JP3616795B2 - Aramid fiber cord for hose reinforcement and hose using the same - Google Patents

Description

【００１１】
また第２発明は、「（請求項２） 内面ゴム層と外面ゴム層との間にアラミド繊維コードからなる補強層を有する繊維補強ゴムホースにおいて、該アラミド繊維コードが、予備撚りを施した後に、予備撚りと同一方向に撚糸を行ったアラミド繊維に、ポリエポキシド化合物、ブロックドポリイソシアネート化合物及びポリブタジエンゴムラテックスからなる第１処理剤が被覆され、次いでレゾルシン・フォルマリン・ニトリル・ブタジエンゴムラテックス（ＲＦＬ）に、パラクロロフェノールとレゾルシンとをフォルムアルデヒドで共縮合した化合物であって下記式（化４）で表される、３核体 (Ｉ) 、５核体(II)、及び７核体 (III)を主成分とするクロロフェノール化合物を配合し、さらに平滑成分として四フッ化ポリエチレン微粒子の水分散体を、ＲＦＬとクロロフェノール化合物の合計の固形分に対して５〜２０重量％配合した第２処理剤が被覆されたアラミド繊維コードであることを特徴とする繊維補強ゴムホース。」である。
【００１２】
【化４】

【００１３】
本発明でいうアラミド繊維とは、芳香族ジカルボン酸と芳香族ジアミン、又は芳香族アミノカルボン酸から構成されるポリアミド、及びこれらの共重合ポリアミドからなる繊維であるが、特に強度及び弾性率に優れていてホース補強効果が高いことから、ポリ−ｐ−フェニレンテレフタルアミド繊維、コポリ−ｐ−フェニレン−（３、４’−オキシジフェニル）テレフタルアミド繊維（例えば帝人（株）製：テクノ−ラ）等のパラ配向型アラミド繊維が好ましい。
【００１４】
かかるアラミド繊維の単繊維繊度については特に限定する必要はないが、小さすぎると製造上のトラブルが発生しやすく、また補強効果も不充分となりやすい。一方、アラミド繊維は一般に湿式紡糸されるために、太繊度のものは安定に製造することが困難となる。したがって、通常は０．５〜５デニ−ル、好ましくは１〜３デニ−ルのものが用いられる。またアラミド繊維束の総繊度は５００〜２０００デニ−ル程度のものが用いられ、この範囲外では後述する予備撚りの効果が小さくなる傾向がある。
【００１５】
本発明においては、上記のアラミド繊維にはまず予備撚りを施した後に、該予備撚りを施した繊維束を複数本、好ましくは２本合糸してさらに撚糸をすることが必要である。ここで、撚糸方向は予備撚りと同一方向とすることが、ホース金具取りつけのために補強繊維層がかしめられた際に、その応力をうまく分散させてコード破断を発生し難くする（以下単にかしめ性良と称することがある）上で必要である。
【００１６】
予備撚りの撚り数は、１０ｃｍ当たり、２〜５回、特に４回程度が好ましく、２回未満では単繊維の引き揃えが小さくなってかしめ性が低下し、一方５回を越えると撚糸後の強度が低下する傾向がある。
【００１７】
一方合糸した後の撚糸の撚り数は、１０ｃｍ当たり３〜１５回、好ましくは５〜１０回とする。
【００１８】
次に第１処理剤に使用するポリエポキシド化合物は、１分子中に少なくとも２個以上のエポキシ基を該化合物１００ｇ当たり０．２ｇ当量以上含有する化合物である。エチレングリコール、グリセロール、ソルビトール、ペンタエリスリトール、ポリエチレングリコール等の多価アルコール類とエピクロルヒドリンの如きハロゲン含有エポキシド類との反応生成物、レゾルシン・ビス（４−ヒドロキシフェニル）ジメチルメタン、フェノール・ホルムアルデヒド樹脂、レゾルシン・ホルムアルデヒド樹脂等の多価フェノール類と前記ハロゲン含有エポキシド類との反応生成物、過酢酸または過酸化水素等で不飽和化合物を酸化して得られるポリエポキシド化合物などであり、具体例としては、３，４−エポキシシクロヘキセンエポキシド、３，４−エポキシシクロヘキセンメチル−３，４−エポキシシクロヘキセンカルボキシレート、ビス（３，４−エポキシ−６メチル−シクロヘキシルメチル）アジペートなどを挙げることが出来る。これらの内、特に多価アルコールとエピクロルヒドリンとの反応生成物、即ち多価アルコールのポリグリシジルエーテル化合物が優れた性能を発現するので好ましい。
