U.S. patent application number 10/135888 was filed with the patent office on 2003-10-30 for tacky polymer melt spinning process.
Invention is credited to Knorr, Raymond S., Miller, Richard W., Nunning, Walter J..
Application Number | 20030201567 10/135888 |
Document ID | / |
Family ID | 29249559 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030201567 |
Kind Code |
A1 |
Miller, Richard W. ; et
al. |
October 30, 2003 |
Tacky polymer melt spinning process
Abstract
A method for high speed melt spinning of binder fibers by
melting a polymer that exhibits substantially no exothermic
crystallization peak as measured by DSC when it is cooled to
solidification from a molten state according to test A, spinning
said polymer at a speed of greater than about 2000 meters per
minute to form said binder fibers; and winding said binder fiber
onto a spin bobbin.
Inventors: |
Miller, Richard W.;
(Pensacola, FL) ; Nunning, Walter J.; (Pensacola,
FL) ; Knorr, Raymond S.; (Pensacola Beach,
FL) |
Correspondence
Address: |
Craig M. Lundell
HOWREY SIMON ARNOLD & WHITE, LLP
P.O. Box 4433
Houston
TX
77210-4433
US
|
Family ID: |
29249559 |
Appl. No.: |
10/135888 |
Filed: |
April 30, 2002 |
Current U.S.
Class: |
264/211.14 ;
264/130; 264/211.12 |
Current CPC
Class: |
D01F 6/80 20130101; D01F
6/60 20130101 |
Class at
Publication: |
264/211.14 ;
264/211.12; 264/130 |
International
Class: |
D01D 005/08; D01F
006/60 |
Claims
What is claimed is:
1. A method for high speed melt spinning of binder fiber
comprising; melting a polymer having a melting temperature range of
greater than 0.degree. C. to 160.degree. C.; spinning said polymer
at a speed of greater than about 2000 meters per minute to form
said binder fiber; and winding said binder fiber onto a spin
bobbin.
2. A method according to claim 1, wherein said polymer comprises
polyamides.
3. A method according to claim 1, wherein said polymer comprises
nylon 6/66/612 and 6/69.
4. A method according to claim 1, wherein said polymer comprises
nylon 6/66/12.
5. A method according to claim 1, wherein said melting temperature
range is greater than 0.degree. C. to less than about 150.degree.
C.
6. A method according to claim 1, wherein said melting temperature
range is greater than 0.degree. C. to less than about 140.degree.
C.
7. A method according to claim 1, wherein said speed is greater
than about 2500 meters per minute.
8. A method according to claim 1, wherein said speed is greater
than about 3000 meters per minute.
9. A method according to claim 1, wherein spin finish is placed on
said binder fiber prior to said winding.
10. A method according to claim 1, wherein unwinding tension of
said binder fiber from said spin bobbin is less than 2.0 grams on
average.
11. A method according to claim 1, wherein unwinding tension of
said binder fiber from said spin bobbin is less than 1.5 grams on
average.
12. A method according to claim 1, wherein unwinding tension of
said binder fiber from said spin bobbin is less than 1.0 grams on
average.
13. A method according to claim 1, wherein said winding of said
fiber comprises a speed substantially equal to said spinning
speed.
14. A method according to claim 1, wherein said polymer exhibits
substantially no exothermic crystallization peak as measured by DSC
when it is cooled to solidification from a molten state by test
A.
15. A method for high speed melt spinning of binder fibers
comprising; melting a polymer that exhibits substantially no
exothermic crystallization peak as measured by DSC when it is
cooled to solidification from a molten state according to test A;
spinning said polymer at a speed of greater than about 2000 meters
per minute to form said binder fiber; and winding said binder fiber
onto a spin bobbin.
16. A method according to claim 15, wherein said polymer comprises
polyamides.
17. A method according to claim 15, wherein said polymer comprises
nylon 6/66/612 and 6/69.
18. A method according to claim 15, wherein said polymer comprises
nylon 6/66/12.
19. A method according to claim 15, wherein said speed is greater
than about 2500 meters per minute.
20. A method according to claim 15, wherein said speed is greater
than about 3000 meters per minute.
21. A fiber made by the method of claim 15.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a binder fiber
and a method of making such binder fiber. The present invention
also relates to the use of such binder fiber in yarns and textile
materials.
