POLYPROPYLENE COMPOSITION WITH IMPROVED HOT-TACK FORCE Russian patent published in 2020 - IPC C09J123/14 C08L23/14 

FIELD: chemistry.

SUBSTANCE: present invention relates to a polypropylene composition used for making heat-sealable films and hot-tack adhesives. Described is a polypropylene composition for producing heat-sealing films and hot-tack adhesives, comprising: a) from 65.0 to 88.0 wt. % of disordered copolymer of crystalline propylene (C-PP) containing monomers of propylene, and from 1.0 to 6.5 wt. % of at least one comonomer selected from ethylene and C₄ -C₁₂ alpha-olefin, with a melting point within 135 to 155 °C, as measured according to ISO 11357-3, and melt flow rate (MFR₂) within 0.1 to 15 g/10 minutes, as measured according to ISO 1133 at temperature of 230 °C and at load of 2.16 kg, and b) from 12.0 to 35.0 wt. % of an amorphous propylene copolymer (AM-PP) containing propylene monomers and 30.0 to 50.0 wt. % of at least one comonomer selected from ethylene and C₄-C₁₂ alpha-olefin and with a glass transition temperature Tg (b); in range from -60 to -40 °C, at that, wt. % of C-PP and AM-PP copolymers are given based on total weight of copolymers of C-PP and AM-PP, wherein said polypropylene composition has melt flow rate (MFR₂) ranging from 0.5 to 25 g/10 minutes, as measured according to ISO 1133 at temperature of 230 °C and at load of 2.16 kg, and also the relative content of the isolated comonomer sequences with respect to block I (E) ranging from 20 to 50 %, as calculated according to the equation: I(E) = fPEP/((fEEE+fPEE+fPEP))×100 (1), where I (E) is the relative content of the isolated comonomer sequences with respect to the block [in %]; fPEP is molar fraction of propylene sequences/comonomer/propylene (PEP) in sample; fPEE is molar fraction of propylene sequences/comonomer/comonomer (PEE) and sequences of comonomer/comonomer/propylene (EEP) in sample; fEEE is a molar fraction of comonomer/comonomer/comonomer (EEE) sequences in sample, where all concentration of sequences is given according to statistically no data analysis on triads obtained using ¹³C-NMR. Invention also describes a method of preparing the composition, use of the polypropylene composition, an article, a film, an adhesive composition, an article containing an adhesive composition, a method of producing the article.

EFFECT: technical result is higher strength of thermos-welded layers connection.

19 cl, 2 tbl