Primer composition and bonding method

1. A primer composition comprising the following (A), (B), (C), (D), (E) and (F) components:

(A) a saturated hydrocarbon polymer containing at least one alkenyl group per molecule,

(B) a silane coupling agent,

(C) a polyvalent alkoxysilane and/or a condensation product thereof,

(D) an organoaluminum compound and/or an organotitanium compound,

(E) a vinyl copolymer having a backbone structure substantially comprised of a vinyl copolymer chain and containing a silicon-containing group having a hydroxyl or hydrolyzable group bound to a silicon atom and capable of crosslinking by siloxane bonding terminally of its backbone chain and/or in its side chain, and (F) a hydrosilylation catalyst,

wherein substituents on a silicon atom in the polyvalent alkoxysilane as the (C) component consist of at least one group selected from the group consisting of alkyl and alkoxy groups.

2. The primer composition according to claim 1

wherein the (E) component vinyl copolymer has a number average molecular weight in the range of 500 to 50000 and contains a hydrolyzable silyl group of the general formula (1) terminally of its backbone and/or side chain:

wherein R 1 and R 2 each independently represents an alkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms, or a triorganosiloxy group of the formula (R′) 3 SiO—, where R′ groups each independently represents a substituted or unsubstituted hydrocarbon group containing 1 to 20 carbon atoms; X groups each independently represents a hydroxyl group or a hydrolyzable group; a denotes 0, 1, 2 or 3; b denotes 0, 1 or 2; but both a and b are not equal to 0; m denotes an integer of 0 to 19.

3. The primer composition according to claim 1 or 2

wherein the (A) component saturated hydrocarbon polymer is a polyisobutylene polymer having a number average molecular weight in the range of 500 to 50000 and containing at least one alkenyl group terminally of its backbone and/or side chain.

4. The primer composition according to claim 1 or 2

wherein the (B) component silane coupling agent has at least one functional group selected from the group consisting of epoxy, vinyl and (meth)acryloyl groups.

5. The primer composition according to claim 1 or 2 comprising an organic solvent as (G) component.