JP3439853B2 - Rubber composition - 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, and more specifically, it is suitable for members such as rollers, blades and belts used in electrophotographic devices such as copying machines and printers and electrostatic recording devices. The present invention relates to a rubber composition used in.

[0002]

2. Description of the Related Art Conventionally, a large number of members made of a rubber composition have been used in electrophotographic devices such as copying machines and printers, and electrostatic recording devices.
It plays various roles such as transfer, toner layer formation, cleaning, fixing, paper feeding, and paper transportation. It is said that a rubber member having a low hardness is desirable in terms of performance as a rubber member used in these processes. The low-hardness product is desirable because the design allowable range in each process is widened. For example, since the developing roller hits the photosensitive member well, the toner can be easily transported.

For example, a foam is used for a transfer roller used in a transfer process for transferring an electrostatic latent image on a photoconductor onto recording paper. However, in a charging roller to which a high voltage is applied and a developing roller that forms toner on a photosensitive member, it is difficult to use a foam in terms of durability, image fineness and reliability. In addition, it is difficult for the foam to meet the requirement in terms of abrasion resistance even in the paper feed roller that conveys the recording paper.

In order to realize a low hardness member instead of a foamed material, there is a method of blending a plasticizer, an extending oil and the like into the composition to reduce the relative polymer content and thereby reduce the hardness. However, low molecular weight substances such as plasticizers and extender oils have the problem of bleeding out, which contaminates the photoconductor and recording paper and is therefore not necessarily suitable as a member of the electrophotographic process. In order to solve the problem of contamination due to bleed-out, a method has also been proposed in which only the outer layer that directly contacts the photoconductor or recording paper is covered with a non-contaminating resin or rubber, but the manufacturing process is complicated. In addition, it is difficult to provide an inexpensive electrophotographic rubber material.

When the present inventors use it as a rubber member in electrophotographic devices such as copying machines and printers, electrostatic recording devices, etc., they are EPs as low hardness rubber compositions which solve the above problems.
A rubber composition composed of DM and acrylic rubber has been proposed. However, the inventors have found from subsequent studies that for some applications the composition is still problematic in durability. For example, the paper feed roller is required to have durability, abrasion resistance and surface stability in the process of conveying a huge number of recording papers, but the above composition has not completely satisfied the required performance.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and when used as a rubber member in an electrophotographic apparatus such as a copying machine or a printer, an electrostatic recording apparatus, or the like, An object of the present invention is to provide a rubber composition which has a low hardness, solves the problem of bleed-out, and is excellent in durability.

[0007]

Means for Solving the Problems As a result of intensive investigations, the present inventors have found that EPDM95-
A rubber composition comprising 5 parts by weight of acrylic rubber and 5 to 95 parts by weight of acrylic rubber, wherein 1 to 30 parts by weight of butadiene rubber is added to 100 parts by weight of the rubber composition. Thus, as a filler, silica is included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the rubber composition of the EPDM and acrylic rubber, and a silane coupling agent is added as an additive as described in claim 3. , The EPD
The present invention has been found to achieve the above object when 0.1 to 5 parts by weight is contained with respect to 100 parts by weight of a rubber composition of M and acrylic rubber.

[0008]

The present invention will be described in more detail below. In the present invention, EPDM, acrylic rubber, and butadiene rubber are used as a blend, but when EPDM and acrylic rubber are combined to 100 parts by weight, EPDM is 5 to 95.
It is 10 parts by weight, preferably 10 parts by weight to 90 parts by weight, and more preferably 20 parts by weight to 80 parts by weight. EPDM
If it is 5 parts by weight or less, the durability against ultraviolet rays is not sufficient, and if it is more than 95 parts by weight, the hardness is too high.

The acrylic rubber is 5 to 95 parts by weight, preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight. Acrylic rubber is 5
If it is less than 95 parts by weight, it is not possible to exhibit a sufficiently low hardness because it is close to the characteristics of EPDM, and if it is more than 95 parts by weight, the processing becomes very difficult due to the tackiness of the acrylic rubber.

