KR102204383B1 - A Technical polyester fiber with higher tenacity and lower shirinkage and its manufacturing process - Google Patents

Abstract

The present invention is to provide an industrial polyester fiber having high strength and low shrinkage characteristics having a minimum stress of about 130° C. to about 150° C. within about 180° C. to about 200° C., and a method for producing the same.

Description

A technical polyester fiber with higher tenacity and lower shirinkage and its manufacturing process}

The present invention relates to an industrial polyester fiber having high strength and low shrinkage properties, and a method for producing the same. In more detail, the present invention is an industrial polyester having high strength and low shrinkage characteristics having a minimum stress at about 130°C to about 150°C when measuring thermal stress is lower than the minimum stress at about 180°C to about 200°C. It relates to a fiber and a method of manufacturing the same.

Since polyester fibers have various excellent properties, they are widely used not only for clothing but also for industrial use.

In particular, polyester fibers having high strength and excellent dimensional stability are expanding their use not only for tires but also for industrial materials.

Conventional low-shrink polyester fibers are manufactured by heat-treating the drawn yarn at 190°C to 240°C and shrinking to less than 10% as disclosed in Japanese Patent Application No. 58-4089, and the birefringence of the undrawn yarn is too high. The strength was not enough.

In addition, Japanese Unexamined Patent Application Publication No. 46-6459 proposes a method of mitigating the polyester fiber obtained by the direct spinning method after being brought into contact with a drawing roll having a surface temperature of 230°C to 280°C for a short time immediately after drawing. Even in the most advantageous case by the method, only a low shrinkage of about 2% at 160°C (3% at 130°C) could be obtained.

In addition, in this method, in order to further increase the low shrinkage, it is conceivable to increase the heat treatment temperature by the roller to 280°C or higher and to increase the relaxation rate, but in the former case, the fiber's elongation is further lowered, but the stretchability is deteriorated. In the case of, since the fibers are wound around the drawing roller or generate tar, the elongation and low shrinkage properties could not be preferably improved in any case.

In addition, Japanese Patent Laid-Open No. 53-58028 proposes a method of using a low-polymerization polyester in order to lower the shrinkage rate.

However, with this method, although high strength can be obtained by high magnification stretching, it is difficult to obtain fibers having high toughness (toughness) and low shrinkage.

In addition, Korean Patent No. 27734 proposes a polyester fiber heat-treated by passing the polyester fiber cooled, coated with an emulsion, and stretched by a direct spinning method using a highly oriented undrawn yarn through a heating roller at 160°C to 240°C. However, the fiber is excellent in strength and fatigue resistance, but the toughness is not good, and the dry heat shrinkage rate at 175°C is large, from 4% to 7%, so it is insufficient in terms of low shrinkage.

However, the technology for controlling the shrinkage rate of industrial polyester yarns known to date is the most effective technology for controlling the relaxation rate after the drawing roller. Industrial spinning equipment undergoes stretching and heat treatment processes using 5 to 6 stages of Godet Roller (hereinafter referred to as GR) equipment in order to express the functionality of high strength and low shrinkage.

In particular, in order to produce low-shrink yarn, the shrinkage rate is adjusted by the relaxation ratio at GR 5 after going through the stretching process up to GR 4, and the shrinkage stress changes at this time.

Accordingly, an object of the present invention is to provide an industrial polyester fiber having a higher level of strength and a lower level of thermal stress than conventional high strength, low shrinkage industrial polyester fiber.

It is an object of the present invention to determine the viscosity of a polymer suitable for exhibiting physical properties and good fairness, and at the same time, by optimizing spinning and winding conditions, it has a higher level of strength than conventional industrial polyester fibers and a lower level of thermal stress. It is to provide a method of manufacturing a polyester fiber.

