WO2018194063A1 - Rubber composition for inner-layer member of tire, and heavy-duty pneumatic tire obtained using same - Google Patents

Rubber composition for inner-layer member of tire, and heavy-duty pneumatic tire obtained using same Download PDF

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Publication number
WO2018194063A1
WO2018194063A1 PCT/JP2018/015886 JP2018015886W WO2018194063A1 WO 2018194063 A1 WO2018194063 A1 WO 2018194063A1 JP 2018015886 W JP2018015886 W JP 2018015886W WO 2018194063 A1 WO2018194063 A1 WO 2018194063A1
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Prior art keywords
rubber composition
tire
rubber
layer member
mass
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PCT/JP2018/015886
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French (fr)
Japanese (ja)
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昇 齋藤
崇浩 齊藤
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株式会社ブリヂストン
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/22—Compounds containing nitrogen bound to another nitrogen atom
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
    • C08K5/39—Thiocarbamic acids; Derivatives thereof, e.g. dithiocarbamates
    • C08K5/40—Thiurams, i.e. compounds containing groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L21/00—Compositions of unspecified rubbers

Definitions

  • the present invention relates to a rubber composition for an inner layer member of a tire and a heavy duty pneumatic tire using the same (hereinafter, also simply referred to as “rubber composition” and “tire”, respectively).
  • the present invention relates to a rubber composition for an inner layer member of a tire that can achieve both high heat generation and crack growth resistance and a heavy-duty pneumatic tire using the same.
  • Patent Document 1 discloses a rubber composition for a tire tread that improves chipping resistance without deteriorating heat generation, and has high strength and elongation, and the performance can be maintained over a long period of time. Has been proposed.
  • the total amount of carbon black and silica having a nitrogen adsorption specific surface area (N 2 SA) of 90 m 2 / g or more with respect to 100 parts by weight of a diene rubber mainly composed of natural rubber and / or butadiene rubber is 30.
  • a rubber composition comprising ⁇ 70 parts by weight and less than 3 parts by weight of ultrahigh molecular weight polyethylene has been proposed. Although this rubber composition is a rubber composition for treads of heavy duty tires for icy and snowy roads, it is disclosed that deterioration of heat generation and fatigue resistance can be prevented.
  • the rubber used for the inner layer member of such a heavy duty pneumatic tire is required to have low heat generation and excellent wear resistance / cut resistance / tea resistance. From this point of view, the rubber compositions proposed in Patent Documents 1 and 2 are not necessarily sufficient in terms of low heat build-up and fracture resistance, which will be required for inner layer members of heavy duty pneumatic tires in the future. Absent.
  • an object of the present invention is to provide a rubber composition for an inner layer member of a tire and a heavy-duty pneumatic tire using the same, which can achieve both a low exothermic property and crack progress resistance at a higher level than before. There is.
  • a tire is manufactured by heating and vulcanizing an unvulcanized rubber composition.
  • the tire can reach the inside of the tire.
  • the vulcanization is performed under such a condition that the degree of vulcanization is larger than that of a tire for a general passenger car.
  • the present inventors have found that when vulcanization is performed under such conditions, the characteristics of the inner layer member such as low heat buildup and crack resistance are different from those of general passenger car tires. Based on such knowledge, the present inventors have made extensive studies to solve the above-mentioned problems. The present inventors have found that both can be achieved at a high level and have completed the present invention.
  • the rubber composition for an inner layer member of a tire according to the present invention is characterized in that silica, a thiuram compound, and a hydrazide compound are blended with a rubber component.
  • the rubber composition of the present invention 5 to 50 parts by mass of the silica, 0.1 to 2.0 parts by mass of the thiuram compound, and 0.1 to 2.0 parts of the hydrazide compound with respect to 100 parts by mass of the rubber component. It is preferably 5.0 parts by mass.
  • the nitrogen adsorption specific surface area of the said silica is 220 m ⁇ 2 > / g or more.
  • the rubber composition of the present invention preferably further contains carbon black.
  • the heavy duty pneumatic tire of the present invention is characterized in that the rubber composition for an inner layer member of the tire of the present invention is used for an inner layer member that is not in contact with an inner layer member other than rubber.
  • the gauge thickness of the tread portion is preferably 70 mm or more.
  • 1 is a schematic cross-sectional view in the width direction of a heavy duty pneumatic tire according to a preferred embodiment of the present invention. It is a general
  • the rubber composition for an inner layer member of a tire of the present invention is obtained by blending silica, a thiuram compound, and a hydrazide compound with a rubber component.
  • the type of rubber is not particularly limited.
  • natural rubber synthetic polyisoprene rubber (IR), polybutadiene (BR), styrene-butadiene copolymer (SBR), butyl rubber (IIR), ethylene-propylene-diene copolymer (EPDM), acrylonitrile-butadiene copolymer (NBR), rubbers combining these, and the like.
  • NR natural rubber
  • IR synthetic polyisoprene rubber
  • BR polybutadiene
  • SBR styrene-butadiene copolymer
  • IIR butyl rubber
  • EPDM ethylene-propylene-diene copolymer
  • NBR acrylonitrile-butadiene copolymer
  • the amount of silica is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the rubber component. If the addition amount of silica is less than 5 parts by mass, a sufficient decrease in exothermic property may not be observed. On the other hand, if it exceeds 50 parts by mass, the crack propagation resistance is excellent, but the low heat build-up may be inferior. More preferably, it is 10 to 20 parts by mass.
  • the silica used for the rubber composition of this invention there is no restriction
  • the silica preferably has a nitrogen adsorption specific surface area (BET specific surface area) of 80 m 2 / g or more, more preferably 220 m 2 / g or more. By using such silica, the effect of the present invention can be favorably obtained.
  • the nitrogen adsorption specific surface area is measured by a single point value of the BET method defined by a method based on ISO 5794/1.
  • silica may be used alone or in combination of two or more.
  • the amount of the thiuram compound is preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount of thiuram is less than 0.1 parts by mass, the effect of improving low heat build-up and crack resistance may not be seen. On the other hand, if blending more than 2.0 parts by mass, the scorch of rubber It may be difficult to process due to deterioration of the properties. More preferably, it is 0.2 to 1.0 part by mass.
  • the blending amount of the hydrazide compound is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount of the hydrazide compound is less than 0.1 parts by mass, the low heat build-up may be insufficient. Is not preferable. More preferred is 0.5 to 2.0 parts by mass.
  • Examples of the hydrazide compound used in the rubber composition of the present invention include isophthalic acid dihydrazide, adipic acid dihydrazide, isophthalic acid di (1,3-dimethylpropylidene) hydrazide, and 2-naphthalic acid-3-hydroxy (1,3- Dimethylpropylidene) hydrazide, 2-naphthalenic acid-3-hydroxy (1,3-dimethylbutylidene) hydrazide, salicylic acid (1,3-dimethylpropylidene) hydrazide, isonicotinic acid hydrazide, isonicotinic acid (1,3- Dimethylpropylidene) hydrazide, salicylic acid hydrazide, 2-naphthalenic acid-3-hydroxyhydrazide, salicylic acid (1-methylethylidene) hydrazide, 2-naphthalenic acid-3-hydroxyhydrazide, salicylic acid (1-methylethy
  • the rubber composition of the present invention preferably further contains carbon black.