【００１９】
かかるポリエポキシド化合物は、通常乳化液として使用する。乳化液または溶液とするには、例えばかかるポリエポキシド化合物をそのまま、あるいは必要に応じて少量の溶媒に溶解したものを、公知の乳化剤、例えばアルキルベンゼンスルフォン酸ソーダ、ジオクチルスルフォサクシネートナトリウム塩、ノニルフェノールエチレンオキサイド付加物等を用いて乳化または溶解する。
【００２０】
またブロックドポリイソシアネート化合物は、ポリイソシアネート化合物とブロック化剤との付加物であり、加熱によりブロック成分が遊離して活性なポリイソシアネート化合物を生ぜしめるものである。ポリイソシアネート化合物としては、例えばトリレンジイソシアネート、メタフェニレンジイソシアネート、ジフェニルメタンジイソシアネート、ヘキサメチレンジイソシアネート、ポリメチレンポリフェニルイソシアネート、トリフェニルメタントリイソシアネート等のポリイソシアネート、あるいはこれらポリイソシアネートと活性水素原子を２個以上有する化合物、例えばトリメチロールプロパン、ペンタエリスリトール、ポリアルキレングリコール等とをイソシアネート基（−ＮＣＯ）とヒドロキシル基（−ＯＨ）の比が１を越えるモル比で反応させて得られる末端イソシアネート基含有の多価アルコールアダクトポリイソシアネートなどが挙げられる。特にトリレジンイソシアネート、ジフェニルメタンジイソシアネート、ポリメチレンポリフェニルイソシアネートの如き芳香族ポリイソシアネートが優れた性能を発現するので好ましい。
【００２１】
ブロック化剤としては、例えばフェノール、チオフェノール、クレゾール、レゾルシノール等のフェノール類、ジフェニルアミン、キシリジン等の芳香族第２級アミン類、フタル酸イミド類、カプロラクタム、バレロラクタム等のラクタム類、アセトキシム、メチルエチルケトンオキシム、シクロヘキサンオキシム等のオキシム類および酸性亜硫酸ソーダなどがある。
【００２２】
第１処理剤は、上記ポリエポキシド化合物とブロクッドポリイソシアネート化合物及びポリブタジエンゴムラッテクスよりなり、その配合比は特に限定されないが、通常はポリエポキシド化合物１重量部に対してブロクッドポリイソシアネート化合物を２〜５重量部、ポリブタジエンゴムラッテクス（有効成分）を０．５〜２．０重量部配合し、処理剤中のエポキシ化合物の濃度は３％以下、好ましくは０．５〜２．０％とするのが、取扱い性の点で好ましい。
【００２３】
第１処理剤の付着量は、繊維重量に対し１〜８重量％、好ましくは３〜５重量％となるように処理を行う。
【００２４】
次に第２処理剤に用いるＲＦＬは、レゾルシンとフォルマリンとをアルカリまたは酸性触媒下で反応させて得られる初期縮合物（ＲＦ）とゴムラテックスの混合物であり、レゾルシン、フォルマリン、及びゴムラテックスの配合比率については公知技術のいずれを適用しても効果は見られる。通常は、レゾルシンとフォルマリンのモル比は１：０．１〜１：８、好ましくは１：０．５〜１：５である。またＲＦの使用量は、後述するクロロフェノール化合物の使用量によって変わるが、ＲＦとクロロフェノール化合物の合計量とゴムラッテクスとの固形分量比を、１：１〜１：１５、好ましくは１：３〜１：１２とすることが望ましい。なお、ここで用いられるゴムラテックスは、ニトリル・ブタジエンゴム（ＮＢＲ）ラテックスである。
【００２５】
上記ＲＦＬに配合されるクロロフェノール化合物は、パラクロルフェノール及びレゾルシンをホルムアルデヒドと共縮合した化合物であり、下記構造式（化５）で表される、３核体 （Ｉ）、５核体（ＩＩ）、７核体 （ＩＩＩ）を主成分とするものであるが、特に図１に示す分子量分布（共縮合生成物を蒸発乾固した固形分をテトラヒドロフランに溶解し、これを常法に従いＧＰＣ法にて測定）を有するものが好ましい。
【００２６】
【化５】

