MULTI-LAYER SHRINK FILMS WITH PVDC BARRIER Russian patent published in 2018 - IPC B32B27/08 B32B27/30 B32B27/32 B32B27/34 B32B27/36 

FIELD: packaging industry.

SUBSTANCE: invention relates to multi-layer barrier shrink films and flexible containers manufactured therefrom, such as bags, sacks and the like, suitable for packaging products, particularly food products. Multilayer co-extruded biaxially oriented barrier shrinkable packaging film comprises at least one outer heat sealable layer (a), one layer (b) not directly adjacent to the heat-sealable layer (a), wherein said layer (b) comprises one or more aromatic (co) polyesters having a melting point higher than 225 °C, 230 °C or 235 °C, at least one internal gas-impermeable layer (c) containing polyvinylidene chloride, wherein said film has A) a general free shrinkage at 85 °C of at least 45 %, B) the maximum shrinkage stress in both the longitudinal and transverse directions is at least 20 kg/cm² and C) the residual shrinkage stress at 5 °C in both longitudinal and transverse directions of at least 25 kg/cm², while the total free shrinkage is measured according to ASTM D2732, the maximum shrinkage stress and the residual shrinkage stress are measured by the method according to the description of the present invention.

EFFECT: these films are characterized by special shrink properties that ensure tight packaging with a reduction in moisture loss due to leakage from the product packed into them: in addition, the bags made from such films have excellent optical properties and high resistance to improper handling.

35 cl, 2 dwg, 5 tbl