JPH06511293A - High modulus polyester yarn for tire cord and composites - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] High modulus polyester yarn industrial applications for tire cord and composites field The present invention provides an extremely high modulus, high tensile strength material particularly useful for tire fabric reinforcement. High tensile strength (tenacity) and low shrinkage rate phthalate (PEN) multifilament yarns and similar rigid Concerning other yarns made from a combination of PEN yarn of the present invention (usually improved modulus and dimensional stability compared to conventionally processed PEN yarns .

One aspect of the present invention relates to a method for making multifilament PEN yarn.

Description of related technology Currently, polyethylene terephthalate (PET) filaments are typically Tire body rubber, conveyor belt, seat belt, ■Used in industrial applications including belts and hoses. However, monoply For high-demand applications such as the body rubber of high-performance tires, a thicker L) modulus or radial passenger car tire belts are desirable. greater modulus and dimensional stability are required. Dimensional stability is 4.5g/d It is defined as the sum of the force and the contraction at . Shima et al. U.S. Patent No. No. 3.616.832 describes a PEN-reinforced bow with good dimensional stability. Rubber products with a tensile strength of Patent No. 3929.180 describes the use of PEN as a carcass reinforcing material. However, these patents are based on the low birefringence when unstretched. LX, relates to PEN processed in a conventional manner and therefore does not fall within the scope of the present invention. However, the potential properties of this material have not been fully realized. . This (well, teaches the optimized drawing of PEN spun by conventional methods) The same applies to British Patent No. 1.445.464 of Hamana etc. be. U.S. Pat. No. 4,000,239 to No\Mana et al. A method for producing LN undrawn PEN with a high melting point and high heat resistance has been proposed. these The material is grown under high stress conditions that favor a highly crystalline or at least highly nucleated structure. These fibers lack stretchability and are not suitable for the intended use of this invention. For products with high modulus (hard to obtain), products for the same application have a large U.S. Patent No. 4.001 to Hamachi et al. for partially oriented yarns with low tensile strength. No. 479.

Summary of the invention The yarns of the invention are partially bonded yarns made in combination with PEN or monomers of similar stiffness. Spinning crystalline polyester polymers to achieve optimal amorphous orientation and crystallinity acoustics Manufactured by The present invention provides processing parameters in at least 0.03 areas. The process is selected to produce an undrawn polyester yarn with a birefringence of 0. Ru. The spun yarn was then hot drawn at a total draw ratio of 1.5/1 to 6.0/1. and the Tg is higher than 100°C and the melting point is at least 8°C higher. A partially crystalline drawn polyester yarn is produced. Desired yarn is tensile strength of at least 6.5 g/d, dimensional stability (EASL + shrinkage) of less than 5%, and The shrinkage rate is 4% or less.

The resulting yarn has a surprisingly high modulus and pull compared to prior art yarns. Shows tensile strength and small shrinkage rate.

Brief description of the drawing Figure 1 shows the modularity of the PEN yarns of Examples 1 and 2 at a tensile strength of 6.2 g/d. This is a comparison of the

DESCRIPTION OF THE PREFERRED EMBODIMENT The polyester multifilament yarn of the present invention can be used as a tire-like rubber material. When added as a fiber reinforcement to composite materials, high modulus, which is a highly desired property, can be added to composite materials. Gives good dimensional stability and high tensile strength. PEN multifilament yarn or a polyester polymer yarn made in combination with monomers of similar stiffness. , reinforcing two parts of a radial passenger car tire, namely the carcass and the belt. It is advantageously used for Currently, the carcass of passenger car tires is mainly made of polyester. Fortified with tylene terephthalate.

