WO2022130902A1

WO2022130902A1 - Method for producing multilayer film and coating device

Info

Publication number: WO2022130902A1
Application number: PCT/JP2021/042650
Authority: WO
Inventors: 京久内海; 諭司國安
Original assignee: 富士フイルム株式会社
Priority date: 2020-12-17
Filing date: 2021-11-19
Publication date: 2022-06-23
Also published as: CN116600905A; CN116600905B; JPWO2022130902A1

Abstract

The present disclosure provides a method for producing a multilayer film, said method comprising: conveyance of a base material, which comprises a first surface and a second surface that is on the reverse side of the first surface, toward a coating device that comprises an ejection part which ejects a coating liquid; and application of the coating liquid to the first surface of the base material with use of the coating device, while floating and conveying the base material, in such a manner that the first surface of the base material faces the coating device, along a conveyance path that is curved above the coating device so as to protrude in the direction away from the coating device. The present disclosure also provides a coating device.

Description

Multilayer film manufacturing method and coating equipment

This disclosure relates to a method for manufacturing a multilayer film and a coating device.

The following Patent Document 1 includes an extrusion type coater head and a pair of gas ejection means for floating and guiding a web-shaped support on the upstream side and the downstream side of the coater head, and the coater head and a pair of gas ejection means. Disclosed is a coating device characterized by coating on a support traveling in between.

The following Patent Document 2 includes a backup body that supports a traveling web and a die head that applies a coating liquid to the web on the backup body, and is provided on the surface of the backup body with respect to the web along the width direction of the web. A plurality of air outlets are provided to discharge air, a blower is connected to each air outlet of the backup body via an air flow path, and a control valve is provided in the air flow path on the inlet side of each air outlet. It discloses a coating device characterized by the fact that.

In Patent Document 3 below, the coating liquid is continuously extruded from the slot tip onto the surface of a flexible support that runs continuously along the back edge surface and the doctor edge surface, and the coating liquid is applied to the surface of the support. Disclosed is a method for manufacturing a magnetic recording medium in which a magnetic coating liquid having a coating thickness of 4 μm or less is sequentially layered on a wet lower layer coating liquid previously coated by an extrusion type coating device.

Japanese Patent Application Laid-Open No. 2003-225604 Japanese Unexamined Patent Publication No. 2001-310148 Japanese Unexamined Patent Publication No. 5-208165

In Patent Document 1, the support is levitated by a pair of gas ejection means provided on the upstream side and the downstream side of the coater head, and the coater head runs between the coater head and the pair of gas ejection means. Apply the coating liquid to the support. However, at the coating point, the support is not directly supported by the pressure of the gas discharged from the gas ejection means, and the coating liquid is applied to the support running in a flat state, so that the support is the coating liquid. It is easily affected by the discharge pressure, and wrinkles are likely to occur on the running film. Therefore, the uniformity of the film thickness distribution of the coating film formed on the support may decrease.

In Patent Document 2, the web is supported by air discharged from the air outlet of the backup body at predetermined intervals from the backup body, and the die head is applied to the web running between the die head and the backup body. Apply the working liquid. However, the direction of the pressure applied to the web by the air discharged from the air outlet at the coating point is opposite to the direction of the pressure applied to the web by the coating liquid discharged from the die head, and the die head and the backup body are in the opposite direction. The web running between them is susceptible to the pressure of air and the pressure of the coating liquid acting in opposite directions as described above. Therefore, the uniformity of the film thickness distribution of the coating film formed on the web may decrease.

In Patent Document 3, the support runs so as to be pressed against the back edge surface and the doctor edge surface, and the discharge pressure of the coating liquid is applied to the support running along the back edge surface and the doctor edge surface. It grows to apply the liquid. When the discharge pressure of the coating liquid increases, the uniformity of the film thickness distribution of the coating film formed on the support may decrease.

One aspect of the present disclosure is to provide a method for producing a multilayer film capable of forming a coating film having a uniform film thickness distribution.
Another aspect of the present disclosure is to provide a coating device capable of forming a coating film having a uniform film thickness distribution.

The disclosure includes the following aspects:
<1> The base material containing the first surface and the second surface on the opposite side of the first surface is conveyed toward the coating device including the discharge portion for discharging the coating liquid, and the coating device is used. The coating device is used while floating and transporting the base material toward the coating device with the first surface of the base material along a transport path that is convexly curved in a direction away from the coating device. A method for producing a multilayer film, which comprises applying the coating liquid to the first surface of the base material.
<2> The floating transport of the base material is directed toward the first surface of the base material from a gas blowing portion arranged at least one of upstream and downstream of the discharge portion in the transport direction of the base material. The method for producing a multilayer film according to <1>, which comprises blowing out the gas.
<3> The method for producing a multilayer film according to <2>, which comprises controlling the floating amount of the base material by controlling the pressure of the gas blown out from the blowing portion.
<4> The floating transfer of the base material brings out the first blowout portion that blows out the gas arranged upstream of the discharge portion and the gas arranged downstream of the discharge portion in the transport direction of the base material. The gas is blown out from the second blowout portion toward the first surface of the base material, the pressure of the gas blown out from the first blowout portion, and the blowout from the second blowout portion. The method for producing a multilayer film according to <1>, which comprises controlling the pressure of the gas independently of each other.
<5> The pressure of the gas existing in the space between the base material and the first blowing portion is lower than the pressure of the gas existing in the space between the base material and the second blowing portion. The method for producing a multilayer film according to <4>.
<6> A coating device for applying a coating liquid to a substrate including a first surface being conveyed and a second surface on the opposite side of the first surface, wherein the first surface of the substrate is used. A discharge portion that discharges the coating liquid toward the surface and at least one of the discharge portions upstream and downstream of the discharge portion in the transport direction of the base material, and the first base material is used to float the base material. A coating device comprising at least one blowout portion, which blows gas toward a surface.

