Process for the production of methacrylic resin sheets
US5151482A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 1991 |
| Grant date | Sep 29, 1992 |
| Priority date | — |
| Expiry date | Aug 12, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2333/12
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A monomer comprising methyl methacrylate either alone or in combination with another acrylic or methacrylic ester monomer is partially polymerized to prepare a syrup, to which an initiator including a peroxide having a 10-hour half-life temperature of 50.degree. to 58.degree. C. and 2,2'-azobisisobutyronitrile are added. The resulting syrup, after being poured into a mold, is initially polymerized in a first step at a temperature of 75.degree. to 90.degree. C. for a period of 5 to 15 minutes, then further polymerized in a second step at a temperature 3.degree. to 12.degree. C. lower than the temperature of the first step polymerization until a conversion of monomer to polymer of 80 to 95% is attained. The polymerization product which is now in the form of a sheet is then heat-treated at a temperature of 95.degree. to 140.degree. C. to obtain a methacrylic resin sheet. According to this process, methacrylic resin sheets having little residual monomer and being substantially free of defects can be manufactured with high productivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.