摘要:
A method for making an aqueous polymodal synthetic resin dispersion by the emulsion polymerization of an ethylenically unsaturated monomer difficultly soluble in water, or a mixture of such monomers forming a polymer which is water insoluble under the conditions of polymerization, in an aqueous phase containing an emulsifier and a water soluble polymerization initiator, which method comprises adding a seed latex to the polymerization mixture in the course of the emulsion polymerization before more than 40 weight percent of said monomers have been polymerized, the particles of said seed latex being smaller by a factor ranging from 2 to 15 than are particles already formed by emulsion polymerization, the amount by weight of the particles in the seed latex being not greater than 10 percent by weight of the monomers and the ratio by weight of particles of said seed latex to the weight of the monomers already polymerized being from 1:4 to 1:500.
摘要:
What is disclosed is making highly concentrated, bimodal, aqueous synthetic resin dispersions by the emulsion polymerization of ethylenically unsaturated monomers, in the presence of emulsifiers and free radical-forming initiators, by adding to a first latex containing a first dispersed synthetic resin and an aqueous phase, a second latex containing a second dispersed synthetic resin and an aqueous phase and a monomer phase containing a free-radically polymerizable monomer, and then polymerizing the monomer, the average size of the particles of said first resin differing by a factor between 2 and 15 from that of the particles of second resin, the total weight of the resins and monomers representing 100 parts by weight, and the total weight of the aqueous phases representing not more than 70 parts by weight.
摘要:
Polymer powders comprising aggregated polymer particles, said powders having a low content of fines and being suitable as processing aids in the manufacture of polyvinyl chloride, are made by spray drying an aqueous dispersion (latex) of two emulsion polymers, one of which has a dynamic glass transition temperature above 90.degree. C. and the other of which has a dynamic glass transition below 105.degree. C., the latter being at least 10 K. degrees below the former.
摘要:
An emulsion polymer comprising a hard nonelastomeric core, an elastomeric intermediate stage produced in the presence of the core and essentially composed of an acrylic ester and a crosslinking monomer which contains three or more acrylic or methacrylic groups in the molecule, and a hard nonelastomeric final stage produced in the presence of the elastomeric intermediate stage and crosslinked therewith, said polymer being useful as an impact strength modifying agent which, in admixture with a thermoplastic polymethyl methacrylate molding compound for example, yields molded articles exhibiting reduced susceptibility to stress whitening and improved impact strength.
摘要:
A high surface area system is provided with latex particles for immobilization of substances containing nucleophilic groups. The high surface area system is formed by aggregating the latex particles or by bonding the latex particles to a porous support of high surface area. The latex particles contain groups such as oxirane groups that react with the nucleophilic groups. The substances containing nucleophilic groups may be enzymes or proteins such as albumin, immunoglobulins, blood-clotting factors, cell-membrane proteins or peptide hormones. The high surface area system may be used as a sorbent in removing pollutants, as a stationary phase in organic synthesis such as peptide synthesis, and in the therapeutic treatment of a patient.
摘要:
Polymer particles dispersible to form a latex and latices of such polymer particles, said particles being adaptable to the fixing or bonding thereto of a biologically active substance and having a core-shell construction wherein the polymer material of the core determines the stability of the form of the latex particles and their redispersibility, and the material of the shell(1) is so hydrophilic that it would be completely or largely water soluble if it were not anchored to the core material and/or crosslinked,(2) contains functional groups which are suitable for the covalent fixation or bonding of biological active substances, and(3) in an anhydrous condition has a T.sub..lambda.max from 20.degree.-250.degree. C., depending on its composition, and methods for bonding a biologically active substance to such particles, for example to prepare a diagnostic reagent.
摘要:
What are disclosed are a method for the reinforcement of a fibrous article with an aqueous dispersion of a resin, free of formaldehyde and acrylonitrile, comprising at least 40 weight percent of alkyl acrylates and/or methacrylates having at least 4 carbon atoms in the alkyl group; up to 57 weight percent of alkyl acrylates or methacrylates having not more than 3 carbon atoms in the alkyl group, or of styrene; less than 1 weight percent of acrylic acid or of methacrylic acid; and from 3 to 15 weight percent of a hydroxyalkyl ester of an unsaturated carboxylic acid, as well as reinforced fibrous articles made by this method and distinguished by high wet strength and by low loss of the resin binder on washing with boiling water.
摘要:
Polymer particles dispersible to form a latex and latices of such polymer particles, said particles being adaptable to the fixing or bonding thereto of a biologically active substance and having a core-shell construction wherein the polymer material of the core determines the stability of the form of the latex particles and their redispersibility, and the material of the shell(1) is so hydrophilic that it would be completely or largely water soluble if it were not anchored to the core material and/or crosslinked,(2) contains functional groups which are suitable for the covalent fixation or bonding of biological active substances, and(3) in an anhydrous condition has a T.sub..lambda.max from 20.degree.-250.degree. C., depending on its composition, and methods for bonding a biologically active substance to such particles, for example to prepare a diagnostic reagent.
摘要:
What are disclosed are aqueous dispersions of a self-crosslinking synthetic resin, said dispersions consisting of an aqueous phase containing from 0.2 to 5 weight percent of urea and, dispersed therein, resin particles formed of a vinyl polymer comprising (a) from 52.1 to 97.9 weight percent of acrylate or methacrylate esters, vinyl esters, or styrene; (b) from 0.1 to 10 weight percent of N-methylol acrylamide or methacrylamide; (c) from 2 to 10 weight percent of an hydroxyalkyl ester of an unsaturated carboxylic acid; and (d) 0 to 27.9 weight percent of other monomers, which dispersions, on drying and condensation to form films, liberate much less formaldehyde than comparable dispersions without urea while retaining good solvent resistance.
摘要:
What are disclosed are aqueous dispersions of an acrylic resin which is suitable for the reinforcement of fibrous articles and is free of formaldehyde and acrylonitrile, said resin comprising (a) from 70 to 96.95 weight percent of alkyl esters of acrylic acid and/or methacrylic acid, or mixtures of such esters with styrene; (b) from 2 to 30 weight percent of an hydroxyalkyl ester of an unsaturated carboxylic acid; (c) from 1 to 10 weight percent of acrylamide or of methacrylamide; (d) from 0.05 to 3 weight percent of a crosslinking comonomer having at least two polymerizable double bonds; (e) up to 5 weight percent of an unsaturated carboxylic acid; and (f) up to 20 weight percent of one or more further monomers, as well as fibrous articles reinforced with such a resin dispersion and showing reduced loss of resin binder on dry cleaning and reduced absorption of plasticizers, and methods of making such articles.