JP4509148B2 - Rubber composition for covering carcass cord, carcass, tire and tire manufacturing method - Google Patents

Description

  The present invention relates to a rubber composition for covering a carcass cord, a carcass, a tire, and a method for manufacturing a tire, and in particular, the amount of a material derived from petroleum resources can be reduced, and the rolling resistance of the tire and the durability of the tire The present invention relates to a rubber composition for covering a carcass cord, a carcass and a tire manufactured using the rubber composition for covering a carcass cord, and a method for manufacturing the tire.

  In general, for example, in a tire for a passenger car, it is necessary to reduce the rolling resistance of the tire in consideration of environmental problems and economy. In addition, the durability of tires during long-term travel of passenger cars is also required.

In such passenger car tires, for example, steel cords and organic fiber cords are generally used as reinforcing materials, and organic fiber cords are often used for the carcass cords constituting the tire carcass. When an organic fiber cord is used for the carcass cord, the carcass cord is widely coated with a rubber composition for covering the carcass cord in order to improve the adhesion between the carcass cord and the rubber composition covering the carcass cord. (See, for example, Patent Document 1).
JP 2006-328194 A

In recent years, environmental issues have become more important, and regulations on CO ₂ emission suppression have been strengthened. In addition, since petroleum resources are limited and the supply amount is decreasing year by year, oil prices are expected to rise in the future, and the use of materials consisting of petroleum resources such as synthetic rubber and carbon black is not recommended. There is a limit. Therefore, assuming that oil will be depleted in the future, the use of materials derived from petroleum resources such as rubber components such as natural rubber and white fillers such as silica and calcium carbonate will be used. The amount needs to be reduced.

  However, even when tires are made by reducing the amount of materials derived from petroleum resources, they have the same or better characteristics than when tires are made using a large amount of materials derived from conventional petroleum resources. Need to be.

  Accordingly, an object of the present invention is to provide a rubber composition for covering a carcass cord that can reduce the amount of a material derived from petroleum resources and can have excellent tire rolling resistance and tire durability. Another object of the present invention is to provide a carcass and tire manufactured using the rubber composition for covering a carcass cord, and a method for manufacturing the tire.

The present invention includes a natural rubber, a natural rubber 100 parts by weight with respect to 60 parts by mass or more and 80 parts by weight of silica, and 15 parts by weight or less of the silane coupling agent 1 part by mass or more with respect to natural rubber 100 parts by weight A rubber composition for covering a carcass cord, comprising 1 to 10 parts by mass of calcium stearate with respect to 100 parts by mass of natural rubber.

In the rubber composition for coating a carcass cord of the present invention, the specific surface area of nitrogen adsorption by silica BET method is preferably 70 m ² / g or more and 250 m ² / g or less.

  In addition, the present invention is a carcass comprising a carcass cord and any one of the carcass cord covering rubber compositions described above, wherein the carcass cord is embedded in the carcass cord covering rubber composition.

Moreover, this invention is a tire manufactured using said carcass.
Furthermore, the present invention is a method for manufacturing the tire described above, and is a method for manufacturing a tire including a step of embedding a carcass cord in a rubber composition for covering a carcass cord.

  According to the present invention, a rubber composition for covering a carcass cord, which can reduce the amount of a material derived from petroleum resources and can be excellent in tire rolling resistance and tire durability, A carcass and tire manufactured using the rubber composition for covering a carcass cord, and a method for manufacturing the tire can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

<Diene rubber>
As the diene rubber used in the present invention, conventionally known diene rubbers can be used. From the viewpoint of reducing the amount of materials derived from petroleum resources, natural rubber (NR) or epoxidized natural rubber can be used. It is preferable to use any one of rubber (ENR) alone or in combination of natural rubber (NR) and epoxidized natural rubber (ENR).

  Here, as the natural rubber (NR), a conventionally known rubber can be used, and for example, TSR20, RSS # 3 and the like generally used in the rubber industry can be used. In addition, as the epoxidized natural rubber (ENR), a conventionally known epoxidized natural rubber can be used, and for example, a commercially available epoxidized natural rubber or an epoxidized natural rubber can be used.

