Preparation and Properties of UV curable urethane methacrylate oligomer

N,N-dihydroxyethyl methylacrylamide (DHEMAA), which is a methacrylate modified by diol, has been prepared by reaction of diethylanol amine with methyl methacrylate. UV curable urethane methacrylate oligomers have been synthesized by the reaction of a series of diol, triol, DHEMAA and HEMA with TDI or IPDI in two reaction orders. The first reaction style is the TDI or IPDI reacted with HEMA first to give methacrylate group ending mono isocyanate, then the mono isocyanate reacted with diol or triol to generated urethane oligomer with two or more functional methacrylate groups. The secondary reaction style is the TDI or IPDI reacted with diol, triol or DHEMAA first to get oligomer, then resulted oligomer reacted with HEMA to obtain the UV curable product with multi-functional groups. The average molecular weight, structure unit of oligomer and number of functional groups could be tuned by adjusting of adding order, ratio of starting materials and the reaction condition. The UV curing properties such as curing rate, hardness of cured film, impact strength, flexibility and so on have been determined. The relationship between the component and the properties of cured film has been discussed.