JP2004189883A - Elastomer composition, method for producing elastomer composition and paper feed roller using the elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastomer composition having low hardness and extremely excellent in wear resistance and to provide a method for producing the elastomer composition and to provide a paper feed roller realizing low hardness and good wear resistance, particularly excellent in wear resistance at the time of idle running. <P>SOLUTION: The method for producing the elastomer composition comprises a step for obtaining a thermoplastic resin composition component by kneading a mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer with an olefin-based resin with a compatibilizer (C) containing at least one of an acid-modified EPDM and an acid-modified hydrogenated styrene-based thermoplastic elastomer and a polyamide resin (D) and finely dispersing the polyamide resin (D) into the mixed composition (B) and a step for dynamically crosslinking the thermoplastic resin composition component and a rubber component (A) containing at least one of a diene-based rubber and an EPDM rubber. The roller part 1 of the paper feed roller 10 is formed by using the elastomer composition. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００５０】
・ゴム成分（Ａ）；ＥＰＤＭ：住友化学製 エスプレン６７０Ｆ（１００％油展）、ＩＩＲ：日本合成ゴム製 ブチルゴムｂｕｔｙｌ−２６８（非油展）
・混合組成物（Ｂ）；ＳＥＰＳ＋ＰＰ：クラレプラスチック製 ＳＥＰＳコンパウンド ＣＪＫ１（ＰＰ入り）（水素添加スチレン系熱可塑性エラストマー（ＳＥＰＳ）：オレフィン系樹脂（ＰＰ））＝（１００：３５）
・相容化剤（Ｃ）；カルボン酸変性ＳＥＢＳ：旭化成製 タフテック１９４３、カルボン酸変性ＥＰＤＭ：日本合成ゴム製 Ｔ７７４１Ｐ
・ポリアミド系樹脂（Ｄ）；ナイロン樹脂（ナイロン１１） ＰＡ１１
【００５１】
紙送りローラの具体的な製造方法を示す。
まず、材料の計量を行い、混合組成物（Ｂ）と、相容化剤（Ｃ）と、ポリアミド系樹脂（Ｄ）とをタンブラーにて室温で、１０分混合した後、２００℃で２軸押出機（アイベック製ＨＴＭ３８）にて熱可塑性組成分を作製し、押し出してペレット化した。
【００５２】
次に、材料計量を行い、熱可塑性組成分に、ゴム成分（Ａ）、及び樹脂架橋剤（田岡化学製、タッキロール２５０−ＩＩＩ）１２重量部、亜鉛華５重量部を配合し、タンブラーにて室温で１０分混合した後、２００℃で２軸押出機（アイベック製ＨＴＭ３８）にて動的架橋して熱可塑性エラストマー組成物を作製し、押し出してペレット化した。
【００５３】
このペレットを単軸押出機（笠松加工研究所製φ５０押出機、２０ｒｐｍ、温調１９０℃〜２３０℃）を用いてチューブ状に押し出し、外径２２ｍｍ、内径１８ｍｍの押出成形品を得た。このチューブ状押出成形品を１５ｍｍ幅に定寸カットし、チューブの中空部に芯金を挿入し紙送りローラとした。
【００５４】
（実施例１〜７）
表１に示すように、ゴム成分（Ａ）、混合組成物（Ｂ）、相容化剤（Ｃ）、ポリアミド系樹脂（Ｄ）を各々規定量配合した。上記のように、熱可塑性組成分を得る工程と、動的架橋を行う工程の２つの工程により製造した。
【００５５】
（比較例１〜４）
表１に示すように、比較例１は相容化剤（Ｃ）を用いなかった。比較例２は相容化剤（Ｃ）を少量とした。比較例３は相容化剤（Ｃ）を多量とした。比較例４はポリアミド系樹脂（Ｄ）を多量とした。製造方法は実施例と同様とした。
【００５６】
上記実施例及び比較例の紙送りローラについて、後述する方法により、摩耗減量、ゴム粉の発生の評価を行った。また、引張強度ＴＢ、硬度ＨＳの測定も行った。評価結果を表１に示す。
【００５７】
（引張強度）
インジェクションにて動的架橋組成物をシート状に成形し、ＪＩＳ−Ｋ６３０１に従い引張強度ＴＢを測定した。
【００５８】
（摩耗減量）
カット後の製品を径２０ｍｍの丸芯にはめて、荷重３００ｇをかけて１００ｒｐｍで分離部材（ゴム製シート）の上で空転させ、摩耗前後での重量減量（ｍｇ）を測定し、ゴム粉の発生具合を目視で確認した。摩耗減量は７ｍｇ以下を良好とした。
【００５９】
（硬度）
硬度ＨＳとは、ショアＡ硬度であり、ＪＩＳ Ｋ６３０１に基づいて測定を行った。
【００６０】
表１に示すように、実施例１〜８は、本発明のエラストマー組成物を用い、本発明のエラストマーの製造方法により製造された紙送りローラであり、引張強度が高いために、耐摩耗性に非常に優れ、摩耗減量が極めて少なかく、ゴム粉がほとんど発生しなかった。
【００６１】
一方、相容化剤を配合しなかった比較例１、相容化剤の配合量が少なかった比較例２は、引張強度が非常に低く、耐摩耗性に劣っており、摩耗減量が多く、ゴム粉が多く発生した。比較例３は、ポリアミド系樹脂が多かったため、硬度が高かった。
【００６２】
【発明の効果】
以上の説明より明らかなように、本発明によれば、ジエン系ゴム又はＥＰＤＭゴム、スチレン系熱可塑性エラストマーとオレフィン系樹脂の混合物に、酸変性物の相容化剤を使ってポリアミド系樹脂を分散させているため、硬度が低い上に、引張強度が高く、耐摩耗性に非常に優れたエラストマー組成物を得ることができる。
【００６３】
また、本発明の製造方法によれば、ポリアミド系樹脂（Ｄ）を混合組成物（Ｂ）中に分散させた熱可塑性組成分を得た後に、該熱可塑性組成分に樹脂架橋剤等の架橋剤とゴム成分（Ａ）を配合して動的架橋を行っているため、ゴム成分（Ａ）とポリアミド系樹脂（Ｄ）とが共に、マトリックス樹脂相中に均一に微分散され、特に引張強度を向上することができ、耐摩耗性に優れたエラストマー組成物を生産性良く製造することができる。
【００６４】
