JPH0919657A - Formation of coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of the cissings, bubbles, etc., of a coating liquid and to form a defect-free coated surface by applying the coating liquid, a solvent for the coating liquid or a mixture composed thereof on an object to be coated, then pressing the object to be coated by a blade prior to drying. SOLUTION: Flanges 7 are previously fitted to both ends of the work 3 and internally expanding collets 8 are set into flange holes. The work 3 is rotated by a stepping motor 13 in the state of horizontally supporting the work. Next, headers 5, 17 set at one end of the work 3 are lowered to bring a sponge tube (blade) 1 into contact with the work 3. A pump 15 is driven in this state and simultaneously a stepping motor 28 is turned on to move the system of the sponge tube 1 and a polyethylene tube 2 to the other end of the work 3. The coating is started by turning on the pump 19 when an injection needle 21 arrives at the coating start position of the work. The coating liquid is pressed to the work 3 by using the blade 1 before drying of the applied coating liquid, by which the good coated surface is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating film, and more particularly to a method for forming a coating film having a constant film thickness on a work having a poor surface condition.

[0002]

2. Description of the Related Art Conventionally, when a coating film having a constant film thickness is to be provided on a substrate, the dimensional accuracy, surface roughness, surface defects, etc. of the substrate can be obtained with a desired accuracy. To a level required for processing, to remove stains adhering to the substrate by processing such as drawing, ironing, polishing, and cutting, and then removing the dirt that adheres during such processing. It was possible to obtain a coating film of.

[0003]

However, in such a conventional method, the number of steps is very large, and it is very wasteful in view of time, cost and defective product rate in each step. More specifically, since a process including completely different operations such as metal working, washing, and coating must be performed, the carrying method becomes very complicated first. Since the method of gripping the work (base material or base body) is different for each process, it takes time to replace the jig when the size of the work is different, so-called setup change. The present inventor has noticed that this problem will be solved if all of them can be replaced by coating, and has already proposed it as Japanese Patent Application No. 6-259429. That is, a cylindrical or columnar substrate is supported horizontally, the coating liquid is supplied to the surface while rotating the substrate, and then the coating surface forming member is rotated on the substrate before the coating liquid loses fluidity. This is a method for forming a coating film which is in parallel with the axis and is brought into contact with the coating surface. In this method, the dimensional accuracy and surface roughness are improved by coating, and most of the surface defects are hidden, but they are hidden under the surface that looks smooth due to particularly large scratches or ironing or burnishing. Nest-like scratches, spots where foreign matter is attached and surface tension changes, etc., the coating liquid may be repelled by the normal coating method. Even if it is obtained, it may be repelled during film fixing such as air-drying or curing, or the air contained therein may be expanded to form bubbles, or repelled to form a part without a crater film. The above situation is the same when the functional film is directly applied to the metal-processed surface, and in any case, the surface smoothness is adversely affected.

[0004]

Therefore, as a result of earnest studies, the present inventor has applied a force for pressing the coating liquid or the like against the substrate or the like after applying the coating liquid or the like to the work such as the substrate and before drying. As a result, they have found that it is possible to prevent the occurrence of the above-mentioned repellency and bubbles, and arrived at the present invention. That is, the object of the present invention is:
It is to obtain a substrate surface with few defects by coating while omitting outer diameter processing and washing, and to obtain a functional film with few defects. Another object of the present invention is to extrude aluminum.
An object of the present invention is to provide a coating method for improving the surface condition of a base material having a poor surface condition such as an electric resistance sewing material and a paper material by coating so as to eliminate defects caused by the base material when used as various base materials. . Further, when a functional film is applied to a substrate that has undergone ordinary processing such as drawing, polishing, ironing, and cutting, or a substrate obtained by the above method, it provides a means for removing the cause of defects remaining on the substrate. It is also to do.

