AU643641B2 - A spinning process for producing high strength, high modulus, low shrinkage synthetic yarns - Google Patents

Abstract

A process for spinning an organic synthetic melt spinnable polymer is disclosed herein. The process includes the steps of: extruding the polymer through a spinneret (16); passing the filaments from the spinneret through an elongated zone (18); maintaining the filaments at a temperature above the glass transition temperature of the polymer within the zone; and thereafter converging the filaments. Alternatively, the process includes the steps of: extruding the polymer through a spinneret; providing an elongated zone having a length of at least 5 meters or means for controlling the temperature within said zone from a predetermined maximum to a predetermined minimum; passing the filaments through the zone; and thereafter converging the filaments. <IMAGE>

Description

nw P/00/011 PATENTS ACT 1952-1973 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE 643641 Class: Int. CI: Application Number: Lodged: f Complete Specification Lodged: Accepted: Published: Priority: Related Art:

I*

TO BE COMPLETED BY APPLICANT S Name of Applicant: Address of Applicant: Actual Inventor: HOECHST CELANESE CORPORATION, a corporation organized and existing under the laws of the State of Delaware Route 202-206 North Somerville, New Jersey, U.S.A.

F. HOLMES SIMONS RONALD L. GRIFFITH Address for Service: Cowie Carter Hendy Patent Trademark Attorneys 71 Queens Road MELBOURNE, 3004, Australia Complete Specification for the invention entitled: A SPINNING PROCESS FOR PRODUCING HIGH STRENGTH, HIGH MODULUS, LOW SHRINKAGE SYNTHETIC YARNS The following statement Is a full description of this Invention, Including the best method of performing It known to me:- 1 ,1 la A SPINNING PROCESS FOR PRODUCING HIGH STRENGTH, HIGH MODULUS, LOW SHRINKAGE SYNTHETIC YARNS This is a continuation of copending application Ser. No. 523,099 filed on 11 May 1990, now abandoned.

Field of the Invention The instant invention is directed to a spinning process for producing high strength, high modulus, low shrinkage synthetic yarns.

Background of the Invention Since fiber-forming, melt-spinnable, synthetic polymers were introduced, fiber manufacturers have looked for ways to increase the strength and stability properties of the fibers made from those polymers. The additional strength and stability properties of the fibers are needed so that applications beyond textile uses could be opened for their products. Such non-textile uses (also known as "industrial uses") include: tire cord; sewing thread; sail cloth; cloth, webs or mats used for road bed construction or other geo-textile applications; industrial belts; composite materials; architectural fabrics; reinforcement in hoses; laminated fabrics; ropes; and the like.

Originally, rayon was used in some of these industrial uses. Thereafter, nylon supplanted rayon as the material of choice. In the 1970's, conventional polyesters, 20 such as polyethylene terephthalate, were introduced into competition against nylon.

In about 1985, higher performance polyesters, i.e. higher strength and greater :stability, were introduced.

SN-786:3pc 7 September 1993 o A brief review of some of the patent prior art, summarized below, indicates that three general areas have been investigated as possible ways of enhancing the strength and stability properties of these synthetic fibers. Those general areas include: processes directed to drawing; processes directed to the polymer; and processes directed to the spinning. Hereinafter, the term "drawing" shall refer to the heating and stretching performed on an as-spun yarn. The term "treatment to the polymer" shall refer to those things done tc the polymer prior to spinning. The term "spinning" shall refer to processes for forming filaments from polymer, but excluding drawing.

f.

The processes directed to drawing are as follows:

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In U. S. Patent No. 3,090,997, multistage drawing of polyamides, for use as tire cords, is disclosed. The fibers (nylon) are melt-spun S in a conventional fashion. Thereafter, spun fibers are drawn in a i3 three-stage process (drawn, then heated, then drawn again) to obtain a drawn nylon having the following properties: tenacity ranging from 10.4 to 11.1 grams per denier (gpd); elongation ranging from 12.9 to S 17.1%; and initial modulus cf 48 to 71.gpd/100%.

In U. S. Patent No. 3,303,169, there is disclosed a single-stage drawing process for polyamides that yields high modulus, high tenacity, and low shrinkage polyamide yarns. The spun polyamide is drawn and heated to at least 1150C to obtain a yarn having: tenacity in the range of 5 to 8.7 gpd; elongation ranging from 16.2 to 30.3%; initial modulus of 28 to 59gpd/100%; and shrinkage ranging from 3.5 to In U. S. Patent No. 3,966,867, a two-stage drawing process for polyethylene terephthalate having a relative viscosity of 1.5 to 1.7 is disclosed. In the first stage, the fibers are subjected to a temperature between 70 and 100 0 C and a draw ratio of 3.8 to 4.2. In the second stage, the fibers are subjected to a temperature between 210 and 250 C and a draw ratio, in the aggregate of the first draw ratio and second draw ratio, in the range of 5.6 to 6.1. The drawn yarn obtained has the following properties: tenacity, 7.5 and gpd; elongation, approximately 2 to 5% at a load of 5 gpd; elongation

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at break, 9 to 15%; and shrinkage, 1 to 4%.

In U. S. Patent No. 4,003,974, polyethylene terephthalate spun yarn, having an HRV of 24 to 28, is heated to 75 to 250°C while being 4 49 1'3 drawn, is then passed over a heated draw roll, and finally relaxed.

The drawn yarn has the following properties: tenacity, 7.5 to 9 gpd; shrinkage, about elongation at break, 12 to 20%; and load bearing capacity of 3 to 5 gpd at 7% elongation.

Those processes directed to enhancing yarn properties by treatment to the polymer are as follows: In U. S. Patent Nos. 4,690,866 and 4,867,963, the intrinsic viscosity of the polyethylene terephthalate is greater than I I 0.90. In U. S. Patent No. 4,690,868, the as-spun (undrawn) fiber properties are as follows: elongation at break, 52 to 193%; birefriengence, 0.0626 to 0.136; and degree of crystallinity, 19.3 to 36.8%. The drawn fiber properties are as follows: tenacity, 5.9 to 8.3 gpd; elongation, 10.1 to 24.4%; and dry shrinkage (at 2100C), 0.5 to 10.3%. In U. S. Patent No. 4,867,936, the drawn fiber properties are follows: tenacity, about 8.5 gpd; elongation at break, about and shrinkage (at 177 0 about 5.7%.

