tire

Abstract

The tire of the present invention comprises belt-covering rubber and carcass-covering rubber. The belt-covering rubber contains, in a specific amount, a diene-based rubber comprising natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin, and a curing agent. The dynamic storage modulus (Belt E') of the belt-covering rubber at 20°C is 13 MPa or more, and the ratio (Belt E') / (Carcass E') of the dynamic storage modulus (Belt E') of the belt-covering rubber at 20°C to the dynamic storage modulus (Carcass E') of the carcass-covering rubber at 20°C is 2.5 to 3.5.

Description

Technical Field

[0001] This invention relates to tires, and more specifically to tires that exhibit excellent durability and handling stability by suppressing the deterioration of the belt layer caused by long-term use. Background Technology

[0002] A pneumatic tire mainly consists of a pair of bead sections and sidewall sections on the left and right sides, and a tread section connecting the two sidewall sections. The carcass layer is located on the inside of the tire, and the two ends of the carcass layer are folded back from the inside of the tire to the outside, wrapping around the bead core. The carcass layer consists of at least one carcass ply, in which the carcass cords are covered by rubber.

[0003] The tread consists of a top tread and a bottom tread, with a belt layer positioned between the base of the tread and the carcass ply. The belt layer has at least one belt ply serving as a tire reinforcement layer. Because this belt ply must withstand strong impacts and heavy loads, steel cord is used as reinforcement, and the steel cord is covered with belt-coating rubber. The belt-coating rubber needs to have good adhesion to the steel cord.

[0004] On the other hand, in recent years there has been a trend of longer tire lifespans, with issues such as decreased adhesion between the steel cords and the rubber covering the belts leading to reduced durability over long-term use. Additionally, tires often require high handling stability.

[0005] Patent Document 1 disclosed a rubber composition for the purpose of providing a rubber composition with improved adhesion to steel cords. This rubber composition is a mixture of 0.3 to 1.5 parts by weight of cobalt neodecanoate borate, 0.5 to 1.0 parts by weight of cobalt stearate, 0.5 to 2.0 parts by weight of phenolic resin, 0.5 to 5.0 parts by weight of curing agent, and 4.0 to 8.0 parts by weight of sulfur in a diene rubber containing natural rubber. The composition is characterized by having a dynamic storage modulus (E′) of 13 MPa or more at 2% dynamic strain and 20°C, a loss tangent (tanδ) of 0.20 or less at 60°C, and a constant strain fatigue test at 60% strain and 400 rpm with at least 35,000 repetitions until failure.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 6288148 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The purpose of this invention is to provide a tire that suppresses the deterioration of the belt layer caused by long-term use, has excellent durability, and maintains or improves handling stability.

[0011] Methods for solving problems

[0012] The inventors conducted in-depth research and found that by specifying the composition of the belt-covering rubber and limiting the ratio of the dynamic energy storage modulus of the belt-covering rubber and the carcass-covering rubber to a specific range, the above-mentioned problems can be solved, and the present invention was completed.

[0013] That is, the present invention provides a tire, characterized in that,

[0014] It comprises a belt layer in which steel cords are covered by rubber and a carcass ply in which carcass cords are covered by rubber.

[0015] The aforementioned belt-coating rubber contains diene-based rubber including natural rubber, fillers composed of carbon black and silica, cobalt organic acid salts, phenolic resins, and curing agents.

[0016] Relative to 100 parts by weight of the diene rubber mentioned above, it contains 50-70 parts by weight of the filler mentioned above.

[0017] The mass ratio of silicon dioxide to carbon black is 1.0 to 3.5.

[0018] Relative to the aforementioned silicon dioxide, it contains 2 to 10% by mass of a silane compound represented by formula (1) below.

