Reinforced thermoplastic-resin multilayer sheet material, process for producing the same, and method of forming molded thermoplastic-resin composite material

Abstract

The present invention provides a high-quality multilayer thermoplastic-resin-reinforced sheet material having excellent mechanical properties and drapeability in which a thermoplastic resin excellent in recycling efficiency and shock resistance is used as a matrix; a method for efficiently producing the multilayer thermoplastic-resin-reinforced sheet material in a short time; and a thermoplastic-resin multilayer reinforced molding formed of the multilayer thermoplastic-resin-reinforced sheet material, in which the high quality and the mechanical properties are maintained. A multilayer thermoplastic-resin-reinforced sheet material ( 11 ) is formed by stacking thermoplastic-resin-reinforced sheet materials ( 21 A) to ( 21 D) each formed of a reinforcing-fiber sheet material ( 31 ), consisting of a plurality of reinforcing fibers ( 31 f ) arranged in a predetermined direction in a sheet-like structure, and a thermoplastic-resin sheet material ( 41 ) joined to a surface of the reinforcing-fiber sheet material ( 31 ), and stitching them together with an integration thermoplastic-resin fiber tow ( 51 ) composed of the same material as the thermoplastic-resin sheet material ( 41 ). The reinforcing-fiber sheet materials ( 31 ) are stacked such that their reinforcing directions are multiaxial.

1 . A multilayer thermoplastic-resin-reinforced sheet material formed by stacking and integrating a plurality of thermoplastic-resin-reinforced sheet materials each formed of a reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a thermoplastic-resin sheet material that are joined together. 
     
     
         2 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein, in each of the thermoplastic-resin-reinforced sheet materials, one of the thermoplastic-resin sheet material and the reinforcing-fiber sheet material is joined to each surface of the other sheet material.   
     
     
         3 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the thermoplastic-resin-reinforced sheet materials are each formed of a plurality of narrow thermoplastic-resin-reinforced sheet materials arranged in a width direction, the plurality of narrow thermoplastic-resin-reinforced sheet materials each formed of a narrow reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a narrow thermoplastic-resin sheet material that are joined together.   
     
     
         4 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the thermoplastic-resin-reinforced sheet materials are each formed by weaving a narrow thermoplastic-resin-reinforced sheet material formed of a narrow reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a narrow thermoplastic-resin sheet material that are joined together.   
     
     
         5 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the thermoplastic-resin-reinforced sheet materials are stacked such that arrangement directions of the reinforcing-fiber sheet materials are multiaxial.   
     
     
         6 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the cross-sectional thickness of each reinforcing-fiber sheet material is set within ten times the diameter of each reinforcing fiber.   
     
     
         7 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the plurality of stacked thermoplastic-resin-reinforced sheet materials are stitched together with an integration thermoplastic-resin fiber tow composed of the same material as the thermoplastic-resin sheet materials.   
     
     
         8 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the plurality of stacked thermoplastic-resin-reinforced sheet materials are bonded together by thermal adhesion of the thermoplastic-resin sheet materials.   
     
     
         9 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 8 ,
 wherein the plurality of stacked thermoplastic-resin-reinforced sheet materials are bonded together by partial thermal adhesion of the thermoplastic-resin sheet materials.   
     
     
         10 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 1 ,
 wherein the thermoplastic-resin-reinforced sheet materials each have a bonding thermoplastic-resin material that is melted or softened at a temperature lower than the melting temperature of the thermoplastic-resin sheet material and deposited on one or both surfaces of at least one of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material.   
     
     
         11 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 10 ,
 wherein the thermoplastic-resin-reinforced sheet materials are each formed of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material that are bonded together with the bonding thermoplastic-resin material.   
     
     
         12 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 11 , the thermoplastic-resin-reinforced sheet materials each being formed of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material that are bonded together with the bonding thermoplastic-resin material, the bonding thermoplastic-resin material being deposited on one or both surfaces of each thermoplastic-resin-reinforced sheet material,
 wherein the amount of deposition per unit area of the bonding thermoplastic-resin material for bonding the reinforcing-fiber sheet material and the thermoplastic-resin sheet material is different from the amount of deposition per unit area of the bonding thermoplastic-resin material deposited on one or both surfaces of each thermoplastic-resin-reinforced sheet material.   
     
     
         13 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 11 , the thermoplastic-resin-reinforced sheet materials each being formed of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material that are bonded together with the bonding thermoplastic-resin material, the bonding thermoplastic-resin material being deposited on one or both surfaces of each thermoplastic-resin-reinforced sheet material,
 wherein the bonding thermoplastic-resin material for bonding the reinforcing-fiber sheet material and the thermoplastic-resin sheet material is a resin different from the bonding thermoplastic-resin material deposited on one or both surfaces of each thermoplastic-resin-reinforced sheet material.   
     
