MULTILAYER FILM FOR PACKING CHEESE Russian patent published in 2017 - IPC B32B27/06 B32B27/32 B32B27/34 B65D65/40 B65D85/76 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry and concerns a multilayer polymer film for packing cheese. Film is made by co-extrusion and is stretched along two axes by triple blowing. Film contains the first outer layer, if seen from outside to inside, and a second protective outer layer made from a ethylene and vinyl acetate (EVA) copolymer and from a mixture thereof with very low density polyethylene (VLDPE) respectively, two adhesive layers made of VLDPE, copolymer of EVA and low-density linear polyethylene (LLDPE), modified with maleic anhydride, and a middle layer. Middle layer is bound by one of its surfaces to first adhesive layer arranged between first outer layer and middle layer, and by other side – with second adhesive layer arranged between protective second outer layer and middle layer. Middle layer comprises three layers of polyamide (PA), between their adjacent layers it contains one additional layer made of a mixture of PA with amorphous polyamide (APA) at a ratio of 85:15 wt%, respectively, and a second additional layer of LLDPE, modified with maleic anhydride, middle layer contains between layer of a mixture of PA with APA and layer of polyamide. Preferred design when second additional layer is made from LLDPE, modified with maleic anhydride, and nanoclay at ratio, wt%: 99.99–99.00 and 0.01–1.0, respectively. Invention reduces permeability of multilayer film for packing cheese to water vapour by 3.9–4.5 times, improves thermosetting properties in longitudinal direction by 48.6 %, which reduces coefficient of anisotropy of thermosetting properties to 1.08.

EFFECT: reduced permeability and coefficient of anisotropy of multilayer film.

1 cl, 7 tbl, 1 ex