JP4843085B2 - OA roller and coating agent for OA roller - Google Patents

Description

  The present invention includes a coating layer on the outer peripheral surface of a metal roller body. For example, an OA roller used as a driving roller in an OA device such as an electrostatic copying machine, and an OA for forming the coating layer of the OA roller. The present invention relates to a roller coating agent.

  As an OA roller such as a driving roller used for rotationally driving a paper feed belt, a transfer belt, an intermediate transfer belt, etc. in an OA device such as an electrostatic copying machine, a laser printer, a plain paper facsimile machine, and a complex machine thereof. In some cases, the outer peripheral surface of a metal roller body is coated with a coating layer to prevent slippage with respect to a belt or the like, or the surface of the coating layer is roughened (for example, a patent) References 1-3).

However, with the recent increase in printing speed in the electrostatic copying machine or the like, the conventional OA roller cannot effectively prevent slipping with the belt over a long period of time. There has been a problem that slipping occurs in a short period of time.
This is because the driving roller or the like repeatedly contacts with the belt or the like over a long period of time, so that the roughened outer peripheral surface is worn and the frictional force is reduced. It may be lost from the outer peripheral surface.

  In addition to the problem of slipping, for example, the coating layer may be partially deformed or stuck to a belt or the like when the electrostatic copying machine is stopped under a usage environment such as high temperature or high humidity. There is also a tendency that the coated layer is peeled off from the outer peripheral surface of the roller body, and the peeled pieces enter other parts such as an electrostatic copying machine to affect the formed image.

Japanese Patent Laid-Open No. 10-236627 Utility Model Registration No. 3000760 JP 2002-326733 A

  The object of the present invention is that the coating layer formed on the outer peripheral surface of the metal roller body is not worn or deformed in a short period of time, or is not attached to or peeled off from a belt or the like. An object of the present invention is to provide an OA roller capable of maintaining good characteristics, and an OA roller coating agent suitable for forming a coating layer of the OA roller.

  In order to solve the above problems, the inventor adds a crosslinking agent for the binder resin to a coating agent containing a curable binder resin such as urethane resin to form a coating layer, thereby increasing the crosslinking density of the binder resin after curing. To prevent the coating layer from being partially deformed or sticking to a belt, etc., and by adding a pigment to the coating agent, the shrinkage of the film during curing of the binder resin is alleviated and cured. It was studied to prevent peeling by increasing the adhesion of the subsequent coating layer to the outer peripheral surface of the metal roller body.

However, depending on the type of cross-linking agent, it is not possible to introduce a good cross-linking structure into the coating layer, especially when the coating layer is partially deformed or stuck to a belt, etc. under high temperature, high humidity environment, etc. There has been a problem that peeling from the outer peripheral surface of the roller body cannot be prevented.
In addition, when the content of the crosslinking agent is too large, the coating layer becomes hard and the surface friction coefficient decreases and slippage with the belt tends to occur. When the content of the pigment is too large, the coating layer becomes brittle. On the other hand, there was a problem that it was easy to peel from the outer peripheral surface of the roller body.

Then, as a result of further examination on the type and content ratio of the crosslinking agent and the range of the content ratio of the pigment, the present invention has been found.
That is, according to the present invention, a binder resin having a curing property that is cured by a reaction with an amino resin as a crosslinking agent on the outer peripheral surface of a metal roller body, and 25 parts by mass or more and 120 parts by mass per 100 parts by mass of the binder resin. OA, wherein a coating layer formed by curing a binder resin after applying a coating agent containing 15 parts by weight or less of the pigment and 15 parts by weight or more and 55 parts by weight or less of the amino resin is provided. Laura.

Further, the present invention is for forming the coating layer, and has a curable binder resin, a pigment of 25 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the binder resin, and 15 parts by mass. As described above, the coating agent for an OA roller includes 55 parts by mass or less of an amino resin as a crosslinking agent for the binder resin.
The binder resin is preferably a water-based urethane resin. Since the coating agent containing the water-based urethane resin can be formed using water as a solvent, the load on the environment can be reduced.

