JPH09300910A - Pneumatic tire with tread rubber containing bubble - Google Patents
Pneumatic tire with tread rubber containing bubbleInfo
- Publication number
- JPH09300910A JPH09300910A JP8071813A JP7181396A JPH09300910A JP H09300910 A JPH09300910 A JP H09300910A JP 8071813 A JP8071813 A JP 8071813A JP 7181396 A JP7181396 A JP 7181396A JP H09300910 A JPH09300910 A JP H09300910A
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- JP
- Japan
- Prior art keywords
- resin
- rubber
- weight
- parts
- component
- 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.)
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- Tires In General (AREA)
- Laminated Bodies (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は気泡を含有するトレ
ッドゴムを備えた空気入りタイヤに関し、特に、ゴムマ
トリクス中に樹脂または樹脂複合体により被覆された気
泡を含有するゴム組成物をトレッドゴムに備えた、氷上
制動性及び耐摩耗性に優れた空気入りタイヤに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire provided with a tread rubber containing bubbles, and more particularly to a tread rubber containing a rubber composition containing bubbles covered with a resin or a resin composite in a rubber matrix. The present invention relates to a pneumatic tire having excellent braking performance on ice and excellent wear resistance.
【0002】[0002]
【従来の技術】近年、冬期においてもタイヤ交換するこ
となく、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いる。この種のタイヤは冬期
においても夏期と同様のドライグリップ性、ウェットグ
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充分な駆動性や制動性を有する
ものである。従来のこのようなタイヤに使用されるトレ
ッドゴムはサマー用トレッドゴムの低温での硬度を低く
したり、ガラス転移点の低いポリマーを使用したり、も
しくは低温での弾性率を適切に保てる軟化剤を用いたり
す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 the summer without replacing tires in the winter has been increasing. Tires of this type have the same dry grip, wet grip, steering stability, durability, and fuel economy as in summer, and also have sufficient drivability and braking performance on ice and snow. Is. Conventional tread rubber used for such tires is a softening agent that can reduce the hardness of summer tread rubber at low temperature, use a polymer having a low glass transition point, or can appropriately maintain the elastic modulus at low temperature. There are known methods for using.
【0003】しかしながら、前者の方法では、このポリ
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はないという問題があり、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
公報等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等の問題点が指
摘されている。However, in the former method, due to the hysteresis characteristic of this polymer, even if a moderate performance is exhibited in the snow and snow temperature region, the braking property and the maneuverability on a wet road surface or a dry road surface are not sufficient. The latter method is also disclosed in JP-A-55-135149, JP-A-58-199203, JP-A-60-137945, and the like.
It has been pointed out that the improvement of the performance on ice and snow has a large adverse effect on abrasion resistance and durability when driving on a general road.
【0004】また、いずれの技術を用いた場合でも、確
かに−5℃以下の比較的低温領域における、いわゆるド
ライ・オン・アイスでの氷雪性能においては良好な性能
を示すものの、0℃付近の湿潤状態、いわゆるウェット
・オン・アイスでの氷雪上性能においては、十分な摩擦
係数を得られず、駆動性、制動性および操縦安定性が十
分に改良されているとは言い難い。In addition, whichever technique is used, the ice-snow performance in so-called dry-on-ice is certainly good in a relatively low temperature range of -5 ° C or lower, but it is around 0 ° C. In the wet condition, that is, in the so-called wet-on-ice performance on snow and ice, it is difficult to say that a sufficient friction coefficient is obtained, and drivability, braking performance and steering stability are sufficiently improved.
【0005】これに対して、近年、トレッドゴム自体に
摩擦力向上のための工夫を加える技術が採用されてい
る。その第1の方法として、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)。一般的に、氷の表面には疑
似液体層と言われる層が存在する。そして、物体を氷の
上に押しつけ、滑らせると、疑似液体層が一部水膜に変
わるためにこの水膜が潤滑剤の役割を果たし、低い摩擦
係数を発現する。On the other hand, in recent years, a technique has been adopted in which a device for improving frictional force is added to the tread rubber itself. As a first method, there is a method in which a tread rubber is foamed by an appropriate method to generate closed cells (JP-A-63-89547). Generally, a layer called a pseudo liquid layer exists on the surface of ice. Then, when the object is pressed and slid on the ice, the pseudo liquid layer partially changes to a water film, and this water film plays a role of a lubricant, and exhibits a low coefficient of friction.
【0006】独立気泡を生成させて得られるトレッドゴ
ムの表面は、多数の気泡で覆われているため、氷面との
接触面内にて発生する水膜を流し除き、また、気孔部の
ミクロな運動に伴い、疑似液体層を除き去る(スクレイ
パー)効果の発現により、氷上高摩擦化を発現する。一
般的に氷雪上用のタイヤは、サイプをたくさん設けるこ
とで、ブロックのエッジを増やす工夫がなされている
が、その本質とするところは、ブロックのサイプによる
エッジ部分で、氷表面上の疑似液体層を除き去る機能に
あり、この効果を「マクロなエッジ効果」と呼ぶ。一
方、独立気泡ゴムにより、ミクロな凹凸を作り、その凸
部による機能の本質は、「ミクロなエッジ効果」にあ
る。Since the surface of the tread rubber obtained by generating closed cells is covered with a large number of bubbles, the water film generated in the contact surface with the ice surface is washed away, and the micropores in the pores are removed. With a great amount of exercise, the effect of removing the pseudo liquid layer (scraper) is exerted, and thus high friction on ice is exerted. Generally, tires for ice and snow are designed to increase the edge of the block by providing a large number of sipes, but the essential point is that the pseudo liquid on the ice surface is the edge of the block sipe. It has the function of removing layers, and this effect is called "macro edge effect". On the other hand, microscopic irregularities are created by the closed-cell rubber, and the essence of the function of the convexities is the “microscopic edge effect”.