BACKGROUND
[0002] It is known that binder fibers may be blended with base or
non-adhesive fibers to form a yarn or textile material and then the
binder fiber may be melted, thereby adhering the base fibers
together. See U.S. Pat. Nos. 2,880,112, 2,252,999, 3,877,214,
3,494,819 and 5,284,009, the entire subject matter of which is
incorporated herein by reference. Typically, the binder fiber melts
at temperatures sufficiently less than those at which the base
fibers melt or begin softening, thereby allowing the base fibers to
retain their physical properties while at the same time imparting
the yarn or textile material with significantly improved properties
(e.g., wearability, initial appearance, etc.).
[0003] Selection of binder fiber materials is important with regard
to achieving improved properties in the resulting yarn or textile
materials. Certain physical and chemical characteristics of binder
materials are desirable, such as ability to adhere to the base
fiber, ability to flow between base fibers under standard process
conditions and/or ability to be unwound at high speeds (i.e.,
greater than 1,000 mpm). For example, U.S. Pat. No. 4,258,094, the
entire subject matter of which is incorporated herein for
reference, describes the use of an ethylene-vinyl acetate binder
fiber with a base fiber to form melt bonded fabrics. U.S. Pat. No.
5,478,624, the entire subject matter of which in incorporated
herein by reference, sets forth a synthetic yarn prepared from a
blend of base fiber combined with a polyamide copolymer binder
fiber. The yarn is utilized in a carpet and is heated to bond the
base fibers together. U.S. Pat. No. 5,712,209, the entire subject
matter of which is incorporated herein by reference, describes the
use of polyethylene fibers as binder fibers in combination with
base fibers that melt at temperatures above the melting ranges of
the polyethylene fibers. The polyethylene fibers are melted to
"lock" the base fibers in place, thereby producing a "dimensionally
stable" structure.
[0004] Because binder fibers desirably melt at temperature ranges
below those of base fibers, the binder material typically is
limited to polymers having low melting temperature ranges (e.g.,
below about 200.degree. C.). Many of these polymers possess a low
propensity to crystallize (i.e., to form the stable inter- and
intra-molecular associations with some degree of molecular
periodicity that can be characterized by increased density, reduced
shrinkage, a measurable endothermic heat of melting, and discrete
x-ray scattering), if they do crystallize at all. Melt spinning of
polymers having a low propensity to crystallize (i.e., to form a
stable micromolecular crystalline structure) is quite difficult for
a number of reasons, including low melt strength, quench difficulty
and poor package formation. For example, various problems with melt
spinning of low melting (e.g., below about 160.degree. C.)
polyamides is described in U.S. Pat. No. 4,225,699, the entire
subject mater of which is incorporated herein by reference. The
most significant problem to overcome lies in the "sticking" of
filaments together and to the spin bobbin after being placed
thereon. In a typical melt spinning process, after spinning the
polymer into a multi-filament yarn, the yarn is quenched and then
wound onto a spin bobbin. Subsequently the yarn is removed form the
spin bobbin for further processing, such as drawing, annealing,
finishing, inserting, etc. If the yarn is not easily withdrawn from
the spin bobbin filament breakage occurs, resulting in a yarn that
cannot be processed into satisfactory products.
[0005] In order to reduce sticking of melt spun filaments composed
of low melting polymers, various processes and processing aids have
been developed. For example, U.S. Pat. No. 3,901,989, the entire
subject matter of which is incorporated herein by reference,
describes a process for melt spinning a bicomponent fiber using a
spin-draw technique that involves stretching or drawing of the
multi-filament yarn after spinning and quenching. However, such
spin-draw processes cannot be performed at high speed and are,
thus, not commercially viable for commercial-type applications.
[0006] Another process for alleviating the sticking phenomenon
relates to the quenching process. For example, improved cooling of
the fiber during the quench step by increasing the velocity of the
quench fluid is proposed in U.S. Pat. No. 5,411,693, the entire
subject matter of which is incorporated herein by reference.
However, the polymers utilized in this process melt at high
temperature ranges and have a high propensity to crystallize. This
process would not provide satisfactory results when spinning a low
temperature melting polymer that has a low propensity to
crystallize because such a filament's melt strength would be too
low.
