JP2002153797A - Extrusion die coater for simultaneous multi-layering and extrusion coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion die coater for a simultaneous multi-layering enabling the stable coating of film thickness distribution in the longitudinal and lateral directions and an extrusion coating method. SOLUTION: In the extrusion die coater for simultaneous multi-layering for simultaneously applying two or more coating layers to a continuously fed strip like support of which the coating position is held from a coating opposite surface by a back roll, the relation between the length Xn in the support feed derection of a lip along which a coating solution from the lowermost layer to the n-th layer flows and the distance hn between the lip along which the coating solution from the lowermost layer to the n-th layer flows and the support is 3hn<Xn<50 hn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion die coater and an extrusion die coater for simultaneous multilayer coating, in which two or more coating layers are simultaneously coated on a continuously transporting belt-like support whose coating position is maintained from the opposite side of the coating with a back roll. Related to the application method.

[0002]

2. Description of the Related Art In recent years, there have been many multilayer products in which each layer has an independent function for the purpose of imparting high performance to a coating film.
From the viewpoint of production efficiency, simultaneous multi-layer coating has become common. The slide coating method has been used since the oldest in simultaneous multi-layer coating.However, when a highly volatile solvent is used as the solvent for the coating liquid, the open part is large and the properties of the coating liquid change as the solvent evaporates. Have the problem of
On the other hand, a simultaneous multilayer extrusion die coater (hereinafter, also referred to as a die coater), in which the solvent is less volatilized in a closed system and a high accuracy of the film thickness distribution accuracy is obtained until just before the coating solution comes into contact with the support, is widely used. Used.

Generally, in coating using a die coater, in order to obtain a uniform coating film thickness, the flatness of the support is maintained, and the coater gap, which is the distance between the coating solution discharge position and the support, is stably maintained. For this reason, it is widely practiced to support a support at a coating position with a back roll. The outline of the extrusion coating method in which the support is supported by a back roll will be described with reference to the drawings.

[0004] FIG. 1 shows a state in which a backing roll holds the opposite side of the coating (hereinafter simply referred to as the back side) to a holding portion of a support.
It is a schematic diagram which shows application by the extrusion application method. In the figure, reference numeral 1 denotes a support that is continuously conveyed from the upstream to the downstream in the direction of the arrow (from bottom to top in the figure). 2 indicates a back roll and 3 indicates a die coater. The die coater refers to a coating machine that spreads the supplied coating liquid uniformly in the coating width direction and applies the coating liquid to the support. The configuration will be described with reference to a schematic diagram of the die coater 3 shown in FIG. In the present invention, the term “upstream side” refers to the side on which the support 1 is fed with respect to the die coater 3, and refers to the side opposite to the downstream side. The back surface is held by the back roll 2, and the coating liquid is extruded from the die coater 3 to the holding portion of the support 1 to be conveyed, and coating is performed.

FIG. 2 is a schematic diagram showing a cross section of the die coater 3. In the figure, 301a, 301b, 301c, 301q,
Reference numeral 301r denotes a bar constituting the die coater 3, which is fixed by bolts. 302a, 302b, 3
02c, 302q, and 302r indicate lips at the tip of each bar. Reference numerals 303a, 303b, and 303q denote slits formed between the bars. 304a, 304b, 3
Reference numerals 04c and 304q denote manifolds disposed on each bar and extending in the width direction of the die coater 3 for temporarily storing the supplied coating solution in order to uniformly supply the coating solution in the width direction. Although not shown in this drawing, each manifold has a coating liquid supply port for supplying a separate coating liquid, and the supplied coating liquid passes through the slits connected to the manifold and is placed on the support. The application is performed by being extruded. 305a indicates a coating liquid extruded from the slit 303a, 305b indicates a coating liquid extruded from the slit 303b, and 305q indicates a coating liquid extruded from the slit 303q.

A indicates a lowermost layer formed by the coating liquid 305a, B indicates a layer adjacent to the lowermost layer A formed by the coating liquid 305b, and Q indicates an uppermost layer formed by the coating liquid 305q.

Reference numeral 1 denotes a support which is continuously conveyed from upstream to downstream in the direction of the arrow (from bottom to top in the figure).

In a die coater, a manifold and a slit can be formed by increasing the number of bars according to the number of coating layers required. The coating width end of the die coater is sealed with various width regulating means, side plates and the like so that a desired coating width can be obtained.

With respect to the coating method shown in FIG. 1, a single-layer coating method disclosed in JP-A-56-95363 and JP-A-50-142463, and JP-A-45-1
Many patents have been filed with respect to coating methods and die coaters, such as those relating to the multi-layer coating method disclosed in Nos. 2390 and 46-236. These coating methods are methods of coating the support held by the back roll while keeping the coater gap usually at 1 mm or less.
The coater gap refers to the distance between the die coater lip and the support.

When a coating film is formed by simultaneous multi-layer coating on a support supported on a back roll using these die coaters, important factors for obtaining the stability of the coating film and the stable film thickness distribution are as follows. It is known that the coating liquid extruded from the slit has physical properties (particularly viscosity) and a coater gap, and a stable coating film cannot be obtained unless these are taken into consideration.

Factors affecting the coater gap include the mechanical accuracy of the die coater itself, the straightness in the coating width direction of the lip at the tip of the die coater, the cylindricity of the back roll, the rotational runout of the back roll, and the curvature of the back roll.

When the lip shown in FIG. 2 is simultaneously coated with a die coater on the same plane, the number of slits and lips for supplying a coating liquid increases in accordance with the layer to be coated. At this time, the coater gap of each lip differs at each position in the support transport direction depending on the curvature of the back roll, and the shift of the coater gap increases as the number of layers increases.

