RANDOM PROPYLENE-ETHYLENE POLYMER WITH HIGHLY DISORDERED DISTRIBUTION OF ETHYLENE Russian patent published in 2025 - IPC C08L23/14 C08F210/16 B32B27/32 

FIELD: chemistry.

SUBSTANCE: present invention relates to a single-phase composition (R-PP) of a propylene-ethylene random copolymer for making a film containing: a) from 30 to 70 wt.%, based on total weight of composition (R-PP) of propylene-ethylene random copolymer, first fraction (R-PP1) of the propylene-ethylene random copolymer, having an ethylene content, determined by quantitative ¹³C-NMR spectroscopy, from 0.1 to 5.0 mol.%; b) from 30 to 70 wt.%, based on the total weight of the composition (R-PP) of the propylene-ethylene random copolymer, the second fraction (R-PP2) of the propylene-ethylene random copolymer, having an ethylene content determined by quantitative ¹³C-NMR spectroscopy, from 0.1 to 10.0 mol.%; where the first fraction (R-PP1) of the propylene-ethylene random copolymer and the second fraction (R-PP2) of the propylene-ethylene random copolymer together make at least 95 wt.% of total weight of composition (R-PP) of propylene-ethylene random copolymer, and the propylene-ethylene random copolymer composition optionally contains not more than 5 wt.% additional additives, the ratio of the ethylene content in the propylene-ethylene random copolymer composition (R-PP) to the ethylene content in the first fraction (R-PP1) of the propylene-ethylene random copolymer, both of which are determined by quantitative ¹³C-NMR spectroscopy and are expressed in mol.%, ([C2(R-PP)]/[C2(R-PP1)]) is greater than or equal to 1.00, wherein the (R-PP) propylene-ethylene random copolymer composition has a melting point, determined according to DSC analysis, from 120 to 145 °C, and content of 2,1-regiodefects, determined by quantitative ¹³C-NMR spectroscopy, from 0.05 to 1.40 mol.%, where composition (R-PP) of propylene-ethylene random copolymer has relative content of isolated for blocking ethylene sequences, I(E), greater than or equal to 70.0%, and relative content of isolated for blocking ethylene sequences, I(E), and the content of C2 in the propylene-ethylene random copolymer composition, C2(R-PP), satisfy inequality (I): I(E) - 3.79[C2(R-PP)] ≥ 52.0 (I), where content of I(E) is determined by equation (II): where I(E) is the relative content of isolated for blocking ethylene sequences [in %]; fPEP is the molar fraction of propylene/ethylene/propylene (PEP) sequences in the sample; fPEE is the molar fraction of propylene/ethylene/ethylene (PEE) sequences and ethylene/ethylene/propylene (EEP) sequences in the sample; fEEE is the molar fraction of ethylene/ethylene/ethylene (EEE) sequences in the sample; where all concentrations of sequences are based on statistical analysis of triads from ¹³C-NMR data. Described also is a method of producing said single-phase composition (R-PP) of a propylene-ethylene random copolymer according to any of the preceding claims, involving the following steps: a) polymerising propylene and ethylene comonomer units in a first polymerisation reactor in the presence of a single-site catalyst to obtain a first polymerisation mixture containing a first fraction (R-PP1) of a propylene-ethylene random copolymer and a single-site catalyst, where the first polymerisation reactor is preferably a slurry reactor, more preferably a loop reactor; b) transferring the first polymerisation mixture into a second polymerisation reactor, preferably a gas-phase reactor; c) polymerisation of comonomer links of propylene and ethylene in said second polymerisation reactor in the presence of said single-site catalyst to obtain a second polymerisation mixture containing a first fraction (R-PP1) of a propylene-ethylene random copolymer, a second fraction (R-PP2) of a propylene-ethylene random copolymer and a single-site catalyst; d) unloading said second polymerisation mixture from said second polymerisation reactor and e) compounding said second polymerisation mixture, optionally with addition of additives, to form a single-phase composition (R-PP) of a propylene-ethylene random copolymer. Described is an article, preferably a film, containing said composition.

EFFECT: obtaining an article with improved optical and mechanical properties and welding properties.

15 cl, 1 dwg, 3 tbl, 2 ex