Emulsion copolymer cation exchange resins
AssigneeRohm and Haas Company
InventorBerni P. Chong
Life of this patent
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Abstract
Emulsion copolymer particles with diameters smaller than 1.5 micrometers and functionalized with cation exchange functional groups are prepared and suspended as emulsions in liquid media to form liquid cation exchange materials.
Claims16
A liquid cation exchange material comprising an emulsion of submicroscopic, approximately spherical beads of previously isolated, crosslinked emulsion copolymer having diameters within the range from about 0.01 to about 1.5 micrometers, and bearing from about 0.7 to about 1.5 cation exchange functional groups per monomer unit, the cation exchange functional groups being selected from the group consisting of strongly acidic functional groups and the free acid form of weakly acidic functional groups.
A process for preparing submicroscopic cation exchange resin particles comprising approximately spherical beads of crosslinked copolymer having diameters within the range from about 0.01 to about 1.5 micrometers and bearing from about 0.7 to about 1.5 strongly acidic cation exchange functional groups per monomer unit, which process comprises the steps of:
- (a) emulsion polymerizing a mixture of a major amount of a monoethylenically unsaturated monomer and a minor amount of a polyethylenically unsaturated monomer to form an emulsion of crosslinked copolymer beads,
- (b) adding the emulsion to a coagulant liquid to form coagulum particles of the copolymer beads,
- (c) separating the coagulum particles, from the emulsion polymerization medium,
- (d) functionalizing the coagulum particles with strongly acidic cation exchange functional groups, and
- (e) subsequently resuspending the coagulum of copolymer beads in a liquid medium to form an emulsion.
A process for preparing submicroscopic cation exchange resin particles comprising approximately spherical beads of crosslinked copolymer having diameters within the range from about 0.01 to about 1.5 micrometers and bearing from about 0.7 to about 1.5 weakly acidic cation exchange functional groups per monomer unit, the weakly acidic groups being in the free acid form, which process comprises the steps of:
- (a) emulsion polymerizing a major amount of an acrylic ester monomer and a minor amount of a polyethylenically unsaturated monomer to form an emulsion of crosslinked acrylic copolymer beads,
- (b) hydrolyzing the ester linkages of the acrylic copolymer beads with a strong acid to form carboxylic cation exchange functional groups in the free acid form, and to concurrently form a coagulum of the functionalized copolymer beads, and
- (c) resuspending the coagulum of functionalized copolymer beads to form an emulsion of the functionalized copolymer beads.
A process for preparing submicroscopic cation exchange resin particles comprising approximately spherical beads of crosslinked copolymer having diameters within the range from about 0.01 to about 1.5 micrometers and bearing from about 0.7 to about 1.5 weakly acidic cation exchange functional groups per monomer unit, the weakly acidic groups being in the free acid form, which process comprises the steps of:
- (a) emulsion polymerizing a major amount of an acrylic ester monomer and a minor amount of a polyethylenically unsaturated monomer to form an emulsion of crosslinked acrylic copolymer beads,
- (b) hydrolyzing the ester linkages of the acrylic copolymer beads with an alkali hydroxide to form carboxylic cation exchange functional groups in the alkali salt form, and
- (c) contacting the emulsion of functionalized copolymer beads with strongly acidic cation exchange resin in the free acid form, to convert the functionalized emulsion copolymer beads in the emulsion to the free acid form.
A method for the removal of anionic impurities from a liquid containing such impurities which comprises contacting the liquid with an emulsion of submicroscopic, approximately spherical beads of crosslinked emulsion copolymer having diameters within the range from about 0.01 to about 1.5 micrometers, and bearing from about 0.7 to about 1.5 cation exchange functional groups per monomer unit.
Dependencies are inferred from the claim text.