The use of tiny diamonds for finish polishing of glass lenses has been made possible by incorporating them into a lap material comprising very small diamonds in a special polymeric matrix of the reaction product of an organic epoxide with an appropriate "hardener," such as a polyamine.
The use of an aromatic amine salt of a substituted pentafluoroantimonic acid as a curing agent for epoxy resins, and the use of the epoxy resin compositions as binders for abrasives in abrasive sheet products, are disclosed. The aromatic amines are selected from aniline and hindered aromatic amines.
An improved article for preparing critical surfaces, in particular for polishing, comprises means including a surface carrying a polishing abrasive of an average particle size less than 10 microns carried on a polymer matrix which has at least one of the following properties, microporosity, hydrophilicity and weak bonding to the polishing abrasive.
According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 .mu.m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce.sup.3+) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95.degree. C. and at an atmospheric pressure.
A process for manufacturing an abrasive tape comprising the steps of preparing a coating solution by mixing, as main constituents, abrasive grains, a binder, and a solvent, applying this coating solution on a substrate and drying the coating, and curing the binder, wherein the binder used in preparation of the tape as its essential components either: I. (a) a polymer having repeating units of the formula ##STR1## and having a number average molecular weight of 1,000 to 5,000 (b) a polyester resin containing in its molecule a condensate of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and an aliphatic diol and having a number average molecular weight of 10,000 to 30,000 terminal OH groups and a glass transition point (Tg) of -20.degree. C. to 40.degree. C., and (c) a polyfunctional isocyanate II. (a) a polymer having repeating units of the formula ##STR2## (b) a polyurethane resin having a number average molecular weight between 5,000 and 20,000 and terminal OH groups, and (c) a polyfunctional isocyanate. (d) the component II (a) to II (b) ratio by weight being in the range 10:90 to 40:60.
A method is provided whereby articles of manufacture, such as tools suitable for use in lens grinding and finishing operations, can be cast with an aluminum filled epoxy composition. The resultant articles are relatively inexpensive and light in weight, and they exhibit the levels of dimensional stability, durability, hardness, and machineability necessary to render them highly suited for their intended purposes.