【００２７】
これら特殊クロロフェノール化合物と、レゾルシン・フォルマリンの配合比率は、被着ゴムの配合によっても微妙に変化するが、一般的には、前述のＲＦと特殊クロロフェノール化合物の配合割合を５０／５０〜８０／２０（重量比）とするのが好ましい。
【００２８】
本発明においては、第２処理剤には、さらに四フッ化エチレン樹脂（ＰＴＦＥ）微粒子の水分散体を、ＲＦＬとクロルフェノール化合物の全固形分に対し５〜２０重量％配合することが肝要である。この配合量が５重量％未満では、得られる処理コードの滑りを良くし、応力の一点集中を避けてかしめ性を改善する効果が不充分となる。一方、２０重量％を越える場合にはかしめ性は良好であるがゴムとの接着性が低下するので好ましくない。ＰＴＦＥ微粒子の粒径は、粒度分布としては０．１〜０．８μｍ、メジアン径は０．３μｍ程度が、均一に分散させるためには好ましい。
【００２９】
第２処理剤の付着量は、繊維重量に対し１〜６重量％、好ましくは２〜５重量％となるように処理を行う。
【００３０】
本発明においては、前記の撚糸したアラミド繊維を第一処理剤で処理した後１３０〜１８０℃で２〜５分間、好ましくは１〜３分間乾燥し、ついで１８０〜２６０℃、好ましくは２２０〜２５０℃の温度で０．５〜５．０分間、好ましくは１〜３分間熱処理し、次いで第二処理剤で処理後、１３０〜２５０℃で０．５〜５分間、好ましくは１〜３分間乾燥し、ついで１５０〜２６０℃、好ましくは２２０〜２５０℃の温度で０．５〜５．０分間、好ましくは１〜３分間熱処理する。熱処理温度が低すぎるとゴム類との接着が不十分となりやすく、一方温度が高すぎると接着剤自身の硬化が起こり、繊維を硬くしたり、強力劣化を起こしたりして実用に供し難くなる。
【００３１】
得られたアラミド繊維コードは、公知の技術、例えば、チューブゴムよりなる内層の上にブレーダーにより所定密度になるよう、得られたアラミド繊維コードを所定の角度を付けて配設する。次いで、この上に層間ゴムシートを配した後再度繊維コードをブレーダーにより配設し、これを所定回数行う。最後に外側補強繊維を保護するためのカバーゴムからなる外層を配設した後、これを例えば蒸気加硫釜中で蒸気加硫してゴムホースとなす。なお、前記繊維コードの配設は共にスパイラル構造にしてもよい。
【００３２】
ここで内層、層間、及び外層のゴムとしては、従来と同様に、内層はＮＢＲ、ＣＲ、水素化ＮＢＲ（ＨＮＢＲ）、ＣＳＭ等が用いられ、層間はＮＢＲ等が使用され、外層はＣＲ、ＣＳＭ等が使用される。
【００３３】
【発明の作用効果】
本発明では、アラミド繊維からなるヤーンに先ず予備撚りを施した後に、これを複数本合糸して再度同一方向へ撚りをかけているので、単繊維の引き揃え性が向上してかしめ時の応力集中を防ぐことができる。また第２処理剤中にはＰＴＦＥ微粒子が配合されているので、得られた処理コードから形成されるブレードもしくはスパイラル構造を有するホースは、金具を取り付ける際、このＰＴＦＥ微粒子の働きによりコードが微妙に滑り、かしめ時の応力集中を防ぐことができる。これらの結果、金具内でのかしめ破断を抑制する効果が向上するものと推定される。また、先ず第１処理剤により、アラミド繊維表面がエポキシ化合物により活性化され、次いで第２処理剤によりゴムとの接着性が発現されているので、ＮＢＲ、ＣＲ、ＣＳＭなどとも優れた接着性能を示し、極めて良好なゴムホースが得られる。
【００３４】
【実施例】
以下、実施例により本発明を具体的に説明する。なお、実施例における特性の評価は下記の方法に従った。
