JPWO2020039990A1 - Method of manufacturing a laminate - Google Patents

Abstract

It has at least a step of simultaneously applying a plurality of coating liquids including the first coating liquid and the second coating liquid on the base material to be continuously conveyed by using a slot die, and the first coating liquid is placed on the base material. It is a coating liquid that is applied in contact, the second coating liquid is a coating liquid that is applied adjacent to the first coating liquid, and the solid content content A of the first coating liquid and the solid of the second coating liquid. The ratio A / B to the component content B is 0.1 or less, the shortest distance d1 between the lip surface on the downstream side in the substrate transport direction and the substrate in the slot for applying the second coating liquid, and the substrate transport. The difference (d1-d2) between the shortest distance d2 between the upstream lip surface and the base material in the direction is 10 μm or more, and the relationship between the shortest distance d2 and the thickness h of the coating film formed from the first coating liquid is A method for producing a laminated body, which satisfies d2> 3 × h.

Description

The present disclosure relates to a method for producing a laminate.

By a continuous process using a roll-to-roll method, a coating liquid containing solid content is applied onto a substrate that is continuously conveyed using a slot die, and a target thin coating layer (for example, a coating with a dry film thickness of 5 μm or less) is applied. A method of forming a work layer) to manufacture a laminated body is known.

As an example of a method for producing a laminate, Japanese Patent Application Laid-Open No. 2002-059062 describes coating of two or more layers on a strip-shaped support in which the opposite surface to be coated is held by a back roll and continuously transported from upstream to downstream. In an extrusion coating method for simultaneously coating layers, an extrusion coating method is disclosed, characterized in that the viscosity of the lowest layer is lower than that of adjacent layers.

Further, in Japanese Patent Application Laid-Open No. 2013-220385, a backup roll that supports a web to be transported and a lip surface that is arranged to face the backup roll and discharges coating liquid from the tips of a plurality of slots, respectively, and is a die tip surface. A slot die that simultaneously coats multiple coating liquids on the web transported by forming a coating liquid bead in the clearance between the web, and a decompression device that reduces the pressure on the upstream side of the coating liquid bead in the web transport direction. Of the lip surfaces on both sides of the plurality of slots, the end of the lip surface on the downstream side when viewed from the web transport direction of the lip surface where the interfaces of the plurality of coating liquids come into contact with each other is formed into a curved shape having a convex cross section. A coating apparatus characterized by the above, and a method for producing a film with a coating film using the coating apparatus are disclosed.

Further, Japanese Patent Application Laid-Open No. 2013-052329 describes a multilayer film for producing a film with a multilayer film by simultaneously coating a coating liquid having a viscosity of 40 mPa · s or less on the surface of a web that is supported by a backup roll and runs continuously. A method for manufacturing a film with a film, which is a preparatory step of preparing a die composed of a plurality of blocks and a suction device for sucking air, and a suction device from the upstream side of the die in the traveling direction of the web. A decompression step of depressurizing the space between the die tip and the web by sucking air, and a coating liquid being discharged from the die tip to the web while depressurizing in the depressurization step to form a multilayer film on the web. The die has a pocket for storing the coating liquid formed by combining a plurality of blocks, and the pocket is such that the coating liquid supplied from the pocket is discharged to the web. , The downstream lip, which is located below the coating point, which is the position in contact with the web or the coating film formed on the web, and is the tip surface of the most downstream block in the traveling direction, and the web. The shortest distance between and is d1, and the shortest distance between the adjacent lip and the web, which is the tip surface of the block on the upstream side of one of the most downstream blocks and is located next to the downstream lip, is d2. When the width in the traveling direction is L2, the film thickness of the uppermost layer is h1, and the total film thickness of all the films except the uppermost layer is h2, the blocks are installed so as to satisfy all of the formulas 1 to 4. A method for producing a film with a multilayer film in which a die is formed is disclosed.
10 μm ≦ (d1-d2) ≦ 200 μm Equation 1
d2 ≤ 3 × h2 Equation 2
50 μm ≤ L2 ≤ 200 μm Equation 3
dP / dX> 0 Equation 4

When a laminate having a thin coating layer (hereinafter, also referred to as "thin layer") is produced on a base material using a slot die, for example, step unevenness due to a change in the distance between the die and the base material occurs. In addition, coating streaks may occur due to the movement of the meniscus (that is, the curved surface at the gas-liquid interface) of the coating liquid formed on the upstream side of the die in the substrate transport direction.
Here, "step unevenness" means that the band-shaped film thickness unevenness extending in the width direction of the base material (that is, the direction perpendicular to the transport direction of the base material) repeats the magnitude of the film thickness in the transport direction of the base material. It appears, and the repetition interval of the thickness is equal or random.
Further, the "coating streak" means that linear film thickness unevenness extending in the transport direction of the base material appears alone or in a plurality of lines, and is an interval between the film thickness unevenness and the adjacent film thickness unevenness when three or more of them appear. May be evenly spaced or random.
The uneven film thickness may be visually recognized as shading or repeating shading when the laminated body is placed on a light table and the laminated body is irradiated with transmitted light for observation. Further, the film thickness unevenness may be detected by measuring the film thickness of the laminated body with, for example, a contact type continuous film thickness measuring device.

An object to be solved by one embodiment of the present invention is to provide a method for producing a laminated body capable of forming a coating layer on a substrate in which the occurrence of coating streaks and step unevenness is suppressed.

Specific means for solving the problem include the following aspects.

<1> At least a step of simultaneously applying a plurality of coating liquids including a first coating liquid and a second coating liquid on a substrate that is continuously conveyed using a slot die is provided.
The first coating liquid is a coating liquid that is applied in contact with the base material.
The second coating liquid is a coating liquid that is applied adjacent to the first coating liquid.
The ratio A / B of the solid content content A of the first coating liquid to the solid content content B of the second coating liquid is 0.1 or less.
Difference between the shortest distance d1 between the downstream lip surface in the base material transport direction and the base material and the shortest distance d2 between the upstream lip surface in the base material transport direction and the base material in the slot for applying the second coating liquid. (D1-d2) is 10 μm or more,
A method for producing a laminate, wherein the relationship between the shortest distance d2 and the thickness h of the coating film formed from the first coating liquid satisfies d2> 3 × h.

