KR20000046773A - Process for producing polyethylene-2,6-naphthalate fiber - Google Patents

Abstract

PURPOSE: Provided is a process for producing polyethylene-2,6-naphthalate fiber which has improved work property, mechanical property and heat property. Thereby, it is possible to produce polyethylene-2,6-naphthalate fiber which has excellent work property, mechanical property and heat property. CONSTITUTION: A process for producing a polyethylene-2,6-naphthalate fiber is obtained by multiple drawing steps. The first drawing step is drawn by the first drawing roller of 100-150°C and the second drawing roller. The second drawing step is drawn by the second drawing roller and the third drawing roller of 150-250°C. The rate of the first drawing step is 10-20% of total drawing rate. The rate of the second drawing step is 80-90% of total drawing rate.

Description

Method for producing polyethylene-2,6-naphthalate fiber

The present invention relates to a method for producing polyethylene-2,6-naphthalate fiber, and more particularly, to a method for producing polyethylene-2,6-naphthalate fiber having excellent mechanical and thermal properties.

Polyethylene terephthalate uses terephthalic acid in its synthesis, while polyethylene-2,6-naphthalate, which has a larger molecular structure and uses naphthalic acid in the polymer repeating unit using rigid naphthalic acid, is a naphthalate unit. Due to its large structure, crystals are more difficult to form than polyethylene terephthalate, and thus have a smaller density than polyethylene terephthalate, which is lighter, and the molecular chain is rigid, which has high strength, elastic modulus, and thermal stability.

The properties of polyethylene-2,6-naphthalate are suitable for acid-producing, such as belts and hoses, which require high strength and high flame resistance, and in particular, they exhibit optimum physical properties for tire cords. Conventional tire cord materials include polyethylene terephthalate, nylon, rayon, and aramid fibers, but rayon and aramid compounds cause environmental problems and require high manufacturing costs. Nylon and the like have problems in strength and stability at high temperatures.

On the other hand, polyethylene-2,6-naphthalate has a high disadvantage compared to polyethylene terephthalate or nylon in terms of price, but it shows high strength, heat resistance, and low heat shrinkage ratio, so that when the price / performance ratio becomes more competitive Starting from existing high-performance race tire cords, it is expected to replace many industrial materials used by polyethylene terephthalate and nylon.

Table 1 shows the properties of various tire cord yarns including polyethylene-2,6-naphthalate, and polyethylene-2,6-naphthalate has the advantage of using the melt spinning facility of the existing polyethylene terephthalate as it is. Also exhibits excellent properties in elastic modulus and heat shrinkage.

On the other hand, Table 2 compares the physical properties of tire cord paper made of such yarns, and shows that polyethylene-2,6-naphthalate has superior properties in specific strength, elastic modulus and heat shrinkage compared to polyethylene terephthalate and nylon.

; Comparison of properties of different industrial companies Kinds Polyethylene-2,6-naphthalate Polyethylene terephthalate nylon Rayon Aramid Production method Melt spinning play Solution liquid crystal Density (g / cm?) 1.36 1.39 1.14 1.52 1.44 Specific strength (g / d) 10 9 9 5 23 Elastic material (g / d) 360 110 50 125 560 Elongation (%) 8 14 15 12 4 Heat shrinkage (%) 177 ℃, 1 minute 4 8 10 6 〉 0.1

; Comparison of properties of different tire cords Kinds Polyethylene-2,6-naphthalate Polyethylene terephthalate nylon Rayon Aramid Specific strength (g / d) 8 7 8 5 16 Elastic material (g / d) 150 70 30 60 340 Heat Shrinkage (%) 177 ℃ One 4 7 One 0

As shown in Tables 1 and 2, polyethylene-2,6-naphthalate has excellent properties in many parts compared to polyethylene terephthalate and nylon, which currently occupy most of the tire cord paper, but still produces optimal spinning conditions and tire cord paper. The technology has not been established. This is because polyethylene-2,6-naphthalate has been studied relatively recently, and the molecular chain containing naphthalate units exhibits a different behavior from polyethylene terephthalate.