When the coater gap fluctuates in the longitudinal and lateral directions, the flow rate of the coating liquid varies, and the film thickness distribution in the longitudinal and lateral directions of the coating film fluctuates greatly. The disordered layers become uneven and streak-shaped on the coating film, and the thickness distribution fluctuates greatly.

When the viscosity of each layer is particularly different due to the physical properties of the liquid, the flow of each layer between the lip and the support is affected by the viscosity of each layer, and the flow rate of the coating liquid is fluctuated due to the fluctuation of the coater gap. As a result, the flow becomes more unstable and the coating film thickness becomes unstable.

In the extrusion coating method using a die coater, there has been a problem how to control the physical properties of the coating liquid of each layer and the coater gap to stabilize the coating film thickness. Improvements have been studied to solve these problems. For example, Japanese Patent Application Laid-Open No. 2000-153205 discloses a technique for improving the uniformity of a coating film by defining a lip length of an extrusion coater for single-layer coating. However, it is not a technique for solving the problem peculiar to the simultaneous multi-layer coating, but a further improvement of the coating film thickness stabilization is desired. The present inventors have conducted intensive studies on stabilization of the film thickness distribution in the longitudinal and lateral directions in the simultaneous multilayer coating method using a die coater, and as a result, have reached the present invention.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an extrusion die coater for simultaneous multi-layer and an extrusion coating method which enables stable coating with a film thickness distribution in the longitudinal and lateral directions.

[0017]

Means for Solving the Problems The present inventors have found that the above-mentioned object is achieved by the following constitutions.

1) In a simultaneous multi-layer extrusion die coater in which two or more coating layers are simultaneously coated on a belt-shaped support which is continuously conveyed while the coating position is maintained from the opposite side of the coating by a back roll, n layers from the lowest layer the length X _n of the support conveying direction of the coating liquid flows lip to the eye, relationship between the distance h _n between the lip through which the coating liquid from the bottom layer to the n-th layer support 3h _n <X _n < extrusion die coater for simultaneous multilayer characterized in that it is a 50h _n.

2) In a simultaneous multilayer extrusion die coater, in which two or more coating layers are simultaneously coated on a belt-like support that is continuously conveyed while the coating position is held from the opposite side of the coating by a back roll, immediately after the application of the lowermost layer When the coating thickness of W ₁ , the coating thickness immediately after the application of the n-th layer from the bottom layer is W _n, and the coater gap at the lip through which the coating liquid flows from the bottom layer to the n-th layer is h _n , 1 <h _n / h _n-1 <
_{(W n + W n-1} + ··· + W 1) / (W n-1 + W n-2 + ··
· + W ₁₎ and so as extrusion die coater for simultaneous multilayer, characterized in that the coater gap is expanded stepwise toward the support conveying direction downstream side.

3) In a simultaneous multilayer extrusion die coater in which two or more coating layers are simultaneously coated on a belt-like support that is continuously conveyed while the coating position is maintained from the opposite side of the coating by a back roll, the simultaneous multilayer extrusion Extrusion die coater for simultaneous multi-layer, characterized in that, of the bars forming the lug die die coater, only the bar at the most upstream side and the most downstream side in the support transport direction have a lip, and the other bars have no lip. .

4) In a simultaneous multi-layer extrusion die coater in which two or more coating layers are simultaneously coated on a belt-like support which is continuously conveyed while the coating position is held from the surface opposite to the coating by a back roll, all the lips are the same. On the plane, the total length from the most upstream position of the most upstream lip to the most downstream position of the most downstream lip in the support transport direction is Y, the diameter of the back roll is D, and the closest point between the back roll and the lip is simultaneous multilayer for extrusion die coater relationship of Y and D is represented by the following formula when the distance was h _{mi n.}

0.01 <D− (D^Two-Y^Two)^1/2/ H_min<0.1 5) The support of the lip through which the coating liquid flows from the lowermost layer to the nth layer
Length X in carrying direction _nAnd coating from the bottom layer to the nth layer
Distance h between the lip through which the cloth liquid flows and the support_nThe relationship is 3h_n
<X_n<50h_n2) or 4)
The extrusion die coater for simultaneous multi-layer as described.

6) In the extrusion coating method in which the coating position is held from the surface opposite to the coating by the back roll and two or more coating layers are simultaneously coated on the continuously transported belt-like support, the viscosity of the coating liquid in the lowermost layer is determined. An extrusion coating method, wherein μ1 is the smallest in the coating solution used, where μ1 is μ2 and the viscosity of the coating solution of the layer adjacent to the lowermost layer is μ2, and 1.5 <μ2 / μ1 <15.

(7) The extrusion coating method according to (6), wherein the extrusion die coater for simultaneous multilayer formation according to any one of (1) to (5) is used.

By these means, stable application of the film thickness distribution in the longitudinal and lateral directions by extrusion coating on the support held by the back roll becomes possible. This patent does not particularly limit the coating liquid to be applied as long as a plurality of coating films are simultaneously formed on a support supported on a back roll by a die coater. It is applied to the application of coating materials such as materials, ablation recording materials, magnetic recording media, and steel plate surface treatment. Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 is a schematic diagram showing the application state of the tip of the die coater at the time of simultaneous multilayer coating using a die coater in which each lip is on the same plane. Although not shown in the figure, the die coater is fixed, and the back roll 2 is
Are rotated in the same direction in accordance with the transfer speed of.