The butadiene rubber is 1 to 30 parts by weight, preferably 2 to 28 parts by weight, and more preferably 3 parts by weight, based on 100 parts by weight of the rubber composition of EPDM and acrylic rubber. -25 parts by weight. If the amount of butadiene rubber is less than 1 part by weight, sufficient durability and abrasion resistance cannot be exhibited, and if it is more than 30 parts by weight, the hardness becomes too high. In the present invention,
When used as an electrophotographic process member, a JIS-A hardness of 45 is defined as a definition of a low-hardness composition having a high effect.
° or less.

The EPDM used in the present invention is a terpolymer composed of ethylene, propylene and a third component. The third component is not particularly limited, but dicyclopentadiene, ethylidene norbornene, 1 , 4
-Hexadiene and the like are preferably used. The proportions of ethylene, propylene and the third component are not particularly limited, but the ethylene content is 5 to 95% by weight, the propylene content is 5 to 95% by weight, and the third component content is Is preferably 0 to 50 in terms of iodine value. It is also possible to mix and use two or more kinds of EPDM having different iodine values. The EPDM used in the present invention preferably has a weight average molecular weight of 250,000 or more, more preferably 300,000 or more.

The EPDM used in the present invention may be oil-extended for the purpose of improving workability. As the oil-extending material, petroleum-based fractionated oil, pine resin, coal tar products, natural fats and oils and their derivatives, synthetic organic compounds and the like are preferably used, but petroleum-based paraffin is preferable because it does not easily contaminate the photosensitive material. Oil is most preferred. The weight average molecular weight of this paraffin oil is preferably 500 or more, more preferably 800 or more. The amount of the oil-extended material added is preferably 5 to 150 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of EPDM.

Regarding the acrylic rubber used in the present invention, a monomer unit whose main chain is represented by Chemical Formula 1 and / or Chemical Formula 2, for example, methyl acrylate, ethyl acrylate, butyl acrylate and the like in Chemical Formula 1, methoxyethyl acrylate in Chemical Formula 2, Examples thereof include ethoxyethyl acrylate, and the third component of the copolymer, which is deposited in the acrylic rubber for crosslinking, is an active chlorine-containing monomer, a carboxyl group-containing monomer, or an epoxy group-containing monomer. There is no particular limitation on the ones, such as 2-chloroethyl vinyl ether, vinyl chloroacetate, etc., but they may be used alone or in combination and can be used freely.

[0014]

[Chemical 1]

[Chemical 2]

The butadiene rubber used in the present invention may be any commercially available one, but one having a cis 1,4 content of 90% or more is preferably used.

In the present invention, silica can be used as a filler or a reinforcing agent. The type of silica is not particularly limited, and those obtained by the wet method, those obtained by the dry method, those obtained by surface treatment and the like are preferably used. 1 to 50 parts by weight of silica can be added to 100 parts by weight of the rubber composition of EPDM and acrylic rubber, and 2 to 40 parts by weight is more preferable. If the amount of silica is less than 1 part by weight, a sufficient auxiliary effect cannot be obtained for the rubber composition, and 5
If it is more than 0 parts by weight, the hardness of the composition becomes too high due to the filling effect.

In the present invention, a silane coupling agent can be added as an additive in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber composition of EPDM and acrylic rubber. It is more preferably 0.2 to 4.5 parts by weight.
When the amount of the silane coupling agent is less than 0.1 part by weight, a sufficient reinforcing effect cannot be obtained, and when it is more than 5 parts by weight, the crosslinking rate becomes slow and the cost increases, which is not preferable. Although there are various types of silane coupling agents, one of the reactive groups is an alkoxy group such as a methoxy group or an ethoxy group that bonds to an inorganic material, and the other reactive group is a vinyl group that bonds to an organic material. , Epoxy group, amino group, methacryl group, mercapto group and the like are preferably used.

The rubber composition of the present invention may contain a cross-linking agent and a vulcanizing agent in order to cross-link into a rubber-like substance,
There are no particular restrictions on the crosslinking system such as organic peroxide, sulfur crosslinking, and metal salt crosslinking. In any case, a crosslinking aid, a crosslinking accelerator,
A crosslinking accelerator, a crosslinking retarder, etc. can be used. In addition to the above, reinforcing agents, fillers, peptizers, foaming agents, plasticizers, softeners, which are generally used as rubber compounding agents,
A tackifier, a dispersant, a release agent, a filler, a colorant and the like can be added.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples in which the sheet feeding roller is required to have low hardness and high durability, but the present invention is not limited to these Examples. Also, in the field of industrial application, not only in the field of electronic equipment, but also in the fields of automobiles, construction, utilizing low viscosity and high durability.
It goes without saying that it can be applied to a wide range of fields such as civil engineering.