Those processes directed to spinning are as follows: In U. S Patent No. 3,053,611, polyethylene terephthalate after leaving the spinneret is heated to 220 0 C in a spinning shaft two meters long. Thereafter, cold water is sprayed onto the fibers in a second shaft. The fibers are taken up at a speed of 1,600 meters per e minute (mpm) and are subsequently drawn to obtain a tenacity of gpd.

In U. S. Patent No. 3,291,880, a.polyamide is spun from a spinneret and then cooled to about 15°C, then the fiber is sprayed with live steam. The as-spun fiber has a low orientation and a low birefriengence.

In U. S. Patent No. 3,361,859, a synthetic organic polymer is spun into a fiber. As the fibers exit the spinneret, they are subjected to "controlled retarded cooling". This cooling is conducted over the first seven inches from the spinneret. At the top adjacent the spinneret), the temperature is 300°C and at the bottom approximately 7 inches from the spinneret), the minimum temperature is 1320C. The as-spun yarn has a low birefriengence (11 to 35 x 10 3 Pnd drawn yarn properties are as follows: tenacity, 6.9 to 9.4 gpd; initial modulus, 107 to 140 gpd/100%; and elongation at break, 7.7 to 9.9%.

In U. S. Patent Nos. 3,936,253 and 3,969,462, there is disclosed the use of a heated shroud (ranging in length from one-half foot to 4 4 two feet) with temperatures ranging from about 115 to 460 0 C. In the former, the temperature is greater at the top of the shroud than at the bottom. The drawn yarn properties of the former are as follows: tenacity, 9.25 gpd; elongation, about 13.5%; and shrinkage, about 4 In the latter, the temperature is constant within the shroud and the drawn yarn properties are as follows: tenacity, 8 to 11 gpd; and elongation at break, 12.5 to 13.2%.

In U. S. Patent No. 3,946,100, fibers are spun rom a spinneret 5* 0 and solidified at a temperature below 80°C. The solidified fibers are then reheated to a temperature between the polymer's glass transition temperature (Tg) and its melting temperature. This heated fiber is withdrawn from the heating zone at a rate of between 1,000 to 6,000 meters per minute. Spun yarn properties are as follows: tenacity, 3.7 to 4.0 gpd; initial modulus, 70 to 76 gpd/100%; and birefriengence, 0.1188 to 0.1240.

In U.S. Patent No. 4,491,657, polyester multifilament yarn is melt-spun at high speed and solidified. Solidification occurs in a zone comprising, in series, a heating zone and a cooling zone. The heating zone is a barrel shaped heater (temperature ranging from the polymer's melting temperature to 4000C) ranging in length from 0.2 to meters. The cooling zone is cooled by air at 100 to 40°C. Drawn yarn made by this process has the following properties: initial modulus, 90 130 gpd; and shrinkage (at 1500C) less than 8.7%.

e S* In U. S. Patent No. 4,702,871, fiber is spun into a chamber ?0 having a subatmospheric pressure. Spun yarn properties are as follows: strength, 3.7 to 4.4 gpd; birefriengence, 104.4 to 125.8 (x 10 and dry heat contraction, 4.2 to 5.9% at 160°C for 15 minutes.

In U. S. Patent No. 4,869,958, the fiber is spun in the absence of heat and then taken up. At this point, the fiber has a low degree

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1 of crystallinity, but it is highly oriented. Thereafter, the fiber is heat treated. The drawn fiber properties are as follows: tenacity, 4.9 to 5.2 gpd; initial modulus, 92.5 to 96.6 gpd/100%; and elongation, 28.5 to 32.5%.

5* The foregoing review of patents indicates that while some of the fibers produced by these various processes have high strength or low shrinkage properties, none of the foregoing patents teach of a yarn or a process for producing such a drawn yarn having the combination of high tenacity, high initial modulus, and low shrinkage.

The patents which come closest to teaching such a drawn yarn are U. S. Patent Nos. 4,101,525 and 4,195,052, related patents that are assigned to the assignee of the instant invention. In these patents, the polyester filaments (the polymer having an intrinsic viscosity of to 2.0 deciliters per gram) are melt spun from a spinneret. Molten filaments are passed through a solidification zone where they are uniformly quenched and transformed into solid fibers. The solid fibers are drawn from the solidification zone under a substantial stress (0.015 to 0.15 gpd). These as-spun solid fibers exhibit a relatively high birefriengence (about 9 to 70 x 10-3). The as-spun fibers are then drawn and subsequently heat treated. The drawn S filament properties are as follows: tenacity, 7.5 to 10 gpd; initial modulus, 110 to 150 gpd/100%; and shrinkage, less than 8.5% in air at 175 C.

Summary of the Invention S A process for spinning an organic synthetic melt spinnable polymer is disclosed herein. The process includes the steps of: extruding the polymer through a spinneret; passing the filaments from the spinneret through an elongated zone; maintaining the filaments at .0L a temperature above the glass transition temperature of the polymer over a distance of about 3 meters or greater within the zone; and thereafter converging the filaments.

Alternatively, the process includes the steps of: extruding the polymer through a spinneret; providing an elongated zone having a length of at least 5 meters or means for controlling the temperature within said zone from a predetermined maximum to a predetermined minimum; passing the filaments through the zone; and thereafter converging the filaments.

Description of the Drawing For the purpose of illustrating the invention, there is shown in the drawing a schematic of the process which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangement and instrumentalities shown.

9* So Figure 1 is a schematic elevational view of the spinning process.

Figure 2 is a schematic elevational view of the drawing process.

Detailed Description of the Invention High tenacity, high initial modulus, and low shrinkage drawn yarns and the process by which such yarns are spun are discussed hereinafter. The term "yarn" or "filament" or "fiber" shall refer to any fiber made from a melt spinnable synthetic organic polymer. Such polymers may include, but aro not limited to, polyesters and 0 polyamides. The invention, however, has particular relevance to polyesters such as, for example, polyethylene terephthalate (PET), blends of PET and polybutylene terephthalate (PBT), and PET cross-linked with multifunctional monomers pentaerithritol). Any of the foregoing polymers may include conventional additives. The yarn I.V. (for PET based polymer) may be between 0.60 and 0.87. The instant invention, however, is not dependent upon the intrinsic viscosity of the polymer.