本発明は、以上のように、低硬度でありながら、引張強度ＴＢが高く、耐摩耗性の良いエラストマー組成物を得ることができる。よって、低硬度と良好な耐摩耗性を実現し、特に、高い物理的強度が必要な高荷重のかかる空転時の耐摩耗性に優れた紙送りローラを得ることができる。従って、インクジェットプリンター、レーザプリンター、静電式複写機、ファクシミリ装置等のＯＡ機器や、自動預金支払機（ＡＴＭ）等において紙・フィルム等を搬送する紙送り機構等い好適に用いることができる。
【図面の簡単な説明】
【図１】本発明の紙送りローラの概略図である。
【符号の説明】
１ ローラ部
２ 軸芯
１０ 紙送りローラ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an elastomer composition, a method for producing the elastomer composition, and a paper feed roller using the elastomer composition. More specifically, the present invention relates to an inkjet printer, a laser printer, The present invention relates to an elastomer composition suitably used as a paper feed roller used in OA equipment such as an electric copying machine and a facsimile machine and a paper feed mechanism such as an automatic teller machine (ATM) and a method for producing the same.
[0002]
[Prior art]
OA equipment such as inkjet printers, laser printers, electrostatic copiers, and facsimile machines, and paper feed mechanisms for transporting paper and films in automatic teller machines (ATMs) and the like include rubber compositions and elastomer compositions. Is used.
[0003]
In recent years, in particular, the number of OA devices for personal use has increased, and various types of paper have been passed. In order to obtain stable paper and film transportability even for various types of paper, it is high. It is required to secure wear resistance and a high coefficient of friction. Therefore, various proposals have been made for an elastomer composition, a rubber composition, and the like suitable for the above-described paper feed roller.
[0004]
For example, the applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. H11-228708, in order to obtain a large coefficient of friction with paper when used in a paper feed rubber roller and to have excellent abrasion resistance. The present invention proposes a rubber composition comprising 100 to 300 parts by weight of a hydrogenated styrene-based thermoplastic elastomer per part, and dynamically crosslinking the rubber with a resin crosslinking agent and dispersing the rubber in the hydrogenated styrene-based thermoplastic elastomer. ing.
[0005]
[Patent Document 1]
JP-A-11-228708
[0006]
[Problems to be solved by the invention]
The rubber composition described in JP-A-11-228708 has low hardness, excellent abrasion resistance, and can maintain good paper feeding performance for a long period of time. However, in recent years, ink jet printers, laser beam printers, copying machines, and the like as described above have tended to reduce the number of parts for cost reduction, and the burden on rubber rollers has increased, and higher performance has been required. ing.
[0007]
Particularly, in order to make the paper feeding mechanism simpler, a configuration has been developed in which the paper feeding roller idles with the separating member every time one transported object such as paper is fed. Therefore, it is necessary to increase not only the coefficient of friction but also the wear resistance. In particular, high physical strength is required for abrasion by applying a load such as idling, for example, a large tensile strength TB is required.
