JP3316647B2 - Multi-layer simultaneous application method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a multi-layer slide bead having 11 or more layers simultaneously or a method for applying a curtain having a slide surface, and more particularly to the production of a color photographic light-sensitive material.

[0002]

2. Description of the Related Art In recent years, techniques relating to a multi-layer simultaneous coating method comprising a plurality of layers have been highly developed in connection with the production of silver halide photographic materials requiring many thin layers. As such a multilayer simultaneous coating method, a coating method using a slide hopper or a curtain coater is adopted as a preferable method. In the slide hopper method or the curtain coater, from the viewpoint of improving production efficiency, any number of simultaneous coating layers is controlled. Is one of the issues.

However, if the number of simultaneously applied layers is to be increased, ripples and inter-layer mixing on the slide surface of the coating apparatus are liable to occur, making it difficult to perform good coating. It has been extremely difficult to obtain a uniform coated surface state with non-uniform color density, that is, without color unevenness. Therefore, conventionally, in the production of a color photosensitive material having a large number of coating layers, especially 11 or more layers, it is common to apply the coating in two or more times.

On the other hand, JP-A-3-219237 discloses that the viscosity of the lowermost layer (15 to 100 cp) and the viscosity of the other layer (30 cp or more, average 60
~300cp), each layer of the coating amount total coating amount of 3 cc / m ² to 300
An application method is proposed in which the content is not more than cc / m ² to prevent color unevenness and interlayer mixing. However, color unevenness and interlayer mixing often occur even when the coating is performed using only the method of defining such viscosity and film thickness. In particular, when 11 or more layers are simultaneously coated, this range is not sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art by simultaneously applying 11 or more layers to form a uniform coating surface free from color unevenness caused by waves on the slide surface. An object of the present invention is to provide a multi-layer simultaneous coating method which can be obtained and has high productivity.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a multi-layer simultaneous coating of 11 or more layers using a slide bead coating device or a curtain coating device having a slide surface on a continuously running support. For the velocity component parallel to the sliding surface of the falling liquid film above, above the liquid-liquid interface,
This is achieved by the coating method of the multilayer simultaneous coating method, wherein the lower shear rates _du and _dl and the flow time t at the interface are ( _du + _dl ) / 2 × t ≦ 250.

The multilayer simultaneous coating method of the present invention is effectively and desirably used for producing a photosensitive material, particularly a silver halide color photographic photosensitive material.

Hereinafter, the present invention will be described specifically.

FIG. 1A shows a slide bead coating apparatus 1.
FIG. 4 is a cross-sectional view illustrating an example, which is a coating apparatus capable of simultaneously coating two layers. In the figure, a plurality of coating liquids 13 and 14 reach a slide surface 5 through a pocket 7 and a slit 4 which spread in the width direction, and the coating liquid flows down the slide surface to reach a tip (lip) 6 of a coating machine. A web that runs while being held by the backup roll 1 through a liquid pool called a bead 12
Applied on 10. FIG. 3 shows a pressure reducing device for stabilizing a bead by pulling the bead downward.

FIG. 1A shows the case of two layers. However, when performing simultaneous coating of 11 layers or more, the number of coating blocks may be increased. Therefore, the number of slits is 11 or more, the number of slide surfaces is increased, and the liquid overlap is increased. The number of superimposed layers of the coating liquid on the slide surface increases gradually from the upstream side, and at the most downstream (slide surface near the lip), 11 or more liquid layers overlap, which causes turbulence and ripples between the liquid layers. Easier to do.

FIG. 1B shows a state in which the coating solutions S ₃ , S ₂ , and S ₁ flowing out of the slits are overlapped on the slide surface. As can be seen from the figure, the coating solution on the upstream side, for example, S
Numeral ₃ flows as a layer while passing over the coating solution S ₂ on the downstream side and further over S ₁ .

The inventors of the present invention have conducted intensive studies on the problem of color unevenness and interlayer mixing caused by the waves on the slide surface. As a result, the apparatus conditions are as follows. It has been found that it is effective to provide (notches), and the applicant has disclosed it in Japanese Patent Application No. 4-328174.

When the coating liquid flowing on the slide surface comes into contact with the web via the bead, the influence of the inclination angle of the slide surface with respect to the horizontal reference plane is also important. FIG. 1C is a cross-sectional view showing the relationship between the slit and the slide surface. The angle θ between the slide surface and the horizontal reference plane in FIG. The ripple phenomenon is mainly governed by the coating liquid film thickness (flow rate) on the slide surface and the flow time at the liquid-liquid interface. In the present invention, the inclination angle is preferably 5 to 30 °,
More preferably, it is 5 to 25 °, most preferably 10 to 20 °. If the angle is 5 ° or less, the falling time increases, and if the angle is 30 ° or more, the flowing liquid film thickness becomes small, and the waving phenomenon easily occurs.

