| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition which is cast into a silicone rubber die prepared based on a master model to make it possible to produce a thick-walled duplicate model with high dimensional accuracy and an opaque color and which can give a hard and hardly breakable duplicate model in a short time by forming a composition having a specified ultraviolet transmittance. SOLUTION: This composition has an ultraviolet transmittance at a thickness of 1 mm of 0.05-5%, preferably 0.2-3%. The composition preferably contains an ultraviolet absorber (e.g. benzotriazole based absorber) or at least one inorganic filler selected from CaCO3 , MgCO3 , Mg(OH)2 and MgO. It is desirable to form the composition in such a manner that it contains a polymer having ethylenically unsaturated bonds in the molecule with a molecular weight of 800 to 9,000 (e.g. urethane polymer having terminal methacrylate groups) and an ethylenically unsaturated compound having a molecular weight of less than 800 (e.g. N-methylolacrylamide). |