<2> The method for producing a laminate according to <1>, wherein the first coating liquid is a coating liquid having a viscosity of 2 mPa · s or less.
<3> The method for producing a laminate according to <1> or <2>, wherein the first coating liquid is a coating liquid having a viscosity of 1 mPa · s or more.

<4> The method for producing a laminate according to any one of <1> to <3>, wherein the first coating liquid is a coating liquid containing 90% by mass or more of a solvent with respect to the mass of the first coating liquid.
<5> The method for producing a laminate according to <4>, wherein the solvent is a single organic solvent.
<6> The method for producing a laminate according to any one of <1> to <5>, wherein at least a part of the solvent contained in the first coating liquid is the same as the solvent contained in the second coating liquid.

According to one embodiment of the present invention, there is provided a method for producing a laminate capable of forming a coating layer in which the occurrence of coating streaks and step unevenness is suppressed on a base material.

It is schematic cross-sectional view which shows an example of the coating apparatus applied to a multi-layer coating process. It is the schematic sectional drawing which shows an example of a slot die.

Hereinafter, the method for producing the laminate of the present disclosure will be described in detail.
In the present disclosure, the term "process" is included in the term not only in an independent process but also in the case where the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes.

In the present disclosure, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
When the reference numerals described in a plurality of drawings are the same, they refer to the same object. In addition, description of overlapping configurations and symbols in the drawings may be omitted.
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

In the present disclosure, the "solid content" refers to a component other than the solvent contained in the coating liquid. Further, the solvent means water, an organic solvent, or a mixture thereof.
In the present disclosure, the "viscosity" means the viscosity at a liquid temperature of 25 ° C.

Conventionally, a method of producing a laminate having a thin layer on a base material using a slot die has been known. In the case of this method, for example, step unevenness occurs due to a change in the distance between the slot die and the base material, or, for example, the meniscus of the coating liquid formed on the upstream side in the base material transport direction of the die (that is,). Coating streaks may occur due to the influence of the movement of the curved surface at the gas-liquid interface.
In particular, the step unevenness and coating streaks generated in the thin layer have a large effect on the manufactured laminated body, and from the viewpoint of suppressing deterioration of the functions and performance required for the laminated body, the step unevenness and coating streaks can be reduced. The current situation is that it is desired.
Therefore, the present inventor investigated a method for suppressing the occurrence of the above-mentioned step unevenness and coating streaks, and found that in the coating step, a coating liquid having no or little solid content was used to form a target thin layer. We have found a method for performing multi-layer coating, which is applied as a lower layer of the coating liquid.
Then, in this multi-layer coating, the present inventor sets the amount of underbite (that is, the difference (d1-d2) described later) to a specific range and satisfies the relationship d2> 3 × h described later to make it thin and thin. It was found that a coating layer in which the occurrence of step unevenness and coating streaks is suppressed can be obtained.

Based on the above findings, the method for producing the laminate of the present disclosure is as follows.
That is, the method for producing a laminate of the present disclosure is a step of simultaneously applying a plurality of coating liquids including a first coating liquid and a second coating liquid onto a substrate that is continuously conveyed using a slot die (hereinafter, It has at least a "multi-layer coating step"), and the first coating liquid is a coating liquid that is applied in contact with the substrate, and the second coating liquid is applied adjacent to the first coating liquid. The ratio A / B of the solid content A of the first coating liquid to the solid content B of the second coating liquid is 0.1 or less, and the slot for applying the second coating liquid is used. The difference (d1-d2) between the shortest distance d1 between the downstream lip surface in the base material transport direction and the base material and the shortest distance d2 between the upstream lip surface in the base material transport direction and the base material is 10 μm or more. Yes, the relationship between the shortest distance d2 and the thickness h of the coating film formed from the first coating liquid satisfies d2> 3 × h.

Here, "applying at the same time" means applying a plurality of coating liquids including the first coating liquid and the second coating liquid with one slot die. That is, when there are a plurality of coating liquids to be applied simultaneously with one slot die, the plurality of coating liquids include the first coating liquid and the second coating liquid. The plurality of coating liquids may be only the first coating liquid and the second coating liquid, or may be three or more coating liquids including the first coating liquid and the second coating liquid.
For example, when the first coating liquid, the second coating liquid, and the third coating liquid are applied on the base material with the first slot die, and the fourth coating liquid is applied with the second slot die, the present invention is used. The plurality of coating liquids to be "applied at the same time" in the multi-layer coating step in the disclosure are the first coating liquid, the second coating liquid, and the third coating liquid.

According to the method for producing a laminate of the present disclosure, it is possible to obtain a laminate having a thin layer on a substrate in which the occurrence of coating streaks and step unevenness is suppressed.

In the method for producing a laminate of the present disclosure, the solid content of the first coating liquid is much smaller than that of the second coating liquid, and the coating layer formed from the first coating liquid (that is, the coating film after drying). ) Also has a smaller thickness than the coating layer formed from the second coating liquid (that is, the coating film after drying). Therefore, the coating layer formed from the first coating liquid is difficult to function as a substantial layer, and the coating layer formed from the second coating liquid is formed on the base material.
That is, in the method for producing the laminate of the present disclosure, although the multi-layer coating step using the first coating liquid and the second coating liquid is performed, substantially, from the target second coating liquid on the base material. It can be said that this is a method of forming the formed coating layer as a single layer.
In the method for producing a laminate of the present disclosure, since both the first coating liquid and the second coating liquid are applied, for example, in order to form a second coating liquid (that is, a target coating layer). The size of the coating bead of the second coating liquid is smaller than that in the case where only the coating liquid) is applied. Therefore, it is considered that it is not easily affected by the change in the distance between the slot die and the base material, and as a result, the occurrence of step unevenness in the coating layer formed from the second coating liquid can be suppressed.
Further, since the first coating liquid is applied in contact with the base material, the influence of the movement of the meniscus (curved surface at the gas-liquid interface) of the coating liquid formed on the upstream side in the substrate transport direction of the slot die is affected. , It stays up to the first coating liquid, and it is difficult to reach the second coating liquid applied adjacent to the first coating liquid. As a result, it is considered that the influence of the above-mentioned movement of the meniscus and the like is blocked by the first coating liquid, so that the generation of step unevenness and coating streaks in the coating layer formed from the second coating liquid can be suppressed. ..

