The invention relates to a stretched polymer film made of a polyamide composition comprising a semi-crystalline semi-aromatic polyamide (PPA), wherein the PPA consists of repeat units derived from aromatic dicarboxylic acid comprising at least 80 mole % of terephthalic acid, relative to the total amount of aromatic dicarboxylic acid; and diamine comprising at least 5 mole % 1,4-butanediamine and at least 5 mole % 1,6-hexanediamine, relative to the total amount of diamine, the combined amount of 1,4-butanediamine and 1,6-hexanediamine being at least 60 mole % relative to the total amount of diamine; and 0-2 mole % of other monomeric units, relative to the total amount of aromatic dicarboxylic acid, diamine and other monomeric units. The invention further relates to a process for preparing the polyamide film by melt extrusion and stretching of the film.

A polymeric piezoelectric film including an optically active helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000, wherein: a crystallinity obtained by a DSC method is from 20% to 80%; a standardized molecular orientation MORc measured by a microwave transmission-type molecular orientation meter based on a reference thickness of 50 μm is from 3.5 to 15.0; and in a waveform measured with an inline film thickness meter and representing a relationship between a position in a width direction on the film and a thickness of the film, a number of peaks A is 20 or less per 1,000 mm of a film width, wherein the peaks A have a peak height of 1.5 μm or more and a peak slope of 0.000035 or more.

A polymeric piezoelectric film including an optically active helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000, wherein: a crystallinity obtained by a DSC method is from 20% to 80%; a standardized molecular orientation MORc measured by a microwave transmission-type molecular orientation meter based on a reference thickness of 50 μm is from 3.5 to 15.0; and in a waveform measured with an inline film thickness meter and representing a relationship between a position in a width direction on the film and a thickness of the film, a number of peaks A is 20 or less per 1,000 mm of a film width, wherein the peaks A have a peak height of 1.5 μm or more and a peak slope of 0.000035 or more.

Machine direction oriented multilayer film suitable for preparing labels, comprising a core layer of a bimodal terpolymer and two outer layers comprising HDPE.

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.

A laminated film having a resin layer laminated on at least one surface of a base film. The laminated film is characterized by: the base film being a semi-aromatic polyamide film that has been at least uniaxially stretched; the resin layer having a thickness of 0.03 to 0.5 μm; and the close adhesion between the base film and the resin layer, according to the cross-cut method described in JIS K 5600, being 95% or more.

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.

An oriented film including poly(ethylene-2,5-furandicarboxylate) is produced in a process by preparing a sheet from a poly(ethylene-2,5-furandicarboxylate) resin by heat processing, which sheet has a thickness of at most 2.5 mm; allowing the sheet to cool; and stretching the cooled sheet in at least one direction with a stretch ratio of at least 4/1 at a temperature in the range of 90 to 130° C., yielding an oriented film. The oriented film has a thickness of 1 to 400 μm and a tensile strength at break of at least 100 MPa.

An oriented film including poly(ethylene-2,5-furandicarboxylate) is produced in a process by preparing a sheet from a poly(ethylene-2,5-furandicarboxylate) resin by heat processing, which sheet has a thickness of at most 2.5 mm; allowing the sheet to cool; and stretching the cooled sheet in at least one direction with a stretch ratio of at least 4/1 at a temperature in the range of 90 to 130° C., yielding an oriented film. The oriented film has a thickness of 1 to 400 μm and a tensile strength at break of at least 100 MPa.

A composite film having a high dielectric permittivity engineered particles dispersed in a high breakdown strength polymer material to achieve high energy density.