JP3021801B2 - Pneumatic tire - Google Patents
Pneumatic tireInfo
- Publication number
- JP3021801B2 JP3021801B2 JP3171980A JP17198091A JP3021801B2 JP 3021801 B2 JP3021801 B2 JP 3021801B2 JP 3171980 A JP3171980 A JP 3171980A JP 17198091 A JP17198091 A JP 17198091A JP 3021801 B2 JP3021801 B2 JP 3021801B2
- Authority
- JP
- Japan
- Prior art keywords
- rubber
- tread
- molecular weight
- performance
- tire
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229920001971 elastomer Polymers 0.000 claims description 58
- 239000005060 rubber Substances 0.000 claims description 58
- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 claims description 19
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 8
- 239000011159 matrix material Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 230000006872 improvement Effects 0.000 description 9
- 238000005299 abrasion Methods 0.000 description 4
- 238000005187 foaming Methods 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 230000003014 reinforcing effect Effects 0.000 description 4
- 239000007790 solid phase Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 244000043261 Hevea brasiliensis Species 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229920003052 natural elastomer Polymers 0.000 description 3
- 229920001194 natural rubber Polymers 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 229920002857 polybutadiene Polymers 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000005062 Polybutadiene Substances 0.000 description 2
- 239000003963 antioxidant agent Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- NNBZCPXTIHJBJL-UHFFFAOYSA-N decalin Chemical compound C1CCCC2CCCCC21 NNBZCPXTIHJBJL-UHFFFAOYSA-N 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 238000004073 vulcanization Methods 0.000 description 2
- 239000004705 High-molecular-weight polyethylene Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229920005683 SIBR Polymers 0.000 description 1
- 239000004902 Softening Agent Substances 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 229920005601 base polymer Polymers 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 229920003244 diene elastomer Polymers 0.000 description 1
- 229920001821 foam rubber Polymers 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000010399 physical interaction Effects 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- PXXNTAGJWPJAGM-UHFFFAOYSA-N vertaline Natural products C1C2C=3C=C(OC)C(OC)=CC=3OC(C=C3)=CC=C3CCC(=O)OC1CC1N2CCCC1 PXXNTAGJWPJAGM-UHFFFAOYSA-N 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Landscapes
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Tires In General (AREA)
- Tyre Moulding (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は空気入りタイヤに関し、
詳しくは、夏期における操縦性能および耐久性能を損な
うことなく、氷雪路面上における駆動性、制動性および
操縦性を著しく改良したオールシーズン用空気入りタイ
ヤに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire,
More specifically, the present invention relates to an all-season pneumatic tire having significantly improved driving, braking, and maneuverability on icy and snowy roads without impairing steering performance and durability in summer.
【０００２】[0002]
【従来の技術】近年、冬期においてもタイヤ交換するこ
と無く、夏期と同様に使用できるいわゆるオールシーズ
ンタイヤの需要が高まってきている。このようなタイヤ
は冬期においても夏期と同様のドライグリップ性、ウエ
ットグリップ性、操縦安定性、耐久性、低燃費性を有
し、さらに氷上や雪上においても十分な駆動性や制動性
を有することが要求される。従来、このようなタイヤに
用いられるトレッドゴムには、サマー用トレッドゴムの
低温での硬度を低くすることが要求され、従ってガラス
転移点の低いポリマーを使用するか、もしくは低温での
弾性率を適切に保てる軟化剤や可塑剤を用いる方法が知
られている。2. Description of the Related Art In recent years, demand for so-called all-season tires that can be used in the same manner as in summer without replacing tires in winter has been increasing. Such tires have the same dry grip, wet grip, steering stability, durability, and fuel economy as in the summer as in the summer, and have sufficient driving and braking performance on ice and snow. Is required. Conventionally, tread rubbers used in such tires have been required to reduce the low-temperature hardness of tread rubber for summer, so that a polymer having a low glass transition point should be used or the elastic modulus at a low temperature must be reduced. A method using a softener or a plasticizer that can be appropriately maintained is known.
