RU2389612C2 - Pneumatic tire - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Tread, breaker and side rubber features bulk resistivity of 1·10⁸ Ohm·cm or higher. Pneumatic tire comprises additionally conducting rubber fitted into tread so that its extends onto tread surface, side rubber fitted into rim side contact with tire side, and electrically conducting rubber to connect conducting rubber with side rubber. Conducting rubber, side rubber and electrically conducting rubber feature bulk resistivity of 1·10⁸ Ohm·cm or higher.

EFFECT: reduced resistance to swinging and discharge of static electricity originating in running.

14 cl, 4 dwg

Description

This application is based on Japanese Patent Applications No. 2007-159029, filed June 15, 2007, No. 2007-172695, filed June 29, 2007, No. 2007-188542 and 2007-188547, filed June 19, 2007 in Japan Patent Office, the entire contents of which are incorporated herein by reference.

The present invention relates to pneumatic tires with improved safety by maintaining low rolling resistance and reducing static electricity generated by movement.

In recent years, various methods have been proposed for using silicon dioxide in a tread, breaker, sidewall or other elements of a tire in order to reduce rolling resistance in a tire, as well as to maintain tire grip characteristics with a wet road surface. However, the problem of insufficient safety arises if silicon dioxide is contained in large quantities, since the electrical resistance of the tire increases, causing a spark due to static electricity, for example, during the supply of fuel for a car, so that the fuel ignites. Therefore, there is a need for a tire having reduced rolling resistance while maintaining the grip characteristics of the tire with a wet road surface and capable of preventing the generation of static electricity.

Japanese Patent Laid-Open No. 08-230407 describes a pneumatic tire with improved electrical conductivity capable of preventing a discharge phenomenon caused by the accumulation of static electricity on a car body in which the rubber tread mixture contains soot in an amount of 50 wt. hours or less per 100 wt. including a rubber component and a carbon-free enhancing agent; the rubber element of the sidewall contains soot in an amount of 40 wt. hours or less per 100 wt. including rubber component; and an electrically conductive thin film is placed on the tread and sidewall. The publication discloses that the rubber element forming the electrically conductive thin film contains carbon black in an amount of 60 wt. hours or more per 100 wt. parts of the rubber component and in an amount of 35 wt.% of the total rubber composition.

Japanese Patent Publication No. 2000-190709 proposes a pneumatic tire capable of maintaining excellent wet grip performance and effectively reducing tire electrical resistance, stably showing these characteristics from the start of operation to the wear limit. The publication proposes a pneumatic tire in which the tread rubber includes a main part of the tread rubber made of an insulating rubber material having a volume resistivity of 1 · 10 ⁸ Ohm · cm or more, and an external electrically conductive part made of an electrically conductive rubber material of the shoulder part having volume resistivity less than 1 x 10 ⁸ ohm · cm, the tire forming a contact area with the road, together with the main part of the tread, and the end portion extends in the tire axial direction utr from the edge of the contact area at a distance of from 3% to 35% of the contact area; the external electrically conductive part has the form of a sheet with a thickness of from 0.01 to 1.0 mm, extending to the outer surface of the tread, including the wall and the bottom of the transverse grooves extending in the longitudinal direction of the tire; wing rubber, sidewall rubber and clinch rubber are made of electrically conductive rubber material of the shoulder region; and the external electrically conductive part reaches the wing rubber.

Japanese Patent Publication No. 10-036559 proposes as a rubber composition for a tire sidewall capable of imparting low rolling resistance, wear resistance, excellent wet grip and low electrical resistance to a tire, a rubber composition that can be obtained by mixing and mixing 100 wt. .h. specific diene rubber; from 5 to 50 parts by weight carbon black having an oil adsorption value of DBP (dibutyl phthalate) of 120 ml / 100 g or less and a surface area of CTAB (cetyltrimethylammonium bromide absorption method) of 130 m ² / g or less; from 10 to 60 parts by weight precipitated silica having an oil adsorption value by DBP of 200 ml / 100 g or more and a specific surface area by BET of 180 m ² / g or less, and a silane coupling agent in an amount capable of keeping the reactivity coefficient within certain limits.

Japanese Patent Publication No. 8-034204 proposes a tire tread comprising a tape made from a rubber composition for a tire tread having a high resistivity due to the use of silicon dioxide as a reinforcing agent and a predetermined lateral width with respect to the length direction, and an electrically conductive tape extending in the length direction along this lateral width and made of a rubber composition for a tire having a volume resistivity of 10 ⁸ Ohm · cm or less and a low resistance.

However, from the point of view of the methods described in published Japanese patents No. 08-230407, 2000-190709, 10-036559 and 08-034204, there is a need to achieve a better ratio between low rolling resistance and high safety.

The present invention provides an effective prevention of accumulated static electricity arising in the contact area of the tire with the road or in the region in which the tire contacts the rim during driving while maintaining a low level of rolling resistance.

The present invention provides a pneumatic tire, including:

a tread, a sidewall, a side, a carcass extending from a tread to a side through a sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, where the tread rubber, the breaker rubber and the sidewall rubber, formed respectively on the tread, breaker and sidewall, have a volumetric resistivity of 1 · 10 ⁸ Ohm · cm or more; the pneumatic tire further includes conductive rubber embedded in the tread so that said conductive rubber at least partially extends to the tread surface; bead rubber located in the contact area of the bead of the rim with the bead of the tire; and conductive rubber electrically connecting conductive rubber to bead rubber, where conductive rubber, bead rubber and conductive rubber have a resistivity of less than 1 · 10 ⁸ Ohm · cm.

The bead rubber is a clinch rubber or a side tape rubber. The conductive rubber is preferably formed continuously in the longitudinal direction of the tire. In addition, the conductive rubber preferably has a thickness of 0.2 to 2 mm.

In accordance with another aspect of the present invention, there is provided a pneumatic tire including a tread, a sidewall, a bead, a carcass extending from a tread to a bead through a sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, where the tread rubber, the breaker rubber and the sidewall rubber formed respectively on the tread, breaker and sidewall, have a volume resistivity of 1 · 10 ⁸ Ohm · cm or more; the pneumatic tire further includes a conductive rubber of the shoulder region located in the lower part of both edges of the belt; coating rubber covering the upper part of the breaker and having an area of at least 5 mm for contact with the conductive rubber of the shoulder region; conductive rubber in contact with the coating rubber and embedded in the tread so that said conductive rubber at least partially extends to the tread surface; and bead rubber in contact with the lower end of the carcass and located in the contact area of the bead of the rim and bead of the tire, where the rubber of the layer forming the carcass, the conductive rubber of the shoulder region, the coating rubber, the conductive rubber and the bead rubber have a volume resistivity of less than 1 · 10 ⁸ Ohms ·cm.

At least one of the elements including the rubber of the layer forming the carcass, the conductive rubber of the shoulder region, the coating rubber, the conductive rubber and the bead rubber, preferably comprises a metal foil or electrically conductive carbon black.

The layer rubber, the conductive rubber of the shoulder region, the coating rubber, the conductive rubber and the bead rubber contain soot with a specific surface area measured from nitrogen adsorption of 100 m ² / g or more in an amount of 30 to 100 parts by weight. per 100 parts by weight rubber component.

Moreover, the layer rubber, the conductive rubber of the shoulder region, the coating rubber, the conductive rubber and the bead rubber contain metal foil in an amount of 1 to 10 parts by weight. per 100 parts by weight rubber component.

In accordance with another aspect of the present invention, there is provided a pneumatic tire including a tread, a sidewall, a bead, a carcass extending from a tread to a bead through a sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, in which the tread rubber, the belt rubber and sidewall rubber, formed respectively on the tread, breaker and sidewall, have a volume resistivity of 1 · 10 ⁸ Ohm · cm or more; the pneumatic tire further includes an electrically conductive rubber of the side portion extending from at least both edges of the belt to the board along the outside of the carcass; coating rubber having an area for contacting the side portion with the conductive rubber and arranged so that said coating rubber covers the upper portion of the breaker; conductive rubber in contact with the coating rubber and embedded in the tread so that the conductive rubber at least partially extends to the tread surface; and bead rubber in contact with the lower end of the side conductive rubber and located in the contact area of the bead rim and bead, where the side conductive rubber, coating rubber and conductive rubber contain soot with a specific surface area measured from nitrogen adsorption of 600 m ² / g or more, in an amount of 5 parts by weight or more per 100 parts by weight the rubber component and silicon dioxide with a specific surface area measured from nitrogen adsorption of 70 m ² / g or more and 250 m ² / g or less per 100 parts by weight the rubber component, and the conductive rubber of the side portion, the coating rubber and the conductive rubber have a volume resistivity of less than 1 × 10 ⁸ Ω · cm.

As soot, you can use Ketjen Black soot. The bead rubber preferably has a volume resistivity of less than 1 · 10 ⁸ Ω · cm. The thickness of the conductive rubber of the side portion is preferably set in the range of 0.2 to 2 mm.

In accordance with another aspect of the present invention, there is provided a pneumatic tire comprising a tread, a sidewall, a bead, a carcass extending from a tread to a bead through a sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, where the tread rubber, the breaker rubber and the rubber sidewalls formed respectively on the tread, breaker and sidewall have a volume resistivity of 1 · 10 ⁸ Ohm · cm or more; the pneumatic tire further includes a continuous portion of conductive rubber located between the carcass ply forming the carcass and the sidewall rubber and between the belt and the tread, having a thickness of from 0.2 to 3.0 mm; conductive rubber in contact with the conductive rubber of the continuous portion and embedded in the tread so that said conductive rubber at least partially extends to the tread surface; and bead rubber connected to the lower end of the continuous portion of the electrically conductive rubber and located in the contact area of the bead of the rim and the bead of the tire, where the conductive rubber of the continuous portion, the conductive rubber and the bead rubber have a volume resistivity of less than 1 × 10 ⁸ Ω · cm.

The electrically conductive rubber of the continuous portion preferably contains soot from wood resin in an amount of from 20 to 100 parts by weight per 100 parts by weight natural rubber component.

In the pneumatic tire of the present invention, it is possible to reduce the rolling resistance of the tire and effectively prevent the accumulation of static electricity occurring in the contact area or the area in which the tire contacts the rim during tire movement by using a rubber composition having low rolling resistance to form a tread, the breaker and the side, as well as by electrically connecting the bead rubber to the conductive rubber embedded in the tread so that said conductive rubber contacts ruet a road surface through a sidewall, and by placing a cover on top of the rubber belt when placing electroconductive rubber shoulder therebetween. Thus, it is possible to obtain a pneumatic tire that maintains a low specific fuel consumption characteristic and has improved safety during use.

In a pneumatic tire in accordance with another embodiment of the present invention, a rubber composition having a low rolling resistance is used for a tread, a breaker and a sidewall. On the other hand, the pneumatic tire has a structure in which the bead rubber is connected to the cover rubber located on the upper part of the belt, wherein the conductive side rubber is located between the bead rubber and the cover rubber, and the bead rubber is electrically connected to the conductive rubber embedded in the tread so that said conductive rubber is in contact with a road surface. Using this design, it is possible to reduce rolling resistance and effectively reduce the accumulation of static electricity that occurs in the contact area or the area in which the tire contacts the rim during movement. Therefore, it is possible to obtain a pneumatic tire while maintaining a low specific fuel consumption characteristic, with improved safety during use.

In the pneumatic tire of the present invention, it is possible to reduce the rolling resistance of the tire and effectively prevent the accumulation of static electricity occurring in the tire contact area or the area in which the tire contacts the rim during tire movement by using a material having high electrical resistance as rubber for forming tread, breaker and sidewalls, connecting a continuous section of electrically conductive rubber provided between the carcass layer and the sidewall rubber and between the breaker and the prote torus, with the conductive rubber, which provides conductive rubber contact with the road surface, and setting the electric resistance and the thickness of the conductive rubber portion continuous in predetermined ranges. Thus, it is possible to obtain a pneumatic tire while maintaining a low specific fuel consumption characteristic, with improved safety during use.

The above and other objectives, features, aspects and advantages of the present invention will become more apparent from the further detailed description of the present invention, accompanied by drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the right half section of a pneumatic tire in accordance with embodiment 1 of the present invention.

Figure 2 shows the right half section of a pneumatic tire in accordance with embodiment 2 of the present invention.

Figure 3 shows the right half section of a pneumatic tire in accordance with embodiment 3 of the present invention.