【0007】この手法は、実際のタイヤトレッドに取り
入れられ、スタッドレスタイヤとして市販されている。
またトレッドゴムに各種の異物(砂、もみがらのような
天然物等)を混入し、タイヤ走行時にこれらの異物が抜
け落ちることによって気孔を発生させる方法も検討され
ている。この方法は、氷上高摩擦化のメカニズムとして
は発泡と同一のものである。これら第1の方法では、氷
面の疑似液体層を除き去る効果はあるものの、従来のス
パイクタイヤにある様な直接、固体である氷そのものを
引っ掻き壊すことで、高摩擦化を得る手法とは異なり、
性能的に十分満足のいくものではない。This method has been incorporated into actual tire treads and is commercially available as studless tires.
In addition, a method of mixing various foreign substances (natural substances such as sand and rice husk) into the tread rubber and causing the foreign substances to fall off during tire running to generate pores has been studied. This method is the same as foaming as a mechanism for increasing friction on ice. Although the first method has an effect of removing the pseudo liquid layer on the ice surface, it is a method for obtaining high friction by directly scratching the solid ice itself as in the conventional spike tire. Different,
It is not satisfactory in terms of performance.
【0008】第2の方法として、各種の高硬度材料をト
レッドゴム中に混入し、この高硬度材料中の氷面に対す
る引っ掻き効果を利用してトレッドゴムの氷上高摩擦化
を実現しようとしたものがある(特公昭46−3173
2号,特開昭51−147803号,特公昭56−52
057号公報,特公平6−102737号公報)。この
方法は、明らかに前記第1の方法とは異なったメカニズ
ムによるトレッドゴムの氷上高摩擦化法である。実際、
多くの場合、これらの高硬度材料を多量に混入すればす
る程、トレッドゴムは氷上高摩擦化される傾向にある。As a second method, various high hardness materials are mixed into the tread rubber, and the scratching effect on the ice surface in the high hardness material is utilized to achieve high friction on ice of the tread rubber. There is (Japanese Examined Sho 46-3173)
2, JP-A-51-147803, JP-B-56-52
No. 057, Japanese Patent Publication No. 6-102737). This method is a method for increasing the friction of the tread rubber on ice by a mechanism different from the first method. In fact,
In many cases, the greater the amount of these high hardness materials mixed, the higher the friction of the tread rubber on ice.
【0009】上述した従来技術のうち、第1の方法は、
トレッドゴムの発泡又は混入された異物が脱離した後の
表面凹凸の凸部で氷表面を引っ掻き、凹部で表面の水分
を吸排水するが、氷がより硬くなり、また、氷の表面が
溶けにくい低温下(通常の場合−3℃以下)では、吸排
水機能はあまり必要とされず、また、引っ掻き効果もあ
まり期待できない。Among the above-mentioned conventional techniques, the first method is
After the foaming of the tread rubber or the inclusion of foreign matter is released, the convex parts of the surface irregularities scratch the ice surface, and the concave parts absorb and drain the surface moisture, but the ice becomes harder and the ice surface melts. Under a difficult low temperature (normally -3 ° C or lower), the function of absorbing and draining water is not required so much, and the scratching effect cannot be expected so much.
【0010】一方、トレッドのマトリクスゴムに引っ掻
き効果の高い高硬度材料を混入する第2の方法の欠点
は、水分の多い0℃付近での氷上性能改良効果が小さ
く、また高硬度材料がゴムに親和性のない異物として存
在するため、耐摩耗性や破壊特性の低下が著しいことで
ある。On the other hand, the disadvantages of the second method in which the high hardness material having a high scratching effect is mixed in the matrix rubber of the tread have a small effect on improving the performance on ice at around 0 ° C. where the water content is high, and the high hardness material is used as the rubber. Since it is present as a foreign material having no affinity, the wear resistance and the fracture characteristics are significantly deteriorated.
【0011】この様な現状を踏まえ、発明者は、特に湿
潤状態にある氷雪路面上での性能向上を目的とし、sy
n−1,2−ポリブタジエン樹脂と硫黄、加硫促進剤、
C/B、スコーチ防止剤を配合した複合体粒子を得、発
泡トレッドゴムに混入することで耐摩耗性能との両立と
いう観点からの検討を行っていたが、一般市場の要求レ
ベルからはまだ充分とは言えず、更なる改善が求められ
ている。また、現実の氷面温度は日中から夜間にかけて
様々に変化するため、広い温度域でより安定した氷上性
能を示し、かつ耐摩耗性および破壊特性も著しく低下さ
せることのないタイヤトレッドが望まれている。In view of such a situation, the inventor aims to improve performance especially on a icy and snowy road surface in a wet state,
n-1,2-polybutadiene resin and sulfur, a vulcanization accelerator,
C / B and a scorch inhibitor were mixed to obtain composite particles, which were studied from the viewpoint of compatibility with wear resistance by mixing with foamed tread rubber, but it is still sufficient from the demand level of the general market. However, further improvement is required. In addition, since the actual ice surface temperature varies from daytime to nighttime, a tire tread that exhibits more stable on-ice performance in a wide temperature range and does not significantly reduce wear resistance and breaking characteristics is desired. ing.
