Method for producing laminated body

Abstract

A method for manufacturing a laminated body comprises the following steps: for a substrate being continuously conveyed on a conveying path, coating a first coating liquid on a first surface of the substrate is started, while the solid content concentration of the first coating liquid film formed by the first coating liquid is between 40% by mass and 80% by mass, coating a second coating liquid on a second surface opposite to the first surface of the substrate is started, coating the second coating liquid on the second surface in a region where the substrate is being conveyed along a conveying path bent by applying pressure to the first surface side by gas, and the misalignment amount between the width of the first coating liquid film on the first surface and the width of the second coating liquid film formed by the second coating liquid on the second surface is within 1 mm.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminated body. Background Art

[0002] In a roll-to-roll continuous process, there is known a method for producing a laminated body in which a target film is formed on both sides of a strip-shaped substrate (i.e., a first side and a second side opposite to the first side) and arranged in the order of film, substrate, and film.

[0003] In addition, as a method for producing a laminated body, for example, there is a method of applying a coating liquid for obtaining a target film on a substrate and drying the obtained coating liquid film.

[0004] As an example of a method for manufacturing a laminate, Japanese Patent Gazette No. 2004-344693 discloses a sequential coating method for performing coating and drying steps on both sides of a support, wherein a coating liquid is coated on the surface of a traveling belt-shaped plastic support, and the coated coating film is dried at a temperature substantially above the glass transition point temperature of the support.

[0005] In addition, Japanese Patent Gazette No. 2-119968 discloses a method in which a coating liquid is applied to the first surface of a sheet, the coating liquid applied to the first surface is cooled to promote gelation, and then the first surface (i.e., the coating surface) is floated and supported by a gas jet while the coating liquid is applied to the second surface (the surface opposite to the first surface) in a continuous state. Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] For example, as described in Japanese Patent Publication No. 2004-344693, there is a method for manufacturing a laminate, which includes the following steps: for a continuously conveyed substrate, after starting to apply the coating liquid to the first side of the substrate, the coating liquid is applied to the second side opposite to the first side of the substrate, and the coating liquid is applied on both sides of the substrate in sequence. In this manufacturing method, curling sometimes occurs at the width direction end of the substrate at the stage of drying the coating liquid film formed on the first side. In addition, the curling generated at this stage sometimes makes it difficult to form a desired coating liquid film on the second side. For example, when curling occurs at the above-mentioned stage, it is sometimes impossible to reduce the offset amount of the width of the coating liquid film formed on the first side and the width of the coating liquid film formed on the second side. As a result, curling sometimes also occurs in the obtained laminate (specifically, a laminate with a dried film).

[0008] Therefore, the problem to be solved by one embodiment of the present invention is to provide a method for manufacturing a laminate, which method includes the following steps: for a continuously conveyed substrate, after starting to apply the coating liquid on the first surface of the substrate, starting to apply the coating liquid on the second surface opposite to the first surface of the substrate, and being able to obtain a laminate in which the misalignment between the width of the coating liquid film formed on the first surface and the width of the coating liquid film formed on the second surface is small and the curling is reduced.

[0009] Means for solving technical problems

[0010] Means for solving the above-mentioned problems include the following embodiments.

[0011] <1> A method for producing a laminate, comprising the following steps:

[0012] The first coating liquid is applied to the first surface of the substrate while the substrate is continuously transported on the transport path, and the second coating liquid is applied to the second surface of the substrate opposite to the first surface while the solid content concentration of the first coating liquid film formed by the first coating liquid is 40 mass % to 80 mass %,

[0013] The second coating liquid is applied to the second surface in a region where the substrate is being transported along a transport path bent by applying pressure to the first surface side by gas,

[0014] The misalignment amount between the width of the first coating liquid film on the first surface and the width of the second coating liquid film formed by the second coating liquid on the second surface is within 1 mm.

[0015] <2> The method for producing a laminate according to <1>, wherein:

[0016] The thickness of the substrate is 5 μm or more and 80 μm or less.

[0017] <3> The method for producing a laminate according to <1> or <2>, wherein:

[0018] The film thickness of the first coating liquid film and the second coating liquid film is 40 μm or more.

[0019] <4> The method for producing a laminate according to any one of <1> to <3>, wherein

[0020] The curvature radius of the curved conveying path is 100 mm to 500 mm.

[0021] <5> The method for producing a laminate according to any one of <1> to <4>, wherein

[0022] The distance of the curved conveying path is 350 mm to 1750 mm.

[0023] <6> The method for producing a laminate according to any one of <1> to <5>, wherein

[0024] The distance from the starting point of the bend of the conveying path to the application start point of the second coating liquid is 50±25% of the distance of the curved conveying path.