Figure 4 shows the right half section of a conventional pneumatic tire.

Basic design

The basic construction of the pneumatic tire of the present invention is described with reference to FIG. 1, showing the upper right half of the cross section of the tire.

The tire 1 is provided with a tread rubber 7 forming a tread, a sidewall rubber 8 forming a pair of sidewalls extending from both edges of the tread rubber 7 in a direction radially inward of the tire, and a pair of beads located on the inner end of each sidewall. On board, the rubber 3 of the crimp portion and the bead belt 2 are located in the area of contact with the bead of the rim. The carcass 10 connects a pair of sides, and the belt rubber 9, forming a belt, is located on the radially outer side of the carcass 10. The carcass 10 is formed of at least one carcass ply with the carcass cord located in a specific way, and the carcass ply is folded back from the inside to the outer the axial direction of the tire around the bead ring 13 and the bead filler 11, from the upper end of the bead ring 13 towards the sidewall through the tread and sidewall and is clamped by the clamping part.

The pneumatic tire of the present invention has a structure in which the conductive rubber 6 is disposed on the tread rubber 7 such that said conductive rubber partially extends into the contact area, and the conductive rubber 6 is electrically connected to the rubber 3 of the crimp portion and / or rubber 2 of the side side rubber tape. With this design, it is possible to discharge static electricity to the outside of the tire, even if static electricity occurs as the tire moves.

It is possible to form an electrically conductive rubber from a plurality of electrically conductive elements, in the form of a continuous connection from the conductive rubber to the bead rubber.

EMBODIMENT 1

One example of the construction of the pneumatic tire of the present invention is the structure shown in FIG. 1, which shows the upper right half of the cross section of the tire. The tire 1 is provided with a tread rubber 7 forming a tread, a sidewall rubber 8 forming a pair of sidewalls extending from both ends of the tread rubber 7 in a direction radially inward to the tire, a crimping rubber 3 forming a crimping portion located on the inner end of the sidewalls and an onboard rubber 2 the tape forming the bead tape located on the top of the rim. The carcass 10 is laid over the crimp part and between the rubber of the bead belt and the rubber 9 of the belt, forming a belt located on the radially outer part of the carcass 10. The carcass 10 is formed of at least one layer of the carcass with the carcass cord defined in a certain way, and the carcass layer is bent back from the inner part to the axially outer tire around the bead ring 13 and bead filler 11, passing from the upper end of the bead ring 13 towards the sidewall through the tread and sidewall, and is clamped by the clamping part. The breaker is formed of at least two breaker layers, which are breaker cords arranged in a certain way, and the breaker cords are stacked on top of each other, oriented alternately so that the breaker cords intersect each other. In the pneumatic tire of the present invention, the cover rubber 5 is located between the tread and the breaker. A conductive rubber 4 of the shoulder region having an area of at least 5 mm in contact with the cover rubber 5 is located between the carcass ply and both edges of the belt and the sidewall. The conductive rubber 6 is disposed on the tread rubber 7 so that it contacts the cover rubber 5 and partially extends into the contact area, and the conductive rubber 6 has a structure in which the cover rubber 5, the conductive rubber 4 of the shoulder region, the carcass 10 and the rubber 3 are electrically connected. crimp portion serving as side rubber and / or rubber 2 of the side tape.

Using the design described above, static electricity generated in the bead rubber located in the area in contact with the rim, or in the contact area during tire abrasion, is discharged to the outside of the tire through electrically connected electroconductive rubber elements inside the tire.

Tread rubber, breaker rubber and sidewall rubber

The volume resistivity of the tread rubber, the breaker rubber and the sidewall rubber forming the tire is set to 1 · 10 ⁸ Ohm · cm or more. Although carbon black was previously used as a reinforcing agent, it is possible to reduce rolling resistance by using silicon dioxide instead of carbon black. Moreover, since silicon dioxide is not a material derived from oil, silicon dioxide is more preferable from an environmental point of view compared to carbon black, which is a material obtained from oil. However, if silica is used, the volume resistivity may increase. In the present invention, the reduction in tire rolling resistance and basic characteristics, such as manufacturability (processability) of rubber, are retained when using silicon dioxide, and the problem of high electrical resistance with a volume resistivity of the rubber composition of 1 · 10 ⁸ Ω · cm or more is solved.

In the pneumatic tire of the present invention, 50 wt.% Or more of the aforementioned filler contained in the tread rubber, the breaker rubber and the sidewall rubber is preferably silicon dioxide. When 50 wt% or more of the filler is silica, the effect of reducing rolling resistance works well. The content of silica in the filler is preferably 70 wt.% Or more, more preferably 90 wt.% Or more. In the present invention, the entire filler may be silicon dioxide, but it is combined with other fillers in order to control the electrical conductivity and mechanical strength of the tread rubber, the rubber of the breaker and the rubber of the sidewall.

Silica may be 5 parts by weight. or more and 100 parts by weight or less per 100 parts by weight the rubber component in the tread rubber, the breaker rubber and the sidewall rubber. When the amount of silicon dioxide is 5 parts by weight or more per 100 parts by weight rubber component, it is possible to reduce the rolling resistance of the tire. When the amount of the mixture of silicon dioxide is 100 parts by weight or less, it is possible to favorably prevent a decrease in manufacturability due to an increase in the viscosity of the unvulcanized rubber composition and an excessive increase in cost.

As silica, conventionally used fillers can be used, examples of which include dry carbon black, wet black, colloidal silicon and the like. Among others, wet soot, mainly containing hydrated silicic acid, is preferred.

The specific surface area of silicon dioxide, measured from nitrogen adsorption (BET method), is preferably in the range from 100 to 300 m ² / g, more preferably from 150 to 250 m ² / g. When the specific surface area, measured from nitrogen adsorption, is 100 m ² / g or more, a sufficient reinforcing action is obtained to increase the tire wear resistance. On the other hand, when the specific surface area measured from nitrogen adsorption is 300 m ² / g or less, the processability of the rubber during manufacture will be good and good stability will be ensured during tire movement. The specific surface area is measured from nitrogen adsorption by the BET method in accordance with ASTM D3037-81.

Cover rubber

The coating rubber 5 of the present invention is positioned so that it is in contact with the conductive rubber 4 of the shoulder region and the conductive rubber 6 and is made of rubber having a volume resistivity of less than 1 × 10 ⁸ Ω · cm. It is possible to achieve the required degree of the effect of improving the electrical conductivity of the tire if the volume resistivity is less than 1 · 10 ⁸ Ohm · cm. Also, the volume resistivity can be set to the same as the resistance of the conductive rubber of the shoulder region, which is preferably 1 · 10 ⁷ Ω · cm or less, more preferably 1 · 10 ⁶ Ω · cm or less, and preferably 1 · 10 ³ Ohm · cm or more, more preferably 1 · 10 ⁴ Ohm · cm or more.

It is possible to achieve the desired degree of effect of improving the electrical conductivity of the tire if the thickness of the coating rubber 5 is 0.2 mm or more, and the rolling resistance of the tire does not deteriorate to a large extent if the thickness is 3.0 mm or less. The thickness of the conductive rubber of the shoulder region is preferably from 0.5 to 2.0 mm, particularly preferably from 0.9 to 1.5 mm. It is sufficient that the cover rubber 5 has an area in contact with the electrically conductive rubber of the shoulder region and the conductive rubber, and it is also possible to position the cover rubber 5 over the entire area between the tread and the breaker, or partially position it on the area where the conductive rubber is located, or to some extent beyond boundaries of the specified section.

The portion of the coating rubber in contact with the conductive rubber of the shoulder region and the conductive rubber is preferably a portion of the contact with the conductive rubber of the shoulder region made in the form of a tape extending in the longitudinal direction of the tire and having a width of 5 mm or more, more preferably 10 mm or more. Due to the contact of the conductive rubber of the shoulder region and the coating rubber under the conditions described above, it is possible to achieve a sufficient conductive effect. The contact area with the conductive rubber is preferably an area that matches the entire portion of the conductive rubber across the width of the tire.

In the present invention, the coating rubber may preferably contain carbon black in an amount of from 30 to 100 parts by weight. per 100 parts by weight rubber component. When the amount of carbon black is 30 parts by weight or more per 100 parts by weight rubber component, the conductivity of the coating rubber increases. When the amount of carbon black in the mixture is 100 parts by weight or less per 100 parts by weight rubber component, increased durability. The amount of carbon black in the mixture per 100 wt.h. the rubber component is preferably 35 parts by weight or more, more preferably 40 parts by weight or more, and preferably is 80 parts by weight or less, more preferably 70 parts by weight or less.

The specific surface area of the carbon black contained in the coating rubber, measured from nitrogen adsorption, is preferably 100 m ² / g or more and 1500 m ² / g or less. The mechanical strength of the coating rubber is good enough if the specific surface area, measured from nitrogen adsorption, is 100 m ² / g or more. A specific surface area measured from nitrogen adsorption of 1,500 m ² / g or less is preferable from the viewpoint of ensuring manufacturability during production. The specific surface area, measured from nitrogen adsorption, can preferably be 105 m ² / g or more, and preferably 1300 m ² / g or less, more preferably 1000 m ² / g or less. As a carbon black, carbon black from wood resin, which is not a raw material derived from oil, is suitable.

Silicon dioxide or a similar compound, for example, can be included as a filler in the coating rubber in addition to carbon black, but from the point of view of good electrical conductivity, carbon black can preferably be 8 wt.%, More preferably 15 wt.% Or more, even more preferably 100 wt.% or more, relative to the weight of the filler.

If the coating rubber contains silicon dioxide, the amount of silicon dioxide in the mixture is, for example, 10 parts by weight or more and 55 parts by weight or less per 100 parts by weight rubber component. It is possible to reduce the rolling resistance of a tire if the amount of silicon dioxide in the mixture is 10 parts by weight. or more per 100 parts by weight rubber component, and rolling resistance is deteriorated if the amount of silicon dioxide in the mixture exceeds 55 parts by weight

The specific surface area of silica, measured from nitrogen adsorption (BET method), is preferably in the range of 70 to 250 m ² / g, more preferably 80 to 240 m ² / g. When the specific surface area measured from nitrogen adsorption is 70 m ² / g or more, a sufficient reinforcing action is achieved, favorably improving the rolling resistance of the tire. When the specific surface area, measured from nitrogen adsorption, is less than 250 m ² / g, the processability of the rubber during manufacture will be good and good stability will be ensured during movement. The specific surface area of silica was measured from nitrogen adsorption by the BET method in accordance with ASTM D3037-81.

It is possible to adjust the volume resistivity of the coating rubber to a small value if it contains metal foil in an amount of 1 to 10 parts by weight, preferably 1 to 3 parts by weight. per 100 parts by weight rubber component. As a metal foil, a foil having a thickness of 10 to 50 μm, an inner diameter (D1) of 0.1 to 0.3 mm, an outer diameter (D2) of 0.2 to 0.5 mm, and a size ratio (D2 / D1) 2 to 5.

Conductive Shoulder Rubber

The electrically conductive rubber 4 of the shoulder region in the present invention is made of rubber having a volume resistivity of less than 1 · 10 ⁸ Ohm · cm, and is located between the layer of the carcass forming the carcass 10, described below, and the edge portion of the belt and the sidewall. It is possible to achieve the required degree of the effect of improving the electrical conductivity of the tire if the volume resistivity of the electrically conductive rubber 4 of the shoulder region is less than 1 · 10 ⁸ Ohm · cm. Also, the volume resistivity of the conductive rubber 4 of the shoulder region is preferably set to less than 1 · 10 ⁷ Ω · cm or less, more preferably 1 · 10 ⁶ Ω · cm or less. If you use a rubber mixture containing an electrically conductive component in large quantities, it is possible to reduce the electrical resistance, but at the same time, the rim is easily corroded due to the acceleration of the electrochemical reaction in the contact area of the tire and rim. To avoid corrosion, the volume resistivity of the conductive rubber of the shoulder region is preferably set to 1 · 10 ³ Ω · cm or more, more preferably 1 · 10 ⁴ Ohm · cm or more.

The electrically conductive rubber 4 of the shoulder region is continuously formed or in sections in the longitudinal direction between the carcass layer forming the carcass and the edge portion of the belt and the sidewall, as described above, and the thickness or shape of the rubber 4 is practically unlimited.

