U.S. patent application number 15/733466 was filed with the patent office on 2021-04-29 for slivers containing cellulose acetate for spun yarns.
This patent application is currently assigned to Eastman Chemical Company. The applicant listed for this patent is Eastman Chemical Company. Invention is credited to Kelmara Khadene Kelly, Evan V. Rodick, Chad C. Smith, Ronald A. Snell.
Application Number | 20210123166 15/733466 |
Document ID | / |
Family ID | 1000005339853 |
Filed Date | 2021-04-29 |
![](/patent/app/20210123166/US20210123166A1-20210429\US20210123166A1-2021042)
United States Patent
Application |
20210123166 |
Kind Code |
A1 |
Kelly; Kelmara Khadene ; et
al. |
April 29, 2021 |
SLIVERS CONTAINING CELLULOSE ACETATE FOR SPUN YARNS
Abstract
Sliver containing cellulose acetate staple fibres is obtained
that exhibits good fibre to fibre cohesion energy and can be
successfully drawn and made into spun yarns. Such slivers can be
made of cellulose acetate staple fibres that have of round shape, a
denier of less than 3.0, a crimp frequency per inch (CPI) from 5 to
30, a good fibre to fibre coefficient of friction and have a low
static charge. The textile fabrics made from spun yarns have
plant-based renewable resources by containing the cellulose acetate
staple fibres, and can exhibit a thermoplastic behaviour to impart
better dimensional stability to a textile fabric. The low denier of
the cellulose acetate fibres can impart a feel similar to that of
cotton, yet can be successfully processed through carding machines
to form cohesive slivers and retain their integrity throughout the
drawing process, allowing them to be formed into spun yarns.
Inventors: |
Kelly; Kelmara Khadene;
(Kingsport, TN) ; Rodick; Evan V.; (Kingsport,
TN) ; Smith; Chad C.; (Johnson City, TN) ;
Snell; Ronald A.; (Kingsport, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eastman Chemical Company |
Kingsport |
TN |
US |
|
|
Assignee: |
Eastman Chemical Company
Kingsport
TN
|
Family ID: |
1000005339853 |
Appl. No.: |
15/733466 |
Filed: |
February 26, 2019 |
PCT Filed: |
February 26, 2019 |
PCT NO: |
PCT/US19/19580 |
371 Date: |
August 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62635812 |
Feb 27, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D02G 3/02 20130101; D10B
2201/28 20130101; D02G 3/22 20130101 |
International
Class: |
D02G 3/02 20060101
D02G003/02; D02G 3/22 20060101 D02G003/22 |
Claims
1. A carded sliver comprising cellulose acetate staple fibers (CA
staple fibers) having a round shape, a denier of less than 3.0, a
crimp frequency per inch (CPI) from 5 to 30, and wherein said
sliver either: a. has a fiber-to-fiber cohesion energy of at least
10,000 Joules, or b. is obtained from CA staple fibers having a
scroop value of at least 0.2 and not more than 1.
2. The carded sliver of claim 1, wherein said CA staple fibers have
an uncrimped fiber to fiber coefficient of dynamic friction (F/F
CODF) between 0.11 to less than 0.2 as measured according to ASTM
D3412/3412M-13, at one twist, a rate of 20 m/min, and with an input
tension of 10 grams on filaments used to make said CA staple
fibers.
3. The carded sliver of claim 1, wherein said CA staple fibers have
a static electricity charge of less than 1.0 kV at 65% relative
humidity as measured using an electrostatic fieldmeter on a two
foot sample length of filaments used to make said CA staple fibers
rubbed with three times back and forth.
4. The carded sliver of claim 1, wherein the sliver has a
coefficient of variation (CVm) of no more than 4.5% or not more
than 4%.
5. The carded sliver of, claim 1 wherein the sliver has a short
fiber content (less than 1/2 inch) of no more than 15% as
determined by the Keisokki Fiber Length Distribution Tester.
6. The carded sliver of, claim 1 wherein at least 10 wt. % and up
to 55% of the staple fibers in the sliver are CA staple fibers, and
wherein the CA staple fibers are coated with a finish.
7. The carded sliver of, claim 1 wherein the CA staple fibers have
a denier from 0.5 to 1.9, a CPI from 8 to 19, and wherein the
cellulose acetate used to make the fibers has an acetyl degree of
substitution of at least 2.2.
8. The carded sliver of claim 1, wherein the CA staple fibers have
a CPI:DPF ratio from 6:1 to 14:1.
9. The carded sliver of any one of claim 1, wherein at least 90% of
the CA staple fibers have a shape factor from 1.0 to 1.5.
10. The carded sliver of claim 1, wherein at least 90 wt. % of the
CA staple fibers have a cut length of 10 mm to 150 mm.
11. The carded sliver of claim 1, wherein said CA staple fibers are
coated with a finish in an amount of less than 2.0 wt. % FOY on a
dry weight basis.
12. The carded sliver of claim 1, wherein said CA staple fibers
have a tenacity of at least 0.9 grams-force/denier, as measured
according to ASTM D3822, or are made from filaments that have a
tenacity of at least 0.9 grams-force/denier, as measured according
to ASTM D3822.
13. The carded sliver of claim 1, wherein said CA staple fibers
have an elongation at break of at least 15%, as measured according
to ASTM D3822, or wherein the sliver is obtained from staple fibers
made from filaments that have an elongation at break of at least
15%, as measured according to ASTM D3822.
14. The carded sliver of claim 1 having a fiber-to-fiber cohesion
energy of at least 15,000 Joules or at least 20,000 Joules.
15. A spun yarn obtained from one or more carded slivers that are
drawn, and at least one of said carded staple slivers comprising
cellulose acetate staple fibers (CA staple fibers) having a round
shape, a denier of less than 3.0, a crimp frequency per inch (CPI)
from 5 to 30 wherein said at least one sliver either: a. has a
fiber-to-fiber cohesion energy of at least 10,000 Joules, or b. is
obtained from CA staple fibers having a scroop value of at least
0.2 and not more than 1.
16. The spun yarn of claim 15, wherein said CA staple fibers have
an uncrimped fiber to fiber coefficient of dynamic friction (F/F
CODF) between 0.11 to less than 0.2 as measured by according to
ASTM D3412/3412M-13, at one twist, a rate of 20 m/min, and with an
input tension of 10 grams on filaments used to make said CA staple
fibers, and have a have a static electricity charge of less than
1.0 kV at 65% % relative humidity as measured on a two foot sample
length of filaments used to make said CA staple fibers rubbed with
three times back and forth.
17. The spun yarn of claim 1, wherein said yarn contains from 10
wt. % to 70 wt % CA staple fibers.
18. The spun yarn of claim 15, wherein said yarn has at least one
of the following characteristics: (i) a breaking force of at least
150 g-N, as measured according to ASTM D2256 on a sample containing
100% of the CA staple fibers, (ii) a tenacity of at least 0.85
gF/denier as measured according to ASTM D2256 on a sample
containing 100% of the CA staple fibers, or (iii) an elongation at
break of at least 13% as measured according to ASTM D2256 on a
sample containing 100% of the CA staple fibers.
19. The spun yarn of claim 1, having a total denier of less than
300 and a twist per inch of less than 4.
20. A textile fabric obtained from spun yarn, said yarn obtained
from carded slivers comprising CA staple fibers (CA staple fibers)
containing a quantity of spin finish, and wherein the textile
fabric contains no spin finish or a quantity of spin finish that is
less than said quantity on the CA staple fibers, said staple CA
staple fibers having round shape, a denier of less than 3.0, a
crimp frequency per inch (CPI) from 5 to 30, wherein said one or
more carded slivers either: a. has a fiber-to-fiber cohesion energy
of at least 10,000 Joules, or b. is obtained from CA staple fibers
having a scroop value of at least 0.2 and not more than 1.
21.-42. (canceled)
Description
FIELD OF THE INVENTION
[0001] This invention relates to slivers containing cellulose
acetate staple fibers to make rovings and spun yarns for textile
fabrics, and more particularly, to slivers having good
fiber-to-fiber cohesion energy.
BACKGROUND
[0002] Textile fabrics consisting of spun yarns are widely used in
a variety of applications. These fabrics are formed by weaving,
knitting, crocheting, knotting, or felting yarn made of natural
and/or synthetic materials, such as, for example, polyesters,
polyamides, acrylics, polyurethanes, glass, wool, polypropylene,
silk, cashmere, sisal, flax, hemp, cotton, a variety of regenerated
cellulosic materials, such as viscose, Modal, and Lyocell, and is
often formed as a blend of two or more of these materials.
[0003] While the use of regenerated cellulosic materials has the
advantage of originating from plant based renewable resources
(cellulose), they do no exhibit thermoplastic behavior. Typically,
textile fabrics containing regenerated cellulosic materials,
cottons, hemp or flax are blended with a heat settable material
such as a polyester or nylon which are thermoplastic to provide the
dimensional stability needed for a textile fabric, such as low
shrinkage, low twist, and low skew. Alternatively, textile fabrics
without such thermoplastic materials need to be resin treated
and/or pre-shrunk to impart dimensional stability. It would be
desirable to provide a textile fabric blend with a material that
originates from a plant based renewable resource and exhibits the
heat setting behavior of a thermoplastic material without the need
for resin treating and/or pre-shrinking.
[0004] Even if the material of choice meets end use performance
requirements, it is not likely to be adopted into a textile fabric
market if it cannot be processed on existing equipment used to make
spun yarn. A significant portion of the spun yarn market uses a
ring spinning process from rovings made from drawn slivers of
staple fibers obtained through a carding process. The staple fiber
should be suited to be carded into cohesive slivers that can be
ring spun into yarn, all using conventional and existing equipment.
Key to the success of such a material is its ability to be carded
successfully and drawn into slivers of adequate uniformity and
strength. The staple fibers used to make the slivers should be
capable of imparting a cohesiveness to the sliver to retain the
integrity and shape of the sliver, yet have a sufficiently low
dynamic coefficient of friction to allow the sliver to be easily
drafted.
[0005] The replacement material should also have a soft feel closer
to that of cotton rather than the synthetic feel of polyester,
polypropylene, or polyethylene fibers. Fibers having a low denier
are better suited to achieve a softer feel, however, low denier
fibers are more difficult to process. To separate and efficiently
orient the fibers in a carding operation, and to assist in
retaining the sliver integrity, a crimp is imparted to the fiber
which normally does not have a significant impact on the strength
of higher denier fibers. However, as the denier drops below 3, the
application of crimp can weaken the tenacity of the fiber to a
point where the fibers easily break, forming a dust like lint that
results in both fiber loss and frequent shut down of machinery to
clean out rapidly accumulating lint.
[0006] It would be desirable to utilize a replacement material for
regenerated cellulose that, as a material, originates from a plant
based renewable resource, has a thermoplastic behavior to impart
better dimensional stability to a textile fabric compared the same
textile fabric containing regenerated cellulose, has a low denier
to impart a feel similar to that of cotton, and with the right
combination of properties to be processed through carding machines
to form cohesive slivers and successfully formed into spun yarns.
In particular, slivers made from such CA staple fibers should have
good cohesive energy to enable their formation into carded slivers
and retain their integrity throughout the drawing processes.
SUMMARY OF THE INVENTION
[0007] There is now provided a carded sliver comprising CA staple
fibers having a round shape, a denier of less than 3.0, a crimp
frequency per inch (CPI) from 5 to 30, and wherein said sliver has
a fiber-to-fiber cohesion energy of at least 10,000 joules.
[0008] There is also provided a spun yarn obtained from one or more
carded slivers, at least one of said carded slivers comprising CA
staple fibers having a round shape, a denier of less than 3.0, a
crimp frequency per inch (CPI) from 5 to 30, and wherein said
sliver has a fiber-to-fiber cohesion energy of at least 10,000
Joules.
[0009] The invention also includes a textile fabric fabric obtained
from spun yarn, said yarn obtained from carded slivers comprising
CA staple fibers (CA staple fibers) containing a quantity of spin
finish, and wherein the textile fabric contains no spin finish or a
quantity of spin finish that is less than said quantity on the CA
staple fibers, said staple CA staple fibers having round shape, a
denier (DPF) of less than 3.0, a crimp frequency per inch (CPI)
from 5 to 30, wherein said one or more carded slivers has a
fiber-to-fiber cohesion energy of at least 10,000 joules.
[0010] Desirably, the CA staple fibers used to make the carded
sliver have an untwisted fiber to fiber coefficient of dynamic
friction (F/F CODF) between 0.11 to less than 0.2, as measured on
an uncrimped filament yarn by ASTM D3412/3412M-13 with uncrimped
filaments of the same composition, shape, and denier as said CA
staple fibers. The CA staple fibers used to make the carded sliver
also have a static electricity charge of less than 1.0 at 65%
relative humidity as determined on a filament yarn.
BRIEF DESCRIPTION OF THE FIGURES
[0011] FIG. 1 relates the different parameters used to determine
the crimp amplitude of a crimped fiber.
DETAILED DESCRIPTION
[0012] It has been found that slivers can be successfully formed
from CA staple fibers and further processed successfully to spun
yarns to make textile fabric. At the same time, the CA staple
fibers may be environmentally-friendly, exhibit thermoplastic
behavior, have a soft feel similar to that of cotton, and can be
processed using both new and existing processing equipment.
[0013] As used herein, textile fabrics are materials made from spun
yarn and that are either woven, knitted, crocheted, knotted,
embroidered, braided/plaited, laced, or carpet piling. Textile
fabrics include geotextile fabrics, carpet pilings, and fabrics
(which includes cloth). The geotextile fabrics as used in the
context of a textile fabric herein are those that are woven or
knitted. Examples of suitable types of textile fabrics formable
from the inventive staple fibers can include, but are not limited
to, clothing (undergarments, socks, hats, shirts, pants, dresses,
scarves, gloves, etc.), bags, baskets, upholstered furnishings,
window shades, towels, table cloths, bed coverings, flat surface
coverings, in art work, filters, flags, backpacks, tents,
handkerchiefs, rags, balloons, kites, sails, parachutes, automotive
upholstery, protective clothing such as against heat for
firefighters and welders, protective clothing for bullet armor or
stab protection, medical textile fabrics such as implants, and
agrotextile fabrics for crop protection. A CA staple fiber means a
cellulose acetate staple fiber, and a "staple fiber" refers to a
fiber cut from a continuous filament or tow band of continuous
filaments. A carded sliver, spun yarn, or textile fabric "obtained
from" a described element includes any number and type of
intervening steps or process operations.
