Patent GB-858612-A (GB)
Title: Novel polyisocyanates containing aromatic ester groups and a process for their production
IPC: C07C263/10
Filed: 1958-12-08
Abstract: Aromatic polyisocyanates containing carboxylic polyester groups are obtained by phosgenating the amino compounds obtained by esterifying aminobenzoic acid with polyvinyl alcohol or hydrolysed polyvinyl acetate or by reducing the polyesters obtained by reacting diethylene glycol and nitroisophthalic acid, the mixed esters of pentaerythritol, fatty acids, e.g. lauric acid, and m-nitrobenzoic acid, the mixed ester of adipic acid, ethylene glycol and nitrobenzoic acid or the mixed ester of adipic acid, ethylene glycol, trimethylol propane and nitroisophthalic acid.  Rubber adhesive solutions contain natural or synthetic rubber and aromatic polyisocyanates containing carboxylic ester groups (see Group IV(b)). Adhesives are described containing natural rubber, benzine, zinc oxide, colophony, methyl 3, 5-diisocyanatobenzoate and methylene chloride and chloroprene, zinc di-methyl dithicarbamate, trichloroethylene, ethyl acetate, methyl 3, 5-diisocyanatobenzoate and methylene chloride, Other synthetic rubbers specified for use in the adhesive solutions are butadiene-acrylonitrile and butadiene-styrene rubbers.ALSO:The invention comprises aromatic polyisocyanates containing carboxylic acid ester groups derived from aromatic polyamines containing carboxylic acid ester groups or the hydrochlorides thereof, by phosgenation, and methyl and benzyl 3, 5-diiso-cyanatobenzoates.  Ester-polyamine starting materials mentioned include 3, 5-diamino benzoic acid esters, e.g. the methyl and benzyl esters and esters thereof with polyhydric alcohols, e.g. triethylene glycol and trimethylol propane esters of m-amino-benzoic acid with polyhydric alcohols including polyvinyl alcohol or hydrolysed polyvinyl acetate.  Suitable starting materials may also be obtained by esterifying nitrocarboxylic acids, e.g. nitroisophthalic acid, with polyhydric alcohols and reducing the products to polyamino polyesters, e.g. diethylene glycol may be esterified with nitro-isophthalic acid and the product reduced or mixed esters of pentaerythritol, fatty acids, e.g. lauric acid, and m-nitrobenzoic acid or the mixed ester of adipic acid ethylene glycol and nitrobenzoic acid or the mixed ester of adipic acid, ethylene glycol, trimethylol propane and nitroisophthalic acid may be reduced. The phosgenation is carried out in the conventional manner, e.g. by cold phase-hot phase phosgenation or phosgenation of the correspondng amine hydrochlorides.  The process may be carried out in the presence of an inert solvent such as chlorobenzene or dichlorobenzene or nitrobenzene and intermittently or continuously.  Specific compounds prepared by the process are methyl and benzyl diiso-cyanatobenzenes, the product obtained by phosgenating the amino ester obtained by esterifying diethylene glycol with dinitrobenzoic acid and subjecting the product to catalytic hydrogenation, the product obtained by phosgenating the amino ester obtained by reacting diethylene glycol with m-nitrobenzoyl chloride and reducing the resulting nitro ester and the product obtained by esterifying 5-nitrobenzene -1, 3-dicarboxylic acid with ethylene glycol, further acetylating the terminal hydroxy groups with acetic anhydride and reducing the nitro ester obtained.  The products are employed in rubber adhesive compositions (see Group IV (a)), for modifying polyhydroxy compounds, cross-linking thermoplastics and in lacquer coatings.