Patent GB-405986-A (GB)
Title: Improvements in and relating to paints and varnishes
IPC: C09D129/14
Filed: 1932-08-11
Abstract: Lacquers, paints, varnishes, and enamels are manufactured by dissolving, in a suitable organic solvent or mixture of solvents, at least one "secondary resin" obtained from a partially hydrolysed polyvinyl organic ester, e.g. polyvinyl acetate, by simultaneous or subsequent reaction with an aldehyde, e.g. acetaldehyde.  There may also be added nitrocellulose or other cellulose ester or a cellulose ether, plasticizers or flexibilizers, e.g. high boiling esters such as butyl phthalate, amyl tartrate or aromatic esters, e.g. benzyl benzoate or tricresyl phosphate, drying oils, e.g. castor oil, raw linseed oil or wood oil, if desired with the addition of a drier, also the fatty acids from linseed oil, natural or artificial resins, especially shellac and colophony but also, for example, manila copal, sandarac, mastic, elemi, dammar, ester gum from rosin or copal, resins obtained by chlorination of diphenyl or of naphthalene, polymerization products of vinyl chloride, phenol-formaldehyde resins, phenolaldehyde-copal resins ["Albertols" (Registered Trade Mark) or "Amberols"], and resins obtained from coal tar naphtha by polymerization (coumarone resins), waxes, e.g. carnauba or montan wax, bituminous compounds, indiarubber, and pigments.  A small amount of an organic base may be added as a stabilizer.  Suitable solvents are: hydrocarbons: benzene, toluene, xylene if mixed with a small amount of alcohol, solvent naphtha from coal tar similarly to xylene; alcohols: methyl alcohol, ethyl alcohol (industrial alcohol being better than absolute alcohol, which should not be used alone), butyl or amyl alcohol with the addition of small amounts of lower alcohols or of aromatic hydrocarbons, diacetone alcohol, cyclohexanol, methyl cyclohexanol, benzyl alcohol, allyl alcohol; aldehydes: acetaldehyde, paraldehyde, benzaldehyde, furfural; ketones: acetone, methyl ethyl ketone, cyclohexanone, methyl cyclohexanone; esters and ethers: ethylene glycol monoethyl ether and derivatives, e.g. the acetate and the methyl derivative, anisole, dioxane, diphenyl oxide, ethyl, butyl, amyl and benzyl acetates, butyl and amyl phthalates, cyclohexanol acetate, ethyl lactate, benzyl benzoate, ethylidene diacetate; bases: aniline, pyridine; chlorinated hydrocarbons: chlorbenzene, chlornaphthalene (e.g. the commercial polychlor body), chloroform, dichlorethylene, trichlorethylene, tetrachlorethane, o-chlortoluene.  Advantageously a mixture of a low boiling (below 100 DEG  C.), a medium boiling (100--150 DEG  C.) and a high boiling (above 150 DEG  C.) solvent is used, though for special purposes two only or even one may be employed, e.g. for French polishes only a low boiling solvent is necessary, whilst for brush enamels the low boiling solvent may be reduced in amount or omitted.  In examples of the manufacture of secondary resins for use according to the invention: (A) vinyl acetate (containing some acetaldehyde) is heated in toluene solution in the presence of a catalyst prepared by reacting acetic anhydride and sodium perborate in toluene and separating the liquid portion of the product, which contains the active catalyst: the polymerized product is refluxed for 9 hours with butyl acetate, butyl alcohol, water, acetaldehyde and sulphuric acid, whereby 80 per cent of the acetyl groups are split off and the hydroxyl groups combine with the aldehyde; the hydrolysis and reaction with aldehyde may be carried out separately, in which case the sulphuric acid of the first step may be used as catalyst in the second or may be removed or neutralized and replaced by another catalyst; (B) vinyl acetate, with the addition of some acetaldehyde, is heated in benzene solution in the presence of a catalyst prepared as in (A) but using benzene instead of toluene; the product is treated as in (A) but using more solvent and a heating period of 8 hours, whereby 70 per cent hydrolysis occurs; (C) vinyl acetate (containing some acetaldehyde) is heated in commercial butyl acetate solution in the presence of a catalyst prepared as in (A) but using commercial butyl acetate as solvent; the product is treated for 8--9 hours as in (A), whereby 70 per cent hydrolysis occurs; (D) as in (C) except that the hydrolysis and reaction with acetaldehyde is only carried on for about 6 hours, whereby 50 per cent hydrolysis occurs. The properties of the products can be varied by varying the degree of polymerization and of secondary resin formation, which may be controlled by selection of catalyst, solvent and conditions of temperature, pressure and concentration.  