【００３５】
＜剥離接着力＞
ホースを長さ１インチに切断し、その外側ゴムを、ホースの周長に沿って剥離したときの強力を表す。
【００３６】
＜金具かしめ性＞
実際にホースの先端に口金を取りつけ、その部分を八方締めかしめ方式により、ホース肉厚の圧縮比（締め率５０％は、ホース肉厚の５０％圧縮）により締めつけた後、ホースを分解し、かしめ部でのコード切断の有無を調査し、かしめ性の評価とした。
【００３７】
＜捩じり取り付けインパルス性能試験＞
ホースの捩じり角度１５°及び３０°の状態で、温度１２０℃、圧力１８０ｋｇｆ／ｃｍ^２ の条件で台形波インパルスをかけ、ホース破壊の起こる回数で示した。最高１００万回までとして評価した。評価に用いたゴムの配合組成は以下の通りである。
【００３８】
ＥＰＤＭ １００部
ＨＡＦ−カーボンブラック １２０部
プロセスオイル（パラフィン系） ９０部
亜鉛華 ５部
ステアリン酸 ３部
加硫剤 ３．５部
加硫促進剤 ２．５部
【００３９】
［実施例１〜６、比較例１〜７］
アラミド繊維として、コ・パラフェニレン・３・４’オキシジフェニレン・テレフタラミドからなる１５００デニール、１０００フィラメント（商品名：テクノーラ；帝人株式会社製）のヤーンに先ず４Ｔ／１０ｃｍの撚りをかけた。ついでこのヤーンを２本合わせ、同一方向へ更に６Ｔ／１０ｃｍの撚りをかけて３０００デニールのコードとした。このコードを、第１処理剤として、ポリエポキシド化合物（商品名：デナコールＥＸ６１１；ナガセ化成株式会社製、ソルビトールグリシジルエーテル）とブロックドポリイソシアネート化合物（商品名：ＤＭ６０１１；明成化学工業株式会社製）とポリブタジエンゴムラテックス（商品名：ニッポールＬＸ１１１ＮＦ；日本ゼオン株式会社製）を有効成分量比率で１０：３８：１に混合したものを、５％水分散液に調整した処理液に浸漬し、たるまない程度のテンションをかけ１２０度で２分間乾燥させ、次いで１５０度で１分間の熱処理を行った。
【００４０】
次いで、第２処理剤として、先ずレゾルシン１７部とホルマリンの３７％水溶液１４．９部と苛性ソーダの１０％水溶液１３．３部を１０８．９部の水中で反応させてＲＦレジンを得た。次に、このレジンにアクリロニトリル・ブタジエンゴムラテックス（商品名：ニッポールＬＸ１５６２；日本ゼオン株式会社製、固形分４０％）２８１．７部を加え、ついで水３７２．５部を加え２４時間、２０℃で熟成した。その後、ＲＦレジンに対し，固形分比で４倍のクロロフェノール化合物（商品名：デナボンド；ナガセ化成株式会社製、固形分；２０％）を添加し、充分攪拌しながら６時間熟成する。使用時に平滑成分として、四フッ化ポリエチレン微粒子の水分散液（商品名：Ｄ−１；ダイキン工業株式会社製、濃度６０％）を６０部添加し、よく攪拌し、加工処理剤として使用する。処理剤の粘度，付着量のコントロールは，該処理剤への水の添加希釈により調節する。
【００４１】
この第２処理剤中へ浸漬処理を行った後，１３０〜１６０℃で１〜３分間乾燥後、１８０〜２３５℃で１〜２分間の熱処理を行った。得られた接着処理アラミドコードを、交差角１０８度で内管ゴムにブレードし、層間ゴムを巻き、更にコードをブレードし、その上に外管ゴムを配置した。得られたホースを、１５０℃の蒸気加硫釜中で６０分間蒸気加硫を行い、ホースを得た。表１に、その結果を示す。本発明のコードは、金具かしめによるコード破断もなく、また接着性も保持し、ホースインパルステストでも破壊が見られず、高性能である。
【００４２】
【表１】

