| 摘要 |
A polyester is derived from a telomer of M.W. 400-2000 containing 3-12 carboxyl group or corresponding anhydride groups per molecule, a dicarboxylic acid and a diol. Both acid and anhydride groups may be present in the same telomer. The telomer may be produced from maleic anhydride, acrylic acid, methacrylic acid, itaconic acid, maleic acid or mono esters of maleic acid, e.g. those of alcohols of 1-6 carbon atoms or ethylene glycol monoethers of 3-6 carbon atoms. Ethylenically unsaturated compounds not containing carboxyl groups may also be used, e.g. styrene, ethylene, propylene, butylene, methyl methacrylate, diiso butylene, and a-methyl styrene. The telomers may be produced at 140-200 DEG C. at superatmospheric pressure and in the presence of 0.5-5% catalyst. A telogen having a secondary or tertiary carbon atom, e.g. cumene, diethylbenzene, diisopropyl benzene and triisopropylbenzene, which also acts as a solvent is heated and the monomers and peroxide initiator catalyst added. Telomers containing carboxyl groups may also be prepared by hydrolysis or alcoholysis of telomers containig ester or acid anhydride groups. In the polyester forming mixture the overall ratio of carboxyl to hydroxyl groups may be 1 : 1-1.5. 20-85% of the carboxyl groups may originate from the telomer and at least 15% may originate from the dicarboxylic acid. The dicarboxylic acid may be aromatic or aliphatic and have 2-10 carbon atoms or anhydrides thereof may have 4-10 carbon atoms. Acids and anhydrides specified are ortho-, iso and terephthalic, maleic adipic and sebacic acids and orthophthalic and maleic anhydrides. The diol may be aliphatic or cycloaliphatic of 2-8 carbon atoms, e.g. ethylene, propylene, butylene and hexylene glycols, propane - 1,2 - diol, butane - 1,3 - diol, 2,2-dimethylpropane - 1,3 - diol and 1,4 - bishydroxymethyl cyclohexane. Mixtures of acids and/or diols may be used. Up to 20% of the carboxyl groups and/or hydroxyl groups may be provided by acids or alcohols containing 1 or 3-6 carboxyl or hydroxyl groups. Compounds specified are linseed oil fatty acids, benzoic acid, citric acid, mellitic acid, pyromellitic acid dianhydride, butanol, dodecyl alcohol, ethylene glycol monobutyl ether, glycerol and trimethylol propane. The esterification may be at 100-190 DEG C. in the presence of a catalyst, e.g. copper acetate or a salt of Zn, Fe, Zr or Mn2+. The eliminated water may be removed by distillation, azeotropic distillation with toluene or xylene or in a stream of inert gas, e.g. N2. The product may have an acid number of 40-140 and a hydroxyl number of 75-400. It may be cooled to 60-95 DEG C., neutralized with ammonia or an amine and diluted with water. Amines specified are mono-, di- and trimethylamine triethylamine, butylamine, ethanolamine, diethylethanolamine and up to 5% stearylamine. After neutralization and dilution any remaining solvent may be distilled out. The product may be used as an adhesive, impregnating agent or lacquer. It may be made into a film or stuck on metal sheets. It may be pigmented. In Example (5) a composition comprises a 50% polyester solution, Fe2O3, magnesium silicate and BaSO4. In Example (8) tri-b-hydroxyethylborate is present in the esterification step. |
