Adhesive composition

A laminate comprising two substrates adhered together with a heat cured adhesive, said adhesive prior to curing comprising a polyurethane and polyurea resin system, a catalyst, optionally one or more fillers and optionally a pigment and/or dye,

• wherein said resin system comprises a prepolymer and a curative composition, said prepolymer being a urethane prepolymer having terminal free --NCO groups, said curative composition comprising one or more polyamines and one or more polyols capable of forming a cross linked polyurethane,
• wherein the isocyanate index (--NCO/(--OH+--NH)) of said resin system is from 1.20 to 2 and wherein said one or more polyamines consist essentially of one or more aromatic polyamines, said one or more aromatic polyamines being
• (a) one or more primary aromatic polyamines having the formula ##STR3## where R.sub.1 is ##STR4## or the same as any of R.sub.2 through R.sub.6 and where the R.sub.2 through R.sub.6 and R.sub.7 through R.sub.11 are independently selected from the groups of:
• H;
• NH.sub.2 ;
• C.sub.1 to C.sub.5 alkyl;
• or phenyl;
• wherein A is an alkylene hydrocarbon containing 0 to 12 carbons and each molecule contains at least 2 NH.sub.2 groups, when R.sub.1 is not Formula II, at least 4 of the R.sub.1 through R.sub.6 groups are not H, and Formula I is not diethyl toluene diamine, and where R.sub.1 is Formula II and A is 1 to 12 carbon atoms at least 4 of the R.sub.2 through R.sub.11 groups are not H or
• (b) one or more primary aromatic polyamines with fused polycyclic aromatic rings having at least 2 NH.sub.2 groups per molecule, and having H, NH.sub.2, C.sub.1 to C.sub.5 alkyl, or phenyl groups attached to the ring carbons which are not bridge-head carbons or combinations thereof.

A process for adhesively joining two or more substrates individually selected from fiberglass reinforced plastic, metal, and plastic free of a surface primer, the process comprising;

• mixing a urethane prepolymer having unreacted isocyanate terminal groups with a curative component forming a urethane adhesive, wherein said curative component comprises one or more polyols and one or more polyamines having primary amine groups;
• wherein all said primary amines consist essentially of aromatic primary amines;
• applying said urethane adhesive to the two or more substrates;
• thickening said urethane adhesive by forming homogeneously dispersed urea linkages from the isocyanate terminal groups and said one or more aromatic primary polyamines;
• and
• heating said urethane adhesive to a temperature above 50.degree. C. to cure said urethane adhesive and bond said two or more substrates;
• said one or more primary polyamines being used in amounts from 0.5 to 3 parts by wt. per 100 parts by wt. of said curative component and they consist essentially of
• (a) one or more primary aromatic polyamines having the formula ##STR5## where R.sub.1 is ##STR6## or the same as any of R.sub.2 through R.sub.6 and where the R.sub.2 through R.sub.6 and R.sub.7 through R.sub.11 are independently selected from the groups of:
• H;
• NH.sub.2 ;
• C.sub.1 to C.sub.5 alkyl;
• or phenyl, A is an alkylene hydrocarbon containing 0 to 12 carbons and each molecule contains at least 2 NH.sub.2 groups, where R.sub.1 is not Formula II, at least 4 of the R.sub.1 through R.sub.6 groups are not H, and Formula I is not diethyl toluene diamine, and where R.sub.1 is Formula II and A is 1 at least 4 of the R.sub.2 through R.sub.11 groups are not H, or
• (b) one or more primary aromatic polyamines with fused polycyclic aromatic rings having at least 2 NH.sub.2 groups per molecule, and having H, NH.sub.2, C.sub.1 to C.sub.5 alkyl, or phenyl groups attached to the ring carbons which are not bridge-head carbons, or combinations thereof, and wherein said thickening occurs in 3 seconds or less after said mixing process.