Note: Descriptions are shown in the official language in which they were submitted.
27996
_LYO~EFIN PROD~CTS AND METXODS OF MAKING
Background of the Invention
The present invention relates to a process for making fibrous
polyolefin products by melt spinning and products thereof.
While fibrous polyolefins, particularly polypropylene, have
been found to possess certain characteristics superior to other
synthetic fibrous materials, it is generally recognized that fibrous
polyolefins have peculiarities not possessed by other synthetic fibers,
; which of-ten limit the processability of such materials and limit the end
uses to whlch the products can be applied. For example, the
processability limitations result in relatively low extrusion, spinning
and wind-up speeds. Often high breakout rates are experienced and
further processing of the spun fibers is limited, to the extent that
inconsistent texture, broken filaments, lack of color control and
difficulty in knitting and weaving are often encountered~ The products
produced by melt spinning polyolefins also have relatively high spun
denier, low tenacity, low birefringence, high elongation, high boiling
water shrinkage, low modulus of elasticity, as well as other limitations
which limit the uses to which the fibrous materials can be applied. It
is also recognized that polyolefin fibers cannot generally be utilized in
their as-spun state, i.e., with little or no further processing.
It is therefore an object of the present invention to provide
an improved process for producing fibrous polyolefin products which
overcomes the above-mentioned and other disadvantages of prior art
~; processes and improved fibrous polyolefin products which overcome the
above-mentioned and other disadvantages of prior art products. Another
object of the presen-t invention is to provide a process for producing
melt spun, fibrous polyolefin products and fibrous polyolefin products
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which can be utilized with little or no additional processing. Another object
of the present invention is to provide an improved process for producing
fibrous polyolefin products which can be carried out at relatively high
speeds, par-ticularly higher speeds oE ex-trusion, spinning and wind-up.
Another and further object of the present invention is to provide an improved
process for producing fibrous polyolefin products which result in products of
a low spun denier with consequent lower draw ratios and improved products
thereof. Yet another object of the present invention is to provide an
improved process for producing fibrous polyolefin products of improved
processability, particularly reduced breakout, higher draw ratios, higher and
more constant twist levels during false twist texturing, better ease of
handling in knitting, weaving, etc., improved color control and improved
products thereof. A still further object of the present invention is to
provide fibrous polyolefin products of improved coherency and/or bulkiness.
These and other objects of the present invention will be apparent from the
following description.
Summary of the Invention
In accordance with the present inven-tion, novel polyolefin filament
products are produced by melt spinning a polyolefin having a molecular weight
dis-tribution of less than about 7 (a MW/MN ratio determined by gel permeation
chromatography) and a melt flow of between about 20 and about 60 which are
- useful in -their as-spun condition without further processing and have high
.~ tenacity, high birefringence and low elongation. In other aspects, the novel
` products can be converted to other useful products by one or more additional
processing steps, including improving the coherency and/or bulkiness by heat
setting, texturing, jet texturing such as using a Taslan jet, (a Trademark of
E. I. duPont deNemours and Co.), plying, entangling, and cutting into staple.
Still another aspect of the process includes drawing the melt spun fibers,
twist-drawing, draw-texturing, draw-twisting, draw-winding, and/or
draw-entangling.
Detailed Description
The process of the present invention comprises producing
polyolefin, particularly polypropylene filament products by melt
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spinning a polypropylene having a molecular weight distribution of less
than about 7 and a melt flow between about 20 and about 60.
The term "molecular weight distribution", as utilized herein,
refers to the ra-tio of the weight average molecular weight to the number
average molecular weight. The term "melt flow", as utilized herein,
refers -to the weight in grams of the polymer which can be extruded within
a particular time under a constant dead weight load at a given
temperature as determined by ASTM-D~1238, Condition "L". The term "as-
spun" as used herein, refers to the filament products of the invention in
their condition when taken up on the first wind up package after having
been melt spun. Various terms have been used in the art -to designate
treatments of a plurality of collected filaments or a yarn and a
plurality of yarns to improve the coherency of the filaments and/or
improve the bulk of the yarn. A process in which the yarn or yarns are
heated, twisted, cooled and then untwisted is generally referred to as
"false-twist texturing" or simply "texturing". This terminology is
almost universally accepted and will be utilized as above defined in the
present appl:ication. By contrast, where a yarn or yarns is -twisted but
not subsequently untwisted, the universally accepted terms which will be
used herein are "true twist" or simply "twis-t". Some confusion exists
however in the terms used to describe other such treatments, particularly
where the yarn or yarns are subjected to a jet or jets of air under
pressure. In the latter instance, the results produced and the
terminology applied depends upon the condition of treatment, such as air
pressure, the direction of the air jet relative to the path of yarn
travel and the relative tension being applied to the yarn during
treatment. The term "Taslan texturing" (Taslan is a trademark of
E.I.duPont de Nemours and Company) as used herein is meant to refer to a
process and product in which a jet or jets of air are directed against
the yarn, usually in the direction of travel of the yarn, forming a
turbulent region, the speed or tension on the yarn is greater at the
entrance to the jet than at the exit (net overfeed) and the filaments of
the resultant product have a multitude of ring-like loops, coils and
whorls at random intervals along their lengths. The term "entangling" or
"intermingling", sometimes called "interlacing" as used herein, refers
to a process and product in which a jet or jets of air are directed
;; against the yarn or yarns, usually at a 90 angle to the yarn path, the
speed or tension on the yarn is substantially the same at the entrance
271~
and exit of the intermingler and the resultan~ product has a high degree
of intermingling or entangling of the filaments but is substantially free
of loops, coils and whorls. Finally, "plying" is used -to refer to a
process and products in which two or more yarns are formed into a single
yarn by twisting or intermingling in a jet. The terms "cold draw" or
simply "draw" refers to a process in which filaments or yarns are drawn
or stretched (with or without heat and during or after windup) after the
spun filaments have solidified as opposed to drawing which occurs during
the spinning of the filaments and before the solidification thereof.
