JP3291228B2 - Rubber roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber roller used in a paper feed mechanism of a laser printer, an electrostatic copying machine, a plain paper facsimile machine, an automatic teller machine (ATM), and the like. It is intended to improve the productivity of rubber rollers capable of maintaining transportability for a long period of time.

[0002]

2. Description of the Related Art Rubber compositions used for OA equipment such as electrostatic copying machines, laser printers, and facsimile machines, and paper feed rollers for automatic teller machines are required to have a high coefficient of friction. . This is because, when the roller surface is worn due to repeated use and the coefficient of friction is reduced, a slip occurs, and the paper conveyance force is reduced. For this reason, a rubber composition mainly composed of EPDM rubber (ethylene-propylene-diene copolymer rubber) having excellent mechanical strength has been used as this type of rubber composition. In particular, EPDM rubber has excellent ozone resistance and is suitable for a paper feed roller of an image forming apparatus that generates ozone in a machine such as a copying machine or a laser printer using electrophotography.

Accordingly, the present inventors have previously reported in Japanese Patent Application No.
-63387 (JP-A-9-254275).
A rubber roller obtained by vulcanizing and molding a rubber composition containing an oil-extended EPDM rubber (ethylene-propylene diene copolymer rubber), wherein no filler is mixed in the rubber composition, or And a rubber roller in which 15 parts by weight or less of a filler is blended with respect to 100 parts by weight of the rubber component. Such a rubber roller vulcanizes and molds oil-extended EPDM rubber, and can maintain a high friction coefficient for a long period of time and obtain excellent abrasion resistance by minimizing the blending amount of a filler. It is like that.

[0004]

As described above, conventionally, a rubber roller made of a rubber composition containing EPDM rubber as a main component has been used as a paper feed roller for OA equipment, automatic teller machines and the like. Usually, when this kind of rubber roller is cylindrical and mounted on a paper feed mechanism of an OA device or an automatic teller machine, the rubber roller is used by being fitted around the outer peripheral surface of a hard resin or metal roller shaft. Also, if necessary,
In order to increase the coefficient of friction of the rubber roller surface, the roller surface is made uneven by polishing. However, EPDM rubber has a small number of double bonds and a small number of cross-linking points, and therefore has a low tensile strength (TB, JIS dumbbell No. 3 type K-6301) and a low tear strength (TRA, A type, K-6301).
For this reason, when the roller is inserted into the roller shaft or when the surface of the roller is polished, the roller may be cracked or chipped.
This causes a problem that productivity is reduced.

The present invention has been made to solve the above problems, and has as its object to provide a rubber roller having a high friction coefficient and excellent wear resistance with high productivity.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and as a result, blended an EPDM rubber containing at least 50% by weight or more of EPDM rubber and an ionomer resin at a certain ratio, And EPDM
By dispersing the system rubber in the ionomer resin,
It has been found that the tensile strength and the tear strength of the rubber composition can be improved, and the present invention has been completed.

That is, according to the present invention, the EPD
An ionomer resin is used in an amount of 25 to 1 based on 100 parts by weight of an EPDM rubber containing at least 50% by weight of M rubber.
The rubber roller was characterized in that the rubber composition was prepared by dynamically vulcanizing the EPDM rubber by sulfur vulcanization or resin vulcanization and dispersing the rubber composition in the ionomer resin into a roller shape. providing.

In the rubber roller of the present invention, since the EPDM rubber is finely dispersed in an ionomer resin having relatively low hardness and high strength and moderate elasticity, the entire rubber composition ( It is possible to improve the tensile strength and the tear strength of the rubber roller, and to eliminate the occurrence of "cracking" or "break" of the roller during the work of fitting the roller into the roller shaft or the work of polishing the roller surface.

