JPH10221930A - Sponge rubber composition and production of sponge rubber roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sponge rubber compsn. having a relatively small cell diameter of a specific value or below in an average cell diameter even in a free foaming method using a cross head by incorporating ethylene-propylene copolymer rubber (EPDM) and liquid ethylene-propylene copolymer into this compsn. SOLUTION: The liquid ethylene-propylene copolymer is incorporated into the EPDM which is base rubber. While the compounding ratio of the EPDM and the ethylene-propylene copolymer is properly selective according to the kinds of the respective components, the applications of the desired sponge rubber, etc., the compsn. prepd. by replacing 3 to 20 pts.wt. of 100 pts.wt. EPDM with the liquid ethylene-propylene copolymer is preferable. The liquid ethylene- propylene copolymer is incorporated into the EPDM in such a manner, by which the relatively fine cell diameter of <=250μm in the average cell diameter is formed and the variation in the cell diameter is ameliorated even when the free foaming method is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sponge rubber composition and a method for producing a roller using the same.
A sponge rubber composition for a roller suitable for a transfer roller or a charging roller installed around a photoreceptor in an image forming apparatus such as an electronic copying machine or a laser beam printer (hereinafter referred to as LBP) and a roller using the same. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, in OA equipment such as an electronic copying machine and an LBP, charging and transfer in an image forming apparatus have been changed from a conventional charger system using a wire corotron to a roller system in order to reduce ozone. A transfer roller that transfers an image on the photoconductor to a transfer material that comes into contact with the body and passes through a contact portion with the photoconductor, and a charging roller that contacts the photoconductor and charges the photoconductor are being adopted. Such a roller needs to have low hardness in order to obtain a high-quality image, and sponge rubber is generally applied. Methods for manufacturing such sponge type rollers are roughly classified into two types: a free foaming method and an in-mold foaming method. The free foaming method is further roughly classified into two types. A method of manufacturing a roller by forming a rubber composition containing a foaming agent around a core metal, and then heating and foaming the rubber composition. There is a method in which the composition is extruded into a hose shape by an extruder, heated and foamed to form a sponge rubber hose, and then a core is inserted to produce a roller. Further, the in-mold foaming method is a method of forming a rubber composition containing a foaming agent around a cored bar, then installing the rubber composition in a mold cavity, and heating and foaming in the mold to produce a roller. In the transfer roller and the charging roller, a fine cell (bubble) diameter is required in order to stabilize the electric resistance. It has become mainstream.

[0003]

However, in the in-mold foaming method, 50 to 90% of the volume of the mold cavity is usually used.
Rubber is charged to a predetermined volume% within the range of about, but there is a problem that the sponge hardness after foaming varies because of difficulty in adjusting the volume to the predetermined volume%. Further, when charging the unvulcanized rubber material into the mold, it is difficult to provide the rubber material such that the distribution amount is uniform over the entire circumference of the cored bar. For this reason, an uneven force acts on the metal core via the rubber material at the time of pressurization by the metal mold, the metal core bends, and therefore, when the product is removed from the metal mold after vulcanization,
Since the core metal bends again, the dimensional accuracy of the resulting product is poor. Also, for the pressure vulcanization,
It is necessary to increase the amount of the unvulcanized rubber material to be charged into the mold, but as a result, burrs are easily generated, and finishing (polishing) is troublesome. In addition, although the free foaming method allows foaming without being restricted by the volume in the cavity, it has the disadvantage that the cell diameter of the sponge is large and the cell diameter varies widely. Although this cell diameter is reduced when using an extruder with a vent (vacuum evacuation) at the time of extrusion, in particular, among the methods for forming an unvulcanized rubber layer on the outer periphery of a core metal, a crosshead is used at the time of extrusion. In the method of simultaneously extruding the rubber and extruding the core metal to form an unvulcanized rubber layer around the core metal, the load at the time of extrusion is large, so that the Mooney viscosity of the rubber compound is 20 (measurement condition: ML1 + 4 It is necessary to use a low-viscosity composition of about 100 ° C. or less, and when such a composition is used, there is a problem that even if an extruder with a vent is used, the variation in cell diameter is not improved. The present invention has been made in view of these points, and has as its object to provide a sponge rubber having a relatively fine cell diameter of 250 μm or less even in a free foaming method using a crosshead.

[0004]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have conducted intensive studies and found that ethylene-propylene copolymer rubber (hereinafter referred to as "EPDM") is in liquid ethylene-propylene copolymer. It has been found that the sponge rubber made of EPDM having a relatively fine cell diameter can be obtained even by the free foaming method using a crosshead by adding the coalescing, and the present invention has been completed. That is, the characteristics of the sponge rubber composition of the present invention include:
The point is that a liquid ethylene-propylene copolymer is contained in EPDM as a base rubber. In the sponge rubber composition of the present invention, the mixing ratio of EPDM and ethylene-propylene copolymer can be appropriately selected by those skilled in the art according to the type of each component, the intended use of the sponge rubber, and the like. But usually 3% of 100 parts by weight of EPDM
It is preferable that about 20 parts by weight is replaced with a liquid ethylene-propylene copolymer.

