Foam molded product and method for producing the same
The present invention is to provide a thermoplastic polyester elastomer resin foam molded product which exhibits light weight, excellent rebound resilience and excellent surface smoothness. A foam molded product including a continuous phase formed of a resin component containing a thermoplastic polyester elastomer, wherein the thermoplastic polyester elastomer is prepared by bonding a hard segment and a soft segment, wherein the hard segment consists of polyester constituted from aromatic dicarboxylic acid and aliphatic and/or alicyclic diol as constituting components, wherein the soft segment is at least one member selected from a group consisting of aliphatic polyether, aliphatic polyester and aliphatic polycarbonate, wherein the foam molded product is constituted from, as a surface layer ranging from a surface of the foam molded product to a depth of 1000 μm, a surface layer consisting of only a foamed region in which a non-foamed portion having a cell density of 10% or less is not present, or the foam molded product has, as a surface layer ranging from a surface of the foam molded product to a depth of 1000 μm, a surface layer consisting of both a foamed region in which the non-foamed portion is present and a foamed region in which the non-foamed portion is not present, and wherein the foam molded product has a density of 0.01 to 0.70 g/cm 3 .
1. A foam molded product comprising a continuous phase formed of a resin component containing a thermoplastic polyester elastomer, wherein the thermoplastic polyester elastomer is prepared by bonding a hard segment and a soft segment, wherein the hard segment consists of polyester constituted from aromatic dicarboxylic acid and aliphatic and/or alicyclic diol as constituting components, wherein the soft segment is at least one member selected from the group consisting of aliphatic polyether, aliphatic polyester and aliphatic polycarbonate,
wherein
(a) the foam molded product is constituted from, a first surface layer consisting of only a foamed region in which a non-foamed portion having a cell density of 10% or less is not present, the first surface layer ranging from a surface of the foam molded product to a depth of 1000 μm, or
(b) the foam molded product has, a second surface layer consisting of both a foamed region in which the non-foamed portion is present and a foamed region in which the non-foamed portion is not present, the second surface layer ranging from the surface of the foam molded product to the depth of 1000 μm,
wherein the foam molded product has a density of 0.01 to 0.70 g/cm 3 , and
wherein the foamed region of the first surface layer in which the non-foamed portion is not present has a flattened cell layer comprising cells having an average aspect ratio of 4.0 to 15.0.
2. The foam molded product according to claim 1 , wherein the foam molded product further has, in an inner layer deeper than the depth of 1000 μm from the surface, a circular cell layer comprising cells having an average aspect ratio of 1.0 to 2.0.
3. A method for producing the foam molded product according to claim 1 by using a counter-pressure foam injection molding method, the method comprising: infusing a pressure gas into a cavity of a mold after completely closing the mold; starting injection of a resin component containing a molten-state thermoplastic polyester elastomer together with a chemical foaming agent and/or an inert gas in a supercritical state when a gas pressure in the cavity reaches a prescribed pressure; and rapidly releasing the pressure gas immediately after filling 10 to 55% of a volume of the cavity with the resin component or after a prescribed time.
4. The method for producing the foam molded product according to claim 3 , wherein the inert gas in a supercritical state is nitrogen.