POLYOLEFIN COMPOSITIONS Russian patent published in 2012 - IPC C08L23/10 C08L23/08 C08J5/18 B29C45/00 

FIELD: chemistry.

SUBSTANCE: invention relates to polyolefin compositions for making films. The composition contains 55-80 wt % propylene homopolymer and 20-45 wt % copolymer of ethylene and one or more C₄-C₁₀-olefins, containing 10-40% of said C₄-C₁₀-olefin(s). The composition has melt flow rate MFR (230°C, 2.16 kg) from 1 to 4 g/10 min, overall content of ethylene from 20 wt % to 40 wt %, overall content of C₄-C₁₀ α-olefin(s) from 6 wt % to 15 wt % and ratio of overall content of ethylene to overall content of C₄-C₁₀ α-olefin(s) equal to or greater than 2.3. The overall content of a fraction which is soluble in xylene at room temperature ranges from 18 wt % to 30 wt %, and the modulus of elasticity in flexure, relating to the reactor-grade composition, is higher than 700 MPa.

EFFECT: disclosed composition is characterised by low melt flow rate values which are suitable for obtaining films cast from a solution, and biaxially oriented films with high gas-permeability (air-permeability), low turbidity (good optical properties) and high modulus of elasticity in flexure (hardness) in addition to said unique balance of properties, impact viscosity at low temperature, lustre and good shrinkage characteristics.

4 cl, 2 tbl, 5 ex