with some
degree of success. Various abrading mechanisms have been employed,
including abrasion with sandpaper, diamond grit, and the like, as
described in U.S. Pat. No. 5,058,329 and U.S. Pat. No. 5,109,630,
both to Love et al.; U.S. Pat. No. 5,815,896 to Dischler; and U.S.
Pat. No. 5,819,816 to Dischler. Further, subject fabrics have also
been modified by treatment with high-pressure streams of air or
water, as described in U.S. Pat. No. 4,918,795 to Dischler; U.S.
Pat. No. 5,033,143 to Love, III; and U.S. Pat. No. 6,546,605 to
Emery et al. The success of these efforts has been largely
dependent on the starting fabric and the desired results. However,
these approaches failed to create the multiple and branched
fibrillated structure that is characteristic of the present process
and product.
[0005] Others have attempted to create fibrillated, scale-like
textile structures through the use of chemical application combined
with face-finishing techniques. U.S. Pat. Nos. 4,421,513 and
4,331,724 to Su describe a process for fibrillating polyester
materials, which involves lowering the molecular weight of the
polyester, treating it with a 100% concentrated swelling agent, and
abrading the fabric. The result of this process is a fabric that
has scale-like fibrils projecting away from the convex portion of
the filament curvature (that is, the fibrils are produced only on
one side of the fabric at places along the filament that are
exposed to abrasion). The fabric is also weakened because of the
process used to reduce the molecular weight of the polyester. These
references do not contemplate a dual-sided treatment of the fabric
or a method to enhance fibrillation to create multiple fibrils and
fibrils with multiple splitting.
[0006] An apparatus and process are described in U.S. Pat. Nos.
5,058,329 and 5,109,630 to Love et al. to implement the art
described in the Su patents. The process abrades fabric against a
roll covered with rounded tungsten-carbide particles, after
saturating the fabric with 100% methylene chloride at room
temperature. The teachings of Love et al. fail to disclose a fabric
having multiple fibrils and branched fibrils that are integrally
connected to the filaments from which they protrude.
[0007] Yet another method of modifying fabrics is described in U.S.
Pat. No. 4,259,393 to Marco. Marco teaches treating a fabric
containing texturized polyester filaments with an alkaline solution
in a jet-dyeing machine in order to chemically break a substantial
number of the filaments. When the fibers break, the broken ends
split into multiple filaments as a result of their exposure to the
alkaline solution at preferred temperatures of between 45.degree.
C. and 55.degree. C. Marco suggests that smaller filaments should
project from each broken end. Like the Su and Love et al.
references discussed above, Marco does not present a method for
creating the multiple fibrils or branched fibrils that are
characteristic of the present product.
SUMMARY
[0008] The present process involves applying a plasticizer- or
solvent-containing solution to a subject fabric, preferably under
heated conditions, and then mechanically abrading the treated
fabric. The process results in the rearrangement of the fabric
structure, as a plurality of branched fibrils are created along the
length of the yarn filaments. Thus, the molecular weight of the
fabric's yarns and, therefore, the strength of the polymer chains
are maintained.
[0009] Benefits of the present process and product include, in one
preferred embodiment, the use of relatively inexpensive yarns made
entirely of single-component polymers (as opposed to the use of
multi-component filaments that are commonly described as being
easily splittable or "island-in-the-sea"-type filaments). Fabrics
made from the present process retain their surface sharpness or
clarify, making it possible to create fibrillated fabrics with
fine-gauge stylized appearances. Further, fabrics made from this
process exhibit a silk-like hand that results from the presence of
multiple integral fibrils and branched fibrils. In fact, the
process achieves a microdenier-like soft hand without the
limitations of using microdenier fibers, which include poor
abrasion resistance, difficulty in and a relatively higher expense
of dyeing, and poor lightfastness.
DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a flow-chart of the process of making a
fibrillated fabric; and
[0011] FIGS. 2 through 6 are photomicrographs of fibrillated
fabrics of the present disclosure, taken with an AMRAY scanning
electron microscope, Model 1845 FE (1991).
DETAILED DESCRIPTION
[0012] As used herein, "fiber" is defined as a unit of matter,
either natural or manufactured, that forms the basic element of
fabrics and other textile structures. A fiber is characterized by
having a length at least 100 times its diameter or width.
[0013] "Fibrillation" is defined as the act or process of forming
fibrils, such as by breaking up a fiber into the minute fibrous
elements from which the main structure is formed.