[0019] The dynamic energy storage modulus (Belt E') of the aforementioned belt-covering rubber at 20°C is above 13 MPa, and

[0020] The ratio of the dynamic energy storage modulus (Belt E') (MPa) of the aforementioned belt-covered rubber at 20°C to the dynamic energy storage modulus (Carcass E') (MPa) of the aforementioned carcass-covered rubber at 20°C (Belt E') / (Carcass E') is 2.5~3.5.

[0021]

[0022] (In equation (1), R) 1 and R 2 R is a hydrocarbon group with 1 to 18 carbon atoms. 3 It consists of a hydrocarbon group with 1 to 3 carbon atoms or a hydrogen atom. R 1 ~R 3 It may contain heteroatoms (but not sulfur). n represents a number from 0 to 2.

[0023] The effects of the invention

[0024] According to the present invention, a tire with excellent durability and handling stability can be provided, which suppresses the deterioration of the belt layer caused by long-term use.

[0025] The tire of the present invention specifies the composition of the belt-covering rubber as described above. This allows for long-term maintenance of the adhesion between the steel cord and the belt-covering rubber, providing excellent durability. Furthermore, by specifying the ratio (Belt E') / (Carcass E') of the dynamic energy storage modulus (MPa) of the belt-covering rubber at 20°C to the dynamic energy storage modulus (Carcass E') (MPa) of the carcass-covering rubber at 20°C as 2.5 to 3.5, excellent handling stability can also be imparted to the tire. Detailed Implementation

[0026] The present invention will now be described in further detail. First, the rubber for belt coating will be described. This rubber for belt coating contains a diene-based rubber including natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin, and a curing agent.

[0027] (Diene-based rubber)

[0028] The diene-based rubber used in the belt wrapping uses natural rubber (NR) as an essential component. From the viewpoint of improving the effectiveness of the present invention, it is preferable that the diene-based rubber contains 80 parts by mass or more of NR per 100 parts by mass. It should be noted that isoprene rubber (IR) is included in the NR described in this invention.

[0029] In addition, in this invention, diene-based rubbers can be other rubbers besides NR, such as butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), and ethylene propylene diene monomer (EPDM). These can be used alone or in combination of two or more. Furthermore, there are no particular limitations on their molecular weight or microstructure; they can be modified by end groups such as amines, amides, silyl groups, alkoxysilyl groups, carboxyl groups, and hydroxyl groups, and can also be epoxidized.

[0030] (filler)

[0031] The filler used in the belt-coating rubber is composed of carbon black and silica. From the viewpoint of improving the effectiveness of the present invention, the nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 50-120 m². 2 / g, further preferably 70~100m 2 / g. Furthermore, from the viewpoint of improving the effectiveness of the present invention, the CTAB specific surface area of ​​silica is preferably 100-180 m². 2 / g, further preferably 130~170m 2 / g. From an environmental perspective, using biomass-derived silica is also a suitable approach. It should be noted that commercially available biomass-derived silica, such as Precipitated silica K160 manufactured by FengHaiRice Biotechnology, is not substantially different in composition from silica derived from other sources.

[0032] It should be noted that in this invention, the nitrogen adsorption specific surface area (N2SA) is the value measured according to JIS K6217-2:2001 "Part 2: Methods for determining specific surface area - Nitrogen adsorption method - Single point method", and the CTAB specific surface area is the value obtained by measuring the amount of n-hexadecyltrimethylammonium bromide adsorbed onto the silica surface according to JIS K6217-3:2001 "Part 3: Methods for determining specific surface area - CTAB adsorption method".

[0033] (Organic acid cobalt salt)

[0034] Examples of cobalt organic acid salts used in belt-coating rubber include cobalt naphthenate, cobalt neodecanoate, cobalt stearate, cobalt rosinate, cobalt tert-carbonate, cobalt tallowate, cobalt neodecanoate borate, and cobalt acetylacetonate, among which cobalt organic acid salts containing boron are preferred, and cobalt neodecanoate borate is particularly preferred.

[0035] (Phenolic resin)

[0036] For rubber used in belt wrapping, a blend of phenolic resins is preferred to improve its effectiveness.

