摘要:
Provided is an injection moldable composition suitable for forming ceramic or metallic greenbodies. The composition comprises in combination an inorganic or metallic filler in an amount of from about 63 volume percent to about 92 volume percent, a binding organic matrix resin, and an organosilane processing reagent represented by the general formula:SiX.sub.1 X.sub.2 X.sub.3 X.sub.4wherein at least one of X.sub.1, X.sub.2, X.sub.3 or X.sub.4 is an unfunctionalized alkyl or alkenyl group having 10 to 35 carbon atoms and at least one of X.sub.1, X.sub.2, X.sub.3 or X.sub.4 is an alkoxy group or halide, such that the moldable composition exhibits a low initial mixing torque upon mechanical agitation. These compositions offer excellent advantage in processibility using conventional mixing and molding equipment.Also provided is a process for preparing the moldable compositions.
摘要:
A polyacetal binder is removed from an extruded or injection molded ceramic green body in less than 25 hours by a variable heating rate schedule in which the heating rate is reduced when the temperature of the green body reaches the point at which isothermal degradation of the polyacetal binder can take place and wherein at least 80 wt. % of the binder can be removed. In air, the isothermal removal of the binder can take place within the range of 160.degree.-220.degree. C. while in nitrogen the range is from about 300.degree.-360.degree. C.
摘要:
A process for rapidly removing the binder from a greenbody composed of a sinterable powder dispersed within a polyacetal binder is achieved by contacting the molded ceramic greenbody with an acid which depolymerizes the polyacetal binder.
摘要:
Cogranulates of high bulk density which easily disintegrate in water and comprise aluminosilicates and crystalline sodium silicates having a layered structure. The aluminosilicates contained therein are those of the formula M.sub.2/n O.Al.sub.2 O.sub.3. XSiO.sub.2. yH.sub.2 O in which M is an alkali metal or alkaline earth metal, n indicates the valency of the cation, x is.gtoreq.2 and y has a value of between 0 and 8. The sodium silicates have an SiO.sub.2 /Na.sub.2 O ratio of (1.8 to 4.2):1. These cogranulates are prepared by mixing the pulverulent aluminosilicates and sodium silicates with one another and introducing the mixture into a zone in which it is compacted between two rolls rotating in opposite directions to form a compact. After comminution of the compact, the desired particle sizes are finally separated off from the oversize and undersize material. The cogranulates can be used in detergents and cleaning agents.
摘要:
To prepare crystalline sodium silicates having a laminated structure, a molar ratio of SiO.sub.2 to Na.sub.2 O of (1.9 to 2.1) 1 and a water content of less than 0.3% by weight from a water glass solution which has a solids content of at least 20% by weight and is obtained by reaction of sand with sodium hydroxide solution in a molar ratio of SiO.sub.2 : Na.sub.2 O of (2.0 to 2.3) : 1, the water glass solution is treated with hot air of 200.degree. to 300.degree. C. in a spray drying zone to form a pulverulent, amorphous sodium silicate having a water content (determined as the loss on ignition at 700.degree. C.) of 15 to 23% by weight. The pulverulent, amorphous, water-containing sodium silicate is first ground, preferably to particle sizes of 1 to 50 .mu.m, before it is introduced into an inclined rotary tubular oven and treated in this in countercurrent with flue gas at temperatures of more than 500.degree. to 850.degree. C. to form crystalline sodium silicate. The sodium silicate issuing from the rotary tubular oven is first comminuted to particle sizes of 0.1 to 12 mm and finally ground to particle sizes of 2 to 400 .mu.m.