Conventionally, a rubber composition in which a thermoplastic resin or a thermoplastic elastomer is blended with EPDM rubber has been proposed in order to improve the compression set and the like of EPDM rubber. For example, a rubber composition obtained by blending a thermoplastic crystalline polyolefin resin with EPDM proposed in Japanese Patent Publication No. 58-46138 was formed into a roller shape (cylindrical shape) and used as a rubber roller for paper feeding. Further, since the hardness of the thermoplastic crystalline polyolefin resin is high, it is difficult to fit the rubber roller to the roller shaft core, and the friction coefficient of the roller is reduced, so that a good paper conveying force cannot be obtained. In addition, E proposed in Japanese Patent Application Laid-Open No. 8-143200
A rubber composition obtained by blending a urethane-based thermoplastic elastomer (TPU) with PDM was molded into a roller shape (cylindrical shape) and used as a rubber roller for paper feeding. In this case,
Due to the large polarity difference between EPDM and TPU, EPD
M could not be finely dispersed in the TPU, not only had a low coefficient of friction, but also had "cracks" and "breaks" during the work of inserting the roller into the roller shaft and the work of polishing the roller surface.

[0010] In the present invention, E which constitutes an EPDM rubber containing at least 50% by weight or more of EPDM rubber.
Rubber components other than PDM rubber include butyl rubber, butadiene rubber, isoprene rubber, styrene butadiene rubber, chloroprene rubber, natural rubber, 1,2-polybutadiene, acrylonitrile-butadiene rubber, ethylene propylene rubber, acrylic rubber, and chlorosulfonated polyethylene. One or two or more selected from the following can be used. As the EPDM rubber, oil-extended or non-oil-extended or a mixture of both can be used. Also,
The diene component is not particularly limited. For example, ethylidene norbornene (ENB), dichloropentadiene (DC
PD) or the like can be used.

By using the above EPDM rubber,
The excellent ozone resistance and heat resistance of the EPDM rubber itself make it possible to achieve both the ozone resistance and the heat resistance required for a rubber roller used in OA equipment. Also,
The polarity of the EPDM rubber is similar to that of the ionomer resin, and the compatibility with the ionomer resin is good, so that the processability of the rubber in the dynamic vulcanization step is also improved. Therefore, EP
The DM rubber is uniformly and finely dispersed in the ionomer resin by dynamic vulcanization, and imparts high durability and a high friction coefficient to the rubber roller. EPDM rubber is EPD
More preferably, it is contained in the M-based rubber in an amount of at least 80% by weight.
It is better to use rubber. In the present invention, 100 parts by weight of the EPDM rubber means that the rubber polymer content is 100 parts by weight. When an oil-extended rubber is used, the rubber-polymer content obtained by subtracting the oil component from the oil-extended rubber is 100 parts by weight.
Represents parts by weight.

The reason that the ionomer resin is blended in an amount of 25 to 100 parts by weight with respect to 100 parts by weight of the EPDM rubber is that when the ionomer resin is less than 25 parts by weight, the vulcanization of the EPDM rubber is carried out because the resin content is small. The product cannot be dispersed in the ionomer resin, the processed product becomes a powder of vulcanized rubber, and cannot be processed into a roller shape. If it exceeds 100 parts by weight, the hardness of the rubber roller becomes too high, resulting in friction. This is because the coefficient decreases, and particularly, the coefficient of friction decreases significantly due to repeated use.

As the ionomer resin, for example, metal ion neutralized products such as ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and ethylene-acrylic acid-methacrylic acid terpolymer can be used. . Examples of neutralizing metal ions include alkali metal ions (sodium ion, potassium ion, lithium ion, etc.), divalent metal ions (zinc ion, calcium ion, magnesium ion, copper ion, manganese ion, etc.), and trivalent metal ions. (Aluminum ion, neodymium ion, etc.). In particular, from the viewpoint of ease of molding of the rubber composition, it is preferable to use an ionomer resin having an MFR (melt frame rate) value of 5.0 or more measured by JIS K-6760. An ionomer resin having a value of 10 or more is more preferable. Specific examples of the ionomer resin having an MFR value of 10 or more include, for example, Himilan 1702 and Himilan 1555 (both manufactured by Mitsui / Dupont Polychemical Co., Ltd.).

