Liquid crystal polyester resin composition, method for producing same and molded body of same

Patent metadata

Field	Value
Publication number	US-12371542-B2
Application number	US-202017633406-A
Country	US
Kind code	B2
Filing date	Aug 4, 2020
Priority date	Aug 9, 2019
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

The present invention relates to: a liquid crystal polyester resin composition which contains a liquid crystal polyester resin and carbon fibers with a sizing agent; and a method for producing this liquid crystal polyester resin composition. The content of the carbon fibers with a sizing-agent is from 5 parts by mass to 120 parts by mass relative to 100 parts by mass of the liquid crystal polyester resin. With respect to the carbon fibers with a sizing-agent, the adhesion amount of the sizing agent with respect to the carbon fibers is from 0.1 parts by mass to 1.2 parts by mass relative to 100 parts by mass of the carbon fibers. If the carbon fibers with a sizing agent are heated from 25° C. to 400° C. in the air at a heating rate of 50° C./min, the mass loss rate within the range from 300° C. to 400° C. is less than 0.8% by mass.

First claim

The invention claimed is:

1. A liquid crystal polyester resin composition, comprising:
a liquid crystal polyester resin; and
sizing-agent-coated carbon fibers, wherein
an amount of the sizing-agent-coated carbon fibers relative to 100 parts by mass of the liquid crystal polyester resin is 5 parts by mass to 120 parts by mass,
an adhesion amount of a sizing agent to carbon fibers in the sizing-agent-coated carbon fibers relative to 100 parts by mass of the carbon fibers is 0.1 parts by mass to 1.2 parts by mass,
the liquid crystal polyester resin composition is a pellet in which the sizing-agent-coated carbon fibers are hardened with the liquid crystal polyester resin,
the carbon fibers are arranged to be parallel to a longitudinal direction of the pellet and have a length identical to a length of the pellet, and
when the sizing-agent-coated carbon fibers are heated in air from 25° C. to 400° C. at a temperature-increase rate of 50° C./min, a mass loss rate of the sizing-agent-coated carbon fibers within a range of 300° C. to 400° C. is less than 0.8% by mass, the mass loss rate being determined by an equation:
the mass loss rate(% by mass)=( W 300 −W 400 )/ W 300 ×100

wherein W 300 is a mass of the sizing-agent-coated carbon fibers measured at 300° C. and W 400 is a mass of the sizing-agent-coated carbon fibers measured at 400° C.

2. The liquid crystal polyester resin composition according to claim 1 , wherein an incipient fluidization temperature of the liquid crystal polyester resin is 280° C. or more.

3. The liquid crystal polyester resin composition according to claim 1 , wherein the length of the pellet is 3 mm to 50 mm.

4. A molded body prepared using a liquid crystal polyester resin composition of claim 1 .

5. A preparation method of a liquid crystal polyester resin composition, comprising mixing a liquid crystal polyester resin and sizing-agent-coated carbon fibers, wherein
a formulation amount of the sizing-agent-coated carbon fibers relative to 100 parts by mass of the liquid crystal polyester resin is 5 parts by mass to 120 parts by mass,
an adhesion amount of a sizing agent to carbon fibers in the sizing-agent-coated carbon fibers relative to 100 parts by mass of the carbon fibers is 0.1 parts by mass to 1.2 parts by mass, and
when the sizing-agent-coated carbon fibers are heated in air from 25° C. to 400° C. at a temperature-increase rate of 50° C./min, a mass loss rate of the sizing-agent-coated carbon fibers within a range of 300° C. to 400° C. is less than 0.8% by mass, the mass loss rate being determined by an equation:
the mass loss rate(% by mass)=( W 300 −W 400 )/ W 300 ×100

wherein W 300 is a mass of the sizing-agent-coated carbon fibers measured at 300° C. and W 400 is a mass of the sizing-agent-coated carbon fibers measured at 400° C.

6. The preparation method of a liquid crystal polyester resin composition according to claim 5 , wherein the preparation method is a method of obtaining a pellet in which the sizing-agent-coated carbon fibers are hardened with the liquid crystal polyester resin, and comprises:
obtaining a resin structure in which carbon fibers are arranged to be parallel to a longitudinal direction of a liquid crystal polyester resin layer, by immersing a carbon fiber bundle in which a plurality of single fibers is sized with a sizing agent with the liquid crystal polyester resin while reeling out the carbon fiber bundle, and
obtaining the pellet having a length identical to a length of the carbon fibers arranged in the liquid crystal polyester resin layer by cutting the resin structure to a predetermined length in a longitudinal direction thereof.

Assignees

• Sumitomo Chemical Co

Inventors

• Sugiyama Takayuki
• TAMURA Tasuku

Classifications

• C08J2367/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) · CPC title

• C08J5/243

  using carbon fibres · CPC title

• C08J2367/03

  the dicarboxylic acids and dihydroxy compounds having the hydroxy and the carboxyl groups directly linked to aromatic rings · CPC title

• C08J5/06

  using pretreated fibrous materials · CPC title

• C08G63/605

  the hydroxy and carboxylic groups being bound to aromatic rings · CPC title