As the initial rubber mixture of the conductive rubber 4 of the shoulder region, a mixture can be used in which the rubber hardness and the like are adjusted in terms of imparting electrical conductivity by providing soot or metal foil in the same manner as in the coating rubber and reducing the separation rubber on both ends of the breaker.

Conductive rubber

In the present invention, the conductive rubber is embedded in the tread so that it partially extends into the contact area of the tire, and the other part is connected to the conductive rubber of the shoulder region so as to effectively discharge static electricity generated during the movement of the pneumatic tire through the contact area. Although the conductive rubber 6 shown in FIG. 1 is embedded in the central part of the tread 7, a plurality of sections of the conductive rubber are possible. The width W of the conductive rubber in the tire width direction may be from 0.2 to 10 mm, preferably from 0.9 to 1.5 mm. The conductivity effect will be small if the width is less than 0.2 mm, while the contact area of the conductive rubber in the tread relatively increases if the width exceeds 10 mm, worsening the contact characteristics. Although it is preferred that the conductive rubber be formed as a continuous layer in the longitudinal direction of the tire, the conductive rubber may be formed in portions in the longitudinal direction of the tire.

The volume resistivity of the conductive rubber is set smaller than the resistivity of the tread rubber, the rubber of the breaker and the rubber of the sidewall. The volume resistivity of the conductive rubber is less than 1 · 10 ⁸ Ohm · cm. If the volume resistivity of the conductive rubber is less than 1 · 10 ⁸ Ohm · cm, the bus conductivity is improved, which provides the effect of static electricity discharge. The volume resistivity of the conductive rubber is preferably 1 · 10 ⁷ Ω · cm or less, more preferably 1 · 10 ⁶ Ω · cm or less.

In the present invention, if the volume resistivity of the tread rubber, the breaker rubber and the sidewall rubber is set to 1 · 10 ⁸ Ohm · cm or more, since the volume resistivity of the conductive rubber of the shoulder region and the conductive rubber of the shoulder region attached to the conductive rubber of the shoulder region are set lower than the resistance of tread rubber, breaker rubber and sidewall rubber, while maintaining tire characteristics such as rolling resistance and durability, it is possible to effectively ryadit static electricity occurring in the pneumatic tire via the channel for electrically connecting a conductive rubber, electroconductive rubber shoulder, conductive rubber, etc.

It is possible to ensure the conductivity of the conductive rubber of the present invention by adding soot or metal foil to it in the same way as in the coating rubber, and also using a mixture designed to impart electrical conductivity based on a mixture of tread rubber, from the point of view of improving contact characteristics.

Frame

The carcass 10 in the present invention is formed of at least one layer of carcass cords arranged in a specific manner. The carcass ply has a structure in which carcass cords arranged parallel to each other are embedded in rubber. Examples of fibrous materials for forming carcass cords include viscose fiber, nylon, polyester fiber, aramid fiber, and the like, and can be used individually or in combination of two or more. Among the above materials, it is preferable to use viscose fiber, since viscose fiber is a natural raw material, and preferably a content of 90 wt.% Or more viscose fiber relative to the fibrous materials forming the carcass cord.

The volume resistivity of the rubber of the layer is set smaller in magnitude than the resistance of the tread rubber, the breaker rubber and the side rubber. The volume resistivity of the rubber of the layer is less than 1 · 10 ⁸ Ohm · cm. If the volume resistivity of the rubber of the layer is less than 1 · 10 ⁸ Ohm · cm, it is possible to provide the effect of discharging static electricity due to improved electrical conductivity of the tire. The volume resistivity of the rubber of the layer is preferably 1 · 10 ⁷ Ω · cm or less, more preferably 1 · 10 ⁶ Ω · cm or less.

In the present invention, if the volume resistivity of the tread rubber, the breaker rubber and the side rubber is set to 1 · 10 ⁸ Ohm · cm or more, since the volume resistivity of the layer rubber and the cover rubber, the conductive rubber of the shoulder region and the conductive rubber connected to the rubber of the layer, set lower than the resistance of the tread rubber, the breaker rubber and the sidewall rubber, while maintaining tire characteristics such as rolling resistance and durability, it is possible to further improve the electric roprovodnost tire when sharing shoulder area electroconductive rubber, conductive rubber, etc.

For the rubber of the layer of the present invention, a mixture essentially the same as for the coating rubber, but preferably containing soot or metal foil, can be used to provide electrical conductivity based on the traditional rubber mixture of the layer, from the point of view of maintaining adhesion to the cord layer.

Moreover, in the present invention, the layer is arranged so as to contact at least the rubber of the crimp portion or the rubber of the side tape. In addition to the structures of the continuous conductive rubber of the shoulder region, the cover rubber and the conductive rubber, the carcass ply layer having a low volume resistivity is arranged so as to contact the crimp rubber, the sideband rubber and the conductive rubber of the shoulder region, significantly improving the efficiency of discharging static electricity through rim.

Side rubber

As used herein, the term “bead rubber" means the rubber of the crimp portion or the rubber of the bead strip. Static electricity occurs in the drive unit during tire movement, and static electricity builds up in the car and also inside the tire through the rim and bead rubber. It is necessary to effectively discharge static electricity into the contact area (tires with the road) through the conductive rubber of the shoulder region. As shown in FIG. 1, it is necessary that the bead rubber, namely the crimp rubber or the sideband rubber, be electrically connected to the carcass 10. In FIG. 1, the crimp rubber is a rubber layer indicated by position number 3, the outer side of which in contact with the rim flange in the side of the tire, while the inner side is in contact with the bent end of the carcass 10.

In figure 1, the rubber of the bead tape is so located on the outer surface of the bead so as to contact the bead of the main part of the rim. As used herein, the term “sideband rubber 2” means rubber forming a sideband. That is, the rubber 2 of the side tape means the cover rubber of the cord if the side tape is a layer of cord layer, or means the rubber of the rubber side tape, if the side tape is a rubber side tape. The rubber 2 of the sideband shown in FIG. 1 includes the above values.

The present invention includes at least one of the constituent rubber of the crimp portion and the rubber of the bead strip as bead rubber. The volume resistivity of the bead rubber is less than 1 · 10 ⁸ Ohm · cm. Good electrical conductivity of the tire is achieved by maintaining the volume resistivity of the bead rubber less than 1 · 10 ⁸ Ohm · cm. The volume resistivity of the bead rubber is preferably less than 1 · 10 ⁷ Ohm · cm, more preferably 1 · 10 ⁶ Ohm · cm. Since it is required that the flange rubber, i.e. the crimp rubber and the flange rubber, have abrasion resistance, rigidity and hardness, it is possible to adjust the electrical resistance by adjusting the composition of the mixture to give it electrical conductivity by adding soot or metal foil in the same way as into the conductive rubber of the shoulder region or the conductive rubber.

Incarnation 2

One example of the construction of the pneumatic tire of the present invention is the structure shown in FIG. 2, which shows the upper right half of the cross section of the tire. The tire 1 is provided with a tread rubber 7 forming a tread, a sidewall rubber 8 forming a pair of sidewalls extending from both ends of the tread rubber 7 in a direction radially inward to the tire, a crimping rubber 3 forming a crimping portion located on the inner end of the sidewalls and an onboard rubber 2 the tape forming the bead tape located on the top of the rim. The frame 10 connects the sides at both ends, and the rubber of the breaker 9, forming a breaker, is located on the radially outer side of the frame 10.

The carcass 10 is formed of at least one carcass ply from a carcass cord arranged in a specific way, and the carcass ply is folded back from the inside to the axially outer tire around the bead ring 13 and bead filler 11, extending from the upper end of the bead ring 13 along towards the sidewall through the tread and sidewall, and clamped in the clamping zone. The belt 9 is formed of at least two belt layers, which are arranged in a certain way, the breaker cords, and the breaker cords are superimposed and oriented alternately so that the breaker cords intersect each other. In the pneumatic tire of the present invention, the cover rubber 5 is located between the tread and the breaker.

Embodiment 2 is characterized in that the side-conductive rubber 14 comprising a portion in contact with the cover rubber 5 is located adjacent to the frame 10 and extending from at least both ends of the belt to the contact point with the rubber 3 of the crimp portion. The conductive rubber 6 is disposed in the tread rubber 7 so as to contact the cover rubber 5 and partially extend into the contact area, and the conductive rubber 6 is electrically connected to the cover rubber 5, the conductive rubber 14 of the side portion and the rubber 3 of the crimp portion.

Using the above construction, it is possible to discharge static electricity generated in the bead rubber located in the area of contact with the rim or the area of contact during friction of the tire with the outside of the tire, through the elements of the conductive rubber.

Only the different elements of Embodiment 2 are described below, other elements are basically the same as in Embodiment 1.

Side Conductive Rubber

The electrically conductive rubber 14 of the side portion in the present invention abuts the outer side of the chassis 10 and approaches the board from both ends of the belt through the sidewall, so that the lower edge of the electrically conductive rubber 14 of the side portion is electrically connected to the rubber 3 of the crimp portion. The volume resistivity of the electrically conductive rubber of the side part is set to less than 1 · 10 ⁸ Ohm · cm. If the volume resistivity of the conductive rubber 14 of the side portion is less than 1 · 10 ⁸ Ohm · cm, it is possible to provide an effect of improving the conductivity of the tire. The volume resistivity of the rubber of the layer is preferably set to 1 · 10 ⁷ Ω · cm or less, more preferably 1 · 10 ⁶ Ω · cm or less. If a rubber mixture containing a large amount of an electrically conductive component is used, it is possible to reduce the electrical resistance, but at the same time, the rim is easily corroded due to the acceleration of the electrochemical reaction in the tire-rim contact area. To avoid corrosion, the volume resistivity of the conductive rubber of the shoulder region is preferably set to 1 · 10 ³ Ω · cm or more, more preferably 1 · 10 ⁴ Ohm · cm or more. The electrically conductive rubber of the side portion is adjacent to the outer side of the chassis, and a portion thereof may be located between the chassis and the belt and may be formed continuously or in portions in the tire longitudinal direction.

As the rubber composition of the conductive rubber 14 of the side part, the mixture can be used basically the same as for the cover rubber, and in order to reduce the separation of rubber at both edges of the belt, it is possible to use a composition in which the rubber hardness and the like are adjusted.

Frame

The carcass 10 in the present invention is formed of at least one layer of carcass cords arranged in a specific manner. The carcass ply has a structure in which carcass cords arranged parallel to each other are pressed into rubber. Examples of fibrous materials for forming carcass cords include viscose fiber, nylon, polyester fiber, aramid fiber, and the like, and can be used individually or in combination of two or more. Among the above materials, it is preferable to use viscose fiber, since viscose fiber is a natural raw material, and preferably 90 wt.% Or more viscose fiber is used relative to the fibrous materials forming the carcass cord.

Although the volume resistivity of the rubber of the layer is practically unlimited, the volume resistivity can be set in the same manner as in the tread rubber, the belt rubber and the side rubber. If the volume resistivity is less than 1 · 10 ⁸ Ohm · cm, it is possible to improve the electrical conductivity of the tire in order to provide the effect of discharging static electricity when combined with the adjacent side conductive rubber. In this case, the volume resistivity of the rubber of the layer can be set to 1 · 10 ⁷ Ohm · cm or less, more preferably 1 · 10 ⁶ Ohm · cm or less.

In the present invention, if the volume resistivity of the breaker rubber and the sidewall rubber is set to 1 · 10 ⁸ Ohm · cm or more, since the volume resistivity of the coating rubber, the side conductive rubber and the conductive rubber is set smaller than the resistance of the belt rubber and rubber sidewalls, while maintaining tire characteristics, such as rolling resistance and durability, it is possible to further improve the conductivity of the tire with the combined action of a coating rubber, conductive p rubber side, conductive rubber, etc. (static electricity generated in the pneumatic tire).

Moreover, the electrically conductive rubber of the side portion is arranged so as to also contact the bead rubber. Since the side rubber having a low volume resistivity, and the conductive rubber of the side, etc. in contact with each other, in addition to the structure in which the side conductive rubber, the cover rubber and the conductive rubber are continuous, it is possible to noticeably improve the efficiency of discharging static electricity through the rim.