Stretching which occurs while spinning and before the filaments have
solidified will be referred to as "melt drawing" and the products thereof
as "partially oriented" products. The term "finish" indicates a liquid
composition applied to the yarn during melt spinning that acts as a
lubricant and imparts desirable characteristics-to the yarn.
In a preferred embodiment, melt spinning is carried out at a
take-up speed within the range of about 1200 to 5000 meters per minute
and still more preferably between about 1500 and 4000 meters per minute.
In another embodiment unique products are obtained by melt
spinning, carried out at take-up speeds in the range of 800-1200 meters
per minute, draw-texturing at least three of the yarns as spun with the
direction of twist for two yarns being different from the third, then
. plying the yarns in an interlacing jet. The product of this embodiment
is simul-taneously draw-textured at a draw ratio of 4.0 to 1 to 2.0 to 1.
The products produced in accordance with the present invention
have a number of advantageous characteristics not heretofore present in
melt spun polyolefins. Specifically, the polyolefin filaments have a
spun denier below about 25 per filament. In the as-spun condition, the
products have a high birefringence, usually in excess of about 0.015.
The products also have low elongations between about 100 and 350 percent
30 as measured by ASTM Method 2256 and preferably in the range of about 100
to 250 percent. In the alternative, drawn filament materials can be
produced having conventional spun deniers but which are drawn at lower
draw ratios. The as-spun products also have a high tenacity above about
2.4 grams/denier and, to the extent that the filament ma-terials are
further processed by drawing or twisting, higher cold draw ratios may be
utilized. For example, draw ratios within the range of 2.0/1 to 4.0/1
can be utilized.
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While the polyolefin filament products of the present
invention are useful in their as-spun condition, these products can be
fur-ther processed by a wide variety of treatments -to form the same into
yarns of desired characteristics for use in a variety of textile
products, such as woven or nonwoven material, tufted products and the
like. For example, the products may be heat set and entangled. Such
processes to improve the coherency may be performed during the spinning
operation (prior to winding up) or after collecting the fibers and
winding the same. ~xcellent products can also be produced by crimping,
such as stealn crimping, or stuffer box crimping and cutting the crimped
ma-terials into staple. The as-spun products of the present invention can
also be further improved by subjecting the same to further processing
which includes cold drawing. Such processing can involve spin-drawing,
twist-drawing, false-twist texturing, draw-texturing, draw-twisting, and
draw-Taslan texturing.
The preferred polyolefin, fiber-forming materials for use in
accordance with -the present invention are homopolymers of polypropylene.
However, a fiber-forming resin comprising a copolymer of propylene
wi-th a small amount (less than 15%) of an olefinic monomer, such as
e-thylene, butene or a diene monomer, such as butadiene, isoprene, etc,
may be employed. If desired, a fiber-forming resin blend composed of a
predominant amount of a propylene polymer and a small amount (less than
15%) of at leas-t one polymer of the above mentioned olefinic or diene
compound may be used. Therefore the term "polypropylene" as used herein
is intended to include the propylene homopolymers, polymer blends and
copolymers mentioned above. As for the fiber forming resin, it is
preferable -to employ a crystalline polypropylene homopolymer having a
molecular weight distribution of less than about 7 and a melt flow of
between about 20 and about 60.
The present invention will be more readily understood by
reference to the drawings.
Brief Description of the Drawings
FIGURE 1 schematically illustrates a melt-spinning process for
producing an as-spun product;
FIGURE 2 schematically illustrates an embodiment in which a
yarn is twist-drawn;
FIGURE 3 schematically illustrates several techniques for
improving the coherency and/or bulking a yarn;
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FIGURE ~ schematically illustrates an embodiment in which a
yarn is sequentially draw-textured;
FIGURE 5 schematically illustrates an embodiment in which a
yarn is simultaneously draw-textured;
FIGURE 6 schematically illustrates in slightly greater
detail a false-twist texturing operation;
FIGURE 7 schematically illustrates a spin-draw embodiment;
FIGURE 8 schematically illustrates an embodiment in which a
yarn is draw-twisted;
FIGURE 9 schematically illustrates an embodiment in which two
yarns are draw-Taslan-textured;
FIGURE lO schematically illustrates an embodiment including
crimping and cutting into staple; and
FIGURE ll schematically illustrates an embodiment in which a
plurality of yarns are draw-textured and interlaced.
