JPH08127675A - Semi-electroconductive rubber composition - Google Patents
Semi-electroconductive rubber compositionInfo
- Publication number
- JPH08127675A JPH08127675A JP26408694A JP26408694A JPH08127675A JP H08127675 A JPH08127675 A JP H08127675A JP 26408694 A JP26408694 A JP 26408694A JP 26408694 A JP26408694 A JP 26408694A JP H08127675 A JPH08127675 A JP H08127675A
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- rubber
- carbon black
- rubber composition
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電子写真装置の導電性
ローラなどの導電性ゴム部品や、静電気対策用のゴム製
品などに利用される半導電性ゴム組成物に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive rubber composition used for conductive rubber parts such as a conductive roller of an electrophotographic apparatus, and a rubber product for preventing static electricity.
【０００２】[0002]
【従来の技術および発明が解決しようとする課題】静電
式複写機、レーザープリンター、ファクシミリなどの種
々の電子写真装置には、導電性ローラを始めとする各種
導電性ゴム部品が使用されている。導電性ゴムは、従来
より、カーボンブラックなどの導電性物質をゴム中に分
散し、体積固有抵抗値を１０〜１０15Ω・cmの範囲にま
で低下させることによって製造されている。2. Description of the Related Art Various electrophotographic rubber parts such as electroconductive rollers are used in various electrophotographic apparatuses such as electrostatic copying machines, laser printers and facsimiles. . Conventionally, conductive rubber has been manufactured by dispersing a conductive substance such as carbon black in rubber to reduce the volume specific resistance value to the range of 10 to 10 15 Ω · cm.
【０００３】上記カーボンブラックは、粒径が小さいも
のほど抵抗値を低下させる効果が大きいために、通常、
粒径が４５ｎｍ以下のものが使用されている。また、か
かる粒径が小さいカーボンブラックを使用した場合、カ
ーボンブラックの添加量が増えるに従ってゴムの抵抗値
が急激に低下するために、体積固有抵抗値が１０4 Ω・
cm以下である導電性ゴムを製造するのは比較的容易であ
る。The above-mentioned carbon black has a larger effect of lowering the resistance value as the particle size is smaller, so that it is usually used.
Those having a particle size of 45 nm or less are used. When carbon black having such a small particle size is used, the resistance value of the rubber sharply decreases as the amount of carbon black added increases, and the volume resistivity value is 10 4 Ω.
It is relatively easy to produce a conductive rubber that is less than or equal to cm.
【０００４】しかし、静電対策用として有用な中抵抗の
導電性ゴム、すなわち体積固有抵抗値が１０5 〜１０10
Ω・cmの領域である半導電性ゴムは、混練時の損失など
によって生じるカーボンブラック含有量のわずかな差
や、射出成形、押出成形などの加工によて生じるゴムの
状態またはカーボンブラックの分散度のわずかな違いな
どによって上記領域内での抵抗値が大きく変動するた
め、抵抗値の再現性が悪く、量産安定性に欠けるという
問題を有している。However, a conductive rubber having a medium resistance useful as a countermeasure against static electricity, that is, a volume specific resistance value of 10 5 to 10 10
The semi-conductive rubber in the Ω · cm range has a slight difference in the carbon black content caused by loss during kneading, the state of rubber caused by processing such as injection molding, extrusion molding, or the dispersion of carbon black. There is a problem that the resistance value in the above-mentioned region largely varies due to a slight difference in the degree, so that the reproducibility of the resistance value is poor and the stability in mass production is lacking.
【０００５】一方、粒径が大きいカーボンブラックは抵
抗値を低下させる効果が小さいことから、かかるカーボ
ンブラックを使用して半導電性ゴムを製造すれば、ゴム
の抵抗値の安定性や再現性を改善することができる。し
かしながら、粒径が大きいカーボンブラックを使用した
のでは、目的の中抵抗領域に達するのに多量のカーボン
ブラックを必要とし、その結果、ゴムの加工性が悪くな
ってしまう。また、ゴムの硬度が高くなるおそれもあ
る。On the other hand, since carbon black having a large particle size has a small effect of lowering the resistance value, if a semiconductive rubber is manufactured using such carbon black, the stability and reproducibility of the resistance value of the rubber will be improved. Can be improved. However, if carbon black having a large particle size is used, a large amount of carbon black is required to reach the target medium resistance region, and as a result, the processability of the rubber deteriorates. In addition, the hardness of the rubber may increase.