     
         14 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 10 ,
 wherein the amount of deposition per unit area of the bonding thermoplastic-resin material is within 3% of the weight per unit area of the reinforcing-fiber sheet material.   
     
     
         15 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 10 ,
 wherein the plurality of stacked thermoplastic-resin-reinforced sheet materials are bonded together by heat-melting or heat-softening the bonding thermoplastic-resin material.   
     
     
         16 . The multilayer thermoplastic-resin-reinforced sheet material according to  claim 15 ,
 wherein the plurality of stacked thermoplastic-resin-reinforced sheet materials are partially bonded together by partially heat-melting or heat-softening the bonding thermoplastic-resin material.   
     
     
         17 . A method for producing a multilayer thermoplastic-resin-reinforced sheet material, the method comprising:
 a sheet forming step for forming a thermoplastic-resin-reinforced sheet material by joining a reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a thermoplastic-resin sheet material,   a stacking step for stacking a plurality of the thermoplastic-resin-reinforced sheet materials in a thickness direction, and   an integration step for integrating the plurality of stacked thermoplastic-resin-reinforced sheet materials.   
     
     
         18 . The method for producing the multilayer thermoplastic-resin-reinforced sheet material according to  claim 17 ,
 wherein, in the sheet forming step, one of the thermoplastic-resin sheet material and the reinforcing-fiber sheet material is joined to each surface of the other sheet material.   
     
     
         19 . The production method according to  claim 17 ,
 wherein, in the sheet forming step, a narrow thermoplastic-resin-reinforced sheet material is formed by joining a narrow reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a narrow thermoplastic-resin sheet material, and a plurality of the narrow thermoplastic-resin-reinforced sheet materials are arranged in a width direction to form the thermoplastic-resin-reinforced sheet material.   
     
     
         20 . The production method according to  claim 17 ,
 wherein, in the sheet forming step, a narrow thermoplastic-resin-reinforced sheet material is formed by joining a narrow reinforcing-fiber sheet material, consisting of a plurality of reinforcing fibers arranged in a predetermined direction, and a narrow thermoplastic-resin sheet material, the narrow thermoplastic-resin-reinforced sheet material is woven into the thermoplastic-resin-reinforced sheet material.   
     
     
         21 . The production method according to  claim 19 ,
 wherein, in the method for forming the narrow thermoplastic-resin-reinforced sheet material in the sheet forming step, after the thermoplastic-resin-reinforced sheet material is formed by joining the reinforcing-fiber sheet material, consisting of the plurality of reinforcing fibers arranged in a predetermined direction, and the thermoplastic-resin sheet material, the thermoplastic-resin-reinforced sheet material is cut in a length direction, at a desired interval in a width direction, to form the plurality of narrow thermoplastic-resin-reinforced sheet materials.   
     
     
         22 . The production method according to  claim 17 ,
 wherein, in the stacking step, a plurality of the thermoplastic-resin-reinforced sheet materials are stacked such that the arrangement directions of the reinforcing fibers are multiaxial.   
     
     
         23 . The production method according to  claim 17 ,
 wherein, in the sheet forming step, the reinforcing-fiber sheet material is formed into a sheet-like structure in which a plurality of reinforcing fibers are arranged in a predetermined direction, the cross-sectional thickness of the reinforcing-fiber sheet material being set within ten times the diameter of each reinforcing fiber.   
     
     
         24 . The production method according to  claim 17 ,
 wherein, in the sheet forming step, the reinforcing-fiber sheet material is formed from a wide and thin multi-filament spread thread formed by continuously spreading, in a width direction, a reinforcing fiber tow consisting of a plurality of filament-type reinforcing fibers bundled together.   
     
     
         25 . The production method according to  claim 17 ,
 wherein the sheet forming step includes a deposition step for depositing a bonding thermoplastic-resin material that is melted or softened at a temperature lower than the melting temperature of the thermoplastic-resin sheet material on one or both surfaces of the thermoplastic-resin-reinforced sheet material or the narrow thermoplastic-resin-reinforced sheet material.   
     
     
         26 . The production method according to  claim 17 ,
 wherein the sheet forming step includes a deposition step for depositing a bonding thermoplastic-resin material that is melted or softened at a temperature lower than the melting temperature of the thermoplastic-resin sheet material to one or both surfaces of at least one of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material, and a joining step for joining the reinforcing-fiber sheet material and the thermoplastic-resin sheet material by disposing one of the reinforcing-fiber sheet material and the thermoplastic-resin sheet material on one or both surfaces of the other sheet material with the bonding thermoplastic-resin material therebetween and by subjecting them to heat or heat and pressure at a temperature lower than the melting temperature of the thermoplastic-resin sheet material to melt or soften the bonding thermoplastic-resin material.   
     
