Process to produce polyvinyl-ester compositions with low residual monomer and the use thereof
A process for reducing the amount of residual monomer in aqueous polymerization emulsion by using a sequential polymerization steps, The first step consists in adding an emulsion, of vinyl ester of alkyl of C1 to C18 carboxylic acids, to water containing a radical initiator, the second step consists in adding further an emulsion of alkyl acrylate and/or methacrylate, and the third step consists in c) adding to polymeric emulsion, resulting of the steps a) and b), pure liquid acrylate or methacrylate with alkyl chain of C 1 to C 12 .
1. A process for reducing the amount of residual vinyl ester monomer in a vinyl ester-acrylate co-polymeric emulsion by using sequential polymerization steps consisting essentially of:
a) adding a pre-emulsion consisting essentially of monomers of vinyl ester of alkyl of C1 to C18 carboxylic acids to water containing a radical initiator;
b) adding to a) a pre-emulsion consisting essentially of monomers of alkyl acrylate, an emulsion consisting essentially of monomers of alkyl methacrylate, or a combination thereof to form a polymeric emulsion; and
c) adding to the polymeric emulsion one or more monomers of liquid acrylates, methacrylates, or combinations thereof, wherein each of the one or more liquid acrylates or methacrylates monomers comprise an alkyl chain of C1 to C16, and forming the vinyl ester-acrylate co-polymeric emulsion, wherein the vinyl ester-acrylate co-polymer is a co-polymer of vinyl ester monomers and acrylate monomers, methacrylate monomers, or combinations thereof.
2. The process of claim 1 , wherein the vinyl ester of alkyl of C1 to C18 carboxylic acids consists of a linear alkyl chain, from 3 carbon atoms as a branched alkyl chain, from 5 carbon atoms as a branched tertiary alkyl chain, or a mixture thereof.
3. The process of claim 2 , wherein the vinyl ester of alkyl of C1 to C18 carboxylic acids is vinyl propionate, vinyl n-butyrate, vinyl laurate, vinyl ester of 2-ethyl hexanoic acid, vinyl caprate, and vinyl stearate, vinyl neodecanoates, vinyl pivalate or a mixture thereof.
4. The process of claim 1 , wherein the monomers of alkyl acrylate or alkyl methacrylate are reaction products of ethylenically unsaturated carboxylic acids and C1 to C20 alcohols.
5. The process of claim 4 , wherein the monomers of alkyl acrylate or alkyl methacrylate are selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, 2-propyl heptyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, 4-tertbutylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate or a mixture thereof.
6. The process of claim 1 , wherein the monomers of alkyl acrylate or the alkyl methacrylate of c) is selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate or a mixture thereof.
7. The process of claim 3 , wherein the vinyl ester of alkyl of C1 to C18 carboxylic acids is a vinyl ester of neodecanoic acids.