Provided is a method capable of producing a retardation film being excellent in axial accuracy, showing small changes in retardation and dimensions at the time of its heating, and having a slow axis in an oblique direction with high production efficiency. The production method for a retardation film of the present invention includes: holding left and right end portions of a film with left and right variable pitch-type clips configured to have clip pitches changing in a longitudinal direction, respectively; preheating the film; causing the clip pitches of the left and right clips to each independently change to obliquely stretch the film; reducing the clip pitches of the left and right clips to shrink the film in the longitudinal direction; and releasing the film from being held with the clips.

The present invention is directed to tamper-evident mesh material, methods of manufacture therefor, and tamper-evident bags manufactured therefrom. The tamper-evident mesh material of the present invention may be used, for example, in the manufacture of a variety of tamper-evident security bags for use in applications where it is desirable to detect any traces or evidence of tampering with or of unauthorized access to the contents of the bag.

The present invention provides a method capable of producing a retardation film having an elongated shape, having high uniaxiality and a high in-plane alignment property, and having a slow axis in an oblique direction with high production efficiency. The production method for a retardation film of the present invention includes: holding left and right end portions of a film with left and right variable pitch-type clips configured to have clip pitches changing in a longitudinal direction, respectively; preheating the film; increasing the clip pitch of the clips on one side and reducing the clip pitch of the clips on another side, while extending a distance between the left and right clips, to obliquely stretch the film; maintaining or reducing the clip pitch of the clips on the one side and increasing the clip pitch of the clips on the another side so that the clip pitches of the left and right clips are equal to each other, while extending the distance between the left and right clips, to obliquely stretch the film; and releasing the film from being held with the clips.

A polymer film for laminating onto a metal substrate (M), the polymer film including an adhesion layer (A) and a bulk layer (B), wherein the adhesion layer is intended for bonding to the metal substrate and includes 20 to 50 wt. % of a non-crystallisable copolyester, 50 to 80 wt. % of polybutylene terephthalate (PBT) and 0-10 wt. % of polymers and additives, and wherein the bulk layer consists of is at least 91 wt. % of PBT and at most 9% of other polymers and additives.

Patterned substrates having a first substrate region that is incrementally mechanically stretched with corrugations and a second substrate region having a plurality of discrete unstretched portions completely surrounded by the first substrate region.

A polymer film for laminating onto a metal substrate (M), the polymer film including an adhesion layer (A) and a bulk layer (B), wherein the adhesion layer is intended for bonding to the metal substrate and includes 20 to 50 wt. % of a non-crystallisable copolyester, 50 to 80 wt. % of polybutylene terephthalate (PBT) and 0-10 wt. % of polymers and additives, and wherein the bulk layer consists of is at least 91 wt. % of PBT and at most 9% of other polymers and additives.

The present invention is directed to tamper-evident mesh material, methods of manufacture therefor, and tamper-evident bags manufactured therefrom. The tamper-evident mesh material of the present invention may be used, for example, in the manufacture of a variety of tamper-evident security bags for use in applications where it is desirable to detect any traces or evidence of tampering with or of unauthorized access to the contents of the bag.

Provided is a lightweight mesh nonwoven fabric having excellent adhesiveness between uniaxially oriented bodies, excellent low-temperature heat sealability, and high strength. A mesh structure 1 includes two or more uniaxially oriented bodies 2, 3; which include a thermoplastic resin layer and a linear low-density polyethylene layer laminated on at least one side of the thermoplastic resin layer; the mesh structure is produced by laminating or weaving the uniaxially oriented bodies through the linear low-density polyethylene layer in such a way that orientation axes L, T of the uniaxially oriented bodies cross; and the mesh structure has properties of: (1) a fiber weight per unit area of 5 to 70 g/m.sup.2, (2) a thickness of the linear low-density polyethylene layer of 2 to 10 m, (3) an adhesive force between the uniaxially oriented bodies of 10 to 60 N, and (4) a tensile strength of 20 to 600 N/50mm.

Patterned substrates having a first substrate region that is incrementally mechanically stretched with corrugations and a second substrate region having a plurality of discrete unstretched portions completely surrounded by the first substrate region.

A method for producing a retardation film comprising the steps of: co-extruding or simultaneously casting a thermoplastic resin A and a thermoplastic resin B to obtain a laminated film comprising a layer of the thermoplastic resin A and a layer of the thermoplastic resin B; and uniaxially stretching the laminated film at least twice to cross a molecular orientation axis in the layer of the thermoplastic resin A and a molecular orientation axis in the layer of the thermoplastic resin B each other at almost right angles.