【0012】また、従来の発泡ゴムは、除水・排水効果
といったタイヤ踏面内での氷路面との間で発生する水膜
を流し去ることにより、氷上摩擦係数を向上させる機能
を持っているが、ウェット・オン・アイス状態での大量
な水膜を除去するには限界があり、ウェット・オン・ア
イス状態での氷上摩擦係数の改善は難しい。又、もう1
つの氷上性能改善手段である、引っ掻き効果を付与する
ために、ミクロスパイクとして特定の粒径、硬度の粒子
を配合する方法で、ある程度改良されるが、引っ掻き効
果と、排水効果の相乗効果が少なく氷上性能レベルは、
まだ充分ではない。Further, the conventional foamed rubber has a function of improving the friction coefficient on ice by draining away the water film generated between the ice tread surface in the tread surface of the tire, such as water removal and drainage effects. However, there is a limit to removing a large amount of water film in the wet-on-ice state, and it is difficult to improve the friction coefficient on ice in the wet-on-ice state. Also another 1
This is a method of improving the performance on ice, which is a method of blending particles of specific particle size and hardness as micro spikes in order to give a scratching effect, but it is improved to some extent, but the synergistic effect of the scratching effect and the drainage effect is small. The performance level on ice is
Not enough yet.
【0013】相乗効果が小さい理由としては、上記の方
法では、粒子の硬さと接着性に反比例の関係があること
が挙げられる。すなわち、従来の技術では硬い粒子であ
る程、引っ掻き効果は大きいが、硬い材質であるほど、
ゴムマトリクスとの接着性が低下するため、タイヤ踏面
の摩擦表面において、粒子が脱離しやすくなり、効果的
なスパイク数が減少してしまい、引っ掻き効果が長続き
せず、又耐摩耗性、耐クラック性の低下を引き起こすと
いった問題が残る。又、上記の様な硬い粒子は、発泡剤
配合ゴムに添加すると、粒子界面で発泡してしまい、マ
トリクスとの接着力を低下させる。The reason why the synergistic effect is small is that the above method has an inverse relationship between the hardness of the particles and the adhesiveness. That is, in the conventional technology, the harder the particles, the greater the scratching effect, but the harder the material,
Since the adhesion with the rubber matrix is reduced, particles are easily detached on the friction surface of the tire tread, the number of effective spikes is reduced, the scratching effect does not last long, abrasion resistance, crack resistance There remains a problem that causes deterioration of sex. Further, when the hard particles as described above are added to the rubber containing the foaming agent, they are foamed at the particle interface and the adhesive force with the matrix is lowered.
【0014】[0014]
【発明が解決しようとする課題】そこで、本発明は、排
水効果および引っ掻き効果の最大の相乗効果を得るべ
く、ドライオンアイスにおいてのみならず、ウェットオ
ンアイスにおいても充分な制動性及び駆動性を得られる
新規なスタッドレスタイヤを提供することを目的とす
る。Therefore, in order to obtain the maximum synergistic effect of the drainage effect and the scratching effect, the present invention provides sufficient braking performance and drivability not only in dry-on-ice but also in wet-on-ice. The object is to provide a new studless tire obtained.
【0015】[0015]
【課題を解決するための手段】本発明の構成は以下の通
りである。 (1)天然ゴム、イソプレンゴム、スチレン・ブタジエ
ンゴム、ブタジエンゴム、イソブチレン−イソプレン共
重合体よりなる群から選択される少なくとも1種のジエ
ン系ポリマーをゴム成分とし、気泡含有率5〜35%の
発泡性気泡を含有するトレッドゴムを備えた空気入りタ
イヤにおいて、前記気泡個数の20%以上を、ゴム成分
100重量部に対し2.5〜20重量部配合されJIS
−K 6301−C形硬度計で測定される硬度が75以
上であり樹脂成分中10重量%以上の共役ジエン成分を
含有した樹脂または樹脂複合体により被覆したことを特
徴とする。なお、本明細書中、樹脂成分中の「共役ジエ
ン成分」とは、重合前のモノマー段階において共役ジエ
ンであることを意味するものとする。 (2)請前記樹脂または樹脂複合体の樹脂が、融点80
〜200℃の結晶性シンジオタクティック−1,2−ポ
リブタジエン樹脂(以下、SPB樹脂という)、及び、
10重量%以上の共役ジエン成分を有しTgが80℃以
上であるABS樹脂のうち少なくとも1種からなること
を特徴とする。The constitution of the present invention is as follows. (1) At least one diene polymer selected from the group consisting of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, and isobutylene-isoprene copolymer is used as a rubber component and has a bubble content of 5 to 35%. In a pneumatic tire provided with a tread rubber containing foamable bubbles, 20% or more of the number of bubbles is blended in an amount of 2.5 to 20 parts by weight based on 100 parts by weight of a rubber component.
The hardness is 75 or more as measured by a -K6301-C hardness tester, and the resin or resin composite is coated with a resin component containing 10% by weight or more of a conjugated diene component. In the present specification, the “conjugated diene component” in the resin component means a conjugated diene in the monomer stage before polymerization. (2) The resin of the contract or the resin composite has a melting point of 80.
To 200 ° C. crystalline syndiotactic-1,2-polybutadiene resin (hereinafter referred to as SPB resin), and
It is characterized by comprising at least one of ABS resins having a conjugated diene component of 10% by weight or more and a Tg of 80 ° C. or more.
【0016】(3)前記樹脂複合体が、樹脂100重量
部に対して硫黄0.3〜5重量部、加硫促進剤0.1〜
7.0重量部を配合してなることを特徴とする。 (4)前記樹脂複合体が、式0<X+10Y<2000
(式中、Xは、窒素吸着法比表面積(m2/g)、Yは樹
脂成分100重量部に対するカーボンブラックの配合部
数(重量部)を示す。)で表わされる関係を満足するカ
ーボンブラックを配合してなることを特徴とする。(3) The resin composite contains 0.3 to 5 parts by weight of sulfur, and 0.1 to 5 parts by weight of a vulcanization accelerator with respect to 100 parts by weight of the resin.
It is characterized by being mixed with 7.0 parts by weight. (4) The resin composite has the formula 0 <X + 10Y <2000.