[0008]
Until now, it was only necessary to have the required abrasion against the abrasion caused by slight deviation from the paper generated when the paper was fed, and the load applied to the roller was low, Physical strength, such as strength, was not as important. In the case of vulcanized rubber, a compound having a somewhat high tensile strength TB can be produced, but the cost of the method for producing a vulcanized rubber increases. Therefore, production of a thermoplastic elastomer composition in a resin step is desired from the viewpoint of good productivity and excellent physical properties.
[0009]
The present invention has been made in view of the above-described problems, and provides an elastomer composition having a low hardness and a very excellent abrasion resistance, and a method for producing the elastomer composition. It is an object of the present invention to provide a paper feed roller that achieves abrasion, and particularly has excellent abrasion resistance during idling.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a rubber component (A) containing at least one of a diene rubber and an EPDM rubber,
A mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin,
A compatibilizer (C) containing at least one of an acid-modified EPDM or an acid-modified hydrogenated styrene-based thermoplastic elastomer;
And a polyamide resin (D),
The compatibilizer (C) is blended in an amount of 2 parts by weight to 40 parts by weight with respect to 100 parts by weight of the mixed composition (B), and the polyamide resin (D) is mixed with the mixed composition (B). B) providing an elastomer composition characterized in that the rubber component (A) is blended in a ratio of 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight, and the rubber component (A) is dynamically crosslinked.
[0011]
As described above, since the polyamide resin is dispersed in the mixture of the diene rubber or the EPDM rubber and the styrene thermoplastic elastomer and the olefin resin by using the compatibilizing agent of the acid-modified product, the hardness is low. Thus, an elastomer composition having high tensile strength and extremely excellent wear resistance can be obtained. Therefore, it is possible to obtain a paper feed roller that achieves low hardness and good wear resistance, and particularly has excellent wear resistance during idling.
[0012]
Specifically, it has been found that slip wear in the paper feed roller has a high correlation with the strength of the material, and in particular, it is necessary to have a high tensile strength (TB). In order to increase the tensile strength, in particular, it is sufficient to increase the resin components such as polypropylene (PP). However, if these resin components are too large, the hardness HS also increases, which is unsuitable as a roller. I will. Therefore, it has been found that, in addition to PP and the like, a polyamide-based resin that is softer and stronger than PP, such as nylon, may be blended as a resin having a high reinforcing property and hardly causing an increase in hardness. Further, by adding the compatibilizer, the diene rubber or the EPDM rubber or the polyamide resin can be finely dispersed uniformly in the matrix resin by dynamic crosslinking, and the dispersibility can be improved. Strength can be increased.
[0013]
The compatibilizer (C) is blended in an amount of 2 to 40 parts by weight based on 100 parts by weight of the mixed composition (B). Thereby, the compatibility of the interface between the rubber phase of the rubber component and the resin phase of the thermoplastic component in the thermoplastic elastomer composition can be efficiently increased.
The reason for setting the above range is that if the amount is less than the above range, the effect of compatibilization does not appear and the strength cannot be improved. On the other hand, if it is more than the above range, the proportion of the compatibilizer in the elastomer composition becomes too large, conversely, the strength is reduced, the hardness is increased, and the cost is increased because the compatibilizer is expensive. To do that. Preferably it is 5 parts by weight or more and 20 parts by weight or less.
[0014]
If the polyamide resin (D) is blended in a proportion of 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the mixed composition (B), a reinforcing effect cannot be obtained if the amount is less than the above range. That's why. On the other hand, if it is more than the above range, the hardness Hs becomes high, and especially when a paper feed roller is used, the coefficient of friction becomes low and it becomes unsuitable for practical use. Preferably it is 10 parts by weight or more and 40 parts by weight or less.
[0015]
The reason for using a diene rubber or EPDM is that dynamic crosslinking is smoothly performed. As the diene rubber, butyl rubber (IIR), butadiene rubber (BR), isoprene rubber (IR), styrene butadiene rubber (SBR), chloroprene rubber (CR), natural rubber (NR), 1,2-polybutadiene, acrylonitrile- Butadiene rubber (NBR) and the like can be used, and one or more kinds can be used, and they may be mixed with EPDM.
[0016]
Hydrogenated styrene-based thermoplastic elastomers are styrene-based thermoplastic elastomers that have been saturated by hydrogenation and have no double bonds, and are compared with TPU (urethane-based thermoplastic elastomer) that has been conventionally used as a matrix. Low hardness, high friction coefficient, and low compression set. In addition, since it does not have a double bond, it does not react with the resin vulcanizing agent and finely disperses the rubber inside the rubber without inhibiting the vulcanization of the rubber. Therefore, an elastomer composition having a lower hardness and a smaller compression set due to the influence of finely dispersed rubber can be produced.
