JP3124492B2 - Rubber composition for feed 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 composition for a paper feeding and conveying roller and a paper feeding and conveying roller. The present invention
More specifically, for a paper feed conveyance roller containing a rubber component containing a copolymer rubber obtained by copolymerizing a monomer containing ethylene and propylene and further containing a diene, and a diene rubber. The present invention relates to a rubber composition and a paper feed roller obtained by vulcanizing the rubber composition.

[0002]

2. Description of the Related Art In general, ozone is generated in an electrophotographic copying machine, and rubber parts such as a paper feed roller used in the electrophotographic copying machine are required to have ozone resistance. Therefore, ethylene-propylene-diene rubber (EPD)
M) or a rubber material having excellent ozone resistance, such as ethylene-propylene rubber (EPM).
-77508).

[0003] Although the above rubber materials are very excellent in ozone resistance, the paper feed rollers using them alone are inferior in mechanical properties such as abrasion resistance. Therefore, in order to improve the mechanical properties,
EPDM and / or EPM are mixed with a diene rubber such as natural rubber. However,
One EPDM or EPM does not have a double bond in its main chain, while the other diene rubber has two main bonds in its main chain.
Due to the presence of heavy bonds, the vulcanization rates of the two are significantly different. Even if diene rubber is mixed, the mechanical properties do not improve as expected, but rather decrease in many cases. It is.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the mechanical properties of a paper feed roller while maintaining good ozone resistance.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have developed a rubber component containing a copolymer rubber such as EPDM or EPM and a diene rubber, and a rubber component containing a curing agent. As a result of intensive studies on the composition, it is effective to use a specific rubber component having a reactive functional group and a curing agent that reacts with the reactive functional group, and a mixing procedure of each component constituting the rubber composition is effective. Have been found to greatly affect the dispersibility of the components in the composition, and have reached the present invention.

That is, the rubber composition for a paper feed roller of the present invention comprises a copolymer rubber obtained by copolymerizing a monomer containing ethylene and propylene and further containing a diene, and a diene-based rubber. Including a rubber component containing rubber,
The mixing ratio of the copolymer rubber is 100% for the entire rubber component.
A rubber composition that is 10 to 40 parts by weight in parts by weight,
The copolymer rubber has a reactive functional group, and is previously mixed with a curing agent that reacts with the reactive functional group.

The paper feed roller of the present invention is obtained by vulcanizing the above rubber composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition for a paper feeding / conveying roller of the present invention is a composition containing a rubber component and a curing agent. The rubber component contains a copolymer rubber and a diene rubber. First, the rubber composition for the paper feed conveyance roller and a method for producing the same will be described in detail below. Rubber composition for paper feed roller and method for producing the same The rubber composition for paper feed roller of the present invention contains a rubber component containing a copolymer rubber and a diene rubber.

The copolymer rubber is obtained by copolymerizing a monomer containing ethylene and propylene and further containing a diene and having a reactive functional group, that is, a rubber having a reactive functional group. EPDM and / or EPM with reactive functional groups. The reactive functional group is not particularly limited, and examples thereof include functional groups such as an amino group, a bromo group, a chloro group, an isocyanate group, a carboxyl group, a nitrile group, and an epoxy group. Only one of these reactive functional groups may be contained in the copolymer rubber, or two or more thereof may be contained. Among them, the reactive functional group is a carboxyl group, an isocyanate group, a nitrile group, a sulfonyl chloride group (-S
O ₂ Cl) and at least one selected from epoxy groups
A seed is preferable because it has high reactivity and reacts promptly with a curing agent described below.

[0010] Examples of the copolymer rubber include those to which maleic acid or styrene-acrylonitrile is added. Among them, the copolymer rubber is ROYALT
Maleated ethylene-propylene such as AF465, 465A and 372PO (all manufactured by Uniroyal)
Diene rubber (maleated EPDM) is preferred because it has high reactivity and quickly reacts with a curing agent described below.