  • the amount of carbon black added is preferably such that the total of silica and carbon black is 30 to 55 parts by mass. If the total of silica and carbon black is less than 30 parts by mass, the specific exothermic deterioration may not be observed. On the other hand, if the total of silica and carbon black exceeds 55 parts by mass, the crack resistance is improved. However, low exothermic properties may deteriorate.
  • the carbon black is not particularly limited.
  • high, medium or low structure SAF, ISAF, IISAF, N339, HAF, FEF, GPF, SRF grade carbon Black can be used.
  • those having an iodine absorption of 35 to 90 g / kg can be preferably used.
  • the iodine absorption is less than 35 g / kg, the low heat build-up property is excellent, but the crack resistance may be poor.
  • the iodine absorption exceeds 90 g / kg, the crack growth resistance is excellent, but the low heat build-up may be deteriorated.
  • the iodine adsorption amount is a value measured according to JIS K 62177-1: 2001.
  • the rubber composition of the present invention it is important only that silica, a thiuram compound and a hydrazide compound are used in combination in the rubber, and there is no particular limitation other than that.
  • various chemicals usually used in the rubber industry for example, a vulcanizing agent, a vulcanization accelerator, a softening agent, and an anti-aging agent, as long as the object of the present invention is not impaired.
  • Viscosity reducing agents, zinc white, stearic acid, and the like can be used as appropriate.
  • the vulcanizing agent examples include sulfur, and the amount of the vulcanizing agent is preferably 0.1 to 10.0 parts by mass, more preferably 1.0 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. Part. If the amount is less than 0.1 parts by mass, the fracture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by mass, rubber elasticity will be lost.
  • the vulcanization accelerator is not particularly limited.
  • M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazylsulfenamide) And guanidine vulcanization accelerators such as DPG (diphenylguanidine).
  • the blending amount is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 3.0 parts by mass with respect to 100 parts by mass of the rubber component.
  • process oil can be used, and examples thereof include paraffinic, naphthenic, and aromatic process oils.
  • an aromatic system is used for applications where importance is placed on tensile strength and wear resistance
  • a naphthenic system or paraffin system is used for applications where importance is placed on hysteresis loss and low temperature characteristics.
  • the blending amount is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the rubber component, and if it is 100 parts by mass or less, the deterioration of the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber is suppressed. can do.
  • antioxidants examples include 3C (N-isopropyl-N′-phenyl-p-phenylenediamine, 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine), AW ( 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), a high-temperature condensate of diphenylamine and acetone, etc.
  • the blending amount is about 0.
  • the amount is preferably 1 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass.
  • the rubber composition of the present invention is obtained by kneading using a kneading machine such as an open kneading machine such as a roll or a closed kneading machine such as a Banbury mixer. Applicable to products. Although there is no restriction
  • FIG. 1 is a schematic cross-sectional view in the width direction of a heavy duty pneumatic tire according to a preferred embodiment of the present invention.
  • the illustrated tire 20 includes a pair of bead portions 1, a pair of side portions 2, and a tread portion 3, and a carcass 5 that extends in a toroid shape between bead cores 4 embedded in the bead portions 1.
  • the belt 6 includes a plurality of belt layers arranged on the outer side in the tire radial direction at the crown portion of the carcass 5, and the bead filler 7 on the outer side in the tire radial direction of the bead core 4.
  • the tire 20 of the present invention is used as an inner layer member that is not in contact with an inner layer member other than rubber of a heavy duty pneumatic tire, that is, the rubber composition of the present invention is used as a material other than a coating rubber.
  • FIG. 2 is a schematic enlarged cross-sectional view of the vicinity of the belt end portion of the heavy duty pneumatic tire according to one preferred embodiment of the present invention.
  • the rubber composition of the present invention includes, for example, each belt. It can be suitably used for the belt end rubbers 8a to 8e covering the ends of the layers 6a to 6e and the end cushion rubber 9 disposed in the gap between the upper and lower belt layers at the end of the belt layer.
  • the rubber composition of the present invention is, for example, a carcass. It can be suitably used as the soft stiffener 10 disposed between the main body 5a and the folded portion 5b of the carcass 5 or the sidewall filler 11 disposed on the outer side in the tire width direction of the carcass folded portion 5b.
  • the rubber composition of the present invention can also be used as a base rubber for the tread portion.
  • the rubber composition of the present invention is more effective in an inner layer member of a tire that is excessively vulcanized such that the gauge thickness of the tread portion is 70 mm or more.
  • the gauge thickness of the tread is as large as 70 mm or more.
  • vulcanization is performed excessively as compared with a general passenger car tire or the like, and vulcanization is performed under such a condition that the degree of vulcanization is increased.
  • the rubber composition for an inner layer member of the present invention contains a rubber component, silica, a hydrazide compound, and a thiuram compound, so that the inner layer member rubber excellent in low heat buildup and crack resistance is obtained. can get.
  • the gauge thickness of the tread portion is the thickness of the outermost layer reinforcing layer from the outer surface in the tire radial direction to the outer surface of the tire, and means the value at the thinnest position.
  • members other than these are not particularly limited, and known members can be used.
  • an inert gas such as nitrogen, argon, helium, etc. can be used in addition to normal or air with adjusted oxygen partial pressure.
  • Examples 1 to 6 and Comparative Examples 1 to 11 Rubber compositions were prepared with the formulations shown in Tables 1 to 3 below. The resulting rubber composition was vulcanized under vulcanization conditions at 160 ° C. for 20 minutes to prepare a predetermined test piece, and then the crack resistance and low heat build-up were evaluated by the following procedures. In addition, the unit of the compounding quantity in a table
  • surface is a mass part.
  • tan ⁇ was measured at a temperature of 60 ° C., a dynamic strain of 5%, and a frequency of 15 Hz. A smaller index value indicates a lower exothermic property and a smaller hysteresis loss.
  • the rubber composition of the present invention can achieve both low heat buildup and crack growth resistance.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
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Abstract

Provided are: a rubber composition for an inner-layer member of a tire, the resin composition enabling the tire to combine low heat build-up properties with crack propagation resistance to a higher degree than conventional ones; and a heavy-duty pneumatic tire obtained using the rubber composition. The rubber composition is obtained by incorporating silica, a thiuram compound, and a hydrazide compound into a rubber ingredient.

Description

タイヤの内層部材用ゴム組成物およびこれを用いた重荷重用空気入りタイヤRubber composition for inner layer member of tire and pneumatic tire for heavy load using the same
　本発明は、タイヤの内層部材用ゴム組成物およびこれを用いた重荷重用空気入りタイヤ（以下、単に、それぞれ「ゴム組成物」、「タイヤ」とも称す）に関し、詳しくは、従来よりも、低発熱性と耐亀裂進展性とを高度に両立することができるタイヤの内層部材用ゴム組成物およびこれを用いた重荷重用空気入りタイヤに関する。 The present invention relates to a rubber composition for an inner layer member of a tire and a heavy duty pneumatic tire using the same (hereinafter, also simply referred to as “rubber composition” and “tire”, respectively). The present invention relates to a rubber composition for an inner layer member of a tire that can achieve both high heat generation and crack growth resistance and a heavy-duty pneumatic tire using the same.
