KR100208055B1 - 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

Spinning method for producing synthetic yarn of high strength, high modulus, and low shrinkage

1 is a schematic elevation view of a spinning process.

2 is a schematic elevation view of the stretching process.

* Explanation of symbols for main parts of the drawings

10: spinning device 12: extruder

14: radiation beam 16: radiation pack

17: sparger 18: column

19: conical 20, 23: finishing ring

21: exhaust 22: Godeul

24: tension control winding machine 30: creel

34: supply roll 36: hot plate

38: draw rolls

The present invention relates to a spinning process for producing synthetic yarns of high strength, high modulus, and low shrinkage.

Since the introduction of melt-spun synthetic polymers that form fibers, fiber manufacturers have been looking for ways to increase the strength and stability properties of fibers made from such polymers. The additional strength and stability properties of the fibers are necessary to ensure that their products are open to applications beyond their intended use. Such non-textile uses (also known as industrial uses) include tire cords; tailor; Canvas; Fabrics, webs or mats used in roadbed structures or other geo-fabric applications; Industrial belts; Composite materials; Architectural fabrics; Hose reinforcements; Laminated fabrics; Ropes and the like.

Originally, rayon was used for some of these industrial uses. Nylon then replaced rayon as the material of choice. In 1970, conventional polyesters such as polyethylene terephthalate were introduced as competitors to nylon. By 1985, polyesters with higher performance, ie higher strength and greater stability were introduced.

A brief review of some prior art, summarized below, shows that three general areas have been investigated as possible ways to improve the strength and stability properties of such synthetic fibers. Such general areas include processes relating to drawing; A process relating to a polymer; And spinning. The term stretching then refers to heating and stretching applied to the yarn in the spun state. The term treatment for a polymer refers to those that are done to a spinning polymer. The term spinning is a process for forming a filament from a polymer, but means a process that excludes stretching.

The process for drawing is as follows:

In US Pat. No. 3,090,997, multistage stretching of polyamides for use as tire cords is disclosed. The fibers (nylon) are melt spun in a conventional manner. The spun fibers are then stretched in a three-step process (stretched and then heated and then stretched again) to obtain stretched nylon having the following properties: linear strength in the range of 10.4-11.1 g (gpd) per denier; Elongation in the range of 12.9-17.1%; And an initial modulus of 48-71 gpd / 100%.

In US Pat. No. 3,303,169, a one-step drawing process for polyamides is disclosed which produces polyamide yarns of high modulus, high linear strength, and low shrinkage. Spinned polyamides are stretched and at least 115 Heated to, linear strength in the range of 5-8.7 gpd; Elongation in the range of 16.2-30.3%; Initial modulus of 28-59 gpd / 100%; And a yarn with a shrinkage in the range of 3.5-15%.

In US Pat. No. 3,966,867, a two-step stretching process for polyethylene terephthalate with a relative viscosity of 1.5-17 is disclosed. In the first stage, the fibers are 70 to 100 Applies to the temperature of and the draw ratio of 3.8-4.2. In the second stage, the fibers are 210 to 250 The temperature of and the sum of the first draw ratio and the second draw ratio apply to draw ratios in the range of 5.6-6.1. The drawn yarn has the following properties: linear strength, 7.5-9.5 gpd; Elongation, approximately 2-5 at a load of 5 gpd; Break elongation, 9-15%; And shrinkage, 1-4%.

In US Pat. No. 4,003,974, 72-250 while stretching a polyethylene terephthalate yarn having an HRV of 24-28. Heat to then pass over the heated draw rolls and finally relax. Drawn yarns have the following properties: linear strength, 7.5-9 gpd; Shrinkage, about 4%; Elongation at break, 12-20%; And internal load of 3-5 gpd at elongation of 7%.

Such processes relating to the properties of the yarn improved by the treatment on the polymer are as follows:

In US Pat. Nos. 4,690,866 and 4,867,963, the intrinsic viscosity (IV) of polyethylene terephthalate is at least 0.90. In US Pat. No. 4,690,868, the properties of the spun (undrawn) fibers are as follows: elongation at break, 52-193%; Birefringence, 0.0626-0.136; And crystallinity, 19.3-36.8%. The properties of the drawn fibers are as follows: linear strength, 5.9-8.3 gpd; Elongation; 10.1-24.4%; And dry shrinkage (210 ), 0.5-10.3%. In US Pat. No. 4,867,936, the properties of the drawn fibers are as follows: linear strength, about 8.5. gpd; Elongation at break; About 9.9%; And shrinkage (177 ), About 5.7%.

