Adhesives stick with cows and oxygen

Tom Shelley reports on how adhesives can be formulated to meet the needs of some particularly challenging applications

A toughened acrylic adhesive has been specially formulated to allow polyurethane platform shoes to be attached to cow's hooves. Hoof rot distresses cows and reduces their milk yield. Equipping them with temporary feet restores the yield. Peter Kent of Permabond told Eureka that the adhesive had to be especially formulated to set quickly because cows, "Do not stand still for long." Hoof rot affects around a million cows a year across the world. The same company has also recently developed an anaerobic pipe sealant suitable for use with oxygen lines. Most anaerobic sealants are incompatible with oxygen almost by definition. The new formulation, designated MH052, however, once it has set under anaerobic conditions, is proof against oxidation by oxygen. It has been approved by BAM in Germany for conditions up to 10bar pressure and 60 deg C and is currently being used by a US customer to seal oxygen lines for medical equipment. It can also be used to similar applications in aerospace. Other recent developments include transparent and non yellowing ultra violet curable acrylics and clear, colourless epoxies. Toughened acrylics are available for service temperatures to 150 deg C, cyanoacrylates to 200 deg C and anaerobics to 230 deg C. Higher service temperatures are constantly being demanded by the automotive industries for under bonnet service. Permabond