According to one aspect of the present disclosure, there is provided a method for producing a multilayer film capable of forming a coating film having a uniform film thickness distribution.
According to another aspect of the present disclosure, there is provided a coating device capable of forming a coating film having a uniform film thickness distribution.

FIG. 1 is a schematic side view for explaining a method for manufacturing a multilayer film according to an embodiment of the present disclosure. FIG. 2 is a schematic side view showing the tip of the coating device shown in FIG. 1 in an enlarged manner.

Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments. The following embodiments may be modified as appropriate within the scope of the purposes of the present disclosure.

When the embodiments of the present disclosure are described with reference to the drawings, the description of overlapping components and reference numerals may be omitted in the drawings. The components shown by the same reference numerals in the drawings mean that they are the same components. The dimensional ratio in the drawings does not necessarily represent the actual dimensional ratio.

In the present disclosure, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the lower limit value and the upper limit value, respectively. In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. 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.

In the present disclosure, the amount of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. ..

In the present disclosure, the term "process" is included in this term not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. ..

In this disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

In the present disclosure, "solid content" means a component other than a solvent.

<Manufacturing method of multilayer film>
The method for producing a multilayer film according to an embodiment of the present disclosure is a coating apparatus including a substrate including a first surface and a second surface on the opposite side of the first surface, and a discharge portion for discharging a coating liquid. (Hereinafter, may be referred to as a “transportation step”) and the above-mentioned base material along the conveying path curved in a convex direction above the coating device in a direction away from the coating device. Applying the coating liquid to the first surface of the base material using the coating device while floating and transporting the base material toward the coating device (hereinafter, "coating"). Sometimes referred to as "process"), including. According to the above-described embodiment, there is provided a method for producing a multilayer film capable of forming a coating film having a uniform film thickness distribution. In the present disclosure, the phrase "above the coating device" used in describing the relationship between an object and the coating device refers to the relative position of the object with respect to the coating device.

The presumed reason for forming a coating film with a uniform film thickness distribution is considered as follows. In contrast to the methods disclosed in Patent Document 1, Patent Document 2 and Patent Document 3, the method for producing a multilayer film according to an embodiment of the present disclosure is directed away from the coating device above the coating device. A coating liquid is applied to the first surface of the base material using the coating device while floating and transporting the base material toward the coating device along the transport path curved in a convex shape. Including applying. That is, the coating liquid discharged from the discharge portion of the coating device is applied to the first surface of the base material facing the discharge portion of the coating device, which is convexly curved in a direction away from the coating device by floating transfer. In the process of applying the coating liquid, the base material is convexly curved in the direction away from the coating device and floated and transported, so that the coating liquid can be applied to the base material with a low discharge pressure, and the base material has the discharge pressure of the coating liquid. It is also less susceptible. As a result, it is presumed that a coating film having a uniform film thickness distribution is formed.

Hereinafter, each process in the method for manufacturing a multilayer film will be specifically described.

<< Transfer process >>
In the transfer step, the base material containing the first surface and the second surface on the opposite side of the first surface is transferred toward the coating device including the discharge portion for discharging the coating liquid.

(Base material)
Examples of the components of the base material include polymers and metals. Examples of the polymer include polyethylene terephthalate, polyethylene naphthalate and triacetyl cellulose. The substrate may contain one or more polymers. Examples of the metal include iron, chromium, nickel, titanium, copper, aluminum, silver and gold. The metal may be an alloy. Examples of alloys include stainless steel and Invar. The substrate may contain one or more metals. In certain embodiments, the substrate preferably comprises a polymer and more preferably comprises at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate and triacetyl cellulose. In certain embodiments, the substrate preferably comprises a metal, more preferably comprising at least one selected from the group consisting of nickel, titanium, copper, aluminum, silver and gold, and the group consisting of copper and aluminum. It is more preferable to contain at least one selected from the above, and it is particularly preferable to contain aluminum.

The base material is preferably a film. Examples of the film include a film containing the above-mentioned polymer and a film containing the above-mentioned metal. Specific examples of the film containing the polymer include a polyethylene terephthalate film, a polyethylene naphthalate film, and a triacetyl cellulose film. Specific examples of the film containing metal include a copper film and an aluminum film.

