JP2004308024A - Organic fiber cord for reinforcing rubber and tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic fiber cord for reinforcing rubber having strength and fatigue resistance balanced at a high level. <P>SOLUTION: The organic fiber cord for reinforcing the rubber is composed of a plied yarn prepared by applying first twists to fiber raw yarns composed of a polyketone at a first twist multiplier N<SB>1</SB>, then doubling the plurality of first twisted yarns and subsequently applying final twists in the direction opposite to that of the first twists at a final twist multiplier N<SB>2</SB>. The first twist multiplier N<SB>1</SB>and the final twist multiplier N<SB>2</SB>satisfy formula (IV) represented by (D<SB>2</SB>/D<SB>1</SB>)<SP>1/2</SP><N<SB>2</SB>/N<SB>1</SB>≤4.25, formula (II) represented by N<SB>1</SB>=n<SB>1</SB>×(0.139×D<SB>1</SB>/ρ)<SP>1/2</SP>×10<SP>-3</SP>and formula (III) represented by N<SB>2</SB>=n<SB>2</SB>×(0.139×D<SB>2</SB>/ρ)<SP>1/2</SP>×10<SP>-3</SP>[wherein, n<SB>1</SB>is the number of the first twists (turns/10 cm); n<SB>2</SB>is the number of the final twists (turns/10 cm); D<SB>1</SB>is the nominal denier of the first twisted yarns; D<SB>2</SB>is the total nominal denier; and ρis the specific gravity (g/cm<SP>3</SP>) of the polyketone fiber]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

（式中、Ａはエチレン性結合によって重合されたエチレン性不飽和化合物由来の部分であり、各繰り返し単位において同一でも異なっていてもよい）
で表される繰り返し単位から実質的になるポリケトンの繊維原糸に、下記式（ＩＩ）で定義される下撚り係数Ｎ_１で下撚りをかけた後、該下撚り糸複数本を引き揃えて下撚りと逆方向に、下記式（ＩＩＩ）で定義される上撚り係数Ｎ_２で上撚りをかけた双撚糸よりなり、前記下撚り係数Ｎ_１と前記上撚り係数Ｎ_２とが下記式（ＩＶ）を満たすことを特徴とする。
Ｎ_１＝ｎ_１×（０．１３９×Ｄ_１／ρ）^１／２×１０^−３ ・・・ （ＩＩ）
Ｎ_２＝ｎ_２×（０．１３９×Ｄ_２／ρ）^１／２×１０^−３ ・・・ （ＩＩＩ）
（Ｄ_２／Ｄ_１）^１／２ ＜ Ｎ_２／Ｎ_１ ≦ ４．２５ ・・・ （ＩＶ）
（式（ＩＩ）、（ＩＩＩ）及び（ＩＶ）において、ｎ_１は下撚り数（回／１０ｃｍ）で；ｎ_２は上撚り数（回／１０ｃｍ）で；Ｄ_１は下撚り糸の表示デニールで；Ｄ_２はトータル表示デニールで；ρは上記ポリケトン繊維の比重（ｇ／ｃｍ^３）である。）
