Polymerisation initiators based on ammonium tetraalkyl boranes, polymerisable compositions, and uses thereof for bonding low surface energy substrates

摘要

Quaternary boron salts are used as initiators of polymerisation in adhesive compositions for bonding low surface energy substrates such as polyolefins. The quaternary boron salts are of the formula I wherein R¹ is C₁-C₁₀ alkyl, R², R³ and R⁴, which may be the same or different, are, C₁-C₁₀ alkyl or C₃-C₁₀ cycloalkyl, phenyl, or phenyl-substituted C₁-C₁₀ alkyl or C₃-C₁₀ cycloalkyl, provided that any two of R¹-R⁴ may optionally be part of a carbocyclic ring, and M⁺ is a metal ion or a quaternary ammonium ion. When M⁺ is a quaternary ammonium ion, the initiator may be used in a two-part composition having a (meth)acrylate monomer in both parts and the initiator compound in one part, the two parts being in a weight ratio of about 1:1. Particular examples of initiator compounds include sodium tetraethyl borate, lithium tetraethyl borate, lithium phenyl triethyl borate, tetramethylammonium phenyl triethyl borate, and tetra methyl ammonium phenyl tri-n-butyl borate, the last-mentioned of which is a novel compound.