The pigment preferably contains at least an extender pigment. The extender pigment is excellent in preventing the film from shrinking when the binder resin is cured.
The pigment preferably contains a pigment having at least needle-like protrusions. The needle-like protrusions of the pigment protrude from the surface of the coating layer as micro protrusions, improve the friction coefficient of the OA roller by the scratching effect with the belt, and maintain the high friction coefficient over a long period of time. Is excellent.

  According to the present invention, the coating layer formed on the outer peripheral surface of the metal roller body does not wear or deform in a short period of time, or does not stick to or peel off from a belt or the like. An OA roller capable of maintaining good characteristics and a coating agent for an OA roller suitable for forming a coating layer of the OA roller can be provided.

It is a figure explaining the outline of the apparatus used in order to measure the friction coefficient (micro | micron | mu) with respect to the belt of the surface of the coating layer in the OA roller of this invention.

  The present invention provides a binder resin having curability on the outer peripheral surface of a metal roller body, 25 parts by mass or more and 120 parts by mass or less of pigment, and 15 parts by mass or more and 55 parts by mass per 100 parts by mass of the binder resin. An OA roller characterized in that a coating layer formed by applying a coating agent containing an amino resin as a crosslinking agent for the binder resin below the binder resin and then curing and crosslinking reaction of the binder resin is provided. is there.

Further, the present invention is a coating agent for forming the coating layer, a curable binder resin, a pigment of 25 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the binder resin, and 15 parts by mass. And an amino resin as a crosslinking agent for the binder resin in an amount of 55 parts by mass or more and 55 parts by mass or less.
As the binder resin, various resins that are curable and capable of increasing the crosslinking density by reacting with an amino resin as a crosslinking agent can be used, and an aqueous urethane resin is particularly preferable. Since the coating agent containing the water-based urethane resin can be formed using water as a solvent, the load on the environment can be reduced.

  Examples of the water-based urethane resin include, but are not limited to, Permarin (registered trademark) UA-300, UA-310, UA-368, and polyether-based products manufactured by Sanyo Chemical Industries, which are water-based emulsions of polycarbonate-based polyurethane resins. Permarin UA-50, which is an aqueous solution of polyurethane resin, Permarin UA-150, UC-20, which is an emulsion of polyether polyurethane resin, and Daiichi Kogyo Seiyaku, which is also an emulsion of polyether polyurethane resin ( 1 type, or 2 or more types, such as Superflex (trademark) E-4000 made by Corporation | KK, are mentioned.

Examples of the amino resin include various amino resins that can function as a crosslinking agent for the aqueous urethane resin, such as melamine resin, urea resin, and guanamine resin.
Examples of the amino resin include, but are not limited to, Cymel (registered trademark) 323, 325, 327, 328, and 385 manufactured by Cytec, which is a solution of a methylated high iminomelamine resin, and a solution of a partially methylated melamine resin. Cymel 370, 373, 3749 made by the same company, Yuban (registered trademark) 120 made by Mitsui Chemicals, which is a solution of n-butylated melamine resin, or Hitachi Chemical Co., Ltd., which is a solution of methyl etherified melamine resin 1 type or 2 types or more, such as Melan (registered trademark) 552.

The content ratio of the amino resin needs to be 15 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the binder resin.
If the content ratio is less than the above range, the crosslinking density of the binder resin is increased by including the amino resin, and the coating layer is partially deformed or stuck to a belt or the like, particularly in a high temperature and high humidity environment. The effect of preventing the adhered coating layer from peeling off from the outer peripheral surface of the roller body cannot be obtained.

On the other hand, when the content ratio exceeds the above range, the crosslink density of the binder resin becomes too high and the coating layer becomes too hard, so that the friction coefficient of the surface is lowered and slipping with the belt or the like is likely to occur.
In any of the above cases, the adhesion of the coating layer to the outer peripheral surface of the roller body also tends to slightly decrease.

