KR101047046B1 - A manufacturing method of polyester yarn - Google Patents

Abstract

PURPOSE: A method of manufacturing polyester fiber is provided to offer polyester undrawn yarn having stretching uniformity with excellent properties of matter such as high elasticity and high intensity. CONSTITUTION: The method of manufacturing polyester fiber is as follows. In the method of manufacturing polyester fiber, a spinneret melt spins and cools a polyester resin of inherent viscosity of 0.8 - 1.5. The undrawn yarn has a tube having a path which is maintained at a temperature of 50-150°C, passes through the path of the tube, and is heated. The heated undrawn yarn is heat treated and stretched.

Description

Manufacturing method of polyester fiber {A MANUFACTURING METHOD OF POLYESTER YARN}

The present invention relates to a method for producing a polyester fiber, and more particularly, it is not only excellent in processability, but also exhibits sufficient resistance to external impact or deformation, which is very useful for industrial fibers such as ropes, belts, civil structures, etc. It relates to a method for producing a polyester fiber that can be.

Polyester resins are prepared by polymerizing terephthalic acid or dimethyl terephthalate with ethylene glycol.

Fibers made of polyester resins are increasingly being used as industrial fibers such as ropes, belts, base fabrics of coated fabrics such as tarpaulins or truck covers, and civil reinforcements. This is due to the excellent mechanical properties of polyester fibers.

In recent years, high strength polyester fiber which has high elasticity is calculated | required. In order to obtain polyester fibers that meet these requirements, a method of increasing the intrinsic viscosity of the polyester resin or increasing the draw ratio has been proposed.

Of these, the method of increasing the intrinsic viscosity of the polyester resin should increase the residence time during the solid-state polymerization process of the resin, which is directly connected to the cost increase, and the melt viscosity of the produced polyester resin is increased to control the processability during melt spinning There is a problem that is difficult.

On the other hand, as a method for increasing the draw ratio of the polyester fiber, using hot air or steam to fix the stretching point in the stretching section, or to install a latitude (hood) heater at the bottom of the spinneret or lengthen the delayed zone (Delayed zone) The method of adjusting the extending | stretching characteristic of resin provided and spun is used.

The method of fixing the stretching point is hardly effective when the stretching characteristics of the unstretched yarn itself before stretching are uneven.

In addition, the method using a heater or the like at the bottom of the spinning nozzle is advantageous to solve the orientation nonuniformity existing in the spun fiber, but the orientation nonuniformity of the undrawn yarn generated during the cooling process through the cooling process cannot be controlled. .

On the other hand, Japanese Patent Laid-Open No. 46-6459 and the like disclose a direct spinning drawing process in which spinning and stretching are performed in one continuous step. In this direct radiation drawing method, the spinning and drawing must be performed at the same time, so hot air is also used in the drawing process.

     The problem to be solved by the present invention is to solve the above problems, and to effectively solve the orientation non-uniformity of the melt-spun and cooled polyester non-drawn yarn, a method for producing a polyester fiber having excellent elasticity and strength during stretching To provide.

In order to achieve the above object, the manufacturing method of the polyester fiber according to the present invention,

(S1) melt spinning the polyester resin through a spinneret and cooling to prepare an unstretched yarn;

 (S2) preparing a tube having a passage extending in the longitudinal direction and maintained at 50 to 150 ° C., and heating the undrawn yarn by passing through the passage of the tube; And

(S3) heat treating and stretching the heated unstretched yarn.

In the manufacturing method of the polyester fiber which concerns on this invention, it is preferable that the intrinsic viscosity (IV) of the said polyester resin is 0.8-1.5.

In the method for producing a polyester fiber according to the present invention, the length of the tube is preferably 2 to 4 m.

In the method for producing the polyester fiber according to the present invention, the total draw ratio of the undrawn yarn is preferably 6 times or more, the LASE 5% value of the obtained polyester fiber is 5.5 g / d or more, and the strength is 10.0 g / d or more. And elongation at break is preferably 12% or less.

The present invention solves the orientation nonuniformity of the undrawn yarn by passing the melt-spun polyester undrawn yarn into a tube maintained at a predetermined temperature to be heated. Heat-treated polyester unstretched yarn has a good stretching uniformity, it can be easily produced polyester fibers having excellent properties of high elasticity, high strength when drawn.

Polyester fibers produced according to the present invention exhibits sufficient resistance to external impact or deformation, and thus can be very usefully used as industrial fibers such as ropes, belts, civil structures and the like.

     Hereinafter, the present invention will be described in detail. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

The manufacturing method of the polyester fiber which concerns on this invention is as follows.