In addition, in the method for producing a laminate of the present disclosure, the shortest distance d1 (also simply referred to as a distance d1) between the downstream lip surface in the substrate transport direction and the substrate in the slot for applying the second coating liquid and the base. The difference (d1-d2) between the shortest distance d2 (also simply referred to as the distance d2) between the upstream lip surface in the material transport direction and the base material is 10 μm or more.
The difference (d1-d2) is also referred to as the amount of underbite, and when this value is 10 μm or more, the ease of applying the second coating liquid and the thinning of the coating film by the second coating liquid can be achieved. ..
Further, in the method for producing a laminate of the present disclosure, the relationship between the distance d2 and the thickness h of the coating film formed from the first coating liquid satisfies d2> 3 × h.
By satisfying this relationship d2> 3 × h, the pressure of the first coating liquid is suppressed, the propagation of disturbance to the second coating liquid is weakened, and the step unevenness that occurs in the coating film formed from the second coating liquid. Can be reduced.

The above-mentioned methods described in JP-A-2002-059062, JP-A-2013-220385, and JP-A-2013-052329 are: (1) the first coating liquid to be applied on a substrate. The solid content is 10% by mass or less of the solid content of the first coating film, (2) the difference (d1-d2), which is also called the underbite amount, is 10 μm or more, and (3) the distance. The relationship between d2 and the thickness h of the coating film does not satisfy all of satisfying d2> 3 × h.
Further, Japanese Patent Application Laid-Open No. 2002-059062, Japanese Patent Application Laid-Open No. 2013-220385, and Japanese Patent Application Laid-Open No. 2013-052329 do not have a technical idea of performing multi-layer coating for forming a target single layer, and further, this Of course, it has not been studied to obtain a thin layer (single layer) in which the occurrence of coating streaks and step unevenness is suppressed by the technique.

[Multi-layer coating process]
(Applying device)
In the method for producing a laminate of the present disclosure, a multi-layer coating step using a slot die is performed. The coating apparatus applied to the multi-layer coating process will be described with reference to the drawings.
Here, FIG. 1 is a schematic cross-sectional view showing an example of a coating device having a slot die.

As shown in FIG. 1, the coating device 100 includes a backup roll 110 that rotates while supporting the base material 120, and a slot die 130 that coats the base material 120 with the first coating liquid 140a and the second coating liquid 140b. Be prepared.
As the base material 120, for example, a base material such as a polymer film described later is applied.

The backup roll 110 is a member that is rotatably configured and can be continuously transported by winding a base material, and is rotationally driven at the same speed as the transport speed of the base material 120.
As the backup roll 110, a known one can be used without particular limitation.
As the backup roll 110, for example, one having a hard chrome-plated surface can be preferably used.
The thickness of the plating is preferably 40 μm to 60 μm from the viewpoint of ensuring conductivity and strength.
The surface roughness of the backup roll is preferably 0.1 μm or less in terms of surface roughness Ra from the viewpoint of reducing the variation in the frictional force between the base material 120 and the backup roll 110.

The backup roll 110 is heated from the viewpoint of enhancing the drying promotion of the coating film and from the viewpoint of suppressing brushing of the coating film due to a decrease in the film surface temperature (that is, whitening of the coating film due to the occurrence of fine dew condensation). May be.
The surface temperature of the backup roll 110 may be determined according to the composition of the coating film, the curing performance of the coating film, the heat resistance of the base material 120, and the like, and is preferably 30 ° C. to 130 ° C., preferably 40 ° C. to 100 ° C. Is more preferable.

It is preferable that the backup roll 110 detects the surface temperature and the surface temperature of the backup roll 110 is maintained by the temperature control means based on the temperature.
The temperature control means of the backup roll 110 includes a heating means and a cooling means. Induction heating, water heating, oil heating and the like are used as the heating means, and cooling with cooling water is used as the cooling means.

The diameter of the backup roll 110 is preferably 100 mm to 1000 mm, more preferably 100 mm to 800 mm, from the viewpoint of easy winding of the base material 120, easy layer coating with a slot die, and the manufacturing cost of the backup roll 110. It is preferable, and more preferably 200 mm to 700 mm.

The transport speed of the base material 120 on the backup roll 110 is preferably 10 m / min to 100 m / min from the viewpoint of ensuring productivity and coatability.

The lap angle of the base material 120 with respect to the backup roll 110 is preferably 60 ° or more, more preferably 90 ° or more, from the viewpoint of stabilizing the transport of the base material 120 at the time of coating and suppressing the occurrence of uneven thickness of the coating film. .. Further, the upper limit of the lap angle may be less than 360 °, and can be set to, for example, 180 °.
The lap angle refers to an angle including a transport direction of the base material 120 when the base material 120 comes into contact with the backup roll 110 and a transport direction of 120 when the base material 120 separates from the backup roll 110. ..

The slot die 130 is composed of a plurality of blocks 132A, 132B, 132C. By combining a plurality of blocks 132A, 132B, 132C, slots 134a and 134b, which are flow paths of the coating liquid, and pockets 136a and 136b for storing the coating liquid are formed inside the slot die 130. ..
Specifically, the blocks 132A and 132B form a pocket 136a for storing the first coating liquid 140a, and a slot 134a which is a flow path of the first coating liquid 140a extending from the pocket 136a to the tip of the slot die 130. , Are formed. Similarly, the blocks 132B and 132C provide a pocket 136b for storing the second coating liquid 140b and a slot 134b which is a flow path of the second coating liquid 140b extending from the pocket 136b to the tip of the slot die 130. It is formed.
That is, the coating device 100 has a slot 134a as a slot for applying the first coating liquid 140a and a slot 134b as a slot for applying the second coating liquid 140b.

The pockets 136a and 136b are storage spaces for the coating liquid whose cross-sectional shape is extended in the width direction of the slot die 130 (that is, the direction perpendicular to the transport direction of the base material 120). The shape of the pockets 136a and 136b does not matter as long as the coating liquid can be stored, and as shown in FIG. 1, the cross-sectional shape may be substantially circular or semicircular.