<Silica>
The rubber composition for covering a carcass cord of the present invention contains 60 parts by mass or more and 80 parts by mass or less of silica with respect to 100 parts by mass of the diene rubber. When the content of silica is less than 60 parts by mass with respect to 100 parts by mass of the diene rubber, the amount of the material derived from petroleum resources cannot be suppressed, and when it exceeds 80 parts by mass The rolling resistance of a tire produced using the rubber composition for covering a carcass cord of the present invention is deteriorated. Here, conventionally known silica can be used as the silica used in the present invention. For example, anhydrous silica and / or hydrous silica can be used.

  Further, from the viewpoint of suppressing shrinkage, the content of silica is preferably 60 parts by mass or more and more preferably 65 parts by mass or more with respect to 100 parts by mass of the diene rubber.

  Moreover, from a viewpoint which does not raise Mooney viscosity, it is preferable that it is 80 mass parts or less with respect to 100 mass parts of said diene rubbers, and it is more preferable that it is 75 mass parts or less.

Further, the nitrogen adsorption specific surface area (hereinafter referred to as “BET specific surface area”) of silica by the BET method is preferably 70 m ² / g or more, and more preferably 80 m ² / g or more. When the BET specific surface area of silica is 70 m ² / g or more, particularly 80 m ² / g or more, the reinforcing effect by silica tends to be more sufficiently obtained.

It is preferable that the BET specific surface area of silica is less than 250 meters ² / g, more preferably at most 240 m ² / g. When the BET specific surface area of silica is 250 m ² / g or less, particularly 240 m ² / g or less, an increase in Mooney viscosity of the rubber composition for coating a carcass cord of the present invention due to the blending of silica can be suppressed. The processability when the carcass cord covering rubber composition of the invention is topped on the carcass cord tends to be good.

  In addition, the BET specific surface area of a silica can be measured by the method based on ASTM-D-4820-93.

<Silane coupling agent>
The rubber composition for covering a carcass cord of the present invention contains 1 to 15 parts by mass of a silane coupling agent with respect to 100 parts by mass of the diene rubber. When the content of the silane coupling agent is less than 1 part by mass with respect to 100 parts by mass of the diene rubber, the rubber strength after vulcanization is lowered and the durability of the tire is deteriorated. When exceeding, the rubber | gum strength after vulcanization will become high too much, and the rolling resistance of a tire will fall.

  Here, conventionally known silane coupling agents can be used, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3 -Trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-tri Ethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoylte Rasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3 -Sulfide systems such as triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, Mercapto series such as 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane Vinyl-based, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, etc. Glycidoxy series such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3 -Nitropropyl trimethoxysilane, 3-nitropropyl triethoxysilane and other nitro compounds, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane Chloro such as And the like. In addition, said silane coupling agent may be used independently and may be used in combination of 2 or more type.

  Moreover, it is preferable that it is 1 mass part or more with respect to 100 mass parts of said diene rubbers, and, as for content of a silane coupling agent, it is more preferable that it is 2 mass parts or more. When the content of the silane coupling agent is less than 1 part by mass with respect to 100 parts by mass of the diene rubber, the effect tends to be hardly obtained.

  Moreover, it is preferable that it is 15 mass parts or less with respect to 100 mass parts of said diene rubbers, and, as for content of a silane coupling agent, it is more preferable that it is 14 mass parts or less. When the content of the silane coupling agent exceeds 15 parts by mass with respect to 100 parts by mass of the silica, the effect tends to be small for a high cost.

<Calcium stearate>
The rubber composition for coating a carcass cord of the present invention contains 1 to 10 parts by mass of calcium stearate with respect to 100 parts by mass of the diene rubber. When the content of calcium stearate is 1 part by mass or more and 10 parts by mass or less based on 100 parts by mass of the diene rubber, the processability of the rubber composition for covering a carcass cord of the present invention is improved. In addition, the rubber strength after vulcanization can be excellent. Here, a conventionally well-known thing can be used as a calcium stearate, for example, a calcium stearate etc. by Nippon Oil & Fat Co., Ltd. can be used.