First, the polyester resin is melt-spun through a spinneret and cooled to prepare an unstretched yarn (S1 step).

The intrinsic viscosity of the polyester resin to be used is preferably 0.8 to 1.5 in consideration of spinning workability and the physical properties of the fiber obtained. The intrinsic viscosity of the final polyester fiber obtained by melt spinning and stretching the polyester resin which has such an intrinsic viscosity becomes about 0.7-1.2 normally. When the intrinsic viscosity of the polyester resin is 0.8 or more, the physical properties of the fiber obtained are better, and when it exceeds 1.5, the workability is lowered, so that sufficient elongation may be difficult.

The melt spinning temperature is a temperature at which the polyester resin can be sufficiently melted and spun into a fibrous shape while minimizing thermal decomposition of the polyester resin, and can be appropriately determined according to the intrinsic viscosity of the polyester resin used. The spun fibrous polyester resin is produced unstretched yarn, for example, by cooling with quench air at 20 to 25 ° C. The prepared non-drawn yarn may be wound up in a winding machine and put into the next process.

The undrawn yarn cooled according to the step S1 is very uneven in the orientation of the molecular chains. Thereby, when extending | stretching unstretched yarn immediately, extending | stretching becomes nonuniform and the physical property of the fiber obtained will become bad.

 In order to solve this problem, the present invention extends in the longitudinal direction, and prepared a tube having a passage maintained at 50 to 150 ℃, and the undrawn yarn was passed through the passage of the tube and heated (step S2).

In this way, when the polyester non-drawn yarn is passed through a passage of a tube maintained at a predetermined temperature and heated, the orientation unevenness of the undrawn yarn is eliminated. The heat treated polyester unstretched yarn has a good stretching uniformity, and can increase the draw ratio of the unstretched yarn. That is, when extending | stretching the unstretched yarn which performed the heat processing and performed the orientation nonuniformity, the polyester fiber which has the outstanding physical property can be manufactured.

The length of the tube is not limited as long as it can be sufficiently heat treated so that the undrawn yarn passes and the orientation nonuniformity is eliminated, preferably 2 m or more, more preferably 2 to 4 m. The cross-sectional shape of the passage formed in the center of the tube is preferably circular or elliptical so that the undrawn yarn can run well, but other cross-sectional shapes such as squares and triangles are possible. By using such a tube, unstretched yarn can be stably heat treated with little energy.

If the temperature of the tube passage is less than 50 ° C., the molecular chains of the undrawn yarn cannot flow well, so that the effect of orientation uniformity is small. When the temperature of the tube passage exceeds 150 ° C., rapid crystallization proceeds to produce and grow many microcrystals. These microcrystals act as vulnerabilities in stretching. As a result, the strength is lowered, and problems such as cattle in terms of quality become remarkable, and in severe cases, it can cause cutting of the yarn, making it difficult to secure process stability.

As a method of maintaining the tube passage at the above-mentioned temperature, a method of maintaining hot air while blowing it into the tube passage is effective. In addition, a method of maintaining a proper temperature using a heater may be used.

Then, the unstretched yarn heated in the tube passage is stretched by heat treatment (step S3).

The undrawn yarn heated in the tube passage is continuously carried out according to the conventional drawing method of polyester fiber. That is, the temperature is set to allow the stretching, the stretching is carried out by passing the undrawn yarn between the rollers rotate at different speeds, the stretching of the undrawn yarn is preferably carried out in two steps in accordance with a conventional drawing method, It is not limited. The total draw ratio of the undrawn yarn is preferably 6 times or more so as to obtain a high strength polyester fiber. The stretched polyester fiber can be subjected to conventional heat setting treatments as necessary.

According to the above-mentioned manufacturing method, polyester fiber obtained by running unstretched yarn through a passage of a tube and undergoing a heat treatment and stretching process has high elasticity and high strength. The LASE 5% value of the polyester fiber is 5.5 g / d or more and the strength is high. It is preferable to manufacture 10.0 g / d or more and breaking elongation 12% or less.

These polyester fibers are used as monofilaments or multifilaments and are useful for industrial, in particular civil reinforcement or safety belts.

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Intrinsic Viscosity (IV)

After dissolving 0.1 g of a polyester resin for 90 minutes in a reagent (90 ° C.) in which phenol and 1,1,2,2-tetrachloroethanol were mixed at 6: 4 (weight ratio), a Ubbelohde viscometer was used. Transfer was carried out, it was maintained for 10 minutes in a 30 degreeC thermostat, and the fall second of the solution was calculated | required using a viscometer and an aspirator. The number of falling seconds of the solvent was also calculated in the same manner, and then the intrinsic viscosity (I.V.) value was calculated according to the intrinsic viscosity calculation method.

