US 4,791,162 AGranted

Preparation of large particle size monodisperse latexes

AssigneeLehigh University

InventorsJohn W. Vanderhoff, Fortunato J. Micale, Mohamed S. El-Aasser, Chi-Ming Tseng

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Abstract

Monodisperse latexes of at least 2-30 microns particle size are prepared from an emulsion recipe comprising a monodisperse seed latex polymer on the order of 2 microns or less particle size, a polymerizable monomer, an initiator, at least one inhibitor, and a water-soluble polymeric emulsifer of 10.sup.4 -10.sup.7 molecular weight. Optional ingredients are cross-linking monomer, oil-soluble inhibitor if the mixture is to be stored before polymerization, and one or more additional emulsifiers selected from a water-soluble comonomer or polymer of 0.3.times.10.sup.3 -5.times.10.sup.3 molecular weight and a non-polymeric anionic emulsifier. Additional particle size growth and monodisperse latex yield are realized by polymerization in a microgravity environment.

Claims18

Dependent claims

A method of preparing a monodisperse latex having an average particle size of at least 2-30 microns, which comprises polmerizing a mixture of:

(A) about 2-30 parts by weight of a monodisperse seed latex polymer of particle size on the order of 2 microns or less, said seed latex polymer containing a non-polymeric anionic emulsifier;
(B) about 10-50 parts by weight of a polymerizable, non-crosslinking monomer component selected from vinyl aromatic monomers and mixtures of vinyl aromatic monomers and different ethylenically unsaturated monomers;
(C) 0 to about 0.1 parts by weight of a polyethylenically unsaturated crosslinking monomer;
(D) about 0.01-0.2 parts by weight of an oil-soluble, sparingly water-soluble free radical initiator;
(E) about 0.001 to 0.1 parts by weight of at least one water-soluble of partially water-soluble and oil-soluble free radical inhibitor;
(F) an emulsifier component comprising:
(i) about 0.05-2.0 parts by weight of a first water-soluble polymeric emulsifier of molecular weight of about 10.sup.4 -10.sup.7 selected from at least one of:
a polyvinyl pyrrolidone in the presence of a water-soluble carboxylic oligomer emulsifier of molecular weight of about 0.3.times.10.sup.3 -5.times.10.sup.3,
a 95.0-99.8% nonionic hydrophilic backbone monomer/0-2.0% hydrophobic monomer/0.2-3.0% ionic monomer copolymer,
a polyacrylamide, and
a hydroxyethyl cellulose;
(ii) 0 to about 0.05 parts by weight of a second water-soluble comonomeric or polymeric emulsifier of molecular weight of about 0.3.times.10.sup.3 -5.times.10.sup.3 ;
(iii) 0 to about 0.01 parts by weight of a non-polymeric anionic emulsifier;
and
(G) the balance being water, to make 100 parts by weight of total mixture.

12 more elements

Dependencies are inferred from the claim text.