Provided is a cross-linked rubber that can improve long-term sealing properties of a seal member in high-temperature and high-pressure environments. The cross-linked rubber is obtained through cross-linking of a cross-linkable rubber composition containing a fluororubber, carbon black, one or more carbon nanotubes, and an organic peroxide cross-linker, and has a 50% modulus of 5 MPa or more, a compression set (230 C., 500 hours) of 80% or less, and a rate of change of elongation at break between before and after a heat aging test (230 C., 72 hours) of not less than 10% and not more than 10%.

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.

Provided is a kneading device 1 for dispersing a dispersoid in a dispersion medium. The kneading device includes a casing in which a kneading material containing the dispersion medium and the dispersoid is accommodated, a rotor disposed in the casing and kneading the kneading material while dispersing the dispersoid in the dispersion medium by rotating about a rotation axis, and a detection unit detecting a dispersion degree of the dispersoid into the dispersion medium by observing a state of the kneading material in the casing.

A process for producing a wet rubber masterbatch yielded by using, as raw materials, at least a filler, a dispersing solvent, and a rubber latex solution, comprises a step (i) of mixing the filler, the dispersing solvent and the rubber latex solution with each other to produce a filler-containing rubber latex solution, a step (ii) of solidifying the filler-containing rubber latex solution to produce a filler-containing rubber solidified product, and a step (iii) of dehydrating the filler-containing rubber solidified product to produce the wet rubber masterbatch. At the time of representing the temperature of the filler-containing rubber solidified product before the dehydration in the step (iii) by T1 ( C.), and representing the temperature of the filler-containing rubber solidified product after the dehydration by T2 ( C.), the following expressions (1) and (2) are satisfied:
T1100(1)
80T2T1160(2).

A method for drying polyolefin-containing particles includes a drying step of supplying polyolefin-containing particles to a drying container, supplying a drying gas to the drying container, and drying the polyolefin-containing particles in the drying container. In the drying step, a numerical value determined by the following formula (a) is 441 or more and 600 or less.
38.0?[?]CXIS[dL/g]?0.500?CXIS content[% by mass]+1.20?particle temperature during drying[K]+3.29?drying time[hr]Formula (a):

It is described an apparatus for the extrusion and mixing of plastic materials, for example rubber-based and silicone-based materials, comprising a dump extruder body whereon two conical screws (2) converging towards an extrusion die (3) suitable for being occluded by closing means (4) are mounted, the conical screws (2) being accommodated within a low-pressure compounding chamber (1) and within a pair of converging conical channels also defining a high-pressure chamber (2), said low-pressure chamber (1) corresponding to an upstream area with respect to an extrusion direction, wherein said high-pressure chamber (2) and/or said low-pressure chamber (1) accommodate a presser body (5, 5, 6), defining a movable wall suitable for causing a controlled change in the volume of the respective chamber (1, 2).

The present invention discloses a rubber composition, a processing method thereof, and rubber product reinforced with silica using the same. The rubber composition comprises a rubber matrix and essential components, wherein, based on 100 parts by weight of the rubber matrix, the rubber matrix comprises, a branched polyethylene with a content represented as A, in which 0<A100, and an EPM and an EPDM with a total content represented as B, in which 0B<100; and the essential components comprise 1-10 parts of a crosslinking agent and 15-80 parts of silica. The rubber composition can be used for producing high-voltage insulating sheath rubber, high-temperature resistant conveyor belt, waterproof coil, rubber particles for plastic track surface layer, rubber plug, rubber roller, inner tube, tire tread, tire sidewall, and inner rubber layer of air-conditioner hose.

Provided are a polymer ready for introduction into a kneading machine which is milled with good milling efficiency in a kneading machine and which provides a kneaded mixture with excellent filler dispersion, and a rubber composition and a pneumatic tire containing the polymer. The present invention relates to a polymer ready for introduction into a kneading machine, excluding natural rubber, the polymer having a temperature within the range of 20 C. to 80 C. and satisfying the following formula (I):

(Tip clearance d of kneading machine).sup.3(Volume V of polymer ready for introduction into kneading machine)2.010.sup.4 cm.sup.3(I).

Provided are a method for producing pellets that are easy to be uniformly molded at the time of using the pellet for molding even when the pellets include a large amount of inorganic substance particles, the pellets, and a method for molding a resin molded article. The method for producing pellets according to the present invention includes a method for producing pellets formed from a resin composition including a crystalline macromolecule and an inorganic fine powder or organic fine powder in a mass ratio of 50:50 to 20:80, the method including the step of kneading the crystalline macromolecule and the inorganic fine powder or the organic fine powder so that the microcrystalline size of the crystalline macromolecule is 190 or smaller. The pellets according to the present invention are pellets formed from a resin composition including a crystalline macromolecule having a microcrystalline size of 190 or smaller, and inorganic substance particles in a mass ratio of 50:50 to 20:80.

A mixer (2) includes: a pair of rotors (44) arranged to have a gap (SP2) therebetween; a casing (45) in which a chamber (C2) in which the pair of rotors (44) is disposed, an introduction port (51) for introducing a material to be mixed (W) into the chamber (C2), and a discharge port (52) for discharging the material to be mixed (W) from the chamber (C2) are formed; a sensor (80) which is disposed above the pair of rotors (44) and detects variation in position or pressure of the material to be mixed (W); and a control unit (82) which controls rotation of the pair of rotors (44), based on a detection result of the sensor (80).