JP2008106085A - Wet friction material and method for producing the same - Google Patents
Wet friction material and method for producing the same Download PDFInfo
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- 238000009832 plasma treatment Methods 0.000 claims abstract description 42
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- 229920002972 Acrylic fiber Polymers 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229920001342 Bakelite® Polymers 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
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- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
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- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
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- 230000008859 change Effects 0.000 description 1
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- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
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- 238000000227 grinding Methods 0.000 description 1
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- 229910052734 helium Inorganic materials 0.000 description 1
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- 238000007731 hot pressing Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
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- -1 isocyanate compound Chemical class 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
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- 229910052754 neon Inorganic materials 0.000 description 1
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- SNICXCGAKADSCV-UHFFFAOYSA-N nicotine Chemical compound CN1CCCC1C1=CC=CN=C1 SNICXCGAKADSCV-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
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- 229920003987 resole Polymers 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
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- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
本発明は、自動車等の自動変速機における動力伝達系のクラッチフェーシングなどに使用される、耐熱性や層間剪断特性に優れた湿式摩擦材に関する。 The present invention relates to a wet friction material having excellent heat resistance and interlaminar shear characteristics, which is used for clutch facing of a power transmission system in an automatic transmission such as an automobile.
一般に湿式摩擦材は、例えば特公昭５８−４７３４５号公報や特開平１１−２０１２０６号公報などに開示されているように、アラミド繊維やセルロース繊維などの繊維材料と、摩擦調整剤や固体潤滑剤等の各種無機フィラーを湿式抄造して紙状の基材を得、これにフェノール樹脂等の結合剤樹脂を含浸して加圧・硬化して製造される。 In general, wet friction materials include fiber materials such as aramid fibers and cellulose fibers, friction modifiers, solid lubricants and the like as disclosed in, for example, Japanese Patent Publication No. 58-47345 and Japanese Patent Application Laid-Open No. 11-201206. The above-mentioned various inorganic fillers are wet-made to obtain a paper-like base material, which is impregnated with a binder resin such as a phenol resin, and pressed and cured.
繊維材料としては、従来木材パルプやリンターパルプ等のセルロース繊維が多く用いられているが、昨今の自動車エンジンの出力増大や変速機の小型化等により、動力を伝達するために使用される湿式摩擦材への耐熱性や層間剪断強度などの機械的特性に関する要求が厳しくなっているため、耐熱性に劣るセルロース繊維を湿式摩擦材を用いることは困難となってきており、耐熱性に優れたパラ型アラミド繊維パルプ等を主として用いるようになってきた。 Cellulose fibers such as wood pulp and linter pulp have been used as fiber materials. However, wet friction is used to transmit power due to increased output of automobile engines and downsizing of transmissions in recent years. The demands on mechanical properties such as heat resistance and interlaminar shear strength of materials have become stricter, making it difficult to use wet friction materials for cellulose fibers that are inferior in heat resistance. Type aramid fiber pulp has been mainly used.
しかしながら、パラ型アラミド繊維に代表される有機繊維パルプは、表面が化学的に不活性であるが故に、セルロース繊維等に比べフェノール樹脂等の結合剤樹脂との接着力が低い問題がある。そのため湿式摩擦材に用いた場合、剪断特性等の機械的物性や高耐久性の要求に対し、十分に対応できないのが現状であり、セルロースを接着性向上のため混合使用することが行われてきた。 However, organic fiber pulp typified by para-type aramid fibers has a problem that its surface has a chemically inert surface and therefore has a lower adhesive force with a binder resin such as a phenol resin than cellulose fibers. For this reason, when used in wet friction materials, it is currently impossible to fully meet the demands for mechanical properties such as shearing properties and high durability, and cellulose has been mixed and used to improve adhesion. It was.
そこで、パラ型アラミド繊維に代表される有機繊維パルプの結合剤樹脂との接着性を向上させる方法が検討され、例えば特開２００２−１９４６６９号公報などでは、アラミド繊維をフィルムフォーマー、シランカップリング剤および界面活性剤で処理する方法が報告されている。この方法では、結晶サイズがある一定よりも小さく、紡出後の水分率をある一定以上に維持したアラミド繊維に対してフィルムフォーマー、シランカップリング剤および界面活性剤で処理することにより、繊維表面だけではなく繊維内部にまで剤が浸透し、マトリックス樹脂との接着性を付与することができるが、この方法では結晶サイズや水分率に明確な制約があるため、有機繊維パルプのような既製品に適用することは困難である。 Therefore, a method for improving the adhesiveness of organic fiber pulp with a binder resin typified by para-type aramid fibers has been studied. For example, in Japanese Patent Application Laid-Open No. 2002-194669, aramid fibers are used as film formers and silane couplings. Methods of treatment with agents and surfactants have been reported. In this method, aramid fibers whose crystal size is smaller than a certain value and whose moisture content after spinning is maintained above a certain value are treated with a film former, a silane coupling agent, and a surfactant to obtain fibers. Although the agent can penetrate not only to the surface but also to the inside of the fiber and impart adhesion to the matrix resin, this method has clear restrictions on the crystal size and moisture content, so existing methods such as organic fiber pulp. It is difficult to apply to products.
また特開２００５−１９４６４８号公報では、繊維構造物の表面をバクテリアルセルロースで被覆することによりマトリックス樹脂との接着性を向上させる方法が報告されている。この方法では、通常のセルロース繊維よりも微細で比表面積が大きいバクテリアセルロースで処理するために、少量の被覆によっても効率的に樹脂接着性を向上させることができるものの、依然として耐熱性に劣るセルロース繊維を含むことになり、２００〜３００℃の高温で使用した場合、バクテリアルセルロースの分解が起こるため、その分解により剪断特性などの機械的特性が大幅に低下することが懸念される。 Japanese Patent Application Laid-Open No. 2005-194648 reports a method for improving the adhesion to a matrix resin by coating the surface of a fiber structure with bacterial cellulose. In this method, since the cellulose cellulose is treated with bacterial cellulose that is finer and has a larger specific surface area than ordinary cellulose fibers, the resin adhesion can be improved efficiently even with a small amount of coating, but the cellulose fibers still have poor heat resistance. When it is used at a high temperature of 200 to 300 ° C., the degradation of bacterial cellulose occurs, and there is a concern that the mechanical properties such as shearing properties are significantly lowered by the decomposition.