【０００６】そこで、本発明の主な目的は、カーボンブ
ラックの含有量がわずかに変化しても中抵抗領域におけ
る体積固有抵抗値の変動が少なく、従ってその領域での
抵抗値の再現性が高く、量産安定性に優れており、しか
も加工性にも優れた半導電性ゴム組成物を提供すること
である。また、本発明の他の目的は、耐オゾン性にも優
れた前記の半導電性ゴム組成物を提供することである。Therefore, the main object of the present invention is that even if the carbon black content slightly changes, the volume resistivity in the medium resistance region does not fluctuate so that the reproducibility of the resistance in that region is high. Another object of the present invention is to provide a semiconductive rubber composition which is excellent in mass production stability and excellent in processability. Another object of the present invention is to provide the above semiconductive rubber composition having excellent ozone resistance.
【０００７】[0007]
【課題を解決するための手段および作用】本発明者ら
は、上記の問題を解決するために鋭意研究を重ねた結
果、ゴム中に、平均粒径が８０ｎｍ以上のカーボンブラ
ックと、平均粒径が３０ｎｍ以下のカーボンブラックと
を４：１〜１：４の重量比で含有するときは、中抵抗領
域における体積固有抵抗値の変化が穏やかで安定した抵
抗値が得られるために、抵抗値の再現性が高く、量産安
定性が優れた半導電性ゴム組成物を容易に得ることがで
きるいう新たな事実を見出し、本発明を完成するに至っ
た。Means and Actions for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that carbon black having an average particle size of 80 nm or more Contains 30 nm or less of carbon black in a weight ratio of 4: 1 to 1: 4, the change in volume resistivity in the medium resistance region is moderate and a stable resistance value is obtained, so that The present invention has been completed by finding a new fact that a semiconductive rubber composition having high reproducibility and excellent mass production stability can be easily obtained.
【０００８】また、前記ゴム中に、主鎖に二重結合を有
しないゴムを１５重量％以上の割合で含有させるとき
は、上記の特性を損なわずに、耐オゾン性にも優れた半
導電性ゴム組成物が得ることができる。以下に、本発明
の半導電性ゴム組成物を詳細に説明する。本発明におけ
るカーボンブラックは、平均粒径が８０ｎｍ以上、好ま
しくは８２〜１１８ｎｍのものと、平均粒径が３０ｎｍ
以下、好ましくは２３〜３０ｎｍのものとからなる。平
均粒径が８０ｎｍ以上のものと３０ｎｍ以下のものとの
重量比は４：１〜１：４になるように配合して使用され
る。When a rubber having no double bond in the main chain is contained in the rubber in a proportion of 15% by weight or more, the semiconductivity excellent in ozone resistance is not impaired. A rubber composition can be obtained. Hereinafter, the semiconductive rubber composition of the present invention will be described in detail. The carbon black in the present invention has an average particle size of 80 nm or more, preferably 82 to 118 nm, and an average particle size of 30 nm.
Hereinafter, it is preferably composed of 23 to 30 nm. The weight ratio of the particles having an average particle size of 80 nm or more and the particles having an average particle size of 30 nm or less is blended to be 4: 1 to 1: 4 and used.
【０００９】カーボンブラックの全配合量は特に限定さ
れないが、通常、原料ゴム１００重量部に対して５〜１
００重量部の範囲内である。カーボンブラックの配合量
が上記の範囲未満では、ゴムの導電性が不十分で、体積
固有抵抗値が１０10Ω・cmより大きな値になるおそれが
あり、上記の範囲より大きい場合は、ゴムの加工性が劣
化したりゴムの硬度が高くなるおそれがある。Although the total amount of carbon black is not particularly limited, it is usually 5 to 1 with respect to 100 parts by weight of the raw rubber.
