JP2001172821A - Production of polyoxymethylene fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an extremely strong fiber having heat resistance, abrasion resistance and chemical resistance inherent to a polyoxymethylene stably for a long time in high speed. SOLUTION: This method for producing a polyoxymethylene fiber is to melt extrude the polyoxymethylene in a condition satisfying a specific condition, draw the undrawn fiber in >=200 m/min speed, continuously draw the fiber in >=4 times and wind up the fiber in 1,200 m/min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength polyoxymethylene fiber at high speed and with good operability.

[0002]

2. Description of the Related Art Polyoxymethylene is a polymer having excellent heat resistance, abrasion resistance and chemical resistance. The polymer itself is a known polymer as described in, for example, JP-A-6-211953. It is widely used as an engineering plastic for molded products such as gears.

[0003] Polyoxymethylene fibers have also been proposed. As a method for producing polyoxymethylene fibers, for example, Japanese Patent Publication No. 55-22566 discloses an elastic recovery method in which stretching and heat treatment are performed in a specific temperature range. Japanese Patent Application Laid-Open No. 60-52618 discloses a method of obtaining a fiber having a high modulus of elasticity, a method of performing multi-stage drawing of an undrawn yarn once wound at low speed to obtain a high-strength high-modulus fiber, No. 113823 discloses a method of melt spinning using polyoxymethylene having a melt viscosity in a specific range as a raw material.

[0004] However, the fiber obtained by the method disclosed in Japanese Patent Publication No. 55-22566 has a very low tensile strength. The method described in Japanese Patent Application Laid-Open No. 60-52618 has a problem that the production speed is low because the undrawn yarn once wound is subjected to multi-stage drawing at a low speed. Also, JP-A-8-
In the method of JP-A-113823, since polyoxymethylene having a low molecular weight is used as a raw material, the strength is about 4 g / d, and it has been difficult to use it for industrial materials.

[0005] As described above, no method has been proposed for obtaining polyoxymethylene fibers having high strength and suitable for use in industrial materials with good operability.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a high-strength fiber having heat resistance, abrasion resistance and chemical resistance characteristic of polyoxymethylene for a long time. It is an object of the present invention to provide a manufacturing method that can be manufactured at high speed at high speed.

[0007]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have conducted intensive studies on the mechanism of drawing a polyoxymethylene undrawn yarn from both the structure and physical properties. He discovered that the state of the drawn yarn and the drawing conditions were important factors for expressing the physical properties of the polyoxymethylene fiber, and melt-extruded the polyoxymethylene copolymer under specific conditions, and continuously drawn the undrawn yarn. The state and uniform stretching are performed by controlling the stretching conditions well, and it has been found that high-strength fibers can be obtained with good operability, and the present invention has been achieved.

That is, the present invention provides a method for producing a polyoxymethylene fiber, comprising melting a polyoxymethylene copolymerized with 0.1 to 10.0 mol% of an oxyethylene component under a condition satisfying the formula (1), The yarn spun and spun under the conditions satisfying the formula (2) is taken up at a take-up speed of 200 m / min or more and stretched 4.0 times or more.
A gist of the present invention is a method for producing polyoxymethylene fiber, which is characterized by winding at a speed of at least m / min. 1800 ≦ T × t ≦ 4800 (1) Equation T: Melting temperature (° C.) t: Melting time (minute) 50 ≦ df ≦ 500 (2) Equation df = πρD ² s / 4q ρ: Polymer melt density (g / cm) ³ ) D: Nozzle hole diameter (mm) s: Take-off speed (m / min) q: Single hole discharge amount (g /
Minutes)

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polyoxymethylene that forms the polyoxymethylene fiber of the present invention is a polymer starting from formaldehyde or trioxane, and is obtained by copolymerizing 0.1 to 10.0 mol% of ethylene oxide as a copolymer. By including the copolymer component, the thermal stability is improved as compared with the homopolymer, and the rate of crystallization that occurs in the process of cooling the molten polymer is reduced. There is an effect that high strength can be achieved by orientation.

If the amount of the copolymer component is less than 0.1 mol%, the above effects cannot be exerted. If the amount exceeds 10.0 mol%, the characteristics (heat resistance, abrasion resistance, chemical resistance, etc.) of the polyoxymethylene are obtained. Is impaired.

The copolymer may contain additives such as various pigments, antistatic agents and plasticizers as long as the effects are not impaired.

Next, this copolymer is prepared by adding 1800 ≦ T
× t ≦ 4800 (T: melting temperature (° C.) t: melting time from supply to extrusion (minutes)).

When T × t is less than 1800, it is difficult to completely melt and extrude the polymer, while T × t is
If it exceeds 4800, thermal decomposition or modification of the polymer may occur, making it difficult to operate continuously, and the physical properties of the obtained fiber also deteriorate.

The spinning conditions and the conditions for discharging the polymer melted under the above conditions from the nozzle are as follows.
≦ df ≦ 500. df = πρD ²
s / 4q, the polymer melt density (ρ: g / cm ³ ),
The relationship between nozzle hole diameter (D: mm), take-off speed (s: m / min), and single-hole discharge amount (q: g / min). Until the molten polymer extruded from the nozzle hole solidifies by cooling. Is an index of the deformation of. Here, the polymer melt density is a value obtained by measuring and converting a specified volume and a weight at a temperature at which melting is performed.

