Molded article of composite resin containing fibers

Abstract

A molded article of a composite resin containing fibers includes a base resin 1 and a fibrous filler 2 having fibrillated ends in a fiber length direction. An expression Ho×0.4≤H≤Ho is satisfied where H is a maximum height for an unbroken first plate-like test piece having a thickness of 1 to 2 mm after the test piece is kept at −10° C. for three hours and then is hit by a dropped weight of 250 g; and Ho is as same maximum height for the unbroken second plate-like test piece only made of the base resin with a thickness of 1 to 2 mm as for the first plate-like test piece. An expression So×0.4≤S≤So is satisfied where S is a Charpy impact strength (JIS K 7111) of the molded article, and So is a Charpy impact strength of the molded article only made of the base resin.

1 . A molded article of a composite resin containing fibers, the composite resin containing a fibrous filler in base resin,
 wherein the fibrous filler has a fibrillated part on each end of the fibrous filler in a fiber length direction,   the composite resin exhibits physical characteristics satisfying:
     Ho× 0.4≤ H≤Ho  
 
   where H is a maximum height when a first plate-like test piece is not broken when a weight of 250 g is dropped from a certain height after the first plate-like test piece is kept at −10° C. for three hours, the first plate-like test piece being made of the composite resin with a thickness of 1 to 2 mm; and Ho is a maximum height when a second plate-like test piece is not broken when a weight of 250 g is dropped from a certain height after the second plate-like test piece is kept at −10° C. for three hours, the second plate-like test piece being only made of the base resin with the same thickness as the first plate-like test piece, and
     So× 0.4≤ S≤So  
 
   where S is a Charpy impact strength specified in JIS K 7111 of the molded article of the composite resin, and So is a Charpy impact strength specified in JIS K 7111 of the molded article only made of the base resin.   
     
     
         2 . A molded article of a composite resin containing fibers, the composite resin containing a fibrous filler in base resin, wherein the fibrous filler has a non-fibrillated part that is not fibrillated and a fibrillated part on each end of the fibrous filler in a fiber length direction. 
     
     
         3 . The molded article of the composite resin containing fibers according to  claim 2 , wherein the fibrous filler has a median fiber diameter of 0.1 to 2 μm on the fibrillated part, and
 the fibrous filler has a median fiber diameter of 5 to 30 μm on the non-fibrillated part. 
 
     
     
         4 . The molded article of the composite resin containing fibers according to  claim 1 , wherein the fibrous filler is natural fibers of cellulose. 
     
     
         5 . The molded article of the composite resin containing fibers according to  claim 1 , wherein the base resin is an olefin resin. 
     
     
         6 . A molded article of a composite resin containing fibers, the composite resin containing a fibrous filler in base resin, wherein the fibrous filler has a non-fibrillated part that is not fibrillated at the center of the fiber in a fiber length direction and a fibrillated part on each end of the fibrous filler in the fiber length direction,
 the fibrous filler has a median fiber diameter of 0.1 to 2 μm on the fibrillated part and has a median fiber diameter of 5 to 30 μm on the non-fibrillated part,   the fibrillated part prevents cracking caused by connection of a plurality of crazing defects occurring when an impact force is applied to the molded article in a plane direction, and   the non-fibrillated part that is not fibrillated prevents cracking defects occurring when an impact force is applied to the molded article in one direction as in a Charpy impact test.