JPS61161182A - Coating method of seam part on can inside - Google Patents

Abstract

PURPOSE:To coat the inside of the groove in the crevasse of the seam part in the inside bottom of a one-end seam can under rotation to form a thoroughly coated film with a small amt. of paint by discharging directly the paint from an extrusion nozzle from the outside of the aperture of said can. CONSTITUTION:The paint for can making is approximately linearly discharged by the extrusion nozzle EN from the outside of the aperture of the can and is coated along the inside groove faces 3C, 4C of the crevasse C of the inside seam part in the base of the can under rotation. The inside of the groove in the crevasse of the seam part in the bottom of the can is thus thoroughly coated with the small amt. of the paint and the thorough covering effect is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coating the bottom inner seam of 3PC cans.

Conventionally, when it comes to painting the inside of 3pc (cans consisting of 6 parts: body, bottom, and lid) type cans, one-end seam coating is applied using either the lancing method (the can rotates and the spray nozzle is fixed) or the stationary method (the can rotates and the spray nozzle is fixed). The spray nozzle was fixed and the spray nozzle rotated).

However, in the conventional internal coating described above, especially when coating crevices at seams, as shown in Figure 1,
Since the crevasse C is narrow, deep, and horizontally long in a ring shape, the air A is trapped in the groove of the crevasse, and a bridge B is formed by the coating film. , injected paint S in the spray direction.

S hit the inner groove surface of the crevasse, and the reflection caused an uneven sound.
R2), this caused problems such as air bubbles getting inside the adhered paint.

In addition, the brim-like coating film B after curing is fragile and easily damaged by drop impact, etc., and the contents enter the air space inside the crevasse through these damaged parts, causing the core to corrode. There were also some negative effects.

Originally, paint must be able to enter the interior of the above-mentioned crevasse. This is because when seaming a can lid and a can body, scratches are likely to occur particularly where the two overlap, which poses a major problem as described above.

Applying too much paint will not only waste paint, but also cause blisters, blisters, etc. in the seam area.
This tends to cause bubbles and the like, and at the same time, the penetration of the paint into the crevasse described above depends on its own weight, which is extremely unstable. Furthermore, many disadvantages were observed, such as increased setting time and decreased product quality and aesthetics.

The object of the present invention is to completely coat the inside of the crevasse in the seam at the bottom of the can with a small amount of paint, thereby achieving a complete covering effect.

The gist of the present invention is to linearly discharge paint from outside the can opening of a rotating one-end seam can using an extrusion nozzle, and apply a small amount of paint along the inner groove surface of a crevasse. This is a method of doing this.

Note that extrusion nozzles are used for liquid purposes. Please refer to Figure 6. The can is rotating around can axis X. Fixed extrusion nozzle EN installed outside the opening of the section
The paint is discharged (sp). This paint is opened and closed by a special gun G, and a certain hydraulic pressure is applied to the gun G, and it is discharged from an extrusion nozzle EN attached to the gun, and its shape is assumed to be relatively straight. It is said that The reason for this is that, as shown in Fig. 4, on the inner groove surfaces 3C and 4C on both sides forming the crevasse C,
When the discharged paint collides, as in the conventional case described above,
This is to avoid collision with the inner groove surface as much as possible, that is, to aim only at the space of the crevasse C, and spray the paint, since the paint film becomes thick in unnecessary places. Therefore, the paint SP discharged from the extrusion nozzle EN provided on the outside of the can opening is linearly 5 degrees, and parallel to the inner surface of the body 3 in this area. It is desirable that it be discharged.

In addition, the linear paint is applied pointwise and continuously to the inner groove of the crevasse C, that is, the ring-shaped inner groove, and as in the past, it is applied by a spreading layer. Unlike surface application, it is impossible for air to be trapped within the crevasse.

As described above, according to the method of crevasses coating using a linear discharge flow of paint from an extrusion nozzle according to the present invention, the voids of the crevasse can be filled without enclosing air and only the voids of the crevasse can be coated. Furthermore, with a small amount of paint, the desired sealing layer can be formed without the inclusion of air bubbles.

In addition, after applying the above-mentioned seam rebus,
As a car, it is necessary to coat the inside of the can.

These latter coating operations are conventionally carried out by Ayumu Misu. That is, method 1 is a method in which the inner bottom of the can is coated first (FIG. 5), and then the body is coated (FIG. 6). Next is a second method in which the above coating order is reversed, first coating the can body (FIG. 6) and then coating the can bottom (FIG. 5). The final method is a third method in which the coating is applied to the can body and the can bottom at the same time (FIGS. 7 and 8).

As mentioned above, these methods are carried out in combination with crevasse coating on the seam portion.

Finally, we will discuss how to apply rebus to the seam on cans that do not require internal relapsing.

Can paint is used as the paint, and as in the case described above, the paint is discharged almost linearly from an extrusion nozzle using the stationary method to coat the inside of the crevasse. What happens next is different from the conventional case described above. That is, as shown in FIG. 9, the seam portion is locally heated from the outside of the can. As the heating method, any of the hot air method, electric heating method, high frequency method, etc. can be applied.

As described above, according to the method of applying crevasse at the seam inside a can according to the present invention, air is not enclosed in the crevasse, and therefore, the paint film does not bleed or splat. A solid, strong coating layer can be formed without introducing air bubbles, and the purpose of coating can be fully achieved using the minimum amount of paint necessary for forming the coating layer.

[Brief explanation of the drawing]

Figure 1 shows a conventional application method for rebusing the bottom seam inside a can. Figure 2 is an illustration of the generation of turbulence in the above method.
Fig. 3 is an explanatory diagram of the coating method using the extrusion nozzle according to the present invention. Fig. 4 is an enlarged view of the E” section in Fig. 3. Fig. 5 is an explanatory diagram of the application of the inner surface of the bottom after coating the seam portion according to the present invention. The figure is also a diagram explaining the application of the inner surface of the body.
Figures 7 and 8 are illustrations of simultaneous coating on both the barrel and bottom. Figure 9 is an illustration of heating the can paint from the outside of the diameter when the inner surface of the can is not required. Explanation of the main symbols.

Claims (1)

[Claims] 1. Can-making paint is applied in a substantially straight line along the inner groove surface of a crevasse in the inner seam of the bottom of a rotating can from outside the opening of the can using an extrusion nozzle EN. A method for coating the inner seam of a can, which is characterized by coating by discharging (FIG. 3). 2. Dispense can-making paint almost linearly from the outside of the opening of the can along the inner groove surface of the crevasse in the inner seam of the bottom of the rotating can using the exfusion nozzle EN. (Fig. 5) and then the bottom 4A (Fig. 5) or body 3B (Fig. 6) of the can, followed by the body 3B (Fig. 6) or bottom 4A (Fig. 5), or Bottom part 4D and body part 3
A method for coating the inner seam of a can, characterized in that D is coated on the inner surface at the same time (FIG. 7 or 8). 3. For cans that do not require relacquer, apply can-making paint in a nearly straight line from outside the opening of the can along the inner groove surface of the crevasse at the inner seam of the bottom of the rotating can. A method for coating the inner seam of a can, which comprises discharging the coating onto the can (FIG. 3) and then locally heating the can from the outside (FIG. 9) to cure the can.