| 摘要 |
1,142,772. Ceramic articles. DOW CORNING CORP. 20 June, 1967 [18 July, 1966], No. 28391/67. Heading C1J. Articles are formed from a mixture of (1) a resinous organopolysiloxane block copolymer consisting essentially of (a) polymer blocks of average general formula in which the sum of x+y+z has an average value of 6 to 100, and y and z each have a value up to 10% of the sum of x, y and z; (b) polymer blocks of average general formula in which R, if present, is an alkyl or alkenyl radical containing less than 6 carbon atoms, q has an average value of 1À0-1À3 and w has an average value of up to 0À3, the siloxane units in (a) being from 10-75 mol. per cent and the siloxane units in (b) being from 25-90 mol. per cent of the total siloxane units in the block copolymer, the minimum amount of (b) when the sum x+y+z is from 50 to 100 being determined by the equation where M is the minimum amount of (b) in mol. per cent and S is x+y+z, with (2) from 10- 60% by volume of a ceramic material based on the total volume of (1) and (2) having a softening point above 800‹ C. and free from materials which volatilize below 800‹ C.; the formed article is heated to 50-300‹ C. whereby it is altered in dimension and ceramified by further heating to 500-1550‹ C. The ceramic material (2) may be aluminium silicate, magnesium silicate, ZnO, MgO, Fe 2 O 3 , Al 2 O 3 , ZrO 2 , tungsten carbide, titanium carbide, molybdenum carbide, lithium aluminate, silicon nitride, boron nitride, zinc silicate, calcium aluminium silicate, magnesium aluminium silicate or lithium aluminium silicate. |
