A structural epoxy adhesive is playing a critical role in the fast assembly of durable glass reinforced plastic (GRP) sandwich construction wall systems at Norway''s Marine Composites AS. The self-supporting walls are used in the manufacture of hygienic hospitals and buildings used by food processing, electronic, and pharmaceutical industries. Araldite 2015 epoxy, supplied by the Adhesives & Tooling Division of Vantico, in Duxford, England, was selected for the project because of its ease of handling and performance characteristics, including the ability to produce resilient bondlines that can withstand exposure to corrosive marine environments as well as temperature extremes.
"We chose Araldite 2015 for its particularly good adhesion to GRP and because of its gap-filling capacity," says Jon Inge Brattekas, managing director of Marine Composites AS. "Also, many locations in Norway are exposed to the elements and Araldite 2015 has a very high resistance to seawater and can withstand ambient temperatures which can vary between -40° and 95°F."
Marine Composites AS wall systems are comprised of individual modules of various sizes that are assembled like LEGO toy blocks to form buildings. Technicians begin each wall section by degreasing and lightly abrading surfaces to be bonded. Next, Araldite 2015 resin and hardener are mixed and applied to the pretreated area in a 0.002 to 0.004 inch thick layer. This thickness imparts the greatest lap shear strength to lap-joints used in the wall assembly. Components are then clamped together and placed in an oven for 50 minutes at 140°F until fully cured. Vantico''s Araldite 2015 adhesive facilitates the bonding process because it resists sagging up to a 0.4 inch thickness.