[0005] The sponge rubber composition of the present invention may optionally contain, as other components, fillers, softeners, vulcanizing agents, foaming agents, and the like, which are well known in the art. Further, a feature of the method for producing a sponge rubber roller of the present invention is that at least the outer periphery of the cored bar is formed by heating and vulcanizing and foaming the sponge rubber composition. The production method of the present invention can be carried out by any of the conventionally known free foaming method and in-mold foaming method. According to the sponge rubber composition of the present invention, by adding a liquid ethylene-propylene copolymer to EPDM, a relatively fine average cell diameter of 250 μm or less even when the free foaming method is used. The cell diameter is formed, and the variation in the cell diameter can be improved.

[0006]

Embodiments of the present invention will be described below. Ethylene-propylene copolymer rubber used as the base rubber of the sponge rubber composition of the present invention,
An ethylene-propylene-non-conjugated diene terpolymer (EPDM) in which a non-conjugated diene has been introduced as a third component having an unsaturated bond in an ethylene-propylene copolymer, and the third component is dicyclohexane Pentadiene, dicyclooctadiene, 5-methylene-2-norbornene, 5
-Ethylidene-2-norbornene, 1,4-hexadiene and the like.

The specific grade of this EPDM is Mitsui EPT 0045, 1035, 1045, 10
60, 1070, 1071, 3012P, 3045, 3
042E, 3062E, 3070, 3072E, 309
0E, 8075E, 3091, 3095, 4010, 4
211, 4045, 4070, 4095 (the above are trade names of Mitsui Petrochemical Industries, Ltd.), Esplene 201,
301, 305, 400, 501A, 502, 505
505A, 512F, 514F, 522, 524, 53
2,552,553,567,582F, 586,60
0F, 601F, 606, 670F, 671F, 67
3, 5214, 5754, 6506S, 6182F (trade names of Sumitomo Chemical Co., Ltd.), JSR EP9
12P, EP01P, EP02P, EP941P, EP
961SP, EP07P, EP57P, EP181S
P, EP11, EP43, EP93, EP24, EP2
7, EP21, EP132, EP22, EP25, EP
33, EP35, EP37C / F, EP65, EP5
1, EP57C / F, EP75F, EP86, EP9
6, EP98, EP103AF, EP106EF, EP
107F, EP801E, EP001DE (all trade names, manufactured by Nippon Synthetic Rubber Co., Ltd.), Kertan 520, 72
0,820,312,512,712,812,31
4,514,714,378,578,778,450
2,4802,4778,4703,4903,563
1A, 512 × 50, 708 × 15, 509 × 100
(The above is the product name of Idemitsu DSM Corporation), NO
RDEL 1040, 1070, 1145, 1320,
1440, 1470, 1660, 2522, 2722 /
P, 2744 / P, 2760 / P (Dupon (D
uPont) (US) (brand name), Epsyn
40-A, 70-A, 55, 2308, 2506, 45
06,4906,5206,5508,5805,75
06, E801, N557, N597, N997, P5
57, P558, P597, MDE239, MDE24
8 (above, Copolymer Rubber and Chemical Corporation)
& Chemical Corporation) (US) (brand name), POLYSAR 227, 30
6,345,585,487XP, 865,965,5
465, 5672X, 5875, 6463 (these are referred to as Polysar R Corporation).
Uber Corporation) (trade name, manufactured by U.S.A.).

In the present invention, these EPDs
M may be used alone, or two or more EPDMs may be appropriately blended and used for the purpose of adjusting Mooney viscosity, propylene content, oil-extended oil amount, vulcanization rate, or the like,
Other types of rubber such as SBR and NBR may be blended and used. The liquid ethylene-propylene copolymer contained in the sponge rubber composition of the present invention is an essential component of the present invention. This is a viscous low molecular weight (about 3,000
Ethylene-propylene copolymer (hereinafter referred to as "liquid EPT") comprising only ethylene and propylene and having no unsaturated bond in the molecule. Ethylene-propylene-conjugated diene 3 in which a non-conjugated diene is introduced as a third component having an unsaturated bond in a propylene copolymer
There is an original copolymer (hereinafter, referred to as “liquid EPDM”).

[0009] As the liquid EPT, TRILENECP
80P, TRILENECP80 (above, Uniroyal Chemical Company, Inc.
Chemical Company Inc. ) (U.S.A.). As the liquid EPDM, it is assumed that the third component is dicyclopentadiene, and TRILENE56, TRILENE65 (above,
Uniroyal Chemical Company, Inc. (Uni
royal Chemical Company In
c. ) (U.S.A.) and the like, and assuming that the third component is 5-ethylidene-2-norbornene,
Uniroyal Chemical Company, Inc. (Uni
royal Chemical Company In
c. ) (U.S.A.), and the like, but in the present invention, the use of a liquid EPDM having a third component is preferred.

