SEMI-AROMATIC POLYAMIDE FILM AND METHOD FOR OBTAINING THE FILM Russian patent published in 2022 - IPC B29C55/12 C08J5/18 B29K77/00 

FIELD: semi-aromatic polyamide film.

SUBSTANCE: the invention relates to a method for obtaining semi-aromatic polyamide film and to the electronic material and the optical component that include this film. A semi-aromatic polyamide film has a thermal shrinkage coefficient in the longitudinal direction of the film, S_MD, from - 0,1 up to 1,5% and thermal shrinkage coefficient in width direction, S_TD, from - 0,1 up to 1,5% when measured in conditions of 250°C for 5 minutes, tensile elongation to break 70% or more in the longitudinal direction and the direction of the width, muddiness 14% or less. The method for producing said film includes biaxial stretching of an unstretched film of semi-aromatic polyamide having a crystallization enthalpy of 20 J/g or more. Stretch ratio is 2-3,5 times longitudinally and 2-4 times in the width direction. Tensile strain rate in the longitudinal and width directions is over 400%/min and 12000%/min or less. The tensile temperature is the glass transition temperature of the semi-aromatic polyamide or more and the glass transition temperature of the semi-aromatic polyamide +50°C or less. After biaxial stretching the film is heat-fixed at a temperature of 260-280°C, and then the film is subjected to relaxation treatment at the relaxation rates of 1-10% in the longitudinal direction and 1-12% in the width direction.

EFFECT: resulting film of semi-aromatic polyamide has a significantly reduced coefficient of thermal shrinkage in the longitudinal direction and greatly improved elongation at break in the direction of the film width.

5 cl, 6 tbl, 38 ex