In particular, when a substrate for an electrophotographic photosensitive member is manufactured by coating from a substrate having a low degree of processing and it is desired to prevent problems caused by accuracy of outer diameter, surface roughness, surface defects, or the like, or When a functional film is to be directly applied to a substrate obtained by the processing method described in 1. above, a means for obtaining a coating film with few defects, particularly a functional film, without providing a separate step such as cleaning should be provided. Is.

The object of the present invention is, in a method for forming a coating film on a work, after coating a coating solution, a solvent for a coating solution or a mixture of a solvent for a coating solution and a coating solution with a blade before the drying. A coating film forming method characterized by pressing the coating body, more preferably the work is held substantially horizontal,
A method for forming a coating film which is a rotating cylinder or a cylinder, or a method for forming a coating film having a constant film thickness on a work, which comprises a coating liquid, a coating liquid solvent or a coating liquid solvent and a coating liquid. A step of applying a coating solution which is one of a mixture of, and a step of moving the blade so that the coating solution does not separate from the applied coating solution before drying, and pressing the applied coating solution. A method for forming a coating film having a constant film thickness, which comprises a step of forming a coating film having a constant film thickness, a method for forming a coating film having a constant film thickness on a work, which is for coating liquid or foam liquid A step of applying a coating solution that is either a solvent or a mixture of a coating solution solvent and a coating solution, and moving the work so that the blade does not separate from the coating solution before the coating solution dries. , A step of pressing the applied coating liquid, forming a coating film having a constant film thickness Method for forming a uniform film thickness of the coating film made of extent, and the movement of such a work is easily accomplished by methods translatory movement.

The present invention will be described in more detail below. The feature of the present invention is that the coating itself or pre-coating using various coating liquids prior to full-scale coating is performed, and the coated coating liquid is applied to the work (base material or substrate) with a blade before drying. By pressing the liquid, the coating liquid is embedded in the defective part on the base, or the coating liquid is applied to the work surface by the blade to solve the problem of surface tension and to obtain a coating surface with few defects. To do.

That is, the central idea of the present invention is to press the coating liquid against the surface of the work by means of a blade to spread the coating liquid to the defective portion and the abnormal surface portion, and eliminate the defects from the surface after coating. The blade used in the present invention is
The material is not particularly limited as long as it is a material that is not severely attacked by the coating liquid or the solvent for coating liquid, but rubber is preferable because it is pressed with an appropriate pressure.

With respect to the pressing force, this may cause another defect, spiral unevenness or shading. At this time, the viscosity of the liquid to be used and the pressure may be adjusted according to the size of the scratch and the degree of abnormality, but normally the pressure is about 1 to 20 g as the load per 10 mm of the length of the pressed blade. preferable. Further, when the coating film to be obtained in the final state is thick, it is preferable to carry out the preliminary coating and the full-scale coating separately, and to adopt this method only for the preliminary coating. Various kinds of force can be applied for pressing, but concretely, the pressing force may be air pressure, (rubber) elasticity, gravity, electromagnetic force, etc. Since it is usual to do so, the former three are common.

Solvent-resistant rubber balloons for air pressure,
(Rubber) For elasticity, a sponge rubber tube or piano wire is combined with a solvent resistant rubber sheet or a round bar, and for gravity, a contact surface with a work is flat and a drip is dropped. For a liquid having a wet film thickness of 50 μm or more as a liquid to be applied in order to eliminate defects, it is preferable to use the coating liquid itself and divide it into preliminary coating and full-scale coating. When the wet film thickness is 50 μm or less, a solvent may be first applied and pressed, and then the coating liquid may be applied, or in some cases, a coating liquid diluted with a coating liquid solvent may be applied in advance and then full-scale application may be performed.

In any case, in the system in which the work is horizontally rotated, the liquid is discharged from the nozzle, and the blade is rubbed in the vicinity of or integrally with the discharge nozzle, two stages are not provided and coating is not performed separately. It is preferable to perform the coating twice continuously in one stage. When carrying out the present invention, a typical work flow is a coating liquid on a work,
A step of applying a coating solution that is either a coating solution solvent or a mixture of a coating solution solvent and a coating solution, so that the blade does not separate from the coated coating solution before the coating solution dries. The steps include exercising and pressing the applied coating liquid, and forming a coating film having a constant film thickness. Of these, the work may be moved instead of moving the blade. It is preferable to move the work when mass production, when the coating surface is a curved surface, particularly when the surface is cylindrical,
Preference is given to rotational movement.