The present invention is a polyester manufactured by performing the steps of multi-stage stretching-heat setting-relaxation-stretching-winding a polyester undrawn yarn manufactured by melt spinning polyester chips having an intrinsic viscosity of about 0.95 dl/g to about 1.00 dl/g As a fiber, the minimum stress at about 130° C. to about 150° C. is about 180° C. to 200° C. when measuring thermal stress among yarns that satisfy strength of about 8.0 g/d to about 9.5 g/d and shrinkage of about 0.1% to about 3.0%. It is to provide an industrial polyester fiber having high strength and low shrinkage properties lower than the lowest stress in

In addition, the present invention is prepared through the step of multi-stage stretching-heat setting-relaxation-stretching-winding the undrawn polyester yarn produced by melt spinning polyester chips having an intrinsic viscosity of about 0.95 dl/g to about 1.00 dl/g. As a polyester fiber, it satisfies the conditions of a spinning speed of about 2,000 m/min to about 4,000 m/min, a draw ratio of about 4.0 to about 7.0, and a heat setting GR temperature of about 220° C. to about 250° C., and about It is to provide a method for producing an industrial polyester fiber having high strength and low shrinkage, characterized in that the thermal stress is adjusted by cooling to 0°C to about 20°C.

The industrial polyester fiber having high strength and low shrinkage characteristics according to the present invention described here is the same as the industrial fiber such as tarpaulin or truck cover paper while exhibiting higher resistance to external loads than conventional high strength, low shrinkage yarn. Since it can exhibit a level of dimensional stability, it is possible to increase the added value of the product using it and to impart a low defect rate when manufacturing the product.

1 is a graph comparing the thermal stress of the present invention and the conventional polyester fiber.

The present invention will be described in detail below.

The polyester constituting the polyester fiber of the present invention is a thermoplastic polycondensation of dicarboxylic acid components such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and diol components such as ethylene glycol, propylene glycol and 1,4-butanediol. Esters, specifically polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and copolymerized polyesters obtained by combining these components. In particular, 85 mol% or more of the repeating unit is made of ethylene terephthalate. It is a homopolymer or a copolymer.

When explaining the general manufacturing method of the polyester fiber of the present invention is as follows. In the present invention, the polyester melt produced by melting a polymer having an intrinsic viscosity of about 0.93 dl/g to about 1.05 dl/g and conveying it to the spinneret is in the state of cooled polyester undrawn yarn before the first godet roller.

The undrawn polyester yarn is stretched on a multi-stage roller, then heat-setting on the rollers, relaxation on a roller rotating at high speed, and a stretching process before final winding.

Here, melt-spinning at an appropriate spinning temperature in consideration of the characteristics of the solid-state polymerized polyester chips with each intrinsic viscosity of about 0.93 dl/g to about 1.05 dl/g, and changing the draw ratio and relaxation rate to make the existing industrial polyester It is possible to manufacture an excellent industrial polyester yarn that exhibits a higher level of high strength properties while maintaining the low shrinkage properties of the yarn.

According to one embodiment of the present invention described herein, the spinning speed is about 2,000 m/min to about 4,000 m/min, the draw ratio is about 4.0 to about 7.0, and the heat setting GR temperature is about 220° C. to about 250° C. And cooling to about 0 ℃ to about 20 ℃ (the lower the temperature within this temperature range, the less the shape change in the winding tension, so the thermal stress decreases from about 130 ℃ to about 150 ℃) to adjust the thermal stress. Thereby, it is possible to manufacture the industrial polyester fiber according to the present invention.

In the present invention, the intrinsic viscosity of the polyethylene terephthalate chip is preferably about 0.93 dl/g to about 1.05 dl/g, but when the intrinsic viscosity is less than 0.93 dl/g, it is difficult to develop strength and lower heat resistance, and the intrinsic viscosity is 1.05 dl If it exceeds /g, there is a problem in that it is difficult to control orientation crystallization due to high radiation tension on the radiation line.

In addition, the cylinder temperature of the extruder is preferably about 300 °C to about 315 °C, and when the cylinder temperature is less than 300 °C, the melt temperature is low compared to the viscosity of the polymer, which may lead to a melt inhomogeneity problem due to the occurrence of unmelted material. As the birefringence of the undrawn yarn increases due to an increase in tension, there is a problem in that the stretchability is deteriorated, and when the cylinder temperature exceeds 315°C, the thermal decomposition of the polyester melt is accelerated, making it difficult to express physical properties at the target level. Thereafter, the radiation beam, the hood, the gear pump temperature and cooling conditions can be implemented according to conventional conditions.