Referring to Figure 1, a spinning apparatus 10 is illustrated. A conventional extruder 12 for melting polymer chip is in fluid communication with a conventional spinning beam 14. Within spinning beam 14, there is a conventional spinning pack 16. Pack 16 may be of an annular design and it filters the polymer by passing the polymer S through a :ed of finely divided particles, as is well known in the ,o art. Included as part of the pack 16 is a conventional spinneret (not 10* shown). Flow rates of polymers through the pack may range from about 10 to 55 pounds per hour. The upper limit of 55 pounds is defined e only by the physical dimensions of the pack 16 and greater flow rates may be obtained by the use of larger packs. The spun denier per S filament (dpf) ranges from 3 to 20; it being found that the optimum Is.. properties and mechanical qualities for the yarn appear between 5 and *5 4 13 dpf.

069 Optionally, the fiber, as it leaves the spinneret, may be quenched with a hot inert gas air). See U. S. Patent No.

4,378,325 which is incorporated herein by reference. Typically, the gas is about 230°C and is provided at about six standard cubic feet per minute (scfm). If the air is too hot, i.e. over 260 0 C, the spun yarn properties are significantly deteriorated.

Immediately below and snugly airtight) mounted to spinning beam 14 is an elongated column 18. The column comprises an insulated tube having a length of about 5 meters or greater. Column length will be discussed in greater detail below. The tube's internal diameter is sufficiently large twelve inches) so that all filaments from the spinneret may pass the length of the tube without obstruction. The column is equipped with a plurality of conventional band heaters so that the temperature within the tube can be controlled along its length. Column temperatures will be discussed in greater detail below. The column is, preferably, subdivided into a number of discrete temperature zones for the purpose of better temperature 1 control. A total of 4 to 7 zones have been used. Optionally, the S column 18 may include an air sparger 17 that is used to control temperature in the column. Sparger 17 is designed to evenly **4 distribute an inert gas around the circumference of the column.

Inside the bottom-most end of the column 18 is a perforated, truncated cone 19, i.e. a means for reducing air turbulence. The cone 19, which is preferably three feet in length and having a diameter co-extensive with the tube diameter at its uppermost end and a diameter of about one half that at the bottom end, is used to exhaust air, via a valved exhaust port 21, from the bottom-most end of ;a is tube so that movement in the thread line, due to air turbulence, is substantially reduced or eliminated completely.

Below the bottom-most end of the column, the thread line is conerged. This convergence may be accomplished by a finish applicator 20. This is the first contact the yarn encounters after leaving the spinneret.

The length of the column, non-convergence of the individual filaments, and the air temperature profile w the column are of particular importance to the instant invention. With regard to the temperature profile, it is chosen so that the fibers are maintained at a temperature above their Tg over a significant length of the column at least 3 meters). This temperature could be maintained over the entire length of the column, but the wound filaments would be unstable. Therefore, for practical reasons, the temperature within S the column is reduced to below the Tg, so that the filaments will S undergo no further changes in crystal structure before being wound up.

*1 Preferably, the temperature profile is chosen to reflect the 0. temperature profile that would be established within the tube if no external heat was applied. However, the "no external heat' situation is impractical because of numerous variables that influence the column temperature. So, the temperature profile is controlled, preferably in 0 a linear fashion, to eliminate temperature as a variable in the process.

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The air temperature within the column is controlled by the use of the band heaters. Preferably, the column is divided into a plurality *S of sections and the air temperature in each section is controlled to a predetermined value. Thus, the temperature within the column can be varied over the length of the column. The temperature within the column may range from as high as the polymer spinning temperature to at or below the glass transition (Tg) temperature of the polymer (Tg for polyester is about 80oC). The polymer spinning temperature occurs around the spinneret, i.e. as the molten polymer exits the spinneret.

However, air temperatures within the column are preferably controlled from about 155 C to about 50 C. At wind-up speeds less than 14,000 feet per minute, the first section adjacent the spinneret is preferably controlled to a temperature of about 155 C and the section furthest from the spinneret is tontrolled to about 50 C.

However, a linear temperature profile is not the only temperature pattern that will yield the beneficial results disclosed herein. At take-up (or wind-up) speeds greater than 14,000 fpm (4,300 mpm), the .1t. temperature profile (when the column is divided into four discrete 8e zones) may be as follows: (starting from the spinneret down) the first zone about 105 0 C to about 1100C; the second zone about 1100C to about 115 0 C; the third zone about 1250 to about 1300C; apd the fourth zone 115 0 C to about 120 0

C.

a* X: With regard to column length, a minimum column length of five 0 meters (with column temperature over the polymer's Tg for at least 3 meters) with filament convergence thereafter appears to be necessary for the instant invention. Column lengths between five and nine meters are suitable for the invention. The upper limit of nine meters is a practical limit and may be increased, room permitting. To optimize the tenacity pr6perties, a column length of about seven meters is preferred.

The fibers are converged after exiting the column 18. This convergence may be accomplished by use of a finish applicator.

Following the first application of the finish at finish applicator 20), the yarn is taken around a pair of godet rolls 22.

Thereafter, a second application of finish may be made at finish applicator 23). The first finish application may be made to reduce static electricity built up on the fibers. But this finish is sometimes thrown off as the fibers pass over the godet rolls. Thus, the finish may be reapplied after the godet rolls.

The fibers are then passed onto a conventional tension control *e winder 24. The wind-up speed is typically greater than 3,000 mpm l (9,800 fpm) with a maximum speed of 5,800 mpm (19,000 fpm). An optimum range exists of about 10,500 to 13,500 fpm (about 3,200-4,100 i: mpm). The most preferred range exists between about 3200 and 3800 mpm (10,500 and 12,500 fpm). At speeds below 9,800 fpm (3,000 mpm), the yarn uniformity properties deteriorate.

i ,le* The as spun polyester yarn produced by the foregoing process may be generally characterized as having relatively small crystals and a Oak,* relatively high orientation. It is believed that these qualities of the as spun yarn enuble the attainment of the unique drawn yarn properties discussed below.