For vulcanization (crosslinking) of the sponge rubber composition of the present invention, an ordinary sulfur vulcanization system can be applied. The sulfur used for the sulfur vulcanization is added in an amount of about 0 to 5 parts by weight based on 100 parts by weight of the base rubber. As the sulfur, fine powder obtained by pulverizing the recovered sulfur is used.
200 mesh, 300 mesh, and 325 mesh (these are the trade names of Tsurumi Chemical Industry Co., Ltd.) are exemplified. In addition, surface-treated sulfur having improved dispersibility and the like is also used as appropriate, including Sulfax A, 200S, MC, P
S, PMC (Trade name of Tsurumi Chemical Industry Co., Ltd.) and the like are exemplified. In order to avoid bloom from unvulcanized rubber, insoluble sulfur is used, such as Seimi Sulfur (trade name, manufactured by Nippon Kaizoku Kogyo Co., Ltd.), Sunfel,
An example is Sunfel 90 (trade name, manufactured by Sanshin Chemical Industry Co., Ltd.).

In particular, when low compression set is required, instead of using sulfur at all, a sulfur-containing organic compound is used as a vulcanizing agent (crosslinking agent). Morpholine disulfide such as Chemical Industry Co., Ltd., tetramethylthiuram disulphide such as Axel TMT (Kawaguchi Chemical Industry Co., Ltd.), and tetraethyl thiol such as Accel TET (Kawaguchi Chemical Industry Co., Ltd.). Examples thereof include dipentamethylene thiuram tetrasulfide such as raum disulfide and Axel TRA (trade name of Kawaguchi Chemical Industry Co., Ltd.), and are added in an amount of about 0.5 to 5 parts by weight based on 100 parts by weight of the base rubber. Usually, in sulfur vulcanization, about 1 to 6 types of vulcanization accelerators are used to improve vulcanizate properties, in particular, compression set and processing stability.
It is added in an amount of about 0.5 to 3 parts by weight based on 00 parts by weight. This includes thiazoles, thioureas, thiurams, dithiocarbamates, and guanidines.

Examples of the thiazoles include 2-mercaptobenzothiazole such as Axel M (trade name of Kawaguchi Chemical Co., Ltd.), dibenzothiazole disulfide such as Axel DM (trade name of Kawaguchi Chemical Co., Ltd.), and Axel CZ ( N such as Kawaguchi Chemical Industry Co., Ltd.
N-oxydiethylene-2-benzothiazolesulfenamide, such as cyclohexylbenzothiazole, Axel NS (trade name, manufactured by Kawaguchi Chemical Co., Ltd.), and N-, such as Axel BNS-R (trade name, manufactured by Kawaguchi Chemical Co., Ltd.) Examples include N, N-dicyclohexyl-2-benzothiazolesulfenamide such as t-butyl-2-benzothiazolesulfenamide and Axel DZ-G (trade name of Kawaguchi Chemical Industry Co., Ltd.). Examples of the thioureas include diethylthiourea and Axel 22-S such as Axel EUR (trade name, manufactured by Kawaguchi Chemical Industry Co., Ltd.).
(Trade name, manufactured by Kawaguchi Chemical Industry Co., Ltd.).

Examples of the tiraum include tetramethylthiuram disulfide such as Axel TMT (trade name manufactured by Kawaguchi Chemical Co., Ltd.), tetraethylthiuram disulfide such as Axel TET (trade name manufactured by Kawaguchi Chemical Co., Ltd.), and Axel TBT (trade name). Tetrabutyl thiuram disulfide such as Kawaguchi Chemical Co., Ltd .; dipentamethylene thiuram tetrasulfide such as Accel TRA (trade name of Kawaguchi Chemical Co., Ltd.); and Accel TS (trade name of Kawaguchi Chemical Co., Ltd.) And tetramethylthiuram monosulfide. Examples of the dithiocarbamates include zinc dimethyldithiocarbamate such as Accel PZ (trade name of Kawaguchi Chemical Co., Ltd.), zinc diethyldithiocarbamate such as Accel EZ (trade name of Kawaguchi Chemical Co., Ltd.), and Accel BZ (Kawaguchi Chemical Co., Ltd.). Examples thereof include zinc dibutyldithiocarbamate such as trade name (manufactured by Co., Ltd.) and tellurium dithiocarbamate such as Accel TL-PT (trade name manufactured by Kawaguchi Chemical Co., Ltd.). Examples of guanidines include diphenylguanidine such as Accel D (trade name, manufactured by Kawaguchi Chemical Industry Co., Ltd.).