　大型車両用、重荷重用空気入りタイヤには、低燃費性およびタイヤの寿命の観点から、低発熱性を損なうことなく、耐摩耗性を向上させることが要求され、さらには、耐亀裂進展性等の耐破壊性も重要な特性となっている。このような課題に対して、例えば、特許文献１では、発熱を悪化させることなく、耐チッピング性を改良し、しかも強度、伸びが高くかつその性能を長期にわたって持続可能なタイヤトレッド用ゴム組成物が提案されている。 For heavy vehicles and heavy-duty pneumatic tires, from the viewpoint of low fuel consumption and tire life, it is required to improve wear resistance without impairing low heat build-up, and crack resistance, etc. The fracture resistance is also an important characteristic. For such a problem, for example, Patent Document 1 discloses a rubber composition for a tire tread that improves chipping resistance without deteriorating heat generation, and has high strength and elongation, and the performance can be maintained over a long period of time. Has been proposed.
　また、特許文献２では、天然ゴムおよび／またはブタジエンゴムを主体としたジエン系ゴム１００重量部に対し、窒素吸着比表面積（Ｎ２ＳＡ）が９０ｍ２／ｇ以上のカーボンブラックとシリカの総量３０～７０重量部、および超高分子量ポリエチレン３重量部未満を配合してなるゴム組成物が提案されている。このゴム組成物は、氷雪路向け重荷重用タイヤのトレッド用ゴム組成物であるが、発熱性および耐疲労性の悪化を防止できることが開示されている。 In Patent Document 2, the total amount of carbon black and silica having a nitrogen adsorption specific surface area (N 2 SA) of 90 m 2 / g or more with respect to 100 parts by weight of a diene rubber mainly composed of natural rubber and / or butadiene rubber is 30. A rubber composition comprising ˜70 parts by weight and less than 3 parts by weight of ultrahigh molecular weight polyethylene has been proposed. Although this rubber composition is a rubber composition for treads of heavy duty tires for icy and snowy roads, it is disclosed that deterioration of heat generation and fatigue resistance can be prevented.
特開２００５－２２５９０９号公報JP 2005-225909 A 特開２００６－２４１３３８号公報JP 2006-241338 A
　特に、近年の重荷重車両のタイヤの大型化、車両の高出力化に対応すべく、走行時のタイヤ発熱性と耐破壊性能を向上させる必要がある。このような、重荷重用空気入りタイヤの内層部材に用いられるゴムには、低発熱であるとともに耐摩耗性／耐カット性／耐テアー性に優れることが要求される。このような観点からすると、特許文献１および２で提案されているゴム組成物では、重荷重用空気入りタイヤの内層部材に今後求められるであろう低発熱性と耐破壊性能に関しては、必ずしも十分ではない。 Especially, it is necessary to improve the tire heat generation property and the anti-destructive performance during running in order to cope with the recent increase in size of tires of heavy-duty vehicles and high output of vehicles. The rubber used for the inner layer member of such a heavy duty pneumatic tire is required to have low heat generation and excellent wear resistance / cut resistance / tea resistance. From this point of view, the rubber compositions proposed in Patent Documents 1 and 2 are not necessarily sufficient in terms of low heat build-up and fracture resistance, which will be required for inner layer members of heavy duty pneumatic tires in the future. Absent.
　例えば、耐摩耗性、耐カット性向上手法としては、タイヤ用ゴムの主たる充填剤であるカーボンブラック（ＣＢ）の増量、微粒径化（ＣＢグレードアップ）が知られているが、発熱性の確保とは相反することになる。また従来からの手法として、ゴム組成物にシリカを配合することも行われてきた。これはヒステリシスロスを高くし、悪路チッピング等に効果があることが知られている。しかしながら、弾性率の低下や長時間加硫における加硫戻りによる発熱性の低下および作業性の著しい悪化により、シリカを多量に配合することは工場では現実的には困難であった。また、シリカとヒドラジド化合物を組み合わせて低発熱性と耐亀裂進展性を向上させる技術も知られているが、未だ不十分である。 For example, as a technique for improving wear resistance and cut resistance, increasing the amount of carbon black (CB), which is the main filler of tire rubber, and reducing the particle size (CB upgrade) are known. This is contrary to securing. In addition, as a conventional method, silica has been blended into a rubber composition. This is known to increase hysteresis loss and to be effective for rough road chipping and the like. However, due to a decrease in elastic modulus, a decrease in exothermicity due to reversion during long-term vulcanization, and a significant deterioration in workability, it was practically difficult to mix silica in a factory. A technique for improving low heat build-up and crack resistance by combining silica and a hydrazide compound is also known, but it is still insufficient.
　そこで、本発明の目的は、従来よりも、低発熱性と耐亀裂進展性とを高度に両立することができるタイヤの内層部材用ゴム組成物およびこれを用いた重荷重用空気入りタイヤを提供することにある。 Accordingly, an object of the present invention is to provide a rubber composition for an inner layer member of a tire and a heavy-duty pneumatic tire using the same, which can achieve both a low exothermic property and crack progress resistance at a higher level than before. There is.
　一般に、タイヤは、未加硫のゴム組成物を加熱して加硫させることで製造されるが、産業用の大型タイヤのような、トレッドのゲージ厚が７０ｍｍ以上のタイヤでは、タイヤの内部まで加硫を進行させるために、一般乗用車用タイヤ等に比べて、加硫度が大きくなるような条件にて加硫が行われる。本発明者等は、このような条件で加硫が行われた場合に、内層部材の低発熱性や耐亀裂性等の特性が一般乗用車用タイヤ等とは異なるものとなることを見出した。かかる知見に基づき、本発明者らは、上記課題を解消するために鋭意検討した結果、ゴム組成物にシリカ、チウラム化合物およびヒドラジド化合物を配合することにより、低発熱性と耐亀裂進展性とを高度に両立させることができることを見出し、本発明を完成するに至った。 In general, a tire is manufactured by heating and vulcanizing an unvulcanized rubber composition. However, in a tire having a tread gauge thickness of 70 mm or more, such as an industrial large tire, the tire can reach the inside of the tire. In order to advance the vulcanization, the vulcanization is performed under such a condition that the degree of vulcanization is larger than that of a tire for a general passenger car. The present inventors have found that when vulcanization is performed under such conditions, the characteristics of the inner layer member such as low heat buildup and crack resistance are different from those of general passenger car tires. Based on such knowledge, the present inventors have made extensive studies to solve the above-mentioned problems. The present inventors have found that both can be achieved at a high level and have completed the present invention.
　すなわち、本発明のタイヤの内層部材用ゴム組成物は、ゴム成分に対して、シリカと、チウラム化合物と、ヒドラジド化合物と、が配合されてなることを特徴とするものである。 That is, the rubber composition for an inner layer member of a tire according to the present invention is characterized in that silica, a thiuram compound, and a hydrazide compound are blended with a rubber component.
　本発明のゴム組成物においては、前記ゴム成分１００質量部に対して、前記シリカは５～５０質量部、前記チウラム化合物は０．１～２．０質量部、前記ヒドラジド化合物は０．１～５．０質量部であることが好ましい。また、本発明のゴム組成物においては、前記シリカの窒素吸着比表面積は２２０ｍ２／ｇ以上であることが好ましい。さらに、本発明のゴム組成物においては、さらに、カーボンブラックが配合されてなることが好ましい。 In the rubber composition of the present invention, 5 to 50 parts by mass of the silica, 0.1 to 2.0 parts by mass of the thiuram compound, and 0.1 to 2.0 parts of the hydrazide compound with respect to 100 parts by mass of the rubber component. It is preferably 5.0 parts by mass. Moreover, in the rubber composition of this invention, it is preferable that the nitrogen adsorption specific surface area of the said silica is 220 m < 2 > / g or more. Further, the rubber composition of the present invention preferably further contains carbon black.