更に、不活性なパラ型アラミド繊維などの有機繊維を化学的に修飾する手法として、例えば特開２００４−３６０１１３号公報などでは、イソシアネート化合物ガス雰囲気下でプラズマ処理を行い、アラミド繊維の表面を改質しゴムとの接着性を向上させる方法が報告されている。しかしこのような処理では、繊維表面の活性が経時的に変化するために、例えば高度にフィブリル化したパルプを得るためには、更にいくつもの工程を通過させる必要があり十分な効果が得られない可能性がある。またここではゴムとの接着性を向上させるための接着処理液であるレゾルシン−ホルマリン−ゴムラテックス（ＲＦＬ）との化学結合に主眼を置いており、フェノール樹脂のような結合剤樹脂との接着性を挙げるための検討が十分になされていない。 Further, as a method for chemically modifying organic fibers such as inert para-aramid fibers, for example, in Japanese Patent Application Laid-Open No. 2004-360113, plasma treatment is performed in an isocyanate compound gas atmosphere to modify the surface of aramid fibers. There has been reported a method for improving the adhesion to rubber. However, in such a treatment, since the activity of the fiber surface changes with time, for example, in order to obtain a highly fibrillated pulp, it is necessary to pass through a number of steps and a sufficient effect cannot be obtained. there is a possibility. Here, the main focus is on chemical bonding with resorcin-formalin-rubber latex (RFL), which is an adhesion treatment liquid for improving the adhesion with rubber, and adhesion with a binder resin such as a phenol resin. There is not enough consideration to list.
同様に特開２００３−３１３７７０号公報では、アラミド繊維及び／またはアラミドフィブリッド繊維を含むアラミド基材に対して、グラフト処理や放電処理により電解液などの保持性を高める方法が報告されている。しかし、この方法においてはアラミド基材に対する電解液の保持性にのみ着目しており、結合剤樹脂との接着向上や最適な放電処理条件などについては十分検討されているものではない。
こうした現状に鑑み、アラミド繊維と結合剤樹脂との接着性を高めた、又セルロース等を使用しない高温耐久性に優れ、且つ機械的特性に優れた湿式摩擦材の開発が大いに望まれていた。
Similarly, Japanese Patent Application Laid-Open No. 2003-313770 reports a method for increasing the retention of an electrolytic solution or the like by grafting or discharge treatment on an aramid base material including an aramid fiber and / or an aramid fibrid fiber. However, this method focuses only on the retention of the electrolytic solution with respect to the aramid base material, and has not been sufficiently studied for improvement in adhesion to the binder resin, optimal discharge treatment conditions, and the like.
In view of these circumstances, there has been a great demand for the development of a wet friction material that has improved adhesion between aramid fibers and a binder resin, is excellent in high-temperature durability without using cellulose or the like, and is excellent in mechanical properties.
セルロース等を使用せずとも耐熱性に優れ、且つ層間剪断特性等の機械的特性の高温耐久性に優れた湿式摩擦材を提供することを目的とする。 An object of the present invention is to provide a wet friction material that is excellent in heat resistance without using cellulose or the like and excellent in high-temperature durability such as mechanical properties such as interlayer shearing properties.
本発明者は、本課題達成のため鋭意検討を重ねた結果、繊維材料、無機フィラー、摩擦調整剤等の成分から成る湿式摩擦材において、繊維材料として、高度にフィブリル化したアラミドパルプをある特定の条件範囲でプラズマ処理したものを使用することにより、層間剪断特性などの機械的特性に優れた湿式摩擦材が得られ、更に耐熱性が低いセルロースパルプなどを含まないために、耐熱性にも優れた湿式摩擦材が得られることを見出し本発明に到達した。 As a result of intensive studies to achieve this task, the present inventor has identified highly fibrillated aramid pulp as a fiber material in a wet friction material composed of components such as a fiber material, an inorganic filler, and a friction modifier. By using a material that has been plasma-treated in the above range of conditions, a wet friction material having excellent mechanical properties such as interlaminar shearing properties can be obtained, and since it does not contain cellulose pulp with low heat resistance, it also has good heat resistance. The present inventors have found that an excellent wet friction material can be obtained and have reached the present invention.
本発明により、プラズマ処理により、アラミド繊維表面の接着力が増大することにより、湿式摩擦材の機械的物性、特に引張強度、引張せん断力を大幅に向上させることが出来る。セルロース等の接着力アップ成分を使用せずとも、クラッチなどに使用される湿式摩擦材の耐熱性や層間剪断特性等の機械的特性を向上させることができ、自動車等の自動変速機における動力伝達系のクラッチフェーシングなどに有用に使用される。 According to the present invention, the mechanical properties of the wet friction material, in particular, the tensile strength and the tensile shear force can be greatly improved by increasing the adhesive strength of the aramid fiber surface by plasma treatment. Even without using an adhesive strength-enhancing component such as cellulose, the mechanical properties such as heat resistance and interlaminar shear properties of wet friction materials used in clutches can be improved. It is useful for system clutch facings.
本発明における繊維状材料としては、パラ型全芳香族ポリアミド繊維やその共重合体、芳香族ポリエステル繊維、ポリベンザゾール繊維、メタ型アラミド繊維やその共重合体、アクリル繊維、ポリイミド繊維、ポリアミド繊維などの有機合成繊維を高度にフィブリル化したパルプ状繊維があげられるが、中でもパラ型全芳香族ポリアミド繊維の高度にフィブリル化したアラミドパルプ（以後パラ型全芳香族ポリアミド繊維の高度にフィブリル化したアラミドパルプを単にアラミドパルプと略称する）が最も好ましい。これらの繊維状材料は単一または複数種組み合わせて用いることができ、その種類や形態、組合せ、配合比率等は特に限定されるものではないが、耐熱性や抄紙性などを考慮すると、アラミドパルプを含むことが好ましい。又効果を阻害しない範囲で請求範囲外の低フィブリル化アラミドパルプ、フィブリルの無い短繊維を混合使用することが出来る。繊維状材料の配合量としては、１０〜７０重量％、好ましくは１５〜６０重量％、さらに好ましくは２０〜５０重量％である。 As the fibrous material in the present invention, para-type wholly aromatic polyamide fibers and copolymers thereof, aromatic polyester fibers, polybenzazole fibers, meta-type aramid fibers and copolymers thereof, acrylic fibers, polyimide fibers, polyamide fibers Pulp-like fibers with highly fibrillated organic synthetic fibers such as para-type wholly aromatic polyamide fibers are highly fibrillated aramid pulp (hereinafter para-type wholly aromatic polyamide fibers are highly fibrillated) Aramid pulp is simply referred to simply as aramid pulp). These fibrous materials can be used singly or in combination, and the type, form, combination, blending ratio, etc. are not particularly limited, but considering heat resistance and papermaking properties, aramid pulp It is preferable to contain. In addition, low-fibrillated aramid pulp and short fibers without fibrils outside the scope of claims can be mixed and used as long as the effect is not impaired. The blending amount of the fibrous material is 10 to 70% by weight, preferably 15 to 60% by weight, and more preferably 20 to 50% by weight.