The diene rubber is not particularly limited,
For example, natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (C
R), hydrogenated acrylonitrile-butadiene rubber (HN
BR) and the like, and any of these may be used alone or as a mixture of two or more. Among them, it is preferable that the diene rubber is a natural rubber because it is inexpensive and has high mechanical strength.

The compounding ratio of the copolymer rubber contained in the rubber component is 10 to 40 parts by weight, preferably 15 to 30 parts by weight, preferably 20 to 2 parts by weight, per 100 parts by weight of the whole rubber component.
More preferably, it is 5 parts by weight. If the blending ratio of the copolymer rubber is too large, it is economically disadvantageous and may have poor mechanical properties. If the proportion of the copolymer rubber is too small, the ozone resistance may be insufficient.

[0013] The rubber composition for a paper feed roller of the present invention contains a curing agent. This curing agent reacts with the reactive functional groups contained in the copolymer rubber. As the curing agent, for example, diaminodiphenyl ether, N-phenyl-
Amine curing agents such as N '-(1,3-dimethylbutyl) -p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, octylated diphenylamine; and N, N'-diethylthiourea Nitrogen-containing hardeners: suberic acid, maleic acid, oxalic acid, malonic acid,
Polycarboxylic acid-based curing agents such as succinic acid; polyol-based curing agents such as ethylene glycol, propylene glycol, and glycerin; and the like. Any one of these can be used alone, or two or more can be used in combination. Is also good.
Among them, it is preferable that the curing agent is an amine-based curing agent because it cures quickly, and it is preferable that the amine-based curing agent is diaminodiphenyl ether because of high reactivity. As the amine-based curing agent, an amine-based antioxidant, a thiourea-based vulcanization accelerator, a polyamine, or the like may be used as it is.

The amine-based curing agent can easily react with reactive functional groups such as bromo group, chloro group, isocyanate group, and carboxyl group in the copolymer rubber. The polycarboxylic acid-based curing agent can easily react with a reactive functional group such as an epoxy group and an amino group. Further, the polyol-based curing agent can easily react with a reactive functional group such as an isocyanate group, an epoxy group, and a sulfonyl chloride group (—SO ₂ Cl).

The mixing ratio of the curing agent in the rubber composition for the paper feeding and conveying roller is not particularly limited, but is preferably 0.5 to 3 parts by weight based on 100 parts by weight of the whole rubber component.
More preferably, it is 2 parts by weight. If the compounding ratio of the curing agent is too large, unreacted curing agent remains in the rubber composition, there is a risk of bloom, and if the compounding ratio of the curing agent is too small, the copolymer rubber is contained in the diene rubber. It may not be finely dispersed, and the mechanical properties of the paper feed roller obtained by vulcanizing the rubber composition may be reduced.

[0016] The rubber composition for the paper feed roller includes, in addition to the copolymer rubber, the diene rubber and the curing agent described above, a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator, a scorch inhibitor, Anti-aging agent, softener, plasticizer, filler (reinforcing agent),
An additive such as a foaming agent may be included as necessary. Examples of the vulcanizing agent include powdered sulfur, precipitated sulfur, insoluble sulfur, peroxide vulcanizing agent, and the like, and any of these may be used alone or in combination of two or more. . Among them, it is preferable that the vulcanizing agent is powdered sulfur because a paper feed roller obtained by vulcanizing the rubber composition is inexpensive and has excellent mechanical properties.

Examples of the vulcanization accelerator include thiurams such as tetramethylthiuram disulfide and tetraethylthiuram disulfide; didithiocarbamate salts such as zinc dibutyldithiocarbamate, zinc diethyldithiocarbamate and tellurium diethyldithiocarbamate;
Thiazoles such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; N-cyclohexyl-2
-Benzothiazolylsulfenamide, N-tert-
Butyl-2-benzothiazolylsulfenamide, N,
Examples thereof include sulfenamides such as N-dicyclohexyl-2-benzothiazolylsulfenamide, and any of these may be used alone or in combination of two or more.

