JPH0441769A - Drawing of fiber - Google Patents

Abstract

PURPOSE:To obtain a drawn yarn having excellent initial elastic modulus and tensile properties compared with those of yarn produced by conventional hot- drawing process by irradiating a thermoplastic fiber with a specific dose of electron ray in at least a part of the drawing zone. CONSTITUTION:A thermoplastic fiber selected from fibers of polyester, polyamide, polyethylene, polyvinyl chloride and polyvinyl alcohol resins or a blended fiber or a fiber conjugated in the cross section is drawn while radiating electron ray at a dose of 0.5-100Mrad to at least a part of the drawing zone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drawing method for producing fibers with excellent initial elastic modulus.

[Prior art] Conventionally, methods for drawing thermoplastic fibers include cold drawing, which utilizes heat generated by deformation of the polymer during drawing, or drawing with polymer molecular chains activated by external heating. A hot drawing method is common, and the latter hot drawing method has been widely adopted as a means for obtaining high modulus fibers.

Specific means for hot stretching include a method using high-temperature steam, a method using a high-temperature hot plate, and a method using hot rolls.

[Problems to be Solved by the Invention] However, these methods all involve stretching by high-temperature heating, and crystallization occurs before high orientation is achieved. The reality was that they were doing so.

As a result, there was a drawback that significant molecular chain scission occurred during stretching.

The purpose of the present invention is to improve the drawbacks of the above conventional hot stretching method,
By achieving high orientation while suppressing crystallization during stretching, the aim is to provide a drawn yarn with excellent tensile properties and less molecular chain breakage during stretching.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration.

That is, the method for drawing fibers of the present invention is characterized in that when drawing thermoplastic fibers, at least a portion of the drawing region is irradiated with an electron beam.

[Function] The present invention was completed after discovering that when thermoplastic fibers made of crystalline synthetic resin are drawn under specific conditions, crystallization is unexpectedly suppressed and only the orientation progresses. It is something.

That is, the present inventors have discovered that when polyester fibers are stretched while being irradiated with electron beams, the molecular orientation becomes significantly higher even though crystallization does not progress that much. Based on this fact, similar studies were conducted on thermoplastic fibers made of other crystalline synthetic resins, and highly oriented fibers could be obtained in all cases.
This has led to the present invention.

The thermoplastic fibers used in the present invention are fibers made of at least one type of crystalline synthetic resin selected from polyester resins, polyamide resins, polyethylene resins, polyvinyl chloride resins, and polyvinyl alcohol resins. can do.

The polyester fibers mentioned here include, for example, polyethylene terephthalate, polybutylene terephthalate, or copolymers obtained by copolymerizing these with a third component such as isophthalic acid sulfonate, adipic acid, isophthalic acid, polyethylene glycol, or the above-mentioned polymers. Fibers obtained by blending polymers such as polyethylene glycol can be used, but are not limited thereto.

Examples of polyamide fibers include polyamides in which 75% or more of the repeating units are caproamide units;
For example, nylon 6, nylon 6.6, nylon 6.
Fibers made of resins such as 10, nylon 7, nylon 11, and nylon 12 can be used. Among these, fibers made of nylon 6 and nylon 6.6 are particularly preferred.

Polyethylene fibers include, for example, those whose main component is polyethylene, with small amounts of other alkenes such as propylene, butylene, pentene, hexene, 4-methylpentene, or vinyl monomers that can be copolymerized with ethylene. It is possible to use fibers obtained by copolymerizing one or more of the following, or by mixing a small amount of polyolefin such as polypropylene or polybutene-1.

In addition, polyvinyl chloride fibers include those whose main component is polyvinyl chloride, such as copolymers of vinyl chloride and olefins such as ethylene, propylene, isobutylene, or styrene, or vinyl chloride and diene compounds, For example, copolymers with butadiene, isoprene, etc., or vinyl chloride and acrylic acid,
It is possible to use fibers obtained from copolymers with methacrylic acid or halogenated olefins, or ethylene-vinyl acetate copolymers.

These fibers may also contain additives such as plasticizers, stabilizers, fillers, antioxidants, or ultraviolet absorbers.