本発明の高度にフィブリル化したパルプとは、比表面積が３〜２０ｍ２／ｇの高度にフィブリル化したものを意味し、比表面積が３ｍ２／ｇ未満ではプラズマ処理の効果が少なくまた無機フィラー、摩擦調整剤と湿式抄造が困難となるばかりでなく、紙状物中から無機フィラーや摩擦調整剤が脱落することが懸念され、比表面積が２０ｍ２／ｇを超えるものは製造上困難で、また湿式抄造時に絡まりやすく固まりが生じるため好ましくない。 The highly fibrillated pulp of the present invention means those having a specific surface area is highly fibrillated 3 to 20 m 2 / g, also a specific surface area of less effect of the plasma treatment is less than 3m 2 / g inorganic filler In addition, it becomes difficult not only to make a friction modifier and wet papermaking but also to cause the inorganic filler and the friction modifier to fall out of the paper-like material, and those having a specific surface area exceeding 20 m 2 / g are difficult to manufacture. Further, it is not preferred because it tends to be entangled during wet papermaking and a lump is formed.
高度にフィブリル化したパルプとしては、例えばパラ型アラミド短繊維をリファイナーやビーター、ミル、高圧ホモジナイザー、摩砕装置等の装置により繊維に衝撃を与えて叩解し、フィブリル化させたアラミドパルプを挙げることが出来る。比表面積は繊維に与える衝撃の程度で調整することが出来る。 Examples of highly fibrillated pulp include aramid pulp that has been fibrillated by impacting the fibers with para-aramid short fibers by means of refiners, beaters, mills, high-pressure homogenizers, grinding devices, etc. I can do it. The specific surface area can be adjusted by the degree of impact applied to the fiber.
本発明における無機フィラーは、摩擦性能調整や固体潤滑等を目的に添加され、例えば硫酸バリウム、炭酸カルシウム、炭酸マグネシウム、炭化ケイ素、炭化チタン、アルミナ、シリカ、カシューダスト、珪藻土、グラファイト、タルク、カオリン、酸化マグネシウムなどを単一または複数種組み合わせて用いることができ、その種類や形態、粒径、組合せ、配合比率等は特に限定されるものではなく、その配合量としては、３０〜８０重量％、好ましくは３５〜７０重量％、さらに好ましくは４０〜６０重量％である。 The inorganic filler in the present invention is added for the purpose of adjusting friction performance, solid lubrication, etc., for example, barium sulfate, calcium carbonate, magnesium carbonate, silicon carbide, titanium carbide, alumina, silica, cashew dust, diatomaceous earth, graphite, talc, kaolin. Magnesium oxide and the like can be used singly or in combination, and the type, form, particle size, combination, blending ratio and the like are not particularly limited, and the blending amount is 30 to 80% by weight. , Preferably 35 to 70% by weight, more preferably 40 to 60% by weight.
本発明における結合剤樹脂としては、フェノール樹脂やメラミン樹脂およびその変性体等、摩擦材に一般的に用いられる熱硬化性樹脂をそのまま使用することができ、その種類や変性方法等は特に限定されるものではない。紙状物への含浸を行うために液状のものが最も好ましい。紙状物への含浸量としては、紙状物に対して２０〜６０重量％、好ましくは２５〜５５重量％、さらに好ましくは３０〜５０重量％である。 As the binder resin in the present invention, thermosetting resins generally used for friction materials, such as phenol resins and melamine resins and modified products thereof, can be used as they are, and their types and modification methods are particularly limited. It is not something. The liquid form is most preferred for impregnating paper. The amount of impregnation into the paper-like material is 20 to 60% by weight, preferably 25 to 55% by weight, more preferably 30 to 50% by weight, based on the paper-like material.
次に、本発明の方法を説明する。
本発明における湿式摩擦材の製造工程として、まず原料のスラリーを調製する。このスラリーの水への投入順序等に特に規定はなく、繊維状材料や無機フィラーなどを水へ投入し、主に繊維状材料を開繊するとともに均一なスラリーを調製する目的で、例えばナイアガラビーターやディスクリファイナーなどの公知の叩解機を用いて叩解する。なお、叩解により形状が変わるなどの支障がある材料の場合は、繊維状材料等を予め叩解した後に添加し混合しても特に差し支えない。また叩解を行わなくても、公知の離解機やミキサーを利用する方法で配合物の開繊や分散が十分達成される場合は、必ずしも叩解を行う必要はない。
Next, the method of the present invention will be described.
As a manufacturing process of the wet friction material in the present invention, first, a raw material slurry is prepared. There is no particular restriction on the order in which the slurry is poured into water. For example, a Niagara beater is used for the purpose of feeding a fibrous material or an inorganic filler into water, mainly opening the fibrous material and preparing a uniform slurry. Beat using a known beater such as a disc refiner. In addition, in the case of a material having a hindrance such as a shape change by beating, there is no problem even if a fibrous material or the like is added after being beaten in advance and mixed. Further, even if the beating is not performed, it is not always necessary to perform beating if the compound is sufficiently opened and dispersed by a method using a known disintegrator or mixer.
次に、このスラリーに叩解時に添加しなかった材料を投入し混合する。混合は、パルパーなどの公知のミキサーを用いることができる。これらの工程で、混合や叩解の際、気泡の発生を抑制する目的で、一般の抄造の際に用いられる公知の消泡剤を用いることができる。また、無機フィラーの繊維状材料への定着率を向上させる目的で、スラリーのｐＨを調整するｐＨ調整剤や、一般の抄造の際に用いられる定着剤を適宜用いたりすることができる。このような抄造の過程で添加する消泡剤やｐＨ調整剤、定着剤の種類や化学構造などは特に限定されるものではない。 Next, the material not added at the time of beating is added to the slurry and mixed. For the mixing, a known mixer such as a pulper can be used. In these steps, a known antifoaming agent used in general papermaking can be used for the purpose of suppressing the generation of bubbles during mixing and beating. Further, for the purpose of improving the fixing rate of the inorganic filler to the fibrous material, a pH adjusting agent for adjusting the pH of the slurry and a fixing agent used in general papermaking can be appropriately used. There are no particular restrictions on the type or chemical structure of the antifoaming agent, pH adjuster, fixing agent, etc. added during the papermaking process.