It is within the range of 00 parts by weight. If the blending amount of carbon black is less than the above range, the conductivity of the rubber is insufficient, and the volume resistivity value may be a value larger than 10 10 Ω · cm. There is a risk that the workability will deteriorate and the hardness of the rubber will increase.
【００１０】本発明に使用可能なカーボンブラックとし
ては、上記平均粒径以外については特に限定されず、フ
ァーネス法、アセチレン法、ランプ法、サーマル法など
の従来公知の方法により製造されたものが使用可能であ
り、とくにカーボンブラックの粒度分布の小さいものが
好ましい。本発明に使用可能な原料ゴムとしては、従来
公知のものが使用可能であり、例えば天然ゴム（Ｎ
Ｒ）、イソプレンゴム（ＩＲ）、スチレンゴム（ＳＢ
Ｒ）、ブタジエンゴム（ＢＲ）、クロロプレンゴム（Ｃ
Ｒ）、ブチルゴム（ＩＩＲ）、ハロゲン化ブチルゴム、
ポリイソブチレン、ニトリルゴム（ＮＢＲ）、クロロス
ルホン化ポリエチレンゴム（ＣＳＭ）、クロロスルホン
化ポリエチレンゴム（ＣＳＭ）、アクリルゴム（ＡＣ
Ｍ，ＡＮＭ）、ウレタンゴム（Ｕ）、シリコーンゴム
（Ｓｉ）などが挙げられ、これらの２種以上の原料ゴム
を混合して用いることもできる。また、オゾン雰囲気下
に曝されるおそれのある電子写真複写装置などで使用す
る場合は、ゴムの劣化を防止するために、耐オゾン性が
優れた原料ゴムを使用するのが好ましい。The carbon black that can be used in the present invention is not particularly limited except for the above average particle size, and carbon black produced by a conventionally known method such as a furnace method, an acetylene method, a lamp method or a thermal method is used. It is possible, and carbon black having a small particle size distribution is particularly preferable. As the raw material rubber that can be used in the present invention, conventionally known ones can be used. For example, natural rubber (N
R), isoprene rubber (IR), styrene rubber (SB
R), butadiene rubber (BR), chloroprene rubber (C
R), butyl rubber (IIR), halogenated butyl rubber,
Polyisobutylene, nitrile rubber (NBR), chlorosulfonated polyethylene rubber (CSM), chlorosulfonated polyethylene rubber (CSM), acrylic rubber (AC
M, ANM), urethane rubber (U), silicone rubber (Si) and the like, and two or more kinds of these raw material rubbers can be mixed and used. Further, when used in an electrophotographic copying machine or the like that may be exposed to an ozone atmosphere, it is preferable to use a raw material rubber having excellent ozone resistance in order to prevent deterioration of the rubber.
【００１１】上記耐オゾン性に優れた原料ゴムとして
は、主鎖に二重結合を有しないゴムが挙げられ、例えば
シリコーンゴム、ウレタンゴム、エチレン−プロピレン
ゴム（ＥＰＭ）、エチレン−プロピレン−ジエン共重合
ゴム（ＥＰＤＭ）、アクリルゴム、ウレタンゴムフッ素
ゴム、ブチルゴム（ＩＩＲ）、ハロゲン化ブチルゴム、
クロロプレンゴム（ＣＲ）、クロロスルホン化ポリエチ
レンゴム（ＣＳＭ）、エピクロルヒドリン−エチレンオ
キシド共重合ゴム（ＣＨＣ）、エピクロルヒドリン単独
重合ゴム（ＣＨＲ）、ニトリルゴム（ＮＢＲ）の水素化
物、塩素化ポリエチレン、ポリ塩化ビニル（ＰＶＣ）−
ＮＢＲブレンド物などが挙げられる。これらのうち、ゴ
ムの加工性が良好で低価格であるエチレン−プロピレン
−ジエン共重合ゴム（以下、ＥＰＤＭという）を用いる
のが好ましい。Examples of the above-mentioned raw rubber having excellent ozone resistance include rubbers having no double bond in the main chain. For example, silicone rubber, urethane rubber, ethylene-propylene rubber (EPM), ethylene-propylene-diene Polymerized rubber (EPDM), acrylic rubber, urethane rubber fluororubber, butyl rubber (IIR), halogenated butyl rubber,
Chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), epichlorohydrin-ethylene oxide copolymer rubber (CHC), epichlorohydrin homopolymer rubber (CHR), hydride of nitrile rubber (NBR), chlorinated polyethylene, polyvinyl chloride ( PVC)-
Examples include NBR blends. Among these, it is preferable to use ethylene-propylene-diene copolymer rubber (hereinafter referred to as EPDM), which has good rubber processability and is inexpensive.