The lip surface, which is the tip surface of the slot die 130, is a surface facing the base material 120.
As shown in FIG. 2, the lip surface exists for each of the three blocks 132A, 132B, 132C, and the most upstream flow in the transport direction of the base material 120 (hereinafter, unless otherwise specified, upstream, downstream, upstream side, The description of the downstream side means the upstream (side) and the downstream (side) with respect to the transport direction of the base material 120), and the lip surfaces are 138A, 138B, and 138C.
In the coating device 100, the lip surface 138C is the downstream lip surface in the slot 134b for applying the second coating liquid 140b, and the lip surface 138B is the upstream lip surface in the slot 134b for applying the second coating liquid 140b. The lip surface 138B becomes the downstream lip surface in the slot 134a for applying the first coating liquid 140a, and the lip surface 138A becomes the upstream lip surface in the slot 134a for applying the first coating liquid 140a.

The coating device 100 has a difference (d) between the distance d1 between the downstream lip surface 138C and the base material 120 and the distance d2 between the upstream lip surface 138B and the base material 120 in the slot 134b where the second coating liquid 140b is applied. The slot die 130 is designed so that d1-d2) is 10 μm or more, and the relationship between the distance d2 and the thickness h of the coating film 122 formed from the first coating liquid 140a satisfies d2> 3 × h. Is used.

The above difference (d1-d2) and d2> 3 × h will be described with reference to FIG. In addition, in FIG. 2, in order to distinguish the thickness "h" of the coating film 122 formed from the first coating film 140a from the thickness "h2" of the coating film 124 formed from the second coating film 140b. , "H1" are also written.
As shown in FIG. 2, the difference (d1-d2) is based on the distance d1 between the downstream lip surface 138C and the surface of the base material 120 in the slot 134b to which the second coating liquid 140b is applied, and the upstream lip surface 138B. This is the difference from the distance d2 from the surface of the material 120.
The difference (d1-d2), which is also called the amount of underbite, is 10 μm or more, preferably 15 μm or more.
By setting the difference (d1-d2) to 10 μm or more, for example, it is easy to form a coating film having a thickness of 5 μm or less.
The upper limit of the difference (d1-d2) may be determined by the viscosity of the second coating liquid, the coating amount, the transport speed of the base material 120, and the like. For example, 300 μm or less is preferable, and the occurrence of coating streaks is suppressed. 200 μm or less is more preferable from the viewpoint of facilitating the operation.

Further, as shown in FIG. 2, the relationship between the distance d2 and the thickness h (h1) of the coating film 122 formed from the first coating liquid 140a satisfies d2> 3 × h (h1).
By setting the relationship between the distance d2 and the thickness h (h1) of the coating film 122 as d2> 3 × h (h1), step unevenness of the coating film 122 formed from the second coating liquid 140b, which is the upper layer, is reduced. it can.
The relationship between the distance d2 and the thickness h (h1) of the coating film 122 is preferably d2> 4 × h (h1), more preferably d2> 5 × h (h1).
Here, the value of the distance d2 is determined according to the coating amount of the first coating liquid, but when it is desired to apply the first coating liquid thinly (that is, when the coating amount of the first coating liquid is small), for example, The distance d2 can be set to 1 mm or less, preferably 500 μm or less. By reducing the value of the distance d2, the thickness h (h1) of the coating film 122 formed from the first coating liquid 140a can be easily set to, for example, 10 μm or less.

Here, the distance d1 and the distance d2 are measured as follows, respectively.
That is, the distance d2 can be measured with a taper gauge.
Further, for the distance d1, the difference between the distance d1 and the distance d2 (that is, the difference (d1-d2)) is measured by using the step measurement function of the measuring microscope, and the obtained measured value is measured by the above method. It is obtained by adding it to the measured value of.

Further, the thickness of the coating film by the first coating liquid (h (h1) in FIG. 2) and the thickness of the coating film by the second coating liquid (h2 in FIG. 2) are measured as follows.
Here, the thickness h (h1) and the thickness h2 are formed by forming a single coating film of each of the second coating liquid and the first coating liquid on the base material under the same conditions as in the case of multi-layer coating. It is obtained by measuring the thickness of the coating film with an optical interference type film thickness meter.
As the optical interference type film thickness meter, for example, an infrared spectroscopic interference type film thickness meter SI-T80 manufactured by KEYENCE Corporation can be used.
The measurement position is such that the coating film with the first coating liquid is 100 mm away from the downstream end of the block (block 132B in FIGS. 1 and 2) forming the slot for applying the first coating liquid in the substrate transport direction. The position where the coating film with the first coating liquid is applied is 100 mm away from the downstream end of the block (block 132B in FIGS. 1 and 2) forming the slot for applying the first coating liquid in the substrate transport direction. And.

In the present disclosure, the distance d1 is preferably 100 μm to 500 μm from the viewpoint of ease of coating, ease of device design, and the like.
The distance d2 is preferably 50 μm to 1 mm, preferably 50 μm to 500 μm, from the viewpoint of ease of coating, ease of device design, and the like.

In the present disclosure, the thickness h (h1) of the coating film by the first coating liquid is defined from the viewpoint of easily forming a coating film in which the occurrence of step unevenness and coating streaks is suppressed, and from the viewpoint of solvent removability and the like. For example, 1 μm to 15 μm is preferable.
Further, the thickness h2 of the coating film by the second coating liquid may be determined according to the film thickness of the target coating layer, and is set in the range of, for example, 1 μm to 15 μm.

Here, the coating device 100 shown in FIG. 1 has a configuration having three blocks 132A, 132B, 132C, two pockets 136a, 136b, and two slots 134a, 134b, but the number of blocks is three. The number of pockets and slots formed by combining blocks is not limited to one, and the number of pockets and slots formed by combining blocks is not limited to two.
That is, as a coating device applicable to the method for producing a laminate of the present disclosure, a required number of pockets and slots are formed by four or more blocks according to the type and number of coating films required. It may be an embodiment.