Such processes for spinning are as follows.

In U. S. Patent No. 3,053, 611, after leaving the spinneret, polyethylene terephthalate is removed in a 2 m long spinning shaft. Heat to Thereafter, cold fibrous water in the second shaft is sprayed. The fibers are taken at a speed of 1,600 meters per minute (mpm) and subsequently drawn to obtain a linear strength of 3.5 gpd.

In U.S. Patent No. 3,291,800, the polyamide is spun from spinneret and then about 15 Cool to and then spray live steam on the fibers. The fibers in the spun state have low orientation and low birefringence.

In US Pat. No. 3,361,859, synthetic organic polymers are spun into fibers. When the fibers exit the spinneret, they are subjected to controlled delayed cooling. This cooling is performed over the first 17.8 cm (7 inches) from the spinneret. At the top (ie adjacent to spinneret) the temperature is 300 And the lowest temperature at the bottom (ie, approximately 17.8 cm (7 inches) from the spinneret) is 132 to be. The yarns in the spinning state have frequent birefringence (11-35 × 10 ⁻³ ) and the properties of the stretched yarn are as follows: linear strength, 6.9-9.4 gpd; Early modulus, 107-140 gpd / 100%; And elongation at break, 7.7-9.9%.

In US Pat. Nos. 3,936,253 and 4,96,462, about 115-460 The use of heated shrouds (lengths in the range of 15 cm (1/2 ft)-60 cm (2 ft)) with temperatures in the range is disclosed. In the above-mentioned 3,963,253 above, the temperature is higher at the top than at the bottom of the cover. Its properties are drawn as follows: linear strength, 9.25 gpd; Elongation, about 13.5%; And shrinkage, about 9.5%, in Patent No. 3,969,462, wherein the temperature is constant in the sheath and the properties of the stretched yarn are as follows: linear strength 8-11 gpd; And elongation at break, 12.5-13.2%.

In U. S. Patent No. 3,946, 100, the fibers are allowed to spin out of the spinneret and Solidify at a temperature below. The solidified fiber is then reheated to a temperature between the glass transition temperature (Tg) of the polymer and its melting temperature. This heated fiber is withdrawn from the heating compartment at a speed of 1,000-6,000 meters per minute. The properties of the yarn are as follows: linear strength 3.7-4.0 gpd; Initial modulus, 70-76 gpd / 100%; And birefringence, 0.1188-0.1240.

In US Pat. No. 4,491,657, polyethylene multifilament yarns are melt spun and solidified at a high rate. Solidification occurs continuously in a compartment comprising a heating compartment and a cooling compartment. The heating compartment is a barrel-shaped heater with a length in the range of 0.2-1.0 m (melting temperature of polymer to 400 Range of temperatures). Cooling compartments are 10 to 40 Is cooled by air at Drawn yarns produced by this process have the following properties: initial modulus, 90-130 gpd; And shrinkage of up to 8.7% (150 in).

In US Pat. No. 4,702,871, fibers are spun into a decompression chamber. The properties of the yarn are as follows: strength, 3.7-4.4 gpd; Birefringence 104.4-125.8 (× 10 ⁻³ ); And 160 Dry heat shrinkage for 15 min at 4.2-5.9%.

In US Pat. No. 4,869,958, the fibers are spun without heat and then taken out. In this respect, the fibers have a low crystallinity but are very oriented. Thereafter, the fibers are heat treated. The properties of the drawn fibers are as follows: linear strength, 4.9-5.2 gpd; Initial modulus, 92.5-96.6 gpd / 100%; And elongation, 28.5-32.5%.

Kendo to the patents indicate that some of the fibers produced by these various processes have high strength or low shrinkage properties, but none of the patents have both high linear strength, high initial modulus, and low shrinkage It is not guiding such a drawer or a method for its preparation.

