Sumitomo Chemical Company, Limited

Ryosuke Kurokawa

Nobuhiro Natsuyama

Yukari Hiraguchi

A thermoplastic elastomer composition including (A) ethylene rubber by 10 to 90 wt %, and (B) propylene polymer by 10 to 90 wt %, where a total amount of the thermoplastic elastomer composition is 100 wt %, is provided. A pressed sheet obtained by press-molding the thermoplastic elastomer composition under molding conditions has a sink-in temperature of 115&#xb0; C. or higher. The sink-in temperature is measured based on JIS K7196-1991 as a temperature measured when a pressure load sinks in from a sheet surface by 100 &#x3bc;m. The molding conditions are such that the thermoplastic elastomer composition is hot press molded at a temperature of 200&#xb0; C. with a maximum pressure of 10 MPa for 5 min, and thereafter cold press molded at a temperature of 23&#xb0; C. with a maximum pressure of 10 MPa for 5 min, so as to prepare the pressed sheet.

Thermoplastic elastomer composition

A thermoplastic elastomer composition contains components (A), (B), (C), and (D), wherein the weight ratio of component (C) to component (D) is &#x2265;0.1 and &#x3c;2, component (A) is an ethylene random copolymer containing &#x2265;50% and &#x2264;90% of a monomer unit derived from ethylene by weight relative to the component (A) and a monomer unit derived from at least one monomer selected from the group consisting of &#x3b1;-olefins having a number of carbon atoms of &#x2265;3 and &#x2264;10, component (B) is a polymer containing &#x3e;50% and &#x2264;100% of a monomer unit derived from propylene by weight relative to the component (B), component (C) is a copolymer containing an ethylene polymerization block and an ethylene-&#x3b1;-olefin copolymerization block, and component (D) is an ethylene polymer containing &#x3e;90% and &#x2264;100% of a monomer unit derived from ethylene by weight relative to the component (D).

There is provided a thermoplastic elastomer composition from which a molded article excellent in flame retardancy, tensile properties, softness, and appearance can be obtained and by which a mold is hardly polluted during its molding. The thermoplastic elastomer composition includes at least one selected from an ethylene copolymer containing monomer units derived from ethylene and monomer units derived from at least one selected from propylene and &#x3b1;-olefins having 4 to 10 carbon atoms (component (A)) and a copolymer containing monomer units derived from an aromatic vinyl compound and monomer units derived from a conjugate diene compound (component (B)), a propylene polymer (component (C)), a phosphoric acid salt compound (component (D)), a phosphoric acid ester (component (E)), and a metal oxide (component (F)).

The present invention provides a thermoplastic elastomer composition containing: (A-1) a crosslinked ethylene copolymer containing monomer units derived from ethylene and monomer units derived from propylene and/or &#x3b1;-olefins having 4 to 10 carbon atoms, (B) a propylene polymer containing monomer units derived from propylene and having a content of the monomer units derived from propylene of greater than 50% by weight, and (E) an inorganic filler having an average particle diameter of less than 1.0 &#x3bc;m. In the thermoplastic elastomer composition, the content of the component (E) is 10% by weight to 23% by weight and the Shore A durometer hardness of the thermoplastic elastomer composition is 30 to 99. Molded articles formed of the thermoplastic elastomer composition are superior in adhesiveness to thermoplastic elastomer molded articles.

There are provided a thermoplastic elastomer composition from which a molded article excellent in softness, flame retardancy, tensile properties, and appearance can be obtained and which is excellent in flowability, and a molded article thereof. The thermoplastic elastomer composition includes a thermoplastic elastomer obtained by reacting an ethylene copolymer comprising monomer units derived from ethylene and monomer units derived from at least one selected from the group consisting of propylene and &#x3b1;-olefins having 4 to 10 carbon atoms (component (A)), a propylene polymer (component (B)), and a crosslinking agent, a phosphoric acid salt compound (component (C)), a metal oxide including a metal having an atomic weight of 22 to 64 or a metal hydroxide including a metal having an atomic weight of 22 to 64 (component (D)), and a polyhydric compound (component (E)).

A flame-retardant thermoplastic elastomer composition is provided to produce a molded article possessing mechanical properties, flame retardancy and softness inherently possessed by a molted article obtained from a thermoplastic elastomer composition containing a mineral oil-based softening agent and a flame retardant and fails to stain a mold after injection molding. A production method includes step (1) obtaining a thermoplastic elastomer composition by dynamically crosslinking a polymer mixture (A) containing an ethylene-&#x3b1;-olefin-based copolymer rubber (A1) and a propylene-based polymer (A2) in the presence of a mineral oil-based softening agent (C) and a crosslinking agent (D), and step (2) kneading the thermoplastic elastomer composition, a halogen-free flame retardant (E), zinc oxide (F), and a thermoplastic resin with a polar group (G). The amounts of the components satisfy condition (p) when starting the dynamic crosslinking in step (1) and satisfy condition (q) when starting the kneading in step (2), respectively.

Method for producing flame-retardant thermoplastic elastomer composition

A method is provided for producing a flame retardant thermoplastic elastomer composition, wherein the method includes (1) a step of preparing a thermoplastic elastomer composition by dynamically vulcanizing a thermoplastic elastomer composition precursor containing (A) an ethylene-&#x3b1;-olefin-based copolymer rubber, (B) a propylene-based polymer and (C) a mineral oil-based softening agent in the presence of (D) a crosslinking agent, and (2) a step of kneading the thermoplastic elastomer composition, (E) a halogen-free flame retardant, (F) a zinc oxide, and optionally (G) a polyhydric compound.

Disclosed is a thermoplastic elastomer composition that will provide little load on the environment and has superior mechanical characteristics, the composition being obtained by melt-kneading 10 to 90 parts of ethylene-&#x3b1;-olefin based copolymer rubber (A), 1 to 50 parts of non-petroleum source-derived thermoplastic resin (B), 0.01 to 20 parts of modified ethylene-based copolymer (C), 1 to 50 parts of propylene-based polymer (D), 0.001 to 5 parts of crosslinking agent (E), and 0 to 50 parts of a mineral oil-based softening agent (F), wherein the amounts of components (A), (B), (D) and (F) are amounts in weight calculated where the total amount of components (A), (B), (D) and (F) is considered to be 100 parts, and the amounts of components (C) and (E) are amounts in weight calculated where the total amount of components (A), (B), (D) and (F) is considered to be 100 parts.

Disclosed is a thermoplastic elastomer composition that will provide little load on the environment and has superior mechanical characteristics, the composition being obtained by melt-kneading 10 to 90 parts of ethylene-&#x3b1;-olefin based copolymer rubber (A), 1 to 50 parts of non-petroleum source-derived thermoplastic resin (B), 1 to 50 parts of modified propylene-based copolymer (C), 1 to 50 parts of propylene-based polymer (D), 0.001 to 5 parts of crosslinking agent (E), and 0 to 50 parts of mineral oil-based softening agent (F), wherein the amounts of components (A), (B), (C), (D), and (F) are amounts in weight calculated where the combined amount of components (A), (B), (C), (D) and (F) is considered to be 100 parts by weight, and the amount of component (E) is an amount in weight calculated where the combined amount of components (A), (B), (C), (D), and (F) is considered to be 100 parts by weight.

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Ichihara, Japan

Ryosuke Kurokawa