GB842154A - Polyisocyanate compositions - Google Patents

Abstract

The invention comprises the reaction products of a liquid poly isocyanate composition, obtained by phosgenating the polyamine composition obtained by condensing formaldehyde with a mixture of at least two aromatic amines, and less than the stoichiometric equivalent of at least one compound containing a plurality of isocyanate-reactive groups. The amines mentioned include aniline, toluidines, chloroanilines, anisidines, nitroanilines, m-phenylene diamine, m-toluylene diamine and chloro-m-phenylene diamine, preferably 4 to 5 moles of mixed amines per mole of formaldehyde are used to give predominantly a dinuclear product which is phosgenated in the usual manner. Isocyanate-reactive compounds mentioned include trimethylolpropane, hexane-triol, castor oil, ethanolamines, alkylene glycols, polyesters and polyesteramides containing hydroxyl and carboxyl groups as reactive groups and polyethers containing reactive hydroxyl groups; preferably 0,2 to 0,3 isocyanate-reactive groups are used per isocyanate group. This reaction may be carried out in a solvent, for example, a ketone or ester. The liquid polyisocyanates may first be modified by treatment with phenol or an acetoacetic ester to give products containing one or more "masked" isocyanate groups or polymerised e.g. to dimers containing uretedione linkages by treatment with pyridine or to isocyanurate polymers by treatment with a basic organic or inorganic metal compound. In the examples polyisocyanates derived from a) aniline and toluidine and (b) aniline and chloroaniline, are reacted with (a) trimethylolpropane, (b) hexane-triol, (c) triethanolamine, (d) diethylene glycol, (e) castor oil, (f) a polyester derived from adipic acid and glycerol and (g) a polyester derived from adipic acid, glycerol and ethylene glycol. Specification 809,809 is referred to.ALSO:The invention comprises liquid polyisocyanate compositions obtained by phosgenating the polyamine compositions obtained by condensing formaldehyde with a mixture of at least two aromatic amines. The condensation and phosgenation are carried out in the usual manner using 4 to 5 moles of amines per mole of formaldhyde so as to minimise the undesirable production of amines having more than two nuclei and preferably the proportions of amines are chosen so that no more than 80% by molecular proportions of any single amine is converted to the polyamine composition. Amines specified are aniline, toluidine, chloroanilines, anisidines, nitro-anilines, m-phenylene diamine, m-toluylene diamine and chloro-m-phenylene diamine. The polyisocyanates may be polymerised by treatment with, for example, pyridine to give dimers containing uretedione linkages or basic organic or inorganic metal compounds to give isocyanurate polymers. The polyisocyanates may be reacted with up to the theoretical quantity of phenol or an acetoacetic ester to give derivatives containing 1 or more "masked" isocyanate groups. The polyisocyanates may also be reacted with less than the stoichiometric equivalent e.g. 20 - 30% of the equivalent of at least one compound containing a plurality of isocyanate-reactive groups. This reaction may be carried out in a solvent such as ketone or ester using compounds such as trimethylol propane, castor oil, hexane triols, ethanolamines, alkylene glycols, polyesters and polyesteramides containing free hydroxyl or carboxyl groups or polyethers containing free hydroxyl groups. In examples the following amines are condensed with formaldehyde and the condensate phosgenated: (a) aniline and o-toluidine which give the new compound 4,41-di-isocyanate-3-methyl diphenylmethane, (b) aniline and o-chloroaniline, (c) aniline, o-toluidine and m-tolylene diamine. The di-isocyanate obtained in (a) is polymerised by treatment with sodium methoxide and lead 2-ethyl-hexoate. Specification 899,809 is referred to.ALSO:Cellular, rigid or flexible polyurethane products are prepared from high molecular weight polyhydroxy compounds and a polyisocyanate where the polyisocyanate used is a liquid polyisocyanate composition obtained by phosgenating the polyamine composition obtained by condensing formaldehyde with a mixture of at least two aromatic amines. Specification 809,809 is referred to.