In consideration of forming a coating layer having excellent adhesion to the outer peripheral surface of the metal roller body while more effectively suppressing the occurrence of these problems, the amino resin content is Even within the range, it is preferably 25 parts by mass or more and preferably 45 parts by mass or less per 100 parts by mass of the binder resin.
In addition, when using the emulsion and aqueous solution demonstrated previously as binder resin and using the solution demonstrated previously as amino resin, the content rate of the said amino resin is solid content (binder resin) 100 mass of the said emulsion or aqueous solution. It is a mass part of solid content (amino resin) in the solution per part.

As the pigment, an extender pigment excellent in the effect of preventing the film from shrinking when the binder resin described above is cured is preferable.
Examples of the extender pigment include clay such as kaolin, or one or more of precipitated barium sulfate, calcium carbonate, aluminum hydroxide, magnesium carbonate, talc, mica, and the like.

The content ratio of the pigment needs to be 25 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the binder resin.
If the content ratio is less than the above range, the pigment is contained to reduce the shrinkage of the film when the binder resin is cured, and the adhesion of the cured coating layer to the outer peripheral surface of the metal roller main body is increased and peeled off. The effect of preventing is not obtained.

Moreover, when a content rate exceeds the said range, a coating layer becomes weak and it becomes easy to peel from the outer peripheral surface of a roller main body on the contrary.
In consideration of more effectively preventing these problems from occurring and forming a coating layer having excellent adhesion to the outer peripheral surface of the metal roller body, the pigment content is within the above range. However, it is preferably 45 parts by mass or more and preferably 100 parts by mass or less per 100 parts by mass of the binder resin.

A pigment having a needle-like protrusion is also preferable as the pigment. Among them, a pigment having a three-dimensional shape in which two or more needle-like protrusions project radially from the center, for example, a so-called tetrapic pigment in which four needle-like protrusions project from the center at four angles at the same angle is preferable. .
Examples of the pigment include zinc oxide, magnesium oxide, aluminum borate, silicon carbide, silicon nitride, potassium titanate, basic magnesium sulfate, calcium sulfate, calcium sodium phosphate, magnesium borate, calcium carbonate, titanium diboride, and gypsum. , One or more of alumina, chrysotile, sepiolite, zonotolite and the like. It may also be a mixture of star sand from Okinawa Prefecture.

Among them, the zinc oxide whisker exhibiting the tetrapic shape is preferable.
In the pigment, since at least one of two or more protrusions is embedded in the coating layer and exhibits an anchor effect, the pigment can be prevented from falling off due to belt irritation or wear, and the remaining protrusions are microscopic from the surface of the coating layer. It functions as a protrusion that improves the friction coefficient of the OA roller by the effect of scratching with the belt and maintains the high friction coefficient over a long period of time. Therefore, it is possible to maintain good characteristics of the OA roller for a longer period.

However, the entire pigment may have a single needle shape.
In addition, when using the emulsion and aqueous solution demonstrated previously as binder resin, the content rate of the said extender pigment, the pigment which has a needle-shaped protrusion, etc. is solid content (binder resin) per 100 mass parts in the said emulsion or aqueous solution. It is the mass part of the pigment.
As the pigment, a plurality of types of pigments having different functions such as the extender pigment and the pigment having needle-like protrusions may be used in combination. In that case, the good characteristics of the OA roller can be maintained for a longer period due to the synergistic effect of the functions of the pigments. When using together, the content rate of a pigment needs the mass part per 100 mass parts of said solid content of the sum total of two or more pigments used together within the range prescribed | regulated by this invention.

In addition to the above-described components, the coating agent may further contain various conventionally known additives such as an antifoaming agent, a dispersion stabilizer, and a surface tension adjusting agent in an arbitrary ratio.
As described above, the coating agent is preferably an aqueous system using water as a solvent in order to reduce the load on the environment.
For example, when using a binder resin that is supplied in the state of an aqueous emulsion or aqueous solution as described above, a pigment and an amino resin are added to the emulsion or aqueous solution so as to have the predetermined content ratio. The aqueous coating agent can be obtained by adding other additives as necessary.