The base material may have high thermal conductivity. Examples of the base material having high thermal conductivity include a base material having a thermal conductivity of 200 W / (m · K) or more. The upper limit of the thermal conductivity of the substrate is not limited. The thermal conductivity of the substrate may be 500 W / (m · K) or less. The thermal conductivity of the substrate is measured using a laser flash method. First, the substrate is cut out at three locations along the width direction (specifically, at a position 5 mm from both ends in the width direction and the center portion in the width direction) at φ5 mm to 10 mm to obtain three measurement samples. The thermal conductivity of each measurement sample is measured using a thermophysical property measuring device (for example, LFA-502, Kyoto Denshi Kogyo Co., Ltd.) to which the laser flash method is applied. The arithmetic mean of the three measured values is taken as the thermal conductivity of the substrate.

The layer structure of the base material is not limited. The base material may have a single-layer structure or a multi-layer structure.

From the viewpoint of improving productivity, the base material is preferably a long base material. The length of the base material is preferably 10 m or more, more preferably 100 m or more, and particularly preferably 200 m or more. The upper limit of the length of the substrate is not limited. The upper limit of the length of the base material may be 1,000 m or 500 m. The length of the substrate is usually in the range of 10 m to 1,000 m. The "base material length" means the distance from one end of the base material to the other in the transport direction of the base material.

The width of the base material is not limited. From the viewpoint of productivity and wrinkle suppression, the width of the base material is preferably in the range of 100 mm to 1,800 mm, more preferably in the range of 300 mm to 1,600 mm, and 500 mm to 1,400 mm. It is particularly preferable that it is within the range.

The thickness of the base material is not limited. From the viewpoint of handleability, the thickness of the base material is preferably in the range of 3 μm to 50 μm, and more preferably in the range of 10 μm to 30 μm.

(Transport)
The substrate is transported using, for example, a known transport device. The transport device may include a tension control mechanism that controls the tension of the base material. Examples of the transfer device include a transfer roller and a transfer belt. Further, examples of the transfer device include a delivery device for sending out a base material and a winding device for winding up the base material. The sending device and the winding device are also used, for example, as a roll-to-roll type transfer device. The roll-to-roll type transport device is preferably used as a device for transporting a long base material.

The transport speed of the base material is preferably in the range of 1 m / min to 100 m / min.

The tension of the base material is preferably in the range of 30 N / m to 300 N / m, and more preferably in the range of 50 N / m to 200 N / m. Tension control is performed using, for example, a known tension control device. Tension control may be performed using a known transfer device including a tension control mechanism. Examples of the transfer device including the tension control mechanism include a transfer device including a Tendency Drive Roller. The tendency-driven roller is rotated by, for example, a frictional force or a magnetic force acting between a rotating shaft supporting the tendency-driven roller and the tendency-driven roller. The axis of rotation is rotated by, for example, a motor. That is, the force for rotating the rotation shaft is transmitted to the tendency-driven roller, and the tendency-driven roller rotates. The transport device including the tendency-driven roller can control the tension of the film according to the rotation speed of the rotating shaft, for example. Techniques relating to tendency-driven rollers are described, for example, in Japanese Patent No. 4066904. The contents of the above documents are incorporated herein by reference. Tension control may be performed using dancer rollers. Tension control may be performed using a rotary draw control method.

(Applying device)
The coating device includes a discharge unit that discharges the coating liquid. The coating device may include a plurality of ejection portions. Examples of the component of the discharge portion include metal. Examples of the metal include stainless steel. As long as the discharge portion has a function of discharging the coating liquid, the structure of the discharge portion is not limited. The discharge unit may include one or more discharge ports. Examples of the shape of the discharge port in a plan view include a circular shape, an elliptical shape, a polygonal shape, a linear shape, and an amorphous shape. From the viewpoint of making the film thickness distribution of the coating film uniform, it is preferable that the discharge portion includes a discharge port extending in the width direction of the base material.

The coating device preferably includes a blowout portion that blows out gas. The coating device may include one or more outlets. The blowout portion supplies gas between the substrate and the coating device. The gas supplied between the base material and the coating device supports the base material in the coating step described later, and floats the base material from the coating device. Examples of the component of the discharge portion include metal. Examples of the metal include stainless steel. As long as the blowout portion has the function of blowing out the gas, the structure of the blowout portion is not limited. The outlet may include one or more outlets. Examples of the shape of the outlet in a plan view include a circle, an ellipse, a polygon, a linear shape, and an amorphous shape. The blowout portion may include a space (that is, a flow path) through which the gas flows, which communicates with the discharge port. The blowing portion may be a nozzle. The blowout portion may be a porous body.

