JP3054238B2 - Pneumatic tire - Google Patents
Pneumatic tireInfo
- Publication number
- JP3054238B2 JP3054238B2 JP3171979A JP17197991A JP3054238B2 JP 3054238 B2 JP3054238 B2 JP 3054238B2 JP 3171979 A JP3171979 A JP 3171979A JP 17197991 A JP17197991 A JP 17197991A JP 3054238 B2 JP3054238 B2 JP 3054238B2
- Authority
- JP
- Japan
- Prior art keywords
- rubber
- tread
- ice
- conjugated diene
- thermoplastic elastomer
- 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 66
- 239000005060 rubber Substances 0.000 claims description 60
- 150000001993 dienes Chemical class 0.000 claims description 21
- 229920002725 thermoplastic elastomer Polymers 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 13
- 238000005187 foaming Methods 0.000 claims description 8
- -1 vinyl aromatic hydrocarbon Chemical class 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 5
- 229920002554 vinyl polymer Polymers 0.000 claims description 4
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 15
- 238000004132 cross linking Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000005299 abrasion Methods 0.000 description 6
- 239000000806 elastomer Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 229920000642 polymer Polymers 0.000 description 5
- 239000004793 Polystyrene Substances 0.000 description 4
- 229920001400 block copolymer Polymers 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 229920002223 polystyrene Polymers 0.000 description 4
- 239000007790 solid phase Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 239000011115 styrene butadiene Substances 0.000 description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 description 3
- 229920000468 styrene butadiene styrene block copolymer Polymers 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920002857 polybutadiene Polymers 0.000 description 2
- 229920001195 polyisoprene Polymers 0.000 description 2
- 230000002393 scratching effect Effects 0.000 description 2
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 229920005683 SIBR Polymers 0.000 description 1
- 239000004902 Softening Agent Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000003712 anti-aging effect Effects 0.000 description 1
- FACXGONDLDSNOE-UHFFFAOYSA-N buta-1,3-diene;styrene Chemical compound C=CC=C.C=CC1=CC=CC=C1.C=CC1=CC=CC=C1 FACXGONDLDSNOE-UHFFFAOYSA-N 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229920003244 diene elastomer Polymers 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 125000005575 polycyclic aromatic hydrocarbon group Chemical group 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
- Tires In General (AREA)
- Tyre Moulding (AREA)
Description
【0001】[0001]
【産業上の利用分野】この発明は、空気入りタイヤ、特
に夏季における操縦性能、耐久性能及び耐摩耗性を損な
うことなく、氷雪路面上における駆動性、制動性及び操
縦性を著しく改良し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, particularly a pneumatic tire having significantly improved driving, braking and maneuverability on icy and snowy roads without impairing the steering performance, durability and wear resistance in summer. Regarding tires.
【0002】[0002]
【従来の技術】従来の空気入りタイヤにおいては、氷雪
路面を走行する際の駆動性、制動性及び操縦性を確保す
る為にスパイクピンをトレッド表部に打ち込んだスパイ
クタイヤを多用してきた。しかしながら、このようなタ
イヤは、スパイクピン自体の摩耗や道路の摩耗損傷によ
り粉塵を発生させ、大きな社会問題となっている。これ
に対処する為にスパイクピンの突出量及び打ち込み数の
規制並びにスパイクピンの材質等の検討がなされている
が、前記社会問題の根本的解決策とはなっていない。2. Description of the Related Art Conventional pneumatic tires often use spike tires in which spike pins are driven into a tread surface in order to ensure driving, braking, and maneuverability when traveling on icy and snowy road surfaces. However, such a tire generates dust due to wear of the spike pin itself or wear and tear of the road, and is a major social problem. In order to cope with this, regulations on the amount of spike pins projecting and the number of spike pins, materials of spike pins, and the like have been studied, but they have not been a fundamental solution to the social problem.