Further, if necessary, the viscosity of the coating agent may be adjusted by adding water or a mixed solvent of water and a water-soluble organic solvent.
The coating agent is applied to the outer peripheral surface of a cylindrical or columnar roller body made of a metal such as aluminum, copper, brass, stainless steel, etc. by any application method such as a spray coating method, and then dried to form water or the like. The solvent is removed and further heated to cause the binder resin to undergo a curing reaction, and a coating reaction is formed by the action of an amino resin as a crosslinking agent to form an OA roller.

The friction coefficient μ of the surface of the OA roller with respect to the belt to be combined is preferably 0.3 or more, particularly 0.6 or more. If the friction coefficient μ is less than the above range, slippage between the belt and the belt tends to occur, and the belt may not be driven satisfactorily.
In the present invention, the friction coefficient μ is expressed by a value measured by a measuring method based on Euler's belt type using the apparatus shown in FIG.

As described above, the OA roller 3 in which the coating layer 2 is formed on the outer peripheral surface of the metal roller main body 1 is shown in the drawing with the central axis 4 of the roller main body 1 oriented in the horizontal direction. It is held rotatably in the direction indicated by the arrow. A load meter 5 is disposed in the vicinity of the OA roller 3 while maintaining a constant distance from the central shaft 4 of the OA roller 3.
Next, the other end of the belt 7 having a weight 6 with a mass W (g) attached to one end is connected to the load meter 5, and one end on the weight 6 side of the belt 7 is hung below the OA roller 3. In a state of being lowered, the belt 7 is brought into contact with the surface of the coating layer 2 of the OA roller 3 over a range of a central angle θ (°) centered on the central axis 4.

Then, the load F (g) generated when the OA roller 3 is rotated at a constant speed in the direction indicated by the two-dot chain line arrow is measured by the load meter 5, and the load F (g) and the mass of the weight 6 are measured. From W (g) and center angle θ (°), equation (1):
μ = (1 / θ) ln (F / W) (1)
To obtain the friction coefficient μ.

The coating thickness of the coating agent that forms the coating layer is preferably 20 μm or more, and preferably 100 μm or less.
If the coating thickness is less than the above range, a coating layer having a uniform thickness may not be formed.
Further, when the coating thickness exceeds the above range, sagging or the like may occur and the appearance of the coating layer may be deteriorated, and workability such as drying may be deteriorated.

  The OA roller of the present invention is for rotating and driving a paper feed belt, a transfer belt, an intermediate transfer belt, etc. in OA equipment such as an electrostatic copying machine, a laser printer, a plain paper facsimile machine, and a complex machine thereof. It can be suitably used as a drive roller or the like.

In the following examples and comparative examples, the preparation of coating agents, the production of rollers for OA, and the tests were performed in an environment of 23 ± 5 ° C. and relative humidity of 55 ± 5%, unless otherwise specified.
<Example 1>
The above-mentioned Permarine UA-300 manufactured by Sanyo Chemical Industries, Ltd. [Aqueous emulsion of polycarbonate-based polyurethane resin, solid content concentration 38% by mass] is also added to Cymel 327 [Methylated high iminomelamine] manufactured by Cytec. An isobutanol solution of resin, solid concentration of 88 to 92% by mass] and clay [hydrous kaolin-based, ASP-170 manufactured by BASF] were blended to prepare a coating agent.

The content of the clay is 65 parts by mass per 100 parts by mass of the polycarbonate-based polyurethane resin (solid content of Permarin UA-300) as the binder resin in the coating agent, and the methylated high iminomelamine resin (solid content of Cymel 327). ) Content was 36 parts by mass.
The coating agent is applied to the outer peripheral surface of an aluminum (A6063) roller body having an outer diameter of 24φ and a length of 22.6 mm by a spray coating method, left to stand at room temperature for about 30 minutes, and then dried. And 10 minutes of preliminary drying, and then heated at 140 ° C. for 15 minutes to cure and crosslink the binder resin to form a coating layer, thereby producing an OA roller.