[0014] There is now provided a carded sliver comprising CA staple
fibers having a round shape, a denier of less than 3.0, a crimp
frequency per inch (CPI) from 5 to 30, and a static electricity
charge of less than 1.0 at 65% relative humidity, and wherein said
sliver has a fiber-to-fiber cohesion energy of at least 10,000
Joules.
[0015] A carded sliver is continuous bundle or strand of loose
untwisted fibers that are aligned generally relatively parallel to
each other. This alignment is conducted by subjecting the fibers to
a carding process.
[0016] The slivers and spun yarns of the present invention may be
formed according to any suitable process. The process of forming
slivers from staple fibers starts begins with feeding staple fibers
to a carding machine, and optionally blending the CA staple fibers
with fibers of other non-cellulose acetate materials. If the CA
staple fibers are blended with other natural fibers, those natural
fibers may optionally be separated from foreign objects such as
dirt, seeds, and other foreign items through a picking process and
formed into a lap. The CA staple fibers contained in a bale may be
blended with other baled fibers by opening each bale and feeding
the fibers to a blending machine. Blending can occur during
formation of the lap, in the carding operation, or during the
drawing out operation, but desirably into or before the carding
process. The staple fibers can be opened and tufted to pull the
fibers apart before being fed to the carding machine.
[0017] The carding process can be by hand, or processed through any
conventional carding equipment, including drum carders, cottage
carders, and industrial carders. Generally, in the carding process,
the CA staple fibers along with staple fibers of other materials
that are not cellulose acetates (non-CA staple fibers) are placed
on a conveyor, or card, and are passed through a number of
cylinders (or other movable surfaces) covered with fine wire
brushes, metal teeth, or other gripping surfaces. The carding
machine can be roller-doffed, fine air-doffed, or coarse air-doffed
cards. Typical carding machines consist of one large cylinder with
many teeth or fine wire brushes, and a number of smaller rollers
encased within a flat having wire brushes that surround at least a
portion of the larger roller's surface and moves counter
directional to the larger cylinder. As the surfaces move relative
to one another, the fibers are mechanically separated and aligned
in a substantially parallel direction to each other. The flat and
cylinder have small teeth or wire brushes that can get
progressively finer or closer together as the fibers are pulled
through the machine. The fibers remain on the cylinder surface and
are pulled in the same parallel direction to form a thin web that
is fed into a funnel shaped tube, thereby forcing the web to form
into a round loose strand or loose rope-like body called a sliver
or card sliver.
[0018] Optionally, the card sliver can be combed, which is a
desirable operation on natural fibers for very fine yarns intended
to make finer fabrics. In combining, fine tooth combs are applied
to the sliver to further separate and remove fibers that are too
short and further align the fibers parallel to each other.
[0019] The carded sliver is the output of a carding machine that is
not yet subjected to combing (if used) and drawing operations. The
carded sliver desirably has a total denier of at least 10,000 or
least 15,000, or at least 20,000, or at least 25,000, or at least
30,000, or at least 35,000, or at least 40,000, or at least 45,000,
or at least 50,000. In general, the sliver total denier would not
exceed 200,000, or not exceed 150,000, or not exceed 100,000, or
not exceed 80,000, or not exceed 60,000, or not exceed 50,000. For
most applications, the sliver will have a total denier of 20,000 to
80,000, or 25,000 to 60,000 or 30,000 to 60,000. If one desires to
convert the sliver denier to grains, a conversion factor of 60
grain sliver=35,000 denier is used.
[0020] Once the carded slivers are formed, after an optional
combing step, they are fed to a drawing frame where multiple
slivers are combined and drafted (reducing weight per unit length),
thereby making them longer and thinner and further straightened and
aligned, to make a more uniform sized sliver with enhanced fiber to
fiber blending within the sliver. Multiple slivers are usually
further combined to make a larger sliver or strand, which can then
also be further drawn. The drawing process improves the quality of
the slivers by straightening and aligning staple fibers within and
producing a more uniform resultant sliver. The drawing process
entails passing the slivers, optionally first through guides such
as spoons, through several pairs of rollers, with each successive
pair of rollers running at a higher speed than the preceding pair
so that the slivers are combined, reduced in size, and
substantially drafted as they move down the drawing frame. Upon
drawing, the combined liner and drafted sliver product is given a
slight twist and wound onto bobbins as rovings.
[0021] The strand, or the roving, can have a total denier of at
least 30,000, or at least 40,000, or at least 50,000, or at least
55,000, or at least 60,000. In general, the sliver total denier
would not exceed 300,000, or not exceed 200,000, or not exceed
150,000. If one desires to measure the denier in hanks, the
conversion factor of 1 hank roving=5300 denier is used. Typical
industry range for roving is 0.3 to 5.0 hank or approx 18,000 to
1000 denier respectively.
[0022] The roving wound onto bobbins can then proceed to the yarn
ring spinning operation. There are a variety of other spinning
processes from which the sliver from drawing would be used directly
without the use of a roving, such as open-end (rotor) spinning,
air-jet spinning, air-vortex spinning, and electrostatic spinning.
The CA staple fibers of the invention are well suited for any type
of spinning process used.
[0023] A common spinning process is the ring spinning process. The
roving wound onto bobbins can be passed through yet another set of
drafting rolls to lengthen the roving and obtain the desired final
thickness, and then fed through a traveler that moves at high speed
around a stationary ring encircling another bobbin mounted on a
rotating spindle. The yarn moving through the traveler is at a
slower speed that the spindle speed, thereby imparting the desired
twist to the yarn as it winds onto the bobbin. The traveler
oscillates axially to the bobbin to distribute the yarn along the
length of the bobbin, and the process accomplishes twist and
winding in one step.
[0024] Open-end spinning is also a suitable process, and differs
from ring spinning in a variety of ways. In open end spinning, the
roving step is omitted, and the slivers are instead fed to the
spinner by a stream of air. To accomplish this, the fibers in the
sliver must be separated, typically be a rotary beater, and the
separated fibers are carried by a stream of air through a tube or
duct to a rotor and deposited into a groove on the sides of the
rotor. As the rotor turns, it twists the fibers in the grooves and
the twisted yarn so produced is removed from the groove as a
constant stream of new separated fibers are fed to the rotor
groove.
[0025] The CA staple fibers in the carded slivers are formed from
one or more kinds of cellulose acetate. The cellulose acetate may
be formed from cellulose diacetate, cellulose triacetate, or
mixtures thereof. The cellulose acetate has a degree of
substitution in the range of from 1.9 to 2.9. As used herein, the
term "degree of substitution" or "DS" refers to the average number
of acetyl substituents per anhydroglucose ring of the cellulose
polymer, wherein the maximum degree of substitution is 3.0. In some
cases, the cellulose acetate used to form fibers as described
herein may have an average degree of substitution of at least about
1.95, 2.0, 2.05, 2.1, 2.15, 2.2, 2.25, or 2.3 and/or not more than
about 2.9, 2.85, 2.8, 2.75, 2.7, 2.65, 2.6, 2.55, 2.5, 2.45, 2.4,
or 2.35, with greater than 90, 91, 92, 93, 94, 95, 96, 97, 98, or
99 percent of the cellulose acetate having a degree of substitution
greater than 2.15, 2.2, or 2.25. Desirably, greater than 90 weight
percent, or greater than 95%, or greater than 98%, or greater than
99%, and up to 100 wt. % of the total acyl substituents are acetyl
substituents (C2). Desirably, the cellulose acetate has no acyl
substituents having a carbon number of greater than 2.
[0026] The cellulose acetate may have a weight-average molecular
weight (Mw) of not more than 90,000, measured using gel permeation
chromatography with N-methyl-2-pyrrolidone (NMP) as the solvent. In
some case, the cellulose acetate may have a molecular weight of at
least about 10,000, at least about 20,000, 25,000, 30,000, 35,000,
40,000, or 45,000 and/or not more than about 100,000, 95,000,
90,000, 85,000, 80,000, 75,000, 70,000, 65,000, 60,000, or
50,000.
[0027] The cellulose acetate or other CA staple may be formed by
any suitable method. In some cases, cellulose acetate may be formed
by reacting a cellulosic material such as wood pulp with acetic
anhydride and a catalyst in an acidic reaction medium to form a
cellulose acetate flake. The flake may then be dissolved in a
solvent, such as acetone or methyl ethyl ketone, to form a "solvent
dope," which can be filtered and sent through a spinnerette to form
CA staple fibers. In some cases, up to about 1 weight percent or
more of titanium dioxide or other delusterant may be added to the
dope prior to filtration, depending on the desired properties and
ultimate end use of the fibers.
[0028] In some cases, the solvent dope or flake used to form the CA
staple fibers may include few or no additives in addition to the
cellulose acetate. Such additives can include, but are not limited
to, plasticizers, antioxidants, thermal stabilizers, pro-oxidants,
acid scavengers, inorganics, pigments, and colorants. In some
cases, the CA staple fibers as described herein can include at
least about 90, 90.5, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95,
95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, 99.5, 99.9, 99.99, 99.995,
or 99.999 percent cellulose acetate, based on the total weight of
the fiber. Fibers formed according to the present invention may
include not more than about 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6,
5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.5, 0.1, 0.01, 0.005, or
0.001 weight percent of additives other than cellulose acetate,
including the specific additives listed herein.
[0029] At the spinnerette, the solvent dope can be extruded through
a plurality of holes to form continuous cellulose acetate
filaments. At the spinnerette, filaments may be drawn to form
bundles of several hundred, or even thousand, individual filaments.
Each of these bundles, or bands, may include at least 100, or at
least 150, or at least 200, or at least 250, or at least 300, or at
least 350, or at least 400 and/or not more than 1000, or not more
than 900, or not more than 850, or not more than 800, or not more
than 750, or not more than 700 fibers. The spinnerette may be
operated at any speed suitable to produce filaments and bundles
having desired size and shape.
[0030] Multiple bundles may be assembled into a tow band such as,
for example, a crimped or uncrimped tow band. The tow band may be
of any suitable size and, in some embodiments, may have a total
denier of at least about 10,000, or at least 15,000, or at least
20,000, or at least 25,000, or at least 30,000, or at least 35,000,
or at least 40,000, or at least 45,000, or at least 50,000, or at
least 75,000, or at least 100,000, or at least 150,000, or at least
200,000, or at least 250,000, or at least 300,000. Alternatively,
or in addition, the total denier of the tow band can be not more
than about 5,000,000, or not more than 4,500,000, or not more than
4,000,000, or not more than 3,500,00, or not more than 3,000,000,
or not more than 2,500,000, or not more than 2,000,000, or not more
than 1,500,000, or not more than 1,000,000, or not more than
900,000, or not more than 800,000, or not more than 700,000, or not
more than 600,00, or not more than 500,000, or not more than
400,000, or not more than 350,000, or not more than 300,000, or not
more than 250,000, or not more than 200,000, or not more than
150,000, or not more than 100,000, or not more than 95,000, or not
more than 90,000, or not more than 85,000, or not more than 80,000,
or not more than 75,000, or not more than 70,000.
[0031] The individual filaments, which are extruded in a generally
longitudinally aligned manner and which ultimately form the tow
band, are of a particular size. The linear denier per filament
(weight in g of 9000 m fiber length), or DPF, of the CA filaments
in the tow band and of the corresponding staple fibers in the
sliver and yarn, are within a range of 0.5 to less than 3, or from
1.0 to less than 3, measured according to ASTM D1577-01 using the
FAVIMAT vibroscope procedure. Desirably, the DPF of the filaments,
and of the corresponding staple fibers, are within a range of 1.0
to 2.5, or 1.0 to 2.2, or 1.0 to 2.1, or more desirably from 1.0 to
2.0, or 1.0 to less than 2.0, or 1.0 to 1.9, or 1.1 to 1.9.
[0032] The individual filaments discharged from the spinnerette,
and the corresponding staple fibers, have a substantially round
cross-sectional shape, but in an acetone, solvent-spun process the
cross section will somewhat irregular or crenulated due to
collapsing of the hardened surface. As used herein, the term
"cross-section" generally refers to the transverse cross-section of
the filament measured in a direction perpendicular to the direction
of elongation of the filament. The cross-section of the filament
may be determined and measured using Quantitative Image Analysis
(QIA). Staple fibers may have a cross-section similar to the
filaments from which they were formed.
[0033] The cross-sectional shape of an individual filament may also
be characterized according to its deviation from a round
cross-sectional shape. In some cases, this deviation can be
characterized by the shape factor of the filament, which is
determined by the following formula: Shape
Factor=Perimeter/(4.pi..times.Cross-Sectional Area).sup.2. In some
embodiments, the shape factor of the individual cellulose acetate
(or other CA staple) filaments can be from 1 to 2, or 1 to 1.8, or
1 to 1.7, or 1 to 1.5, or 1 to 1.4, or 1 to 1.25, or 1 to 1.15, or
1 to 1.1. The shape factor of filament having a perfect round
cross-sectional shape is 1. The shape factor can be calculated from
the cross-sectional area of a filament, which can be measured using
QIA.
[0034] After multiple bundles are assembled into a tow band, it may
be passed through a crimping zone wherein a patterned wavelike
shape may be imparted to at least a portion, or substantially all,
of the individual filaments. Imparting crimp is necessary to allow
the staple fibers to be separated and oriented in the carding
operation, and to provide a measure of needed cohesion needed to
prevent a sliver from falling apart.
[0035] A suitable type of mechanical crimper is a "stuffing box" or
"stuffer box" crimper that utilizes a pair of nip rollers to force
the tow band into the restriction of stuffer box just downstream of
the rolls. The resulting compressive forces on the fiber cause the
fibers to buckle, crimp and interlock into a cohesive tow band.
Examples of equipment suitable for imparting crimp to the filaments
are described in, for example, U.S. Pat. Nos. 9,179,709; 2,346,258;
3,353,239; 3,571,870; 3,813,740; 4,004,330; 4,095,318; 5,025,538;
7,152,288; and 7,585,442, each of which is incorporated herein by
reference to the extent not inconsistent with the present
disclosure. In some cases, the crimping step may be performed at a
rate of at least about 50 m/min (75, 100, 125, 150, 175, 200, 225,
250 m/min) and/or not more than about 750 m/min (475, 450, 425,
400, 375, 350, 325, or 300 m/min).
[0036] The low denier CA staple fibers of the invention are
susceptible to breakage by the normal frequency of crimps imparted
to higher denier fibers typically used in cigarette filter tow.