【００１２】耐オゾン性に優れたゴム組成物を得る場合
は、原料ゴム１００重量部中に上記耐オゾン性に優れた
原料ゴムを１５重量部以上、好ましくは３０重量部以上
配合する。この割合が１５重量部未満の場合は十分な耐
オゾン性を得ることができない。尚、ここでいう耐オゾ
ン性を有するゴム組成物とは、オゾン濃度５０ｐｐｈｍ
の雰囲気下、４０℃で９６時間放置した後、１０％伸長
させても亀裂が生じないものをいう。To obtain a rubber composition having excellent ozone resistance, 15 parts by weight or more, preferably 30 parts by weight or more of the raw material rubber having excellent ozone resistance is mixed with 100 parts by weight of the raw material rubber. If this ratio is less than 15 parts by weight, sufficient ozone resistance cannot be obtained. In addition, the rubber composition having ozone resistance here means an ozone concentration of 50 pphm.
After being left at 40 ° C. for 96 hours in the atmosphere of 1), it does not cause cracks even if it is elongated by 10%.
【００１３】本発明のゴム組成物には、上記各成分のほ
かに、例えば加硫剤、加硫促進剤、老化防止剤、補強
剤、充填剤などの従来公知の種々の添加剤を所定の割合
で添加することも可能である。本発明のゴム組成物は、
例えば以下の方法で製造される。まず、天然ゴムなどの
原料ゴムに、主鎖に二重結合を有しない耐オゾン性に優
れたＥＰＤＭなどの原料ゴムを必要に応じて混合し、平
均粒径が８０ｎｍ以上のカーボンブラックと平均粒径が
３０ｎｍ以下のカーボンブラックとを、所望の体積固有
抵抗値に応じた配合比および配合量で配合する。In the rubber composition of the present invention, in addition to the above components, various conventionally known additives such as a vulcanizing agent, a vulcanization accelerator, an antiaging agent, a reinforcing agent, and a filler are predetermined. It is also possible to add in a ratio. The rubber composition of the present invention is
For example, it is manufactured by the following method. First, a raw material rubber such as natural rubber or the like is mixed with a raw material rubber such as EPDM having no double bond in the main chain and excellent in ozone resistance, if necessary, and carbon black having an average particle size of 80 nm or more Carbon black having a diameter of 30 nm or less is blended at a blending ratio and a blending amount according to a desired volume resistivity value.
【００１４】次いで、加硫剤、加硫促進剤、老化防止
剤、補強剤、充填剤などの各種添加剤を所定の割合で配
合し、素練り、成形、加硫などの操作を施す。Next, various additives such as a vulcanizing agent, a vulcanization accelerator, an antiaging agent, a reinforcing agent, and a filler are mixed at a predetermined ratio, and operations such as mastication, molding and vulcanization are performed.
【００１５】[0015]
【実施例】次に、実施例と比較例を挙げて本発明の半導
電性ゴム組成物を説明する。半導電性ゴム組成物の作製 実施例１〜１０ 原料ゴムとして天然ゴム（ＳＭＲ５ＣＶ）およびＥＰＤ
Ｍ（住友化学工業（株）製のエスプレン５０１Ａ）を用
い、これらを下記の表１に示す割合で混合し、ロール機
を用いて素練りを行った。EXAMPLES Next, the semiconductive rubber composition of the present invention will be described with reference to Examples and Comparative Examples. Preparation Examples of Semiconductive Rubber Composition Examples 1 to 10 Natural rubber (SMR5CV) and EPD as raw rubbers
M (Esprene 501A manufactured by Sumitomo Chemical Co., Ltd.) was mixed in the proportions shown in Table 1 below, and masticated using a roll machine.
