JPS59142870A - Painting method by curtain flow coater - Google Patents

Abstract

PURPOSE:To convey smoothly a material to be coated without oscillating and to prevent the generation of uneven color and build-up by interposing a cushion material having elasticity between the rear of said material and the surface of a conveyor, and painting the material with a curtain flow coater. CONSTITUTION:A paint 6 fed from a paint tank 1 by a pump 5 into a pouring head 3 falls in the form of a thin curtain from a slit 7 provided in the bottom of said head 3. The paint 6 is coated on the surface of a material 9 to be coated placed on a jig plate 14 when the material 9 is passed underneath the paint curtain 10 by the operation of conveyors 4-1 and 4-2. Any of the known curtain flow coater is usable in this method. The colored transparent or colored translucent paint to be used provides a much better effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a curtain 70-coater (r C, F
Regarding improved coating methods (sometimes abbreviated as ``coaters''), in particular coating methods that can eliminate color unevenness and the occurrence of υ due to paint embankments, and can achieve a uniform color tone and painted surface. It is.

C and F coaters are currently widely used to coat flat plates such as wooden boards, metal boards, and inorganic boards. It has the following advantages. The mechanism of the C and F coaters, as shown in FIG.
-2 is the main part. That is, when the paint 6 sent from the paint tank 1 to the boring head 3 by the pump 5 reaches a certain level, it is extruded at a constant flow rate from the slit 7 at the bottom of the head 3, forming a thin curtain shape. The paint flows down, is collected in the paint receiver 8, and is then collected in the paint tank l. On the other hand, the object 9 to be coated is
When it is placed on the conveyor 4-1 and conveyed to pass under the paint curtain 10 flowing down from the slit 7, the surface of the object to be coated 90 is painted and a coating film 11 is formed, and
The object to be coated 9 that has passed through the paint curtain 10 is transferred to a conveyor 4-1.
It is transferred onto the transport machine 4-2, which is moving in the same direction as the transporter 4-2.

Regarding the paint finish properties of such C and F coaters,
There is no particular problem when painting with a colored opaque finish so that the surface of the workpiece is mostly or completely hidden by the paint color. When painted or when painted with a paint with poor fluidity, linear color unevenness or areas where the paint film is embanked in a direction almost perpendicular to the direction of movement (transportation) of the object to be painted, etc. This results in a defect that significantly impairs the aesthetic appearance, and there is a strong desire to improve it.

The inventor investigated the causes of these defects and found that, in the process of loading and conveying the object to be coated on a conveyor, based on FIG. (2) When the rear end of the workpiece 9 leaves the tip of the conveyor 4-1 after passing through the conveyor 4-1, (3) When the boring head is moved Two installed (double head type) C and F coaters (not shown), conveyor 4-1
A rotating roll (in the present invention, the rotating roll is also included in the scope of the conveying machine) is provided between the K1 and the conveyor 4-2 to smoothly convey the object 9 to be coated. (4) When the object to be coated 9 passing under the paint curtain 10 vibrates for a reason other than the above, the object to be coated 9 mainly vibrates vertically, so the above-mentioned They discovered that defects occur.

Therefore, the inventor of the present invention conducted intensive research on a method for eliminating the above-mentioned defects (color unevenness, ridges) in the coating process using C,'F Coco--. By interposing a stretchable cushioning material between the coating material and the object to be coated, the object can be fully achieved and the present invention has been completed.

That is, the present invention provides a curtain in which the surface of the object to be coated is coated with the paint by causing the paint to flow down in the form of a curtain and passing the object placed on a conveyor under the paint curtain. Coating method using a curtain 70-coater A coating method using a curtain 70-coater, characterized in that coating is performed with an elastic cushioning material interposed between the back surface of the object to be coated and the surface of the conveyor. It is related to.

A feature of the present invention is that during the coating process using the C and F coaters, the coating is performed with an elastic buffer material interposed between the back surface of the object to be coated and the surface of the conveyor (the coating is passed under the paint curtain). ) is there.

As a result, by interposing such a buffer material, C
, Since the vibrations of the object to be coated caused by the above ■ to ■ in the coating process using the F coater are absorbed by the buffer material,
The object to be coated can be conveyed smoothly under the falling paint curtain without vibration, and as a result, all of the above-mentioned defects can be eliminated.

First, the cushioning material used in the present invention and the method for interposing it will be explained.

The cushioning material is used to prevent the object to be coated from vibrating during the above-mentioned coating process, particularly while passing under the paint that is flowing down like a curtain. Therefore, as the cushioning material, it is possible to use a material that has excellent resilience and elasticity, absorbs at least almost all of the vibrations generated by the above-mentioned items 1 to 3, and does not spread the vibrations to the object to be coated. Specifically, foam 7 ohm (foam)
, reticulated foam, etc. are particularly suitable, and in addition to these, elastic rubber, elastic plastic, etc. can also be used, and structures incorporating springs, artificial grass, etc. can also be used. These cushioning materials can be appropriately selected and used in consideration of elasticity, etc., so that the above object can be achieved depending on the size, shape, weight, etc. of the object to be coated.

As a method for interposing these cushioning materials between the back side of the object to be coated and the surface of the conveyor in the C and F coaters, for example, (a) a method of pasting the cushioning material on the back side of the object to be coated in advance; , Place it on the conveyor so that the surface of the cushioning material and the surface of the conveyor are in contact with each other. The jig plate is placed on the conveyor so that the surface of the material is in contact with the surface of the conveyor, and the object to be coated is placed on the jig plate.

(/c) VCM street material may be pasted on the surface of the conveyor in advance and the object to be coated may be placed on the cushioning material, but the present invention is of course not limited to these.

In method (a), the cushioning material may be attached to the entire back side of the object to be coated, but depending on the direction of conveyance of the object (direction of movement of the conveyor), the cushioning material may be applied from the tip of the back side. It is also possible to attach two or more pieces in a line without interruption at the rear end.

FIG. 2 is a perspective view of the cushioning material 13 linearly attached to the back side 12 of the object 9.
Although a specific example is shown in which one tree is pasted on each side of 20, three or more trees may be pasted. You can also wear it.

The object to be coated with the cushioning material 13 attached in this manner is placed on the conveyor 4-1 and subjected to coating by the C and F coaters.

(In the method described above, the jig plate is used to place the object to be coated, and it is difficult or impossible to transfer it smoothly from the conveyor 4-1 of the C and F coaters to the conveyor 4-2. This jig plate is often used when painting objects with large warps or small objects.The method for attaching the cushioning material to the back of the jig plate is the same as in (a) above. Then, the whole surface or " is pasted in a linear manner without interruption. The jig plate with the cushioning material pasted in this way is
Place it on the conveyor 4-1 of the F coater, and then apply the corresponding ? 8. The object to be coated is placed on the board and subjected to painting. Regarding the jig plate, it is preferable that the shape is a flat plate, and its length (in the same direction as the conveyance direction) is, for example, from the tip of the conveyor 4-1 to the conveyor 4-1, based on FIG. It is preferable that the width is about three times or more the length to the rear end of the substrate 2, and the width is preferably the same as or smaller than that of the object to be coated.

In addition, in the method of C), in the same manner as in (a) above, a buffer layer is provided on the entire surface of the conveyor 4-1 and the conveyor 4-2, or intermittently in a linear manner (parallel to the running direction). It is attached without any problem.

In the present invention, a buffer material is interposed between the object to be coated and the conveyance material of the C and F coaters, as shown in (1) to H above, for example, and the thickness of the buffer material is determined by the thickness of the buffer material. It is mostly determined by the elasticity of the material, the weight of the object to be coated (including the jig board), the operating speed of the conveyor, etc., and specifically, 5 m+
~10 cm, especially 5B~3 crn is preferred. Also,
When pasting in a linear form, its thickness and width are also determined by the above requirements, but specifically, the thickness is 5cm to 1cm.
Ocrn, especially 5cm ~ 3cm, width 5n + m ~ 15
crn, particularly 5 ga to 5 σ, is particularly preferred.

In the above (a) to ← in the present method, in G (), the object to be coated has a length that is approximately three times or more the distance from the tip of the conveyor 4-1 to the rear end of the conveyor 4-2. limited to things,
If it is shorter than that, conveyor 4 in C, F cork-
It is difficult to transfer from -1 to conveyor 4-2, and it is necessary to attach cushioning material to each object to be coated, which requires a lot of effort and time. In addition, (/U) greatly reduces the labor and time required to attach the cushioning material, but in addition to the restrictions regarding the length of the object to be coated in (a) above, may adhere to the attached cushioning material, reducing the functionality of the cushioning material.In order to prevent this, if a jig plate with a length longer than that described in (A) above is used in the method (→), , even short objects can be easily coated, and the work of attaching cushioning material is also easy (
b) It is significantly reduced compared to K, and there is almost no paint adhesion to the attached cushioning material. Therefore, in the present invention, any of the above methods (a) to 0) can be employed, but among these, the above method (@) is the most preferred.