【０００９】
本発明のゴム補強用有機繊維コードの好適例においては、前記下撚り係数Ｎ_１と前記上撚り係数Ｎ_２とが下記式（Ｖ）を満たす。
１．４５ ≦ Ｎ_２／Ｎ_１ ≦ ４．２５ ・・・ （Ｖ）
（式中、Ｎ_１及びＮ_２は上記と同義である。）
【００１０】
本発明のゴム補強用有機繊維コードの他の好適例においては、前記式（Ｉ）中のＡがエチレン基である。
【００１１】
また、本発明のタイヤは、上記ゴム補強用有機繊維コードをタイヤの何れかの部材に用いたことを特徴とする。
【００１２】
本発明のタイヤの好適例においては、前記タイヤの部材が、カーカス、ベルト補強層及びベルトの少なくとも何れかである。
【００１３】
【発明の実施の形態】
以下に、本発明を詳細に説明する。本発明のゴム補強用有機繊維コードは、上記式（Ｉ）で表される繰り返し単位から実質的になるポリケトン（ＰＫ）繊維原糸に、上記式（ＩＩ）で定義される下撚り係数Ｎ_１で下撚りをかけた後、該下撚り糸複数本を引き揃えて下撚りと逆方向に、上記式（ＩＩＩ）で定義される上撚り係数Ｎ_２で上撚りをかけた双撚糸よりなり、前記下撚り係数Ｎ_１と前記上撚り係数Ｎ_２とが上記式（ＩＶ）を満たすことを特徴とする。本発明のコードにおいては、ＰＫ繊維を用いることで、芳香族ポリアミド繊維（アラミド繊維）を用いたコードに比べて耐疲労性を向上させ、更に、式（ＩＶ）を満たす撚り構造とすることで、バランス撚りを採用したコードに比べて同等の耐疲労性を維持しつつ、コードの破断強力を向上させ、その結果、コードの強度と耐疲労性とが高度にバランスされている。
【００１４】
本発明のゴム補強用有機繊維コードの繊維原糸は、上記式（Ｉ）で表される繰り返し単位から実質的になるポリケトンを原料とする。該ポリケトンは、分子中にＣＯ単位（カルボニル基）とエチレン性不飽和化合物由来の単位とが配列された交互共重合体、即ち、高分子鎖中で各ＣＯ単位の隣に、例えばエチレン単位等のオレフィン単位が一つずつ位置する構造である。また、該ポリケトンは、一酸化炭素と特定のエチレン性不飽和化合物一種との共重合体であってもよく、一酸化炭素とエチレン性不飽和化合物二種以上との共重合体であってもよい。式（Ｉ）中のＡを形成するエチレン性不飽和化合物としては、エチレン，プロピレン，ブテン，ペンテン，ヘキセン，ヘプテン，オクテン，ノネン，デセン，ドデセン，スチレン等の不飽和炭化水素化合物、メチルアクリレート，メチルメタクリレート，ビニルアセテート，ウンデセン酸等の不飽和カルボン酸又はその誘導体、更にはウンデセノール，６−クロロヘキセン，Ｎ−ビニルピロリドン，及びスルニルホスホン酸のジエチルエステル等が挙げられる。これらは単独で用いてもよく、二種以上を組み合わせて用いてもよいが、特にポリマーの力学特性や耐熱性等の点から、エチレン性不飽和化合物としてエチレンを主体とするものを用いたポリケトンが好ましい。
【００１５】
エチレンと他のエチレン性不飽和化合物とを併用する場合、エチレンは、全エチレン性不飽和化合物に対し、８０モル％以上になるように用いるのが好ましい。８０モル％未満では得られるポリマーの融点が２００℃以下になり、得られる有機繊維コードの耐熱性が不充分となる場合がある。有機繊維コードの力学特性や耐熱性の点から、エチレンの使用量は、特に全エチレン性不飽和化合物に対し９０モル％以上が好ましい。前記のポリケトンは、公知の方法、例えばヨーロッパ特許公開第１２１９６５号，同第２１３６７１号，同第２２９４０８号及び米国特許第３９１４３９１号明細書に記載された方法に従って製造することができる。
【００１６】
本発明のゴム補強用有機繊維コードに用いられるポリケトンの重合度は、ｍ−クレゾール中、６０℃で測定した溶液粘度が１．０〜１０．０ｄＬ／ｇの範囲にあるのが好ましい。溶液粘度が１．０ｄＬ／ｇ未満では、得られる有機繊維コードの力学強度が不充分となる場合があり、コードの力学強度の観点から、溶液粘度が１．２ｄＬ／ｇ以上であるのが更に好ましい。一方、溶液粘度が１０．０ｄＬ／ｇを超えると、繊維化時の溶融粘度や溶液粘度が高くなりすぎて紡糸性が不良となる場合があり、紡糸性の観点から、溶液粘度が５．０ｄＬ／ｇ以下であるのが更に好ましい。繊維の力学強度及び紡糸性などを考慮すると、溶液粘度は１．３〜４．０ｄＬ／ｇの範囲が特に好ましい。
