Patent GB-410506-A (GB)
Title: Improvements in moulded articles of resinous materials
IPC: C08L29/14
Filed: 1932-08-13
Abstract: Moulded articles are manufactured by the injection moulding of compositions consisting of or containing a polyvinyl resin produced in accordance with the parent Specification by partial hydrolysis of a polyvinyl ester and simultaneous or subsequent reaction with an aldehyde.  The compositions may also contain one or more of the following: (a) Impart strength promoters: substances the molecule of which contains at least one aliphatic chain of more than eight carbon atoms, having a low but appreciable solubility or compatibility in the polyvinyl resins and causing a substantial increase in the toughness of the compound, e.g. calcium laurate, stearates or montan wax.  (b) Mould lubricants, capable of causing the compound to be repellent from the metal surfaces of the mould and of forming a lubricating layer on the walls of the heating cylinder and nozzle of the moulding machine, e.g. waxes, certain metal soaps or fatty acids. (c) Diluents: other resinous, plastic or plasticizing substances, e.g. natural gums and resins, permanently fusible synthetic resins including polyvinyl acetates, bitumen, dyestuffs and high boiling compatible substances known as plasticizers.  (d) Fillers or pigments of mineral, vegetable or animal origin of character and in amount such that they do not unduly interfere with the plastic flow of the mixture in the moulding machine or moulds and do not unduly affect the surface gloss of the product.  Suitable fillers are: cotton flock, bone black, the material known under the Registered Trade Mark.  "Asbestine," iron oxide, titanium oxide, lead carbonate, clay, melosil, or zinc oxide.  The last substance may be used in quantities practically up to maximum capacity, e.g. over 400 per cent of the amount of polyvinyl resin.  The characteristics of two or more of the foregoing may be combined in a single material.  Examples describe compositions for injection moulding in which a polyvinyl resin, made by 70 per cent hydrolysis of polyvinyl acetate in the presence of acetaldehyde, is mixed with: (1) montan wax and gum dammar; (2) calcium stearate and coumarone resin; (3) carnauba wax, polyvinyl acetate and acaroid gum; (4) calcium stearate and cotton flock; (5) montan wax, wax tailings, black dyestuff, bone black and zinc oxide; (6) carnauba wax, polyvinyl acetate, "Asbestine" and zinc oxide; (7) calcium stearate and zinc oxide; (8) montan wax, coumarone resin and zinc oxide.  The first Provisional Specification contains additional examples in which a polyvinyl resin is mixed with montan wax alone or with the addition of coumar resin, acaroid or acaroid and polyvinyl acetate.  Specification 383,216 is referred to in the Provisional Specification.ALSO:Compositions for injection moulding contain a polyvinyl resin produced in accordance with the parent Specification by partial hydrolysis of a polyvinyl ester and simultaneous or subsequent reaction with an aldehyde, with or without one or more of the following: (a) Impact strength promoters; substances the molecule of which contains at least one aliphatic chain of more than eight carbon atoms, having a low but appreciable solubility or compatibility in the polyvinyl resins and causing a substantial increase in the toughness of the material, e.g. calcium laurate, stearates or montan wax.  (b) Mould lubricants, capable of causing the compound to be repellent from the metal surfaces of the mould and of forming a lubricating layer on the walls of the heating cylinder and nozzle of the moulding machine, e.g. waxes, certain metal soaps or fatty acids.  (c) Diluents: other resinous, plastic or plasticizing substances, e.g. natural gums and resins, permanently fusible synthetic resins including polyvinyl acetates, bitumen, dyestuffs and high boiling compatible substances known as plasticizers.  (d) Fillers or pigments of mineral, vegetable or animal origin of character and in amount such that they do not unduly interfere with the plastic flow of the mixture in the moulding machine or moulds and do not unduly affect the surface gloss of the product.  Suitable fillers are: cotton flock, bone black, the substance known under the Registered Trade Mark "Asbestine," iron oxide, titanium oxide, lead carbonate, clay, melosil or zinc oxide. The last substance may be used in quantities practically up to maximum capacity, e.g. over 400 per cent of the amount of polyvinyl resin.  The characteristics of two or more of the foregoing may be combined in a single material. Examples describe compositions in which a polyvinyl resin is mixed with: (1) montan wax and gum dammar; (2) calcium stearate and coumarone resin; (3) carnauba wax, polyvinyl acetate and acaroid gum; (4) calcium stearate and cotton flock; (5) montan wax, wax tailings, black dyestuff, bone black and zinc oxide; (6) carnauba wax, polyvinyl acetate, "Asbestine" and zinc oxide; (7) calcium stearate and zinc oxide; (8) montan wax, coumarone resin and zinc oxide.  The first Provisional Specification contains additional examples in which a polyvinyl resin is mixed with montan wax alone or with the addition of coumar resin, acaroid or acaroid and polyvinyl acetate.  Specification 383,216 is referred to in this Provisional Specification.