[0017]
The styrene-based thermoplastic elastomer as a raw material of the hydrogenated styrene-based thermoplastic elastomer is a block copolymer composed of a polystyrene phase (S) end block and a rubber (elastomer) intermediate block. (Elastomer) SBS type in which the intermediate block is composed of polybutadiene (B), SIS type in which the rubber (elastomer) intermediate block is composed of polyisoprene (I), SES type in which the rubber (elastomer) intermediate block is composed of polyethylene, rubber (elastomer) intermediate There are a SEPS system in which the block is composed of ethylene / propylene (E / P) and a SEBS system in which the rubber (elastomer) intermediate block is composed of ethylene / butadiene (E / B). Of these, SES, SEPS and SEBS are preferably used.
[0018]
The reason that the olefin resin is used is that the hydrogenated styrene thermoplastic elastomer is compatible with a rubber containing at least one of a diene rubber and an EPDM rubber. As the olefin resin used in the present invention, any commercially available olefin resin can be used.For example, polyethylene and polypropylene are preferable, and in addition, ethylene ethyl acrylate resin, ethylene vinyl acetate resin, ethylene-methacryl resin One or more selected from acid resins and ionomer resins can be used.
[0019]
As the compatibilizer, acid-modified EPDM and acid-modified hydrogenated styrene-based thermoplastic elastomer are preferable. The acid modification is preferably a carboxylic acid modification, and other examples include various acid modifications. Further, a plurality of compatibilizers may be used in combination.
[0020]
As the polyamide resin, a tough resin such as nylon 6, nylon 66, or nylon 12 is preferable, and a resin having a tensile strength TB of 10 MPa or more is more preferable from the viewpoint of the abrasion resistance of the elastomer composition.
[0021]
The rubber component (A) is preferably blended in a proportion of 50 parts by weight or more and 300 parts by weight or less based on 100 parts by weight of the mixed composition (B). If the amount is less than the above range, the content of the dynamically crosslinked rubber becomes too small, and the abrasion resistance is likely to decrease, and the amount of abrasion may increase. On the other hand, if it is more than the above range, the resin content is too small, and it becomes difficult to knead in a dynamic crosslinking step of dispersing and crosslinking rubber in a mixture of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin. is there. Further, the amount is preferably 100 parts by weight or more and 200 parts by weight or less.
[0022]
In the mixed composition (B), the weight ratio of the hydrogenated styrene-based thermoplastic elastomer to the olefin-based resin is (hydrogenated styrene-based thermoplastic elastomer: olefin-based resin) = (100: 5) to (100) : 50) is preferred. Furthermore, (100: 20) to (100: 35) are preferable.
Hydrogenated styrene-based thermoplastic elastomers are superior to olefin-based resins in terms of lowering the hardness of the elastomer composition (improving the frictional force when used as a roller), improving heat resistance, and improving compression set. It is superior to hydrogenated styrene-based thermoplastic elastomers in terms of wear resistance, processability (kneading processability during dynamic crosslinking) and cost of the product. Therefore, in order to compensate for the disadvantages of both, and to take advantage of both, the above weight ratio is used. When the hydrogenated styrene-based thermoplastic elastomer is used in an amount larger than the above weight ratio, the kneading processability of the rubber composition and the abrasion resistance of the roller tend to decrease, and the cost of the roller increases. On the other hand, when the weight ratio of the hydrogenated styrene-based thermoplastic elastomer is smaller than the above-mentioned weight ratio, the heat resistance of the roller is deteriorated (compression set is increased), and the friction coefficient of the roller tends to decrease.
[0023]
The elastomer composition of the present invention preferably has a tensile strength TB described in JIS K6301 of 4.5 MPa or more and 8.5 MPa or less. Thereby, good wear resistance can be obtained. Further, the pressure is preferably not less than 6.0 MPa and not more than 8.0 MPa.
[0024]
The elastomer composition of the present invention preferably has a Shore A hardness HS described in JIS K6301 of 30 or more and 50 or less. This makes it possible to obtain good flexibility when used as a roller or the like. That is, in this range, even if the paper feed roller is pressed against the paper or film with a relatively small pressing force, the paper feed roller is sufficiently deformed, and a large contact area with the paper or film can be obtained. Further, it is preferably 35 or more and 45 or less.
[0025]
Dynamic crosslinking is preferably performed using a resin crosslinking agent. The use of a resin cross-linking agent tends to cause blooming when cross-linked with sulfur, and in particular, a large amount of a vulcanization accelerator must be added together with sulfur to improve the performance such as the strength as a roller. The reason is that the friction coefficient of the roller tends to decrease due to blooming. In addition, when cross-linking is performed with peroxide, poor dispersion of the cross-linking agent occurs during kneading, and the peroxide reacts explosively, and the kneaded material is expelled and processing becomes difficult. The amount of the resin crosslinking agent varies depending on the type of the crosslinking agent, but is preferably from 6 to 18 parts by weight based on 100 parts by weight of the rubber component (A).