In the figure, h indicates a coater gap which is the distance between each lip and the support 1. ha indicates a coater gap which is the distance between the lip 302a and the support 1, hb indicates a coater gap which is the distance between the lip 302b and the support 1, and hc indicates a coater which is the distance between the lip 302c and the support 1. A gap is shown, and hr indicates a coater gap which is a distance between the lip 302r and the support 1. Each lip of the die coater 3 shown in the drawing is designed to be all on the same plane.

Wa indicates the coating thickness of the lowermost layer A immediately after coating formed by the coating liquid 305a, and Wb indicates the coating liquid 3
The coating thickness of the layer adjacent to the lowermost layer (hereinafter, also referred to as an adjacent layer) immediately after the coating formed by the coating liquid 05b indicates the coating thickness of the uppermost layer Q formed by the coating liquid 305q. Xa, Xb, Xc, Xq, and Xr indicate the lengths of the respective lips from the uppermost stream lip 302a to the lowermost stream lip 302r in the support conveying direction. Y indicates the total length of the lip from the most upstream position of the most upstream lip to the most downstream position of the most downstream lip in the support transport direction. That is, the length includes each lip length and each slit gap Za, Zb, Zq. The gap between the lip length Y and the support 1 is referred to as a coating liquid flow path. D indicates the diameter of the back roll. Other symbols are the same as those in FIG.

In the drawing, the most upstream lip of the die coater 3 refers to the lip 302a, and the most downstream lip refers to the lip 302r.

FIG. 4 is a schematic diagram showing the coating state of the tip of the die coater at the time of simultaneous multilayer coating using a die coater in which the coater gap between each lip and the support 1 becomes wider toward the downstream side. Although not shown in the figure, the die coater is fixed, and the back roll 2 rotates in the same direction in accordance with the transport speed of the support 1.

The coater gap between each lip and the support 1 is defined as hb <hc <... Based on the coater gap hb.
<Hr. Other symbols are the same as those in FIG.

FIG. 5 shows that, among the bars constituting the die coater, only the uppermost and lowermost bars have a lip, and the other bars use a die coater without a lip. It is a schematic diagram showing the application state of the tip.
In this figure, the most upstream bar 301a, the most downstream bar 301r
Are formed with lips 302a and 302r, respectively, but the other bars 301b, 301c and 301q are not formed with lips. Other symbols are the same as those in FIG.

As shown in FIG. 3, when all the lips are on the same plane, the coating liquids 305a, 305
b, 305q are extruded one after another and laminated to form each lip 3
Despite the increase in the flow rate between the substrates 02b, 302c, 302q, and 302r and the support, the amount of coating liquid flowing between each lip and the support is regulated by the support and each lip. On the other hand, since the coater gap becomes narrow, the flow of the coating liquid becomes unstable, and as a result, the coating film thickness becomes unstable, and particularly the wide film thickness distribution deteriorates.
Further, if the coater gap fluctuates in the width direction with respect to the back roll, the width of the film thickness is deteriorated because the flow path is constant. The problem with such a die coater is how to widen the coater gap without changing the coating film thickness.

The movement of the coating solution constituting each layer when applying using the die coater shown in FIG. 3 will be described. A coating liquid 305a forming the lowermost layer A extruded from the slit 303a flows between the lip 302b and the support, and a layer B adjacent to the lowermost layer A extruded from the slit 303b is formed between the lip 302c and the support. The coating liquid 305b and the coating liquid 305a flow and the lip 302
r and the support, the coating liquid 305q extruded from the slit 303q to form the uppermost layer Q and the lowermost layer A to the uppermost layer Q
The coating liquid that forms the layer below is flowing. At this time, each coating liquid forms a liquid-liquid interface and is applied to the support 1.

At this time, the coating liquids 305a and 305 sandwiched between the support 1 moving at a certain transport speed and each lip.
A shear stress in the direction of movement of the support acts on b and 305q, and the transport speed (coating speed) of the support 1 from the stopped state of the liquid.
Until it is rapidly accelerated and stretched. At this time, if the viscosity of the coating liquid is high with respect to the coating speed, the coating liquid cannot be stretched, and a state in which the coating liquid is torn off occurs. In order to cope with this problem, coating can be performed by lowering the coating speed or increasing the supply amount of the coating liquid and widening the coater gap h in accordance with the increase in the supply amount. I will. That is, high-speed stable film thickness application cannot be performed.

However, in the coating liquid forming the lowermost layer A to the uppermost layer Q, the viscosity of the coating liquid 305a forming the lowermost layer A is made lower than the viscosity of the other coating liquids 305b and 305q, and the coating film is formed. Each coating solution 305a, 30 to be formed
By reducing the viscosity of 5b, 305q from the uppermost layer side to the lowermost layer side, the shear stress of each coating solution is relaxed and the coating solution is not broken, so that no coating omission occurs and good. Application is possible.

Further, the viscosity of the low-viscosity coating solution 305a forming the lowermost layer A and the coating solution 30 forming the adjacent layer B
The larger the difference from the viscosity of the lower layer 5b, the greater the stretching of the low-viscosity coating solution 305a constituting the lowermost layer A, and the more the coating solution 305b constituting the adjacent layer B is not stretched. is there.

Since the coating liquid 305b constituting the adjacent layer B does not suddenly stretch, the average speed of the adjacent layer B alone decreases. If the supply amount of the coating liquid 305b constituting the adjacent layer B does not change, the thickness of the adjacent layer B increases instead of the average speed decreasing. As the thickness increases, the coater gap can be increased. If the coater gap can be enlarged, the influence of the deviation of the mechanical accuracy of the die coater itself on the film thickness distribution of the coating film becomes small, which is advantageous.