[0014] "Fibril" is defined as a tiny, threadlike element of a
natural or synthetic fiber that is still integrally attached to its
parent filament at one or both ends. A "branched fibril" is a
threadlike element of a natural or synthetic fiber that is split
into multiple smaller elements, all of the smaller elements
originating from and being integrally attached to the parent
filament.
[0015] Fibrillation results in a fabric with finer filaments, as a
plurality of fibrils is formed from a portion of the filaments that
is moved away from the main body of the filaments. Thus,
fibrillation is not an additive or subtractive process, but rather
a fiber rearrangement process. The advantage of this approach is
that the fabric's overall weight is essentially unchanged.
[0016] Turning now to the drawings, FIG. 1 provides a flowchart of
the preferred present process for creating integral, branched
fibrils on a subject fabric. Step 10 is to provide a fabric for
modification. Fabrics contemplated for use with the present process
include woven fabrics, knit fabrics, nonwoven fabrics, braided
fabrics, pile fabrics, scrims, composites, spacer fabrics, and
other fabric constructions as may be conventionally processed
through a sander.
[0017] The fabrics may be made of yarns containing fiber types such
as polyesters, polyamides, polypropylenes, olefins and polyolefins,
polyurethanes, aramids (such as Kevlar), acrylics, modacrylics,
blends of any of these fibers with one or more other fibers, and
blends of any of these fiber types with natural fibers (such as
cotton). The presence of natural fibers will not inhibit the
effects of the present process on the synthetic components of the
fabric and may enhance certain characteristics of the natural
fibers (e.g., hand). Preferably, the yarns are continuous filament
yarns, although the process may be applied to spun yarns as well.
Most preferably, the yarns are polyester.
[0018] Before being subjected to the present process, the fabric
may be dyed; calendered; embossed; coated; sheared; screen
patterned; digitally patterned by hot air, water, lasers, or the
like; combined into a composite; or printed. In one embodiment as
will be discussed herein, the fabric is in its greige state when
processed.
[0019] Step 20 involves the application of a chemical agent
(specifically, a fiber-specific plasticizer- or solvent-containing
solution) to the fabric. Suitable application techniques include
dipping, spraying, foam coating, and other methods that may be
known to those of skill in the art. Preferably, the plasticizer or
solvent is part of an aqueous solution. Suitable amounts of
plasticizing agent range from about 0.1% to about 100% of the
weight of the solution and, preferably, are from about 0.1% to
about 10% of the weight of the solution.
[0020] Alternatively, step 20 can be accomplished in a batch-dyeing
process (including jet-dyeing, beck dyeing, and the like), in which
the fabric is placed in a pressurized vessel and baths are
exhausted onto the fabric. In this environment, the fabric is
typically agitated in a rope form. Calculations of the amount of
necessary fiber-specific plasticizer or solvent would be based on
the weight of the fabric, rather than the weight of the solution.
Preferably, when using a jet-dye machine, the plasticizing agent or
solvent should be present in an amount of between about 0.1% to
about 10% of the weight of the fabric.
[0021] Preferred plasticizers for polyester include phenolic
compounds (such as o-phenylphenol, p-phenylphenol, and methyl
cresotinate), chlorinated aromatic compounds (such as
o-dichlorobenzene and 1,3,5-trichlorobenzene), aromatic
hydrocarbons and ethers (such as biphenyl, methylbiphenyl, diphenyl
oxide, 1-methylnapthalene, 2-methylnaphthalene), aromatic esters
(such as methyl benzoate, butyl benzoate, benzyl benzoate, and
ethyl hexyl benzoate), and phthalates (such as dimethyl phthalate,
diethyl phthalate, diallyl phthalate, and dimethyl terephthalate).
Of these plasticizers for use with polyester fibers, ethyl hexyl
benzoate is preferred at amounts from about 0.1% to about 10% of
the weight of the solution.
[0022] Alternatively, certain solvents in which the fiber type may
be at least slightly soluble may be used in place of the
plasticizer. Examples of such solvents for use with polyester
include n-methyl-2-pyrrolidone, propylene glycol n-butyl ether,
propylene glycol n-phenyl ether, dipropylene glycol methyl ether,
di-basic esters, and imidazole-containing solvents.
[0023] Solvents useful for other fiber types are documented in
Handbook of Polymer-Liquid Interaction Parameters and Solubility
Parameters by Allan F. M. Barton (published 1990). By way of
example only and not limitation, solvents suitable for use with
polyamides include trifluoroethanol, trichloroethanol, phenol,
cresols, halogenated acetic acids, and sulfuric acid. Examples of
solvents suitable for use with polypropylenes include n-hexane,
1-propanol, 1-butanol, methylcyclohexane, and
tetrachloromethane.