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To quantify the general characterization of the as spun polyester yarn, the small crystals are defined in terms of crystal size (measured in i) and orientation is defined in one of the following terms: optical birefringence; amorphous birefringence; or crystal birefringence. Additionally, the spun polyester yarn is characterized in term of crystal size and long period spacing (the distance between crystals). In broad terms, the as spun polyester yarn may be characterized as having a crystal size less than 55A and either an optical birefringence greater than 0.090 or an amorphous birefringence greater than 0.060 or a long period spacing of less than 300A. More preferred, the as spun polyester yarn may be characterized as having a crystal size ranging from about 20 to about 551 and either an optical birefringence ranging from about 0.090 to about 0.140 or an amorphous 1 birefringence ranging from about 0.060 to about 0.100 or a long period spacing ranging from about 100 to about 250A. Most preferred, the as spun polyester yarn may be characterized as having a crystal size ranging from about 43 to about 54A and either an optical birefringence ranging from about 0.100 to about 0.130 or an amorphous birefringence ranging from about 0.060 to about 0.085 or a long period spacing ranging from about 140 to about 200A.

O* As will be apparent to +Lose of ordinary skill in the art, the crystal size of the spun yarr is about 1/3 that of conventional yarns in the optimum wind-up speed, range. The crystal size increases with speed, but it still remains low. The spun amorphous orientation is a 9 very high, about twice normal. This spun yarn has such a high orientation and low shrinkage, that it could be used without any drawing.

In addition, the spun polyester yarn has the following properties: a crystal content crystallinity level as determined by density) of 10 to 43%; a spun tenacity of about 1.7 to 5.0 gpd; a spun modulus in the range of 10 to 140 gpd/100%; a hot air shrinkage of about 5 to 45%; and an elongation of 50-160%.

Thereafter, the spun yarn is drawn. Refer to Figure 2. Either a one or two stage drawing operation may be used. However, it has been determined that a second stage offers little-to-no additional benefit.

°0 It is possible that the spinning operation may be coupled directly to a drawing operation spin/draw process).

S The as-spun yarn may be fed from a creel 30 onto a feed roll 34 that may be heated from ambient temperatures up to about 150°C.

Thereafter, the fiber is fed onto a draw roll 38 which may be heated from ambient temperatures to approximately 255°C. If heated rolls are not available, a hot plate 36, which may be heated from 180 2450 may be used. The hot plate 36 (having a six inch curved contact surface) is placed in the draw zone, between feed roll 34 and draw roll 38. The draw speed ranges from 75 to 300 meters per minute.

a The typical draw ratio is about 1.65 (for spun yarn made at about 3,800 meters per minute). The optimum feed roll temperature, giving the highest tensile strength, was found to be about 90 0 C. The optimum draw roll temperature is about 245 C. If the hot plate is used, the optimum temperature is between about 2400 245 C. The draw roll temperature gives some control over hot air shrinkage. In general, low shrinkages are desirable as they give rise to the best treated cord stability ratings. However, at least one end use, sail cloth, requires higher drawn yarn shrinkages and these can be controlled with lower draw roll temperatures.

Based on the foregoing, the drawn fiber properties may be controlled as follows: Tenacity may range from 4.0 to 10.8 grams per denier. The elongation may range from 7% to approximately 80%. The initial secant modulus may range from 60 to 170 gpd/100%. The hot air 0.

shrinkage (at 177 C) is 6% to 15%. The denier of the fiber bundle may range from 125 to 1100 (the latter number may be obtained by plying tows together) and the denier per filament ranges from 1.5 to 6 dpf. Such a yarn could be used as the fibrous reinforcement of a rubber tire.

Polyester PET) drawn yarns, made according to the process described above, can obtain an initial secant modulus greater than 150 grams per denier/100. Moreover, those yarns may also have a shrinkage of less than or those yarns may have a tenacity of greater than grams per denier.

a Another preferred embodiment of the drawn polyester yarn may be characterized as follows: a tenacity of at least 8.5 grams per denier; an initial modulus of at least 150 grams per denier/100%, and a shrinkage of less than Another preferred embodiment of the drawn polyester yarn may be characterized as follows: a tenacity of at least grams per denier; an initial modulus of at least 120 grams per denier/100%; and a shrinkage of less than Yet another preferred embodiment of the drawn polyester yarn may be characterized as follows: a tenacity ranging from about 9 to about 9.5 grams per denier; an initial modulus ranging from about 150 to about 158 grams per denier/100%; and a shrinkage less than Any drawn yarn, made according to the above described process, may be utilized in the following end uses: tire cord, sewing thread; sail cloth; cloth, webs or mats used in road bed construction or other 9 geo-textile applications; industrial belts; composite materials; architectural fabrics; reinforcement in hoses; laminated fabrics; ropes; etc.

The following critical tests, which are used in the foregoing S discussion of the invention and the subsequent examples, were performed as follows: Tenacity refers to the "breaking tenacity" as defined in ASTM D-2256-80.

6e Initial modulus (or "initial secant modulus") is defined per ASTM D-2256-80, Section 10.3, except that the line representing the initial straight line portions of the stress-strain curve is specified as a secant line passing through the 0.5% and 1.0% elongation points on the stress-strain curve.

All other tensile properties are as defined in ASTM D-2256-80.

Shrinkage (HAS) is defined as the linear shrinkage in a hot air environment maintained at 177+1 C per ASTM D-885-85.

Density, crystal size, long period spacing, birefringence, and S amorphous birefringence are the same as set forth in U.S. Patent No.

4,134,882 which is incorporated herein by reference. Specifically, each of the foregoing may be found in U.S. Patent No. 4,134,882 at or about: density column 8, line 60; crystal size column 9, line 6; long period spacing column 7, line 62; crystal birefringence i column 11, line 12; and amorphous birefringence column 11, line 27.

**4 Birefringence (optical birefringence or An) is as set forth in U.S. Patent No. 4,101,525 at column 5, lines 4-46. U.S. Patent No.

4,101,525 is incorporated herein by reference. "Bi CV" is the coefficient of variation of optical birefringence between filaments calculated from 10 measured filaments.

Other tests referred to herein are performed by convent.onal I methods.

Reference should now be made to the Examples which will more fully illustrate the instant invention.