Controlled by the dimensional stability of the carcass cord (modulus at a given shrinkage rate) The two tire characteristics are the hardness of the sidewall and the hardness of the sidewall. S) and tire drivability (handling). PEN yarn of the invention Or, the modulus and dimensional stability of polyester yarns are different from those of PET yarns. The fact that the yarns of the present invention are reinforced compared to conventional PEN yarns The indentation hardness of the sidewall of a tire with a flat carcass becomes smaller, This means better driving behavior. The yarn of the present invention is also characterized by its glass The transition temperature (Tg) is higher than 100°C, that is, compared to PET's 7g80°C. PEN is a desirable reinforcement because it has a temperature of 120°C. This high Tg is P Compared to ET tires, the cord generates less heat over a wider temperature range. , resulting in longer tire life and lower overall tire temperatures during driving. (In addition to this, the modulus tends to decrease steeply at temperatures above Tg. The yarn of the present invention maintains its modulus over a temperature range superior to that of PET. . The yarn of the present invention is useful in this application when it is utilized for reinforcing high performance tires. In particular, the cord generates less heat at high temperatures characteristic of high-speed performance operation, and the module All of the above-mentioned advantages are of critical importance as high Ru.

The PEN multifilament yarn of the present invention and other polyester yarns are In addition, belts for radial passenger car tires and carcasses for radial trunk tires It can be used to strengthen the system. PET is suitable for this application at a given cord diameter. Currently, steel wire is used because its strength and modulus are not sufficient. PEN is P The modulus is larger than that of ET, and the PEN of the present invention has an even larger modulus. This makes PEN an ideal material to be used as a replacement for steel wire. It will be.

The polyethylene naphthalate yarn of the present invention contains at least 90 mole percent polyethylene naphthalate yarn. Contains ethylene naphthalate. In a preferred embodiment, this polyester consists essentially entirely of polyethylene naphthalate. In another aspect, this port Re-ester is a combination of ethylene glycol and 2,6-naphthalene dicarboxylic acid or its like. A small amount derived from one or more ester-forming components other than these derivatives. Amount units may be included as copolymer units. polyethylene naphthalene Representative examples of other ester-forming components that can be copolymerized with the ate units include: 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol Glycols such as alcohol, terephthalic acid, isophthalic acid, hexahydride loterphthalic acid, stilpenzcarboxylic acid, bibenzoic acid, adipic acid, sebacin Contains dicarboxylic acids such as azelaic acid and azelaic acid.

The polyester yarn of the present invention is melt spinnable, partially crystalline and 1° Rigid monomers and flexible monomers suitable for producing polymers with Tg higher than °C Polyester polymers made from suitable combinations with I can do it. Examples of rigid monomers include 2,6-naphthalene dicarboxylic acid, 2.7-naphthalene dicarboxylic acid, nophenyl dicarboxylic acid, stilbendical Nocarboxylic acids such as bonic and terephthalic acids: hydroquinone, biphenol , p-kerosene glycol, 1,4-cyclohexanedimethanol, neopentylene Hydroxy compounds such as lengelicol, and p-hydroxybenzoic acid and and hydroxycarboxylic acids such as 7-hydrokyl β-naphthoic acid.

Examples of flexible monomers include /euric acid, succinic acid, adipic acid, and sebacic acid. dicarboxylic acids, and ethylene glycol, 1,3-propanediol, 1. Dihydroxy compounds such as 4-butanediol and 1,6-hexanediol be.

It is important that the price is high.

The multifilament yarns of the present invention generally have a denier per filament. is about 1 to 20 (e.g. about 3 to 10), with a universal range of 6 to 600 continuous fi filaments (eg, about 20 to 400 continuous filaments). Phila The denier per yarn and the number of continuous filaments present in the yarn are As will be obvious to those skilled in the art, a wide range of variations are possible.

This multifilament yarn is manufactured using conventional technology using high-strength polyester fibers. It is particularly suitable for use in industrial applications where it has been traditionally used. This fiber is exposed to high temperatures (e.g. It is particularly suitable for applications in environments where temperatures (100°C) are encountered. This fi Lamentary materials offer high modulus for high modulus fibrous thermoplastics. Not only that, but the shrinkage rate is very small.

The advantage of this greater than expected dimensional stability is at least o,03, preferably 0°0. Highly oriented, characterized by an unstretched birefringence of 3 to 0.30. The characteristic morphological structure generated during spinning is caused by the crystallization of the amorphous region. This is thought to be due to this. This crystallization depends on the level of stress applied during spinning. , which occurs either at the drawing stage or at the spinning stage. If it is too large when spinning When stressed, the undrawn yarn loses its drawability, and in the case of PEN, the characteristic , 2906C.

