Patent GB-433536-A (GB)
Title: Improvements in the manufacture and production of urea-formaldehyde condensation products
IPC: C08G12/42
Filed: 1934-02-12
Abstract: Condensation products are manufactured by subjecting the products obtainable by condensation preferably in the presence of acid condensing agents, of urea and/or thiourea and formaldehyde or its polymers, or of methylol derivatives of urea and/or thiourea or alkyl ethers thereof, or of amorphous products of high molecular weight obtainable from the said methylol compounds by splitting off water, or of mixtures of the said substances, in a monohydric alcoholic solvent, to condensation in the presence of an aliphatic alcohol containing more than 8 carbon atoms in the molecule, neutralizing the reaction mixture, expelling any excess of the alcoholic solvent and heating the remaining resinous product until it has become soluble in aromatic hydrocarbons.  The alcohols of high molecular weight are advantageously employed together with the monohydric alcoholic solvents, but it is also possible to cause the condensation product prepared in the presence of the monohydric alcoholic solvent to react, after neutralization and removal of the excess of solvent, with the alcohol of high molecular weight.  As monohydric alcoholic solvents may be employed aliphatic alcohols containing up to 6 carbon atoms in the molecule, ethylene glycol monoalkyl or aryl ethers or benzyl alcohol.  Suitable alcohols of high molecular weight are naturally occurring alcohols such as cetyl or myricyl alcohol, the alcohols contained in montan wax or those obtained by hydrogenation of natural saturated or unsaturated fatty or wax acids, e.g. the acids of animal or vegetable fats, oils or waxes such as beef tallow, spermaceti, sperm oil, palm kernel oil, linseed oil, poppy oil, castor oil, coconut oil, beeswax, Japan wax, carnauba wax or montan wax, also the alcohols obtainable by hydrogenation of the fatty acids obtained by the oxidation of paraffin wax, or the alcohols obtained directly in the said oxidation, or mixtures of these alcohols.  The amount of the alcohols employed may vary within wide limits, but should preferably be not less than 20 per cent by weight of the urea-formaldehyde condensation products, whilst the amount of the monohydric alcoholic solvent should be not less than 50 per cent by weight of the condensation products.  The step of expelling the solvent may be performed under a simultaneous mechanical treatment, and the subsequent heat treatment, which is limited to a minimum and in some cases must only be carried on for a rather short time, may be performed at about 80--130 DEG  C.  The products may be worked up alone or together with cellulose esters or ethers, e.g. nitrocellulose or benzyl cellulose, and the usual softening agents or with drying oils to form lacquers or adhesives.  The resins after adding a suitable acid or acid-forming hardening agent, such as phthalic anhydride, and if desired with the addition of softening agents such as dibutyl phthalate, tricresyl phosphate or glycerine trihydroxy ethyl ether, may be employed for preparing cast articles which harden on heating and are suitable as substitutes for glass. If the resins are kneaded on rollers while heating, preferably at 80--90 DEG  C., until they become hard and brittle in the cold, they may be pressed, after grinding, to form transparent articles.  Before casting or during the rolling there may be added softening agents, dyestuffs or fillers of organic or inorganic nature, whilst rubber may be incorporated on the rollers.  In examples: (1) dimethylolurea is heated with butanol, ethyl alcohol, urea nitrate and the mixture of alcohols obtained from the acids of palm kernel oil, the reaction mixture is neutralized with tertiary sodium phosphate, the excess of butanol is removed in a vacuum kneading machine and the resin is further kneaded at 85--95 DEG  C.; (2) dimethylolurea is heated with ethyl alcohol, urea nitrate and a fraction of the alcohols employed in (1) consisting mainly of alcohols containing 12--14 carbon atoms in the molecule, and the product is worked up as in (1); a lacquer may be prepared from the product together with nitrocellulose; (3) as in (1) but using a smaller amount of dimethylolurea; a lacquer may be prepared by dissolving the resin together with linseed oil in oil of turpentine; by adding a hardening agent, e.g. phthalic anhydride, during the kneading, a product is obtained which can be hardened in moulds; if the resin be rolled with the addition of phthalic anhydride until hard and brittle when cold, there is obtained after grinding, if desired with the addition of a stronger hardening agent, e.g. oxalic acid, a moulding powder which may be pressed into plates, if desired with the addition of a filler, e.g. cellulose; (4) a solution of a urea-formaldehyde condensation product in butyl alcohol is heated with the alcohols obtained from crude montan wax (e.g. by steam distillation after saponification), the free butyl alcohol is distilled off in a kneading machine in vacuo and the resin is further kneaded at 90 DEG  C.; the product yields cast articles as in (3); (5) paraformaldehyde is condensed with urea in butanol and ethyl alcohol, urea nitrate is added, the mixture is heated with oleyl alcohol, neutralized with tertiary sodium phosphate and worked up as in (1); (6) octodecyl alcohol is used instead of the montan wax alcohols in (4); films from solutions of the product become clear on hardening, particularly if phthalic anhydride be added to the solution; (7) octodecandiol is employed in the process of (4), phthalic anhydride is added during the kneading and the product is hardened in moulds; (8) a resin obtained by condensing dimethylolurea in butanol and removing excess of solvent is kneaded at 85 to 95 DEG C. in vacuo with the alcoholic fraction employed in (2) and the product is hardened in moulds with the addition of phthalic anhydride; (9) urea and aqueous formaldehyde are condensed in butanol, the product is mixed with toluene, dehydrated in a kneading machine in vacuo, and heated with urea nitrate and the alcoholic fraction employed in (2), the mixture being neutralized with tertiary sodium phosphate and worked up as in (1); the product may be worked up to cast or pressed articles or lacquers as in (3); (10) a mixture of dimethylolurea and dimethylolthiourea, or dimethylolthiourea alone, is heated with butanol, ethyl alcohol and octodecyl alcohol as in (1), and the product is kneaded with phthalic anhydride and hardened in moulds. Specifications 261,029, 332,634, [both in Class 2 (iii)], 356,731, 396,769, and 404,664 are referred to.