Patent GB-700891-A (GB)
Title: Mixed esters, their preparation and compositions containing same
IPC: C08L67/00
Filed: 1951-10-19
Abstract: The invention comprises mixed esters which may be used in coating compositions containing cellulose derivatives or synthetic resins and which consist of a polyhydric alcohol wherein at least one of the hydroxyl groups is esterified with an aromatic monocarboxylic acid having one of its ring carbon atoms coupled to an open-chain aliphatic radical which contains a quaternary (i.e. a tertiary) carbon atom, and at least one of the remaining hydroxyl groups is esterified with a dissimilar carboxylic acid. Many open chain radicals are specified as groupings for the aromatic carboxylic acids and many of the latter acids, which may be substituted by halogens and alkoxy groups, are specified, representative being p - tert - butyl - benzoic, p 1- (1, 1-dimethyl - 3 - chloropropyl) benzoic, m - tert - hexyl - p - chlorobenzoic and 4 - tert - butyl - 1 - naphthone acid.  1, 1 - dimethylpropen - 2 - yl, 1 ,1- dimethyl - 3 - cyano - propyl and 1, 1 - diethyl - 3 - nitrohexyl are included in a list of specified open-chain radicals.  Preferably the aromatic acid contains a tertiary alkyl radical of 4-16 carbon atoms and of particular importance are acids with a single aromatic ring containing a tertiary alkyl radicle of 4 - 12 carbon atoms, preferably in the p - position to a carboxy group, and substituted by halogen or lower alkyl radicles, preferably straight chain alkyl radicals of 1 to 4 carbon atoms.  Preferred dissimilar acids are unsaturated acids especially polyethylenic monocarboxylic acids.  Representative of many specified are pentadienoic acid and acids derived from linseed, soybean, tung and dehydrated castor oil.  Rosin acids may also be used, e.g. abietic or pimaric acid. The alcohols may be esterified with a third acid and representative of such acids are acetic, stearic, phthalic, chlorophthalic and aconitic acids.  Preferably not more than about 20 per cent. of the hydroxyl groups are esterified with the third type of acid.  Representative of many polyhydric alcohols specified are ethylene glycol, glycerol, pentaerythritol, polypentaerythritol, polyglycerol, glycerol, monoallyl ether, sorbitol, carbohydrates, methyl trimethylol propane, di-ethylene glycol, 2 - ethyl hexanetriol - 1, 2, 6, tetrahydroxycyclohexane, 3, 31 - thiodipropanol, polyallyl, polyvinyl and polymethallyl alcohols and polyols made by reacting bis-phenols with epichlorhydrin. Preferred are polyhydric alcohols containing at least 3, especially 3 - 12, hydroxy groups and particularly aliphatic alcohols containing 3 - 8 hydroxy groups and 3 - 12 carbon atoms.  Pentaerythritol and polypentaerythritols are especially important.  The alcohols may contain alkoxy, halogen and ester substituents.  From 10 to 80 per cent. of the hydroxy groups may be esterified with the substituent aromatic acid and 20 - 90 per cent. with the dissimilar acid. Particularly advantageous are products in which 25 - 75 per cent. of the hydroxy groups are esterified with the substituted aromatic acid and the residue with the dissimilar acid.  Representative of specified products are:-linseed oil fatty acid ester of glycerol di- (tert.-butyl - benzoate), rosin esters of pentaerythritol tri - (tert. - butyl - benzoate) and of a polyallyl alcohol in which at least 3 hydroxy groups are esterified with tert.octylbenzoic acid, a soybean oil fatty acid ester of glycerol mono-tert.-butylbenzoate mono-acetate a soybean fatty acid diester of dipentaerythritol di-(tert.-butyl-benzoate) dibutyrate and glycerol di - (1, 1 - dimethyl - 3 - chloropropyl) benzoate monohexadienoate.  Of particular interest are esters of polyhydric alcohols with the substituted aromatic acid, a polyethylenic acid and a disimilar polycarboxylic acid such as phthalic, succinic, chlorophthalic, adipic or maleic acid.  For the preparation of the esters (see Group IV (b)).  The esters, especially those from rosin acids and drying oil fatty acids, may be used directly or in combination with a thinner or solvent in coating compositions. Fused driers, e.g. metallic resinates, linoleates and naphthenates, are preferably added, although other driers, e.g. litharge, lead acetate and carbonate, and manganese borate, may also be used.  The esters may be admixed with drying oils, e.g. tung, linseed, dehydrated castor and soybean oil, and with or without solvents and driers to produce varnishes.  The esters may be used in combination with other film-forming materials such as cellulose derivatives, vinyl type polymers and aldehyde-type condensation resins, many of which are indicated, representative being reaction products of formaldehyde, methacrolein, benzaldehyde and furfural with compounds such as phenols, urea, thiourea, acetyl - urea, guanidine and melamine. Representative of monomers from which vinyl - type polymers which may be admixed with the esters may be prepared are:-styrene, dichlorostyrene, vinyl phenol, acrylic acid, methyl methacrylate, vinylidene halides, vinyl bromide, acrylonitrile, vinyl chloroacetate and benzoate, divinyl succinate and vinyl crotonate.  