[0037] Examples of phenolic resins include cresol resins, resorcinol resins, alkylphenol resins, and modified phenolic resins. Examples of modified phenolic resins include cashew oil-modified phenolic resins, oil-modified phenolic resins, epoxy-modified phenolic resins, aniline-modified phenolic resins, and melamine-modified phenolic resins.

[0038] (Curing agent)

[0039] The curing agent preferably contains the above-mentioned phenolic resin in the belt-coating rubber.

[0040] Examples of curing agents include hexamethylenetetramine, hexamethoxymethyl melamine (HMMM), hexamethoxyhydroxymethyl melamine, pentamethoxymethyl melamine, hexaethoxymethyl melamine, paraformaldehyde polymers, and N-hydroxymethyl derivatives of melamine. These methylene donors can be used alone or in any blend.

[0041] (Silane compounds)

[0042] The belt-coating rubber contains a silane compound as shown in formula (1).

[0043]

[0044] (In equation (1), R) 1 and R 2 R is a hydrocarbon group with 1 to 18 carbon atoms. 3 It consists of a hydrocarbon group with 1 to 3 carbon atoms or a hydrogen atom. R 1 ~R 3 It may contain heteroatoms (but not sulfur). n is a number from 0 to 2.

[0045] If silica is used in the belt-coating rubber, a decrease in storage modulus E' can be observed compared to rubber without silica, under the same hardness. However, by using the silane compound shown in formula (1) above, the decrease in storage modulus E' can be compensated. In addition, if the belt-coating rubber is stored for a certain period of time before tire molding, the viscosity increases, which sometimes impairs tire moldability. However, by using this silane compound, the increase in rubber viscosity during storage can be suppressed, thereby improving tire moldability.

[0046] From the viewpoint of improving the present invention, the silane compound represented by the above formula (1) is preferably R. 1 and R 2 It is an alkyl alkylalkoxysilane compound. In this manner, n is preferably 0, R 1 Preferably, the alkyl group has 7 to 20 carbon atoms; specific examples include heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. From the viewpoint of compatibility with diene rubbers, alkyl groups with 8 to 10 carbon atoms are further preferred. Additionally, in this method, R... 3 Ethyl is particularly preferred.

[0047] (Blending ratio of rubber for belt wrapping)

[0048] The belt-coating rubber is characterized in that it contains a diene rubber including natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin and a curing agent, and contains 50 to 70 parts by mass of the filler relative to 100 parts by mass of the diene rubber, and the amount of silica relative to the amount of carbon black is 1.0 to 3.5 by mass, and contains 2 to 10 by mass of the silane compound shown in formula (1) relative to the amount of silica.

[0049] When the content of the above-mentioned filler is less than 50 parts by weight, the handling stability decreases; when it exceeds 70 parts by weight, the tire durability decreases.

[0050] When the mass ratio of silica to carbon black is less than 1.0 or more than 3.5, the durability of the tire decreases.

[0051] When the silane compound shown in formula (1) is less than 2% by mass relative to the silicon dioxide, the addition amount is too small and cannot achieve the desired effect. When it exceeds 10% by mass, the viscosity during mixing increases, scorching deteriorates, and the sulfide properties deteriorate during aging.

[0052] From the viewpoint of improving the effect of the present invention, the content of the above-mentioned filler is preferably 50 to 70 parts by mass relative to 100 parts by mass of diene rubber.

[0053] From the viewpoint of improving the effect of the present invention, the amount of silicon dioxide relative to the carbon black is preferably 1.0 to 3.3 by mass.

[0054] In addition, the carbon black content in the above-mentioned filler is preferably 30 to 50 parts by weight relative to 100 parts by weight of diene rubber, and the silica content is preferably 30 to 50 parts by weight relative to 100 parts by weight of diene rubber.