[0007] The aforementioned U.S. Pat. No. 4,225,699 does describe
melt spinning of low melting polymers having a low propensity to
crystallize. However, the process recited therein is conducted at
low spinning speeds (i.e., 800 m/min.) and utilizes a spin draw
technique, thereby rendering the processing commercially
unacceptable for the reasons mentioned herein. Additionally, the
unwinding tension of the filaments from the spin bobbin is quite
high (i.e., above four grams) and is not suitable for existing
commercial yarn insertion processes due to the propensity for
breakage of the binder filaments.
[0008] There have been efforts to implement high speed melt
spinning of various polymers into fibers. For example, U.S. Pat.
No. 4,909,976, the entire subject matter of which is incorporated
herein by reference, describes a process for high speed melt
spinning of polyester using on-line zone cooling and heating.
However, polyester is a high melting temperature (i.e., above
250.degree. C.) polymer that exhibits a high propensity to
crystallize (i.e., to form stable micromolecular structures of
increased density) during the quenching process when spun at higher
speeds. In contrast, polymers possessing a low melting temperature
range with a low propensity to crystallize have not been melt spun
at high speeds due to a low expectation of success because the low
degree of stress induced crystallization expected from orienting
the amorphous polymer chains in the filaments emerging from the
quench zone. Such filaments typically must be further treated
(i.e., cooled, drawn, annealed, etc.) in order to reduce sticking
of the filaments placed on the spin bobbin, as mentioned in U.S.
Pat. No. 4,225,699.
[0009] Accordingly, there is a need for a commercially viable high
speed melt spinning process that produces acceptable non-sticking
filaments composed of polymers possessing a low melting temperature
range with a low propensity to crystallize.
SUMMARY OF THE INVENTION
[0010] The present invention relates to a method for high speed
melt spinning of a binder fiber by melting a polymer that exhibits
substantially no exothermic crystallization peak as measured by DSC
when it is cooled to solidification from a molten state according
to test A, spinning the polymer at a speed of greater than about
2000 meters per minute to form the binder fiber, and winding the
binder fiber onto a spin bobbin.
[0011] The present invention also is directed to a method for high
speed melt spinning of binder fiber bymelting a polymer having a
melting temperature range of greater than 0.degree. C. to
160.degree. C., spinning the polymer at a speed of greater than
about 2000 meters per minute to form the binder fiber and winding
the binder fiber onto a spin bobbin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 depicts a schematic of an embodiment of a process of
the present invention.
[0013] FIG. 2 is a graph representing melting characteristics of a
nylon 6/66/12 (Griltex.RTM. 1AGF) yarn sample as measured by a
differential scanning calorimeter (DSC).
[0014] FIG. 3 is a graph representing melting characteristics of a
nylon 6/69 yarn sample as measured by a DSC.
[0015] FIG. 4 is a graph representing melting characteristics of a
nylon 66 yarn sample as measured by a DSC.
[0016] FIG. 5 is a graph representing melting characteristics of a
functionalized polyethylene yarn (Herculon.RTM.) sample as measured
by a DSC.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0017] The carpets of the present invention may be made using,
instead of only conventional carpet fibers, a combination of fibers
comprising conventional carpet fiber and binder fiber. The term
"binder fiber", as used herein, refers to binder staple fiber or
binder monofilament or binder yarn, where the binder fiber may be
comprised exclusively of a binder material or a binder material
combined with a non-binder material. The term "binder material"
refers to a material that will melt or soften during heatsetting
and thereby mechanically and/or chemically bond conventional carpet
fibers together and the term "non-binder material" refers to a
material that will not melt or soften during heatsetting, such as
conventional carpet fiber. For example, the binder fiber may be in
the form of a yarn comprising binder fiber or conventional staple
fiber and binder fiber, or the binder fiber may comprise a
binder-non-binder material bicomponent fiber, such as a binder
material sheath over a non-binder material core, or a non-binder
material yarn coated with a binder material. The term "yarn" refers
to a staple fiber yarn (either a singles or a ply-twisted yarn) or
a bulked continuous filament (BCF) yarn (either singles or cabled
yarn). The present invention relates preferably to ply-twisted
yarns, comprising carpet yarn comprising a conventional staple
fiber yarn combined with binder fiber in the form of multifilament
yarn. The carpet made from these plied-yarn blends comprises a
primary backing and twisted evenly sheared, heatset pile yarn in
the form of individual lengths of plied yarn (tufts), each of which
projects upwardly from the backing and terminates as a cut end (cut
pile) or uncut end (loop).