Example I In the following set of experimental runs, a conventional polyester polymer (PET, IV-0.63) was spun. The spinning speeds were increased from 12,500 fpm to 19,000 fpm. The column length was 6.4 meters and divided into four temperature control zones. The temperature was controlled by measuring the air temperature close to the wall at the center of each zone. The polymer was extruded at a rate of 22.9 pounds per hour through a spinning beam at 285 C and a hole spinneret (hole size 0.009 inches by 0.013 inches). The fibers 4 0 were not quenched. The spun fibers were not drawn, but they were heat :O set. The results are set forth in TABLE I.

See*: s* S p TABLE I No. I No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 8B 0 0 0 04 0 0 Spin Speed, fpm 1: Col Top, °C Temp. 2nd, °C 3rd, °C Bottom, °C Denier dpf "True Stress" at Break gpd Spun: Denier Tenacity, gpd W. ,gpd/100% HAS, %-350°F Uster, 'U .Finish, 2,0, •IV Cryst 3 Au x 10 BiCV Density, gms/cc Yield Point Tenacity, gpd Heat-Set: Denier 006 4 WTenacity, gpd Elon, I.4. ,gpd/100% HAS, %-350-F 2,500 310 105 131 109 340 8.5 6.51 340 3.93 65.7 31.8 54.0 6.0 .96 .098 .623 34.2 108 3.2 1.3728 13,500 108 104 130 107 310 7.8 6.41 316 3.89 64.8 31.3 56.4 6.5 1.29 .358 .630 35.3 106 4.3 1.3742 14,500 105 104 129 105 290 7.2 6.55 289 4.10 59.8 31.7 52.1 7.0 1.14 .119 629 37.2 115 6.5 1.3766 15,500 104 107 132 i1 270 6.8 6.65 270 4.18 59.2 32.3 59.2 7.5 1.28 .168 .631 39.0 112 5.8 1.3788 16 ,500 105 109 132 i1 255 6.4 7.23 254 4.55 59.0 34.9 65.4 7.2 1.33 .263 .630 40.3 118 4.7 1.3804 1.57 252 4.33 49.5 30.5 68.8 3.0 56.9 150 7.0 1.401] 17,500 105 110 132 ill 240 6.0 18,500 106 106 130 109 225 5.6 6.98 240 4.52 54.5 33.4 60.1 7.5 1.59 .037 .629 42.2 124 6.7 6.86 228 4.57 50.0 32.3 66.6 7.0 1.34 .160 .626 43.2 127 6.9 7.14 222 4.71 51.6 33.8 76.2 7,2 1.52 .267 .627 43.3 130 J.4 19,000 105 110 133 119 220 1.3827 1.3840 1.3841

@B

1.18 1.26 1.38 1.48 338 308 287 271 4.06 4.19 4.26 4.34 62.3 58.6 53.2 51.0 32.0 32.1 31.1 31.0 60.2 62.2 66.3 70.0 2.0 2.2 2.8 2.8 55.7 55.9 56.6 56.9 152 142 143 145 5.8 7.9 7.9 6.3 1.3996 1.3999 1.4007 1.4011 0.89 0.97 1.04 1.11 1.67 240 4.46 46.6 30.5 64.0 3.2 57,0 146 6.5 1.75 226 4.65 44.4 31.0 73.2 3.0 57.3 156 9.1 1, 231 4.64 45.1 31.2 72.6 57.2 160 6.3 1.4015 Crys: 3 An x 10 BiCV Density,gms/cc Yield Point Tenacity, gpd 1.4013 1.4016 1.19 1.25 1.33 1.30 Example II In the following set of experimental runs, a conventional polyester (PET, IV-0.63) was spun. The cclumn temperatures were varied as indicated (air temperature, center of zones). The column length was 6.4 meters. The polymer was extruded at a rate of 23.1 pounds per hour through a spinning beam at 300°C and a 72 hole spinneret (hole size 0.009 inches by 0.012 inches). The fibers were not quenched. The spun fibers were subsequently drawn (as indicated).

The results are set forth in TABLE II.

TABLE II No. 1 No. 4 No. 5 No. 2 No. 3 No. 6 No. 7 it .1 «f 9 *04 0 oe4 4 4*

S

6b *i *p Spin Speed-fpm-1000's 10.5 Hot Quench-scfm/*C 6/2300 Air Bleed*-scfm/°C 30/35° Col. Temp Top *C 2nd *C 83 3rd °C Bottom *C 62 10.5 10.5 12.5 12.5 12.5 12.5 Spun: Denier Tenacity-gpd Elong-% I.M.-gpd/100% HAS-% 350°F Uster-% Finish-%

IV

An x 10 Cryst.

Max Draw Ratio Denier Tenacity-gpd Elong-% I.M.-gpd/100% HAS-% 350°F Max D.R. .03 Denier 370 2.87 122 63 65.5 1.38 1.82 .63 78 11.0 1.70 224 5.60 18.4 92 6.2 1.65 230 5.34 19.9 82 6.0 367 3.68 81.8 93 27.2 1.14 .44 .64 115 17.9 1.80 210 8.72 8.9 137 10.0 1.77 214 8.30 9.3 120 9.8 369 3.77 83.2 93 41.0 1.41 .74 .64 113 16.6 1.80 213 8.63 8.6 133 9.8- 1.77 217 8.72 9.2 137 10.0 344 3.50 82.6 86 49.5 .99 .96 .64 105 14.8 1.60 218 7.31 11.0 127 9.2 1.54 227 7.04 13.1 123 9.0 342 3.72 79.6 86 42.0 1.13 .85 .64 111 15.9 1.57 227 7.04 11.6 110 7.8 1.54 231 7.09 13.1 107 7.8 342 3.86 70.9 73 11.2 1.23 .50 .64 107 20,5 1.77 202 8.74 7.5 146 10.0 1.74 205 8,61 7.7 145 10.2 342 3.75 69,0 2.29 .54 .64 106 24.7 1.74 206 8.67 8.1 140 10.0 1.72 205 8.31 7.6 124 10.0 Soo Tenacity-gpd Elong-% lM.-gpd/100% HAS-% 350°F *Air sparger, item 17, Figure 1 In the above set of experimental runs those set forth in TABLE 11), Nos. 4, 5f 6 and 7 represent the instant invention.