The characterization parameters given in this specification consist of substantially parallel filaments. Successfully tested multifilament yarns.

1 Birefringence The birefringence is measured using a polarizing microscope equipped with a Berek compensator. It was measured using If the black primary absorption band is not visible, add the purple band. It is best to measure using

2゜! !゛Density was measured at 23°C using an n-heptane/carbon tetrachloride density gradient tube. I met. This gradient tube was prepared and calibrated according to ASTM D1505-68. .

3. Melting point What is the melting point of Perkin-L? -(Perkin-Elmer) differential scanning Absorption obtained by scanning a 10 mg sample at 20°C/min using a calorimeter (DSC). The fever peaked. Tg is the heat capacity related to the glass transition temperature under the same measurement conditions. It is seen as a changing point of inflection. The melting point (△Tm) of the drawn yarn is defined by the following formula: , evaluated: △Tm=Tm’-Tm” where Tm' is the melting point of the drawn yarn in question and Tm'' is the melting point of the drawn yarn in question, and Tm'' is the It is the melting point of a yarn that has been premelted in the equipment and cooled rapidly.

4. Intrinsic viscosity 1 The intrinsic viscosity (IV) of polymers and yarns is a function of the degree of polymerization and molecular weight. It is a convenient measure. IV is a mixed solvent of phenol and tetrachloroethane (60/4 0) Measure the relative viscosity (η2) of the solution. η, is the PEN passing through a standard capillary tube / is the ratio of the flow time of a solvent solution to the flow time of a pure solvent. Iv is relative solution viscosity It is calculated by extrapolating to the concentration 0.

5. Physical properties The tensile properties shown in this specification are Instron tensile properties. Measured using a deformation tester with a gauge length of 10 inches and a deformation rate of 120%/min. Ta. All tensile tests were performed at room temperature. Dimensional stability is achieved at a given shrinkage rate. It is regarded as the level of stress produced. In the tire manufacturing industry, dimensional stability is defined as is defined as the sum of the elongation and contraction of . In the case of the present invention, elongation at a specific load (E ASL) is calculated from the initial modulus data using the following formula: EASL=45 4/Modulus (g/d) Tensile strength and modulus increase with increasing draw ratio. It is well known. Tensile strength by itself is almost always highly desirable. However, due to problems with yarn properties or too much shrinkage, large elongation ratios cannot be achieved. I often can't. The material of the invention has a high level of modulus at a given tensile strength Ru. This is done by calculating the ratio of tensile strength and L-5 using the following formula as the LT parameter. quantified by: L, = ((L-5)'/751g)1000L-5 or LASE-5 is the modulus defined as the load in g/d at 5% elongation. It is a measure of curvature. The material of the present invention has a small number of L (25 in total).

If the yarn elongation is less than 5% and L-5 cannot be measured, before testing, The yarn is pre-relaxed at elevated temperature to increase elongation to more than 5%.

The shrinkage value is determined by applying a binding force of 0.05 g/denier using the ASTM D885 method. Measurements were taken after treatment at 77°C for 1 minute.

It has been found that improved yarns of the present invention can be made, as confirmed below. Explain how. The yarn products claimed below are used in the manufacture of It is not limited by process parameters.

This melt-spun polyester is characterized by the fact that at temperatures above its melting point, the polymer becomes substantially It is fed to the extrusion spinneret at a temperature below the decomposition temperature. Residence time at this stage is kept to a minimum, the temperature not exceeding 350'C, preferably 320'C. should be.

