PIPES MANUFACTURED FROM POLYETHYLENE COPOLYMER WITH SLOW CRACK GROWTH Russian patent published in 2015 - IPC C08L23/04 C08L23/08 C08K5/13 C08K5/134 F16L9/12 

FIELD: chemistry.

SUBSTANCE: invention relates to pipe, possessing increased resistance to growth of pipe cracks and manufactured from polyethylene composition, as well as to application of phenol type stabiliser (C) and phenol type stabiliser (D) to increase resistance of pipes to slow crack growth. Pipe consists of polyethylene composition, which includes basic resin and phenol type stabilisers (C) and (D), which are different. Stabiliser (C) contains, at least, one ester group, and stabiliser (D) does not contain any ester group. Basic resin of polyethylene composition contains first ethylene homo- or copolymer (A) and second ethylene copolymer (B), with comonomer(s) for copolymer (B) and, possibly, copolymer (A) representing C₃-C₂₀ alpha-olefins.

EFFECT: pipes in accordance with invention have stability in testing whole cut for creep (FNCT), measured in accordance with ISO 16770:2004, at least, 5000 h.

11 cl, 1 tbl, 3 ex