【００１７】
上記ポリケトンの繊維化方法は、特に限定されないが、一般的には溶融紡糸法又は溶液紡糸法が採用される。溶融紡糸法を採用する場合には、例えば特開平１−１２４６１７号公報に記載の方法に従って、ポリマーを通常、融点より２０℃以上高い温度、好ましくは融点より４０℃程度高い温度で溶融紡糸し、次いで、通常、融点より１０℃以下低い温度、好ましくは融点より４０℃程度低い温度において、好ましくは３倍以上の延伸比で、更に好ましくは７倍以上の延伸比で延伸処理することにより、容易に所望の繊維を得ることができる。
【００１８】
一方、溶液紡糸法を採用する場合、例えば特開平２−１１２４１３号公報に記載の方法に従って、ポリマーを例えばヘキサフルオロイソプロパノール，ｍ−クレゾール等に０．２５〜２０質量％、好ましくは０．５〜１０質量％の濃度で溶解させ、紡糸ノズルより押し出して繊維化し、次いでトルエン，エタノール，イソプロパノール，ｎ−ヘキサン，イソオクタン，アセトン，メチルエチルケトン等の非溶剤浴、好ましくはアセトン浴中で溶剤を除去、洗浄して紡糸原糸を得、さらに（融点−１００℃）〜（融点＋１０℃）、好ましくは（融点−５０℃）〜（融点）の範囲の温度で延伸処理することにより、所望のフィラメントを得ることができる。また、このポリケトンには、熱，酸素等に対して十分な耐久性を付与する目的で酸化防止剤を加えることが好ましく、また必要に応じて艶消し剤，顔料，帯電防止剤等も配合することができる。
【００１９】
本発明のコードは、下撚り係数Ｎ_１と上撚り係数Ｎ_２とが、上記式（ＩＶ）を満たすことを要し、式（Ｖ）を満たすのが好ましい。上記式（ＩＶ）において、Ｎ_２／Ｎ_１が４．２５を超えると、コードの引張剛性が向上するものの、耐疲労性が低下し、（Ｄ_２／Ｄ_１）^１／２以下ではコードの引張剛性の改善効果が見られず、バランス撚りを採用したコードに比べコード強度を向上させることができない。コードの引張剛性を更に改善する観点からは、Ｎ_２／Ｎ_１が１．４５以上であるのが好ましく、１．７３を超えるのが更に好ましい。
【００２０】
本発明のゴム補強用有機繊維コードの製造においては、上記ポリケトンよりなる繊維（ＰＫ繊維）を原糸として、上記式（ＩＶ）を満たすように下撚りと上撚りをかける限り特に制限はない。ここで、上記ポリケトン繊維は、耐疲労性、強力及び耐熱接着性に優れるため、コード径を小さくすることができ、その結果、該コードを用いたゴム部材の軽量化を達成することができる。
【００２１】
上記ゴム補強用有機繊維コードにコーティングゴムを被覆するに際しては、該コードとコーティングゴムとの接着性を確保するために、該コードに、通常接着剤付与処理と熱処理を施す。具体的には、上記コードに、例えば、（１）トリアリルシアヌレートとレゾルシンとホルムアルデヒドとアンモニア水から生成する通常Ｎ３と呼称される液とＲＦＬ（レゾルシン−ホルムアルデヒド−ラテックス）液の混合液で処理する一浴型の処理方法、（２）ｐ−クロルフェノールとホルマリンとから生成する２，６−ビス（２’，４’−ジヒドロキシフェニルメチル）−４−クロルフェノールを主成分とする反応生成物とレゾルシンとホルマリンとアンモニア水とからなる通称ＰＥＸＵＬと呼称される液をＲＦＬ液と混合した液で処理する一浴型の処理方法、（３）特開昭６０−７２９７２号公報で開示されているように多価フェノールポリサルファイドと、レゾルシン及びホルマリンの縮合物とをアルカリ下で熟成した液とＲＦＬ液とを混合した液で処理する一浴型の処理方法、あるいは、（４）上記コードをエポキシ化合物又はブロックイソシアネート化合物を含む第一液で処理した後、レゾルシンとホルムアルデヒドと各種ラテックスと苛性ソーダ及び／又はアンモニア水を含む第二液（ＲＦＬ液）で処理する二浴型の処理方法などにより、接着剤付与処理を施す。
【００２２】
次いで、このようにして接着剤付与処理が施されたコードに、乾燥ゾーンの処理温度を１７０℃程度、処理時間を６０〜１６０秒間程度とし、またヒートセットゾーン及びノルマライジングゾーンの処理温度を２４０〜２７０℃程度、処理時間を６０〜１６０秒間とし、更にヒートセットゾーンコード張力を、好ましくは３．５〜９．７ｍＮ／ｄｔｅｘ（コードで、１１．５〜３１．８Ｎ／コード）、ノルマライジングゾーンコード張力を、好ましくは０．２６〜４．４ｍＮ／ｄｔｅｘ（コードで、０．８８〜１４．６Ｎ／コード）の範囲に設定して、熱処理を施す。
