KR20010060489A - Process for preparing a polyester yarn of high strength-low shrinkage and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A polyester yarn having high strength and low shrinkage(in dry heat), and a manufacturing method thereof are provided. CONSTITUTION: The polyester yarn is obtained by a process containing the steps of: melt-spinning polyester polymer having 0.75-0.90 of inherent viscosity; cooling rapidly; passing through godet rollers(GR1, GR2, GR3); passing through a godet roller(GR4) having at least 240deg.C of surface temperature, and at least 220deg.C of atmospheric temperature, and then heat-drawing; passing through a godet roller(GR5), and then relaxing; and winding. The polyester yarn is characterized by at least 7.0g/denier of strength and below 3.0% of low contracting rate(in dry heat)(190deg.C x 10minutes).

Description

Process for preparing a polyester yarn of high strength-low shrinkage and manufacturing method

The present invention relates to industrial high strength, low shrinkage polyester yarn and a method for manufacturing the yarn in a continuous process, wherein the continuous process is a series of stretching, heat treatment, relaxation, winding process after melt spinning the polyester polymer Say it is.

The prior art has been able to minimize the shrinkage of the yarn produced by adjusting the relaxation conditions to remove residual shrinkage of the polyester yarns during stretching, but always accompanied a significant drop in strength.

Therefore, the development of low shrinkage yarns without deterioration of strength has been the subject of research for a long time, and related foreign patents are US Patents 4,251,481 and 4,349,501.

Other manufacturing methods besides the continuous process are two-stage process. This method was developed by separating spinning process, stretching process and relaxation process, which resulted in low shrinkage and proper strength, but continuous process was preferred because of enormous equipment cost. It is true.

The present invention aims to provide a method for producing a high strength, low shrinkage polyester yarn in a one-step continuous process and a high strength, low shrinkage polyester yarn produced by the above method.

1 is a manufacturing process schematic diagram of the present invention.

Explanation of symbols on the main parts of the drawings

A: Hot Box, B: Hot Air Attacher, C: Air Interlock Device,

D: cooling zone, GR ₁ to GR ₅ : high speed roller

The present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, the multifilament yarns are spun from the molten polymer to pass through the quench zone (D).

The unstretched yarn which has passed through the quench zone D is passed through the unheated gourd roller GR ₁ to apply some tension.

After passing through the gourd roller (GR ₂ ) heated to an appropriate temperature, go through the gourd roller (GR ₃ ) that is a stretching roll.

The high-pressure roller GR ₄ is a roller for providing heating, stretching and relaxation. The surface of the roller is a mat type, and the surface temperature is 240 ° C or higher.

The roller is surrounded by a heat box (A) heat-insulated to prevent heat dissipation. A hot air blower (B) is installed inside the heat box (A) to supply hot air from the outside. To maintain the temperature of the air in the heat box (A) above 220 ℃.

The drawing yarn which has passed through the high roller (GR ₄ ) is passed through the loose roller (GR ₅ ) to remove the residual shrinkage of the yarn, and then wound up.

The residence time of the yarn in the heat box A is appropriate from 0.30 to 0.50 seconds.

From this process, a relaxation rate of up to 17% can be given, and ultra low shrinkage yarns having a dry heat shrinkage (190 ° C. for 10 minutes) of 3.0% or less can be produced.

The polyester yarn produced according to the present invention can be widely used for applications such as reinforcement of the roofing material, because shrinkage by heat at a high temperature is small.

The intrinsic viscosity of the polymer is a convenient measure of the degree of polymerization and molecular weight, and the intrinsic viscosity of the polyester used in the present invention is 0.79, with a proper intrinsic viscosity of 0.75 to 0.90.

When the strength of the yarn produced from the present invention is 7.0 g / denier or more and the shrinkage is 190 ° C., the sample of the yarn is heat-treated for 10 minutes under no tension, and the degree of shrinkage is expressed as a percentage. 3.0% or less.

Comparative Example 1

In order to set the reference for the effect of improving the shrinkage rate, the comparative yarn was first treated without hot air spraying inside the hot box A.

Process conditions are shown in Table 1 below.

<Table 1>

Gauze Roller Roller speed (m / min) Roller temperature (℃) GR ₁ 460 - GR ₂ 480 97 GR ₃ 1900 125 GR ₄ 2650 240 GR ₅ 2380-2570 140

The residence time of the yarn in GR ₄ was about 0.35 seconds, and the speed of GR ₅ ranged from 2380 m / min to 2570 m / min, with 3% to 10% relaxation.

Physical properties of the yarn prepared under the above conditions are shown in Table 2 below.

<Table 2>

Sample name % Relaxation New Section (%) Strength (g / denier) Shrinkage (%) A 3 18.2 8.80 5.10 B 4 19.0 8.61 4.98 C 5 19.8 8.30 4.73 D 6 21.0 8.27 4.56 E 7 22.1 8.06 4.27 F 8 23.0 7.90 3.99 G 9 24.6 7.91 3.81 H 10 24.9 7.75 3.62

Comparative Example 2

The comparative yarn was processed in the state which maintained the internal temperature at about 210 degreeC by spraying hot air of 400 degreeC inside the hot box A.