In referring to the drawings it should be recognized that the
spatial relationships of -the elements are not necessarily those which
would be u-tilized in a commercial operation and that certain elements and
items oE equipment have been enlarged with respect to other elements or
items of equipment so that the character thereof can be illustrated in
somewhat greater detail.
In accordance with FIGURE l, which illustrates one embodiment
` of the present invention, a plurality of filaments are melt spun from
spinneret 10. The filaments 12 then pass through a quench zone 14 where
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they are cooled by blowing air therethrough. Applicator 56 applies a
finish to the yarn. The filaments 12 then pass through converging
guide 16 where they are collected to form a yarn 18. Converging guide
16, as will appear hereinafter, may be a pigtail type eyelet, a slo~ted
roller, or any conventional converging or collecting means. The yarn 18
then passes to a conventional winder wherein traversing guide 20 moves
~ laterally to wind the yarn and form a package 22. The drawing that
;~ occurs between the spinneret lO and the take-up package 22 provides
partial orientation of the yarn. As has been pointed out previously,
filaments and yarn made in accordance with the present invention are
useful for various purposes in their as-spun condition with no subsequent
processing or treatment other-than that shown in FIGURE 1.
FIGURE 2 of the drawings shows another embodiment of the
present invention wherein yarn, produced in accordance with FIGURE 1, is
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fur-ther processed by twist-drawing. In accordance with FIG. 2, a yarn
package 22, such as that produced in FIG. 1 is mounted on twister 24.
The yarn is drawn off package 22 and passes through pretension gate 26,
thence through the core of package 22 and through rotatable spindle 28.
Twister 24 is referred to as a "two-for-one twister" in that it inserts
two turns of -true twist for each rotation of spindle 28. The twisted
yarn then passes through guide elements 34 and 36. The yarn is wrapped
several times about feed rolls 42 and several times about draw rolls 46
which operate at speed greater than rolls 42 and thus draw or stretch
the yarn in the zone between the rolls. Optionally, the drawn yarn can
pass over heater 44 to rolls 46 to heat the yarn during drawing, or the
rolls 42 and 46 can be heated, eliminating the need for hot plate heater
44. From draw rolls 46 the yarn passes over stationary guide 48 and
thence through traverse guide 50 of a winder, which ultimately forms
package 52. A more detailed description of the operation shown in FIG.
2 can be found in U.S. Patent 3,775,961.
FIG. 3 illustrates a modification of the present invention in
which one or more treatments are given to the as-spun yarn 18 to improve
the coherency and/or bulkiness of the filaments of the yarn. These
treatments include entangling the yarn and/or heat setting the yarn.
Specifically, the plurality of filaments 12 pass over ceramic guide 54
where they are collected or converged in the same manner as in
; eyelet-type converging guide 16 of FI&. 1, tO form the yarn 18. The
yarn 18 may then be passed over applicator 56 which applies a finish to
the yarn and thereby improves the coherency of the filaments of the
yarn and acts as a lubricant during processing. Finish applicator 56,
as shown in the drawing, is what is known as a "kiss roll". The
yarn 18 then passes over ceramic guide 58 and thence -to godet
rolls 60. From godet rolls 60 the yarn passes through a jet type
entangler 62. Entangler 62 may be of the type shown and described
in U.S. Patent 2,783,609. In this type of entangler the filaments
of the yarn are intermingled, but have no significant coils, loops
or whorls, by a high velocity air jet. This treatment improves the
coherency oE the filaments of the yarn for windup. The entangled yarn
then passes to winder 64 where it is wound on package 66. It should
be recognized at this point that the finish applicator 56 and
entangler 62 may be used alone or in combination and that either or
both may be placed in any oE a number of differen-t positions between
converging guide 54 and winder 64. In an alternative form of improving
the coherency oE the filaments of the yarn, the yarn package 66 may be
placed in an autoclave 68 where the yarn is heat set at about 120C. The
heat-set yarn also has improved coherency of the filaments when used
alone or it may be used in combination with the application of a finish
and/or entangling.
FIGURE 4 of the drawings illustrates yet another embodiment of
the pxesent invention wherein the yarn 18, as produced in FIGURE 1, is
subjected to a subsequent treatment involving draw-texturing. In
accordance with -the embodiment of FIGURE 4, the yarn 18 passes around
input rolls 70 thence about hot pin 72 or across an appropriate hot plate
and finally around draw rolls 74 which are rotated at a speed greater
than input rolls 70 to thereby stretch or draw the yarn. The drawn yarn
then passes over a plate-type first stage heater 76. From heater 76 the
yarn passes through a disc-type, false--twist spindle 78. From disc-type
false-twist spindle 78 the yarn passes between intermediate rolls 80 and
thence to second stage heater 82. From second stage heater 82 the yarn
passes through output rolls 84 and thence to takeup package 86 which is
. driven by package drive roll 88. It should be noted that a conventional
false twist spindle could be substituted for the disc type illustrated
here and in the other embodiments.
FIGURE 5 of the drawings illustrates an alternative form of the
method of FIGURE 4 which is referred to in the art as simultaneous draw-
texturing. It is to be observed that the process of FIGURE 5 differs
25 from that of FIGURE 4 only to the extent that hot pin 72 and rolls 80 are
- eliminated and the yarn is heated and drawn simultaneously with the
inser-tion of false twist to the yarn by positioning draw rolls 74
downstream of disc-type false-twist spindle 78.
