JP3676545B2 - Rubber composition and heavy duty pneumatic tire using the same - Google Patents
Rubber composition and heavy duty pneumatic tire using the same Download PDFInfo
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- JP3676545B2 JP3676545B2 JP21764297A JP21764297A JP3676545B2 JP 3676545 B2 JP3676545 B2 JP 3676545B2 JP 21764297 A JP21764297 A JP 21764297A JP 21764297 A JP21764297 A JP 21764297A JP 3676545 B2 JP3676545 B2 JP 3676545B2
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- 229920001971 elastomer Polymers 0.000 title claims description 63
- 239000005060 rubber Substances 0.000 title claims description 63
- 239000000203 mixture Substances 0.000 title claims description 41
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 93
- 239000000377 silicon dioxide Substances 0.000 claims description 46
- 239000006229 carbon black Substances 0.000 claims description 23
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 claims description 22
- 244000043261 Hevea brasiliensis Species 0.000 claims description 15
- 229920003052 natural elastomer Polymers 0.000 claims description 15
- 229920001194 natural rubber Polymers 0.000 claims description 15
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 13
- 238000002156 mixing Methods 0.000 claims description 11
- -1 tertiary amine compound Chemical class 0.000 claims description 11
- 125000004432 carbon atom Chemical group C* 0.000 claims description 9
- 238000010521 absorption reaction Methods 0.000 claims description 8
- 125000004434 sulfur atom Chemical group 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 7
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 7
- 150000008117 polysulfides Polymers 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 229920003244 diene elastomer Polymers 0.000 claims description 5
- NAPSCFZYZVSQHF-UHFFFAOYSA-N dimantine Chemical compound CCCCCCCCCCCCCCCCCCN(C)C NAPSCFZYZVSQHF-UHFFFAOYSA-N 0.000 claims description 4
- 229950010007 dimantine Drugs 0.000 claims description 4
- 125000003342 alkenyl group Chemical group 0.000 claims description 3
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 claims description 3
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000001179 sorption measurement Methods 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 description 23
- 239000005062 Polybutadiene Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 239000006185 dispersion Substances 0.000 description 7
- 230000020169 heat generation Effects 0.000 description 7
- 229920002857 polybutadiene Polymers 0.000 description 7
- 238000005336 cracking Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000000945 filler Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 239000007822 coupling agent Substances 0.000 description 4
- 238000004898 kneading Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000003014 reinforcing effect Effects 0.000 description 4
- 239000012763 reinforcing filler Substances 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 238000013329 compounding Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 230000002787 reinforcement Effects 0.000 description 2
- HYHCSLBZRBJJCH-UHFFFAOYSA-N sodium polysulfide Chemical compound [Na+].S HYHCSLBZRBJJCH-UHFFFAOYSA-N 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 150000003512 tertiary amines Chemical class 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000006237 Intermediate SAF Substances 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- 244000269722 Thea sinensis Species 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 230000003712 anti-aging effect Effects 0.000 description 1
- 229920003193 cis-1,4-polybutadiene polymer Polymers 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000007720 emulsion polymerization reaction Methods 0.000 description 1