The closest patents to guide such drawers are the relevant patents assigned to the assignee of the present invention, ie, US Pat. Nos. 4,101,525 and 4,195,052. In this patent, polyethylene filaments (polymers having an inherent viscosity of 0.5-2.0 dl per gram) are melt spun from the spinneret. The molten filaments pass through their solidification sections, which are quenched into their uniform and transformed into solid fibers. Solid fibers are drawn from the solidification section under substantial stress (0.015-0.15 gpd). Solid fibers in this spinning state exhibit relatively high birefringence (about 9 to 70 × 10 ⁻³ ). The fibers in the spun state are then stretched and subsequently heat treated. The properties of the drawn filaments are as follows: linear strength, 7.5-10 gpd; Initial modulus, 110-150 gpd 100%; And shrinkage, 175 Less than 8.5% in air.

Disclosed herein are methods for spinning organic synthetic melt radioactive polymers. The method extrudes the polymer through the spinneret; Passing the filament from the spinneret through a long compartment; The filament is maintained at a temperature above the glass transition temperature of the polymer over a distance of about 3 m or more in the compartment; Then converging the filaments.

Alternatively, the method extrudes the polymer through the spinneret; Providing means for adjusting the temperature in said compartment from a predetermined maximum to a predetermined minimum, ie an elongated compartment having a length of at least 5 m; Passing the filament through the compartment; And then converging the filaments.

For the purpose of illustrating the invention, a schematic of a presently preferred method is shown in the drawings, but it is understood that the invention is not limited to the precise arrangements and instrumentalities shown.

High straight line strength, high initial modulus, and low shrinkage of stretched yarns and but methods of spinning yarns are discussed later. The term yarn (or yarn) or filament or fiber refers to any fiber made from a meltspun synthetic organic polymer. Such polymers may include, but are not limited to, polyesters and polyamides. However, the present invention is particularly concerned with polyesters such as polyethylene terephthalate (PET), PET and blends of polybutylene terephthalate (PBT), and PET crosslinked with polyfunctional monomers (eg pentaerythritol). have. The polymers may all contain conventional additives. I.V. of yarns (for PET based polymers). May be 0.60 to 0.87. However, the present invention does not depend on the intrinsic viscosity (I.V.) of the polymer.

Referring to FIG. 1, a radiator 10 is shown. A conventional extruder 12 for molten polymer chips is in fluid communication with a conventional spinning beam 14. Within the spinning beam 14 there is a conventional spinning pack 16. Pack 16 may be of annular design, which filters the polymer by passing the polymer through a bed of fine particles, as is known in the art. As part of the pack 16, conventional spinnerets (not shown) are included. The flow rate of the polymer through the pack may range from about 4.5-25 kg (about 10-55 lb) per hour. The upper limit of 25 kg (55 lb) is defined only by the physical dimensions of the pack 16, and larger flow rates can be obtained by the use of larger packs. Spun denier (gpf) per filament is in the range of 3-20; The optimum properties and mechanical qualities of the yarns are shown as 5-13 dpf.

Optionally, the fibers may be quenched with hot inert gas (eg air) when leaving the spinneret. See US Pat. No. 4,378,325. Typically, the gas is about 230 And about 6 standard cubic feeds per minute (scfm). If the air is too hot, i.e. 260 If it is above, the property of a yarn will be considerably deteriorated.

The elongated column 18 is fitted just below the spinning beam 14 (i.e., not through the air). The column includes an insulated tube having a length of about 5 m or more. The column lengths will be discussed in more detail below. The inner diameter of the tube is large enough to allow all filaments from the spinneret to pass through the length of the tube without obstruction (eg, 30.5 cm (12 inches)). The column is equipped with a number of conventional band heaters so that the temperature in the tube can be adjusted along its length. Column temperatures will be discussed in more detail below. The column is preferably subdivided into many separate temperature sections for better temperature control. A total of 4-7 compartments are used. Optionally, column 18 may include an air sparger 17 that is used to adjust the temperature in the column. The sparger 17 is designed to distribute the inert gas evenly around the column.

Inside the bottom end of column 18 is a porous truncated cone 19, i.e. a means for reducing air turbulence. Conical section 19, preferably 91.5 cm (3 feet) long and having a diameter at the top of the same width as the tube diameter and a diameter of about 1/2 of the tube diameter at the bottom, is a thread line due to air turbulence. Is used to evacuate air from the bottom of the tube through the valved exhaust port 21 so that movement in the valve is substantially reduced or completely eliminated.

The solid line converges below the bottom of the column. This convergence can be performed by a finish applicator 20. This is the first contact that the thread makes after leaving the spinneret.