Process conditions are the same as in Comparative Example 1, the physical properties are shown in Table 3 below.

<Table 3>

Sample name % Relaxation New Section (%) Strength (g / denier) Shrinkage (%) A 3 18.5 8.83 5.30 B 4 18.9 8.58 5.01 C 5 20.0 8.40 4.69 D 6 20.9 8.15 4.60 E 7 22.6 8.00 4.30 F 8 23.3 7.89 3.85 G 9 24.9 7.90 3.79 H 10 25.0 7.87 3.71

From the above results it can be seen that even if the temperature in the hot box (A) to maintain a temperature of 210 ℃ to 400 ℃ is not much improvement effect of the shrinkage.

Comparative Example 3

When hot air of 600 ° C. was sprayed inside the hot box A to maintain the internal temperature at 250 ° C. or more, continuous operation was impossible due to trimming.

Example 1

Table 4 below shows the spinning conditions when the temperature in the hot box A is maintained at 220 ° C by spraying hot air at 450 ° C.

<Table 4>

Gauze Roller Roller speed (m / min) Roller temperature (℃) GR ₁ 460 - GR ₂ 480 97 GR ₃ 1900 125 GR ₄ 2650 240 GR ₅ 2200-2570 140

The residence time of the yarn in GR ₄ was about 0.35 seconds, and the velocity of GR5 ranged from 2200 m / min to 2570 m / min, with 3% to 17% relaxation.

Physical properties of the yarn produced from the above conditions are shown in Table 5 below.

<Table 5>

Sample name % Relaxation New Section (%) Strength (g / denier) Shrinkage (%) A 9 25.2 7.84 3.29 B 10 25.3 7.80 2.98 C 11 25.9 7.75 2.67 D 12 26.7 7.59 2.44 E 13 26.5 7.40 2.40 F 14 27.1 7.20 2.31 G 15 27.0 7.01 2.15 H 16 27.4 6.99 2.03 I 17 27.5 6.90 1.95

Experimental results it can be seen that the polyester yarns produced under the above conditions reduced the shrinkage rate by at least 0.5% at the same relaxation rate than the yarns prepared in Comparative Example 1, Comparative Example 2.

Example 2

Table 6 below shows the physical properties of the yarn when Example 1 and spinning conditions were kept the same and the temperature in the hot box A was maintained at 230 ° C. by spraying 500 ° C. hot air.

<Table 6>

Sample name % Relaxation New Section (%) Strength (g / denier) Shrinkage (%) A 9 25.7 7.87 3.25 B 10 25.5 7.74 2.90 C 11 26.5 7.60 2.57 D 12 26.9 7.36 2.40 E 13 27.5 7.11 2.40 F 14 28.0 6.98 2.27 G 15 28.0 6.80 2.10 H 16 28.4 6.79 1.99 I 17 28.5 6.70 1.95

Example 3

Table 7 below shows the physical properties of the yarn when the spinning conditions were kept the same as in Example 1 and the hot air at 550 ° C. was sprayed to maintain the temperature in the hot box A at 240 ° C.

<Table 7>

Sample name % Relaxation New Section (%) Strength (g / denier) Shrinkage (%) A 9 26.3 7.75 3.23 B 10 26.8 7.60 2.91 C 11 27.0 7.47 2.54 D 12 27.0 7.40 2.38 E 13 27.5 7.32 2.35 F 14 27.9 7.10 2.22 G 15 28.6 6.89 2.04 H 16 28.8 6.80 1.92 I 17 29.5 6.80 1.90

Unlike the case of Comparative Example 3, the continuous operation was possible under the above conditions, and the overall shrinkage rate was reduced by 0.5% or more than that of Comparative Example 1 and Comparative Example 2 for each relaxation rate.

The present invention has a strength of 8.0g / denier or more by thermally stretching while maintaining the surface temperature of the hot-rolled roller GR _{4 to be} stretched to 240 ° C or higher and then relaxing it to 9% or more in the high-rolled roller GR ₅ , 190. High strength, high shrinkage polyester yarns having a shrinkage of 3% or less under dry heat treatment conditions of 10 ° C. × 10 minutes can be produced in a continuous process.

Claims (3)

Surface temperature in the manufacture of high strength low shrinkage polyester yarn in a continuous process of melt spinning, quenching, quenching and passing through a multi-stage high-pressure roller, stretching and heat-treating the polyester polymer having an intrinsic viscosity of 0.75 to 0.90. is as 9-17% passed through a 240 ℃ than godet rollers (GR ₄₎ sikidoe godet rollers (GR ₄₎ and then the godet roller to a heat treatment to the yarn by maintaining the ambient temperature above 220 ℃ of (GR ₅₎ passing through the A method of manufacturing a high strength, low shrinkage polyester yarn characterized by relaxation. High strength, low shrinkage polyester yarn that satisfies all of the following properties next Strength: 7.0g / denier or more Dry heat shrinkage: Below 3.0% (190 ° C × 10 minutes) The high-strength, low-shrink polyester yarn according to claim 1, wherein the high-pressure roller GR ₄ is placed in an insulated heat box and blown with hot air at 450 ° C to 550 ° C. Way.