GB815179A - Polyesters and condensation products thereof with aminoplasts - Google Patents

Abstract

A polyester having a molecular weight of about 800-1500, an acid number of about 90-100 and containing free hydroxyl groups is the condensation product of phthalic acid or an alkylated phthalic acid (or an anhydride thereof) with either (a) a polyester having an acid number of not over 10 and obtained from the condensation of 1 mol. of an aliphatic dibasic acid having 4-18 carbon atoms (or a dialkyl ester thereof) with 1.2-1.8 mols. of a polyol material of which at least 25 mol. per cent consists of a polyol containing at least 3 hydroxyl groups, or (b) a polyester of acid number not over 10 obtained as in (a) but modified by a fatty acid having 8-30 carbon atoms, the proportion of the phthalic acid or anhydride to the total polyol material being in the range of 1.67-3.5 mols. of the former for each 3 mols. of the latter. The polyol may be glycerine, sorbitol, pentaerythritol, di- or poly-pentaerythritol, inositol, tetramethylolcyclohexanol or trimethyol ethane and may contain up to 75 mol. per cent of a diol, e.g. ethylene-, diethylene-, 1.2-propylene, 1.3-propylene-, 1.3-butylene-, 1.4-butylene-, 1.5-pentylene-, diethylene- or dipropylene-glycol. Specified aliphatic dibasic acids are adipic, succinic, glutaric and sebacic acids. In making the modified polyester (b), the fatty acid or an ester thereof (e.g. with glycerol) may be reacted with the polyester (a) but is preferably first reacted with the polyol (or part of it) and the product then reacted with the aliphatic dibasic acid and any remaining polyol. The polyester may be reacted with a drying oil, a natural resin or shellac but is especially useful for reacting with an alkylated aminoplast. This may be obtained by reacting formaldehyde with urea, thiourea, imidazolidinone-2, acetoguanamine, benzoguanamine, melamine, an N,N- or N,N1-dialkyl melamine or an N-monoalkyl melamine and with a monohydric alcohol containing 3-6 carbon atoms. Prior to reaction with the polyester, the aminoplast may be reacted with an alkyd of molecular weight about 2000-10,000. This alkyd may be obtained by condensing a dicarboxylic acid, e.g. ortho-, iso- or tere-phthalic, succinic, glutaric, adipic or sebacic acids with a polyhydric alcohol e.g. ethylene glycol, diethylene glycol, glycerol, pentaerythriol, sorbitol, inositol, trimethylol ethane, tetramethylolcyclohexanol or di- or poly-pentaerythritol. Preferably the polyhydric alcohol component of the alkyd contains at least 25 per cent by weight of an alcohol containing at least three hydroxyl groups. Up to 50 per cent of the dicarboxylic acid may be replaced by an unsaturated dicarboxylic acid, e.g. maleic or fumaric acid or the reaction product of maleic anhydride and abietic, ricinoleic or eleostearic acid. The alkyds may be modified by a fatty acid containing 12-30 carbon atoms. The polyester after modification with the aminoplast (or alkyd modified aminoplast) is preferably neutralized with ammonia, an amine or a quaternary ammonium compound. Pigments, e.g. clays, kaolin, china clay, satin white, titanium dioxide, lithophone, barium sulphate, p-toner red, chrome green or ultramarine blue may be added. The neutralized products may be used as coating compositions (see Group VIII), impregnants for textiles (see Group IV (c)) or adhesives and for these uses are preferably diluted with water to a concentration of 5-40 per cent solids. They may be added to the aqueous compositions, thickeners, e.g. gum tragacanth, cellulose ethers, sodium alginate, polyvinyl alcohol or saponified polyvinyl acetate; wetting agents or penetrants e.g. triethanolamine stearate, alkylphenoxypolyethoxyethanols or octadecylbenzyldimethylammonium chloride. There may also be added aqueous dispersions of linear emulsion polymers e.g. derived by polymerizing acrylic, alpha-alkyl acrylic or alpha-halo acrylic esters of monohydric alcohols; the phenyl, benzyl or phenylethyl esters of the acrylic acids; substituted or unsubstituted vinyl aromatic compounds; vinyl and vinylidene halides; alkyl vinyl ketones; itaconic diesters; vinyl, allyl or methallyl esters of monocarboxylic acids; vinyl thiophene; nitriles containing a single CH2 = C< group and minor amounts of vinyl pyrrole, vinyl pyridine or N-dialkyl acrylamides. These polymers may also contain small amounts of other hydrophillic comonomers e.g. acrylic