[0018] Carpet fibers that may be utilized in making the fiber
blends of the present invention are typically crimped fibers having
deniers of at least 1 denier per filament (dpf) and a crimp
frequency of greater than 1 crimps-per-inch, and more preferably
between 5 and 16 crimps-per-inch. (The term "carpet fibers", as
used herein, refers to conventional carpet fibers (staple or
continuous filament) described in this paragraph and the term
"carpet yarn", as used herein, refers to yarns made from said
carpet fibers). Preferably, the carpet fibers have deniers of at
least 8, usually between 12 and 25, and a non-round cross-section
(e.g., trilobal cross-section). Preferred carpet fibers are
polyamides, particularly nylon 6 and nylon 66, polyesters,
particularly poly(ethylene terephthalate), olefins, particularly
polypropylene, acrylics, and combinations thereof. Other suitable
carpet fibers include other nylons and polyester fibers, such as
nylon 6/12 fibers or polybutylene terephthalate fibers. The carpet
fibers can also include additives such as light stabilizers, flame
retardants, dyes, pigments, optical brighteners, antistatic agents,
surfactants and soil release agents.
[0019] The binder material useful in making the carpet yarn of the
present invention typically has a melting range that falls between
60-190.degree. C., preferably of about 65-160.degree. C., more
preferably of about 70-140.degree. C., under ambient humidity
conditions (i.e., as described in Test A), where the melting range
is considered to be the endothermic portion of the DSC
(Differential Scanning Calorimeter) scan (scan rate of
approximately 20.degree. C./minute). Note: Endothermic transitions
for this class of low crystalline material will reflect polymeric
reorganizations, softening, and true melting, all here referred to
as comprising the melting range, and is demonstrated in the DSC by
deviation from the baseline. The binder material should also be
capable of wetting and spreading on the carpet fiber in order to
provide adequate adhesion during any subsequent dyeing steps and
final use. In the binder material, it may be advantageous to
utilize additives to reduce melt viscosity, enhance wetting
properties or modify melting temperature. In addition, special spin
finishes may be utilized which impart necessary antistatic and
lubricating properties to the binder material for efficient mill
processing. Preferably, the binder material is economic, compatible
with the conventional carpet fibers so as to enable it to adhere
thereto, and capable of being activated, i.e., melted or
sufficiently softened at the temperatures normally found in
conventional heatsetting apparatus such as a Superba.RTM. or
Suessen.RTM. heatsetting unit, available from American Superba,
Inc. and American Suessen Corp., respectively.
[0020] The binder material may be comprised of any polymer,
including any polymers having one or more components (i.e.,
copolymers, terpolymers, etc.), provided that they possess the
binder characteristics defined herein. The preferred binder
material is made from low cost components, such as nylon 6, nylon
66 and nylon 12. One example of such a binder material for
polyamide carpet fibers is a fiber melt spun from a copolyamide
comprised of nylon 6, nylon 66 and nylon 12 (referred to herein as
6/66/12, e.g., Griltex.RTM. 1AGF, available from EMS-Chemie, Inc.),
plus a chain terminator to control molecular weight. Another
example of a low cost binder material is the polyamide fiber spun
from copolymers of nylon 6 and nylon 69 or terpolymers of nylon 6,
nylon 66 and nylon 69. Of particular value is the 6/69 copolymer
comprised of about 25 to about 65 wt % nylon 6 (referred to herein
as 6/69). Copolymers in this composition range have a melting range
of greater than 0.degree. C. to less than about 150.degree. C. and
are readily melt spun. More preferred nylon 6/69 copolymers possess
melting ranges of greater than 0.degree. C. to less than about
130.degree. C. and are composed of about 35 to about 55 wt % nylon
6. Terpolymers generally give better adhesion, but are often more
difficult to melt spin. Examples of suitable 6/66/69 compositions
include 40/20/40 (wt %); 25/20/55 (wt %) and 40/10/50 (wt %),
available from Shakespeare Specialty Polymers. Other components or
precursors for making the copolyamide may be substituted for or
used in addition to any of the three components listed above, as
needed to achieve the desired binder fiber properties. Examples of
other suitable components include lactams, amino acids or salts of
diacids and diamines. Examples of diacids, which may be used along
with a diamine, such as hexamethylene diamine, are isophthalic
acid, undecanoic acid, docecanoic acid, azelaic acid and sebacic
acid. Examples of diamines, which may be used along with a diacid,
such as adipic acid are ethylene diamine, hexamethylene diamine and
nonamethylenediamine. The preferred components are those that are
readily available commercially and form linear copolyamides, which
may be melt spun on conventional spinning machines.