The extruded filament is then passed through a conventional yarn consolidation zone and its spun yarn blowing cooling air into the chamber, thereby freezing the desired internal structural features; It also prevents the filaments from fusing together. The solidification zone includes (a) at least 150'C1 A gaseous atmosphere heated to a temperature of preferably 150 to 500'C. (b) a restrained cooling zone adjacent to the restrained cooling zone, in which the yarn is blown; a cooling zone that is rapidly cooled and solidified in an atmosphere of This is desirable. The key to this process is to adjust the processing conditions to achieve the birefringence. 003 with a melting point improved by 1 to 25°C, preferably 3 to 23°C. The objective is to obtain an undrawn yarn. In PEN, 265 to 29 A melting point of 0° C., preferably 268-288° C., must be achieved. This technique A person skilled in the art would be able to achieve this by adjusting the following conditions: U: Length and temperature of the restrained cooling zone adjacent to the spinneret, pore size of the spinneret, quenching air The method of blowing the body, the velocity of the cooling air and the drawdown rate in the consolidation zone n). The take-off speed of the yarn from the consolidation zone is an important factor affecting the stress in the spun fibers. parameter and must be adjusted to obtain the desired properties. Next Then, the spun yarn is drawn in a conventional continuous or discontinuous manner, thereby increasing the T g is higher than 100°C and the melting point is at least 8°C higher, preferably 8 to 15°C higher. A drawn yarn is obtained. This drawn yarn preferably has the following properties: : 25% tensile strength of at least 6°5 g/d, preferably at least 7.5 g/d Dimensional stability (EASL - Shrinkage) of less than: and shrinkage of 4% or less.

Example 1 (comparative example) through a spinneret with an orifice 0.042 inches long and 0.021 inches wide; 32 filaments were extruded at a discharge rate of 33.2 cc/min to form a PEN undrawn yarn. manufactured. This filament is solidified in an air quenching section, and the winder speed is 30. Pick up ivy at 5m/m1n (min).

The yarn was drawn in two stages using conventional heated rollers. Characteristics of undrawn yarn The quality, properties of the drawn yarn, and drawing conditions are summarized in Table 1.

The yarn of this example was prepared by conventional methods from undrawn yarn of Δn=004. However, it is smaller than the yarn of the present invention, as shown by L, which is smaller than 25. has a high modulus. Also, its dimensional stability parameters (EASL + shrinkage) 8.3, which is greater than the yarn of the present invention, which indicates poorer dimensional stability. show. (See Example 3).

Table 1 Δn　0.004 Tensile strength (g/d) 0. 6 Modulus (g/d) 18.6 Tm (℃) 268 B. Stretched yarn Stretching ratio 63 0-rah 1('C) 140 Roller 2 (℃) 157 0-Ra 3 (℃) Room temperature △n　0. 426 Tensile strength g/d) 6. 2 Modulus (g/d) 176 Tm (℃) 272 Shrinkage rate (%) 5.7 EASL ten contraction (%) 8.3 Threaded through a spinneret with an orifice 0.036 inches long and 0.016 inches wide. PEN yarn was produced by extruding 7 filaments at a flow rate of 9.6 cc/min. Built. This filament is solidified in an air quenching section and the speed range of the winder is 770. The vehicle was picked up at a speed of 5000m/min. This yarn is passed through a heating plate in drawing zone 2. Stretching was carried out in two stages. Properties of undrawn yarn, properties of drawn yarn and stretching The conditions are summarized in Table 2.

A closer look at the data of this example shows that the yarn was stretched to a predetermined tensile strength. As the spinning speed increases, the melting point of drawn and undrawn yarn increases. It can be seen that the modulus increases as you go up. This is because the spinning speed increases. This is reflected in the increase in parameters. Book with only birefringence when unstretched It is insufficient to characterize the yarn of the invention. This parameter has a large spinning stress. This does not define the scope of the present invention because it is not sensitive to changes in morphology that occur in To determine this, both melting point and birefringence must be used. Compare the data of this example For comparison with the data of Example 1, the modulus values in Table 2 were changed to a tensile strength of 6°2. It was rewritten as g/d and plotted against the spinning speed (Figure 1). The result of this analysis is clearly show that the yarn of the invention is superior to yarns according to the prior art. ing.

Example 3 Unrolled fibers of Example 2 spun at spinning speeds of 770 m/min and 4000 m/min The drawn yarn was stretched to its limit. 770 m/min sample was produced using a furnace in the drawing zone. The sample was stretched in one stage at 4000 m/min using a heating plate in the second stretching zone. It was then stretched in two stages. The properties of the drawn yarn and the drawing conditions are summarized in Table 3.

