| 摘要 |
<p>1,203,524. Emulsion polymerization process. CELANESE CORP. 1 Aug., 1968 [2 Aug., 1967; 30 April, 1968], No. 36675/68. Heading. C3P. A process for the production of a high solids aqueous polymer emulsion comprises preparing an aqueous pre-emulsion of at least one polymerizable monomer containing at least one ethylenically unsaturated group which is capable of forming, in the presence of a suthcient amount of at least one surfactant, a stable preemulsion and subsequently a stable latex polymer, said pre-emulsion containing water in an amount ranging from 6 to 25 weight per cent based on the total monomer present in said preemulsion, adding said pre-emulsion incrementally or continuously to a reaction medium comprising a portion of water, not required for forming said pre-emulsion but necessary to obtain the solids content desired in the finished product, maintaining said reaction medium at a temperature to initiate and continue the polymerization reaction and controlling the rate of said addition of said pre-emulsion to provide substantially complete conversion of said monomer or monomers to latex polymer, said polymerization being conducted in the presence of a sufficient amount of a free radical polymerization catalyst to provide substantially complete monomer conversion to produce a latex having total solids in the range from 50 to 75 weight per cent. Any anionic and/or non- ionic surfactant can be used in preparing the monomer pre-emulsion, which may also include a protective colloid. Polymerization is preferably effected with an initiator such as hydrogenperoxide, alkali metal and ammonium persulphates, perphosphates, perchlorates and perborates, azobisisobutyronitrile, t - butyl hydroperoxide and redox systems. In examples the following are polymerized (a) ethyl acrylate and methyl methacrylate, (b) vinyl acetate, ethyl acrylate and dioctyl maleate, (c) vinyl acetate, and (d) vinyl acetate and dioctyl maleate. The high solids polymer emulsions prepared in the above manner are useful in paint compositions, in the continuous production of films, in the production of elastomers, cross-linkable sealants and adhesives, in making foams, and in emulsion spinning processes.</p> |
