823 results about "Natural rubber latex" patented technology

A material for making elastomeric nitrile rubber articles is disclosed. In particular, the process and material formulation can produce nitrile rubber based articles, which exhibit force-strain characteristics that are comparable to those of natural rubber latex articles, while maintaining the tensile strength properties of nitrile rubber. The process includes an accelerator composition at the pre-cure stage having a dithiocarbamate, a thiazole, and a guanidine compound. The invention also includes an elastomeric nitrile rubber product made by the process, such as examination, surgical, or work gloves, which can have an exterior coating over naked rubber selected from either a silicone emulsion or oil, glycerin solution, a combined mixture of silicone and glycerin/glycerol, a fluorocarbon release agent, or a natural or synthetic hydrocarbon-based oil in amounts that do not degrade said substrate rubber material.

The present invention finds that a detackified natural rubber latex product can be provided by a combination of treatment with a hydrophilic group sealant, coating with a detackifying polymer, halogenation and the like. The present invention also finds that a detackified natural rubber latex product which causes no discoloration of a metallic product surface can be provided by coating it with a detackifying, carboxylated latex vulcanized without using sulfur. The present invention also finds that a detackified natural rubber latex product of controlled protein elution can be provided by chemically modifying protein present in the natural rubber latex with an anionic group, cationic group or the like.

A thin walled natural rubber latex material is disclosed suitable for forming thin walled products including gloves, dental dams and shields, catheter tubing, penrose surgical drains, finger cots, coverings for body parts, and the like. The thin walled material is formed from a latex emulsion containing natural rubber, sulphur-free, oxygen-donating curing agents, and a strength enhancing agent which may be an inorganic substance such as fumed silica and/or an organic substance such as monomers and polymers of families of acrylics and esters. The emulsion also preferably includes microcrystaline wax as an oxygen barrier, and the material is also provided with a heat resistant and water resistant coating which blocks transfer of latex proteins from the material and enhances slip of the material.

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.degree. C. of said latex is 200 mPa.multidot.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.

A composition for producing an elastomeric thin film comprising a carboxylated acrylonitrile polybutadiene latex which is vulcanized without the use of conventional sulphur and accelerators thereby reducing the possibility of contacting immediate Type I hypersensitivity and delay Type IV hypersensitivity caused by the presence of natural rubber latex proteins and accelerators respectively. The dipping process for making gloves by using a latex composition provided by: premixing carboxylated acrylonitrile polybutadiene latex with methacrylic acid, or alternatively using a self-crosslinked latex, adding zinc oxide, adjusted to 9 to 10 of the pH level, and diluted with water to obtain 18% to 30% by weight of total solid content; dipping the glove former into the composition to form a layer of thin film of the latex composition on the former; drying the thin latex film on the former and crosslinking the latex film on the former.

A modified form of a lacrosse net provides increased adherence, integrity, and “give” as a result of a coating applied to the fibers. In one form, the fibers are manually coated by brushing them with a natural latex mixture followed by evaporation of the volatile components, which gives the coated fibers a tacky and energy absorbent nature. The soft nature of the coating may also aid in dissipating energy during impact with the ball, and this could contribute to the sense of increased “feel.” There are many natural and synthetic polymers that might be capable of delivering similar benefits, including conventional synthetic elastomers, e.g., butyl rubber. Thermoplastic elastomers are a growing field of interest in coating technologies, and with the appropriate tuning, they can be made with all of the same properties as the natural rubber coating. A brush-on method delivers the desired coating thickness and properties, but other methods, such as dip coating and spray coating, may increase feasibility for scaling-up the process. In one arrangement, the entire fiber is composed of a rubbery material. The resulting properties may not be exactly what is desired, however, because the underlying integrity of the nylon fiber would be absent, and this might result in netting with a “springy” feel.

The present disclosure provides for a formula and process for making elastomeric rubber thin film articles. In particular, the formula and process is a system which produces non-Hevea or Guayule natural rubber latex (GNRL) thin film articles which have a thickness of 30-80 microns (0.03-0.08 mm), and preferably less than 40 microns (0.04 mm). These thin film articles exhibit physical strength properties similar to that of Hevea brazilensis natural rubber latex (NRL). More specifically, the disclosed thin rubber thin film articles exhibit unaged tensile strength of at least 24 MPa (about 3500 psi) and aged tensile strength of at least 19 MPa (about 2800 psi).

There are provided a modified natural rubber made from a modified natural rubber latex, in which a polar group-containing monomer is graft-polymerized to natural rubber latex, and a rubber composition comprising such a modified natural rubber and carbon black and/or silica. Also, there are provided a modified natural rubber latex in which a tin-containing monomer or an alkoxysilyl group-containing monomer is graft-polymerized to natural rubber latex and a modified natural rubber made therefrom and a rubber composition comprising such a modified natural rubber.