The dynamic vulcanization of the EPDM rubber may be either sulfur vulcanization or resin vulcanization. However, from the viewpoint of excellent reactivity between the vulcanizing agent and the EPDM rubber and no occurrence of blooming or the like, It is preferably carried out by resin vulcanization (claim 2).

Examples of the resin vulcanizing agent used for vulcanizing the resin include alkylphenol / formaldehyde resin, melamine / formaldehyde condensate, triazine / formaldehyde condensate, sulfurized / p-tert-butylphenol resin, and alkylphenol / sulfide. Resin, hexamethoxymethyl melamine resin and the like. Among these, it is preferable to use an alkylphenol-formaldehyde resin (reactive phenol resin). When an alkylphenol / formaldehyde resin is used, good crosslinking can be obtained as compared with the case where another resin vulcanizing agent is used, and a rubber roller having excellent heat resistance and abrasion resistance and having less compression set can be obtained. it can. This is considered because the crosslink density changes. In addition, a catalyst such as tin chloride can be added together with the resin vulcanizing agent.

Although the amount of the resin vulcanizing agent varies depending on the type of the vulcanizing agent, it is generally used in an amount of 3 to 20 parts by weight, preferably 10 to 15 parts by weight, per 100 parts by weight of the EPDM rubber.

When performing sulfur vulcanization, a vulcanization accelerator can be used in combination with a vulcanizing agent (sulfur).
Examples of the vulcanization accelerator include slaked lime, magnesia (M
gO), litharge (PbO) and the like, and organic promoters described below can be used. Examples of the organic accelerator include 2-mercaptobenzothiazole,
A thiazole vulcanization accelerator such as N-cyclohexyl-2-benzothiazolesulfene, n-butylamine, t
aliphatic primary compounds such as tert-butylamine and propylamine;
Oxidative condensate of amine and 2-mercaptobenzothiazole, oxidative condensate of aliphatic secondary amine such as dicyclohexylamine, pyrrolidine, piperidine and 2-mercaptobenzothiazole, alicyclic primary amine and 2-mercaptobenzothiazole , A sulfenamide-based vulcanization accelerator such as an oxidized condensate of a morpholine compound with 2-mercaptobenzothiazole, tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethyl Thiuram-based vulcanization accelerators such as thiuram dimonosulfide (TETD), tetrabutylthiuram dimonosulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT), and zinc dimethyldithiocarbamate (ZnMD)
C), zinc diethyldithiocarbamate (ZnED
C), zinc di-n-butylcarbamate (ZnBDC)
And the like. These vulcanization accelerators can be used alone or in admixture of two or more.

[0018] The amount of the vulcanizing agent (sulfur) is generally
The amount is 0.5 to 3 parts by weight, preferably 1 to 2 parts by weight, per 100 parts by weight of the M rubber. The vulcanization accelerator is used in an amount of 0.5 to 6 parts by weight, preferably 2 to 5 parts by weight, per 100 parts by weight of EPDM rubber.

In the present invention, a thermoplastic resin other than the ionomer resin may be blended in the rubber composition, if necessary. Examples of such other thermoplastic resins include ethylene ethyl acrylate resin, ethylene vinyl acetate resin, polyethylene resin, polypropylene resin, ethylene-methacrylic acid copolymer resin, styrene-based thermoplastic elastomer, and polyester-based thermoplastic elastomer. . When the other thermoplastic resin is blended, the amount is preferably not more than 30 parts by weight, more preferably not more than 10 parts by weight based on 100 parts by weight of the ionomer resin. This is because if the amount of the thermoplastic resin in the rubber composition is too large, the compatibility between the thermoplastic resin and the EPDM rubber becomes poor, and the EPDM rubber is hardly finely dispersed during dynamic vulcanization. As a result, the durability and the coefficient of friction of the rubber composition (roller) tend to decrease. Further, in addition to the above-mentioned other thermoplastic resins, a process oil, an antioxidant, a filler and the like may be blended as required. Examples of the filler include powders of silica, carbon black, clay, talc, calcium carbonate, dibasic phosphite (DLP), basic magnesium carbonate, alumina and the like. When a filler is compounded, it is preferable to add the filler in a range not exceeding 15 parts by weight based on 100 parts by weight of the EPDM rubber. This is because, although the compounding of the filler is effective in improving the tensile strength and the tearing strength, if the compounding is too large, the flexibility of the rubber roller tends to decrease and the coefficient of friction tends to decrease.