Embodiment 3

Figure 3 presents the upper right half of the cross section of the tire in accordance with Embodiment 3 of the present invention. As shown in FIG. 3, the pneumatic tire T is provided with a tread 31, a breaker 32, a sidewall 33 and a bead 34 and comprises a seamless tape 38 located outside the breaker, a carcass 37 curved backward and clamped at both ends by a pair of bead rings 35, and a bead filler 36 extending from the upper part of the bead ring 35 towards the sidewall 33. In particular, a continuous portion of the electrically conductive rubber 39 extending over the entire surface is located between the carcass 37 and the sidewall rubber and between the belt 32 and the tread 31. The upper end of the continuous electric section the conductive rubber 39 is connected to the conductive rubber 311, which is embedded in the tread 31 and extends into the contact area (tires with the road), while the lower end of the continuous portion of the conductive rubber 39 is connected to the rubber 310 of the crimp formed on the side 34.

Using the above design, the static electricity accumulated inside the car and tire reaches the conductive rubber 311 through a continuous portion of the conductive rubber 39 to discharge through the contact area.

Continuous conductive rubber

In the present invention, a continuous portion of conductive rubber is located between the carcass 37 and the sidewall rubber and between the belt 32 and the tread 31. The upper end of the continuous portion of the conductive rubber is connected to the conductive rubber 311, which is embedded in the tread 31 and extends into the contact area (tires with the road), while the lower end of the continuous portion of the conductive rubber 39 is connected to the rubber 310 of the crimp portion formed on the side 34. Although the view in which the continuous portion of the conductive rubber 39 is located over the entire surface rotektora is shown in Figure 3, the continuous electroconductive rubber portion 39 may be disposed only at the edge of the tread and sufficient that this portion is connected with the conductive rubber 311, at least partially. Also, the lower end of the continuous portion of the electrically conductive rubber 39 is preferably connected to the rubber of the crimp portion.

In the present invention, it is possible to achieve the desired degree of the effect of increasing the conductivity of the tire if the thickness of the continuous portion of the conductive rubber 39 is 0.2 mm or more, while it is possible to prevent a significant deterioration in rolling resistance of the tire if the thickness of the continuous portion of the conductive rubber 39 is 3.0 mm or less. The thickness of the continuous portion of the electrically conductive rubber 39 is preferably from 0.5 to 2.0 mm, particularly preferably from 0.9 to 1.5 mm.

The volume resistivity of the electrically conductive rubber of the continuous portion formed in the pneumatic tire of the present invention is set to less than 1 × 10 ⁸ Ω · cm. If the volume resistivity of the conductive rubber of the continuous portion is less than 1 · 10 ⁸ Ohm · cm, the improvement of the conductivity of the tire is confirmed. The volume resistivity of the conductive rubber of the continuous portion is preferably less than 1 · 10 ⁷ Ohm · cm, more preferably less than 1 · 10 ⁶ Ohm · cm. Preferably, the volume resistivity of the conductive rubber of the continuous portion is as small as possible, in terms of the effect of increasing the electrical conductivity of the tire; however, to prevent the phenomenon that the rim is more susceptible to corrosion due to acceleration of the electrochemical reaction in the contact zone of the tire with the rim, if the electrical resistance is reduced by introducing a large amount of the electrically conductive component, the volume resistivity of the electrically conductive rubber of the solid portion is preferably set to 1 · 10 ³ Ohm · cm or more, more preferably less than 1 · 10 ⁴ Ohm · cm or more.

In the present invention, the conductive rubber of the continuous portion may preferably include carbon black in an amount of from 20 to 100 parts by weight. per 100 parts by weight rubber component. When soot is contained in an amount of 20 parts by weight or more per 100 parts by weight rubber component, the conductivity of the conductive rubber increases. Also, when the carbon black content is 100 parts by weight. or less per 100 parts by weight rubber component, durability is enhanced. If the amount of carbon black in the mixture is 100 parts by weight per 100 parts by weight the rubber component, its amount calculated on the total weight of the mixture is preferably 35 parts by weight or more, more preferably 40 parts by weight or more, and preferably is 80 parts by weight or less, more preferably 70 parts by weight or less.

The specific surface area of the carbon black contained in the conductive rubber of the continuous portion, measured from nitrogen adsorption, is preferably 100 m ² / g or more and 1500 m ² / g or less. The mechanical strength of the coating rubber will be good if the specific surface area of carbon black, measured from nitrogen adsorption, is 100 m ² / g or more, and the specific surface area of carbon black, 1500 m ² / g or less, measured from nitrogen adsorption, is preferable from the point of view of ensuring manufacturability during production. The specific surface area of carbon black, measured from nitrogen adsorption, can more preferably be 105 m ² / g or more, and preferably 1300 m ² / g or less, more preferably 1000 m ² / g or less. As the carbon black, carbon black is preferably used, which is not a crude oil derived material.

Silicon dioxide or a similar compound, for example, can be incorporated into the coating rubber as a filler in addition to soot, but, from the point of view of ensuring good electrical conductivity, carbon black can preferably be 8 wt.%, More preferably 15 wt.% Or more, even more preferably 100 wt.% or more of the total mass of fillers.

In the present invention, since the volume resistivity of the tread rubber, the breaker rubber and the sidewall rubber is set to 1 · 10 ⁸ Ohm · cm or more, and since the volume resistivity of the conductive rubber of the solid portion and the conductive rubber of the solid portion connected to the conductive rubber of the solid portion, set smaller than the resistance of the tread rubber, the rubber of the breaker and the rubber of the sidewall, while maintaining tire characteristics such as rolling resistance and durability, It is possible to efficiently discharge the static electricity generated in the pneumatic tire through the conductive rubber of the continuous section and the conductive rubber.

In Embodiment 3, coating rubber on the upper side of the breaker is not always necessary.

Although it is possible to adapt the mixture used for the conductive rubber to the solid portion of the conductive rubber, it is possible to use the desired mixture to provide electrical conductivity based on the tread mixture in terms of improving contact characteristics.

Side rubber

In this paper, the term "bead rubber" is a generic name for the rubber of the crimp portion or the rubber of the side ribbon. The driving force is transmitted from the drive mechanism through the rim and bead rubber, for example, crimp rubber, during tire movement, and static electricity generated in the drive mechanism accumulates inside the car and tire. It is necessary to effectively discharge static electricity through a continuous section of electrically conductive rubber in the area of contact of the tire with the road. As shown in FIG. 3, it is necessary to connect the rubber 310 of the crimp portion to the conductive rubber 39 of the continuous portion.

The volume resistivity of the bead rubber is less than 1 · 10 ⁸ Ohm · cm. If the volume resistivity of the conductive rubber is less than 1 · 10 ⁸ Ohm · cm, provide good electrical conductivity of the tire. The volume resistivity of the bead rubber is preferably less than 1 · 10 ⁷ Ohm · cm, more preferably less than 1 · 10 ⁶ Ohm · cm. Since it is necessary for the bead rubber to have good abrasion resistance, rigidity and hardness, it is possible to provide electrical resistance by formulating in the same way as for the conductive rubber of the solid portion and the conductive rubber, in addition to the above mixture composition.

The formulation of the rubber component

Coating rubber, conductive rubber of the shoulder region, conductive rubber, layer rubber, rubber of the sideband, crimp rubber, tread rubber, breaker rubber and sidewall rubber are formed from the following example rubber compositions.

Preferred examples of the rubber component include natural rubber (NR), epoxidized natural rubber, deproteinized natural rubber and diene synthetic rubber. Examples of synthetic diene rubber include styrene butadiene rubber (BSK), polybutadiene rubber (BDK), polyisoprene rubber (IR), ethylene propylene diene rubber (EPDK), chloroprene rubber (HC), butadiene acrylonitrile rubber, and BNC (B) and a rubber component containing one or more diene synthetic rubbers is suitable for use. Ethylene propylene diene rubber (EPDM) means a rubber containing ethylene propylene rubber (EPA) and a third diene component. Examples of the third diene component include a non-conjugated diene containing from 5 to 20 carbon atoms such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene and 1, 4-octadiene, or a cyclic diene, such as 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene, alkenylnorbornene, such as 5-ethylidene-2-norbornene, 2-metall-5-norbornene and 2-isopropenyl-5-norbornene, and t .P. In particular, dicyclopentadiene, 5-ethylidene-2-norbornene and the like are preferred.

As the rubber component used for the cover rubber, the conductive rubber of the shoulder region, the conductive rubber, the rubber of the layer, the rubber of the side tape and the rubber of the crimp part, diene rubber is preferred, and, among others, natural rubber (NK), styrene butadiene rubber (BSK) ), polybutadiene rubber (BDK), polyisoprene rubber (IR), and epoxidized natural rubber (ENC), deproteinized natural rubber, and the like. are preferred.

The following bonding agents, which are mainly used in rubber mixtures of tires in accordance with the requirements, can be added to the above rubber components.

In the present invention, it is preferable to add silicon dioxide to the tread rubber, the breaker rubber and the side rubber, as described above. In the case of adding silica to the rubber composition, it is necessary to add a silane-based bonding agent, it is preferable to add a sulfur-containing silane bonding agent in an amount of 1 wt.% Or more and 20 wt.% Or less by weight of silica. By adding 1% or more by weight of a silane coupling agent, the abrasion resistance of the tire is improved, thereby reducing rolling resistance. If the amount of the silane coupling agent in the mixture is 20 wt.% Or less, the risk of premature vulcanization during the stages of mixing, mixing and extrusion of rubber is reduced.

Examples of a sulfur-containing silane coupling agent include 3-trimethoxysilylpropyl-N, N-dimethylcarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazoltetrasulfide, triethoxylpropyl-metasilate-tetrasylpropylpropyl-nitropyl-propylpropyl-methylpropylmethyldimethylpropylpropylmethyldimethylpropylamino ] tetrasulfide, 3-mercaptopropyltrimethoxysilane and the like. Other useful examples of a silane coupling agent include vinyl trichlorosilane, vinyl tris (2-methoxyethoxy) silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxylpropyltrimethimethylpropyltrimethrylmethine etc.

In the present invention, it is possible to use other binding agents in accordance with the application, such as an aluminate-based bonding agent, a titanium-based bonding agent or the like, individually or in combination with a silane-based bonding agent.

Another filler may be used for the rubber component, such as carbon black, clay, alumina, talc, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium oxide, titanium oxide and the like, individually or in combination of two or more .

It is possible to add a curing agent, a vulcanization accelerator, a softener, a plasticizer, an antioxidant, a blowing agent, a vulcanization inhibitor and the like, in addition to the above substances.

An organic peroxide or sulfur-based vulcanizing agent can be used as the vulcanizing agent. Examples of organic peroxides include benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane, 2,5-dimethyl-2, 5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexin-3 or 1,3-bis (tert-butylperoxypropyl) benzene, di-tert-butylperoxy-diisopropylbenzene, tert- butyl peroxybenzene, 2,4-dichlorobenzoyl peroxide, 1,1-di-tert-butyl peroxy-3,3,5-trimethylcyloxane, n-butyl-4,4-di-tert-butyl peroxyvaleate and the like. Among the above organic peroxides, dicumyl peroxide, tert-butylperoxybenzene and di-tert-butylperoxy-diisopropylbenzene are preferred. Sulfur, morpholindisulfide and the like can be used as a sulfur-based vulcanizing agent. Among these sulfur-based vulcanizing agents, sulfur is preferred.

As a vulcanization accelerator, such substances are used that contain at least one of the sulfenamide-based vulcanization accelerators, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamine-based, aldehydeamine-based or aldehyde-ammonia-based, based on imidazoline and based on xanthate.

As an antioxidant, it is possible to choose from amine-based compounds, phenol-based, imidazole-based, carbamic acid metal salt and wax, as required.

In the present invention, a softener is used in combination to further improve the mixing processability. Examples of softeners include petroleum softeners such as process oil, lubricating oil, paraffin, paraffin oil, petroleum asphalt, petroleum jelly, softener based on fatty oils such as castor oil, linseed oil, rapeseed oil and coconut oil, waxes, such as tall oil , beeswax, carnauba wax and lanolin, fatty acids such as linoleic acid, palmitic acid, orthoxybenzoic acid and lauric acid, and the like.

Examples of plasticizers include DMF (dimethyl phthalate), DEF (diethyl phthalate), DBPt (dibutyl phthalate), DHP (diheptyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate (Bis), BID (diisodecylphthalate, Dl) (BIS) dicyclohexyl phthalate), anhydrous hydrophthalic ester, DOS (di-2-ethylhexylazelainate), DBS (dibutylsibacinate), DOS (dioctylsibacinate), acetyl triethyl citrate, acetyl tributyl citrate, DBM (dibutum dibutum) P.