　本発明の重荷重用空気入りタイヤは、本発明のタイヤの内層部材用ゴム組成物が、ゴム以外の内層部材に接しない内層部材に用いられてなることを特徴とするものである。 The heavy duty pneumatic tire of the present invention is characterized in that the rubber composition for an inner layer member of the tire of the present invention is used for an inner layer member that is not in contact with an inner layer member other than rubber.
　本発明の重荷重用空気入りタイヤにおいては、トレッド部のゲージ厚は７０ｍｍ以上であることが好ましい。 In the heavy duty pneumatic tire of the present invention, the gauge thickness of the tread portion is preferably 70 mm or more.
　本発明によれば、従来よりも、低発熱性と耐亀裂進展性とを高度に両立することができるタイヤの内層部材用ゴム組成物およびこれを用いた重荷重用空気入りタイヤを提供することができる。 According to the present invention, it is possible to provide a rubber composition for an inner layer member of a tire and a heavy-duty pneumatic tire using the same, which can achieve both low exothermic property and crack progress resistance at a higher level than before. it can.
本発明の一好適な実施の形態に係る重荷重用空気入りタイヤの幅方向概略断面図である。1 is a schematic cross-sectional view in the width direction of a heavy duty pneumatic tire according to a preferred embodiment of the present invention. 本発明の一好適な実施の形態に係る重荷重用空気入りタイヤのベルト端部近傍の概略拡大断面図である。It is a general | schematic expanded sectional view of the belt edge part vicinity of the heavy duty pneumatic tire which concerns on one suitable embodiment of this invention. 本発明の一好適な実施の形態に係る重荷重用空気入りタイヤのビード部近傍の概略拡大断面図である。1 is a schematic enlarged cross-sectional view in the vicinity of a bead portion of a heavy duty pneumatic tire according to a preferred embodiment of the present invention.
　以下、本発明のタイヤの内層部材用ゴム組成物について、詳細に説明する。
　本発明のタイヤの内層部材用ゴム組成物は、ゴム成分に対して、シリカと、チウラム化合物と、ヒドラジド化合物と、が配合されてなるものである。このように、シリカ、チウラム化合物およびヒドラジド化合物の配合量を併用することで、特異的に低発熱性と耐破壊性能、特に耐亀裂進展性とを向上させることができる。 Hereinafter, the rubber composition for the inner layer member of the tire of the present invention will be described in detail.
The rubber composition for an inner layer member of a tire of the present invention is obtained by blending silica, a thiuram compound, and a hydrazide compound with a rubber component. Thus, by using the compounding amounts of silica, thiuram compound and hydrazide compound in combination, it is possible to specifically improve the low heat buildup and fracture resistance, particularly crack resistance.
　本発明のゴム組成物においては、ゴムの種類については特に制限はない。例えば、具体的には、天然ゴム（ＮＲ）、合成ポリイソプレンゴム（ＩＲ）、ポリブタジエン（ＢＲ）、スチレン－ブタジエン共重合体（ＳＢＲ）、ブチルゴム（ＩＩＲ）、エチレン－プロピレン－ジエン共重合体（ＥＰＤＭ）、アクリロニトリル－ブタジエン共重合体（ＮＢＲ）、およびこれらを組み合わせたゴム等が挙げられる。これらの中でも、特に、ＮＲ、ＢＲ、ＳＢＲおよびこれらの組み合わせが好ましい。 In the rubber composition of the present invention, the type of rubber is not particularly limited. For example, natural rubber (NR), synthetic polyisoprene rubber (IR), polybutadiene (BR), styrene-butadiene copolymer (SBR), butyl rubber (IIR), ethylene-propylene-diene copolymer ( EPDM), acrylonitrile-butadiene copolymer (NBR), rubbers combining these, and the like. Among these, NR, BR, SBR and combinations thereof are particularly preferable.
　本発明のゴム組成物においては、シリカの配合量は、好ましくは、ゴム成分１００質量部に対して５～５０質量部である。シリカの添加量が５質量部未満では、十分な発熱性の低下は見られない場合がある。一方、５０質量部を超えると、耐亀裂進展性には優れるが、低発熱性が劣ってしまう場合がある。より好ましくは１０～２０質量部である。 In the rubber composition of the present invention, the amount of silica is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the rubber component. If the addition amount of silica is less than 5 parts by mass, a sufficient decrease in exothermic property may not be observed. On the other hand, if it exceeds 50 parts by mass, the crack propagation resistance is excellent, but the low heat build-up may be inferior. More preferably, it is 10 to 20 parts by mass.
　本発明のゴム組成物に用いるシリカには、特に制限はなく、市販のゴム組成物に使用されているものが使用できる。中でも湿式シリカ（含水ケイ酸）、乾式シリカ（無水ケイ酸）、コロイダルシリカ等を使用することができ、特に、湿式シリカが好ましい。本発明のゴム組成物においては、シリカとしては、窒素吸着比表面積（ＢＥＴ比表面積）が８０ｍ２／ｇ以上のものが好ましく、２２０ｍ２／ｇ以上のものがより好ましい。このようなシリカを用いることで、本発明の効果を良好に得ることができる。なお、窒素吸着比表面積は、ＩＳＯ５７９４／１に準拠した方法によって規定されるＢＥＴ法の一点値により測定されるものである。また、本発明のゴム組成物においては、シリカは１種単独で用いてもよいが、２種以上を併用してもよい。 There is no restriction | limiting in particular in the silica used for the rubber composition of this invention, The thing currently used for the commercially available rubber composition can be used. Among these, wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), colloidal silica and the like can be used, and wet silica is particularly preferable. In the rubber composition of the present invention, the silica preferably has a nitrogen adsorption specific surface area (BET specific surface area) of 80 m 2 / g or more, more preferably 220 m 2 / g or more. By using such silica, the effect of the present invention can be favorably obtained. The nitrogen adsorption specific surface area is measured by a single point value of the BET method defined by a method based on ISO 5794/1. In the rubber composition of the present invention, silica may be used alone or in combination of two or more.
　また、本発明のゴム組成物においては、チウラム化合物の配合量は、好ましくは、ゴム成分１００質量部に対して０．１～２．０質量部である。チウラムの配合量が０．１質量部未満であると、低発熱性と耐亀裂進展性の向上効果が見られない場合があり、一方、２．０質量部よりも多く配合すると、ゴムのスコーチ性が悪化して加工が困難になる場合がある。より好ましくは０．２～１．０質量部である。 In the rubber composition of the present invention, the amount of the thiuram compound is preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount of thiuram is less than 0.1 parts by mass, the effect of improving low heat build-up and crack resistance may not be seen. On the other hand, if blending more than 2.0 parts by mass, the scorch of rubber It may be difficult to process due to deterioration of the properties. More preferably, it is 0.2 to 1.0 part by mass.
