Patent GB-347577-A (GB)
Title: Improvements in or relating to bonded articles embodying synthetic resins
IPC: C08K3/00
Filed: 1929-11-20
Abstract: Ester condensation products.-A mouldable composition comprising a filler (for example, abrasive grains) and a binder containing an alkyd resin in intimate mixture is characterized in that the alkyd resin is in that stage of condensation obtained when the molten preliminary condensation product is at the point of incipient gelation, that is, as near as possible to the point at which there is a rapid transformation into the infusible condition, and at this point the mass is cooled before such transformation can take place by pouring it into a mould or vessel.  Alternatively, the alkyd resin may be this preliminary condensation product subjected to further heating.  A test for this point of incipient gelation is when the mass is sufficiently viscous to be drawn into a string when a rod is dipped into the mass.  The fusible product is then converted into the infusible form by subsequent heating.  The composition is particularly adapted for making grinding wheels.  According to the example, two parts by weight and one of glycerol are boiled together and the mixture heated until the water of reaction is eliminated, the heating being continued at a temperature ranging from 140 DEG  C. to 200 DEG  C. or even as high as 230-235 DEG  C., to the point of incipient gelation.  The product is then poured into a mould or vessel and baked at 140-200 DEG  C. for one to four hours or more. The reactive product is cooled, finely ground, and mixed with the filler.  When abrasive fillers are used it is preferred to add all or part of the filler to the roughly ground or broken resinoid before grinding in a ball mill.  The proportion of resinoid may vary from 5 to 20 per cent; for grinding wheels a proportion of 1 part of resinoid to 7 parts by weight of abrasive is referred to.  For cold moulding a solvent such as a glycol ether, with or without a non-solvent such as kerosene or creosote oil, is preferred.  The use of chlorinated naphthalenes and of solutions of the glycerol resinoid is also referred to, and a lubricant such as calcium stearate may be used.  Heat may be applied to the mould, but preferably the moulded articles are baked in an oven.  Other resinoids, such as phenolic resins, may be components of the composition, and the alkyd resinoids may be other than glycerol alkyd resinoids.ALSO:A mouldable composition comprising a filler (for example, abrasive grams) and a binder containing an alkyd resin in intimate mixture is characterized in that the alkyd resin is in that stage of condensation obtained when the molten preliminary condensation product is at the point of incipient gelation, that is, as near as possible to the point at which there is a rapid transformation into the infusible condition, and at this point the mass is cooled before such transformation can take place by pouring it into a mould or vessel.  Alternatively, the alkyd resin may be this preliminary condensation product subjected to further heating.  A test for this point of incipient gelation is when the mass is sufficiently viscous to be drawn into a string when a rod is dipped into the mass.  The fusible product is then converted into the infusible form by subsequent heating.  The composition is particularly adapted for making grinding wheels.  According to the Example, two parts by weight and one of glycerol are boiled together and the mixture heated until the water of reaction is eliminated, the heating being continued at a temperature ranging from 140 DEG  C. to 200 DEG  C. or even as high as 230-235 DEG  C., to the point of incipient gelation.  The product is then poured into a mould or vessel and baked at 140-200 DEG  C. for one to four hours or more. The reactive product is cooled, finely ground, and mixed with the filler.  When abrasive fillers are used it is preferred to add all or part of the filler to the roughly ground or broken resinoid before grinding in a ball mill.  The proportion of resinoid may vary from 5 to 20 per cent.; for grinding wheels a proportion of one part of resinoid to seven parts by weight of abrasive is referred to.  For cold moulding a solvent such as glycol ether, with or without a non-solvent such as kerosene or creosote oil is preferred.  The use of chlorinated naphthalenes and of solutions of the glycerol resinoid is also referred to, and a lubricant such as calcium stearate may be used.  Heat may be applied to the mould, but preferably the moulded articles are baked in an oven.  Other resinoids such as phenolic resins may be components of the composition, and the alkyd resinoids may be other than glycerol alkyd resinoids.