METHOD OF PRODUCING SILK FIBROIN BASED FILM FOR MAKING CONTACT LENSES Russian patent published in 2012 - IPC D01F4/02 G02C7/04 

FIELD: chemistry.

SUBSTANCE: method involves preparation of silk fibroin, including grinding, dissolution in lithium bromide while heating, dialysis with removal of lithium bromide from the dissolved silk fibroin through a semipermeable membrane, drying to form a film, followed by dissolution thereof in 1,1,1,3,3,3-hexafluoro-2-propanol, and then mixing with dissolved polymethylmethacrylate in 1,1,1,3,3,3-hexafluoro-2-propanol. The film is then cast on a fluoroplastic substrate with removal of solvent, thereby forming a 60-70 mcm thick film, followed by drying at temperature 30-35°C for 5-6 hours with forced ventilation, with subsequent treatment in ethanol while vertically immersing the film into a bath at a frequency of 15-20 immersions per hour, for 15-20 minutes.

EFFECT: high strength, optical transmission coefficient, oxygen permeability, while retaining moisture content, limiting wetting angle in film materials for making soft contact lenses.

5 cl, 4 tbl