In the present invention, the content of the polymer (EPDM rubber + ionomer resin + other thermoplastic resin to be blended as required) is 45 to 9 based on the whole rubber composition.
It is preferably 5% by weight, particularly preferably 60 to 95% by weight.
This is because when the content ratio of the polymer decreases, blooming or the like easily occurs. Further, the total compounding ratio of the EPDM rubber and the ionomer resin to 50 parts by weight of the total polymer is 50% or more, preferably 7%.
It is good to make it 5% or more. This depends on the usage ratio of the EPDM rubber and the ionomer resin.
When the total blending ratio of the M-based rubber and the ionomer resin is less than 50% based on the total polymer content, the ozone resistance of the EPDM rubber and the improvement of the tensile strength and tear strength of the ionomer resin are sufficiently exhibited. This is because there is a risk of disappearing.

In the present invention, as described above,
2 parts ionomer resin per 100 parts by weight of DM rubber
The ionomer resin is used in the range of 5 to 100 parts by weight, but it is preferable to use the ionomer resin in a range not exceeding 40 parts by weight (25 to 40 parts by weight), and particularly 30 parts by weight or less (25 to 3 parts by weight).
0 parts by weight). This is because by reducing the amount of the ionomer resin, the hardness of the rubber composition is lowered, and the number of frictional locks when the roller is formed can be greatly reduced. Is made smaller and the workability of fitting is improved.

In general, the surface of a molded rubber roller is polished to increase the coefficient of friction of the roller surface. However, the surface of the rubber roller of the present invention is preferably polished. When the polishing is performed, the ionomer resin is easily polished, and the EPDM rubber is hard to be polished. Therefore, unevenness due to the difference in the degree of polishing between the two is effectively formed on the roller surface. Therefore, the surface of the rubber roller can obtain a large gripping force on the paper, and the friction coefficient can be greatly increased.

The rubber composition of the present invention is prepared by melting and kneading a mixture of a polymer component such as an EPDM rubber and an ionomer resin, a vulcanizing agent and various compounding agents to be compounded as required, and forming the kneaded product into a roller. It manufactures by doing. EPDM rubber melted in the process of melt-kneading is dynamically vulcanized, finely dispersed in the ionomer resin and crosslinked. Melt kneading can be performed by a known method, for example,
Using a known rubber kneading device such as an open roll, a Banbury mixer, and a twin screw extruder, a temperature of 160 to 200 ° C.
Knead for about 10 hours.

The molding is performed, for example, by attaching a die for extruding into a tube at the tip of the kneading device and extruding the kneaded material.
Various methods can be used, such as polishing and cutting to form a roller, or pelletizing the kneaded material, forming the mixture into a tube by injection molding, and then polishing and cutting to form a roller.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments (examples) of the present invention will be described together with comparative examples.

Examples 1 to 8 ENB-based oil-extended EPDM
An ionomer resin and a filler are blended in the proportions shown in Table 1 with respect to 200 parts by weight of rubber (100 parts by weight of an EPDM rubber polymer), and further additives described below are blended, and the mixture is melt-kneaded. The oil-extended EPDM rubber was dynamically vulcanized to produce a rubber composition, and a rubber roller was completed using the rubber composition. That is, various raw materials including the above EPDM rubber were charged into a twin-screw extruder HTM50 (manufactured by IPEC Co., Ltd.), kneaded while heating to 160 ° C. to 200 ° C., and vulcanized with resin (Example 1). -7) or dynamic vulcanization by sulfur vulcanization (Example 8) while extruding the rubber composition. A die was attached to the tip of the extruder, and the rubber composition was extruded into a tube. Then, after the tube-shaped rubber composition was polished, the rubber composition was cut into a predetermined length to prepare a rubber roller having an outer diameter of 20 mm, an inner diameter of 9 mm, and a width of 10 mm.