【0003】一方、近年スパイクやチェーン等を使用せ
ずに氷雪路面上における駆動性、制動性及び操縦性を有
するスタッドレスタイヤが検討され、急速に普及しつつ
あるが、いまだスパイクタイヤ対比充分な氷雪上性能が
発揮されているとはいい難い。従来よりスタッドレスタ
イヤのトレッドゴム質については、低温時のゴム弾性を
確保するためにガラス転移点の低い重合体を用いた配合
が使われている。しかしながら、このような重合体のヒ
ステリシス特性によっては、氷雪温度領域ではある程度
の性能が発揮されても、湿潤路面や乾燥路面での制動
性、操縦性が充分でないという問題点がある。On the other hand, in recent years, studless tires having driving, braking, and maneuverability on icy and snowy road surfaces without using spikes or chains have been studied and are rapidly spreading, but still have sufficient snow and snow compared to spiked tires. It is difficult to say that the performance is excellent. Conventionally, for the tread rubber of studless tires, a compound using a polymer having a low glass transition point has been used in order to ensure rubber elasticity at low temperatures. However, depending on the hysteresis characteristics of such a polymer, there is a problem that even if a certain degree of performance is exhibited in an ice-snow temperature range, braking performance and maneuverability on wet or dry road surfaces are not sufficient.
【0004】また、特開昭55-135149 号、特開昭58-199
203 号、特開昭60-137945 号公報などに開示されている
ようにトレッドゴムに軟化剤や可塑剤を多量配合したゴ
ム組成物を用いることにより、同様に低温特性を改良す
る方法も知られているが、これらの手法は氷雪上性能の
改良の程度の割には、一般路を走行した際の耐摩耗性の
低下やトレッドゴムのセパレーション発生などの問題点
が大きい。Further, Japanese Patent Application Laid-Open Nos. 55-135149 and 58-199
No. 203, Japanese Unexamined Patent Publication No. 60-137945, etc., a method of similarly improving low-temperature characteristics by using a rubber composition in which a large amount of a softening agent or a plasticizer is blended with tread rubber is also known. However, these methods have many problems such as a decrease in wear resistance when running on a general road and occurrence of separation of tread rubber, although the performance on ice and snow is improved.
【0005】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。また、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ひっかき効果を
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
たものもある (特公昭46-31732号, 特開昭51-147803
号, 特公昭56-52057号公報) 。しかしながら、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。
また、トレッドのマトリックスゴムにひっかき効果の高
い高硬度材料を混入する場合には、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、耐摩擦性や破
壊特性の低下が著しかった。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 scraping ice accompanying micro-movement of the pores develop on ice. Develop high friction properties. In addition, there is a method in which various high-hardness materials are mixed into tread rubber, and the friction effect of the tread rubber on ice is increased by using a scratching effect on the ice surface in the high-hardness material (Japanese Patent Publication No. No. 31732, JP-A-51-147803
No., JP-B-56-52057). However, when foamed rubber is used for the tread, it cannot always be said that the tire durability such as abrasion resistance is at a satisfactory level.
In addition, when a high-hardness material having a high scratching effect is mixed into the matrix rubber of the tread, the effect of improving the performance on ice near 0 ° C with a large amount of water is small, and the high-hardness material is present as a foreign material having no affinity for the rubber. As a result, the friction resistance and fracture characteristics were significantly reduced.
【0006】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.
【0007】[0007]
【発明が解決しようとする課題】この発明の目的は、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 icy and snowy roads 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. .
【0008】[0008]
【課題を解決するための手段】本発明者らは、ビニル芳
香族炭化水素共役ジエン系ブロック型熱可塑性エラスト
マーにあらかじめ内部架橋構造を施すことによってこれ
を所定の発泡ゴムのトレッドゴム中に充填した際に、こ
れが溶融流動することなくドメインを形成し、トレッド
部発泡ゴムの氷雪上における摩擦係数を向上させるこ
と、並びに該熱可塑性エラストマーがマトリックス部発
泡ゴムと共架橋反応を起こすため、この熱可塑性エラス
トマーの充填の有無にかかわらず、トレッドゴム組成物
として同等の耐摩耗性を維持することを確かめ、この発
明を完成するに至った。Means for Solving the Problems The present inventors preliminarily applied an internal cross-linking structure to a vinyl aromatic hydrocarbon conjugated diene-based thermoplastic elastomer and filled it into a predetermined foamed rubber tread rubber. At this time, this forms domains without melting and flowing, and improves the coefficient of friction of the tread foamed rubber on ice and snow, and also causes the thermoplastic elastomer to undergo a co-crosslinking reaction with the matrix foamed rubber. It was confirmed that the tread rubber composition maintained the same abrasion resistance irrespective of the presence or absence of the elastomer, and completed the present invention.
