Amorphous and crystalline urethane acrylates are mixed in a ratio of amorphous to crystalline of 60:40 to 90:10% by weight, so that the end product has a Tg of at least 35??? C. The mixing ratio of amorphous to crystalline urethane acrylate includes all values and subvalues therebetween, especially including 65:35, 70:30, 75:25 and 80:20% by weight.