Organic acids such as anhydrous phthalic acid, salicylic acid and benzoic acid, nitroso compounds such as N-nitrosodiphenylamine, N-cyclohexylthiophthalimide and the like are used as a vulcanization inhibitor to prevent or slow premature vulcanization.

The present invention will now be described in more detail in non-limiting examples.

Examples 1-3 and comparative examples 1-5

Flange rubber: crimp rubber and flange rubber

The rubber mixtures A-1, A-2 and A-3 of the bead were prepared in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in tables 1 and 2, using a sealed Banbury mixer, at a temperature of 150 ° C for 4 minutes, and then adding sulfur and a curing agent, then further mixing and stirring the mixture at 95 ° C for 2 minutes.

The manufacture of rubber layer carcass

Rubber mixtures of B-1 and B-2 carcass ply were prepared in the traditional way, mixing and mixing the components, with the exception of sulfur and a curing agent, which are presented in table 3, using a sealed Banbury mixer, at a temperature of 150 ° C for 4 min, and then adding sulfur and a vulcanizing agent, then additionally mixing and stirring the mixture at 95 ° C for 2 minutes.

Fabrication of the conductive rubber of the shoulder region, integumentary rubber and conductive rubber

Mixtures of CE conductive rubber of the shoulder region, cover rubber and conductive rubber were prepared in the traditional way, mixing and mixing the components, with the exception of sulfur and vulcanizing agent, which are presented in tables 4-6, using a sealed Banbury mixer, at a temperature of 150 ° C for 4 minutes, and then adding sulfur and a curing agent, then further mixing and stirring the mixture at 95 ° C for 2 minutes.

Tread rubber manufacturing

Rubber compounds F-1, F-2 treads were prepared in the traditional way, mixing and mixing the components, with the exception of sulfur and a curing agent, which are presented in table 7, using a sealed Banbury mixer, at a temperature of 140 ° C for 4 minutes, and then adding sulfur and a curing agent, then additionally mixing and stirring the mixture at a temperature of 95 ° C for 2 minutes

Production of sidewall rubber

Rubber mixtures of G-1 and G-2 sidewalls were prepared in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in table 8, using a sealed Banbury mixer, at a temperature of 140 ° C for 4 minutes, and then adding sulfur and a curing agent, then additionally mixing and stirring the mixture at a temperature of 95 ° C for 2 minutes

Making rubber breaker

The rubber mixtures of H-1 and H-2 breakers were prepared in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in table 9, using a sealed Banbury mixer, at a temperature of 140 ° C for 4 min, and then adding sulfur and a curing agent, then additionally mixing and stirring the mixture at a temperature of 95 ° C for 2 minutes

Table 1 Side rubber Mixture A-1 Natural rubber 80 SBR1500 twenty N220 fifty Aromatic oil 5 Wax 1,5 Antioxidant one Stearic acid 1,5 Zinc oxide 3,5 Sulfur 1,6 Accelerator 0.8 Volume resistivity (Ohm · cm) 10 ⁶ table 2 Side rubber Mixture A-2 Mixture A-3 Natural rubber 80 one hundred SBR1500 twenty - Silica VN3 - 65 Silane Coupling Agent - 6.5 N220 fifty - Aromatic oil 5 - Wax 1,5 1,5 Antioxidant one one Stearic acid 1,5 1,5 Zinc oxide 3,5 13.5 Sulfur 1,6 1.4 Accelerator 0.8 2.2 Volume resistivity (Ohm · cm) 10 ⁶ 10 ⁸ or more

Table 3 Frame Layer Rubber Mixture B-1 Mixture B-2 Natural rubber 75 75 SBR1502 25 25 N330 45 twenty Silica VN3 - 25 Si69 - 2.5 Antioxidant 2 2 Stearic acid one one Zinc oxide 3 3 Sulfur 3 3 Accelerator one one Volume resistivity (Ohm · cm) 10 ⁶ 10 ⁸ or more Table 4 Conductive Shoulder Rubber Mixture C Natural rubber 60 Polybutadiene 40 N220 45 N330 - Wax one Antioxidant 3 Stearic acid one Zinc oxide 3 Sulfur 2 Accelerator one Volume resistivity (Ohm · cm) 10 ⁶ Table 5 Cover rubber Mixture D Natural rubber 75 SBR1502 25 N220 twenty N330 25 Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 3 Accelerator one Volume resistivity (Ohm · cm) 10 ⁶

Table 6 Conductive rubber Mixture E Natural rubber thirty SBR1500 70 N220 55 Wax 1,5 Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 1.8 Accelerator one Volume resistivity (Ohm · cm) 10 ⁶ Table 7 Tread rubber Mixture F-1 Mixture F-2 SBR1500 one hundred one hundred High Wear Resistance Soot (ISAF) - fifty Vn3 fifty - Silane Coupling Agent 5 - Wax one one Antioxidant 2 2 Stearic acid one one Zinc oxide 3 3 Sulfur 1,5 1,5 Accelerator one one Volume resistivity (Ohm · cm) 10 ⁸ or more 10 ⁶ Table 8 Sidewall rubber Mixture G-1 Mixture G-2 Natural rubber 60 60 Polybutadiene 40 40 N220 45 - Silica VN3 - 45 Silane Coupling Agent - 4,5 Wax one one Antioxidant 3 3 Stearic acid one one Zinc oxide 3 3 Sulfur 2 2 Accelerator one one Volume resistivity (Ohm · cm) 10 ⁶ 10 ⁸ or more

Table 9 Breaker rubber Mixture H-1 Mixture N-2 Natural rubber one hundred one hundred N330 - 55 Silica VN3 55 - Silane Coupling Agent 5.5 - Antioxidant 2 2 Cobalt stearate 2 2 Stearic acid one one Zinc oxide 10 10 Insoluble sulfur 5.5 5.5 Accelerator 0.9 0.9 Volume resistivity (Ohm · cm) 10 ⁸ or more 10 ⁶

A detailed description of the components of the mixture from table 1-9 is presented below.

Note 1: Natural rubber is TSR20 (trade name) made in Thailand.

Note 2: SBR1500 is styrene butadiene rubber manufactured by JSR Corporation.

Note 3: SBR1502 is styrene butadiene rubber manufactured by JSR Corporation.

Note 4: Polybutadiene is BR150B (trade name) manufactured by Ube Industries, Ltd.

Note 5: N220 is carbon black manufactured by Cabot Japan K.K. (specific surface area, measured from nitrogen adsorption: 111 m ² / g; DBP oil adsorption value: 115 ml / 100 g).

Note 6: N330 is carbon black manufactured by Mitsubishi Chemical Corporation (specific surface area, measured from nitrogen adsorption: 79 m ² / g; DBP oil adsorption value: 105 ml / 100 g).

Note 7: ISAF is carbon black manufactured by Mitsubishi Chemical Corporation (specific surface area, measured from nitrogen adsorption: 115 m ² / g; DBP oil adsorption value: 114 ml / 100 g).

Note 8: Silicon dioxide VN3 is VN3 (trade name) manufactured by Degussa Corporation (specific surface area, measured from nitrogen adsorption :: 210 m ² / g).

Note 9: Silane coupling agent Si69 (trade name) manufactured by Degussa Corporation.

Note 10: Aromatic petroleum oil is X140 (trade name) manufactured by Japan Energy Corporation.

Note 11: Wax is Sunnoc N (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 12: Antistar is Antigen6C manufactured by Sumitomo Chemical Co., Ltd.

Note 13: Stearic acid, Tsubaki stearic acid (trade name) manufactured by NOF Corporation.

Note 14: Zinc oxide is zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

Note 15: Sulfur is a sulfur powder made by Karuizawa Seirensha K.K.

Note 16: The vulcanizing agent 1 is Nocceler NS-P (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 17: Insoluble sulfur is Myuclon OT20 (trade name) manufactured by Shikoku Chemicals Corporation.

Pneumatic tire manufacturing

Each of the pneumatic tires (Examples 1-3 and comparative examples 1-5) having the design shown in FIG. 1 and size 195 / 65R15 was made using rubber compounds shown in Tables 1-9 together with Tables 10 , for the tread, sidewall, breaker, rubber of the crimp part, rubber of the bead belt, conductive rubber of the shoulder region and conductive rubber, using the conventional vulcanization molding method.

The basic design of tire samples is described below.

Wireframe layer:

Cord angle: 90 degrees in the longitudinal direction of the tire.

Cord material: polyester (1800 denier).

Breaker:

Cord angle: 17 × 17 degrees in the longitudinal direction of the tire.

Cord material: 1 × 3 steel cord.

The tire of Comparative Example 2 has a structure in which the conductive rubber of the shoulder region and the conductive rubber are excluded from the structure shown in FIG. 1, and the tire of Comparative Example 3 has a structure in which the conductive rubber of the shoulder region is excluded from the structure of the tire shown in FIG. 1 . The thickness of the coating rubber was 1 mm, the thickness of the conductive rubber of the shoulder region was 1 mm, and the width of the conductive rubber was 0.5 mm and was continuous in the longitudinal direction of the tire.

Tire performance assessment

Volume resistivity

Samples were made with a thickness of 2 mm and a size of 15 cm × 15 cm using the rubber mixtures from Tables 1–9, and their volume resistivity was measured using an R8340A electrical resistance measuring device (ADVANTEST product) under conditions of a voltage of 500 V and a temperature of 25 ° C and humidity 50%. The results are presented in table 10. The higher the value, the higher the volume resistivity of the rubber compound.

Rolling resistance

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. Rolling resistance was measured using a STL rolling resistance test bench at a speed of 80 km / h and a load of 4.7 kN. The rolling resistance for comparative example 5 was taken as 100, using the coefficient of rolling resistance (SSC) obtained by dividing the registered value of rolling resistance by load, rolling resistance for examples 1-3 and comparative examples 1-4 are shown as relative values. The smaller the value, the lower the rolling resistance and the better the performance. The results are presented in table 10.

Bus conductivity

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. The tread of each tire was brought into contact with an iron plate at a load of 4.7 kN in order to measure the electrical resistance between the tire rim and the metal plate at an applied voltage of 100 V. The results are presented in Table 10.

Table 10 Example 1 Example 2 Example 3 Compare-
full
example
one Compare-
full
example 2 Compare-
full
example 3 Compare-
full
example 4 Compare-
full
example 5 Type of mixture Tread rubber F-1 F-1 F-1 F-1 F-1 F-1 F-1 F-2 Sidewall rubber G-2 G-2 G-2 G-2 G-2 G-1 G-2 G-1 Breaker rubber N-1 N-1 N-1 N-1 N-2 N-1 N-1 N-2 Conductive rubber E E E E - E E E Cover rubber D D D D D D D D Conductive Shoulder Rubber FROM FROM FROM FROM - - FROM - Frame Layer Rubber IN 1 IN 1 IN 1 IN 2 IN 1 IN 1 IN 1 IN 1 Side belt rubber A-1 A-3 A-3 A-1 A-1 A-1 A-3 A-3 Crimp rubber A-3 A-2 A-3 A-3 A-3 A-3 A-3 A-3 Rubber side tape A-3 A-3 A-2 A-3 A-3 A-3 A-3 A-3 Bus conductivity 2.2 × 10 ⁶ 4.0 × 10 ⁶ 3.0 × 10 ⁶ > 10 ⁸ 4.1 × 10 ⁶ 3.7 × 10 ⁶ > 10 ⁸ > 10 ⁸ Rolling resistance 74 75 75 76 75 80 72 one hundred

As can be seen from table 10, comparative example 1 is inferior in electrical conductivity of the tire, since a rubber mixture with low electrical conductivity was used for the rubber of the carcass ply. Comparative example 2 is inferior in tire electrical conductivity, since a rubber mixture with low electrical conductivity was used for the breaker rubber, and the conductive rubber and the conductive rubber of the shoulder region were absent. Comparative example 3 is inferior in electrical conductivity to the tire, since a rubber mixture with high electrical conductivity was used for sidewall rubber and a layer of conductive rubber was excluded. Comparative example 4 is inferior in electrical conductivity of the tire, because they used a rubber mixture with low electrical conductivity for rubber on-board tape.

In examples 1-3, an improvement in the rolling resistance and electrical conductivity of the tire was achieved, since an electrically conductive rubber mixture having a volume resistivity of 6.1 · 10 ⁶ Ohm · m was used for the structural element of the tire, and the volume resistivity of the belt and sidewall was set to 1 · 10 ⁸ Ohm · m or more, from which it becomes clear that the pneumatic tire in accordance with the present invention is the best both in rolling resistance and electrical conductivity.