- 125000001301 ethoxy group Chemical group [H]C([H])([H])C([H])([H])O* 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 125000004051 hexyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
- 229920003049 isoprene rubber Polymers 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- YWWNNLPSZSEZNZ-UHFFFAOYSA-N n,n-dimethyldecan-1-amine Chemical compound CCCCCCCCCCN(C)C YWWNNLPSZSEZNZ-UHFFFAOYSA-N 0.000 description 1
- XLQINSOTYAWFOG-UHFFFAOYSA-N n,n-dimethylhexadec-1-en-1-amine Chemical compound CCCCCCCCCCCCCCC=CN(C)C XLQINSOTYAWFOG-UHFFFAOYSA-N 0.000 description 1
- HPKDERDMYRXMGT-UHFFFAOYSA-N n,n-dimethyloctadec-1-en-1-amine Chemical compound CCCCCCCCCCCCCCCCC=CN(C)C HPKDERDMYRXMGT-UHFFFAOYSA-N 0.000 description 1
- SFBHPFQSSDCYSL-UHFFFAOYSA-N n,n-dimethyltetradecan-1-amine Chemical compound CCCCCCCCCCCCCCN(C)C SFBHPFQSSDCYSL-UHFFFAOYSA-N 0.000 description 1
- XTAZYLNFDRKIHJ-UHFFFAOYSA-N n,n-dioctyloctan-1-amine Chemical compound CCCCCCCCN(CCCCCCCC)CCCCCCCC XTAZYLNFDRKIHJ-UHFFFAOYSA-N 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- UWHRNIXHZAWBMF-UHFFFAOYSA-N n-dodecyl-n-methyldodecan-1-amine Chemical compound CCCCCCCCCCCCN(C)CCCCCCCCCCCC UWHRNIXHZAWBMF-UHFFFAOYSA-N 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 125000001147 pentyl group Chemical group C(CCCC)* 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920001021 polysulfide Polymers 0.000 description 1
- 239000005077 polysulfide Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 125000002572 propoxy group Chemical group [*]OC([H])([H])C(C([H])([H])[H])([H])[H] 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000000999 tert-butyl group Chemical group [H]C([H])([H])C(*)(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- SWZDQOUHBYYPJD-UHFFFAOYSA-N tridodecylamine Chemical compound CCCCCCCCCCCCN(CCCCCCCCCCCC)CCCCCCCCCCCC SWZDQOUHBYYPJD-UHFFFAOYSA-N 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
Landscapes
- Tires In General (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明はゴム組成物及びそれを用いた重荷重用空気入りタイヤに係り、詳しくは低転がり抵抗性すなわち低発熱性、かつ耐摩耗性、耐テア・クラック性に優れたゴム組成物及びそれを用いた重荷重用空気入りタイヤに関する。
【０００２】
【従来の技術】
地球の温暖化、エネルギーの有効利用の観点から、車輛には燃量性向上が求められ、それに応えるため、タイヤには低転がり抵抗性（低発熱性）が要求されている。同時に、地球環境保全の立場からも、資源の有効活用、リサイクル率の向上を図る上でも、タイヤにはライフ（耐久性）向上が強く要請されている。タイヤのライフ向上は耐摩耗性要因、と乗用車用タイヤに比べて、使用条件が厳しい重荷重用であるトラック、バス用タイヤでは耐テア・クラック性要因に支配され、両支配要因により大きく左右される。つまり、重荷重用空気入りタイヤは低転がり抵抗性とライフ（耐摩耗性、耐テア・クラック性）向上の両立が要求される。
【０００３】
しかし、従来、トレッドゴムの低転がり抵抗性を満足すれば、耐摩耗性、耐テア・クラック性が劣り、耐摩耗性、耐テア・クラック性を向上すると低転がり抵抗性が満たされず、両特性には二律背反の関係のあることがよく知られており、両特性を両立させることは容易ではない。
【０００４】
一方、タイヤトレッド用の各種ゴム組成物が検討されており、例えば、キャップ／ベース構造のタイヤトレッド用ゴム組成物において、キャップ及びベースの二層構造別に、ゴム成分として、所定量の天然ゴム等のジエン系ゴム、と充填剤として所定量の特定のシリカ及びカーボンブラック、通常のシランカップリング剤を用いることにより、走行中の発熱を抑え、耐摩耗性を維持したタイヤが得られるという提案等が知られている。
【０００５】
しかし、シリカとカーボンブラックを併用し、通常のシランカップリング剤を用いることにより、低発熱性（通常、使用されているカーボンブラック系に比べて１０〜２０％発熱性が抑えられる）、と破断伸び増大による耐テア・クラック性は向上するが耐摩耗性は通常のカーボンブラック系に比べて５〜１０％低下し、十分とは言えない。
【０００６】
また、シリカを配合するにあたっては、その小粒径のため、ゴム中での分散確保が難しい。このためシリカ配合系はバンバリー練り負荷量が大きくなり、ゴム組成物製造時の消費電力が大きくなり、エコロジーの観点から好ましくない上、製造コトもかさむため、汎用タイヤへの展開も難しくなっているのが実状である。
【０００７】
【発明が解決しようとする課題】
本発明は上記事実に鑑みてなされたもので、本発明の目的は低転がり抵抗性（低発熱性）と耐摩耗性、耐テア・クラック性を高度に両立したゴム組成物及びそれを用いた重荷重用空気入りタイヤを提供することである。
【０００８】
【課題を解決するための手段】
本発明者は、タイヤトレッドのゴム組成物に着目し、鋭意検討の結果、下記の手段によって、課題が解決できることを見出し、本発明を完成するに至った。
【０００９】
すなわち、（１）本発明のゴム組成物は、天然ゴム１０〜１００重量部及び他のジエン系ゴム９０〜０重量部からなるゴム成分１００重量部に対して、カーボンブラックとシリカの合計量４０〜５５重量部を含み、この合計量のうち、シリカの量が５〜２５重量部であり、かつカーボンブラック量／シリカ量の混合比が１以上であり、該カーボンブラックが窒素吸着比表面積（Ｎ2 ＳＡ）７０〜１７０ｍ2 ／ｇ、かつジブチルフタレート（ＤＢＰ）吸油量１００〜２００ｃｍ3 ／１００ｇの特性を有し、該シリカがＮ2 ＳＡ１２０〜２４０ｍ2 ／ｇ、かつＤＢＰ吸油量１７０〜２５０ｃｍ3 ／１００ｇの特性を有し、かつ下記一般式（Ｉ）で表されるシランカップリング剤をシリカ量の３〜３０重量％、好ましくは５〜１５重量％を含有するトレッドゴムからなることを特徴とする。
【００１０】
【化３】