【０００３】しかし、前者の方法では、かかるポリマー
のヒステリシス特性のために、氷雪温度領域ではそこそ
この性能が発揮されても、湿潤路面や乾燥路面での制動
性や操縦性が十分でないという問題点があり、また後者
の方法も、特開昭55−135149号、特開昭58−199203号、
特開昭60−137945号公報などに開示されているが、いず
れの方法においても、氷雪上性能の改良の程度の割りに
は、一般路を走行した際の耐摩耗性や耐久性に及ぼす悪
影響が大きいなどの問題点が指摘されている。However, in the former method, due to the hysteresis characteristics of the polymer, even if the performance is moderate in an ice and snow temperature range, the braking performance and the maneuverability on wet or dry road surfaces are not sufficient. There is also the latter method, JP-A-55-135149, JP-A-58-199203,
Although disclosed in Japanese Patent Application Laid-Open No. 60-137945, in any of the methods, depending on the degree of improvement in performance on ice and snow, adverse effects on abrasion resistance and durability when traveling on general roads are considered. Have been pointed out.
【０００４】一方、上述した従来のタイヤトレッドに用
いられるゴム組成物は、一般に天然ゴム(NR)、スチレン
‐ブタジエンゴム(SBR) 、ブタジエンゴム(BR)などや、
それらをブレンドしたものがベースポリマーとして選ば
れ、これに粒度の細かい補強性の高いカーボンブラッ
ク、硫黄等の加硫剤、加硫促進剤、他に老化防止剤、軟
化剤などのゴム薬品が加えられた複合材料ではあるが、
これは同時に均質材料であるということもできる。従
来、タイヤトレッドに要求される性能の向上に対して
は、上述のように、かかるゴム組成物を構成するポリマ
ー、カーボンブラック、その他のゴム薬品等の構成因子
について単独で、あるいは複数について相互に関連させ
て改良することで対処する方法が主に採られており、結
果として均質複合材の枠内における改良検討が主体であ
った。[0004] On the other hand, the rubber composition used in the conventional tire tread described above generally includes natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and the like.
A blend of these is selected as the base polymer, to which fine-grained carbon black, a vulcanizing agent such as sulfur, a vulcanization accelerator, and other rubber chemicals such as an antioxidant and a softening agent are added. Composite material,
It can also be said that it is a homogeneous material. Conventionally, as for the improvement in performance required for tire treads, as described above, the constituents of the rubber composition such as the polymer, carbon black, and other rubber chemicals are used alone or mutually for a plurality. The method of coping with the improvement by relating is mainly adopted, and as a result, the improvement examination in the frame of the homogeneous composite material was mainly performed.
【０００５】しかし、こうした均質ゴム組成物による従
来のタイヤ性能の改良手法に代わって、ゴム組成物を不
均一にし、すなわち 0.1〜1000μm 程度の平均粒径範囲
内のドメインをゴム組成物内に形成させて、いわゆる海
島構造を持って不均一構造ゴム組成物とし、このドメイ
ンを形成する材料の性状、充填部数を変化させることに
よって従来の均質系ゴムの枠内でのゴム物性の制御とは
異なったアプローチでタイヤトレッドの性能を改良させ
得ることも知られている。[0005] However, instead of the conventional technique for improving tire performance by the homogeneous rubber composition, the rubber composition is made non-uniform, that is, domains having an average particle size in the range of about 0.1 to 1000 µm are formed in the rubber composition. By changing the properties of the material forming this domain and the number of filled parts, it is different from the control of the physical properties of rubber in the conventional homogeneous rubber frame by forming a so-called sea-island structure with a non-uniform structure rubber composition. It is also known that an improved approach can improve tire tread performance.