Therefore, in order to produce tire cord paper made of polyethylene-2,6-naphthalate, it is important to find the optimal spinning conditions in connection with the basic experiments on the polymer, that is, melt viscoelastic behavior and crystallization behavior.

First, the production of polyethylene terephthalate fibers containing 90 mol% or more of conventional polyester fibers, particularly naphthalene dicarboxylate units, and also having an intrinsic viscosity of 0.5 to 1.5, the temperature of the feed roller to 70 to 150 ℃, After extending | stretching so that temperature of a 1st extending | stretching roller may be 150-190 degreeC so that 1st stage extending | stretching may be 80 to 90% of full extension magnification, it extended | stretched so that it might become 10 to 20% of full extension magnification by 2nd stage extension.

Further, the fibers were heat-fixed at a temperature of the second stretching roller at 190 to 250 ° C.

However, in the drawing process described above, there is a disadvantage in that the operation and trimming and the properties of yarn are inferior due to poor operation.

Conventional techniques for producing such polyethylene-2,6-naphthalate fibers include Japanese Patent Application Laid-Open Nos. 48-77116, 48-64222, 50-16739, Japanese Patent Laid-Open No. 4-119119, and the like. have.

Japanese Laid-Open Patent Publication No. 48-77116 is characterized by extending the first draw ratio to 80-90% of the total draw ratio in order to improve the drawing conditions, and then performing the remaining draw in the second draw. It is stated that it is necessary to suppress the ratio from 0.001 to 0.02. However, in order to set the degree of unoriented orientation to 0.001 to 0.02, the inventors' results showed that the supply roller speed did not exceed 100 m / min, resulting in a very low productivity and poor operability.

So 48-64222 and 50-16739 describe the technique of increasing the speed of spinning very rapidly, but there are disadvantages that new investment of equipment is required and existing equipment cannot be utilized. It was only 8g / d level.

In Japanese Unexamined Patent Publication No. 4-119119, a method of using superheated steam for the first stage stretched yarn and the second stage stretched yarn is proposed, but a spinning speed similar to that of 48-77116 is required and a separate An apparatus is required, and hydrolysis due to the use of overheated steam is concerned.

The present invention is to solve the problems described above, it is an object of the present invention to provide a method for producing polyethylene-2,6-naphthalate fibers with improved operability, mechanical properties and thermal properties while using the existing equipment as it is. .

In order to solve the problems of the prior art, the present inventors continued the development of the example, and as a result, using the existing spinning equipment for polyethylene terephthalate as it is under special drawing conditions, there is no additional facility investment, while maintaining productivity and physical properties and operability. This led to the development of technology to produce this very good polyethylene-2,6-naphthalate fiber.

That is, the present invention provides polyethylene-2 so that the total draw ratio is 5.0 or more when producing polyethylene-2,6-naphthalate fibers having an intrinsic viscosity of 0.5 to 1.5, wherein the naphthalene dicarboxylate unit contains 90 mol% or more. A multi-stage stretch of 6-naphthalate unstretched fibers to improve the operability when producing polyethylene-2,6-naphthalate fibers having a strength of 8.0 g / d or more and a shrinkage rate of 4.5% or less. When spinning the naphthalate fibers, the rotational speed of the feed roller, that is, the spinning speed is wound at 100 to 1000 m / min, and is supplied to the subsequent first stretching roller, and the first stretching roller is in the temperature range of 100 to 150 ° C. The rotational speed is moderately faster than that of the supply rollers, and the yarns are fed to the second stretching roller at a speed of applying moderate tension, and the second stretching roller is at least 10 ° C higher than the first stretching roller. 1 stage The ratio to be not more than 20% of the total stretch ratio and stretching the first end, the third re-stretching rollers, and stretched more than the remaining 80% of the total draw ratio at a temperature range of 150~250 ℃, open and is characterized in that to set. The use of a fourth stretching roller to relieve tension to some extent is also effective.