However, as noted above, crimping is necessary component of the
fiber to form a cohesive sliver and spun yarn. A low frequency of
crimps is necessary to form fibers that exhibit minimal breakage
and a high degree of retained tenacity. As used herein, the term
"retained tenacity" refers to the ratio of the tenacity of a
crimped filament (or staple fiber) to the tenacity of an identical
but uncrimped filament (or staple fiber), expressed as a percent.
For example, a crimped fiber having a tenacity of 1.3
gram-force/denier (g/denier) would have a retained tenacity of 87
percent if an identical but uncrimped fiber had a tenacity of 1.5
g/denier.
[0037] The cellulose acetate filaments crimped according to the
present invention are capable of having a retained tenacity of at
least about 60%, or at least 65%, or at least 70%, or at least 75%,
or at least 80%, or at least 85%, or at least 90%, or at least 95%.
The retained tenacity may be 100 percent in some cases. In some
cases, the final CA staple fibers may exhibit similar retained
tenacities as compared to identical but uncrimped staple
fibers.
[0038] Crimping may be performed such that the final staple fibers
have a crimp frequency of at least 5, or least 7, or at least 8, or
at least 9, or at least 10, or at least 12, and up to 30, or up to
25, or up to 20, or up to 19 crimps per inch (CPI), measured
according to ASTM D3937. Higher CPI than 30 will result in excess
breakage and low retained tenacity, resulting in lint formation and
fiber loss. Fewer than 5 CPI is insufficient to properly card the
fibers or retain the cohesion of the sliver. Desirably, the CPI is
from 10 to 20.
[0039] The ratio of the CPI to the DPF is a useful measure to
ensure that the proper CPI is imparted for a given DPF and retain
the balance of necessary crimp frequency and tenacity for a given
DPF. Suitable ratios of CPI:DPF include from 6:1 to 30:1, or 6:1 to
20:1, and especially 6:1 to 14:1, or 7:1 to 12:1.
[0040] When crimped, the crimp amplitude of the fibers may vary and
can, for example, be at least about 0.85, or at least 0.90, or at
least 0.93, or at least 0.96, or at least 0.98, or at least 1.00,
or at least 1.04 mm. Additionally, or in the alternative, the crimp
amplitude of the fibers can be up to 1.75, or up to 1.70, or up to
1.65, or up to 1.55, or up to 1.35, or up to 1.28, or up to 1.24,
or up to 1.15, or up to 1.10, or up to 1.03, or up to 0.98 mm.
[0041] Additionally, the final staple fibers may have a crimp ratio
of at least about 1:1. As used herein, "crimp ratio" refers to the
ratio of the non-crimped tow length to the crimped tow length. In
some embodiments, the staple fibers may have a crimp ratio of at
least about 1:1, at least about 1.1:1, at least about 1.125:1, at
least about 1.15:1, or at least about 1.2:1.
[0042] Crimp amplitude and crimp ratio are measured according to
the following calculations, with the dimensions referenced being
shown in FIG. 1: Crimped length (L.sub.c) is equal to the
reciprocal of crimp frequency (1/crimp frequency), and the crimp
ratio is equal to the straight length (L.sub.0) divided by the
crimped length (L.sub.0:L.sub.c). The amplitude (A) is calculated
geometrically, as shown in FIG. 1, using half of the straight
length (L.sub.0/2) and half of the crimped length (L.sub.c/2). The
uncrimped length is simply measured using conventional methods.
[0043] After crimping, the fibers may be dried in a drying zone in
order to reduce the moisture (total of water and solvent) content
of the tow band. In some cases, the drying zone may be sufficient
to reduce the final moisture content of the tow band to not more
than about 9, or less than 8.5, or less than 8, or less than 7.5,
or less than 7, or less than 6.5, or less than 6 weight percent
based on the total weight of the yarn. Typically, the moisture
content does not drop below about 3.5 wt. % or below about 4 wt. %.
Any suitable type of dryer can be used such as, for example, a
forced air oven, a drum dryer, or a heat setting channel. The dryer
may be operated at any temperature and pressure conditions that
provide the requisite level of drying without damaging the
yarn.
[0044] Once dried, the tow band may be fed to the cutting zone, or
optionally first baled and the resulting bales may be introduced
into a cutting zone, wherein the elongated tow bands may be cut
into staple fibers. The staple fibers of the present invention may
be cut to a length that is dependent upon the application needs.
Unexpectedly, the cut length also influences the cohesion of the
sliver and ability to successfully spin a yarn at a given denier. A
successful spun yarn spin at a given denier and staple fiber length
may require adjusting the staple cut length at a lower DPF when all
other factors are constant. The staple fiber length is generally in
the range of at least 5 mm and up to 150 mm. Other examples if
desirable cut lengths include a cut length of at least 10 mm, or at
least 11 mm, and not more than about 100 mm, or not more than 90
mm, or not more than 80 mm, or not more than 60 mm, or not more
than 55 mm, or not more than 50 mm, or not more than 45 mm, or not
more than 40 mm, or not more than 38 mm, or not more than 35 mm, or
not more than 32 mm, or not more than 30 mm, or not more than 28
mm, or not more than 26 mm. Examples of cut length ranges include
from 10 to 55 mm, or 10 to 50 mm, or 10 to 45 mm, or from 11 to 38
mm, or from 11 to 26 mm.
[0045] Any suitable type of cutting device may be used that can cut
the filaments to a desired length without excessively damaging the
fibers. Examples of cutting devices can include, but are not
limited to, rotary cutters, guillotines, stretch breaking devices,
reciprocating blades, and combinations thereof. Once cut, the
staple fibers may be baled or otherwise bagged or packaged for
subsequent transportation, storage, and/or use.
[0046] The sliver obtained from the CA staple fibers has a
fiber-to-fiber cohesion energy of at least 10,000 Joules (J), or at
least 12,000 J, or at least 15,000 J, or at least 17,000 J, or at
least 20,000 J. The fiber-to-fiber cohesion energy desirably does
not have a cohesion energy of more than 30,000 J to ensure that the
sliver can be adequately drawn consistently and without fiber
breakage. The sliver fiber-to-fiber cohesion energy is influenced
by a number of factors, including cut length, CPI, denier, finish
coating level and type to adjust the fiber to fiber and fiber to
metal coefficients of dynamic friction, static electricity charges,
and fiber material. Fibers made for use in and formed into sliver
require a greater F/F CODF relative to fibers for use in or made
into many non-woven applications due to the processes for making
the sliver that requires good fiber to fiber cohesion and due to
downstream processing of the sliver, such as in drawing operations
that subject the slivers to elongation yet require the slivers to
maintain their cohesion and integrity. Compared to non-woven
applications, the F/F CODF is higher for spun yarn applications in
order to retain the cohesive energy and strength of a sliver, but
not so high as to cause it to break when drawn and elongated with
conventional equipment.
[0047] The fiber-to-fiber cohesion energy of the carded sliver is
determined by the rotor ring test. The test instrument and
procedure were developed at the institute of Textile Technology,
Denkendorf, Germany. A small amount of pre-opened fibers (2-3
grams) is presented to a feed roll turning at 5 revolutions per
minute from a feed chute. The feed roll transfers the fibers to the
opener roll spinning at 4000 revolutions per minute by means of a
carding action between the cylinders. Fibers are transported to the
feed zone from the opening roll by the action of the partial vacuum
and centrifugal force, and then they deposit into a rotor cup
turning at 10,000 revolutions per minute through air transport. A
fiber ring is formed in the rotor, which consists mainly of
parallel fibers. The energy (joules) required to drive the opening
cylinder at a constant speed is measured. Testing is performed at
65% RH and 70.degree. F.
[0048] Examples of suitable fiber-to-fiber cohesion energy of the
slivers range from 10,000 J to 30,000 J, or from 10,000 J to 28,000
J, or from 10,000 J to 25,000 J, or from 10,000 J to 23,000 J, or
from 10,000 J to 20,000 J, or from 12,000 J to 30,000 J, or from
12,000 J to 28,000 J, or from 12,000 J to 25,000 J, or from 12,000
J to 23,000 J, or from 12,000 J to 20,000 J, or from 15,000 J to
30,000 J, or from 15,000 J to 28,000 J, or from 15,000 J to 25,000
J, or from 15,000 J to 23,000 J, or from 15,000 J to 20,000 J, or
from 17,000 J to 30,000 J, or from 17,000 J to 28,000 J, or from
17,000 J to 25,000 J, or from 17,000 J to 23,000 J, or from 17,000
J to 20,000 J.
[0049] An alternative method for describing the cohesive energy to
a sliver is to conduct a staple pad friction test on the staple
fibers used to make the sliver and calculate the scroop value. The
scroop value, measured as the difference between static and dynamic
pulling forces, of the coated fibers described herein can be less
than 160 grams-force (g). In some embodiments, the coated staple
fibers may exhibit a scroop value of at least about 10, or at least
15, and desirably at least 20, or at least 23, or at least 25, or
at least 28, or at least 30, or at least 35, or at least 40, or at
least 45, or at least 50, or at least 55, or at least 60, or at
least 65, or at least 70, or at least 75, or at least 80, or at
least 85, or at least 90, in each case in grams, and desirably not
more than 200, or not more than 180, or not more than 160, or not
more than 180, or not more than 140, or not more than 120, in each
case in grams. Staple fibers with lower cohesion, as indicated by a
lower scroop values, do not have sufficient cohesive energy to form
slivers that retain their integrity and strength and that can be
adequately processed or drawn. Staple fibers having a scroop value
in excess of 1 or even 0.8. The static and dynamic coefficients of
friction and the resulting scroop value may be calculated from the
staple pad friction method described in U.S. Pat. Nos. 5,683,811
and 5,480,710, but using an Instron 5966 series machine or is
equivalent, rather than an Instron 1122 machine. The fiber-to-fiber
static friction is determined as described in the '710 patent as
the maximum threshold pulling force at low pulling speed upon
reaching equilibrium pulling behavior, and the fiber-to-fiber
dynamic friction is similarly calculated, but is the minimum
threshold level of force as the staple pad traverses a slip-stick
behavior. The scroop is calculated as the difference between static
and dynamic friction pulling forces with units of gram-force.
[0050] A more detailed description for determining the
fiber-to-fiber coefficient of friction in the staple pad friction
method is as follows. The coefficient of friction test fixture is a
fixed horizontal table and a moveable sled. Both the table and sled
can be covered with test material. A tow line attaches the sled to
a low force load cell with a pulley guiding the tow line during the
test. The fixture is mounted to the base of the test instrument and
as the crosshead/load cell moves, the sled is pulled across the
horizontal table.
[0051] Data is recorded from the load cell during the test and
analyzed to determine both static and dynamic friction. Static
friction is typically the maximum peak force on the load curve
required to initiate movement of the sled and dynamic friction is
average force on the load curve recorded throughout the total
length of travel of the sled. The staple pad coefficient of
friction is defined as the average of the static and dynamic
friction forces divided by the mass of the sled, while the scroop
value is the difference between the static and dynamic forces.
[0052] The apparatus includes a Mettler Balance, an air-jet type
device to assist in disentangling and opening staple fiber sample,
a mini-carding machine or equivalent machine capable of orienting
staple fiber sample to produce test fiber pad, a universal
Tensile/Compression Tester: Instron Model 5966 or equivalent, a
fixed steel horizontal table with fixed pulley:
200W.times.360L.times.13H mm, a steel moveable sled:
63W.times.65L.times.6H mm steel block weighing 200 grams with hook
attachment, a steel weight: 1 kg.
[0053] The fiber specimen preparation and test apparatus setup is
as follows: [0054] 1. Process approximately 50 grams of cut staple
crimped fiber through an air jet to introduce an opening effect on
the individual fibers. [0055] 2. Take two samples, each weighing
approximately 5 grams of the opened fiber, and process through
mini-carding machine to form two fiber pads each measuring
75W.times.225L.times.50 Hmm. [0056] 3. Using a Universal
Tensile/Compression Tester with a 5 to 10 kN load cell, attach the
coefficient of friction test fixture. [0057] 4. Attach with tape
sheet 50 grit sand paper to the fixed steel horizontal table.
[0058] 5. Attach with tape a second sheet of 50 grit sand paper to
the bottom of the steel moveable sled and attach the toe line to
the load cell of the Universal Tensile/Compression Tester, so that
when the load cell mechanism travels upward, the toe line will pull
on the steel moveable sled across the top of the fixed steel
horizontal table. [0059] 6. Place one sample fiber pad on the sand
paper taped to the fixed steel horizontal table. [0060] 7. Place
the second fiber pad on top of the first pad running lengthways
along the length of the length of the fixed steel horizontal table.
[0061] 8. Place steel moveable sled on top of top fiber pad and set
steel weight on top of steel moveable sled. [0062] 9. Set up the
Universal Tensile/Compression Tester such that the crosshead head
and load cell travel at a rate of 150 mm/min and the length of
travel is 150 mm. [0063] 10. Test the top fiber pad directionally
in a forward direction, then turn the pad 180 degrees and repeat
the test so that the pad has been tested twice in opposite
directions. [0064] 11. Flip the top fiber pad and repeat step 10.
[0065] 12. Record and report the static and dynamic friction forces
and calculate coefficient of friction as stated above.
[0066] Coated staple fibers of the present invention may exhibit a
fiber-to-fiber staple pad friction coefficient of friction of at
least 0.20, or at least 0.25, or at least 0.30, and desirably at
least 0.35, or at least 0.4, or at least 0.45, or at least 0.55, or
at least 0.6, and/or not more than about 0.9, or not more than
0.85, and desirably not more than 0.80, or not more than 0.75, or
not more than 0.70, or not more than 0.65, or not more than 0.6, or
not more than 0.55. Staple fibers having a fiber to fiber staple
pad friction above 0.9 are problematic in that the fibers tend to
break, thereby increasing short fiber content, and below 0.2 a
sliver cannot be formed or a sliver with poor integrity that cannot
be wound or drawn is formed.
[0067] Additionally, or in the alternative, the coated staple
fibers may exhibit a fiber-to-metal staple pad friction coefficient
of friction of at least about 0.10, 0.15, 0.20, or 0.25 and/or not
more than about 0.55, 0.50, 0.45, 0.40, 0.35, or 0.30, measured as
described in U.S. Pat. No. 5,683,811, the entire disclosure of
which is incorporated herein by reference to the extent not
inconsistent with the description herein.