The present invention will be described in more detail below with reference to the drawings. The coating method of the present invention can be suitably used particularly for a method for producing a substrate of an electrophotographic photoreceptor and a method for coating a substrate. FIG. 1 shows an example of a blade structure using a sponge rubber tube as a blade. The ethylene propylene rubber sponge tube 1 is used as a blade, the polyethylene tube 2 is passed through the blade, and the polyethylene tube 2 is discharged from the vicinity of the portion where the sponge tube 1 contacts the work 3 and the liquid is discharged.

The polyethylene tube 2 is attached to the injection needle 4, and the ethylene propylene sponge tube is fixed to the attachment portion 4'of the injection needle 4 to the header 5 with a hose band 6. The polyethylene tube 2 penetrates through the side wall of the sponge tube 1, and the end of the polyethylene tube 2 is slightly exposed from the surface of the sponge tube 1 that contacts the work, or if the tube is thick, it is opened in the side wall. You may. When the blade 1 is exposed to the outside, it is preferable to open the blade 1 slightly upstream of the position where the blade 1 contacts the work 3.

FIG. 2 shows a coating device. The flanges 7 are previously fitted to both ends of the work 3, and the inner expanding collet 8 is set in the flange holes to be supported horizontally. At this time, the flange may be adhered or simply fixed. The inner expanding collet 8 is attached to a rotary shaft 9, and the rotary shaft 9 is fixed to a bearing 10. A gear 11 and a timing belt 12 are attached to the rotary shaft 9, and the stepping motor 1
The belt 12 is hung on the gear 3 attached to the motor 3 and the gear 11 attached to the motor 13, and the rotation of the motor 13 is transmitted to the work.

A tube 14 is connected to the header 5, and the tube 14 is connected to a pump 15 and a liquid reservoir 16. In parallel with the header 5, another line header 17, a tube 18, a pump 19, and a liquid reservoir 20 are provided.
An injection needle 21 is attached to the header 17, and if necessary, a polyethylene tube and a sponge tube (both not shown) are provided as in the first series.

The headers 5 and 17 are fixed to the mounting member 22, and are vertically moved by a stepping motor 24, a ball screw 5, and a nut (not shown) which are separately set in the mounting member 23. Further, the mounting member 23 can be moved left and right at an arbitrary speed by a ball screw 26, a guide 27, a stepping motor 28, and a nut (not shown).

First of all, the headers 5 and 17 set at one end of the work 3 fixed to the inner expanding collet chuck 8 by fitting the flange 7 are lowered, and the sponge tube 1 is moved to the work 3
, And the tip of the injection needle 21 stops at a position where a gap of 2 to 5 mm is formed from the work. At the same time as the pump 15 is driven, the stepping motors 13 and 28 are turned on to rotate the work and move the system of the sponge tube 1 and the polyethylene tube 2 to the other end of the work 3.

When the injection needle 21 reaches the application start position of the work, the pump 19 is turned on to start full-scale application. In some cases, full-scale application may be performed by simply ejecting from the syringe 21, and in some cases, rubbing with a sponge tube as in the case of preliminary application. When the sponge tube 1 reaches near the other end of the work 3, the operation of the pump 15 is stopped, and then the injection needle 2
When 1 or the sponge tube reaches near the other end of the work 3, the pump 19 is stopped and the application is completed.

The work 3 moves to the next step, and the sponge tube 1, the injection needle 21 or the sponge tube enters the cleaning step. Solvent resistance, flexibility and elasticity may be satisfied as the blade material used. For example, ethylene propylene sponge tube can be used. As this tube, for example, "EPT Sponge 18" manufactured by Shinkawa Rubber Co., Ltd.
/ 6φ "or the like can be preferably used.