     
         27 . The production method according to  claim 17 ,
 wherein, in the integration step, the plurality of stacked thermoplastic-resin-reinforced sheet materials are stitched together with an integration thermoplastic-resin fiber tow composed of the same material as the thermoplastic-resin sheet materials.   
     
     
         28 . The production method according to  claim 17 ,
 wherein, in the integration step, the plurality of stacked thermoplastic-resin-reinforced sheet materials are bonded together by applying heat or heat and pressure to the plurality of stacked thermoplastic-resin-reinforced sheet materials to allow the thermoplastic-resin sheet materials in the respective layers to be thermally adhered to the reinforcing-fiber sheet materials in upper and lower layers in a thickness direction.   
     
     
         29 . The production method according to  claim 26 ,
 wherein, in the integration step, heat or heat and pressure is partially applied to the plurality of stacked thermoplastic-resin-reinforced sheet materials to allow the thermoplastic-resin sheet materials in the respective layers to be thermally adhered to the reinforcing-fiber sheet materials in upper and lower layers in a thickness direction.   
     
     
         30 . The production method according to  claim 25 ,
 wherein, in the integration step, heat or heat and pressure is applied to the plurality of stacked thermoplastic-resin-reinforced sheet materials at a temperature at which the bonding thermoplastic-resin material is melted or softened so as to bond the layers of the plurality of stacked thermoplastic-resin-reinforced sheet materials with the bonding thermoplastic-resin material.   
     
     
         31 . The production method according to  claim 30 ,
 wherein, in the integration step, heat or heat and pressure is partially applied to the plurality of stacked thermoplastic-resin-reinforced sheet materials at a temperature at which the bonding thermoplastic-resin material is melted or softened so as to partially bond the layers of the plurality of stacked thermoplastic-resin-reinforced sheet materials with the bonding thermoplastic-resin material.   
     
     
         32 . A thermoplastic-resin multilayer reinforced molding obtained by cutting a multilayer thermoplastic-resin-reinforced sheet material produced by the production method according to  claim 17  into pieces having a desired size, stacking a desired number of the pieces in a shaping mold at a desired angle, and performing hot press molding to allow the reinforcing-fiber sheet material to be impregnated with the thermoplastic-resin sheet material, and, in the case of stitch-integration, with the integration thermoplastic-resin fiber tow. 
     
     
         33 . A thermoplastic-resin multilayer reinforced molding obtained by cutting a multilayer thermoplastic-resin-reinforced sheet material produced by the production method according to  claim 17  into pieces having a desired size, stacking a desired number of the pieces in a preforming mold at a desired angle, performing hot press molding to allow the reinforcing-fiber sheet material to be impregnated with the thermoplastic-resin sheet material, and, in the case of stitch-integration, with the integration thermoplastic-resin fiber tow, to obtain a preformed laminate, heating the preformed laminate to make it deformable, placing it in a shaping mold, and performing press molding. 
     
     
         34 . A method for forming a thermoplastic-resin composite-material molding from a molding material composed of a reinforcing fiber material and a thermoplastic resin material, the method comprising: disposing the molding material between a pair of shaping molds formed to have a uniform thickness at contact portions with respect to the molding material; clamping the molding material between the shaping molds in a manner that inside gas can be discharged from the periphery of the molding material; placing the shaping molds clamping the molding material therebetween between a pair of hot press molds having contact surfaces formed to fit contact surfaces of the shaping molds; performing hot pressing; placing the shaping molds having gone through the hot pressing between a pair of cold press molds having contact surfaces formed to fit the contact surfaces of the shaping molds; and performing cold pressing to cure the thermoplastic resin material melted and impregnated into the layers. 
     
     
         35 . The forming method according to  claim 34 ,
 wherein the molding material is clamped such that a space into which gas inside the molding material is discharged is formed between the shaping molds, and the space into which the gas is discharged is brought into a vacuum or reduced pressure state.   
     
     
         36 . The forming method according to  claim 34 ,
 wherein a plurality of the shaping molds clamping the molding material are stacked and subjected to hot pressing and cold pressing.   
     
     
         37 . The forming method according to  claim 34 ,
 wherein hot pressing is sequentially performed using a plurality of hot press molds having different temperatures.   
     
     
         38 . The forming method according to  claim 34 ,
 wherein cold pressing is sequentially performed using a plurality of cold press molds having different temperatures.   
     
     
         39 . The forming method according to  claim 34 ,
 wherein the contact portions of the shaping molds are formed to be thin.   
     
     
         40 . The forming method according to  claim 34 ,
 wherein the shaping molds are composed of a carbon fiber carbon composite material.   
     
     
         41 . The forming method according to  claim 34 ,
 wherein the contact surfaces of the shaping molds to be in contact with the molding material are treated with a release treatment.   
     
     
         42 . The forming method according to  claim 34 ,
 wherein, in the molding material, the thermoplastic resin material serving as a matrix is unevenly distributed between layers of the reinforcing fiber materials.