The length of the column, the non-convergence of the individual filaments, and the distribution of air temperature in the column are of particular importance in the present invention. With regard to the temperature distribution, this is chosen such that the fiber is maintained at a temperature above the Tg of the fiber over a significant length of the column (eg, at least 3 m). This temperature can be maintained over the entire length of the column, but the wound filament will be unstable. Therefore, for practical reasons, the temperature in the column is reduced to below Tg, so that the filament will not undergo any further changes in the crystal structure before it is wound. Preferably, the temperature distribution is chosen to reflect the temperature distribution set in the tube if no external heat is applied. However, situations without any external heat are impractical due to many variables affecting column temperature. Therefore, the temperature distribution is preferably adjusted in a linear manner to exclude the temperature as a variable in the process.

The air temperature in the column is controlled by the use of a band heater. Preferably, it is divided into a plurality of compartments of the column, and the temperature of the air in each compartment is adjusted to a predetermined value. Therefore, the temperature in the column can vary over the column length. The temperature in the column is as high as the spinning temperature of the polymer to the glass transition temperature (Tg) of the polymer (the Tg of the polyester is about 80 Or below). The spinning temperature of the polymer occurs around the spinneret, ie when the molten polymer exits the spinneret. Such, the air temperature in the column is preferably about 155 From about 50 Can be adjusted. At winding speeds below 4300 m (14,000 ft) per minute, the first compartment adjacent to the spinneret is preferably about 155 Controlled to a temperature of, the compartment furthest from the spinneret is about 50 Is adjusted.

However, the linear temperature distribution is not the only temperature pattern that will yield the beneficial results disclosed herein. At a take-up (or winding) rate above 4300 mpm (14,000 fpm), the temperature distribution (when the column is divided into four separate compartments) can be as follows: First compartment (starting from below the spinneret) 105 To about 110 ; Second compartment- about 110 To about 115 ; 3rd compartment-about 125 To about 130 ; And fourth compartment-115 To about 120 .

For column lengths, a minimum column length of 5 m with convergence of filaments (having a column temperature of at least 3 Tm of polymer for at least 3 m) appears to be necessary in the present invention. Column lengths of 5-9 m are suitable for the present invention. The upper limit of 9 m is a practical limit and can be further increased as the room space allows. In order to optimize the linear strength properties, a column length of about 7 m is preferred.

The fibers converge after exiting column 18. This convergence can be performed by the use of the finishing ring 20.

After the first application of the finish (ie in finish ring 20), the yarn is hung around a pair of godet rolls 22. Thereafter, a second finish application can be done (ie at finish 23). The first finish application can be done to reduce the static charge on the fibers. However, this finish is sometimes peeled off as the fibers pass through the gouda roll. Therefore, the finish can be applied again after passing through the ancient roll.

The fibers then pass over a conventional tension control roll winder 24. Winding speeds are typically above 3,000 mpm (9,800 fpm) and the maximum speed is 5,800 mpm (19,000 fpm). The optimal range is between about 3,200-4,100 mpm (about 10,500-13,500 fpm). The most preferred range is between 3200-3800 mpm (about 10,500-12,500 fpm). At speeds below 3,000 mpm (9,800 fpm), the uniformity properties of the yarns deteriorate.

The spun polyester yarns produced by the process can be characterized as having generally relatively small crystals and relatively high orientation. It is believed that the spinning yarns have the unique stretch properties discussed below.

In order to quantify the general characteristics of the spun polyester yarn, small crystals were used as crystal size ( And orientation is defined by the following terms: optical birefringence; Amorphous birefringence; Or crystalline birefringence. Polyester yarns are also characterized in terms of crystal size and long-term spacing (distance between crystals). In broad terms, spun polyester yarn 55 Less than 0.090 optical birefringence or 0.060 or greater amorphous birefringence or 300 It can be characterized by having the following long-term intervals. More preferably, the spun polyester yarn is about 20 to about 55 Crystal birefringence in the range and from about 0.090 to about 0.140 or amorphous birefringence in the range of about 0.060 to about 0.100 or about 100 to about 250 It can be characterized as having a long interval of range. Most preferably, the spun polyester yarn is 43 to 54 Crystal birefringence in the range and about 0.100 to 0.130 or amorphous birefringence in the range of 0.060 to about 0.085 or about 140 to about 200 It can be characterized as having a long interval of range.

