PURPOSE: To obtain a block copolymer which exerts a good balance of rheological properties, physical adhesion properties and mechanical properties of a hot melt composition, by allowing it to have a specific structure.
CONSTITUTION: A block polymer is derived from a vinyl aromatic monomer and a conjugated diene and has a structure of A-B-C-D. Here, the total content of the vinyl aromatic is from 10 to 40 wt.% and from 1 to 20% of the total conjugated diene is polymerized in a 1, 2 or 3, 4 addition. A is predominantly a poly(vinyl aromatic) block, B is predominantly a poly(conjugated diene) block and C is a block comprising the conjugated diene present in B and the vinyl aromatic constituting D, wherein the conjugated diene is tapered and the vinyl aromatic content increases in the direction of D. The weight ratio of the conjugated diene present in B and the conjugated diene present in C is from 5:5 to 9:1, and the total apparent molecular weight is from 130,000 to 300,000.
JIYAKURIINU MAAGARESA FUEURINK
BURIJITSUTO MARIA RUUDOFUIKA K
YARUUN FUAN UESUTORENEN
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