【０００６】すなわち、均質系ゴムでの物性改良におい
ては、例えばグリップ性能と耐摩耗性能との間で二律背
反的関係を生じるケースが多く、両方の性能を同時に向
上させるには限界があった。これに対し、海島構造を有
する不均質ゴム組成物では、ドメイン部 (島部) とマト
リックス部 (海部) とで性能向上因子を振り分けて持た
せること等により、こうした問題の解決が図れ得ること
が期待される。That is, in the improvement of physical properties of a homogeneous rubber, for example, there are many cases in which a trade-off relationship occurs between grip performance and wear resistance, and there is a limit in simultaneously improving both performances. In contrast, in the case of a heterogeneous rubber composition having a sea-island structure, it is possible to solve such problems by assigning performance improving factors to the domain part (island part) and the matrix part (sea part). Be expected.
【０００７】しかし、かかる不均質構造ゴム組成物を導
入する場合、ドメイン部とマトリックス部との間に、化
学的または物理的な相互作用が存在し、ドメイン部が補
強性を有しなければ十分に不均質構造のメリットが発現
されず、却ってドメイン部はマトリックス部に対して破
壊核として作用してしまう結果となる。従って、不均質
系ゴムに対する物性制御にはドメイン部の補強性が不可
欠である。しかし、0.1 〜1000μm 程度のドメイン径を
形成し、なおかつマトリックス部に対して十分な補強性
を有する材料についての検討はこれまで殆どなされてい
ないのが現状である。However, when such a heterogeneous structural rubber composition is introduced, a chemical or physical interaction exists between the domain part and the matrix part, and if the domain part has no reinforcing property, it is not sufficient. However, the advantage of the heterogeneous structure is not exhibited, and the domain part acts as a fracture nucleus for the matrix part. Therefore, reinforcement of the domain portion is indispensable for controlling the physical properties of the heterogeneous rubber. However, at present, almost no study has been made on a material having a domain diameter of about 0.1 to 1000 μm and having sufficient reinforcing properties for the matrix portion.
【０００８】更に、近年、トレッドゴムを適当な方法で
発泡させ、独立気泡を生成させる方法がある（特開昭63
-89547号公報) 。即ち、このようにして得られるトレッ
ドゴムの氷面は、多数の気孔で覆われているため、氷面
に対する除水効果及び気孔部のミクロな運動に伴う氷を
削り取るエッジ効果の発現によって、氷上高摩擦性を発
現するものである。しかし、発泡ゴムをトレッドに用い
た場合、必ずしも耐摩耗性等のタイヤ耐久面において満
足なレベルにあるとはいえなかった。Further, in recent years, there has been a method in which a tread rubber is foamed by an appropriate method to generate closed cells (Japanese Patent Laid-Open No. Sho 63/63).
-89547). That is, since the ice surface of the tread rubber thus obtained is covered with a number of pores, a water removal effect on the ice surface and an edge effect of shaving ice accompanying micro-movement of the pores develop on ice. It exhibits high frictional properties. However, when foamed rubber is used for the tread, it cannot be said that the tire durability such as abrasion resistance is always at a satisfactory level.
【０００９】上述のように、従来のいずれの技術を用い
た場合でも、−５℃以下の比較的低温領域（いわゆるド
ライ・オン・アイス）での氷雪上性能と０℃付近の湿潤
状態（いわゆるウエット・オン・アイス）にある氷雪上
性能との両立を図りつつ、充分な摩擦係数を得、かつ駆
動性、制動性及び操縦性を全般的に改良することは極め
て困難なことであった。As described above, in any of the conventional techniques, the performance on ice and snow in a relatively low temperature range of -5 ° C. or less (so-called dry-on-ice) and the wet state near 0 ° C. It has been extremely difficult to obtain a sufficient coefficient of friction and to improve driveability, braking performance and maneuverability in general while achieving compatibility with the performance on ice and snow in wet-on-ice.