　本発明のゴム組成物に用いることができるチウラム化合物としては、テトラメチルチウラムモノスルフィド（ＴＳ）、テトラメチルチウラムジスルフィド（ＴＴ）、テトラエチルチウラムジスルフィド（ＴＥＴ）、ジペンタメチレンチウラムヘキサスルフィド（ＴＲＡ）、テトラブチルチウラムジスルフィド（ＴＢＴ）、テトラキス（２－エチルヘキシル）チウラムジスルフィド（ＴＯＴ）、テトラベンジルチウラムジスルフィド（ＴＢＺＴＤ）等が挙げられる。本発明のゴム組成物においては、これらチウラム化合物を１種単独で用いてもよいが、２種以上を併用してもよい。 Examples of thiuram compounds that can be used in the rubber composition of the present invention include tetramethylthiuram monosulfide (TS), tetramethylthiuram disulfide (TT), tetraethylthiuram disulfide (TET), dipentamethylene thiuram hexasulfide (TRA), Examples thereof include tetrabutyl thiuram disulfide (TBT), tetrakis (2-ethylhexyl) thiuram disulfide (TOT), and tetrabenzyl thiuram disulfide (TB Z TD). In the rubber composition of the present invention, these thiuram compounds may be used alone or in combination of two or more.
　また、本発明のゴム組成物においては、ヒドラジド化合物の配合量は、好ましくは、ゴム成分１００質量部に対して０．１～５．０質量部である。ヒドラジド化合物の配合量が０．１質量部未満であると、低発熱性が不十分な場合があり、一方、５．０質量部より多く添加しても、得られる効果に差がなくなり、コスト的に好ましくない。より好ましくは０．５～２．０質量部である。 In the rubber composition of the present invention, the blending amount of the hydrazide compound is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount of the hydrazide compound is less than 0.1 parts by mass, the low heat build-up may be insufficient. Is not preferable. More preferred is 0.5 to 2.0 parts by mass.
　本発明のゴム組成物に用いるヒドラジド化合物としては、例えば、イソフタル酸ジヒドラジド、アジピン酸ジヒドラジド、イソフタル酸ジ（１，３－ジメチルプロピリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１，３－ジメチルプロピリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１，３－ジメチルブチリデン）ヒドラジド、サリチル酸（１，３－ジメチルプロピリデン）ヒドラジド、イソニコチン酸ヒドラジド、イソニコチン酸（１，３－ジメチルプロピリデン）ヒドラジド、サリチル酸ヒドラジド、２－ナフタレン酸－３－ヒドロキシヒドラジド、サリチル酸（１－メチルエチリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１－メチルエチリデン）ヒドラジド、サリチル酸（１－メチルプロピリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１－メチルプロピリデン）ヒドラジド、サリチル酸（１，３－ジメチルプロピリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１，３－ジメチルプロピリデン）ヒドラジド、サリチル酸（１－フェニルエチリデン）ヒドラジド、２－ナフタレン酸－３－ヒドロキシ（１－フェニルエチリデン）ヒドラジドイソニコチン酸ヒドラジド、イソニコチン酸（１－メチルエチリデン）ヒドラジド、イソニコチン酸（１－メチルプロピリデン）ヒドラジド、イソニコチン酸（１，３－ジメチルプロピリデン）ヒドラジド、イソニコチン酸（１－フェニルエチリデン）ヒドラジド等が挙げられる。なお、本発明のゴム組成物においては、これらヒドラジド化合物は１種単独で用いてもよいが、２種以上を併用してもよい。 Examples of the hydrazide compound used in the rubber composition of the present invention include isophthalic acid dihydrazide, adipic acid dihydrazide, isophthalic acid di (1,3-dimethylpropylidene) hydrazide, and 2-naphthalic acid-3-hydroxy (1,3- Dimethylpropylidene) hydrazide, 2-naphthalenic acid-3-hydroxy (1,3-dimethylbutylidene) hydrazide, salicylic acid (1,3-dimethylpropylidene) hydrazide, isonicotinic acid hydrazide, isonicotinic acid (1,3- Dimethylpropylidene) hydrazide, salicylic acid hydrazide, 2-naphthalenic acid-3-hydroxyhydrazide, salicylic acid (1-methylethylidene) hydrazide, 2-naphthalenic acid-3-hydroxy (1-methylethylidene) hydrazide, salicylic acid (1-methylpropylidene) Den) hydrazide, 2-naphthalenic acid-3-hydroxy (1-methylpropylidene) hydrazide, salicylic acid (1,3-dimethylpropylidene) hydrazide, 2-naphthalenic acid-3-hydroxy (1,3-dimethylpropylidene) Hydrazide, salicylic acid (1-phenylethylidene) hydrazide, 2-naphthalenic acid-3-hydroxy (1-phenylethylidene) hydrazide isonicotinic acid hydrazide, isonicotinic acid (1-methylethylidene) hydrazide, isonicotinic acid (1-methylpropiide) Ridene) hydrazide, isonicotinic acid (1,3-dimethylpropylidene) hydrazide, isonicotinic acid (1-phenylethylidene) hydrazide and the like. In the rubber composition of the present invention, these hydrazide compounds may be used alone or in combination of two or more.
　本発明のゴム組成物においては、さらに、カーボンブラックが配合されてなることが好ましい。カーボンブラックの添加量は、好適には、シリカとカーボンブラックとの合計が３０～５５質量部となるように配合する。シリカとカーボンブラックの合計が３０質量部未満では、特異的な発熱性の低下が見られない場合があり、一方、シリカとカーボンブラックの合計が５５質量部を超えると、耐亀裂進展性は向上するが低発熱性が悪化する場合がある。 The rubber composition of the present invention preferably further contains carbon black. The amount of carbon black added is preferably such that the total of silica and carbon black is 30 to 55 parts by mass. If the total of silica and carbon black is less than 30 parts by mass, the specific exothermic deterioration may not be observed. On the other hand, if the total of silica and carbon black exceeds 55 parts by mass, the crack resistance is improved. However, low exothermic properties may deteriorate.
　本発明のゴム組成物においては、カーボンブラックについては、特に制限されるものではないが、例えば、高、中または低ストラクチャーのＳＡＦ、ＩＳＡＦ、ＩＩＳＡＦ、Ｎ３３９、ＨＡＦ、ＦＥＦ、ＧＰＦ、ＳＲＦグレードのカーボンブラックを使用できる。中でも特に、ヨウ素吸収量が３５～９０ｇ／ｋｇのものを好適に用いることができる。ヨウ素吸収量が３５ｇ／ｋｇ未満の場合、低発熱性に優れるが、耐亀裂進展性に劣る場合がある。一方、ヨウ素吸収量が９０ｇ／ｋｇを超える場合には、耐亀裂進展性に優れるが、低発熱性が悪化する場合がある。なお、ヨウ素吸着量はＪＩＳ　Ｋ　６２１７－１：２００１に準拠して測定した値である。 In the rubber composition of the present invention, the carbon black is not particularly limited. For example, high, medium or low structure SAF, ISAF, IISAF, N339, HAF, FEF, GPF, SRF grade carbon Black can be used. Among them, those having an iodine absorption of 35 to 90 g / kg can be preferably used. When the iodine absorption is less than 35 g / kg, the low heat build-up property is excellent, but the crack resistance may be poor. On the other hand, when the iodine absorption exceeds 90 g / kg, the crack growth resistance is excellent, but the low heat build-up may be deteriorated. The iodine adsorption amount is a value measured according to JIS K 62177-1: 2001.