This example shows that the yarn of the present invention has an extremely high modulus, a thick L-bow 1 tensile strength, and and low shrinkage, making it desirable for applications in rubber. Stretch ratio 5. 9 2. 0 Roller 1 ('C) 120 95 Furnace temperature ('C) 170 --- Roller 2 (℃) Room temperature Room temperature Heating plate (’C) 240 Roller 3 ('C)--One chamber Warm tensile strength g/d) 10. 3 7. 6 Modulus (g/d) 362 417 Contraction (%) 3.5 <1 EASL 111 (%) 4. 8 <2. 1L-5 (g/d) 8. 3 7. 5 This example has a higher birefringence and modulus at a slower spinning speed than Example 2. It is possible to create undrawn yarns with high curvature and high melting points, thereby This provides an industrially more viable method for yarns that do not have fast spinning capabilities. This shows that. 0.069" long and 0.030" wide orifice Seven filaments were extruded through a spinneret with a flow rate of 9.6 cc/min. A PEN yarn was produced. This filament is solidified in an air quenching section and wound. The material was picked up at a speed range of 410 to 2500 m/min. The nature of these yarns The quality is summarized in Table 4.

△n 0.17g 0.154 0.192 0.232 0', 233 0. 226 tensile strength g/d) 2.1 2.0 2.6 3.8 4.0 4.5 Modulus (g/d) 64 58 63 114 143 158 Tm('C) 269 267 268 279 291 292 (p15) Z’9 2nd country (+ filter ’pr■゛ and cr: Submission of translation of 6. (Article 184-8 of the Patent Act) July 21, 1994 Ichiden

Claims (1)

[Claims] 1. next: (a) Through an extrusion orifice with multiple apertures, the Tg is greater than 100°C. crystallizable melt polyester polymers with an intrinsic viscosity of 0.6 or higher (b) extruding the body to form a melt-spun yarn; (b) passing the spun yarn through a consolidation zone; (c) the solidified yarn has a birefringence of at least 0. 030 at a non-stretched take-off speed sufficient to form a partially oriented yarn of and (d) hot drawing and drawing the yarn to a total draw ratio of at least 1.5/1. form yarn Stretched polyester with high modulus and good tensile strength, comprising each process How to make Luyaan. 2. The spun yarn is heated to (a) a gaseous atmosphere heated to a temperature of at least 150°C; (b) a restrained cooling zone adjacent to said restrained cooling zone, into which said yarn is blown; a cooling zone that is rapidly cooled and solidified in an air atmosphere; 2. A method according to claim 1, wherein the solidification is effected by passing through a tube. 3. The unstretched take-up speed is 400 to 4500 m/min, and the unstretched birefringence is 3. The method according to claim 1 or 2, wherein the particle size is 0.030 to 0.30. 4. The molten polyester polymer extruded in step (a) is polyethylene naphthalene. and the partially oriented undrawn yarn was heated by 1 to 25°C in step (c). Claim 1 producing a drawn polyethylene naphthalate yarn having a melting point. The method described in section. 5. The spun yarn is removed from (a) a gaseous atmosphere heated to a temperature of at least 150°C; (b) an inhibited cooling zone adjacent to the inhibited cooling zone, in which the yarn is blown; a cooling zone that is rapidly cooled and solidified in an air atmosphere; 5. The method according to claim 4, wherein the solidification is carried out by passing through a. 6. The unstretched take-up speed is 400 to 4500 m/min, and the unstretched birefringence is 0.030 to 0.30, and the increase in the melting point of the partially oriented yarn is 3 to 2. The method according to claim 4 or 5, wherein the temperature is 3°C. 7. Stretched material having a Tg higher than 100°C and an increase in melting point of at least 8°C. partially crystalline polyester multifilament. 8. Tensile strength of at least 6.5 g/d and dimensional stability (EASL + shrinkage) of 5% as claimed in claim 7, which is smaller and has a shrinkage rate of 4% or less. drawn yarn. 9. 9. A drawn yarn according to claim 8, which is polyethylene naphthalate. 10. a melting point increase of 8 to 15°C, a modulus of at least 280 g/d, and Stretched polyester according to claim 9, having a tensile strength of at least 7.5 g/d. Ethylene naphthalate yarn.