[0024] One advantage of the present approach, when using
plasticizer-containing solutions, is a decrease in the amount of
chemical agent that is used to modify the fabric (for example, as
compared with solvent-based systems). A further benefit is that the
plasticizer- and solvent-containing solutions contemplated for use
herein are relatively easy and safe to use in large-scale
manufacturing. Yet another benefit of using plasticizer-containing
solutions is that it provides a vehicle for the fibrillation of the
fabric's fibers without the destruction of the fibers (that is, the
fabric's structure is rearranged without significant weight or
strength loss).
[0025] Step 30 is the optional application of heat to the fabric to
which the plasticizer-containing solution has been added. Step 30
can be accomplished either simultaneously with the application of
the plasticizer-containing solution or subsequent to the
application of the plasticizer-containing solution. It has been
found that having the plasticizer-treated fabric hot can accelerate
and enhance the fibrillation process, but it is not required. To
achieve maximum productivity, temperatures at the site of abrasion
in the range of 40.degree. C. to 100.degree. C. are preferred,
depending on the fiber type and plasticizing agent being used.
[0026] Step 40 is the mechanical abrasion of the fabric.
Preferably, the fabric is mechanically abraded on both sides,
although one-sided abrasion is also possible. The fabric can be
abraded using techniques such as needling; napping; napping with
diamond-coated napping wire; gritless sanding; patterned sanding
against an embossed surface; shot-peening; sand-blasting; particle
bombardment; ice-blasting; tumbling; brushing; impregnated brush
rolls; ultrasonic agitation; stone-washing; sueding; engraved or
patterned roll abrasion; constricting through a jet orifice;
impacting against or with another material, such as the same or a
different fabric, abrasive substrates, steel wool, diamond grit
rolls, tungsten carbide rolls, etched or scarred rolls, or
sandpaper rolls; and the like. The preferred abrading technique is
described in U.S. Pat. No. 5,819,816 to Dischler, in which the
fabric is abraded against a plurality of diamond-grit rolls,
allowing fabric-abrading speeds of up to 200 yards per minute. The
mechanical abrasion of a fabric treated with a fiber-specific
plasticizer results in a fabric whose filaments contain a plurality
of integral, branched fibrils.
[0027] Steps 50 through 80 are optional steps. Step 50 involves
washing the fabric to remove any remaining plasticizer. Step 60
involves dyeing the fabric to a desired shade. Step 60 may also
occur before Step 20, for instance, in cases where the fabric is
dyed before being treated or where the fabric is made from pre-dyed
yarns. Step 70 involves drying the fabric. Step 80 involves
printing the fabric, if so desired. Step 80 may also occur before
Step 20, for instance, as with the dyeing step.
[0028] The following Examples are representative of the present
process and product.
EXAMPLE 1
[0029] A sample of woven 100% polyester continuous filament fabric
was placed in a tensioning device, which applied about 12 pounds of
tension per linear inch in the warp direction of the fabric. The
tensioning device held the fabric close to a surface heated to
about 125.degree. C. A chemical treatment of 100%
1-methyl-imidazole was applied to the fabric until saturated.
Immediately thereafter, an orbital abrasion device (having a piece
of the untreated fabric as an abrasive) was pressed against the
saturated fabric at a pressure of about 2 pounds per square inch,
abrading the saturated fabric for a period of about 3 minutes. The
sample was then removed from the heated surface and rinsed. The
fabric was examined using a scanning electron microscope, as shown
in FIG. 2.
[0030] FIG. 2 is a photomicrograph at a 125.times. level of
magnification of a plain-woven continuous filament polyester
fabric, which illustrates the fibrillation that is characteristic
of the present product. The photomicrograph shows a plurality of
abraded fibrils that extend from and are integral to the
originating filaments. The fibrils, which are randomly oriented
with respect to the filaments from which they originated, are
present in the warp and fill direction of the fabric. FIG. 2 also
illustrates that the fibrils can possess a very high aspect
ratio.