【0009】すなわち、この発明は、100 %伸張時にお
ける引張応力の増加率が10〜1000%の範囲内となるまで
内部架橋させた、平均粒径1〜500 μmのビニル芳香族
炭化水素共役ジエンブロック型熱可塑性エラストマーを
ゴム分100 重量部に対し3〜100 重量部含有し、かつ3
〜35%の発泡率の独立気泡を有する発泡ゴムをトレッド
に配設した空気入りタイヤである。That is, the present invention relates to a vinyl aromatic hydrocarbon conjugated diene having an average particle diameter of 1 to 500 μm, which is internally cross-linked until the rate of increase in tensile stress at 100% elongation falls within the range of 10 to 1000%. 3 to 100 parts by weight of a block type thermoplastic elastomer per 100 parts by weight of rubber, and 3
This is a pneumatic tire in which a foamed rubber having closed cells having a foaming rate of about 35% is disposed in a tread.
【0010】[0010]
【作 用】この発明に使用される内部架橋させた芳香族
炭化水素共役ジエン系ブロック型熱可塑性エラストマー
は、芳香族炭化水素共役ジエン系ブロック型熱可塑性エ
ラストマーに従来行われる硫黄架橋系、過酸化物架橋
系、放射線架橋系などの種々の架橋系のいずれを適用し
てもよく、架橋の方法とか架橋構造は特に限定されな
い。DESCRIPTION OF THE PREFERRED EMBODIMENTS The internally crosslinked aromatic hydrocarbon conjugated diene block type thermoplastic elastomer used in the present invention is the same as the conventional sulfur crosslinked type aromatic peroxide conjugated diene block type thermoplastic elastomer. Any of various crosslinking systems such as a product crosslinking system and a radiation crosslinking system may be applied, and the crosslinking method and the crosslinking structure are not particularly limited.
【0011】架橋反応の対象である芳香族炭化水素共役
ジエン系ブロック型熱可塑性エラストマーは、芳香族炭
化水素共役ジエンを主体とする非ゴム重合体ブロックセ
グメント(以下ポリ芳香族炭化水素共役ジエンブロック
という。)を少なくとも1個、好ましくは1〜2個、ゴ
ム状重合体ブロックセグメント(以下ゴムブロックとい
う。)を少なくとも1個含有するものである。このよう
な芳香族炭化水素共役ジエン系ブロック型熱可塑性エラ
ストマーは、例えばポリスチレンブロックを両端部に有
し、中間にゴムブロックを有する分子構造、ポリスチレ
ンブロックが一方だけで他方がゴムブロックからなる構
造、ポリスチレン端部が3個以上あって、これらをゴム
ブロックで結ぶ構造、更に、上記構造においてポリスチ
レンブロックとゴムブロックが交互に更に導入された構
造などである。ゴムブロックとしては、ポリブタジエン
ブロックやポリイソプレンブロックなどのポリオレフィ
ン系のエラストマーブロックであればよく、特に限定さ
れるものではないが、これらの中で有機リチウム化合物
触媒によるスチレン−ブタジエン−スチレン(S−B−
S)型ブロック共重合体エラストマー又はスチレン−ブ
タジエン(S−B)型ブロック共重合体エラストマーが
好ましい。The aromatic hydrocarbon conjugated diene block type thermoplastic elastomer to be subjected to the crosslinking reaction is a non-rubber polymer block segment mainly composed of an aromatic hydrocarbon conjugated diene (hereinafter referred to as a polyaromatic hydrocarbon conjugated diene block). ), Preferably at least one, and at least one rubber-like polymer block segment (hereinafter referred to as a rubber block). Such an aromatic hydrocarbon conjugated diene-based thermoplastic elastomer has, for example, a molecular structure having a polystyrene block at both ends and a rubber block in the middle, a structure in which only one polystyrene block and the other are rubber blocks, It has a structure in which there are three or more polystyrene ends and these are connected by a rubber block, and a structure in which a polystyrene block and a rubber block are further introduced alternately in the above structure. The rubber block may be a polyolefin-based elastomer block such as a polybutadiene block or a polyisoprene block, and is not particularly limited. Among them, styrene-butadiene-styrene (S-B −
An S) type block copolymer elastomer or a styrene-butadiene (SB) type block copolymer elastomer is preferred.
