DEVELOPMENTS IN POLYMERISATION INITIATORS, POLYMERISABLE COMPOSITIONS, AND USES THEREOF FOR BONDING LOW SURFACE ENERGY SUBSTRATES

摘要

Metal alkyl borohydrides are used as initiators of polymerisation, particularly in adhesive compositions for bonding a wide range of substrates including low surface energy substrates such as polyolefins. As described, the metal alkyl borohydrides are of the formula I    whereinR¹ is C₁ - C₁₀ alkyl,R², R³ and R⁴, which may be the same or different, are H, D, C₁ - C₁₀ alkyl or C₁ - C₁₀ cycloalkyl, phenyl, or phenyl-substituted C₁ - C₁₀ alkyl or C₁ - C₁₀ cycloalkyl, provided that any two of R¹ - R⁴ may optionally be part of a carbocyclic ring, and    M+ is a metal ion.;In particular, alkali metal trialkyl borohydrides are used, the alkali metal salt being selected from the group consisting of: Lithium triethylborohydride, Sodium triethylborohydride, Potassium triethylborohydride, Lithium tri-sec-butylborohydride, Sodium tri-sec-butylborohydride, Potassium tri-sec-butylborohydride, Lithium 9-borabicyclo [3.3.1]-nonane (9BBN) hydride, Lithium thexylborohydride, Lithium trisiamylborohydride, Potassium trisiamylborohydride and Lithium triethylborodeuteride.;A polymerisable composition, particularly a two part adhesive composition. comprises:a) a free-radically polymerisable monomer component, andb) an effective amount of an initiator system for initiating polymerisation of the free-radically polymerisable monomer, said initiator system comprising a metal alkyl borohydride.