FIGURE 6 oE the drawings, although schematic in nature, shows
in somewhat greater detail the false twist tex-turing operation and
graphically illustrates why it is referred to as "friction" false
twisting. Specifically, the yarn 18 passes over first stage heater 76
and thence to disc-type false-twist spindle 78, illustrated as an array
of rotating friction discs that impart false twist to the yarn. In the
zone containing first stage heater 76 to disc-type false-twist
spindle 78, twist is inserted and heat set in the yarn. From t~e lower
end of heater 76 to disc-type false twist spindle 78 a cooling zone makes
up the lower or downstream portion of the twist-heat-set zone. After
passing through disc-type falso twist spindle 78 and -thence to inter-
mediate feed rolls 89, so the yarn is untwisted. Since the previous
treatment twisted the yarn and heat set this twist the untwis-ting will
not straighten the elemen-ts or filaments but instead results in a yarn
whose coherency and bulkiness are improved by the false twisting.
EIGURE 7 of the drawings illustrates yet another embodiment of
the present invention wherein a yarn is formed by a simple spin-draw
operation. In accordance with FIGURE 7 the yarn 18, formed by passage
10 over converging guide 54, passes over feed rolls 90, thence to heater 92
and draw rolls 94, operating at a higher speed than rolls 90.
- EIGURE 8 of the drawings shows yet another after-treatment to
which the as-spun yarn of FIGURE 1 can be subjected. Specifically, the
operation of FIGURE 8 is what is generally referred to as draw-twist. In
15 accordance with FIGURE 8 the yarn 18 from package 22 passes over feed
rolls 96, over heater 98 and thence over draw rolls 100. The latter, of
course, are operated at a speed higher than the speed of feed rolls 96 to
thereby stretch Gr draw the yarn. The drawn yarn then passes through
- ~ guide 102 and thence to rotatable flyer 104 which winds the yarn up on
20 pirn 106. As flyer 104 rotates, it inserts true twist in the yarn. It
~ should be recognized at this point that a spin-drawn yarn, prepared in
- accordance with FIGURE 7, or a draw-twisted yarn prepared in accordance
with FIGURE 8 may thereafter be subjected to a false twist-texturing
operation, as performed in the double heater, false-twist texturing
machines illustrated in FIGURES 5 and 6 of the drawlngs.
FIGURE 9 illustrates an after treatment of the as-spun yarn
produced in FIGURE 1 wherein the yarn 18 is draw-Taslan textured (a
Trademark of E. I. du Pont de Nemours and Co.) as an effect yarn and
combined with a core yarn 19. In accordance with FIGURE 9 the yarn 18
30 from package 22 is passed through a draw zone comprising feed rolls 108,
heater 110 and draw rolls 112 and feed rolls 113. From the draw zone
the yarn 18 is passed to a Taslan jet (a Trademark of E. I. du Pont
de Nemours and Co.) 114. Core yarn 19 from package 23 is passed by
feed rolls 115 operating a~ a slower speed than rolls 113 to a Taslan
jet (a Trademark of E. I. du Pont de Nemours and Co.) 114. As
previously indicated, the yarns in passing through Taslan jet 114
are subjected to turbulence in a high velocity air stream and
separated from the air stream by being jetted agains-t baffle 116 and
then -~urned in a generally perpendicular path. Due to the overfeed
of yarn 18, it becomes the effect yarn. Passage through the
jet 114 results in the filaments of the yarn forming loops,
rings and whorls therein and effecting some intermingling of the
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filaments. Generally, the yarns are under tension as they enter Taslan
jet 114 and as the core and effect yarn 1]9 exits Taslan jet 114 it is
-traveling at a reduced speed and this reduction in tension during the
turbulence contributes to the formation of the loops, etc. The yarn 119
then passes -through guide 118 to takeup rolls 120, thence through
traverse guide 122 of a winder and onto a package 124. Taslan je-t 114 is
of the type well known in the art and will not be further described
herein.
The embodiment of the presen-t invention shown in FIGURE 10
subjects the yarn 18, produced in accordance with FIGURE 1, to a
subsequent treatment involving crimping of the yarn and, optionally,
cutting the crimped yarn into staple. Specifically, the yarn 18 is fed
to crimper 126 which comprises feed rolls 128 and stuffer box 130. The
specific crimper shown is a steam crimper and a preferred steam crimper
15 is shown and described in U.S. Patent 3,911,539. From the stuffer box
130 the crimped yarn passes to J~box 132, over tensioning rolls 134 and
thence to staple cutter 136. Staple cutter 136 cuts the crimped yarn
~- in-to short fibers or staple which are then passed to bailer 138. At this
point it should be recognized that additional finish may be applied to
the yarn prior to passage -through crimper 126 and the yarn may be cold
drawn prior to the crimping operation.