Examples 4 and 5 and comparative examples 6-9

Flange Rubber: Flange Rubber

With the exception of sulfur and a curing agent, all the components of the mixture shown in Table 11 were mixed and mixed using a Banbury hermetic mixer at 150 ° C for 4 minutes, and then sulfur and a curing agent were added, then the mixture was further mixed and mixed at a temperature 95 ° C for 2 minutes, then the extrusion stage and the calendering stage were carried out in accordance with the traditional method to prepare mixtures of A1-1, A1-2, A1-3 rubber of the side ribbon.

The manufacture of rubber layer carcass

With the exception of sulfur and a curing agent, all the components of the mixture shown in Table 12 were mixed and mixed using a Banbury hermetic mixer at 150 ° C for 4 minutes, and then sulfur and a curing agent were added, then the mixture was further mixed and mixed at temperature of 95 ° C for 2 min, then the extrusion stage and the calendering stage were performed in accordance with the traditional method to prepare mixtures of B1-1, B1-2, B1-3 rubber of the carcass layer.

Fabrication of the conductive rubber of the shoulder region, integumentary rubber and conductive rubber

With the exception of sulfur and a curing agent, all the components of the mixture shown in Tables 13-15 were mixed and mixed using a Banbury hermetic mixer at 150 ° C for 4 minutes, and then sulfur and a curing agent were added, then they were further mixed and mixed the mixture at a temperature of 95 ° C for 2 minutes, then the extrusion step and the calendaring step were carried out in accordance with the traditional method to prepare the C1-E1 mixture of the conductive rubber of the shoulder region, coating rubber and conductive rubber.

Tread rubber manufacturing

With the exception of sulfur and a curing agent, all the components of the mixture shown in Table 16 were mixed and mixed using a Banbury hermetic mixer at 140 ° C for 4 minutes, and then sulfur and a curing agent were added, then the mixture was further mixed and mixed at at a temperature of 95 ° C for 2 minutes, then an extrusion step and a calendaring step were carried out in accordance with a conventional method to prepare a mixture of F1 tread rubber.

Production of sidewall rubber

With the exception of sulfur and a curing agent, all the components of the mixture shown in Table 17 were mixed and mixed using a Banbury hermetic mixer at 140 ° C for 4 minutes, and then sulfur and a curing agent were added, then the mixture was further mixed and mixed at at a temperature of 95 ° C for 2 minutes, then an extrusion step and a calendaring step were carried out in accordance with a conventional method to prepare a mixture of G1 and G2 of the sidewall rubber.

Making rubber breaker

With the exception of sulfur and a curing agent, each of the components of the mixture shown in Table 18 was mixed and mixed using a Banbury hermetic mixer at 140 ° C for 4 minutes, and then sulfur and a curing agent were added, then the mixture was further mixed and mixed at at a temperature of 95 ° C for 2 minutes, then an extrusion step and a calendering step were carried out in accordance with the traditional method to prepare mixtures of H1-1 and H1-2 of rubber breaker.

Table 11 Side tape Mixture A1-1 Mixture A1-2 Mixture A1-3 Natural rubber twenty twenty twenty SBR1500 80 80 80 N220 fifty - - Silica VN3 - fifty fifty Silane Coupling Agent (Si69) - 5 5 Aromatic oil 5 5 5 Wax 1,5 1,5 1,5 Antioxidant one one one Stearic acid 1,5 1,5 1,5 Zinc oxide 3,5 3,5 3,5 Sulfur 1,6 1,6 1,6 Accelerator 0.8 0.8 0.8 Volume resistivity (Ohm · cm) 1 · 10 ⁶ 1 · 10 ⁶ 1 · 10 ⁸ or more

Table 12 Rubber layer Mixture B1-1 Mixture B1-2 Mixture B1-3 Natural rubber 75 75 75 SBR1502 25 25 25 N330 45 - - Silica VN3 - 45 45 Silane Coupling Agent (Si69) - 4,5 4,5 Antioxidant 2 2 2 Stearic acid one one one Zinc oxide 3 3 3 Sulfur 3 3 3 Accelerator one one one Metal foil - 2 - Volume resistivity (Ohm · cm) 1 · 10 ⁶ 1 · 10 ⁶ 1 · 10 ⁸ or more Table 13 Conductive Shoulder Rubber Mixture C1 Natural rubber 60 Polybutadiene 40 Silica VN3 45 Silane Coupling Agent (Si69) 4,5 Wax one Antioxidant 3 Stearic acid one Zinc oxide 3 Sulfur 2 Accelerator one Metal foil 2 Volume resistivity (Ohm · cm) 1 · 10 ⁶ Table 14 Cover rubber Mixture D1 Natural rubber 75 BSK1502 25 Silica VN3 twenty Silane Coupling Agent (Si69) 25 Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 3 Accelerator one Metal foil 2 Volume resistivity (Ohm · cm) 1 · 10 ⁶

Table 15 Conductive rubber Mixture E1 Natural rubber thirty SBR1500 70 Silica VN3 55 Silane Coupling Agent (Si69) 5.5 Wax 1,5 Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 1.8 Accelerator one Metal foil 2 Volume resistivity (Ohm · cm) 1 · 10 ⁶ Table 16 Tread rubber Mixture F1 SBR1500 one hundred Silica VN3 fifty Silane Coupling Agent (Si69) 5 Wax one Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 1,5 Accelerator one Volume resistivity (Ohm · cm) 1 · 10 ⁸ or more Table 17 Sidewall rubber Mixture G1-1 Mixture G 1-2 Natural rubber 60 60 Polybutadiene 40 40 N220 45 - Silica VN3 - 45 Silane Coupling Agent (Si69) - 4,5 Wax one one Antioxidant 3 3 Stearic acid one one Zinc oxide 3 3 Sulfur 2 2 Accelerator one one Volume resistivity (Ohm · cm) 1 · 10 ⁶ 1 · 10 ⁸ or more

Table 18 Breaker rubber Mixture H2-1 Mixture H2-2 Natural rubber one hundred one hundred N330 - 55 Silica VN3 55 - Silane Sizing (Si69) 5.5 - Antioxidant 2 2 Cobalt stearate 2 2 Stearic acid one one Zinc oxide 10 10 Insoluble sulfur 5.5 5.5 Accelerator 0.9 0.9 Volume resistivity (Ohm · cm) 1 · 10 ⁸ or more 1 · 10 ⁶

A detailed description of the components of the mixture from table 11-18 is presented below.

Note 1: Natural rubber is TSR20 (trade name) made in Thailand.

Note 2: SBR1500 is styrene butadiene rubber manufactured by JSR Corporation.

Note 3: SBR1502 is styrene butadiene rubber manufactured by JSR Corporation.

Note 4: Polybutadiene - BR150B (trade name) manufactured by Ube Industries, Ltd.

Note 5: N220 is carbon black manufactured by Cabot Japan K.K. (specific surface area, measured from nitrogen adsorption: 111 m ² / g; DBP oil adsorption value: 115 ml / 100 g).

Note 6: N330 is carbon black manufactured by Mitsubishi Chemical Corporation (specific surface area, measured from nitrogen adsorption: 79 m ² / g; DBP oil adsorption value: 105 ml / 100 g).

Note 7: Silicon dioxide VN3 - VN3 (trade name) manufactured by Degussa Corporation (specific surface area, measured from nitrogen adsorption: 210 m ² / g).

Note 8: Si69 silane coupling agent (trade name) manufactured by Degussa Corporation.

Note 9: Aromatic Petroleum Oil - X140 (trade name) manufactured by Japan Energy Corporation.

Note 10: Wax - Sunnoc N (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 11: Antigen6C Antistar manufactured by Sumitomo Chemical Co., Ltd.

Note 12: Stearic acid, Tsubaki stearic acid (trade name) manufactured by NOF Corporation.

Note 13: Zinc oxide is zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

Note 14: Sulfur is a sulfur powder made by Karuizawa Seirensha K.K.

Note 15: Vulcanizing agent 1- Nocceler NS-P (trademark) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 16: Insoluble Sulfur, Myuclon OT20 (trade name) manufactured by Shinko Chemical Industrial Co., Ltd.

Note 17: The metal foil has a thickness of 10 to 50 μm, a smallest diameter of 0.1 to 9.3 mm and a largest diameter of 0.2 to 0.5 mm.

Pneumatic tire manufacturing

Each of the pneumatic tires (Examples 4 and 5 and comparative examples 6-9), having the structure shown in FIG. 1, and size 195 / 65R15, was made using rubber compounds shown in Tables 11-18 together with Tables 19-18. for the tread, sidewall, breaker, rubber of the crimp portion, rubber of the bead belt, conductive rubber of the shoulder region and conductive rubber using the conventional method of vulcanization in the mold.

Basic design of tire samples as described below.

Wireframe layer:

Cord angle: 90 degrees in the longitudinal direction of the tire.

Cord material: polyester fiber (1670 dtex / 2).

Breaker:

Cord angle: 24 × 24 degrees in the longitudinal direction of the tire.

Cord material: steel cord (2 + 2 × 0.25).

The mixture (B1-3) with increased volume resistivity is used for the rubber of the carcass ply in comparative example 6, and in comparative example 7, the shoulder conductive rubber and the conductive rubber are excluded from the structure shown in FIG. 1. In comparative example 3, the conductive rubber of the shoulder region is excluded from the tire structure shown in FIG. 1. The mixture (A1-3) with a high volume resistivity is used for rubber on-board tape in comparative example 9.

The thickness of the coating rubber was 1 mm, the thickness of the conductive rubber of the shoulder region was 1 mm, and the width of the conductive rubber was 3 mm and was continuous in the longitudinal direction of the tire.

Tire performance assessment

Volume resistivity

Samples were made with a thickness of 2 mm and a size of 15 cm × 15 cm using the rubber mixtures from Tables 11-18, and their volume resistivity was measured using an R8340A electrical resistance measuring device (ADVANTEST product) under conditions: voltage 500 V, temperature 25 ° C and humidity 50%. The results are presented in table.19. The larger the value, the higher the volume resistivity of the rubber compound.

Rolling resistance

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. Rolling resistance was measured using a STL rolling resistance test bench at a speed of 80 km / h and a load of 4.7 kN. The rolling resistance for comparative example 6 was taken as 100, using the coefficient of rolling resistance (SSC) obtained by dividing the registered value of rolling resistance by load, rolling resistance for examples 4 and 5 and comparative examples 7-9 are shown as relative values. The smaller the value, the lower the rolling resistance and the better the performance. The results are presented in table.19.

Bus conductivity

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. The tread of each tire was brought into contact with an iron plate at a load of 4.7 kN in order to measure the electrical resistance between the tire rim and the metal plate at an applied voltage of 100 V. The results are presented in Table 19.

Table 19 Example 4 Example 5 Comparison
ny
example 6 Comparison
ny
example 7 Comparison
ny
example 8 Comparison
ny
example 9 Type of mixture Tread rubber F F F F F F Sidewall rubber G-2 G-2 G-2 G-2 G-1 G-2 Breaker rubber N-1 N-1 N-1 N-2 N-1 N-1 Conductive rubber E E E - E E Cover rubber D D D D D D Conductive Shoulder Rubber FROM FROM FROM - - FROM Rubber layer IN 1 IN 2 IN 3 IN 1 IN 1 IN 1 Side belt rubber A-1 A-2 A-1 A-1 A-1 A-3 Bus conductivity 2.2 × 10 ⁶ 2.2 × 10 ⁶ > 10 ⁸ 4.1 × 10 ⁶ 3.7 × 10 ⁶ > 10 ⁸ Rolling resistance one hundred 98 one hundred 102 101 101

As can be seen from table 19, comparative example 6 is inferior in bus conductivity, since a rubber mixture with low conductivity was used for the rubber layer. Comparative Example 7 is inferior in electrical conductivity to the tire, since a rubber mixture with low electrical conductivity was used for the belt rubber, and since the conductive rubber and the conductive rubber of the shoulder region were excluded. Comparative example 8 is inferior in electrical conductivity to the tire, since a rubber mixture with high electrical conductivity was used for sidewall rubber and since a layer of conductive rubber is excluded. Comparative example 9 is inferior in electrical conductivity to the tire, since a rubber mixture with low electrical conductivity was used for rubber on-board tape.