In the present invention, when performing simultaneous multilayer coating,
When the viscosity of the coating solution 305a of the lowermost layer A is μ1 and the viscosity of the coating solution 305b of the adjacent layer B is μ2, in order to stabilize the coating film thickness, μ1 is the value of each coating solution used for simultaneous multilayer coating. And the ratio of μ1 to μ2 is 1.5 <μ2 /
μ1 <15, more preferably 2.0 <μ2 / μ1
<10. In the case of 1.5 or less, the enlargement of the coater gap is small and a large effect cannot be obtained. If it is 15 or more, the liquid-liquid interface is disturbed and the coating film thickness becomes unstable, which is not preferable.

In the case of the die coater shown in FIG. 3, the curvature of the back roll 2, the total lip length Y and each coater gap (h
The relationship of b, hc, hr) also affects the coating film thickness. That is, each lip (302a, 302b, 302c, 302)
As for the distance between r) and the back roll 2, the coater gap differs at each position of the lip due to the relationship between the total length Y of the lip including the slit gap and the curvature of the back roll. In particular, when the number of coating films to be formed is large and the total lip length is necessarily long, the shift of the coater gap becomes large. The problem is that the total length of the lip is Y, the diameter of the back roll is D, and the closest coater gap between the back roll 2 and each lip is h.
_This can be solved by expressing the relationship between Y and D when _min is represented by the following equation.

0.01 <D− (D ² −Y ² ) ^1/2 / h _min <0.1 More preferably, 0.06 <D− (D ² −Y ² ) ^1/2 / h
_min <0.1. If it is less than 0.01, the die coater becomes large and handling becomes difficult.
In the case of 1 or more, the flow of the coating liquid under the lip follows compression and expansion according to the curvature of the back roll, and the coating film becomes unstable, which is not preferable.

When simultaneously coating two or more layers with an extrusion die coater, as shown in FIG. 4, the coat gap is increased as each liquid is laminated between the lip and the support in the direction of transport of the support. Is preferably enlarged. That is, when the lip shown in FIG. 3 is on the same plane, the flow of the coating liquid in question is the flow of the coating liquid pushed out from each slit because the coater gap is widened in the downstream direction. As a result, the film thickness distribution becomes stable. Further, when the coater gap is widened, the influence of the coater gap fluctuation on the coating solution is reduced, and the influence on the coating film thickness fluctuation is reduced.

In the case of a die coater in which the coater gap is widened toward the downstream side as shown in FIG. 4, it is necessary to perform coating in the range of the following conditional expression in order to stabilize the coating film thickness. That is, the enlargement of the coater gap in the direction of transport of the support is related to the flow rate between the target lip and the support, the coating thickness immediately after the application of the lowermost layer is W ₁ , and the coating thickness immediately after the application of the nth layer from the lowermost layer. the coating thickness and W _n, when the coater gap in the lip through which the coating liquid from the bottom layer to the n-th layer and the _{h n, 1 <h n /} h n-1 <(W n + W n-1 + ... +
(W ₁ ) / (W _n−1 + W _n−2 +... + W ₁ ). If h _n / h _n-1 is larger than this range, the coating film thickness becomes rather unstable.

For the stability of the coating film, it is important to stabilize the flow of the liquid between the lip and the support. In particular, in the case of multi-layer coating, if the next layer is laminated while the liquid-liquid interface laminated between the lip and the support is not stable, the disturbance of the boundary of each layer continues, and the coating film becomes unstable. In order to stabilize the coating film between the lip and the support, the length of the n-th lip in the support conveying direction through which the coating liquid forming the n-th layer flows from the lowermost layer is X _n , and the n-th layer is the n-th layer from the lowermost layer. X _n and h _n , _where h _n is the coater gap of the n-th lip through which the coating solution forming
The relationship is _{3h n <X n <50h n} , more preferably _{5h n <X n <30h n} . The length X _n of the lip 3h _n
In the following cases, the coating liquid extruded from the slit is disturbed at a place where it merges with another coating liquid, and the coating film thickness becomes unstable, which is not preferable. If the length X _n of the lip over 50h _n, die coater increases and the handling unfavorably difficult. The above relational expression is applied to the die coater shown in FIGS.

As another method for stabilizing the liquid-liquid interface,
It is also possible to use a die coater having no lip according to the present invention, whereby the coating film can be stabilized. This can be achieved by, among the bars forming the die coater shown in FIG. 5, only the bars at the most upstream side and the most downstream side in the support conveying direction have lips, and the other blocks do not have lips. That is, these blocks define the liquid-liquid interface not by a plane but by a line. The coating liquid laminated on the line of the bar does not have a distance where the flow is stable, but the position of the liquid-liquid interface is forcibly defined, so that no large disturbance occurs. Further, since the block on the most downstream side in the support conveying direction has a lip, the block has a distance for stabilizing the flow of the coating liquid in a state where all the layers are finally laminated. The block on the uppermost stream side in the support conveying direction can be coated without a lip, but the lip provides higher coating stability when the coater gap fluctuates.

[0046]

The present invention will be described below with reference to examples of the present invention.
The present invention is not limited to these examples.

Example 1 <Preparation of coating liquid> Polyvinyl butyral was dissolved in methyl ethyl ketone, and coating liquids having different viscosities as shown in Table 1 were prepared by changing the solid content concentration. The viscosity of the coating solution is a value measured at 25 ° C. with a B-type viscometer.

[0048]

[Table 1]

From the coating solutions shown in Table 1, No. 5,4,
3 was adjusted by using a die coater having three layers of the die coater shown in FIG. 3 so as to adjust the coating liquid supply flow rate to the slits so that the target coating film thickness immediately after application of each layer was as shown in Table 2, and 100 μm PET supported by a back roll. Using a die coater having a different lip length as shown in Table 3, the coater gap was set as shown in Table 3, and the sample was coated and dried to produce the samples shown in Table 3.

The back roll has a diameter of 200 mm and a surface length of 13
The coating width was 1000 mm with a metal roll having a chrome-plated surface treatment of 00 mm, and the coating was performed 100 m at a coating speed of 30 m / min. The target coating film thickness is a coating film thickness immediately after coating calculated from a coating speed for coating a unit area and a coating liquid supply flow rate required for coating the unit area.

[0051]

[Table 2]

[0052]

[Table 3]

Table 4 shows the measurement results of the width and length film thickness distributions of these samples. The coating film thickness of the sample obtained after coating and drying was measured at 5 cm at intervals of 2 cm using a contact-type film thickness meter (Electronic micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.).
The values measured at the zero point are e _i = e ₁ to e ₅₀ , and the average value is E
= Σe _i / 50, the maximum value among the e _i and rated e _max, the minimum value as the film thickness distribution in the width hand the variation range of the following formula is taken as e _min. The longitudinal film thickness distribution is
The average value of 0 points is taken as one value, and 2
The values measured at the 0 point are f _j = f _{1 to} f ₂₀ , and the average value is F
= Σf _j / 50, the maximum value is f _max , and the minimum value is f
_The variation width represented by the following equation when the value was _min was evaluated as a longitudinal film thickness distribution.

Wide film thickness distribution (% / m) = (e _max -e
_min ) / E × 100 Longitudinal film thickness distribution (% / 100 m) = (f _max −f _min ) /
F × 100

[0055]

[Table 4]

[0056] Samples 1-1 3h _n <X _n <film thickness distribution in the width hand at 50h _n is good, 1-2 film thickness distribution in the width hand at 5h _n <X _n <30h _n is even better, 1 -3 thickness distribution in the width hand in X _n <3h _n worsened.

Example 2 Using the coating liquid prepared in Example 1, the flow rate of the coating liquid supplied to the slit was adjusted so that the target coating film thickness immediately after coating each layer was as shown in Table 5, and the results are shown in FIG. Using a die coater having three layers of die coaters, the lip length and coater gap of each die coater are set as shown in Table 6, and coated and dried on a 100 μm PET support supported by a back roll.
The samples shown in Table 1 were prepared. The back roll, coating width, coating speed and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results were shown in Table 6.
Shown in

[0058]

[Table 5]

[0059]

[Table 6]

[0060] Although Sample 2-1 film thickness distribution in the range of 3h _n <X _n <50h _n is relatively good, the sample 2-2 X
film thickness distribution in the width hand for the _n> 50h _n is deteriorating.

Example 3 The target coating film thickness immediately after application of each layer by a die coater for simultaneous application of three layers of the coating solution prepared in Example 1 was determined as shown in Table 2 of Example 1.
The coating liquid supply flow rate to the slit was adjusted so that the coating was performed, and the sample was coated and dried on a 100 μm PET support supported by a back roll using a die coater having a different coater gap shown in Table 7 to produce a sample shown in Table 7. did.

The back roll, coating width, coating speed and coating length were the same as in Example 1. The width and length film thickness distributions of the obtained sample were measured by the same method as in Example 1, and the results are shown in Table 8.

[0063]

[Table 7]

[0064]

[Table 8]

Sample No. The die coater used in 3-1 is a die coater using three layers of the die coater shown in FIG. The die coater used in 3-2 and 3-3 is a die coater in which the die coater shown in FIG. 4 is used for three layers. 3 and 4, the coater gap hb is represented by h1 in the table,
hc corresponds to h2 and hr corresponds to h3.

The lip length of each die coater used was 1 mm, and the slit gap was 250 μm.

As shown in the above table, the coater gap ratio, the thickness of the coating film immediately after coating each layer, the ratio of the viscosity of the coating solution of the lowermost layer to the viscosity of the coating solution of the layer adjacent to the lowermost layer, and the length of the lip in the transport direction of the support. It was confirmed that the film thickness was stable when the relationship between the support and the distance between the support and the lip through which the coating liquid for forming the uppermost layer flowed was within the range of the present invention.

Example 4 Using the coating solution prepared in Example 1, the supply flow rate of the coating solution to the slit was adjusted so that the target coating thickness immediately after coating each layer was as shown in Table 2 of Example 1. Using the die coater shown in FIG. 3 and the die coater shown in FIG. 5, a sample shown in Table 9 was prepared by coating and drying on a 100 μm PET support supported by a back roll.

The back roll, coating width, coating speed and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 9.

The die coater used had a lip length of 1 m.
3 and FIG. 5 having a slit gap of 250 μm. Coater gap is 130 in each case
μm.

[0071]

[Table 9]

Sample No. The die coater used in 4-1 is a die coater using three layers of the die coater shown in FIG. The die coater used in 4-2 is a die coater in which the die coater shown in FIG. 3 is used for three layers. In the die coater of FIG. 5, a wider film thickness distribution was better than in the die coater of FIG.

Example 5 Using the coating solution prepared in Example 1, the flow rate of the coating solution supplied to the slit was adjusted so that the target coating thickness immediately after the application of each layer was as shown in Table 2 of Example 1. The die coater shown in 3
Using the die coater for the layer, a sample shown in Table 10 was prepared by coating and drying on a 100 μm PET support supported by a back roll having a different diameter as shown in Table 10.

The coating width, coating speed and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 10.

The die coater used had a lip length of 0.8 mm, a slit gap of 250 μm, and a total lip length of Y.
Was 3.95 mm. By using back rolls having different diameters, the coating solution in the middle layer was set so as to face the axial direction of the back roll to prepare a coated sample. At this time, the minimum coater gap h _min was 130 μm.

