RANDOM COPOLYMER CC Russian patent published in 2023 - IPC C08F210/06 C08F2/01 C08F4/6592 C08J5/18 B32B15/85 B32B27/08 

FIELD: random copolymer C₂C₃.

SUBSTANCE: group of inventions is related to a C₂C₃ random copolymer with a bimodal distribution of comonomer content, exhibiting improved sealing properties due to a low seal initiation temperature (SIT) and a high peel force when determining hot tack (HTF), a method for its preparation and use. The C₂C₃ random copolymer (RACO) with a bimodal distribution of comonomer content has: (a) an ethylene content of 2.8 to 4.9 wt.%, (b) melt flow index PTR₂ (230°С/2.16 kg), measured in accordance with ISO 1133, from 1.0 to 20.0 g/10 min, (c) melting point Tm, determined by differential scanning calorimetry (DSC) in accordance with ISO 11357, from 115 to 130°C, and (d) a xylene cold soluble (XCS) fraction content of from 0.5 wt.% to less than 15.0 wt.%. Described is a method for producing the C₂C₃ random copolymer (RACO), which is obtained by polymerizing propylene and ethylene in a sequential polymerization process comprising at least two reactors connected in series in presence of a metallocene catalyst and a cocatalyst containing at least one or two compounds Group 13 metal. The use of the C₂C₃ random copolymer (RACO) to make an article, a sterilizable or sterilized article, the use of a sterilizable or sterilized article of films as a sealing layer in a multilayer film, and a flexible packaging system selected from bags or pouches for food and medicinal products, including sterilizable or sterilized film are also described.

EFFECT: C₂C₃ random copolymers (RACO) according to the invention are characterized by an advantageous combination of low seal initiation temperature (SIT), high peel force when determining hot tack and good optical properties such as low turbidity and high transparency, as well as good resistance to sterilization.

20 cl, 8 tbl, 5 ex