(Wherein X represents a specific surface area (m 2 / g) by a nitrogen adsorption method, and Y represents a blending part (parts by weight) of carbon black with respect to 100 parts by weight of the resin component). It is characterized by being mixed.
【0017】[0017]
【発明の実施の形態】以下に本発明をより詳細に説明す
る。本発明にかかるゴム成分中のジエン系ポリマーとし
ては、天然ゴム、イソプレンゴム、スチレン・ブタジエ
ンゴム、ブタジエンゴム、イソブチレン−イソプレン共
重合体等、通常タイヤ用トレッドゴムとして用いられる
ポリマーが挙げられる。また、樹脂または樹脂複合体の
樹脂としては、共役ジエン含量が10重量%以上で、J
IS−C硬度が75以上の樹脂および樹脂複合体である
ことが必要であり、特に、結晶性シンジオタクティック
−1,2−ポリブタジエン樹脂、共役ジエンモノマーを
10重量%以上にて構成されTgが80℃以上であるA
BS樹脂が好ましい。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Examples of the diene polymer in the rubber component according to the present invention include polymers commonly used as tire tread rubbers such as natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, and isobutylene-isoprene copolymer. Further, as the resin or the resin of the resin composite, the conjugated diene content is 10% by weight or more, and J
It is necessary that the IS-C hardness be a resin or resin composite having a hardness of 75 or more, and in particular, a crystalline syndiotactic-1,2-polybutadiene resin and a conjugated diene monomer composed of 10% by weight or more and having a Tg of A above 80 ° C
BS resin is preferred.
【0018】トレッドゴムとしての配合内容は、ゴム補
強剤として、カーボンブラック及びシリカのうち少なく
とも1種をゴム成分100重量部に対して10〜100
重量部添加すると好ましい。また、老化防止剤、加硫
剤、加硫促進剤、加硫助剤など、通常使用されるものを
適宜使用できる。The compounding content of the tread rubber is such that at least one of carbon black and silica is used as a rubber reinforcing agent in an amount of 10 to 100 relative to 100 parts by weight of the rubber component.
It is preferable to add parts by weight. In addition, antioxidants, vulcanizing agents, vulcanization accelerators, vulcanization aids and the like which are usually used can be appropriately used.
【0019】本発明にかかるタイヤのトレッドゴム用の
ゴム組成物の製造方法としては、硬度、融点またはTg
等が本発明の範囲を満たす樹脂または樹脂複合体を、粒
径10〜200μmの状態で配合し、添加後加硫までの
混練り分散工程等において更に粒径が小さくなることを
回避するために、加硫までの加工温度を融点またはTg
未満に抑えておき、更に、樹脂融点またはTgより5℃
以上高い温度で加硫することにより、加硫時に樹脂を溶
融し、溶融した樹脂内部を選択的に発泡させることによ
り、気泡(独立気泡)表面に被覆層を形成する方法が挙
げられる。The method for producing the rubber composition for the tread rubber of the tire according to the present invention includes hardness, melting point or Tg.
In order to avoid further reduction of the particle size in the kneading / dispersing step after addition and vulcanization, etc., a resin or a resin composite satisfying the range of the present invention is blended in a particle size of 10 to 200 μm. , Melting point or Tg
The temperature should be kept below less than 5 ℃ from the melting point or Tg of the resin.
A method of forming a coating layer on the surface of bubbles (closed cells) by melting the resin during vulcanization by selectively vulcanizing at a high temperature and selectively foaming the inside of the melted resin is mentioned.
【0020】また、気泡表面に所望の被覆層を形成する
には、樹脂または樹脂複合体の混練り分散が終わった状
態において、粒径10〜200μmに分散していること
であり、このためには、上記のように粒径10〜200
μmの樹脂または樹脂複合体を添加する方法の他に、ペ
レット状またはブロック状の樹脂または樹脂複合体を添
加し、融点またはTg以上の温度で混練り分散する工程
の間に粒径10〜200μmに微粒子化させる方法もあ
る。なお、後者の方法は、過剰な混練りを避けるため
に、厳しい混練り条件コントロールが必要となる。Further, in order to form a desired coating layer on the surface of bubbles, the resin or the resin composite is dispersed in a particle size of 10 to 200 μm in a state where the resin is kneaded and dispersed. Has a particle size of 10 to 200 as described above.
In addition to the method of adding a resin or resin composite having a particle size of 10 μm, a pellet-shaped or block-shaped resin or resin composite is added, and a particle size is 10 to 200 μm during a step of kneading and dispersing at a temperature of melting point or Tg or more. There is also a method of making fine particles. The latter method requires strict kneading condition control in order to avoid excessive kneading.
【0021】以下に本発明の作用を説明する。気泡含有
率が5%未満は氷路上におけるゴム表面上の除水効果が
現れないため、氷上性能の改善が見られない。35%超
過では耐久性、耐摩耗性を悪化させるため好ましくな
い。The operation of the present invention will be described below. When the bubble content is less than 5%, the water removing effect on the rubber surface on the ice road does not appear, and therefore the improvement on ice performance cannot be seen. If it exceeds 35%, durability and wear resistance are deteriorated, which is not preferable.