Specified cellulose derivatives are the nitrate, acetate, propionate, stearate, valerate, acetostearate and acetotartrate and ethyl, methyl, butyl, benzyl and glycol cellulose.  In examples (1) pentaerythritol is treated with p-tert.-butylbenzoic acid and wood resin to give a product which is compatible with a vinylchloride - acetate resin, a chlorinated rubber and ethyl and nitrocellulose; (4) the product obtained by treating soybean monoglyceride with p - tert.- butylbenzoic acid and phthalic acid in xylene gives a lacquer with nitrocellulose; (5) glycerol, p-tert.-butyl - benzoic acid and 2, 4 hexadienoic acid give a product which is compatible with cellulose derivatives, e.g. the nitrate, and (6) polyallyl alcohol containing at least 5 hydroxy groups is treated with p - tert.- butyl benzoic acid, linseed oil fatty acids and wood rosin and the product diluted with white spirit to give a coating composition.ALSO:The invention comprises mixed esters consisting of a polyhydric alcohol wherein at least one of the hydroxyl groups is esterified with an aromatic monocarboxylic acid having one of its ring carbon atoms coupled to an open-chain aliphatic radicle which contains a quaternary carbon atom and at least one of the remaining hydroxyl groups is esterified with a dissimilar carboxylic acid.  They are used in coating compositions (see Groups III and IV (a)).  Many open-chain radicles are specified as groupings for the aromatic carboxylic acids and many of the latter acids, which may be substituted by halogen and alkoxy groups, are specified representative being p-tert-butyl-benzoic, p-(1, 1-dimethyl-3-chloropropyl) benzoic, m-tert-hexyl-p-chlorobenzoic and 4-tert-butyl-1-naphthoic acid. 1, 1-Dimethylpropen-2-yl, 1, 1-dimethyl-3-cyanopropyl and 1, 1-diethyl-3-nitrohexyl are included in a list of open-chain radicles.  Preferably the aromatic acid contains a tertiary alkyl radicle of 4-16 carbon atoms and of particular importance are acids with a single aromatic ring containing a tertiary alkyl radicle of 4-12 carbon atoms, preferably in the p position to a carboxy group, and substituted by halogen or lower alkyl radicles, preferably straight-chain alkyl radicles of 1 to 4 carbon atoms. Preferred dissimilar acids are unsaturated acids especially polyethylenic monocarboxylic acids.  Representative of many specified are pentadienoic acid and acids derived from linseed, soyabean, tung and dehydrated castor oil.  Rosin acids may also be used, e.g. abietic and pimaric acid.  The alcohols may be esterified with a third acid and representative of acids specified are acetic, stearic, phthalic, chlorophthalic and aconitic acids. Preferably not more than about 20 per cent. of the hydroxyl groups are esterified with the third type of acid.  Representative of many polyhydric alcohols specified are ethylene glycol, glycerol, pentaerythritol, inositol, carbohydrates, methyl trimethylol propane, glycerol monoallyl ether, diethylene glycol, 2-ethyl hexanetriol-1, 2, 6-tetrahydroxycyclohexane, 3, 31-thiodipropanol, polyvinyl and polyallyl alcohol and condensation products of bisphenols with epichlorhydrin. Preferred are polyhydric alcohols containing at least 3, especially 3-12 hydroxyl groups and particularly aliphatic alcohols containing 3-8 hydroxyl groups and 3-12 carbon atoms. Pentaerythritol and polypentaerythritols are especially important. The alcohols may contain alkoxy, halogen and ester substituents. 10-80 per cent. of the hydroxyl groups may be esterified with substituted aromatic acid and 20-90 per cent. with the dissimilar acid.  Particularly advantageous are products in which 25-75 per cent. of the hydroxy groups are esterified with the substituted aromatic acid and the residue with the dissimilar acid. Representative of listed products are: linseed oil fatty acid ester of glycerol di-(tert-butyl-benzoate), rosin acid esters of pentaerythritol tri-(tert-butyl-benzoate) and a polyallyl alcohol in which at least three hydroxyl groups are esterified with tert - octylbenzoic acid, a soyabean fatty acid ester of glycerol mono-tert-butylbenzoate monoacetate, a soyabean fatty acid diester of dipentaerythritol di-(tert-butyl-benzoate) dibutyrate and glycerol di-(1, 1-dimethyl-3-chloropropyl) benzoate monohexadienoate.  Of particular interest are esters of polyhydric alcohols with the substituted aromatic acid, a polyethylenic acid and a dissimilar polycarboxylic acid such as phthalic, succinic, chlorophthalic, adipic or maleic acids.  The esters may be made by esterifying the alcohol with a mixture of the acids, by an ester-interchange reaction between the alcohol or a lower aliphatic acid ester thereof and the lower aliphatic alcohol esters of the substituted aromatic acid and the dissimilar acid and by a combination of direct esterification and ester-interchange.  Catalysts may be used but their