POLARISING FILM AND METHOD OF OBTAINING IT Russian patent published in 2014 - IPC G02B5/30 

FIELD: chemistry.

SUBSTANCE: polarising film consists of oriented molecules of a block copolymer of polyvinyl alcohol and polyvinylene, obtained by acid-catalysed thermal dehydration of oriented molecules of polyvinyl alcohol, and additionally contains phosphotungstic acid. A method of production consists in formation of a film of polyvinyl alcohol from a water solution of polyvinyl alcohol and an acid catalyst of thermal dehydration of the said polymer, uniaxial stretching and annealing the said film. As the acid catalyst used is phosphotungstic acid in an amount of 10-30% relative to the polyvinyl alcohol weight. The film is stretched 4-7-fold relative to its initial length and annealed at a temperature of 120-140°C for 1-15 min.

EFFECT: similar optic properties throughout the whole area, increased resistance to moisture and heat, ensuring simplicity, efficiency and environmental friendliness of the film production.

3 cl