  The content of calcium stearate is preferably 1 part by mass or more and more preferably 2 parts by mass or more with respect to 100 parts by mass of the diene rubber. When the content of calcium stearate is less than 1 part by mass with respect to 100 parts by mass of the diene rubber, the effect tends not to be obtained.

  Furthermore, the content of calcium stearate is preferably 10 parts by mass or less and more preferably 9 parts by mass or less with respect to 100 parts by mass of the diene rubber. When the content of calcium stearate is more than 10 parts by mass relative to 100 parts by mass of the diene rubber, the balance tends to be poor in terms of rolling resistance and rubber strength.

<Carbon black>
The rubber composition for covering a carcass cord of the present invention may contain a conventionally known carbon black derived from petroleum resources, but from the viewpoint of reducing the amount of materials derived from petroleum resources, The content of carbon black is preferably 25 parts by mass or less, more preferably 5 parts by mass or less, and most preferably not contained at all with respect to 100 parts by mass of the diene rubber.

  Moreover, as carbon black, conventionally well-known carbon black, such as SAF, ISAF, HAF, and FEF, can be used, for example.

<Other ingredients>
In addition to the above materials, the rubber composition for covering a carcass cord of the present invention includes various materials such as oil, stearic acid, zinc oxide, sulfur, and vulcanization accelerators that are generally used in the tire industry. May be appropriately blended.

  As oil, a conventionally well-known thing can be used, for example, process oil, vegetable oil, or a mixture thereof etc. can be used. As the process oil, for example, paraffinic process oil, naphthenic process oil, aromatic process oil, or the like can be used. As vegetable oils and fats, for example, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice bran oil, beet flower oil, Sesame oil, olive oil, sunflower oil, palm kernel oil, coconut oil, jojoba oil, macadamia nut oil, safflower oil, tung oil, and the like can be used.

  A conventionally well-known thing can be used as a stearic acid, for example, the stearic acid by Nippon Oil & Fat Co., Ltd. can be used.

  As the zinc oxide, conventionally known ones can be used, and for example, Zinc Hana No. 1 manufactured by Mitsui Metal Mining Co., Ltd. can be used.

  Conventionally known sulfur can be used as the sulfur, for example, Kristex HSOT20 manufactured by Flexis, Sanfel EX manufactured by Sanshin Chemical Industry Co., Ltd., or the like.

  As the vulcanization accelerator, conventionally known ones can be used. For example, sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine or aldehyde-ammonia Further, those containing at least one of imidazoline-based or xanthate-based vulcanization accelerators can be used. Examples of the sulfenamide system include CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N, N-dicyclohexyl-2- Sulfenamide compounds such as benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide, and the like can be used. Examples of the thiazole type include MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt of 2-mercaptobenzothiazole, zinc salt, copper salt, cyclohexylamine salt, 2- (2,4-dinitro). Thiazole compounds such as phenyl) mercaptobenzothiazole and 2- (2,6-diethyl-4-morpholinothio) benzothiazole can be used. Examples of thiurams include TMTD (tetramethylthiuram disulfide), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylenethiuram tetrasulfide, dipentamethylenethiuram hexasulfide. Further, thiuram compounds such as tetrabutylthiuram disulfide and pentamethylenethiuram tetrasulfide can be used. As the thiourea series, for example, thiourea compounds such as thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diortolylthiourea and the like can be used. Examples of guanidine-based compounds include guanidine-based compounds such as diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, and diphenylguanidine phthalate. Examples of dithiocarbamate include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate , Complex salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecyl (or octadecyl) isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, diamyl Dithiocarbamate such as cadmium It can be used carbamic acid compounds. As the aldehyde-amine system or aldehyde-ammonia system, for example, an aldehyde-amine system such as an acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, an acetaldehyde-ammonia reaction product, or an aldehyde-ammonia system compound is used. be able to. As the imidazoline-based compound, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. As the xanthate type, for example, a xanthate type compound such as zinc dibutylxanthate can be used. These vulcanization accelerators may be used alone or in combination of two or more.