（式中、ｎは１〜３の整数、ｍは１〜９の整数、ｙはポリサルファイド部の硫黄原子の平均数であり、２．０＜ｙ≦３．５、好ましくは２．５≦ｙ≦３の正数を表す）
（２）前（１）項において、前記天然ゴムが技術的格付天然ゴム（ＴＳＲ）を天然ゴム１００重量％中に３０重量％以上含むことが好ましい。
【００１２】
（３）前（１）項において、前記ゴム組成物が、さらに下記一般式（II）で表される３級アミン化合物をシリカ量に対して０．１〜２０重量％含むことが好ましい。
【００１３】
【化４】
（式中、Ｒ1 、Ｒ2 及びＲ3 はそれぞれ独立にメチル基、炭素数８〜３６のアルキル基、炭素数８〜３６のアルケニル基、シクロヘキシル基又はベンジル基を表す）
（４）前（３）項において、前（３）項に記載の一般式（II）中のＲ1 、Ｒ2 がメチル基で、Ｒ3 が炭素数１２〜３６のアルキル基であることが好ましい。
（５）前（３）項において、前記３級アミン化合物がジメチルステアリルアミンであることが好ましい。
（６）前（１）〜（５）項のいずれか１項に記載のゴム組成物がトレッドゴムとして用いられた重荷重用空気入りタイヤ。
【００１５】
本発明の重荷重用タイヤのゴム組成物は、上記のように、ゴム成分の種類、量を特定し、補強充填剤のカーボンブラックとシリカの各特性、合計量、各配合量（混合比率）を特定し、特にシランカップリング剤の種類、量を特定し、必要に応じて、シリカの分散改良剤として特定の３級アミン化合物を使用することに大きな特徴がある。
【００１６】
本発明のゴム組成物ではゴム成分を天然ゴム主体とし、ブタジエンゴムを適量用いることにより、低転がり抵抗性、耐摩耗性、耐テア・クラック性を高レベルでバランスをとり、また好ましくはＴＳＲを用いることにより、さらに必要に応じて、特定の３級アミンを使用することによりシリカのゴム中の分散性を向上し、低転がり抵抗性（低発熱性）、耐テア・クラック性を一層改良し、カーボンブラックとシリカの各特性の特定化により、補強性維持による耐摩耗性が確保され、破断伸び維持による耐テア・クラック性が高度に維持され、両補強充填剤の合計量の特定化により、耐摩耗性が維持され、破断伸び維持による耐テア・クラック性が確保され、さらに低発熱性（低転がり抵抗性）も維持され、また両補強充填剤の各配合量（混合比率）の特定化により、低発熱性、破断伸び、耐摩耗性の低下が抑えられ、さらに特に特定のシランカップリング剤の使用により、耐摩耗性が改良され、低発熱性も一層改善される。
【００１７】
以上のように、ゴム組成物を適正化することにより課題が解決できるという新知見を得るに至り、ここに低転がり抵抗性と耐摩耗性、耐テア・クラック性を同時に、高度に満足するゴム組成物及びそれを用いた重荷重用空気入りタイヤが得られたものである。
【００１８】
【発明の実施の形態】
本発明に用いられるゴム成分は、全ゴム成分１００重量部中に天然ゴム（ＮＲ）１０〜１００重量部、好ましくは４０〜１００重量部、他のジエン系ゴム９０〜０重量部、好ましくは６０〜０重量部が用いられる。他のジエン系ゴムとしては合成イソプレンゴム、高シス１，４−ポリブタジエン等のブタジエンゴム（ＢＲ）、乳化重合スチレンブタジエンゴム（ＳＢＲ）、溶液重合ＳＢＲ等のＳＢＲ等を挙げることができる。中でもＢＲが好ましく用いられる。ＮＲとＢＲのブレンド系を用いる場合、ＮＲ／ＢＲの混合比は１００／０〜４０／６０が好ましく、８０／２０〜５０／５０がより好ましい。ＮＲが全ブレンド成分１００重量部に対して、４０重量部未満では耐テア・クラック性が劣り、ＢＲが６０重量部を越えると耐摩耗性、低発熱性は改善されるがＮＲの伸長結晶性による耐テア・クラック性のメリットが失われる。天然ゴムとしては各種の天然ゴムが用いられ、例えばＲＳＳ３号等のシートゴム、技術的格付けゴム（ＴＳＲ）等が挙げられる。中でも、シリカの分散性向上の観点からＴＳＲが好ましく用いられ、ＴＳＲが使用される場合、ＴＳＲの配合量は天然ゴム１００重量％中に３０重量％以上、好ましくは６０重量％以上である。３０重量％未満ではシリカの分散不良が起こり、耐テア・クラック性が低下する。
【００１９】
ゴム成分として、天然ゴム単味が用いられる場合、ＴＳＲの配合量は天然ゴム１００重量部中に、５０〜１００重量部が好ましい。
【００２０】
本発明のゴム組成物に用いられるカーボンブラックは窒素吸着比表面積（Ｎ2 ＳＡ）が７０〜１７０ｍ2 ／ｇ、かつジブチルフタレート（ＤＢＰ）吸油量が１００〜２００ｃｍ3 ／１００ｇの特性を有するものが用いられる。Ｎ2 ＳＡが７０ｍ2 ／ｇ未満では補強性が不足し、耐摩耗性が不十分となり、１７０ｍ2 ／ｇを越えるとゴム中の分散が低下し、好ましくない。また、ＤＢＰ吸油量が１００ｃｍ3 ／１００ｇ未満では補強性が不足し、耐摩耗性が十分でなく、２００ｃｍ3 ／１００ｇを越えると破断伸びが低下し、耐テア・クラック性が不良となり、好ましくない。このカーボンブラックとしては、例えば上記特性を満足するＩＳＡＦ、ＳＡＦ等を挙げることができる。
【００２１】
本発明のゴム組成物に用いられるシリカはＮ2 ＳＡが１２０〜２４０ｍ2 ／ｇ、好ましくは１６０〜２００ｍ2 ／ｇ、かつＤＢＰ吸油量が１７０〜２５０ｃｍ3 ／１００ｇ、好ましくは１７０〜２２０ｃｍ3 ／１００ｇの特性を有するものが使用される。Ｎ2 ＳＡが１２０ｍ2 ／ｇ未満では補強性が十分でなく、耐摩耗性に劣り、２４０ｍ2 ／ｇを越えるとゴム中の分散が低下し、好ましくない。ＤＢＰ吸油量が１７０ｃｍ3 ／１００ｇ未満では補強性が不良となり、耐摩耗性が低下し、２５０ｃｍ3 ／１００ｇを越えると破断伸びが低下し、耐テア・クラック性が不良となり、好ましくない。
【００２２】
シリカとしては、沈降法による合成シリカが用いられ、具体的には、日本シリカ工業（株）製のニップシールＡＱ、ドイツデグサ社製のＵＬＴＲＡＳＩＬ ＶＮ３、ＢＶ３３７０ＧＲ、ローヌ・プーラン社製のＲＰ１１６５ＭＰ、Ｚｅｏｓｉｌ１６５ＧＲ、Ｚｅｏｓｉｌ １７５ＶＰ、ＰＰＧ社製のＨｉｓｉｌ ２３３、Ｈｉｓｉｌ ２１０、Ｈｉｓｉｌ ２５５等（いずれも商品名）が挙げられるが上記特性を満足するものであればよく、特に限定するものではない。
【００２３】
本発明に用いられる充填剤は上記のような、カーボンブラック及びシリカからなる。カーボンブラックとシリカの合計配合量はゴム成分１００重量部に対して、４０〜５５重量部であり、この合計量のうち、シリカが５〜２５重量部であり、かつカーボンブラック量／シリカ量の混合比は１以上である。合計量が４０重量部未満では耐摩耗性が低下し、５５重量部を越えると、補強充填剤の分散不良が起こるため耐摩耗性、破断伸び（耐テア・クラック性）が低下すると共に、低発熱性すなわち低転がり抵抗性が悪化するので、好ましくない。またシリカの量が少なすぎるとシリカ配合系の低発熱性（低転がり抵抗性）、破断伸び（耐テア・クラック性）というメリットが十分生かされない。シリカの量が多すぎるとゴム中での分散不良が生じ、上記メリットが発揮できなくなる。カーボンブラック量／シリカ量の混合比が１未満すなわち全充填剤中のシリカ比率が５０％を越えると、本来シリカ系は耐摩耗性不良となるデメリットを有するがさらに耐摩耗性の悪化を招く。
【００２４】
本発明に用いられるカップリング剤はシリカ−ゴム成分間の物理結合がカーボンブラック−ゴム成分間の結合に比べ弱いため、タイヤの耐摩耗性が低下するので、このシリカ−ゴム成分間の結合を強化し、耐摩耗性を確保するために使用される。
【００２５】
本発明において、カップリング剤は前記一般式（Ｉ）で表されるシランカップリング剤が用いられる。式中、ｎは１〜３の整数、ｍは１〜９の整数、好ましくは２〜５の整数を表す。
【００２６】
またポリサルファイド部Ｓｙのｙは硫黄原子の平均数を表し、２．０＜ｙ≦３．５を満足する正数、好ましくは２．５≦ｙ≦３を満足する正数である。硫黄原子の平均数とは該ポリサルファイド部はＳ1 〜Ｓ9 のような異なる硫黄原子数の分布を有するので、この分布の平均の数を意味する。硫黄原子の平均数ｙが２以下すなわちＳ1 、Ｓ2 ではカップリング作用を示さないので補強性が悪化し、ｙが３．５を越えると１５０℃以上の高温練りにおいて、ゴム成分のゲル化が起こり易くなり、ムーニー粘度が大幅に上昇して、生産性が劣ることになる。
【００２７】
シランカップリング剤としては、例えば一般式（Ｉ）のビス（トリアルコキシシリルアルキル）ポリサルファイドのアルコキシ基が例えばメトキシ基、エトキシ基、プロポキシ基；アルキル基が例えばメチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｔ−ブチル基、ペンチル基、ヘキシル基；ポリサルファイド基−Ｓｙ−が上記硫黄原子の平均数を有する基である化合物等が用いられる。