[0021] By selection of various component, their amounts, and
synthesis of the thermally activated, binder material, it is
possible to modify end-use properties of the finished carpet to
improve carpet aesthetics, particularly tuft (or loop) definition,
worn appearance retention, resilience, and fuzz/bearding. The
thermal shrinkage, tenacity, modulus, elongation to break, melt
viscosity, softening point, and melting point of the binder
material contribute to achieving ideal properties in the final
product. Moreover, various properties of the carpet fiber,
including denier-per-filament, cut length, fiber cross-section,
crimp type and frequency, surface finish, melt viscosity, and dye
affinity, among others, also affect the properties of the resulting
carpet.
[0022] In another embodiment, the binder fiber of the present
invention is constructed of a polymer that when melted exhibits
substantially no exothermic crystallization peak as measured by DSC
as it is cooled to solidification from a molten state. According to
the present invention, a method for conducting such a DSC test is
designated herein as Test A and is described as follows:
Test A
[0023] Test A is conducted as follows: The melting characterization
of binder fiber and carpet fiber samples (between 2 and 10 mgs)
after conditioning at 21 degrees Celsius and 61% relative humidity
for one day prior to testing are measured on a Perkin Elmer (PE)
Pyris 1 Differential Scanning Calorimeter (DSC) equipped with a
sub-ambient cooling unit and continuously purged with nitrogen gas.
Fiber samples of 2 to 4 mm length are prepared using a cutting
board and razor blade, then encased in a DSC pan using the PE pan
crimper and vented with five punched holes. To assess melting
behavior and propensity to recrystallize, each sample is held at
-50 degrees C. for 5 minutes heated at 20 degrees C. per minute to
200 degrees C., held there for 5 minutes, then cooled to -50
degrees C. at 20 degrees C. per minute where again it is held for 5
minutes before reheating to 200 degrees C. at 20 degrees C. per
minute.
[0024] As shown in FIG. 2, the Griltex.RTM. 1AGF exhibits major
endothermic peaks at about 70 degrees C. and between about 108 and
122 degrees C.; no exothermic recrystallization peaks are evident
on cooling; and no endothermic melting peaks above 100 degrees C.
are evident on reheating.
[0025] FIG. 2 is a graph representing melting/cooling/remelting
characteristics of a nylon 6/66/12 (Griltex.RTM. 1AGF) yarn sample
as measured by DSC using Test A. As is readily apparent from the
graph, the polymer exhibits substantially no exothermic
crystallization peak when it is cooled to solidification from the
molten state. "Substantially" no exothermic crystallization peak
means that the peak area of the exothermic peak is less than 10
percent of the area of the endothermic reorganization/melting peaks
obtained for the initial melting by drawing a baseline from 20 to
160 degrees C. and measuring the endothermic areas above said
baseline.
[0026] FIG. 3 is a graph representing melting characteristics of a
nylon 6/69 yarn sample as measured by DSC using Test A. As is
readily apparent from the graph, the polymer exhibits substantially
no exothermic crystallization peak when it is cooled to
solidification from the molten state. As used herein, "melting
characteristics" represent the melting, cooling and remelting of
yarn samples in accordance with the method described in Test A.
[0027] In contrast, FIGS. 4 and 5 represent melting characteristics
of polymer yarn samples that demonstrate substantial exothermic
crystallization peaks when cooled to solidification from molten
states.
[0028] In accordance with the present invention, it has been
discovered that binder fiber made from polymers that exhibit no
exothermic crystallization peaks when cooled to solidification from
a molten state using Test A provide improved results in various
textile applications. Inserting binder fibers made from each of the
polymers documented in Table I (at the 2 percent level into a nylon
66 staple yarn) improved carpet wear (AR), and carpet tuft
endpoint. The N6/N66/N12 and N6/N69 (Examples I and IV) binder
fibers in particular, showed significantly better results for
carpet wear (AR) and carpet endpoint. Both lacked evidence of
recrystallization on cooling from the melt via Test A.