【００４３】
【表２】

【図面の簡単な説明】
【図１】本発明で用いられるクロロフェノール化合物の好ましい分子量分布の１例である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite of fiber and rubber, and more particularly to an aramid fiber cord for reinforcing a hose such as a high pressure hose excellent in adhesiveness between an aramid fiber and rubber, and a rubber hose using the same.
[0002]
More specifically, the present invention relates to a hose that can reduce or maintain fatigue of a reinforcing yarn due to a tightening rate when a hose fitting is attached and can improve impulse performance by being attached in a twisted state.
[0003]
[Prior art]
Conventionally, polyester fiber, nylon fiber, rayon fiber, etc. have been used for the reinforcement layer of these fiber reinforced hoses, but the environment and conditions of use of the hose itself have become more severe, higher strength and higher heat resistance. Reinforcing fibers with a certain length have been demanded. Therefore, aramid fibers have excellent properties such as high strength, high Young's modulus, and low shrinkage, and fiber reinforced high-pressure rubber hoses that have aramid fibers in the reinforcing layer have been used.
[0004]
A fiber-reinforced high-pressure rubber hose having a reinforcing layer made of aramid fibers has, for example, a reinforcing layer made of aramid fibers disposed on an inner rubber layer disposed in the innermost layer, and a reinforcing thread of the reinforcing layer on the inner layer. An interlayer rubber layer for improving adhesion is disposed, and a reinforcing layer similar to the above and an outer rubber layer for protecting the reinforcing layer are disposed on the interlayer rubber layer.
[0005]
The inner rubber layer is made of acrylonitrile butadiene (NBR), polychloroprene (CR), etc., the interlayer rubber is made of NBR, etc., and the outer rubber layer is made of CR, chlorosulfonated polyethylene rubber (CSM), etc. Yes.
[0006]
The aramid fiber used for the reinforcing layer is polyparaphenylene terephthalamide or copolyparaphenylene 3,4′oxydiphenylene terephthalamide, and these fibers form a blade structure or a spiral structure to form a reinforcing layer. (JP-A-6-15779).
[0007]
However, in the above-described fiber reinforced high-pressure rubber hose, the high temperature impact resistance performance is remarkably lowered as the hose twist angle increases, and the hose is damaged when used for a long time in a high temperature state or a twisted state. There was a problem.
[0008]
OBJECT OF THE INVENTION
The present invention has been made against the background described above. It is an object of the present invention to be used for a reinforcing fiber of a rubber hose particularly used for a flow path of a pressure fluid, when the cord itself has a tightened form and the reinforcing fiber layer is caulked for attaching a hose fitting. Another object of the present invention is to provide an aramid fiber cord for reinforcing a hose and a rubber hose using the same, in which the stress is not well dispersed to cause breakage of the cord and the adhesiveness to the rubber matrix is improved.
[0009]
[Structure of the invention]
According to a first aspect of the present invention, "(Claim 1) is an aramid fiber cord for reinforcing a hose of a fiber reinforced rubber hose having a reinforcing layer between an inner rubber layer and an outer rubber layer. After pre-twisting, aramid fibers twisted in the same direction as pre-twisting are coated with a first treatment agent comprising a polyepoxide compound, a blocked polyisocyanate compound and a polybutadiene rubber latex, and then resorcin-formalin A trinuclear (I), 5-nuclear compound (III) represented by the following formula (Chemical Formula 3), which is a compound obtained by cocondensing parachlorophenol and resorcin with formaldehyde to nitrile butadiene rubber latex (RFL) II) and a chlorophenol compound containing 7-nuclear body (III) as a main component, and tetrafluoropolyethylene as a smoothing component. An aramid fiber cord for reinforcing a hose, which is coated with a second treatment agent containing 5 to 20% by weight of an aqueous dispersion of fine particles based on the total solid content of RFL and chlorophenol compound. And
[0010]
[Chemical 3]