[0026]
Examples of the resin vulcanizing agent include an alkylphenol-formaldehyde resin, a melamine-formaldehyde condensate, a triazine-formaldehyde condensate, a sulfurized-p-tert-butylphenol resin, an alkylphenol-sulfide resin, and a hexamethoxymethyl-melamine resin. Can be. Of these, phenols are preferred, and alkylphenol-formaldehyde resins (reactive phenol resins) are particularly preferred. When an alkylphenol-formaldehyde resin is used, good crosslinking is obtained as compared with the case where another resin crosslinking agent is used, so that the strength (abrasion resistance) of the elastomer composition is improved, and when a roller is used. The heat resistance is improved and the compression set is smaller. This is probably because the crosslink density changes. A catalyst such as tin chloride can be added together with the resin crosslinking agent.
[0027]
A crosslinking aid (activator) may be used to appropriately perform a crosslinking reaction. A metal oxide is used as a crosslinking assistant, and zinc oxide and zinc carbonate are particularly preferable.
[0028]
Further, in the elastomer composition of the present invention, a commercially available petroleum-based softener or plasticizer can be used as the softener. For example, petroleum softeners such as aroma type, Teflon (R) type and paraffin type, and plasticizers such as phthalate type, adipate type, sepate type, phosphate type, polyether type and polyester type can be used. Here, the petroleum-based softener refers to those commercially available as a petroleum-based softener and, if the rubber capable of being dynamically vulcanized by the resin crosslinking agent is an oil-extended rubber, contained in the oil-extended rubber. Contains the oil components that are being made.
The softener is blended in an amount of 10 to 200 parts by weight with respect to 100 parts by weight of the rubber component (A). However, if the softener is less than the above range, the effect of adding the softener, that is, It is difficult to obtain the effect of further improving the dispersibility of rubber and the like in the mixture of the hydrogenated styrene-based thermoplastic elastomer and the olefin-based resin at the time of dynamic crosslinking. This is because it is difficult to obtain the effect of improving the strength and wear resistance. In the case of oil-extended rubber, the weight part of rubber means the weight of only the rubber component obtained by subtracting the weight of the oil component from the oil-extended rubber.
[0029]
Further, an anti-aging agent, a filler, and the like can be added to the elastomer composition as needed. Examples of the filler include powders of silica, carbon black, clay, talc, calcium carbonate, dibasic phosphite (DLP), basic magnesium carbonate, and alumina. When a filler is compounded, it is preferable that the filler be compounded in 15% by weight or less of the total weight of the elastomer composition. This is because the compounding of the filler is effective in improving the tensile strength and the tear strength of the elastomer composition, but the flexibility of the elastomer composition to be compounded too much decreases and the friction coefficient of the roller when the roller is used is reduced. This is to show a tendency to decrease.
[0030]
In the present invention, a polymer component (rubber + hydrogenated styrene-based thermoplastic elastomer + olefin resin + resin vulcanizing agent + other) excluding non-polymer components such as process oil, anti-aging agent, filler, etc., with respect to the entire elastomer composition. (Addition resin) is preferably from 40% by weight to 95% by weight, more preferably from 59% by weight to 95% by weight. The content of 40% by weight or more is for improving the strength of the elastomer composition (securing abrasion resistance), and the content of 95% by weight or less ensures the kneading processability and moldability of the elastomer composition. That's why.
[0031]
Further, the present invention provides a composition comprising a mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin, and at least one of acid-modified EPDM or acid-modified hydrogenated styrene-based thermoplastic elastomer. Kneading the agent (C) and the polyamide resin (D), and finely dispersing the polyamide resin (D) in the mixture composition (B) to obtain a thermoplastic composition;
Producing a elastomer composition by dynamically cross-linking the thermoplastic composition and a rubber component (A) containing at least one of a diene rubber or an EPDM rubber. We provide a manufacturing method.
[0032]
Thus, after using the compatibilizer (C) to obtain a thermoplastic composition in which the polyamide resin (D) is dispersed in the mixed composition (B), the thermoplastic composition is obtained. The rubber component (A) is dynamically crosslinked using a crosslinking agent such as a resin crosslinking agent and the rubber component (A), and the rubber component (A) is dispersed in the thermoplastic composition. For this reason, both the rubber component (A) and the polyamide resin (D) are finely dispersed uniformly in the matrix resin phase, and in particular, the tensile strength can be improved, and the wear resistance can be improved.