[0027]

[Table 1]

Example 9 An ionomer resin 7 was added to a mixed rubber of 100 parts by weight of an ENB oil-extended EPDM rubber (50 parts by weight of an EPDM rubber polymer) and 50 parts by weight of butyl rubber.
5 parts by weight, each additive described below is further compounded, and the mixture is melt-kneaded under the same kneading conditions as described above to dynamically vulcanize the oil-extended EPDM rubber to prepare a rubber composition. A rubber roller having the same dimensions as above was completed with the rubber composition. The dynamic vulcanization was performed by resin vulcanization.

Example 10 100 parts by weight of ENB-based oil-extended EPDM rubber (50 parts by weight of EPDM rubber polymer)
The oil-extended EPDM rubber is obtained by compounding 75 parts by weight of an ionomer resin with 50 parts by weight of butadiene rubber, and further blending each of the additives described below, and melt-kneading the mixture under the same kneading conditions as described above. A rubber composition was prepared by dynamic vulcanization, and a rubber roller having the same dimensions as above was completed with the rubber composition. The dynamic vulcanization was performed by resin vulcanization.

EXAMPLE 11 160 parts by weight of ENB-based oil-extended EPDM rubber (EPDM rubber polymer content: 80 parts by weight)
The oil-extended EPDM rubber is obtained by blending 75 parts by weight of an ionomer resin with a mixed rubber of 20 parts by weight of butadiene rubber and further blending each of the additives described below, and then kneading and kneading the mixture under the same kneading conditions as described above. A rubber composition was prepared by dynamic vulcanization, and a rubber roller having the same dimensions as above was completed with the rubber composition. The dynamic vulcanization was performed by resin vulcanization.

In the above, the oil-extended EPDM rubber uses Esplen E670F (manufactured by Sumitomo Chemical Co., Ltd.), and the ionomer resin has an MFR (JIS K-6760) of 14 g / g.
Himilan 170 consisting of a Zn ion neutralized product of a terpolymer of ethylene-acrylic acid-methacrylic acid for 10 minutes
2 (manufactured by DuPont Mitsui Polychemicals), Butyl 268 (manufactured by Nippon Synthetic Rubber) for butyl rubber, BR11 (manufactured by Nippon Synthetic Rubber) for butadiene rubber, and silica (Nippon Silica Industries, Ltd.) (VN-3) was used.

In the case of resin vulcanization (Examples 1 to 7,
9, 10, 11) are phenolic resin vulcanizing agents (Taoka Chemical Industry Co., Ltd.) reactive with 5 parts by weight of zinc oxide (Zinc Hua No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd.) as a vulcanizing additive. ),
Tack roll 250-III) 12 parts by weight was used.

In the case of sulfur vulcanization (Example 8), 5 parts by weight of zinc oxide (manufactured by Mitsui Mining & Smelting Co., Ltd.) and 1 part by weight of stearic acid (manufactured by NOF Corporation) were used as vulcanizing additives. Department and
Powder sulfur (Tsurumi Chemical Co., Ltd.) and vulcanization accelerator (Ouchi Shinko Chemical Co., Ltd., Noxeller TET, Bz, C
and 7.5 parts by weight of z).

To examine the wear resistance, the rubber roller prepared in Examples 1 to 11 was attached to
A4 size paper (PPC paper manufactured by Fuji Xerox Office Supply Co., Ltd.) 150 under the conditions of ° C. and 55% humidity
A paper passing test was performed in which 00 sheets were passed for 7.5 hours. The amount of wear (mg) was determined by measuring the weight of each rubber roller before and after the paper passing test.