　本発明のゴム組成物は、ゴム中に、シリカ、チウラム化合物およびヒドラジド化合物が併用されていることのみが重要であり、それ以外に特に制限はない。本発明のゴム組成物には、本発明の目的が損なわれない範囲で、所望により、通常、ゴム工業界で用いられる各種薬品、例えば加硫剤、加硫促進剤、軟化剤、老化防止剤、粘度低減剤、亜鉛華、ステアリン酸等を適宜使用することができる。 In the rubber composition of the present invention, it is important only that silica, a thiuram compound and a hydrazide compound are used in combination in the rubber, and there is no particular limitation other than that. In the rubber composition of the present invention, various chemicals usually used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, a softening agent, and an anti-aging agent, as long as the object of the present invention is not impaired. Viscosity reducing agents, zinc white, stearic acid, and the like can be used as appropriate.
　加硫剤としては硫黄等が挙げられ、その配合量は、ゴム成分１００質量部に対し、硫黄分として０．１～１０．０質量部が好ましく、さらに好ましくは１．０～５．０質量部である。０．１質量部未満では加硫ゴムの破壊強度、耐摩耗性、低発熱性が低下するおそれがあり、１０．０質量部を超えるとゴム弾性が失われることになる。 Examples of the vulcanizing agent include sulfur, and the amount of the vulcanizing agent is preferably 0.1 to 10.0 parts by mass, more preferably 1.0 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. Part. If the amount is less than 0.1 parts by mass, the fracture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by mass, rubber elasticity will be lost.
　加硫促進剤としては、特に限定されるものではないが、例えば、Ｍ（２－メルカプトベンゾチアゾール）、ＤＭ（ジベンゾチアジルジスルフィド）、ＣＺ（Ｎ－シクロヘキシル－２－ベンゾチアジルスルフェンアミド）等のスルフェンアミド系、ＤＰＧ（ジフェニルグアニジン）等のグアニジン系の加硫促進剤を挙げることができる。その配合量は、ゴム成分１００質量部に対し、０．１～５．０質量部が好ましく、より好ましくは０．２～３．０質量部である。 The vulcanization accelerator is not particularly limited. For example, M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazylsulfenamide) And guanidine vulcanization accelerators such as DPG (diphenylguanidine). The blending amount is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 3.0 parts by mass with respect to 100 parts by mass of the rubber component.
　軟化剤としては、プロセス油を用いることができ、例えば、パラフィン系、ナフテン系、アロマチック系等のプロセス油を挙げることができる。例えば、引張強度、耐摩耗性を重視する用途にはアロマチック系が、ヒステリシスロス、低温特性を重視する用途にはナフテン系またはパラフィン系が用いられる。その配合量は、ゴム成分１００質量部に対して、０～１００質量部が好ましく、１００質量部以下であれば加硫ゴムの引張強度、低発熱性（低燃費性）が悪化するのを抑制することができる。 As the softener, process oil can be used, and examples thereof include paraffinic, naphthenic, and aromatic process oils. For example, an aromatic system is used for applications where importance is placed on tensile strength and wear resistance, and a naphthenic system or paraffin system is used for applications where importance is placed on hysteresis loss and low temperature characteristics. The blending amount is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the rubber component, and if it is 100 parts by mass or less, the deterioration of the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber is suppressed. can do.
　老化防止剤としては、例えば、３Ｃ（Ｎ－イソプロピル－Ｎ’－フェニル－ｐ－フェニレンジアミン、６Ｃ（Ｎ－（１，３－ジメチルブチル）－Ｎ’－フェニル－ｐ－フェニレンジアミン）、ＡＷ（６－エトキシ－２，２，４－トリメチル－１，２－ジヒドロキノリン）、ジフェニルアミンとアセトンの高温縮合物等を挙げることができる。その配合量は、ゴム成分１００質量部に対して、０．１～５．０質量部が好ましく、より好ましくは０．３～３．０質量部である。 Examples of the antioxidant include 3C (N-isopropyl-N′-phenyl-p-phenylenediamine, 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine), AW ( 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), a high-temperature condensate of diphenylamine and acetone, etc. The blending amount is about 0. The amount is preferably 1 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass.
　本発明のゴム組成物は、ロール等の開放式混練機、バンバリーミキサー等の密閉式混練機等の混練り機を用いて混練りすることによって得られ、成形加工後に加硫を行ない、各種ゴム製品に適用可能である。本発明のゴム組成物の用途については特に制限はないが、低発熱性、耐亀裂進展性に優れているため、重荷重用空気入りタイヤの軟スティフナー、ベルトエンドインサーション、サイドウォールフィラー等に用いることもできるが、ベースゴムとしても用いることもできる。 The rubber composition of the present invention is obtained by kneading using a kneading machine such as an open kneading machine such as a roll or a closed kneading machine such as a Banbury mixer. Applicable to products. Although there is no restriction | limiting in particular about the use of the rubber composition of this invention, Since it is excellent in low heat buildup and crack progress resistance, it uses for the soft stiffener of a heavy duty pneumatic tire, a belt end insertion, a sidewall filler, etc. It can also be used as a base rubber.
　次に、本発明の重荷重用空気入りタイヤについて、図面を用いて説明する。
　図１は、本発明の一好適な実施の形態に係る重荷重用空気入りタイヤの幅方向概略断面図である。図示するタイヤ２０は、一対のビード部１と、一対のサイド部２と、トレッド部３とを有し、ビード部１に各々埋設されたビードコア４間にトロイド状に延在させたカーカス５と、カーカス５のクラウン部でタイヤ径方向外側に配した複数のベルト層からなるベルト６と、ビードコア４のタイヤ径方向外側にビードフィラー７と、を備えている。 Next, the heavy duty pneumatic tire of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view in the width direction of a heavy duty pneumatic tire according to a preferred embodiment of the present invention. The illustrated tire 20 includes a pair of bead portions 1, a pair of side portions 2, and a tread portion 3, and a carcass 5 that extends in a toroid shape between bead cores 4 embedded in the bead portions 1. The belt 6 includes a plurality of belt layers arranged on the outer side in the tire radial direction at the crown portion of the carcass 5, and the bead filler 7 on the outer side in the tire radial direction of the bead core 4.
　本発明のタイヤ２０は、重荷重用空気入りタイヤのゴム以外の内層部材に接しない内層部材に、すなわち、本発明のゴム組成物は、コーティングゴム以外として用いられる。図２は、本発明の一好適な実施の形態に係る重荷重用空気入りタイヤのベルト端部近傍の概略拡大断面図であり、図示する様に、本発明のゴム組成物は、例えば、各ベルト層６ａ～６ｅの端部を覆うベルトエンドゴム８ａ～８ｅや、ベルト層端部における上下のベルト層の隙間に配置される端クッションゴム９に、好適に用いることができる。また、図３は、本発明の一好適な実施の形態に係る重荷重用空気入りタイヤのビード部近傍の概略拡大断面図であり、図示する様に、本発明のゴム組成物は、例えば、カーカス５ａ本体とカーカス５の折り返し部５ｂとの間に配置される軟スティフナー１０や、カーカス折り返し部５ｂのタイヤ幅方向外側に配置されるサイドウォールフィラー１１として好適に用いることができる。また、本発明のゴム組成物は、トレッド部のベースゴムとして用いることもできる。 The tire 20 of the present invention is used as an inner layer member that is not in contact with an inner layer member other than rubber of a heavy duty pneumatic tire, that is, the rubber composition of the present invention is used as a material other than a coating rubber. FIG. 2 is a schematic enlarged cross-sectional view of the vicinity of the belt end portion of the heavy duty pneumatic tire according to one preferred embodiment of the present invention. As shown in FIG. 2, the rubber composition of the present invention includes, for example, each belt. It can be suitably used for the belt end rubbers 8a to 8e covering the ends of the layers 6a to 6e and the end cushion rubber 9 disposed in the gap between the upper and lower belt layers at the end of the belt layer. FIG. 3 is a schematic enlarged cross-sectional view of the vicinity of the bead portion of the heavy duty pneumatic tire according to one preferred embodiment of the present invention. As shown in the figure, the rubber composition of the present invention is, for example, a carcass. It can be suitably used as the soft stiffener 10 disposed between the main body 5a and the folded portion 5b of the carcass 5 or the sidewall filler 11 disposed on the outer side in the tire width direction of the carcass folded portion 5b. The rubber composition of the present invention can also be used as a base rubber for the tread portion.