Example III In the following sets of experimental runs, conventional polyester (PET, IV-0.63) was spun. The fibers were wound up at a rate of 10,500 fpm. The polymer was extruded at a rate of 19.5 pounds per hour through a 72 hole spinneret (hole size 0.009 inches by 0.012 to. inches) and a spinning beam at 300 0 C. The fibers were quenched with 6.5 s.,fm air at 2320C. The column was 6.4 meters long and divided lo* into 4 sections having the following air temperature profile (in .0.0 0 00 descending order): 135 C; 111 C; 92 C; and 830C at the center of the zones. The spun yarn had the following properties: denier 334; tenacity 4.09 gpd; elongation 71.7%; initial modulus 55.0 gpd/l00%; hot air shrinkage 11.8% at 350 Uster 1.10; I.V.

Fvote 035% 1 -0.647; FY- 0,5;birefringence -110 x 10- and crystallinity- VA 0. 1.6%.

In TABLE IIIA, the affect of draw ratio on drawn yarn properties is illustrated.

TABLE IIIA Draw Ratio 1.65 1.60 1.54 Denier 209 218 226 Tenacity gpd 8.15 7.53 7.12 Elongation 8.4 8.9 10.4 initial Modulus qpd/100 123 115 115 Hot Air Shrinkage %-350 F 12.0 12.4 12.0 22

J

In Table IIIB, the effect of the heating method during stretching is illustrated (the draw ratio was 1.65 and the yarn was not relaxed).

.ee 44, 0 0S 253~ Denier Tenacity gpd 334 4.09 209 8.15 214 6.67 212 8.05 209 8.05 211 8.45 211 7.96 211 8.18 Elongation 71.7 8.4 9.2 9.3 9,0 9.1 8.8 9.2 TABLE IIIB Hot Air Initial Shrinkage Modulus 350 F gpd/100% 55 11.8 123 12.0 95 19.0 86 8.0 93 9.0 110 9.2 110 9.2 108 9.2 Feed Roll Tem.

0°

C

Amb 78 78 78 78 100 120 Hot Plate Temn.

0°

C

(As Spun) 245 Amb 245 Amb 245 245 245 Draw Roll Temp.

0°

C

Amb Amb Amb 200 200 200 200 In Table IIIC, the effect of higher drawing temperatures and draw ratios is illustrated (the feed roll is at ambient temperature and the 0 draw roll is at 240 C).

Draw Ratio Denier Tenacity gpd EloT gation %0 Hot Air Shrinkage %-350 F 1.76 195 9.50 6,1 6.8 TABLE IIIC 1.72 194 9,22 6.1 7.0 1.70 199 8.89 6.3 6.8 1.67 203 8.73 6,7 6.5 1.64 209 7.76 6,6 6.8 1.61 208 6,71 Example IV In the following set of experimental runs, a conventional polyester (PET, IV-0.92) was spun. In runs Nos. 1-5, the fibers were spun and drawn in accordance with the methods set forth in U. S.

Patent Nos. 4,101,525 and 4,195,052. Nos. 6-9 were made as follows: PET with a molecular weight characterized by an I.V. of 0.92 was dried to a moisture level of 0.001% or less. This polymer was melted and heated to a temperature of 295°C in an extruder and subsequently forwarded to a spinn.ng pack by a metering pump. This pack was of an annular design, and provided filtration of the polymer by passing it through a bed of finely divided metal particles. After filtration the polymer was extruded through an 80 hole spinneret. Each spinneret hole had a round cross section with a diameter of 0.457 mm and a capillary length of 0.610 mm.

An insulated heated tube 9 meters in length was mounted snugly #9 below the pack and the multifilament spinning threadline passed through the entire length of this tube before being converged or coming into contact with any guide surfaces. The tube was divided down its length into seven zones for the purposes of temperature control. Individual controllers were used to set the air temperature at the center of each of these zones. Using a combination of process heat and the external heaters around the tube, individual controller settings were selected to arrive at a uniform air temperature profile down the vertical distance of this tube. In a typical situation the ,0 air temperature was 1550C at the top zone of the tube and the temperature was reduced in an approximately uniform gradient to 50 C at the bottom.

Approximately 10 cm below the tube the threadline was brought into contact with a finish applicator which also served as the convergence guide and the first contact that the yarn encountered. At the exit of the tube the cross section of the un-converged yarn was very small due to the proximity of the finish guide. This permitted a very small aperture to be used, thus minimizing the amount of hot air lost from the tube.

Following the application of spin finish the yarn was taken to a pair of godet rolls and then to a tension controlled winder. Wind up speeds were typically in the range 3200 4100 mpm.

Drawing of this yarn was effected in a second step, in which the IVb as spun yarn was passed over one set of pretension rolls to a heated feed roll maintained at a temperature set between 80 and 150 C. The yarn was then drawn between these rolls and a set of draw rolls maintained at a set point chosen in the range 180 to 255 0 C. A typical draw ratio for a spun yarn made at 3800 mpm would be 1.65, with samples spun at higher and lower speeds requiring lower or higher draw ratios, respectively.

The results are set forth in TABLE IV.

TABLE IV 0 Feed Roll Temperature C initial Initial Tenacity modulus Drawn Yarn Tenacity Mo jLus Drawn Yarn qd gp/100% Shrinkage X g pd/100 Shrinkage Spi ming Spun Yarn 350°F 350*F Speed Birefringence NO_. ofpm) xl 0'+3 1 5000 21.9 7.94 115.00 7.30 5.96 78.00 5.30 2 6000 30.1 7.85 118.00 7.00 6.90 103.00 6.70 3 7000 45.2 8.36 120.00 7.00 7.21 108.00 6.50 4 8000 60.5 8.51 130.00 7.80 7.31 113.00 6.00 5 5 9000 78 8.56 122.00 6.80 7.67 110.00 6.00 15 6 10500 10!. 9.52 158.00 7.50 10.94 173.00 7.30 a 60 7 11500 115 9.03 150.00 6.80 9.52 152.00 7.00 8 12500 121 9.08 152.00 7.50 9.53 160.00 7.30 9 13500 119 9.32 154.00 6.00 9.58 161.00 6.70 53 EYAMPLE V Polyester with a molecular weight characterized by an I.V. of 0.92 was dried to a moisture level of 0.001%. This polymer was melted a0 and heated to a temperature of 295 C in an extruder and the melt 0*09 subsequently forwarded to a spinning pack by a metering pump. After filtration in a bed of finely divided metal particles, the polymer was extruded through an 80 hole spinneret. Each spinneret hole had a diameter of 0.457 mm and a capillary length of 0.610 mm. On extrusion the measured I.V. of this polymer was 0.84.