【００２３】
本発明のタイヤは、上記ゴム補強用有機繊維コードをタイヤの何れかの部材に用いたことを特徴とし、ここで、該タイヤ部材としては、カーカス、ベルト補強層及びベルトが挙げられる。上記ゴム補強用有機繊維コードは、初期の剛性が向上しているため、該コードをタイヤのカーカスに用いることにより、タイヤのサイド部の剛性を向上させることができる。
【００２４】
次に本発明のタイヤの実施態様を図面に基づき説明する。図１は、本発明の空気入りタイヤの一実施態様を示す断面図である。図１に示すタイヤは、一対のビード部１と、一対のサイド部２と、トレッド部３と、該ビード部１に埋設されたビードコア４間にトロイド状に延在させたカーカス５と、該カーカス５のクラウン部でタイヤ径方向外側に配した少なくとも二枚のベルト層からなるベルト６と、該ベルト６のタイヤ径方向外側でベルト６の全体を覆うように配置したベルト補強層７Ａと、該ベルト補強層７Ａのタイヤ径方向外側でベルト６の両端部を覆うように配置した一対のベルト補強層７Ｂとからなる。図示例のベルト補強層７Ａ，７Ｂは、夫々一層であるが、二層以上であってもよい。また、ベルト補強層７Ａ及び／又はベルト補強層７Ｂが省略されたタイヤも、本発明のタイヤの一例である。ここで、本発明のタイヤにおいては、カーカス５、ベルト補強層７Ａ，７Ｂ及びベルト６の少なくとも何れかに、上述したポリケトン繊維からなるコードを適用するのが好ましい。
【００２５】
【実施例】
以下に、実施例を挙げて本発明を更に詳しく説明するが、 本発明は下記の実施例に何ら限定されるものではない。
【００２６】
表１に示す構造のゴム補強用有機繊維コードを試作し、該コードの強力と耐疲労性を下記の方法で評価した。ここで、ポリケトン繊維（ＰＫ繊維）としては、式（Ｉ）のＡがエチレン基のものを使用した。
【００２７】
（１）コード強力
上記ゴム補強用有機繊維コードの強力を、ＪＩＳ Ｌ１０１７に準拠して測定し、比較例１を１００として指数表示した。指数値が大きい程、コードの強力が強く、良好であることを示す。
【００２８】
（２）耐疲労性
上記ゴム補強用有機繊維コードの耐疲労性を、ＪＩＳ Ｌ１０１７［チューブ疲労強さＡ法（グッドイヤ法）］に準拠して評価し、比較例１を１００として指数表示した。指数値が大きい程、コードの耐疲労性が高く、良好であることを示す。
【００２９】
【表１】

【００３０】
上記実施例及び比較例では、コードが２本撚り構造であるため、（Ｄ_２／Ｄ_１）^１／２は２^１／２（約１．４１）である。表１の結果から、繊維原糸としてポリケトン繊維（ＰＫ繊維）を採用し、Ｎ_２／Ｎ_１を４．２５以下且つ１．４５以上とすることで、比較例１に比べてコードの強力を維持しつつ、コードの耐疲労性を向上させることができる。また、Ｎ_２／Ｎ_１を１．７３を超える値とすることで、コードの強力を更に高くすることができる。
【００３１】
【発明の効果】
本発明によれば、原糸として特定のポリケトン繊維（ＰＫ繊維）を用い、更に、下撚りと上撚りのバランスを特定の範囲に規定することで、強度と耐疲労性とを高度にバランスさせたゴム補強用有機繊維コードを提供することができる。
【図面の簡単な説明】
【図１】本発明の空気入りタイヤの一実施態様を示す断面図である。
【符号の説明】
１ ビード部
２ サイド部
３ トレッド部
４ ビードコア
５ カーカス
６ ベルト
７Ａ，７Ｂ ベルト補強層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic fiber cord for rubber reinforcement and a tire using the same, and more particularly to an organic fiber cord for rubber reinforcement in which strength and fatigue resistance are highly balanced.
