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Preparation method of wholly aromatic liquid crystal polyester nascent fibers

A liquid crystal polyester and primary fiber technology, which is applied in the field of fiber manufacturing materials and fibers, can solve problems such as uneven thickness, high equipment and cost requirements, and restrictions on the scale production of liquid crystal polyester spinning

Inactive Publication Date: 2020-05-12
SHANGHAI PRET CHEM NEW MATERIALS CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This is because there have been two key issues limiting the scale production of liquid crystal polyester spinning
First, the melt will be stretched to a certain extent during the spinning process, and usually the melt viscosity of the liquid crystal polyester is too low above the melting point, which leads to frequent broken bars, uneven thickness, and stretching ratio during the spinning process. Low-level phenomenon makes continuous and stable spinning more difficult; second, the strength of the primary fiber is not high. If you want to achieve the strength comparable to that of para-aramid, you need to carry out long-term post-treatment under high-temperature nitrogen. High cost requirements, low efficiency and small output

Method used

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  • Preparation method of wholly aromatic liquid crystal polyester nascent fibers
  • Preparation method of wholly aromatic liquid crystal polyester nascent fibers
  • Preparation method of wholly aromatic liquid crystal polyester nascent fibers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] Using LCP-1 resin as a raw material, use a drum to vacuumize the LCP-1 resin particles for 6 hours under the conditions of 200°C and a vacuum degree of 30P.

[0068] After vacuum treatment, the gas content of the resin particles was measured using a gas chromatograph.

[0069] The molten material was passed through a filter (made of stainless steel) using a multifilament spinning device of Jiangxi Huayuan Electromechanical Co., Ltd., and then discharged from a spinneret hole, and melt-spun at Tm+10°C. The spinneret hole diameter was 0.2 mm and the number of holes was 22, and the spinning was carried out under conditions of a discharge rate of 25 g / min and a spinning speed of 400 m / min.

Embodiment 2、3、4 and comparative example 1 to 2

[0071] Resin particles were treated in the same manner as in Example 1, except that the kind of resin, the temperature and time of vacuuming were changed as shown in Table 1. Using the obtained pellets, spinning was carried out in the same manner as in Example 1. Table 1 shows the evaluation results of crystallization melting temperature, melt viscosity, melt viscosity ratio and spinning condition of the wholly aromatic liquid crystal polyester resin.

[0072] Table 1

[0073]

[0074] As a result of the evaluation, it was found that after the post-treatment, the content of small molecules contained in the particles decreased significantly, so when spinning at a temperature of Tm+10°C, the as-spun yarns of the examples had higher tensile strength than those of the comparative examples.

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Abstract

The invention discloses a preparation method of wholly aromatic liquid crystal polyester nascent fibers. The preparation method is characterized by comprising the following step of vacuumizing or nitrogen purging particles, slices or powder of a liquid crystal polyester resin at 180-240 DEG C, wherein the content of micromolecules is lower than 50 ppm. The liquid crystal polyester (LCP) resin hasa melting point of 260-350 DEG C and has a P1 / P3 ratio greater than or equal to 3.0. P1, P2 and P3 are separately melt viscosities at a crystal melting temperature (Tm), a temperature of Tm+10 DEG C and a temperature of Tm+20 DEG C on a rheological tester, the pore diameter of a nozzle of which is 0.5 mm, under a circumstance that the shearing rate is 1000 / s. The melt viscosity range of P3 is 20-50 Pa.S. As a result of extremely low content of micromolecules, the treated liquid crystal polyester resin is better in continuity, is unlikely to break and uniform in fiber thickness if being spun ina temperature range from Tm to Tm+10 DEG C. A prepared spun filament is higher in strength and can reach breaking strength of 7-10 cN / dtex.

Description

technical field [0001] The invention relates to materials and fibers for fiber manufacturing. The wholly aromatic liquid crystal polyester resin of the invention has better continuity during spinning, is not easy to break, and has uniform fiber thickness. Background technique [0002] Liquid crystal polyester fiber has been widely concerned by people because of its excellent low hygroscopicity, heat resistance and high mechanical strength. In the 1980s, Celanese Corporation of the United States prepared spinning-grade liquid crystal polyester resin using two monomers, p-hydroxybenzoic acid and dihydroxyhexanaphthoic acid, and realized the industrial production of liquid crystal polyester fibers. Sold to Japan Kuraray Corporation. In recent years, Japan's Toray Corporation melted and polymerized a small amount of PET and aromatic monomers to prepare a new type of semi-aromatic and semi-aliphatic liquid crystal polyester resin, and also successfully prepared liquid crystal po...

Claims

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Application Information

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IPC IPC(8): D01F6/84C08G63/60C08G63/90
CPCD01F6/84C08G63/605C08G63/90C08G2250/00
Inventor 魏伟李宏周文
Owner SHANGHAI PRET CHEM NEW MATERIALS CO LTD
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