Dainippon Ink and Chemicals, Incorporated

Satoshi Oya

Akio Toyoda

Kosuke Arai

Hidetsugu Sawada

Koji Adachi

Nobuyuki Konishi

Yasutoshi Kakizawa

Hiroshi Ebato

Hideyuki Furuta

Kousuke Arai

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

Disclosed is a heat-sealable lactic acid-based polymer laminates which have heat resistance of 60.degree. C. or above, high sealing strength and good biodegradability and are useful in various films, sheets, packaging containers, etc., comprising a base layer (I) made of a crystallized lactic acid-based polymer (A) and a sealing layer (II) made of an amorphous lactic acid-based polymer (B) having a softening point lower than the melting point of said lactic acid-based polymer (A), and films, sheets or packaging containers with the use of these laminates.

Heat-sealable lactic acid-based polymer laminates

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.

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Ichihara, Japan

Satoshi Oya