As will be apparent to those skilled in the art, the crystal size of the yarn is about one third of the conventional yarn in the optimum winding speed range. The crystal size increases with speed but still remains low. The amorphous orientation of the yarn is very high, about twice that of normal. This yarn has such high orientation and low shrinkage and can be used without any stretching. In addition, polyester spun yarn has the following properties: crystal content (ie, crystallinity level measured by density) of 10-43%; Spun yarn linear strength of about 1.7-5.0 gpd; Spun yarn modulus in the range of 10-140 gpd / 100%; Hot air shrinkage of about 5-45%; And elongation of 50-160%.

After that, the yarn is stretched. See Figure 2. One-step or two-step stretching operations can be used. However, the second step was judged to provide little or no additional benefit. The spinning operation may be directly connected to the stretching operation. (Ie spinning / drawing process).

The yarn in the spinning condition is from the creel 30 to an ambient temperature of about 150 It can be fed onto a supply roll 34 which can be heated up to. After that, the fibers are at ambient temperature to approximately 255 It is fed onto a draw roll 38 which can be heated at. If you can't find a heated roll, 180 to 245 It is possible to use a hot plate 36 that can be heated with. A hot plate 36 (having a curved contact surface of 15.2 cm (6 inches)) is placed between the draw zone, ie, the feed roll 34 and the draw roll 38. The stretching speed is in the range of 75-300 m per minute. Typical draw ratios are about 1.65 (for yarns made at about 3,800 meters per minute). The optimum supply roll temperature, which provides the highest tensile strength, is about 90 Was found to be. The optimum stretching roll temperature is about 245 to be. When a hot plate is used, the optimum temperature is about 240 To 245 to be. The temperature of the draw rolls gives some control over the thermal air shrinkage. In general, low shrinkage is preferred because it results in the best treated cord stability rating. However, at least one purpose application, canvas, requires higher draw yarn shrinkage, which can be controlled with lower draw roll temperatures.

On the basis of the above, the properties of the stretched yarn can be adjusted as follows: The linear strength can be in the range of 4.90-10.8 g per denier. Elongation may range from 7% to approximately 80%. Initial secant modulus may range from 60-170 gpd / 100%. Hot Air Shrinkage (177 ) Is 6% to 15%. Deniers of fiber bundles can range from 125-1100 (number 1100 can be obtained by plying two together), and denier per filament ranges from 1.5-6 dpf. Such yarns can be used as fiber reinforcements in rubber tires.

Polyester (i.e., PET), ie, stretched yarns prepared according to the method can obtain an initial secant modulus of at least 150 g / 100 per denier. In addition, the yarn may also have a shrinkage of 8% or less, or may have a linear strength of at least 7.5 g per denier.

One preferred embodiment of the polyester drawn yarn may be characterized by the following: a linear strength of at least 8.5 g per denier; An initial modulus of at least 150 g / 100% per denier, and a shrinkage of 6% or less. Another preferred embodiment of the polyester drawn yarn may be characterized by: at least 10 g of linear strength per denier; At least 120 g / 100% initial modulus per denier, and at least 6% shrinkage. Another preferred embodiment of the polyester drawn yarn may be characterized by the following: linear strength in the range of about 9 to about 9.5 g per denier; Initial modulus in the range of about 150-158 g / 100% per denier, and shrinkage of at least 7.5% or less.

Any drawn yarns produced according to the method can be used for the following end uses: tire cords; Sewing thread; Canvas; Fabrics, webs or mats, industrial belts used in roadbed structures or other geo-textile applications; Composite materials; Architectural fabrics; Hose reinforcing agents; Laminated fabrics; Rope etc.

The following important tests, to be used in the following discussion of the present invention and subsequent examples, were performed as follows.

Straight line strength refers to the breaking straight line strength as defined in ASTM D-2256-80.

The initial modulus (or initial secant modulus) is defined by ASTM D-2256-80, section 10.3, except that the line representing the initial straight portion of the stress strain curve has an elongation of 0.5% and 1.0% on the stress strain curve. The exception is that it is defined as a line through the point.

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

Shrinkage (HAS) is 177 ± 1 according to ASTM D-885-85 It is defined as the linear shrinkage rate in a hot air environment maintained at.

Density, crystal size, long-term spacing, birefringence, and amorphous birefringence are as set forth in US Pat. No. 4,134,882. Specifically, each of the foregoing is described in US Patent No. 4,134,882: Density—Column 8, Line 60; Crystal size-column 9, line 6; Long term intervals-column 7, line 62; Crystal birefringence-column 11, line 12; And amorphous birefringence-at or near column 11, line 27.