As the foaming agent, a foaming agent used in ordinary EPDM can be applied to the sponge rubber composition of the present invention.
These include azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine,
4'-oxybis (benzenesulfonylhydrazine) and the like, and 1 to 1 part by weight based on 100 parts by weight of the base rubber.
About 0 part by weight is added. In addition, if necessary, decomposition aids, for example, inorganic salts such as zinc oxide and tribasic lead sulfate, metal soaps such as zinc stearate and lead stearate, and urea compounds are added in an amount of 1 to 100 parts by weight of the base rubber. About 10 parts by weight are used together. In the sponge rubber composition of the present invention, in order to obtain a composition of low hardness, and to assist in mixing and dispersing of compounding agents, rolling, extrusion and other molding operations are facilitated,
To increase the adhesiveness of unvulcanized rubber and make it easier to mold,
0 to 180 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the ethylene-propylene copolymer rubber of the base rubber.
About a part by weight of a softener is charged. It is necessary to consider the compatibility of the softener with the ethylene-propylene copolymer rubber, and for that purpose, it is preferable to use paraffin oil, naphthene oil, aromatic oil and the like.

As the softening agent for the paraffinic oil, Diana Process Oil PW-32, PW-90,
PW-150, PW-380, PS-32, PS-9
0, PS-430, PX-32, and PX-90 (trade names, manufactured by Idemitsu Kosan Co., Ltd.), Flexson 845 (trade names,
Esso Oil Co., Ltd. product name), Syntac PA-9
5, PA-100, PA-140 (trade names, manufactured by Kobe Oil Chemical Co., Ltd.), Cosmo Process 10, 40, 4
0C (above, trade names manufactured by Cosmo Oil Co., Ltd.), Sunper 110, 115, 120, 130, 1
50, 180, 2100, 2210, 2280 (above,
Nippon Sun Oil Co., Ltd. product name), Fukkor P-20
0, P-400, P-500 (trade names, manufactured by Fujikosan Co., Ltd.), Mitsubishi 10, Mitsubishi 12 (trade names, manufactured by Mitsubishi Petroleum Corporation), and the like.

The softening agent for the naphthenic oil includes:
Diana process oil NS-24, NS-100, N
M-26, NM-68, NM-150, NM-280,
NP-24, NU-80, NF-90 (all trade names manufactured by Idemitsu Kosan Co., Ltd.), Esso process oil 725, 7
65 (trade names, manufactured by Esso Oil Co., Ltd.), Syntax N-40, N-60, N-70, N-75, N-85
(The above is a product name of Kobe Oil Chemical Industry Co., Ltd.), Shelflex 371JY, 371N, 451, N-40, 2.
2,22R, 32R, 100R, 100S, 100S
A, 220RS, 220S, 260, 320R, 680
(The above are the product names of Shell Japan Co., Ltd.), Sunsen 310, 380, 410, 41
5,420,430,450,480,3215,41
30, 4240, Ciro Light R .; P. O.
(The above are trade names made by Nippon Sun Oil Co., Ltd.), Komorix No. 2 (trade name made by Nippon Oil Co., Ltd.)
150N, 1400N (trade name, manufactured by Fuji Kosan Co., Ltd.), Mitsubishi 20 (trade name, manufactured by Mitsubishi Petroleum Co., Ltd.), Naplex 32, 38 (trade name, manufactured by Mobile Oil Co., Ltd.), Petrex PN-3 ( Yamabun Yuka Co., Ltd.).

As the softener for the aromatic oil, Diana Process Oil AC-12, AC-460, AE
-24, AE-50, AE-200, AH-16, AH
-58 (trade name, manufactured by Idemitsu Kosan Co., Ltd.), Esso Process Oil 110, 120 (trade name, manufactured by Esso Oil Co., Ltd.), Syntax HA-10, HA-15, H
A-30, HA-35 (above, trade names made by Kobe Oil Chemical Co., Ltd.), Cosmo Process 40A (trade name, made by Cosmo Oil Co., Ltd.), J SO Aroma790 (trade name, made by Nippon Sun Oil Co., Ltd.), Komorex 300 , 700
(The above are the product names made by Nippon Oil Corporation), Aromax #
1, # 3, # 5 (these are the product names of Fujikosan Co., Ltd.),
Heavy process oil Mitsubishi 34, Mitsubishi 38, Mitsubishi 44 (Mitsubishi Oil Co., Ltd. product name), Mobilesol
K, 22, 30, 130 (all trade names, manufactured by Mobil Sekiyu KK), Petrex LPO-R, LPO-V, P
F-1, PF-2 (these are the product names of Yamabun Yuka Co., Ltd.)
And the like.