【００１６】次いで、カーボンブラックと、下記の各添
加剤とを配合し、ロール機を用いて溶融・混練を行い、
半導電性ゴム組成物を作製した。 *1 大内新興化学社製のＭＢＴ １．０重量部、ＴＭＴ
Ｄ １．５重量部およびＢＺ ０．５重量部 カーボンブラックは、平均粒径が８２ｎｍまたは１１８
ｎｍのものと、平均粒径が２３ｎｍまたは３０ｎｍのも
のとを組み合わせて使用した。その配合比は、下記の表
１に示すとおりである。Next, carbon black and the following additives are blended and melted and kneaded by using a roll machine,
A semiconductive rubber composition was prepared. * 1 1.0 part by weight of MBT made by Ouchi Shinko Chemical Co., Ltd., TMT
D 1.5 parts by weight and BZ 0.5 parts by weight Carbon black has an average particle size of 82 nm or 118.
and those having an average particle size of 23 nm or 30 nm were used in combination. The compounding ratio is as shown in Table 1 below.
【００１７】尚、カーボンブラックの配合量は、原料ゴ
ム１００重量部に対して０〜１００重量部の範囲内で調
整し、数種の配合例を各実施例毎に作製した。The blending amount of carbon black was adjusted within the range of 0 to 100 parts by weight with respect to 100 parts by weight of the raw rubber, and several types of blending examples were prepared for each example.
【００１８】[0018]
【表１】 [Table 1]
【００１９】比較例１〜１０ 使用した原料ゴムが、天然ゴム８５重量部およびＥＰＤ
Ｍ１５重量部であり、使用したカーボンブラックが異な
るほかは、実施例１〜１０と同様にして半導電性ゴム組
成物を作製した。カーボンブラックは、平均粒径が２３
ｎｍ、３０ｎｍ、６２ｎｍまたは８２ｎｍのカーボンブ
ラックを単独で、またはこのうちの２種類を組み合わせ
て用いた。２種類のカーボンブラックを組み合わせた場
合の配合比は、下記の表２に示すとおりである。Comparative Examples 1 to 10 The raw material rubber used was 85 parts by weight of natural rubber and EPD.
M 15 parts by weight, and a semiconductive rubber composition was prepared in the same manner as in Examples 1 to 10 except that the carbon black used was different. Carbon black has an average particle size of 23
nm, 30 nm, 62 nm or 82 nm carbon black was used alone or in combination of two types. The compounding ratio when two kinds of carbon black are combined is as shown in Table 2 below.
【００２０】尚、カーボンブラックの配合量は、原料ゴ
ム１００重量部に対して０〜１００重量部の範囲内で調
整し、数種の配合例を各比較例毎に作製した。The blending amount of carbon black was adjusted within the range of 0 to 100 parts by weight relative to 100 parts by weight of the raw rubber, and several types of blending examples were prepared for each comparative example.
【００２１】[0021]
【表２】 [Table 2]
【００２２】各実施例および各比較例で使用したカーボ
ンブラックの製造者、商品名および米国材料試験協会に
よる規格番号（ＡＳＴＭ No.）を表３に示す。Table 3 shows the manufacturer, trade name, and standard number (ASTM No.) of the carbon black used in each example and each comparative example by the American Society for Testing and Materials.
【００２３】[0023]
【表３】 [Table 3]
【００２４】体積固有抵抗値の測定 上記実施例および比較例で得られた半導電性ゴム組成物
を、それぞれ１５０℃で１０分間プレス加硫し、縦１０
ｃｍ、横１０ｃｍ、厚さ０．２ｃｍのゴム板に成型した
ものを試験片として使用した。測定は、温度２３．５
℃、湿度５５％ＲＨの条件下で、アドバンテストコーポ
レーション社製のデジタル超高抵抗微小電流計Ｒ−８３
４０／８３４０Ａを用いて行った。 Measurement of volume resistivity value The semiconductive rubber compositions obtained in the above-mentioned Examples and Comparative Examples were press-vulcanized at 150 ° C. for 10 minutes, respectively, and longitudinally 10
A rubber plate having a size of 10 cm, a width of 10 cm, and a thickness of 0.2 cm was used as a test piece. The temperature is 23.5.