[0029] Moreover, under the present invention it has been further
discovered that such polymers may be unexpectedly melt-spun into
fibers using high speeds (e.g., above about 2000 mpm). Low speed
spinning attempts failed to produce acceptable packages (bobbins)
of continuous filament yarn that were made from melt-spun fibers
from polymers characterized by low-melting temperature. The fibers
stuck to one another and couldn't be unwound at the speeds
encountered during further processing. While this problem could be
solved by introducing further processing steps (heating and/or
drawing), it was unexpectedly found that spinning these polymers at
speeds above 2000 mpm increased the spin-line stress on the
filaments enough to make the resultant spun packages usable.
Evidently, the resultant changes in fiber morphology--increased
molecular orientation and the beginnings of
crystallization--limited the fiber's stickiness. It is not obvious
that this degree of molecular change (evidenced by a reluctance to
recrystallize on cooling from the melt) would reduce the degree of
stickiness. One of ordinary skill in the art would have expected
this low degree of crystallization to not impact the degree of
stickiness, as opposed to other more readily crystallizable
polymers such as the nylon 6/66 copolymer or the functionalized
polyethylenes. As is readily apparent from Table II, spinning
speeds of the low crystalline polymers of the present invention of
greater than about 2000 mpm clearly provide fibers that possess an
unexpected degree of reduced stickiness. Preferably, the polymers
may be melt-spun into fibers at speeds above about 2500 mpm, more
preferably above about 3000 mpm, and most preferably above about
3500 mpm.
[0030] The conventional carpet manufacturing process for staple
carpet fiber takes randomly oriented carpet fibers and subjects
them to a series of carding and pinning operations to blend and
orient the individual carpet fibers in a common direction. The
final drafting stage, spinning, imparts twist to form a continuous,
singles yarn comprised of many short fibers twisted together;
commonly 40-150 fibers would be found in any cross-section. In the
present invention, binder fiber may be blended as staple fiber with
the conventional carpet staple fibers in the early stages of
carding or inserted as a continuous binder fiber yarn after the
final drafting into the spun singles package.
[0031] Two or more conventional carpet singles yarns may then be
twisted together using a variety of plytwisting processes: e.g.,
ring twisting, 2-for-1 twisting, or open-ended twisting. The
present invention relates preferably to inserting the binder fiber
as a yarn prior to plytwisting. This may be accomplished employing
a variety of different techniques, and the binder fiber is
preferably positioned between at least two singles yarns. The
binder fiber may be inserted during a doubling process, also
referred to as a parallel winding, whereby the binder fiber is
joined with two other singles yarns and subsequently wound onto a
package that is 2-for-1 twisted. Another method is to join the
binder fiber with a singles yarn and wind onto a package via a
Murata.RTM. (available from Murata Machinery, LTD),
Schlafhorst.RTM. (available from W. Schlafhorst and Co.) or other
auto winder device. The binder fiber/singles package is then placed
into a 2-for-1 twister along with a second singles package
containing no binder fiber. Still another process involves
inserting the binder fiber directly into a ring twister from a
creel containing two singles yarns and a binder fiber bobbin. A
technique also exists which allows for direct insertion of the
binder fiber into the Murata.RTM., Schlafhorst.RTM. or other auto
winder device such that the package formed is available for 2-for-1
twisting with a second package containing no binder fiber insert.
Then the yarn is processed through a conventional heatsetting unit
such as a Superba.RTM. or Suessen.RTM. to set the imparted twist
and in the present invention to melt or soften the binder fiber.
Typically, Superba.RTM. heatsetting subjects the nylon 66 yarn to
temperatures of 132-138.degree. C. in a pressurized steam
environment and Suessen.RTM. heatsetting subjects the nylon 66 yarn
to temperatures of 195-200.degree. C. in a superheated steam
environment. The heatset yarns may then be tufted into carpet and
dyed conventionally to produce cut-pile saxony, cut-pile textured,
loop, and combination loop and cut-pile carpets.