It is preferable that the angle between the slide surface represented by β in FIG. 1C and the extension of the slit is 90 ° or less.

FIG. 1C is a sectional view showing an example in which a step is provided on the exit side of each slit except for the slit for the uppermost layer. The step Δh is 0.1 to 5 mm and varies depending on the desired wet film thickness, but is preferably 0.2 to 3 mm.

With such a structure, liquid disturbance due to collision between the coating liquids at the slit outlet can be suppressed.

The slit gap can be set arbitrarily in the range of 50 to 1000 μm.

By providing an enlarged portion (notch) E at the slit outlet as shown in FIG. 1C, the discharge pressure when the coating solution flows out of the slit outlet to the slide surface is reduced, and Liquid turbulence for the coating liquid is suppressed.
According to the study of the present inventors, there is a difference in the pressure distribution near the slit exit due to the shape of the slit, and by providing the enlarged portion in the slit, the pressure distribution becomes uniform, thereby suppressing waving. Was found. When the magnification is 2 or more, the effect is remarkable. Note that the same effect can be expected regardless of whether the enlarged portion is provided in the coating block on the downstream side or the coating block on the upstream side of the slit.

The present inventor has further paid attention to the viscosity balance between the layers, and the applicant has specifically presented in Japanese Patent Application No. 4-346189 the viscosity balance and the viscosity difference between the adjacent layers and the intermediate layer.

However, these equipment conditions and viscosity,
The density, the flow rate, and the like affect each other, and as a result of intensive studies, the present inventors have created a parameter Y integrating these. That is, Y = f (flowing distance L, angle θ, flow rate, viscosity, density), and assuming a two-dimensional parallel flow, solve the Navier-Stokes equation of motion in the xy coordinate system shown in FIG. , The shear rate (upper layer side and lower layer side) and the interface speed at the liquid-liquid interface are determined.

The case of the two-layer flow shown in FIG. 2 (a) represents the flow of the coating solution of the slide surface in the case of two layers. In the same figure, the upper layer coating liquid 2 coming out of the first slit reaches the coating machine end while overlapping the lower layer coating liquid 1 coming out of the second slit, and is simultaneously coated on the web running while being held by the backing roll. You. L represents the distance from the second slit to the end of the coating machine, and d ₂ and d ₁ represent the thickness of the coating solutions S ₂ and S ₁ flowing simultaneously on the slide surface. Is the angle between the slide surface and the horizontal plane.

The parameter Y is calculated by the following equation.

[0023]

(Equation 1)

In the case of the n-layer flow diagram. 2 (b) in the case of the n-layer, the coating liquid S _{k + 1} in this case, out of the S _k solution and slits k + 1 generated from the slits k
In the area L _k where the S _k liquid is in contact with the slide surface, the shear rate is calculated, and the flow time is S _k −S
_The parameter Y is calculated by calculating the time required from the formation of the _{k + 1} interface to the application.

In this way, Y can be calculated for all the interfaces.

In the present invention, the flow rate at the slit outlet in all the coating layers is preferably 0.1 ml / cm / sec or more, and the coating speed is set in the range of 30 to 600 m / min. Preferably, a speed of 40 to 400 m / min, more preferably 60 to 250 m / min is employed.

The support used in the present invention is a transparent support such as polyethylene terephthalate or triacetyl cellulose, a reflective support such as polyethylene laminated paper, etc., and is not limited to a specific support.

[0028]

EXAMPLES The effects of the present invention will now be specifically illustrated by examples.

With respect to the coating layer in the present invention, the following 15
Layer formulation was used as a reference.

Incidentally, the amount of the composition added is expressed in grams per 1 m ² unless otherwise specified. Silver halide and colloidal silver are shown in terms of silver. The sensitizing dye was represented by the number of moles per mole of silver halide.

The viscosity was adjusted with an aqueous thickener containing styrene and a maleic acid sodium salt copolymer as main components.