[0068] In one embodiment, the CA staple fibers contained in the
carded sliver, spun yarn, and textile fabric have an untwisted F/F
CODF (also called a fiber to fiber sliding friction) between 0.11
to 0.20 as measured by ASTM D3412/3412M-13 on filament yarn. To
determine the F/F CODF of the fibers of a sliver, uncrimped
continuous filaments are formed that have the same composition,
denier, shape, and CPI as the filaments used to make the CA staple
fiber, or if available, the continuous filaments used to make the
CA staple fiber are used, and formed into a filament yarn, and
conditioned at 70.degree. F. and 65% relative humidity for 24 hours
before testing. The filament yarn is measured according to ASTM
D3412/3412M-13, with the exception that only 1 twist is used, the
rate is at 20 m/min, and the yarn is tested on a Constant Tension
Transport with Electronic Drive (CTT-E) set up according to FIG. 1
in the ASTM procedure at an input tension of 10 grams. The values
obtained by this method are deemed to be the F/F CODF of the CA
staple fibers in the sliver.
[0069] If the sliver has a F/F CODF below 0.11, the sliver likely
will not retain its integrity in the drawing process and will pull
apart, particularly if more than 10 wt. % of CA staple fiber is
used in the blend of staple fibers. If the sliver has a F/F CODF of
greater than 0.20, the drawing process will tend to exceed the
tenacity of the sliver especially as the CA staple fiber content
increases. Desirably, the F/F CODF is from 0.11 to 0.20, or from
0.11 to less than 0.20, or from 0.11 to 0.19, or from 0.11 to 0.18,
or from 0.11 to 0.17, or from 0.11 to 0.16, or from 0.11 to 0.15,
or from 0.12 to 0.20, or from 0.12 to less than 0.20, or from 0.12
to 0.19, or from 0.12 to 0.18, or from 0.12 to 0.17, or from 0.12
to 0.16, or from 0.12 to 0.15.
[0070] In addition to having the desirably F/F CODF, the CA staple
fibers contained in the carded sliver, spun yarn, and textile
fabric also desirably have a fiber to metal coefficient of dynamic
friction (F/M CODF), as measured on filament yarn, of less than
0.80. To determine the F/M CODF of the fibers of a sliver, the
continuous filaments used to make the CA staple fiber are formed
into a filament yarn, conditioned at 70.degree. F. and 65% relative
humidity for 24 hours, and measured according to ASTM
D3108/D3108M-13 at 100 m/min, with an input tension of 10 grams,
and on a CTT-E instrument set up according FIG. 2 in the ASTM
D3412/3412M-13 procedure.
[0071] Frictional forces are exerted through the fiber to metal
contact at many stages of the sliver to spun yarn stages, including
as the carding machine, drawing, roving, and spinning. These
frictional forces can result in fiber fibrillation and weakening of
the fiber to the point of breakage, resulting in the development of
short fiber content and in some cases sliver breakage, especially
at higher CA staple fiber content. Desirably, the F/M CODF not more
than 0.70, or not more than 0.65, or not more than 0.60, or not
more than 0.59, or not more than 55, or not more than 0.52, or nor
more than 0.50, or not more than 0.48, or not more than 0.47.
Desirable ranges include 0.30 to 0.80, or 0.30 to 0.70, or 0.30 to
0.65, or 0.30 to 0.60, or 0.40 to 0.80, or 0.40 to 0.70, or 0.40 to
0.65, or 0.40 to 0.60, or 0.45 to 0.80, or 0.45 to 0.70, or 0.45 to
0.65, or 0.45 to 0.60, or 0.48 to 0.80, or 0.48 to 0.70, or 0.48 to
0.65, or 0.48 to 0.60, or 0.50 to 0.80, or 0.50 to 0.70, or 0.50 to
0.65, or 0.50 to 0.60.
[0072] Static electricity can be a nuisance to the user of the
textile fabric and can cause processing problems in the production
of spun yarns and textile fabrics. Since moisture is an excellent
anti-static agent, the problem of static build up is particularly
evident if the fibers are hydrophobic. In most dry textile fabric
processes, fibers and fabrics move at high speeds over various
surfaces and against each other, which can generate triboeectric
static charges resulting from frictional forces. Static electricity
build up on the fibers tends to make the fibers repel each other,
leading to a reduction in sliver cohesion and other downstream
processing problems for yarn spinning. Additionally, static charges
will affect fabric materials handling and is a nuisance to
consumers dealing with clinging garments and the small electrical
shocks caused by walking on carpets in even moderate to high
humidity conditions.
[0073] Accordingly, in one embodiment, which can include the above
stated F/F CODF and/or the F/M CODF, the CA staple fibers used to
make the sliver from carded staple fibers have a static electricity
charge of less than 1.0 at 65% relative humidity. The static
electricity charge on the CA staple fibers will influence the
cohesiveness of the sliver by reducing the fiber to fiber
repulsion, and thereby retain the cohesiveness of the sliver. The
sliver and carded staple fibers are deemed to have been made with
CA staple fibers having a static electricity charge of no more than
1.0 when filaments used to make the staple fibers used in the
sliver have a static electricity charge of less than 1.0. The test
method for determining the static electricity charge of the CA
staple fibers used to make the sliver is as follows. The sample is
a filament yarn used to make the staple fibers in the sliver. The
filament yarn is exposed to a controlled environment at 65%
relative humidity at 70.degree. F. for 24 hours to condition the
filament yarn. A two (2) foot section of the filament yarn is
secured at one end, the other end is held by hand while rubbing the
secured section of the filament yarn back and forth along the whole
2 foot section for 3 cycles using the side of a wooden #2 pencil.
The static electricity charge imparted to the filaments are
measured using a Simco Electrostatic Fieldmeter Model FMX-003 or
equivalent device.
[0074] The static electricity charge is desirably no more than 1.0,
or no more than 0.98, or no more than 0.96, or no more than 0.90,
or no more than 0.85, or no more than 0.80, or no more than 0.78,
or no more than 0.75, or no more than 0.70, or no more than 0.68,
or no more than 0.58, or no more than 0.60, or no more than 0.58,
or no more than 0.55, or no more than 0.50.
[0075] In addition to the cut length, filament shape, and denier,
the F/F CODF, F/M CODF, and static charge on the CA staple fibers
can be influenced by the application of a finish on the filaments
used to make the CA staple fibers. A finish applied to the CA
filaments, also called "fiber finish" or "spin finish," refers to
any suitable type of coating that, when applied to a fiber
filament: [0076] 1. modifies friction exerted by and on the fiber,
and alters the ability of the fibers to move relative to one
another and/or relative to a metal surface, or [0077] 2. reduces
static electricity build up on a fiber, or [0078] 3. both.
[0079] Desirably, at least one finish should be applied to the
fibers that modifies the fiber to fiber coefficient of friction and
optionally the fiber to metal coefficient of friction. The same
finish may also have anti-static properties, or a second
anti-static finish can be applied.
[0080] Finishes are not the same as adhesives, bonding agents, or
other similar chemical additives which, when added to fibers,
prevent movement between the fibers by adhering them to one
another. Finishes, when applied, continue to permit the movement of
the fibers relative to one another and/or relative to other
surfaces, but may modify the ease of this movement by increasing or
decreasing the frictional forces.
[0081] Accordingly, it is desirable that the CA staple fibers have
a coating that modifies the F/F CODF within the stated limits as
compared to an identical but uncoated fiber. Although the
relatively higher CPI does impart a measure of fiber to fiber
dynamic friction, more friction is required when the staple fibers
are formed into slivers and spun yarn because a higher cohesive
energy is required to impart the necessary integrity to the slivers
and the elongation and tenacity strength to the spun yarn. Further,
as noted above, fibers made for use in and formed into sliver
require a greater F/F CODF relative to fibers for use in or made
into many non-woven applications.
[0082] A finish that imparts both an enhanced fiber to fiber
coefficient of static and dynamic friction, and an enhanced
anti-static electricity build up, applied in one step is desirable
so that only one application of finish to the fiber is required.
However, the staple fibers may include at least two finishes
applied to all or a portion of the staple fiber surface in one step
or in multiple steps at one or more points during the fiber
production process. When two or more finishes are applied to the
fibers, the finishes may be applied in one step as a blend of two
or more different finishes, or the finishes may be applied
separately at different steps/locations during the process. For
example, in some cases, the staple fibers may be at least partially
coated with a spinning or spin finish applied to the filaments at
or between filament spinning and before crimping to facilitate the
filament spinning and/or crimping steps described previously. The
finish, including an anti-static finish, may be added to the fiber
at the filament spinning step or between fiber spinning and
gathering the filaments into a bundle. Alternatively, or in
addition, the finish (which can include an anti-static finish) may
be applied at any point at or after filament spinning and before
the cutting step, and can be applied to individual filaments,
bundles, or the tow band.
[0083] Any suitable method of applying the finish may be used and
can include, for example, spraying, wick application, dipping, or
use of squeeze, lick, or kiss rollers.
[0084] The cumulative amount of all finish applied will depend on
the type of finishes, the fiber denier, cut length, and type of CA
used that would impart to the CA staple fibers a F/F CODF and a
static electricity charge within the limits described above. When
used, the finishes may be of any suitable type and can be present
on the filaments, tow band, CA staple fibers, and CA staple fibers
present in the sliver and spun yarn in an amount of at least about
0.05, or at least 0.10, or at least 0.15, or at least 0.20, or at
least 0.25, or at least 0.30, or at least 0.35, or at least 0.40,
or at least 0.45, or at least 0.50, or at least 0.55, or at least
0.60 percent finish-on-yam (FOY) relative to the weight of the
dried CA fiber. Alternatively, or in addition, the cumulative
amount of finish may be present in an amount of less than 2.0, or
not more than 1.8, or not more than 1.5, or not more than 1.2, or
not more than 1.0, or not more than 0.9, or not more than 0.8, or
not more than 0.7 percent finish-on-yam (FOY) based on the total
weight of the dried fiber. The amount of finish on the fibers as
expressed by weight percent may be determined by solvent
extraction. As used herein "FOY" or "finish on yam" refers to the
amount of finish on the yarn less any added water, and in this
context, yarn does not refer to spun yarn, but rather the CA tow
band which would be representative of and be the same amount on CA
staple fibers, and in the context of a sliver, the percentage would
be based on the CA staple fibers in the sliver. One or two or more
types of finishes may be used. Desirably, the cumulative amount of
finish on the fibers is from 0.10 to 1.0, or 0.10 to 0.90, or 0.10
to 0.80, or 0.10 to 0.70, or 0.15 to 1.0, or 0.15 to 0.90, or 0.15
to 0.80, or 0.15 to 0.70, or 0.20 to 1.0, or 0.20 to 0.90, or 0.20
to 0.80, or 0.20 to 0.70, or 0.25 to 1.0, or 0.25 to 0.90, or 0.25
to 0.80, or 0.25 to 0.70, or 0.30 to 1.0, or 0.30 to 0.90, or 0.30
to 0.80, or 0.30 to 0.70, each as % FOY.
[0085] The anti-static finish may be a cationic, a non-ionic, or an
anionic finish and may be in the form of a solution, an emulsion,
or a dispersion. The anti-static finish may be an aqueous emulsion
and it may or may not include any type of hydrocarbon, oil
including silicone oil, waxes, alcohol, glycol, or siloxanes. The
specific type of anti-static finish applied to the filaments or
fibers may depend, at least in part, on the final application for
which the staple fibers will be used. Examples of suitable
anti-static finishes can include, but are not limited to, phosphate
salts, sulfate salts, ammonium salts, and combinations thereof.
Minor amounts of other components, such as surfactants, may also be
present in order to enhance the stability and/or processability of
the finish, and/or to make it more desirable for the intended end
use of the fiber (e.g., non-irritating when the fiber will be
contacted with a user's skin). Further, depending on the end use of
the CA staple fibers, the finish may be compliant with various
Federal and state regulations and can be, for example, non-animal,
Proposition 65 compliant, and/or FDA food contact approved.
[0086] The anti-static finish will impact the interaction of the
coated fiber with water by modifying the hydrophiicity of the
uncoated fiber to make it more hydrophilic. Use of an anti-static
finish may impart additional moisture to the fiber itself. In some
embodiments, addition of the anti-static finish results in at least
0.05%, or at least 0.1%, or at least 0.15%, or at least 0.20%, or
at least 0.30%, or at least 0.50%, or at least 0.80%, and up to
1.5%, or up to 1.0% moisture added to the fiber.
[0087] The carded slivers made with the CA staple fibers of the
invention desirably have a low coefficient of variation. Carded
slivers made with other synthetic fibers often have thick and thin
spots along the length of the sliver which manifests itself as
having weight variations along a unit length of the resultant spun
yarn. A carded sliver having a low coefficient of variation will be
uniform, made with fibers having a fairly uniform crimp frequency
and finish, and have a good coefficient of friction. The slivers
containing the CA staple fibers described herein can have a
coefficient of variation (CVm) of no more than 4.5%, or not more
than 4.2%, or not more than 4.1%, or not more than 4.0%, or not
more than 3.8%, or not more than 3.7%, or not more than 3.6%, as
measured on 12 mm sections of sliver over 250 liner yards by the
ASTM D1425 "Unevenness of Textile Strands Using Capacitance Testing
Equipment." test method.
[0088] Examples of typical ranges of CVm values are from 1 to 4.5,
or from 1.5 to 4.5, or from 2 to 4.5, or from 2.5 to 4.5, or from
2.8 to 4.5, or from 2.9 to 4.5, or from 3.0 to 4.5, or from 3.1 to
4.5, or from 3.2 to 4.5, or from 3.3 to 4.5, or from 3.4 to 4.5, or
from 3.5 to 4.5, or from 3.6 to 4.5, or from 3.7 to 4.5, or from
3.8 to 4.5, or from 3.9 to 4.5, or from 1 to 4.2, or from 1.5 to
4.2, or from 2 to 4.2, or from 2.5 to 4.2, or from 2.8 to 4.2, or
from 2.9 to 4.2, or from 3.0 to 4.2, or from 3.1 to 4.2, or from
3.2 to 4.2, or from 3.3 to 4.2, or from 3.4 to 4.2, or from 3.5 to
4.2, or from 3.6 to 4.2, or from 3.7 to 4.2, or from 3.8 to 4.2, or
from 3.9 to 4.2, or from 1 to 4.1, or from 1.5 to 4.1, or from 2 to
4.1, or from 2.5 to 4.1, or from 2.8 to 4.1, or from 2.9 to 4.1, or
from 3.0 to 4.1, or from 3.1 to 4.1, or from 3.2 to 4.1, or from
3.3 to 4.1, or from 3.4 to 4.1, or from 3.5 to 4.1, or from 3.6 to
4.1, or from 3.7 to 4.1, or from 3.8 to 4.1, or from 3.9 to 4.1, or
from 1 to 4.0, or from 1.5 to 4.0, or from 2 to 4.0, or from 2.5 to
4.0, or from 2.8 to 4.0, or from 2.9 to 4.0, or from 3.0 to 4.0, or
from 3.1 to 4.0, or from 3.2 to 4.0, or from 3.3 to 4.0, or from
3.4 to 4.0, or from 3.5 to 4.0, or from 3.6 to 4.0, or from 3.7 to
4.0, or from 3.8 to 4.0, or from 3.9 to 4.0, or from 1 to 3.8, or
from 1.5 to 3.8, or from 2 to 3.8, or from 2.5 to 3.8, or from 2.8
to 3.8, or from 2.9 to 3.8, or from 3.0 to 3.8, or from 3.1 to 3.8,
or from 3.2 to 3.8, or from 3.3 to 3.8, or from 3.4 to 3.8, or from
3.5 to 3.8, or from 3.6 to 3.8, or from 3.7 to 3.8, or from 1 to
3.7, or from 1.5 to 3.7, or from 2 to 3.7, or from 2.5 to 3.7, or
from 2.8 to 3.7, or from 2.9 to 3.7, or from 3.0 to 3.7, or from
3.1 to 3.7, or from 3.2 to 3.7, or from 3.3 to 3.7, or from 3.4 to
3.7, or from 3.5 to 3.7, or from 3.6 to 3.7, or from 1 to 3.6, or
from 1.5 to 3.6, or from 2 to 3.6, or from 2.5 to 3.6, or from 2.8
to 3.6, or from 2.9 to 3.6, or from 3.0 to 3.6, or from 3.1 to 3.6,
or from 3.2 to 3.6, or from 3.3 to 3.6, or from 3.4 to 3.6, or from
3.5 to 3.6 in each case as a percent.