【００２８】
本発明に用いられるシランカップリング剤の製法は特に制限されないが、例えば特開平７−２２８５８８号公報記載の方法などに準拠し次のように製造することができる。
【００２９】
無水硫化ナトリウム（Ｎａ2 Ｓ）と硫黄（Ｓ）とを不活性ガス雰囲気下、極性溶媒中で適切なモル比例えば１：１〜１：３の範囲で反応させて多硫化ナトリウムを得、次いでこの多硫化ナトリウムをハロゲノアルコキシシランを加えて不活性ガス雰囲気下で反応させて得られる。
【００３０】
本発明で用いられるカップリング剤の配合量はシリカ量に対して、３〜３０重量％、好ましくは５〜１５重量％である。３重量％未満では耐摩耗性が低下し、３０重量％を越えると効果のさらなる向上は認められず、経済的な観点からもこれ以上の増量は必要がない。
【００３１】
シリカと通常のシランカップリング剤からなる充填剤は通常のカーボンブラックをシリカと同量で使用する場合に比べて、破断伸びによる耐テア・クラック性、低発熱による低転がり抵抗性で１０〜２０％のメリットがあるが一方耐摩耗性が５〜１０％低下する。しかし、本発明では、特定のシランカップリング剤の使用により、耐摩耗性が高度に維持される。この予想外の効果は本発明の大きな特徴の一つである。
【００３２】
本発明に用いることができる３級アミンは特に充填剤シリカの分散向上の役割を有し、低転がり抵抗性、耐摩耗性の改良とともに、特にタイヤ走行時の発熱を抑えることによって、トレッドゴムの硬化を抑制し、破断伸びを高度に維持し、耐テア・クラック性を改良する。
【００３３】
３級アミン化合物としては、前記一般式（II）中のＲ1 、Ｒ2 、Ｒ3 が、それぞれ独立にメチル基、炭素数８〜３６のアルキル基、炭素数８〜３６のアルケニル基、シクロヘキシル基又はベンジル基である化合物を挙げることができる。具体的には、トリオクチルアミン、トリラウリルアミン、ジメチルステアリルアミン、ジメチルデシルアミン、ジメチルミリスチルアミン、ジラウリルモノメチルアミン、ジメチルオクタデセニルアミン、ジメチルヘキサデセニルアミンなどが好ましく挙げられる。より好ましくは、Ｒ1 、Ｒ2 がメチル基で、Ｒ3 が炭素数１２〜３６のアルキル基である３級アミン化合物であり、更に好ましくは、引火点と低発熱性、充填剤の分散改良の面からジメチルステアリルアミンである。
【００３４】
また、本発明で用いる３級アミン化合物の分子量は、１８０以上であることが好ましい。３級アミン化合物の分子量が１８０より低いと引火点が１００℃以下となり、加工工程で発火の恐れがあり、好ましくない。
【００３５】
上記３級アミン化合物の配合量は、シリカ量に対して０．１〜２０重量％、好ましくは、効果の点から０．５〜４重量％である。
【００３６】
本発明の重荷重用空気入りタイヤのゴム組成物として前記諸成分と共に通常ゴム工業で用いられる、酸化亜鉛、ステアリン酸、老化防止剤、ＷＡＸ、加硫剤等の成分を本発明の効果を損なわない範囲において適宜配合することができる。
【００３７】
加硫剤としては、硫黄等が挙げられ、この使用量は、ゴム成分１００重量部に対して硫黄分として０．１〜５重量部、好ましくは１〜２重量部である。０．１重量部未満では加硫ゴムの破壊強度、耐摩耗性が低下し、５重量部を越えるとゴム弾性が損なわれる傾向がある。
【００３８】
本発明の空気入りタイヤ用ゴム組成物は、ロール、インターナルミキサー、バンバリーミキサー等の混練機を用いて混練りすることによって得られ、成形加工後、加硫を行い、タイヤトレッド等に用いられる。
【００３９】
【実施例】
以下に実施例を挙げて、本発明をより具体的に説明するが、本発明の主旨を越えない限り、本実施例に限定されるものではない。
【００４０】
各種の測定は下記の方法によった。
（１）耐摩耗性
平均接地圧が０．８ＭＰａで使用されるサイズＴＢＲ１１Ｒ２２．５、リブパターンの試作タイヤを１０トントラック全輪に装着し、５万ｋｍ走行後、トレッドゴムのパターンの残溝深さから摩耗量を測定し、その逆数を用いて、従来例１の値を１００とした指数で表示した。従って、数値が大きいほど、耐摩耗性が良好であることを表す。
【００４１】
（２）耐テア・クラック性
試作タイヤを１０トントラック全輪に装着し、５万ｋｍ走行後のタイヤを縁石に対して４５°の角度で乗り上げて、リブ引裂・亀裂の発生具合（引裂・亀裂の長さ）を測定し、その逆数を用いて、従来例１の値を１００とした指数で表示した。従って、数値が大きいほど、耐テア・クラック性が良好であることを表す。
（３）転がり抵抗性
試作タイヤをドラム試験にて、８０ｋｍ／時の走行時のタイヤ接地面に発生する進行方向に対する抵抗を測定し、従来例１の値を１００として指数表示した。数値は大きい程、低転がり抵抗性は良好である。
【００４２】
なお、タイヤ性能の総合評価の目安として、Ｅ転がり抵抗性指数、Ｆ耐摩耗性指数、Ｇ耐テア・クラック性指数のＥ−Ｆ、Ｅ−Ｇの算術平均を算出した。いずれも平均値が大きい程、タイヤ性能は良好である。
【００４３】
（実施例１〜８、従来例１〜２、比較例１〜５）
下記の表１〜４に示す配合処方に従って、混練配合を行い、このトレッドゴム組成物を用いて、タイヤ構造として４スチールベルト、１スチールカーカス、リブパターンの平均接地圧が０．８ＭＰａで使用されるサイズＴＢＲ１１Ｒ２２．５のタイヤを試作し、タイヤの諸特性を測定した。結果を表１〜４に示す。
【００４４】
【表１】
【表２】
【表３】
【表４】
表１〜４に示されるように、本発明のゴム組成物及びそれを用いた重荷重用空気入りタイヤは、低転がり抵抗性と耐摩耗性、耐テア・クラック性を高度に両立した優れた特性を有する。
【００４９】
カーボンブラックとシリカの合計量が本発明に係る範囲を越える場合（従来例１、２，比較例１）は、低転がり抵抗性及び耐テア・クラック性が悪化し、カーボンブラックとシリカの合計量が本発明に係る範囲より少ない場合（比較例２）、カーボンブラック量／シリカ量の混合比が本発明に係る範囲より小さい場合（比較例３）はいずれも耐摩耗性及び耐テア・クラック性が不良となり、シリカの特性（Ｎ2 ＳＡ）が本発明に係る範囲を越える場合（比較例４）は低転がり抵抗性が十分でなく、耐テア・クラック性が悪化し、及びカップリング剤を用いない場合（比較例５）はタイヤ性能全般にわたってレベルが低いことがわかる。タイヤ性能の総合評価に相当する転がり抵抗性指数−耐摩耗性指数の平均値及び転がり抵抗性指数−耐テア・クラック性指数の平均値は実施例に比べて、従来例、比較例が大幅に劣っていることがわかる。
【００５０】
【発明の効果】
本発明のゴム組成物及びそれを用いた重荷重用空気入りタイヤは、上記のような構成としたので、低転がり抵抗性と耐摩耗性、耐テア・クラック性が高度に両立するという優れた効果を奏する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber composition and a heavy-duty pneumatic tire using the rubber composition, and more particularly, to a rubber composition excellent in low rolling resistance, that is, low heat generation, wear resistance, tear resistance and crack resistance. The present invention relates to a heavy duty pneumatic tire.
[0002]
[Prior art]
From the viewpoint of global warming and effective use of energy, vehicles are required to have improved fuel efficiency, and tires are required to have low rolling resistance (low heat generation). At the same time, from the standpoint of protecting the global environment, there is a strong demand for improving the life (durability) of tires in order to effectively use resources and improve the recycling rate. The improvement in tire life is a factor of wear resistance, and in tires for trucks and buses, which are used under heavy loads, which are severe in use conditions, it is governed by factors of tear and crack resistance, and is greatly influenced by both factors. . In other words, heavy duty pneumatic tires are required to have both low rolling resistance and improved life (wear resistance, tear / crack resistance).