The following examples of lacquers &c. are given: (1) a clear lacquer for metal or wood, applicable by brushing or spraying: resin (C), tricresyl phosphate and methylated spirits; (2) a French polish: resin (B), garnet lac and methylated spirits; (3) a brushing varnish for metal or wood, or for use as a high gloss finish over paint: resin (A), dibutyl phthalate, castor oil, dewaxed dammar, methylated spirit, diacetone alcohol, glycol ether and solvent naphtha; (4) a spirit varnish for brushing and spraying suitable for high gloss wood finish: resin (D), garnet lac, rosin and methylated spirit; (5) a wood sealing lacquer for spraying: resin (A), ester gum, dibutyl phthalate, toluene, xylene and methylated spirit; (6) a wood finishing lacquer: resin (B), ester gum, castor oil, amyl phthalate, methylated spirit and toluene; (7) a light green spraying enamel: resin (C), "Timonox" (Registered Trade Mark) (Sb2O3), chrome green, methylated spirit, benzene, toluene, xylene, cyclohexanone, and cyclohexanol acetate; (8) a medium green brushing enamel: resin (A), dewaxed dammar, castor oil, dibutyl phthalate, chrome green, methylated spirit, diacetone alcohol, ethylene glycol mono-ethyl ether and solvent naphtha; (9) a pale blue spraying enamel: resin (B), "Timonox," zinc oxide, barytes, Caledon Blue (light fast), methylated spirits and naphtha; (10) a white spraying enamel: resin (B), "Titanox," "Timonox," zinc oxide, barytes, methylated spirits and naphtha; (11) a yellow enamel: resin (B), "Titanox," "Timonox," zinc oxide, barytes, raw linseed oil (or wood oil), cobalt linoleate drier, Sudan Yellow G.R., solvent naphtha and methylated spirits; (12) resin (B), "Titanox," "Timonox," zinc oxide, barytes, carnauba wax, Sudan Brown R, solvent naphtha and methylated spirits; (13) resin (B), nitrocellulose known as "\ba1/2\be second cotton" (dry), dibutyl phthalate, Nigrosine, toluene, butyl alcohol, ethyl and butyl acetates; (14) resins (A) and (B) and methylated spirits; (15) resin (B), raw linseed oil, cobalt linoleate drier, aniline (as stabilizer), toluene and methylated spirits; (16) a brush enamel: resin (B), dewaxed dammar, blown castor oil, Deep Brunswick Green (a mixture of chrome yellow and Prussian blue), ethyl lactate, butyl acetate, butyl alcohol, toluene and xylene; (17) a primer suitable for application to steel, preferably by spraying, prior to the use of a pigmented secondary resin lacquer: resin (B) or (C), toluene, methylated spirits, and xylene; (18) a filler undercoat for use with a secondary resin enamel: resin (A), ester gum, blown castor oil, lithopone, slate powder, "Titanox," barytes, "Asbestine," (Registered Trade Mark) black oxide of iron, toluene, methylated spirits and methyl-cyclohexanol; (19) resin (B), hard wood pitch, toluene and methyl alcohol; (20) resin (A) and rubber dissolved separately in cyclohexanol, the solutions being mixed and the insoluble portion of the rubber filtered off; (21) as in (20) but part of the cyclohexanone being replaced by benzene and toluene. Specifications 351,082, [Group IV], and 378,608 are referred to. The Provisional Specification comprises the use of resins obtainable by the process of Specification 351,082 in general. Amyl stearate is referred to as an additional softening agent, and a manganese dryer is stated to be suitable for use in a lacquer containing linseed oil.  Specification 367,102 is also referred to in the Provisional Specification.ALSO:Synthetic resins, referred to as "secondary resins," are manufactured by partially hydrolysing a polyvinyl organic ester, e.g. polyvinyl acetate, and simultaneously or subsequently reacting it with an aldehyde, e.g. acetaldehyde.  The properties of the products can be varied by varying the degree of polymerization and of secondary resin formation, which may be controlled by selection of catalyst, solvent and conditions of temperature, pressure and concentration.  In examples: (1) vinyl acetate (containing some acetaldehyde) is heated in toluene solution in the presence of a catalyst prepared by reacting acetic anhydride and sodium perborate in toluene and separating the liquid portion of the product, which contains the active catalyst; the polymerized product is refluxed for 9 hours with butyl acetate, butyl alcohol, water, acetaldehyde and sulphuric acid, whereby 80 per cent of the acetyl groups are split off and the hydroxyl groups combine with the aldehyde; the hydrolysis and reaction with aldehyde may be carried out separately, in which case the sulphuric acid of the first step may be used as catalyst in the second or may be removed or neutralized and replaced by another catalyst; (2) vinyl acetate, with the addition of some acetaldehyde, is heated in benzene solution in the presence of a catalyst prepared as in (1) but using benzene instead of toluene; the product is treated as in (1) but using more solvent and a heating period of 8 hours, whereby 70 per cent hydrolysis occurs; (3) vinyl acetate (containing some acetaldehyde) is heated in commercial butyl acetate solution in the presence of a catalyst prepared as in (1) but using commercial butyl acetate as solvent; the product is treated for 8--9 hours as in (1), whereby 70 per cent hydrolysis occurs; (4) as in (3) except that the hydrolysis and reaction with acetaldehyde is only carried on for about 6 hours,