Next, the coating method using the C and F coaters according to the present invention is as follows.
This will be explained based on the above-mentioned method using phrases and with reference to FIG.

FIG. 3 shows a C and F coater applying paint to an object 9 using a jig plate 14 on which linear cushioning material 13 is pasted from the tip to the rear end 1 on both sides of the back surface without any markings. It is a side view of the paint being painted.

The six paints sent from the paint tank l to the pouring head 3 by the pump 5 flow down from the slit 7 at the bottom of the head 3 in a thin curtain shape, and then the object to be coated placed on the jig plate 14. The surface of the object to be coated 9 is coated with paint by causing the paint curtain 9 to pass under the paint curtain IO by the operation of the conveyors 4-1 and 4-2.

In the present invention, C and F coaters that are known per se can be used, and there is no particular need to change the mechanism or device. For example, the carrier 4-1 and the carrier 4-
2 is preferably a belt-type or (roller-set) conveyor made of fiber, rubber, or metal.

The paint used in the present invention is not particularly limited as long as it can be coated with a C or F coater, but from the viewpoint of the purpose of the present invention, paints that finish in a colored transparent or colored semi-transparent coating 11 By using a tropical paint, the technical effects of the present invention can be significantly exhibited. Specifically, examples include organic solvent-based, aqueous-based, and non-aqueous-dispersed paints that are cured at room temperature, by heating, or by irradiation with active energy.

The side wall of the paint tank l may be provided with cold water and hot water passages for adjusting the paint temperature, and the bottom of the pouring head 3 has a slit 7 for forming a paint curtain 10. It is preferable to have a structure that allows adjustment in the order of 0 to 4, and the number of heads 3 is usually one (single head type), but it is also possible to install two heads (double head type). As a pouring head, it is also possible to use a set of oats <-70 which does not have a bottom part and allows the paint to overflow from the top in a curtain-like manner.

First, a paint whose viscosity has been adjusted to 15 seconds (Ford Cup #4) or more is sent from the paint tank 1 to the pouring head 3, and when a certain amount is reached, the width (interval) is adjusted to 4 mm or less, preferably 0 mm. The paint curtain 10 is formed by flowing down like a curtain from the slit 7 which is adjusted to have a diameter of 5 to 2 mm. On the other hand, the jig plate 14 on which one or more objects 9 to be coated are mounted is transferred to a conveyor (belt conveyor) 4-IK.
When the object 9 is loaded and the conveyor 4-1 is activated, the object 9 moves forward together with the jig plate 14, passes under the paint curtain 10, and is transferred to the conveyor (belt conveyor) 4-2 provided in front. It is transferred and transported to the next process (for example, thefting, drying process, etc.) by the transport machine 4-2. The speed at which the object to be coated is transported by the conveyor is related to the amount of coating.
For general buttons, a range of 30 to 130 minutes is suitable. In this painting method, since the cushioning material 13 is pasted on the back side of the jig plate 14, the tip of the jig plate 14 is separated from the conveyor 4-1 and is exposed to the conveyor 4 in front. When reaching the rear end of the conveyor 4-2, the tip of the cushioning material 13 comes into contact with the rear end of the conveyor 4-2, so the vibration at that time is absorbed by the cushioning material 13 and It will not spread to. Similarly, vibrations other than those generated during the process of conveying the object 9 to be coated by the conveyors 4-1 and 4-2 are also absorbed by the #straw material 13. Therefore, as a result,
We were able to eliminate all color unevenness and bulges in the paint film caused by vibrations of the object to be coated.

It goes without saying that such technical effects can also be obtained when a buffer material is interposed by methods 0) and 0) above.

Furthermore, the objects to be coated that can be applied in the method of the present invention include C,
There is no particular restriction as long as it can be coated with the F-coater. Specifically, flat plates and square timbers with smooth surfaces made of wood, metal, inorganic materials, plastic, etc. can be coated. It is also possible to coat objects that have a certain degree of curved surface, uneven surface, miso, etc.

Examples and comparative examples related to the present invention are shown below.

Example 1 The object to be coated was an embossed square board (size 6 x 250 x 660, flat plate with embossed linear miso) coated with an undercoat (Rethane IO Sealer #12) and an intermediate coat (P'C Acrylic Intermediate Coat Gray). was used.

As the jig plate, a wooden flat plate with a size of 10 x 150 x 1400 pieces was used, and a flat wooden plate with excellent elasticity and restorability was used as a cushioning material from the tip to the rear end on both longitudinal sides of the back side. Tape-shaped polyurethane-covered foams each having a width of 15 mm and a height of 10 mm were used.

Viscosity 60 as paint applied by C, F coater
1-coat color clear paint (PC Acrylic Color Clear) adjusted to ~80 seconds (Ford Cup 41.4)
was used.

The names of the paints shown above for the undercoat, intermediate coat, and topcoat are all trade names manufactured by Kansai Basito ■.

Two sheets of the above-mentioned objects to be coated are placed side by side in the longitudinal direction and placed on the above-mentioned jig plate, and then transferred to the conveyor (belt conveyor) of the C and F coaters.
I posted it on 4-1. Next, the paint is sent from the paint handle 1 to the boring ring rad 3, and the width of the slotted door at the bottom of the head 3 is adjusted to one throat to allow the paint to flow down.
A paint curtain 10 was formed. Next, jig plate 1
When the transport machine 4-1.4-2 is operated so that the traveling speed of the object placed on the paint curtain 4 becomes 80 m/min, the object to be painted passes under the paint curtain 10, and then the object to be painted passes through the scraper. Transferred to 4-2. When the coated surface of the object coated in this manner was visually observed in detail, no color unevenness was observed, and a finished state with excellent aesthetic appearance was obtained.

Comparative Example 1 Painting was carried out in the same manner as in Example 1, except that a jig plate to which no cushioning material was attached was used. As a result, it was clearly observed that many linear color unevenness occurred on the painted surface of the object in a direction almost perpendicular to the direction of conveyance of the object during painting, and the aesthetics were affected. It was significantly inferior.

Example 2 Application amount of Boliba NC Surf Acer was 40 as the object to be coated.
Birch plywood (10X200X900++m
), and the same jig plate as in Example 1 was used. C,
A two-head type slit type F coater is used, and the paint is polypa enamel black (Polypa enamel black), which has a chisotropic viscosity.
Using B-type viscometer rotor #3, a mixture of 2% by weight of Polyva curing agent D-55 in 7000 centipoise at 6 rpm and 2000 centipoise at 60 rpm was used in the first head, and Polyva curing accelerator C-60 was used. 2% by weight
The prepared mixture was used in the second head.

The above Bolivar NC Sur7 Acer, Polyva Enamel Black, Polyva Curing Agent D-55, and Polyva Accelerator C-60 are all trade names manufactured by Kansai Paint ■.

Two of the above-mentioned objects to be coated were placed side by side in the longitudinal direction on the above-mentioned jig plate, and then placed on the belt conveyor of the C and F coaters. Next, the paint mixed with a curing agent is placed in a first tank, and the paint mixed with an accelerator is placed in a second tank, and the paint is allowed to flow down like a curtain from the slit at the bottom of the head. The conveyor is operated so that the traveling speed of the object to be coated placed on the jig plate is 80 m/min. At this time, 4 from the first paint tank! The coating amount of the curing agent mixed paint sent to the J1 pouring head and flowing down like a curtain was 150 f/m, and the second
The amount of paint containing accelerator that was sent to the pouring head and flowed down like a curtain was 225f/rr? Adjust the amount of paint pumped and the inside of the slit so that

When the coated surface of the coated object coated and dried in this manner was visually observed in detail, a uniform and smooth finish was obtained.

Comparative Example 2 Painting was carried out in the same manner as in Example 2 above, except that a jig plate to which no cushioning material was attached was used. As a result, many line- or band-shaped bulges were generated on the coated surface of the object in a direction substantially perpendicular to the conveying direction of the object during coating, and the smoothness was extremely poor.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the C and F coater, Fig. 2 is a perspective view showing cushioning material attached to both sides of the back side of the object to be coated, and Fig. 3 is a side view showing an example of the coating method of the present invention. It is. In Figures 1 to 3, l: paint tank, 3: pouring head, 4-1 and 4-2: conveyor (belt conveyor), 6: paint, 7: IJ, ), 9: object to be coated,
10: Paint curtain, ll: Paint film, 12: Back side of object to be coated,
13: Cushioning material, 14: Jig plate. Patent Applicant (140) Kansai Paint Co., Ltd. Figure 1 j Figure 2 Figure 3

Claims (1)

[Claims] Let the paint flow down in a curtain shape, and under the paint curtain,
By passing the workpiece placed on the conveyor,
In a painting process ffl using a curtain flow coater that applies the paint to the surface of the object to be coated, painting is performed by interposing an elastic cushioning material between the back surface of the object to be coated and the surface of the conveyor. Curtain flow coater I featuring
c Yoru painting method.