Mouldings of polycarbonates with improved surfaces and process for their production
Abstract
Abstract Shaped articles of high molecular weight thermoplastic polycarbonates having improved ultraviolet resistance have an ultraviolet absorber in an amount of from about 3 to about 30 grams per square meter dispersed to a depth of 5 to about 30 Mu from the surface, which is sealed, may be prepared, for example, by applying to the surface about 150 to about 300 cc./sq./m. of a solution containing from about 2.5 to about 10 percent by weight of an ultraviolet absorber in a mixture of one part by weight of 1,2-dichloropropane and about 1 to about 25 parts by weight of benzene or in a mixture of about 80 to about 20 percent by weight 1,2-dichloroethane or 1,2-dichloropropane and about 20 to about 80 percent by weight 1,1,2-trifluoro-1,2,2-trichloroethane or 1,1,2,2-tetrachloro-difluoroethane and then removing the solvent.
Inventors
- 👤 Gunter Peilstocker
Bibliographic Details
Claims Analysis
Total Claims: 3References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |