JPH04131162A - Coating method - Google Patents

Abstract

PURPOSE:To apply a coat accurately on both surfaces of a stuff to be coated by allowing a board to be coated, to the both surfaces of which a coating liquid is applied, to pass through an area between two bar coaters installed in parallel in close proximity to each other and scraping coating material stuck to the both surfaces of the board using the bar coater. CONSTITUTION:A board to be coated, to the both surfaces of which a coating liquid is applied, is allowed to pass through an area between two barcoaters installed in parallel in close proximity to each other at a speed of 100m/min. or lower. Then the coating material to the both surfaces of the board is scraped off using said two bar coaters, and the coating material applied to the both surfaces of the board is adjusted to a target coating application amount level simultaneously. Subsequently, a coat is uniformly formed over the both surfaces of the board with high accuracy simultaneously. Further, much equipment cost is not required and a wide range of different types coating materials can be applied. Also the coating material applied uniformly and accuracy for a thin film having a thickness of 20mum, especially about 0.5 to 5mum. This method is effective especially in the field where a regist film calling for strict uniformity of a film thickness is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating method for adjusting the amount of coating liquid applied to both surfaces of a plate to be coated. More specifically, a coating method in which a plate coated with paint liquid on both sides by dip coating etc. is passed between two bar coaters to scrape off the excess paint and adjust the coating amount to the target coating amount on both sides at the same time. Regarding.

(Conventional technology and its problems) Conventionally, it has been used to protect objects to be coated, provide cosmetic properties, and various other performances, such as slip properties, antistatic properties, easy adhesion, difficult adhesion, abrasion resistance, and gas barrier properties. Coating with various paints is widely used to provide materials such as paints, etc., or to coat resists for image formation. In recent years, coiled continuous sheets,
In the field of painting cut boards, the coating film can be coated uniformly and accurately on both sides simultaneously due to the advancement of various required properties such as finished appearance, resource saving, high productivity, and high-mix low-volume production. There has been an increasing demand for a coating method that is inexpensive and can be applied to a wide range of paint types, and there are cases where existing coating methods cannot satisfy the requirements.

Conventional coating methods include dipping coating method, shower coating method, spray coating method, squeeze coating method, screen printing method, curtain flow coating method, electric @ coating method, roll coating method, etc. In the shower coating method and spray coating method, the thickness is 20 or less, especially 0.
．． It is difficult to accurately apply a uniform coating film of about 5 to 5P on both sides at the same time, and in methods that combine these coating methods with the squeeze coating method, the film thickness obtained by squeezing is limited to a narrow range (thin range). There is a problem of being exposed. The screen printing method and the curtain flow coating method can only coat one side at a time, and the TT coating method requires high equipment costs, limits the types of paint that can be used, and has problems in terms of high productivity. The roll coating method has problems such as poor pick-up properties depending on the type of paint, making it impossible to paint, and roll marks being likely to appear. In particular, when applying roll coat paint to cut boards, it is necessary to paint with natural rotation, which tends to cause roll marks to appear, and there are many restrictions on the type of paint and painting conditions, and there are problems such as high equipment costs. .

(Means for Solving the Problems) Therefore, in order to meet the above requirements, the present inventors have devised a method that can apply a coating film uniformly and precisely to both sides of the object at the same time, and that does not require much equipment electricity. As a result of intensive study to find a coating method that can be applied to a wide range of coating types, we found that after coating both sides of the object using a dipping method, etc., the object was sandwiched between two wooden bar coaters. The inventors have discovered that the above problem can be solved by scraping off the excess 114, and have arrived at the present invention.

That is, in the present invention, both sides of the plate to be coated are coated with the coating liquid by passing the plate coated with the coating liquid onto both sides of the plate at a speed of 1.00 m/min or less between two bar coaters installed close to each other in parallel. To provide a coating method characterized by scraping off residual paint with said two bar coaters and simultaneously adjusting the coating amount of paint applied to both sides of said plate to a target sludge coating amount. It is something to do.

(e.g. zinc, aluminum, sub-1Ω-aluminum alloy, iron-zinc alloy, tin) Metal plates such as steel plates, stainless steel, plastic plates such as polyethylene terephthalate, vinyl chloride, polyethylene: These metal plates and plastic plates have a surface Examples include those that have undergone treatment and those that have a brimer coating formed thereon, and these may be in the form of a continuous coiled sheet or in the form of a cut plate.