(Preparation of 15 layers) First layer: Antihalation layer Black colloidal silver 0.16 Ultraviolet absorber (UV-1) 0.20 High boiling solvent (Oil-1) 0.16 Gelatin 1.23 Second layer: Intermediate layer Compound (SC-1) 0.15 High-boiling point solvent (Oil-2) 0.17 Gelatin 1.27 Third layer: low-sensitivity (first) red-sensitive layer Silver iodobromide emulsion (average grain size 0.38 μm, silver iodide content 8.0 mol%) 0.50 (average) Particle size: 0.27 μm, silver iodide content: 2.0 mol%) 0.21 sensitizing dye (SD-1) 2.8 × 10 ^-4 sensitizing dye (SD-2) 1.9 × 10 ^-4 sensitizing dye (SD-3) 1.9 × 10 ^-5 sensitizing dye (SD-4) 1.0 × 10 ^-4 cyan coupler (C-1) 0.48 cyan coupler (C-2) 0.14 colored cyan coupler (CC-1) 0.021 DIR compound (D-1) 0.020 High boiling point solvent (Oil-1) 0.53 Gelatin 1.30 Fourth layer: Medium-sensitivity (second) red-sensitive layer Silver iodobromide emulsion (average particle size 0.52 μm, iodine Silver content of 8.0 mol%) 0.62 Silver iodobromide emulsion (average grain size 0.38 .mu.m, a silver iodide content of 8.0 mol%) 0.27 Sensitizing dye (SD-1) 2.3 × 10 -4 Sensitizing dye (SD-2 1.2 × 10 ^-4 sensitizing dye (SD-3) 1.6 × 10 ^-5 sensitizing dye (SD-4) 1.2 × 10 ^-4 cyan coupler (C-1) 0.15 cyan coupler (C-2) 0.18 colored cyan Coupler (CC-1) 0.030 DIR compound (D-1) 0.013 High boiling point solvent (Oil-1) 0.30 Gelatin 0.93 Fifth layer: high sensitivity (third) red-sensitive layer Silver iodobromide emulsion (average particle size 1.00 μm) 1.27 Cyan coupler (C-2) 0.12 Colored cyan coupler (CC-1) 0.013 High boiling solvent (Oil-1) 0.14 Gelatin 0.91 Sixth layer: Intermediate layer Compound (SC-1) 0.09 High boiling point solvent (Oil-2) 0.11 Gelatin 0.80 7th layer: Low sensitivity (1st) green-sensitive layer Silver iodobromide emulsion (average grain size 0.38 m, silver iodide content 8.0 mol%) 0.61 Silver iodobromide emulsion (average particle diameter 0.27 [mu] m, silver iodide content 2.0 mol%) 0.20 Sensitizing dye (SD-4) 7.4 × 10 -5 Sensitizing dye (SD-5) 6.6 × 10 ^-4 Magenta coupler (M-1) 0.18 Magenta coupler (M-2) 0.44 Colored magenta coupler (CM-1) 0.12 High boiling solvent (Oil-2) 0.75 Gelatin 1.95 Eighth layer: Medium-speed (second) green-sensitive layer Silver iodobromide emulsion (average grain size 0.59 μm, silver iodide content 8.0 mol%) 0.87 sensitizing dye (SD-6) 1.6 × 10 ^-4 sensitizing dye (SD- 7) 1.6 × 10 ^-4 (SD-8) 1.6 × 10 ^-4 magenta coupler (M-1) 0.058 〃 (M-2) 0.13 Colored magenta coupler (CM-2) 0.070 DIR compound (D-2) 0.025 DIR compound (D-3) 0.002 High boiling solvent (Oil-2) 0.50 Gelatin 1.00 Ninth layer: High sensitivity (third) green-sensitive layer Silver iodobromide emulsion (average Diameter 1.00 .mu.m, a silver iodide content of 8.0 mol%) 1.27 Sensitizing dye (SD-6) 9.4 × 10 -5 Sensitizing dye (SD-7) 9.4 × 10 -5 〃 (SD-8) 9.4 × 10 - ⁵ Magenta coupler (M-2) 0.084 〃 (M-3) 0.064 Colored magenta coupler (CM-2) 0.012 High boiling solvent (Oil-1) 0.27 High boiling solvent (Oil-2) 0.012 Gelatin 1.00 10th layer: Yellow Filter layer Yellow colloidal silver 0.08 Color stain inhibitor (SC-2) 0.15 Formalin scavenger (HS-1) 0.20 High boiling solvent (Oil-2) 0.19 Gelatin 1.10 11th layer: low sensitivity (1st) blue-sensitive layer Silver iodide emulsion (average particle size 0.38 μm, silver iodide content 8.0 mol%) 0.22 Silver iodobromide emulsion (average particle size 0.27 μm, silver iodide content 2.0 mol%) 0.03 Sensitizing dye (SD-9) 4.2 × 10 ^-4 sensitizing dye (SD-10) 6.8 × 10 ^-5 yellow coupler (Y-1) 0.75 DIR compound (D-1) 0.010 High boiling point solvent (Oil-2) 0.30 Gelatin 1.20 12th layer: Medium sensitivity (2nd) blue-sensitive layer Silver iodobromide emulsion (average grain size 0.59 μm, silver iodide content 8.0 mol%) 0.30 sensitizing dye ( SD-9) 1.6 × 10 ^-4 sensitizing dye (SD-11) 7.2 × 10 ^-5 Yellow coupler (Y-1) 0.10 DIR compound (D-1) 0.010 High boiling solvent (Oil-2) 0.046 Gelatin 0.47 13 layers: high-sensitivity (third) blue-sensitive layer Silver iodobromide emulsion (average grain size 1.00 μm, silver iodide content 8.0 mol%) 0.85 sensitizing dye (SD-9) 7.3 × 10 ^-5 sensitizing dye (SD-11) 2.8 × 10 ^-5 Yellow coupler (Y-1) 0.11 High boiling solvent (Oil-2) 0.046 Gelatin 0.80 14th layer: 1st protective layer Silver iodobromide emulsion (average particle size 0.08 μm, iodine (Silver halide content: 1.0 mol%) 0.40 UV absorber (UV-1) 0.026 UV absorber (UV-2) 0.013 High boiling solvent (Oil-1) 0.07 High boiling solvent (Oil-3) 0.07 Formalin Scavenger (HS-1) 0.40 Gelatin 1.31 15th layer: 2nd protective layer Alkali-soluble matting agent (average particle size 2 μm) 0.15 Polymethyl methacrylate (average particle size 3 μm) 0.04 Slip agent (WAX-1) 0.04 Gelatin 0.55 Su− 1 0.02 Su-2 0.03 H-1 0.024 H-5 0.046 H-9 0.010