As will be described later, the coating device applies the coating liquid to the conveyed substrate. The coating device that applies the coating liquid to the conveyed base material has a discharge portion that discharges the coating liquid toward the first surface of the base material and upstream and downstream of the discharge portion in the transport direction of the base material. It is preferable to include at least one blowing portion, which is arranged on at least one of the above and blows gas toward the first surface of the base material in order to float the base material. According to the above-described embodiment, there is provided a coating device capable of forming a coating film having a uniform film thickness distribution. It is preferable that the blowout portion is arranged upstream and downstream of the discharge portion in the transport direction of the base material, respectively. A blowout portion arranged upstream of the discharge portion in the transport direction of the base material (hereinafter, may be referred to as a "first blowout portion") and a blowout portion arranged downstream of the discharge portion in the transport direction of the base material. The portion (hereinafter, may be referred to as a “second blowout portion”) stabilizes the floating transport of the base material and improves the uniformity of the film thickness distribution of the coating film. The first blowout portion may or may not be adjacent to the discharge portion. The second ejection portion may or may not be adjacent to the ejection portion. It is preferable that the first blowing portion is adjacent to the discharging portion and the second blowing portion is adjacent to the discharging portion.

<< Coating process >>
In the coating step, the coating device is floated and transported with the first surface of the substrate toward the coating device along a transport path that is convexly curved in a direction away from the coating device above the coating device. Use to apply the coating solution to the first surface of the substrate. According to the coating process as described above, a coating film having a uniform film thickness distribution is formed.

(Floating transport)
In the coating process, the substrate is floated and transported above the coating device. That is, the base material is conveyed without contacting the coating device. The floating amount of the base material is determined, for example, according to the coating conditions (for example, the type of coating liquid). From the viewpoint of stabilizing the floating transport and making the film thickness distribution of the coating film uniform, the floating amount of the base material is preferably 10 μm or more, and more preferably 20 μm or more. The lower limit of the floating amount of the base material may be 50 μm or 100 μm. From the viewpoint of preventing the coated bead from becoming unstable due to the influence of gravity, the floating amount of the base material is preferably 1,000 μm or less, more preferably 500 μm or less, and 400 μm or less. Is particularly preferable. The floating amount of the base material is preferably in the range of 10 μm to 1,000 μm, more preferably in the range of 20 μm to 500 μm, and particularly preferably in the range of 50 μm to 400 μm. The "flying amount of the base material" means the shortest distance between the first surface of the base material and the surface of the discharge portion facing the first surface of the base material. The floating amount of the base material is measured by using a laser displacement meter according to the following procedures (1) to (3). The floating amount of the base material is measured under the condition excluding the influence of the coating liquid, that is, the condition that the coating liquid is not applied to the base material.
(1) Using a laser displacement meter arranged facing the ejection part of the coating device, the position of the surface of the ejection portion is detected, and then the ejection portion of the coating device and the laser are carried while floating and transporting the base material. The position of the second surface of the base material running between the displacement meter and the displacement meter is detected.
(2) Based on the measurement result obtained in (1) above, the distance D from the surface of the ejection portion to the second surface of the floating base material is measured.
(3) The value obtained according to the following formula is regarded as the floating amount of the base material.
Formula: Floating amount of base material = [Distance D]-[Thickness of base material]

The degree of bending of the base material in the coating process is represented by, for example, the radius of curvature. The larger the degree of bending, the smaller the radius of curvature, and the smaller the degree of bending, the larger the radius of curvature. From the viewpoint of making the film thickness distribution of the coating film uniform, the radius of curvature of the base material at the contact point between the base material and the coating liquid is preferably in the range of 50 mm to 1,000 mm, and in the range of 70 mm to 600 mm. It is more preferable that it is in the range of 100 mm to 300 mm, and it is particularly preferable that it is in the range of 100 mm to 300 mm. The radius of curvature of the base material is measured under the condition excluding the influence of the coating liquid, that is, the condition that the coating liquid is not applied to the base material.

The method of ascending the base material is not limited. Examples of the method of floating the base material include a method of supplying gas between the base material and the coating device. The gas supplied between the substrate and the coating device supports the substrate and floats the substrate from the coating device. When the base material is supported by the gas, the coating liquid can be applied to the base material at a lower discharge pressure, further improving the uniformity of the film thickness distribution of the coating film.

The type of gas is not limited. Examples of the gas include nitrogen and air. The gas is preferably air.

The gas is supplied, for example, by a known method. The gas may be supplied using a blower, a compressor or a container (eg, a cylinder) for storing the gas.

Gas pressure is not limited. The pressure of the gas affects, for example, the amount of floating of the base material and the degree of bending of the base material. The larger the gas pressure, the larger the floating amount of the base material, and the smaller the gas pressure, the smaller the floating amount of the base material. Further, the greater the pressure of the gas, the greater the degree of bending of the base material, and the smaller the pressure of the gas, the smaller the degree of bending of the base material. From the viewpoint of stabilizing floating transport and bending the base material, the pressure of the gas existing in the space between the base material and the coating device (hereinafter, may be referred to as “P0”) shall be 10 Pa or more. Is preferable, 50 Pa or more is more preferable, and 100 Pa or more is particularly preferable. The "gas existing in the space between the base material and the coating device" is not only the gas intentionally supplied between the base material and the coating device, but also the space between the base material and the coating device. Includes gases (eg, atmosphere) that are present due to unintentional factors. Further, P0 is preferably 150 Pa or more, and more preferably 200 Pa or more. The smaller the pressure fluctuation of the gas, the more uniform the film thickness distribution of the coating film is. From the viewpoint of reducing the pressure fluctuation of the gas, P0 is preferably 2,000 Pa or less, more preferably 1,600 Pa or less, and particularly preferably 1,300 Pa or less. The upper limit of P0 may be 1,000 Pa, 800 Pa or 500 Pa. P0 is preferably in the range of 10 Pa to 2,000 Pa, more preferably in the range of 100 Pa to 1,600 Pa, and particularly preferably in the range of 150 Pa to 1,300 Pa. P0 is measured by inserting a metal tube connected to a manostar gauge into the space between the substrate and the coating device.

