Dainippon Ink and Chemicals, Incorporated

Nobuyuki Konishi

Akio Toyoda

Hidetsugu Sawada

Kosuke Arai

Satoshi Oya

Koji Adachi

A multilayered biaxially-oriented styrene based resin sheet comprises; a styrene based resin layer (A) as at least two outer layers formed by the polymerization of methacrylic acid in a weight proportion of 1&tilde;3.5% and styrene, and a styrene based resin layer (B) formed from polystyrene which is sandwiched between the outer layers and for which the loss tangent (tan &dgr;) maximum peak value temperature for dynamic viscoelasticity measurement is 6.5&tilde;25&deg; C. lower than that for the resin of the resin layer (A). The sheet has excellent properties of transparency and external appearance, can be reused by recovering and moreover does not suffer from raindrop occurrence by secondary forming.

Multilayered biaxially-oriented styrene based resin sheet and method for production thereof

A multilayered biaxially-oriented styrene based resin sheet comprises; a styrene based resin layer (A) as at least two outer layers formed by the polymerization of methacrylic acid in a weight proportion of 1-3.5% and styrene, and a styrene based resin layer (B) formed from polystyrene which is sandwiched between the outer layers and for which the loss tangent (tan .delta.) maximum peak value temperature for dynamic viscoelasticity measurement is 6.5-25.degree. C. lower than that for the resin of the resin layer (A). The sheet has excellent properties of transparency and external appearance, can be reused by recovering and moreover does not suffer from raindrop occurrence by secondary forming.

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Chiba, Japan

Nobuyuki Konishi