| 摘要 |
PURPOSE:To obtain the title material which is lowly water-absorptive and provides an optical element having excellent optical performance, heat resistance and dimensional stability in moisture, by copolymerizing methyl methacrylate, a specified N-substd. maleimide monomer and a hydrophobic monomer other than aromatic vinyl compounds. CONSTITUTION:2-54wt.% methyl methacrylate A, 2-80wt.% N-substd. maleimide B (e.g. N-cyclohexylmaleimide) of formula I (where R is H or a 1-15C alkyl or cyclic alkyl) and 15-96wt.% hydrophobic monomer C, other than aromatic vinyl monomes, of formula II (where R is H, CH3 or a halogen; R' is a 4-15C alkyl or cyclic alkyl, and when R is a halogen, R' is a 1-15C alkyl or alicyclic alkyl) which is selected from among monomers which provide a homopolymer whose water absorption is 0.25% or below in a 24hr immersion test according to ASTM D570, are polymerized in the presence of a radical polymn. initiator to give the title material consisting of a copolymer having an intrinsic viscosity of 0.15-0.50 (in methyl ethyl ketone at 30 deg.C) and an MI of 2-70g/10min (glass transition point plus 100 deg.C).
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