[0033]
That is, it is possible to prevent poor dispersion that occurs when all the materials are kneaded at the same time and to suppress a decrease in strength accompanying the dispersion. In particular, it is possible to effectively prevent poor dispersion of the polyamide resin that occurs when kneading is performed at the same time. In addition, the dispersion of the fine rubber particles has a smaller particle diameter than that of a kneaded product molded at a time, and the abrasion resistance is further improved. Therefore, the abrasion resistance is excellent, and particularly, the durability against the idling wear is good. That is, an elastomer composition having a large TB can be obtained.
[0034]
In the step of obtaining the thermoplastic composition, the kneading temperature is preferably from 180 ° C to 200 ° C, and the kneading time is preferably from 1 minute to 10 minutes. Kneading and dynamic crosslinking can be performed by a rubber kneading device such as a twin screw extruder, an open roll, a Banbury mixer, and a kneader.
[0035]
It is preferable that a crosslinking agent such as a resin crosslinking agent and a crosslinking auxiliary are blended in the step of producing an elastomer composition by dynamic crosslinking, and the temperature during dynamic crosslinking is preferably 180 ° C to 200 ° C, and the crosslinking time Is preferably 1 minute to 10 minutes. As each compounding material, those described above can be used, and can be appropriately compounded in the above-described compounding amounts and the like.
[0036]
It is preferable that the elastomer composition is extruded from a rubber kneading device and pelletized. The pellets are formed into a sheet by a single screw extruder, and the sheet is sliced or polished to obtain a sheet having a required thickness. Further, the pellets can be formed into a tube by injection molding using an injection molding machine, and the surface of the molded product can be polished and then cut into required dimensions to form a paper feed roller. Note that, instead of the injection molding machine, a single-screw extruder for resin or the like may be used to extrude a tube and cut the same to form a paper feed roller. In addition to the paper feed roller, the present invention can also be used as a member for preventing double feed of paper sheets such as a separation sheet and a separation pad, and a member for various office equipment.
[0037]
Further, the present invention provides a paper feed roller formed by using the elastomer composition of the present invention.
The elastomer composition obtained by kneading and dynamically cross-linking can be formed into a roller shape by extrusion molding, injection molding, or the like to obtain a rubber roller for paper feeding. Therefore, it is possible to increase the tensile strength TB to about 7 to 8 MPa or more while maintaining the low hardness allowed as a roller, which is effective in improving the abrasion resistance against abrasion and reducing the abrasion, and reducing the generation of rubber powder due to repeated use. can do.
[0038]
The paper feed roller of the present invention only needs to have its surface (the surface in contact with a conveyed object such as paper or film) formed of at least the above elastomer composition. Specifically, a tubular molded body made of an elastomer composition is fitted around the outer periphery of a metal core made of metal, ceramics, or the like. If the thickness of the tube-shaped molded body is less than 1 mm, the elasticity is insufficient and the transporting performance tends to be reduced. Therefore, the thickness is 1 mm to 20 mm, preferably 3 mm to 20 mm. Note that an adhesive layer or the like may be provided between the cored bar and the paper feed roller.
[0039]
Further, it is preferable that the surface of the paper feed roller of the present invention is polished. When polishing is performed, the hydrogenated styrene-based thermoplastic elastomer, which is easy to be polished, is cut first, and the rubber is hard to be polished. It is formed. Therefore, the surface of the rubber roller contacts the paper so as to obtain a large gripping force, and the friction coefficient can be greatly increased.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The elastomer composition of the first embodiment comprises 200 parts by weight of oil-extended EPDM (rubber: oil = 100: 100) as a rubber component (A) containing at least one of a diene rubber and an EPDM rubber, and a hydrogenated styrene-based thermoplastic resin. A compatibilizer (C) containing 100 parts by weight of a PP-containing SEPS compound as a mixed composition (B) of an elastomer and an olefin resin, and at least one of an acid-modified EPDM or an acid-modified hydrogenated styrene-based thermoplastic elastomer. ) Contains 5 parts by weight of a carboxylic acid-modified SEBS and 20 parts by weight of a nylon resin as a polyamide resin (D), and is dynamically cross-linked using a resin cross-linking agent composed of a reactive phenolic resin and zinc white as a cross-linking aid. ing.
[0041]
In this elastomer composition, the rubber component (A) and the polyamide resin (D) are finely dispersed uniformly in the mixed composition (B), the tensile strength TB is 7.5 MPa, and the hardness HS is 37.
[0042]
The above elastomer composition is produced by the following method for producing an elastomer composition of the present invention.