In both examples 4 and 5, a decrease in rolling resistance was achieved and the electrical conductivity of the tire was improved, since they used an electrically conductive rubber mixture having a volume resistivity of 6.1 × 10 ⁶ Ohm · m for the structural element of the tire, and since the volume resistivity of the tread, belt and the sidewalls were set to 1.0 × 10 ⁸ Ω · m or more, from which it became clear that in the pneumatic tire in accordance with the present invention, it is possible to achieve a reduction in rolling resistance and excellent electrical conductivity.

Examples 6 and 7 and comparative examples 10 and 11

The manufacture of conductive rubber of the side, coating rubber and conductive rubber

With the exception of sulfur and a curing agent, all the components of the mixture shown in Table 20 were mixed and mixed using a Banbury hermetic mixer at 150 ° C for 4 minutes, sulfur and a curing agent were added, mixed and mixed at 95 ° C in for 2 minutes, then the extrusion step and the calendaring step were carried out in accordance with the conventional method to prepare a mixture of C2-E2 layer rubber, side conductive rubber, coating rubber and conductive rubber.

Production of tread rubber, sidewall rubber, breaker rubber and crimp rubber

With the exception of sulfur and a curing agent, all components of the mixture shown in Tables 21-24 were mixed and mixed using a Banbury hermetic mixer at 150 ° C for 4 minutes, sulfur and a curing agent were added, mixed and mixed at 95 ° C for 2 minutes, then the extrusion step and the calendaring step were carried out in accordance with the traditional method to prepare the tread rubber mixtures F.

Table 20 Mixture Cover rubber / conductive rubber Side Conductive Rubber A2 IN 2 C2 D2 E2 F2 G2 H2 Diene Based Rubber NR (brand TSR20) one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Soot N330 (products of Mitsubishi Chemical Corporation) 55 - - - fifty - - - Silica VN3 (Degussa Corporation products) - 55 fifty 40 - fifty 45 35 Soot Printex XE2B (Degussa Corporation products) - - 5 fifteen - - 5 fifteen Process oil Diana Process PS32 (Idemitsu Kosan Co., Ltd. products) 5 - - - 10 - - - Soybean oil Refined Soybean Oil (Nissan Oillio Group, Ltd. Products) - 5 5 5 - 10 10 10 Wax Sunnoc Wax (Ouchi Shinko Chemical Industrial Co., Ltd.) 2 2 2 2 - - - - Antioxidant Sunflex 13 (Flexsys products) 2 2 2 2 four four four four Stearic acid Kiri (NOF products) 2 2 2 2 2 2 2 2 Zinc oxide Zinc oxide No. 1 (products of Mitsui Mining & Smelting Co., Ltd.) 5 5 5 5 5 5 5 5 Silane Coupling Agent Si75 (Degussa Corporation products) - 5 four 3 - 5 four 3 Sulfur Crystex HSOT20 (Flexsys products) 5 5 5 5 1,5 1,5 1,5 1,5 Vulcanizing agent Nocceler (Ouchi Shinko Chemical Industrial Co., Ltd. products) 2 2 2 2 0.75 0.75 0.75 0.75 Volume resistivity (Ohm · cm) log ₁₀ R 4.8 10.5 7.8 5.8 5,0 11.1 7.1 5.3 The ratio of materials derived from non-petroleum feedstocks (%) 63 94 92 87 63 95 92 87

In table 20, the specific surface area of carbon black (Printex XE2B) by the method of nitrogen adsorption is 880 m ² / g.

Table 21 Crimp rubber Mixture I2 Natural rubber twenty SBR1500 80 N220 fifty Aromatic oil 5 Wax 1,5 Antioxidant one Stearic acid 1,5 Zinc oxide 3,5 Sulfur 1,6 Accelerator 0.8 Volume resistivity (Ohm · cm) 1 · 10 ⁶ Table 22 Tread rubber Mixture J2 Natural rubber one hundred Silica VN3 fifty Silane Coupling Agent 5 Wax one Antioxidant 2 Stearic acid one Zinc oxide 3 Sulfur 1,5 Accelerator one Volume resistivity (Ohm · cm) 1 · 10 ¹¹ Table 23 Sidewall rubber Mixture K2 Natural rubber one hundred Silica VN3 45 Silane Coupling Agent 4,5 Wax one Antioxidant 3 Stearic acid one Zinc oxide 3 Sulfur 2 Accelerator one Volume resistivity (Ohm · cm) 1 · 10 ¹¹

Table 24 Breaker rubber Mixture L2 Natural rubber one hundred N330 - Silica VN3 55 Silane Coupling Agent 5.5 Antioxidant 2 Cobalt stearate 2 Stearic acid one Zinc oxide 10 Insoluble sulfur 5.5 Accelerator 0.9 Volume resistivity (Ohm · cm) 1 · 10 ¹¹

A detailed description of the components of the mixture from table.21-24 is presented below.

Note 1: Natural rubber - TSR20 (trade name), made in Thailand.

Note 2: SBR1500 is styrene butadiene rubber manufactured by JSR Corporation.

Note 3: N220 is carbon black manufactured by Cabot Japan KK (specific surface from nitrogen adsorption: 111 m ² / g; DBP oil adsorption value: 115 ml / 100 g).

Note 4: N330 is carbon black manufactured by Mitsubishi Chemical Corporation (specific surface for nitrogen adsorption: 79 m ² / g; DBP oil adsorption value: 105 ml / 100 g).

Note 5: Silicon dioxide VN3 - VN3 (trade name) manufactured by Degussa Corporation (specific surface from nitrogen adsorption: 210 m ² / g).

Note 6: Silane coupling agent is Si69 (trade name) manufactured by Degussa Corporation.

Note 7: Aromatic petroleum oil - X140 (trademark) manufactured by Japan Energy Corporation.

Note 8: Wax - Sunnoc N (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 9: Antioxidant - Antigen6C manufactured by Sumitomo Chemical Co., Ltd.

Note 10: Stearic acid is Tsubaki stearic acid (trade name) manufactured by NOF Corporation.

Note 11: Zinc oxide is zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

Note 12: Sulfur is a sulfur powder manufactured by Karuizawa Seirensha K.K.

Note 13: Vulcanizing agent 1 - Nocceler NS-P (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 14: Insoluble Sulfur - Myuclon OT20 (trade name) manufactured by Shikoku Chemical Corporation.

Each of the pneumatic tires (Examples 6 and 7 and comparative examples 10 and 11), having the structure shown in Figure 2, and size 195 / 65R15, were made using rubber compounds shown in table 20-24 together with table 25 for the tread, sidewall, breaker, rubber of the crimp, rubber of the bead tape, conductive rubber of the shoulder region and conductive rubber, using the conventional method of vulcanization in the mold. The basic design of tire samples is described below.

Wireframe layer:

Cord angle: 90 degrees in the longitudinal direction of the tire.

Cord material: polyester fiber (1500 denier, 1670 dtex / 2).

Breaker:

Cord angle: 24 × 24 degrees in the longitudinal direction of the tire.

Cord Material: Steel.

The thickness of the coating rubber was 0.8 mm, the thickness of the conductive rubber of the side part was 1 mm, and the width of the conductive rubber was 1.5 mm and was continuous in the tire longitudinal direction.

Tire performance assessment

Volume resistivity

Samples were made with a thickness of 2 mm and a size of 15 cm × 15 cm using the rubber mixtures from Tables 20-24, and their volume resistivity was measured using an R8340A electrical resistance tester (product ADVANTEST) under conditions: voltage 500 V, temperature 25 ° C and humidity 50%. The results are presented in table 20-24. The larger the value, the higher the volume resistivity of the rubber compound.

Rolling resistance

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 2 MPa. Rolling resistance was measured using a STL rolling resistance test bench at a speed of 80 km / h and a load of 4.7 kN. Using the coefficient of rolling resistance (KSK) obtained by dividing the registered value of rolling resistance by load, the rolling resistance of examples 6 and 7 and comparative examples 10 and 11 were obtained according to the following equality:

Rolling resistance = coefficient of rolling resistance of comparative example 1 / rolling resistance of each of examples 6 and 7 and comparative example 11 × 100, with rolling resistance of comparative example 10 taken as 100. The lower the value, the lower the rolling resistance and better performance. The results are presented in table.25.

Bus conductivity

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 2 MPa. The tread of each tire was brought into contact with an iron plate at a load of 4.7 kN in order to measure the electrical resistance between the tire rim and the metal plate at an applied voltage of 100 V. The results are presented in Table 25.

Table 25 Example 6 Example 7 Reference Example 10 Reference Example 11 Subprotector FROM D BUT AT Conductive rubber FROM D BUT AT Side Conductive Rubber G H E F Crimp rubber I I I I Tread rubber J J J J Sidewall rubber K K K K Breaker rubber L L L L Bus conductivity 1 · 10 ⁷ 1 · 10 ⁶ 1 · 10 ⁷ 1 · 10 ¹¹ Rolling resistance 106 104 one hundred 103

As can be seen from table 25, comparative example 10 does not contain silicon dioxide and conductive carbon black in the coating rubber, conductive rubber and conductive rubber of the side. Comparative example 11 does not contain soot in the coating rubber, the conductive rubber and the conductive rubber of the side portion.

In both examples 6 and 7, an improvement in the rolling resistance and electrical conductivity of the tire was achieved, since an electrically conductive rubber mixture having a volume resistivity of 1 · 10 ⁸ Ohm · cm was used for coating rubber, conductive rubber and side conductive rubber, and since volume resistivity the rubber of the tread, the breaker and the sidewalls were set to 1 · 10 ⁸ Ohm · cm or more, from which it becomes clear that in the pneumatic tire in accordance with the present invention it is possible to achieve as excellent value, and good electrical conductivity.

Examples 8 and comparative examples 12-17

The manufacture of conductive rubber solid area and conductive rubber compound

The mixtures for the conductive rubber of the continuous section and the conductive rubber A3-C3 were made in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in table 26, using a sealed Banbury mixer, at a temperature of 150 ° C for 4 minutes, and then sulfur and a curing agent were added, followed by further mixing and stirring of the mixture at 95 ° C for 2 minutes.

Tread rubber manufacturing

D3 tread rubber mixtures were made in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in table 26, using a sealed Banbury mixer, at a temperature of 140 ° C for 4 minutes, and then sulfur and a vulcanizing agent were added. followed by additional mixing and stirring of the mixture at a temperature of 95 ° C for 2 minutes

Production of sidewall rubber

Rubber mixtures of E3 and F3 sidewalls were made in the traditional way, by mixing and mixing the components, except for sulfur and a curing agent, which are presented in table 26, using a sealed Banbury mixer at a temperature of 140 ° C for 4 min, and then sulfur and curing agent, followed by further mixing and stirring of the mixture at a temperature of 95 ° C for 2 minutes

Making rubber breaker

The rubber mixtures G3 and H3 of the breaker were made in the traditional way by mixing and mixing the components, with the exception of sulfur and a vulcanizing agent, which are presented in table 26, using a sealed Banbury mixer, at a temperature of 140 ° C for 4 min, and then sulfur and vulcanizing agent, followed by further mixing and stirring of the mixture at a temperature of 95 ° C for 2 minutes

Crimp rubber manufacturing

Mixtures of I3 and J3 rubber of the crimp part were made in the traditional way by mixing and mixing the components, except for sulfur and a curing agent, which are presented in table 26, using a sealed Banbury mixer at a temperature of 140 ° C for 4 min, and then sulfur was added and curing agent, followed by further mixing and stirring of the mixture at a temperature of 95 ° C for 2 minutes

Measurement of volume resistivity of a rubber compound

The volume resistivity of the rubber compounds A3-J3 was measured after molding by vulcanization at 150 ° C for 30 minutes, and the results are presented in table.26.