Di- (2-ethylhexyl) phthalate (DO) such as DOP (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.) and Vinicizer 80 (trade name, manufactured by Kao Corporation)
P), higher alcohol phthalates such as Leofrex 9P (trade name of Shell Japan Co., Ltd.) and Diasizer 11,99 (trade name of Mitsubishi Chemical Co., Ltd.), DIOP (Wacker-Ch)
diomioctyl phthalate (DIOP), Sansocisizer DOS
Di- (2-ethylhexyl) sebacate, such as (trade name, manufactured by Shin Nippon Rika Co., Ltd.), Alizona 208 (Alizona Chem, USA)
Isooctyl / tall oil fatty acid esters such as TBP (trade name of Daihachi Chemical Industry Co., Ltd.), and tributyl phosphate (TBP) such as TBP (trade name of Daihachi Chemical Industry Co., Ltd.); Tributoxyethyl phosphate (TBEP), Sansocizer TC
Tricresyl phosphate (TCP), such as P (trade name, manufactured by Shin Nippon Rika Co., Ltd.), cresyl diphenic phosphate (CDP), such as CDP (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.), Koremol CE 54
Diphenylalkanes such as No. 22 (trade name of BASF (Germany)), Thiokol TP-95 (Morton International)
di (butoxyethoxyethyl) adipate and the like can also be used.

As the softening agent, usually one or two kinds are appropriately used, and if necessary, different kinds of oils such as a blend of a naphthenic oil and a paraffin oil may be added in combination. In consideration of the abrasiveness of the surface of the sponge rubber layer when a roller is used, black sub, white sub, candy sub, golden factice, neo factice, and sulfur-free factice (trade names of Teman Sub Chemical Co., Ltd.) The sub (factice) is also 5 to 100 parts by weight of the base rubber.
About 50 parts by weight can be used together. In the present invention, the base rubber 1
10 to 150 parts by weight, preferably 2 to 100 parts by weight
0-100 parts by weight of filler are added. If the amount is less than 10 parts by weight, the effect of adding the filler is not obtained. If the amount exceeds 150 parts by weight, a composition having low hardness is difficult to obtain, and the kneading property of the rubber is deteriorated.

Aerosil 13 is used as the silica-based filler.
Dry silica, such as 0, 200, 300, 380, R972, and R974 (trade names, manufactured by Nippon Aerosil Co., Ltd.) and Leolo Seal QS13, QS30, QS38, QS102 (trade names, manufactured by Tokuyama Corporation), carplex # 67 , # 80, # 100, # 1120, XR,
22S, CS-5, CS-7 (trade names, manufactured by Shionogi Pharmaceutical Co., Ltd.), Shilton A, R-2 (trade names, manufactured by Mizusawa Chemical Industry Co., Ltd.) and Toksil AL-1, Gu,
U, UR, US (these are the product names of Tokuyama Corporation) and nip seals AQ, ER, LP, NA, NP, NS-
K, VN3 (above, product name made by Nippon Silica Co., Ltd.) and U
ltrasil VN3 (Degussa)
(Germany) and Hi-Sil 233 (P
PPG Industries (PPG Industry
ries) (trade name, manufactured by U.S.A.) and the like.

Further, carbon black or white glossy flower CC, D
Activated calcium carbonate such as D, O, U (the above-mentioned trade names made by Shiraishi Industry Co., Ltd.), special calcium carbonate like the white luster A, AA (the above-mentioned trade names made by Shiraishi Industry Co., Ltd.), Mistron Paper (Nippon Mistron Co., Ltd.) Magnesium silicate such as (trade name, manufactured by Co., Ltd.), Hytron, Hytron A, Microlite, US-100, US-150S,
Magnesium silicates such as US-150SS, Hi-Lac, Hi-Lac SS (trade names, manufactured by Takehara Chemical Industry Co., Ltd.), Wiener Clay A (hard clay: trade name, manufactured by Kawashige Co., Ltd.), hard top clay, soft clay, Crown clay (these are the product names of Shiraishi Calcium Co., Ltd.), silkanite, NN clay, special kaolin clay, hard bright, No. 5 clay, SPMA
Clay, Union Clay RC-1, Gromax Max LL,
Clays (such as Hydraite PX (trade name, manufactured by Takehara Chemical Industry Co., Ltd.) and JP-100 kaolin, 5M kaolin, NN kaolin, Hardsil, ST kaolin, cartabo (trade name, manufactured by Tsuchiya Kaolin Industry Co., Ltd.) Aluminum oxide), ST-100, ST-200, ST
-301 (these are the product names of Shiraishi Calcium Co., Ltd.)
0, Nucap200, Nucap390 (these are the product names of JM Huber (USA)) and Burgess KE, CB, 51
78, 2211 (above, Burgess Pigment (Bur
silane-modified clay such as ESS Pigment (trade name, manufactured by U.S.A.) may be used in combination as appropriate.

The sponge rubber composition of the present invention may be added with about 10 to 100 parts by weight of a filler based on 100 parts by weight of the base rubber, if necessary, for the purpose of dimensional stability and low cost. You may.

