Ciba® IRGASTAB® Cable KV10 in Silane Crosslinked Cable Insulation Compositions
Publication Date: 2003-Jun-02
The IP.com Prior Art Database
Silane crosslinked polyethylene is commonly used for low and medium voltage power cable insulation. Compounds are preferably produced by copolymerization of ethylene and vinylsilanes or by post reactor treatment (grafting) of LDPE with vinylsilane by peroxide. In this so-called Sioplas process a mixture of peroxide and silane is added to polyethylene during compounding, resulting in a silane-grafted polyethylene. Stabilizers and a crosslinking catalyst are added in a second, the form-giving, step. In an alternative technology all components are added in one step (Monosil process). Technically this is very complex but offers significant cost savings to the converter. The simultaneous addition of peroxide and stabilizers can result in negative interactions, which can result in insufficient grafting or inferior compound homogeneity. Additionally, this peroxides always bear the risk of premature crosslinking (scorch). Initial test results have shown that compounds of the formula I according to EP-A-1 249 845 (see claim 2), have a positive impact on the compounding in terms of scorch resistance, process stability and compound homogeneity as well as grafting efficiency. Especially preferred compounds of the formula I are 2,4-bis(n-octylthiomethyl)-6-methylphenol [Ciba® IRGASTAB® Cable KV10; Ciba Specialty Chemicals Inc.] or 2,4-bis(n-dodecylthiomethyl)-6-methylphenol.