次に、このスラリーを抄造し、紙状物を得る。抄造は、長網抄紙機や丸網抄紙機といった連続抄紙機や、ＴＡＰＰＩ箱型抄紙機などのバッチ式抄紙機といった公知の抄造装置を用いて抄造することができ、また抄造後、連続抄紙機の場合はそのまま乾燥工程を経てローラーへ巻き取る。箱型抄紙機などのバッチ式での抄紙機の場合は、抄造後の紙を金枠等に保持し、乾燥機などで乾燥する。乾燥温度は、水が十分に除去できる温度であれば特に制限は無いが、原料の劣化等を考慮すると、８０℃〜１５０℃が好ましいが、この温度に限定されるものではない。乾燥後の紙状物は必要に応じて適宜任意の形状に裁断する。 Next, the slurry is made to obtain a paper-like material. Paper making can be carried out using a known paper making apparatus such as a continuous paper machine such as a long paper machine or a round paper machine, or a batch paper machine such as a TAPPI box paper machine. In the case of, it winds up to a roller through a drying process as it is. In the case of a batch type paper machine such as a box type paper machine, the paper after the paper making is held on a metal frame or the like and dried with a dryer or the like. The drying temperature is not particularly limited as long as it is a temperature at which water can be sufficiently removed. However, considering the deterioration of the raw material and the like, it is preferably 80 ° C. to 150 ° C., but is not limited to this temperature. The paper-like material after drying is appropriately cut into an arbitrary shape as necessary.
次に得られた紙状物に対して、プラズマ処理を行う。ここで言うプラズマ処理とは、ある一定の圧力、ある種の雰囲気ガスを充填した環境下において、一対の電極の少なくとも一方の対向面に固体誘電体を設置し、この一対の電極間にパルス状の電界を印加させることによりプラズマを発生させ、このように発生したプラズマで処理を行うことを言う。
プラズマ処理における圧力条件は特に限定されるものではないが、処理の安全性、簡易性、装置を小型化できるなどの観点から常圧下またはその近傍で行うことが好ましい。ここで言う常圧下とは、１気圧、即ち１０１３００Ｐａのことを指す。
Next, a plasma treatment is performed on the obtained paper-like material. The plasma treatment referred to here is a solid dielectric placed on at least one opposing surface of a pair of electrodes in an environment filled with a certain pressure and a certain kind of atmospheric gas, and a pulse shape is formed between the pair of electrodes This means that plasma is generated by applying the electric field, and processing is performed using the generated plasma.
The pressure condition in the plasma processing is not particularly limited, but it is preferably performed under normal pressure or in the vicinity thereof from the viewpoints of processing safety, simplicity, and downsizing of the apparatus. The term “under normal pressure” as used herein refers to 1 atm, that is, 101300 Pa.
本発明のプラズマ処理における雰囲気ガスは、例えば、酸素、窒素、水素、アンモニウム、エタン、空気、ヘリウム、ネオン、アルゴン、クリプトン、キセノン、ブタジエン、エチレン、アセチレンなどが挙げられ、これを単一または２種類以上を混合して用いることができる。中でも本発明においては、酸素を単一で用いることが最も好ましい。その理由は定かではないが、紙状物を酸素プラズマで処理することにより、紙状物中の特に有機物の繊維状材料がより効果的に化学修飾され、その結果として後に含浸する結合剤樹脂との間に化学結合を形成しやすくなるものと考えられる。 Examples of the atmospheric gas in the plasma treatment of the present invention include oxygen, nitrogen, hydrogen, ammonium, ethane, air, helium, neon, argon, krypton, xenon, butadiene, ethylene, acetylene, and the like. A mixture of more than one can be used. Among them, in the present invention, it is most preferable to use oxygen alone. The reason for this is not clear, but by treating the paper with oxygen plasma, the organic fibrous material in the paper is particularly effectively chemically modified, resulting in a binder resin that is subsequently impregnated with It is considered that a chemical bond is easily formed between the two.
プラズマ処理条件としては下記を満足する条件が好ましい。
５０≦周波数（ｋＨｚ）×処理時間（秒）≦２０００
As the plasma treatment conditions, conditions satisfying the following are preferable.
50 ≦ frequency (kHz) × processing time (seconds) ≦ 2000
上記範囲でプラズマ処理におけるパルスの周波数は、１〜３０ｋＨｚ、好ましくは５〜２５ｋＨｚ、更に好ましくは１０〜２０ｋＨｚである。パルスの周波数が１ｋＨｚ未満の場合、処理時間を十分に要したとしても紙状物の処理を効果的に行うことができず、またパルプの周波数が３０ｋＨｚを超える場合、僅かな処理時間であったとしても処理が強すぎるために、紙状物の著しい劣化が生じる可能性がある。 In the above range, the frequency of the pulse in the plasma treatment is 1 to 30 kHz, preferably 5 to 25 kHz, and more preferably 10 to 20 kHz. When the frequency of the pulse is less than 1 kHz, even if the processing time is sufficiently long, the paper-like material cannot be processed effectively, and when the frequency of the pulp exceeds 30 kHz, the processing time is short. However, since the treatment is too strong, the paper-like material may be significantly deteriorated.
又プラズマ処理の処理時間は、上記範囲内に入るように決定することが出来るが、１０〜１８０秒、好ましくは２０〜１２０秒、更に好ましくは３０〜９０秒である。処理時間が１０秒未満の場合、紙状物の処理を十分且つ均一に行うことができないために結合剤樹脂との高い接着性が得られず、また１８０秒を超える場合は、紙状物中の繊維状材料が著しく劣化する危険性がある。 The treatment time of the plasma treatment can be determined so as to fall within the above range, but is 10 to 180 seconds, preferably 20 to 120 seconds, and more preferably 30 to 90 seconds. If the treatment time is less than 10 seconds, the paper-like material cannot be sufficiently and uniformly treated, so that high adhesiveness with the binder resin cannot be obtained, and if it exceeds 180 seconds, There is a risk that the fibrous material of the present invention will deteriorate significantly.
本発明における紙状物のプラズマ処理は、基本的にはバッチ式で行うが、装置の改良等により連続処理によっても行うことができる。
本発明のプラズマ処理に用いる装置は、市販のものをそのまま、または必要に応じて安全性を十分に考慮した上で一部改良したものを用いることができる。
The plasma treatment of the paper-like material in the present invention is basically carried out in a batch system, but can also be carried out by continuous treatment by improving the apparatus.
As the apparatus used for the plasma treatment of the present invention, a commercially available apparatus can be used as it is or a partly improved apparatus in consideration of safety as required.
なお、プラズマ処理を行った紙状物は、特に有機繊維状材料が化学修飾されているため、この化学修飾が経時的に失活するため、プラズマ処理後、２４時間以内に次の工程である結合剤樹脂の含浸を行うことが好ましく、またプラズマ処理後直ちに結合剤樹脂を含浸することがより好ましい。 In addition, since the organic fibrous material is chemically modified especially in the paper-like material subjected to the plasma treatment, this chemical modification is deactivated with time, so that the next step is within 24 hours after the plasma treatment. It is preferable to impregnate the binder resin, and it is more preferable to impregnate the binder resin immediately after the plasma treatment.
