Abstract: A melamine polymetaphosphate having a solubility of from 0.01 to 0.10 g/100 ml in water at 25.degree. C., a pH of from 2.5 to 4.5 in the form of a 10 wt % aqueous slurry at 25.degree. C. and a melamine content of from 1.0 to 1.1 mol per mol of phosphorus atom.A process for producing such a melamine polymetaphosphate, which comprises the following steps (a) and (b):(a) a step of mixing melamine, urea and an aqueous orthophosphoric acid solution containing at least 40 wt % of orthophosphoric acid, in such a ratio that melamine is from 1.0 to 1.5 mol per mol of orthophosphoric acid and urea is from 0.1 to 1.5 mol per mol of orthophosphoric acid, at a temperature of from 0 to 140.degree. C., to form a reaction mixture, and stirring the reaction mixture at a temperature of from 0 to 140.degree. C., while removing water, to obtain a powdery product of a double salt of orthophosphoric acid with melamine and urea; and(b) a step of calcining the powdery product obtained in step (a) at a temperature of from 240 to 340.

Abstract: A semiconductor integrated circuit device with a copy-preventive function comprises a memory for storing data to be used by users, an input unit for performing various logical operations on at least one input information fed externally and accessing the memory, an output unit for performing various logical operations on the data at the time of supplying the data from the memory, a judging unit for comparing at least one of the state of the input information, the logical state of the input unit, the logical state of the output unit, and the state of data provided by the output unit with specific judgment information and indicating the result of comparison, and a control unit that when the result indicated by the judging unit reveals that the at least one of the states is consistent with a specific state, acts at least on the output unit so as to prevent data stored in the memory from being supplied normally.

Abstract: A melamine cyanurate powder composed of readily dispersible aggregated primary particles of melamine cyanurate surface-treated with a metal oxide.

Abstract: The present invention provides a power flame retardant for a halogen-containing vinyl resin, which comprises the following Components A, B and C. (A) 5 to 30 parts by weight of at least one of alkali metal compound of lithium, sodium and potassium calculated as the formula M.sub.2 O where M is an alkali metal; (B) 0.2 to 10 parts by weight of a perchloric acid radical in the form of the acid or a salt or amine thereof, calculated as perchloric acid radical; and (C) 1 to 50 parts by weight of a hydrophobic dispersing agent having a boiling point or a decomposition temperature of 200.degree. C. or higher. All the parts by weight are based on 100 parts by weight of antimony pentoxide (Sb.sub.2 O.sub.5). The flame retardant of the present invention does not impair transparency of the halogen-containing vinyl resin, and also does not worsen various physical properties such as thermal stability and weathering resistance.

Abstract: Disclosed is a method of producing porous vitrified grinder, where melamine cyanurate is used as a pore-imparting agent. The grinder has a long life and has an improved grinding capacity.