GB415555A - Manufacture of condensation products capable of being moulded, and of moulded articles therefrom - Google Patents

Abstract

Condensation products of primary aromatic amines with formaldehyde are manufactured by reacting the amine or a salt thereof with more than an equimolecular proportion of formaldehyde in the presence of a considerable proportion, advantageously an equimolecular proportion, of a strong acid, e.g. a halogen hydracid or sulphuric acid, under such conditions that at least about half of the amine or salt thereof undergoes condensation in the presence of more than two molecular proportions of formaldehyde at an initial temperature of at least 50 DEG C., if desired in the presence of a filling agent, a dyestuff or a flux, the resin being precipitated by elimination of the acid, and, if required, washed and dried. The process may be carried out by adding more than two molecular proportions of formaldehyde as rapidly as possible to an acid solution of one molecular proportion of the amine having an initial temperature of at least 50 DEG C., or by adding the amine slowly to a quantity of formaldehyde amounting to at least 1,4 molecular proportions for each molecular proportion of the total amine to be introduced and having an initial temperature of at least 50 DEG C. The precipitated resin may be mixed with a filling agent, a softening agent, a dyestuff or a hardening agent, whilst the resin may be mixed at any stage of its production with a fibrous material and the mixture may be converted into sheets, e.g. paper or cardboard. Moulded articles are manufactured by the action of heat and pressure on the resins or the mixtures thereof with the substances specified above, or on a sheet or a number of super-imposed sheets made from the mixtures thereof with fibrous materials. In examples: (1) an aqueous solution of 2 molecular proportions of aniline hydrochloride is run slowly into a dilute hydrochloric acid solution of 10 molecular proportions of formaldehyde at 50 DEG C. and the product is precipitated by addition of caustic soda solution; (2) a solution of 3 molecular proportions of aniline in dilute hydrochloric acid is run slowly into a boiling dilute hydrochloric acid solution of 9 molecular proportions of formaldehyde, the product being precipitated as in (1); (3) 10 molecular proportions of commercial formaldehyde solution are added rapidly to an aqueous solution of 2 molecular proportions of aniline hydrochloride at 95 DEG C.; (4) as in (2) but using only 4,5 molecular proportions of formaldehyde; (5) a solution of 2 molecular proportions of m-toluidine in dilute hydrochloric acid is run into a boiling dilute hydrochloric acid solution of 6 molecular proportions of formaldehyde and the product is neutralized with caustic soda or sodium carbonate solution; the product is mixed with wood meal and moulded; (6) 3 molecular proportions of aniline are run slowly into a boiling solution of 9 molecular proportions of formaldehyde containing 1,5 molecular proportions of hydrochloric acid. Any of the foregoing condensation solutions or precipitated resins may be worked up with fibrous materials, e.g. cellulose or asbestos, into paper containing resin. The fibrous material in the beaten condition may be added to the reaction components or to the condensation solution, or the condensation solution may be run into the beaten pulp and the resin then precipitated on the fibre, or the precipitated resin, before or after washing, may be added to the cellulose or to the pulp, if desired, after drying and grinding. Softening agents, dyestuffs or hardening agents may be added to the resins or to the pulp. Specifications 284,589, [Class 2 (iii)], 342,326, 342,767, 368,300, 372,075, and 372,076 are referred to.