Block copolymer composition
AssigneeJapan Elastomer Co., Ltd.
InventorsMasahiro Fujiwara, Keiichi Toda
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Abstract
A heat stabilized block copolymer composition which comprises a block copolymer comprising a polymer block mainly composed of a monoalkenyl aromatic compound and a polymer block mainly composed of a conjugated diene compound, the content of the monoalkenyl aromatic compound being 5-95% by weight based on the total weight of the block copolymer, and phenolic stabilizers. By adding two or more specific phenolic stabilizers to a block copolymer of a monoalkenyl aromatic compound and a conjugated diene compound, there can be obtained a block copolymer composition which exhibits excellent heat stability even under being heated at high temperatures, is high in the effect of being inhibited from formation of gel-like materials and is excellent in color tone.
Claims4
A block copolymer composition which comprises (a) a block copolymer comprising a polymer block segment mainly composed of a monoalkenyl aromatic compound and a polymer block segment mainly composed of a conjugated diene compound, the content of the monoalkenyl aromatic compound being 5-95% by weight based on the total weight of the block copolymer, (b) a phenolic stabilizer represented by the following formula (I):
- (wherein R1 and R3 are —CH2—S—R5 in which R5 represents an alkyl group of 1-18 carbon atoms, R2 represents a hydrogen atom or a methyl group, and R4 represents an alkyl group of 1-8 carbon atoms or a cycloalkyl group of 5-12 carbon atoms), and (c) at least one phenolic stabilizer selected from phenolic compounds represented by the following formulas, (II)-(V):
- (wherein R6 is represented by the following formula (VI):
- R7 represents an alkyl group of 2-22 carbon atoms, and R8-R12 each represent a hydrogen atom or an alkyl group of 1-6 carbon atoms, with a proviso that two or more of R8-R12 are alkyl groups), the content of the phenolic stabilizer (b) being more than 0.05 part by weight and less than 0.6 part by weight and that of the phenolic stabilizer (c) being not less than 0.05 part by weight and not more than 0.8 part by weight based on 100 parts by weight of the block copolymer (a).
Dependencies are inferred from the claim text.