Flat fiber-reinforced plastic strand, flat fiber-reinforced plastic strand sheet, and method of manufacturing the same

Abstract

Provided is a flat fiber-reinforced plastic strand which is produced by curing a twisted resin-impregnated strand and has no disturbed fiber orientation, and a flat fiber-reinforced plastic strand sheet which is produced by using said flat fiber-reinforced plastic strands. According to a method of manufacturing the flat fiber-reinforced plastic strand 2, (a) a twisted resin-impregnated strand f2 in an uncured state, the strand including a plurality of reinforcing fibers f, is fed in a state of tension between a pair of heated steel belts 41A and 41B facing each other and making rotation movements; and (b) the resin-impregnated strand f2 is sandwiched and heated by the steel belts 41A and 41B, and pressurized from both sides of the strand f2 to form a cross section of the strand into a flat shape, and, with the shape being kept, a resin is cured and cooled.

1 .- 14 . (canceled) 
     
     
         15 . A method of manufacturing a flat fiber-reinforced plastic strand sheet, the method comprising:
 (a) arranging a plurality of twisted resin-impregnated strands in an uncured state, the strands each including a plurality of reinforcing fibers, in one direction along a longitudinal direction of the strands in a planar fashion, and feeding said strands in a state of tension between a pair of heated steel belts facing each other and making rotation movements;   (b) sandwiching and heating the resin-impregnated strands by the steel belts, and pressurizing the resin-impregnated strands from both sides of the strands to form a cross section of the strands into a flat shape, and, with the shape being kept, curing and cooling a resin to produce a plurality of flat fiber-reinforced plastic strands; and   (c) subsequently, uniting and maintaining the plurality of flat fiber-reinforced plastic strands arranged in a planar fashion by a fixing material, thereby forming a sheet.   
     
     
         16 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 15 , wherein the number of twists of the resin-impregnated strand is from 5 twists/m to 30 twists/m. 
     
     
         17 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 15 , wherein the resin-impregnated strand is tensioned with a force of 500 g/piece to 10 kg/piece. 
     
     
         18 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 15 , wherein a release agent is continuously or periodically applied to the steel belts which make rotation movements, and the steel belts are further heated to bake said release agent thereonto. 
     
     
         19 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 18 , wherein a surface of the flat fiber-reinforced plastic strand produced in the step (b) is ground or washed with a solvent to remove a release agent which adheres to the surface, and then, the step (c) is performed. 
     
     
         20 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 15 , wherein, between the flat fiber-reinforced plastic strands arranged in a planar fashion in the step (c), a prescribed gap (g) is formed along a longitudinal direction of the strands. 
     
     
         21 . The method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 20 , wherein the prescribed gap (g) is from 0.1 mm to 3.0 mm. 
     
     
         22 . A flat fiber-reinforced plastic strand having a cross section in a flat shape and a thickness(t) of 0.2 to 5.0 mm and a width (w) of 1.0 to 10.0 mm, the fiber-reinforced plastic strand being manufactured by steps (a) and (b) of the method of manufacturing according to  claim 15 . 
     
     
         23 . A flat fiber-reinforced plastic strand sheet that is obtained by uniting and maintaining flat fiber-reinforced plastic strands arranged in a planar fashion by a fixing material to form a sheet,
 wherein the fiber-reinforced plastic strand sheet is manufactured by the method of manufacturing the flat fiber-reinforced plastic strand sheet according to  claim 15 , and   the flat fiber-reinforced plastic strand has a thickness (t) of 0.2 to 5.0 mm and a width (w) of 1.0 to 10.0 mm.