[0003]
However, conventionally, if the low rolling resistance of the tread rubber is satisfied, the wear resistance and tear / crack resistance are inferior, and if the wear resistance and tear / crack resistance are improved, the low rolling resistance is not satisfied. Is well known to have a trade-off relationship, and it is not easy to achieve both characteristics.
[0004]
On the other hand, various rubber compositions for tire treads have been studied. For example, in a rubber composition for tire treads with a cap / base structure, a predetermined amount of natural rubber or the like as a rubber component for each two-layer structure of the cap and base. A diene rubber, a specific amount of specific silica and carbon black as a filler, and a proposal to obtain a tire that suppresses heat generation during running and maintains wear resistance by using a normal silane coupling agent, etc. It has been known.
[0005]
However, by using silica and carbon black together and using a normal silane coupling agent, low exothermicity (usually 10-20% exothermicity can be suppressed compared to the carbon black type used), and fracture Although the resistance to tearing and cracking due to increased elongation is improved, the wear resistance is 5 to 10% lower than that of a normal carbon black system, which is not sufficient.
[0006]
Further, when blending silica, it is difficult to ensure dispersion in rubber because of its small particle size. For this reason, the silica compound system has a large Banbury kneading load, which increases the power consumption during the production of the rubber composition, which is not preferable from the viewpoint of ecology, and increases manufacturing costs, making it difficult to deploy to general-purpose tires. This is the actual situation.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned facts, and an object of the present invention is to use a rubber composition that has both low rolling resistance (low heat generation), wear resistance, and tear / crack resistance, and a rubber composition thereof. It is to provide a heavy duty pneumatic tire.
[0008]
[Means for Solving the Problems]
The inventor of the present invention pays attention to the rubber composition of the tire tread, and as a result of intensive studies, the inventors have found that the problem can be solved by the following means, and have completed the present invention.
[0009]
That is, (1) The rubber composition of the present invention has a total amount of carbon black and silica of 40 parts by weight with respect to 100 parts by weight of a rubber component comprising 10 to 100 parts by weight of natural rubber and 90 to 0 parts by weight of another diene rubber. The amount of silica is 5 to 25 parts by weight of the total amount, and the carbon black amount / silica amount mixing ratio is 1 or more, and the carbon black has a nitrogen adsorption specific surface area ( N 2 SA) 70~170m 2 / g , and has a characteristic of dibutyl phthalate (DBP) oil absorption of 100~200cm 3 / 100g, the silica is N 2 SA120~240m 2 / g and DBP oil absorption amount 170～250Cm, It has a 3/100 g of characteristics, and a silane coupling agent represented by the following general formula (I) 3 to 30 weight percent silica content, preferably contains from 5 to 15 wt% Characterized by comprising the Reddogomu.