[0055] Furthermore, from the viewpoint of improving the effect of the present invention, the belt-coating rubber preferably contains, relative to 100 parts by weight of the diene rubber, 0.1 to 1.5 parts by weight of the cobalt salt of the organic acid, 0.5 to 3.0 parts by weight of the phenolic resin, and 0.5 to 5.0 parts by weight of the curing agent.

[0056] The tire of the present invention is characterized in that the dynamic energy storage modulus (BeltE') of the belt-covering rubber at 20°C is 13 MPa or more, and the ratio (BeltE') / (Carcass E') of the dynamic energy storage modulus (BeltE') (MPa) of the belt-covering rubber at 20°C to the dynamic energy storage modulus (Carcass E') (MPa) of the carcass-covering rubber at 20°C is 2.5 to 3.5.

[0057] As described above, by specifying the ratio (Belt E') / (Carcass E') of the dynamic energy storage modulus (Belt E') (MPa) of the belt-covering rubber at 20°C to the dynamic energy storage modulus (Carcass E') (MPa) of the carcass-covering rubber at 20°C as 2.5 to 3.5, the tire can be endowed with excellent handling stability.

[0058] The dynamic energy storage modulus was measured (MPa) based on JIS K6394 using an elasticity spectrometer manufactured by Toyo Seiki Co., Ltd. under the conditions of static strain 10%, dynamic strain ±2%, frequency 20Hz, and temperature 20℃.

[0059] Further optimization is to set the (Belt E') / (Carcass E') ratio to 2.7~3.3.

[0060] In addition, the dynamic energy storage modulus (Belt E') of the above-mentioned belt-covering rubber at 20°C is preferably 15~20MPa, and the dynamic energy storage modulus (Carcass E') of the above-mentioned carcass-covering rubber at 20°C is preferably 4~8MPa.

[0061] The value of dynamic energy storage modulus can be adjusted by changing the type and grade of the filler, or by changing the sulfur content.

[0062] In this invention, the composition of the rubber used for tire carcass coating is not particularly limited as long as it meets the range of (Belt E') / (Carcass E'), but it is preferable to use, for example, diene-based rubbers such as NR, BR, and SBR, and to use 30 to 50 parts by weight of carbon black relative to 100 parts by weight of diene-based rubber. The nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 70 to 100 m². 2 / g.

[0063] It should be noted that, in addition to the components mentioned above, the belt-coating rubber and carcass-coating rubber may also be blended with vulcanizing agents or crosslinking agents; vulcanization accelerators or crosslinking accelerators; antioxidants; plasticizers; and various additives commonly blended in belt-coating rubber or carcass-coating rubber compositions. These additives can be compounded and formulated into compositions using conventional methods for vulcanization or crosslinking. The blending amounts of these additives can also be the conventional blending amounts, provided they do not violate the purpose of this invention.

[0064] The tire of this invention suppresses the deterioration of the belt layer caused by long-term use, exhibiting excellent durability and handling stability. Furthermore, the tire of this invention is preferably a pneumatic tire, which can be filled with inert gases such as air and nitrogen, as well as other gases.

[0065] Example

[0066] The present invention is further illustrated below by way of examples and comparative examples, but the present invention is not limited to the examples below.

[0067] Standard Example 1, Examples 1-5 and Comparative Examples 1-6

[0068] Sample modulation

[0069] In the mixtures (parts by weight) shown in Table 1, all components except the vulcanizing agents (vulcanization accelerator, sulfur) were mixed for 5 minutes at 80°C in a Banbury internal mixer. The temperature reached at this point was 150°C. Next, the vulcanizing agents were added using rollers and mixed to obtain rubber compositions. The resulting rubber compositions (unvulcanized) were then vulcanized under pressure at 170°C for 10 minutes in a mold (15cm × 15cm × 0.2cm) to produce vulcanized rubber test pieces, which were then evaluated as follows.