Digital ultra high resistance micro ammeter R-83 manufactured by Advantest Corporation under the conditions of ℃ and 55% RH.
40 / 8340A.
【００２５】実施例１〜１０および比較例５〜１０の結
果を図１に、比較例１〜５の結果を図２にそれぞれ示
す。Δ（カーボンブラック）量の測定 図１および図２のグラフから、体積固有抵抗値が１０5
Ω・cmのときと１０10Ω・cmのときの各カーボンブラッ
クの配合量を求め、それらの配合量の差〔Δ（カーボン
ブラック）量〕を計算した。この値が大きいほどカーボ
ンブラックの添加量の増大に対する抵抗値の変化が小さ
いことを示す。また、本実施例および比較例におけるカ
ーボンブラックの配合量の範囲内で体積固有抵抗値が１
０5 Ω・cmに達しなかったものについては、測定不可と
した。中抵抗領域における加工性の評価 各実施例および各比較例について、ゴムの混練から押出
成形、加硫プレスによるゴム板の作製までの各工程での
加工性の良否を評価した。加工性の評価は、各実施例お
よび各比較例毎にすべての配合例について総合的に行
い、加工性が良好なものを〇、加工性に劣っていて実用
性がないものを×とした。耐オゾン性の評価 各実施例および各比較例において、上記体積固有抵抗値
の測定に用いたものと同様の試験片を用い、オゾン濃度
５０ｐｐｈｍの雰囲気下、４０℃で９６時間放置した
後、１０％伸長させて亀裂の有無を観察した。耐オゾン
性の評価は、各実施例および各比較例毎にすべての配合
例について行い、亀裂が発生しなかったものを〇（耐オ
ゾン性が良好）、発生したものを×（耐オゾン性が不
良）として評価した。The results of Examples 1 to 10 and Comparative Examples 5 to 10 are shown in FIG. 1, and the results of Comparative Examples 1 to 5 are shown in FIG. Measurement of Δ (carbon black) amount From the graphs of FIGS. 1 and 2, the volume resistivity value is 10 5
The blending amount of each carbon black at Ω · cm and at 10 10 Ω · cm was obtained, and the difference between the blending amounts [Δ (carbon black) amount] was calculated. The larger this value is, the smaller the change in the resistance value with the increase in the addition amount of carbon black is. In addition, the volume resistivity value was 1 within the range of the blending amount of carbon black in the present example and the comparative example.
Those that did not reach 0 5 Ω · cm were not determined to be measurable. Evaluation of Workability in Medium Resistance Region For each of Examples and Comparative Examples, the quality of workability in each step from kneading of rubber to extrusion molding and production of a rubber plate by a vulcanizing press was evaluated. The workability was evaluated comprehensively for all of the compounding examples in each of the examples and comparative examples. Good workability was rated as ◯, and poor workability and impracticality was rated as x. Evaluation of ozone resistance In each Example and each Comparative Example, a test piece similar to that used for the measurement of the volume resistivity value was used and left at 40 ° C. for 96 hours in an atmosphere with an ozone concentration of 50 pphm, and then 10 %, And the presence or absence of cracks was observed. The ozone resistance was evaluated for all of the compounding examples in each of the examples and the comparative examples. When no cracks were generated, ◯ (ozone resistance was good), and when cracks were generated, x (ozone resistance was It was evaluated as (defective).
【００２６】上記のΔ（カーボンブラック）量、中抵抗
領域における加工性および耐オゾン性についての結果を
表４に示す。Table 4 shows the results of the above Δ (carbon black) amount, workability in the medium resistance region and ozone resistance.