【００１０】[0010]
【発明が解決しようとする課題】本発明の目的は、上記
困難を克服し、夏季における操縦性能及び耐久性能を損
なうことなく、氷雪路面上における駆動性、制動性及び
操縦性を改良した空気入りタイヤを提供することであ
り、特に耐摩耗性を低下させることなく、前記のような
湿潤状態にある氷雪路面上での駆動性、制動性及び操縦
性を向上させたタイヤを提供することである。SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned difficulties and to improve the driving performance, braking performance and maneuverability on ice and snow road surfaces without impairing the driving performance and durability in summer. It is an object of the present invention to provide a tire which has improved driving performance, braking performance and maneuverability on the icy and snowy road surface in a wet state as described above, without reducing wear resistance. .
【００１１】[0011]
【課題を解決するための手段】本発明者らは、上記課題
を解決すべく鋭意検討した結果、特定の粒径を有する超
高分子量ポリエチレンが配合され、かつ特定の発泡倍率
を有する発泡ゴムをトレッドに用いることにより、上記
目的を達成し得ることを見い出し、本発明を完成するに
至った。すなわち、本発明の空気入りタイヤは、分子量
50万以上である、平均粒径１〜500 μm の超高分子量ポ
リエチレンをゴム分 100重量部に対し３〜100 重量部含
有し、かつ３〜35％の発泡倍率の独立気泡を有する発泡
ゴムをトレッドに備えたことを特徴とするものである。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a foamed rubber containing a specific high-molecular-weight polyethylene having a specific particle size and having a specific expansion ratio is obtained. It has been found that the above object can be achieved by using the tread, and the present invention has been completed. That is, the pneumatic tire of the present invention has a molecular weight
A foamed rubber containing 500,000 or more ultrahigh molecular weight polyethylene having an average particle diameter of 1 to 500 μm in an amount of 3 to 100 parts by weight based on 100 parts by weight of rubber and having closed cells with an expansion ratio of 3 to 35%. The present invention is characterized in that the tread is provided.
【００１２】本発明において、超高分子量ポリエチレン
の分子量が50万以上とは、デカリン溶媒 135℃における
極限粘度〔η〕が4.5dl/g 以上のことである。但し、好
ましくは 35dl/g 以下とする。超高分子量ポリエチレン
の極限粘度が 35dl/g を超えるものは工業的に生産する
ことが困難となるからである。超高分子量ポリエチレン
粉末は、例えば商品名ハイゼックスミリオン 240Ｍ（登
録商標） (三井石油化学工業（株）製、〔η〕＝ 16.5d
l/g ）や商品名ハイゼックス ミリオン 145Ｍ（登録商
標）（三井化学工業（株）製、〔η〕＝8.20dl/g）とし
て入手可能である。ちなみに、汎用ポリエチレンの極限
粘度 [η] は 2.6 dl/g 程度である。In the present invention, the ultrahigh molecular weight polyethylene having a molecular weight of 500,000 or more means that the intrinsic viscosity [η] at 135 ° C. of a decalin solvent is 4.5 dl / g or more. However, it is preferably 35 dl / g or less. This is because ultrahigh molecular weight polyethylene having an intrinsic viscosity exceeding 35 dl / g is difficult to produce industrially. Ultra high molecular weight polyethylene powder is available, for example, under the trade name Hyzex Million 240M (registered trademark) (manufactured by Mitsui Petrochemical Industries, Ltd., [η] = 16.5d
l / g) and trade name HIZEX Million 145M (registered trademark) ([η] = 8.20 dl / g) manufactured by Mitsui Chemicals, Inc. Incidentally, the intrinsic viscosity [η] of general-purpose polyethylene is about 2.6 dl / g.
【００１３】本発明の空気入りタイヤは、マトリックス
としてのトレッドゴム中に超高分子量ポリエチレンが該
トレッドゴムより硬いドメインを形成することになる。
ドメインとしての超高分子量ポリエチレンとマトリック
スとしてのゴムとは、混練中の超高分子量ポリエチレン
およびゴムからのラジカル発生により化学的に結合して
いると考えられる。従って、本発明の不均質構造のゴム
組成物は、ドメイン部がマトリックス部に対して補強性
を有し、十分に両者が接着した状態を保ち、なおかつド
メイン部がマトリックス部に対してより高い硬度と弾性
率をもつため、かかるゴム組成物を表面に持つゴムは、
ドメイン形成効果として以下の３つの性能向上が可能で
ある。In the pneumatic tire of the present invention, the ultrahigh molecular weight polyethylene forms domains harder than the tread rubber in the tread rubber as a matrix.