Hereinafter, the present invention will be described in detail.

If the rotational speed of the feed roller is less than 100m / min, the final winding speed is also very slow, there is a disadvantage that the productivity is extremely low compared to the conventional polyethylene-2,6-naphthalate fiber. In addition, when the rotational speed of the feed roller is more than 1000m / min, the undrawn orientation is 0.1 or more, extremely difficult to draw, the draw ratio is low, the strength can not be expressed, the operation disadvantage is also extremely disadvantageous have.

When the temperature of the first stage drawing roller is less than 100 ° C., the glass transition temperature of polyethylene-2,6-naphthalate is below the glass transition temperature, and stretching is impossible at all. Formed, resulting in poor stretchability and operability.

The first draw ratio between the first draw roller and the second draw roller should be 20% or less of the total draw ratio. When the first draw ratio exceeds 20%, trimming starts to occur, and subsequent second draw is impossible and the physical properties are also drastically decreased.

The temperature of the second stage stretching roller is usually 10 ° C or more higher than the first stage stretching roller, and the second stretching ratio between the second stage stretching roller and the second stage stretching roller should be 80% or more of the total stretching ratio. .

Embodiments of the present invention are as follows.

<Example>

(a) Four rolls of polyethylene-2,6-naphthalate unstretched yarn having an intrinsic viscosity of 0.61 and a fineness of 760d / 136f were wound four times on a supply roller at room temperature rotating at 700 m / min, and then heated to 130 ° C. to 705 m / min. It winds and rotates 4 times to a rotating 1st extending roller.

Thereafter, by winding seven times on a second stretching roller heated at 160 ° C. and rotating at 1,000 m / min, one step stretching is performed, and again, the stretched yarn is heated at 160 ° C. and rotated at 3,300 m / min to a third stretching roller. Winding seven times is performed in two stages of stretching, where the stretching ratio is 1st stretching to 12% of the total stretching ratio, and the second stretching is 88% of the total stretching ratio.

The two-stage stretched yarn thus obtained is wound around the fourth stretching roller heated to 110 ° C. and rotated at 3,250 m / min, seven times, and heat-set while relieving the tension applied to the yarn.

The properties of the drawn yarn thus obtained are shown in Table 3.

Experiment number One 2 3 4 5 burglar 6.79 6.83 7.06 7.56 7.34 Shinto 13.3 9.63 8.0 10.1 11.0 Dry heat shrinkage 2.1 2.3 2.6 2.9 2.7 Melting point 270.2 270.9 271.5 272.7 272.0

(b) Four rolls of polyethylene-2,6-naphthalate unstretched yarn having an intrinsic viscosity of 0.74 and fineness of 770d / 136f were wound four times on a rotational feed roller rotating at 650 m / min, and then heated to 130 ° C. to 655 m / min. It winds and rotates 4 times to a rotating 1st extending roller.

Thereafter, by winding seven times on a second stretching roller heated at 160 ° C. and rotating at 1,000 m / min, one step stretching is performed, and again, the stretched yarn is heated at 160 ° C. and rotated at 3,300 m / min to a third stretching roller. Winding seven times is performed in two stages of stretching, in which the stretching ratio is one stage stretching to 14% of the total stretching ratio, and the second stage stretching is 86% of the total stretching ratio.

The two-stage stretched yarn thus obtained is wound around the fourth stretching roller heated to 110 ° C. and rotated at 3,250 m / min, seven times, and heat-set while relieving the tension applied to the yarn.

The properties of the drawn yarn thus obtained are shown in Table 4.