The value B in the table means the calculation result of the following equation. D− (D ² −Y ² ) ^1/2 / h _min

[0077]

[Table 10]

Sample 5-1 in which the value B is less than 0.1 has a wide film thickness distribution, and Sample 5 in which the value B is larger than 0.1.
In the case of 2,5-3, the film thickness distribution of the width is deteriorated.

Example 6 The target coating film thickness immediately after the application of each layer by a die coater for simultaneously coating the three layers of the coating solution prepared in Example 1 was determined as shown in Table 2 of Example 1.
The coating liquid supply flow rate to the slit was adjusted so as to obtain a 100 μm PET support supported by a back roll using a die coater with a different coater gap shown in Table 11 and dried to produce a sample shown in Table 11. did.

The back roll, coating width, coating speed, and coating length were the same as in Example 1. The film thickness distribution in the width and length directions of the obtained sample was measured by the same method as in Example 1, and the results are shown in Table 12.

[0081]

[Table 11]

[0082]

[Table 12]

Sample No. The die coater used in 6-1 is a die coater in which the die coater shown in FIG. The die coater used in 6-2 and 6-3 is a die coater in which the die coater shown in FIG. 4 is used for three layers. 3 and 4, the coater gap hb is represented by h1 in the table,
hc corresponds to h2 and hr corresponds to h3.

The lip lengths of the die coaters used were all 1 mm, and the slit gap was 250 μm.

As shown in the above table, 3h _n
<And X _n <50h _n, coater gap ratio and the layers immediately after application of the coating thickness, the ratio of the viscosity of the coating solution for the lowermost layer of the coating liquid viscosity and the layer adjacent to the bottom layer, and the length of the support conveying direction of the lip It was confirmed that the film thickness was stable if the relationship between the distance between the lip through which the coating liquid for forming the uppermost layer flows and the support was within the range of the present invention.

Example 7 Using the coating solution prepared in Example 1, the flow rate of the coating solution supplied to the slit was adjusted so that the target coating film thickness immediately after the application of each layer was as shown in Table 2 of Example 1. The die coater shown in 3
Using the die coater for the layer, the lip length and the coater gap were changed as shown in Table 13 and applied and dried on a 100 μm PET support supported by a back roll to produce the samples shown in Table 13.

The back roll, the coating width, the coating speed and the coating length were the same as in Example 1, and the slit gap was 250 μm.
And The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 13.

The value B in the table means the calculation result of the following equation. D− (D ² −Y ² ) ^1/2 / h _min

[0089]

[Table 13]

The sample 7-1 has 3h _n <X _n <50h _n but the B value exceeds 0.1, so that the film thickness distribution in the wide side is 3h _n.
n <X _n <50h _n and B value falls below 0.1 Sample 7
2 is better. Samples 7-3 are beyond the X _n <3h _n and B value of 0.1, the film thickness distribution in the width hand worsened.

Example 8 Using a die coater having three layers of the die coater shown in FIG. 3, various coating solutions prepared in Example 1 were combined as shown in Table 14 to prepare samples. Table 14 shows the results obtained by measuring the film thickness distribution by the method. Note that the slit gap was 250 μm. The target film thickness immediately after the application of each layer is 30 μm for the uppermost layer, 40 μm for the adjacent layer, and 30 μm for the lowermost layer.
And The back roll, coating width, coating speed and coating length were the same as in Example 1.

[0092]

[Table 14]

The viscosity of the coating solution used for the lowermost layer was μ
1. When the viscosity of the coating solution used for the adjacent layer is μ2,
In Sample 8-1, μ1 was the smallest in all layers, and 1.5 <μ2 / μ1. The film thickness distribution in the width was good. In Sample 8-2, μ1 was the smallest in all layers, and 1.5 <μ2 / μ1. The thickness distribution of the hand is shown in Sample 8-1.
Even better, sample 8-3 has the smallest μ1 in all layers,
When 2 / μ1 <1.5, the film thickness distribution of the width is deteriorated. Sample 8-4
Is 1.5 <μ2 / μ1, but μ1 is not minimum in all the layers, so that the film thickness distribution of the width is poor. In sample 8-5, μ1 was not the smallest in all layers, and 1.5 <μ2 / μ1 <15
As a result, the width of the film thickness distribution was greatly deteriorated. In Sample 8-6, μ1 was the smallest in all layers, and μ2 / μ1 <15, so that the film thickness distribution was wider. In Sample 8-7, μ1 was the smallest in all layers, but μ2 /
μ1> 15, resulting in a poor film thickness distribution.

Example 9 Using the coating solution prepared in Example 1, the flow rate of the coating solution supplied to the slit was adjusted so that the target coating film thickness immediately after application of each layer was as shown in Table 15, and the sample of Example 1 was used. The lip length and coater gap of the die coater used in 1-1 were changed as shown in Table 16, and 100 μm supported by the back roll.
A sample shown in Table 16 was prepared by coating and drying on an mPET support.

The back roll, coating width, coating speed and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 16.

[0096]

[Table 15]

[0097]

[Table 16]

[0098] Samples 9-1 1.5 <μ2 / μ1 <15 and 3h _n <X _n <film thickness distribution in the width hand at 50h _n is good, 9-
2 1.5 <μ2 / μ1 <15 and 5h _n <X _n <30h
_{In n} , the film thickness distribution is wider, and in 9-3, 1.5 <μ
2 / μ1 <15, but when X _n <3h _n , the film thickness distribution over a wide area deteriorated.