FIGURE 11 of the drawings illustrates a novel technique for
forming a plied and interlaced yarn from a plurality of draw-textured
yarns produced in accordance with the draw-texturing operations
illustrated in FIGURES 4, 5, and 6. Preferably, a plurality of yarns are
simultaneously draw-textured as illustrated in FIGURE 5. Specifically,
three separate yarns 18A, 18B and 18C, respectively, are simultaneously
draw-textured by passing the same through disc-type false-twist spindles
78A, 78B and 78C, draw rolls 74A, 74B and 74C, second stage heaters 82A,
. 30 82B and 82C and outpu-t rolls 84A, 84B and 84C. While the draw-texturing
devices are shown as offset in FIGURE 11, for clarity of illus-tration
only, it is to be understood that units A, B and C would be in side-by-
side rela-tionship in actual operation. The draw-textured yarns 18A, 18B
and 18C are thereafter passed through an entangling or in-terlacing device
35 140 which plies the yarns together. The interlacer 140 is the same type
entangler or interlacer as 62, referred to in the description of FIGURE 3
for a single yarn. Interlacer 140 generally comprises a tube through
which a plurality of yarns are fed. The tube through which the yarns
ll
pass is provided with air from an annular plenum zone supplied with air
by means of air supply 142. To aid in stringup of the yarns in
interlacer 140, the interlacer is provided with a slot 144, which is
preferably at an angle so as to aid in retention of the yarns in the yarn
tube. The interlaced yarn then is wound up on takeup package 146 driven
by package drive roll 148. It has been found in accordance with the
present invention that -the system of FIGURE 11 is particularly useful in
the produc-tion of a heather-type yarn, in which three different colors of
yarn are plied by interlacing. Specifically, it has been found, in
accordance with the present invention, that, in a system such as that of
FIGURE 11, if a plurality of yarns to be interlaced are all twisted in
the same direction this results in a high torque being applied to the
yarns. ~lowever, it was discovered -that if alternate ones of the
plurality of yarns were false twisted in the opposite direction, this
undue torque was essentially eliminated and a heather-type yarn of
. substantially improved characteristics was produced. This is
- illustrated in FIGURE 11 by the rotational direction arrows applied -to
false-twist spindles 78A, 78B and 78C. In this particular illustration,
where three yarns are interlaced, the middle yarn or 18B would be false
twisted in the opposite direction to yarns 18A and 18C. It should be
recognized however that more than three yarns could be interlaced, in
fact as many as eight could be interlaced. Where more than three yarns
are interlaced, as previously indicated, alternate false-twis-t spindles
would be opera-ted in a reverse direction.
The following examples illustrate the nature and advantages of
the present invention.
EXAMP~E I
A comparison was made of the as-spun properties of a
conven-tional melt spun polypropylene having a broad Molecular Weight
30 Distribution = 12.1 and a low resin Melt Flow = 10-12 (Resin A); two
polypropylenes having a broad Molecular Weight Distribution = 12 and a
high resin Melt Flow = 30 and 44, (Resins E and K, respectively), a
polypropylene having a broad Molecular Weight Distribution = 12 and a low
resin Melt Flow = 3 (resin L) and a plurality of different resins having
narrow Molecular Weight Distributions (4.2 to 7.5) and high resin Melt
Flows (21 to 57). The letter designations in Table I indicate the
individual resins utilized. Runs 1 to 12, 19, 20, 22 and 25 utilized a
12x48 mil spinnerette with 325 mesh screen. Runs 1 to 12 utilized a spin
12
temperature of 293~C and runs 19, 20, 22 and 25 a spin temperature of
246C. Since some difficulties in spinning and quenching were
encountered and it appeared desirable to spin resin B at lower spin
speeds for comparison runs 13 through 18, 21, 23, 24 and 26 were spun at
254C spin temperature through a 32 hole - 0.012x0.048 inch spinnerette
and utilizing quench air at 80 ft/min. Some difficulties were again
experienced at spin speeds above 2400 me-ters/minute and runs 36 through
43 were spun through a spinnerette with 0.03.090 inch holes. Runs 44
through 57 were spun, utilizing a spinnerette having 0.12x0.048 inch
holes at a spin temperature of 312C. Runs 27 through 35 were run at a
spin temperature of 250C, a nominal godet speed (spin speed of 2500
meters/minute) and utilizing quench air at 80 ft/min. A finish herein
designated finish C as in Table V was applied to the collected filaments
at a rate of 1% by weight and comprised 8~.63% Nopcolube 2152P (a
trademark of Diamond Shamrock, Morristown, N.Y.), 13.32% ethoxylated
cetyl/stearyl alcohol (25 moles ethylene oxide per molecule) and 0.05%
of Givgard DXN (a Trademark of Givaudin Corp. of Clifton, N.J.) an
antimicrobial preservation agent. It is to be noted that the melt flow
listed in Table I is "melt spun melt flow" or the melt flow as measured
after melt spinning. Generally, the resin melt flow of relatively low
resin melt flow polymers will differ significantly from the melt spun
melt flow but with relatively high resin melt flow polymers in the melt
spun melt flow will not change appreciably.
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o
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Table l
.- Observation of the results set forth in Table I show that the
- narrow Molecular Weight Distribution - high Melt Flow resins exhibited a
number of improved properties, including low elongation, high
birefringence, high tenacity and low spun denier, particularly at high
spin speeds above about 1500 meters/minutes. From the properties shown
it is clear that the narrow Molecular Weight Distribution - high Melt
Flow products of the present invention can be utilized for numerous
commercial purposes in their as-spun condition without further treatment
or little additional treatment.