The extruded polymer was spun into heated cylindrical cavity 9 meters in length. An approximately linear temperature profile (gradient) was maintained over the length of this tube. At the center of the top zone the air temperature was 1550C and at the bottom of the tube this temperature was 50 C. The multifilament yarn bundle was not converged until it came in contact with a finish guide just below the exit of the heated tube. From this point the yarn was advanced by a pair of godet rolls to a tension controlled winder. Under these conditions a series of four spun yarns were made at different spinning (wind-up) speeds. These yarns are referred to as examples A through D in Table V. A.

In another series of experiments the heated tube was shortened by taking out some of its removable sections. Examples E and F in Table V. A were spun through 7 and 5 meter columns. Other polymers with different molecular weights were also spun on this system to s give Examples G and H. Example I in Table VA illustrates a case in which lower column temperatures were used. In this case a linear gradient from 1250C to 50 C was established down the column.

0 All spun yarns in the series A through I were drawn in a single stage process using an ambient feed roll and a 245°C draw roll.

In a further series of tests the -same spun yarn which was described in Example A was drawn using different feed roll Stemperatures. The results from testing these yarns are given in Examples A, J and K in Table V. B.

TABLE V. A Spinning Conds Spin Temp ExamDie Lenzth Soeed °C mpm A 9 3200 155 B 9 3500 155 C 9 3800 155 D 9 4100 155 E 7 3200 155 F 5 3200 155 G 9 3200 155 H 9 3200 155 1 9 4100 125 Spun SPun Yarn IV Bir Crvst 0.84 .104 30.5 0.84 .115 34.4 0.84 .121 35.9 0.84 .119 38.9 0.84 .101 30,1 0.84 .073 25.0 0.76 .110 34.0 0.66 .102 22.9 0.84 .120 31.9 a e 0* 0 Draw Drawn Yarn Ratio Ten I.M. HAS gpd gpd/100% %-350°F 1.89 9.52 158 1.79 9.03 150 6.8 1.74 9.08 152 1.72 9.32 154 1.79 8.99 142 7.3 1.98 9.52 159 1.65 8.63 123 1.57 7.25 110 1.53 7.34 116 5.3 Drawn Hot Air I Modulus Shrink gpd/100% %-350*F 158 173 7.7 158 7.4 Feed Roll Examvle Temp °C Draw Ratio 1.89 1.82 1.87 TABLE V. B Drawn Tenacity gpd 9.52 10.94 10.30 EXAMPLE VI In the following experimental run, a conventional polymer, nylon, -207% was spun according to the inventive process and compared to nylon made by conventional processes.

oo.0 The nylon made by the inventive process was spun under the following conditions: throughput- 37 lbs. per hour; spinning speed- 2,362 fpm; denier 3500; number of filaments 68; spun relative viscosity 3.21 (H 2

SO

4 or 68.4 (HCOOH equiv.) quench air 72 scfm; winding tension 80g; column length 24 ft; column temperature top 240 0 C and bottom 48 0 C. The as-spun properties of this yarn were as follows: tenacity 0.95 gpd; elongation 235%; TE 1 2 14.6.

Thereafter the yarn was drawn under the following conditions: draw ratio 3.03; draw temperature 900C. The drawn yarn properties are as follows: tenacity 6.2 gpd; elongation TE 1 2 52; 10% modulus 0.87 gpd; hot air shrinkage (HAS) at 400°F 1.4%.

9C 9 a..

C..

*i 0 4)o

I

C ri em.

a o 20 One comparative nylon was spun in the following conventional fashion: throughput 23.4 lbs. per hour; spinning speed 843 fpm; denier 5556; number of filaments 180; spun relative viscosity 3.3 (H 2

SO

4 or 72.1 (HCOOH equiv.); quench 150 scfm. Thereafter, the yarn was drawn under the following conditions: Draw ratio 2.01; draw temperature 90 C. The drawn yarn properties are as follows: tenacity 3.8 gpd; elongation 89%; TE 1 2 33; 10% modulus .55 gpd.

Another comparative yarn was spun in the following conventional fashion: throughput 57.5 lbs. per hour; spinning speed 1048 fpm; denier 12400; number of filaments 240; spun relative viscosity 42 (HCOOH equiv.); quench air 150 scfm. Thereafter, the yarn was drawn under the following conditions: draw ratio 3.60; draw temperature 11 0C. The drawn yarn properties are s follows: tenacity 3.6 gpd; elongation 70%; TE 1 2 30.1; modulus at elongation 0.8 gpd; HAS (at 4000F) EXAMPLE VII In the following experimental runs, low I.V. 0.63) and high I.V. 0.92) conventional polyester PET) as spun yarn is compared with as spun yarn set forth in U.S. Patent No. 4,134,882.

4 4 Examples 1-8 are low I.V. polyester (PET) and are made in the manner set forth in Example I. Examples 9-11 are high I.V. polyester (PET) and are made in the manner set forth in Example V. Examples 12-17 correspond to Examples 1, 5, 12, 17, 36 and 20 of U.S. Patent No.

3 4,134,882.

For each examiple, the spinning speed (fpm), density (gins/cc), crystal size 010), long period spacing (LPS), birefringence (bir-P crystal birefringence and amorphous birefringence are given.

0b 4 9 9.4 0 9. 0 *9 4 0099 a', 0 00.

The results are set forth in Table VII.

TABLE VII 030*0 0 0004 0 40 0 000 0094 9 0 00 0 9 13 1 3 0* 4 5 6 .20 8 12 13 0* 14 15 16 17 Spin Speed (cfRpM) 12500 13500 14500 15500 16500 17500 18500 19000 10000 10000 12500 16500 18000 19500 21000 21000 16500 Density gins/ce 1. 37 28 1. 3742 1. 3766 1. 3788 1. 3804 1. 3827 1. 3840 1. 3841 1. 3485 1.3653 1. 3749 1..3700 1 3770 1. 3887 1. 3868 1. 3835 1. 37 66 Cs 0Op

A

45 45 47 50 51 53 55 54 21 43 52 61 73 72 68 64 65

LPS

147 160 155 158 145 152 147 150 192 192 183 313 329 325 330 Biref.