It is considered that the ultrahigh molecular weight polyethylene as the domain and the rubber as the matrix are chemically bonded by radical generation from the ultrahigh molecular weight polyethylene and the rubber during kneading. Therefore, the rubber composition having a heterogeneous structure of the present invention has a domain part having a reinforcing property with respect to a matrix part, and a state in which both are sufficiently adhered to each other, and the domain part has a higher hardness than the matrix part. And the elastic modulus, the rubber having such a rubber composition on the surface,
The following three performance improvements are possible as domain formation effects.
【００１４】第１に、かかるドメインの存在によって、
タイヤトレッドの踏面部の外力に対しての動的挙動に変
化を生じ、ドメイン部の硬度・弾性率および充填量を適
当に制御することによってタイヤトレッドの踏面部の耐
摩耗性を向上させることができる。第２に、かかる複合
系ゴム組成物においては、ドメイン部の硬度および弾性
率を上げることによって不均質構造ゴム組成物全体の硬
度と弾性率とを上げることができることが知られている
が、これによってタイヤトレッドの踏面部のパターンに
おけるブロック剛性が高まり、この結果、例えばドライ
状態でのグリップ性能の向上が図れる。第３に、かかる
ドメイン部の存在によって、タイヤトレッドの踏面部の
表面にドメイン径オーダーの表面凹凸が形成され、この
凹凸には上記パターンによって形成される表面溝と同様
に排水効果があるため、タイヤの耐ウエットスキッド性
が向上する。また、こうした排水性とブロック剛性の向
上効果は同時に、氷雪上でのこれら性能の向上も可能と
する。First, due to the existence of such a domain,
A change occurs in the dynamic behavior of the tread portion of the tire tread with respect to external force, and the wear resistance of the tread portion of the tire tread can be improved by appropriately controlling the hardness, elastic modulus and filling amount of the domain portion. it can. Second, in such a composite rubber composition, it is known that the hardness and the elastic modulus of the entire heterogeneous structure rubber composition can be increased by increasing the hardness and the elastic modulus of the domain portion. This increases the block rigidity in the pattern of the tread portion of the tire tread, and as a result, for example, the grip performance in a dry state can be improved. Third, due to the presence of such a domain portion, surface irregularities of the order of the domain diameter are formed on the surface of the tread portion of the tire tread, and since these irregularities have a drainage effect similarly to the surface grooves formed by the pattern, The wet skid resistance of the tire is improved. In addition, the effect of improving the drainage performance and the block rigidity also enables these performances to be improved on ice and snow.