[0025] Effects of the Invention

[0026] According to one embodiment of the present invention, a method for manufacturing a laminate is provided, the method comprising the following steps: for a continuously conveyed substrate, after starting to apply a coating liquid on the first surface of the substrate, starting to apply the coating liquid on the second surface opposite to the first surface of the substrate, and being able to obtain a laminate in which the misalignment between the width of the coating liquid film formed on the first surface and the width of the coating liquid film formed on the second surface is small and the curling is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram showing each step of a method for producing a laminated body according to one embodiment.

[0028] Figure 2 It is a schematic cross-sectional view for explaining the curling amount of the width direction end part of a base material. DETAILED DESCRIPTION

[0029] Hereinafter, an embodiment of a method for producing a laminate will be described. However, the present invention is not limited to the following embodiment at all, and can be implemented with appropriate modifications within the scope of the purpose of the present invention.

[0030] In the present invention, a numerical range expressed by "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0031] In the numerical ranges recorded in stages in the present invention, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in the present invention, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiment.

[0032] Each element in each drawing shown in the present invention is not necessarily to exact scale, but the focus is on clearly illustrating the principle of the present invention, and there are also emphasized portions.

[0033] In addition, in each drawing, the same reference numerals are given to components having the same function, and duplicate descriptions are omitted.

[0034] In the present invention, the "substrate" refers to a substrate that is continuously conveyed and has a belt-like shape.

[0035] In the present invention, the "width direction" refers to a direction orthogonal to any longitudinal direction (ie, conveyance direction) of a continuously conveyed substrate (ie, a belt-shaped substrate), a coating liquid film, and a film.

[0036] In the present invention, the "first surface" of the substrate is one surface of the strip-shaped substrate, and unless otherwise specified, it refers to the surface on which the coating liquid is first applied. Furthermore, the "second surface" of the substrate is the other surface of the strip-shaped substrate, that is, the surface opposite to the first surface, and unless otherwise specified, it refers to the surface on which the coating liquid is applied later.

[0037] In the present invention, a combination of two or more preferred aspects or configurations is a more preferred aspect or configuration.

[0038] 《Method for producing laminated body》

[0039] As described above, for a continuously transported substrate, after the coating liquid is applied to the first surface of the substrate, the coating liquid is applied to the second surface opposite to the first surface of the substrate. In the case of double-sided coating by sequentially applying the coating liquid to both surfaces of the substrate, curling sometimes occurs at the width direction end of the substrate during the drying stage of the coating liquid film formed on the first surface. In addition, the curling generated at this stage sometimes makes it difficult to form the desired coating liquid film on the second surface. For example, when curling occurs at the above stage, it is sometimes impossible to reduce the offset amount of the width of the coating liquid film formed on the first surface and the width of the coating liquid film formed on the second surface. As a result, curling sometimes also occurs in the obtained laminate (specifically, a laminate having a dried film).

[0040] Therefore, the inventors of the present invention have discovered that, in the case of double-sided coating as described above, even if curling occurs at the widthwise end of the substrate on which the coating liquid film is formed on the first surface, the curling is corrected while the solid content concentration of the coating liquid film formed on the first surface is within a certain range and the coating liquid is applied to the second surface, thereby reducing the amount of misalignment between the width of the coating liquid film formed on the first surface and the width of the coating liquid film formed on the second surface, and obtaining a laminate with reduced curling.

[0041] A method for manufacturing a laminated body according to the present embodiment comprises the following steps: for a substrate being continuously transported on a transport path, a first coating liquid is initially applied to a first surface of the substrate, and while the solid content concentration of the first coating liquid film formed by the first coating liquid is between 40% by mass and 80% by mass, a second coating liquid is initially applied to a second surface opposite to the first surface of the substrate, and in an area where the substrate is transported along a curved transport path by applying pressure to the first surface side by gas, the second coating liquid is applied to the second surface, and the misalignment amount between the width of the first coating liquid film on the first surface and the width of the second coating liquid film formed by the second coating liquid on the second surface is within 1 mm.

[0042] According to the method for producing a laminated body according to the present embodiment, it is possible to obtain a laminated body in which a film formed on the first surface side of a substrate, a substrate, and a film formed on the second surface side of the substrate are arranged in this order.

[0043] According to the manufacturing method of the laminated body involved in the present embodiment, the second coating liquid is applied to the second surface opposite to the first surface of the substrate when the solid content concentration of the first coating liquid film formed by the first coating liquid is between 40 mass % and 80 mass %. By setting the solid content concentration of the first coating liquid film formed by the first coating liquid when the second coating liquid is applied to the second surface to be less than 80 mass %, the substrate having the first coating liquid film in a state where a certain degree of solvent remains is conveyed along a curved conveying path, so that if curling occurs at the end in the width direction, the curling can be corrected. Therefore, since the substrate having the first coating liquid film is conveyed along a curved conveying path, the curling is corrected and is in a state that does not damage the planarity of the substrate, the second coating liquid can be applied to the desired area of ​​the second surface. As a result, the misalignment amount (i.e., within 1 mm) between the width of the coating liquid film formed on the first surface and the width of the coating liquid film formed on the second surface can be reduced.

