Multilayer stretched product
At least one layer of an aliphatic polyester resin, which is biodegradable and is also excellent in gas-barrier property and mechanical strength, is laminated with another thermoplastic resin layer to provide a satisfactory multilayer stretched product. The aliphatic co-polyester (A) has a crystallization temperature Tc1 due to crystallization in the course of heating, which is higher than the glass transition temperature Tg of another thermoplastic resin.
1 . A multilayer stretched product, comprising: stretched layers including a layer of an aliphatic co-polyester(A) and a layer of a thermoplastic resin(B); wherein said aliphatic co-polyester(A) has a crystallization temperature Tc1 of at least ca. 96° C., said crystallization temperature Tc1 being defined as a heat-evolution peak temperature due to crystallization detected in the course of heating from amorphous state at a temperature-raising rate of 10° C./min. by means of a differential scanning calorimeter, and said thermoplastic resin(B) has a glass-transition temperature Tg which is lower than the Tc1:
2 . A multilayer stretched product according to claim 1 , wherein the Tc1 of the aliphatic co-polyester (A) is at least ca. 100° C.
3 . A multilayer stretched product according to claim 1 , wherein the Tg of the thermoplastic resin(B) is ca. 64 to 120° C.
4 . A multilayer stretched product according to claim 3 , wherein the thermoplastic resin (B) comprises a polyester resin.
5 . A multilayer stretched product according to claim 1 , wherein the crystallization temperature Tc1 of the aliphatic co-polyester(A) is ca. 100 to 135° C.
6 . A multilayer stretched product according to claim 1 , wherein the aliphatic co-polyester(A) exhibits a crystallization temperature Tc2 of at most ca. 170° C. defined as a heat-evolution peak temperature due to crystallization detected in the course of cooling from a molten state at a temperature-lowering rate of 10° C./min. by means of a differential scanning calorimeter.
7 . A multilayer stretched product according to claim 1 , wherein the aliphatic co-polyester (A) is a copolymer of glycolide with a monomer copolymerizable therewith.
8 . A multilayer stretched product according to claim 1 , wherein the aliphatic co-polyester (A) is a copolymer of at least two monomers copolymerizable with each other selected from the group consisting of glycolide (GL), lactide (LA), trimethylene carbonate (TMC) and caprolactone (CL).
9 . A multilayer stretched product according to claim 1 , wherein the layer of the aliphatic co-polyester (A) is disposed as an intermediate layer.
10 . A multilayer stretched product according to claim 9 , wherein the aliphatic co-polyester (A) layer is disposed as an intermediate layer between a pair of the thermoplastic resin(B) layers.
11 . A multilayer stretched product according to claim 10 , wherein the thermoplastic resin (B) comprises a polyester resin.
12 . A multilayer stretched product according to claim 4 , wherein the thermoplastic resin (B) comprises an aromatic polyester resin.
13 . A multilayer stretched product according to claim 1 , assuming a form of hollow vessel.
14 . A multilayer stretched product according to claim 13 , wherein the hollow vessel has been formed by blow molding.
15 . A multilayer stretched product according to claim 14 , wherein the hollow vessel has been formed by blow molding according to a cold parison method.
16 . A multilayer stretched product according to claim 14 , wherein the hollow vessel has been formed by blow molding according to a hot parison method.
17 . A multilayer stretched product according to claim 1 , assuming a stretched laminate film.
18 . A multilayer stretched product according to claim 1 , assuming a form of (deep) drawn container.