Since the largest volumes of samples at the full range of spin
speeds and the as-spun physical properties of yarns produced from Resin L
approached those of the preferred narrow Molecular Weight Distribution -
high Melt :Elow resins, samples of yarns produced in runs 44 through 57
were cold drawn without twisting to determine whether further treatment
would be beneficial. In these tests, the yarns were drawn at a speed of
314 meters/min., with 7 and 6-l/2 wraps about the feed rolls and the draw
rolls, respectively, and with temperatures of 80 and 125C on the feed
rolls and draw rolls, respectively.
The physical proper-ties of the drawn yarns are set forth in
Table II below.
16
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17
It is to be ohserved that improvement in properties required
cold drawing at high draw ratios.
Polymer B was melt spun using a 70 hole 0.020 x 0.020 inch hole
spinnerette and a 360 mesh screen in an effort to make yarn having a
total denier of 300. Quench air was 80 ft/min. A finish C was applied to
the yarn at a rate of 1% by weight and comprised 86.63% Nopcolube 2152P
(Diamond Shamrock, Morristown, N.J.) 13.32% Ethoxylated ce-tyl/stearyl
alcohol (25 moles ethy:lene oxide per molecule) and 0.05% Givgard DXN.
The yarns were also heat set for 5 hours at the temperature indicated.
These runs and the physical proper-ties of the yarn are set for-th in Table
III below.
TABLE III
Spin Heat Boiling
Run Speed Set Elon- Water Modulus
Sample m/min. Temp,F Denier Tenacity gation hrinka~ _ 5%
58-B 3500 None 298 2.3 166 14.7 17 12
59-B 3500 230 300 2.3 149 0.6 23 15
60-B 3500 270 299 1.8 115 0.9 18 12
61-B 2500 None~ 285 1.6 230 12.5 11
62-B 2500 230 285 2.0 178 0.5 19 12
63-B 2500 270 80-159 2.8 121 0.9 27 19
Run 63 is rather meaningless since the supply of polymer began
to run out at the end of the run. Also problems of lost filaments
occurred in the spinning at 3500 m/min. However, the data clearly
indicates that heat setting does reduce the elongation and shrinkage
significantly. In spite of the spinning problems at 3500 m/min. it can
also be seen that the higher speed (3500 m/min.) produces a yarn of
higher tenacity and lower elongation than spinning at the lower speed
(2500 m/min.).
In order to determine what effect false-twist draw~-texturing
during spinning would have on products of the present invention, three
polypropylenes were run under varying conditions of draw ratio and twist
ratios to produce 600, 700, 800 and 900 denier yarns from each polymer.
In these runs the polymers were each run on a 34 hole, 0.012x0.048 inch
hole spinnerette with a 325 mesh screen. A polymer pressure of 2000
psig, a spinning speed of 800 m/min. and a quench air rate of 80 ft/min.
were utilized in all runs. Polymer temperatures (C) at each of four
extruder zones and the polymer properties were as follows:
-- . ... . .
2~7iL~l
18
Polymer MWD Resin MF Zl Z2 Z3 Z4
C 5.0 21 205 235 25~ 250
- ~ 5.0 3~ 205 235 250 250
N 12 230 250 280 280
0.5% by weight of a finish, herein designated finish B as in Table V,
comprising a 10% emulsion of a reactive polysiloxane (Dow Corning 1111
Emulsion, sold by Dow Corning Corp.) was applied to the yarns.
A Scragg, 12 ceramic disc friction texturing machine was
utilized, with temperatures of 150C at bo-th the Eirst and second
heaters. Twist and contraction factor were measured on snatched samples.
Over-feed was 12% to the setting zone. Denier was calculated at the draw
roll using the formula:
Undrawn Denier
Draw Ratio
The speed of the draw roll was 297 m/min. at D/Y 1.56 and 272 m/min. at
D/Y 1.71.
Table IV below sets forth the results of these runs.
TABLE IV
DR=2.225 D/Y=1.56
20 Sample
Resin SD -l/t2 FD CF
66-N 600 64/g5 270 1.55 35
65-N 800 100/62 360 1.50 24
66-C 600 25/35 270 1.53 33
25 67-C 700 34/45 315 1.56 31
68-C 800 40/52 360 1.53 28
69-C 900 43/52 404 1.57 27
70-M 600 27/37 270 1.54 32
71-M 700 34/43 315 1.55 30
30 72-M 800 42/55 360 1.49 26
73-M 900 48/58 404 1.47 23
` DR=2.225 D/Y=1.71
74-N 600 66/36 270 1.58 35
75-C 600 27/27 270 1.51 34
35 76-C 800 40/43 360 1.46 28
77-M 600 28/25 270 1.63 36
7B-M 800 41/46 360 1.50 27
DR=2.407 D/Y=1.56
7g-N 600 65/45 Unable to snatch sample
40 80-C 600 26/40 249 1.55 36
81-C 800 41/56 332 1.50 29
82-M 600 31/55 249 1.45 34
83-N 800 41/59 332 1.48 29
DR=2.407 D/Y=1.71
45 84-N 600 64/44 249 1.68 33
85-C 600 29/36 249 1.62 35
. .
