Pregellable adhesives

A process for applying adhesives to vehicles during their construction comprising the steps of

• I) forming a liquid or spreadable vulcanizable rubber mixture based on more than one polymer of which at least one polymer is olefinically unsaturated, wherein said mixture comprises
• (a) from about 30 to about 70 parts by weight of a polymer A containing on average at least two hydroxyl groups per macromolecule;
• (b) from about 70 to about 30 parts by weight of a polymer B compatible with A and containing on average at least two carboxylic acid and/or carboxylic anhydride groups or at least one carboxylic acid and one carboxylic anhydride group per molecule;
• (c) from about 10 to about 120 parts by weight of vulcanization auxiliary components;
• and, optionally,
• (d) from about 0.1 to about 5 parts by weight of an esterification catalyst, wherein at least one of polymers A and B is vulcanizable under vulcanization conditions at an elevated temperature through its olefinic double bonds, and wherein one of polymers A and B is derived from a vulcanizable polydiene and the other polymer is a compatible polyamide, polyester, or a copolymer containing OH and/or carboxylic acid or carboxylic anhydride groups, or wherein both polymers A and B are derived from polydienes or copolymers thereof;
• II) applying the rubber mixture formed in step I) to at least one of two metal vehicle substrates to be bonded together;
• III) placing the vehicle substrates together to form an adhesive bond;
• IV) precuring the adhesive bond at a temperature below the vulcanization temperature of the rubber mixture by means of an esterification reaction to obtain a bond strength that enables the freshly bonded metal vehicle substrates to withstand the mechanical stressing involved in pretreatment of the substrates before painting;
• V) pretreating the metal vehicle substrates wherein the precured adhesive bond is not significantly adversely affected by the pretreating process or processes;
• and
• VI) subsequently bringing the pretreated bonded substrates to a temperature wherein vulcanization of said adhesive bond takes place.