[0011]
Further, the second invention is “(Claim 2) In a fiber reinforced rubber hose having a reinforcing layer made of an aramid fiber cord between the inner rubber layer and the outer rubber layer, after the aramid fiber cord is pre-twisted , Aramid fibers twisted in the same direction as the pre-twist are coated with a first treatment agent comprising a polyepoxide compound, a blocked polyisocyanate compound and a polybutadiene rubber latex, and then resorcin / formalin / nitrile / butadiene rubber latex (RFL). In addition, a compound obtained by co-condensation of parachlorophenol and resorcin with formaldehyde and represented by the following formula (Formula 4): a trinuclear (I), a five-nuclear (II), and a seven-nuclear (III ) With a chlorophenol compound as a main component and an aqueous dispersion of tetrafluoropolyethylene fine particles as a smoothing component , Fiber-reinforced rubber hose, wherein the second treatment agent was blended 5 to 20 wt% based on the solids content of the sum of RFL and chlorophenol compound is aramid fiber cord coated. "A.
[0012]
[Formula 4]

[0013]
The aramid fiber referred to in the present invention is a polyamide composed of an aromatic dicarboxylic acid and an aromatic diamine, or an aromatic aminocarboxylic acid, and a fiber composed of a copolymerized polyamide thereof, but particularly excellent in strength and elastic modulus. Because of its high hose reinforcement effect, poly-p-phenylene terephthalamide fiber, copoly-p-phenylene- (3,4′-oxydiphenyl) terephthalamide fiber (for example, Teijin Limited: Technora), etc. These para-oriented aramid fibers are preferred.
[0014]
There is no need to specifically limit the single fiber fineness of the aramid fiber, but if it is too small, production troubles are likely to occur, and the reinforcing effect tends to be insufficient. On the other hand, since aramid fibers are generally wet-spun, it is difficult to stably produce fibers having a large fineness. Therefore, usually 0.5 to 5 denier, preferably 1 to 3 denier is used. The total fineness of the aramid fiber bundle is about 500 to 2000 denier, and outside this range, the effect of pre-twisting described later tends to be small.
[0015]
In the present invention, it is necessary that the aramid fiber is first pre-twisted, and then a plurality of, preferably two, fiber bundles subjected to the pre-twist are combined and further twisted. Here, the direction of twisting should be the same as that of pre-twisting. When the reinforcing fiber layer is caulked to attach the hose fitting, the stress is well dispersed to make cord breakage less likely to occur (hereinafter simply caulking). It may be called good nature) .
[0016]
The number of pre-twisting is preferably 2 to 5 times per 10 cm, particularly about 4 times, and if it is less than 2 times, the alignment of the single fibers is reduced and the caulking property is lowered. There is a tendency for strength to decrease.
[0017]
On the other hand, the number of twists of the twisted yarn after the combined yarn is 3 to 15 times per 10 cm, preferably 5 to 10 times.
[0018]
Next, the polyepoxide compound used for the first treating agent is a compound containing 0.2 g equivalent or more per 100 g of the compound in one molecule. Reaction products of polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, polyethylene glycol and halogen-containing epoxides such as epichlorohydrin, resorcin / bis (4-hydroxyphenyl) dimethylmethane, phenol / formaldehyde resin, resorcin A reaction product of a polyhydric phenol such as formaldehyde resin and the halogen-containing epoxide, a polyepoxide compound obtained by oxidizing an unsaturated compound with peracetic acid or hydrogen peroxide, etc. , 4-epoxycyclohexene epoxide, 3,4-epoxycyclohexene methyl-3,4-epoxycyclohexene carboxylate, bis (3,4-epoxy-6methyl-cyclohexylmethyl) adipate Etc. can be mentioned. Among these, a reaction product of a polyhydric alcohol and epichlorohydrin, that is, a polyglycidyl ether compound of a polyhydric alcohol is preferable because it exhibits excellent performance.
[0019]
Such polyepoxide compounds are usually used as emulsions. In order to obtain an emulsified solution or solution, for example, such a polyepoxide compound as it is or dissolved in a small amount of a solvent is used as a known emulsifier, for example, sodium alkylbenzenesulfonate, dioctylsulfosuccinate sodium salt, nonylphenolethylene. Emulsified or dissolved using an oxide adduct or the like.
[0020]
The blocked polyisocyanate compound is an adduct of a polyisocyanate compound and a blocking agent, and releases a block component by heating to produce an active polyisocyanate compound. Examples of the polyisocyanate compound include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, or two or more of these polyisocyanates and active hydrogen atoms. For example, trimethylolpropane, pentaerythritol, polyalkylene glycol, and the like having a terminal isocyanate group-containing compound obtained by reacting an isocyanate group (—NCO) and a hydroxyl group (—OH) in a molar ratio exceeding 1. And monohydric alcohol adduct polyisocyanate. In particular, aromatic polyisocyanates such as triresin isocyanate, diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate exhibit preferable performance.
[0021]
Examples of the blocking agent include phenols such as phenol, thiophenol, cresol and resorcinol, aromatic secondary amines such as diphenylamine and xylidine, lactams such as phthalimides, caprolactam and valerolactam, acetoxime and methyl ethyl ketone. Examples include oximes such as oxime and cyclohexane oxime, and acidic sodium sulfite.
[0022]
The first treating agent is composed of the polyepoxide compound, the broccid polyisocyanate compound and the polybutadiene rubber latex, and the blending ratio thereof is not particularly limited, but usually 2 to 5 of the block polyisocyanate compound is added to 1 part by weight of the polyepoxide compound. Part by weight, 0.5 to 2.0 parts by weight of polybutadiene rubber latex (active ingredient) is blended, and the concentration of the epoxy compound in the treatment agent is 3% or less, preferably 0.5 to 2.0%. From the viewpoint of handleability, it is preferable.
[0023]
The amount of the first treatment agent attached is 1 to 8% by weight, preferably 3 to 5% by weight, based on the fiber weight.
[0024]
Next, RFL used for the second treating agent is a mixture of an initial condensate (RF) obtained by reacting resorcin and formalin in the presence of an alkali or acidic catalyst, and rubber latex. Resorcin, formalin, and rubber latex As for the blending ratio, any of known techniques can be applied. Usually, the molar ratio of resorcin to formalin is 1: 0.1 to 1: 8, preferably 1: 0.5 to 1: 5. The amount of RF used varies depending on the amount of chlorophenol compound to be described later, but the solid content ratio of the total amount of RF and chlorophenol compound to rubber latex is 1: 1 to 1:15, preferably 1: 3. It is desirable to set it to ˜1: 12. The rubber latex used here is nitrile butadiene rubber (NBR) latex.
[0025]
The chlorophenol compound blended in the RFL is a compound obtained by co-condensing parachlorophenol and resorcin with formaldehyde, and is represented by the following structural formula (Chemical Formula 5). ), 7-nuclear body (III) as a main component, especially the molecular weight distribution shown in FIG. 1 (the solid content obtained by evaporating and drying the cocondensation product is dissolved in tetrahydrofuran, and this is dissolved in a GPC method according to a conventional method. Those having (measured in) are preferred.
[0026]
[Chemical formula 5]

