Abstract: Processes for recovering natural rubber from an aqueous natural rubber latex that contains extractables and one or more additives and that is essentially free of lignocellulosic plant material are described. Natural rubber in the latex is separated from the water. Preferably, the amount of non-rubber extractables in the natural rubber is reduced by one or more extraction steps yielding a dried natural rubber.

Abstract: Disclosed is a method and apparatus for the extraction of high molecular weight biopolymers from plants. Specifically, invention described herein relates to the commercial processing of plant material, including that from desert plants native to the southwestern United States and Mexico, such as the guayule plant (Parthenium argentatum), for the extraction of biopolymers, including natural rubbers. More specifically, the invention relates to laboratory to commercial scale extraction of high molecular weight biopolymers from plant materials including the chemical and mechanical processing of the plants and purification of the extracted biopolymer.

Abstract: A method of preparing a low allergic natural rubber latex which is less likely to cause allergy, comprising adding a protease having an exopeptidase activity to a natural rubber latex and aging the natural rubber latex, thereby to decompose a protein in the latex to such a degree that the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or more, are not detected; a method of preparing a deproteinized natural rubber latex which is less likely to cause allergy, comprising adding an alkali protease to a natural rubber latex, thereby to decompose a protein in the latex, adding a protease having an exopeptidase activity, thereby to further decompose the protein and a decomposition product thereof in the latex, and removing the protein and the decomposition product thereof; a low allergic natural rubber obtained by a decomposition treatment of a protein, wherein the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or m

Abstract: A process for working up polymer components prepared by emulsion polymerization is disclosed. The process is characterized in that coagulation of the aqueous polymer latex present after emulsion polymerization is performed using a combination of A) an aqueous solution of at least one salt selected from the group consisting of sodium chloride, calcium chloride, magnesium chloride, aluminum chloride, sodium sulfate, magnesium sulfate and aluminum sulfate, B) an aqueous solution of at least one salt of an acid selected from the group consisting of hypophosphorous acid (H3PO2), phosphorous acid (H3PO3 or HPO2) and ascorbic acid and optionally C) an aqueous dilute acid selected from the group consisting of sulfuric acid, phosphoric acid and acetic acid.

Abstract: Described is a process for reducing the antigenicity of sap and products made from the sap of the Hevea brasilisensis plant and other rubber plants. The process involves contacting sap or a latex rubber product with a mono or dialdehyde, a semialdehyde or any chemical containing an aldehyde group, to cross-link antigenic proteins within the sap or the latex product. The cross-linked proteins no longer have the capability to cause an allergic reaction to persons coming into contact with the latex products made by the process of the invention. The cross-linking reaction between the proteins in the latex sap and the aldehyde can take place in the solution used to the final product, or after the final latex product has been formed, or during various intermediate steps of the processes for forming the latex products.

Abstract: The present invention relates to a latex with modified surface chemistry, which may be obtained by carrying out a free-radical emulsion polymerization in the presence of at least one ethylenically unsaturated monomer or at least one polymer containing residual ethylenically unsaturated bonds,of at least one free-radical polymerization initiator,of at least one water-soluble and/or water-dispersible monoblock, diblock or triblock polymer comprising at its end an active group capable of forming a radical, chosen from dithioesters, xanthates, thioether-thiones and diothiocarbamates. The invention similarly relates to redispersible powders that may be obtained by drying the said latices.

Abstract: Disclosed are a cationic deproteinized natural rubber latex, in which rubber particles are positively charged and the concentration of said rubber particles is from 40 to 65% by weight and that the viscosity at 25° C. of said latex is 200 mPa·s or less, a method of preparing said latex which comprises subjecting to a deprotenization treatment using a proteolytic enzyme and a deproteinizing agent made of one or more surfactant selected from cationic and nonionic surfactants, and optionally adding a post additive comprising a cationic or nonionic surfactant as an active component, thereby to enable both surfactants described above to coexist, and a treating agent used in the same.

Abstract: A method of preparing a low allergic natural rubber latex which is less likely to cause allergy, comprising adding a protease having an exopeptidase activity to a natural rubber latex and aging the natural rubber latex, thereby to decompose a protein in the latex to such a degree that the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or more, are not detected; a method of preparing a deproteinized natural rubber latex which is less likely to cause allergy, comprising adding an alkali protease to a natural rubber latex, thereby to decompose a protein in the latex, adding a protease having an exopeptidase activity, thereby to further decompose the protein and a decomposition product thereof in the latex, and removing the protein and the decomposition product thereof; a low allergic natural rubber obtained by a decomposition treatment of a protein, wherein the protein and a protein decomposition product, which have a number-average molecular weight of 4500 or m

Abstract: A puncture sealing agent for sealing an inner surface of a tire comprises a deproteinized rubber latex that is formed by removing protein from a natural rubber latex. The puncture sealing agent includes nitrogen content at 0.1 wt. % or less of rubber solid content of the deproteinized rubber latex, and ammonia content at 0.5 wt. % or less of the rubber solid content.