When the coating apparatus applicable to the method for producing a laminate of the present disclosure has four blocks and the number of pockets and slots formed by combining the four blocks is three, the first coating liquid and the first coating liquid and the first coating apparatus. In addition to the 2 coating liquid, the 3rd coating liquid is used.
In this coating apparatus, the "difference (d1-d2)" when the first coating liquid and the second coating liquid and these coating liquids are applied, and the "distance d2 and the thickness h of the coating film formed from the first coating liquid". "Relationship with" is as described above. With this configuration, the pressure of the first coating liquid is suppressed, the propagation of disturbance to the second coating liquid and the third coating liquid is weakened, and the coating film and the third coating formed from the second coating liquid are weakened. It is possible to reduce the step unevenness that occurs in the coating film formed from the liquid.
The third coating liquid is a coating liquid that is applied adjacent to the second coating liquid. The thickness of the slot for applying the third coating liquid and the coating film formed from the third coating liquid is not particularly limited, but the following aspects are preferable.
That is, in the slot for applying the third coating liquid, the shortest distance d0 between the downstream lip surface in the base material transport direction and the base material, and the shortest distance d1 between the upstream lip surface in the base material transport direction and the base material. The difference (d0-d1) is preferably 10 μm or more. With such a configuration, the ease of coating the third coating liquid and the thinning of the coating film by the third coating liquid can be achieved.
The above aspect is preferable even when the number of blocks and the number of pockets and slots are further increased and the types of coating liquid are increased.

[First coating liquid and second coating liquid]
In the multi-layer coating step in the present disclosure, the first coating liquid and the second coating liquid are used.
The first coating liquid is a coating liquid that is applied in contact with the substrate.
The second coating liquid is a coating liquid that is applied adjacent to the first coating liquid, and is a coating liquid used to form a target coating layer.
The ratio A / B of the solid content content A of the first coating liquid to the solid content content B of the second coating liquid is 0.1 or less.
As the second coating liquid, from the viewpoint that a thin layer can be formed by the method for producing a laminate of the present disclosure, for example, a coating liquid for forming a hard coat layer, a liquid crystal layer, a refractive index adjusting layer, etc. in an optical film is used. Can be mentioned.

(Second coating liquid)
The solid content content B in the second coating liquid may be determined according to the type, viscosity, etc. of the target coating layer.
Above all, for example, from the viewpoint of forming a coating layer in which the occurrence of step unevenness and coating streaks is suppressed, the solid content content B is, for example, 5% by mass to 50% by mass with respect to the total mass of the second coating liquid. It is preferably in the range of%.

The viscosity of the second coating liquid is preferably, for example, in the range of 0.4 mPa · s to 3 mPa · s from the viewpoint of forming a coating layer in which the occurrence of step unevenness and coating streaks is suppressed.
Here, the viscosity of the second coating liquid is measured by a B-type viscometer, a vibration-type viscometer, or the like, but in the present disclosure, the value measured by the B-type viscometer is adopted.

Here, as an example of the second coating liquid, a coating liquid for forming a hard coat layer (hereinafter, also referred to as a coating liquid for forming a hard coat layer) will be described, but the present disclosure is not limited to this aspect. Absent.
The hard coat layer is preferably formed by a cross-linking reaction or a polymerization reaction of an ionizing radiation curable compound. That is, it is preferable that the coating liquid for forming the hard coat layer contains, for example, a polymerizable compound such as a monomer or an oligomer, a polymerization initiator, and a solvent.
As the polymerizable compound, a compound exhibiting polymerizability with active energy rays such as light, electron beam, and radiation is preferable, and among them, a compound exhibiting photopolymerizability is preferable.
Examples of the polymerizable compound exhibiting photopolymerizability include compounds having an unsaturated double bond such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group, and among them, a compound having a (meth) acryloyl group is used. preferable.

-Compounds with unsaturated double bonds-
Examples of the compound having an unsaturated double bond include a monomer, an oligomer, a polymer, and the like, and among them, a polyfunctional monomer having two or more (preferably three or more) unsaturated double bonds is preferable.

Examples of the polyfunctional monomer having two or more unsaturated double bonds include (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, and (meth) acrylic acid diesters of polyhydric alcohol. Examples include (meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, etc., among which polyhydric alcohols (Meta) acrylic acid diesters are preferable.

Specific examples of the polyfunctional monomer having two or more unsaturated double bonds include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol. Di (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modification Trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified trimethylphosphate (meth) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropane tetra (meth) acrylate, dipenta Erislitol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocia Nurate and the like can be mentioned.

The compound having an unsaturated double bond can be used alone or in combination of two or more.
The content of the compound having an unsaturated double bond in the coating liquid for forming a hard coat layer is the total solid content in the coating liquid for forming a hard coat layer from the viewpoint of imparting a sufficient polymerization rate to impart hardness and the like. On the other hand, 40% by mass to 98% by mass is preferable, and 60% by mass to 95% by mass is more preferable.

-Polymerization initiator-
The coating liquid for forming a hard coat layer preferably contains a polymerization initiator.
The polymerization initiator is preferably a photopolymerization initiator, for example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyl. Examples thereof include dione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, lofin dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes and coumarins.
Specific examples of the photopolymerization initiator, preferred embodiments, commercially available products, and the like are described in paragraphs [0133] to [0151] of JP-A-2009-098658, and can be preferably used in the present disclosure as well. it can.
In addition, as a polymerization initiator, "Latest UV Curing Technology" {Technical Information Association Co., Ltd.} (1991), p. 159 and "Ultraviolet Curing System" by Kiyomi Kato (published by General Technology Center in 1989), p. Various examples are also described in 65 to 148, and these can also be used.

The polymerization initiator may be used alone or in combination of two or more.
The content of the polymerization initiator in the composition for the hard coat layer is set to a sufficiently small amount so as to polymerize the polymerizable compound contained in the composition for the hard coat layer and not to increase the starting points too much. From the viewpoint of the above, 0.5% by mass to 8% by mass is preferable, and 1% by mass to 5% by mass is more preferable with respect to the total solid content in the composition for the hard coat layer.

-Organic solvent-
The coating liquid for forming a hard coat layer may contain various organic solvents as a solvent.
As the organic solvent, an ether solvent, a ketone solvent, an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent and the like can be used.
Specifically, for example, dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetol, methylethylketone (also known as MEK). ), Diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone (also called anon), methylcyclohexanone, methylisobutylketone, 2-octanone, 2-pentanone, 2-hexanone, ethylene glycol ethyl ether, ethylene glycol Examples thereof include isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol, hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, toluene and xylene.

