Thermoplastic elastomer composition for core back type injection foaming and injection foaming method using the same

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene•α-olefin-based copolymer (1) and a crystalline polyethylene-based resin (2), wherein said crystalline polyethylene-based resin (2) constitutes a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1);

• a blowing agent-containing resin in which a blowing agent (4) is kneaded in an olefin resin (6);
• and
• a nucleating agent-containing resin in which a nucleating agent (5) is kneaded in an olefin resin (6);
• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene α-olefin-based copolymer (1), a crystalline polyethylene-based resin (2) and a following block copolymer (3), wherein said crystalline polyethylene-based resin (2) and said block copolymer (3) constitute a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1), a blowing agent (4) and a nucleating agent (5);

• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• said block copolymer (3) is a block copolymer having a crystalline ethylene polymer block and a block having a higher compatibility to said ethylene α-olefin-based copolymer (1) than to said crystalline polyethylene-based resin (2);
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene•α-olefin-based copolymer (1), a crystalline polyethylene-based resin (2) and a following block copolymer (3), wherein said crystalline polyethylene-based resin (2) and said block copolymer (3) constitute a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1);

• a blowing agent-containing resin in which a blowing agent (4) is kneaded in an olefin resin (6);
• and
• a nucleating agent-containing resin in which a nucleating agent (5) is kneaded in an olefin resin (6);
• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• said block copolymer (3) is a block copolymer having a crystalline ethylene polymer block and a block having a higher compatibility to said ethylene•α-olefin-based copolymer (1) than to said crystalline polyethylene-based resin (2);
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene•α-olefin-based copolymer (1) and a crystalline polyethylene-based resin (2), wherein said crystalline polyethylene-based resin (2) constitutes a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1);

• (i) an organic blowing agent-containing resin in which an organic blowing agent (4a) is kneaded in an olefin resin (6) and an inorganic blowing agent-containing resin in which an inorganic blowing agent (4b) is kneaded in an olefin resin (6), or (ii) an organic/inorganic blowing agent-containing resin in which an organic blowing agent (4a) and an inorganic blowing agent (4b) are kneaded in an olefin resin (6);
• and
• a nucleating agent-containing resin in which a nucleating agent (5) is kneaded in an olefin resin (6);
• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene•α-olefin-based copolymer (1), a crystalline polyethylene-based resin (2) and a following block copolymer (3), wherein said crystalline polyethylene-based resin (2) and said block copolymer (3) constitute a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1), an organic blowing agent (4a), an inorganic blowing agent (4b) and a nucleating agent (5);

• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• said block copolymer (3) is a block copolymer having a crystalline ethylene polymer block and a block having a higher compatibility to said ethylene•α-olefin-based copolymer (1) than to said crystalline polyethylene-based resin (2);
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.

A thermoplastic elastomer composition for core-back system foam injection molding, comprising a thermoplastic elastomer which includes an ethylene•α-olefin-based copolymer (1), a crystalline polyethylene-based resin (2) and a following block copolymer (3), wherein said crystalline polyethylene-based resin (2) and said block copolymer (3) constitute a three-dimensional network structure in a matrix formed by said ethylene•α-olefin-based copolymer (1);

• (i) an organic blowing agent-containing resin in which an organic blowing agent (4a) is kneaded in an olefin resin (6) and an inorganic blowing agent-containing resin in which an inorganic blowing agent (4b) is kneaded in an olefin resin (6), or (ii) an organic/inorganic blowing agent-containing resin in which an organic blowing agent (4a) and an inorganic blowing agent (4b) are kneaded in an olefin resin (6);
• and
• a nucleating agent-containing resin in which a nucleating agent (5) is kneaded in an olefin resin (6);
• wherein said thermoplastic elastomer has a melt flow rate of 5 g/10 min or more at a temperature of 230° C. and a load of 10 kg, and a melt tension of 3.0 gf or more at a temperature of 210° C. and a pulling rate of 2 m/min;
• said block copolymer (3) is a block copolymer having a crystalline ethylene polymer block and a block having a higher compatibility to said ethylene•α-olefin-based copolymer (1) than to said crystalline polyethylene-based resin (2);
• and
• characterized by said thermoplastic elastomer composition for core-back system foam injection molding is injected into a cavity space of a metal mold and is foamed by opening the metal mold thereby expanding said cavity space to form an injection foaming product having a skin layer and a foamed layer.