Birefringence (optical birefringence or Δn) is as shown in US Pat. No. 4,101,525, column 5, lines 4-46. Bi CV is the coefficient of optical birefringence parameter between the filaments calculated from the 10 measured filaments.

The other tests mentioned here are carried out by conventional methods.

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

Example 1

In the following set of experimental runs, a conventional polyester polymer (PET, IV-0.63) was spun. Spinning speed increased from 380 mpm (12,500 fpm) to 5800 mpm (19,000 fpm). The column length was 6.4 m and divided into four temperature control sections. Temperature was adjusted by measuring the air temperature close to the wall at the center of each compartment. Polymers 285 Extruded through the spin beam and 40 holes spinneret (hole size 0.023 cm (0.009 inches) x 0.033 cm (0.013 inches)) at a rate of 10.4 kg (22.9 lb) per hour. The fibers were not quenched. The spun fibers were not stretched but were heat treated. The results are shown in Table 1.

Example 2

In the following set of experimental runs, conventional polyester (PET, IV-0.63) was spun. Column temperature (air temperature, center of compartment) was changed as shown. The column length was 6.4 m. 300 polymers Extruded at a rate of 10.5 kg (23.1 lb) per hour through a spin beam at and an aperture of 72 holes (hole size 0.023 cm (0.009 inch) x 0.030 cm (0.012 inch)). The fibers were not quenched. Spinning fibers were drawn continuously (as shown). The results are shown in Table 2.

In this set of trial runs (ie, those shown in Table 2), numbers 4, 5, 6 and 7 represent the present invention.

Example 3

In the following set of test runs, conventional polyester (PET, IV-0.63) was spun. The fibers were wound up at a speed of 3200 mpm (10,500 fpm). The polymer was spun with 72 holes (hole size 0.023 cm (0.009 inch) × 0.030 cm (0.012 inch)) and 300 Was extruded at a rate of 8.8 kg (19.5 lb) per hour through a spinning beam of. 232 fibers Was quenched with 6.5 scfm of air at. The column was 6.4 m long, with the following air temperature distribution (in descending order) at the center of the compartment: 135 ; 110 ; 92 ; And 83 It was divided into four sections with. Spinning yarns had the following properties: denier-334; Linear strength 4.09 gpd; Elongation at 71.7%; Initial modulus-55.0 gpd / 100%; Hot Air Shrinkage-176.7 (350 ) At 11.8%; Worcester 1.10; IV-0.647; FOY-0.35%; Birefringence-110 x 10 ^-3 ; And crystallinity -21.6%.

Table 3a shows the effect of the draw ratio on the properties of the drawn yarn.

In Table 3b, the effect of the heating method during stretching is shown (the stretching ratio was 1.65 and the yarn was not relaxed).

In Table 3c, the effects of higher draw temperatures and draw ratios are shown (the feed roll is at ambient temperature and the draw roll is 240 Is in).

Example 4

In the following set of test runs, conventional polyester (PET, IV-0.92) was spun. In Run Nos. 1-5, the fibers were spun and stretched according to the methods set forth in US Pat. Nos. 4,101,525 and 4,195,052. Numbers 6-9 were prepared as follows:

PET with a molecular weight characterized by an IV of 0.92 was dried to a moisture level of 0.001% or less. This polymer was melted in an extruder and 295 After heating to the temperature of, it was sent to the spinning pack by a metering pump. This pack is a ring-shaped design that filters the polymer by passing the polymer through a bed of finely divided metal particles. After filtration, the polymer was extruded through 80 holes spinneret. The hole in each spinneret had a capillary length of 0.610 mm and a circular cross section of 0.457 mm diameter.

A 9 m long insulated heated tube was fitted snugly under the pack and the entire length of the tube was passed before contacting or converging the multifilament spinning solid line with any guide surface. The tube was divided into seven sections for the purpose of temperature control. Individual regulators were used to adjust the air temperature at the center of each of these compartments. Using a combination of external heaters and process heat around the tubes, the individual regulator settings were chosen to have a uniform air temperature distribution below the vertical distance of the tubes. In a typical situation, the temperature of air is 155 in the upper compartment of the tube And the temperature was 50 at the bottom Decreasing to approximately uniform slope.