【0022】樹脂または樹脂複合体で被覆された気泡個
数が20%未満では氷上性能の改善効果がなく、樹脂ま
たは樹脂複合体の配合量がゴム成分100重量部に対し
2.5重量部未満では総気泡個数の20%を被覆でき
ず、氷上効果がなく、20重量部超過では充分に被覆で
きるが、過剰分がマトリックス弾性率を増加させたり、
耐摩耗性の低下を招き好ましくない。JIS硬度が75
未満では、氷の硬さ(0℃で70)との差が少なくな
り、引っ掻き効果が得られない。If the number of bubbles covered with the resin or resin composite is less than 20%, there is no effect on improving the performance on ice, and if the amount of the resin or resin composite is less than 2.5 parts by weight with respect to 100 parts by weight of the rubber component. 20% of the total number of bubbles cannot be covered, there is no ice effect, and if it exceeds 20 parts by weight, it can be sufficiently covered, but the excess increases the matrix elastic modulus,
It is not preferable because it causes deterioration of wear resistance. JIS hardness is 75
When the amount is less than the above, the difference from the hardness of ice (70 at 0 ° C.) becomes small, and the scratching effect cannot be obtained.
【0023】また、樹脂または樹脂複合体中の共役ジエ
ン含量が10重量%未満ではゴムマトリクスと共架橋性
がなく、気泡表面被覆の状態は得られるものの、タイヤ
での走行時の摩耗表面からマトリックスとの接着不足に
よる脱離が起こり、所望する氷上性能が得られない。樹
脂の融点またはTgが80℃未満のものは、通常の混
練、熱入れ、押出し工程において、ゴム内で溶融分散し
てしまい、所望する独立気泡の表面被覆が困難となり、
融点またはTgが200℃超過のものは、通常の加硫温
度(100〜200℃)よりも高く、加硫時に溶融せ
ず、気泡の表面を被覆できない。さらに200℃を超え
る加硫温度では、タイヤの基本的な耐久性能など他の性
能が低下するため、現実的ではない。When the content of the conjugated diene in the resin or resin composite is less than 10% by weight, there is no co-crosslinking property with the rubber matrix and the state of the cell surface coating can be obtained, but the matrix is liable to be worn on the tire during running. Desorption occurs due to insufficient adhesion with, and the desired performance on ice cannot be obtained. If the melting point or Tg of the resin is less than 80 ° C., it will be melt-dispersed in the rubber in the usual kneading, heating and extruding steps, and it will be difficult to cover the desired closed-cell surface.
Those having a melting point or Tg of higher than 200 ° C. are higher than the usual vulcanization temperature (100 to 200 ° C.), do not melt during vulcanization, and cannot cover the surface of bubbles. Further, at a vulcanization temperature of higher than 200 ° C., other performances such as the basic durability performance of the tire deteriorate, which is not realistic.
【0024】樹脂が特定のSPB樹脂および特定のAB
S樹脂であると、ゴムマトリクスとの共加硫性、樹脂硬
さの点で好ましい。樹脂複合体中の硫黄の配合量が樹脂
100重量部に対して0.3重量部未満では接着力が不
足し、5.0重量部超過では複合体製造時の作業性が著
しく低下し、加硫促進剤の配合量が0.1重量部未満で
は接着力が不足し、7.0重量部超過では作業性におい
て好ましくない。The resin is a specific SPB resin and a specific AB
The S resin is preferable in terms of co-vulcanizability with the rubber matrix and resin hardness. If the content of sulfur in the resin composite is less than 0.3 parts by weight with respect to 100 parts by weight of the resin, the adhesive strength will be insufficient, and if it exceeds 5.0 parts by weight, workability during production of the composite will be significantly reduced. If the amount of the sulfur accelerator is less than 0.1 parts by weight, the adhesive strength will be insufficient, and if it exceeds 7.0 parts by weight, workability will be unfavorable.
【0025】また、樹脂複合体中に配合するカーボンブ
ラックは、本発明で規定した特定のカーボンブラックで
あると、樹脂複合体の硬さを向上させ、氷の引っ掻き効
果を向上させる点で好ましく、前記式の値が2000を
超えると樹脂複合体の製造時の混練り作業が困難とな
る。なお、前記式は種々の特性、配合部数について実験
した結果をプロットして得られた実験式である。The carbon black to be blended in the resin composite is preferably the specific carbon black defined in the present invention in order to improve the hardness of the resin composite and the effect of scratching ice, If the value of the above formula exceeds 2000, the kneading operation during the production of the resin composite becomes difficult. The above formula is an empirical formula obtained by plotting the results of experiments on various characteristics and compounding numbers.
【0026】なお、加硫工程前の樹脂または樹脂複合体
の樹脂の粒径は10〜200μmであることが好まし
い。10μm 未満の分散粒子では、気泡被覆には至ら
ず、200μm 超過では加硫後の被覆気泡径が大きす
ぎ、破壊核となり耐摩耗性、耐溝底クラック性が低下す
るからである。The particle size of the resin or resin of the resin composite before the vulcanization step is preferably 10 to 200 μm. This is because dispersed particles having a particle size of less than 10 μm do not cover the bubbles, and particles having a particle size of more than 200 μm cause the coated cell diameter after vulcanization to be too large to serve as fracture nuclei and reduce abrasion resistance and groove bottom crack resistance.
【0027】加硫温度は、樹脂または樹脂複合体の樹脂
の融点より5℃以上高いことが好ましいが、これより低
い場合は加硫中の樹脂の溶融が不充分で、被覆割合(コ
ーティング率)の低下を引き起こすため好ましくない。The vulcanization temperature is preferably higher than the melting point of the resin or the resin of the resin composite by 5 ° C. or more, but if it is lower than this, the melting of the resin during vulcanization is insufficient and the coating ratio (coating rate). It is not preferable because it causes a decrease in
【0028】[0028]
【実施例】以下に本発明を実施例に基づいて説明する。
各実施例及び各比較例とも、表1記載の配合、条件に基
づき、混練り、加硫等を行い、ゴム組成物を得、タイヤ
を作製した。使用樹脂の詳細を表2、3および4にそれ
ぞれ記載する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
In each of the examples and the comparative examples, kneading, vulcanization and the like were performed based on the composition and conditions shown in Table 1 to obtain a rubber composition and to manufacture a tire. Details of the resins used are shown in Tables 2, 3 and 4, respectively.