The floating transfer of the base material includes blowing the gas toward the first surface of the base material from the blowout portion arranged at least one of the upstream side and the downstream side of the discharge part in the transfer direction of the base material. Is preferable. The gas blown from the blowout portion toward the first surface of the base material supports the base material and floats the base material from the coating device. The method as described above stabilizes the floating transport of the base material and improves the uniformity of the film thickness distribution of the coating film. From the viewpoint of stabilizing the floating transport, it is preferable that the blowout portion is arranged upstream and downstream of the discharge portion in the transport direction of the base material, respectively. The blowout portion may be a part of the coating device or an element independent of the coating device. The blowout portion is preferably part of the coating device. Aspects of the blowout portion are described in the above-mentioned "Transport step" section.

It is preferable that the method for producing a multilayer film according to an embodiment of the present disclosure includes controlling the floating amount of the base material by controlling the pressure of the gas blown out from the blowing portion. The pressure of the gas blown out from the blowout portion is controlled, for example, within the range of the pressure described above (that is, P0). The levitation amount of the base material is controlled, for example, within the range of the levitation amount described above.

The floating transfer of the base material is performed from the first blowing portion that blows out the gas arranged upstream of the discharging portion and the second blowing portion that blows out the gas arranged downstream of the discharging portion in the transport direction of the base material. To control the pressure of the gas blown out from the first blowout portion and the pressure of the gas blown out from the second blowout portion independently of each other, and to blow out the gas toward the first surface of the base material. , Are preferably included. The method as described above stabilizes the floating transport of the base material and improves the controllability of the degree of bending of the base material. As a result, the uniformity of the film thickness distribution of the coating film is improved. The pressure of the gas existing in the space between the base material and the first blowing portion (hereinafter, may be referred to as “P1”) is the gas existing in the space between the base material and the second blowing portion. It may be the same as or different from the pressure of (hereinafter, may be referred to as “P2”). The "gas existing in the space between the base material and the blowout portion" is not only the gas intentionally supplied between the base material and the blowout portion, but also the space between the base material and the blowout portion. Includes gases (eg, atmosphere) that are present due to unintentional factors. P1 and P2 are controlled, for example, within the pressure range described above (ie, P0). From the viewpoint of making the film thickness distribution of the coating film uniform, the ratio of P1 to P2 (that is, P1 / P2) is preferably 0.1 to 1.5, and more preferably 0.3 to 1. preferable. P1 is preferably lower than P2. When P1 is lower than P2, the influence of the tension fluctuation of the base material on the film thickness distribution of the coating film is small, and the uniformity of the film thickness distribution of the coating film is also improved. From the above viewpoint, the ratio of P1 to P2 (that is, P1 / P2) is preferably 0.1 or more and less than 1, more preferably 0.3 to 0.9, and 0.4 to 0.9. It is particularly preferably 0.8. P1 is preferably 50 Pa or more lower than P2, and more preferably 100 Pa or more lower than P2. For example, P1 is preferably in the range of 10 Pa to 250 Pa, and P2 is preferably in the range of 300 Pa to 500 Pa. P1 is measured by inserting a metal tube connected to a manostar gauge into the space between the substrate and the first outlet. P2 is measured by inserting a metal tube connected to a manostar gauge into the space between the substrate and the second outlet.

(Application)
Examples of the coating method include a curtain coating method, a dip coating method, a spin coating method, a printing coating method, a spray coating method, a slot coating method, a roll coating method, a slide coating method, a blade coating method, a gravure coating method and a wire bar method. Can be mentioned. In the coating step, it is preferable to apply the coating liquid by the slot coating method. In the slot coating method, for example, the coating liquid is discharged from a discharge portion including a discharge port extending in the width direction of the base material.

The thickness of the coating liquid applied to the base material (hereinafter, may be referred to as "thickness of liquid film") is not limited. The thickness of the liquid film may be in the range of 10 μm to 200 μm. The thickness of the liquid film may be in the range of 20 μm to 100 μm.

(Coating liquid)
The type of coating liquid is not limited. The type of coating liquid is determined, for example, according to the use of the multilayer film. The coating liquid is preferably a water-based coating liquid. The "water-based coating liquid" means a coating liquid in which the solvent contained in the coating liquid is substantially water. "The solvent contained in the coating liquid is substantially water" means that water occupies most of the solvent contained in the coating liquid. The ratio of water to the solvent contained in the water-based coating liquid is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

Examples of the water contained in the water-based coating liquid include natural water, purified water, distilled water, ion-exchanged water, pure water and ultrapure water.