[0070] Dynamic storage modulus (E'): Using the obtained test piece, the dynamic storage modulus (MPa) was measured using an elasticity spectrometer manufactured by Toyo Seiki Co., Ltd. based on JIS K6394 at a static strain of 10%, a dynamic strain of ±2%, a frequency of 20 Hz, and a temperature of 20 °C.

[0071] Constant strain fatigue test: Using the obtained test piece, dumbbell JIS No. 3 test piece was made based on JIS K6251. With JIS K6270 as a reference, tensile constant strain fatigue test was carried out under the conditions of 20℃, strain 100%, test frequency 6.67Hz (400 rpm), and the number of repetitions until failure was determined.

[0072] Tire handling stability: The obtained rubber composition was used in the belt wrapping rubber and the carcass wrapping rubber to produce test tires. Each test tire was assembled onto a wheel with a rim size of 18×8.5J and mounted on a test vehicle. Sensory evaluation was conducted by the test driver under an air pressure of 240 kPa in a test track formed by a paved road. The results are expressed as an index with the measured value of Standard Example 1 as 100. A higher index value indicates better handling stability.

[0073] Tire durability:

[0074] The resulting rubber composition was used for belt wrapping and carcass wrapping rubber to vulcanize pneumatic tires (size 295 / 35R21). The resulting tires were mounted on rims (21×10.5J), filled with 100% oxygen at an air pressure of 350 kPa, and left to stand for 14 days at 70°C. Then, the air pressure was adjusted to 170 kPa, and the tires were placed in an indoor drum testing machine (1707 mm diameter, JIS D4230-based) for 6,000 km of driving test at 60 km / h, increasing the load by 13% every 2 hours starting at 88% of the JATMA-specified load. After the driving test, the tires were removed, and the amount of edge separation (mm) in the belt layers was measured.

[0075] The results are shown in Table 1.

[0076] [Table 1]

[0077]

[0078] *1: NR(TSR20)

[0079] *2: BR( Nipol BR1220 manufactured by Co., Ltd.)

[0080] *3: SBR( Nipol 1502 manufactured by Co., Ltd.)

[0081] *4: Carbon black 1 ( Made by Co., Ltd. Nitrogen adsorption specific surface area (N2SA) = 27 m² 2 / g)

[0082] *5: Carbon black 2 ( Made by Co., Ltd. 300. Nitrogen adsorption specific surface area (N2SA) = 84 m² 2 / g)

[0083] *6: Silica (Precipitated silica K160, manufactured by Feng Hai Rice Biotechnology Co., Ltd., CTAB specific surface area = 158m²) 2 / g)

[0084] *7: Silane coupling agent ( Company Si75)

[0085] *8: Silane compounds (Shin-Etsu Chemical Co., Ltd. KBE-3083, Octyltriethoxysilane)

[0086] *9: Zinc oxide (three types of zinc oxide manufactured by Zhengtong Chemical Industry Co., Ltd.)

[0087] *10: Anti-aging agents ( SANTOFLEX 6PPD (Company)

[0088] *11: Cobalt neodecanoate borate (NBC-2 prepared by DIC CORPORATION, cobalt content = 22.2% by mass, expressed as cobalt organic acid in Table 1.)

[0089] *12: Phenolic resins (PENACOLITE RESIN B-18-S and resorcinol resin manufactured by INDSPEC)

[0090] *13: Hardener (CYREZ964RPC, HMM, manufactured by CYTEC INDUSTRIES)

[0091] *14: Sulfur (manufactured by Shikoku Chemical Industry Co., Ltd.) OT-20)

[0092] *15: Vulcanization accelerator CZ (manufactured by Ouchi Shinsei Chemical Co., Ltd.) CZ-G)

[0093] *16: Vulcanization accelerator DZ (manufactured by Ouchi Shinsei Chemical Co., Ltd.) DZ)