【００１５】かかる超高分子量ポリエチレンの分子量が
50万未満だと、混練時にメルトフローしやすく、不均質
構造を作り得ない場合がある他、ドメイン部を形成した
場合においてもドメイン部の硬度がマトリックスゴム硬
度対比不十分となり、タイヤの各性能に十分な向上効果
がみられないため、好ましくない。また、超高分子量ポ
リエチレンの充填部数が原料ゴム 100重量部に対し３重
量部未満では、ブロック剛性の向上および表面凸凹の形
成がいずれも不十分となるため、とくにグリップ性、耐
ウエットスキッド性の向上が不十分となる。逆に、100
重量部を越えて充填すると、超高分子量ポリエチレンの
補強効果と破壊核としての作用のバランスが崩れ、とり
わけ耐摩耗性能を低下させてしまい、好ましくない。更
に、かかる超高分子量ポリエチレン粒子の平均粒径が１
μm 未満であると、タイヤの前記氷雪性能が充分でな
い。一方、この平均粒径が 500μm を超えると、発泡ゴ
ムを用いたトレッドの耐摩耗性が低下するのでよくな
い。The molecular weight of such ultra-high molecular weight polyethylene is
If it is less than 500,000, it tends to melt flow during kneading and may not be able to form an inhomogeneous structure, and even when a domain portion is formed, the hardness of the domain portion becomes insufficient compared to the matrix rubber hardness, and each tire performance Is not preferable because no sufficient improvement effect is observed. If the number of ultra high molecular weight polyethylene is less than 3 parts by weight per 100 parts by weight of the raw rubber, the improvement of the block rigidity and the formation of the unevenness on the surface are both insufficient. The improvement is insufficient. Conversely, 100
If the filler is added in excess of parts by weight, the balance between the reinforcing effect of ultra-high molecular weight polyethylene and the function as a fracture nucleus is lost, and in particular, the abrasion resistance is reduced, which is not preferable. Further, the average particle size of the ultrahigh molecular weight polyethylene particles is 1
If it is less than μm, the ice and snow performance of the tire is not sufficient. On the other hand, if the average particle size exceeds 500 μm, the wear resistance of the tread using the foamed rubber is deteriorated, which is not good.
【００１６】ゴム成分としては、天然ゴム、ポリイソプ
レンゴム、ポリブタジエンゴム、スチレン−ブタジエン
共重合体ゴム、スチレン−イソプレン−ブタジエン三元
共重合体ゴム、スチレン−イソプレン共重合体ゴム、イ
ソプレン−ブタジエン共重合体ゴム等を挙げることがで
きるが、特に制限されるべきものではない。また、トレ
ッドに配設される組成物には、前記ジエン系ゴム及び超
高分子量ポリエチレンのほかに通常トレッドゴムに用い
られる他のゴムや配合剤、例えば、充填剤、老化防止
剤、加硫剤、加硫促進剤を含めることができ、これらの
種類、量については通常トレッドゴムに用いられる範囲
であって特に限定されるものでない。The rubber component includes natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene-butadiene terpolymer rubber, styrene-isoprene copolymer rubber, and isoprene-butadiene copolymer. Although a polymer rubber etc. can be mentioned, it is not particularly limited. Further, the composition disposed in the tread, other than the diene rubber and ultrahigh molecular weight polyethylene, other rubbers and compounding agents usually used for tread rubber, for example, fillers, antioxidants, vulcanizing agents , A vulcanization accelerator, and the types and amounts thereof are not particularly limited and are in the range usually used for tread rubber.
【００１７】本発明において、トレッドゴムが３〜35％
の発泡倍率の独立気泡を有することとしたのは、０℃付
近の氷表面に溶融した水分が多い状態において気孔によ
るミクロな吸排水効果を大きくし、優れた氷雪性能を発
揮させるためにはかかる独立気泡が不可欠だからであ
る。発泡は発泡剤によるもの、ガスの高圧ミキシングに
よるもののいずれの方法を用いてもよいが、発泡倍率が
３％未満では発泡の効果が十分でなく、一方35％を超え
るとトレッド剛性が不十分のため、耐摩耗性の低下や溝
底クラックの発生が大となる。In the present invention, the tread rubber is 3 to 35%
It is necessary to increase the microscopic water absorption and drainage effect by the pores and to exhibit excellent ice and snow performance in a state where there is a lot of molten water on the ice surface near 0 ° C. This is because closed cells are indispensable. Foaming may be carried out by a foaming agent or by high-pressure gas mixing, but if the foaming ratio is less than 3%, the foaming effect is not sufficient, while if it exceeds 35%, the tread rigidity is insufficient. As a result, the wear resistance is reduced and the groove bottom cracks are greatly generated.
