US Patent 7648737 Stretched laminate film and method of producing the same

The present invention provides a stretched laminate film with oxygen-gas barrier properties which includes a layer (a) formed from a composition of a polycarboxylate-based polymer (A) and a plasticizer (B), a layer (c) containing a multivalent metal compound (C) and a layer (b) formed from a thermoplastic resin, which film includes at least one layer forming unit where the layer (a) and the layer (c) are adjacent to each other, and in which film at least the layer (a) and the layer (b) are stretched with a surface stretch ratio of 1.1 to 100. By means of carrying out an applying step and a stretching step according to a production method of the present invention, the layer formed from the polycarboxylate-based polymer including the plasticizer can be made thinner, although making the layer thinner has been difficult to achieve as long as only the application is carried out.