If the df is less than 50, it is difficult to take out a uniform yarn. If the df is more than 500, the deformation at the time of the take-up becomes large, resulting in thread breakage and uniform yarn cannot be obtained. Etc. cause problems.

The spun yarn is cooled and, if necessary, an oil agent is applied. The yarn take-off speed, which is a factor defining the above df, needs to be 200 m / min or more. If the speed is less than 200 m / min, the yarn speed is low.
It is difficult to obtain a uniform yarn quality. Further, the productivity is low and the cost is disadvantageous.

Further, it is necessary to continuously stretch the undrawn yarn melt-spun after passing through a take-up roller. In the present invention, it is effective to carry out a drawing treatment before completely cooling the spun yarn, and the yarn temperature is preferably room temperature or higher, preferably 30 ° C. or higher. This is because, when the yarn is completely cooled, crystallization proceeds, and the drawing treatment may be difficult.

The stretching ratio in the stretching process must be 4 times or more. If the ratio is less than 4 times, the orientation of the molecular chains does not proceed sufficiently, and it is difficult to obtain high-strength fibers. As a specific stretching method, it is preferable that the stretching is performed in a multi-stage manner between a plurality of rollers, and at this time, the yarn is heated by using a heating roller or a heater is provided between the rollers.

The stretched yarn is 120
It is preferable to wind up at a speed of 0 m / min or more. 120
If it is less than 0 m / min, the draw ratio will be less than 4 times, the orientation during stretching will not proceed sufficiently, and a high-strength fiber will not be obtained. Then, in order to improve the operability, it is preferable to set the winding speed to 2000 m / min or more.

[0020]

The present invention will be described below in more detail with reference to examples. In addition, each physical property value in an Example is measured by the following method. a) Polymer melt density Measured by the method described above. b) Strength Using a Shimadzu Autograph DSS-500, sample length 3
The average value measured under the conditions of 0 cm, a grip interval of 5 cm, and a tensile speed of 30 cm / min was defined as the fiber strength. c) Quality of yarn-making properties Continuous spinning was performed for 24 hours, and the evaluation was made in the following two stages according to the conditions such as yarn breakage and winding of a single yarn to a roller during the spinning. ：: good ×: bad

Example 1 A chip of a polyoxymethylene copolymer in which ethylene oxide was copolymerized at 1.6 mol% was supplied to an extruder, and melted at 220 ° C. for 10 minutes in the extruder. It was extruded from a spinneret having 48 mm holes at a single hole discharge rate of 1.1 g / min, cooled in air, applied with an oil agent, and taken off at a speed of 500 m / min. Subsequently, the yarn is first heated with a 150 ° C heating roller.
The film was stretched 5.0 times, and further stretched 1.2 times with a heating roller at 180 ° C. to make the total stretch ratio 6.0 times and wound at a speed of 3000 m / min. Table 1 shows the evaluation of the physical properties and the spinning properties of the obtained fibers.

Examples 2-3, Comparative Examples 1-3 As shown in Table 1, various values at the time of melting and spinning, stretching ratio,
The procedure was performed in the same manner as in Example 1 except that the winding speed was changed. Table 1 shows the evaluation of the physical properties and the spinning properties of the obtained fibers.

[0023]

【table 1】

As is clear from Table 1, in Examples 1 to 3, high strength polyoxymethylene fibers were obtained with good spinning properties. On the other hand, in Comparative Example 1, the value of the melting time was too large, Txt exceeded 4,800, the polymer was thermally degraded, and yarn breakage occurred frequently, and fibers could not be obtained. Comparative Example 2
Since df exceeded 500, deformation at the time of take-up became large, thread breakage occurred frequently, and stretching could not be performed. In Comparative Example 3, since the stretching ratio was less than 4 times,
The obtained fiber had low strength.

[0025]

According to the method for producing polyoxymethylene fiber of the present invention, polyoxymethylene fiber which is high in strength and can be sufficiently used for various industrial materials can be produced at high speed similarly to synthetic fibers such as nylon and polyester. And it can be obtained stably.

Claims (1)

[Claims] 1. A method for producing a polyoxymethylene fiber, wherein the oxyethylene component is 0.1 to 10.0 mol.
1% of the copolymerized polyoxymethylene is melted under the condition satisfying the formula (1), spun under the condition satisfying the formula (2), and the spun yarn is taken off at a take-up speed of 200 m / min or more, A method for producing a polyoxymethylene fiber, comprising drawing the film to 4.0 times or more and winding it up at a speed of 1200 m / min or more. 1800 ≦ T × t ≦ 4800 (1) Equation T: Melting temperature (° C.) t: Melting time (minute) 50 ≦ df ≦ 500 (2) Equation df = πρD ² s / 4q ρ: Polymer melt density (g / cm) ³ ) D: Nozzle hole diameter (mm) s: Take-off speed (m / min) q: Single hole discharge amount (g /
Minutes)