Green B is used as the filler.
all (trade name, manufactured by Inoue Lime Industry Co., Ltd.) and Tamapearl TP-121, TP-121R, TP222H, TP-
222HS, TP-123, TP-123CS (above,
Light calcium carbonate such as Okutama Industry Co., Ltd. and Silver W (Shiraishi Industry Co., Ltd.), Whitelon SSB, SB, S (above, Shiraishi Calcium Co., Ltd.) and Sunlight # 100, # 300, # 70
0, # 800, # 1000, # 1500, # 2000,
# 2200, # 2500 (these are trade names made by Takehara Chemical Industry Co., Ltd.), NS # 100, NS # 200, NS # 40
0, NS # 600, NS # 1000, NS # 2300,
NS # 2500, NS # 2700, NS # 3000, S
S # 30, SS # 80, NN # 200, NN # 500
(The above are the product names of Nitto Powder Chemical Co., Ltd.) and Super S, SS, SSS, 4S, # 1500, # 1700, #
Heavy calcium carbonate, such as 2000 (above, trade name of Maruo Calcium Co., Ltd.), JET-S (trade name of Asada Flour Milling Co., Ltd.) and talc GTA, CTA1, CTA2, fine powder talc (all, product of Kunimine Industries Co., Ltd. Name) or M
S, MS-P, MS-A, ND, SW, SW-E, SW
Talc (talc) such as A, SWB, SSS, SS, S (trade name of Nippon Talc Co., Ltd.), crystallite AA, VX-S, VX-S-2, VX-SR (trade name, Ryu Co., Ltd.) Mori brand name) and Min-U-Sil 5,1
0, 15, 30 (above, US Silica (U.S.A.)
Silica) (US), Imsil
A-10, A-15, A-25, A-108 (above,
Illinois Minerals
als) (USA) (trade name), quartz powder, JA
-30W, 325M (the above, trade name made by Asada Flour Milling Co., Ltd.) and NYAD325, 400, 1250, G (the above,
Wollastonite (trade name, manufactured by Nyco (USA)), Celit
e 270, 281, 501, 503, 505, 53
5,545,560,577, FC, SSC, Supe
r Floss, Snow Floss (trade name, manufactured by Johns-Manville (USA)) and radio lights # 100, # 20
0, # 300, # 500, # 500S, # 600, # 7
00, # 800, # 800-S, # 900, F, SP
Diatomaceous earth, zinc flower 2 such as F, Fine Flow A, Fine Flow B (these are brand names manufactured by Showa Chemical Industry Co., Ltd.)
Examples thereof include zinc oxide, aluminum sulfate, barium sulfate, calcium sulfate, titanium oxide, molybdenum disulfide, and the like, such as seeds (trade name, manufactured by Sakai Chemical Industry Co., Ltd.).
Several are used together with the reinforcing filler.

When the sponge rubber composition of the present invention is applied to a transfer roller or the like, it is required to have semi-conductivity. Therefore, if necessary, a conductivity-imparting agent such as conductive carbon black, conductive zinc oxide, Depending on the type, about 3 to 150 parts by weight of tin oxide, conductive titanium oxide or the like is appropriately added to 100 parts by weight of the base rubber. The sponge rubber composition of the present invention may contain, as necessary, about 0.3 to 5 parts by weight of a lubricant or an internal release agent with respect to 100 parts by weight of the base rubber in order to improve rubber kneadability and extrudability. Can be added, but adding too much will cause bloom, bleed or poor fusion, so depending on the type,
Usually, about 0.5 to 1 part by weight is added.

As the lubricant and the internal release agent, Mitsui High Wax 100P, 110P, 200P, 210P, 2
Low-molecular-weight polyethylene such as 20P, 320P, 420P (trade names, manufactured by Mitsui Petrochemical Industries, Ltd.), Lunac S-20, S-30, S-40 (trade names, manufactured by Kao Corporation) and FA-KR (Product name made by Nippon Yushi Co., Ltd.)
And ADEKA fatty acids SA-20, SA-300, SA-40
Stearic acid such as 0 (the trade name of Asahi Denka Co., Ltd.), fatty acid amide such as plastodine and plastrogin S (the trade name of Fujisawa Pharmaceutical Co., Ltd.), and amowax EBS (Lion Akzo Co., Ltd.) Product name)
Aflex42 (trade name, manufactured by Rein Chemi (Germany), Inc.)
Mixtures of polar compounds and surfactants such as
ol A60 (Seal and Zirakka (Sch
higher unsaturated fatty acid zinc such as ill & Seilacher (Germany), Struktol
EF44 (Seal and Zirakka (Schi
Special fatty acid zinc, such as ll & Seilacher (Germany), Struktol WB1
6 (Seal & Zirakkar)
A mixture of a fatty acid calcium and a fatty acid amide, such as Seillacher (trade name, manufactured by Germany), Stru
a mixture of a fatty acid ester and a fatty acid metal salt, such as ktol WB42 (trade name, manufactured by Schill & Seilacher (Germany)); Struktol WB212 (Schiel & Seilacher)
er) (trade name, manufactured by Germany), a mixture of a higher fatty acid ester hydrate and an inorganic carrier, Struktol
WB222 (Seal and Zirakka (Schi
polyhydric alcohol fatty acid esters such as ll & Seilacher (Germany), Struk
Organic silicone condensates such as tol WS180 (trade name, manufactured by Seal & Seilacher (Germany)), Str
Examples thereof include a mixture in which a high-molecular-weight natural aliphatic alcohol and an aliphatic soap are treated with an inert filler, such as uktol W33FL (trade name, manufactured by Seal & Seilacher (Germany)), an inert filler, paraffin wax, montan wax, and the like. Is done.

