GB1484278A - Chemically resistant thermosetting polymers based on acrylate esters of phenolic resins - Google Patents

Abstract

1484278 Polymerizable ester resins UNIROYAL Ltd 23 Aug 1974 [28 Aug 1973] 37104/74 Headings C3R and C3P [Also in Division B5] A liquid mixture comprises a polymerizable ethylenically unsaturated resinous esterification product dissolved in a copolymerizable vinyl monomer, said product being the reaction product of (A) a polyol which is a reaction product of a novolak resin and 1-1À2 moles of an alkylene oxide per phenolic hydroxyl group in the novolak, and (B) an entirely monocarboxylic acid material selected from (a) an alpha, betaethylenically unsaturated monocarboxylic acid, and (b) a mixture of (a) with up to 10% wt., based on (a), of a saturated or aromatic monocarboxylic acid having a boiling point at least as high as the boiling point of (a). Polyol (A) preferably has the formula and acid (a) the formula CH 2 =C(R)COOH where R and R<SP>1</SP> are hydrogen or alkyl, R<SP>11</SP> is hydrogen or aryl, X is C 1 -C 3 alkyl or halogen, n= 1-10 and m=0-2. The preferred vinyl monomer is styrene. The above liquid mixture may be prepared by dissolving polyol (A) and monocarboxylic acid (B) in an inert organic solvent which forms an azeotrope with water and has a boiling point of from 80-130‹ C., e.g. benzene or toluene, containing a strong acid as esterification catalyst, e.g. H 2 SO 4 or p-toluene sulphonic acid, and a phenolic inhibitor of freeradical polymerization; e.g. t-butyl catechol, hydroquinone or the monomethyl ether thereof, and then heating to reflux temperature, removing the water of esterification, and solvent therefrom and dissolving the residue in a copolymerizable vinyl monomer, then neutralizing the catalyst preferably with anhydrous potassium carbonate, at elevated temperature, and removing the resulting insoluble material, the amount of solvent used being 100-400 mol. per gram-mole of (A), and the amount of inhibitor being from 100-600 p.p.m. based on the weight of the product. In an embodiment the amount of unsaturated monocarboxylic acid (a) used is from 10-20% in stoichiometric excess of that required to react with polyol (A) and an alkylene oxide is added to neutralize the excess of acid (a) thereby converting it into a hydroxyalkylated ester which acts as a copolymerizable monomer in the resulting mixture. Suitable acids (a) are acrylic, methacrylic and ethacrylic acid. Suitable saturated or aromatic monocarboxylic acids are propionic, butyric, valeric, benzoic and toluic acids. The addition copolymer may include a reinforcing filler, e.g. glass fibre. In Examples 1-3 an unsaturated resinous product is prepared by alkylating a phenolformaldehyde novolak resin with propylene oxide in the presence of benzyltrimethylammonium hydroxide, then esterifying the resulting product with methacrylic acid in the presence of H 2 SO 4 and hydroquinone using toluene as solvent, then neutralizing with anhydrous potassium carbonate. The product is dissolved in styrene and cured either with benzoyl peroxide at elevated temperature or with cumene hydroperoxide and manganese octoate at room temperature and subsequently heat-treated. In similar Example 6 propylene oxide is used to neutralize excess methacrylic acid. Similar examples are described using p-bromo-phenol- HCHO novolak, phenolbenzaldehyde novolak or p-oresol-HCHO novolak. In Example 13 copolymers are prepared from the unsaturated polyester resin of Example 1 and any one of the following monomers: acrylonitrile, methyl methacrylate, methyl acrylate, isobutyl methacrylate, lauryl methacrylate, triallyl cyanurate and chlorostyrene. Uses.-Castings, laminates, impregnants and coatings.