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US 4,377,665 AGranted
Process for producing block copolymer resin
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsToshinori Shiraki, Akio Yamori, Hideo Morita
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AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsToshinori Shiraki, Akio Yamori, Hideo Morita
Estimating the term…
In producing a block copolymer resin having vinyl aromatic hydrocarbon polymer blocks such as of styrene and polymer blocks primarily composed of conjugated diene such as of butadiene successively through living polymers using an organolithium compound as a catalyst in an aliphatic solvent, the vinyl aromatic hydrocarbon monomer for forming the vinyl aromatic hydrocarbon polymer block is added at a controlled rate, at the stage when the vinyl aromatic hydrocarbon content in the polymer formed has reached a certain value, higher than the polymerization rate of the vinyl aromatic hydrocarbon monomer at the polymerization temperature but at a rate which can maintain the solubility parameter of the liquid phase portion in the polymerization system at 7.7 or less, whereby a block copolymer resin with good transparency and impact strength can be produced with good productivity.
A process for producing a block copolymer resin comprising at least one vinyl aromatic hydrocarbon polymer block and at least one polymer block primarily composed of a conjugated diene, the weight ratio of vinyl aromatic hydrocarbon to conjugated diene being 55:45 to 95:5, using an organolithium compound as a catalyst in a solvent composed principally of an aliphatic hydrocarbon, wherein the improvement comprises adding continuously a monomer of a vinyl aromatic hydrocarbon to be added for formation of the vinyl aromatic hydrocarbon polymer block, at a stage of polymerization at which the vinyl aromatic hydrocarbon content in the polymer formed has reached 55% by weight or more, at a rate which is higher than the substantial average polymerization rate of said monomer at the polymerization temperature and yet maintains the solubility parameter of the liquid phase portion in the polymerization system at substantially not higher than 7.7 to further continue polymerization.
A process for producing a block copolymer resin comprising at least one vinyl aromatic hydrocarbon polymer block and at least one polymer block primarily composed of a conjugated diene, the weight ratio of vinyl aromatic hydrocarbon to conjugated diene being 55:45 to 95:5, using an organolithium compound as a catalyst in a solvent composed principally of an aliphatic hydrocarbon, comprising the steps of:
Dependencies are inferred from the claim text.