When the sponge roller of the present invention is applied to a transfer roller, a charging roller, or the like, the surface of the roller may be treated as necessary to prevent contamination of the photoreceptor or impart conductivity. A surface layer may be formed. As the surface layer, a reactive silicone compound such as an organic silicone polymer, a conductive urethane elastomer, N-methoxymethylated nylon, a conductive polyester, a fluororesin such as PFA or PVDF, etc. are sprayed, dipped and roll coated. 20-300μm by coating the coating and sleeve by the method
It is formed to a thickness of the order. Furthermore, in order to reduce the frictional resistance of the roller surface or to reduce the adhesive force, the roller surface may be subjected to treatment such as irradiation with ultraviolet light and exposure to ozone. The surface treatment methods as described above are all technical matters well known to those skilled in the art, and can be appropriately performed according to the purpose, application, and the like.

[0027]

Next, more specific examples of the roller according to the present invention will be described below, but the present invention is not limited to these examples. Example 1 First, Mitsui EPT40 was used as EPDM as a base rubber.
45 (trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd.) as a liquid ethylene-propylene copolymer
LENE67 (Uniroyal Chemical)
Company Inc. (U.S.A.) (trade name), 20 parts by weight of carbon black seaweed SO (trade name, manufactured by Tokai Carbon Co., Ltd.) as a filler, 70 parts by weight, and NS # 100, calcium carbonate (a product manufactured by Nitto Powder Chemical Co., Ltd. 40 parts by weight of Diana Process Oil PW380 (trade name of Idemitsu Kosan Co., Ltd.) as a softener.
Parts by weight, Vesta 1 which is calcium oxide as a dehydrating agent
8 (trade name, manufactured by Inoue Lime Industry Co., Ltd.) and 2 kinds of zinc oxide as zinc oxide (trade name, manufactured by Sakai Chemical Industry Co., Ltd.)
5 parts by weight, 1 part by weight of Lunac S-20 (trade name, manufactured by Kao Corporation) as stearic acid, and 4 parts by weight as a foaming agent.
2 parts by weight of 4'-oxybis (benzenesulfonyl hydrazide (Neocervone N # 5000: trade name, manufactured by Eiwa Kasei Kogyo Co., Ltd.);
1.5 parts by weight of esh, Accel PZ as a vulcanization accelerator
1.0 parts by weight (trade name of Kawaguchi Chemical Co., Ltd.) and 1.5 parts of Accel BZ (trade name of Kawaguchi Chemical Co., Ltd.)
Parts by weight and Accel M (trade name of Kawaguchi Chemical Co., Ltd.)
Weighed 1.5 parts by weight and 0.7 parts by weight of Accel TRA (trade name, manufactured by Kawaguchi Chemical Industry Co., Ltd.), kneaded each with a well-known rubber kneading roll, and spun rubber for unvulcanized rollers. A composition was obtained. That is, the total composition of EPDM and the liquid ethylene-propylene copolymer is 100 parts by weight, and the composition contains 2 parts by weight of a foaming agent. The Moon-viscosity was measured at 100 ° C. in accordance with JIS K 6300 for performance evaluation. next,
The sponge rubber composition for a roller of this example was extruded with a vented extruder using a crosshead together with a core having an outer diameter of 8 mm and a rubber portion having a total length of 320 mm while being vacuum-extracted. A sulfuric acid rubber layer was formed. Next, this cored bar was placed in a continuous furnace at 180 ° C., heated, vulcanized and foamed to produce a sponge rubber roller.

Example 2 EPDM was used as a base rubber in Example 1
A sponge rubber roller was manufactured in the same manner as in Example 1 except that the sponge rubber roller was changed to 05A (trade name, manufactured by Sumitomo Chemical Co., Ltd.). Example 3 EPDM as a base rubber of Example 1 was prepared using Esplen E
Example 1 was changed to 90 parts by weight of 5754 (trade name, manufactured by Sumitomo Chemical Co., Ltd.), and the addition amount of TRILENE 67 as a liquid ethylene-propylene copolymer was changed from 20 parts by weight to 10 parts by weight. Similarly,
A sponge rubber roller was manufactured. Example 4 EPDM as a base rubber of Example 1 was prepared using Esplen E
5754 (trade name, manufactured by Sumitomo Chemical Co., Ltd.) A sponge rubber roller was manufactured in the same manner as in Example 1 except that the weight was changed to 80 parts by weight.

