PURPOSE: An improving agent having good dispersibility in a thermoplastic resin (e.g., vinyl chloride resin) and capable of providing a resin composition excellent in impact resistance, and moldability, comprising a multilayer (at least three-layered) graft copolymer in which the Tg (glass transition temperature) of the outermost layer is 0°C or below.
CONSTITUTION: An impact resistance-improving agent prepared by forming, by graft-polymerization, at least two graft layers on a polybutadiene elastomer (with the weight ratio of other vinyl compounds to butadiene of at most one) containing 0W5wt% crosslinking agent. Each of the graft layers is formed from a polymer of an alkyl (meth)acrylate, aromatic vinyl compound, vinyl cyanide compound of butadiene, containing 0W5wt% crosslinking agent, and the Tg of the polymer of the outermost layer is 0°C or below, and the Tg of the polymer next to the outermost layer is 60°C or above.
UEDA KAZUO
KITAI KIYOKAZU
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