【0029】具体的なゴム組成物の製造法は以下の通り
である。各ゴムは第1ステージにて、ポリマー、カーボ
ンブラック、ステアリン酸、ZnO、老化防止剤などの
混練分散を確保し、第2ステージにて、硫黄、加硫促進
剤、発泡剤を混練分散させるといった2段階の混練を行
う。OOCバンバリーミキサーを使用し、スタート温度
70℃、回転数80rpm、ラム圧力5kg/cm2 で
所望する温度に達するまで混練を行う。A specific method for producing the rubber composition is as follows. For each rubber, in the first stage, kneading and dispersion of polymer, carbon black, stearic acid, ZnO, anti-aging agent, etc. is ensured, and in the second stage, sulfur, vulcanization accelerator and foaming agent are kneaded and dispersed. Two-stage kneading is performed. Kneading is performed using an OOC Banbury mixer at a starting temperature of 70 ° C., a rotation speed of 80 rpm, and a ram pressure of 5 kg / cm 2 until a desired temperature is reached.
【0030】本検討では、樹脂および樹脂複合体の形態
が粒子状であり、その大きさが所望の範囲にあるため、
混練による溶融分散の必要はない。よって、第2ステー
ジにて樹脂および樹脂複合体を投入し、溶融させない分
散状態にとどめるため、95℃に到達した時点で混練を
終了させた。また、ゴムの加工温度(樹脂または樹脂複
合体を混練分散した後の、発泡剤、加硫剤等の混練分
散、熱入れなどの温度)は、95℃を上限とし、加硫前
の樹脂および樹脂複合体粒子の粒径が40μmであるこ
とを確認した。In this study, since the morphology of the resin and the resin composite is particulate and the size thereof is within the desired range,
There is no need for melt dispersion by kneading. Therefore, in order to maintain the dispersion state in which the resin and the resin composite were not melted in the second stage, the kneading was terminated when the temperature reached 95 ° C. In addition, the processing temperature of rubber (the temperature of kneading and dispersing a foaming agent, a vulcanizing agent, etc. after kneading and dispersing a resin or a resin composite, the temperature of heating, etc.) has an upper limit of 95 ° C. It was confirmed that the particle size of the resin composite particles was 40 μm.
【0031】このゴム組成物及びタイヤにつき、表1中
記載の各性能を下記の方法で測定した。 粘弾性 粘弾性測定装置(東洋精機(株)L−IR型)を用い、
長さ20mm、幅4.7mm、厚さ2mmのサンプルを
取り付け、1.7kgf/cm2 の初期張力を与え、振
幅歪み1%、50Hzの周波数にて、−20℃下の動的
弾性率を求めた。With respect to the rubber composition and the tire, the performances shown in Table 1 were measured by the following methods. Viscoelasticity Using a viscoelasticity measuring device (Toyo Seiki Co., Ltd. L-IR type),
A sample with a length of 20 mm, a width of 4.7 mm, and a thickness of 2 mm was attached, an initial tension of 1.7 kgf / cm 2 was applied, and an amplitude strain of 1% and a dynamic elastic modulus under −20 ° C. at a frequency of 50 Hz. I asked.
【0032】気泡含有率 発泡の気泡含有率Vs は、次式 Vs ={(ρ0 −ρg )/(ρ1 −ρg )−1}×100(%) ---(1) で表わされ、ρ1 は発泡ゴムの密度(g/cm3)、ρ0 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 ={(ρ0 /ρ1 )−1}×100(%) ---(2) とほぼ同等となる。Bubble content rate The bubble content rate V s of foaming is expressed by the following equation V s = {(ρ 0 −ρ g ) / (ρ 1 −ρ g ) −1} × 100 (%) --- (1) Where ρ 1 is the density of the foamed rubber (g / cm 3 ), ρ 0 is the density of the solid phase part of the foamed rubber (g / cm 3 ), and ρ g is the density of the gas part inside the bubbles of the foamed rubber. (G / cm 3 ). 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 bubble. Since the density ρ g of the gas portion is extremely small, close to zero, and extremely small with respect to the density ρ 1 of the solid phase portion, the equation (1) is expressed by the following equation V s = {(ρ 0 / ρ 1 ) − 1} × 100 (%) --- (2).
【0033】気泡径ならびに加硫前の粒径 平均独立気泡径ならびに加硫前の樹脂および樹脂複合体
の粒径の測定法は、サンプルゴム組成物から、ブロック
状の試料を切り出し、倍率100〜400の光学顕微鏡
で撮影し、200個以上の独立気泡または樹脂粒子もし
くは樹脂複合体粒子の直径を測定し、算術的平均値とし
て表す。Cell diameter and particle diameter before vulcanization The average closed cell diameter and the particle diameter of the resin and resin composite before vulcanization are measured by cutting a block-shaped sample from the sample rubber composition and multiplying the magnification by 100 to 100. The diameter of 200 or more closed cells or resin particles or resin composite particles was measured by photographing with an optical microscope of 400, and is represented as an arithmetic mean value.
【0034】コーティング率(%) サンプルのカット面を光学顕微鏡でとらえ、1mm2 あ
たりの総気泡個数に対するコーティングされた気泡個数
をカウントし、%を算出する。Coating rate (%) The cut surface of the sample is observed by an optical microscope, and the number of coated bubbles with respect to the total number of bubbles per 1 mm 2 is counted to calculate%.