Further, it is preferable to contain, for example, a hydrophilic solvent other than the above. As the hydrophilic solvent, an alcohol solvent, a carbonate solvent, or an ester solvent may be used.
Specifically, for example, methanol, ethanol, isopropanol, n-butyl alcohol, cyclohexyl alcohol, 2-ethyl-1-hexanol, 2-methyl-1hexanol, 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol. , Diacetone alcohol, dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, methyl ethyl carbonate, methyl n-propyl carbonate, ethyl formate, propyl acetate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, propionic acid Ethyl, ethyl 2-ethoxypropionate, methyl acetoacetate, ethyl acetoacetate, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, acetone, 1,2-diacetoxyacetone, acetylacetone, ethylene glycol mono Examples thereof include butyl acetate, propylene glycol monomethyl ether acetate (also referred to as PGMEA), and diethylene glycol acetate.

As the organic solvent, one type alone or two or more types can be used in combination.
The solvent in the coating liquid for forming the hard coat layer is preferably used so that the solid content of the coating liquid for forming the hard coat layer is in the range of 20% by mass to 80% by mass. That is, the content of the solvent in the coating liquid for forming the hard coat layer is preferably 20% by mass to 80% by mass, more preferably 25% by mass to 70% by mass, based on the total mass of the coating liquid for forming the hard coat layer. It is preferable, and 30% by mass to 60% by mass is more preferable.

-Surfactant-
The coating liquid for forming a hard coat layer may contain a surfactant.
The surfactant is not particularly limited, but a fluorine-based surfactant and a silicone-based surfactant are preferable. Further, the surfactant is preferably a high molecular compound rather than a low molecular compound.

As the surfactant, one type alone or two or more types can be used in combination.
The content of the surfactant is preferably 0.01% by mass to 0.5% by mass, preferably 0.01% by mass to 0.3% by mass, based on the total solid content of the coating liquid for forming the hard coat layer. Is more preferable.

-Other ingredients-
The coating liquid for forming the hard coat layer may contain other components such as inorganic particles, resin particles, a monomer for adjusting the refractive index, and a conductive compound.

The coating liquid for forming a hard coat layer is not limited to the above composition, and for example, the coating liquid described in Japanese Patent No. 5933353, Japanese Patent No. 5331919, etc. may be applied.

(First coating liquid)
The first coating liquid is a coating liquid having a solid content content A. In the present disclosure, the ratio A / B of the solid content content A of the first coating liquid to the solid content content B of the second coating liquid is 0.1 or less.
That is, the solid content content A of the first coating liquid is 1/10 or less of the solid content content B of the second coating liquid.
In particular, from the viewpoint of considering the influence on the coating layer formed from the second coating liquid, the smaller the solid content is, the better. Specifically, the solid content A of the first coating liquid is preferably 1/20 or less of the solid content B of the second coating liquid, and 1/100 or less of the solid content B of the second coating liquid. Is more preferable, and it is particularly preferable that the solid content content of the first coating liquid is 0% by mass (that is, the second coating liquid consists only of the solvent).

The first coating liquid is a coating liquid containing 90% by mass or more of the solvent with respect to the total mass of the first coating liquid from the viewpoint of considering the influence on the coating layer formed from the second coating liquid. Is preferable. The content of the solvent in the first coating liquid is more preferably 95% by mass or more, further preferably 99% by mass or more, and particularly preferably 100% by mass.
Here, the solvent contained in the first coating liquid is not particularly limited, and a known organic solvent can be applied in addition to water. Specific examples of the organic solvent include the organic solvent applied to the above-mentioned coating liquid for forming a hard coat layer.
The organic solvent contained in the first coating liquid may be used alone or in combination of two or more.

As the organic solvent contained in the first coating liquid, it is preferable to use an organic solvent having a boiling point of 80 ° C. or lower as at least a part thereof from the viewpoint of removability of the coating film formed from the first coating liquid. Examples of organic solvents having a boiling point of 80 ° C. or lower include tetrahydrofuran (boiling point: 66 ° C.), acetone (boiling point: 56 ° C.), methyl ethyl ketone (boiling point: 80 ° C.), n-hexane (boiling point): 69 ° C.), benzene (boiling point: 56 ° C.). 80 ° C.), methyl acetate (boiling point: 57 ° C.), ethyl acetate (boiling point: 77 ° C.), ethanol (boiling point: 78 ° C.) and the like.
As the organic solvent contained in the first coating liquid, an organic solvent having a boiling point of 80 ° C. or lower and another organic solvent may be combined so as to satisfy a preferable range of viscosity of the first coating liquid described later. preferable.

The solid content contained in the first coating liquid is preferably the same as the solid content contained in the second coating liquid from the viewpoint of reducing the influence on the coating layer formed from the second coating liquid, and is of the same type. Is more preferable.
For example, when the second coating liquid is the coating liquid for forming a hard coat layer as described above, the solid content contained in the first coating liquid is preferably a polymerizable compound, a polymerization initiator, and if necessary, used. Other components such as those mentioned above, preferably containing one or more of them.

Further, it is preferable that the first coating liquid is an organic solvent having a single solvent from the viewpoint of improving the coating property.
As the single organic solvent, it is preferable to use an organic solvent that satisfies the preferable range of the viscosity of the first coating liquid described later, and examples thereof include propylene glycol monomethyl ether acetate (viscosity 1.1 mPa · s).

From the viewpoint of reducing the influence on the coating layer formed from the second coating liquid, it is preferable that at least a part of the solvent contained in the first coating liquid is the same as the solvent contained in the second coating liquid.
For example, when the second coating liquid contains methyl ethyl ketone as a solvent, it is preferable that methyl ethyl ketone is contained as at least a part of the solvent contained in the first coating liquid.

As for the viscosity of the first coating liquid, the smaller the value (that is, the larger the difference in viscosity from the second coating liquid), the more advantageous it is for thinning the coating film formed from the first coating liquid. is there.
Therefore, the viscosity of the first coating liquid is preferably 2 mPa · s or less, preferably 1.8 mPa · s or less, from the viewpoint of facilitating the formation of a thin film coating film having excellent coatability and removability. It is more preferable that the thickness is 1.5 mPa · s or less.
The viscosity of the first coating liquid is preferably 0.5 mPa · s or more, more preferably 0.8 mPa · s or more, and 1.0 mPa · s or more, from the viewpoint of disturbance resistance of the coating bead. The above is more preferable.
Here, the viscosity of the first coating liquid is also measured by the same method as the viscosity of the second coating liquid.

