MIXTURES OF POLYOLEFIN RESINS FOR HIGH RESISTANCE TO CRACKING UNDER STRESS AND GOOD RECYCLABILITY Russian patent published in 2022 - IPC C08L23/06 C08L23/08 

FIELD: chemistry.

SUBSTANCE: present invention relates to a polyethylene composition for the production of a molded product. The polyethylene composition contains a mixture obtained in a melt. The specified mixture contains: a) the first multimodal polyethylene characterized by medium average-mass molecular weight from more than 90,000 to 200,000 g/mol or high average-mass molecular weight from more than 200,000 to 1,000,000 g/mol, density in the range from more than 0.950 to 0.965 g/cm³ according to ISO 1183, and MFR₂ value from 0.3 to 2.0 g/10 min according to ISO 1133, and b) the second multimodal polyethylene characterized by high average-mass molecular weight from more than 200,000 to 1,000,000 g/mol, density from 0.940 to 0.950 g/cm³ according to ISO 1183, and MFR₂ value from 0.03 to 0.15 g/10 min according to ISO 1133. The first multimodal polyethylene is bimodal or trimodal polyethylene. The second polyethylene is bimodal or trimodal polyethylene. Trimodal polyethylene contains (A) from 30 to 65 wt.% of low-molecular polyethylene characterized by MFR₂ value from 500 to 1000 g/10 min according to ISO 1133 and average-mass molecular weight from 20,000 to 90,000 g/mol, (B) from 5 to 40 wt.% of ultrahigh-molecular polyethylene characterized by average-mass molecular weight from more than 1,000,000 to 5,000,000 g/mol, and (C) from 20 to 60 wt.% of high-molecular polyethylene characterized by average-mass molecular weight from more than 200,000 to 1,000,000 g/mol.

EFFECT: resulting polyethylene composition is characterized by a better balance between resistance to cracking under stress, rigidity, and recyclability compared to known resins.

13 cl, 5 tbl, 4 ex