FIELD: polymer production.
SUBSTANCE: invention relates to a polymer composition for molding and a container capping means containing such a polymer composition. The composition contains ethylene homopolymer and ethylene copolymer containing comonomer, which is 1-butene, in the amount from 0.60 to 0.65 mol.% relatively to the total amount of monomer in ethylene copolymer. Ethylene copolymer has higher average molecular weight than ethylene homopolymer, wherein the polymer composition has the density in the range of 0.9553-0.9560 g/cm3, the flow rate of MFR2 melt from 0.72 to 0.78 g/10 min under test conditions at 190°C with a load of 2.16 kg, the average molecular weight from 150,000 to 200,000 g/mol, the viscosity at an angular frequency of 0.01 [1/s], η0.01 at 190°C from 22371 to 24420 Pa*s. The mass ratio of ethylene homopolymer to ethylene copolymer in the polymer composition is in the range from 45:55 to 55:45. The polymer composition has a half-period of isothermal crystallization, which is from 2 to 9 min at 123°C and a creep test value with a full incision at a constant load of 5.78 MPa at 50°C from 60 to 81 h. A container capping means and the use of a container capping means as a lid for a bottle or beverage are also described.
EFFECT: providing a polymer composition that is resistant to cracking under the influence of high voltage with a good balance of the crystallization rate to achieve resistance to cracking under the influence of high voltage and fast cycle time, as well as good fluidity during injection.
8 cl, 3 tbl, 5 ex
