Two-part epoxy adhesives with improved flexibility and process for making and using same

A process of adhering at least two substrate surfaces to each other comprising:

• intercalating between said surfaces an adhesive comprising a reactive mixture of:
• a) a resin component comprising a mixture of epoxy resin, and internally flexible epoxy resin, and
• b) a hardener component consisting essentially of a mixture by weight of:
• 20-80% flexibilizer, wherein said flexibilizer is selected from amine terminated butadiene acrylonitrile adducts or carboxyl terminated butadiene acrylonitrile adducts,
• 5-30% unmodified aliphatic amine, wherein said unmodified aliphatic amine comprises an unmodified glycol ether base aliphatic amine,
• 10-50% modified aliphatic amine, wherein said modified aliphatic amine comprises an AEP base modified amine,
• 0-15% unmodified or modified polyamide,
• 1-10% accelerator, wherein said accelerator is a tertiary amine accelerator, and optionally 5-20% plasticizer/accelerator that acts as both a plasticizer and an accelerator;
• and
• allowing said adhesive to cure,
• wherein said reactive mixture has an initial cure time of less than 3 hours and a complete cure time of approximately 24 hours;
• whereby said cured adhesive has a tensile elongation at room temperature of greater than 30%.

A process for making a two-part epoxy adhesive comprising:

• preparing a resin component by mixing an epoxy resin, an internally flexibilized epoxy resin, a plasticizer/accelerator that acts as both a plasticizer and an accelerator, a coupling agent, fillers, and a thixotropic agent, and
• preparing a hardener component consisting essentially of a mixture by weight of:
• 20-80% flexibilizer,
• 5-45% unmodified aliphatic amine,
• 0-50% modified aliphatic amine,
• 0-15% unmodified or modified polyamide,
• 1-10% accelerator, and
• optionally 15-20% plasticizer/accelerator that acts as both a plasticizer and an accelerator;
• wherein a reactive mixture of said resin component and said hardener component has an initial cure time of less than 3 hours and a complete cure time of approximately 24 hours.

A two-part epoxy adhesive comprising:

• a) a resin component comprising a mixture of epoxy resin, and an internally flexibilized epoxy resin, and
• b) a hardener component consisting essentially of a mixture by weight of:
• 30-80% flexibilizer, wherein said flexibilizer is selected from amine terminated butadiene acrylonitrile adducts or carboxyl terminated butadiene acrylonitrile adducts,
• 5-45% unmodified aliphatic amine, wherein said unmodified aliphatic amine comprises an unmodified glycol ether base aliphatic amine,
• 0-15% modified aliphatic amine, wherein said modified aliphatic amine comprises an AEP base modified amine,
• 0-15% unmodified or modified polyamide,
• 1-10% accelerator, wherein said accelerator is a tertiary amine accelerator, and
• optionally 5-20% plasticizer/accelerator that acts as both a plasticizer and an accelerator;
• wherein a reactive mixture of said resin component and said hardener component has an initial cure time of less than 3 hours and a complete cure time of approximately 24 hours;
• and
• wherein after said resin component and said hardener component are mixed and reacted the cured epoxy adhesive has a tensile elongation at room temperature of greater than 30%, and wherein said resin component is free of nonylphenol and said hardener component is free of nonylphenol.

A process of adhering at least two substrate surfaces to each other comprising:

• intercalating between said surfaces an adhesive comprising a reactive mixture of:
• a) a resin component comprising a mixture of epoxy resin, and internally flexible epoxy resin, and
• b) a hardener component consisting essentially of a mixture by weight of:
• 30-80% flexibilizer, wherein said flexibilizer is selected from amine terminated butadiene acrylonitrile adducts or carboxyl terminated butadiene acrylonitrile adducts,
• 5-45% unmodified aliphatic amine, wherein said unmodified aliphatic amine comprises an unmodified glycol ether base aliphatic amine,
• 0-15% modified aliphatic amine, wherein said modified aliphatic amine comprises an AEP base modified amine,
• 0-15% unmodified or modified polyamide,
• 1-10% accelerator, wherein said accelerator is a tertiary amine accelerator, and
• optionally 5-20% plasticizer/accelerator that acts as both a plasticizer and an accelerator;
• and
• allowing said adhesive to cure,
• wherein said reactive mixture has an initial cure time of less than 3 hours and a complete cure time of approximately 24 hours;
• whereby said cured adhesive has a tensile elongation at room temperature of greater than 30%, and
• wherein said resin component is free of nonylphenol and said hardener component is free of nonylphenol.