[Application conditions]
The multi-layer coating step in the present disclosure can be performed under the following coating conditions.
For example, the temperature at which the first coating liquid and the plurality of coating liquids including the second coating liquid are discharged from the slot die may be appropriately determined according to the composition of the coating liquid, the ease of coating, and the like. Often, for example, each is set in the range of 15 ° C to 40 ° C.
Further, the coating amount of the plurality of coating liquids including the first coating liquid and the second coating liquid when discharged from the slot die may be determined according to the set thickness of the coating film, for example. each ^of which is set in a range of ^{5ml / m 2 ~50ml / m 2} .

By going through the multi-layer coating step as described above, a coating film in which the occurrence of coating streaks and step unevenness is suppressed (that is, a coating film formed from the second coating liquid) is formed.

In the method for producing a laminate of the present disclosure, in addition to the above-mentioned multi-layer coating step, a drying step of reducing the solvent from the coating film formed in the multi-layer coating step and a coating film after the drying step are irradiated with active energy rays. It may have a curing step of curing the coating film or the like.

[Drying process]
In the drying step, the solvent is reduced from the coating film formed in the multi-layer coating step.
The drying means used in the drying step is not particularly limited, and examples thereof include a method using an oven, a hot air blower, an infrared (IR) heater, and the like.
In drying with a warm air blower, warm air may be blown from a surface opposite to the coating film forming surface of the base material, or a diffusion plate may be installed so that the coating film does not flow with warm air.
The drying conditions may be determined according to the type of the formed coating film, the coating amount, the transport speed, and the like. For example, the drying conditions are preferably carried out in the range of 30 ° C. to 140 ° C. for 10 seconds to 10 minutes.

[Curing process]
In the curing step, the coating film after the drying step is irradiated with active energy rays to cure the coating film.
The means for irradiating the active energy rays used in the curing step is not particularly limited as long as it is a means for imparting energy capable of generating active species in the coating film to be irradiated.
Specific examples of the active energy rays include α-rays, γ-rays, X-rays, ultraviolet rays, infrared rays, visible rays, and electron beams. Of these, ultraviolet rays are preferably used as the active energy rays from the viewpoint of curing sensitivity and availability of equipment.

Examples of the ultraviolet light source include tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps, mercury xenon lamps, carbon arc lamps and other lamps, and various lasers (eg, semiconductor lasers, helium neon lasers, argon ions). Examples include lasers, helium cadmium lasers, YAG (Yttrium Aluminum Garnet) lasers), light emitting diodes, and cathode wire tubes.
The peak wavelength of ultraviolet rays emitted from the light source of ultraviolet rays is preferably 200 nm to 400 nm.
As the exposure energy amount of ultraviolet rays, for ^{example, 100mJ / cm 2 ~500mJ / cm} 2 is preferred.

From the above, it is possible to manufacture a laminate in which a coating layer formed from the second coating liquid is provided on the base material.

[Laminate]
The laminate obtained by the method for producing a laminate of the present disclosure has a base material and a coating layer formed from a second coating liquid.

(Base material)
The base material can be appropriately selected depending on the use of the laminate, and examples thereof include a polymer film.
For optical film applications, the light transmittance of the base material is preferably 80% or more.
For optical film applications, when a polymer film is used as the base material, it is preferable to use an optically isotropic polymer film.
Examples of the base material include a polyester-based base material (film or sheet of polyethylene terephthalate, polyethylene naphthalate, etc.), a cellulose-based base material (film or sheet of diacetyl cellulose, triacetyl cellulose (TAC), etc.), and a polycarbonate-based base material. , Poly (meth) acrylic base material (film or sheet such as polymethyl methacrylate), polystyrene base material (film or sheet such as polystyrene, acrylonitrile styrene copolymer), olefin base material (polyethylene, polypropylene, cyclic or Polyamide having a norbornene structure, film or sheet of ethylene-propylene copolymer, etc.), polyamide-based substrate (film or sheet of polyvinyl chloride, nylon, aromatic polyamide, etc.), polyimide-based substrate, polysulfone-based substrate, poly Ethersulfone-based base material, polyether ether ketone-based base material, polyphenylene sulfide-based base material, vinyl alcohol-based base material, polyvinylidene chloride-based base material, polyvinyl butyral-based base material, poly (meth) acrylate-based base material, polyoxy Examples thereof include a transparent base material such as a methylene-based base material and an epoxy resin-based base material, and a base material made of a blended polymer blended with the above polymer materials.

The base material may be one in which a layer is formed in advance on the above polymer film.
Examples of the layer formed in advance include an adhesive layer, a barrier layer against water, oxygen and the like, a refractive index adjusting layer and the like.

(Layer formed from the second coating liquid)
The coating layer formed from the second coating liquid is not particularly limited, and examples thereof include a hard coat layer, a liquid crystal layer, and a refractive index adjusting layer for optical film applications.
The thickness of the layer formed from the second coating liquid varies depending on the application, but by adopting the method for producing a laminate of the present disclosure, for example, 0.1 μm to 100 μm, more preferably 0.1 μm. It can be in the range of ~ 5 μm.

(Other layers)
On the coating layer formed from the second coating liquid, another layer may be further provided depending on the intended use.
The other layers are layers formed by coating with the same slot die as the slot die to which the second coating liquid is applied (that is, a coating layer formed by coating at the same time as the second coating liquid in the multi-layer coating process). It may be a coating layer formed by coating with a slot die different from the slot die to which the second coating liquid is applied.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.

(Preparation of base material)
As a base material, a long triacetyl cellulose (TAC) film (TD40UL, FUJIFILM Corporation, refractive index 1.48) having a thickness of 60 μm and a width of 1490 mm was prepared.

(Coating liquid for forming a hard coat layer 1: Preparation of the second coating liquid 1)
The mixture of each component described below is put into a mixing tank, stirred, filtered through a polypropylene filter having a pore size of 0.4 μm, and coated with a coating liquid for forming a hard coat layer (solid content content: 50% by mass, viscosity 2. 9 mPa · s) was prepared.