[0002]
[Prior art]
Conventionally, an organic fiber cord used to reinforce a rubber member such as a carcass of a tire is generally formed by twisting a fiber yarn to form a twisted yarn, and a plurality of the twisted yarns. It consists of twin-twisted yarn. Here, at present, a balanced twist in which the number of ply twists in the case of priming is equal to the number of ply twists in the case of the ply twist is generally adopted.
[0003]
The above-mentioned organic fiber cord is required to have high rigidity in itself because the original purpose is to reinforce the rubber member. On the other hand, in the case of organic fiber cords employing general-purpose balanced twisting, although the rigidity of the cord can be improved by reducing the number of twists, the fatigue resistance of the cord decreases when the number of twists is reduced. However, as a result, there is a problem that the durability of the cord is reduced.
[0004]
On the other hand, a method of adopting a high-strength aromatic polyamide fiber as a raw yarn and improving the poor compression fatigue resistance, which is a drawback of the aromatic polyamide fiber, by changing the balance between the ply twist and the ply twist is known. However, there is still room for improvement in the fatigue resistance of the cord produced by such a method (see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 63-19581
[Problems to be solved by the invention]
Then, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide an organic fiber cord for rubber reinforcement in which strength and fatigue resistance are highly balanced. Another object of the present invention is to provide a tire using the organic fiber cord.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor has found that a specific polyketone fiber (PK fiber) is used as a raw yarn of an organic fiber cord, and that the balance between the twisting and the twisting of the cord is specified. It has been found that by defining the content within the range, the strength and fatigue resistance of the organic fiber cord can be highly balanced, and the present invention has been completed.
[0008]
That is, the rubber reinforcing organic fiber cord of the present invention has the following formula (I):
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(In the formula, A is a portion derived from an ethylenically unsaturated compound polymerized by an ethylenic bond, and may be the same or different in each repeating unit.)
Is applied to the fiber raw yarn of polyketone substantially consisting of a repeating unit represented by the following formula (II), and then a plurality of the _primary twisted yarns are aligned. twisted in the opposite direction, consist of twin twisted with twisting on the second twist by a factor N _2, as defined by the following formula (III), wherein the twist factor N ₂ and the following formulas the factor N ₁ twist the lower (IV ) Is satisfied.
N ₁ = n ₁ × (0.139 × D ₁ / ρ) ^1/2 × 10 ^-3 (II)
N ₂ = n ₂ × (0.139 × D ₂ / ρ) ^1/2 × 10 ^-3 (III)
(D ₂ / D ₁ ) ^1/2 <N ₂ / N ₁ ≦ 4.25 (IV)
(In the formula (II), (III) and (IV), _{n 1} is the number of first twists (times / 10cm); _{n 2} is the number of final twists (times / 10cm); _{D 1} denotes a display denier twist yarn ; _{D 2} is a total deniers; [rho is the polyketone fiber density (g / cm ^3)).
[0009]
In a preferable embodiment of the rubber reinforcing organic fiber cord of the present invention, the lower twist factor N ₁ and the coefficient N ₂ twist on the satisfies the following formula (V).
1.45 ≦ N ₂ / N ₁ ≦ 4.25 (V)
(Wherein, N ₁ and N ₂ have the same meanings as above.)
[0010]
In another preferred embodiment of the rubber reinforcing organic fiber cord of the present invention, A in the formula (I) is an ethylene group.
[0011]
Further, the tire of the present invention is characterized in that the rubber reinforcing organic fiber cord is used for any member of the tire.
[0012]
In a preferred example of the tire of the present invention, the member of the tire is at least one of a carcass, a belt reinforcing layer, and a belt.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. The organic fiber cord for rubber reinforcement of the present invention comprises a polyketone (PK) fiber raw yarn substantially consisting of a repeating unit represented by the above formula (I), and a ply twist coefficient N ₁ defined by the above formula (II). in after twisted under the twist direction opposite aligned pull the lower yarn plurality consists of twin twisted with twisting on the second twist by a factor N _2, which is defined by the formula (III), wherein a coefficient N ₂ twist on the twist coefficient N ₁ and is characterized by satisfying the above formula (IV). In the cord of the present invention, by using the PK fiber, the fatigue resistance is improved as compared with the cord using the aromatic polyamide fiber (aramid fiber), and the twisted structure that satisfies the formula (IV) is obtained. As a result, the breaking strength of the cord is improved while maintaining the same fatigue resistance as that of the cord employing the balanced twist, and as a result, the strength and the fatigue resistance of the cord are highly balanced.