As the size, the outer diameter is 12 to 22 mm, the inner diameter is 3 to 8 mm, the length from the fixed position of the sponge tube to the adhesion to the work is 30 to 80 mm, and the total length of the sponge is 10 to 50 mm. The sponge is preferably a closed-cell sponge, and the force for pressing the work varies depending on the viscosity of the liquid to be applied, the inherent concentration, and the surface condition of the substrate to be applied, but a force of 1 to 20 gf is usually used.

As the tube for transporting the coating liquid to the portion where the work and the blade come into contact with each other, any material can be applied as long as it is solvent resistant and has a certain degree of flexibility, but a low density, low molecular weight, polyethylene tube is usually used. Good. The inner and outer diameters are 0.5 to 3 mm and 0.2 to 1.0 mm, respectively.
The one that fits the injection needle well is used.
It is desirable that the lock part of the injection needle is made of metal.
Since the tip of the injection needle is cut off at a point of about 5 to 20 mm and a polyethylene tube is fitted into the remaining tip for use, it is preferable that the outer diameter be substantially equal to the inner diameter of the polyethylene tube. The inner diameter of the injection needle should be as large as the strength conditions permit. It is preferable to use a solvent for a coating solution as the solvent, but acetone, ethanol, tetrahydrofuran, etc. can be used for the aluminum tube.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded. In the following, "part" means "part by weight". (Example 1) Aluminum extrusion pipe (material A1050, inner diameter 2)
The flange was set to 6 mm, outer diameter 29.50 mm, and length 260 mm), horizontally supported, and UV curable resin was applied to this, and this method was applied to the operation of improving the outer diameter accuracy by bringing the bar close.

The UV curable resin comprises urethane acrylate A, 2-acryloyloxyethyl phthalate B, dicyclopentenyloxyethyl acrylate C, 1-hydroxy-cyclohexyl-phenyl ketone D, and benzophenone E. A: B: C: D: E = 30: 10:
The viscosity was 40: 0.8: 0.8 (polymerization ratio) and the viscosity at room temperature was 500 mPas.

First, the UV curable resin is discharged from the polyethylene tube 2 so as to have a film thickness of 20 μm (0.
57 ml / min), by rubbing an aluminum extruded tube with ethylene propylene sponge 1 and averaging a film thickness of 130 from the injection needle 21 50 mm away from the polyethylene tube 2.
The resin was discharged in a spiral shape so as to have a size of μm (3.7
ml / min). The discharged resin was leveled to form a substantially smooth coating surface. Work rotation 300 rpm, nozzle pitch 1 mm / revolution.

Then, a stainless steel bar was brought close to the work 3 in parallel with the axis of rotation of the work, the bar was rotated in the same direction as the work to scrape off excess UV resin, and then the bar was moved away from the UV light to 2000 mJ / cm ² . The irradiation was performed so that the accuracy correction operation of the aluminum extruded tube with the UV resin was completed. The rotational runout of the aluminum extruded pipe before and after the accuracy correction was measured at the same position and changed from 110 μm to 30 μm. 1
The operation of correcting 0 pieces was performed, but no blister or crater-like uncoated portion was observed.

(Comparative Example 1) Except for the polyethylene tube 2 and the ethylene propylene sponge tube 1, application using this discharge system was not carried out, and the injection needle 21 was used to carry out discharge to an average film thickness of 150 μm ( 4.3 ml / m
in) was performed in the same manner as in Example 1. After the spiral application from the injection needle 21, the UV resin leveled and became a substantially smooth surface. After the correction operation with the stainless steel bar, a smooth surface was obtained as in Example 1, but after being irradiated with UV light and cured. As a result of observation, two blisters and three crater-shaped uncoated portions were observed.