Example 10 The target coating film thickness immediately after application of each layer by a die coater for simultaneously coating three layers of the coating solution prepared in Example 1 was as shown in Table 1 of Example 9.
5. Adjust the flow rate of the coating solution supplied to the slit so that it becomes 5.
Using a die coater having a different coater gap shown in Table 17 on a 100 μm PET support supported by a back roll and drying, a sample shown in Table 17 was produced.

The back roll, coating width, coating speed and coating length were the same as in Example 1. The width and length film thickness distributions of the obtained sample were measured in the same manner as in Example 1, and the results are shown in Table 18.

[0101]

[Table 17]

[0102]

[Table 18]

Sample No. The die coater used in No. 10-1 is a die coater in which the die coater shown in FIG. The die coater used in 10-2 and 10-3 is a die coater using three layers of the die coater shown in FIG. 3 and 4, the coater gap hb is h1 in the tables.
, Hc corresponds to h2, and hr corresponds to h3.

The lip lengths of the die coaters used were all 1 mm, and the slit gap was 250 μm.

As shown in the above table, 1.5 <μ2 / μ1 <1
5 and the coater gap ratio and the coating thickness immediately after the application of each layer,
The present invention relates to the ratio of the viscosity of the coating solution of the lowermost layer to the viscosity of the coating solution of the layer adjacent to the lowermost layer, the relationship between the length of the lip in the carrier transport direction and the distance between the lip through which the coating solution forming the uppermost layer flows and the support. It was confirmed that the film thickness was stable within the range.

Example 11 Using the coating solution prepared in Example 1, the flow rate of the coating solution supplied to the slit was adjusted so that the target coating film thickness immediately after the application of each layer was as shown in Table 15 in Example 9. Using the die coater shown in FIG. 3 and the die coater shown in FIG. 5, a sample shown in Table 19 was prepared by coating and drying on a 100 μm PET support supported by a back roll.

The back roll, coating width, coating speed, and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 19.

The die coater used had a lip length of 1 m.
m, the die coater of FIG. 3 having a slit gap of 250 μm;
The die coater of FIG. 5 was used. The coater gap was 130 μm in each case.

[0109]

[Table 19]

Sample No. The die coater used in No. 11-1 is a die coater using three layers of the die coater shown in FIG. The die coater used in 11-2 is a die coater using three layers of the die coater shown in FIG. The viscosity ratio of the coating solution used for the lowermost layer and the adjacent layer is 1.5 <μ2
In the range of / μ1 <15, the die coater of FIG. 5 has a wider film thickness distribution than the die coater of FIG.

Example 12 Using the coating solution prepared in Example 1, the supply flow rate of the coating solution to the slit was adjusted so that the target coating film thickness immediately after the application of each layer was as shown in Table 15 in Example 9. Using a die coater having three layers of the die coater shown in FIG. 3 and supported by back rolls having different back roll diameters shown in Table 20
A sample shown in Table 20 was prepared by coating and drying on a 0 μm PET support.

The coating width, coating speed and coating length were the same as in Example 1. The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 20.

The die coater used had a lip length of 0.8 mm, a slit gap of 250 μm, and a total lip length of Y.
Was 3.95 mm. By using back rolls having different diameters, the coating solution in the middle layer was set so as to face the axial direction of the back roll to prepare a coated sample. At this time, the minimum coater gap h _min was 130 μm.

The value B in the table means the calculation result of the following equation. D− (D ² −Y ² ) ^1/2 / h _min

[0115]

[Table 20]

Sample 12-1 in which 1.5 <μ2 / μ1 <15 and the value B is less than 0.1 has a good wide film thickness distribution, and 1.5 <μ2 / μ1 <15. , The value B is 0.1
In the larger samples 12-2 and 12-3, the wider film thickness distribution deteriorates.

Example 13 The target coating film thickness immediately after application of each layer by a die coater for simultaneous application of three layers of the coating solution prepared in Example 1 was as shown in Table 1 of Example 9.
5. Adjust the flow rate of the coating solution supplied to the slit so that it becomes 5.
Using a die coater having a different coater gap shown in Table 21 on a 100 μm PET support supported by a back roll, the sample was coated and dried to produce a sample shown in Table 21.

The back roll, coating width, coating speed and coating length were the same as in Example 1. The width and length film thickness distributions of the obtained sample were measured by the same method as in Example 1, and the results are shown in Table 22.

[0119]

[Table 21]

[0120]

[Table 22]

Sample No. The die coater used in No. 13-1 is a die coater in which the die coater shown in FIG. The die coater used in 13-2 and 13-3 is a die coater in which the die coater shown in FIG. 4 is used for three layers. 3 and 4, the coater gap hb is h1 in the tables.
, Hc corresponds to h2, and hr corresponds to h3.

The lip length of each die coater used was 1 mm, and the slit gap was 250 μm.

As shown in the above table, as shown in sample 13-3, 1.
5 <μ2 / μ1 <15 and, and _{3h n <X n <50h n} , coater gap ratio and the layers immediately after application of the coating thickness, the coating liquid viscosity of the lowermost coating solution viscosity and the layer adjacent to the lowermost layer It was confirmed that the film thickness was stable if the relationship between the ratio, the length of the lip in the support conveying direction, and the distance between the lip through which the coating liquid for forming the uppermost layer flows and the support was within the range of the present invention.

Example 14 Using the coating solution prepared in Example 1, the flow rate of the coating solution supplied to the slit was adjusted so that the target coating thickness immediately after the application of each layer was as shown in Table 15 of Example 9, and Using a die coater in which the die coater shown in FIG. 3 was used for three layers, each lip length and coater gap were changed as shown in Table 23, coated and dried on a 100 μm PET support supported by a back roll, and shown in Table 23. A sample was prepared.