[0014]
The raw fiber of the organic fiber cord for rubber reinforcement of the present invention is made of a polyketone substantially consisting of the repeating unit represented by the above formula (I). The polyketone is an alternating copolymer in which a CO unit (carbonyl group) and a unit derived from an ethylenically unsaturated compound are arranged in a molecule, that is, an ethylene unit or the like next to each CO unit in a polymer chain. Is a structure in which olefin units are located one by one. Further, the polyketone may be a copolymer of carbon monoxide and one specific ethylenically unsaturated compound, or a copolymer of carbon monoxide and two or more ethylenically unsaturated compounds. Good. Examples of the ethylenically unsaturated compound forming A in the formula (I) include unsaturated hydrocarbon compounds such as ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, dodecene, and styrene; methyl acrylate; Unsaturated carboxylic acids such as methyl methacrylate, vinyl acetate, undecenoic acid and the like, and derivatives thereof, further, undecenol, 6-chlorohexene, N-vinylpyrrolidone, and diethyl ester of sulfonylphosphonic acid. These may be used singly or in combination of two or more, but in particular, from the viewpoint of the mechanical properties and heat resistance of the polymer, polyketones using ethylene as the ethylenically unsaturated compound are mainly used. Is preferred.
[0015]
When ethylene is used in combination with another ethylenically unsaturated compound, it is preferable to use ethylene so as to be at least 80 mol% based on all the ethylenically unsaturated compounds. If it is less than 80 mol%, the melting point of the obtained polymer will be 200 ° C. or lower, and the heat resistance of the obtained organic fiber cord may be insufficient. From the viewpoint of the mechanical properties and heat resistance of the organic fiber cord, the amount of ethylene used is particularly preferably at least 90 mol% based on all ethylenically unsaturated compounds. The polyketone can be produced according to a known method, for example, a method described in European Patent Publications 121965, 213671, 229408 and US Pat. No. 3,914,391.
[0016]
The polymerization degree of the polyketone used for the rubber reinforcing organic fiber cord of the present invention is preferably such that the solution viscosity measured at 60 ° C. in m-cresol is in the range of 1.0 to 10.0 dL / g. When the solution viscosity is less than 1.0 dL / g, the mechanical strength of the obtained organic fiber cord may be insufficient. From the viewpoint of the mechanical strength of the cord, the solution viscosity is more preferably 1.2 dL / g or more. preferable. On the other hand, if the solution viscosity exceeds 10.0 dL / g, the melt viscosity during fiberization and the solution viscosity may be too high, resulting in poor spinnability. From the viewpoint of spinnability, the solution viscosity may be 5.0 dL. / G or less. Considering the mechanical strength and spinnability of the fiber, the solution viscosity is particularly preferably in the range of 1.3 to 4.0 dL / g.
[0017]
The method of forming the polyketone into fibers is not particularly limited, but a melt spinning method or a solution spinning method is generally employed. When employing the melt spinning method, for example, according to the method described in JP-A-1-124617, the polymer is usually melt-spun at a temperature higher than the melting point by at least 20 ° C., preferably at a temperature higher by about 40 ° C. than the melting point, Then, usually, at a temperature lower than the melting point by 10 ° C. or lower, preferably by about 40 ° C. lower than the melting point, the film is easily stretched by a stretching ratio of preferably 3 times or more, more preferably a stretching ratio of 7 times or more. The desired fiber can be obtained.
[0018]
On the other hand, when the solution spinning method is adopted, the polymer is added to, for example, hexafluoroisopropanol, m-cresol or the like in an amount of 0.25 to 20% by mass, preferably 0.5 to 20% according to the method described in JP-A-2-112413. It is dissolved at a concentration of 10% by mass, extruded from a spinning nozzle to form a fiber, and then the solvent is removed and washed in a non-solvent bath such as toluene, ethanol, isopropanol, n-hexane, isooctane, acetone, methyl ethyl ketone, preferably an acetone bath. To obtain a desired filament by performing a drawing treatment at a temperature in the range of (melting point -100 ° C) to (melting point + 10 ° C), preferably (melting point -50 ° C) to (melting point). be able to. Further, it is preferable to add an antioxidant to the polyketone for the purpose of imparting sufficient durability to heat, oxygen and the like, and if necessary, a matting agent, a pigment, an antistatic agent and the like. be able to.