【００２７】[0027]
【表４】 [Table 4]
【００２８】上記実施例１〜１０は、平均粒径が８０ｎ
ｍ以上のカーボンブラックと平均粒径が３０ｎｍ以下の
カーボンブラックとを、重量比が４：１〜１：４の範囲
で配合しており、図１およびΔ（カーボンブラック）量
の値より明らかなように、中抵抗領域での抵抗値の変化
が緩やかである。また、かかる領域における加工性も良
好である。In Examples 1 to 10 above, the average particle size was 80 n.
The carbon black of m or more and the carbon black having an average particle diameter of 30 nm or less are blended in a weight ratio of 4: 1 to 1: 4, which is clear from FIG. 1 and the value of Δ (carbon black) amount. As described above, the change in the resistance value in the medium resistance region is gradual. Further, the workability in this region is also good.
【００２９】一方、平均粒径が８０ｎｍ以上のカーボン
ブラックを含有していない比較例１〜３、５〜６および
８のゴム組成物や、平均粒径が３０ｎｍ以下のカーボン
ブラックを多量に添加している比較例９は、中抵抗領域
での抵抗値が急激に変化している。このために、わずか
な量のカーボンブラックの添加によって体積固有抵抗値
が大きく変動し、抵抗値の再現性が悪くなり、量産安定
性にも欠ける。On the other hand, a large amount of the rubber compositions of Comparative Examples 1-3, 5-6 and 8 containing no carbon black having an average particle diameter of 80 nm or more and carbon black having an average particle diameter of 30 nm or less were added. In Comparative Example 9 in which the resistance value changes, the resistance value in the medium resistance region changes abruptly. For this reason, the addition of a small amount of carbon black causes a large change in the volume resistivity value, which deteriorates the reproducibility of the resistance value and lacks mass production stability.
【００３０】これとは逆に、平均粒径が８０ｎｍ以上の
カーボンブラックを多量に添加している比較例１０や、
平均粒径が３０ｎｍ以下のカーボンブラックを含有して
いない比較例４および７のゴム組成物は、中抵抗領域の
抵抗値に達するためにカーボンブラックを多量に必要と
し、ゴムの加工性が悪くなる。また、表４から明らかな
ように、耐オゾン性に優れたゴムであるＥＰＤＭが原料
ゴム中に１５重量％以上含まれている実施例１〜８およ
び比較例１〜１０のゴム組成物は、耐オゾン性が良好で
ある。一方、ＥＰＤＭの配合量が１５重量％以下である
実施例９および１０のゴム組成物は、耐オゾン性が良好
でない。On the contrary, Comparative Example 10 in which a large amount of carbon black having an average particle size of 80 nm or more is added,
The rubber compositions of Comparative Examples 4 and 7 which do not contain carbon black having an average particle diameter of 30 nm or less require a large amount of carbon black to reach the resistance value in the medium resistance region, resulting in poor rubber processability. . Further, as is clear from Table 4, the rubber compositions of Examples 1 to 8 and Comparative Examples 1 to 10 in which EPDM, which is a rubber excellent in ozone resistance, is contained in the raw rubber in an amount of 15% by weight or more, Good ozone resistance. On the other hand, the rubber compositions of Examples 9 and 10 in which the compounding amount of EPDM is 15% by weight or less are not good in ozone resistance.
【００３１】[0031]
【発明の効果】本発明のゴム組成物は、粒径が大きいカ
ーボンブラックと粒径が小さいカーボンブラックとを所
定の割合で配合しているために、中抵抗領域における抵
抗値の変化が緩やかであり、安定した体積固有抵抗値が
得られる。このため、抵抗値の再現性が優れ、量産安定
性に優れている。Since the rubber composition of the present invention contains carbon black having a large particle diameter and carbon black having a small particle diameter in a predetermined ratio, the change in the resistance value in the medium resistance region is moderate. Yes, a stable volume resistivity value can be obtained. Therefore, the reproducibility of the resistance value is excellent and the mass production stability is excellent.