【0035】氷上制動性能 表1記載の配合のゴム組成物をトレッド部に使用したタ
イヤサイズ165SR13のタイヤを作製し、社内テス
トコースにてアスファルト路面上を直進200kmの慣
らし走行を行った後、氷温度−2℃及び−8℃にて時速
20km/hから制動したときの制動距離の逆数を、指
数で表示した。数値は大きい程良好である。Braking performance on ice A tire having a tire size of 165SR13 was prepared by using a rubber composition having the composition shown in Table 1 in a tread portion, and after running-in straight for 200 km on an asphalt road surface on an in-house test course, ice was used. The reciprocal of the braking distance when braking from a speed of 20 km / h at a temperature of −2 ° C. and −8 ° C. is represented by an index. The larger the value, the better.
【0036】耐摩耗性能 上記と同様のタイヤを作製し、各タイヤを2本、排気量
1500ccの乗用車のドライブ軸に取り付け、社内テ
ストコースのコンクリート路面を60km/hで走行さ
せ、溝深さの変化量を指数表示した。数値が大きい程良
好である。Abrasion resistance performance A tire similar to the above was prepared, two tires each were attached to the drive shaft of a passenger car with a displacement of 1500 cc, and the concrete road surface of an in-house test course was run at 60 km / h to determine the groove depth. The amount of change was displayed as an index. The higher the value, the better.
【0037】外観 上記の同様のタイヤを作製し、各タイヤを2本、排気量
1500ccの乗用車のドライブ軸に取り付け、社内テ
ストコースの周回路を7000km走行し、溝底、サイ
プ底のクラック長さを4段階で表した。 ◎ 発生なし ○ 0.5mm以内 △ 1mm以内 × 1mm以上Appearance A tire similar to the one described above was produced, two tires each were attached to a drive shaft of a passenger car having a displacement of 1500 cc, and a peripheral circuit of an in-house test course was run for 7,000 km, and crack lengths at the groove bottom and sipe bottom were measured. Was expressed in four steps. ◎ No occurrence ○ Within 0.5 mm △ Within 1 mm × 1 mm or more
【0038】[0038]
【表1】 [Table 1]
【0039】*1:ジベンゾチアジルジスルフィド(加
硫促進剤) *2:N−シクロヘキシル−2−ベンゾチアジル−スル
フェンアミド(加硫促進剤) *3:ジニトロソペンタメチレンテトラミン *4:DPT:尿素=1:1(重量比) *5:−8℃がドライ・オン・アイスに相当し、−2℃
がウェット・オン・アイスに相当する。 なお、氷上制動性能および耐摩耗性能を表す指数は、実
施例1〜10、比較例1〜7については、比較例2をコ
ントロールとし、実施例11は比較例8をコントロー
ル、実施例12は比較例9をコントロールとする。* 1: Dibenzothiazyl disulfide (vulcanization accelerator) * 2: N-cyclohexyl-2-benzothiazyl-sulfenamide (vulcanization accelerator) * 3: Dinitrosopentamethylenetetramine * 4: DPT: urea = 1: 1 (weight ratio) * 5: -8 ° C corresponds to dry-on-ice, -2 ° C
Is equivalent to wet on ice. In addition, as for the indexes representing the braking performance on ice and the wear resistance performance, for Examples 1 to 10 and Comparative Examples 1 to 7, Comparative Example 2 was used as a control, Example 11 was used to control Comparative Example 8, and Example 12 was used to compare. Example 9 is used as a control.
【0040】[0040]
【表2】 [Table 2]
【0041】[0041]
【表3】 [Table 3]
【0042】[0042]
【表4】 [Table 4]
【0043】*6:N−オキシジエチレン−2−ベンゾ
チアゾリルスルフェンアミド *7:日本モンサント製 サントガードPVI25 *8:樹脂を100重量部としたときの割合 *9:樹脂重量に対する割合* 6: N-oxydiethylene-2-benzothiazolylsulfenamide * 7: Santo Guard PVI25 manufactured by Nippon Monsanto * 8: Ratio when resin is 100 parts by weight * 9: Ratio to resin weight
【0044】実施例1〜4および比較例2より、樹脂ま
たは樹脂複合体の硬度が高い方が氷上制動性能が向上す
ることがわかる。実施例5〜7および比較例3より、共
架橋成分としての共役ジエン成分が多い方が、氷上制動
性能及び耐摩耗性能が良好であることがわかる。実施例
8、9および比較例4、5より、樹脂の配合量が少ない
と氷上制動性能が向上せず、多すぎると耐摩耗性が低下
することがわかる。From Examples 1 to 4 and Comparative Example 2, it is understood that the higher the hardness of the resin or resin composite, the better the braking performance on ice. From Examples 5 to 7 and Comparative Example 3, it can be seen that the more the conjugated diene component as the co-crosslinking component is, the better the braking performance on ice and the wear resistance performance are. From Examples 8 and 9 and Comparative Examples 4 and 5, it can be seen that when the amount of the resin blended is small, the braking performance on ice does not improve, and when it is too large, the wear resistance decreases.
【0045】比較例1および実施例10より、樹脂硬度
が低いと氷上制動性能が向上しないことがわかる。比較
例2、6、7より気泡含有率が高すぎると氷上性能は向
上するが、耐摩耗性能が悪化することがわかる。実施例
11とコントロールの比較例8より、同じ高気泡含有率
で氷上性能向上効果がられる。実施例12とコントロー
ルの比較例9より、同じ低気泡含有率で氷上性能向上効
果、耐摩耗向上効果が見られる。From Comparative Example 1 and Example 10, it is understood that if the resin hardness is low, the braking performance on ice is not improved. It can be seen that when the bubble content is too high as compared with Comparative Examples 2, 6, and 7, the performance on ice is improved, but the wear resistance performance is deteriorated. From Example 11 and Comparative Example 8 of the control, the effect of improving the performance on ice can be obtained with the same high bubble content rate. From Example 12 and Comparative Example 9 of the control, the effect of improving performance on ice and the effect of improving wear resistance can be seen at the same low bubble content.