次にプラズマ処理を行った紙状物へ、結合剤樹脂溶液を含浸する。紙状物への結合剤樹脂溶液の含浸方法としては、スプレーなどの噴霧器により吹き付ける方法、紙状物を結合剤樹脂が入った浴へディップする方法などあるが、これらの方法に限定されるものではなく、紙状物へ結合剤樹脂溶液を均一に含浸できる手法であれば、特に差し支えない。その後、結合剤樹脂溶液を含浸した紙状物から揮発成分を除去しプリプレグを作製する。揮発成分を除去する方法には特に規定はなく、室温以上で且つ結合剤樹脂の硬化が著しく進行しない程度の温度以下であれば、特に問題はない。ただこの過程で、紙状物中で結合剤樹脂のマイグレーションが起こり、紙状物中の結合剤樹脂の分布が不均一になることがあるため、注意が必要である。 Next, the paper resin subjected to the plasma treatment is impregnated with the binder resin solution. Examples of the impregnation method of the binder resin solution into the paper-like material include a method of spraying with a sprayer such as a spray, a method of dipping the paper-like material into a bath containing the binder resin, and the like. However, any technique that can uniformly impregnate the binder resin solution into the paper-like material may be used. Thereafter, the volatile component is removed from the paper-like material impregnated with the binder resin solution to prepare a prepreg. There is no particular limitation on the method for removing the volatile component, and there is no particular problem as long as the temperature is not lower than room temperature and not higher than the temperature at which the binder resin is not significantly cured. However, care must be taken because the binder resin migrates in the paper-like material during this process, and the distribution of the binder resin in the paper-like material may become uneven.
その後、プリプレグを加熱プレスする。プリプレグの加熱プレスの方法としては、特に規定はなく、公知のプレス機などを用いることにより行うことができる。このときの、プレス温度やプレス圧、加圧・加熱時間については特に規定はなく、用いた結合剤樹脂の組成や硬化温度、また最終の湿式摩擦材の厚みや気孔率等を考慮した条件で行えば特に問題はない。更に、その後結合剤樹脂を完全に硬化させる目的で、後硬化を行うこともできる。この後硬化条件については、特に規定はなく用いた結合剤樹脂の硬化温度等を考慮して適宜決定して差し支えない。 Thereafter, the prepreg is heated and pressed. The method for heating and pressing the prepreg is not particularly limited, and can be performed by using a known press machine or the like. At this time, the press temperature, press pressure, pressurizing / heating time are not particularly specified, and the conditions are in consideration of the composition and curing temperature of the binder resin used and the thickness and porosity of the final wet friction material. If it does, there is no problem. Further, after-curing can be performed for the purpose of completely curing the binder resin. The post-curing conditions are not particularly defined and may be appropriately determined in consideration of the curing temperature of the binder resin used.
そして得られた湿式摩擦材は、必要に応じて任意の大きさや形状に裁断し、金属製のディスクに接着してクラッチフェーシングなどに用いることができる。なお、熱プレスを行う前のプリプレグを任意の大きさや形状に裁断し、金属製のディスク上で加熱・加圧して結合剤樹脂を硬化させるとともにディスクに直接接着させることもできる。 The obtained wet friction material can be cut into an arbitrary size or shape as necessary, and can be bonded to a metal disk for use in clutch facing or the like. The prepreg before hot pressing can be cut into an arbitrary size and shape, and heated and pressed on a metal disk to cure the binder resin and directly adhere to the disk.
本実施例に使用した物性項目の測定法は下記の通りで行った。
１）気孔率
表１に記載した各配合物の比重、および得られた湿式摩擦材の厚み、面積などから湿式摩擦材中の固体体積分率（ｖｏｌ％、以下Ｖｓと記載）を下記（１）式より算出し、更に（２）式の通り気孔率を算出した。
（１）Ｖｓ（ｖｏｌ％）＝１０００×Σ（Ｗｎ／ρｎ）／Ｔ×Ｓ
Ｗｎ：各配合物の仕込み重量（ｇ）
ρｎ：各配合物の比重
Ｔ：得られた湿式摩擦材の厚さ
Ｓ：得られた湿式摩擦材の面積
（２）気孔率（ｖｏｌ％）＝１００−Ｖｓ
The measurement method of physical property items used in this example was as follows.
1) Porosity The solid volume fraction (vol%, hereinafter referred to as Vs) in the wet friction material is described below (1) from the specific gravity of each formulation described in Table 1, the thickness and area of the obtained wet friction material, etc. ), And the porosity was further calculated according to equation (2).
(1) Vs (vol%) = 1000 × Σ (Wn / ρn) / T × S
Wn: Charge weight of each compound (g)
ρn: specific gravity of each compound
T: thickness of the obtained wet friction material
S: Area of the obtained wet friction material (2) Porosity (vol%) = 100−Vs
２）湿式摩擦材の引張強度
下記条件により引張強度および破断伸度を測定した。
温度：室温
試験機：ＩＮＳＴＲＯＮ ５５６５型（ＩＮＳＴＲＯＮ社製）を用い、平板形状のチャックに試験片を挟み引張試験を行った。
試験片：１００ｍｍ×１５ｍｍに裁断したしたものを試験片として用いた。
試験速度：１０ｍｍ／分
チャック間距離：６０ｍｍ
この測定結果を表１に示す。
2) Tensile strength of wet friction material Tensile strength and elongation at break were measured under the following conditions.
Temperature: Room temperature Tester: An INSTRON 5565 type (manufactured by INSTRON) was used, and a tensile test was conducted with a test piece sandwiched between flat plate-shaped chucks.
Test piece: A piece cut to 100 mm × 15 mm was used as a test piece.
Test speed: 10 mm / min Distance between chucks: 60 mm
The measurement results are shown in Table 1.
３）湿式摩擦材の引張剪断強度
下記の試験方法・条件で、得られた湿式摩擦材の引張剪断強度を測定した。
なお下記の通り得られた試験片は、片端を固定しもう片端を垂直に引張ることにより、湿式摩擦材を剪断破壊させて、引張り剪断強度を測定した。
試験機：ＩＮＳＴＲＯＮ ５５６５型（ＩＮＳＴＲＯＮ社製）
試験片：２０ｍｍ×２０ｍｍに切断した湿式摩擦材の片面を、２０ｍｍ×１００ｍｍのサンドブラスト板の端に、市販の２液型エポキシ系接着剤を用いて接着させた。続いてもう片方の面も同様に接着剤でサンドブラスト板に接着させて試験片を得た。
温度：室温
ゲージ間距離：２５ｍｍ
引張速度：１０ｍｍ／分
この測定結果を表１に示す。
3) Tensile shear strength of wet friction material The tensile shear strength of the obtained wet friction material was measured by the following test method and conditions.