Abstract: A process for producing a natural rubber for a pressure-sensitive adhesive, which comprises decreasing a molecular weight of an unmasticated natural rubber by the action of a peptizing agent while dissolving the unmasticated natural rubber in an organic solvent, and a natural rubber-based pressure-sensitive adhesive composition comprising a natural rubber having a weigh average molecular weight Mw of 700,000 or less obtained by the process.

Abstract: Disclosed are a deproteinizing agent comprising a proteolytic enzyme and one or more cationic surfactants selected from the group consisting of an alkylamine salt, an alkylamine derivative and quaternized compounds thereof; and a method of preparing a cationic deproteinized natural rubber latex, which comprises adding said deproteinizing agent to a field latex or an ammonia-treated latex thereby subjecting the latex to a deproteinization treatment and purifying the rubber particles in the latex.

Abstract: A method for producing a formed product of deproteinized natural rubber latex capable of reducing a content of an allergen in a natural rubber latex material to a level sufficient to keep the latex from being harmful to the human body without decreasing yields of the product and deteriorating formability of the latex. In the method, cleaning removal of a non-rubber content is carried out after each of protein decomposition, prevulcanization and forming. An aqueous alkali solution, ammonia, water containing free chlorine in an amount of 0.005 to 0.02% by weight or alcohol-water mixed liquid containing alcohol in an amount of 5 to 80% by weight is used as cleaning liquid for the cleaning removal. The method is suitably applied to production of a natural rubber product such as a rubber glove, a condom, a catheter, a foam rubber material and the like.

Abstract: Reduced allergenicity natural rubber latex articles having otherwise normal physical, mechanical, and chemical properties are produced by directly sequestering the antigenic components on one surface of the article followed by inducing the remaining antigenic components of the natural rubber latex to bloom onto and adjacent to the opposed surface of the article prior to treatment with a subsequent screening reagent to sequester the remaining antigenic compounds.

Abstract: Reduced allergenicity natural rubber latex articles having otherwise normal physical, mechanical, and chemical properties are produced by inducing the antigenic components of the natural rubber latex to bloom onto and adjacent to the tissue contacting surface of the article prior to treatment with a screening reagent to sequester the antigenic regions.

Abstract: A method of making pigment concentrate particles having pigment uniformly dispersed in a polymer and exhibiting a controlled morphology and narrow particle size distribution. The method involves dispersing pigment particles in a pigment dispersant liquid to form a first dispersion phase; blending the first dispersion phase with a binder to produce a second dispersion phase; mixing the second dispersion phase under sufficient shear to produce a suspension of small dispersion phase droplets in an immiscible suspending liquid; allowing the small dispersion phase droplets in the suspension to coalesce to a larger size at which substantially no further coalescence can occur; mixing the suspension of coalesced droplets with an extracting liquid to remove the pigment dispersant liquid from the coalesced droplets; and isolating the resulting pigment concentrate particles.

Abstract: Improved water-based latex compositions are provided comprising a water-based latex emulsion and boric acid. It has been surprisingly found that by adding boric acid to water-based latex emulsions known in the art, micro-organism growth is eliminated. In a preferred composition, the boric acid is present in an amount of about 0.10% to about 10% by weight of the total composition.

Abstract: A process for achieving a significant reduction in the volatile organic compound content (VOC) of an aqueous polymerization system includes the steps of contacting the aqueous polymerization system with an organic solvent and allowing said organic solvent to be absorbed into polymer particles of said aqueous polymerization system, contacting said aqueous polymerization system and organic solvent with a gas or vapor at temperature and pressure conditions which cause mass transfer of the volatile organic compounds from said latex into said gas or vapor phase, and separating said gas or vapor from said aqueous polymerization system. The solvent is generally absorbed into the polymer particles of the latex and serves as a stripping aid, especially with respect to higher molecular weight compounds which tend to remain trapped in the polymer particles during conventional stripping processes.

Abstract: A limited coalescence method of making polymer particles having an average particle size of 3 .mu.m or less comprising dispersing the polymer particles in an organic liquid diluent after they are separated from the aqueous suspension medium in which they are prepared, to thereby eliminate or substantially avoid agglomeration between the polymer particles upon drying.

Abstract: A process for culturing bacteria is disclosed in which is utilized as a bacterial nutrition a serum byproduced upon treatment of a natural rubber latex. The serum has an ample supply, a low cost, a stable quality and a sufficient activity over a wide variety of bacteria, thus contributing to accelerative growth for aerobic and anaerobic bacteria.

Abstract: A dry nonelectroscopic toner surface coated with 3 to 40% by weight of an organofunctional substituted fluorocarbon compound. Toners of the invention are useful for developing photosensitive elements having imagewise tacky and complementary nontacky image areas. The surface coating imparts good toning and clean-up characteristics, together with improved performance on aging.

Abstract: Suspension stabilizer particles are removed from the surface of polymer particles formed in a limiting coalescence formation technique by dissolving in a solution containing a fluoralkyl polyether surface active agent.