[0089] Due to the good fiber-to-fiber cohesion energy of the
sliver, the short fiber content of the sliver can be minimized.
Short fibers are fibers less than 1/2'' long. Carded slivers can be
made with a short fiber content of not more than 30%, or not more
than 28%, or not more than 26%, or not more than 25%, or not more
than 23%, or not more than 20%, or not more than 18%, or not more
than 15%, or not more than 13%, or not more than 10%, or not more
than 8%, or not more than 6%, or not more than 5%, or not more than
4%, in each case as weight percent, as determined by using the
Keisokki Fiber Length Distribution Tester. The tester measures a
fiber tuft or beard nipped on a sample comb by an optical method
and automatically plots the Fibrogram from which the fiber length
distribution of the sample can be derived.
[0090] Alternatively, the carded slivers can be made with a short
fiber content of not more than 30%, or not more than 28%, or not
more than 26%, or not more than 25%, or not more than 23%, or not
more than 20%, or not more than 18%, or not more than 15%, or not
more than 13%, or not more than 10%, in each case as weight percent
as determined by using the Uster AFIS test method. This test method
is more destructive to the fibers than the Keisokki Fiber Length
Distribution Tester and will artificially generate additional short
fibers, but even under this test method, the short fiber content
can be under 30 wt. %, or under 25 wt. %, or under 20 wt %, or
under 15 wt. %.
[0091] The CA staple fibers used in the slivers desirably exhibit
high tenacity to avoid breakage and short fiber formation during
carding and drawing. For example, in some embodiments, the CA
staple fibers used to make the slivers, spun yarn, and textile
fabrics may exhibit a tenacity of at least about 0.80, or at least
about 0.85, or at least about 0.90, or at least about 0.95, or at
least about 1.0, or at least about 1.05, or at least about 1.1, or
at least about 1.15, or at least about 1.20, or at least about
1.25, or at least about 1.30 grams-force/denier (g/denier) and/or
not more than 2.50, or not more than 2.45, or not more than 2.40,
or not more than 2.35, or not more than 2.30, or not more than
2.25, or not more than 2.20, or not more than 2.15, or not more
than 2.10, or not more than 2.05, or not more than 2.00, or not
more than 1.95, or not more than 1.90, or not more than 1.85, or
not more than 1.80, or not more than 1.75, or not more than 1.70,
or not more than 1.65, or not more than 1.60, or not more than
1.55, or not more than 1.50, or not more than 1.45, or not more
than 1.40 g/denier, measured according to ASTM D3822 on a filament
yarn used to make the CA staple fibers having the same composition
as the staple fibers, without mixing with other fibers. Examples of
suitable ranges of CA staple fiber tenacity include 0.8 to 2.5, or
0.8 to 2.45, or 0.8 to 2.40, or 0.8 to 2.35, or 0.8 to 2.30, or 0.8
to 2.25, or 0.8 to 2.20, or 0.8 to 2.15, or 0.8 to 2.10, or 0.8 to
2.05, or 0.8 to 2.00, or 0.8 to 1.95, or 0.8 to 1.90, or 0.8 to
1.85, or 0.8 to 1.80, or 0.8 to 1.75, or 0.8 to 1.70, or 0.8 to
1.65, or 0.8 to 1.60, or 0.8 to 1.55, or 0.8 to 1.50, or 0.8 to
1.45, or 0.8 to 1.40, 0.9 to 2.5, or 0.9 to 2.45, or 0.9 to 2.40,
or 0.9 to 2.35, or 0.9 to 2.30, or 0.9 to 2.25, or 0.9 to 2.20, or
0.9 to 2.15, or 0.9 to 2.10, or 0.9 to 2.05, or 0.9 to 2.00, or 0.9
to 1.95, or 0.9 to 1.90, or 0.9 to 1.85, or 0.9 to 1.80, or 0.9 to
1.75, or 0.9 to 1.70, or 0.9 to 1.65, or 0.9 to 1.60, or 0.9 to
1.55, or 0.9 to 1.50, or 0.9 to 1.45, or 0.9 to 1.40, or 1 to 2.5,
or 1 to 2.30, or 1 to 2.00, or 1 to 1.80, or 1 to 1.65, or 1.2 to
2.5, or 1.2 to 2.30, or 1.2 to 2.05, or 1.2 to 1.90, or 1.2 o 1.70,
or 1.3 to 2.5, or 1.3 to 2.30, or 1.3 to 2.15, or 1.3 to 2.00, or
1.3 to 1.85, or 1.3 to 1.70 g/denier.
[0092] The elongation at break of the CA staple fibers used to make
the sliver, spun yarn, or textile fabric can be at least 10%, or at
least 13, or at least 15, or at least 20, or at least 25 percent
and/or not more than about 50, or not more than 45, or not more
than 40, or not more than 35, or not more than 30 percent, measured
according to ASTM D3822. If the elongation at break is less than
10%, the slivers containing the CA staple fibers are more
susceptible to breakage at normal drawing ratios. CA staple fibers
having an elongation at break from 10 to 13% can be useful if they
also have good tenacity. Examples of more desirable ranges include
13 to 50, or 13 to 45, or 13 to 40, or 13 to 35, or 13 to 30, or 15
to 50, or 15 to 45, or 15 to 40, or 15 to 35, or 15 to 30, or 20 to
50, or 20 to 45, or 20 to 40, or 20 to 35, or 20 to 30, or 25 to
50, or 25 to 45, or 25 to 40, or 25 to 35, or 25 to 30.
[0093] The CA staple fibers having high tenacity and elongation
allow sufficient retention of sliver tenacity and elongation to
allow them to be formed into slivers and drawn across drawing
frames without breakage. The CA staple fiber has a higher or lower
tenacity and elongation at break than the fiber with which it is
blended. Therefore, the sliver and spun yarn tenacity and
elongation at break will be influenced by blend ratio of staple
fibers. Slivers and spun yarns made with the CA staple fibers
described herein have tenacity retention of at least 50%, or at
least 55%, or at least 60%, or at least 65% or at least 70%, or at
least 75%, as calculated by the tenacity of the blended sliver or
yarn/tenacity of a sliver or yarn made with the 100% of the non-CA
fiber used in the blend.times.100.
[0094] The CA staple fibers can include little or no plasticizer
and will exhibit enhanced biodegradability under industrial, home,
and soil conditions, even as compared to CA staple fibers with
higher levels of plasticizer.
[0095] In some embodiments, the fibers of the present invention can
include not more than 5, or not more than 4.5, or not more than 4,
or not more than 3.5, or not more than 3, or not more than 2.5, or
not more than 2, or not more than 1.5, or not more than 1, or not
more than 0.5, or not more than 0.25, or not more than 0.10, or nor
more than 0.05, or not more than 0.01 wt. % plasticizers, based on
the total weight of the fiber, or the fibers may include no added
plasticizer. When present, the plasticizer may be incorporated into
the fiber itself by being blended with the solvent dope or
cellulose acetate flake, or the plasticizer may be applied to the
surface of the fiber or filament by spraying, by centrifugal force
from a rotating drum apparatus, or by an immersion bath.
[0096] Examples of plasticizers that may be present, and desirably
are not present, in or on the fibers can include, but are not
limited to, aromatic polycarboxylic acid esters, aliphatic
polycarboxylic acid esters, lower fatty acid esters of polyhydric
alcohols, and phosphoric acid esters. Further examples can include,
but are not limited to, dimethyl phthalate, diethyl phthalate,
dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
dimethoxyethyl phthalate, ethyl phthalylethyl glycolate, butyl
phthalylbutyl glycolate, levulinic acid esters, dibutyrates of
triethylene glycol, tetraethylene glycol, pentaethylene glycol,
tetraoctyl pyromellitate, trioctyl trimellitate, dibutyl adipate,
dioctyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl
azelate, dibutyl azelate, dioctyl azelate, glycerol,
trimethylolpropane, pentaerythritol, sorbitol, glycerin triacetate
(triacetin), diglycerin tetracetate, triethyl phosphate, tributyl
phosphate, tributoxyethyl phosphate, triphenyl phosphate, and
tricresyl phosphate, and combinations thereof.
[0097] Additionally, the CA staple fibers of the present invention
may not have undergone additional treatment steps designed to
enhance the biodegradability of the fibers. For example, the fibers
as described herein are desirably not hydroylzed or treated with
enzymes or microorganisms. The fibers may include not more than 1,
or nor more than 0.75, or nor more than 0.5, or nor more than 0.25,
or nor more than 0.1, or nor more than 0.05, or or nor more than
0.01 weight percent of an adhesive, bonding agent or other
modifying agent. In some embodiments, the fibers may not include
any adhesive, bonding, or modifying agent and may not be formed
from any substituted or modified cellulose acetate. Modified
cellulose acetate may include cellulose acetate that has been
modified with a polar substituent, such as a substituent selected
from the group consisting of sulfates, phosphates, borates,
carbonates, and combinations thereof.
[0098] There is also provided a sliver or spun yarn retaining a
substantial portion of its elongation at break by using the CA
staple fibers described herein. The elongation at break retention
can be at least 60%, or at least 65%, or at least 70%, or at least
75%, or at least 80%, or at least 90%, or at least 95%, and can
even exceed the elongation at break of the other blended fiber
material. The method for calculating the elongation at break
retention is the elongation at break of blended sliver or
yarn/elongation at break of sliver or yarn made with 100% of the
non-CA fiber used in the blend.times.100.
[0099] Spun yarns made with the CA staple fibers can also have a
time to break of at least 0.5 seconds, or at least 0.6, or at least
0.65, or at least 0.70, or at least 0.75 seconds, as measured
according to ASTM 2256 using for testing purposes a spun yarn made
of 100% of the CA staple fibers.
[0100] The spun yarns made with the staple fibers can also have a
breaking force of at least 130, or at least 140 or at least 150,
and optionally up to 200, or up to 190 g-N, as measured according
to ASTM 2256, using for testing purposes a spun yarn made of 100%
of the CA staple fibers. Examples of suitable ranges of breaking
force include from 130 to 200, or 140 to 200, or 150 to 200, or 130
to 190, or 140 to 190, or 150 to 190 g-N.
[0101] The spun yarns made with the CA staple fibers can also have
a breaking work force of at least 600, or at least 650, or at least
700. In addition, or in the alternative, the yarns can have a
breaking work force up to 1200, or up to 1100, or up to 1000, or up
to 900 gFcm. The breaking work force is measured according to ASTM
2256, using, for testing purposes, a spun yarn made of 100% of the
CA staple fibers. Examples of suitable ranges include 600 to 1200,
or 650 to 1200, or 700 to 1200, or 600 to 1100, or 650 to 1100, or
700 to 1100, or 600 to 1000, or 650 to 1000, or 700 to 1000
gFcm.
[0102] The spun yarns also exhibit high tenacity. For example, in
some embodiments, the spun yarns made with CA staple fibers may
exhibit a tenacity of at least about 0.80, or at least about 0.85,
or at least about 0.90 gF/denier. In addition, or in the
alternative, the spun yarns may have a tenacity of up to 1.1, or
1.0 gF/denier. The tenacity of the spun yarns is measured according
to ASTM 2256, using, for testing purposes, a spun yarn made of 100%
of the CA staple fibers.
[0103] The elongation at break of the spun yarns containing the CA
staple fibers can be at least 10%, or at least 11, or at least 12,
or at least 13 percent, or at least 15 percent. In addition, or in
the alternative, the elongation at break of the spun yarns can be
up to 20%, or up to 15%, or up to 14%. The elongation at break of
the spun yarns is measured according to ASTM 2256, using, for
testing purposes, a spun yarn made of 100% of the CA staple
fibers.
[0104] The tenacity and elongation at break values described above
can also be achieved on a spun yarn having a twist multiplier
(meaning twists per inch divided by the square root of yarn count
English) of less than 4.0 and a total denier of less than 400, or
even not more than 300. These tenacity and elongation at break
values described above are achievable on a spun yarn having a twist
multiplier of less than 4.0 or 3.6 or less and a total denier of
not more than 300 or not more than 250.
[0105] The spun yarns can have a total denier of at least 100, or
at least 125, or at least 150, and up to 1000, or up to 500, or up
to 400, or up to 300 or up to 250. Suitable ranges include 100 to
1000, or 125 to 500, or 125 to 400, or 125 to 300, or 100 to 300,
or 100 to 250.
