JPS60445B2 - Synthetic fiber manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the drawability of thermoplastic synthetic fibers made of linear polymers such as polyester and polyamide to produce fibers with increased strength.

An object of the present invention is to enable high-strength stretching of thermoplastic synthetic fibers made of linear polymers such as polyester and polyamide, thereby providing high-strength yarns.

When stretching a thermoplastic synthetic fiber made of a stretchable linear polymer, it is necessary to confine the stretching band that causes the stretching to a certain area to prevent non-uniform stretching.

For fibers that have the property of causing so-called necking, it is important to prevent the stretch belt from moving in order to prevent denier unevenness.

However, in general, when drawing at a high magnification, the stretch band is retracted from the heated part, and the stretch band is stretched, causing not only stretching irregularities but also frequent fiber breaks.

Therefore, various attempts have been made to confine the stretching zone to a specific area, such as by heating the stretching zone, but these methods have not produced sufficiently satisfactory results.

The present invention enables high-magnification stretching without yarn breakage by attaching an emulsion treatment oil containing a tetrafluoroethylene polymer to the surface of the fiber before stretching when thermoplastic synthetic fibers are stretched.

According to research conducted by the present inventors, when drawing synthetic twill made of linear polymers such as polyester and polyamide, slipping between fibers can be prevented by attaching an emulsion treatment oil containing a tetrafluoroethylene polymer to the fiber surface. It was found that it improves stretchability.

The tetrafluoroethylene polymer is preferably added in an equivalent weight of about 2% or more based on the weight of the oil agent.

When drawing synthetic fibers made of linear polymers such as polyester and polyamide, the drawing properties can be improved by spraying or impregnating the fibers with an oil agent containing fine powder of tetrafluoroethylene polymer.

Conventionally, stretching is performed after immersion in a general oil agent, but in the case of high-magnification stretching, friction between the fibers may cause the threads to break, or the stretching band may fluctuate, causing stretching unevenness. However, by incorporating tetrafluoroethylene polymer into the oil agent according to the present invention, the fibers can slip easily between each other, the stretching area is also fixed, and high-stretching is possible. It has become possible to produce high-strength woven fabrics. The present invention will be explained below with reference to Examples. Example Polycapramide for tire yarn 126 with a relative viscosity of 3.60 (polymer concentration in sulfuric acid: 1%) measured with sulfuric acid was melted into paper yarn at a paper yarn temperature of 305°C and a paper yarn speed of 450 m'min, and cooled and solidified. "The oil composition shown in Table 1, [A
] and a comparative oil composition [B], a 24% emulsion was applied to an undrawn yarn with a fat content of 1. As shown in the table, several stretching ratios were used to determine the maximum stretching ratio.

As shown in the table, the oil composition [A] containing the tetrafluoroethylene polymer has a higher maximum stretch ratio than the comparative oil composition [B] and has greatly improved stretchability, making it suitable for use as a tire yarn with high strength. A preferred polyamide yarn was obtained. 〔table〕

Claims (1)

[Claims] 1. A method for producing synthetic fibers, which comprises applying an oil agent containing fine powder of tetrafluoroethylene polymer to the surface of the fibers and stretching the thermoplastic synthetic fibers.