[0094] As can be seen from the results in Table 1, each embodiment has a belt layer with steel cords covered by belt-wrapped rubber and a carcass ply layer with carcass cords covered by carcass-wrapped rubber. The belt-wrapped rubber contains a diene rubber including natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin, and a curing agent. Relative to 100 parts by mass of the diene rubber, it contains 50 to 70 parts by mass of the filler. The amount of silica relative to the carbon black is 1.0 to 3.5 by mass (silica / carbon black ratio). Relative to the silica, it contains 2 to 10% by mass of the silane compound shown in formula (1). The dynamic storage modulus (Belt E') at 20°C is 13 MPa or more. Furthermore, the ratio of the dynamic storage modulus (Belt E') (MPa) of the belt-wrapped rubber at 20°C to the dynamic storage modulus (Carcass E') (MPa) of the carcass-wrapped rubber at 20°C is (Belt E') With an E') / (Carcass E') ratio of 2.5 to 3.5, a tire with superior durability and handling stability compared to the rubber composition of Standard Example 1 can be provided, which suppresses the deterioration of the belt layer caused by long-term use.

[0095] On the other hand, Comparative Example 1 resulted in poor tire durability because the content of the filler exceeded the upper limit specified in this invention and the silica / carbon black ratio exceeded the upper limit specified in this invention.

[0096] Comparative Example 2 resulted in poor tire handling stability because the content of the filler was less than the lower limit specified in this invention and (Belt E') / (Carcass E') was also less than the lower limit specified in this invention.

[0097] Comparative Example 3 resulted in poor tire durability because the silica / carbon black ratio was less than the lower limit specified in this invention.

[0098] Comparative Example 4 results in poor tire handling stability because the dynamic energy storage modulus (Belt E') of the belt-covered rubber at 20°C is less than the lower limit specified in this invention, and (Belt E') / (Carcass E') is also less than the lower limit specified in this invention.

[0099] Comparative Example 5 resulted in poor tire handling stability because it did not contain phenolic resin and curing agent, the dynamic storage modulus (Belt E') was less than the lower limit specified in this invention, and the ratio of (Belt E') to (Carcass E') was also less than the lower limit specified in this invention.

[0100] Comparative Example 6 results in poor tire handling stability because the dynamic energy storage modulus (Belt E') of the belt-covered rubber at 20°C is less than the lower limit specified in this invention, and (Belt E') / (Carcass E') is also less than the lower limit specified in this invention.

[0101] The present invention includes the following embodiments.

[0102] Implementation method 1:

[0103] A tire, characterized in that,

[0104] It comprises a belt layer in which steel cords are covered by rubber and a carcass ply in which carcass cords are covered by rubber.

[0105] The aforementioned belt-coating rubber contains: a diene-based rubber including natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin, and a curing agent.

[0106] Relative to 100 parts by weight of the diene rubber mentioned above, it contains 50-70 parts by weight of the filler mentioned above.

[0107] The mass ratio of silicon dioxide to carbon black is 1.0 to 3.5.

[0108] Relative to the aforementioned silicon dioxide, it contains 2 to 10% by mass of a silane compound represented by formula (1) below.

[0109] The dynamic energy storage modulus (Belt E') of the aforementioned belt-covering rubber at 20°C is above 13 MPa, and

[0110] The ratio of the dynamic energy storage modulus (Belt E') (MPa) of the aforementioned belt-covered rubber at 20°C to the dynamic energy storage modulus (Carcass E') (MPa) of the aforementioned carcass-covered rubber at 20°C (Belt E') / (Carcass E') is 2.5~3.5.

[0111]

[0112] (In equation (1), R) 1 and R 2 R is a hydrocarbon group with 1 to 18 carbon atoms. 3It consists of a hydrocarbon group with 1 to 3 carbon atoms or a hydrogen atom. R 1 ~R 3 It may contain heteroatoms (but not sulfur). n represents a number from 0 to 2.