<Rubber composition for carcass cord coating>
The rubber composition for covering a carcass cord of the present invention is obtained by, for example, kneading the above material using a conventionally known open roll, Banbury mixer, pressure kneader, continuous kneader or the like. Can be obtained by mixing.

<Carcass>
FIG. 1 shows a schematic perspective view of an example of a part of a carcass produced using the rubber composition for covering a carcass cord of the present invention. Here, the carcass 4 has a structure in which a plurality of carcass cords 11 are embedded in a sheet-like rubber composition 15 for covering a carcass cord of the present invention.

  The carcass 4 produced by using the rubber composition for covering a carcass cord of the present invention is, for example, an unvulcanized carcass cord above and below the carcass cord 11 with a plurality of carcass cords 11 stretched and arranged in parallel. It can be produced by topping the coating rubber composition 15.

  In the present invention, as the carcass cord 11, a conventionally known one can be used, and for example, a filament made of organic fiber or steel can be used.

<Tire>
Hereinafter, an example of a method for manufacturing a tire using a carcass manufactured using the rubber composition for covering a carcass cord of the present invention will be described.

  First, the carcass produced as described above is wound in an annular shape on the outer peripheral surface of a conventionally known drum roll.

  Here, for example, the carcass is formed by topping the upper and lower surfaces of a plurality of carcass cords made of a filament such as polyester, and the plurality of carcass cords are covered with the rubber composition for covering a carcass cord of the present invention. It can be produced by embedding in an object.

  Next, as shown in the schematic cross-sectional view of FIG. 2, a bead wire 5 in which a plurality of wires are bundled into an annular shape is driven onto the outer peripheral surfaces of both ends of the annular carcass 4 and a bead apex 7 is installed. Then, both ends of the carcass 4 are folded inward, and the bead wire 5 and the bead apex 7 are wrapped between the folded portion 4 a and the non-folded portion 4 b of the carcass 4.

  Subsequently, as shown in the schematic cross-sectional view of FIG. 3, the carcass 4 in which the bead wire 5 and the bead apex 7 are wrapped at the ends is inflated in a toroidal shape. Then, the belt 6 is formed by laminating the first belt 6b and the second belt 6a in this order on the central outer peripheral surface of the carcass 4.

  After that, a green tire is produced by a conventionally known method, and the produced green tire is placed in a tire molding die and then vulcanized to obtain a green tire tread, sidewall, belt, jointless band, inner An unvulcanized rubber composition constituting each part such as a liner, a carcass, and a bead apex is vulcanized to produce a tire.

  In addition, in the above, description about the process of installing a tread, a sidewall, a jointless band, an inner liner, etc. is omitted.

  FIG. 4 shows a schematic cross-sectional view of the upper part of an example of the tire manufactured as described above. FIG. 5 is a schematic diagram for illustrating the internal structure of another example of a tire manufactured using a carcass manufactured using the rubber composition for covering a carcass cord of the present invention.

  Here, as shown in FIGS. 4 and 5, in the tire manufactured as described above, the sidewall 9 is formed on the side surface of the carcass 4 in which the bead wire 5 and the bead apex 7 are wrapped at both ends thereof. ing.

  A belt 6 in which a first belt layer 6b and a second belt layer 6a are laminated in this order is installed at the center of the outer peripheral surface of the carcass 4 and covers the end of the belt 6. A jointless band 1 is installed, and a tread 8 serving as a ground contact portion of the tire is formed on the outer peripheral surface side of the belt 6 and the jointless band 1. In addition, an inner liner 10 is provided on the inner peripheral surface of the carcass 4 in order to prevent gas such as air inside the carcass 4 from leaking to the outside.

  Since the tire having the above configuration is manufactured using a carcass manufactured using the rubber composition for covering a carcass cord of the present invention, the tire has excellent rolling resistance and tire durability. be able to.

  Furthermore, since the tire having the above-described configuration can suppress the amount of materials derived from petroleum resources, it can be an eco-tire that is environmentally friendly and can be prepared for a reduction in the future supply of oil. .

  Needless to say, from the viewpoint of reducing the amount of the material derived from the petroleum resource, it is preferable to use the material other than the material derived from the petroleum resource as much as possible for the tire portion other than the carcass.