【００３２】さらに、主鎖に二重結合を有しないゴムを
原料ゴム中に所定量配合した場合は、耐オゾン性をも有
する半導電性ゴム組成物を製造することができる。かか
る本発明の半導電性ゴム組成物は、電子写真複写装置用
の導電性ローラーなどの各種導電性ゴム部品や、静電気
対策用のゴム製品などの用途に好適である。Further, when a predetermined amount of rubber having no double bond in the main chain is blended in the raw rubber, a semiconductive rubber composition having ozone resistance can be produced. The semiconductive rubber composition of the present invention is suitable for various conductive rubber parts such as a conductive roller for electrophotographic copying machines, and rubber products for preventing static electricity.
【図１】実施例１〜１０および比較例５〜１０で得られ
たゴム組成物におけるカーボンブラックの配合量とゴム
の体積固有抵抗値との関係を示すグラフである。FIG. 1 is a graph showing the relationship between the compounding amount of carbon black and the volume resistivity of rubber in the rubber compositions obtained in Examples 1 to 10 and Comparative Examples 5 to 10.
【図２】比較例１〜４で得られたゴム組成物におけるカ
ーボンブラックの配合量とゴムの体積固有抵抗値との関
係を示すグラフである。FIG. 2 is a graph showing the relationship between the compounding amount of carbon black and the volume resistivity value of rubber in the rubber compositions obtained in Comparative Examples 1 to 4.
Claims (3)
ボンブラックと、平均粒径が３０ｎｍ以下のカーボンブ
ラックとを４：１〜１：４の重量比で含有することを特
徴とする半導電性ゴム組成物。1. A rubber containing carbon black having an average particle size of 80 nm or more and carbon black having an average particle size of 30 nm or less in a weight ratio of 4: 1 to 1: 4. Conductive rubber composition.
ゴムを１５重量％以上の割合で含有する請求項１記載の
半導電性ゴム組成物。2. The semiconductive rubber composition according to claim 1, wherein the rubber contains a rubber having no double bond in the main chain in a proportion of 15% by weight or more.
−プロピレン−ジエン共重合ゴムである請求項２記載の
半導電性ゴム組成物。3. The semiconductive rubber composition according to claim 2, wherein the rubber having no double bond in the main chain is an ethylene-propylene-diene copolymer rubber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26408694A JP2885651B2 (en) | 1994-10-27 | 1994-10-27 | Semiconductive rubber composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26408694A JP2885651B2 (en) | 1994-10-27 | 1994-10-27 | Semiconductive rubber composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08127675A true JPH08127675A (en) | 1996-05-21 |
| JP2885651B2 JP2885651B2 (en) | 1999-04-26 |
Family
ID=17398325
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26408694A Expired - Fee Related JP2885651B2 (en) | 1994-10-27 | 1994-10-27 | Semiconductive rubber composition |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2885651B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100844741B1 (en) * | 2007-05-08 | 2008-07-07 | 현대자동차주식회사 | Rubber composition for automobile torsional damper |
| WO2008133221A1 (en) * | 2007-04-20 | 2008-11-06 | Canon Kabushiki Kaisha | Development roller, process for production of development roller, process cartridge, and image forming apparatus |
| JP2016128541A (en) * | 2015-01-09 | 2016-07-14 | 株式会社リコー | Semiconductive resin composition, member for electrophotography, and image forming apparatus |
-
1994
- 1994-10-27 JP JP26408694A patent/JP2885651B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008133221A1 (en) * | 2007-04-20 | 2008-11-06 | Canon Kabushiki Kaisha | Development roller, process for production of development roller, process cartridge, and image forming apparatus |
| US7580660B2 (en) | 2007-04-20 | 2009-08-25 | Canon Kabushiki Kaisha | Developing roller, process for producing developing roller, process cartridge and image forming apparatus |
| KR100844741B1 (en) * | 2007-05-08 | 2008-07-07 | 현대자동차주식회사 | Rubber composition for automobile torsional damper |
| JP2016128541A (en) * | 2015-01-09 | 2016-07-14 | 株式会社リコー | Semiconductive resin composition, member for electrophotography, and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2885651B2 (en) | 1999-04-26 |
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