[0010]
[Chemical 3]
(In the formula, n is an integer of 1 to 3, m is an integer of 1 to 9, y is an average number of sulfur atoms in the polysulfide part, and 2.0 <y ≦ 3.5, preferably 2.5 ≦ y. Represents a positive number of ≦ 3)
(2) In the preceding item (1), the natural rubber preferably contains 30% by weight or more of technically rated natural rubber (TSR) in 100% by weight of natural rubber.
[0012]
(3) In the preceding item (1), the rubber composition preferably further contains a tertiary amine compound represented by the following general formula (II) in an amount of 0.1 to 20% by weight based on the amount of silica.
[0013]
[Formula 4]
(Wherein R 1 , R 2 and R 3 each independently represents a methyl group, an alkyl group having 8 to 36 carbon atoms, an alkenyl group having 8 to 36 carbon atoms, a cyclohexyl group or a benzyl group)
(4) In the item (3), R 1 and R 2 in the general formula (II) described in the item (3) are methyl groups, and R 3 is an alkyl group having 12 to 36 carbon atoms. preferable.
(5) In the preceding item (3), the tertiary amine compound is preferably dimethylstearylamine.
(6) A heavy duty pneumatic tire in which the rubber composition according to any one of (1) to (5) is used as a tread rubber.
[0015]
As described above, the rubber composition of the heavy duty tire of the present invention specifies the type and amount of the rubber component, and includes the characteristics, total amount, and blending amount (mixing ratio) of carbon black and silica as the reinforcing filler. In particular, the type and amount of the silane coupling agent are specified, and if necessary, the use of a specific tertiary amine compound as a silica dispersion improver is a major feature.
[0016]
In the rubber composition of the present invention, the rubber component is mainly composed of natural rubber, and by using an appropriate amount of butadiene rubber, a low level of rolling resistance, wear resistance, tear resistance and crack resistance are balanced at a high level, and preferably TSR is set. If necessary, the use of a specific tertiary amine improves the dispersibility of silica in rubber, and further improves low rolling resistance (low heat generation) and tear / crack resistance. By specifying the characteristics of carbon black and silica, the wear resistance by maintaining the reinforcing property is ensured, the tear resistance by maintaining the elongation at break is highly maintained, and by specifying the total amount of both reinforcing fillers , Wear resistance is maintained, tear / crack resistance is ensured by maintaining elongation at break, low heat build-up (low rolling resistance) is also maintained, and each amount of both reinforcing fillers (mixed) Ratio) can suppress low exothermic property, elongation at break, and wear resistance, and in particular, by using a specific silane coupling agent, wear resistance is improved and low exothermic property is further improved. .
[0017]
As described above, we have gained new knowledge that the problem can be solved by optimizing the rubber composition. This is a rubber that satisfies both high rolling resistance, wear resistance, tear resistance and crack resistance at the same time. A composition and a heavy-duty pneumatic tire using the composition are obtained.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The rubber component used in the present invention is 10 to 100 parts by weight, preferably 40 to 100 parts by weight, and other diene rubbers 90 to 0 parts by weight, preferably 60 parts by weight, based on 100 parts by weight of all rubber components. ~ 0 parts by weight are used. Examples of other diene rubbers include synthetic isoprene rubber, butadiene rubber (BR) such as high cis 1,4-polybutadiene, emulsion polymerization styrene butadiene rubber (SBR), SBR such as solution polymerization SBR, and the like. Of these, BR is preferably used. When a blend system of NR and BR is used, the mixing ratio of NR / BR is preferably 100/0 to 40/60, and more preferably 80/20 to 50/50. If the NR is less than 40 parts by weight with respect to 100 parts by weight of all blend components, the tear resistance and crack resistance are inferior. If the BR exceeds 60 parts by weight, the wear resistance and low heat build-up are improved, but the elongation crystallinity of the NR is improved. The merit of tear / crack resistance is lost. Various natural rubbers are used as the natural rubber, and examples thereof include sheet rubber such as RSS No. 3 and technical rating rubber (TSR). Among these, TSR is preferably used from the viewpoint of improving the dispersibility of silica, and when TSR is used, the amount of TSR is 30% by weight or more, preferably 60% by weight or more in 100% by weight of natural rubber. If it is less than 30% by weight, poor dispersion of silica occurs, and the tear / crack resistance decreases.
[0019]
When natural rubber is used as the rubber component, the amount of TSR is preferably 50 to 100 parts by weight in 100 parts by weight of natural rubber.
[0020]
Carbon black used in the rubber composition of the present invention is given nitrogen adsorption specific surface area (N 2 SA) 70~170m 2 / g, and the dibutyl phthalate (DBP) oil absorption has a characteristic of 100~200cm 3 / 100g Used. When N 2 SA is less than 70 m 2 / g, the reinforcing property is insufficient and the wear resistance is insufficient, and when it exceeds 170 m 2 / g, dispersion in the rubber decreases, which is not preferable. Further, DBP oil absorption amount is insufficient reinforcement is less than 100 cm 3/100 g, no wear resistant enough to decrease the elongation at break exceeds 200 cm 3/100 g, anti-tear-cracking resistance becomes poor, undesirable . Examples of the carbon black include ISAF and SAF that satisfy the above characteristics.
[0021]
Silica used in the rubber composition of the present invention is N 2 SA is 120~240m 2 / g, preferably 160~200m 2 / g, and DBP oil absorption 170~250cm 3 / 100g, preferably 170~220cm 3 / Those having a characteristic of 100 g are used. If N 2 SA is less than 120 m 2 / g, the reinforcing property is not sufficient and the wear resistance is inferior, and if it exceeds 240 m 2 / g, dispersion in the rubber decreases, which is not preferable. DBP absorption reinforcement property becomes poor is less than 170cm 3/100 g, abrasion resistance is lowered, and decreases the elongation at break exceeds 250 cm 3/100 g, anti-tear-cracking resistance becomes poor, which is not preferable.
[0022]
As the silica, synthetic silica by precipitation method is used. Specifically, NIPSEAL AQ manufactured by Nippon Silica Kogyo Co., Ltd., ULTRASIL VN3, BV3370GR manufactured by Degussa Germany, RP1165MP, Zeosil165GR, Zeosil 175VP manufactured by Rhône-Poulenc. , Hisil 233, Hisil 210, Hisil 255, etc. (all are trade names) manufactured by PPG, etc. (all are trade names) may be used as long as they satisfy the above characteristics, and are not particularly limited.