[0113] Implementation Method 2:

[0114] The tire rubber composition according to Embodiment 1 is characterized in that the nitrogen adsorption specific surface area (N2SA) of the carbon black is 50-120 m². 2 / g, and the CTAB specific surface area of ​​the above-mentioned silica is 100~170m². 2 / g.

[0115] Implementation Method 3:

[0116] The tire according to embodiment 1 or 2 is characterized in that the nitrogen adsorption specific surface area (N2SA) of the carbon black is 70~100m². 2 / g, and the CTAB specific surface area of ​​the above-mentioned silica is 130~170m². 2 / g.

[0117] Implementation Method 4:

[0118] The tire rubber composition according to any one of Embodiments 1 to 3 is characterized in that the silica is derived from biomass.

[0119] Implementation Method 5:

[0120] The tire according to any one of embodiments 1 to 4 is characterized in that, in the belt-coating rubber, relative to 100 parts by weight of the diene rubber, it contains 0.3 to 1.5 parts by weight of the cobalt organic acid salt, 0.5 to 3.0 parts by weight of the phenolic resin, and 0.5 to 5.0 parts by weight of the curing agent.

[0121] Implementation method 6:

[0122] The tire according to any one of embodiments 1 to 5 is characterized in that the above-mentioned organic cobalt salt is cobalt borate neodecanoate.

[0123] Implementation Method 7:

[0124] The tire according to any one of embodiments 1 to 6 is characterized in that, in 100 parts by mass of the diene rubber, the proportion of natural rubber is 80 parts by mass or more.

[0125] Implementation Method 8:

[0126] The tire according to any one of embodiments 1 to 7 is characterized in that the above (Belt E') / (Carcass E') is 2.7 to 3.3.

[0127] Implementation Method 9:

[0128] The tire according to any one of embodiments 1 to 8 is characterized in that, in the silane compound represented by formula (1) above, n is 0, R 1 It is an alkyl group with 7 to 20 carbon atoms, R 3 It is an ethyl group.

Claims

1. A tire, characterized in that, It comprises a belt layer in which steel cords are covered by rubber and a carcass ply in which carcass cords are covered by rubber. The belt-coating rubber comprises: a diene rubber including natural rubber, a filler composed of carbon black and silica, an organic cobalt salt, a phenolic resin, and a curing agent. Relative to 100 parts by weight of the diene rubber, it contains 50-70 parts by weight of the filler. The amount of silica relative to the carbon black is 1.0-3.5 by weight. Relative to the silica, it contains 2-10% by weight of a silane compound represented by formula (1). The dynamic energy storage modulus of the rubber used for belt covering at 20°C is Belt E', which is above 13 MPa and below 20 MPa. The ratio of the dynamic energy storage modulus of the belt-covering rubber at 20°C (Belt E') to the dynamic energy storage modulus of the carcass-covering rubber at 20°C (Carcass E') is 2.5~3.5, where the units of Belt E' and Carcass E' are both MPa. In equation (1), R 1 and R 2 R is a hydrocarbon group with 1 to 18 carbon atoms. 3 R is a hydrocarbon group with 1 to 3 carbon atoms or a hydrogen atom. 1 ~R 3 It may contain heteroatoms, but not sulfur, where n represents a number from 0 to 2.

2. The tire according to claim 1, characterized in that, The nitrogen adsorption specific surface area (N2SA) of the carbon black is 50~120 m². 2 / g, and the CTAB specific surface area of ​​the silica is 100~170m². 2 / g.

3. The tire according to claim 1, characterized in that, The silica is derived from biomass.

4. The tire according to claim 1, characterized in that, The belt-coating rubber contains, relative to 100 parts by weight of the diene rubber, 0.1 to 1.5 parts by weight of the cobalt organic acid salt, 0.5 to 3.0 parts by weight of the phenolic resin, and 0.5 to 5.0 parts by weight of the curing agent.

5. The tire according to claim 1, characterized in that, The organic acid cobalt salt is cobalt borate neodecanoate.

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