The coating liquid can be applied to both sides of the plate to be coated using any method that can apply the coating liquid to both sides, such as the shower method, spray method, or dip coating method. It is preferable in terms of cost and equipment cost.

In the method of the present invention, the coated plate coated with the coating liquid is passed between two bar coaters installed close to each other in parallel, and the passing speed is 100 m/min or less, preferably 0.5 m/min. min to 50m/min, more preferably 1m
If the passing speed exceeds 60 m/min to 10 m/min, large vibrations will occur on the moving plate, causing the paint on the plate to scatter, or the amount of coating may not be adjusted properly. This is undesirable because it causes problems such as the bar coater running out or the bar coater being worn significantly.

In addition, the two installed bar coaters scrape off excess paint on both sides of the plate to be coated, and adjust the amount of paint applied according to the bar coater number. In order to prevent a gap from forming between the plate to be coated and the contact point between the outer part of the wire wound around the bar coater and the plate to be coated, and to ensure that the plate to be coated passes smoothly between the two bar coaters. In order to pass, it is necessary for two bar coaters to press down the Wt coated plate with an appropriate force when the coated plate passes. The pressure (pressure perpendicular to the coated surface) used to press the coated plate is not particularly limited, but it is usually 3 g/cm to A range of 350 g/cm is appropriate;
Preferably it is 20 g/cm to 200 g/am, more preferably 20 g/am to 70 g/am. If the tightening pressure is too low, the bar coater will likely not be able to sufficiently hold down the plate to be coated, creating a gap between the bar coater and the plate, making it difficult to coat uniformly. On the other hand, if the tightening pressure is too high, the pressure becomes too strong, which tends to cause problems such as the plate to be coated not passing through smoothly, the plate to be coated to be damaged, and the bar coater to wear significantly.

Also, it is preferable to set the two bar coaters so that the force is applied uniformly in the width direction of the plate to be coated, and the method of holding and tightening the plate with the two bar coaters is as follows.
The length direction of the bar coater is perpendicular to the direction of movement of the plate to be coated, and the line connecting the centers of the circles of the two bar coater rods is also perpendicular to the direction of movement of the plate to be coated. It is preferable to set it to . For example, when the plate to be coated passes horizontally, two bar coaters are placed one above the other, and the lower bar coater is fixed with screws so that it is in contact with the plate and does not rotate. One method is to prevent the upper bar coater from rotating, apply the same vertical load to both ends of the bar coater, and use gravity to press the plate to be coated. In addition, when the plate to be coated passes vertically, arrange two bar coaters horizontally and in parallel, fix one bar coater with screws, etc., and prevent the other bar coater from rotating. Examples include a method of applying a load that converts gravity into a horizontal force to both ends of the plate to press the plate to be coated.

In addition to gravity, springs can also be used to hold down the coated plate with a bar coater.

The object to be coated can be held down to some extent by applying a load to only both ends of the bar coater, but if the passing speed of the plate to be coated becomes faster or the width of the plate to be coated becomes wider, the bar coater will sag and the center part of the plate to be coated will bend. Coating amount adjustment may not work properly. In order to eliminate this deflection of the bar coater, it is preferable to press the bar coater against the plate to be coated at areas other than both ends of the bar coater, and for this purpose, a reinforcing plate, a reinforcing rod, or the like can be used to press the bar coater.

In the method of the present invention, when applying the paint liquid to the object to be coated by the dip coating method, two bar coaters for adjusting the paint application are installed on the dipping tank, and the coating liquid is scraped off by the bar coaters. Preferably, the setting is such that excess paint is returned to the dipping tank.

