| 主权项 |
1. A method for increasing the lifetime of a pipe or a fitting made of a polyolefin composition, produced in a sequential multistage process utilizing reactors coupled in series, using a combination consisting of two antioxidants (B) and (C), at least one transition metal, at least one pigment, at least one filler, at least one mineral, and at least on lubricant in said polyolefin composition,
wherein said antioxidants are the following:
antioxidant (B) with general formula R1—P(OAr)2, wherein OAr is according to formula (I): wherein
R1 is a non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms,R2, R3, R4, R5 and R6 independently are a hydrogen atom or non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise heteroatoms, and
antioxidant (C) according to formula (II): wherein
R7, R8 and R9 independently are non-substituted or substituted aliphatic or aromatic hydrocarbyl radicals which may comprise OH-groups,X1, X2, and X3 independently are H or OH, with the proviso that at least one of X1, X2 and X3 is OH, andthe entire molecule does not comprise an ester group; wherein the pipe or fitting is in permanent contact with chlorine dioxide-containing water. |
