Foam-molded product, method for manufacturing foam-molded product, and method for suppressing appearance defect of foam-molded product
A foam-molded product including a foam layer, and a skin layer covering the foam layer, in which the maximum diameter of bubbles in the foam layer is 0.90 mm or less; and a method for manufacturing a foam-molded product and a method for suppressing an appearance defect of a foam-molded product, including an injection process and a foaming process, wherein the foam-molded product after molding includes a foam layer and a skin layer covering the foam layer, the skin layer having an average thickness of from 0.3 mm to 0.7 mm, and wherein expanding of the volume of the cavity includes performing a core-back process of the mold such that a thickness of the foam-molded product after molding is within ±0.2 mm of a predetermined target thickness.
1 . An automobile interior or exterior part comprising a foam-molded product, the foam-molded product comprising a foam layer, which comprises bubbles, and a skin layer covering the foam layer, wherein:
the foam-molded product is a molded product of a resin material comprising at least one selected from the group consisting of a polypropylene resin having a branched chain and a melt flow rate of 35 g/10 minutes or more at 230° C., and an acrylonitrile-butadiene-styrene copolymer resin (ABS),
the foam layer and the skin layer are made of the same material,
a maximum diameter of the bubbles in the foam layer is from 0.05 to 0.20 mm,
an average diameter of the bubbles in the foam layer is from 0.02 mm to 0.15 mm, and
the skin layer has an average thickness of from 0.3 mm to 0.7 mm.
2 . The automobile interior or exterior part according to claim 1 , wherein the automobile interior or exterior part is an automobile exterior part.
3 . The automobile interior or exterior part according to claim 1 , wherein the automobile interior or exterior part is not painted on a surface thereof.
4 . The automobile interior or exterior part according to claim 1 , wherein the automobile interior or exterior part is at least one selected from the group consisting of a console box, a door trim, a deck side trim, a back door trim, an instrument panel, an arch molding, a rocker molding, and a side panel.
5 . The automobile interior or exterior part according to claim 1 , wherein a content of the polypropylene resin having a branched chain is 4% by mass or more with respect to the total amount of the resin material.
6 . The automobile interior or exterior part according to claim 1 , wherein the resin material further comprises an organic foaming agent.
7 . The automobile interior or exterior part according to claim 6 , wherein the organic foaming agent is azodicarbonamide.
8 . The automobile interior or exterior part according to claim 1 , wherein:
the average diameter of the bubbles in the foam layer is from 0.02 mm to 0.10 mm;
the maximum diameter of the bubbles in the foam layer is from 0.10 mm to 0.20 mm; and
the foam layer has an average thickness of from 1.0 mm to 4.0 mm.
9 . A method for manufacturing an automobile interior or exterior part comprising a foam-molded product, the method comprising:
injecting a resin material into a cavity of a mold to fill the cavity with the resin material; and
expanding a volume of the cavity to foam the resin material in the cavity to form the foam-molded product of the automobile interior or exterior part, wherein:
the foam-molded product is a molded product of the resin material comprising at least one selected from the group consisting of a polypropylene resin having a branched chain and a melt flow rate of 35 g/10 minutes or more at 230° C., and an acrylonitrile-butadiene-styrene copolymer resin (ABS),
the foam-molded product after molding comprises a foam layer, which comprises bubbles, and a skin layer covering the foam layer, the skin layer has an average thickness of from 0.3 mm to 0.7 mm, and an average diameter of bubbles in the foam layer is from 0.02 mm to 0.15 mm,
the foam layer and the skin layer are made of the same material, and
the expanding of the volume of the cavity comprises performing a core-back process of the mold such that a thickness of the foam-molded product after molding is within +0.2 mm of a predetermined target thickness, as a result of which a maximum diameter of the bubbles in the foam-molded product is from 0.05 to 0.20 mm.
10 . A method for suppressing an appearance defect of an automobile interior or exterior part comprising a foam-molded product, the method comprising:
injecting a resin material into a cavity of a mold to fill the cavity with the resin material; and
expanding a volume of the cavity to foam the resin material in the cavity to form the foam-molded product of the automobile interior or exterior part, wherein:
the foam-molded product is a molded product of the resin material comprising at least one selected from the group consisting of a polypropylene resin having a branched chain and a melt flow rate of 35 g/10 minutes or more at 230° C., and an acrylonitrile-butadiene-styrene copolymer resin (ABS),
the foam-molded product after molding comprises a foam layer, which comprises bubbles, and a skin layer covering the foam layer, the skin layer has an average thickness of from 0.3 mm to 0.7 mm, and an average diameter of bubbles in the foam layer is from 0.02 mm to 0.15 mm,
the foam layer and the skin layer are made of the same material, and
the expanding of the volume of the cavity comprises performing a core-back process of the mold such that a thickness of the foam-molded product after molding is within ±0.2 mm of a predetermined target thickness, as a result of which a maximum diameter of the bubbles in the foam-molded product is from 0.05 to 0.20 mm.