RIGID BLOWN FILM Russian patent published in 2023 - IPC C08J5/18 B29L7/00 C08F210/06 C08F210/08 C08F4/6592 

FIELD: blown film for food and/or medical packaging.

SUBSTANCE: film contains at least 95.0 wt.% propylene-butene-1 random copolymer and has (i) a longitudinal and transverse tensile modulus in accordance with ISO 527-3 at 23°C measured on 50 mcm blown films, ranging from 700 to 1800 MPa. In this case, the propylene-butene-1 random copolymer has: (a) melt flow rate (MFR2 (MFR at a load of 2.16 kg); 230°C/2.16 kg; measured in accordance with ISO 1133), in the range from 0.5 to less than 4.0 g/10 min, (b) 1-butene content in the range from 2.0 to 15.0 wt.% based on the total mass of the statistical propylene-butene-1 copolymer and (c) the xylene cold soluble (XCS) fraction measured according to ISO 16152 at 25°C, in the range from 0.10 to 2.80 wt.%, (d) molecular weight distribution (Mw/Mn) less than 4.5, and (e) the specified copolymer is obtained using a single-site catalyst.

EFFECT: provision of a polypropylene-based blown film with good mechanical properties, such as rigidity at a low seal initiation temperature (SIT), as well as good optical properties, such as low haze and high transparency, improved sealing properties, such as a low seal initiation temperature (SIT) and high hot tightening force (HTF), and additionally having a low amount of hexane soluble fraction and high optical-mechanical properties (OMA).

15 cl, 4 tbl, 8 ex