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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In the following examples, as an example of simultaneous multi-layer coating, 1
The case of 5 layers, 13 layers, and 11 layers will be described. As shown in Table 1, in the case of 13 layers, the 8th and 12th layers (blue,
Thirteen layers except for the green middle layer were used. In the case of 11 layers
The remaining 11 layers other than the 13 layers except for the fourth layer (red middle-sensitivity layer) and the fourteenth layer (two protective layers) were used.

However, in the case of 11 layers, the first protective layer contains the additive of the second protective layer.

With this configuration, multi-layer simultaneous coating was performed on a triacetyl cellulose film having a coating speed of 100 m / min and a thickness of 120 μm as a support. Y of each layer when wet coating, viscosity, and slide surface angle of each layer were set as shown in Table 1 and multi-layer simultaneous coating was performed.
The results of calculating the values are shown in FIG. 3, FIG. 4, and FIG.

From these graphs, in the comparative example under the conditions shown in Table 1, the Y value of a part of the interface exceeds 250, and the Y value of the sample of the present invention is lower than 250 at any interface. I understand.

Table 1 shows the results of actual coating surface conditions obtained by multi-layer simultaneous coating.

[0048]

[Table 1]

From the results shown in Table 1, it can be seen that the sample satisfying the condition Y ≦ 250 of the present invention shows a good coating state in any of the 11 layers, 13 layers, and 15 layers simultaneously.

[0050]

【The invention's effect】

According to the present invention, it is possible to simultaneously apply 11 or more layers of a coating liquid to obtain a uniform coating surface without color unevenness caused by ripples on a slide surface, and to provide a high productivity multilayer simultaneous coating method. Was completed.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a slide bead coating apparatus. FIG. 1B is an explanatory view of a coating liquid flowing state on a slide surface. FIG.

2A is a diagram showing a state of flow of a coating solution on a slide surface in the case of two-layer coating; FIG. 2B is a diagram showing a state of flow of a coating solution on a slide surface in a case of multilayer coating;

FIG. 3 is a graph showing the relationship between each interface and the Y value in the case of simultaneous application of 11 layers.

FIG. 4 is a graph showing the relationship between each interface and the Y value in the case of simultaneous application of 13 layers.

FIG. 5 is a graph showing the relationship between each interface and the Y value in the case of simultaneous application of 15 layers.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backup roll 2 Coating device 3 Decompression device 4 Slit 5 Slide surface 6 Lip 10 Web 12 Bead 13, 14 Coating solution A, B, C Coating layer θ Inclination angle L Flowing distance k Slit S Coating solution

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-108566 (JP, A) JP-A-1-131549 (JP, A) JP-A-2-245267 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) B05D 1/26 B05C 1/14 B05C 5/02 G03C 1/74

Claims (2)

(57) [Claims] 1. In a multi-layer simultaneous coating of 11 or more layers using a slide bead coating device or a curtain coating device having a slide surface on a continuously running support, the coating film is parallel to the slide surface of the falling liquid film on the slide surface. Wherein the shear rate d _u , d _{l above} and below the liquid-liquid interface and the flow down time t at the interface are (d _u + d _l ) / 2 × t ≦ 250. Coating method. 2. A multi-layer simultaneous coating method, wherein the coating liquid according to claim 1 is a coating liquid for a photosensitive material.