Patent GB-666217-A (GB)
Title: Thermosetting wood filler composition
IPC: C09D5/34
Filed: 1948-05-27
Abstract: A wood filling composition containing a thermosetting resin, a pigment and an oil, comprises 70 to 90 parts (by weight) of a thermosetting resin, a volatile solvent for the resin, e.g. in amount of 25 to 40 per cent of the total weight of the filler, 10 to 30 parts of a mineral or fatty oil but not in excess of the oil-absorption value of the pigment for the oil, and for each 10 to 30 parts of the oil and resin 70 to 90 parts of a pigment having an oil-absorption value not in excess of 50 as determined by the spatula-rubbing method.  The resin may be a water- or organic solvent-soluble, acid-hardenable urea-, melamine- or phenol-formaldehyde resin, and may be modified in part by the addition of compatible natural and synthetic resins, e.g. rosin, ester-gums, damar, copals, fatty oil- and fatty acid-modified alkyds and drying-oil-soluble phenol-aldehyde resins.  Fatty oils specified are: tung, linseed, oiticica, soya bean, fish, cotton seed, corn, rape, wheat, castor, olive, rice, grapeseed and hazelnut oils, and may be raw, heat-bodied, blown or partially polymerized.  Drier metals which may be added to the composition are the naphthenates, linoleates and resinates of Pb, Co, Mn, Fe and Zn.  Volatile solvents specified are: water, ethylene-, diethylene-, triethylene-, propylene-and dipropylene glycols and their ether derivatives, e.g. ethylene glycol monoethyl- and monobutyl-ethers, diethylene glycol monomethyl-, monoethyl- and monobutyl-ethers, ethylene glycol diethyl ether, diethyleneglycol diethylether and diethyleneglycol methyl (n) butyl ether. Pigments specified are: iron oxides, umbers, siennas, carbon blacks, lead oxides and carbonates, zinc oxide, titanium oxide, ultra-marine blues, chrome green, chromium oxide, infusorial earths, gypsum, terra alba, barytes, blanc fix<\>ae, barium carbonate, clay, asbestine, whiting and marble dust.  The filler composition may be made by mixing the components in ball or pebble mills, pony mixers or roller mills, or the pigment may be initially dispersed in the oil and sufficient solvent to form a wet paste and then adding the resin.  The filler compositions may be applied to wood surfaces by brushing, spraying or dipping, and after removing excess of filler, sealer coating(s) and finishing coating(s) are applied with subsequent heat-conversion by air-drying, force-drying or baking, which may be promoted by acidic hardeners, e.g. mineral acids and acid reacting salts such as H2SO4, HCl, H3PO4 and NH4Cl. The hardeners may be incorporated in the filler composition, but they are preferably added to the sealer or finishing coating.  Examples are given.  A sealing composition comprises, according to example (II), an alcoholic (mixture of ethyl and amyl alcohols) solution of a phenol-aldehyde resin, 2 per cent of H2SO4, and 15 per cent of silica gel, and according to example V, a mixture of butanol, xylol, toluol, a fatty acid polyester resin, and ester gum modified phenol-formaldehyde resin and a butanol-modified urea-formaldehyde resin.  A suitable top-coating is similar to the sealing composition of example (II) but with omission of the silica gel; other top coatings specified are the alcohol-soluble melamine- and urea-formaldehyde resins prepared, e.g. by reacting melamine or urea and formaldehyde in the presence of butyl or octyl alcohol, both of which may be plasticized with fatty oil- and fatty acid-modified alkyd resins, and phenol-formaldehyde resins prepared by reacting phenol with excess molar quantities of formaldehyde in the presence of an alkaline catalyst.  The filling compositions may be applied to plywood structures after or during their manufacture.  Specification 552,644, [Group IV (b)], and U.S.A. Specification 2,190,672 are referred to.  The compositions in the Specification as open to inspection under Sect. 91 are not restricted to the proportions of those in the accepted Specification.ALSO:Wood surfaces are filled by applying a filling composition, comprising a thermosetting resin, a volatile solvent for the resin, a mineral or fatty oil and a pigment (see Group IV(a)), to the wood surface, e.g. by brushing, spraying or dipping, and wiping off excess filler.  The filled surface may then be coated with a sealer coating or coatings comprising a thermosetting resin in solution in an organic solvent, and with a further coating or coatings comprising a heat-convertible resin in an organic solvent with subsequent heat conversion by air-drying, force-drying or baking.  Alternatively, heat-conversion may be effected after the application of each coating.