The coefficient of friction was measured by the following method as shown in FIG. That is, the rubber roller 1 and the plate 3
A4 size PPC connected to load cell 5
The paper 4 was sandwiched, and a load W (W = 250 g) was applied to the rotating shaft 2 of the rubber roller 1 as shown by a black arrow in FIG. Then temperature 2
Under the conditions of 2 ° C. and 55% humidity, the rubber roller 1 was
The medium is rotated at a peripheral speed of 300 mm / sec in a direction indicated by a solid arrow a, and a force F (g) and a load W (250 g) generated in a direction indicated by a white arrow in FIG. Was used to determine the friction coefficient ν from the following equation.

[0036]

Ν = F (g) / W (g)

The productivity was evaluated under the same conditions as in the conventional rubber roller production process, after polishing 50 pieces with a grindstone, observing the surface of the rubber roller, and checking for "breaks" and "cracks".
Was performed by counting the number of occurrences.

The workability was evaluated by making each roller 10 mm in diameter.
The time required for the process of inserting 50 pieces into a hard resin core wet with ethyl alcohol and manually inserting the pieces was measured, the average time required for each piece was calculated and obtained, and this average time was compared. Was.

On the other hand, in Comparative Example 1, the same formulation as in Example 8 was used except that no ionomer resin was used.
The mixture was kneaded at 0 ° C. to prepare a mixture, and the mixture was injected into a mold and vulcanized and molded in the mold at 170 ° C. by sulfur vulcanization to prepare a rubber roller. The dimensions of this rubber roller were the same as those of the rubber roller of the example.

In Comparative Examples 2 to 5, the thermoplastic resins other than the ionomer resin were blended in place of the ionomer resin, and no filler was blended. Examples 1 to 7, 9, 10, 11
A rubber roller was prepared by performing the same resin vulcanization as described above.

In Comparative Example 6, the compounding amount of the ionomer resin was E
A rubber roller was prepared by performing the same sulfur vulcanization as in Example 8 without adding a filler to 20 parts by weight with respect to 100 parts by weight of the PDM rubber.

In Comparative Example 7, the amount of the ionomer resin was changed to E
Rubber rollers were prepared by resin vulcanization in the same manner as in Examples 1 to 7, 9, 10 and 11 without adding a filler to 20 parts by weight with respect to 100 parts by weight of PDM rubber.

In Comparative Example 8, the compounding amount of the ionomer resin was E
A rubber roller was produced by resin vulcanization in the same manner as in Examples 1 to 7, 9, 10 and 11 without adding a filler to 125 parts by weight with respect to 100 parts by weight of PDM rubber.

In Comparative Example 9, a rubber roller was prepared in the same manner as in Example 3 except that peroxide was used as a vulcanizing additive.

The other thermoplastic resins used in Comparative Examples 2 to 5 are shown in Table 2 below.
75 parts by weight based on 100 parts by weight of M rubber.

[0046]

[Table 2]

In Comparative Examples 6 and 7, since the amount of the ionomer resin was small, the powder was vulcanized rubber powder, and a rubber roller could not be formed. In Comparative Example 9, the peroxide reacted explosively during kneading, and also reacted with the ionomer resin, making processing impossible, and a rubber roller could not be produced.

Table 3 shows the test results of Examples 1 to 11 and Comparative Examples 1 to 5 and 8 in which rubber rollers could be prepared.
Shown in

[0049]

[Table 3]

The coefficient of friction in parentheses in Table 3 is a value after a paper passing test. As shown in Table 3, Examples 1 to 11
In each case, the number of "cracks and chips" during polishing is 0,
Excellent productivity. In particular, the coefficient of friction is also 2.2 to 2.
4. Even after the wear evaluation, the wear amount was 2.1 to 2.2, and the wear amount was as small as 13 to 23 mg. The results of the workability of the fitting to the roller shaft were also good at 5.1 to 7.8 / sec.

