JPH07251119A - Screen coating method and device therefor - Google Patents

Abstract

PURPOSE:To perform screen coating of a coating material having low viscosity of such a fluidity that it drops through the meshes of screen under non- pressurization. CONSTITUTION:A coating material is pushed out to a picture line part 12 through the meshes of a screen 11. The picture line part 12 is formed into a pattern or picture lines to be applied. The 1st screen printing frame 1 provided with the screen 11 formed into the above pattern or picture lines is mounted on a surface to be coated, and also a cloth-like body 3 for absorbing and holding the coating material to be applied is laminated on the screen printing frame 1. Further, the 2nd screen frame 2 is mounted on the cloth-like body 3, and the coating material is fed into the frame 2, and a squeegee is slid on a screen 21 of the 2nd screen frame while pressurizing it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen coating method and a screen coating apparatus, for example, a flat coating such as a metal gasket is coated with a low-viscosity coating material in a desired pattern. It is useful in some cases.

[0002]

2. Description of the Related Art In the manufacture of metal gaskets for cylinder head gaskets, for example, not only the entire surface of the metal plate but only the necessary parts such as around the combustion chamber holes or around the cooling water passage holes and oil passage holes. A thin film sealing material made of rubber may be applied to the. Further, in order to enhance the adhesive force between the sealing material and the metal plate, a primer (also referred to as an adhesive) may be similarly partially coated as a base for coating the sealing material. Such partial coating pattern coating can be performed using a masking sheet by a dipping method or a spray method,
Since the loss of the masking sheet and the paint is large, the screen coating method is usually used.

In screen coating (also referred to as screen printing), a portion (image area) where a paint (also referred to as ink) is extruded, that is, a portion other than a coating pattern, is manually produced in a screen whose four edges are fixed by a frame. Alternatively, the plate coating formed by a photochemical method puts the paint to be coated in a screen plate frame that is masked to prevent the paint from being extruded, and presses and slides on the screen with a squeegee to screen the part without the plate coating. The paint is extruded through the eyes to paint the desired pattern on the object to be coated.

[0004]

The above-mentioned screen coating is usually advantageously applied when the viscosity of the paint is 100 cP (centipoise) or more, and when the viscosity of the paint is small, the paint is not flowable due to its fluidity. Even under no pressure, it drips through the eyes of the screen and ends up, leaving no screen coating. In this case, it may be possible to prevent paint dripping using a high mesh screen and enable screen coating, but the higher the mesh, the higher the price of the screen,
Since the screen is easily broken due to rubbing when pressure-sliding with a squeegee and durability is poor, it is difficult to prevent the dripping of the low-viscosity paint by increasing the mesh size of the screen, which causes a cost increase. Further, when the viscosity of the paint is 10 cP or less, it becomes impossible to prevent the paint from dripping from the eyes of the screen even if a high mesh screen is used.

When the viscosity of the paint is low, it is a common practice in screen coating to add a thickener to the paint to adjust the viscosity of the paint to a suitable level. Depending on the type of thickener and the addition ratio of the thickener, the addition of the thickener may adversely affect the original properties that the paint should have, and the properties may be deteriorated to end. In some cases, the problem of paint dripping cannot be solved by adjusting the paint viscosity by adding a thickener.

The present invention solves the above-mentioned problems in screen coating, and an object of the present invention is to apply a low-viscosity paint having a fluidity that drips through the eyes of the screen under no pressure to the object to be coated. It is intended to provide a novel screen coating method and a screen coating apparatus capable of coating.

[0007]

The screen coating method of the present invention which achieves the above object is a coating material to be coated on a first screen plate frame having a desired coating pattern, which is placed on the surface to be coated. Is laminated with a cloth-like body capable of absorbing and holding the second screen frame, and a second screen frame is further stacked thereon, and paint is supplied into the second screen frame, and the squeegee is squeezed on the screen of the second screen frame. Is pressed and slid to paint an image line of a desired pattern on the surface to be painted.

Further, the screen coating apparatus according to the present invention comprises laminating a cloth-like body capable of absorbing and retaining the paint to be coated on the first screen plate frame having a desired coating pattern, and the cloth-like body. It is characterized in that a second screen frame on which the paint to be painted is supplied and on which the squeegee is slid is loaded.

[0009]

The screen coating method and the screen coating apparatus of the present invention have the above-mentioned constitution, and the cloth-like body made of non-woven fabric, woven fabric, paper or the like capable of absorbing and retaining the paint to be coated is the first screen plate. Since it is interposed between the frame and the second screen frame, the low-viscosity paint supplied to the second screen passes through the eyes of the second screen due to its fluidity and is absorbed by the cloth-like body. , Retained. Therefore, at this time, the paint does not drip through the screen openings of the first screen plate frame.

In this state, when the squeegee is slid on the second screen frame while being pressed, the coating material absorbed and held by the cloth-like body is extruded from the cloth-like body, and at the same time, the first screen plate frame. Of the desired pattern is extruded onto the object to be coated through the eyes of the screen where the plate coating that prevents the passage of the paint, that is, the portion of the desired coating pattern is formed. Paint the wire.

In the screen coating method and apparatus of the present invention, as described above, the coating material to be coated is held by the cloth-like body, and the first screen plate frame is applied onto the screen surface without dropping the coating material from the screen eyes. It is not always necessary to use a special high-mesh screen to prevent the paint from dripping because it does not have to have a function of holding. The first screen plate frame may have a desired pattern to be painted, a mesh portion through which the paint is extruded, and a plate coating portion that prevents the passage of other paints.

Therefore, the first screen plate frame is 1
Even when a low-viscosity paint having a viscosity of 00 cP or less is coated, and when a paint having a particularly low viscosity of 10 cP or less is coated, it is easy to use and durable, which is usually used in screen coating. A 150 mesh screen can be used and it is desirable to use a screen in such a mesh range.

The paint is supplied to the second screen frame, and the supplied paint drips or flows down to the cloth-like body through the screen mesh and is absorbed. The main function of the second screen frame is to provide a surface for sliding the squeegee and hold the cloth so that the cloth does not shift its position when sliding while applying pressure to the squeegee. To hold. Therefore, for the second screen frame, a screen having the same mesh range as that of the first screen plate frame described above or a mesh having a slightly lower mesh than that of the first screen plate frame is used in terms of usability and durability.

The cloth-like material has the function of absorbing and retaining the paint to be coated as described above, and has such a function and is resistant to the paint to be coated and its solvent. Any non-woven fabric, woven fabric, paper or the like may be used. Although the cloth is through the second screen,
Since it is rubbed by a squeegee, it is desirable that it has abrasion resistance. Further, in the present invention, by appropriately adjusting the thickness of the cloth-like material to appropriately absorb and retain the cloth-like material, the squeegee slides from the first screen plate frame. The extruding amount of the paint, that is, the coating film thickness of the paint can be adjusted. However, as is already known, the amount of paint extruded through the screen varies depending on the viscosity of the paint, the size of the screen mesh, the tip shape of the squeegee, and the angle with the screen surface when sliding the squeegee. Therefore, comprehensive coordination with these elements is necessary.

[0015]

1 is an explanatory view (cross-sectional view) of an embodiment of a screen coating apparatus of the present invention. The thickness of screens, plate coatings, etc. are exaggeratedly thick for the sake of clarity. The screen coating apparatus according to the present invention comprises a first screen plate frame 1, a second screen frame 2 and a cloth-like body 3. The first screen plate frame 1 has the same structure as the screen plate frame in the conventional screen coating, and the portion where the paint is extruded on the screen 11, that is, the image portion, is the pattern to be painted (printed) on the object to be coated. The plate coating (resist) 13 is applied to the other portions of the screen so as to prevent the coating material from being extruded, except for the shape of the image line, and a desired coating pattern is formed.

As described above, it is preferable to select the mesh of the screen 11 in the range of 70 to 150 mesh in terms of usability and durability, but it is not limited to this range. The four circumferences of the screen 11 are fixed by the frame 14. This first screen plate frame is provided on the top of a flat plate-shaped object to be coated, which is placed on the coating table 5, and between the screen 11 and the upper surface of the object to be coated, that is, the surface to be coated. Is in line contact only when the squeegee is actuated, and is openably and closably spaced with a distance such that it is always separated before and after passing the squeegee, and is supported by the coating table by a support device (not shown).

The cloth 3 is laminated on the first plate frame 1 by a spacer 31 with a slight space from the screen 11. Although the cloth-like body 3 is attached to the bottom surface of the second screen frame 2 in this embodiment, the four circumferences of the cloth-like body 3 may be fixed by another frame to form an independent frame. Further, the above-mentioned spacer 31 may be omitted, and the cloth-like body 3 may be stacked so as to directly contact the screen 11. Cloth is polyester fiber, polyamide fiber, cotton,
It is formed of one or more sheets of non-woven fabric or woven fabric made of fibers such as wool or paper such as Japanese paper.

The screen 21 of the second screen frame 2
In the illustrated embodiment is a first screen plate frame 1
Like the screen 11 of the drawing, the drawing section 2 through which the paint passes
2 and a plate coating 23 that prevents the passage of paint,
The drawing portion 22 is formed in a shape similar to the shape of the drawing portion 12 of the screen 11. In the figure, the image area 22 is formed to be larger than the similar image area 12 of the screen 11, but may be formed to have substantially the same size as the image area 12 or smaller than the image area 12. You may form. In this way, by changing the size of the image area 22 in comparison with the size of the image area 12, it is possible to adjust the supply of the paint to the cloth-like body 3 to some extent.

The screen 21 of the second screen frame 2
May have no plate coating 23 and allow the paint to pass through the entire surface of the screen 21, but in this case, the paint is impregnated and held in the entire cloth-like body, so that the loss of the paint increases. Sometimes. Reference numeral 24 is a frame that fixes the four circumferences of the screen 21, and is fitted into the frame 14 of the first screen plate frame 1 exactly. 4 is a squeegee.

Screen coating was performed as follows using the screen coating apparatus as shown in FIG. 1 described above. That is, a metal gasket made of a stainless steel plate (size is approximately 150 mm × 200
mm, thickness 0.25 mm) as the object to be coated, and a pattern of surrounding the combustion chamber opening of the gasket and the liquid passage holes such as cooling water passage holes and oil passage holes with a predetermined width. A rubber-sealed film-coated primer was applied to. The primer is Monicas VT manufactured by Yokohama Polymer Research Institute
Experiments were carried out on two types, -200 (viscosity about 3 cP) and ChemFloc 607 (viscosity 3-7 cP) manufactured by Lord Far East. By using a nonwoven fabric GS felt (trade name of Toray Industries, Inc.) 223050N (thickness 0.5 mm) made of polyester fiber and polyurethane fiber as a cloth-like body, even if the primer has a low viscosity as described above, The desired shape and pattern could be applied by screen coating.

At this time, the screen of the first screen plate frame was 125 mesh, and the screen of the second screen frame was 72 mesh screen. As the squeegee, a commonly used rubber squeegee was used. As a comparative example, a conventional screen coating apparatus using only the first plate frame was used to screen-coat the same object to be coated with the above-mentioned two kinds of primers by the conventional method. However, none of the primers could be dropped from the screen and applied in a desired shape pattern, even though the screen of 300 mesh was used.

[0022]

As described above, according to the screen coating apparatus and the screen coating method of the present invention, the coating material drips from the eyes of the screen unless a high mesh screen is used in the conventional apparatus and method. Screen coating for such low viscosity paints is easy to use, durable and not expensive,
This can be done using a normal screen. Further, even for a low-viscosity paint which cannot be screen-coated even if a high-mesh screen is used conventionally, screen-coating can be carried out using the above-mentioned ordinary mesh screen. Therefore, according to the present invention, it is possible to extend the application of the screen coating to a low-viscosity coating which has been difficult to apply in the past, and it is not necessary to use a high-mesh screen, and a thickener is used. Since it is not necessary to increase the viscosity, the cost of screen coating of low-viscosity paint can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view (cross-sectional view) of a screen coating apparatus of the present invention.

[Explanation of symbols]

 1 1st screen plate frame 2 2nd screen frame 3 Fabric 11 and 21 Screen 13 and 23 Plate coating

Claims (4)

[Claims] 1. A cloth body capable of absorbing and retaining a coating material to be coated is laminated on a first screen plate frame having a desired coating pattern, which is placed on the surface to be coated, and further thereon. The second screen frame is loaded on the second screen frame, the paint is supplied into the second screen frame, and the squeegee is pressed and slid on the screen of the second screen frame, and the image of the desired pattern is drawn on the surface to be coated. A screen coating method, characterized in that 2. The paint has a viscosity of 100 cP (centipoise) or less, and the first screen plate frame has a viscosity of 70 to 15
The screen coating method according to claim 1, comprising a 0 mesh screen. 3. A cloth body capable of absorbing and retaining a coating material to be coated is laminated on a first screen plate frame having a desired coating pattern, the coating material to be coated is supplied and the squeegee slides. And a second screen frame to be loaded on the cloth-like body. 4. The screen coating apparatus according to claim 3, wherein the second screen frame has a paint passage pattern similar to the coating pattern of the first screen plate frame.