JPH0461959A - Strip coating method - Google Patents

Abstract

PURPOSE:To prevent the edges of a strip from being uncoated by providing the auxiliary rolls having a specific shape before an application roll to impart a high tension to both ends of the strip traveling in the conventional feeding manner. CONSTITUTION:The structure of an auxiliary roll 1 is of the stepped roll 11a having a central small-diametered part 21a of a predetermined width, a large- diametered part 21b at each end thereof and tapering parts 21c therebetween. In a top coating head, a coat is applied by an applicator roll 3 to the surface of a strip 2 supported on a backing roll 1. Another coat can be applied to the rear side of the strip 2 by an applicator roll 4 with the strip 2 maintained under tension by an auxiliary roll 11a or 11b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a roll coating method for a strip, and in particular to a method for uniformly applying a coating liquid from the center of a strip to the edges of the strip. It is something.

(Prior Art) Conventionally, the methods for applying coating liquid such as strip paint have generally been divided into (a) a method of painting both sides completely at the same time, and (b) a method of painting both sides completely at the same time.
) After painting one side, the other side can be painted. In method (a), the strip is supported by a pair of opposing applicator rolls, but in method (b), after painting one side, when painting another side later, the coating film is already on the opposite side. This makes supporting (backing) the strip by a roll from the opposite side impossible.

To explain this with reference to Figure 3, it is composed of two sections, a top coating head A and a bottom coating head B, and each coating head has two to three coater rolls, including an applicator roll that applies paint to the plate. configured.

In the top coating head A, the surface of the strip 2 supported by the backing roll 1 is coated by the applicator roll 3. This can be applied while the strip is supported by a backing roll, so it is not affected by the shape of the strip.
It is easy to coat evenly up to the edges.

On the other hand, in the case of coating in the bottom coating head, the other side has already been coated in the top coating head as described above, so the strip cannot be supported by rolls as in the top coating head.

Therefore, by applying tension to the strip 2, it is pressed against the applicator roll 4.

In coating without such support of the strip by a backing roll, the contact pressure between the strip and the applicator roll is determined by the tension applied to the strip. However, since this method relies on tension, it is easily affected by the width and shape of the strip, and if both sides (or one side) of the strip are stretched vertically, ), the strip and the applicator roll do not come into sufficient contact with each other, causing the problem that both sides (or one side) are not coated (paint film breakage). If the paint film breaks, taking an aluminum can end material as an example, if the paint film break is large, the unpainted part will get mixed into the punched product. Further, even if the coating film is broken to the extent that it falls within the punching allowance, a serious problem arises in that the friction coefficient of the side portions without the coating film is large in subsequent steps, resulting in damage to the machine. On the other hand, although it would be good if a higher tension could be applied to both sides of the strip, changing the specifications of the equipment usually requires large modification costs.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for coating a strip uniformly in the lateral direction when coating one side of the strip. That is, an object of the present invention is to apply a higher tension to both sides of the strip and uniformly coat the edges, without changing the basic specifications of the coater, when the strip is not supported by rolls.

(Means for Solving the Problem) In order to overcome the problems of the conventional coating method, the present inventors installed a roll between the top coating head and the bottom coating head, and determined the shape of the roll and the vicinity of the edge. As a result of extensive research into the relationship between coating removal and generation, we found that by making the roll into a specific shape and applying tension, higher tension is applied to both ends of the strip, allowing uniform coating to the edges, and achieving the purpose. We have discovered that this can be achieved, and have completed the present invention based on this knowledge.

That is, in applying a predetermined coating to one side of a strip using an applicator roll without providing opposing backing rolls or applicator rolls, the present invention provides a method in which both end portions have a larger diameter than the center portion on the applicator roll side in front of the applicator roll. To provide a method for coating a strip, which is characterized in that an auxiliary roll is provided to apply higher tension to both sides of the strip.

The present invention will be described according to an illustrated embodiment.

FIG. 1 is a side view of a coating apparatus for carrying out the coating method of the present invention.

In front of the bottom coating head B, an auxiliary roll 11, which will be described in detail with reference to FIG. 2, is installed, the shaft diameter of which is larger at both ends than at the center. In the bottom coating head B, the strip 2 is surface coated with an applicator roll 4. The coating liquid 6 in the coater pan 5 is transferred to the applicator roll 4 via a pickup roll 7 and a metering roll 8. Top coating head A
The coating itself is the same as in Figure 3, and the same symbols as in the figure indicate the same things, 9 is the coating liquid, 10 is the coater pan,
12 is a pickup roll, and 13 is a metering roll.

The structure of the auxiliary roll 11 used in the present invention is shown, for example, in FIGS. 2(A) and 2(B). Second (A
) The one shown is a stepped roll 11a, which has a small diameter part 21a at the center having a constant width, large diameter parts 21b at both ends, and a tapered part 21c between them. The one shown in FIG. 2(B) is a crown roll llb, in which the outer edge of the central portion is circular arc-shaped and forms a crown portion 21d with respect to large diameter portions 21e at both ends. In the figure, D is the center roll diameter in Figure 5(A) or the minimum diameter of the crown part in Figure 5(B), D2 is the roll diameter at both ends, and Ll is the center roll diameter in Figure 5(A). The length, Ll, is the total length of the roll portion and the tapered portion in Fig. 5(A), L.
, indicates the length of the crown portion in FIG. 5(B).

In the auxiliary roll used in the present invention, Da-D is
It varies depending on the strip width, strip shape, etc.
2 mm or more is preferable, and 5 to 8 mm is more preferable. Strip width and Ll, L.

The relationship between (L, ) varies depending on the stepped amount (crown amount), but W-Ll is preferably 20 to 100 mm, and 40 to 60 mm.
mm is more preferable. L, -W (L, -W) is 20 to 1
00 mm is preferable, and 40 to 60 mm is more preferable.

The tension may be at a level that does not cause problems in threading such as roll slip, but it is preferable that the tension be as high as possible.

In coating using the apparatus shown in FIG. 1, in the top coating head a strip 2 supported by a backing roll 1 is surface coated by an applicator roll 3. Next, an auxiliary roll l as shown in FIG.
Applying tension to the strip 2 by la or llb,
The back side of the strip 2 can be coated by means of an applicator roll 4.6 Other than the above, the coating method is the same as before.

The vine strip to which the method of the present invention is applied is an aluminum plate, an aluminum alloy plate, a steel plate, etc. In the present invention, the line speed of the strip is not particularly limited. The coating liquid may be any one used in a roll coater, and is not limited thereto.

(Example) Next, the present invention will be explained in more detail based on examples.

Example Using the apparatus shown in FIG. 1, double-sided coating of an aluminum alloy plate strip was carried out under the following conditions.

Conditions Line speed 100 m/min Coating liquid Epoxy paint target coating amount
Weight after drying: 3.5 g/m" Aluminum alloy plate strip dimensions: 0.25t x 900Wmm Here, as an auxiliary roll, 11a (type A) or 1l
Experiments were conducted using Type B (Type B) with different specifications and by changing the coater tension.

For comparison, experiments were also conducted in the case where the coater tension was kept constant, the auxiliary roll 11 was omitted, and the diameter was replaced with a straight roll. The results are shown in Table 1.

(Effects of the invention) In the present invention, by installing an auxiliary roll of a specific shape in front of the applicator roll, it is possible to apply higher tension to both ends of the strip while maintaining the conventional threading state. It is possible to prevent the problem of not being The method of the present invention has extremely great industrial value not only in improving the quality of products, but also in improving yields and preventing damage to machines.

[Brief explanation of the drawing]

Fig. 1 is a side view of one embodiment of the coating device used in the method of the present invention, Figs. 2(A) and 2(B) are side views of the auxiliary roll in the method of the present invention, and Fig. 3 is a conventional coating method. equipment 1
It is a side view which shows an example. Figure 2 (A)

Claims (1)

[Claims] (1) When applying a predetermined coating to one side of the strip using an applicator roll without providing an opposing backing roll or applicator roll, both ends are made larger in diameter than the center part on the applicator roll side in front of the applicator roll. A method for coating a strip, characterized in that an auxiliary roll is provided to apply tension to the strip.