Examples of polyvinyl alcohol fibers include fully saponified polyvinyl alcohol, olefin monomers such as ethylene, propylene, styrene, acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, and itaconic acid in the main chain. Polyvinyl alcohol fibers copolymerized with a small amount can be used.

In addition, a mixed yarn made of a combination of at least two types selected from fibers made of polyester resin, polyamide resin, polyethylene resin, polyvinyl chloride resin, and polyvinyl alcohol resin can also be used as the thermoplastic fiber of the present invention. can be used.

Further, a circular cross-section composite fiber made of a combination of at least two of the above-mentioned resins can be used as the thermoplastic fiber of the present invention. For example, it is possible to use a composite fiber composed of two or more different resins in the cross-sectional direction, such as a core-sheath structure, a side-by-side structure, or an irregular arrangement structure found in polymer alloys.

In the present invention, the above-mentioned thermoplastic fiber yarn is irradiated with an electron beam in the drawing region, and due to the irradiation with the electron beam, the polymer molecules constituting the fiber are extremely susceptible to mutual movement. As a result, it is thought that smooth stretching can be performed.

In fact, if fibers that can be drawn in an electron beam are drawn outside the system, an extremely large amount of force is required and the fibers will eventually break.

The electron beam used in the present invention preferably has an irradiation dose of 0.
5-10 Q Mrad, preferably 5-50 Mrad
Use a range of . The irradiation dose is 0.5 Mrad
If it is less than that, the ease of movement of polymer molecules is not sufficient,
On the other hand, if the irradiation dose is l
If Q Q Mrad is exceeded, the polymer molecules will be cut, and as a result, the fibers will be easily cut and it will be difficult to draw them.

The stretching device used in the present invention may have any structure and is not particularly limited as long as it is equipped with a yarn feeding mechanism before and after the electron beam irradiation section.

Thermoplastic drawn fibers obtained by this method are characterized by superior initial elastic modulus compared to hot drawn yarns produced by conventional techniques.

[Example] The present invention will be explained below with reference to Examples.

In addition, the initial elastic modulus shown in the examples is JIS L-
1977.

Examples 1 to 5, Comparative Examples 1 to 3 A semi-drawn polyethylene terephthalate yarn (140 denier 36 filament) spun by a known method and wound at 3000 m/min was placed on yarn feeding rollers before and after an electron beam irradiation device. Stretching was carried out under the conditions shown in Table 1 using the system shown in FIG.

For comparison, the semi-drawn yarn was drawn under the conditions shown in Table 1 by the conventional method shown in FIG. 2 using a hot plate without electron beam irradiation.

The initial elastic modulus of these drawn yarns was measured and the results are shown in Table 1.

As is clear from the results in Table 1, all of the yarns of the Examples had drawn yarns with higher elastic modulus than those of the Comparative Examples, which were drawn by conventional hot plate stretching.

[Effects of the Invention] According to the present invention, it is possible to provide a drawn yarn having extremely excellent initial elastic modulus and tensile properties as compared to conventional hot drawing methods.

[Brief explanation of the drawing]

FIG. 1 is a process schematic diagram showing an embodiment of the fiber stretching method of the present invention, and FIG. 2 is a process schematic diagram showing a conventional hot plate stretching method. Y: Yarn 1: Package 2: 10th-La 3: Electron beam irradiation section (effective irradiation length = 10 countries) 4: 20th-
La 5: Winding section 6: Hot plate (effective length = 10 marks) Patent applicant Toshi Co., Ltd.

Claims (5)

[Claims] (1) A method for stretching thermoplastic fibers, which comprises irradiating at least a portion of the stretching region with an electron beam when stretching the thermoplastic fibers. (2) The thermoplastic fiber is a fiber made of at least one selected from polyester resin, polyamide resin, polyethylene resin, polyvinyl chloride resin, and polyvinyl alcohol resin ( 1) The method for drawing the fibers described above. (3) The method for drawing fibers according to claim (1), wherein the thermoplastic fiber is a mixed yarn. (4) The method for drawing fibers according to claim (1), wherein the thermoplastic fibers are cross-sectional composite fibers. (5) The method for drawing fibers according to claim (1), wherein the electron beam has an irradiation dose in the range of 0.5 to 100 Mrad.