| 摘要 |
<p>1292883 Aqueous resin dispersions ROHM GmbH 27 Feb 1970 [1 March 1969] 9684/70 Heading C3P Aqueous synthetic resin dispersions which are resistant to frost and electrolytes are prepared by emulsion copolymerizing, in the presence of an anionic emulsifying agent, a monomer mixture comprising (A) 30-99À9% by weight of the mixture of an ethylenically unsaturated monomer capable of forming a soft homopolymer, (B) 0À1-10% by weight of a copolymerizableα,#-ethylenically unsaturated mono- or dicarboxylic acid and (C) 0-70% by weight of a copolymerizable ethylenically unsaturated monomer, and admixing the dispersion obtained with (1) a nonionic emulsifying agent comprising an alkylphenol/ethylene oxide or fatty alcohol/ ethylene oxide condensate containing 7-12 ethylene oxide units per molecule or a mixture of at least two alkylphenol/ethylene oxide condensates, each containing 6-20 ethylene oxide units per molecule and the mixture containing an average of 7-12 units of ethylene oxide per molecule, and (2) a nonionic emulsifying agent comprising an alkylphenol/ethylene oxide or fatty alcohol/ethylene oxide condensate containing at least 35 ethylene oxide units per molecule. In a preferred embodiment the monomer mixture is emulsified in an aqueous medium with part of the anionic emulsifier and preferably admixed with a portion of a free radical initiator (e.g. ammonium persulphate), and the emulsion is then added gradually to an aqueous medium containing the remainder of the anionic emulsifier and preferably a further portion of initiator, while simultaneously effecting polymerization. Monomer (A) may be an acrylate ester preferably having a C 1 -C 6 alcohol moiety, a methacrylate ester having 4 or more carbon atoms in the alcohol moiety, a vinyl ester of a carboxylic acid containing at least 4 carbon atoms or a vinyl ether. Monomer (B) may be acrylic or methacrylic acid, maleic, fumaric or itaconic acid or a hemi-ester of such a dicarboxylic acid. Monomer (C) may be a methacrylate ester of a C 1 -C 3 alcohol, preferably methyl methacrylate, or styrene, vinyl toluene,α-methylstyrene, acrylonitrile or methacrylonitrile. Suitable anionic emulsifiers are alkali metal salts of organic compounds containing a sulphonic or sulphuric acid group; particularly preferred are sulphated alkylphenol/ethylene oxide condensates.</p> |