The invention discloses a wet smelting method for preparing a natural rubber/nanometer silicon dioxide rubber compound, which comprises the following steps of: mixing natural rubber latex with silicon sol solution to form a wet smelting system; heating the silica sol to generate condensation reaction to generate the SiO2 gel with properties, heating the wet smelting system to generate the silica sol into nanometer silicon dioxide particles in situ and uniformly dispersing the nanometer silicon dioxide particles into NR (Natural Rubber) emulsion to form the NR/ nanometer silicon dioxide rubber compound after condensation and co-precipitation; and mixing the natural rubber latex with a nanometer silicon dioxide dispersing body to form the NR/ nanometer silicon dioxide rubber compound after condensation and co-precipitation. The wet smelting method has the beneficial effects that the mass ratio of natural rubber/nanometer silicon dioxide prepared by the wet smelting method is 100/30-90, and vulcanized rubber of the nanometer silicon dioxide has excellent physical and mechanical properties and is high-quality rubber for preparing truck radial tire tread rubber with high wet skid resistance and low rolling resistance, i.e. green tire.

The present invention makes it possible (1) to produce a natural rubber wet master batch and/or a synthetic isoprene rubber wet master batch by mixing a slurry solution of biodegraded rubber powder dispersed in water with a natural rubber latex solution and/or a synthetic isoprene rubber latex solution. Further, the present invention makes it possible (2) to produce a natural rubber wet master batch and/or a synthetic isoprene rubber wet master batch by mixing a slurry solution of dispersed carbon black and/or silica and rubber powder with a natural rubber latex solution and/or a synthetic isoprene rubber latex solution. A rubber composition having high physical properties can be obtained by adding a natural rubber master batch and/or a synthetic isoprene rubber master batch obtained by drying the natural rubber wet master batch and/or the synthetic isoprene rubber wet master batch. Further, the rubber composition containing the wet master batch obtained by the method in combination of above (1) and (2) also exhibits high physical properties.

The invention discloses a preparation method of an epoxidized natural rubber masterbatch with highly dispersed nano-silicon dioxide/carbon black, which comprises the following steps: performing ultrasonic dispersion on nano-silicon dioxide modified by a silane coupling agent and carbon block after liquid phase oxidation by an oxidant by using deionized water, then adding the nano-silicon dioxide into epoxidized natural rubber latex, stirring, finally performing steam solidification or solidification by a solidifying agent, drying, and getting the epoxidized natural rubber masterbatch with the highly dispersed nano-silicon dioxide/carbon black. Compared with the mechanical properties of the masterbatch prepared by adding the same parts of the nano-silicon dioxide/carbon black powder, the mechanical properties of the masterbatch are as follows: the 100% modulus is improved from 2.3MPa to 3.1-3.4MPa, the 300% modulus is improved from 9.2MPa to 10.1-11.6MPa, the tensile strength is improved from 31.2MPa to 33.5-36.8 MPa, the elongation at break is improved from 625% to 647%-688%, and the tearing strength is improved from 48.3N/mm to 53.8-58.3N/mm; furthermore, the process is simple, and the large-scale production is easy.

The invention discloses a pair of antiskid rubber gloves and a processing method thereof. Each antiskid rubber glove comprises rubber latex forming a glove body and antiskid rubber latex forming an antiskid layer, wherein the antiskid rubber latex consists of natural rubber latex, sulfur, zinc oxide, an accelerator, an antioxidant and rubber particles. According to the antiskid rubber gloves disclosed by the invention, rubber particles are arranged on the outer surfaces of the gloves in a processing course of the gloves so as to increase the friction coefficient of the gloves, enhance the catching power of the gloves and largely improve the antiskid effect of the gloves; in addition, the gloves have no special requirement on production moulds and equipment and only the traditional production mould is needed in a production process, therefore the production input is low and the production cost of enterprises can be reduced greatly. The gloves processed with the processing method disclosed by the invention have the advantages of good antiskid effect, capability of solving the problem that defective holes possibly appear on the gloves caused by mould bumps in the production process and high yield; and the processing method disclosed by the invention has the advantage of simple operation.

The invention relates to novel cement paste for well cementation. The novel cement paste for well cementation is made from the following components of: by weight, 100 parts of hydraulic cement, 44 parts of water, 0.5-30 parts of a reversible latex powder and 0.2-0.5 parts of an antifoaming agent, wherein the reversible latex powder is prepared by spray drying of one component which can be selected from the group consisting of a natural rubber latex, SBR latex, a vinyl acetate-ethene emulsion, an organosilicon emulsion and a polyacrylate emulsion. The cement paste provided by the invention has excellent properties of controlling dehydration, preventing fluid channeling, improving mechanical properties of cement stone to prolong the endurance of the cement stone, reducing the permeability of the cement stone and raising the corrosion resistance of the cement stone. The above properties of the cement paste enable the cement paste to be applied in a plurality of cementing operations. The cement paste can be used to effectively improve the cementing job quality and raise the service life of the cement stone, and has an extensive application prospect.

