Urethane-based adhesive for automobile

A two-liquid type urethane-based adhesive comprises at least:

• a main agent comprising:
• (A) a urethane prepolymer having an isocyanate group at the end thereof;
• (B) an alkoxysilyl group-containing polyfunctional isocyanate compound which is obtained through a reaction of a silane compound having two or more alkoxysilyl groups in one molecule and a polyisocyanate having an isocyanate group at the end thereof, wherein the silane compound having two or more alkoxysilyl groups in one molecule is a bissilylamine compound represented by the following chemical formula 1:
• where:
• each of six R1s is independently an alkyl group having 1 to 3 carbon atoms;
• and
• each of two R2s is independently an alkylene group having 1 to 10 carbon atoms, and
• wherein the polyisocyanate is a polyfunctional isocyanate compound selected from a group consisting of:
• an isocyanurate-type polyfunctional isocyanate being a cyclic trimer of a diisocyanate, wherein the polyisocyanate is represented by the following chemical formula 4:
• where:
• each of three R3s is independently a linear or cyclic alkylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group;
• or an organic group having a phenylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an akoxycarbonyl group or a carboxyl group;
• a biuret-type polyfunctional isocyanate being an adduct of a diisocyanate to a urea group formed of a diisocyanate and an amine, wherein the polyisocyanate is represented by the following chemical formula 5:
• where:
• each of three R4s is independently a linear or cyclic alkylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group;
• or an organic group having a phenylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group;
• an adduct-type polyfunctional isocyanate being an adduct of a diisocyanate to a poly-hydric alcohol, wherein the polyisocyanate is represented by the following chemical formula 6:
• where:
• each of three R5s is independently a linear or cyclic alkylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group;
• or an organic group having a phenylene group which may be substituted by any of an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group, and X is a trivalent hydrocarbon group having 1 to 3 carbon atoms;
• and
• an allophanate-type polyfunctional isocyanate being an adduct of a diisocyanate to a urethane group formed of a diisocyanate and an alcohol, wherein the polyisocyanate is represented by the following chemical formula 7:
• where:
• each of two R6s is independently a linear or cyclic alkylene group which may be substituted with an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group;
• or an organic group having a phenylene group which may be substituted by any of an alkyl group, an alkoxysilyl group, an acyl group, an alkoxycarbonyl group or a carboxyl group, and Y is an alkyl group having 1 to 3 carbon atoms;
• and
• (C1) a first curing catalyst, and
• a curing product comprising
• (D) a hydrophobic polyol and a polyoxyalkylene polyol, and
• (C2) a second curing catalyst.