The water content in the water-based coating liquid is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total mass of the water-based coating liquid. The water content in the water-based coating liquid is preferably less than 100% by mass, more preferably 80% by mass or less, based on the total mass of the water-based coating liquid.

The water-based coating liquid may contain particles. Examples of the particles include inorganic particles, organic particles, and composite particles of an inorganic substance and an organic substance.

Examples of the inorganic particles include metal particles, semi-metal particles, metal compound particles, semi-metal compound particles, inorganic pigment particles, mineral particles and polycrystalline diamond particles. Examples of the metal include alkali metals, alkaline earth metals, transition metals and alloys thereof. Examples of metalloids include silicon. Examples of metal compounds and metalloid compounds include oxides, hydroxides and nitrides. Examples of the inorganic pigment include carbon black. Examples of minerals include mica.

Examples of the organic particles include resin particles and organic pigment particles.

As the composite particles of the inorganic substance and the organic substance, for example, the composite particles in which the inorganic particles are dispersed in the matrix of the organic substance, the composite particles in which the periphery of the organic particles is coated with the inorganic substance, and the periphery of the inorganic particles are the organic substances. Examples thereof include composite particles coated with.

The particles may be surface-treated to impart dispersibility. Composite particles may be formed by surface treatment.

The particle size, specific gravity and usage pattern of the particles are not limited. The particle size, specific gravity, and usage pattern of the particles are determined, for example, according to the coating film formed by the coating liquid and the production conditions of the coating film.

The water-based coating liquid may contain one kind or two or more kinds of particles.

The content of particles in the water-based coating liquid is not limited. The content of particles in the water-based coating liquid is determined, for example, according to the purpose of adding the particles, the coating film formed by the coating liquid, and the production conditions of the coating film.

Examples of the components of the water-based coating liquid include a binder component, a component that contributes to the dispersibility of particles, a polymerizable compound, a polymerization initiator, and a component for enhancing coating performance (for example, a surfactant).

The solid content concentration of the coating liquid is preferably less than 70% by mass, more preferably 30% by mass to 60% by mass.

<< Other processes >>
The method for producing a multilayer film according to an embodiment of the present disclosure may include steps other than the above-mentioned steps, if necessary.

(Drying process)
The method for producing a multilayer film according to an embodiment of the present disclosure may include drying the coating liquid after the coating step. That is, the coating liquid applied to the substrate may be dried. Examples of the drying method include heating and blowing. The temperature of the gas in the blast is preferably in the range of 25 ° C to 200 ° C, more preferably in the range of 30 ° C to 150 ° C. The wind speed in blowing air is preferably 1.5 m / sec to 50 m / sec. Examples of the drying device used for drying the coating liquid include an oven, a hot air blower, and an infrared heater.

(Multilayer film cutting process)
The method for producing a multilayer film according to an embodiment of the present disclosure may include a step of cutting the multilayer film. The width of the multilayer film can be adjusted by cutting the multilayer film. Examples of the method for cutting the multilayer film include a method using a blade.

<< Production method >>
From the viewpoint of improving productivity, the method for producing a multilayer film according to one embodiment of the present disclosure is preferably carried out by a roll-to-roll method. In the method for producing a multilayer film carried out by the roll-to-roll method, at least a transfer step and a coating step are carried out between the supply of the rolled film and the winding of the film.

Next, an example of a method for manufacturing a multilayer film will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic side view for explaining a method for manufacturing a multilayer film according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing an enlarged tip of the coating device shown in FIG. In FIG. 2, the direction X is orthogonal to the direction Y.

The manufacturing apparatus 100 shown in FIG. 1 includes a transfer roller 10, a transfer roller 11, a transfer roller 12, a transfer roller 13, a transfer roller 14, a transfer roller 15, a transfer roller 16, a transfer roller 17, a transfer roller 18, and a coating device 20. Includes a drying device 30, a sending device (not shown) and a winding device (not shown).

The transfer roller 10, the transfer roller 11, the transfer roller 12, the transfer roller 13, the transfer roller 14, the transfer roller 15, the transfer roller 16, the transfer roller 17, and the transfer roller 18 transfer the film F while supporting the film F. Each roller is rotatable. The film F is a base material containing the first surface F1 and the second surface F2 on the opposite side of the first surface F1.

The coating device 20 applies the coating liquid to the conveyed film F. The coating device 20 includes a discharge portion 21, a first blowout portion 22, and a second blowout portion 23.

The discharge unit 21 discharges the coating liquid L toward the first surface F1 of the film F. The discharge unit 21 includes a discharge port 21a. The discharge port 21a extends in the width direction of the film F, that is, in the direction orthogonal to the direction X and the direction Y. The coating liquid L is supplied from a liquid feeding device (not shown) connected to the coating device 20, and is discharged through the discharge port 21a.

The first blowing portion 22 blows gas toward the first surface F1 of the film F. The first blowing portion 22 is arranged upstream of the discharging portion 21 in the transport direction of the film F. The first blowing portion 22 is adjacent to the discharging portion 21. The first outlet 22 includes a plurality of outlets 22a. The gas is supplied from a compressor (not shown) connected to the coating device 20 and blown out through the outlet 22a.