Examples of the vulcanization accelerating aid include metal salts such as zinc white; fatty acids such as stearic acid and oleic acid. Any of these may be used alone or in combination of two or more. You may use it. When a fatty acid is used as a vulcanization accelerator, when a large amount of the fatty acid is used,
Since the friction coefficient of the paper feed roller obtained by vulcanizing the rubber composition may be extremely reduced, the amount of the fatty acid in the rubber composition is 1 part by weight or less based on 100 parts by weight of the rubber component. It is preferred that

Examples of the scorch inhibitor include a phthalic acid-based scorch inhibitor, a sulfenamide-based scorch inhibitor, a benzoic acid-based scorch inhibitor and the like. Mixtures of more than one species may be used. As the filler (reinforcing agent), for example, carbon black, calcium carbonate, clay,
Examples thereof include barium sulfate and diatomaceous earth, and any of these may be used alone or in combination of two or more. If a large amount of carbon black is used as a filler, the paper will be soiled when a paper feed roller obtained by vulcanizing the rubber composition is used. It is preferred that the amount is not more than 10 parts by weight based on parts by weight.

In the rubber composition of the present invention, the copolymer rubber is preliminarily mixed with a curing agent, as will be described in detail below. The method for producing the rubber composition for the paper feed conveyance roller is, for example, such that the copolymer rubber is 10 to 40 parts by weight based on 100 parts by weight of the entire rubber component including the copolymer rubber and the diene rubber. A rubber component preparing step of preparing a copolymer rubber and a diene rubber; a curing agent mixing step of mixing the curing agent with the copolymer rubber to obtain a blend in advance; and mixing the diene rubber with the blend. Mixing a diene rubber.

The rubber component preparing step is a step of preparing a copolymer rubber and a diene rubber contained in the rubber component described above. In particular, the copolymer rubber is prepared so as to be 10 to 40 parts by weight based on 100 parts by weight of the whole rubber component. As described above, it is preferable that the copolymer rubber is prepared to be 15 to 30 parts by weight based on 100 parts by weight of the whole rubber component, and it is more preferable that the copolymer rubber is prepared to be 20 to 25 parts by weight. .

The curing agent mixing step is a step of mixing a curing agent with the copolymer rubber prepared in the rubber component preparing step to obtain a blend in advance. The type of the curing agent and the compounding ratio thereof are as described above. In order to mix (knead) the curing agent with the copolymer rubber, a kneader such as a roll or a kneader is usually used, and the kneading temperature for mixing the curing agent with the copolymer rubber in advance is 50 to 100 ° C. Preferably, the temperature is 60-80 ° C. If the kneading temperature is high, the vulcanization of the copolymer rubber may proceed. In addition, when the kneading temperature is low, the processability in molding the obtained rubber composition may be deteriorated.

The diene rubber mixing step is a step of mixing a diene rubber with the blend obtained in the curing agent mixing step. A kneader such as a kneader or a Banbury mixer is usually used to mix (knead) the diene rubber into the blend. The kneading temperature for mixing the diene rubber is 1
It is preferably from 100 to 150 ° C, and more preferably from 110 to 150 ° C.
Is more preferable. If the kneading temperature is high, the rubber component is significantly deteriorated, which is not preferable. If the kneading temperature is low, the copolymer rubber will not be finely dispersed in the diene-based rubber, and the mechanical properties of the paper feed roller obtained by vulcanizing the rubber composition may be reduced.

In producing the rubber composition for the paper feeding and conveying roller, the above-described additive may be further used. In this case, the additive is further mixed in the curing agent mixing step or the diene rubber mixing step. Alternatively, another process may be newly provided after the diene rubber mixing process to mix the additives. In addition, the kind of the additive and the compounding ratio thereof are as described above.
In particular, when sulfur and a vulcanization accelerator are compounded as additives, they are vulcanized at a high temperature. Therefore, it is preferable that the step of mixing sulfur and the vulcanization accelerator be a separate step.

