Disclosed is a method for producing a surface-treated carbon black, including a step (step (i)) of mixing a carbon-black-containing aqueous-slurry-solution in which a carbon black is dispersed in water with a dihydrazide compound, and subsequently removing the water. Disclosed is a method for producing a rubber wet masterbatch, including: a step (I) of mixing a carbon-black-containing aqueous-slurry-solution in which a carbon black is dispersed in water, a rubber latex solution, and a dihydrazide compound with each other to produce a carbon-black-containing aqueous-rubber-latex-solution; a step (II) of solidifying the resultant carbon-black-containing aqueous-rubber-latex-solution to produce a carbon-black-containing rubber solidified product; and a step (III) of dehydrating and drying the resultant carbon-black-containing rubber solidified product to produce the rubber wet masterbatch. These producing methods can give a vulcanized rubber low in exothermicity, and a rubber composition restrained from being lowered in scorch property (or having scorch resistance).

As a rubber composition excellent in fatigue resistance and a method for producing the same, this disclosure provides a rubber composition containing a zinc oxide, wherein: a total volume of aggregates of the zinc oxide with a diameter of 20 μm or more is 0.008 or less in the rubber composition by volume fraction; and a method for producing the rubber composition, comprising: preparing a wet masterbatch by using a carbon black with a surface average acidic functional group amount (μeq/m.sup.2) of 0.15 or more and less than 3.00, preferably 0.40 or more and less than 1.50; and compounding a zinc oxide with the wet masterbatch.

Methods to make a silica and carbon black elastomer composite with a destabilized dispersion that includes silica are described, along with particle reinforced elastomer composites made from the methods. The advantages achieved with the methods are further described.

Methods to make a silica elastomer composite with a destabilized dispersion of silica are described, along with silica elastomer composites made from the methods. The advantages achieved with the methods are further described.

A method for producing a rubber composition containing a rubber wet master batch has a masticating process. The masticating process comprises step 1 of charging the rubber wet master batch into an enclosed kneading chamber that has a stirring rotor showing a rotation speed controllable automatically through a control unit and that is capable of detecting and outputting an internal temperature, step 2 of setting a first control time and a first target temperature in the control unit, and step 3 of stirring the inside of the kneading chamber while making a PID control for adjusting an actually measured temperature in the kneading chamber to the first target temperature through the control unit on the basis of information on the actually measured temperature and the first target temperature, thereby automatically controlling the rotation speed, until the first control time elapses after the completion of the two steps.

An elastomeric article having a rubber component comprising polyisoprene and an aldehyde aniline condensate, the elastomeric article having less than 1 ppm diisopropyl xanthogen polysulfide residue.

A latex or natural rubber composition or formulation, latex or rubber products made using the same, and methods of preparing a vulcanized rubber and latex or natural rubber products are disclosed. The composition/formulation includes latex or natural rubber, 0.1-5 phr of a vulcanization activator, and 0.5-10 phr of one or more accelerators and/or additional activators. At least one accelerator and/or additional activator is a nanocomposite zinc oxide. The method includes. mixing a source of the latex or rubber with a vulcanization activator and one or more nanocomposite zinc oxides in a tank or vessel to form a latex or rubber formulation, dipping or at least partially immersing one or more molds or formers in the latex or rubber formulation to form a latex or rubber coating thereon, and curing the latex or rubber coating to vulcanize the latex or rubber coating. The vulcanized latex product is strong and has antimicrobial properties.

A masterbatch manufacturing method in accordance with the present disclosure comprises an operation in which pre-coagulation rubber latex comprising filler is coagulated to obtain a coagulum; an operation in which the coagulum is dewatered; and an operation in which the dewatered coagulum is plasticized as it is dried by means of an extruder; wherein, during the operation in which the dewatered coagulum is plasticized as it is dried, the coagulum comprises a peptizing agent.

A masterbatch manufacturing method comprising: an operation in which a natural rubber latex, and a rubber latex having a mass-average molecular weight that is less than a mass-average molecular weight of the natural rubber latex, are mixed to obtain a pre-slurry-mixing rubber latex for which a mass-average-molecular-weight-to-number-average-molecular-weight ratio is 6 to 10; an operation in which the pre-slurry-mixing rubber latex and a filler slurry are mixed to obtain a pre-coagulation liquid mixture; and an operation in which the pre-coagulation liquid mixture is coagulated.

A silica elastomer composite having superior mechanical properties.