【0012】これらの芳香族炭化水素共役ジエン系ブロ
ック型熱可塑性エラストマーの製造法は、よく知られて
おり、例えば特開昭60−243109号公報及び特公昭48−24
23号公報には、有機Li化合物触媒によるS−B−S型ブ
ロック共重合体エラストマーが、特公昭36−19286 号公
報には同様な触媒によるS−B型及びS−B−S型ブロ
ック共重合体エラストマーの製造が記載されている。Methods for producing these aromatic hydrocarbon conjugated diene-based thermoplastic elastomers are well known, and are described, for example, in JP-A-60-243109 and JP-B-48-24.
No. 23 discloses an SBS type block copolymer elastomer using an organic Li compound catalyst, and Japanese Patent Publication No. 36-19286 discloses an SB type and SBS type block copolymer using a similar catalyst. The preparation of polymeric elastomers is described.
【0013】芳香族炭化水素共役ジエン系ブロック型熱
可塑性エラストマーの内部架橋の必要な程度は、ASTM D
638により測定した100 %伸び時における引張応力の増
加率が10〜1000%の範囲内となることにより知ることが
できる。この程度以上の内部架橋を施すことにより、こ
の内部架橋スチレン系熱可塑性エラストマーは、トレッ
ド部ゴムに充填された場合、マトリックス中で1μm 以
上の平均ドメイン径を有する粒子として分散することが
できる。この粒子の平均ドメイン径が1μm 未満である
と、タイヤの前記氷雪上性能が充分でない。しかし、内
部架橋反応を過剰に行うと、この平均ドメイン径が500
μm を超えるに至り、その場合は、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 required degree of internal crosslinking of the aromatic hydrocarbon conjugated diene block thermoplastic elastomer is determined by ASTM D
It can be known from the fact that the rate of increase in tensile stress at 100% elongation measured according to 638 falls within the range of 10 to 1000%. By subjecting the internal crosslinked styrene-based thermoplastic elastomer to this degree or more, when filled in the tread rubber, it can be dispersed as particles having an average domain diameter of 1 μm or more in the matrix. If the average domain diameter of the particles is less than 1 μm, the performance of the tire on ice and snow is not sufficient. However, when the internal crosslinking reaction is excessively performed, the average domain diameter becomes 500
In this case, the wear resistance of the tread using the foamed rubber is deteriorated, which is not preferable.
【0014】この内部架橋させた芳香族炭化水素共役ジ
エン系ブロック型熱可塑性エラストマーは、発泡ゴム成
分100 重量部に対して3〜100 重量部配合するのが好ま
しく、5〜40重量部の配合が更に好ましい。3重量部未
満の配合では、氷雪路面上での駆動性、制動性及び操縦
性の向上効果が小さく、100 重量部を超える配合はゴム
組成物の混練作業性を低下させる。[0014] The internally crosslinked aromatic hydrocarbon conjugated diene block thermoplastic elastomer is preferably blended in an amount of 3 to 100 parts by weight, more preferably 5 to 40 parts by weight, based on 100 parts by weight of the foamed rubber component. More preferred. If the amount is less than 3 parts by weight, the effect of improving the driving, braking and maneuverability on ice and snow roads is small, and if it exceeds 100 parts by weight, the kneading workability of the rubber composition is reduced.
【0015】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内部
架橋芳香族炭化水素共役ジエン系ブロック型熱可塑性エ
ラストマー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、
加硫促進剤を含んでよく、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, in addition to the diene rubber and the internally cross-linked aromatic hydrocarbon conjugated diene block thermoplastic elastomer, the composition disposed in the tread, other rubbers and compounding agents usually used in tread rubbers, for example, fillers Agents, anti-aging agents, vulcanizing agents,
Vulcanization accelerators may be included, and the type and amount of these are within the range usually used for tread rubber, and are not particularly limited.