[0043]
First, a mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin and a compatibilizer (C) containing at least one of an acid-modified EPDM or an acid-modified hydrogenated styrene-based thermoplastic elastomer. ) And the polyamide resin (D) are kneaded at 200 ° C. by a twin screw extruder at a predetermined blending amount, and the polyamide resin (D) is uniformly finely dispersed in the mixed composition (B). (About 0.1 to 10 μm) to obtain a thermoplastic composition.
[0044]
Thereafter, a phenolic resin crosslinking agent and a crosslinking aid are blended with the thermoplastic component and a rubber component (A) containing at least one of a diene rubber and an EPDM rubber, and the mixture is mixed at 200 ° C. with a twin screw extruder. , And the rubber component is uniformly finely dispersed (about 0.5 to 20 μm) to produce an elastomer composition as a pellet.
[0045]
The pellets are extruded into a tube using a single screw extruder, and a metal core is inserted into the hollow portion to obtain a paper feed roller. As shown in FIG. 1, the paper feed roller 10 is formed by press-fitting a cylindrical roller portion 1 made of the elastomer composition and a shaft core 2 as a core metal into a hollow portion of the roller portion 1. Both are joined and fixed with an adhesive.
[0046]
This makes it possible to obtain an elastomer composition having low hardness, high tensile strength, and extremely excellent wear resistance. Therefore, it is possible to obtain a paper feed roller that achieves low hardness and good wear resistance, and particularly has excellent wear resistance during idling.
[0047]
In addition to the above embodiment, a diene rubber may be used as the rubber component, or EPDM and a diene rubber may be used in combination. As the compatibilizer, acid-modified EPDM may be used, or may be used in combination with an acid-modified styrene-based thermoplastic elastomer. A substantially D-shaped paper feed roller can be formed by press-fitting a substantially D-shaped core material into a hollow portion of a cylindrical roller portion. Note that a knurled groove may be provided on the surface of the paper feed roller.
[0048]
Hereinafter, examples and comparative examples of the paper feed roller of the present invention will be described in detail. Paper feed rollers were manufactured with the respective formulations shown in Table 1 below.
[0049]
[Table 1]

[0050]
・ Rubber component (A); EPDM: Esplen 670F manufactured by Sumitomo Chemical (100% oil exhibition), IIR: Butyl rubber butyl-268 made by Japan Synthetic Rubber (non-oil exhibition)
-Mixed composition (B); SEPS + PP: Kuraray Plastic's SEPS compound CJK1 (with PP) (hydrogenated styrene-based thermoplastic elastomer (SEPS): olefin-based resin (PP)) = (100: 35)
-Compatibilizer (C): Carboxylic acid-modified SEBS: Asahi Kasei Tuftec 1943, Carboxylic acid-modified EPDM: Nippon Synthetic Rubber T7741P
・ Polyamide resin (D); Nylon resin (Nylon 11) PA11
[0051]
A specific method for manufacturing a paper feed roller will be described.
First, the materials are measured, and the mixed composition (B), the compatibilizer (C), and the polyamide resin (D) are mixed in a tumbler at room temperature for 10 minutes, and then biaxially at 200 ° C. A thermoplastic composition was prepared with an extruder (HTM38 manufactured by Ibec), extruded, and pelletized.
[0052]
Next, the materials are weighed, and the thermoplastic component is mixed with 12 parts by weight of a rubber component (A), a resin crosslinking agent (Takkiroll 250-III, manufactured by Taoka Chemical Co., Ltd.), and 5 parts by weight of zinc white, and then tumbled. After mixing at room temperature for 10 minutes, the mixture was dynamically crosslinked at 200 ° C. with a twin-screw extruder (HTM38 manufactured by Ibec) to produce a thermoplastic elastomer composition, which was extruded and pelletized.
[0053]
The pellet was extruded into a tube using a single screw extruder (φ50 extruder manufactured by Kasamatsu Laboratory, 20 rpm, temperature control 190 ° C. to 230 ° C.) to obtain an extruded product having an outer diameter of 22 mm and an inner diameter of 18 mm. This tube-shaped extruded product was cut to a fixed length of 15 mm, and a metal core was inserted into the hollow portion of the tube to form a paper feed roller.
[0054]
(Examples 1 to 7)
As shown in Table 1, the rubber component (A), the mixed composition (B), the compatibilizer (C), and the polyamide resin (D) were blended in prescribed amounts, respectively. As described above, it was manufactured by two steps of a step of obtaining a thermoplastic composition and a step of performing dynamic crosslinking.
[0055]
(Comparative Examples 1-4)
As shown in Table 1, Comparative Example 1 did not use the compatibilizer (C). In Comparative Example 2, a small amount of the compatibilizer (C) was used. In Comparative Example 3, a large amount of the compatibilizer (C) was used. In Comparative Example 4, a large amount of the polyamide resin (D) was used. The manufacturing method was the same as in the example.