EXAMPLE 2
[0031] A sample of woven 100% polyester continuous filament fabric
was placed in a tensioning device, which applied about 12 pounds of
tension per linear inch in the warp direction of the fabric. The
tensioning device held the fabric close to a surface heated to
about 125.degree. C. A chemical treatment of 100% polyethylene
glycol methyl ether (molecular weight=750) was applied to the
fabric until saturated. Immediately thereafter, an orbital abrasion
device (having a piece of the untreated fabric as an abrasive) was
pressed against the saturated fabric at a pressure of about 2
pounds per square inch, abrading the saturated fabric for a period
of about 3 minutes. The sample was then removed from the heated
surface and rinsed. The fabric was examined using a scanning
electron microscope, as shown in FIG. 3.
[0032] FIG. 3 is a photomicrograph at a 500.times. level of
magnification of a plain-woven continuous filament polyester
fabric, which illustrates the fibrillation that is characteristic
of the present product. The photomicrograph shows considerable
branched fibrillation of a broken filament in the fabric and
overall fibrillation of the unbroken filaments. The breaking of
filaments is a potential side effect of the present process that is
deleterious to the overall strength of the fabric, but which may
further modify the fabric hand.
EXAMPLE 3
[0033] A sample of woven 100% polyester continuous filament fabric
was immersed for thirty minutes in an aqueous chemical solution,
brought to a rolling boil, including methyl benzoate at 9.5% of the
weight of the solution and surfactants at 0.5% of the weight of the
solution. The fabric was then placed in a tensioning device, which
applied about 12 pounds of tension per linear inch in the warp
direction of the fabric. The tensioning device was positioned over
and held the fabric close to a porous steam vessel where steam was
allowed to percolate through the fabric to reach a temperature
approaching about 100.degree. C. Immediately thereafter, an orbital
abrasion device (having a piece of the untreated fabric as an
abrasive) was pressed against the saturated fabric at a pressure of
about 2 pounds per square inch, abrading the saturated fabric for a
period of about 3 minutes. The sample was then removed from the
heated surface and rinsed. The fabric was examined using a scanning
electron microscope, as shown in FIG. 4.
[0034] FIG. 4 is a photomicrograph at a 500.times. level of
magnification of a woven continuous filament polyester fabric,
which illustrates the fibrillation that is characteristic of the
present product and which further illustrates the intended effect
of high aspect ratio fibrils that extend from parent filaments that
are unbroken.
EXAMPLE 4
[0035] An aqueous bath was created containing 3% vinylimidazole and
3% butyl benzoate-based plasticizer, both based on the weight of
the solution. A 2-inch wide sample of woven 100% solution dyed
polyester fabric having texturized continuous filaments was
subjected to a continuous dip through the aqueous bath and over a
system of rolls. The fabric was abraded by threading the fabric
through the rolls such that the fabric rubbed against itself under
tension and in opposing directions over a two-inch long zone of
abrasion. The aqueous bath was recirculated to maintain a
temperature of between 60.degree. C. and 80.degree. C. The pressure
used to tension the fabric was about 40 pounds per linear inch in
the warp direction. The fabric was subjected to 120 cycles of
abrasion. The fabric was examined using a scanning electron
microscope, as shown in FIG. 5.
[0036] FIG. 5 is a photomicrograph at a 250.times. level of
magnification of a woven continuous filament polyester fabric,
which shows the presence of fibrillation on texturized polyester
fibers that resulted from the process described above.
EXAMPLE 5
[0037] An aqueous bath was created containing 0.5% ethyl hexyl
benzoate-based plasticizer, which was heated in a dip pan by a
steam jacket to maintain a temperature of about 70.degree. C. A
sample of a jacquard woven 100% polyester continuous filament
fabric having solution dyed yarns was passed through the aqueous
bath and subsequently squeezed through nip rolls. The fabric was
incidentally cooled before being subjected to abrasion by a
plurality of diamond-grit rolls over which the fabric was threaded.
The diamond-grit rolls were not heated, although the addition of
heat to the abrasive rolls or the abrading environment may be
preferred in some embodiments. The fabric was taken up and rinsed.
The fabric was examined using a scanning electron microscope, as
shown in FIG. 6.
[0038] FIG. 6 is a photomicrograph at a 150.times. level of
magnification of a woven continuous filament polyester fabric,
which provides further evidence of branched fibrillation.
[0039] Thus, from the Examples, it can be appreciated that
fine-scale multiple and branched fibrillation structure results
from the use of the present process. Fabrics fibrillated according
to this approach may be useful as automotive fabrics, napery
fabrics, apparel fabrics, substrate fabrics, and for other end-uses
where a modified fabric surface is desired. By way of example only
and not limitation, the fabric can be fibrillated in its greige
state, dyed, and then combined with another material to make a
composite that is useful as automotive seat cushions.
* * * * *