The invention discloses a meteorologic balloon and a production method thereof. The raw materials consist of a solid raw material, an oily raw material and a gluey raw material; the solid raw material comprises the following components by weight: 0 to 0.30 portion of potassium hydroxide, 0 to 0.15 portion of casein, 0 to 0.10 portion of peregal O, 1.00 to 3 portions of sulfur, 1.00 to 2 portions of N-phenyl-2-naphthylamine, 1.00 to 2 portions of N-phenyl-N'-isopropyl-ursol, 1.50 to 3 portions of ethyl-phenyl-zinc dithiocarbamate, 0.20 to 5 portions of zinc oxide, and 5 to 30 portions of chloroprene polymer; the oily raw material is dioctyl sebacate, and the weight rate of the dioctyl sebacate is 5.00 to 10.0 portions; and the gluey raw material is centrifugally-concentrated natural latex, and the adding amount of the centrifugal concentrated natural latex is 100 portions. The weight of the meteorologic balloon is 1,600 to 1,700 grams, the length of the balloon body is 3.05 to 3.55 meters, the width of the ball handle is 10 to 11 centimeters, and the length of the ball handle is 12 to 16 centimeters. The meteorologic balloon can adapt to the requirement of probing high-altitude meteorological elements of more than 35,000 meters, has the advantages of good aging resistance, high blastoff height, long balloon service time and the like, and can effectively overcome the morning-evening difference.

The invention provides a double-layer sandwich or multi-layer sandwich multi-latex condom and a preparation method thereof. The preparation method of the condom comprises the following steps: vulcanizing natural latex; emulsifying and dispersing polymer materials such as polyurethane or polyisoprene or butyronitrile or other non-natural latex and making the polymer materials into synthetic latex; and dipping a condom die in the natural latex and the synthetic latex respectively and then drying to finally obtain the double-layer sandwich or multi-layer sandwich multi-latex condom the middle layer of which is made from the natural latex or the synthetic latex, wherein, the innermost layer and the outermost layer of the condom can be made from the same material or different materials. The double-layer sandwich or multi-layer sandwich multi-latex condom of the invention has stretch rate and comfortability of the natural latex as well as high compactness of the synthetic latex, thus being applicable to obstructing penetration of small molecules such as hepatitis, AIDS virus and the like.

The invention relates to an environmental-friendly ventilation type composite natural emulsion product as well as a preparation method and application thereof, and belongs to the technical field of emulsion products. The environmental-friendly ventilation type composite natural emulsion product is prepared from the following raw materials in parts by weight: 190-210 parts of natural emulsion, 20-24 parts of sulphur, 11-13 parts of an oxidizer, 1-1.7 parts of a dispersing agent, 95-105 parts of an accelerant, 36-39 parts of a hardener, 2-3 parts of castor oil, 5-7 parts of oleic acid, 1.6-2.4 parts of potassium hydroxide, 14-16 parts of styrene-butadiene co-polymerized rubber emulsion and 130-142 parts of water. The environmental-friendly ventilation type composite natural emulsion product disclosed by the invention not only has favorable ventilation perspiration properties and favorable bacterial inhibition, but also has excellent toughness, excellent wear resistance and favorable density and hardness, so that emulsion products are soft and comfortable, are favorable in hand feel, can effectively protect skins and are environmental-friendly and healthy.

The present invention refers to a topical formulation containing natural latex or fraction thereof, for topical application, aiming to provide skin regeneration. It particularly refers to a formulation comprising latex from plants of the families Euphorbiaceae, such as Hevea brasiliensis, Apocinaceae, such as guava and sorb, Compositae such as guayule, Caricaceae such as papaya, or one of its fractions, whose topical application provides the skin with regeneration benefits, such as whitening or elimination of senile spots, increase in turgor, improved texture, shine and resilience

A rubber latex composition is disclosed having reduced allergenicity. Methods for producing a rubber latex composition having reduced allergenicity are also disclosed.

The present invention discloses a phenolic aldehyde-rubber copolymer emulsion and its preparation method. Said emulsion is made up by using resorcinol formaldehyde (RF) resin and one or several kinds of butadiene-vinylpyridine latex and/or neoprene latex, carboxy styrene-butadiene latex, acrylate latex, natural rubber latex, chlorosulfonated polyethylene latex and hydrobutadiene-acrylonitrile latex, making them undergo the process of copolymerization and adding formaldehyde. Said invention also provides the concrete steps of its preparation method.