GB650247A - Improvements in and relating to alkyd-polysiloxane resins - Google Patents

Abstract

An alkyd-polysiloxane resin is made by mixing an oil-modified alkyd resin containing free OH groups with an organo-polysiloxane containing silicon-bonded alkoxy radicals and heating the mixture with simultaneous removal of the alkanol formed during the reaction. The organo-polysiloxanes used, which may contain from 0.1 to 2.5 methyl and phenyl radicals per silicon atom, are those described in Specifications 542,655, 544,143, 548,911, 548,912 and 551,649 and those of lower molecular weight such as dibutoxy-tetramethyldisiloxane, dipropoxytetramethylcyclo-trisiloxane and dibutoxytetraphenyldisiloxane, and may be made by heating organoalkoxysilanes, e.g. methyltripropoxy-, methyltributoxy-, dimethyldibutoxy-, tri - isopropylpropoxy-, diethyldihexoxy-, phenyltributoxy-, diphenyldibutoxy- and methylphenyldipentoxysilanes, with an acid catalyst (e.g. in amount of 0.1 to 6.0 per cent by weight) such as glacial acetic acid and sufficient water to remove the alkoxy radicals, or by hydrolysing and alcoholizing an organohalogenosilane with sufficient alcohol and water to remove the halogen but insufficient to complete the hydrolysis. The alkyd resin may be made from one or more polybasic acids, e.g. oxalic, malonic, succinic, glutaric, adipic, tricarballylic, phthalic, isophthalic, terephthalic and 4-chloro-phthalic acids or their anhydrides, and a molar excess of a polyhydric alcohol, e.g. ethylene-, diethylene-, propylene- and trimethylene glycols, glycerine, trimethylolpropane, pentaerythritol, polyallyl alcohol, sorbitol and mannitol, and modified by oils (5 to 80 per cent by weight), in the raw, heated or blown state, e.g. linseed, rapeseed, cottonseed, chinawood, castor (excluding the raw oil), dehydrated castor, soyabean, perilla, oiticica, linseed oil acids, coconut oil fatty acids, ricinoleic acid, glycerides of linoleic and linolenic acids, palmitic, oleic and stearic acids, babassu oil, palm oil, fish oils and fish oil acids such as clupanodonic, and fatty oil acids derived therefrom. In examples, a butoxy phenyl polysiloxane in xylene is heated with an alkyd resin made from (1) glycerine, phthalic anhydride, coconut oil acids and xylene; (2) pentaerythritol, phthalic anhydride, coconut oil acids and xylol, enamels (3) being made therefrom by the addition of xylene and titania; (4) the alkyd resin of (1) was heated with a polysiloxane of the formula <FORM:0650247/IV (a)/1> , where X is an integer >1, prepared from methyltrichloro- and dimethyldichloro-silanes and butanol; the alkyd resin of example (2) is heated with (5) <FORM:0650247/IV (a)/2> and with (6) <FORM:0650247/IV (a)/3> ; (8) the alkyd resin of (2), but containing more pentaerythritol, is heated with <FORM:0650247/IV (a)/4> prepared from dimethyldichlorosilane, butanol and the catalyst FeCl3.6H2O. Other resins, e.g. rosin, shellac, kauri, dammar, coumaroneindene, phenolic or other alkyd resins and mixtures thereof may be added to the compositions. Other solvents, or mixtures thereof, specified are: methyl cyclo-hexanone, methyl isobutyl ketone, mesityl oxide, methyl-n-amyl ketone, di-isobutyl ketone, glycol diacetate, butyl lactate, tetralin, benzene, butanol, benzyl alcohol, nitromethane, 1-nitropropane, 2-nitropropane, the nitrobutanes, the nitropentanes, carbon tetrachloride, pentachlorethane, ethylene dichloride, and the ethyl and butyl ethers of ethylene glycol. Specification 583,754 also is referred to. The Specification as open to inspection under Sect. 91 comprises also using a liquid methyl polysiloxane containing silicon-bonded alkoxy groups as a modifying ingredient in place of oily modifying ingredients employed in alkyd resin manufacture, this, in example (9), phthalic anhydride, pentaerythritol, liquid methyl butoxysiloxane (as in example (8)) and xylene are heated together. This subject-matter does not appear in the Specification as accepted.ALSO:Organoalkoxysilanes, e.g. methyltripropoxysilane, methyltributoxysilane, dimethyldibutoxysilane, tri-isopropylpropoxysilane, diethyldihexoxysilane, phenyltributoxysilane, diphenyldibutoxysilane and methylphenyldipentoxysilane, are made by adding the particular organohalogenosilane to at least an equivalent amount of a primary alcohol.