[0023]
The filler used in the present invention comprises carbon black and silica as described above. The total compounding amount of carbon black and silica is 40 to 55 parts by weight with respect to 100 parts by weight of the rubber component. Of this total amount, silica is 5 to 25 parts by weight and the amount of carbon black / silica is The mixing ratio is 1 or more. When the total amount is less than 40 parts by weight, the wear resistance is lowered, and when it exceeds 55 parts by weight, the reinforcing filler is poorly dispersed, so that the wear resistance and elongation at break (tear / crack resistance) are lowered. Since exothermicity, that is, low rolling resistance deteriorates, it is not preferable. On the other hand, if the amount of silica is too small, the advantages of the silica compounding system such as low exothermic property (low rolling resistance) and elongation at break (tea / crack resistance) cannot be fully utilized. If the amount of silica is too large, poor dispersion in the rubber will occur, making it impossible to exhibit the above merits. If the mixing ratio of carbon black amount / silica amount is less than 1, that is, the silica ratio in the total filler exceeds 50%, the silica system inherently has the disadvantage of poor wear resistance, but further deteriorates the wear resistance.
[0024]
In the coupling agent used in the present invention, the physical bond between the silica and rubber components is weaker than the bond between the carbon black and rubber components, so that the wear resistance of the tire is reduced. Used to strengthen and ensure wear resistance.
[0025]
In the present invention, the silane coupling agent represented by the general formula ( I ) is used as the coupling agent. In formula, n represents the integer of 1-3, m represents the integer of 1-9, Preferably the integer of 2-5 is represented.
[0026]
Moreover, y of the polysulfide part Sy represents the average number of sulfur atoms, and is a positive number satisfying 2.0 <y ≦ 3.5, preferably a positive number satisfying 2.5 ≦ y ≦ 3. The average number of sulfur atoms means the average number of this distribution because the polysulfide part has a distribution of different numbers of sulfur atoms such as S 1 to S 9 . When the average number y of sulfur atoms is 2 or less, that is, S 1 and S 2 do not exhibit a coupling action, the reinforcing property is deteriorated. When y exceeds 3.5, gelation of the rubber component occurs at high temperature kneading at 150 ° C. or higher. Is likely to occur, the Mooney viscosity is significantly increased, and the productivity is inferior.
[0027]
As the silane coupling agent, for example, the alkoxy group of the bis (trialkoxysilylalkyl) polysulfide of the general formula ( I ) is, for example, methoxy group, ethoxy group, propoxy group; the alkyl group is, for example, methyl group, ethyl group, n-propyl group , An isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group; a compound in which the polysulfide group -Sy- is a group having the above average number of sulfur atoms.
[0028]
Although the manufacturing method of the silane coupling agent used for this invention is not restrict | limited, For example, based on the method of Unexamined-Japanese-Patent No. 7-228588, etc., it can manufacture as follows.
[0029]
Anhydrous sodium sulfide (Na 2 S) and sulfur (S) are reacted in a polar solvent under an inert gas atmosphere in an appropriate molar ratio, eg, 1: 1 to 1: 3 to obtain sodium polysulfide, This sodium polysulfide is obtained by adding halogenoalkoxysilane and reacting under an inert gas atmosphere.
[0030]
The amount of the coupling agent used in the present invention is 3 to 30% by weight, preferably 5 to 15% by weight, based on the amount of silica. If it is less than 3% by weight, the wear resistance is lowered, and if it exceeds 30% by weight, no further improvement in the effect is observed, and no further increase is necessary from an economic point of view.
[0031]
The filler composed of silica and a normal silane coupling agent has a resistance to tear / cracking due to elongation at break and low rolling resistance due to low heat generation, compared with the case where normal carbon black is used in the same amount as silica. %, While the wear resistance is reduced by 5 to 10%. However, in the present invention, wear resistance is highly maintained by the use of a specific silane coupling agent. This unexpected effect is one of the major features of the present invention.
[0032]
The tertiary amine that can be used in the present invention has a role of improving the dispersion of the filler silica in particular, and improves the low rolling resistance and wear resistance, and suppresses heat generation particularly during tire running, thereby reducing the tread rubber. Curing is suppressed, breaking elongation is maintained at a high level, and tear / crack resistance is improved.
[0033]
As the tertiary amine compound, R 1 , R 2 and R 3 in the general formula (II) are each independently a methyl group, an alkyl group having 8 to 36 carbon atoms, an alkenyl group having 8 to 36 carbon atoms, or cyclohexyl. And a compound which is a group or a benzyl group. Specific examples include trioctylamine, trilaurylamine, dimethylstearylamine, dimethyldecylamine, dimethylmyristylamine, dilaurylmonomethylamine, dimethyloctadecenylamine, and dimethylhexadecenylamine. More preferably, it is a tertiary amine compound in which R 1 and R 2 are methyl groups and R 3 is an alkyl group having 12 to 36 carbon atoms, and more preferably, a flash point and low exothermic property, and improved dispersion of fillers. From the aspect of dimethylstearylamine.
[0034]
The molecular weight of the tertiary amine compound used in the present invention is preferably 180 or more. When the molecular weight of the tertiary amine compound is lower than 180, the flash point becomes 100 ° C. or less, which may cause ignition in the processing step, which is not preferable.
[0035]
The amount of the tertiary amine compound is 0.1 to 20% by weight, preferably 0.5 to 4% by weight, based on the effect, based on the amount of silica.
[0036]
Components such as zinc oxide, stearic acid, anti-aging agent, WAX, vulcanizing agent, etc., which are usually used in the rubber industry together with the above components as the rubber composition of the heavy duty pneumatic tire of the present invention, do not impair the effects of the present invention. It can mix | blend suitably in the range.
[0037]
Sulfur etc. are mentioned as a vulcanizing agent, and this usage-amount is 0.1-5 weight part as a sulfur content with respect to 100 weight part of rubber components, Preferably it is 1-2 weight part. If the amount is less than 0.1 part by weight, the fracture strength and wear resistance of the vulcanized rubber are lowered, and if it exceeds 5 parts by weight, rubber elasticity tends to be impaired.
[0038]
The rubber composition for a pneumatic tire of the present invention is obtained by kneading using a kneader such as a roll, an internal mixer, a Banbury mixer, etc., and is vulcanized after molding and used for a tire tread or the like. .
