Amorphous heat-fusible fiber, fiber structure, and heat-resistant molded article

Abstract

Provided are a heat-fusible fiber having excellent heat resistance, flame retardancy and dimensional stability; a fiber structure comprising the heat-fusible fiber; and a molded article produced by applying a heat fusion treatment to the fiber structure and having excellent heat resistance. The heat-fusible fiber comprises an amorphous PES type polymer (A) not substantially having a melting point and an amorphous PEI type polymer (B) in the mixture ratio (weight) of (A)/(B)=5/95 to 95/5, the fiber having a single glass transition temperature in the range between 80° C. and 200° C., and being amorphous. The fiber structure comprises 10% by weight or higher of the amorphous heat-fusible fiber. The molded article comprises at least a fiber structure comprising 10% by weight or higher of the amorphous heat-fusible fiber, to be fusion-bonded at a temperature higher than the glass transition temperature of the amorphous heat-fusible fiber.

1 : An amorphous heat-fusible fiber, comprising:
 (A) an amorphous polyester not substantially having a melting point; and   (B) an amorphous polyetherimide,   wherein:   a weight ratio of (A)/(B) is 5/95 to 95/5; and   the fiber has a single glass transition temperature in a range between 80° C. and 200° C.   
     
     
         2 : The amorphous heat-fusible fiber of  claim 1 , wherein the amorphous polyester (A) comprises a terephthalic acid component (D) and an isophthalic acid component (E), wherein a copolymerization ratio (mole % ratio) of (D)/(E) ranges from 70/30 to 40/60. 
     
     
         3 : The amorphous heat-fusible fiber of  claim 1 , wherein:
 the amorphous polyetherimide (B) has a glass transition temperature of 210° C. or higher and comprises a main repeating structure unit represented by the following formula:   
       
         
           
           
               
               
           
         
         R1 represents a divalent aromatic residue having 6 to 30 carbon atoms; and 
         R2 represents a divalent organic group selected from the group consisting of a divalent aromatic residue having 6 to 30 carbon atoms, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 2 to 20 carbon atoms, and a polydiorganosiloxane group in which the chain is terminated by an alkylene group having 2 to 8 carbon atoms. 
       
     
     
         4 : The amorphous heat-fusible fiber of  claim 1 , having a dry heat shrinkage percentage of 3% or less at a temperature of (glass transition temperature −10) ° C. 
     
     
         5 : The amorphous heat-fusible fiber of  claim 1 , wherein the fiber is a melt-spun and un-drawn fiber. 
     
     
         6 : A fiber structure, comprising 10% by weight or higher of the amorphous heat-fusible fiber of  claim 1 . 
     
     
         7 : A heat-resistant molded article, comprising a fiber structure, comprising 10% by weight or higher of the amorphous heat-fusible fiber of  claim 1 , said fiber structure being fusion-bonded at a temperature higher than the glass transition temperature of the amorphous heat-fusible fiber. 
     
     
         8 : The amorphous heat-fusible fiber of  claim 1 , wherein the amorphous polyester (A) consists of a terephthalic acid component (D) and an isophthalic acid component (E), wherein a copolymerization ratio (mole % ratio) of (D)/(E) ranges from 70/30 to 40/60. 
     
     
         9 : The amorphous heat-fusible fiber of  claim 2 , wherein:
 the amorphous polyetherimide (B) has a glass transition temperature of 210° C. or higher and comprises a main repeating structure unit represented by the following formula:   
       
         
           
           
               
               
           
         
         R1 represents a divalent aromatic residue having 6 to 30 carbon atoms; and 
         R2 represents a divalent organic group selected from the group consisting of a divalent aromatic residue having 6 to 30 carbon atoms, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 2 to 20 carbon atoms, and a polydiorganosiloxane group in which the chain is terminated by an alkylene group having 2 to 8 carbon atoms. 
       
     
     
         10 : The amorphous heat-fusible fiber of  claim 2 , having a dry heat shrinkage percentage of 3% or less at a temperature of (glass transition temperature −10) ° C. 
     
     
         11 : The amorphous heat-fusible fiber of  claim 2 , wherein the fiber is a melt-spun and un-drawn fiber. 
     
     
         12 : A fiber structure, comprising 10% by weight or higher of the amorphous heat-fusible fiber of  claim 2 . 
     
     
         13 : A heat-resistant molded article, comprising a fiber structure comprising 10% by weight or higher of the amorphous heat-fusible fiber of  claim 2 , said fiber structure being fusion-bonded at a temperature higher than the glass transition temperature of the amorphous heat-fusible fiber.