The paint used in the method of the present invention can be used without limitation as long as it is a liquid paint that can be coated with a bar coater, such as acrylic, polyester (oil-free polyester, alkyd), epoxy, vinyl acetate, etc. These may be of a water-diluted type or an organic solvent-diluted type, and may be any of a room temperature curing type, a heat curing type, and an actinic ray curing type using ultraviolet rays. The viscosity of the paint can be set appropriately within a range that ensures a good painted surface appearance due to the flow of the ml film after the applied paint is scraped off with a bar coater, and that does not cause sagging or twisting of the paint film. , 10-1.000 cps, preferably 20-300 cps by Brookfield viscometer (60 rpm)
It is within the cps range. The film thickness is usually determined from the viewpoint of paintability.
Dry film thickness: 03-80F+, preferably 0.5-40P
6 In the method of the present invention, "bar coater" is defined by JIS K
5400 (7,5), that is, a stainless steel rod with a diameter of 6.35 mm and a length of about 400 mm, wrapped with stainless steel wire without any gaps, and the bar coater specified in JIS. ,
It is also possible to use rods with different diameters, lengths, and materials, as well as wires wrapped around rods with different materials. The diameter and length of the rod are not particularly limited, but usually the diameter is 5~
50Il1m, length ranges from 100 to 1,000 meters. The material of the rod is not limited to stainless steel, but any material having sufficient strength and elasticity, such as duralumin, can be used. The material of the wire is not limited to stainless steel either, and any material having sufficient strength and wear resistance, such as nickel, can be used. The thickness of the paint film that is applied increases depending on the thickness of the wire wrapped around the rod.

In the method of the present invention, after adjusting the coating amount of paint on both sides of the plate to be coated, whether the plate is in the form of a continuous sheet or a cut plate, it is then moved to a curing step.

When the object to be coated is in the form of a continuous sheet, it is continuously transferred to a curing process such as baking. In the curing process, a three-dimensionally crosslinked coating film may be formed, or an apparently cured uncrosslinked film such as a resist film may be formed. When the plate to be coated is in the shape of a cut plate, After adjusting the amount of paint applied, the same goes to the curing process.

(Operations and Effects) The method of the present invention allows coating to be applied uniformly and precisely to both sides of the object at the same time, and does not require much equipment cost.
Moreover, a wide range of paint types can be applied, and even thin films of 20 pm or less, especially about 0.5 to SP, can be applied uniformly and accurately. This method is particularly effective in the field of resist coating film formation, where uniformity of film thickness is strictly required, because as the film thickness increases, resolution accuracy decreases, and on the other hand, as the film thickness decreases, chemical resistance decreases.

Hereinafter, the method of the present invention will be specifically explained with reference to Examples.

Example 1 An aluminum plate with a length of 50 cm, a width of 25 cm, and a thickness of 0.15 mm was coated with Vinizol 2018 (Daido Chemical Industry Co., Ltd. liquid) in a dipping tank. are two # specified in JIS K5400 (7, 5) tightened to a pressure of 35 g/cm.
The coating liquid was scraped off by passing it horizontally between the 14 bar and the coater (manufactured by Matsuzuki Sangyo ■) at a speed of 2 m/min.
It was dried at ℃ for 10 minutes.

Example 2 A solid content concentration of acrylic copolymer (Note 1) 10 was applied to a sparrow board with a length of 50 cm, a width of 25 cm, and a thickness of 0.15 mm.
% solution in a dipping tank, and #10 bar coater and #20 bar coater (#10 bar coater and #20 bar coater ( Both are JIS K5400 (7,5
), the coating liquid was scraped off by passing it vertically from bottom to top at a speed of 2 m/min between 8.
It was dried for 10 minutes at 0°C.

(Note 1) Methyl methacrylate/n-butyl methacrylate = 1/1 (weight ratio) Number average molecular weight obtained by radical polymerizing mixed monomers in isobutyl acetate.
．． The coated plates obtained in Examples 18 and 2 of 000 acrylic copolymer both exhibited smooth and good appearance when visually observed. The coating thickness and coating thickness distribution of these coated plates were measured using an infrared coating thickness meter.

The results are shown in Table-1.

Table-1

Claims (1)

[Claims] 1. The coated plate coated with paint liquid on both sides is passed between two bar coaters installed close to each other in parallel at a speed of 100 m/min or less. A painting method characterized in that the paint applied to both sides is scraped off with the two bar coaters, and the paint applied to both sides of the plate to be coated is simultaneously adjusted to a target amount of paint applied. 2. The coating method according to claim 1, characterized in that the plate coated with the paint liquid by being immersed in a paint liquid dipping tank is passed between two bar coaters installed on the dipping tank. .