The second blowing portion 23 blows gas toward the first surface F1 of the film F. The second blowing portion 23 is arranged downstream of the discharging portion 21 in the transport direction of the base material F. The second blowing portion 23 is adjacent to the discharging portion 21. The second outlet 23 includes a plurality of outlets 23a. The gas is supplied from a compressor (not shown) connected to the coating device 20 and blown out through the outlet 23a.

The drying device 30 dries the coating liquid L coated on the film F.

The delivery device (not shown) supplies the film F from the roll film RF1. The delivery device mounts the roll film RF1 along a rotation axis extending from the front to the back of FIG.

The winding device (not shown) winds the multilayer film containing the film F into a roll to form the roll film RF2. The take-up device mounts the roll film RF2 along the rotation axis extending from the front to the back of FIG.

The method for manufacturing the multilayer film shown in FIG. 1 is carried out by a roll-to-roll method. The film F sent out from the roll film RF1 includes a transfer roller 10, a transfer roller 11, a transfer roller 12, a transfer roller 13, a transfer roller 14, a coating device 20, a transfer roller 15, a drying device 30, a transfer roller 16, and a transfer roller 17. And, it passes through the transport roller 18 and is wound into a roll.

As shown in FIG. 1, the film F sent out from the roll film RF1 is conveyed toward the coating device 20. As shown in FIG. 2, the film F that has reached the coating device 20 is levitated and transported along a transport path that is convexly curved in the direction Y away from the coating device 20 above the coating device 20. The film F that is levitated and conveyed is supported by the gas that is blown out from the first blowout portion 22 and the second blowout portion 23. The first surface F1 of the film F that is floated and conveyed faces the coating device 20. The coating device 20 applies the coating liquid L to the first surface F1 of the film F which is floated and conveyed as described above. The coating liquid L is applied to the first surface F1 of the film F which is convexly curved in the direction Y away from the coating device 20 by floating transfer. As shown in FIG. 2, the film F is floated and conveyed by being convexly curved in the direction Y away from the coating device 20 by the gas blown from the first blowing portion 22 and the second blowing portion 23. The coating liquid L can be applied to the film F with a low discharge pressure. As a result, it is presumed that the uniformity of the distribution of the coating liquid L coated on the film F is improved, and a coating film having a uniform film thickness distribution is formed.

The coating liquid applied to the film F is dried in the drying device 30. A multilayer film is formed by drying the coating liquid. The multilayer film is wound into a roll using a winding device (not shown). The multilayer film wound into a roll forms the roll film RF2.

Hereinafter, the present disclosure will be described in detail by way of examples. However, the present disclosure is not limited to the following examples.

<Example 1>
(Preparation of base material AL1)
As the base material AL1, an aluminum film having a width of 220 mm, a thickness of 10 μm, a length of 300 m, and a thermal conductivity of 230 W / (m · K) was prepared. The base material AL1 is rolled into a roll to form a roll film.

(Preparation of coating liquid A)
The following components were mixed to prepare a coating liquid A.
-Polyvinyl alcohol (CKS-50, degree of saponification: 99 mol%, degree of polymerization: 300, Nippon Synthetic Chemical Industry Co., Ltd.): 58 parts by mass-Serogen PR (Daiichi Kogyo Seiyaku Co., Ltd.): 24 parts by mass-Surfactant Agent (Nippon Emulsion Co., Ltd., Emarex 710): 5 parts by mass, Art Pearl (registered trademark) J-7P aqueous dispersion: 913 parts by mass

The aqueous dispersion of Art Pearl J-7P was prepared by the following method. To 74 parts by mass of pure water, 3 parts by mass of Emarex 710 (Nippon Emulsion Co., Ltd., nonionic surfactant) and 3 parts by mass of sodium carboxymethyl cellulose (Daiichi Kogyo Seiyaku Co., Ltd.) were added. To the obtained aqueous solution, 20 parts by mass of Art Pearl J-7P (Negami Kogyo Co., Ltd., silica composite crosslinked acrylic resin fine particles) was added, and 10,000 rpm (revolutions per minute) was added using an ace homogenizer (Nissei Tokyo Office Co., Ltd.). , The same applies hereinafter) for 15 minutes to obtain an aqueous dispersion of Artpearl J-7P (particle concentration: 20% by mass). The true specific gravity of the silica composite crosslinked acrylic resin fine particles in the obtained aqueous dispersion is 1.20, and the average particle size of the fine particles is 6.5 μm.

(Manufacturing of multilayer film)
The coating liquid A was applied to the base material AL1 using a manufacturing apparatus including the components as shown in FIG. 1, and then the coating liquid was dried. A multilayer film was obtained by the above procedure. The transport speed of the film is 20 m / min. Specific manufacturing conditions are shown in Table 1.

<Examples 2 to 7>
A multilayer film was obtained by the same procedure as in Example 1 except that the production conditions were changed according to the description in Table 1.