　本発明のゴム組成物は、トレッド部のゲージ厚が７０ｍｍ以上という加硫が過度に行われるタイヤの内層部材において、より効果を発揮する。例えば、産業用の大型タイヤでは、トレッドのゲージ厚が７０ｍｍ以上と厚みが大きい。このようなタイヤの内部まで加硫を進行させるために、一般乗用車用タイヤ等に比べて加硫が過度に行われ、加硫度が大きくなるような条件にて加硫が行われる。このような条件下において、本発明の内層部材用ゴム組成物においては、ゴム成分、シリカ、ヒドラジド化合物、およびチウラム化合物を含有することで、低発熱性および耐亀裂性に優れる内層部材用ゴムが得られる。なお、トレッド部のゲージ厚とは、最外層補強層のタイヤ径方向外面からタイヤ外表面までの厚さであり、最も薄い位置の値を意味する。 The rubber composition of the present invention is more effective in an inner layer member of a tire that is excessively vulcanized such that the gauge thickness of the tread portion is 70 mm or more. For example, in a large industrial tire, the gauge thickness of the tread is as large as 70 mm or more. In order to advance the vulcanization to the inside of such a tire, vulcanization is performed excessively as compared with a general passenger car tire or the like, and vulcanization is performed under such a condition that the degree of vulcanization is increased. Under such conditions, the rubber composition for an inner layer member of the present invention contains a rubber component, silica, a hydrazide compound, and a thiuram compound, so that the inner layer member rubber excellent in low heat buildup and crack resistance is obtained. can get. The gauge thickness of the tread portion is the thickness of the outermost layer reinforcing layer from the outer surface in the tire radial direction to the outer surface of the tire, and means the value at the thinnest position.
　なお、本発明のタイヤ２０においては、これら以外の部材については、特に限定されず、公知の部材を使用することができる。また、本発明のタイヤ２０に充填する気体としては、通常の、または酸素分圧を調整した空気の他、窒素、アルゴン、ヘリウム等の不活性ガスを用いることができる。 In the tire 20 of the present invention, members other than these are not particularly limited, and known members can be used. Moreover, as gas with which the tire 20 of the present invention is filled, an inert gas such as nitrogen, argon, helium, etc. can be used in addition to normal or air with adjusted oxygen partial pressure.
　以下、本発明を、実施例を用いてより詳細に説明する。
＜実施例１～６および比較例１～１１＞
　下記表１～３に示す配合でゴム組成物を調製した。得られたゴム組成物につき、１６０℃、２０分の加硫条件で加硫して所定の試験片を作成した後、耐亀裂進展性および低発熱性を下記の手順で評価した。なお、表中の配合量の単位は質量部である。 Hereinafter, the present invention will be described in more detail with reference to examples.
<Examples 1 to 6 and Comparative Examples 1 to 11>
Rubber compositions were prepared with the formulations shown in Tables 1 to 3 below. The resulting rubber composition was vulcanized under vulcanization conditions at 160 ° C. for 20 minutes to prepare a predetermined test piece, and then the crack resistance and low heat build-up were evaluated by the following procedures. In addition, the unit of the compounding quantity in a table | surface is a mass part.
＜耐亀裂進展性＞
　ＪＩＳ　Ｋ　６２７０：２０１０「加硫ゴム及び熱可塑性ゴム－引張疲労特性の求め方－定ひずみ方法」に従って、２３℃で各ゴム組成物の繰り返し引張試験を行い、疲労寿命（破断までの繰り返し引張回数）を測定し、比較例１を基準１００として指数表示した。指数値が大きい程、耐亀裂進展性が良好であることを示す。なお、ダンベル状３号試験片を用い、試験ひずみは１００％とし、試験周波数は３Ｈｚで行なった。 <Crack resistance>
According to JIS K 6270: 2010 “Vulcanized rubber and thermoplastic rubber – Determination of tensile fatigue properties – Constant strain method”, each rubber composition was subjected to repeated tensile tests at 23 ° C., and fatigue life (the number of repeated tensions until breakage). ) Was measured and indexed with Comparative Example 1 as the reference 100. The larger the index value, the better the crack resistance. A dumbbell-shaped No. 3 test piece was used, the test strain was 100%, and the test frequency was 3 Hz.
＜低発熱性＞
　粘弾性測定装置（レオメトリックス社製）を使用し、温度６０℃、動歪み５％、周波数１５Ｈｚでｔａｎδを測定し、比較例１を基準１００として指数表示した。指数値が小さい程、低発熱性であり、ヒステリシスロスが小さいことを示す。 <Low heat generation>
Using a viscoelasticity measuring device (Rheometrics Co., Ltd.), tan δ was measured at a temperature of 60 ° C., a dynamic strain of 5%, and a frequency of 15 Hz. A smaller index value indicates a lower exothermic property and a smaller hysteresis loss.
＜タイヤ耐久性＞
　（耐亀裂進展性－１００）＋（１００－低発熱性）の値が、４０以上である場合は、耐亀裂進展性および低発熱性を高度に両立したものであり◎、０より大きく４０未満である場合は、耐亀裂進展性および低発熱性を両立したものであり○、０以下である場合が、耐亀裂進展性と低発熱性のどちらかまたは両方が悪化したものであり×、と示した。 <Tire durability>
When the value of (crack resistance −100) + (100−low exothermic property) is 40 or more, crack progress resistance and low exothermic property are both highly compatible, and greater than 0 and less than 40 , The crack growth resistance and low heat build-up are both compatible, and the case where it is 0 or less is one in which either or both of the crack progress resistance and low heat build-up are deteriorated. Indicated.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
 ※１：ＲＳＳ＃３
※２：♯１５００（ＪＳＲ株式会社製）
※３：ＢＲ０１（宇部興産株式会社製）
※４：旭♯５５（旭カーボン株式会社製）
※５：旭♯７０（旭カーボン株式会社製）
※６：旭♯８０（旭カーボン株式会社製）
※７：２－ナフタレン酸－３－ヒドロキシ（１，３－ジメチルブチリデン）ヒドラジド
※８：２－ナフタレン酸－３－ヒドロキシ（１－メチルエチリデン）ヒドラジド
※９：ニップシールＥＲ（東ソー・シリカ株式会社製、ＢＥＴ比表面積９５ｍ２／ｇ）
※１０：ニップシールＡＱ（東ソー・シリカ株式会社製、ＢＥＴ比表面積２０５ｍ２／ｇ）
※１１：ニップシールＫＱ（東ソー・シリカ株式会社製、ＢＥＴ比表面積２４０ｍ２／ｇ）
※１２：Ｎ－シクロヘキシル－２－ベンゾチアゾリルスルフェンアミド
※１３：ノクセラー　ＴＯＴ－Ｎ（大内新興化学工業株式会社製）テトラキス（２－エチルヘキシル）チウラムジスルフィド
Figure JPOXMLDOC01-appb-T000003
 * 1: RSS # 3
* 2: # 1500 (manufactured by JSR Corporation)
* 3: BR01 (manufactured by Ube Industries)
* 4: Asahi # 55 (Asahi Carbon Co., Ltd.)