Table 26 Conductive Rubber / Conductive Rubber Rubber tread
ra Sidewall rubber Breaker rubber Crimp rubber Type of mixture A3 IN 3 C3 D3 E3 F3 G3 H3 I3 J3 Natural rubber (Note 1) one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Wood tar carbon black (Note 2) 45 twenty - - - 45 - 55 thirty - Silicon Dioxide VN3 (Note 3) - - 45 fifty 45 - 55 - 60 90 Silane coupling agent (Note 4) - - - 5 4,5 - 5.5 - 6 9 Wax (Note 5) one one one one one one - - one one Antioxidant (Note 6) 3 3 3 2 3 3 2 2 3 3 Cobalt stearate - - - - - - 2 2 - - Stearic acid (Note 7) one one one one one one one one one one Zinc Oxide (Note 8) 3 3 3 3 3 3 10 10 3 3 Sulfur (Note 9) 2 2 2 1,5 2 2 5.5 (Note 11) 5.5 (Note 11) 2 2 Accelerator (Note 10) one one one one one one 0.9 0.9 3 3 Volume resistivity (Ohm · cm) 10 ⁶ 10 ⁷ 10 ⁸
or more 10 ⁸
or more 10 ⁸
or more 10 ⁶ 10 ⁸
or more 10 ⁶ 10 ⁶ 10 ⁸
or more

Note 1: Natural rubber - TSR20 (trade name), made in Thailand.

Note 2: Charcoal tar soot was obtained in a liquid fuel furnace using charcoal tar formed as a by-product of charcoal processing as a raw material. The specific surface area, measured from nitrogen adsorption, is 125 m ² / g and the DBP oil adsorption value is 105 ml / 100 g.

Note 3: Silicon dioxide VN3 - VN3 (trade name) manufactured by Degussa Corporation (specific surface area, measured from nitrogen adsorption: 210 m ² / g).

Note 4: Silane coupling agent is Si69 (trade name) manufactured by Degussa Corporation.

Note 5: Wax - Sunnoc N (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 6: Antioxidant - Antigen6C manufactured by Sumitomo Chemical Co., Ltd.

Note 7: Stearic acid, Tsubaki stearic acid (trade name) manufactured by NOF Corporation.

Note 8: Zinc Oxide is zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

Note 9: Sulfur is a sulfur powder made by Karuizawa Seirensha K.K.

Note 10: The vulcanizing agent 1 is Nocceler NS-P (trade name) manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

Note 11: Insoluble sulfur, Myuclon OT20 (trade name) manufactured by Shikoku Chemicals Corporation.

Pneumatic tire manufacturing

Each of the pneumatic tires (example 8 and comparative examples 12, 13 and 17) having the structure shown in FIG. 3 and size 195 / 65R15, and each of the pneumatic tires (comparative examples 14-16) having the structure presented on 4, and size 195 / 65R15, were made using the rubber mixtures shown in Table 27 for the tread, sidewall, breaker, crimp rubber, solid conductive rubber, and conductive rubber using a conventional vulcanization molding method.

The conductive rubber and the conductive rubber of the solid portion are formed on the tire shown in FIG. 3, and these elements are not formed on the tire shown in FIG. 4. 3, the thickness of the conductive rubber of the continuous section is 1.0 mm, and the conductive rubber of the continuous section is continuous in the longitudinal direction of the tire.

Volume resistivity

Samples were made with a thickness of 2 mm and a size of 15 cm × 15 cm using the rubber mixtures from Table 26, and their volume resistivity was measured using an R8340A electrical resistance measuring device (ADVANTEST product) under conditions: voltage 500 V, temperature 25 ° С and humidity 50%. The results are presented in table.26. The larger the value, the higher the volume resistivity of the rubber compound.

Rolling resistance

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. Rolling resistance was measured using a STL rolling resistance test bench at a speed of 80 km / h and a load of 4.7 kN. The rolling resistance of comparative example 12 was taken as 100, using the coefficient of rolling resistance (KSK) obtained by dividing the obtained value of rolling resistance by load, the rolling resistance of example 8 and comparative examples 12-17 are shown as relative values. The smaller the value, the lower the rolling resistance and the better the performance. The results are presented in table.27.

Bus conductivity

Pneumatic tires manufactured as described above were mounted on standard rims and then inflated to a standard pressure of 200 kPa. The tread of each tire was brought into contact with an iron plate at a load of 4.7 kN in order to measure the electrical resistance between the tire rim and the metal plate at an applied voltage of 100 V. The results are presented in Table 27.

Table 27 Example 8 Compare-
full
example
12 Compare-
full
example 13 Compare-
full
example 14 Compare-
full
example 15 Compare-
full
example 16 Compare-
full
example 17 Type of mixture Tread rubber D3 D3 D3 D3 D3 D3 D3 Sidewall rubber E3 E3 E3 E3 F3 F3 E3 Breaker rubber G3 G3 G3 G3 G3 H3 G3 Continuous Conductive Rubber A3 IN 3 C3 - - - A3 Conductive rubber A3 IN 3 C3 - - - A3 Crimp rubber I3 I3 I3 I3 I3 I3 J3 Tire design Figure 3 Figure 3 Figure 3 Figure 4 Figure 4 Figure 4 Figure 3 Rolling resistance one hundred one hundred one hundred one hundred 104 105 one hundred Bus Conductivity (Electrical Resistance) 6.1 × 10 ⁶ 10 ⁸ or more 10 ⁸ or more 10 ⁸ or more 10 ⁸ or more 5.6 × 10 ⁶ 10 ⁸ or more The ratio of materials derived from non-petroleum feedstocks 80% or more 80% or more 80% or more 80% or more 75% or less 75% or less 80% or more

As can be seen from table 27, in comparative examples 12 and 13 do not realize the improvement of the electrical conductivity of the tire, since the volume resistivity of the rubber mixture used for the conductive rubber of the continuous section is not sufficiently reduced. Also, if the volume resistivity of the rubber composition used for the conductive rubber is sufficiently reduced, as in comparative example 17, the tire conductivity becomes insufficient if the conductivity of the rubber of the crimp portion is low. Comparative examples 13-16 are based on a conventional tire design (a schematic section of which is shown in FIG. 4), and comparative example 14 is inferior in electrical conductivity, while the rolling resistance of examples 15 and 16 is not enough.

In contrast, in Example 8, both rolling resistance and tire conductivity were improved, since an electrically conductive solid rubber mixture was formed having a specific volume resistance of 6.1 · 10 ⁶ Ohm · cm and a specific volume resistance of tread rubber, breaker and sidewall 1 · 10 ⁸ Ohm · cm or more was installed, from which it is clear that the pneumatic tire in accordance with the present invention has excellent characteristics of both rolling resistance and electrical conductivity.

The pneumatic tire of the present invention, in which it is possible to suppress rolling resistance and effectively discharge static electricity generated during movement, is suitable for use in vehicles such as cars, trucks, buses and heavy equipment.

Although the present invention has been described and illustrated in detail, it is obvious that the examples and drawings provided are for illustration only and do not limit the scope of the present invention set forth in the appended claims.

Claims (14)

1. A pneumatic tire including a tread, a sidewall, a bead, a carcass extending from said tread to a specified bead through said sidewall, and a belt located on the outer side of said carcass in the radial direction of the tire, in which the tread rubber, the breaker rubber and the sidewall rubber, formed respectively on said tread, said breaker and said sidewall, have a volume resistivity of 1 · 10 ⁸ Ω · cm or more,
moreover, the specified pneumatic tire further includes a conductive rubber embedded in the tread so that the specified conductive rubber at least partially extends to the surface of the specified tread, bead rubber located in the contact area of the bead of the rim with the tire bead, and an electrically conductive rubber electrically connecting the specified conductive rubber with the specified rubber side, where
said conductive rubber, said tread rubber and said conductive rubber have a specific resistance of less than 1 · 10 ⁸ Ohm · cm. 2. The pneumatic tire according to claim 1, in which the specified bead rubber is a rubber crimp part or rubber side tape. 3. The pneumatic tire according to claim 1, wherein said conductive rubber is formed continuously in the longitudinal direction of the tire. 4. The pneumatic tire according to claim 1, wherein said conductive rubber has a thickness of 0.2 to 2 mm. 5. A pneumatic tire including a tread, a sidewall, a bead, a carcass extending from said tread to a specified bead through said sidewall, and a belt located on the outside of said carcass in the radial direction of the tire, in which the tread rubber, the breaker rubber and the sidewall rubber, formed respectively on the specified tread, the specified broker and the specified sidewall, have a volume resistivity of 1 · 10 ⁸ Ohm · cm or more,
moreover, the specified pneumatic tire further includes a conductive rubber of the shoulder area located at the lower part of both edges of the specified broker, a coating rubber covering the upper part of the specified breaker and having an area of at least 5 mm for contact with the specified conductive rubber of the shoulder area, the conductive rubber, in contact with the coating rubber and embedded in the specified tread so that the specified conductive rubber at least partially extends to the surface of the tread, and p zine side contacting the lower end of said frame and disposed in contact with the bead of the rim bead of the tire, wherein
the rubber of the layer forming the specified frame, the specified conductive rubber of the shoulder area, the specified coating rubber, the specified conductive rubber and the specified bead rubber have a specific resistance of less than 1 · 10 ⁸ Ohm · cm. 6. The pneumatic tire according to claim 5, wherein at least one of the elements comprising said layer rubber forming a carcass, said shoulder conductive rubber, said cover rubber, said bead rubber and said bead rubber comprises a metal foil or electrically conductive soot . 7. The pneumatic tire according to claim 5, wherein said layer rubber, said shoulder conductive rubber, said cover rubber, said bead rubber and said bead rubber contain soot with a specific surface area measured from nitrogen adsorption of 100 m ² / g or more, in an amount of from 30 to 100 parts by weight per 100 parts by weight rubber component. 8. The pneumatic tire according to claim 7, in which the specified rubber layer, the specified conductive rubber of the shoulder area, the specified coating rubber, the specified conductive rubber and the specified bead rubber contain metal foil in an amount of from 1 to 10 parts by weight per 100 parts by weight rubber component. 9. A pneumatic tire including a tread, a sidewall, a bead, a carcass extending from the specified tread to the specified bead through the specified sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, in which
tread rubber, broker rubber and sidewall rubber, respectively formed on said tread, said breaker and said sidewall, have a volume resistivity of 1 · 10 ⁸ Ω · cm or more,
wherein said pneumatic tire further includes an electrically conductive rubber of a side portion extending from at least both edges of said belt to a board along an outer side of said chassis;
a coating rubber having an area for contacting said lateral conductive rubber and located so that said coating rubber covers the upper part of the breaker; conductive rubber in contact with the coating rubber and embedded in said tread in such a way that said conductive rubber partially extends to the tread surface; and bead rubber in contact with the lower end of said lateral conductive rubber and located in the contact region of the bead of the rim with the tire bead, where
the specified conductive rubber of the side, the specified coating rubber and the specified conductive rubber contain carbon black with a specific surface area measured from nitrogen adsorption of 600 m ² / g or more, in an amount of 5 wt.h. or more per 100 parts by weight the rubber component and silicon dioxide with a specific surface area measured from nitrogen adsorption of 70 m ² / g or more and 250 m ² / g or less, in an amount of from 10 to 55 parts by weight per 100 parts by weight rubber component, and each rubber has a volume resistivity of less than 1 · 10 ⁸ Ohm · cm. 10. The pneumatic tire according to claim 9, wherein said carbon black is “Ketjen Black” carbon black. 11. The pneumatic tire according to claim 9, in which the specified bead rubber has a volume resistivity of less than 1 · 10 ⁸ Ohm · cm. 12. The pneumatic tire according to claim 9, in which the specified conductive rubber of the side part has a thickness of from 0.2 to 2 mm 13. A pneumatic tire including a tread, a sidewall, a bead, a carcass extending from said tread to a specified bead through said sidewall, and a belt located on the outer side of the carcass in the radial direction of the tire, in which
tread rubber, breaker rubber and sidewall rubber, respectively formed on said tread, said breaker and said sidewall, have a volume resistivity of 10 ⁸ Ohm · cm or more,
moreover, the specified pneumatic tire further includes a continuous section of electrically conductive rubber located between the layer of the carcass forming the specified carcass and the specified rubber sidewall, and between the belt and the tread, having a thickness of from 0.2 to 3.0 mm;
conductive rubber in contact with the conductive rubber of the continuous portion and embedded in said tread such that said conductive rubber partially extends to the tread surface; and bead rubber connected to the lower end of said continuous portion of electrically conductive rubber and located in the contact region of the bead of the rim with the tire bead, where
the specified conductive rubber of the solid section, the specified conductive rubber and the specified bead rubber have a volume resistivity of less than 1 · 10 ⁸ Ohm · cm. 14. The pneumatic tire of claim 13, wherein said continuous conductive rubber comprises soot from wood resin in an amount of from 20 to 100 parts by weight. per 100 parts by weight natural rubber component.

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