[0039]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples as long as the gist of the present invention is not exceeded.
[0040]
Various measurements were performed by the following methods.
(1) Wear resistance The size TBR11R22.5, which is used at an average contact pressure of 0.8 MPa, and a rib pattern prototype tire is mounted on all 10-ton trucks, and after running 50,000 km, the remaining groove depth of the tread rubber pattern Then, the amount of wear was measured, and the reciprocal thereof was used and displayed as an index with the value of Conventional Example 1 being 100. Therefore, the larger the value, the better the wear resistance.
[0041]
(2) Tear / crack resistance Prototype tires are mounted on all 10-ton trucks, and the tires after running 50,000 km are run at an angle of 45 ° with respect to the curb, causing rib tearing / cracking (tearing / cracking) ) Was measured, and the reciprocal thereof was used to indicate an index with the value of Conventional Example 1 being 100. Therefore, the larger the value, the better the tear / crack resistance.
(3) The resistance against the traveling direction generated on the tire ground contact surface during running at 80 km / hour was measured for a rolling resistance prototype tire in a drum test, and the value of Conventional Example 1 was indicated as 100. The larger the value, the better the rolling resistance.
[0042]
In addition, the arithmetic average of EF and E-G of E rolling resistance index, F abrasion resistance index, and G tear resistance / crack resistance index was calculated as a standard for comprehensive evaluation of tire performance. In any case, the larger the average value, the better the tire performance.
[0043]
(Examples 1-8, Conventional Examples 1-2, Comparative Examples 1-5)
According to the blending formulation shown in Tables 1 to 4 below, kneading blending is performed, and using this tread rubber composition, an average contact pressure of 4 steel belt, 1 steel carcass, and rib pattern is used as a tire structure at 0.8 MPa. A tire having a size of TBR11R22.5 was manufactured and various characteristics of the tire were measured. The results are shown in Tables 1-4.
[0044]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
As shown in Tables 1 to 4, the rubber composition of the present invention and the heavy-duty pneumatic tire using the rubber composition have excellent properties that are both highly compatible with low rolling resistance, wear resistance, and tear / crack resistance. Have
[0049]
When the total amount of carbon black and silica exceeds the range according to the present invention (conventional examples 1, 2 and comparative example 1), the low rolling resistance and tear / crack resistance deteriorate, and the total amount of carbon black and silica. Is less than the range according to the present invention (Comparative Example 2), and when the mixing ratio of the amount of carbon black / silica is smaller than the range according to the present invention (Comparative Example 3), both wear resistance and tear / crack resistance And the characteristics of the silica (N 2 SA) exceed the range according to the present invention (Comparative Example 4), the low rolling resistance is not sufficient, the tear crack resistance is deteriorated, and a coupling agent is used. When not used (Comparative Example 5), it can be seen that the level is low throughout the tire performance. The average value of rolling resistance index-wear resistance index and the average value of rolling resistance index-tear / crack resistance index corresponding to comprehensive evaluation of tire performance are significantly higher in the conventional example and the comparative example than in the examples. It turns out that it is inferior.
[0050]
【The invention's effect】
Since the rubber composition of the present invention and the heavy-duty pneumatic tire using the rubber composition have the above-described configuration, the excellent effect that the low rolling resistance, the wear resistance, and the tear / crack resistance are highly compatible. Play.
Claims (8)
カーボンブラックとシリカの合計量４０〜５５重量部を含み、この合計量のうち、シリカの量が５〜２５重量部であり、かつカーボンブラック量／シリカ量の混合比が１以上であり、
該カーボンブラックが窒素吸着比表面積（Ｎ2 ＳＡ）７０〜１７０ｍ2 ／ｇ、かつジブチルフタレート（ＤＢＰ）吸油量１００〜２００ｃｍ3 ／１００ｇの特性を有し、
該シリカがＮ2 ＳＡ１２０〜２４０ｍ2 ／ｇ、かつＤＢＰ吸油量１７０〜２５０ｃｍ3 ／１００ｇの特性を有し、かつ
下記一般式（Ｉ）で表されるシランカップリング剤をシリカ量の３〜３０重量％、
を含有するトレッドゴムからなることを特徴とするゴム組成物。
Including a total amount of carbon black and silica of 40 to 55 parts by weight, of which the amount of silica is 5 to 25 parts by weight and the carbon black amount / silica amount mixing ratio is 1 or more,
It has the carbon black is a nitrogen adsorption specific surface area (N 2 SA) 70~170m 2 / g, and the properties of dibutyl phthalate (DBP) oil absorption of 100~200cm 3 / 100g,
3-30 the silica is N 2 SA120~240m 2 / g, and has a characteristic of DBP oil absorption of 170~250cm 3 / 100g, and a silane coupling agent represented by the following general formula (I) of the amount of silica weight%,
A rubber composition comprising a tread rubber containing
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| JP21764297A JP3676545B2 (en) | 1997-08-12 | 1997-08-12 | Rubber composition and heavy duty pneumatic tire using the same |
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| Application Number | Priority Date | Filing Date | Title |
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| JP21764297A JP3676545B2 (en) | 1997-08-12 | 1997-08-12 | Rubber composition and heavy duty pneumatic tire using the same |
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| JP3676545B2 true JP3676545B2 (en) | 2005-07-27 |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4916604B2 (en) * | 1999-09-03 | 2012-04-18 | 花王株式会社 | Rubber composition |
| JP4598909B2 (en) * | 1999-12-02 | 2010-12-15 | 株式会社ブリヂストン | Rubber composition and pneumatic tire using the same |
| JP2001214000A (en) * | 2000-02-02 | 2001-08-07 | Bridgestone Corp | Pneumatic tire for heavy load |
| JP4889851B2 (en) * | 2000-11-16 | 2012-03-07 | 株式会社ブリヂストン | Rubber composition for tire and tire |
| KR100445833B1 (en) * | 2001-11-26 | 2004-08-30 | 한국타이어 주식회사 | Radial Tire tread |
| KR20030042882A (en) * | 2001-11-26 | 2003-06-02 | 한국타이어 주식회사 | Tread rubber composition for pneumatic tire |
| CN104262694A (en) * | 2014-08-29 | 2015-01-07 | 朱其贵 | Anti-wear heat-resistant rubber |
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