0.1080 0. 1060 0. Li4Q1 0.1120 0.1180 0. 1240 0.1270 0. 13,00 0. 0761 0. 1047 0 .1215 0.0958 0. 1082 0. 1153 0-.1241 0. 1236 0. 0965 Crystal Biref.

0.,1982 0. 1994 0.,2004 0. 2021 0.2035 0.2042 0. 2055 0. 2052 0. 1824 0. 1930 0. 1994 0. 2010 0. 2010 0. 2030 0.,2050 0.1980 0. 2060 Amorphous Biref.

0.067 0.061 0.070 0.060 0,066 0. 071 0.073 0.078 0.063 0.075 0.083 0.045 0. )57 0.054 0.063 0.073 0.038 The present invention may be embodied in other specific forms without departing from the spirit or essential attri!:-tes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims (2)

1. 31- The claims defining the invention are as follows:- 1. A process for spinning a polyester polymer, to produce a filament, the filaments produced by such process being characterized by either: a crystal size of less than about 55 Angstroms and either an optical birefringence greater than about 0.090 or an amorphous birefringence greater than about 0.060 or a long period spacing of less than about 300 Angstroms; or a crystal content of about 10 to about 43%, a spun tenacity of about 1.7 to about 5.0 grams per denier, a spun modulus in the range of about 10 to about 140 grams per denier per 100%, a hot air shrinkage of about 5 to about 45%, and an elongation of about 50-160%, said 10 process comprising the steps of: extruding the polymer through a spinneret; passing the filaments from the spinneret through an elongated zone; maintaining the filaments at a temperature above the glass transition temperature of the polymer over a distance of about 3 meters or greater within the zone; p converging said filaments, and taking up the filament at a spaee- f greater than 3,000 meters perseed-. 2. The process according to claim 1 further comprising the step of: spinning the filaments from the spinneret so that the filaments have a spun denier per filament of 3-20. 3. The process according to claim 1 further comprising the step of: quenching the filaments with a hot gas as the filaments leave the spinneret. 4. The process according to claim 3 further comprising the step of: quenching the filaments with a hot gas having temperature no greater than 260 0 C. The process according to claim 4 further comprising the step of: quenching the filaments with a hot gas having a temperature of 230°C. 6. The process according to claim 1 further comprising the step of: passing the filaments from the spinneret through the elongated zone, said zone having a length of at least 5 meters wherein temperatures in the zone are controlled a 1 A i: i SM-16252-91.CL 6 An11993
2. 32- over the length of the zone from a maximum of the polymer spinning temperature to a minimum of ambient temperature. 7. The process according to claim 6 further comprising the steps of: passing the filaments from the spinneret through the elongated zone wherein temperatures in the zone are controlled from about 155°C proximal the spinneret to about 50°C distal the spinneret. 8. The process according to claim 7 further comprising the step of: passing the filaments from the spinneret through the elongated zone wherein temperatures in the zone are controlled from about 155°C proximal the spinneret to 10 about 50°C distal the spinneret and the temperature between said proximal and distal points decreases in a generally linear fashion. 0* 9. The process according to claim 1 further comprising the step of: passing the filaments from the spinneret through the elongated zone having a length ranging from about 5 to about 9 meters. 10. The process according to claim 1 further comprising the step of: winding up the filaments at a rate of about 5,000 to about 19,000 feet per minute. 11. The process according to claim 1 further comprising the step of: winding up the filament at a rate of about 10,500 to about 13,500 feet per minute. 12. The process according to claim 1 further comprising the step of: winding up the filament at a rate of greater than 14,000 feet per minute after passing the filaments from the spinneret through said elongated zone having been divided into four portions wherein the temperature in the first portion adjacent the spinneret has a temperature ranging from about 105°C to about 110°C; the temperature in the second poition adjacent the first zone has a temperature ranging from about 110°C to about 115°C; the temperature in the third portion adjacent the second zone has a temperature ranging from about 125°C to about 130°C; and the temperature in the fourth portion adjacent the third zone has a temperature ranging from about 115°C to about 120°C. SM-76252-91.CL 6 Alnil 1993 33 13. A process for spinning a polyester polymer, to produce a filament, the filaments produced by such process being characterized by either: a crystal size of less than about 55 Angstroms and either an optical birefringence greater than about 0.090 or an amorphous birefringence greater than about 0.060 or a long period spacing of less than about 300 Angstroms; or a crystal content of about 10 to about gI a spun tenacity of about 1.7 to about 5.0 grams per denier, a spun modulus in the range of about 10 to about 140 grams per denier per 100%, a hot air to shrinkage of about 5 to about 45%, and an elongation of about 501160%, said process comprising the steps of: S* 10 extruding the polymer through a filament forming means; providing an elongated zone having a length of at least 5 meters; passing the filaments from said filament forming means through said elongated zone; s converging the filaments, and taking up the filaments at a speed greater than 3,000 meters per minute. 14. A process for spinning a polyester polymer, to produce a filament, the filaments produced by such process being characterized by either: a crystal size of less than about 55 Angstroms and either an optical birefringence greater than about -0.090 or an amorphous birefringence greater than about 0.060 or a long period spacing of less than about 300 Angstroms; or a crystal content of about 10 to about 43%, a spun tenacity of about 1.7 to about 5.0 grams per denier, a spun modulus in the range of about 10 to about 140 grams per denier per 100%, a hot air shrinkage of about 5 to about 45%, and an elongation of about 5 0 k1 6 0 said process comprising the steps of: extruding the polymer through a filament forming means; providing an elongated zone having means for controlling the temperature within said zone in a generally linear fashion from a predetermined maximum to a predetermined minimum; passing the filaments from said filament forming means through said elongated zone; SM-76252-91.CL 6 ApI 1993 0 34 converging the filaments; and taking up the filaments at a speed greater than 3,000 meters per minute. DATED this 6th day of April, 1993. HOECHST CELANESE CORPORATION CARTER SMITH BEADLE 2 Railway Parade Camberwell 3124 Victoria Australia SM722-eC 60pil19