[0027]
Although the blending ratio of these special chlorophenol compounds and resorcin / formalin slightly changes depending on the blending of the rubber to be adhered, generally, the blending ratio of the aforementioned RF and the special chlorophenol compound is 50/50 to The ratio is preferably 80/20 (weight ratio).
[0028]
In the present invention, it is important that the second treatment agent further contains an aqueous dispersion of tetrafluoroethylene resin (PTFE) fine particles in an amount of 5 to 20% by weight based on the total solid content of RFL and the chlorophenol compound. is there. When the blending amount is less than 5% by weight, the effect of improving the caulking property by improving the slippage of the obtained treatment cord and avoiding the concentration of one point of stress becomes insufficient. On the other hand, if it exceeds 20% by weight, the caulking property is good, but the adhesion to rubber is lowered, which is not preferable. The particle diameter of the PTFE fine particles is preferably about 0.1 to 0.8 μm as the particle size distribution and about 0.3 μm as the median diameter for uniform dispersion.
[0029]
The amount of the second treatment agent is 1 to 6% by weight, preferably 2 to 5% by weight, based on the fiber weight.
[0030]
In the present invention, the twisted aramid fiber is treated with the first treatment agent and then dried at 130 to 180 ° C. for 2 to 5 minutes, preferably 1 to 3 minutes, and then 180 to 260 ° C., preferably 220 to 250. Heat treatment at a temperature of 0.degree. C. for 0.5 to 5.0 minutes, preferably 1 to 3 minutes, and then treatment with the second treating agent, followed by drying at 130 to 250.degree. Then, heat treatment is performed at a temperature of 150 to 260 ° C., preferably 220 to 250 ° C. for 0.5 to 5.0 minutes, preferably 1 to 3 minutes. If the heat treatment temperature is too low, the adhesion to the rubber tends to be insufficient, while if the temperature is too high, the adhesive itself is cured, making the fiber hard or causing strong deterioration, making it difficult to put it into practical use.
[0031]
The obtained aramid fiber cord is disposed at a predetermined angle so that the aramid fiber cord has a predetermined density by a braider on a known technique, for example, an inner layer made of tube rubber. Next, after an interlayer rubber sheet is disposed thereon, the fiber cord is again disposed by a blader, and this is performed a predetermined number of times. Finally, after an outer layer made of a cover rubber for protecting the outer reinforcing fiber is disposed, this is steam vulcanized in, for example, a steam vulcanizer to form a rubber hose. The fiber cords may be arranged in a spiral structure.
[0032]
Here, as the rubber of the inner layer, the interlayer, and the outer layer, NBR, CR, hydrogenated NBR (HNBR), CSM, etc. are used for the inner layer, and NBR, etc. are used for the inner layer, and CR, CSM are used for the outer layer. Etc. are used.
[0033]
[Effects of the invention]
In the present invention, after first pre-twisting a yarn made of aramid fibers, a plurality of these yarns are combined and twisted in the same direction again. Stress concentration can be prevented. In addition, since the PTFE fine particles are blended in the second treatment agent, the hose having a blade or spiral structure formed from the obtained treatment cord has a subtle cord due to the action of the PTFE fine particles when attaching the metal fitting. Stress concentration during slipping and caulking can be prevented. As a result, it is presumed that the effect of suppressing caulking fracture in the metal fitting is improved. Moreover, since the aramid fiber surface is first activated by the epoxy compound by the first treatment agent and then the adhesiveness to the rubber is expressed by the second treatment agent, it has excellent adhesion performance with NBR, CR, CSM, etc. A very good rubber hose is obtained.
[0034]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. In addition, evaluation of the characteristic in an Example followed the following method.
[0035]
<Peel adhesion>
It represents the strength when the hose is cut to 1 inch in length and the outer rubber is peeled along the circumference of the hose.
[0036]
<Fitting caulking>
After actually attaching the base to the tip of the hose and tightening that part with the compression ratio of the hose wall thickness (clamping rate 50% is 50% compression of the hose wall thickness), the hose is disassembled. The caulking part was examined for the presence of cord breakage, and the caulking property was evaluated.
[0037]
<Torsion mounting impulse performance test>
A trapezoidal wave impulse was applied under conditions of a temperature of 120 ° C. and a pressure of 180 kgf / cm ^{2 with} the hose twisting angles being 15 ° and 30 °, and the number of times the hose was broken was shown. It was evaluated as up to 1 million times. The compounding composition of the rubber used for the evaluation is as follows.
[0038]
EPDM 100 parts HAF-carbon black 120 parts process oil (paraffinic) 90 parts zinc white 5 parts stearic acid 3 parts vulcanizing agent 3.5 parts vulcanization accelerator 2.5 parts
[Examples 1-6, Comparative Examples 1-7]
As an aramid fiber, a yarn of 1500 denier and 1000 filaments (trade name: Technora; manufactured by Teijin Ltd.) made of co-paraphenylene, 3.4′oxydiphenylene, and terephthalamide was first twisted at 4T / 10 cm. The two yarns were then combined and twisted 6T / 10 cm in the same direction to form a 3000 denier cord. This code is used as a first treatment agent as a polyepoxide compound (trade name: Denacol EX611; manufactured by Nagase Kasei Co., Ltd., sorbitol glycidyl ether) and a blocked polyisocyanate compound (trade name: DM6011; manufactured by Meisei Chemical Industry Co., Ltd.) and polybutadiene. A rubber latex (trade name: Nippon LX111NF; manufactured by Nippon Zeon Co., Ltd.) mixed in an active ingredient amount ratio of 10: 38: 1 is immersed in a treatment liquid adjusted to a 5% aqueous dispersion, and is not sluggish. Tension was applied and dried at 120 degrees for 2 minutes, and then heat treatment was performed at 150 degrees for 1 minute.
[0040]
Next, as a second treating agent, 17 parts of resorcin, 14.9 parts of a 37% aqueous solution of formalin, and 13.3 parts of a 10% aqueous solution of caustic soda were reacted in 108.9 parts of water to obtain an RF resin. Next, 281.7 parts of acrylonitrile butadiene rubber latex (trade name: Nippon LX1562, manufactured by Nippon Zeon Co., Ltd., 40% solid content) was added to this resin, and then 372.5 parts of water was added and the mixture was added at 20 ° C. for 24 hours. Aged. Thereafter, a chlorophenol compound (trade name: Denabond; manufactured by Nagase Kasei Co., Ltd., solid content: 20%) having a solid content ratio of 4 times is added to the RF resin, and aged for 6 hours with sufficient stirring. As a smooth component at the time of use, 60 parts of an aqueous dispersion of tetrafluoropolyethylene fine particles (trade name: D-1; manufactured by Daikin Industries, Ltd., concentration 60%) is added, stirred well, and used as a processing agent. The viscosity and adhesion amount of the treatment agent are controlled by adding and diluting water to the treatment agent.
[0041]
After the immersion treatment in the second treating agent, the film was dried at 130 to 160 ° C. for 1 to 3 minutes and then heat treated at 180 to 235 ° C. for 1 to 2 minutes. The obtained adhesion-treated aramid cord was braided on the inner tube rubber at an intersection angle of 108 degrees, wound with an interlayer rubber, further braided with the cord, and the outer tube rubber was disposed thereon. The obtained hose was steam vulcanized in a steam vulcanizer at 150 ° C. for 60 minutes to obtain a hose. Table 1 shows the results. The cord of the present invention has no cord breakage due to the caulking of metal fittings, maintains adhesiveness, does not show breakage even in a hose impulse test, and has high performance.
[0042]
[Table 1]