acid, methacrylic acid or itaconic acid. After applying the aqueous composition to a substrate, it is cured by heating it to 110-350 DEG C. In examples (1)-(10) phthalic anhydride is heated with a polyester derived from (1) adipic acid and trimethylol ethane; (2) adipic acid and glycerine; (3) succinic acid and sorbitol; (4) glutaric acid and pentaerythritol; (5) adipic acid, diethylene glycol and trimethylol ethane; (6) adipic acid, trimethylol ethane and lauric acid; (7) sebacic acid, trimethylol ethane and lauric acid; (8) adipic acid, diethylene glycol, trimethylol ethane and lauric acid; (9) glutaric acid, glycerol, trimethylol ethane and lauric acid; (10) adipic acid, trimethylol ethane and stearic acid; (11)-(12) adipic acid, trimethylol ethane and soyabean oil or coconut oil; condensation being effected in presence of sodium methylate and triphenyl phosphite. In further examples (13), (17) and (18) a butylated polymethylolmelamine, a butylated dimethylol urea or N.N1-diisopropoxymethylimidazolidinone is condensed with a polyester of Examples (1)-(12) and the product neutralized with ammonia or triethylamine and diluted with water to form a coating composition; (14), (15), (16) and (19) a butylated polymethylolmelamine, or a butylated polymethylol-N.N-dimethylmelamine is condensed with the polyester of Example (1) and the product after neutralization with triethylamine is mixed with a paste of titanium dioxide containing a nonionic dispersing agent, then diluted with water and thickened with sodium alginate to form a dispersion for printing textile fabrics; (20), (24) and (25) a butylated polymethylol melamine, a butylated dimethylol urea or N.N1-diisopropoxymethyl-imidazolidinone-2 is heated with a coconut oil modified glycerine-phthalate resin and the product heated with the polyester of Example (1), neutralized with ammonia or triethylamine and diluted with water to form a coating composition; (21), (22), (23) and (26) a butylated polymethylol melamine or a butylated polymethylol-N.N-dimethylmelamine is heated with a coconut oil or linseed oil modified glycerine-phthalate resin and the product heated with a polyester of Examples (2)-(12) and then neutralized with triethylamine; the co-reaction product is then mixed with titanium dioxide and the mixture diluted with water to form a dispersion for coating metal panels.ALSO:Wool is impregnated with an aqueous dispersion of a salt of a polyester resin and a solvent soluble aminoplast. The polyester resin is a condensation product of 1.67 to 3.5 mols. of o-phthalic acid, which may be C1 to C4 alkyl substituted in the ring, or an anhydride thereof, with 3 mols. of a polyester obtained by condensing at least one dibasic aliphatic acid having 4 to 18 carbon atoms, or a lower alkyl diester thereof, and 1.2 to 1.8 mols. of a polyol containing at least 25 mol. per cent of at least one polyol containing at least three hydroxyl groups, which (latter) polyester may be modified with a fatty acid having 8 to 30 C atoms (see Group IV (a)). The aminoplast is preferably the reaction product of formaldehyde with urea, thiourea, imidazolidinone-2, acetoguanamine, benzoguanamine, melamine, an N,N- or N,N1-dialkyl melamine or a N-monoalkyl melamine and with a monohydric alcohol containing 3-6 carbon atoms. The aqueous dispersion may also contain thickeners, e.g. gum tragacanth, cellulose ethers, sodium alginate, polyvinyl alcohol or saponified polyvinyl acetate; wetting-agents or penetrants, e.g. triethanolamine stearate, alkylphenoxypolyethoxy-ethanols or octadecylbenzyldimethylammonium chloride. There may also be added aqueous dispersions of linear emulsion polymers, e.g. derived by polymerizing acrylic, alpha-alkyl acrylic or alpha-halo-acrylic esters of monohydric alcohols; the phenyl, benzyl or phenylethyl esters of the acrylic acids; substituted or unsubstituted vinyl aromatic compounds; vinyl and vinylidene halides; alkyl vinyl ketones; itaconic diesters; vinyl, allyl or methallyl esters of monocarboxylic acids; vinyl thiophene; nitriles containing a single CH2=C < group and minor amounts of vinyl pyrrole, vinyl pyridine or N-dialkyl acrylamides. The polymers may also contain small amounts of other hydrophilic comonomers, e.g. acrylic acid, methacrylic acid or itaconic acid and may also be used for stiffening and pigment printing textiles. After applying the dispersion the condensate is cured by heating to 240-300 DEG F.