<Examples 2-5, Comparative Examples 1-3>
The content ratio of the clay per 10 parts by mass of the polycarbonate-based polyurethane resin as the binder resin is 10 parts by mass (Comparative Example 1), 20 parts by mass (Comparative Example 2), 25 parts by mass (Example 2), and 45 parts by mass. (Example 3), 100 parts by weight (Example 4), 120 parts by weight (Example 5), 150 parts by weight (Comparative Example 3) except that the coating agent was prepared in the same manner as in Example 1, An OA roller was produced.

<Examples 6 to 9, Comparative Examples 4 and 5>
The content ratio of the methylated high iminomelamine resin per 100 parts by mass of the polycarbonate-based polyurethane resin as the binder resin is 10 parts by mass (Comparative Example 4), 15 parts by mass (Example 6), and 25 parts by mass (Example 7). , 45 parts by mass (Example 8), 55 parts by mass (Example 9), and 60 parts by mass (Comparative Example 5). .

<Example 10>
A coating agent was prepared in the same manner as in Example 1 except that Cymel 370 (isobutanol solution of partially methylated melamine resin, solid concentration: 86 to 90% by mass) manufactured by Cytec was used instead of Cymel 327. A OA roller was produced.
The content ratio of the partially methylated melamine resin (solid content of Cymel 370) per 100 mass parts of the polycarbonate-based polyurethane resin (solid content of Permarin UA-300) as the binder resin in the coating agent was 36 parts by mass.

<Comparative Example 6>
In place of Cymel 327, Carbodilite (registered trademark) E-02 manufactured by Nisshinbo Chemical Co., Ltd. (aqueous emulsion of polycarbodiimide, solid concentration 40% by mass), which is a different type of crosslinking agent from amino resin, was used. Prepared a coating agent in the same manner as in Example 1 to produce an OA roller.

In the coating agent, the content ratio of polycarbodiimide (solid content of carbodilite E-02) per 100 parts by mass of polycarbonate-based polyurethane resin (solid content of Permarin UA-300) as a binder resin was 36 parts by mass.
<Comparative Example 7>
In place of Cymel 327, Elastolon (registered trademark) BN69 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (solution of blocked isocyanate compound, solid content concentration: 40% by mass), which is a different type of crosslinking agent from amino resin, was used. Prepared a coating agent in the same manner as in Example 1 to produce an OA roller.

In the coating agent, the content ratio of the block isocyanate compound (solid content of Elastron BN69) per 100 parts by mass of the polycarbonate-based polyurethane resin (solid content of Permarin UA-300) as the binder resin was 36 parts by mass.
<High temperature and high humidity test>
The belt is wound around the outer peripheral surface of the OA roller in a state where the polyimide belt is brought into direct contact with the surface of the coating layer constituting the outer peripheral surface of the OA roller manufactured in each of the above Examples and Comparative Examples. After standing for 7 days in a high temperature and high humidity environment of 60 ° C. and 80% relative humidity, the state was observed, and the coating layer was evaluated according to the following criteria.

○: The coating layer was not partially deformed or adhered to the belt or the like.
X: The coating layer was partially deformed or adhered to a belt or the like.
<Adhesion test>
The adhesiveness of the coating layer in the OA roller produced in each of the above Examples and Comparative Examples was determined according to Japanese Industrial Standard JIS K5600-5-6: 1999 “Paint General Test Method—Part 5: Mechanical Properties of Coating Film—No. The test results were evaluated in accordance with the test method described in “Section 6: Adhesion (Crosscut Method)”. That is, the test results were classified into 6 levels according to Table 1 of JIS K5600-5-6, and classification 0-2 was judged as good adhesion and classification 3-5 was judged as poor adhesion.

<Friction coefficient measurement>
From the results of measuring the friction coefficient of the surface of the coating layer with respect to the polyimide belt in the OA rollers produced in the respective Examples and Comparative Examples using the apparatus shown in FIG. ).
The above results are shown in Tables 1 to 3.