【0016】本発明において、トレッドゴムが3〜35%
の発泡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 the ice surface near 0 ° C. has a lot of molten water in the vicinity of 0 ° C. This is because closed cells are indispensable.
Foaming may be carried out by a foaming agent or by high-pressure gas mixing. 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.
【0017】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。[0017] 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).
【0018】尚、本発明の空気入りタイヤにおいては、
上述の芳香族炭化水素共役ジエン系ブロック型熱可塑性
エラストマー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。Incidentally, in the pneumatic tire of the present invention,
The foamed rubber containing the above-mentioned aromatic hydrocarbon conjugated diene-based thermoplastic elastomer may be provided only in the cap portion of the tread portion having the cap-base structure.
【0019】[0019]
【実施例】以下、実施例及び比較例によってこの発明を
更に詳細に説明する。以下に示すトレッドゴムの性質及
び試験タイヤによるタイヤ性能の試験は、下記の方法で
行った。(1) トレッド部ゴム中における内部架橋芳香族
炭化水素共役ジエン系ブロック型 熱可塑性エラストマーの平均ドメイン径 サンプルから10ロットの試料を選び、光学顕微鏡の視野
内の内部架橋芳香族炭化水素共役ジエン系ブロック型熱
可塑性エラストマーのドメイン20個の直径((最長直径
+最短直径)/2により算出する)を測定し、各ロット
毎に平均ドメイン径を算出し、更に10ロットの平均ドメ
イン径の平均を算出した。 (2) 氷上摩擦係数 ゴムの氷上摩擦係数、特に0℃付近の湿潤状態における
氷上摩擦係数は、表面温度が−0.5 ℃の氷上に、試料
(試料寸法:長さ10mm、幅10mm、厚さ5mm)の表面と氷
を接触させ、協和界面科学株式会社製の動・静摩擦係数
計を用いて測定した。測定条件として荷重2kg/cm2 、
滑り速度10mm/sec 、雰囲気温度−2℃、表面状態は鏡
面に近似して行った。 (3) 氷上制動性能 試験タイヤ、乗用車用ラジアルタイヤPSR(165 SR 13)を
つくり、ならし走行として50 Km 通常走行を行った後、
テストに供した。(次の摩耗試験も同様である。)各試
験タイヤ4本を排気量1500 cc の乗用車に装着し、外気
温−5℃の氷上で制動距離を測定した。比較例1のタイ
ヤを100 として指数表示した。数値が大きい程、制動性
が良好であることを示す。 (4) 摩耗試験 各試験タイヤ2本を排気量1500 cc の乗用車のドライブ
軸に取り付け、テストコースのコンクリート路面上を所
定の速度で走行させた。溝深さの変化量を測定し、比較
例1のタイヤを100 として指数表示した。数値が大きい
程、耐摩耗性能が良好であることを示す。The present invention will be described below in more detail with reference to Examples and Comparative Examples. Tests of the properties of the tread rubber and tire performance using test tires described below were performed by the following methods. (1) Average domain diameter of internally crosslinked aromatic hydrocarbon conjugated diene block type thermoplastic elastomer in the tread rubber Select 10 lots of samples from the sample and select the internal crosslinked aromatic hydrocarbon conjugated diene system within the visual field of the optical microscope. The diameter (calculated by (longest diameter + shortest diameter) / 2) of 20 domains of the block type thermoplastic elastomer is measured, the average domain diameter is calculated for each lot, and the average of the average domain diameter of 10 lots is further calculated. Calculated. (2) Coefficient of friction on ice The coefficient of friction of rubber on ice, especially the coefficient of friction on ice in a wet state near 0 ° C, is measured on ice with a surface temperature of -0.5 ° C (sample size: length 10 mm, width 10 mm, thickness 5 mm). ) Was brought into contact with ice and measured using a dynamic / static friction coefficient meter manufactured by Kyowa Interface Science Co., Ltd. The measurement conditions were a load of 2 kg / cm 2 ,
The sliding speed was 10 mm / sec, the ambient temperature was -2 ° C, and the surface condition was similar to a mirror surface. (3) Ice braking performance Test tires, radial tires for passenger cars PSR (165 SR 13) were made, and after 50 km normal running as normal running,
Tested. (The same applies to the following abrasion tests.) Four test tires were mounted on a passenger car with a displacement of 1500 cc, and the braking distance was measured on ice at an outside temperature of -5 ° C. The index of the tire of Comparative Example 1 was set to 100 and indicated as an index. The larger the value, the better the braking performance. (4) Abrasion test Two test tires were mounted on a drive shaft of a passenger car having a displacement of 1500 cc, and the test tires were driven at a predetermined speed on a concrete road surface of a test course. The amount of change in the groove depth was measured, and the index of the tire of Comparative Example 1 was set as 100. The larger the value, the better the wear resistance performance.