【0046】[0046]
【発明の効果】本発明によると、従来の発泡ゴムにおけ
る排水効果に加えて、気泡の被覆層により引っ掻き効果
をも得ることができるので、ドライオンアイスのみなら
ずウェットオンアイスにおいても氷上摩擦係数を高め、
優れた氷上性能および耐摩耗性能を有する空気入りタイ
ヤを提供することができるという効果を得られる。According to the present invention, in addition to the drainage effect of the conventional foamed rubber, a scratching effect can be obtained by the bubble coating layer. Therefore, not only dry-on ice but also wet-on ice has a friction coefficient on ice. Increase
It is possible to obtain the effect of being able to provide a pneumatic tire having excellent on-ice performance and wear resistance performance.
【0047】また、被覆層がゴムと強固に接着し、補強
層を形成しているために、気泡表面から発生するミクロ
な亀裂の生成、成長を抑制でき、耐摩耗性、耐久性を向
上させることができるという効果も得られる。Further, since the coating layer firmly adheres to the rubber and forms the reinforcing layer, it is possible to suppress the generation and growth of microcracks generated from the cell surface, and improve the wear resistance and durability. The effect that can be obtained is also obtained.
Claims (4)
ブタジエンゴム、ブタジエンゴム、イソブチレン−イソ
プレン共重合体よりなる群から選択される少なくとも1
種のジエン系ポリマーをゴム成分とし、気泡含有率5〜
35%の発泡性気泡を含有するトレッドゴムを備えた空
気入りタイヤにおいて、前記気泡個数の20%以上を、
ゴム成分100重量部に対し2.5〜20重量部配合さ
れJIS−C硬度が75以上であり樹脂成分中10重量
%以上の共役ジエン成分を含有した樹脂または樹脂複合
体により被覆したことを特徴とする気泡を含有するトレ
ッドゴムを備えた空気入りタイヤ。1. Natural rubber, isoprene rubber, styrene
At least one selected from the group consisting of butadiene rubber, butadiene rubber, and isobutylene-isoprene copolymer.
A diene-based polymer as a rubber component and a bubble content rate of 5 to
In a pneumatic tire provided with a tread rubber containing 35% of foamable bubbles, 20% or more of the number of bubbles is
2.5 to 20 parts by weight per 100 parts by weight of the rubber component, JIS-C hardness of 75 or more, and coated with a resin or resin composite containing 10% by weight or more of the conjugated diene component in the resin component A pneumatic tire having a tread rubber containing air bubbles.
点80〜200℃の結晶性シンジオタクティック−1,
2−ポリブタジエン樹脂(以下、SPB樹脂という)、
及び、10重量%以上の共役ジエン成分を含有しガラス
転移点(Tg)が80℃以上であるABS樹脂のうち少
なくとも1種からなることを特徴とする請求項1記載の
気泡を含有するトレッドゴムを備えた空気入りタイヤ。2. The crystalline syndiotactic-1, which has a melting point of 80 to 200 ° C., of the resin or resin of the resin composite,
2-polybutadiene resin (hereinafter referred to as SPB resin),
And at least one ABS resin having a glass transition point (Tg) of 80 ° C. or higher, containing 10% by weight or more of a conjugated diene component, and the bubble-containing tread rubber according to claim 1. Pneumatic tire with.
対して硫黄0.3〜5重量部、加硫促進剤0.1〜7.
0重量部を配合してなることを特徴とする請求項1また
は2記載の気泡を含有するトレッドゴムを備えた空気入
りタイヤ。3. The resin composite contains 0.3 to 5 parts by weight of sulfur, 100 to 7 parts by weight of resin, and 0.1 to 7 parts of a vulcanization accelerator.
The pneumatic tire provided with the tread rubber containing bubbles according to claim 1 or 2, wherein 0 part by weight is blended.
2000(式中、Xは、窒素吸着法比表面積(m2/
g)、Yは樹脂成分100重量部に対するカーボンブラ
ックの配合部数(重量部)を示す。)で表わされる関係
を満足するカーボンブラックを配合してなることを特徴
とする請求項1、2または3記載の気泡を含有するトレ
ッドゴムを備えた空気入りタイヤ。4. The resin composite has the formula 0 <X + 10Y <
2000 (In the formula, X is a nitrogen adsorption method specific surface area (m 2 /
g) and Y represent the number of parts (parts by weight) of carbon black mixed with 100 parts by weight of the resin component. The pneumatic tire provided with the tread rubber containing bubbles according to claim 1, 2 or 3, wherein carbon black satisfying the relationship represented by (4) is blended.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8071813A JPH09300910A (en) | 1995-03-29 | 1996-03-27 | Pneumatic tire with tread rubber containing bubble |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7155695 | 1995-03-29 | ||
JP7-71556 | 1995-03-29 | ||
JP5739096 | 1996-03-14 | ||
JP8-57390 | 1996-03-14 | ||
JP8071813A JPH09300910A (en) | 1995-03-29 | 1996-03-27 | Pneumatic tire with tread rubber containing bubble |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH09300910A true JPH09300910A (en) | 1997-11-25 |
Family
ID=27296245
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8071813A Pending JPH09300910A (en) | 1995-03-29 | 1996-03-27 | Pneumatic tire with tread rubber containing bubble |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH09300910A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007112928A (en) * | 2005-10-21 | 2007-05-10 | Bridgestone Corp | Rubber composition and tire using the same |
-
1996
- 1996-03-27 JP JP8071813A patent/JPH09300910A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007112928A (en) * | 2005-10-21 | 2007-05-10 | Bridgestone Corp | Rubber composition and tire using the same |
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Date | Code | Title | Description |
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A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20040518 |