From the results of Examples 1 to 10 in Tables 1 to 3 and Comparative Examples 6 and 7 in Table 3, when an amino resin was used as the crosslinking agent, a good cross-linked structure was introduced into the coating layer, and the It has been found that the coating layer can be prevented from being partially deformed or stuck to a belt or the like in a wet environment, and from being peeled off from the outer peripheral surface of the roller body.
Moreover, from the results of Examples 1 to 5 and Comparative Examples 1 to 3 in Table 1, the content ratio of the clay as the pigment needs to be 25 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the binder resin. It has been found that the content is preferably 45 parts by mass or more and 100 parts by mass or less.

Furthermore, from the results of Examples 1 and 6 to 9 in Table 2, the content ratio of the amino resin as a crosslinking agent needs to be 15 parts by mass or more and 55 parts by mass or less, particularly 25 parts by mass per 100 parts by mass of the binder resin. It was found that the amount is preferably not less than 45 parts and not more than 45 parts by mass.
<Examples 11 to 13>
Instead of clay as an extender (above ASP-170), zinc oxide whisker exhibiting a tetrapic shape [Panatetra (registered trademark) manufactured by Panasonic Corporation] is used as a binder resin. A coating agent was prepared in the same manner as in Example 1 except that 25 parts by mass (Example 11), 65 parts by mass (Example 12), and 100 parts by mass (Example 13) were contained per part. An OA roller was produced.

<Example 14>
A coating agent was prepared in the same manner as in Example 1 except that clay as an extender (above ASP-170) and a zinc oxide whisker exhibiting a tetrapic shape (above Panatetra) were used in combination. A roller was produced. The content ratio of both pigments per 100 parts by mass of the polycarbonate-based polyurethane resin as the binder resin was 30 parts by mass for clay, 35 parts by mass for zinc oxide whisker, and 65 parts by mass in total.

<Example 15>
Coating is carried out in the same manner as in Example 14 except that the content ratio of both pigments per 100 parts by mass of the polycarbonate-based polyurethane resin as the binder resin is 65 parts by mass of clay, 30 parts by mass of zinc oxide whisker, and 95 parts by mass in total. An agent was prepared to produce an OA roller.

<Comparative Example 8>
Coating was carried out in the same manner as in Example 14 except that the content ratio of both pigments per 100 parts by mass of the polycarbonate-based polyurethane resin as the binder resin was 65 parts by mass of clay, 65 parts by mass of zinc oxide whisker, and 130 parts by mass in total. An agent was prepared to produce an OA roller.

  The characteristics described above were evaluated for the OA rollers produced in the examples and comparative examples. The results are shown in Table 4.

  From the results of Examples 11 to 15 in Table 4, it was found that the friction coefficient of the OA roller can be significantly improved by including a pigment having needle-like protrusions. Further, from the results of Examples 11 to 15 and Comparative Example 8, the pigment content (total amount) is used in combination with an extender such as clay and a system in which a pigment having needle-like protrusions is used alone. In any of the systems, it was found that the amount must be 25 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the binder resin.

F Load W Mass θ Center angle 1 Roller body 2 Coating layer 3 OA roller 4 Center shaft 5 Load meter 6 Weight 7 Belt

Claims (5)

  On the outer peripheral surface of the roller body made of metal, curable binder resin, 25 parts by mass or more and 120 parts by mass or less of pigment, and 15 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the binder resin. An OA roller having a coating layer formed by applying a coating agent containing an amino resin as a crosslinking agent for the binder resin and then curing and crosslinking the binder resin.   The OA roller according to claim 1, wherein the binder resin is a water-based urethane resin.   The OA roller according to claim 1, wherein the pigment contains at least an extender pigment.   The OA roller according to any one of claims 1 to 3, wherein the pigment includes a pigment having at least needle-like protrusions.   A coating agent for forming the coating layer of an OA roller having a coating layer on the outer peripheral surface of a metal roller main body, which is 25 parts by mass per 100 parts by mass of the binder resin and the binder resin As described above, the coating agent for an OA roller comprising 120 parts by mass or less of a pigment and 15 parts by mass or more and 55 parts by mass or less of an amino resin as a crosslinking agent for the binder resin.

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