[0056]
The paper feed rollers of the above-mentioned Examples and Comparative Examples were evaluated for the reduction in wear and the generation of rubber powder by the methods described below. In addition, the tensile strength TB and the hardness HS were measured. Table 1 shows the evaluation results.
[0057]
(Tensile strength)
The dynamic crosslinked composition was formed into a sheet by injection, and the tensile strength TB was measured according to JIS-K6301.
[0058]
(Wear loss)
The cut product is placed on a round core having a diameter of 20 mm, a load of 300 g is applied thereto, and the bearing is idled at 100 rpm on a separating member (rubber sheet). The state of occurrence was visually checked. The wear loss was determined to be good at 7 mg or less.
[0059]
(hardness)
Hardness HS is Shore A hardness, and was measured based on JIS K6301.
[0060]
As shown in Table 1, Examples 1 to 8 are paper feed rollers manufactured using the elastomer composition of the present invention by the method for manufacturing an elastomer of the present invention. And the loss on abrasion was extremely small, and almost no rubber powder was generated.
[0061]
On the other hand, Comparative Example 1 in which the compatibilizing agent was not blended, and Comparative Example 2 in which the blending amount of the compatibilizing agent was small, had a very low tensile strength, were inferior in abrasion resistance, had a large amount of abrasion loss, A lot of rubber powder was generated. Comparative Example 3 was high in hardness because of a large amount of polyamide resin.
[0062]
【The invention's effect】
As apparent from the above description, according to the present invention, a diene rubber or EPDM rubber, a mixture of a styrene-based thermoplastic elastomer and an olefin-based resin, a polyamide-based resin using an acid-modified compatibilizer. Due to the dispersion, an elastomer composition having low hardness, high tensile strength, and extremely excellent wear resistance can be obtained.
[0063]
Further, according to the production method of the present invention, after obtaining a thermoplastic composition in which the polyamide resin (D) is dispersed in the mixed composition (B), crosslinking of the thermoplastic composition with a resin crosslinking agent or the like is performed. The rubber component (A) is blended with the rubber component (A) to perform dynamic crosslinking, so that both the rubber component (A) and the polyamide resin (D) are uniformly finely dispersed in the matrix resin phase, and particularly the tensile strength. And an elastomer composition having excellent abrasion resistance can be produced with high productivity.
[0064]
As described above, according to the present invention, an elastomer composition having high tensile strength TB and excellent wear resistance can be obtained while having low hardness. Therefore, it is possible to obtain a paper feed roller which realizes low hardness and good wear resistance, and is particularly excellent in wear resistance at the time of high load, which requires high physical strength and which is subjected to idling. Therefore, it can be suitably used for OA equipment such as an ink jet printer, a laser printer, an electrostatic copying machine, and a facsimile machine, and a paper feeding mechanism for transporting paper and film in an automatic teller machine (ATM).
[Brief description of the drawings]
FIG. 1 is a schematic view of a paper feed roller of the present invention.
[Explanation of symbols]
1 Roller part
2 shaft core
10 Paper feed roller

Claims (5)

A rubber component (A) containing at least one of a diene rubber or an EPDM rubber;
A mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin,
A compatibilizer (C) containing at least one of an acid-modified EPDM or an acid-modified hydrogenated styrene-based thermoplastic elastomer;
And a polyamide resin (D),
The compatibilizer (C) is blended in an amount of 2 parts by weight to 40 parts by weight with respect to 100 parts by weight of the mixed composition (B), and the polyamide resin (D) is mixed with the mixed composition (B). E) an elastomer composition which is blended in an amount of 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight, and wherein the rubber component (A) is dynamically crosslinked. The elastomer composition according to claim 1, wherein the rubber component (A) is blended in a proportion of 50 parts by weight or more and 300 parts by weight or less with respect to 100 parts by weight of the mixed composition (B). The elastomer composition according to claim 1 or 2, wherein the tensile strength TB described in JIS K6301 is 4.5 MPa or more and 8.5 MPa or less, and the Shore A hardness HS described in JIS K6301 is 30 or more and 50 or less. A mixed composition (B) of a hydrogenated styrene-based thermoplastic elastomer and an olefin-based resin, and a compatibilizer (C) containing at least one of acid-modified EPDM or acid-modified hydrogenated styrene-based thermoplastic elastomer. Kneading the polyamide-based resin (D) with the polyamide-based resin (D), and finely dispersing the polyamide-based resin (D) in the mixed composition (B) to obtain a thermoplastic composition.
Producing a elastomer composition by dynamically cross-linking the thermoplastic composition and a rubber component (A) containing at least one of a diene rubber or an EPDM rubber. Production method. A paper feed roller formed by using the elastomer composition according to any one of claims 1 to 3.

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