<Comparative Example 1>
The coating liquid A was applied to the base material AL1 using a coating apparatus as shown in FIG. 1 of JP-A-5-208165, and then the coating liquid was dried. A multilayer film was obtained by the above procedure. The transport speed of the film is 20 m / min. Specific manufacturing conditions are shown in Table 1.

<Comparative Example 2>
According to the embodiment shown in FIG. 1 of JP-A-2001-310148, the coating liquid A is applied to the base material AL1 running between the backup roller used as the blowing portion for blowing air and the coating device, and then the coating liquid A is applied. The coating liquid was dried. A multilayer film was obtained by the above procedure. The transport speed of the film is 20 m / min. Specific manufacturing conditions are shown in Table 1.

<Evaluation>
(Film thickness distribution)
Using a film thickness measuring instrument (SI-T90, KEYENCE CORPORATION), the thickness of the coating film in the longitudinal direction of the multilayer film was measured at 10 points every 5 mm. The film thickness distribution T of the coating film was calculated and evaluated according to the following criteria. The evaluation results are shown in Table 1.
A: T ≤ 1%
B: 1% <T <2%
C: 2% ≤ T <5%
D: 5% ≤ T

A description of the items listed in Table 1 is shown below.
“Discharge unit” indicates a discharge unit that discharges the coating liquid.
The “blowout portion” indicates a blowout portion that blows out a gas (specifically, air). The blowing portion in Comparative Example 2 is a backup roller that blows out gas.
"The shortest distance between the discharge part and the base material" indicates the shortest distance between the discharge part and the base material being conveyed, which is measured under the condition that the coating liquid is not applied to the base material. Further, the "shortest distance between the ejection portion and the base material" according to Examples 1 to 7 corresponds to the floating amount of the base material described above.
The "shortest distance between the blowout portion and the base material" indicates the shortest distance between the blowout portion and the base material being conveyed, which is measured under the condition that the coating liquid is not applied to the base material.
“P0” indicates the pressure of the gas existing in the space between the base material and the blowout portion.
“P1” indicates the pressure of the gas existing in the space between the base material and the first blowing portion.
“P2” indicates the pressure of the gas existing in the space between the base material and the second blowing portion.

Table 1 shows that the uniformity of the film thickness distribution in Examples 1 to 7 is superior to that in Comparative Examples 1 and 2. In Comparative Example 1 with respect to Examples 1 to 7, it is considered that the uniformity of the film thickness distribution was lowered because the base material was not floated and conveyed by the gas. In Comparative Example 2 with respect to Examples 1 to 7, since the base material floated and conveyed between the backup roller for blowing gas and the coating device is convexly curved in the direction from the backup roller to the coating device. It is considered that the uniformity of the film thickness distribution has decreased.

The disclosure of Japanese Patent Application No. 2020-209440 filed on December 17, 2020 is incorporated herein by reference. All documents, patent applications and technical standards described herein are to the same extent as if it were specifically and individually stated that the individual documents, patent applications and technical standards are incorporated by reference. Incorporated by reference in the book.

10, 11, 12, 13, 14, 15, 16, 17, 18: Conveying roller 20: Coating device 21: Discharge unit 21a: Discharge port 22: First outlet 23:

Second outlet

22a, 23a: Outlet 30: Drying device 100: Manufacturing device F: Film F1: First surface F2: Second surface RF1, RF2: Roll film

Claims

To convey the base material containing the first surface and the second surface on the opposite side of the first surface toward the coating device including the discharge portion for discharging the coating liquid.
The base material is floated and transported with the first surface of the base material directed toward the coating device along a transport path that is convexly curved in a direction away from the coating device above the coating device. The present invention comprises applying the coating liquid to the first surface of the substrate using a coating apparatus.
A method for manufacturing a multilayer film.
The floating transport of the base material is such that the gas is directed toward the first surface of the base material from a blowout portion that blows out a gas arranged at least one of upstream and downstream of the discharge portion in the transport direction of the base material. The method for producing a multilayer film according to claim 1, which comprises blowing out.
The method for producing a multilayer film according to claim 2, wherein the floating amount of the base material is controlled by controlling the pressure of the gas blown out from the blowing portion.
The floating transport of the base material blows out a first blowout portion that blows out a gas arranged upstream of the discharge portion and a second blowout portion of a gas arranged downstream of the discharge portion in the transport direction of the base material. The gas is blown from the blowing portion toward the first surface of the base material, the pressure of the gas blown from the first blowing portion, and the pressure of the gas blown from the second blowing portion. The method for producing a multilayer film according to claim 1, wherein the pressure is controlled independently of each other.
4. The pressure of the gas existing in the space between the base material and the first blowing portion is lower than the pressure of the gas existing in the space between the base material and the second blowing portion. The method for producing a multilayer film according to the above.
A coating device for applying a coating liquid to a substrate including a first surface being conveyed and a second surface on the opposite side of the first surface.
A discharge portion that discharges the coating liquid toward the first surface of the base material,
At least one blowout portion that is arranged at least one of upstream and downstream of the discharge portion in the transport direction of the base material and blows gas toward the first surface of the base material in order to levitate the base material. And, including,
Coating device.