[Example 1] For 100 parts by weight of a rubber composition consisting of 45 parts by weight of EPDM (EP98A manufactured by Japan Synthetic Rubber Co., Ltd.) and 55 parts by weight of acrylic rubber (AREX210 manufactured by Japan Synthetic Rubber Co., Ltd.), butadiene 10 parts by weight of rubber (BR01 manufactured by Japan Synthetic Rubber Co., Ltd.), 2 parts by weight of silane coupling agent (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.), 10 parts by weight of silica, 5 parts by weight of titanium oxide, 2 parts by weight of dicumyl peroxide. Parts are added and mixed by a roll mill,
A test piece was produced by molding in a mold preheated to 160 ° C. under a pressure of 100 kg / cm ² for 40 minutes. The roll processability was good, and the JIS-A hardness was 40 ° C. The ultraviolet resistance was evaluated by performing an ozone deterioration test according to JIS-A6301 and combining three grades from A to C in terms of the number of cracks and 1 to 5 grades in terms of the crack size and depth from the smallest. This example was A-2. For the abrasion resistance to paper, a paper feed roller was produced using this composition, and Laser Jet-manufactured by Hewlett-Packard Co.
It was mounted on a 3 · Si type printer and a paper passing test of 20,000 sheets was conducted. In this example, the roller surface did not change significantly after the test.

[Second Embodiment] In the first embodiment, the EPD
Test pieces were prepared under the same conditions as in Example 1 except that the compounding parts of M, acrylic rubber, and butadiene rubber were changed as shown in Table 1.

[Comparative Examples 1 to 3] In Comparative Example 1, as shown in Table 1, a combination of EPDM and acrylic rubber alone was used, and a compounding formulation was used in which butadiene rubber and a silane coupling agent were not used. In the case of No. 3, except for the case where the compounding ratio of EPDM and acrylic rubber was out of the scope of the claims of the present invention, both test pieces were produced by the same method as in Example 1. Table 1 shows the compounding formulations of the rubber compositions and the results thereof in Examples and Comparative Examples.

[0023]

[Table 1]

[0024]

As described above, as a result of the present invention, the ethylene-propylene-diene terpolymer (E
PDM) 95 to 5 parts by weight and acrylic rubber 5 to 95 parts by weight, wherein the rubber composition 100
A rubber composition containing 1 part by weight to 30 parts by weight of butadiene rubber with respect to parts by weight, and silica as the filler as described in claim 2, wherein silica is the rubber composition of EPDM and acrylic rubber. 1 to 50 parts by weight with respect to parts by weight. Furthermore, as described in claim 3, a silane coupling agent as an additive is added in an amount of 0.1 to 5 with respect to 100 parts by weight of the rubber composition of the EPDM and acrylic rubber.
By using a rubber composition characterized by being included in parts by weight, durability, which is a drawback when used as a rubber member in the above-described conventional electrophotographic devices such as copying machines and printers, electrostatic recording devices, etc. In particular, it is possible to greatly improve the durability, particularly the durability in the process of conveying a huge number of recording sheets such as a sheet feed roller, the abrasion resistance, the surface stability and the like.

Claims (3)

(57) [Claims] 1. A rubber composition comprising 95 parts by weight to 5 parts by weight of an ethylene-propylene-diene three-dimensional copolymer (EPDM) and 5 parts by weight to 95 parts by weight of an acrylic rubber, and 100 parts by weight of the rubber composition. On the other hand, 1 to 30 parts by weight of butadiene rubber is contained in the rubber composition. 2. The rubber composition according to claim 1, wherein silica is contained as a filler in an amount of 1 to 50 parts by weight based on 100 parts by weight of the rubber composition rubber of EPDM and acrylic rubber. . 3. The silane coupling agent as an additive is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber composition of EPDM and acrylic rubber. Rubber composition.