2~
19
86-C 80042/44 332 1.50 29
87-M 60030/38 249 1.56 36
88-M 80044/45 332 1.55 31
DR=2.622 D/Y=1.56
89-N 60060/48 229 1.60 38
90-C 60028/40 229 1.63 38
91-C 80041/55 305 1.54 32
92-M 60030/42 229 1.57 39
93-M 80043/62 305 1.54 32
DR=2.622 D/Y=1.71
94~M 60031/35 229 1.55 37
95-M 80046/51 305 1.51 31
DR=2.821 D/Y=1.71
96-M 60034/41 213 1.51 39
97-M 80049/63 284 1.49 33
DR=3.Q23 D/Y=1.71
98-M 60038/47 198 1.50 41
99-M 80048/62 265 1.46 34
DR=3.206 D/Y=1.71
100-M 60039/46 187 1.53 43
- 101-M 80052/65 250 1.47 35
DR=3.413 D/Y=1.71
102-M 60043/57 176 1.52 45
103-M 80051/63 234 1.56 38
Symbols above represent the following:
DR = Draw ratio
D/Y = Surface speed of discs/linear speed of yarn
SD = Spun Denier
tl = tension in grams as measured above false twist spindle
t2 = tension in grams as measured below false twist spindle
FD = Denier at draw roll ~ Undrawn Denier/Draw Ratio
CF = Contraction Factor - untwisted length/twisted leng-th
tpi = turns per inch
600 spun denier yarn of polymer N had broken Eilaments at a
draw ratio of 2.622 and D/Y of 1.56 and would not run at higher draw
ratios and D/Y's.
It was concluded during the above runs and from an analysis of
tne data, increased D/Y decreases t2 but has little effect on twist, the
low melt flow polymer did not run well under any conditions as compared
with -the high melt flow polymers and tpi is a function of denier and is
little affected by draw ratios, D/Y and tension.
Based on the good performance a~tained ln the previous tests,
~- polymer M was false-twist, draw-textured in a variety of colors to
produce 250 denier through the 34-hole spinnerette. All samples were
spun at 800 as-spun denier and at 800 m/minute. Draw-texturing condi-
tions were at a draw ratio of 3.413, D/Y of 1.71, 272 m/min., heater
temperatures of 150C and an overfeed across the second heater (to
setting zone) of 12%. Two different finishes, namely, the previously
described finishes B and C, were applied in some runs.
Table V lists the as-spun properties.
TABLE V
Run-Polymer Color Finish Denier Tenacity Elongation
104-M Natural C 798 1.4 504
105-F Natural C 807 1.1 615
106-M White C 804 1.4 541
107-M White B 804 1.4 541
108-M Lemon C 803 1.3 587
109-M Gold Leaf C 812 1.0 745
llO-M Gold Leaf B 812 1.0 745
lll-M Blaze Red C 807 1.0 717
112-M Spice Brown C 813 1.0 710
113-M Spice Brown B 813 1.0 710
114-M Velvet C 821 1.1 906
115-M Black C 814 1.2 609
116-M Black B 814 1.2 609
The properties of the finished yarns after draw-texturing are
set forth in Table VI.
TABLE VI
Run-Polymer ColorFinish _l/t2 CF tpi
104-M Natural C 52/70 1.49 36
105-F Natural C 37/50 1.50 37
106-M White C 39/48 1.54 39
107-M White B 44/30 1.54 39
108-M Lemon C 37/34 1.52 38
109-M Gold Leaf C 30/30 1.55 37
llO-M Gold Leaf B 30/28 1.61 40
lll-M Blaze Red C 29/22 1.60 38
112-M Spice Brown C 30/17 1.58 40
113-M Spice Brown B 32/28 -* -*
114-M Velvet C 30/17 1.58 39
115-M Black C 35/22 1.52 40
116-M Black B 38/26 1.51 40
*Yarn broke out
All samples in the above test spun without incident. However,
the yarns to which finish B was applied fused during texturing and the
yarn of run 113 broke out in attempting to snatch.
In order to prepare 3-ply yarns the spinning and false-twist
draw-texturing of the previous runs were repeated except for those
21
instances where finish B had been utilized. Operation of an entangler of
the type referred to in ~IGURE 3 was tried but found to produce too much
entanglement. Thereafter, an interlacer of the type specifically referred
to in the discussion of ~IGURE 11 was used with each position of the disc
type false-twisters all rotating in the same direction but the composite
yarn produced was of high torque. Finally, the last mentioned interlacer
was used with the false-twist positions alternating direction of twist
and the air to the interlacer or entangling ~et at 30 p9i. Two composite
yarns of three yarns each in accordance with the method described with
reference to FIGURE ll. This procedure eliminated the excess torque and
produced acceptable composite yarns.
Table VII sets forth the properties of the individual yarns and
the two composite yarns.