Paper Feeding and Conveying Roller The paper feeding and conveying roller of the present invention is obtained by vulcanizing the above-described rubber composition for the paper feeding and conveying roller. A known method can be adopted as a method of manufacturing the sheet feeding and conveying roller. For example, a method of forming the sheet feeding and conveying roller while vulcanizing it using an injection molding machine, or a method of manufacturing the rubber. Transfer molding, injection molding,
Vulcanizing can method, electric press method, etc.
There is a method of molding and vulcanizing at 0 ° C. for 5 to 120 minutes at a pressure of 3 to 60 kg / cm ² .

The shape of the paper feed roller is not particularly limited as long as it is cylindrical or columnar. FIG. 1 shows a schematic diagram in which a sheet feeding roller is used as a sheet feeding roller of a copying machine. A shaft 2 is fitted in the center hole of the paper feed roller 1, and a pad 3 is provided to face the paper feed roller 1. When the shaft 2 is rotated around the central axis in the direction of the arrow,
The paper feed roller 1 also rotates in the same direction about the same central axis as the center of rotation, so that the paper 4 near the paper feed roller 1 is entangled and passes through the gap between the paper feed roller 1 and the pad 3. That is, the paper 4 is supplied into the copy machine.

Next, FIG. 2 shows a schematic diagram in which the paper feeding and conveying rollers are used as the conveying rollers of a copying machine. In the same manner as described above, two transport rollers 5 with the shafts 2 mounted thereon are prepared and opposed to each other. When the respective shafts 2 are rotated in the opposite directions, the paper 4 near the transport rollers 5 is entangled. It will pass through the gap between the opposing transport rollers 5,5. The paper feed conveyance roller can be used in various devices having a mechanism for conveying paper. For example, when used for a paper feeding roller, a conveying roller, a paper discharging roller, and the like of an image forming apparatus such as a laser beam printer, an electrostatic copying machine (copier), and a plain paper facsimile machine, it is possible to maintain good ozone resistance. Excellent mechanical properties.

[0028]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to the following Examples. Example 1 The components shown in Example 1 of Table 1 were kneaded according to the following.

The maleated EPDM and the diaminodiphenyl ether as a curing agent were previously mixed at a mixing and kneading temperature shown in Table 2 using a kneader to obtain a maleated EPDM blend. The diene rubber natural rubber, stearic acid and zinc oxide are added to the maleated EPDM blend obtained in the above step, and the resulting mixture is mixed using a kneader at a kneading temperature shown in Table 1 to obtain a diene rubber-containing composition. Obtained.

The sulfur and the vulcanization accelerator are mixed with the diene rubber-containing composition obtained by using a roll,
A rubber composition was obtained. In Comparative Example 3, diaminodiphenyl ether was further mixed to obtain a rubber composition. Press vulcanization of the rubber composition obtained according to the above (temperature: 140 ° C., pressure: 50 kg / cm ² , time:
(30 minutes) to form a rubber roller. This rubber roller is used as a laser beam printer (LaserJet4P).
rus, Hewlett-Packard Company)
20 sheets of 4 size paper (P-4A, manufactured by Fuji Xerox)
The weight of the rubber roller before and after the paper passing test after passing 00 sheets was measured, and the value was converted into the value when 10,000 sheets were passed, and the wear resistance (mechanical properties) was evaluated.

The rubber composition obtained according to the above is press-vulcanized (temperature: 140 ° C., pressure: 50 kg / c)
m ² , time: 30 minutes), molded into a 20 cm square rubber sheet, left for 96 hours in an ozone atmosphere at an ozone concentration of 25 pphm and 40 ° C. according to JIS K-6301, and then expanded by 10% to form a crack. The presence or absence was observed. Those without cracks were evaluated as ○ (good ozone resistance), and those with cracks were evaluated as x (poor ozone resistance).