The polyester fiber according to the present invention can be manufactured by passing the undrawn yarn prepared under the above conditions through a multistage godet roller and passing through a stretching-heat fixing-relaxation-stretching-winding process.

In the present invention, the draw ratio is preferably from about 4.0 to about 7.0.If the draw ratio is less than 4.0, it is difficult to develop strength due to low fiber orientation, and if it exceeds 7.0, it becomes overstretched, resulting in excessive shrinkage and a single thread. If the yarn appearance becomes poor and this situation persists, complete trimming occurs.

In addition, it is desirable to set the heat setting GR temperature to about 220 ℃ to about 250 ℃. However, if the temperature is less than 220 ℃, the amount of heat transferred to the yarn is insufficient and it is difficult to achieve the shrinkage due to low relaxation efficiency. In this case, the workability decreases as the yarn strength decreases due to thermal decomposition and the generation of tar on rollers increases.

The polyester fiber according to the present invention prepared in this way is from about 130° C. to about 150 when measuring thermal stress among yarns satisfying a strength of about 8.0 g/d to about 9.5 g/d and a shrinkage of about 0.1% to about 3.0%. The minimum stress at °C has properties lower than the minimum stress at about 180 °C to about 200 °C.

The present invention will be described in more detail based on the following examples, and the following examples are for illustrative purposes only and are not intended to limit the present invention thereto.

Example 1

Using a polyester solid polymer chip with an intrinsic viscosity of 0.93 dl/g, the cylinder temperature of the extruder is set to 295°C, and the gear pump temperature, radiation beam temperature, hood temperature, and cooling conditions are conventionally used to prepare undrawn polyester yarn. , At a winding speed of 3500 m/min, a draw ratio of 5.9, a relaxation rate of 12.5%, and a relaxation zone temperature of 248 ℃ were used to prepare a fineness of 1,000 denier-grade yarn of the final drawn yarn.

The strength, cutting (%), shrinkage (%), yarn viscosity, and temperature (°C) during winding of the prepared polyester fiber were measured and shown in Table 1 below.

Examples 2 to 4

Using polyester chips having different intrinsic viscosity, the cylinder temperature of the extruder, the draw ratio and relaxation rate, and the relaxation zone temperature were changed as shown in Table 1 to prepare a fineness of 1,000 denier-grade yarn of the final drawn yarn.

The strength, cutting (%), shrinkage (%), yarn viscosity, and temperature (°C) during winding of the prepared polyester fiber were measured and shown in Table 1 below.

The polyester fiber according to the present invention described herein has a higher level of strength and a lower level of thermal stress than the conventional high-strength, low-shrink industrial polyester fiber [see FIG. 1].

In addition, the polyester fiber according to the present invention determines the viscosity of the polymer material suitable for exhibiting physical properties and good fairness, and at the same time, it has a higher level of strength than the existing industrial polyester fiber by optimizing the spinning and winding conditions. It has a thermal stress of

Claims (2)

As a polyester fiber produced by melt spinning a polyester chip having an intrinsic viscosity of 0.93 dl/g to 1.05 dl/g through the steps of multistage drawing-heat setting-relaxation-stretching-winding, The strength is 8.0 g/d to 9.5 g/d, the shrinkage rate is 0.1% to 1.8%, and the shape does not change under the winding tension as it is wound under cooling at 0°C to 20°C, and the lowest at 130°C to 150°C when measuring thermal stress Industrial polyester fiber having a high strength and low shrinkage property of which the stress is lower than the minimum stress at 180°C to 200°C. As a method for producing polyester fiber through the step of multistage drawing-heat setting-relaxation-stretching-winding of undrawn polyester yarn produced by melt spinning polyester chips having an intrinsic viscosity of 0.93 dl/g to 1.05 dl/g, spinning Satisfies the conditions of speed: 2,000 m/min to 4,000 m/min, draw ratio of 4.0 to 7.0, shrinkage of 0.1% to 1.8%, heat setting GR temperature of 220°C to 250°C, and 0°C to 20°C when winding A method for producing an industrial polyester fiber having high strength and low shrinkage, characterized in that the heat stress is adjusted by winding it under cooling with a furnace so that the shape does not change under the winding tension.

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