  Moreover, in the above, although the tire for passenger cars is illustrated, this invention is not limited to this, It is set as the tire used for various vehicles, such as for passenger cars, trucks, buses, and heavy vehicles. it can.

<Preparation of unvulcanized rubber composition>
First, in accordance with the formulation shown in Table 1, materials other than sulfur and a vulcanization accelerator were supplied to a closed mixer and kneaded at 150 ° C. for 3 minutes. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded material, and then kneaded at 90 ° C. for 3 minutes to obtain the unvulcanized rubber compositions of Examples 1-2 and Comparative Examples 1-3, respectively. It was.

  In addition, the numerical value described in the column of the other material of Table 1 represents the blending amount of each material in parts by mass when the blending amount of the diene rubber is 100 parts by mass.

(Note 1) Diene rubber A: SBR1502 manufactured by JSR Corporation
(Note 2) Diene rubber B: TSR20 grade natural rubber (NR)
(Note 3) Carbon black: N339 manufactured by Mitsubishi Chemical Corporation
(Note 4) Silica: Z115GR manufactured by Rhodia (BET specific surface area: 112 m ² / g)
(Note 5) Process oil: Diana Process PS32 manufactured by Idemitsu Kosan Co., Ltd.
(Note 6) Stearic acid: Paulownia made by NOF Corporation (Note 7) Calcium stearate: GF200 made by NOF Corporation
(Note 8) Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. (Note 9) Silane coupling agent: Si75 manufactured by Degussa
(Note 10) Sulfur: Kristex HSOT20 manufactured by Flexis
(Note 11) Vulcanization accelerator: NOXELLER NS manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
<Production of carcass>
Each of the unvulcanized rubber compositions of Examples 1-2 and Comparative Examples 1-3 produced as described above was processed into a thin film of 1 mm or less using a calender roll, and processed into a film. The following carcass cords were coated with the obtained unvulcanized rubber compositions, and Examples 1 to 2 and Comparative Examples 1 to 2 were obtained from the unvulcanized rubber compositions of Examples 1 to 2 and Comparative Examples 1 to 3, respectively. Each carcass of 3 was produced.

  In the carcasses of Examples 1 and 2 and Comparative Examples 1 to 3, conditions other than the unvulcanized rubber composition are the same. Further, when the Mooney viscosity of the unvulcanized rubber composition increases, the heat generation of the unvulcanized rubber composition during processing may increase, so the line speed was adjusted as appropriate so as to suppress the increase in Mooney viscosity.

<Rolling resistance measurement>
Using the carcass of Examples 1-2 and Comparative Examples 1-3 produced as described above, passenger car tires of Examples 1-2 and Comparative Examples 1-3 of 195 / 65R15 size were produced. . In addition, in the passenger car tires of Examples 1-2 and Comparative Examples 1-3, the conditions other than the carcass are the same.

Here, the basic structure of the produced passenger car tire is as follows.
Carcass cord angle 90 degrees in the tire circumferential direction Cord material Rayon 1840dtex / 2
Belt cord angle 24 degrees × 26 degrees in the tire circumferential direction Cord material Steel (brass plating (copper-zinc alloy plating))
Jointless band Cord angle 0 degrees in the tire circumferential direction Cord material Steel cord 3 × 3 × 0.17
And each passenger car tire of Examples 1-2 and Comparative Examples 1-3 produced as described above is mounted on a regular rim (6JJ × 15), and a rolling resistance tester manufactured by STL is used. The rolling resistance was measured for each of the passenger car tires of Examples 1-2 and Comparative Examples 1-3 under the conditions of an internal pressure of 230 kPa, a speed of 80 km / h, and a load of 49 N.

  Then, for each of the passenger car tires of Examples 1 and 2 and Comparative Examples 1 to 3, a rolling resistance coefficient (RRC) obtained by dividing the measured value of rolling resistance by the load was calculated, and the rolling resistance coefficient of the passenger car tire of Comparative Example 1 was calculated. The relative value was calculated when (RRC) was set to 100. The results are shown in Table 1. It shows that rolling resistance is so small that the numerical value of the column of rolling resistance of Table 1 is small, and the performance of a tire is favorable.