[0043]
[Table 2]

[Brief description of the drawings]
FIG. 1 is an example of a preferred molecular weight distribution of a chlorophenol compound used in the present invention.

Claims (2)

In the aramid fiber cord for reinforcing a hose of a fiber reinforced rubber hose having a reinforcing layer between an inner rubber layer and an outer rubber layer, the fiber cord is pre-twisted and then in the same direction as the pre-twist the twisting aramid fibers subjected to, polyepoxide compounds, the first treatment agent is coated comprising a blocked polyisocyanate compound and a polybutadiene rubber latex, then the resorcinol formalin-nitrile-butadiene rubber latex (RFL), para-chlorophenol And resorcin co-condensed with formaldehyde, which is represented by the following formula (Chemical Formula 1): a trinuclear body (I), a 5-nuclear body (II), and a 7-nuclear body (III). Chlorophenol compound to be blended, and an aqueous dispersion of tetrafluoropolyethylene fine particles as a smoothing component, RFL and B phenolic compounds hose reinforcing aramid fiber cord second treating agent was blended 5 to 20 wt% based on the solids content of the total, characterized in that formed by coating.

In a fiber reinforced rubber hose having a reinforcing layer made of an aramid fiber cord between an inner rubber layer and an outer rubber layer, the aramid fiber in which the aramid fiber cord is pre-twisted and then twisted in the same direction as the pre-twist The first treatment agent comprising a polyepoxide compound, a blocked polyisocyanate compound and a polybutadiene rubber latex is coated, and then, resorcin / formalin / nitrile / butadiene rubber latex (RFL) is mixed with parachlorophenol and resorcin with formaldehyde. A co-condensed compound containing a chlorophenol compound represented by the following formula (Chemical Formula 2), which is mainly composed of a trinuclear body (I), a pentanuclear body (II), and a 7-nuclear body (III). In addition, an aqueous dispersion of tetrafluoropolyethylene fine particles as a smoothing component, RFL and chlorophenolation Fiber reinforced rubber hose, wherein the second treatment agent was blended 5 to 20 wt% total of the solid content of the object is an aramid fiber cord coated.

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