[0106] The carded slivers, spun yarn, and textile fabrics can be
made with 100% CA staple fibers or be are blends of CA staple
fibers with other fibers that are not CA staple fibers. The CA
staple fibers may be present in a sliver or spun yarn or in an
amount of at least 5, or at least 10, or at least 15, or at least
20, or at least 25, or at least 30, or at least 35, or at least 40,
or at least 45 wt. % and up to 100, or up to 90, or up to 80, or up
to 70 or up to 60, or up to 55, or up to 52, or up to 50, or up to
45, or up to 40, or up to 35, or up to 30, or up to 25, or up to
22, or up to 20 wt. %, based on the total weight of the blend. One
or more of the other fibers may be present in an amount of at least
about 5, or at least 10, or at least 15, or at least 20, or at
least 25, or at least 30, or at least 35, or at least 40, or at
least 45, or at least 50, or at least 55, or at least 60, or at
least 65, or at least 70, or at least 75, or at least 80 weight
percent. Compositions of specific blends can be determined
according to AATCC TM20A-2014, No. 1. Examples of suitable ranges
of the CA staple fibers in the sliver, spun yarn, or textile fabric
include from 5 to 70, or 5 to 65, or 5 to 60, or 5 to 55, or 5 to
50, or 5 to 45, or 5 to 40 or 5 to 35, or 5 to 30, or 5 to 25, or 5
to 25, or 5 to 20, or 10 to 70, or 10 to 65, or 10 to 60, or 10 to
55, or 10 to 50, or 10 to 45, or 10 to 40 or 10 to 35, or 10 to 30,
or 10 to 25, or 10 to 25, or 10 to 20, or 15 to 70, or 15 to 65, or
15 to 60, or 15 to 55, or 15 to 50, or 15 to 45, or 15 to 40 or 15
to 35, or 15 to 30, or 15 to 25, or 15 to 25, or 5 15 to 20, or 20
to 70, or 20 to 65, or 20 to 60, or 20 to 55, or 20 to 50, or 20 to
45, or 20 to 40 or 20 to 35, or 20 to 30, or 20 to 25 wt % based on
the weight of all fibers in the sliver, spun yarn, or textile
fabric.
[0107] Other types of fibers suitable for use in a blend with CA
staple fibers can include natural and/or synthetic fibers
including, but not limited to, cotton, rayon, viscose) or other
types of regenerated cellulose such as Cupro, Tencel, Modal, and
Lyocell cellulose, acetates such as poyvinylacetate, wool, glass,
polyamides including nylon, polyesters such as polyethylene
terephthalate (PET), poycyclohexylenedimethylene terephthalate
(PCT) and other copolymers, olefinic polymers such as polypropylene
and polyethylene, polycarbonates, poly sulfates, poly sulfones,
poyethers, acrylics, acryonitrile copolymers, polyvinylchloride
(PVC), poly lactic acid, poly glycolic acid and combinations
thereof.
[0108] In some cases, the fibers may be single-component fibers,
while, in other cases, the fibers could be multicomponent fibers
including cellulose acetate with one or more other types of
materials. Desirably, the fibers are single-component fibers.
[0109] The spun yarn formed from the staple fibers may also exhibit
desirable wicking properties. For example, in some embodiments,
spun yarn and textile fabrics formed from CA staple fiber may have
a wicking height at 5 minutes of not more than 200 mm. In some
case, the wicking height of a spun yarn as described herein can be
not more than about 175, 150, 125, 100, 90, 80, 70, 60, 50, 40, or
30 mm, measured as described in NWSP 010.1-7.3.
[0110] The textile fabrics made from spun yarns containing the CA
staple fibers of the invention also maintain good anti-piling
properties in the textile fabric as determined by ASTM 4970 using
the Martindale tester. The textile fabrics made with the CA staple
fibers described herein can have a Grade 4 or 5.
[0111] The staple fibers and nonwovens formed therefrom can be
biodegradable, meaning that such fibers are expected to decompose
under certain environmental conditions. The degree of degradation
can be characterized by the weight loss of a sample over a given
period of exposure to certain environmental conditions. In some
cases, the material used to form the staple fibers, the fibers, or
the textile fabrics produced from the fibers can exhibit a weight
loss of at least about 5, 10, 15, or 20 percent after burial in
soil for 60 days and/or a weight loss of at least about 15, 20, 25,
30, or 35 percent after 15 days of exposure to a typical municipal
composter. However, the rate of degradation may vary depending on
the particular end use of the fibers, as well as the composition of
the remaining article, and the specific test. Exemplary test
conditions are provided in U.S. Pat. Nos. 5,970,988 and
6,571,802.
[0112] The CA staple fibers as described herein can exhibit
enhanced levels of environmental non-persistence, characterized by
better-than-expected degradation under various environmental
conditions. Fibers and fibrous articles of the present invention
meet or exceed passing standards set by international test methods
and authorities for industrial compostability, home compostability,
and/or soil biodegradability.
[0113] To be considered "compostable," a material must meet the
following four criteria: (1) the material must be biodegradable;
(2) the material must be disintegrable; (3) the material must not
contain more than a maximum amount of heavy metals; and (4) the
material must not be ecotoxic. As used herein, the term
"biodegradable" generally refers to the tendency of a material to
chemically decompose under certain environmental conditions.
Biodegradability is an intrinsic property of the material itself,
and the material can exhibit different degrees of biodegradability,
depending on the specific conditions to which it is exposed. The
term "disintegrable" refers to the tendency of a material to
physically decompose into smaller fragments when exposed to certain
conditions. Disintegration depends both on the material itself, as
well as the physical size and configuration of the article being
tested. Ecotoxicity measures the impact of the material on plant
life, and the heavy metal content of the material is determined
according to the procedures laid out in the standard test
method.
[0114] The CA staple fibers can exhibit a biodegradation of at
least 70 percent in a period of not more than 50 days, when tested
under aerobic composting conditions at ambient temperature
(28.degree. C..+-.2.degree. C.) according to ISO 14855-1 (2012). In
some cases, the CA staple fibers can exhibit a biodegradation of at
least 70 percent in a period of not more than 49, 48, 47, 46, 45,
44, 43, 42, 41, 40, 39, 38, or 37 days when tested under these
conditions, also called "home composting conditions." These
conditions may not be aqueous or anaerobic. In some cases, the CA
staple fibers can exhibit a total biodegradation of at least about
71, or at least 72, or at least 73, or at least 74, or at least 75,
or at least 76, or at least 77, or at least 78, or at least 79, or
at least 80, or at least 81, or at least 82, or at least 83, or at
least 84, or at least 85, or at least 86, or at least 87, or or at
least 88 percent, when tested under according to ISO 14855-1 (2012)
for a period of 50 days under home composting conditions. This may
represent a relative biodegradation of at least about 95, or at
least 97, or at least 99, or at least 100, or at least 101, or at
least 102, or or at least 103 percent, when compared to cellulose
subjected to identical test conditions.
[0115] To be considered "biodegradable," under home composting
conditions according to the French norm NF T 51-800 and the
Australian standard AS 5810, a material must exhibit a
biodegradation of at least 90 percent in total (e.g., as compared
to the initial sample), or a biodegradation of at least 90 percent
of the maximum degradation of a suitable reference material after a
plateau has been reached for both the reference and test item. The
maximum test duration for biodegradation under home compositing
conditions is 1 year. The CA staple fibers as described herein may
exhibit a biodegradation of at least 90 percent within not more
than 1 year, measured according 14855-1 (2012) under home
composting conditions. In some cases, the CA staple fibers may
exhibit a biodegradation of at least about 91, or at least 92, or
at least 93, or at least 94, or at least 95, or at least 96, or at
least 97, 9 or at least 8, or at least 99, or or at least 99.5
percent within not more than 1 year, or the fibers may exhibit 100
percent biodegradation within not more than 1 year, measured
according 14855-1 (2012) under home composting conditions.
[0116] Additionally, or in the alternative, the fibers described
herein may exhibit a biodegradation of at least 90 percent within
not more than about 350, or not more than 325, or not more than
300, or not more than 275, or not more than 250, or not more than
225, or not more than 220, or not more than 210, or not more than
200, or not more than 190, or not more than 180, or not more than
170, or not more than 160, or not more than or not more than 150,
or not more than 140, or not more than 130, or not more than 120,
or not more than 110, or not more than 100, or not more than 90, or
not more than 80, or not more than 70, or not more than 60, or not
more than 50 days, measured according 14855-1 (2012) under home
composting conditions. In some cases, the fibers can be at least
about 97, or at least 98, or at least 99, or at least 99.5 percent
biodegradable within not more than about 70, or not more than 65,
or not more than 60, or not more than 50 days of testing according
to ISO 14855-1 (2012) under home composting conditions. As a
result, the CA staple fibers may be considered biodegradable
according to, for example, French Standard NF T 51-800 and
Australian Standard AS 5810 when tested under home composting
conditions.
[0117] The CA staple fibers can exhibit a biodegradation of at
least 60 percent in a period of not more than 45 days, when tested
under aerobic composting conditions at a temperature of 58.degree.
C. (.+-.2.degree. C.) according to ISO 14855-1 (2012). In some
cases, the fibers can exhibit a biodegradation of at least 60
percent in a period of not more than 44, or not more than 43, or
not more than 42, or not more than 41, or not more than 40, or not
more than 39, or not more than 38, or not more than 37, or not more
than 36, or not more than 35, or not more than 34, or not more than
33, or not more than 32, or not more than 31, or not more than 30,
or not more than 29, or not more than 28, or not more than 27 days
when tested under these conditions, also called "industrial
composting conditions." These may not be aqueous or anaerobic
conditions. In some cases, the fibers can exhibit a total
biodegradation of at least about 65, or at least 70, or at least
75, or at least 80, or at least 85, or at least 87, or at least 88,
or at least 89, or at least 90, or at least 91, or at least 92, or
at least 93, or at least 94, or at least 95 percent, when tested
under according to ISO 14855-1 (2012) for a period of 45 days under
industrial composting conditions. This may represent a relative
biodegradation of at least about 95, or at least 97, or at least
99, or at least 100, or at least 102, or at least 105, or at least
107, or at least 110, or at least 112, or at least 115, or at least
117, or at least 119 percent, when compared to cellulose fibers
subjected to identical test conditions.
[0118] To be considered "biodegradable," under industrial
composting conditions according to ASTM D6400 and ISO 17088, at
least 90 percent of the organic carbon in the whole item (or for
each constituent present in an amount of more than 1% by dry mass)
must be converted to carbon dioxide by the end of the test period
when compared to the control or in absolute. According to European
standard ED 13432 (2000), a material must exhibit a biodegradation
of at least 90 percent in total, or a biodegradation of at least 90
percent of the maximum degradation of a suitable reference material
after a plateau has been reached for both the reference and test
item. The maximum test duration for biodegradability under
industrial compositing conditions is 180 days. The CA staple fibers
described herein may exhibit a biodegradation of at least 90
percent within not more than 180 days, measured according 14855-1
(2012) under industrial composting conditions. In some cases, the
CA staple fibers may exhibit a biodegradation of at least about 91,
or at least 92, or at least 93, or at least 94, or at least 95, or
at least 96, or at least 97, or at least 98, or at least 99, or at
least 99.5 percent within not more than 180 days, or the fibers may
exhibit 100 percent biodegradation within not more than 180 days,
measured according 14855-1 (2012) under industrial composting
conditions.
[0119] Additionally, or in the alternative, CA staple fibers
described herein may exhibit a biodegradation of least 90 percent
within not more than about 175, or not more than 170, or not more
than 165, or not more than 160, or not more than 155, or not more
than 150, or not more than 145, or not more than 140, or not more
than 135, or not more than 130, or not more than 125, or not more
than 120, or not more than 115, or not more than 110, or not more
than 105, or not more than 100, or not more than 95, or not more
than 90, or not more than 85, or not more than 80, or not more than
75, or not more than 70, or not more than 65, or not more than 60,
or not more than 55, or not more than 50, or not more than 45 days,
measured according 14855-1 (2012) under industrial composting
conditions. In some cases, the CA staple fibers can be at least
about 97, 98, 99, or 99.5 percent biodegradable within not more
than about 65, or not more than 60, or not more than 55, or not
more than 50, or not more than 45 days of testing according to ISO
14855-1 (2012) under industrial composting conditions. As a result,
the CA staple fibers described herein may be considered
biodegradable according ASTM D6400 and ISO 17088 when tested under
industrial composting conditions.
[0120] The fibers or fibrous articles of the present invention may
exhibit a biodegradation in soil of at least 60 percent within not
more than 130 days, measured according to ISO 17556 (2012) under
aerobic conditions at ambient temperature. In some cases, the
fibers can exhibit a biodegradation of at least 60 percent in a
period of not more than 130, or not more than 120, or not more than
110, or not more than 100, or not more than 90, or not more than
80, or not more than 75 days when tested under these conditions,
also called "soil composting conditions." These may not be aqueous
or anaerobic conditions. In some cases, the fibers can exhibit a
total biodegradation of at least about 65, or at least 70, or at
least 72, or at least 75, or at least 77, or at least 80, or at
least 82, or at least 85 percent, when tested under according to
ISO 17556 (2012) for a period of 195 days under soil composting
conditions. This may represent a relative biodegradation of at
least about 70, or at least 75, or at least 80, or at least 85, or
at least 90, or at least 95 percent, when compared to cellulose
fibers subjected to identical test conditions.
[0121] In order to be considered "biodegradable," under soil
composting conditions according the OK biodegradable SOIL
conformity mark of Vingotte and the DIN Gepruft Biodegradable in
soil certification scheme of DIN CERTCO, a material must exhibit a
biodegradation of at least 90 percent in total (e.g., as compared
to the initial sample), or a biodegradation of at least 90 percent
of the maximum degradation of a suitable reference material after a
plateau has been reached for both the reference and test item. The
maximum test duration for biodegradability under soil compositing
conditions is 2 years. The CA staple fibers as described herein may
exhibit a biodegradation of at least 90 percent within not more
than 2 years, 1.75 years, 1 year, 9 months, or 6 months measured
according ISO 17556 (2012) under soil composting conditions. In
some cases, the CA staple fibers may exhibit a biodegradation of at
least about 91, or at least 92, or at least 93, or at least 94, or
at least 95, or at least 96, or at least 97, or at least 98, or at
least 99, or at least 99.5 percent within not more than 2 years, or
the fibers may exhibit 100 percent biodegradation within not more
than 2 years, measured according ISO 17556 (2012) under soil
composting conditions.
[0122] Additionally, or in the alternative, CA staple fibers
described herein may exhibit a biodegradation of at least 90
percent within not more than about 700, 650, 600, 550, 500, 450,
400, 350, 300, 275, 250, 240, 230, 220, 210, 200, or 195 days,
measured according 17556 (2012) under soil composting conditions.
In some cases, the CA staple fibers can be at least about 97, or at
least 98, or at least 99, or at least 99.5 percent biodegradable
within not more than about 225, or not more than 220, or not more
than 215, or not more than 210, or not more than 205, or not more
than 200, or not more than 195 days of testing according to ISO
17556 (2012) under soil composting conditions. As a result, the CA
staple fibers described herein may meet the requirements to receive
The OK biodegradable SOIL conformity mark of Vingotte and to meet
the standards of the DIN Geprft Biodegradable in soil certification
scheme of DIN CERTCO.