[0019]
Code of the present invention, the coefficient N ₂ ply-twisted and a coefficient N ₁ twist is required to satisfy the above formula (IV), preferably satisfies the formula (V). In the above formula (IV), when N ₂ / N ₁ exceeds 4.25, the tensile stiffness of the cord is improved, but the fatigue resistance is reduced, and when (D ₂ / D ₁ ) ^1/2 or less, the cord is not deformed. The effect of improving the tensile rigidity is not seen, and the cord strength cannot be improved as compared with the cord employing the balanced twist. From the viewpoint of further improving the tensile rigidity of the cord, N ₂ / N ₁ is preferably 1.45 or more, and more preferably more than 1.73.
[0020]
In the production of the organic fiber cord for rubber reinforcement of the present invention, there is no particular limitation as long as a fiber (PK fiber) made of the above-mentioned polyketone is used as a raw yarn and subjected to the first twist and the first twist so as to satisfy the above formula (IV). Here, since the polyketone fiber is excellent in fatigue resistance, strength, and heat resistance, the cord diameter can be reduced, and as a result, the weight of the rubber member using the cord can be reduced.
[0021]
When coating the rubber reinforcing organic fiber cord with the coating rubber, the cord is usually subjected to an adhesive application treatment and a heat treatment in order to secure the adhesiveness between the cord and the coating rubber. Specifically, the above code is treated with, for example, a mixture of (1) a liquid generally called N3 generated from triallyl cyanurate, resorcin, formaldehyde, and aqueous ammonia and an RFL (resorcin-formaldehyde-latex) liquid. (2) A reaction product mainly composed of 2,6-bis (2 ', 4'-dihydroxyphenylmethyl) -4-chlorophenol formed from p-chlorophenol and formalin One-bath treatment method in which a solution called PEXUL, which is commonly called PEXUL, which is composed of urea, resorcin, formalin, and ammonia water, is treated with a solution mixed with an RFL solution, (3) disclosed in JP-A-60-72972. A polyhydric phenol polysulfide and a condensate of resorcinol and formalin under alkaline conditions and an RFL solution A one-bath treatment method of treating with a mixed solution, or (4) treating the above cord with a first solution containing an epoxy compound or a blocked isocyanate compound, and then resorcinol, formaldehyde, various latexes, caustic soda and / or ammonia water Is applied by a two-bath processing method of processing with a second liquid (RFL liquid) containing
[0022]
Next, the cord subjected to the adhesive application treatment in this manner was treated at a treatment temperature of the drying zone of about 170 ° C., a treatment time of about 60 to 160 seconds, and a treatment temperature of the heat setting zone and the normalizing zone of 240 ° C. To 270 ° C., the treatment time is 60 to 160 seconds, and the heat set zone cord tension is preferably 3.5 to 9.7 mN / dtex (11.5 to 31.8 N / cord in cord), and normalizing. The heat treatment is performed by setting the zone cord tension preferably in the range of 0.26 to 4.4 mN / dtex (0.88 to 14.6 N / cord in cord).
[0023]
The tire of the present invention is characterized in that the above-mentioned rubber reinforcing organic fiber cord is used for any member of the tire, and the tire member includes a carcass, a belt reinforcing layer, and a belt. Since the rubber reinforcing organic fiber cord has an improved initial rigidity, the rigidity of the side portion of the tire can be improved by using the cord for a tire carcass.