About 10 cm below the tube, the solid line was in contact with the finish ring, which also served as the first contact with the convergence guide and the thread. Due to the proximity of the finish guide to the exit of the tube, the cross section of the unconverged yarn was very small. This allows very small apertures to be used, thereby minimizing the amount of hot air lost from the tube.

Application of the spin finish, the thread was caught in a pair of Gordle rolls and then a tension-controlled winder. Winding speeds are typically in the range of 3200-4100 mpm.

Stretching of this thread was carried out in the second stage, where the spun yarn was subjected to a set of pretensioned rolls to 80-150 It was sent to a heated feed roll maintained at a temperature set to. And then roll these threads and 180-255 A stretch was drawn between a set of draw rolls maintained at a selected set point within the range. A typical draw ratio for a spun yarn made at 3800 mpm would be 1.65, and samples spun at higher or lower speeds require lower or higher draw ratios, respectively.

The results are shown in Table 4.

Example 5

The polyester having a molecular weight characterized by an IV of 0.92 was dried to a moisture level of 0.001%. This polymer was melted in an extruder and 295 After heating to a temperature of, the molten mule was sent to the spin pack by a metering pump. After filtration in a bed of finely divided metal particles, the polymer was extruded through an 80 hole spinneret. The hole in each spinneret had a diameter of 0.457 mm and a capillary length of 0.610 mm. The measured IV of this polymer at extrusion was 0.84.

The extruded polymer was spun into a heated cylindrical cavity of 9 m length. A nearly linear temperature distribution (tilt) was maintained over the entire length of this tube. At the center of the upper compartment the air temperature is 155 The temperature at the bottom of the tube was 50 It was. The multifilament yarn bundles converged after contact with the finish guide just below the outlet of the heated tube. From this point the thread was sent to a tensioner which was tensioned by a pair of Godol Rolls. Under these conditions, a series of four yarns were produced at different spinning (winding) rates. These yarns are referred to as A to D in Table 5a.

In another series of tests, the heated tube was shortened by removing some removable compartments. In Table 5a Examples E and F were spun through a column of 7 and 5 meters. Other polymers with different molecular weights (IV's) were also spun on this system to provide examples G and H. In Table 5a, Example I shows where lower column temperatures are used. In this case, 125 toward the bottom of the column To 50 The slope of the straight line was set.

All yarns in the series A to I were supplied to the surrounding feed The drawing rolls were used to draw in a single step process.

In another series of tests, the same yarns as described in Example A were drawn using different feed roll temperatures. The results of testing these yarns are shown as examples A, J and K in Table 5b.

Example 6

In the following test runs, conventional polymer nylons were spun in accordance with the method of the present invention and compared to nylons prepared by conventional methods.

The nylon made by the process of the present invention was spun under the following conditions: throughput- 16.8 kg (37 lb) per hour; Spinning speed -720 mpm (3362 fpm); Denier -3500; Filament number -68; Spun yarn relative viscosity -3.21 (HSO) or 68.4 (HCOOH equivalent); Quench air -72 scfm; Winding tension 80 g; Column length -7.32 m (24 ft); Column top temperature 240 And bottom 48 . The properties of the spinning condition of this yarn were as follows. Linear strength -0.95 gpd; Elongation 235%; TE ^1/2 -14.6. The yarn was then drawn under the following conditions: draw ratio 3.03; Stretching temperature 90 . The properties of the drawn yarn are as follows: linear strength 6.2 gpd; Elongation -70% TE ^{/ 2} -52; 10% modulus -0.87 gpd; 371 (400 Hot Air Shrinkage Rate (HAS) at -1.4%.

One comparative nylon was spun in the following conventional manner: throughput-10.6 kg (23.4 lb) per hour; Spinning speed -257 mpm (843 fpm); Denier -5556; Filament number -180; Spun yarn relative viscosity -3.3 (H ₂ SO ₄ ) or 72.1 (HCOOH equivalent); Quenching -150 scfm. Thereafter, the yarn was stretched under the following conditions. Draw ratio -2.01; Stretching temperature -90 . The properties of the drawn yarn are as follows: linear strength 3.8 gpd; Elongation -89% TE ^{/ 3} -33; 10% modulus -0.55 gpd.