[0123] In some cases, CA staple fibers (or fibrous articles) of the
present invention may include less than 1, or not more than 0.75,
or not more than 0.50, or not more than 0.25 weight percent of
components of unknown biodegradability, based on the weight of the
CA staple fiber. In some cases, the fibers or fibrous articles
described herein may include no components of unknown
biodegradability.
[0124] In addition to being biodegradable under industrial and/or
home composting conditions, CA staple fibers or fibrous articles as
described herein may also be compostable under home and/or
industrial conditions. As described previously, a material is
considered compostable if it meets or exceeds the requirements set
forth in EN 13432 for biodegradability, ability to disintegrate,
heavy metal content, and ecotoxicity. The CA staple fibers or
fibrous articles described herein may exhibit sufficient
compostability under home and/or industrial composting conditions
to meet the requirements to receive the OK compost and OK compost
HOME conformity marks from Vingotte.
[0125] In some cases, the CA staple and fibers and fibrous articles
described herein may have a volatile solids concentration, heavy
metals and fluorine content that fulfill all of the requirements
laid out by EN 13432 (2000). Additionally, the CA staple fibers may
not cause a negative effect on compost quality (including chemical
parameters and ecotoxicity tests).
[0126] In some cases, the CA staple fibers or fibrous articles can
exhibit a disintegration of at least 90 percent within not more
than 26 weeks, measured according to ISO 16929 (2013) under
industrial composting conditions. In some cases, the fibers or
fibrous articles may exhibit a disintegration of at least about 91,
or at least 92, or at least 93, or at least 94, or at least 95, or
at least 96, or at least 97, or at least 98, or at least 99, or at
least 99.5 percent under industrial composting conditions within
not more than 26 weeks, or the fibers or articles may be 100
percent disintegrated under industrial composting conditions within
not more than 26 weeks. Alternatively, or in addition, the fibers
or articles may exhibit a disintegration of at least 90 percent
under industrial compositing conditions within not more than about
26, or not more than 25, or not more than 24, or not more than 23,
or not more than 22, or not more than 21, or not more than 20, or
not more than 19, or not more than 18, or not more than 17, or not
more than 16, or not more than 15, or not more than 14, or not more
than 13, or not more than 12, or not more than 11, or not more than
10 weeks, measured according to ISO 16929 (2013). In some cases,
the CA staple fibers or fibrous articles described herein may be at
least 97, or at least 98, or at least 99, or at least 99.5 percent
disintegrated within not more than 12, or not more than 11, or not
more than 10, or not more than 9, or not more than 8 weeks under
industrial composting conditions, measured according to ISO 16929
(2013).
[0127] In some cases, the CA staple fibers or fibrous articles can
exhibit a disintegration of at least 90 percent within not more
than 26 weeks, measured according to ISO 16929 (2013) under home
composting conditions. In some cases, the fibers or fibrous
articles may exhibit a disintegration of at least about 91, or at
least 92, or at least 93, or at least 94, or at least 95, or at
least 96, or at least 97, or at least 98, or at least 99, or at
least 99.5 percent under home composting conditions within not more
than 26 weeks, or the fibers or articles may be 100 percent
disintegrated under home composting conditions within not more than
26 weeks. Alternatively, or in addition, the fibers or articles may
exhibit a disintegration of at least 90 percent within not more
than about 26, or not more than 25, or not more than 24, or not
more than 23, or not more than 22, or not more than 21, or not more
than 20, or not more than 19, or not more than 18, or not more than
17, or not more than 16, or not more than 15 weeks under home
composting conditions, measured according to ISO 16929 (2013). In
some cases, the CA staple fibers or fibrous articles described
herein may be at least 97, or at least 98, or at least 99, or at
least 99.5 percent disintegrated within not more than 20, or not
more than 19, or not more than 18, or not more than 17, or not more
than 16, or not more than 15, or not more than 14, or not more than
13, or not more than 12 weeks, measured under home composting
conditions according to ISO 16929 (2013).
[0128] CA staple fibers of the present invention can achieve higher
levels of biodegradability and/or compostability without use of
additives that have traditionally been used to facilitate
environmental non-persistence of similar fibers. Such additives can
include, for example, photodegradation agents, biodegradation
agents, decomposition accelerating agents, and various types of
other additives. Despite being substantially free of these types of
additives, the CA staple fibers and articles have unexpectedly been
found to exhibit enhanced biodegradability and compostability when
tested under industrial, home, and/or soil conditions, as discussed
previously.
[0129] In some embodiments, the CA staple fibers described herein
may be substantially free of photodegradation agents. For example,
the fibers may include not more than about 1, or not more than
0.75, or not more than 0.50, or not more than 0.25, or not more
than 0.10, or not more than 0.05, or not more than 0.025, or not
more than 0.01, or not more than 0.005, or not more than 0.0025, or
not more than 0.001 weight percent of photodegradation agent, based
on the total weight of the fiber, or the fibers may include no
photodegradation agents. Examples of such photodegradation agents
include, but are not limited to, pigments which act as
photooxidation catalysts and are optionally augmented by the
presence of one or more metal salts, oxidizable promoters, and
combinations thereof. Pigments can include coated or uncoated
anatase or rutile titanium dioxide, which may be present alone or
in combination with one or more of the augmenting components such
as, for example, various types of metals. Other examples of
photodegradation agents include benzoins, benzoin alkyl ethers,
benzophenone and its derivatives, acetophenone and its derivatives,
quinones, thioxanthones, phthalocyanine and other photosensitizers,
ethylene-carbon monoxide copolymer, aromatic ketone-metal salt
sensitizers, and combinations thereof.
[0130] In some embodiments, the CA staple fibers described herein
may be substantially free of biodegradation agents and/or
decomposition agents. For example, the fibers may include not more
than about 1, or not more than 0.75, or not more than 0.50, or not
more than 0.25, or not more than 0.10, or not more than 0.05, or
not more than 0.025, or not more than 0.01, or not more than 0.005,
or not more than 0.0025, or not more than 0.0020, or not more than
0.0015, or not more than 0.001, or not more than 0.0005 weight
percent of biodegradation agents and/or decomposition agents, based
on the total weight of the fiber, or the fibers may include no
biodegradation and/or decomposition agents. Examples of such
biodegradation and decomposition agents include, but are not
limited to, salts of oxygen acid of phosphorus, esters of oxygen
acid of phosphorus or salts thereof, carbonic acids or salts
thereof, oxygen acids of phosphorus, oxygen acids of sulfur, oxygen
acids of nitrogen, partial esters or hydrogen salts of these oxygen
acids, carbonic acid and its hydrogen salt, sulfonic acids, and
carboxylic acids.
[0131] Other examples of such biodegradation and decomposition
agents include an organic acid selected from the group consisting
of oxo acids having 2 to 6 carbon atoms per molecule, saturated
dicarboxylic acids having 2 to 6 carbon atoms per molecule, and
lower alkyl esters of said oxo acids or said saturated dicarboxylic
acids with alcohols having from 1 to 4 carbon atoms. Biodegradation
agents may also comprise enzymes such as, for example, a lipase, a
cellulase, an esterase, and combinations thereof. Other types of
biodegradation and decomposition agents can include cellulose
phosphate, starch phosphate, calcium secondary phosphate, calcium
tertiary phosphate, calcium phosphate hydroxide, glycolic acid,
lactic acid, citric acid, tartaric acid, malic acid, oxalic acid,
malonic acid, succinic acid, succinic anhydride, glutaric acid,
acetic acid, and combinations thereof.
[0132] CA staple fibers of the present invention may also be
substantially free of several other types of additives that have
been added to other fibers to encourage environmental
non-persistence. Examples of these additives can include, but are
not limited to, polyesters, including aliphatic and low molecular
weight (e.g., less than 5000) polyesters, enzymes, microorganisms,
water soluble polymers, modified cellulose acetate,
water-dispersible additives, nitrogen-containing compounds,
hydroxy-functional compounds, oxygen-containing heterocyclic
compounds, sulfur-containing heterocyclic compounds, anhydrides,
monoepoxides, and combinations thereof. In some cases, the fibers
described herein may include not more than about 0.5, or not more
than 0.4, or not more than 0.3, or not more than 0.25, or not more
than 0.1, or not more than 0.075, or not more than 0.05, or not
more than 0.025, or not more than 0.01, or not more than 0.0075, or
not more than 0.005, or not more than 0.0025, or not more than
0.001 weight percent of these types of additives, or the CA staple
fibers may not include any of these types of additives.
[0133] The following examples are given to illustrate the invention
and to enable any person skilled in the art to make and use the
invention. It should be understood, however, that the invention is
not to be limited to the specific conditions or details described
in these examples. The patentable scope of the invention is defined
by the claims, and may include other examples that occur to those
skilled in the art.
EXAMPLES
Example 1
[0134] The feasibility of successfully making a 100% cellulose
acetate spun yarn from low denier, high CPI, round CA staple fibers
was explored. A successful trial of making a sliver and spun yarn
from 100% CA staple fiber is predictive of the influence such
fibers would have in a blended sliver.
[0135] CA staple fiber tow bundles were produced having a round
cross section of 1.8 denier fiber, 17CPI, and coated with Pulcra
Stantex 2098 finish in an amount of 0.5% FOY. A 100 pound sample of
the tow bundle was collected and cut to a 38 mm stretched staple
length with 0.5% FOY PM lubricant commercialized by Eastman as PM
30419 added just prior to cutting. The yarn spinning conditions
were maintained at .about.55% humidity during the experiment. The
staple fibers were subjected to carding, drawing, roving, and ring
spinning.
[0136] For an initial proof of concept, the staple fibers
successfully spun into six 2 pound packages of 20 singles
(.about.250 denier) yarn at 4.2 twist multiple. However, this
resulting yarn had a low tenacity of 0.7 g/den and low elongation
of about 11% measured according to ASTM D-2256 method. The low
tenacity and elongation numbers are a reflection of low cohesion
between the staple fibers which causes them to easily slide past
each other upon stretching the yarn. Additionally, the higher twist
multiple of 4.2 (typical twist multiple for a knitting yarn is
3.5-3.9) had to be employed to overcome the low cohesion between
the fibers since the initial target of a 30 singles (.about.150
denier) with a 3.5 twist multiplier was too weak to successfully
spin into yarn.
Example 2
[0137] In this example, the effect of CPI, shape, and finishes on
the staple fiber's carding and spinning performance were evaluated.
The variables explored were 8, 12 and 18 CPI, while the fiber
shapes explored were round and trilobal and the two secondary spin
finishes compared were PM 30149 and Pulcra Tow (E8-0.5%), and
Stantex H1385 available from Pulcra, as summarized in Table 1. The
primary spin finish was applied to the fibers after extrusion,
prior to crimping, and the secondary spin finish was applied to the
tow band prior to cutting. The amount of primary and secondary
finishes is set forth in Table 1. The staple fibers had a cut
length of 38 mm and a denier of 1.8.
TABLE-US-00001 TABLE 1 Crimp Cross Primary Spin Secondary Spin
Level (cpi) Section Finish Finish Sample 1 8 Trilobal Tow (E8 -
0.5%) AY23 Sample 2 12 Trilobal Tow (E4.7 - 0.5%) AY23 Sample 3 18
Round Pulcra (Stantex AY23 2098 0.65%) Sample 4 18 Trilobal Pulcra
(Stantex AY23 2098 0.65%)) Sample 5 18 Trilobal Pulcra (Stantex
Stantex H1385 2098 0.65%)) Sample 6 18 Round Pulcra (Stantex
Stantex H1385 2098 0.65%)) Sample 7 12 Trilobal Tow (E4.7 - 0.5%)
Stantex H1385
[0138] The samples were all subjected to a carding operation,
however, only samples 3 and 6 were successfully converted into a
carded sliver, drawn and converted into roving and finally spun
into a yarn.
[0139] Samples 3 and 4 had the same CPI and finish. Samples 5 and 6
also had the same CPI and finish. However, only the round samples 3
and 6 could be successfully spun into yarns. Surprisingly, none of
the samples with a trilobal cross section could be successfully
carded to a viable sliver as determined by failure to produce a
card sliver with sufficient cohesion and static properties.
Example 3
[0140] This example demonstrates the successful spinning of a yarn
using the CA staple fibers of the invention alone and blended with
other fiber materials.
[0141] The CA staple fibers and all other synthetic staple fibers
had a denier of about 1.5 and cut to a 38 mm staple length. For
cotton, upland cotton was used. The synthetic fibers were blended
intimately while the acetate/cotton blending was done on a draw
frame.
[0142] For the 100% acetate spun yarns, a round 1.65 DPF bright tow
(no TiO2), 16 CPI fiber tow band was made with a 0.7% AY23 as the
primary spin finish. The fibers from this tow band were used to
make the samples set forth in Table 2 to produce 29/1 spun yarns.
The tow sample was cut using either AY23 or Lurol 7414K as the
secondary spin finish targeting 1.5% each respectively. The cut
length of the staple fibers were 38 mm. The break factor was
determined by the count strength product as a function of skein
strength and yarn count and according to ASTM D1576.
[0143] ASTM 1576 determines the breaking strength of yarn in skein
form which is converted to a skein break factor (count strength
product) dependent on yarn count, while ASTM 2256 provides the
breaking strength and elongation using a single strand method. The
skein method is useful for spun yarns because it provides an
average across multiple strands in the skein thereby overcoming the
inherent non-uniformity of spun yarns. ASTM 1576 is rarely, if
ever, used for filament yarns because the uniformity of filament
yarns makes it possible to obtain reliable results economically by
the single-strand method (ASTM 2256).
[0144] For 100% cellulose acetate containing spun yarns, the skein
break factor (count strength product) should be equal to or greater
than 1100.
TABLE-US-00002 TABLE 2 Yarn Composition Yarn Denier Break Sample
(%) Size Equivalent Factor.sup.1 Acetate Filament 100 35/1 150 1800
Acetate (AY23) 100 29/1 183 1137 Acetate (Lurol 100 29/1 183 1181
74414K) Polyester 100 29/1 183 2825 Nylon 100 29/1 183 2795 Cotton
100 29/1 183 2368 Acetate/Polyester 50/50 29/1 183 1767
Acetate/Nylon 50/50 29/1 183 1739 Acetate/Cotton 46.5/53.5 29/1 183
1447 .sup.1Break factor measured on skeins and is not typically
done for filament yarns but done for illustrative purposes to show
the difference in relative strengths of spun yarns relative to 150
denier filament acetate which is accepted as a weak yarn. The
relative strengths of the 100% synthetic yarns were consistent with
the range expected for industry standards.