How to measure modulus and elongation of fiber

After the fibers were left in a constant temperature and humidity room at a standard condition, that is, a temperature of 25 ° C. and a relative humidity of 65% for 24 hours, the modulus and elongation of the fibers were measured by a tensile tester according to the method of ASTM D-885.

How to measure dry heat shrinkage

The fibers were allowed to stand for 24 hours in a constant temperature and humidity chamber of standard conditions, i.e., a temperature of 25 ° C and a relative humidity of 65%, followed by heat treatment for 5 minutes in an oven at 190 ° C. After removing the heat-treated fiber in the oven, it was left for 24 hours in a standard state, and the reduced shrinkage of the fiber was measured according to the following equation.

Shrinkage (%) = (L0-L1) / L0 × 100

In the above formula, L0 is the length measured under superload (0.01 g / d) after leaving the fiber for 24 hours in the above standard condition, and L1 is the superload ( Length of sample reduced under 0.01 g / d).

<Example 1 to 7>

Intrinsic viscosity 1.0 The polyester chip, the spinning temperature is 300 degrees, using a polymer gear pump with a discharge amount of 333g per minute to extrude the molten polymer through a nozzle with a hole diameter of 0.4mm and a hole of 192, the quenching air of 20 ~ 25 ℃ Undrawn yarn was prepared by cooling with. Subsequently, the undrawn yarn was passed through a tube passage of 4 m length filled with heated air, followed by drawing through a high-det roller maintained at temperatures of 90 ° C. and 130 ° C., and heating rollers maintained at 230 ° C. Heat treatment was performed. The speed | rate of GR4 of a high-det roller was 3,000 m / min, and it wound up at 1,000 denier fineness.

The temperature and the total draw ratio of the tube passages are shown in Table 1 below, and the physical property values measured for the obtained polyester fibers are shown in Table 1.

<Comparative Example 1 to 3>

It carried out similarly to the Example except having changed to the conditions of following Table 2. The physical property values measured about the obtained polyester fiber are shown in Table 2.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Spin tube
Hot air temperature (℃) 50 70 90 100 110 130 150 Total draw ratio 6.00 6.10 6.00 6.10 6.20 6.00 6.10 burglar 10.51 10.30 10.51 10.68 10.53 10.59 10.62 Shinto 10.10 9.34 10.29 9.30 9.48 9.12 8.81 LASE5% 5.45 5.47 5.77 6.28 5.22 6.41 6.47 Heat shrinkage 15.2 15.8 15.3 16.1 15.3 16.4 16.3 Exterior Good Good Good Good Good Good Good

Comparative Example 1 Comparative Example 2 Comparative Example 3 Temperature of tube passage not used 40 170 Total draw ratio 5.80 5.90 6.00 burglar 9.89 9.95 10.10 Shinto 11.14 11.2 11.42 LASE5% 4.74 4.95 5.50 Heat shrinkage 15.6 16.3 15.7 Exterior Poor (Mow) Poor (Mow) Poor (Mow)

Referring to the results of the table, the fibers of the examples were all stretched at a draw ratio of 6 times or more, and the physical properties such as breaking strength of the fiber, LASE 5% elastic modulus were all excellent.

On the other hand, the fiber of Comparative Example 1 has a low maximum draw ratio, it was difficult to implement high strength and high elasticity, it can be observed that a lot of defects (FLUFFY YARN) occurs in the product appearance state. It was found that the fiber of Comparative Example 2 did not have sufficient heat transfer for uniform orientation due to the low hot air temperature in the tube passage. The fiber of Comparative Example 3 had a problem such that the undrawn yarn was fused while passing through the passage because the hot air temperature of the tube passage was too high, resulting in poor processability.

Claims (5)

(S1) melt spinning and cooling a polyester resin having an intrinsic viscosity (IV) of 0.8 to 1.5 through a spinneret and cooling to prepare an unstretched yarn;
(S2) preparing a tube having a passage extending in the longitudinal direction and maintained at 50 to 150 ° C., and heating the undrawn yarn by passing through the passage of the tube; And
(S3) A method for producing a polyester fiber comprising the step of stretching the heated undrawn yarn. delete The method of claim 1,
Method for producing a polyester fiber, characterized in that the length of the tube is 2 to 4 m. The method of claim 1,
The total draw ratio of the non-drawn yarn is a method for producing a polyester fiber, characterized in that more than six times. The method of claim 1,
The LASE 5% value of the polyester fiber is 5.5 g / d or more, the strength is 10.0 g / d or more, the elongation at break is 12% or less.