Dainippon Ink and Chemicals, Incorporated

Kosuke Arai

Satoshi Oya

Hidetsugu Sawada

Akio Toyoda

Koji Adachi

Nobuyuki Konishi

Yasutoshi Kakizawa

Hiroshi Ebato

Hideyuki Furuta

Hirofumi Yamada

Yoshiaki Murata

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 shrink film is provided which is superior in glossiness, mechanical strength, and rigidity, and which is also provided with a property of preventing natural shrinkage. The shrink film with excellent properties is produced by using a resin composition which is obtained by graft polymerization of copolymers of styrene and butadiene with styrene, methylmethacrylate, and butylacrylate. The thus obtained resin composition is extruded after melting and kneading, and drawn into a film in two directions, and exposed at a temperature within a temperature range for the thermal setting so as to obtain the orientation according to ASTM D1504 of the shrink film in range of 1.5 to 5.0 MPa.

Shrink film and method of making the same

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.

Multilayered biaxially-oriented styrene based resin sheet and method for

A process for producing a lactic acid-based copolyester by the ring-opening copolymerization and transesterification of a lactide (A) with an aromatic polyester (B) and/or an aliphatic polyester (C) in the presence of a ring-opening polymerization catalyst (D), and a packaging material comprising the lactic acid-based copolyester obtained by the process are disclosed. According to the present invention, a lactic acid-based degradable copolyester which has a sufficiently high molecular weight and satisfactory toughness and also has suitable rigidity, pliability, and transparency according to applications can be produced. Further, a general-purpose packaging material, e.g., a sheet or film, which comprises the lactic acid-based copolyester produced by the process and is excellent in formability, degradability, and transparency can also be produced.

Process for producing lactic acid-based copolyester and packaging

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Chiba, Japan

Kosuke Arai