* 5: Asahi # 70 (Asahi Carbon Co., Ltd.)
* 6: Asahi # 80 (Asahi Carbon Co., Ltd.)
* 7: 2-Naphthalenic acid-3-hydroxy (1,3-dimethylbutylidene) hydrazide * 8: 2-Naphthalenic acid-3-hydroxy (1-methylethylidene) hydrazide * 9: Nip seal ER (Tosoh Silica Corporation) Manufactured, BET specific surface area 95 m 2 / g)
* 10: Nip seal AQ (manufactured by Tosoh Silica Co., Ltd., BET specific surface area 205 m 2 / g)
* 11: Nip seal KQ (Tosoh Silica Co., Ltd., BET specific surface area 240 m 2 / g)
* 12: N-cyclohexyl-2-benzothiazolylsulfenamide * 13: Noxeller TOT-N (Ouchi Shinsei Chemical Co., Ltd.) tetrakis (2-ethylhexyl) thiuram disulfide
　上記表１～３より、本発明のゴム組成物は、低発熱性と耐亀裂進展性とを両立できていることがわかる。 From Tables 1 to 3 above, it can be seen that the rubber composition of the present invention can achieve both low heat buildup and crack growth resistance.
　１　ビード部
　２　サイドウォール部
　３　トレッド部
　４　ビードコア
　５　カーカス
　６　ベルト
　７　ビードフィラー
　８　ベルトエンドゴム
　９　端クッションゴム
　１０　軟スティフナー
　１１　サイドウォールフィラー
　２０　タイヤ DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Bead core 5 Carcass 6 Belt 7 Bead filler 8 Belt end rubber 9 End cushion rubber 10 Soft stiffener 11 Side wall filler 20 Tire

Claims (6)

  1. 　ゴム成分に対して、シリカと、チウラム化合物と、ヒドラジド化合物と、が配合されてなることを特徴とするタイヤの内層部材用ゴム組成物。 A rubber composition for an inner layer member of a tire, wherein silica, a thiuram compound, and a hydrazide compound are blended with a rubber component.
  2. 　前記ゴム成分１００質量部に対して、前記シリカが５～５０質量部、前記チウラム化合物が０．１～２．０質量部、前記ヒドラジド化合物が０．１～５．０質量部である請求項１記載のタイヤの内層部材用ゴム組成物。 The silica is 5 to 50 parts by mass, the thiuram compound is 0.1 to 2.0 parts by mass, and the hydrazide compound is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition for an inner layer member of a tire according to 1.
  3. 　前記シリカの窒素吸着比表面積が２２０ｍ２／ｇ以上である請求項１または２記載のタイヤの内層部材用ゴム組成物。 The rubber composition for an inner layer member of a tire according to claim 1 or 2, wherein the silica has a nitrogen adsorption specific surface area of 220 m 2 / g or more.
  4. 　さらに、カーボンブラックが配合されてなる請求項１～３のうちいずれか一項記載のタイヤの内層部材用ゴム組成物。 The rubber composition for a tire inner layer member according to any one of claims 1 to 3, further comprising carbon black.
  5. 　請求項１～４のうちいずれか一項記載のタイヤの内層部材用ゴム組成物が、ゴム以外の内層部材に接しない内層部材に用いられてなることを特徴とする重荷重用空気入りタイヤ。 5. A heavy-duty pneumatic tire, wherein the rubber composition for an inner layer member of a tire according to any one of claims 1 to 4 is used for an inner layer member that does not contact an inner layer member other than rubber.
  6. 　トレッド部のゲージ厚が７０ｍｍ以上である請求項５記載の重荷重用空気入りタイヤ。 The heavy duty pneumatic tire according to claim 5, wherein the gauge thickness of the tread portion is 70 mm or more.
PCT/JP2018/015886 2017-04-18 2018-04-17 Rubber composition for inner-layer member of tire, and heavy-duty pneumatic tire obtained using same WO2018194063A1 (en)

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08192608A (en) * 1995-01-17 1996-07-30 Bridgestone Corp Bead structure for pneumatic tire
JP2007023070A (en) * 2005-07-12 2007-02-01 Bridgestone Corp Pneumatic radial tire for high-speed and high-load running
JP2009001682A (en) * 2007-06-21 2009-01-08 Sumitomo Rubber Ind Ltd Rubber composition for side reinforcing layer, and run flat tire using the same
JP2009101920A (en) * 2007-10-24 2009-05-14 Bridgestone Corp Tire
JP2010285472A (en) * 2009-06-09 2010-12-24 Bridgestone Corp Pneumatic tire
WO2014148453A1 (en) * 2013-03-22 2014-09-25 株式会社ブリヂストン Rubber composition for tires and pneumatic tire
JP2015025093A (en) * 2013-07-29 2015-02-05 東洋ゴム工業株式会社 Method for producing rubber composition
JP2015083639A (en) * 2013-10-25 2015-04-30 東洋ゴム工業株式会社 Rubber composition
JP2015093879A (en) * 2013-11-08 2015-05-18 東洋ゴム工業株式会社 Method for producing rubber composition
JP2016041779A (en) * 2014-08-15 2016-03-31 株式会社ブリヂストン Tire rubber composition and tire
WO2016056219A1 (en) * 2014-10-07 2016-04-14 株式会社ブリヂストン Rubber composition for conveyor belts, and conveyor belt

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08192608A (en) * 1995-01-17 1996-07-30 Bridgestone Corp Bead structure for pneumatic tire
JP2007023070A (en) * 2005-07-12 2007-02-01 Bridgestone Corp Pneumatic radial tire for high-speed and high-load running
JP2009001682A (en) * 2007-06-21 2009-01-08 Sumitomo Rubber Ind Ltd Rubber composition for side reinforcing layer, and run flat tire using the same
JP2009101920A (en) * 2007-10-24 2009-05-14 Bridgestone Corp Tire
JP2010285472A (en) * 2009-06-09 2010-12-24 Bridgestone Corp Pneumatic tire
WO2014148453A1 (en) * 2013-03-22 2014-09-25 株式会社ブリヂストン Rubber composition for tires and pneumatic tire
JP2015025093A (en) * 2013-07-29 2015-02-05 東洋ゴム工業株式会社 Method for producing rubber composition
JP2015083639A (en) * 2013-10-25 2015-04-30 東洋ゴム工業株式会社 Rubber composition
JP2015093879A (en) * 2013-11-08 2015-05-18 東洋ゴム工業株式会社 Method for producing rubber composition
JP2016041779A (en) * 2014-08-15 2016-03-31 株式会社ブリヂストン Tire rubber composition and tire
WO2016056219A1 (en) * 2014-10-07 2016-04-14 株式会社ブリヂストン Rubber composition for conveyor belts, and conveyor belt

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