【0020】実施例1〜5、比較例1〜4 S−B型芳香族炭化水素共役ジエン系ブロック型熱可塑
性エラストマーを表1に示す配合内容又は放射線照射量
で内部架橋反応を行わせ、硫黄架橋又は放射線架橋構造
を形成した。尚、AおよびBについては145 ℃加圧下で
30分間予備架橋を行なわしめた。 Examples 1 to 5 and Comparative Examples 1 to 4 The SB type aromatic hydrocarbon conjugated diene block thermoplastic elastomer was subjected to an internal crosslinking reaction at the blending content or radiation dose shown in Table 1 to obtain sulfur. A crosslinked or radiation crosslinked structure was formed. For A and B, pressurized at 145 ° C
Pre-crosslinking was performed for 30 minutes.
【0021】[0021]
【表1】 [Table 1]
【0022】サンプルA〜Dの調製は、表1に示す配合
にて混練後、145 ℃×40分加圧加硫して硫黄架橋を導入
することにより行った。上記内部架橋芳香族炭化水素共
役ジエン系ブロック型熱可塑性エラストマーを配合した
ゴム組成物及び比較のためこれを含まない発泡ゴム組成
物を表2に示す配合内容で調製し、加硫物の氷上摩擦係
数及び平均ドメイン径、発泡倍率を測定した。また、こ
れらのゴム組成物を発泡ゴムのトレッドに配設したタイ
ヤの氷上制動性能及び耐摩耗性能を測定した。結果を表
2に示す。Samples A to D were prepared by kneading with the composition shown in Table 1 and then vulcanizing under pressure at 145 ° C. for 40 minutes to introduce sulfur crosslinking. A rubber composition containing the above-mentioned internally crosslinked aromatic hydrocarbon conjugated diene-based thermoplastic elastomer and a foamed rubber composition not containing the same were prepared according to the formulation shown in Table 2 for comparison. The coefficient, average domain diameter, and expansion ratio were measured. In addition, the braking performance on ice and the abrasion resistance of a tire in which these rubber compositions were disposed on a tread of foamed rubber were measured. Table 2 shows the results.
【0023】[0023]
【表2】 [Table 2]
【0024】表2から明らかなように内部架橋を施すこ
とによって、芳香族炭化水素共役ジエン系ブロック型熱
可塑性エラストマーのゴム組成物中の平均ドメイン径を
1〜500 μm の範囲内とし、かつ発泡率を3〜35%とし
た実施例1〜2の組成物は、比較例1に示す通常の発泡
ゴムトレッドに比べて耐摩耗性能が向上し、しかもいず
れも氷上制動性能が顕著に向上している。As is apparent from Table 2, by performing internal crosslinking, the average domain diameter of the aromatic hydrocarbon conjugated diene block thermoplastic elastomer in the rubber composition is in the range of 1 to 500 μm, and foaming is carried out. The compositions of Examples 1 and 2 in which the ratio was 3 to 35% had improved abrasion resistance as compared with the ordinary foamed rubber tread shown in Comparative Example 1, and all of them had significantly improved braking performance on ice. I have.
【0025】これに対して、比較例2〜6に見られるよ
うに、芳香族炭化水素共役ジエン系ブロック型熱可塑性
エラストマーまたは発泡倍率が本発明の要件を満たして
いない場合は、タイヤの氷上制動性能と耐摩耗性の双方
を同時に改善することができないことが分かる。On the other hand, as shown in Comparative Examples 2 to 6, when the aromatic hydrocarbon conjugated diene block thermoplastic elastomer or the expansion ratio does not satisfy the requirements of the present invention, the tire is braked on ice. It can be seen that both performance and wear resistance cannot be improved simultaneously.