The test piece obtained as described below was subjected to shear fracture of the wet friction material by fixing one end and pulling the other end vertically, and the tensile shear strength was measured.
Testing machine: INSTRON 5565 type (manufactured by INSTRON)
Test piece: One side of a wet friction material cut to 20 mm × 20 mm was bonded to the end of a 20 mm × 100 mm sandblast plate using a commercially available two-component epoxy adhesive. Subsequently, the other surface was similarly bonded to a sandblast plate with an adhesive to obtain a test piece.
Temperature: Room temperature Gauge distance: 25mm
Tensile speed: 10 mm / min Table 1 shows the measurement results.
４）耐熱性試験
空気雰囲気下、２５０℃で、１００時間で熱処理を行った後、２）、３）と同じ方法で引張強度および引張剪断強度を測定した。この測定結果を表１に示す。
以下に本発明を実施例に基づき具体的に説明する。なお本発明はこれらに限定されるものではない。
4) Heat resistance test After heat treatment in an air atmosphere at 250 ° C for 100 hours, tensile strength and tensile shear strength were measured by the same method as 2) and 3). The measurement results are shown in Table 1.
The present invention will be specifically described below based on examples. The present invention is not limited to these.
［実施例１］
繊維状材料としては、ポリ−ｐ−フェニレンテレフタルアミド繊維を高度にフィブリル化させたアラミドパルプ（商品名「トワロン１０９７」、帝人トワロン製、比表面積：５．８ｍ２／ｇ、長さ加重平均繊維長：０．９５ｍｍ）、無機フィラーとしては、珪藻土（商品名「ラヂオライト＃２００」昭和化学工業製）、摩擦調整材としては、カシューダスト（カシュー製）を、それぞれ表１のような組成で配合したスラリーを調製し、定着剤、消泡剤、ｐＨ調整剤を添加した後、これを抄造し乾燥後、紙状物を得た。次にこの紙状物を、常圧下、酸素ガス雰囲気で、パルプ周波数を１５ｋＨｚにし、処理時間を６０秒としてプラズマ処理を行った。処理を行って３０分後、プラズマ処理を行った紙状物に対し、結合剤樹脂として、レゾール型フェノール樹脂（商品名「スミライトレジン ＰＲ−５３１２３」、住友ベークライト製、固形分濃度：４５％）をメタノールで固形分濃度：１５％となるように希釈したものにディップして含浸した。そして、室温で一昼夜乾燥してプリプレグを得た。
[Example 1]
As a fibrous material, aramid pulp (trade name “Twaron 1097”, manufactured by Teijin Twaron, specific surface area: 5.8 m 2 / g, length-weighted average fiber, which is a highly fibrillated poly-p-phenylene terephthalamide fiber (Length: 0.95 mm), inorganic filler as diatomaceous earth (trade name “Radiolite # 200” manufactured by Showa Chemical Industry), and friction modifier as cashew dust (manufactured by cashew) with the compositions shown in Table 1, respectively. A blended slurry was prepared, and after adding a fixing agent, an antifoaming agent and a pH adjuster, this was made into paper and dried to obtain a paper. Next, this paper-like material was subjected to plasma treatment under normal pressure in an oxygen gas atmosphere with a pulp frequency of 15 kHz and a treatment time of 60 seconds. Thirty minutes after the treatment, the paper-like material subjected to the plasma treatment was treated with a resol type phenol resin (trade name “Sumilite Resin PR-53123”, manufactured by Sumitomo Bakelite, solid content concentration: 45%) as a binder resin. ) Was impregnated by dipping into methanol diluted to a solid content concentration of 15%. And it dried at room temperature all day and night, and obtained the prepreg.
その後、このプリプレグを、プレス機を用いて１８０℃で５分間、面圧：６×１０３ｋＰａで熱プレスを行った。この際、厚みを調節するために、厚み：０．５０ｍｍのスペーサーを挿入してプレスした。更にプレス後、１８０℃で２時間後硬化を行い、湿式摩擦材を得た。得られた湿式摩擦材の目付けは、３３０ｇ／ｍ２、厚みは０．４９ｍｍ、気孔率は５５ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。酸素プラズマで処理を行った紙状物を用いることにより、後に示すプラズマ処理を行っていない比較例１に比べ、特に引張剪断強度が大きく向上した。更に、耐熱性試験後も引張強度、引張剪断強度ともに強度保持率が８０％以上と高い数値を示した。これは、紙状物に酸素プラズマ処理を行うことにより、紙状物中の特に有機成分が化学修飾され、接着力の増大することにより機械的物性、特に引張せん断力の大幅な向上が見られたと考えられる、更に、セルロースパルプのような耐熱性の低い成分を含んでいないため、耐熱試験後も高い強度保持率を示したものと考えられる。 Thereafter, this prepreg was hot-pressed at 180 ° C. for 5 minutes at a surface pressure of 6 × 103 kPa using a press machine. At this time, in order to adjust the thickness, a spacer having a thickness of 0.50 mm was inserted and pressed. Further, after pressing, post-curing was performed at 180 ° C. for 2 hours to obtain a wet friction material. The basis weight of the obtained wet friction material was 330 g / m 2 , the thickness was 0.49 mm, and the porosity was 55 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. By using a paper-like material treated with oxygen plasma, particularly the tensile shear strength was greatly improved as compared with Comparative Example 1 in which plasma treatment described later was not performed. Furthermore, even after the heat resistance test, the tensile strength and tensile shear strength both showed high values of 80% or more. This is because when oxygen plasma treatment is performed on the paper-like material, particularly organic components in the paper-like material are chemically modified, and by increasing the adhesive force, mechanical properties, particularly tensile shear force, are greatly improved. Furthermore, since it does not contain a component having low heat resistance such as cellulose pulp, it is considered that high strength retention was exhibited even after the heat test.