Example 2 An aluminum drum mirror-cut with a diamond bite (material A6063, outer diameter 30.00)
mm, length 260.5 mm, seal wax inner diameter 28.5 m
m) was applied with the cutting oil still attached. As a coating liquid, 1.4 parts of dioxane, 6 parts of tetrahydrofuran
4 parts, 16 parts of polycarbonate ("Novarex 7030A" manufactured by Mitsubishi Chemical Corporation), 9.8 parts of a hydrazone compound represented by the following formula (1),

[0028]

Embedded image 2.4 parts of a hydrazone compound represented by the following formula (2),

[0029]

Embedded image 0.1 part of a cyano compound represented by the following formula (3),

[0030]

Embedded image

A liquid for a charge transfer layer containing was used. Separately from the above solution, a solution was prepared in which the number of solvent parts was twice diluted.
Using the apparatus of Example 1, a solution diluted with the same number of revolutions and at the same pitch is wet from the polyethylene tube 2 to a film thickness of 20 μm.
Then, the ethylene propylene sponge tube 1 was applied and smoothed by pressing, and the charge transfer layer liquid was discharged from the injection needle 21 to a film thickness of 92 μm.
The injection needle was set to have a 1 mm gap from the work. The spirally discharged liquid was leveled by surface tension, and after rotating and air drying, a smooth surface was obtained. Five drums were coated under the same conditions, but no coating defect occurred.

(Example 3) A mixed solvent of 1.4 dioxane and tetrahydrofuran (34:66) was discharged from the polyethylene tube 2 to a size of 16 μm, and the volume was adjusted to 95 μm from the injection needle. The operation of discharging the coating liquid was performed under the same conditions as in Example 1. In the coating with 5 coatings, one defect was found on each smooth coating surface obtained after air drying.

(Comparative Example 2) Except for the ethylene propylene sponge tube 1 and the polyethylene tube 2, prior coating was not performed, and the coating solution of Example 4 was discharged from only the injection needle 21 to 95 μm. Most of the spirally discharged liquid was smoothed, but some unsmoothed spots remained in spots.

[0034]

According to the method of the present invention, the repellency and bubbles of the coating liquid can be prevented and a coated surface with few defects can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a blade structure in the present invention.

FIG. 2 is an explanatory view of a coating device used in the present invention.

[Explanation of symbols]

 1 Blade made of sponge tube 2 Polyethylene tube 3 Work 4 Injection needle 5 Header 6 Hose band 7 Flange 8 Expanding collet 9 Rotating shaft 10 Bearing 11 Gear 12 Timing belt 13 Stepping motor 14 Tube 15 Pump 16 Liquid reservoir 17 Header 18 Tube 19 Pump 20 Liquid reservoir 21 Injection needle 22 Mounting bracket 23 Mounting bracket 24 Stepping motor 25 Ball screw 26 Ball screw 27 Guide 28 Stepping motor

Claims (6)

[Claims] 1. In a method for forming a coating film on a work, after applying a coating liquid, a solvent for a coating liquid or a mixture of a solvent for a coating liquid and a coating liquid, an object to be coated is pressed by a blade before drying. A method for forming a coating film, comprising: 2. The method according to claim 1, wherein the coating is performed again after the pressing. 3. The coating film forming method according to claim 1, wherein the work is a cylinder or a cylinder that is held substantially horizontally and is rotating. 4. A method for forming a coating film having a constant film thickness on a work, which is a coating liquid, a coating liquid solvent, or a mixture of a coating liquid solvent and a coating liquid. A step of applying the liquid, a step of moving the blade so that the coating liquid does not separate from the applied coating liquid before being dried, and a step of pressing the applied coating liquid, forming a coating film having a constant film thickness And a step of forming a coating film having a constant film thickness. 5. A method for forming a coating film having a constant film thickness on a work, which is a coating liquid, a coating liquid solvent, or a mixture of a coating liquid solvent and a coating liquid. A step of applying a liquid, a step of moving the work so that the blade does not separate from the applied coating liquid before the coating liquid dries, and a step of pressing the applied coating liquid, a coating film having a constant film thickness And a step of forming a coating film having a constant film thickness. 6. The motion of the work is a rectilinear motion.
The described method.