[0032] FIG. 1 represents an embodiment of a process according to
the present invention. In one embodiment, Griltex.RTM. 1AGF, a
commercially available nylon 6/66/12 ( Griltex.RTM. 1AGF) copolymer
resin from EMS-Chemie (North America) Inc., a 0.32 percent moisture
level, and a 1.56 relative viscosity (measured in sulfuric acid
according to ASTM D4066) is spun at a melt temperature of 160
degrees C. Spinneret 22 contains round capillaries having lengths
of 0.015" (0.38 mm) and diameters of 0.020" (0.51 mm). Quench zone
24 is 35 inches in height, and is supplied with 20 degree C. quench
air having an average horizontal velocity of 1 foot (30.5 cm) per
second. Filaments 26 are converged into yarn 28 approximately 36
inches (91.4 cm) below the spinneret. A conventional, low friction
spin finish is applied to yarn 28 by finish roll 32. Yarn 28 next
passes in partial wraps about godets 34 and 36, the speed of which
are 4450 meters per minute and 4500 meters per minute,
respectively, to prevent the yarn from wrapping on godet 36. The
polymer metering rate is selected such that the yarn is wound onto
a bobbin 38 at a denier of 70. The winder used is the Toray 601,
and the winder speed (about 4435 meters per minute) is adjusted to
provide a winding tension of 0.1 grams per denier.
[0033] The following examples are included to demonstrate preferred
embodiments of the invention. It should be appreciated by those of
skill in the art that the techniques disclosed in the examples
which follow represent techniques discovered by the inventors to
function well in the practice of the invention, and thus can be
considered to constitute preferred modes for its practice. However,
those of skill in the art should, in light of the present
disclosure, appreciate that many changes can be made in the
specific embodiments which are disclosed and still obtain a like or
similar result without departing from the spirit and scope of the
invention.
EXAMPLES I-IV
[0034] These examples illustrate the preparation of carpet
fiber/binder fiber blends of the invention and the improved worn
surface appearance and initial carpet aesthetics characteristics
(e.g., tuft endpoint) of cut-pile carpet made therefrom. Test
carpets are made using conventionally crimped nylon 66 carpet
staple fibers which are uniform in appearance and have a length of
71/2 inches, a denier of 15, and an average of 10.5 crimps per
inch. These fibers are carded and spun into singles yarn; the
singles yarn inserted with a 70 denier/10 filament binder fiber
(Example I: N6/N66/N12 binder fiber; Example II: N6/N66 binder
fiber; Example III: functionalized PE binder fiber; Example IV:
N6/N69 binder fiber) at parallel winding through the Maratag (at
speeds of 1200 mpm); then a singles without the binder fiber and a
singles with the binder fiber are plied together in a 2-for-1
twisting operation. Though multiple comparisons were made
contrasting carpets made from yarns inserted with the binder fiber
against carpets not inserted with the binder fiber--both made under
the same yarn and carpet constructions--(73 for Example 1, 7 for
Example 2, 6 for Example III, and 2 for Example IV) under a variety
of yarn and carpet construction parameters, a typical plied yarn is
made at a 3.5/2 cotton count (cc) and twisted at 5.25Z
(singles).times.5.25S (ply). Test yarns, including those with
binder fiber, are textured and heatset (stuffer box and Suessen at
200.degree. C.), tufted into a textured cut-pile carpet
construction (45 oz face weight, 18/32" pile height, 5/32 gauge is
typical), and then continuous fluid dyed to a variety of
shades.
[0035] Appearance loss between each of the untrafficked and
trafficked (20,000 steps) carpets is determined by evaluating the
appearance retention (AR) of the walked carpet using a single
grader knowledgeable in the area of carpet testing and reference
photographs in the manner described in ASTM D2402. The grader
determines an ASTM grade for two, replicate carpets of each
trafficked, Test carpet and averages the grade: the lower the
average grade, the lower the perceived change in the test carpet's
appearance after trafficking. The AR contrast is the AR grade of
the Test carpet blended with the binder fiber minus the AR grade of
the Test carpet excluding the binder fiber. Except for the binder
fiber, both Test yarns and carpets are constructed identically.
