Internally blocked organoborate initiators and adhesives therefrom

A method for adhesively bonding substrates, the method comprising the steps of:

• (a) providing at least a first and a second substrate;
• (b) applying a mixture to at least one of said first and said second substrates, said mixture comprising:
• (i) at least one addition polymerizable component;
• (ii) an effective amount of an internally blocked borate compound having a ring structure (II) or (II′)
• wherein X represents —CHR7—, oxygen or sulfur;
• n is the integer 1, 2, 3, 4, or 5, and R1, R2, R3, R4, R5, R6 and R7 are independently selected from unsubstituted and substituted alkyl or alkylene groups containing 1 to 10 carbon atoms, substituted aryl groups having up to 7 to 12 carbon atoms, and unsubstituted aryl groups;
• alternatively either of R3, R4, R5, R6 and R7 are hydrogen;
• R1 and R2 alternatively are part of a second unsubstituted or substituted cyclic borate;
• R1 and R2 alternatively comprise a spiro ring or a spiro-ether ring;
• R1 or R2 together with R3 or R4 alternatively are linked to form a cycloaliphatic ring;
• and R1 or R2 together with either R3 or R4 alternatively comprise a cyclic ether ring;
• and M is any positively charged species with charge m greater than 0 and
• (iii) a deblocking agent;
• (c) mating the first and second substrates with said mixture of step (b) therebetween;
• and
• (d) allowing the at least one addition polymerizable component to polymerize, optionally with application of heat, whereby the first and second substrates are adhesively bonding.