The back roll, the coating width, the coating speed and the coating length were the same as in Example 1, and the slit gap was all 250 μm.
And The film thickness distribution of the obtained sample was measured in the same manner as in Example 1, and the results are shown in Table 23.

The value B in the table means the calculation result of the following equation. D− (D ² −Y ² ) ^1/2 / h _min

[0127]

[Table 23]

The sample 14-1 had 1.5 <μ2 / μ1 <15
And, 3h _n <X _n <because there the 50h _n is the B value exceeds 0.1, the film thickness distribution in the width hand 1.5 <μ2 / μ1 <1
5 _{and, 3h n <X n <50h} n and B value is better samples 14-2 drops below 0.1. Although Sample 14-3 is 1.5 <μ2 / μ1 <15, X n <3h n and B
The value exceeded 0.1, and the film thickness distribution in the width was deteriorated.

[0129]

According to the present invention, stable simultaneous application of the film thickness distribution in the longitudinal and lateral directions can be performed in simultaneous multilayer coating using a die coater.

[Brief description of the drawings]

FIG. 1 is a schematic view showing application by an extrusion application method to a holding portion of a support on which a surface opposite to an application is held by a back roll.

FIG. 2 is a schematic diagram showing a cross section of a die coater.

FIG. 3 is a schematic diagram illustrating a coating state of a tip portion of a die coater at the time of simultaneous multilayer coating using a die coater in which each lip is on the same plane.

FIG. 4 is a schematic view showing a coating state of a tip portion of a die coater at the time of simultaneous multilayer coating using a die coater in which a coater gap between each lip and a support becomes wider toward a downstream side.

FIG. 5 shows a top of the die coater at the time of simultaneous multi-layer coating, in which only bars on the most upstream side and the most downstream side among the bars constituting the die coater have a lip, and the other bars use a die coater without a lip. FIG. 3 is a schematic view illustrating a state of application of the present invention.

[Explanation of symbols]

1 Support 2 Back Roll 3 Die Coater 301a, 301b, 301c, 301q, 301r
Bars 302a, 302b, 302c, 302q, 302r
Lips 303a, 303b, 303q Slits 304a, 304b, 304c, 304q Manifolds 305a, 305b, 305q Coating solution A Lowermost layer B Layer adjacent to lowermost layer Q Topmost layer h, ha, hb, hc, hr Coater gap Wa, Wb, Wr coating film thickness Xa, Xb, Xc, Xq, Xr Length of lip in the direction of conveyance of support Y Total lip length Za, Zb, Zq Slit gap D Diameter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B05D 3/00 B05D 3/00 D G11B 5/84 G11B 5/84 Z

Claims (7)

[Claims] 1. A simultaneous multilayer extrusion die coater in which two or more coating layers are simultaneously coated on a belt-shaped support which is continuously conveyed while a coating position is held from a surface opposite to the coating by a back roll. the length X _n of the support conveying direction of the coating liquid flows lip to the eye, relationship between the distance h _n between the lip through which the coating liquid from the bottom layer to the n-th layer support 3h _n <X _n < extrusion die coater for simultaneous multilayer characterized in that it is a 50h _n. 2. A simultaneous multi-layer extrusion die coater in which two or more coating layers are simultaneously coated on a continuously conveyed belt-like support while the coating position is maintained from the opposite side of the coating by a back roll, immediately after the application of the lowermost layer. The film thickness of W ₁ , the film thickness immediately after the application of the n-th layer from the bottom layer is W _n ,
When the coater gap in the lip through which the coating liquid from the bottom layer to the n-th layer and the _{h n, 1 <h n /} h n-1 <(W n +
_{W n- 1 + ··· + W 1} ) / (W n-1 + W n-2 + ··· +
W ₁₎ and so as extrusion die coater for simultaneous multilayer, characterized in that the coater gap is expanded stepwise toward the support conveying direction downstream side. 3. A simultaneous multilayer extrusion die coater for simultaneously coating two or more coating layers on a continuously transported belt-like support, wherein a coating position is held from a surface opposite to the coating by a back roll. Extrusion die coater for simultaneous multi-layer, characterized in that, of the bars forming the lug die coater, only the bar at the most upstream side and the most downstream side in the support conveying direction have a lip, and the other bars have no lip. . 4. A simultaneous multilayer extrusion die coater in which two or more coating layers are simultaneously coated on a belt-shaped support which is continuously conveyed while a coating position is held from a surface opposite to the coating by a back roll, all the lips are the same. On the plane, the total length from the most upstream position of the most upstream lip to the most downstream position of the most downstream lip in the support transport direction is Y, the diameter of the back roll is D, and the closest point between the back roll and the lip is A simultaneous multilayer extrusion die coater in which the relationship between Y and D when the distance is h _min is represented by the following equation. ^{0.01 <D- (D 2 -Y 2} ) 1/2 / h min <0.1 5. The length _{Xn of the} lip through which the coating liquid flows from the lowermost layer to the nth layer in the support transport direction, and the distance h between the lip through which the coating liquid flows from the lowermost layer to the nth layer and the support. simultaneous multilayer for extrusion die coater according to claim 2 or 4, wherein the relationship of _n is _{3h n <X n <50h n} . 6. An extrusion coating method in which a coating position is held from a surface opposite to a coating by a back roll and two or more coating layers are simultaneously coated on a continuously transported belt-like support. An extrusion coating method, wherein μ1 is the smallest in the coating solution used, where μ1 is μ2 and the viscosity of the coating solution of the layer adjacent to the lowermost layer is μ2, and 1.5 <μ2 / μ1 <15. 7. The extrusion coating method according to claim 6, wherein the extrusion die coater according to any one of claims 1 to 5 is used.