Kuraray Co., Ltd.

Hajime Kitano

Koichi Wada

Hideo Takamatsu

Kenji Shachi

Mizuho Maeda

Noboru Higashida

Masanari Uno

A flame-retardant composition includes: a powdery acid-modified hydrogenated block copolymer (a) having a bulk density of 0.1 to 0.4 g/ml and which is a hydrogenated block copolymer modified by addition of an unsaturated carboxylic acid or a derivative thereof, the hydrogenated block copolymer comprises a polymer block A composed mainly of a vinyl aromatic compound unit and a polymer block B composed mainly of a conjugated diene unit, and has a weight average molecular weight of 50,000 to 500,000; a polyolefin resin (b); a non-aromatic rubber softener (c); and a metal hydrate (d). The flame-retardant composition contains the components (a), (b), (c) and (d) in proportions that satisfy the following relationships (1) to (3):0.1&#x2266;/()&#x2266;0.9&#x2003;&#x2003;(1)0.05&#x2266;/()&#x2266;0.5&#x2003;&#x2003;(2)0.4&#x2266;/()&#x2266;0.75&#x2003;&#x2003;(3)wherein Wa, Wb, Wc and Wd represent masses of the acid-modified hydrogenated block copolymer (a), the polyolefin resin (b), the non-aromatic rubber softener (c) and the metal hydrate (d), respectively.

Flame-retardant composition

The present invention concerns a polymer composition comprising: a block copolymer (a) including a polymer block A, which is composed mainly of an &#x3b1;-methylstyrene, and a hydrogenated or unhydrogenated polymer block B, which is composed of a conjugated diene or isobutylene and has a weight average molecular weight of 30,000 to 200,000; an acrylic resin (b); and a softener (c), wherein proportions (by mass) of the respective components in the polymer composition are such that each of the following relationships (1) and (2) holds:0.05&#x2266;2 and&#x2003;&#x2003;(1)/()&#x2266;0.5&#x2003;&#x2003;(2)wherein Wa, Wb, and Wc represent amounts (by mass) of the block copolymer (a), the acrylic resin (b) and the softener (c), respectively. The polymer composition obtainable in accordance with the present invention is favorable in terms of such physical properties as formability, scratch resistance, abrasion resistance, flexibility, mechanical strength, rubber elasticity, and transparency and exhibits these properties in a well-balanced manner. By exploiting these favorable properties, the polymer composition can be effectively used in a wide range of applications, including stretchable materials, laminates, and foams.

Polymer composition and uses thereof

A polymer composition obtainable by subjecting a particular crosslinkable polymer composition to dynamic crosslinking. The crosslinkable polymer composition contains. (a) a block copolymer comprising two or more polymer blocks of a vinyl aromatic compound and one or more (hydrogenated) polymer blocks of a conjugated diene; (b) an olefin copolymer having a density of 0.88 to 0.92 g/cmand obtained through copolymerization of ethylene and an &#x3b1;-olefin having 4 to 12 carbon atoms; (c) a softening agent; and (d) an organic peroxide in respective amounts that satisfy the following relational expressions {circle around (1)} to {circle around (3)}:0.66&#x2266;Wb/Wa&#x2266;4{circle around (1)}0&#x2266;/()&#x2266;0.25{circle around (2)}0.001&#x2266;/()&#x2266;0.01{circle around (3)}wherein Wa, Wb, Wc and Wd represent the respective amounts (by mass) of the components (a), (b), (c) and (d), that are present in the polymer composition prior to the dynamic crosslinking. The polymer composition of the present invention is based on a thermoplastic elastomer that has various improved properties, including moldability, abrasion resistance, scratch resistance, hydrolysis resistance, softness, rubber elasticity, grip, shock absorbance, oil resistance, lightweightness and mechanical strength, and has these properties in a well-balanced manner.

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Ibaraki, Japan

Hajime Kitano