To provide methods for producing a natural rubber which enable the production of a natural rubber with an increased molecular weight, and transgenic plants which are able to produce a natural rubber with an increased molecular weight. Included is a method for producing a natural rubber, the method including the steps of: introducing a gene coding for a cis-prenyltransferase (CPT) family protein derived from a rubber-producing plant A into a rubber-producing plant B to prepare a transgenic plant C; and producing a natural rubber using the transgenic plant C, the rubber-producing plant A producing a natural rubber having a higher molecular weight than a natural rubber produced by the rubber-producing plant B not transfected with the gene.

A process for producing tyres with auxiliary components for vehicle wheels is described. The process includes i) covering the external surface of an expandable chamber for tyre vulcanisation and moulding apparatuses with a first substantially cross-linkable polysiloxane composition and ii) covering the radially inner surface of the impermeable elastomeric material layer of the green tyre with a second substantially non-cross-linkable polysiloxane composition. An expandable chamber for tyre vulcanisation and moulding apparatuses and, a process for treating the expandable chamber are also described.

A mold for molding a tire tread comprises a plurality of mold segments. Each of the plurality of mold segments includes an integer number of tread pitch repetitions. The plurality of mold segments are structured to be coupled to each other end-to-end so as to form the mold such that the mold includes an integer number of tread pitches. The mold also includes at least one mold end segment positioned on at least one end of the mold and has a mold end segment length shorter than a length of each of the plurality of mold segments.

An object of the present invention is to provide a tire vulcanization method in which there is no air remained between a vulcanization mold and an unvulcanized tire in tire vulcanization, the unvulcanized tire easily fits the vulcanization mold and an occurrence of bareness is prevented. The present invention relates to a tire vulcanization process comprising an application process of applying a coating agent comprising powder on a surface of an unvulcanized tire and a vulcanization process of vulcanizing the unvulcanized tire obtained in the application process, a tire production method comprising the vulcanization method, and a tire produced by the tire production method.

A pneumatic tire is vulcanized using a bladder provided with a coating layer formed of a release agent, and includes a sealant layer disposed on an inner surface of a tread portion in a tire circumferential direction. The amount of silicon of the release agents detected in at least a placement region of the sealant layer by fluorescence X-ray analysis is from 0.1 wt. % to 10.0 wt. %.

A pneumatic tire is vulcanized using a bladder provided with a coating layer formed of a release agent, and includes a sealant layer disposed on an inner surface of a tread portion in a tire circumferential direction, the release agent having a thickness of from 0.1 m to 100 m in at least a placement region of the sealant layer, detected using an electron microscope.

A method of manufacturing a pneumatic tire including forming a green case by cylindrically winding a tire component member which includes at least one layer of a carcass ply. The green tire is shaped by expanding the green case into a toroidal shape with the supply of a fluid into the green case so that the green case adheres to a tread ring arranged radially outside the green case. The green tire is subjected to vulcanization molding within a mold die. During the shaping of the green tire, the fluid is supplied in accordance with a pressure profile which changes in a stepwise manner. The pressure profile is set such that a former stage pressure which allows the green case to expand to 35% to 40% of a full expansion amount is set lower than a final stage pressure in a final stage.

A method of manufacturing a pneumatic tire includes forming a green tire. Forming the green tire includes: a first step of forming a first belt portion by winding a first belt on an outer peripheral surface of an inner liner and, thereafter, forming a second belt portion by winding a second belt on the first belt portion thus acquiring a belt layer; and a second step of acquiring a reinforcing layer by winding a reinforcing belt on the second belt portion. The second step includes: a first parallel winding treatment where the reinforcing belt is wound one turn on a first circumference; a spiral winding treatment where the reinforcing belt is spirally wound in a tire width direction; and a second parallel winding treatment where the reinforcing belt is wound on a second circumference within a range of from 24030 with one turn set to 360.

A process for producing tyres including building a green tyre having two bead structures. Each bead structure includes a bead filler. The bead filler or another rigid component of the green tyre includes a final elastomeric compound produced by the following: feeding elastomeric polymer and reinforcement filler to a first batch mixing device; mixing and dispersing the reinforcement filler in the elastomeric polymer and unloading the obtained elastomeric compound; feeding the obtained elastomeric compound, along with at least 5 phr of reinforcement resin, to a continuous mixing device of intermeshing and co-rotating twin-screw or multi-screw type or of planetary type; mixing the reinforcement resin in the elastomeric compound and unloading the obtained elastomeric compound; and feeding the obtained elastomeric compound along with the components capable of facilitating the cross-linking to a second batch mixing device and mixing to obtain the final elastomeric compound. The first and second batch mixing device have two counterrotating rotors.

A curing press for tires that comprises: an upper cavity part having a vertically separable upper housing (9) and a top mold (11); a base having a lower cavity part that forms an arrangement to provide mold height adjustment during curing. The base comprises a bottom bolster structure (20) and a bottom mold (22). The bottom bolster structure comprising: ring means rotatably arranged with said bottom bolster structure, to facilitate closing or opening of said top mold and said bottom mold; the bolster structure comprises squeeze cylinders (24) having means to provide mold height adjustment. A squeeze retract stop assembly is provided to restrict vertically downward movement of said bottom mold during a tire curing process. The press comprises at least one locking lever (34) and at least one indexing lock pin (35) that is adapted to connect said lever (34) to lock holes (20a) in said bottom bolster structure (20) wherein each lock hole corresponds to a particular mold height.