A rubber composition based on at least one diene elastomer, a reinforcing filler predominantly comprising a filler covered at least partially by silica and a crosslinking system. The dispersion of the filler in the elastomeric matrix has a Z score greater than or equal to 70, and the composition is devoid of agent for coupling the filler with the elastomer.

In various embodiments, methods for producing aqueous polyisoprene latex from natural cis-1,4-polyisoprene are described. The natural cis-1,4-polyisoprene may be sourced from guayule scrubs. In various embodiments, the method comprises extracting guayule plant material to form a miscella, fractionating the miscella to a preliminary cement, diluting the preliminary cement to a cement for dispersing, dispersing the cement in an aqueous surfactant mixture under high shear to produce an emulsion, and de-solventizing the emulsion to produce an aqueous latex dispersion. The rubber solids level can then be adjusted by centrifugation and dilution in water to produce a final aqueous cis-1,4-polyisoprene latex.

A method for producing a rubber wet masterbatch includes mixing a rubber latex solution and a coagulant with a carbon black-containing slurry aqueous solution in which a carbon black is dispersed in water, to produce a carbon black-containing rubber latex aqueous solution having a pH of 7 to 8.5; adding additional coagulant to the carbon black-containing rubber latex aqueous solution obtained to produce a carbon black-containing rubber coagulum; and dehydrating and drying the carbon black-containing rubber coagulum obtained to produce a rubber wet masterbatch, wherein a rubber component contained in the rubber latex solution is added at an addition rate of 10 g/min or more and 100 g/min or less and the part of the coagulant is added at an addition rate of 10 mmol/min or more and 100 mmol/min or less per 100 g of the carbon black contained in the carbon black-containing slurry aqueous solution.

An object of the prevent invention is to provide a rubber latex compound that enables manufacturing a glove which is superior in terms of touch panel responsiveness, and has superior flexibility. The rubber latex compound according to one aspect of the present invention is a rubber latex compound for a glove containing a rubber latex as a principal component, wherein carbon black, an anionic surfactant, a nonionic dispersant, and a water-soluble polymer are contained in the rubber latex compound; a DBP oil absorption of the carbon black is no less than 250 ml/100 g and no greater than 600 ml/100 g, and a volatile content of the carbon black is no less than 0.3% by mass and less than 1.0% by mass; an amount of addition of the water-soluble polymer with respect to 100 parts by mass of the carbon black is no less than 8 parts by mass and no greater than 50 parts by mass; and a total amount of addition of the nonionic dispersant and the water-soluble polymer with respect to 100 parts by mass of the carbon black is no less than 38 parts by mass and no greater than 200 parts by mass.

The present invention provides nanocellulose/surfactant composites having excellent redispersibility in water and related compositions and methods, including methods for producing the composites. Included is a nanocellulose/surfactant composite containing a nanocellulose and a surfactant, the nanocellulose/surfactant composite having a moisture content of lower than 10%, the surfactant including an ionic surfactant having a weight average molecular weight of 3000 or more.

A method for producing a rubber wet masterbatch, the method including: adding a rubber latex solution to a carbon black-containing slurry aqueous solution in which a carbon black is dispersed in water and mixing the solutions to produce a carbon black-containing rubber latex aqueous solution; coagulating the carbon black-containing rubber latex aqueous solution obtained to produce a carbon black-containing rubber coagulum; cleaning the carbon black-containing rubber coagulum obtained to produce a cleaned carbon black-containing rubber coagulum; and dehydrating and drying the cleaned carbon black-containing rubber coagulum obtained to produce a rubber wet masterbatch, wherein an amount of an acetone extract from the cleaned carbon black-containing rubber coagulum is 2% by mass or less after drying the coagulum at 23° C. for 24 hours and further at 90° C. for 2 hours. Vulcanized rubber having excellent low exothermicity and excellent abrasion resistance can be obtained by the method.

A latex composition includes a sulfur-based vulcanizing agent and a xanthogen compound mixed with a conjugated diene polymer latex, the aqueous dispersion of a sulfur-based vulcanizing agent being a dispersion in which the sulfur-based vulcanizing agent is dispersed in water using an anionic surfactant.

Disclosed herein are polysaccharide-elastomer masterbatch compositions and processes for preparing the masterbatch compositions. One method comprises a step of a) mixing i) an aqueous polysaccharide dispersion, or ii) a basic aqueous polysaccharide solution, with a rubber latex solution containing a rubber component to form a mixture. The method further comprises the steps of: b) coagulating the mixture obtained in step a) to produce a coagulated mass; and c) drying the coagulated mass obtained in step b). The masterbatch compositions are useful in preparing rubber-containing articles.

A method for manufacturing micronized rubber powders including grinding of a rubber granulated feedstock, size classification and storage of the micronized rubber powders thus obtained. A rubber formulation including at least one natural or synthetic rubber, a micronized rubber composition and optionally one or more of processing aids, antidegradants, fillers, accelerators and curatives. A method for manufacturing a rubber product, as well as to a solid rubber product.

A masterbatch manufacturing method comprises: an operation in which carbon black is dispersed in dispersion medium in presence of a surface active agent having an aromatic ring to prepare a carbon black slurry; an operation in which at least the carbon black slurry and a rubber latex are mixed to prepare a liquid mixture; and an operation in which the liquid mixture is coagulated.