Method of manufacturing fiber-reinforced thermoplastic resin of cellular structure

Claim 1

A method of manufacturing a fiber-reinforced thermoplastic resin of cellular structure which comprises the steps of: immersing a roving of filaments of glass fibrous reinforcing material in a bath containing an emulsion of thermoplastic resin containing a blowing agent, said emulsion having a minimum film forming temperature of not less than 50° C.; collecting a plurality of the emulsion-impregnated rovings together to provide a bunch of rovings; squeezing out the excess emulsion and drying the bunch of rovings to obtain a resultant product containing glass fibers in an amount of about 30% by weight relative to the total weight of the dried rovings; preheating the dried bunch of rovings at a temperature in which the thermoplastic resin is softened but the blowing agent does not decompose; compressing the preheated bunch of rovings within a press bed under heated conditions having the same temperature as that of said preheating step to provide an integrally bonded block of the fiber-reinforced thermoplastic resin in such a manner that the thermoplastic resin particles impregnated in the immersing step and subsequently dried are integrally bonded together with interstices among glass fibers diminished, by applying a pressure at a temperature lower than the temperature of decomposition of the blowing agent; allowing the integrally bonded block of fiber-reinforced thermoplastic resin to expand within a mold under heated condition at a temperature higher than the temperature at which the thermoplastic resin employed can be fused and, also, at which the blowing agent employed undergoes decomposition, thereby providing a fiber-reinforced thermoplastic resin of cellular structure the amount of glass fiber contained therein being within the range of 20 to 50% relative to the total weight of the final product; and cooling the fiber-reinforced thermoplastic resin of cellular structure to ambient temperature.

Claim 2

A method of manufacturing a fiber-reinforced thermoplastic resin of cellular structure which comprises the steps of: immersing a roving of filaments of glass fibrous reinforcing material in a bath containing an emulsion of thermoplastic resin containing a blowing agent, said emulsion having a minimum film forming temperature of not less than 50° C.; collecting a plurality of the emulsion-impregnated rovings together to provide a bunch of rovings; squeezing out the excess emulsion and drying the bunch of rovings to obtain a resultant product containing glass fibers in an amount of about 30% by weight relative to the total weight of the dried rovings; preheating the dried bunch of rovings at a temperature in which the thermoplastic resin is softened but the blowing agent does not decompose; compressing the preheated bunch of rovings within a press bed under heated conditions having the same temperature as that of said preheating step to provide an integrally bonded block of the fiber-reinforced thermoplastic resin in such a manner that the thermoplastic resin particles impregnated in the immersing step and subsequently dried are integrally bonded together with interstices among glass fibers diminished, by applying a pressure at a temperature lower than the temperature of decomposition of the blowing agent; allowing the integrally bonded block of fiber-reinforced thermoplastic resin to expand within a mold under heated condition at a temperature higher than the temperature at which the thermoplastic resin employed can be fused and, also, at which the blowing agent employed undergoes decomposition, thereby providing a fiber-reinforced thermoplastic resin of cellular structure the amount of glass fiber contained therein being within the range of 20 to 50% relative to the total weight of the final product; and cooling the fiber-reinforced thermoplastic resin of cellular structure to ambient temperature.

Claim 6

A method of manufacturing a fiber-reinforced thermoplastic resin of cellular structure which comprises the steps of: immersing a roving of glass filaments of fibrous reinforcing material in a bath containing an emulsion of thermoplastic resin containing a blowing agent, said emulsion having a minimum film forming temperature of not less than 50° C.; squeezing out the excess emulsion and drying the emulsion-impregnated rovings to obtain a resultant product containing glass fibers in an amount of about 30% by weight relative to the total weight of the dried rovings; collecting a plurality of the dried rovings together to provide a bunch of rovings; preheating the dried bunch of rovings at a temperature in which the thermoplastic resin is softened but the blowing agent does not decompose; compressing the preheated bunch of rovings within a press bed under heated conditions having the same temperature as that of said preheating step to provide an integrally bonded block of the fiber-reinforced thermoplastic resin in such a manner that the thermoplastic resin particles impregnated in the immersing step and subsequently dried are integrally bonded together with interstices among glass fibers diminished, by applying a pressure at a temperature lower than the temperature of decomposition of the blowing agent; allowing the integrally bonded block of fiber-reinforced thermoplastic resin to expand within a mold under heated condition at a temperature higher than the temperature at which the thermoplastic resin employed can be fused and, also, at which the blowing agent employed undergoes decomposition, thereby providing the fiber-reinforced thermoplastic resin of cellular structure the amount of glass fiber contained therein being within the range of 20 to 50% relative to the total weight of the final product; and cooling the fiber-reinforced thermoplastic resin of cellular structure to the ambient temperature.

Claim 7

A method of manufacturing a fiber-reinforced thermoplastic resin of cellular structure which comprises the steps of: immersing a roving of glass filaments of fibrous reinforcing material in a bath containing an emulsion of thermoplastic resin containing a blowing agent, said emulsion having a minimum film forming temperature of not less than 50° C.; squeezing out the excess emulsion and drying the emulsion-impregnated rovings to obtain a resultant product containing glass fibers in an amount of about 30% by weight relative to the total weight of the dried rovings; collecting a plurality of the dried rovings together to provide a bunch of rovings; preheating the dried bunch of rovings at a temperature in which the thermoplastic resin is softened but the blowing agent does not decompose; compressing the preheated bunch of rovings within a press bed under heated conditions having the same temperature as that of said preheating step to provide an integrally bonded block of the fiber-reinforced thermoplastic resin in such a manner that the thermoplastic resin particles impregnated in the immersing step and subsequently dried are integrally bonded together with interstices among glass fibers diminished, by applying a pressure at a temperature lower than the temperature of decomposition of the blowing agent; allowing the integrally bonded block of fiber-reinforced thermoplastic resin to expand within a mold under heated condition at a temperature higher than the temperature at which the thermoplastic resin employed can be fused and, also, at which the blowing agent employed undergoes decomposition, thereby providing the fiber-reinforced thermoplastic resin of cellular structure the amount of glass fiber contained therein being within the range of 20 to 50% relative to the total weight of the final product; and cooling the fiber-reinforced thermoplastic resin of cellular structure to the ambient temperature.