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US 4,056,501 AGranted
Cationic structured-particle latexes
AssigneeThe Dow Chemical Company
InventorsDale S. Gibbs, Earl H. Wagener, Ritchie A. Wessling
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AssigneeThe Dow Chemical Company
InventorsDale S. Gibbs, Earl H. Wagener, Ritchie A. Wessling
Estimating the term…
Structured-particle latexes are prepared from nonionic or slightly cationic latexes, either preformed or polymerized in situ, by emulsion polymerizing monomeric materials which include an ethylenically unsaturated, activated-halogen monomer such as vinylbenzyl chloride in the absence of a sufficient amount of a surfactant to initiate new particles whereby the activated-halogen monomer is copolymerized on the surface of the existing particles which are dispersed in an aqueous media. The resulting structured-particle latex may then be reacted with a nucleophile such as dimethyl sulfide or trimethyl amine to form a latex having stabilizing "onium" groups such as sulfonium groups or quaternary ammonium groups chemically bound at or near the surface of the polymer particles which are dispersed in aqueous media. The cationic latexes are suitable for coatings and organic pigments.
A method for preparing a cationic structured-particle latex comprising the steps of reacting at a temperature from about 0.degree. to about 80.degree. C a water-stable, nonionic nucleophile which is capable of diffusing through aqueous media with a latex of copolymer particles having activated halogens bound to a thin layer of the copolymer at or near the particle surface;
An aqueous colloidal dispersion of cationic structured-particles of polymer consisting of a nonionic, organic polymer core encapsulated by a thin layer of a water-insoluble organic copolymer having pH independent cationic groups chemically bound to the organic copolymer at or near the particle surface;
Dependencies are inferred from the claim text.
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Chemical or physical treatment of rubber latex before or during concentration: preservation of rubber latex
Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to
Treatment or chemical modification of rubbers
Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
Term ended 1 Nov 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The invention is concerned with latex compositions and with methods for the preparation of such latexes. The polymer particles comprising the latex have stabilizing, pH independent ions chemically bound at or near the surface of the particles.
2. Description of the Prior Art
The following examples illustrate ways in which the present invention can be practiced, but should not be construed as limiting the invention. All parts and percentages are by weight unless otherwise expressly indicated. The particle sizes shown in the examples are average particle diameters obtained by light scattering measurements, except as indicated.
A thermoplastic acrylic latex is prepared in the following manner. A monomer mixture is prepared from 1072 grams of ethyl acrylate and 528 grams of methyl methacrylate and to this mixture is added 24 grams of dodecanethiol and 5 grams of an 82.7-percent solution of t-butyl hydroperoxide to form a monomer feed solution. A seed latex is prepared from 750 grams of a surfactant solution previously prepared by stirring 710 grams of water and 40.0 grams of a 25-percent-active solution of dodecylbenzyldimethylsulfonium chloride for 2 hours under a stream of nitrogen to which is then added 25 grams of the monomer feed solution, followed by a continuously-added reducing stream pumped for about 2 hours at a rate of 7.67 grams per hour, the stream being a portion of a solution previously prepared from 9 grams of hydroxylamine hydrochloride diluted to 500 grams with deionized water. To the seed latex is added monomer feed solution at a rate of 55 grams per hour with continuation of a reducing stream of the same rate of addition and composition as in the seed latex and concurrently pumping into the reaction mixture at the rate of 20 grams per hour a surfactant solution previously prepared from 400 grams of deionized water and 100 grams of a 25-percent-active solution of dodecylbenzyldimethylsulfonium chloride. After 20 hours the conversion is about 85 percent, the continuous additions are discontinued, 15 grams of vinylbenzyl chloride is added and the reaction is allowed to continue for an additional 2 hours. The temperature is maintained at 50.degree. C throughout the reaction. There is obtained thereby a latex (C-1) having a solids content of 47.6%, a pH of 2.8, a particle size of 1250 Angstroms, and containing a polymer having a molecular weight of 74,000 with a chloride ion content of 0.113 milliequivalent per gram of polymer.
A portion of Latex (C-1) is diluted with water to a solids content of 23.8%, then 2.12 parts of trimethylamine per 100 parts of the diluted latex are added with gentle stirring and the resulting mixture is allowed to stand at room temperature for 5 days. A latex (I-A) is obtained containing 0.242 milliequivalent of total charge per gram of polymer of which 0.129 milliequivalent is present from quaternary ammonium groups bound to each gram of polymer in the latex.