[0036] Untrafficked carpet aesthetics, here tuft endpoint
definition, is determined by contrasting the relative endpoint
definition--the tighter, better defined the tuft endpoint, the
better--of an untrafficked Test carpet inserted with the binder
fiber against a Test carpet made without the binder fiber but
otherwise constructed identically. Nine degrees of contrast [from
much worse (-2) to much better (+2) in half grade increments] are
assigned by a single grader knowledgeable in the area of carpet
testing.
[0037] The results, as set forth in Table I, clearly indicate that
the carpets of Examples I and IV, prepared from polymers of the
present invention, produce carpets superior in appearance retention
(-1.13 and -1.50 AR) and untrafficked carpet tuft endpoint (+1.02
and +1.00 endpoint) to identically constructed carpets lacking the
binder fiber. Carpets of Examples II and III, prepared from
polymers outside the present invention, exhibited significantly
less improvement in AR (-0.49 and -0.17) and endpoint (+0.64 and
+0.10) between carpets made with the binder fiber insert and
carpets made without a binder fiber insert.
EXAMPLES IV-XIII
[0038] Binder yarns are fabricated according to the process
referred to in FIG. 1, but at different spinning speeds, as
indicated in TABLE II. All yarn packages to be tested are
conditioned at 21 degrees C. and 65% relative humidity for one day
prior to testing.
[0039] Test B is conducted at follows: The binder yarn's unwinding
characteristics are measured one week after spinning. Each bobbin
of binder yarn is subjected to the following characterization.
Fifty yards of binder yarn are stripped from the bobbin and
discarded. The binder yarn is then unwound at a 100 mpm speed and
the tension (gms) measured every one-half second for a 12 minute
period (1200 meters of yarn tested, 1440 measurements taken) using
a tensometer available from Tension Measurement, Inc. The
percentage of data involved in a stick point (Stick (%)) (defined
as greater than 4 grams force measured), the average tension (Avg
(gms)) and standard deviation of tension (St Dev (gm)) of data
excluding those data involved in stick points, and the percentage
of data measuring less than 0.5 gms force, 0.5-to-1.5 gms force,
2.5-to-3.5 gms force, and greater than 3.5 gms force are recorded
in TABLE II. These results clearly demonstrate the unexpected
reduction in stickiness of the fiber: Example V could not be pulled
from the bobbin, Examples VI, VII, VIII, and IX show much higher
percentages of the data are involved in stick points and those data
not involved in stick points exhibiting higher average tensions and
greater percentages of the data at higher tension levels than
Examples X, XI, XII, and XIII.
1TABLE I Carpet Property Contrast Between Inserted and Uninserted
Carpets Insert Yarn Types Example II Example III Example IV Example
I (N6/N66) (Func PE) (N6/N69) (N6/N66/N12) (MP: 170- (MP: 120- (MP:
130- (MP to 110 C) 180 C) 135 C) 135 C) Compari- 73 7 6 2 sons:
(Average) -1.13 -0.49 -0.17 -1.50 AR Contrast (+/-0.13)* Endpoint
+1.02 +0.64 +0.10 +1.00 Contrast (+/-0.12) *95% Confidence Interval
(72 degrees of freedom)
[0040]
2TABLE II Binder Yarn Bobbin Unwinding Properties according to Test
B Spinning Speed Stick Avg St Dev <0.5 gm 0.5-1.5 gm 1.5-2.5 gm
2.5-3.5 gm >3.5 gm Examples (mpm) (%) (gm) (gm) (%) (%) (%) (%)
(%) V 500 * * * * * * * * VI 1000 8.30 2.54 0.78 1.2 6.9 10.2 14.9
64.7 VII 1500 4.20 1.57 0.74 0.0 51.4 26.9 10.8 11.0 VIII 2000 6.35
1.47 0.63 29.9 23.2 16.6 11.2 19.1 IX 2500 1.36 1.04 0.88 42.3 26.6
21.6 6.7 2.8 X 3000 0.08 0.49 0.38 66.6 31.0 2.3 0.0 0.1 XI 3500
0.00 0.22 0.08 99.3 0.7 0.0 0.0 0.0 XII 4000 0.00 0.36 0.17 86.2
13.7 0.1 0.0 0.0 XIII 4435 0.60 0.34 0.31 85.9 11.0 0.7 0.5 2.0
*The yarn could not be removed from the bobbin due to extreme
adhesion.
* * * * *