Rubber-based structural white-shell adhesives
AssigneeHenkel-Teroson GmbH
InventorsPeter Born, Frank Dittrich
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Abstract
One-component hot-curing structural adhesives based on liquid rubbers, which may optionally contain functional groups, solid rubbers, thermoplastic polymer powders and sulfur and also vulcanization accelerators are suitable for bonding metal parts. Tensile shear strengths of more than 15 MPa and high breaking elongations of more than 15% can be obtained. These adhesives are substantially free from low molecular weight epoxy resins and are particularly suitable for use in white-shell assembly in the car industry.
Claims34
A one-component adhesive composition substantially free of epoxy resin and consisting essentially of:
- (a) at least one liquid rubber having a molecular, weight below 20,000 present in an amount of between 5% and 50% by weight,
- (b) at least one thermoplastic polymer powder having an average particle size below 1 mm present in an amount of between 2% and 20% by weight, said thermoplastic polymer powder being selected from the group consisting of vinyl acetate homopolymers, vinyl acetate copolymers, ethylene/vinyl acetate copolymers, vinyl chloride homopolymers, vinyl chloride copolymers, styrene homopolymers, styrene/methacrylic acid copolymer (meth)acrylate homopolymers, (meth)acrylate copolymers, polyvinyl acetals, and mixtures thereof,
- (c) a vulcanization system for said composition comprised of a vulcanizing agent selected from the group consisting of elemental sulfur, thiuram disulfides, organic peroxides, polyfunctional amines, quinones, p-benzoquinone dioxime, p-nitrosobenzene, dinitrosobenzene and mixtures thereof,
- (d) at least one filler present in an amount of between 10% and 70% by weight, all weights being based on the weight of said composition;
- said composition being curable at a temperature of between 80.degree. C. and 240.degree. C., and when cured, having a breaking elongation according to DIN 53504 of more than about 15% and a tensile shear strength of at least 9.4 mPa and forming a permanent adhesive bond to a metal surface.
A one component adhesive composition substantially free of epoxy resin and consisting essentially of:
- (a) at least one liquid rubber having a molecular weight of from 900 to 10,000 present in an amount of between 5% and 50% by weight, said liquid rubber being selected from the group consisting of polybutadienes, polybutenes, polyisobutylenes, polyisoprenes, styrene/butadiene copolymers, butadiene/acrylonitrile copolymers, and mixtures thereof;
- (b) at least one thermoplastic polymer powder having an average particle size below 350 .mu.m present in an amount of between 10% and 15% by weight, said thermoplastic polymer powder being selected from the group consisting of vinyl acetate homopolymers, vinyl acetate copolymers, ethylene/vinyl acetate copolymers, vinyl chloride homopolymers, vinyl chloride copolymers, styrene homopolymers, styrene copolymers, (meth)acrylate homopolymers, (meth)acrylate copolymers, polyvinyl acetals, and mixtures thereof;
- (c) a vulcanization system comprised of 4% to 15% by weight elemental sulfur, 2% to 8% by weight of one or more organic accelerators, and 1% to 10% by weight of one or more zinc compounds;
- (d) at least one filler present in an amount of 25% to 60% by weight;
- (e) at least one stabilizer present in an amount of 0.1% to 5% by weight;
- (f) at least one solid rubber present in an amount of 1.5% to 9% by weight, all weights being based on the weight of said composition;
- said composition being curable at a temperature of between 160.degree. C. and 200.degree. C., and, when cured, having a breaking elongation according to DIN 53504 of more than about 20% and a tensile shear strength of at least 15 mPa and forming a permanent adhesive bond to a metal surface.
Dependencies are inferred from the claim text.