[0024]
Next, an embodiment of the tire of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the pneumatic tire of the present invention. The tire shown in FIG. 1 includes a pair of bead portions 1, a pair of side portions 2, a tread portion 3, a carcass 5 extended in a toroidal shape between bead cores 4 embedded in the bead portion 1, A belt 6 composed of at least two belt layers disposed radially outward at the crown portion of the carcass 5, a belt reinforcing layer 7A disposed so as to cover the entire belt 6 radially outward of the belt 6; It comprises a pair of belt reinforcing layers 7B arranged so as to cover both ends of the belt 6 on the outer side in the tire radial direction of the belt reinforcing layer 7A. The illustrated belt reinforcing layers 7A and 7B are each a single layer, but may be two or more layers. Further, a tire in which the belt reinforcing layer 7A and / or the belt reinforcing layer 7B is omitted is also an example of the tire of the present invention. Here, in the tire of the present invention, it is preferable to apply the cord made of the above-described polyketone fiber to at least one of the carcass 5, the belt reinforcing layers 7A and 7B, and the belt 6.
[0025]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
[0026]
An organic fiber cord for rubber reinforcement having a structure shown in Table 1 was experimentally produced, and the strength and fatigue resistance of the cord were evaluated by the following methods. Here, as the polyketone fiber (PK fiber), one in which A in the formula (I) was an ethylene group was used.
[0027]
(1) Cord Strength The strength of the organic fiber cord for rubber reinforcement was measured according to JIS L1017, and the index was indicated as an index with Comparative Example 1 being 100. The larger the index value is, the stronger and better the code is.
[0028]
(2) Fatigue Resistance The fatigue resistance of the rubber reinforcing organic fiber cord was evaluated according to JIS L1017 [tube fatigue strength A method (good ear method)]. The larger the index value, the higher and better the fatigue resistance of the cord.
[0029]
[Table 1]

[0030]
In the above Examples and Comparative Examples, (D ₂ / D ₁ ) ^1/2 is 2 ^1/2 (about 1.41) because the cord has a two-strand structure. From the results in Table 1, by using a polyketone fiber (PK fiber) as the fibrous fiber and setting N ₂ / N ₁ to 4.25 or less and 1.45 or more, the cord strength was higher than that of Comparative Example 1. The fatigue resistance of the cord can be improved while maintaining it. By setting N ₂ / N ₁ to a value exceeding 1.73, the strength of the code can be further increased.
[0031]
【The invention's effect】
According to the present invention, strength and fatigue resistance are highly balanced by using a specific polyketone fiber (PK fiber) as a raw yarn, and further defining the balance between ply twist and ply twist in a specific range. The present invention can provide an organic fiber cord for rubber reinforcement.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a pneumatic tire according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bead part 2 Side part 3 Tread part 4 Bead core 5 Carcass 6 Belt 7A, 7B Belt reinforcement layer

Claims (5)

The following formula (I):

(In the formula, A is a portion derived from an ethylenically unsaturated compound polymerized by an ethylenic bond, and may be the same or different in each repeating unit.)
Is applied to the fiber raw yarn of polyketone substantially consisting of a repeating unit represented by the following formula (II), and then a plurality of the _primary twisted yarns are aligned. twisted in the opposite direction, consist of twin twisted with twisting on the second twist by a factor N _2, as defined by the following formula (III), wherein the twist factor N ₂ and the following formulas the factor N ₁ twist the lower (IV An organic fiber cord for rubber reinforcement characterized by satisfying (1).
N ₁ = n ₁ × (0.139 × D ₁ / ρ) ^1/2 × 10 ^-3 (II)
N ₂ = n ₂ × (0.139 × D ₂ / ρ) ^1/2 × 10 ^-3 (III)
(D ₂ / D ₁ ) ^1/2 <N ₂ / N ₁ ≦ 4.25 (IV)
(In the formula (II), (III) and (IV), _{n 1} is the number of first twists (times / 10cm); _{n 2} is the number of final twists (times / 10cm); _{D 1} denotes a display denier twist yarn ; _{D 2} is a total deniers; [rho is the polyketone fiber density (g / cm ^3)). Rubber reinforcing organic fiber cord according to claim 1 in which the coefficient N ₂ twist on the coefficient N ₁ twist under the is characterized by satisfying the following formula (V).
1.45 ≦ N ₂ / N ₁ ≦ 4.25 (V)
(Wherein, N ₁ and N ₂ have the same meanings as above.) The organic fiber cord for rubber reinforcement according to claim 1, wherein A in the formula (I) is an ethylene group. A tire, wherein the rubber reinforcing organic fiber cord according to any one of claims 1 to 3 is used for any member of a tire. The tire according to claim 4, wherein the member of the tire is at least one of a carcass, a belt reinforcing layer, and a belt.

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