TABLE VII
Run
Polymer Color Denier Tenacity Elongation LSS*
117-M Natural 255 4.0 31 9.8
118-F Natural 261 3.0 38 13.3
ll9-M White 243 4.4 44 12.5
120-M Lemon 252 3.9 46 13.8
121-M Gold Leaf 255 2.8 63 9.6
122-M Blaze Red 251 3.0 73 12.0
123-M Spice Brown 248 2.3 27 9.6
124-M Velvet Brown 252 2.9 31 13.6
125-M Black 254 3.8 60 14.4
126 Composite
121-122-125 792 2.9 65 5.9
127 Composite
120-124-123 786 3.1 45 2.4
*LSS is the Leesona Skein Shrinkage Test
It was determined from the above data that the entangling
procedure utilized herein (entangling during spinning and prior to
windup) also increased the denier above what would theoretically be
expected by a conventional entangling procedure (entangling individual
garns after windup). It should be recognized that as many as 6 to 8
yarns could be similarly interlaced to produce composite yarns of 1500
to 2000 denier.
The composite yarns were also knit and woven into fabrics
without difficulty. The knit sample was boiled off and developed good
bulk and pleasing hand. The composite yarns could be used in hand knit
items, upholstery fabrics, etc.
This test was carried out to evaluate the Taslan texturing of
yarns produced in accordance with the present inven-tion which have been
2~
22
twisted but not drawn. Polymer B was spun at 2500 m/min. and in the
manner and under the same conditions as the previous example except that
it was wound at 40 grams tension. The yarn was twisted on a Single
Spindle Dienes Twister at 465 m/min., and 5500 rpm spindle speed to
produce 0.3 twist level. The properties of the untwisted and twisted
yarns are set forth in Table VIII below.
TABLE VIII
Run - Polymwe Condition Denier Tenacity Elongation Shrinka~e
10128 B Untwisted 312 2.0 284 8.9
B 0.3 Twist 303 1.9 246 9.3
This yarn, a twist-drawn yarn from polymer A and a core yarn
~rom polymer A were Taslan textured (a Trademark of E. I. du Pont de
Nemours and Co.) at a core feed rate of 187 m/min., an effective feed
rate of 337 m/min. and a take-up speed of 182 m/min. The yarn was also
run side-by-side wi-th a commercial yarn with the speed being the maximum
to get acceptable bonding with the core in the commercial yarn.
Inspection of the yarns indicated that the yarn of the present invention
tangled with the core yarn better than the commercial yarn.
In order to evaluate draw-Taslan texturing of the yarns of the
present invention a series of runs were made comparing yarns prepared
from Polymer C and from Polymer N at different spin speeds and in
diferent colors. A 34-hole, round, 0.015 x 0.019 inch spinnerette was
used. Spinning temperature (C) were 250C for polymer C and 292C
for polymer N.
The quench air rate was <80 ft/min. and 1.1% by weight of
finish B was applied. Table IX below sets forth the as-spun deniers
obtained.
TAB~E IX
Run - Polymer ColorSpin Speed Denier
129 C Blue 800 464
130 C Blue 800 399
131 C Blue 1100 404
132 C Blue 1100 349
35 133 C Blue 1500 351
: 134 C Blue 1500 301
13j C Blue 2200 252
136 N Blue 800 460
137 N Blue 800 400
40 l38 N Blue 1100 402
139 N Blue 1100 348
140 N Blue 1500 352
141 N Blue 1500 303
142 N Blue 2200 248
45 143 C Brown 800 460
144 C Brown 800 401
145 C Brown 1100 409
146 C Brown 1100 3S0
~r~
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23
147 C Brown 1500 352
148 C Brown 1500 300
149 C Brown 2200 252
Samples of Polymer C spun well at all speeds ~ut difficulties
were encountered in quenching Polymer N at 1500 and 2200 m/min. due to
-the presence of wild filaments.
- The yarns produced were then drawn on the apparatus of ~IGURE 2
under varied heat conditions during draw, namely, utilizing heated draw
rolls, cold draw rolls and a hot 10-inch plate operating at either 140C
or 120C, and cold draw rolls with no heating of any type. Drawing was
conducted at a speed of 800 m/min. and with 7 and 6-1/2 wraps around the
feed rolls and draw rolls, respectively. Table X sets forth the
properties of the yarns produced.
;~
24
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27
It is clear, from the results set forth in Table X that the
drawing efficiency (lack of broken filaments, etc.) is much better for
the narrow molecular weight distribution Polymer C than for the broad
molecular weight distribution (conventional) Polymer N, both with the
heated plate and with no heating. The actual draw was also higher for
Polymer C than for Polymer N and increased as draw tension decreased.
The color data shows a greater color effect on Polymer N, when it is
cold drawn, than on Polymer C. The hot plate and lower draw tensions
appear to improve the color differences of Polymer C samples. The
unusual result (low ~R) observed in run 142 when the sample of Polymer N
spun at 2200 m/min was cold drawn resulted from the sample continuing
to shrink after windup. In general, the low ~L values with cold draw
indicate that light color results, but this can be remedied by color
adjustments. Analysis of the above runs lead to the conclusion that
Polymer C can be cold drawn (with a hot plate) during spinning at 1400
to 1800 m/min. and at full extruder output (380#/hr) with only minimal
color adjustment.
- While specific examples and items of equipment have been set
forth herein7 it is to be understood that such recitations are illus-
trative only and are not to be limiting.
:
