JPH01200247A - Method and device for coating - Google Patents

Abstract

PURPOSE:To prevent generation of a stripe trouble by using a slide hopper device combined with a lip-shaped part and a liquid end holding part in a required manner for bead coating by the slider hopper. CONSTITUTION:The lip-shaped part 15 having the angle of inclination with horizontal smaller than the angle of inclination of the sliding surface of the slide hopper is provided to the bottom end of the sliding surface and the liquid holding part 16 is provided to the contact rear end part of a bead 12 with the hopper device. A liquid thickness is increased in the lip-shaped part 15 by combination of the lip-shaped part 15 and the holding part 16, by which the bottom end of the bean 12 is reinforced and stabilized and the generation of the stripes occurring in sticking of dust to the coating start point and joint of webs 10 is prevented. The bead is stabilized and the generation of the stripes is prevented even in the case of the low-viscosity and low-flow rate bead.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a substrate coating method and apparatus for applying one or more coating liquids to a substrate to be coated using a slide hopper device. The present invention relates to a coating method and apparatus suitable for manufacturing photographic materials.

[Prior Art] Conventionally, in order to apply one or more coating liquids in one or more layers to a substrate to be coated such as a support of a photographic light-sensitive material using a slide hopper device, US Pat. No. 2,761,419 and US Pat.
As described in No. 61791, etc., a substrate to be coated with a photographic light-sensitive material is run facing the coating liquid outlet end of a slide hopper or an extrusion hopper device, and one or more emulsion-like coating liquids are flowed out from the coating liquid outlet end. It is also known to form a bead at least on the entry side of the substrate to be coated, which is behind the coating liquid outlet end of the hopper device. .

However, according to these conventional techniques, if the bead is disturbed or stirred, or if the multilayer coating interface is disturbed by foreign matter such as dust, various effects may occur on the coating layer formed on the substrate by coating the coating liquid. For example, a particularly noteworthy defect is the occurrence of a streak failure that appears in the direction of 11 (. This streak 1+g occurs when the amount of coating is applied, or when the substrate to be coated passes through the coating, or when foreign matter such as dust is attached to the substrate even during steady coating. In this case, there are some things that occur when this foreign object passes through.Then, this streak failure occurs at a high rate of application or N-VII'J application.In order to prevent the occurrence of the above-mentioned streak failure. Various improved techniques have been proposed as techniques for this.For example, (1) U.S. Pat.
681294, by creating a vacuum on the surface on which sweat is suspended, bead''-
A technique that creates a pressure difference (hereinafter simply referred to as the degree of reduced pressure) between the exposed surfaces below, (2) applying an oil-based hydrophobic substance to the JP Publication No. 47-7L No. 27.25, or forming it on the rear edge of the joint. (3) As disclosed in Japanese Patent Publication No. 48-4371, water is applied to the rear edge of the joint in order to attach water to the joint of the coated substrate. Technique for spraying or applying (4)
) As disclosed in Japanese Patent Publication No. 51-39980,
A lip is provided at the coating liquid outflow end of the hopper device, and the inclination angle of the top surface of the lip is smaller than the inclination angle of the coating liquid outflow surface, so that the thickness of the coating liquid layer on the top surface of the lip is formed. In addition, in this technology, the tip edge of the lip is rounded or chamfered in order to prevent streak failures that occur due to the sharpness of the tip edge of the lip. (5) Special Public Service 1986-1990
As disclosed in No. 7, in order to stabilize the rear end of the bead in contact with the hopper, a technique has been proposed in which a liquid end holding part, which is a coating liquid reservoir, is provided. However, even with the above-mentioned techniques, the current situation is that they are still not sufficient as countermeasures against streak failures.

For example, the technique (4) above is effective to some extent against streak failures caused by dust particles in the coating liquid, but is not effective against streak failures that occur at the leading edge of coating or at joints. Also, the effect is small when the amount of liquid flowing on the slide surface is small, which is flff; AJ'[
Providing a lip-shaped portion of ff;l has the effect of thickening the liquid layer in this portion, and has the effect of minimizing the influence of disturbance caused by foreign particles such as dust adhering to this portion. As the inclination of the lip becomes lower, the stability at low flow rates deteriorates, perhaps because of the instability of the bead due to the drop in dynamic pressure flowing down the slide surface edge (referred to as the lip). According to the technique 5), it is effective for removing streaks at the beginning of coating and at joints, but in the case of low viscosity liquid coating, the appropriate degree of vacuum is lowered, but the effect of increasing the stability of the bead is not sufficient.

In recent years, there have been severe demands on photosensitive materials, and in particular, high-speed, thin-film coating has become increasingly necessary in order to improve sharpness, but the above-mentioned conventional techniques alone cannot sufficiently meet these demands.

[Problems to be Solved by the Invention] In order to solve the problems such as the above, it is an object of the present invention to provide a coating method and apparatus that do not cause streak failures either at the start of coating or when passing through the joint. It is to be. Still another object of the present invention is to provide a coating method and apparatus that are unlikely to cause streak failures even when the viscosity is low and the flow rate is low.

[Means for Solving the Problem] The above-mentioned object of the present invention is to arrange and form a lip at the downstream end of the slide surface in a bead coating method using a slide hopper device, and to form a lip on the upper surface of the lip. The bead angle is set to be smaller than the inclination angle of the slide surface, and a coating reservoir for holding a coating film is provided at the rear end of the bead in contact with the hopper device, and the rear end of the bead is This is achieved by a method of coating a substrate, characterized in that the liquid is applied while being held in contact with the liquid edge holding part, and a slide hopper device characterized in that it has the lip-shaped part and the liquid edge holding part.

The present invention will be explained in more detail below.

Various factors can be considered to be the cause of the streak failure, but the main reason is likely to be the disturbance of the interface during multilayer coating. Such disturbances may be caused by foreign particles such as dust or ponds, or by the substrate being coated or splicing tape,
This may be caused by wetting of the lower layer and the coating liquid.

In the sliding bead coating method, the stability of the bead is fundamentally important. Coating conditions are determined by appropriately combining these requirements, but as mentioned above, recent requests for photosensitive materials 4'-[
Conditions that deviate from the conventional range are becoming necessary.

In the present invention, a slide hopper device having the lip-shaped portion and the liquid end holding portion is used, and it has been found that this combination has an effect that cannot be expected from the effects of each method.

In other words, according to the present invention, stable coating can be performed even with a coating liquid of low viscosity and low flow rate, making it possible to meet the recent strict demands for photosensitive materials.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an example of a slide hopper device for two layers used in the present invention.
The emulsion liquid passes through the pipe 14, flows down the slide surface 5 while holding the two layers, reaches the lip part 6, and connects to the web 10, which is the substrate to be coated, which is carried by the coating pack arrangement 10-1. A bead 12 is formed in between. Note that the bead is pulled downward by the pressure reducing device 3 to improve stability.

2 to 5 are enlarged sectional views of the vicinity of the lip portion 6, which is the front edge of the slide hopper device. In these figures, 5 is a sliding surface, 6 is a lip part, 15 is a lip-like part, and 16 is a liquid end holding part, respectively. FIG. 2 is a cross-sectional view showing the shape of the lip-like part, FIG. 3 is a sectional view showing the shape of the liquid end holding portion. FIG. 4 is a cross-sectional view of the present invention having both a lip-shaped portion and a moat end holding portion.

In the figure, (a) to (e) are examples showing various implementations of the present invention, but the present invention is not limited to these. FIG. 5 is a cross-sectional view showing the state of the bead during coating for explaining the present invention in detail. In the figure, 10 is a web, 11 is a coating film, 12 is a beat, ]3.
14 represents two layers of coating liquid flowing on the slide surface. Same figure (
A) shows the state of the conventional bead, while FIG. The bead stability is not improved because the bead stability is not improved because the bead stability is not improved. (d) is the case of the present invention, but in this case, in addition to stabilizing the lower end of the bead, the liquid film at the lip becomes thicker, making the bead significantly stronger. . Zunahachi (
As can be seen in the example of b), the bead becomes shallow in the lip-like part (b), but simply increasing the degree of decompression will make it unstable.
By providing the lower end holding portion, it is possible to set the degree of vacuum that stabilizes the lower end.

The effects of the present invention will be specifically illustrated by Examples below.

[Example] Example 1 A halogen monoarsenic photographic emulsion consisting of 4WI,
A halogen-1 silver arsenic photographic emulsion with a 120 μm thick under-dragging triacedate base as a coated substrate, a silver halide photographic emulsion having a different color sensitivity from the first layer in the second layer, 3
The second layer was a non-photosensitive gelatin middle layer, and the second layer was a gelatin protective layer, which were simultaneously layered using the following slide hopper devices. The slide hopper devices used are (a) to (ii) shown in FIG. 5.

Coating conditions are coating speed 15 0 +a/win, total weight i
The coating liquid viscosity was 130 g/m2 and 19 cp.

The coating results are shown in Figure 6 (a) as the number of streaks from the beginning of coating.
It was shown to. According to this result, the result of having only a lip-shaped part (mouth) is slightly better than the normal one without any processing (a), but on the other hand, the results of c) and (ii) are excellent. showed that. In this case, this is due to the effect of the holding part on the liquid 1 at the lower end of the bead. Note that - is the case from the beginning of coating, but the same results were obtained at the joints.

Example 2 Basically, 180B+n bottom drag polyethylene terephthalate was used, and gelatin was coated as the bottom layer.
A protective layer was simultaneously coated with two layers of a 1-cogen-1-arsenic photographic emulsion as an inder. The coating conditions were coating (l
i eff1 degree 8011I/min, coating liquid specific gravity Ji1
．． 50 g/m2, coating liquid viscosity 9cl+, e1! The coating machine and the total result 1i11i are as in Example 1.
is the same as

The results are shown in Figure 6 (1+), in which (b) is (
It is the same or lower than b). Also, although (c) has a smaller effect, it is not sufficient.
d) shows that (b) and (c) alone produce an effect that cannot be predicted.In cases where the viscosity is as low as in this example and there are few types of application, the lips alone are not effective and the liquid Although the effect of stabilizing the bead due to edge retention is poor, the method of the present invention is recognized to have a particularly excellent effect. In this example, similar results were obtained at the joint portion.

Example 3 The same acid coating basics, coating liquid, and coating (L) as in Example 2 were used, coating speed was 1.OO+11/pongee in, coating liquid viscosity was 9 cp, coating liquid specific gravity ML was 45 g/m2, and the same as in Example 2. The coating speed was faster with a ratio of 111Q.The results were evaluated in the same manner as in Example 1 and are shown in FIG. 6(c).

In this example, in case (b), the beat was unstable and it was destroyed.

In this example, it is effective in case (c), but it is effective in case (d).
Similar results were obtained at the joint portion even in the case of 0, which was an inferior result.

1. As is clear from the results of Examples 1 to 3, the lip-shaped part has a slight effect under normal coating conditions, but with low viscosity and low flow rate 1, the beat is unstable, and even at high speeds. It became impossible to apply.

Although the effect of the residue end holding part is considerably recognized, it is insufficient in the case of low viscosity, low flow (2), and even high speed. In contrast to these, in the case of the present invention, excellent results could be obtained.

[Effects of the Invention] According to the present invention, streak failures do not occur in slide bead coating either at the start of coating or when passing through the joint, and furthermore, streak failures are less likely to occur even in the case of low viscosity, low flow rate, and high speed. We were able to provide a coating method and device.

[Brief explanation of the drawing]

Figure 1 shows one of the slide hopper devices used in the present invention.
FIG. 3 is an example cross-sectional view. 2 to 5 are enlarged sectional views of the vicinity of the lip portion of the slide hopper device of the present invention. f:
Figure tIJ6 is a diagram showing the results of the example. 1: Coating backup roll 2: Slide hopper device

Claims (2)

[Claims] (1) In a bead coating method using a slide hopper device, a lip is arranged and formed at the downstream end of the slide surface, and the angle of inclination of the upper surface of the lip with respect to the horizontal is smaller than the angle of inclination of the slide surface. Further, a coating reservoir part for holding the coating film is provided at the rear end of the bead in contact with the hopper device, and coating is carried out while the rear end of the bead is held in contact with the liquid end holding part. How to apply the substrate. (2) In a slide hopper device that applies one or more coating liquids to a moving substrate to be coated, a lip-shaped portion is arranged and formed at the downstream end of the slide surface, and the upper surface of the lip-shaped portion is inclined with respect to the horizontal. A slide hopper device, characterized in that the angle is set to be smaller than the inclination angle of the slide surface, and a liquid end holding portion is further provided to hold the rear end of the bead in contact with the hopper device.