Experiment number One 2 3 4 burglar 7.46 7.89 8.01 8.26 Shinto 10.8 10.3 10.6 10.1 Dry heat shrinkage 2.6 2.6 2.7 2.8 Melting point 272.3 273.6 273.6 273.9

(c) 4 rolls of polyethylene-2,6-naphthalate unstretched yarn having an intrinsic viscosity of 0.84 and a fineness of 760d / 136f were wound four times on a rotational feed roller rotating at 650 m / min, and then heated to 130 ° C. to 655 m / min. It winds and rotates 4 times to a rotating 1st extending roller.

Thereafter, by winding seven times on a second stretching roller heated at 160 ° C. and rotating at 1,000 m / min, the first drawing is carried out, and the stretched yarn is heated at 160 ° C. and rotated at 3,480 m / min to a third stretching roller. Winding seven times is performed in two stages of stretching, where the stretching ratio is 1st stretching to 12% of the total stretching ratio, and the second stretching is 88% of the total stretching ratio.

The two-stage stretched yarn thus obtained is wound around the fourth stretching roller heated to 110 ° C. and rotated at 3,470 m / min, seven times, and heat-set while relieving the tension applied to the yarn.

The properties of the drawn yarn thus obtained are shown in Table 5.

Experiment number One 2 3 4 burglar 8.01 8.26 8.45 8.69 Shinto 11.3 10.3 9.4 8.8 Dry heat shrinkage 2.6 2.7 2.9 3.3 Melting point 273.5 273.8 274.3 275.1

(d) Four rolls of polyethylene-2,6-naphthalate unstretched yarn having an intrinsic viscosity of 0.91 and a fineness of 760d / 204f were wound four times on a rotational feed roller rotating at 660 m / min, and then heated to 130 ° C. to 670 m / min. It winds and rotates 4 times to a rotating 1st extending roller.

Thereafter, the first drawing is performed by winding seven times on a second drawing roller heated to 160 ° C. and rotating at 1,000 m / min, and the drawn yarn is further wound on a third drawing roller heated to 160 ° C. and rotating at 3,240 m / min. Winding seven times is performed in two stages of stretching, where the stretching ratio is 13% of the first stretching ratio and 87% of the total stretching ratio.

The two-stage stretched yarn thus obtained is wound around the fourth stretching roller heated to 110 ° C. and rotated at 3,250 m / min, seven times, and heat-set while relieving the tension applied to the yarn.

The properties of the drawn yarn thus obtained are shown in Table 6.

Experiment number One 2 3 4 burglar 8.56 8.78 8.91 9.05 Shinto 11.1 9.8 8.6 8.4 Dry heat shrinkage 2.65 2.46 2.32 2.19 Melting point 274.7 275.41 276.2 277.9

<Comparative Example>

In each experiment having the intrinsic viscosity of the examples, the first stage drawing was performed to be 80% or more. In the case of intrinsic viscosity 0.61, 0.74 and 0.84, the winding itself was impossible. In case of intrinsic viscosity 0.91, winding was possible, but frequent trimming and physical property deterioration were involved. In the case of the intrinsic viscosity 0.91, the properties of the drawn yarn are shown in Table 7.

Experiment number One 2 3 4 burglar 7.12 7.23 7.26 7.31 Shinto 14.6 13.9 13.4 12.7 Dry heat shrinkage 2.12 2.57 2.89 3.01 Melting point 271.7 272.1 272.6 273.4

Polyethylene-2,6-naphthalate fibers made from the present invention are suitable for various applications requiring high tensile strength, resistance to tensile deformation and high heat resistance. In particular, it shows excellent performance for applications requiring high zonal stability, such as tire cords, industrial hoses and belts.

Claims (1)

In producing polyethylene-2,6-naphthalate fibers by melting, spinning and stretching, the first stretching is performed by 10 to 20% of the total stretching ratio by the first stretching roller and the second stretching roller at 100 to 150 占 폚. Next, the second stretching is performed by the second stretching roller and the third stretching roller at 150 to 250 ° C. to 80 to 90% of the total stretching ratio, wherein the polyethylene-2,6-naphthalate fiber is produced.