Example 5 EPDM as the base rubber of Example 1 was replaced with Mitsui EPT4
Example 1 except that the amount was changed to 97 parts by weight, and the addition amount of TRILENE 67 as a liquid ethylene-propylene copolymer was changed from 20 parts by weight to 3 parts by weight. In the same way as
A sponge rubber roller was manufactured. Example 6 EPDM as a base rubber of Example 1 was replaced with Mitsui EPT4
021 (trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd.) was changed to 95 parts by weight, and the addition amount of TRILENE 67 as liquid ethylene-propylene was changed from 20 parts by weight to 5 parts by weight in the same manner as in Example 1. Thus, a sponge rubber roller was manufactured.

Comparative Example 1 For comparison with Example 1 , the addition amount of Mitsui EPT4045 as EPDM of Example 1 was changed from 80 parts by weight to 100 parts by weight.
A sponge rubber roller was manufactured in the same manner as in Example 1, except that the amount of TRILENE 67 as a liquid ethylene-propylene copolymer was changed from 20 parts by weight to 0 parts by weight. Comparative Example 2 For comparison with Example 1, the EPDM of Example 1 was changed to Esplene 505A, the addition amount was changed from 80 parts by weight to 100 parts by weight, and the addition amount of TRILENE 67 was changed from 20 parts by weight to 0 parts by weight. Example 1 except for changing to parts by weight
In the same manner as in the above, a sponge rubber roller was manufactured. Comparative Example 3 For comparison with Example 1, the EPDM of Example 1 was changed to Esplen E5754, the addition amount was changed from 80 parts by weight to 100 parts by weight, and the addition amount of TRILENE 67 was changed from 20 parts by weight to 0 parts by weight. A sponge rubber roller was manufactured in the same manner as in Example 1 except that the amount was changed to parts by weight. Comparative Example 4 For comparison with Example 1, the EPDM of Example 1 was changed to Mitsui EPT4021, the addition amount was changed from 80 parts by weight to 100 parts by weight, and the addition amount of TRILENE 67 was changed from 20 parts by weight to 0 parts by weight. Example 1 except for changing to parts by weight
In the same manner as in the above, a sponge rubber roller was manufactured.

Next, Examples 1 to 6 and Comparative Example 3
After polishing the sponge roller of Comparative Example 4 so that the outer diameter becomes 24 mm, SRIS (Japanese Rubber Association Standard)
The sponge hardness was measured with an Asker C hardness meter (trade name, manufactured by Kobunshi Keiki Co., Ltd.), which is a sponge rubber hardness meter specified in the 0101 Expansion Rubber Test Method. Next, after the sponge layer of this sponge roller was sliced so as to have a width of 2 mm in the circumferential direction, the vicinity of the center of the sponge layer portion having a thickness of 8 mm was photographed with a scanning electron microscope at a magnification of 40 times, and The average cell diameter of each sample was determined from the cell size. The mixing ratio (composition of the composition) and the evaluation results of each of the examples and comparative examples are shown in Table 1 below.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

According to the evaluation results shown in Table 1, the roller 1 using the sponge rubber composition for a roller of Examples 1 to 6 has a low sponge hardness and an average cell diameter of 25.
It was found that the cell had a relatively fine cell diameter of 0 μm or less. The reason why the liquid ethylene-propylene copolymer improves the cell diameter is not clear, but EPDM as the base rubber is involved not only in the effect as a softener but also in the vulcanization reaction when vulcanizing and foaming. I guess it is because of Furthermore, in Comparative Examples 1 and 2, it was found that extrusion could not be performed and a roller could not be obtained. Further, the sponge roller 1 using the sponge rubber composition for a roller of Comparative Example 3 has a relatively fine cell diameter, but is unsuitable as a sponge roller such as a transfer roller due to its high hardness. It turned out to be. Further, in the sponge roller 1 using the sponge rubber composition for a roller of Comparative Example 4, it was found that although the extrudability was good, the sponge roller was not practical because of a large cell diameter and a large variation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a sponge roller using a sponge rubber composition according to the present invention.

[Explanation of symbols]

 1 sponge roller 2 core metal 3 sponge rubber layer

Claims (3)

[Claims] 1. A sponge rubber composition comprising an ethylene-propylene copolymer rubber and a liquid ethylene-propylene copolymer. 2. Ethylene-propylene copolymer rubber 100
The sponge rubber composition according to claim 1, wherein 3 to 20 parts by weight of the sponge rubber composition is replaced with the liquid ethylene-propylene copolymer. 3. A method for producing a sponge rubber roller in which a sponge rubber layer made of ethylene-propylene copolymer rubber is formed on the outer periphery of a cored bar, wherein the sponge rubber composition according to claim 1 or 2 is heated, The above-mentioned manufacturing method, wherein the method is vulcanized and foamed.