[0145] Both samples of CA staple fibers were taken to sliver and
successfully spun to a yarn. Both samples were taken to sliver. CA
staple fiber samples containing Lurol 7414K finish were used as the
CA staple fiber for blending with other fiber materials.
[0146] The synthetic blend yarns (acetate/nylon and
acetate/polyester) were made by intimately blending 50/50 weight
ratios of both fibers by weight in the hopper prior to the fine
opener. No issues were observed during carding, drawing, roving or
spinning. The specific density needed to be taken into
consideration as the specific densities affected the sliver weights
and adjustments needed to be made to hit the targeted sliver
weights. The final yarns were targeted at 29/1 based on the best
balance obtained using the acetate Lurol 7414K sample as the
standard to match. In order to reach a 29/1 of acceptable break
factor (1181) a twist multiple of 3.8 was used based on results
from a twist curve where the strength to twist multiple were
optimized to balance liveliness (knittability and hand in final
fabric) with strength. All the yarn properties were determined
according to ASTM 2256. Table 3 summarize the yarn properties.
TABLE-US-00003 TABLE 3 Time to B-Force Elongation Tenacity B-Work
Mod 2% Sample Break(s) (gF) (%) (gF/den) (gF cm) (N/tex) Acetate
0.79 164.0 13.06 0.91 778.6 1.181 Acetate 1 0.81 160.3 13.49 0.89
790.1 1.521 Polyester 1.09 329.7 18.12 1.83 1678 1.089 Nylon 1.34
379.9 22.10 2.11 1935 0.606 Cotton 0.41 312.9 6.89 1.74 538.8 1.463
Acetate/ 1.11 250.1 18.47 1.39 1428 1.612 Polyester Acetate/ 1.06
233.6 17.60 1.30 1176 0.849 Nylon Acetate/ 0.35 186.6 5.79 1.04
313.6 1.514 Cotton
Example 4
[0147] This example evaluates the utility of a variety of finishes
on the F/F CODF and F/M CODF as well as the effectiveness of static
electricity build up on continuous filaments, which would have
similar values upon being cut into staple fibers.
[0148] Uncrimped CA continuous fibers were produced on a
pilot-scale single tow cabinet and wound on a yarn tube. The yarn
total denier was 1600 g/9000 m and the dpf was 1.80. The amount of
finish is set forth in Table 4 below, and the finish was applied at
an emulsion level of 2%. No other finish lubricant was applied
other than the finish described in Table 4. The yarn packages were
conditioned at 70.degree. F..+-.2F and 65%.+-.4% relative humidity
for 24 hours before testing. F/M CODF was measured according to
ASTM D3108/D3108M-13 at 100 m/min and an input tension of 10 grams
on a Constant Tension Transport with Electronic Drive (CTT-E)
instrument set up according FIG. 2 in the ASTM D3412/3412M-13
procedure. F/F CODF was measured according to ASTM D3412/3412M-13,
with the exception that only 1 twist could be used rather than 3
twists due to the strength of the fiber and that it was performed
at 20 m/min rather than 0.2 m/min due to equipment constraints. The
yarn was tested on a CTT-E set up according to FIG. 1 in the ASTM
procedure and had an input tension of 10 grams.
[0149] Static electricity was measured as follows: for each
package, a 2 foot section of yarn was secured at one end, the fiber
was then rubbed with a pencil along the full length three times
back and forth, and the resulting electric field was measured using
a model FMX-003 Simco Electrostatic Fieldmeter. The measurements
were taken at ambient conditions.
TABLE-US-00004 TABLE 4 Package % Static # Finish Level FOY F/M F/F
(kV) 65 Lurol 6511 HIGH 0.18 0.4816 0.1 0 68 Lurol 6511 HIGH 0.18
0.4718 0.098 0.06 73 Lurol 6511 HIGH 0.18 0.4779 0.1009 -0.02 76
Lurol 6511 HIGH 0.18 0.4658 0.099 0.01 71 Lurol 6511 HIGH 0.18
0.4718 0.0975 0 66 Lurol 6511 LOW 0.13 0.4673 0.0971 -0.01 75 Lurol
6511 LOW 0.13 0.4572 0.0931 0.03 74 Lurol 6511 LOW 0.13 0.4565
0.0979 0.02 80 Lurol 6511 LOW 0.13 0.4549 0.0966 0.01 78 Lurol 6511
LOW 0.13 0.4576 0.0841 0.06 79 Lurol 6511 LOW 0.13 0.4561 0.0895
0.02 70 Lurol 6511 MEDIUM 0.15 0.4665 0.0978 0 77 Lurol 6511 MEDIUM
0.15 0.4808 0.1012 0.03 72 Lurol 6511 MEDIUM 0.15 0.4629 0.103
-0.01 69 Lurol 6511 MEDIUM 0.15 0.4675 0.0988 -0.01 67 Lurol 6511
MEDIUM 0.15 0.4626 0.0986 0 53 Lurol 7414K LOW 0.04 0.5326 0.2202
1.03 59 Lurol 7414K LOW 0.04 0.5365 0.2083 0.27 63 Lurol 7414K LOW
0.04 0.5321 0.2151 1.04 56 Lurol 7414K LOW 0.04 0.5365 0.2111 0.8
58 Lurol 7414K LOW 0.04 0.5489 0.2021 1.02 61 Lurol 7414K LOW 0.04
0.5859 0.2174 1.26 60 Lurol 7414K HIGH 0.64 0.4512 0.1289 0.97 62
Lurol 7414K HIGH 0.64 0.451 0.1289 0.49 51 Lurol 7414K HIGH 0.64
0.4739 0.1637 0.68 54 Lurol 7414K HIGH 0.64 0.4585 0.1087 1.04 50
Lurol 7414K HIGH 0.64 0.5038 0.1231 0.31 49 Lurol 7414K MEDIUM 0.28
0.5207 0.2143 1.2 57 Lurol 7414K MEDIUM 0.28 0.5145 0.2111 0.53 55
Lurol 7414K MEDIUM 0.28 0.5236 0.2004 0.96 64 Lurol 7414K MEDIUM
0.28 0.5072 0.2075 0.78 52 Lurol 7414K MEDIUM 0.28 0.5363 0.1985
0.63 45 Lurol 912T LOW 0.26 0.5561 0.224 0.98 35 Lurol 912T LOW
0.26 0.5484 0.2305 0.9 40 Lurol 912T LOW 0.26 0.6344 0.2211 1.18 37
Lurol 912T LOW 0.26 0.6501 0.221 1.14 34 Lurol 912T LOW 0.26 0.6241
0.2162 0.68 39 Lurol 912T MEDIUM 0.34 0.5999 0.2069 0.49 47 Lurol
912T MEDIUM 0.34 0.6025 0.2152 0.62 48 Lurol 912T MEDIUM 0.34
0.6047 0.1955 0.96 42 Lurol 912T MEDIUM 0.34 0.6144 0.2067 0.55 36
Lurol 912T MEDIUM 0.34 0.6377 0.2021 0.73 33 Lurol 912T MEDIUM 0.34
0.6244 0.2018 0.97 38 Lurol 912T HIGH 0.29 0.5982 0.2209 0.8 43
Lurol 912T HIGH 0.29 0.6105 0.1993 0.87 46 Lurol 912T HIGH 0.29
0.6174 0.1969 0.8 44 Lurol 912T HIGH 0.29 0.6084 0.205 0.71 41
Lurol 912T HIGH 0.29 0.6299 0.1955 0.41 17 Stantex 2098 LOW 0.11
0.2116 0.58 24 Stantex 2098 LOW 0.11 0.5991 0.2153 0.56 27 Stantex
2098 LOW 0.11 0.6155 0.2074 0.47 20 Stantex 2098 LOW 0.11 0.574
0.2136 1.08 22 Stantex 2098 LOW 0.11 0.6055 0.2151 0.8 28 Stantex
2098 MEDIUM 0.31 0.5873 0.2135 0.67 18 Stantex 2098 MEDIUM 0.31
0.5164 0.2137 1.3 32 Stantex 2098 MEDIUM 0.31 0.5502 0.2066 0.9 26
Stantex 2098 MEDIUM 0.31 0.5756 0.2164 0.95 19 Stantex 2098 MEDIUM
0.31 0.6093 0.2035 0.89 23 Stantex 2098 HIGH 0.69 0.499 0.1741 0.7
21 Stantex 2098 HIGH 0.69 0.5146 0.1917 1.15 25 Stantex 2098 HIGH
0.69 0.5225 0.1759 0.75 30 Stantex 2098 HIGH 0.69 0.5269 0.1862
0.66 29 Stantex 2098 HIGH 0.69 0.5312 0.2143 1.02 31 Stantex 2098
HIGH 0.69 0.5532 0.1957 0.85 9 Stantex 7638-A LOW 0.29 0.6672
0.2094 0.62 6 Stantex 7638-A LOW 0.29 0.5991 0.2095 0.82 5 Stantex
7638-A LOW 0.29 0.5893 0.2057 0.73 7 Stantex 7638-A LOW 0.29 0.6264
0.2106 0.48 8 Stantex 7638-A LOW 0.29 0.6106 0.1994 1.05 1 Stantex
7638-A MEDIUM 0.25 0.6135 0.2068 0.61 15 Stantex 7638-A MEDIUM 0.25
0.5959 0.1913 0.82 16 Stantex 7638-A MEDIUM 0.25 0.6156 0.189 0.49
4 Stantex 7638-A MEDIUM 0.25 0.6144 0.19 0.2 14 Stantex 7638-A
MEDIUM 0.25 0.6449 0.201 0.82 2 Stantex 7638-A HIGH 0.39 0.5839
0.1709 0.73 3 Stantex 7638-A HIGH 0.39 0.595 0.2051 1.8 11 Stantex
7638-A HIGH 0.39 0.5337 0.1889 0.21 10 Stantex 7638-A HIGH 0.39
0.6048 0.1868 1.03 13 Stantex 7638-A HIGH 0.39 0.6281 0.2001 0.65
12 Stantex 7638-A HIGH 0.39 0.6261 0.1989 1.33 6 Lurol PS-15602 LOW
0.19 0.6136 0.2228 1.08 10 Lurol PS-15602 LOW 0.19 0.6256 0.2254
0.95 12 Lurol PS-15602 LOW 0.19 0.6005 0.2123 0.58 8 Lurol PS-15602
LOW 0.19 0.5881 0.2341 0.68 1 Lurol PS-15602 LOW 0.19 0.573 0.2088
0.35 9 Lurol PS-15602 LOW 0.19 0.6022 0.2174 0.96 5 Lurol PS-15602
MEDIUM 0.29 0.6113 0.2066 0.62 3 Lurol PS-15602 MEDIUM 0.29 0.6009
0.2188 0.89 15 Lurol PS-15602 MEDIUM 0.29 0.5991 0.2163 0.73 2
Lurol PS-15602 MEDIUM 0.29 0.5909 0.2094 0.84 4 Lurol PS-15602
MEDIUM 0.29 0.5985 0.2087 0.61 13 Lurol PS-15602 HIGH 0.47 0.5968
0.2154 0.37 16 Lurol PS-15602 HIGH 0.47 0.5951 0.205 0.68 7 Lurol
PS-15602 HIGH 0.47 0.5903 0.191 1.2 11 Lurol PS-15602 HIGH 0.47
0.5914 0.2061 0.7 14 Lurol PS-15602 HIGH 0.47 0.6037 0.21 1.15 22
Tallopol SE 90 LOW 0.18 0.6056 0.2253 0.75 30 Tallopol SE 90 LOW
0.18 0.6003 0.2282 0.68 31 Tallopol SE 90 LOW 0.18 0.594 0.2117
0.84 23 Tallopol SE 90 LOW 0.18 0.5802 0.2339 0.78 17 Tallopol SE
90 LOW 0.18 0.5911 0.2251 0.78 20 Tallopol SE 90 MEDIUM 0.34 0.554
0.2167 0.66 18 Tallopol SE 90 MEDIUM 0.34 0.5652 0.2264 0.62 19
Tallopol SE 90 MEDIUM 0.34 0.5819 0.226 0.83 32 Tallopol SE 90
MEDIUM 0.34 0.6135 0.2314 0.5 24 Tallopol SE 90 MEDIUM 0.34 0.5666
0.226 0.28 21 Tallopol SE 90 MEDIUM 0.34 0.579 0.2232 0.4 28
Tallopol SE 90 HIGH 0.4 0.6551 0.2251 0.47 25 Tallopol SE 90 HIGH
0.4 0.6807 0.2275 0.78 26 Tallopol SE 90 HIGH 0.4 0.61 0.2211 0.89
27 Tallopol SE 90 HIGH 0.4 0.5867 0.2173 0.44 29 Tallopol SE 90
HIGH 0.4 0.5842 0.2317 0.47
[0150] Lurol 6511 had the lowest CODF for both F/M and F/F as well
as the lowest static charge-approximately zero. Lurol 7414K had
downward trends for both F/M and F/F, but F/F was steeper. Other
lubricants were generally flat and comparable to one another,
though Stantex 2098 did show slight downward trends. All the spin
finishes, aside from Lurol 6511 were not statistically
significantly different from one another in regards to controlling
static.
[0151] As used herein, the terms "comprising," "comprises," and
"comprise" are open-ended transition terms used to transition from
a subject recited before the term to one or more elements recited
after the term, where the element or elements listed after the
transition term are not necessarily the only elements that make up
the subject.
[0152] As used herein, the terms "including," "includes," and
"include" have the same open-ended meaning as "comprising,"
"comprises," and "comprise."
[0153] As used herein, the terms "having," "has," and "have" have
the same open-ended meaning as "comprising," "comprises," and
"comprise."
[0154] As used herein, the terms "containing," "contains," and
"contain" have the same open-ended meaning as "comprising,"
"comprises," and "comprise."
[0155] As used herein, the terms "a," "an," "the," and "said" mean
one or more.
[0156] As used herein, the term "and/or," when used in a list of
two or more items, means that any one of the listed items can be
employed by itself or any combination of two or more of the listed
items can be employed. For example, if a composition is described
as containing components A, B, and/or C, the composition can
contain A alone; B alone; C alone; A and B in combination; A and C
in combination; B and C in combination; or A, B, and C in
combination.
[0157] The preferred forms of the invention described above are to
be used as illustration only, and should not be used in a limiting
sense to interpret the scope of the present invention.
* * * * *