Claims
- 1. A methacrylic copolymer having low moisture absorption properties, comprising (A) 2 to 30% by mole of tertbutylcyclohexyl methacrylate units, (B) 60 to 98% by mole of methyl methacrylate units and (C) 0 to 30% by mole of ethylenically unsaturated compound units represented by formula (1): ##STR5## wherein R.sub.1 is a hydrogen atom or a methyl group and R.sub.2 is a phenyl group, a methyl-substituted phenyl group or ##STR6## wherein Z is an alkyl group having 1 to 8 carbon atoms, which is unsubstituted or substituted with a fluorine atom, the total of (A), (B) and (C) being 100% by mole, and the copolymer having a weight average molecular weight in the range of from 10.sup.4 to 10.sup.7.
- 2. The methacrylic copolymer having low moisture absorption properties according to claim 1, wherein the proportion of ethylenically unsaturated compound units (C) is 1 to 10% by mole and wherein R.sub.1 in formula (1) is H and R.sub.2 in formula (1) is ##STR7## wherein Z is an alkyl group having 1 to 8 carbon atoms.
- 3. The methacrylic copolymer having low moisture absorption properties according to claim 1, wherein the proportion of ethylenically unsaturated compound units (C) is 5 to 30% by mole and wherein R.sub.2 in formula (1) is a phenyl group or a methyl-substituted phenyl group.
- 4. The methacrylic copolymer having low moisture absorption properties according to any one of claims 1 to 3, wherein said copolymer is in the form of a shaped article.
- 5. The methacrylic copolymer having low moisture absorption properties according to claim 4, wherein said shaped article is an injection-molded article.
- 6. The methacrylic copolymer having low moisture absorption properties according to claim 5, wherein said injection-molded article is an optical element substrate.
- 7. The methacrylic copolymer having low moisture absorption properties according to claim 6, wherein said optical element substrate is an optical disc substrate.
- 8. The methacrylic copolymer having low moisture absorption properties according to claim 5, wherein said copolymer has a weight average molecular weight in the range of from 10.sup.4 to 2.times.10.sup.5.
- 9. The methacrylic copolymer having low moisture absorption properties according to claim 8, wherein said copolymer has a weight average molecular weight in the range of from 5.times.10.sup.4 to 1.5.times.10.sup.5.
- 10. The methacrylic copolymer having low moisture absorption properties according to claim 4, wherein said shaped article is an extruded article.
- 11. The methacrylic copolymer having low moisture absorption properties according to claim 10, wherein said extruded article is a light transmissible extruded plate.
- 12. The methacrylic copolymer having low moisture absorption properties according to claim 10, wherein said copolymer has a weight average molecular weight in the range of from 10.sup.5 to 3.times.10.sup.5.
- 13. The methacrylic copolymer having low moisture absorption properties according to claim 12, wherein said copolymer has a weight average molecular weight in the range of from 1.5.times.10.sup.5 to 2.5.times.10.sup.5.
- 14. The methacrylic copolymer having low moisture absorption properties according to claim 4, wherein said shaped article is a light transmissible plate obtained by cast method.
- 15. The methacrylic copolymer having low moisture absorption properties according to claim 6, wherein said copolymer has a weight average molecular weight in the range of from 10.sup.4 to 2.times.10.sup.5.
- 16. The methacrylic copolymer having low moisture absorption properties according to claim 7, wherein said copolymer has a weight average molecular weight in the range of from 10.sup.4 to 2.times.10.sup.5.
- 17. The methacrylic copolymer having low moisture absorption properties according to claim 11, wherein said copolymer has a weight average molecular weight in the range of from 10.sup.5 to 3.times.10.sup.5.
Parent Case Info
This application is a continuation of application Ser. No. 246,823, filed July 26, 1988, PCT JP 88/00099 on Jan. 7, 1988, now abandoned.
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Continuations (1)
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Number |
Date |
Country |
Parent |
246823 |
Jul 1988 |
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