<Rubber strength>
Vulcanization of each of Examples 1-2 and Comparative Examples 1-3 by vulcanizing each of the unvulcanized rubber compositions of Examples 1-2 and Comparative Examples 1-3 at 170 ° C. for 10 minutes. A rubber sheet was obtained.

  Then, the vulcanized rubber sheet obtained as described above was subjected to a tensile test using a dumbbell-shaped No. 3 test piece according to JIS K6251, and the modulus at break (TB) and the elongation at break ( EB) was determined. And as a parameter | index of the rubber strength of each vulcanized rubber sheet of Examples 1-2 and Comparative Examples 1-3, the product of the modulus at break (TB) and the elongation at break (EB) was calculated. The results are shown in Table 1.

  In the column of rubber strength in Table 1, the larger the value, the higher the rubber strength. In calculating the product of the modulus at break (TB) and the elongation at break (EB), the unit of modulus at break (TB) is MPa, and the unit of elongation at break (EB) is%. It is.

<Evaluation>
As shown in Table 1, when each of the unvulcanized rubber compositions of Examples 1 and 2 containing 1 to 10 parts by mass of calcium stearate with respect to 100 parts by mass of natural rubber (NR), Even when silica is blended in a large amount of 60 parts by mass with respect to 100 parts by mass of natural rubber (NR), the unvulcanized rubber composition or natural rubber of Comparative Examples 1 and 2 that does not contain calcium stearate (NR) ) The rolling resistance of the passenger car tire is reduced and the rubber after vulcanization is compared with the case where the unvulcanized rubber composition of Comparative Example 3 containing 15 parts by mass of calcium stearate with respect to 100 parts by mass is used. Since the strength is excellent, the durability of the tire is considered to be excellent.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, a rubber composition for covering a carcass cord, which can reduce the amount of a material derived from petroleum resources and can be excellent in tire rolling resistance and tire durability, A carcass and tire manufactured using the rubber composition for covering a carcass cord, and a method for manufacturing the tire can be provided.

It is a typical perspective view of an example of a part of carcass produced using the rubber composition for covering a carcass cord of the present invention. It is typical sectional drawing for demonstrating a part of manufacturing process of an example of the method of manufacturing a tire using the belt produced using the rubber composition for carcass cord coating of this invention. It is typical sectional drawing for demonstrating another part of manufacturing process of an example of the method of manufacturing a tire using the belt produced using the rubber composition for carcass cord coating of this invention. It is typical sectional drawing of the upper part of an example of the tire produced using the carcass produced using the rubber composition for carcass cord coating of this invention. It is a schematic diagram for illustrating the internal structure of another example of a tire manufactured using a carcass manufactured using the rubber composition for covering a carcass cord of the present invention.

Explanation of symbols

  1 jointless band, 4 carcass, 4a folded portion, 4b unfolded portion, 5 bead wire, 6 belt, 6a second belt, 6b first belt, 7 bead apex, 8 tread, 9 sidewall, 10 inner liner 11 Carcass cord, 15 Rubber composition for carcass cord coating.

Claims (5)

Natural rubber, 80 mass parts or less of silica 60 parts by mass or more with respect to the natural rubber 100 parts by weight, said natural rubber 100 parts by weight with respect to 1 part by weight to 15 parts by weight of a silane coupling agent, wherein A rubber composition for covering a carcass cord, comprising 1 to 10 parts by mass of calcium stearate with respect to 100 parts by mass of natural . The rubber composition for covering a carcass cord according to claim 1, wherein the silica has a nitrogen adsorption specific surface area by BET method of 70 m ² / g or more and 250 m ² / g or less. A carcass cord, comprises a rubber composition for covering a carcass cord according to claim 1 or 2, wherein the carcass cord is formed by being embedded in the rubber composition for covering a carcass cord, the carcass. A tire manufactured using the carcass according to claim 3 . 5. A method for manufacturing a tire according to claim 4 , comprising a step of embedding the carcass cord in the rubber composition for covering a carcass cord.

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