Patent GB-441052-A (GB)
Title: Improvements in compositions containing synthetic resins
IPC: C08K5/098
Filed: 1934-04-05
Abstract: Compositions, suitable for moulding in the press or by the injection method and for the formation of films by extrusion or by the use of solvents and diluents and brushing, spraying or flowing the solution on to a surface to be coated, comprise a partially or substantially completely acetalized polyvinyl ester resin mixed with a paraffinic or pseudo-paraffinic active impact strength promoter, i.e. a substance having a low but appreciable solubility in and compatibility with the resin, the presence of which, in proportions (usually 2--10 per cent) between the limits of solubility and compatibility causes a substantial increase in the toughness of the compound as measured by its impact resistance, such substance being employed alone or in conjunction with a latent impact strength promoter, i.e. an otherwise inactive body, the particles of which become coated with and act as carriers of the active impact strength promoter.  Substances suitable as impact strength promoters are: active: paraffin wax; pseudo-paraffinic substances, i.e. substances the molecules of which contain at least two normal carbon chains of at least eight members linked by a divalent polar group and thus capable of linear alignment to allow the formation of an extended molecule which differs from a paraffin hydrocarbon only in that it contains a discontinuity in its less reactive central part, e.g. ester waxes and the divalent metal salts and dihydric alcohol esters of monobasic aliphatic acids derived from normal paraffin hydrocarbons containing more than eight carbon atoms, e.g. stearic, palmitic, caprylic, lauric and oleic acids; latent: inorganic paint pigments, e.g. white lead and titanium oxide; zinc oxide or sulphide; barium fluoride and other insoluble fluorides of divalent metals. The use of ester waxes or metallic stearates otherwise than in conjunction with latent impact strength promoters is disclaimed.  The compositions may also contain one or more of the following modifying admixtures: (a) emollients, i.e. substances which reduce hardness and form stability, e.g. dibutyl phthalate, tricresyl phosphate, castor oil, stearic acid; (b) lubricants, i.e. substances which serve to lubricate the resins for moulding and impart repellancy to the resin with regard to the moulds, e.g. paraffin wax and salts of divalent metals with straight chain aliphatic acids containing more than eight carbon atoms, in proportions within or above the range within which they act as impact strength promoters, also fatty oils and aluminium stearate; (c) form stabilizers, i.e. substances which suppress plasticity and increase form stability, e.g. yacca gum and related substances; (d) diluents, e.g. natural and synthetic resins and gums, such as rosin, copals, dammar, coumarone resins and wax tailings; (e) fillers or pigments of mineral, vegetable or animal origin, of character and in amount such that they do not unduly interfere with the desirable properties of the compound, e.g. the substance known under the Registered Trade Mark "Asbestine," cotton flock, bone black, clay, wood meal, limestone, lead carbonate, iron oxide, carbon black, lead chromate, and also zinc oxide, titanium oxide and barium fluoride in amounts exceeding their range as latent impact strength promoters.  In examples, a polyvinyl resin produced by aldehyde condensation of 70 per cent hydrolysed polyvinyl acetate of 15 centipoises viscosity, is mixed with : (1) paraffin wax; (2) magnesium palmitate; (3) lead oleate; (4) zinc laurate; (5) ethylene glycol distearate; (6) zinc stearate and barium fluoride; (7) calcium stearate and zinc oxide. Specifications 337,806, [Class 2 (iii)], 405,986, 410,770; and 414,703, [Group V], are referred to.  The first Provisional Specification contains additional examples 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) montan wax, coumarone resin and zinc oxide.