［実施例２］
実施例１と同様の組成および手順により、紙状物を作製した。その後、雰囲気ガスを窒素ガスに変えたこと以外は実施例１と同じ条件で紙状物のプラズマ処理を行った。そして得られた紙状物を実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３２６ｇ／ｍ２、厚みは０．４８ｍｍ、気孔率は５４ｖｏｌ％であった。この摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。酸素プラズマほどの効果は見られないものの、後に示すプラズマ処理を行っていない比較例１に比べ、特に引張剪断強度の向上が見られた。また耐熱性試験後も引張強度、引張剪断強度ともに強度保持率が８０％以上と高い数値を示した。これは、実施例１の場合と同様、プラズマ処理により紙状物中の有機物が化学修飾されたことにより、接着力が増大することにより、機械的物性、特に引張せん断力の大幅な向上が見られたと考えられる。
[Example 2]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, the paper-like material was plasma-treated under the same conditions as in Example 1 except that the atmospheric gas was changed to nitrogen gas. A wet friction material was produced from the obtained paper-like material according to the same formulation as in Example 1. The basis weight of the obtained wet friction material was 326 g / m 2 , the thickness was 0.48 mm, and the porosity was 54 vol%. The friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under a room temperature and air atmosphere. The obtained results are shown in Table 1. Although not as effective as oxygen plasma, an improvement in the tensile shear strength was particularly observed as compared with Comparative Example 1 in which the plasma treatment described later was not performed. Even after the heat resistance test, the tensile strength and tensile shear strength both showed high values of 80% or more. As in the case of Example 1, the organic material in the paper-like material was chemically modified by the plasma treatment, and the adhesive force increased, so that the mechanical properties, particularly the tensile shear force, were greatly improved. It is thought that it was done.
［比較例１］
実施例１と同様の組成および手順により、紙状物を作製した。その後、プラズマ処理を行わない点以外は、実施例１と同じ処方で湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３２７ｇ／ｍ２、厚みは０．４９ｍｍ、気孔率は５４ｖｏｌ％であった。この摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。耐熱試験後の強度保持率は、８０％以上と高い値を示したが、引張強度および引張剪断強度の絶対値は実施例１、２と比較すると低い値であった。これは、紙状物中のアラミド繊維が非常に不活性であるため、結合剤樹脂との界面接着が弱く、プラズマ処理を行った場合に比べ物性が低くなったものと考えられる。
[Comparative Example 1]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, a wet friction material was prepared with the same formulation as Example 1 except that the plasma treatment was not performed. The basis weight of the obtained wet friction material was 327 g / m 2 , the thickness was 0.49 mm, and the porosity was 54 vol%. The friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under a room temperature and air atmosphere. The obtained results are shown in Table 1. The strength retention after the heat test was as high as 80% or higher, but the absolute values of the tensile strength and the tensile shear strength were lower than those in Examples 1 and 2. This is presumably because the aramid fibers in the paper-like material are very inactive, so the interfacial adhesion with the binder resin is weak, and the physical properties are lower than when plasma treatment is performed.
［比較例２］
実施例１で用いたアラミドパルプの一部をセルロースパルプで置き換え、配合量をそれぞれ表１のように調節したこと以外は、実施例１と同じ手順で紙状物を作製した。その後、プラズマ処理を行わない点以外は、実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３３１ｇ／ｍ２、厚みは０．４８ｍｍ、気孔率は５５ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。熱処理を行う前の引張強度および引張剪断強度は、セルロースパルプを含まない比較例１に比べ、高い値であり、プラズマ処理を行った実施例１、２と同等の値であった。しかし、耐熱試験後の機械的物性は、他に比べ明らかに低下しており、強度保持率は約６３％であった。これは、活性が高く、また結合剤樹脂との馴染みが良いセルロースパルプを加えることで、結合剤樹脂と紙状物との接着性が向上し、その結果として特に引張剪断強度において比較例１に比べて向上が見られたと考えられる。しかしながら、セルロースパルプを加えることで耐熱性は低下するため、熱処理によりセルロースパルプの分解や強度劣化が起こり、その結果として、セルロースパルプを加えなかった他の例に比べ明らかに強度保持率の低下が大きくなったものと考えられる。
[Comparative Example 2]
A paper-like material was prepared in the same procedure as in Example 1 except that a part of the aramid pulp used in Example 1 was replaced with cellulose pulp and the blending amounts were adjusted as shown in Table 1, respectively. Thereafter, a wet friction material was prepared according to the same formulation as in Example 1 except that the plasma treatment was not performed. The basis weight of the obtained wet friction material was 331 g / m 2 , the thickness was 0.48 mm, and the porosity was 55 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. The tensile strength and tensile shear strength before the heat treatment were higher than those in Comparative Example 1 that did not contain cellulose pulp, and were equivalent to those in Examples 1 and 2 where the plasma treatment was performed. However, the mechanical properties after the heat test were clearly reduced compared to the others, and the strength retention was about 63%. This is because the addition of cellulose pulp having high activity and good compatibility with the binder resin improves the adhesion between the binder resin and the paper-like material. It is thought that an improvement was seen in comparison. However, the heat resistance is reduced by adding cellulose pulp, so decomposition and strength degradation of cellulose pulp occur due to heat treatment, and as a result, the strength retention rate is clearly reduced compared to other examples where cellulose pulp was not added. It seems that it has grown.
［比較例３］
実施例１と同様の組成および手順により、紙状物を作製した。その後、パルスの周波数を０．８ｋＨｚとしたこと以外は実施例１と同じ条件で紙状物のプラズマ処理を行った。そして得られた紙状物を実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３３２ｇ／ｍ２、厚みは０．４９ｍｍ、気孔率は５５ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。プラズマ処理を行ったにもかかわらず、実施例１，２のような機械的物性の向上は見られず、プラズマ処理を行わなかった比較例１とほぼ同等の値となった。これは、パルスの周波数が低く、紙状物中の有機物の化学修飾がほとんど起こらなかったものと考えられる。
[Comparative Example 3]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, the paper material was plasma-treated under the same conditions as in Example 1 except that the pulse frequency was 0.8 kHz. A wet friction material was produced from the obtained paper-like material according to the same formulation as in Example 1. The basis weight of the obtained wet friction material was 332 g / m 2 , the thickness was 0.49 mm, and the porosity was 55 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. Although the plasma treatment was performed, no improvement in mechanical properties as in Examples 1 and 2 was observed, and the values were almost the same as those in Comparative Example 1 in which the plasma treatment was not performed. This is probably because the pulse frequency was low and almost no chemical modification of the organic matter in the paper-like material occurred.
［比較例４］
実施例１と同様の組成および手順により、紙状物を作製した。その後、パルスの周波数を３５ｋＨｚとしたこと以外は実施例１と同じ条件で紙状物のプラズマ処理を行った。そして得られた紙状物を実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３２７ｇ／ｍ２、厚みは０．４８ｍｍ、気孔率は５４ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。プラズマ処理を行ったにもかかわらず、処理を行わなかった場合と比較しても機械的物性は明らかに低下した。これは、プラズマ処理により化学修飾されたものの、パルス周波数が高すぎたため、特に繊維状材料の著しい強度劣化が起こったことが原因と考えられる。
[Comparative Example 4]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, the paper material was plasma-treated under the same conditions as in Example 1 except that the pulse frequency was set to 35 kHz. A wet friction material was produced from the obtained paper-like material according to the same formulation as in Example 1. The basis weight of the obtained wet friction material was 327 g / m 2 , the thickness was 0.48 mm, and the porosity was 54 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. Even though the plasma treatment was performed, the mechanical properties were clearly reduced as compared with the case where the treatment was not performed. Although this was chemically modified by the plasma treatment, the pulse frequency was too high, so that the strength of the fibrous material was particularly severely deteriorated.