【００１８】ここで、発泡ゴムの発泡率Ｖs は、次式 Ｖs ＝｛（ρo −ρg ）／（ρ1 −ρg ）−１｝×100
(％) ・・・(1) で表され、ρ1 は発泡ゴムの密度（ｇ／cm3 ）、ρo は
発泡ゴムの固相部の密度（ｇ／cm3 ）、ρg は発泡ゴム
の気泡内のガス部の密度（ｇ／cm3 ）である。発泡ゴム
は固相部と、固相部によって形成される空洞（独立気
泡）すなわち気泡内のガス部とから構成されている。ガ
ス部の密度ρg は極めて小さく、ほぼ零に近く、かつ固
相部の密度ρ1 に対して極めて小さいので、式(1) は、
次式 Ｖs ＝｛（ρo −ρ1 ）−１｝×100 (％)
・・・・(2) とほぼ同等となる。[0018] Here, the foaming rate V s of the foamed rubber is expressed by the following equation V s = {(ρ o -ρ g) / (ρ 1 -ρ g) -1} × 100
(%) (1) where ρ 1 is the density of the foamed rubber (g / cm 3 ), ρ o is the density of the solid phase portion of the foamed rubber (g / cm 3 ), and ρ g is the foamed rubber. Is the density (g / cm 3 ) of the gas part in the bubbles. The foamed rubber is composed of a solid phase portion and a cavity (closed cell) formed by the solid phase portion, that is, a gas portion in the air bubble. Since the density ρ g of the gas part is extremely small, almost close to zero, and extremely small with respect to the density ρ 1 of the solid phase part, the equation (1) becomes
Equation V s = {(ρ o -ρ 1) -1} × 100 (%)
... It is almost equivalent to (2).
【００１９】尚、本発明の空気入りタイヤにおいては、
上述の超高分子量ポリエチレンを配合した発泡ゴムを、
キャップ−ベース構造を有するトレッド部のキャップ部
のみに配設してもよい。In the pneumatic tire of the present invention,
Foam rubber blended with the above ultra high molecular weight polyethylene,
You may arrange | position only in the cap part of the tread part which has a cap-base structure.
【００２０】[0020]
【実施例】以下、実施例および比較例を挙げて本発明を
より具体的に説明する。下記の表１に、実施例および比
較例で使用した超高分子量ポリエチレンの分子量および
トレッド部ゴム中での平均粒径を示す。トレッド部ゴム
中における超高分子量ポリエチレンの平均粒径はトレッ
ド部ゴムサンプルから10ロットの試料を選び、光学顕微
鏡の視野内の超高分子量ポリエチレンの粒子20個の直径
を（最長直径＋最短直径）／２により測定し、各ロット
毎に平均粒径を算出し、更に10ロットの平均粒径の相加
平均を算出した。表 １ 表２に、表１に示す超高分子量ポリエチレンと組み合
わせた発泡ゴムマトリックスの配合処方（重量部）、並
びに得られた粒子混入発泡ゴムの発泡倍率および当該発
泡ゴムをタイヤトレッドに適用したときのタイヤ性能を
夫々示す。The present invention will now be described more specifically with reference to examples and comparative examples. Table 1 below shows the molecular weight of the ultrahigh molecular weight polyethylene used in Examples and Comparative Examples and the average particle size in the tread rubber. The average particle size of ultra-high molecular weight polyethylene in the tread rubber is selected from 10 lots of tread rubber samples and the diameter of 20 ultra-high molecular weight polyethylene particles in the visual field of the optical microscope is calculated as (longest diameter + shortest diameter) / 2, the average particle size was calculated for each lot, and the arithmetic mean of the average particle size of 10 lots was calculated. Table 1 Table 2 shows the formulation (parts by weight) of the foamed rubber matrix in combination with the ultrahigh molecular weight polyethylene shown in Table 1, the expansion ratio of the obtained foamed rubber mixed with particles, and the tire when the foamed rubber was applied to a tire tread. The performance is shown respectively.
【００２１】[0021]
【表２】 表２から明らかなように、本発明の空気入りタイヤであ
る実施例１においては、比較例１〜５に比し、氷上制動
性および操縦安定性の双方の性能が向上している。[Table 2] As is clear from Table 2, in Example 1 which is the pneumatic tire of the present invention, both the performance on braking on ice and the steering stability are improved as compared with Comparative Examples 1 to 5.
