Patent GB-591496-A (GB)
Title: Manufacture of resinous condensation products
IPC: C08G12/34
Filed: 1944-07-03
Abstract: Condensation products are prepared by reacting an aminotriazine and formaldehyde, or a partial condensate thereof, with a mono-amino-diphenyl, the molecular proportion of mono-amino-diphenyl to aminotriazine being at least 1 : 1.  In preferred processes a methylol compound of melamine and formaldehyde, preferably prepared at a pH of 6.5 to 10.0, particularly 7.5 to 9.5, is reacted with a mono-o-amino-diphenyl in the presence or absence of a water-insoluble solvent for the resin, e.g. xylene or toluene and preferably after a partial dehydration at pH 9.0 to 10.0.  Alternatively, the above methylol compound may be reacted with excess of mono-amino-diphenyl and then with further formaldehyde.  The proportions of reactants which may be used are: formaldehyde to aminotriazine; 1 : 1 or preferably 2 : 1 up to 6 : 1 or preferably 4 : 1, particularly 2.3 : 1; mono-aminodiphenyl to aminotriazine: 1 : 1 up to 4 : 1, e.g. 1.5 : 1, but the proportion of mono-aminodiphenyl should not exceed that of aldehyde.  The following materials are specified: aminotriazines: melamine; substituted melamines, e.g. chlorinated, alkylated or phenylated melamines; deaminated melamines, e.g. ammeline and ammelide; triethyl-, triphenyl-, trihydrazino-triazines; melam and melem; chloro- and methyl-amino-triazines; phenylamino-hydroxy-triazine and mixtures thereof: mono-aminodiphenyls: mono-o- and mono-p-amino-diphenyls and mixtures thereof; mono-amino-diphenyls substituted by groups non-reactive to aldehydes such as halogen or alky groups, e.g. mono-, di-, tri- and tetra-chloro-o-amino-diphenyls; and mono-, di- and tri-, methyl-, ethyl-, propyl- and butyl-amino-diphenyls. Before, during or after reaction fillers, plasticisers, solvents, diluents, thermosetting and thermoplastic synthetic resins or their ingredients, or natural resins may be introduced.  In examples, melamine and formaldehyde are reacted at a pH of 7.8, partially dehydrated at pH 9.4 and then reacted with mono-o-amino-diphenyl in the presence or absence of xylene and dehydration is completed; melamine and formaldehyde are reacted at pH 9.3, mono-o-diphenyl is added, and the mixture dehydrated.  The products are soluble in dilute acids, e.g. hydrochloric and sulphuric (forming salts), benzene, toluene, xylene, furfuryl alcohol and furfural (with which they react).  Products may be used for surface coatings, with or without previous reaction with furfural in production of grinding-wheels, by formation of metal salts in sizing agents for paper, treating agents for leather, anti-creasing agents for textiles, adhesives, e.g. for paper, wood, or cloth, and casting resins.  Thermosetting moulding compositions may be obtained by mixing the above products with fillers (such as wood flour, walnut shell flour, asbestos, mica, mineral wool, glass fibres, cloth cuttings, dyes, pigments, plasticisers and mould lubricants) and compounds containing a reactive methylene group such as formaldehyde, paraformaldehyde, hexamethylenetetramine, or partial condensation products of formaldehyde or other aldehydes (e.g. aliphatic aldehydes such as acetaldehyde, propionaldehyde, butyraldehyde, heptaldehyde, hexaldehyde; furfural; unsaturated aldehydes such as acrolein or methacrolein; aromatic aldehydes such as benzaldehyde; and mixtures of aldehydes) such as methylol aminotriazines (e.g. tetramethylol melamine), methylol ureas, methylol amides such as dicyandiamide-formaldehyde condensate and phenol-formaldehyde condensates.  In further examples, compositions consist of melamine-formaldehyde-mono-o-aminodiphenyl condensate prepared as above, extracted pine wood pitch known under the Registered Trade Mark "Vinsol" (or other acidic material, e.g. oxalic, phthalic or sulphamic acids or shellac), zinc stearate and silica flour, and a partial melamine-formaldehyde condensate and cotton flock or with paraformaldehyde; melamine-formaldehyde-mono-o - amino - diphenyl condensate, a partial melamine-formaldehyde condensate, zinc stearate, cotton flock and silica flour.  The compositions may be moulded by heat and pressure to form, e.g. discs and electrical insulation.  The Specification as open to inspection under Sect. 91 does not limit the relative proportion of mono-amino-diphenyl and aminotriazine, and admits the use instead of formaldehyde of compounds yielding it and the other aldehydes specified above.