［比較例５］
実施例１と同様の組成および手順により、紙状物を作製した。その後、処理時間を５秒としたこと以外は実施例１と同じ条件で紙状物のプラズマ処理を行った。そして得られた紙状物を実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３３０ｇ／ｍ２、厚みは０．４９ｍｍ、気孔率は５５ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。その結果、比較例１と比較して、ほとんど機械的物性の向上は見られなかった。これは、比較例３と同様、プラズマ処理を行ったものの、処理時間が短すぎたために紙状物中の有機物の化学修飾がほとんど起こらなかったものと考えられる。
[Comparative Example 5]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, the plasma treatment of the paper-like material was performed under the same conditions as in Example 1 except that the treatment time was 5 seconds. A wet friction material was produced from the obtained paper-like material according to the same formulation as in Example 1. The basis weight of the obtained wet friction material was 330 g / m 2 , the thickness was 0.49 mm, and the porosity was 55 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. As a result, the mechanical properties were hardly improved as compared with Comparative Example 1. It can be considered that, as in Comparative Example 3, the plasma treatment was performed, but the chemical modification of the organic matter in the paper-like material hardly occurred because the treatment time was too short.
［比較例６］
実施例１と同様の組成および手順により、紙状物を作製した。その後、処理時間を２００秒としたこと以外は実施例１と同じ条件で紙状物のプラズマ処理を行った。そして得られた紙状物を実施例１と同じ処方により湿式摩擦材を作製した。得られた湿式摩擦材の目付けは、３３０ｇ／ｍ２、厚みは０．４９ｍｍ、気孔率は５５ｖｏｌ％であった。この湿式摩擦材の室温と空気雰囲気下、２５０℃で、１００時間で熱処理後の引張強度と引張剪断強度を測定した。得られた結果を表１に示す。その結果、比較例４と同様、プラズマ処理を行ったにもかかわらず著しい機械的物性の低下が見られた。これは、プラズマ処理を行う時間が長すぎたために、特に繊維状材料の著しい強度劣化が起こったことが原因と考えられる。
[Comparative Example 6]
A paper-like product was produced by the same composition and procedure as in Example 1. Thereafter, the plasma treatment of the paper-like material was performed under the same conditions as in Example 1 except that the treatment time was 200 seconds. A wet friction material was produced from the obtained paper-like material according to the same formulation as in Example 1. The basis weight of the obtained wet friction material was 330 g / m 2 , the thickness was 0.49 mm, and the porosity was 55 vol%. The wet friction material was measured for tensile strength and tensile shear strength after heat treatment at 250 ° C. for 100 hours under room temperature and air atmosphere. The obtained results are shown in Table 1. As a result, as in Comparative Example 4, a significant decrease in mechanical properties was observed despite the plasma treatment. This is presumably because the strength of the fibrous material was significantly deteriorated because the time for performing the plasma treatment was too long.
このように、紙状物を特定の条件でプラズマ処理することにより、耐熱性を低下させることなく機械的物性が大幅に向上したが、その反面、適切でない条件でプラズマ処理を行った場合は、機械的物性の向上は全く見られないばかりか、条件によっては大幅な強度低下がもたらされる。これは、プラズマ処理という高エネルギーにより紙状物中の特に繊維状物が活性化されるが、その反面、その繊維状材料の著しい劣化ももたらされるためである。 As described above, by performing plasma treatment on a paper-like material under specific conditions, mechanical properties have been greatly improved without reducing heat resistance, but on the other hand, when plasma treatment is performed under inappropriate conditions, Not only mechanical properties are not improved at all, but also a significant decrease in strength is caused depending on the conditions. This is because the high energy of the plasma treatment activates especially the fibrous material in the paper-like material, but on the other hand, the fibrous material is also significantly deteriorated.
自動車等の自動変速機における動力伝達系のクラッチフェーシングなどの湿式摩擦材として特に有用である。 It is particularly useful as a wet friction material for clutch facing of a power transmission system in an automatic transmission such as an automobile.
Claims (4)
８０≦周波数（ｋＨｚ）×処理時間（秒）≦２０００ In a wet friction material mainly composed of a fibrous material, an inorganic filler, a friction modifier, and a binder resin, the fibrous material is formed by subjecting highly fibrillated pulp-like fibers to plasma treatment, and the plasma treatment is performed. A wet friction material characterized by satisfying the following conditions.
80 ≦ frequency (kHz) × processing time (seconds) ≦ 2000
５０≦周波数（ｋＨｚ）×処理時間（秒）≦２０００ As a fibrous material, a paper-like material obtained by wet-making a water-based slurry composed of a highly fibrillated para-type wholly aromatic polyamide, an inorganic filler, and a friction modifier, satisfying the following conditions A method for producing a wet friction material, characterized by impregnating with a binder resin after plasma treatment in step (b).
50 ≦ frequency (kHz) × processing time (seconds) ≦ 2000
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190043537A (en) * | 2016-08-24 | 2019-04-26 | 데이진 아라미드 비.브이. | Friction material containing aramid |
| JP2022527071A (en) * | 2019-03-25 | 2022-05-30 | シェフラー テクノロジーズ アー・ゲー ウント コー． カー・ゲー | Flexible wet friction material containing silane |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190043537A (en) * | 2016-08-24 | 2019-04-26 | 데이진 아라미드 비.브이. | Friction material containing aramid |
| JP2019534954A (en) * | 2016-08-24 | 2019-12-05 | テイジン・アラミド・ビー．ブイ．Ｔｅｉｊｉｎ Ａｒａｍｉｄ Ｂ．Ｖ． | Aramid-containing friction material |
| KR102513052B1 (en) * | 2016-08-24 | 2023-03-24 | 데이진 아라미드 비.브이. | Friction material containing aramid |
| JP2022527071A (en) * | 2019-03-25 | 2022-05-30 | シェフラー テクノロジーズ アー・ゲー ウント コー． カー・ゲー | Flexible wet friction material containing silane |
| JP7309899B2 (en) | 2019-03-25 | 2023-07-18 | シェフラー テクノロジーズ アー・ゲー ウント コー． カー・ゲー | Flexible wet friction material containing silane |
| US11940028B2 (en) | 2019-03-25 | 2024-03-26 | Schaeffler Technologies AG & Co. KG | Flexible wet friction materials including silanes |
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