Table 1 shows the evaluation results. (Examples 2 to 4 and Comparative Examples 1 and 2) Rubbers were prepared in the same manner as in Example 1, except that the types and amounts of the rubber components were as shown in Tables 1 and 2. A composition was prepared. The abrasion resistance (mechanical properties) and ozone resistance of the obtained rubber composition were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0033]

[Table 1]

[0034]

[Table 2]

* 1 See Table 2. * 2 ROYAL TAF made by Uniroyal Chemical
465. * 3 SMR 5CV. * 4 Stearic acid made by Nippon Yushi. * 5 Zinc flower No. 1 manufactured by Hakusui Chemical.

* 6 Powdered sulfur manufactured by Tsurumi Chemical. * 7 Nouchira DM manufactured by Ouchi Shinko Chemical. * 8 Noxeller CZ manufactured by Ouchi Shinko Chemical. As shown in Table 1, when maleated EPDM or styrene acrylonitrile EPDM is previously kneaded with a curing agent,
High wear resistance (mechanical properties) and ozone resistance. On the other hand, when the blending ratio of maleated EPDM is low, ozone resistance is low (Comparative Example 1), and mere EPDM has low wear resistance.

(Effect of Kneading Temperature) In Example 1, the kneading temperature of the curing agent and the rubber component was changed as shown in Table 3, and the kneading temperature was different from the abrasion resistance (mechanical properties) and the ozone resistance. Table 3 shows the results.

[0038]

[Table 3]

As shown in Table 3, if the kneading temperature of the curing agent is too high, the rubber will be burnt and become tattered, and the abrasion resistance (mechanical properties) and ozone resistance cannot be measured. Also, if the kneading temperature of the curing agent is too low, it will not be a normal sample because the curing agent cannot be mixed and dispersed,
Abrasion resistance (mechanical properties) and ozone resistance cannot be measured.

As shown in Table 3, if the kneading temperature of the rubber component is too low, sufficient physical properties cannot be obtained in terms of abrasion resistance.

[0041]

According to the rubber composition for a paper feed roller of the present invention, the copolymer rubber contained in the composition has a reactive functional group and is previously mixed with a curing agent which reacts with the reactive functional group. The copolymer rubber is finely dispersed in the diene rubber while maintaining good ozone resistance, thereby improving the mechanical properties of the paper feed roller. Can be.

The paper feed roller of the present invention is obtained by vulcanizing this rubber composition and has excellent mechanical properties while maintaining good ozone resistance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram in which a paper feed roller of the present invention is used as a paper feed roller of a copying machine.

FIG. 2 is a schematic diagram in which a sheet feeding and conveying roller of the present invention is used as a conveying roller of a copying machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper feed roller 2 Shaft 3 Pad 4 Paper 5 Transport roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI C08L 23:16) (58) Investigated field (Int.Cl. ⁷ , DB name) B65H 5/06 B65H 3/06 C08L 9 / 00 C08L 23/16 C08K 5/18

Claims (4)

(57) [Claims] 1. A rubber composition comprising a copolymer rubber obtained by copolymerizing a monomer containing ethylene and propylene and further containing a diene, and a rubber component containing a diene rubber. The compounding ratio of the united rubber is 1 for the entire rubber component.
A rubber composition that is 10 to 40 parts by weight in 00 parts by weight, wherein the copolymer rubber has a reactive functional group and is previously mixed with a curing agent that reacts with the reactive functional group. A rubber composition for a paper feed roller, characterized by the following. 2. The rubber composition according to claim 1, wherein said copolymer is maleated ethylene-propylene-diene rubber. 3. The rubber composition according to claim 1, wherein the curing agent is diaminodiphenyl ether. 4. A paper feed roller formed by vulcanizing the rubber composition according to claim 1.