− Coating liquid for forming a hard coat layer 1-
-Polymerizable compound: Pentaerythritol tetraacrylate (NK ester of Shin Nakamura Chemical Industry Co., Ltd.): 48.4% by mass
-Photopolymerization initiator: Omnirad 184 (IGM Resins BV): 1.5% by mass
-Surfactant: Fluorine-based surfactant shown below: 0.1% by mass
-Organic solvent: Methyl ethyl ketone: 50% by mass

(Coating liquid 2: for forming a hard coat layer: Preparation of the second coating liquid 2)
The mixture of each component described below is put into a mixing tank, stirred, filtered through a polypropylene filter having a pore size of 0.4 μm, and coated with a coating liquid for forming a hard coat layer (solid content content: 50% by mass, viscosity 3. 6 mPa · s) was prepared.

− Coating liquid for forming a hard coat layer 2-
-Polymerizable compound: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.): 48.5% by mass
-Photopolymerization initiator: Omnirad 907 (IGM Resins BV): 1.5% by mass
-Organic solvent: Methyl ethyl ketone: 35% by mass
-Organic solvent: Cyclohexanone: 15% by mass

(Preparation of 1st coating liquids 1 to 9)
The first coating liquids 1 to 9 were prepared using the components listed in Table 1 below (when a plurality of components were used, they were mixed).
The first coating liquids 6 to 9 contain the solid content contained in the second coating liquid 1 in the same composition ratio, and only the solid content content A is changed (that is, the second coating liquid described above). Liquid 1 is a coating liquid obtained by diluting the liquid 1 with the organic solvent shown in Table 1 below so as to have the solid content content A shown in Table 1 below).
The solid content and viscosity are also shown in Table 1.
The viscosity is a value measured by the above method.

The details of the components listed in Table 1 are as follows.
-MEK: Methyl ethyl ketone-Anone: Cyclohexanone-PGMEA: Propylene glycol monomethyl ether acetate

(Examples 1 to 13 and Comparative Examples 1 to 4)
(Multi-layer coating process)
Layer coating was performed on the TAC film using the coating apparatus shown in FIG.
Specifically, the base material is conveyed onto a backup roll having an outer diameter of 300 mm, and the slot die shown in FIG. 1 is used for the base material on the backup roll, and the first coating liquid and the second coating liquid shown in Table 2 are used. The coating liquid was applied. At this time, the lap angle of the base material was 150 °.
The distance d1, the distance d2, the thickness h (h1), and the thickness h2 at this time are as shown in Table 2.
Further, in the multi-layer coating step, the temperature at the time of discharging the coating liquid was 23 ° C., the coating width was 1300 mm, and the coating speed (that is, the transport speed) was 10 m / min.

(Drying process and curing process)
Subsequently, after the coating film was dried at 60 ° C. for 1 minute, the coating film was cured by irradiating with ^{ultraviolet rays at an exposure energy of 200 mJ / cm 2.}
As a result, a hard coat layer having a thickness of 5 μm was formed.
The TAC film on which the hard coat layer was formed was wound into a roll.

As described above, the laminate of each example was produced.

(Evaluation: Evaluation of coating streaks and step unevenness)
The distance from the end (the end on the winding end side) of the laminate produced above to 1 m to 10 m was set as an observation target. The laminated body to be observed was placed on a light table, the laminated body was exposed to transmitted light, and the presence or absence of repeated shading or shading was visually observed to evaluate coating streaks and step unevenness.
The evaluation indexes are as follows.

-Evaluation index of coating streaks-
1: No coating streaks are seen.
2: The coating streaks were observed to be extremely weak.
3: Application streaks were observed with 1 or more and less than 5 streaks.
4: Application streaks were observed on the entire surface.

-Evaluation index of step unevenness-
1: No step unevenness is seen.
2: Step unevenness was observed very weakly.
3: Step unevenness was observed.
4: Step unevenness was strongly observed.

As shown in Table 2, it can be seen that, according to the production methods of the examples, a laminated body having a coating layer in which the occurrence of step unevenness and coating streaks is suppressed can be obtained.

[Explanation of code]
100 Coating device 110 Backup roll 120 Base material 122 Coating film formed from the first coating film 124 Coating film formed from the second coating film 130 Slot dies 132A, 132B, 132C Block 134a, 134b Slot 136a, 136b Pocket 138A, 138B, 138C Lip surface 140a 1st coating liquid 140b 2nd coating liquid d1 Shortest distance between the downstream lip surface and the surface of the base material in the slot for applying the 2nd coating liquid d2 In the slot for applying the 2nd coating liquid The shortest distance between the upstream lip surface and the surface of the base material h (h1) Thickness of the coating film formed from the first coating film h2 Thickness of the coating film formed from the second coating film

The disclosure of Japanese application 2018-154088, filed August 20, 2018, is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims (6)

It has at least a step of simultaneously applying a plurality of coating liquids including the first coating liquid and the second coating liquid on the substrate to be continuously conveyed by using a slot die.
The first coating liquid is a coating liquid that is applied in contact with the base material.
The second coating liquid is a coating liquid that is applied adjacent to the first coating liquid.
The ratio A / B of the solid content content A of the first coating liquid to the solid content content B of the second coating liquid is 0.1 or less.
In the slot for applying the second coating liquid, the shortest distance d1 between the downstream lip surface in the base material transport direction and the base material and the shortest distance d2 between the upstream lip surface in the base material transport direction and the base material. The difference (d1-d2) is 10 μm or more,
A method for producing a laminate, wherein the relationship between the shortest distance d2 and the thickness h of the coating film formed from the first coating liquid satisfies d2> 3 × h. The method for producing a laminate according to claim 1, wherein the first coating liquid is a coating liquid having a viscosity of 2 mPa · s or less. The method for producing a laminate according to claim 1 or 2, wherein the first coating liquid is a coating liquid having a viscosity of 1 mPa · s or more. The method for producing a laminate according to any one of claims 1 to 3, wherein the first coating liquid is a coating liquid containing 90% by mass or more of a solvent with respect to the mass of the first coating liquid. The method for producing a laminate according to claim 4, wherein the solvent is a single organic solvent. The method for producing a laminate according to any one of claims 1 to 5, wherein at least a part of the solvent contained in the first coating liquid is the same as the solvent contained in the second coating liquid.

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