Further, the rubber rollers (EPD) of Examples 4 and 8
M rubber (100 parts by weight) and ionomer resin (75 parts by weight)), the friction coefficient after storing the rubber roller for 6 months was measured. As a result, Example 4 in which resin vulcanization was performed
Was 2.4 after storage for 6 months, and no deterioration in quality occurred. On the other hand, the rubber roller of Example 8 which had been subjected to sulfur vulcanization had blooming in which the surface slightly whitened after storage for 6 months, and had a coefficient of friction of 2.0 after storage for 6 months. In the case of sulfur vulcanization, the coefficient of friction after storage for 6 months was lower than that in the case of resin vulcanization, but still maintained a value that was satisfactory for use as a rubber roller.

In Examples 9 to 11, a mixed rubber obtained by mixing a dynamically vulcanizable rubber (butyl rubber, butadiene rubber) other than the EPDM rubber with the EPDM rubber in the same amount or less as the EPDM rubber was used. Although used, the dispersibility of the rubber was reduced due to poor compatibility between the ionomer resin and rubber that could be dynamically vulcanized (butyl rubber, butadiene rubber) other than EPDM rubber. For this reason, these Examples 9-11
Although the same amount of ionomer resin was used as the above, the abrasion resistance of the rubber was slightly lower than that of Example 4 using EPDM rubber alone. From this, it was confirmed that it is preferable to use EPDM rubber alone as the rubber.

Comparative Example 1 (EPDM rubber was the only polymer component and no ionomer resin was blended) and Comparative Examples 4 and 5
(Polymer components are EPDM rubber and low density polyethylene,
The polymer components EPDM rubber and urethane-based thermoplastic elastomer) often had "chips" and "cracks" at the time of polishing and were inferior in productivity. In Comparative Examples 4 and 5, the wear amount was 37 mg, and the wear resistance was extremely poor. Also,
In Comparative Example 5, the coefficient of friction was small and the basic performance as a paper feed roller was poor.

Comparative Examples 2 and 3 (where the polymer component is EPDM
In the case of rubber and polyethylene, the polymer components of which were EPDM rubber and polypropylene), there was no "cracking or chipping" at the time of polishing, but the workability of fitting the roller shaft was extremely poor, and some rubber rollers were broken at the time of fitting. In addition, the coefficient of friction is extremely small and the amount of wear is large, so that it is unsuitable as a paper feed roller.

Comparative Example 8 had a composition in which 125 parts by weight of an ionomer resin was blended with 100 parts by weight of EPDM, and the friction coefficient was as low as 2.0 because of a large blending ratio of the ionomer resin. The coefficient of friction dropped to 1.6. Therefore, good paper feeding performance cannot be maintained.

[0056]

As is apparent from the above description, according to the present invention, the friction coefficient is large, the wear resistance is excellent, and
It is possible to obtain a rubber roller that does not cause "cracking" or "breaking" of the roller when the roller is fitted into the roller shaft core or when the roller surface is polished. Therefore, a rubber roller having excellent paper feeding performance can be manufactured with high productivity.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an apparatus for measuring a coefficient of friction of a rubber roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber roller 2 Rotating shaft 3 Plate 4 PPC paper 5 Load cell

Continuation of the front page (51) Int.Cl. ⁷ identification code FI C08L 23/16 C08L 23/16 23/26 23/26 (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 5/06 B29D 31/00 B41J 13/076 B65H 27/00 C08L 9/00 C08L 23/16 C08L 23/26

Claims (4)

(57) [Claims] 1. An ionomer resin is blended in an amount of 25 to 100 parts by weight with respect to 100 parts by weight of an EPDM rubber containing at least 50% by weight of EPDM rubber.
A rubber roller comprising a rubber composition obtained by dynamically vulcanizing a PDM rubber by sulfur vulcanization or resin vulcanization and dispersing the rubber composition in the ionomer resin into a roller shape. 2. The rubber roller according to claim 1, wherein the EPDM rubber is dynamically vulcanized by resin vulcanization. 3. The rubber composition according to claim 1, wherein the rubber composition is EPDM rubber 100.
The rubber roller according to claim 1 , wherein the rubber roller contains 15 parts by weight or less of the filler with respect to part by weight. 4. A rubber roller according to any one of claims 1 to 3 roller surface is polished.