Patent GB-572679-A (GB)
Title: Abrasive articles and methods of making the same
IPC: C08L75/04
Filed: 1943-09-25
Abstract: A bonded abrasive article, particularly a grinding-wheel, is made by coagulating an acrylic nitrile-butadiene latex in the presence of abrasive grains and a vulcanizing agent by means of a compound of an alkali metal, and vulcanizing the mass obtained in the desired shape by heat.  The coagulating-agent may be sodium hydroxide, sodium or potassium chloride or carbonate, or sodium acetate or crotanate.  The abrasive, e.g. crystalline alumina or silicon carbide is mixed dry with sulphur, and to the mixture is added the latex and an aqueous solution of the coagulating agent, the mass is stirred and spread out to dry at room temperature to form a friable cake which is screened and dried further at 105 DEG  C.; alternatively, the mass may be pressed in a mould to remove water and then vulcanized.  A wetting-agent or plasticizer such as furfural, tricresyl phosphate, phenol-formaldehyde condensation product in the liquid stage, or triglycol dichloride, fillers, e.g. clay, cryolite, or cured resin powders and additional bonding-agents which will cure at the vulcanizing temperature, e.g. phenolformaldehyde, aniline-formaldehyde, resorcinolformaldehyde, or methyl-methacrylate resins, or mixtures of methyl methacrylate and methacrylic anhydride or acid may be added.  Specification 563,556 is referred to.ALSO:A bonded abrasive article, particularly a grinding-wheel, is made by coagulating an acrylic nitrile-butadiene latex in the presence of abrasive grains and a vulcanizing-agent by means of a compound of an alkali metal, and vulcanizing the mass obtained in the desired shape. The coagulating - agent, preferably sodium hydroxide, although sodium or potassium chloride or carbonate, or sodium acetate or crotonate may be used, is present in sufficient amount to coagulate substantially all of the synthetic rubber, which is present in an amount equal to at least 30 per cent, and preferably over 40 per cent of the latex.  The abrasive, e.g. crystalline alumina or silicon carbide, is mixed dry with sulphur, and to the mixture is added the latex and an aqueous solution of the coagulating agent, the mass is stirred and spread out to dry at room temperature to form a friable cake which is screened and dried further at 105 DEG  C.; alternatively, the mass may be pressed in a mould to remove water and then vulcanized.  To provide better adhesion between the rubber and abrasive, a wetting-agent or plasticizer such as furfural, tricresyl phosphate, phenol-formaldehyde condensation product in the liquid stage, or triglycol dichloride may be added.  Inorganic or inert organic fillers, e.g. clay, cryolite, or cured resin powders, and additional bonding-agents which will cure at the vulcanizing temperature, e.g. phenol - formaldehyde, aniline formaldehyde, resorcinol - formaldehyde, or methyl - methacrylate resins, or mixtures of methyl methacrylate and methacrylic anhydride or acid may be added.  Curing may be effected by heating in the mould at 165 DEG C. for several hours, or after heating in the mould for 15 minutes at 165 DEG  C., heating in an open condition in an oven. Specification 563,556 is referred to.