【００２２】[0022]
【発明の効果】以上説明してきたように、特定の発泡倍
率を有する発泡ゴムからなるトレッド組成物に特定粒径
の超高分子量ポリエチレンを所定量配合した本発明の空
気入りタイヤにおいては、耐摩耗性を低下させることな
く湿潤状態および乾燥状態にある氷雪路面上での駆動
性、制動性および操縦性を顕著に向上させることができ
る。As described above, the pneumatic tire of the present invention in which a predetermined amount of ultra-high molecular weight polyethylene having a specific particle diameter is blended with a tread composition comprising a foamed rubber having a specific expansion ratio, has a high abrasion resistance. Drivability, braking performance and maneuverability on wet and dry icy and snowy road surfaces can be significantly improved without lowering the driving performance.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) B60C 11/00 B60C 1/00 C08L 21/00 ──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. 7 , DB name) B60C 11/00 B60C 1/00 C08L 21/00
Claims (2)
0 μmの超高分子量ポリエチレンをゴム分 100重量部に
対し３〜100 重量部含有し、かつ３〜35％の発泡倍率の
独立気泡を有する発泡ゴムをトレッドに備えたことを特
徴とする空気入りタイヤ。An average particle size of 1 to 50 having a molecular weight of 500,000 or more.
A pneumatic tire characterized in that a tread is provided with foamed rubber containing 3 to 100 parts by weight of 0 μm ultrahigh molecular weight polyethylene based on 100 parts by weight of rubber and having closed cells with an expansion ratio of 3 to 35%. tire.
ベース構造を有するトレッド部のキャップ部に配設した
ことを特徴とする空気入りタイヤ。2. The method according to claim 1, wherein the rubber composition is a cap.
A pneumatic tire, wherein the tire is disposed on a cap of a tread having a base structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3171980A JP3021801B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3171980A JP3021801B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04368205A JPH04368205A (en) | 1992-12-21 |
| JP3021801B2 true JP3021801B2 (en) | 2000-03-15 |
Family
ID=15933308
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3171980A Expired - Fee Related JP3021801B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3021801B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5571350A (en) * | 1993-11-02 | 1996-11-05 | Bridgestone Corporation | Pneumatic tire with tread of matrix foamed rubber containing resin |
| JPH07126438A (en) * | 1993-11-02 | 1995-05-16 | Bridgestone Corp | Pneumatic tire |
| JP4608032B2 (en) * | 1997-06-18 | 2011-01-05 | 株式会社ブリヂストン | Vulcanized rubber moldings for tires |
| JP4137236B2 (en) * | 1998-07-03 | 2008-08-20 | 株式会社ブリヂストン | Rubber composition for tire tread and pneumatic tire |
| JP4788438B2 (en) * | 2006-03-30 | 2011-10-05 | 横浜ゴム株式会社 | Pneumatic tire |
| FR2952645B1 (en) | 2009-10-27 | 2011-12-16 | Michelin Soc Tech | PNEUMATIC BANDAGE WHOSE INTERNAL WALL HAS A THERMO-EXPANDABLE RUBBER LAYER |
| FR2953848B1 (en) * | 2009-11-27 | 2012-12-14 | Michelin Soc Tech | BANDAGE FOR A VEHICLE WITH A TREAD BAND COMPRISING A THERMO-EXPANSIBLE RUBBER COMPOSITION |
| JP2012057001A (en) * | 2010-09-07 | 2012-03-22 | Yokohama Rubber Co Ltd:The | Rubber composition for conveyer belt, and conveyer belt |
| US8813802B1 (en) * | 2013-11-13 | 2014-08-26 | The Goodyear Tire & Rubber Company | Pneumatic tire with rubber component containing thermoplastic/filler composite |
-
1991
- 1991-06-18 JP JP3171980A patent/JP3021801B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04368205A (en) | 1992-12-21 |
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