| 摘要 |
1,131,415. Treated mica. GENERAL ELECTRIC CO. 30 Nov., 1965 [2 Dec., 1964], No. 50797/65. Heading C1A. [Also in Divisions B5, D2 and H1] A mica sheet which is free of all potentially water producing hydroxyl groups to an extent such that it shows at most 0À1% weight change after heating to 800-1000‹ C. may be prepared by reconstituting exfoliated mica as a sheet using normal paper making methods and then heating the sheet until it has the desired properties. Suggested heating regimes are 850‹ C. for 1 hour, 790‹ C. for 2 hours or 650‹ C. for 18 hours but no definite combination of time and temperature is claimed. If desired the sheet may be impregnated with an inorganic binder before the heating step or with an organic or an inorganic binder after the heating step. Suitable binding materials specified are solutions of ammonium or potassium diborate and ammonium or potassium dihydrogen phosphate. Several impregnated sheets may be laminated by the use of suitable heat and pressure conditions. The flexural strength and electrical properties of the product are indicated in the examples. The product finds use as a circuit board piece or a spacer means in an electronic tube. |