【0026】[0026]
【発明の効果】実施例及び比較例から明らかなように、
3〜35%の発泡率の独立気泡を有する発泡ゴムを主体と
するマトリックスゴム100 重量部に対し、100 %伸張時
における引張応力の増加率が10%〜1000となるまで内部
架橋させた、平均粒径1〜500μm のビニル芳香族炭化
水素共役ジエン系ブロック型熱可塑性エラストマーを3
〜100 重量部配合してなるゴム組成物をトレッドに配設
した空気入りタイヤは、耐摩耗性を低下させることなく
湿潤状態及び乾燥状態にある氷雪路面上での駆動性、制
動性及び操縦性を顕著に向上させることができる。As is clear from the examples and comparative examples,
An average of 100 parts by weight of a matrix rubber mainly composed of foamed rubber having closed cells having a foaming ratio of 3 to 35%, and an internal crosslink was performed until the rate of increase in tensile stress at 100% elongation became 10% to 1000. A block of a vinyl aromatic hydrocarbon conjugated diene-based thermoplastic elastomer having a particle size of 1 to 500 μm
A pneumatic tire in which a rubber composition containing up to 100 parts by weight is disposed on a tread has excellent drivability, braking performance and maneuverability on ice and snowy road surfaces in wet and dry conditions without reducing wear resistance. Can be significantly improved.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−89547(JP,A) 特開 平1−297303(JP,A) 特開 平1−118542(JP,A) 特開 昭59−4634(JP,A) 特開 平2−24334(JP,A) 特開 平3−103454(JP,A) (58)調査した分野(Int.Cl.7,DB名) B60C 11/00 B60C 1/00 B60C 11/14 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-89547 (JP, A) JP-A-1-297303 (JP, A) JP-A-1-118542 (JP, A) JP-A-59-1985 4634 (JP, A) JP-A-2-24334 (JP, A) JP-A-3-103454 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B60C 11/00 B60C 1 / 00 B60C 11/14
Claims (2)
10〜1000%の範囲内となるまで内部架橋させた、平均粒
径1〜500 μmのビニル芳香族炭化水素共役ジエンブロ
ック型熱可塑性エラストマーをゴム分100 重量部に対し
3〜100 重量部含有し、かつ3〜35%の発泡率の独立気
泡を有する発泡ゴムをトレッドに配設したことを特徴と
する空気入りタイヤ。1. The rate of increase in tensile stress at 100% elongation is
It contains 3 to 100 parts by weight of a vinyl aromatic hydrocarbon conjugated diene block type thermoplastic elastomer having an average particle diameter of 1 to 500 μm, which is internally cross-linked to a range of 10 to 1000%, based on 100 parts by weight of rubber. A pneumatic tire, wherein a foamed rubber having closed cells having a foaming ratio of 3 to 35% is provided in a tread.
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. A pneumatic tire, wherein the rubber composition according to claim 1 is provided on a cap portion of a tread portion having a cap-base structure.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3171979A JP3054238B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3171979A JP3054238B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04368204A JPH04368204A (en) | 1992-12-21 |
JP3054238B2 true JP3054238B2 (en) | 2000-06-19 |
Family
ID=15933290
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3171979A Expired - Fee Related JP3054238B2 (en) | 1991-06-18 | 1991-06-18 | Pneumatic tire |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3054238B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6632885B2 (en) | 1999-04-13 | 2003-10-14 | Mitsui Chemicals, Inc. | Soft syndiotactic polypropylene composition and molded product |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2984225B1 (en) * | 2011-12-16 | 2014-04-25 | Michelin Soc Tech | PNEUMATIC BANDAGE WITH A TREAD COMPRISING AN IMPREGNATED FELT |
-
1991
- 1991-06-18 JP JP3171979A patent/JP3054238B2/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6632885B2 (en) | 1999-04-13 | 2003-10-14 | Mitsui Chemicals, Inc. | Soft syndiotactic polypropylene composition and molded product |
Also Published As
Publication number | Publication date |
---|---|
JPH04368204A (en) | 1992-12-21 |
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