Dual-cure acrylic urethane system

Chart 11.5 Part of a three-dimensional network formed by UV irradiation and thermal treatment of a dual-cure acrylic urethane system [27]. 

Blocked isocyanates are particularly helpful in dual cure mechanisms. In one instance, UV light first polymerizes an acrylate polymer containing hydroxyl groups. The system also contains a malonate ester-blocked isocyanate. The one-component system is heated, which starts the polymerization of the acrylate. Higher temperatures unblock the isocyanate, permitting the cure of the urethane to proceed [15]. 

Dual-cure resins for wood composites. These resins (heat and EB irradiation systems) are based on urethane-acrylate thermoplastic adhesive demonstrate efficacy to bond wood. Eow amounfs of EB radiation were needed to produce a wood bond that survived shipping and that improved the composite modulus. The system demonstrated promise and a new direction for wood adhesives. 

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