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.

The present invention provides a method for producing a rubber composition containing a rubber component (A) which contains a copolymer of a conjugated diene compound and an aromatic vinyl compound, in which the conjugated diene compound amount in the copolymer is 50% by mass or more and 73% by mass or less and the molecular weight at the peak top of the molecular weight distribution of the polystyrene-equivalent number-average molecular weight of the copolymer as measured through gel permeation chromatography is 100,000 or more and 600,000 or less, a filler containing an inorganic filler (B), a silane coupling agent (C) and at least one accelerator (D) selected from guanidines, sulfenamides, thiazoles, thiurams, thioureas, dithiocarbamates and xanthates, wherein the rubber composition is kneaded in plural stages, and in the first stage (X) of kneading, the rubber component (A), all or a part of the inorganic filler (B), all or a part of the silane coupling agent (C) and the accelerator (D) are added and kneaded. The production method can produce a rubber composition excellent in low-heat-generation property and abrasion resistance.

A method of mixing a rubber composition includes a carbon introduction step and a uniform dispersion step. In the carbon introduction step, on the basis of a deviation between a rate of temperature increase of the rubber mixture (R) and a target value, at least one of a ram pressure (Pr) and a rotational speed (N) of the mixing rotor (2) is PID controlled so that the ultimate temperature of the rubber mixture (R) at the conclusion of the step is within a tolerance range. In the uniform dispersion step, the ram pressure (Pr) or the rotational speed (N) of the mixing rotor (2) is adjusted to reduce a deviation between a value based on successively detected data associated with a predetermined control target and a target value.

A kneader internal inspection device according to the present invention suspends and supports a photographing unit, which is arranged in an interior of a kneader and which photographs the interior, so as to be vertically movable in the interior of the kneader. Therefore, such a kneader internal inspection device is capable of easily inspecting the interior of the kneader.

A silica-containing rubber mixture includes at least one rubber, a sulphur-containing alkoxysilane, a crosslinking agent, a filler, and optionally further rubber auxiliaries, and the mixture also includes from 0.1 to 15 parts by weight, based on 100 parts by weight of rubber used, of a silicon-free polysulphide additive of the formula (I)
A-S—(S).sub.x—S—Y—S—(S).sub.x—S-A  (I)
where x is 0, 1 or 2, Y is an optionally substituted or heteroatom-containing aliphatic, cycloaliphatic or aromatic group, and A may include hydroxy, carboxy, or carboxyphenyl groups.

A fiber-reinforced polyimide resin molded article and a production process therefor. After a prepolymer of an addition reaction type polyimide resin and functional fibers are dispersed and kneaded together, the kneaded product is kept at a temperature not lower than the heat curing start temperature of the reaction type polyimide resin for a fixed amount of time or mixed with a thickener to increase its viscosity, and shaped at a temperature not lower than the heat curing start temperature of the reaction type polyimide resin to obtain a molded article having excellent sliding performance with a limit PV value of not less than 3,000 kPa.Math.m/s and excellent shape stability during molding and containing the functional fibers dispersed in the polyimide resin.

A rubber composition manufacturing method in accordance with the present invention comprises an operation in which at least rubber, silica, and silane coupling agent are kneaded in an internal kneader while kneading temperature is controlled so as to suppress occurrence of a coupling reaction between the silica and the silane coupling agent, wherein for at least a portion of time during which the operation is being carried out, at least the rubber, the silica, and the silane coupling agent are kneaded while a ram of the internal kneader is in a nonpressing state.

A rubber composition manufacturing method comprising an operation in which an intermeshing internal kneader is used to knead at least rubber, silica, and silane coupling agent, wherein the operation comprises a first step in which kneading which is accompanied by increase in kneading temperature is carried out during an initial phase of the operation; kneading is carried out during the first step while a ram is maintained in a state in which it is at a first position which is higher than a lowermost position within a range of movement of which the ram is capable; and during the first step, an effective volume when the ram is at the first position is 105% to 120% relative to a value of 100% for an effective volume when the ram is at the lowermost position.

One aspect of the present invention is a method for producing an ethylene vinyl acetate hot-melt adhesive, comprising: introducing a liquid including at least one of water and alcohol into a heating kneader while or after kneading a hot-melt adhesive material in a liquid state, at an amount of 0.05 parts by mass or more with respect to 100 parts by mass of the hot-melt adhesive material; and performing vacuuming while heating stirring or dispersing the hot-melt adhesive material and the liquid so as to come into contact with each other.

Modified silicas, having the following physicochemical parameters: a CTAB.sub.mod of <200 m.sup.2/g, a BET.sub.MP of 50-500 m.sup.2/g, a CTAB.sub.mod-BET.sub.MP of <0 m.sup.2/g, a carbon content of >0.5% by weight, a mode.sub.mod from CPS particle size determination of >50 nm, a d75.sub.mod from CPS particle size determination of 20-150 nm, a R.sub.min from Hg pore size determination, pressurized of <10 nm, and a sulfur content of ≤1.50% by weight.