Another comparative yarn was spun in the following conventional manner: Throughput—26.1 kg (57.5 lb) per hour; Spinning speed -320 mpm (1048 fpm); Denier -12400; Filament number -240; Spun yarn relative viscosity -42 (HCOOH equivalent); Quenching air -150 scfm; After rm, the yarn was stretched under the following conditions. Draw ratio -3.60; Stretching temperature -110 . The properties of the drawn yarn are as follows: linear strength -3.6 gpd; Elongation -70% TE ^{/ 2} -30.1; Modulus -0.8 gpd at 10% elongation; HAS (370 (400 -2.0%).

Example 7

In the following implementation, low I.V. (Such as 0.63) and high I.V. Conventional polyester (PET) spun yarn of (e.g., 0.92) is compared to the spun yarn presented in US Pat. No. 4,134,882. Examples 1-8 show low I.V. Polyester (PET) and is prepared in the manner set forth in Example 1. Examples 9-11 show high I.V. Polyester (PET) and prepared in the manner set forth in Example 5. Examples 12-17 correspond to Examples 1, 5, 12, 17, 36, and 20 of US Pat. No. 4,134,882.

For each example, spin rate (fpm), density (gms / cc), crystal size ( , 0.10), long-term spacing (LPS), birefringence (biref.), Crystal birefringence and amorphous birefringence are shown. The results are shown in Table 6.

The invention may be embodied in other specific forms without departing from its spirit or its essential characteristics, and therefore, in indicating the scope of the invention, reference should be made to the appended claims rather than to the foregoing specification.

Claims (17)

Extruding the polymer through the spinneret; Passing the filament from the spinneret through a long compartment; The filament is maintained at a temperature above the glass transition temperature of the polymer over a distance of 3 m or more in the compartment; Then converging the filaments. The method of claim 1, wherein the polymer is polyester and further comprises winding the filament at a rate of at least 3000 m / min after convergence. The method of claim 1, further comprising spinning the filament from the spinneret such that the filament has spun denier per 3-10 filaments. The method of claim 1, further comprising quenching the filament with hot gas when the filament leaves the spinneret. The method of claim 4, wherein 260 And quenching with hot gas having a temperature below. The filament of the spinneret of claim 1, wherein the temperature in the compartment is passed through a long compartment having a length of at least 5 m, which is adjusted over the entire length of the compartment from the maximum of the polymer spinning temperature to the minimum of the ambient temperature. The method comprises the steps of. The method of claim 6, wherein the temperature in the compartment is 155 near the spinneret. 50 away from spinnerette Passing the filament from the spinneret through a long compartment that is controlled until. The method of claim 7, wherein the temperature in the compartment is 155 near the spinneret. 50 away from spinnerette And passing the filament from the spinneret through a long section that is adjusted to and through a long section in which the temperature between the simmer and the distant is reduced in a linear manner. The method of claim 1, comprising passing the filament from the spinneret through a long compartment having a length in the range of 5 to 9 m. The method of claim 2, further comprising winding the filament at a speed of 3000 m / min to 5795 m / min. The method of claim 2, further comprising winding the filament at a speed of 3200 m / min to 4120 m / min. The method of claim 2, wherein in the first portion near the spinneret 105 To 110 With a temperature in the range 110 in the second compartment next to the first compartment To 115 Has a temperature in the range; 125 in the third compartment next to the second compartment To 130 Has a temperature in the range; 115 in the fourth compartment next to the third compartment To 120 Passing the filament from the spinneret through a long compartment divided into four parts having a temperature in the range, and then winding the filament at a speed of at least 4270 m / min. Extruding the polymer through the filament forming means; Providing a long compartment having a length of at least 5 m; Passing the filament from the filament forming means through the elongated compartment; Then converging the filaments. Extruding the polymer through the filament forming means; Providing an elongated compartment having means for adjusting the temperature in the compartment from a predetermined maximum to a predetermined minimum; Passing the filament from the filament forming means through the elongated compartment; Then converging the filaments. The method of claim 14, wherein the temperature in the long compartment is adjusted in a straight line manner. The method of claim 2, wherein 55 Less than 0.090 optical birefringence or 0.060 or greater amorphous birefringence or 300 The filament is produced by the following long-term spacing. 19. The method according to claim 2 or 18, wherein the crystal content of 10 to 43%, the yarn linear strength of 1.7 to 5.0 g per denier, the yarn modulus in the range of 10-140 g / 100% per denier, and the hot air shrinkage of 5 to 45%. And a filament characterized by an elongation of 50 to 160%.