[0044] Then, by setting the offset amount to within 1 mm, the force that will curl toward the first surface due to the shrinkage caused by the drying of the first coating liquid film and the force that will curl toward the second surface due to the shrinkage caused by the drying of the second coating liquid film can be balanced and well offset with the substrate as the center. As a result, in the laminated body formed by drying the substrate on which the first coating liquid film and the second coating liquid film are formed, the curling generated at the width direction end of the substrate can be reduced.

[0045] Furthermore, by setting the solid content concentration of the first coating liquid film formed by the first coating liquid at the time of starting to apply the second coating liquid to the second surface to be 40% by mass or more, the shape retention of the first coating liquid film is improved, and even if the pressure generated by the gas is applied to the first surface side, the surface shape of the first coating liquid film can be suppressed from being rough. Thus, a film with excellent surface shape is formed on the first surface.

[0046] On the other hand, in the method described in Japanese Patent Gazette No. 2004-344693, it is presumed that the coating liquid film formed on the first surface of the substrate begins to be coated on the second surface of the substrate after drying, so that the solid content concentration of the coating liquid film formed on the first surface at the stage of starting to coat the second surface is 100% by mass or a value close thereto.

[0047] In addition, in the method described in Japanese Patent Application Laid-Open No. 2-119968, after the coating liquid film formed on the first surface of the substrate is gelled, coating on the second surface of the substrate is started. This method is a special example of using a gelled coating liquid film, and it is speculated that during the gelling process of the coating liquid film, the solid content concentration of the coating liquid film formed on the first surface changes to a low state (for example, less than 40% by mass). In addition, it is believed that in this method, the gelling process tends to be very long, and the misalignment amount between the width of the coating liquid film on the first surface and the width of the coating liquid film on the second surface becomes large.

[0048] Hereinafter, each step of the method for producing the laminated body according to the present embodiment will be described.

[0049] First, regarding an example of a method for producing a laminate, refer to Figure 1 Here, Figure 1 It is a schematic diagram of an apparatus to which a method for producing a laminated body according to one embodiment is applied, and is used to explain each step.

[0050] like Figure 1 As shown, the belt-shaped substrate 10 wound into a roll shape starts to be conveyed by sending out its front end in the direction of the arrow, and is continuously conveyed until it is wound into a roll shape. Figure 1 The substrate 10 shown is continuously transported by the support roller 20 and the floating transport mechanism 40 and other transport mechanisms not shown. Figure 1 In the figure, the “line” denoted by the reference numeral 10 also becomes the moving path of the substrate 10, that is, the “transport path”.

[0051] like Figure 1 As shown, in the area where the substrate 10 is wound around the support roller 20, the first coating liquid is applied to the first surface of the substrate 10 by the coating mechanism 30 (hereinafter also referred to as step A). ​​By step A, a first coating liquid film formed by the first coating liquid (not shown) is formed on the first surface of the strip-shaped substrate 10.

[0052] Next, the strip-shaped substrate 10 having the first coating liquid film (not shown) formed on the first surface is bent along the outer peripheral surface of the roller-shaped floating conveying mechanism 40 and conveyed in a state not in contact with the surface of the first surface side (i.e., in a state not in contact with the first coating liquid film). Here, the substrate 10 is conveyed along the curved conveying path by the floating conveying mechanism 40 by applying pressure to the first surface side by gas. Then, in the area where the strip-shaped substrate 10 is conveyed in a curved state by the floating conveying mechanism 40, the second coating liquid is applied to the second surface of the substrate 10 by the coating mechanism 50 (hereinafter also referred to as step B). By step B, a second coating liquid film (not shown) made of the second coating liquid is formed on the second surface of the strip-shaped substrate 10.

[0053] Next, after the second coating liquid film is formed on the second surface, the strip-shaped substrate 10 passes through a drying mechanism 60 (hereinafter, also referred to as step C). The first coating liquid film on the first surface and the second coating liquid film on the second surface of the strip-shaped substrate 10 are dried by step C, and films are formed on both surfaces of the substrate 10.

[0054] Then, the base material 10 having passed through the drying mechanism 60 is wound into a roll shape after going through an arbitrary step (not shown) as necessary.

[0055] [Step A]

[0056] In step A, the first coating liquid is initially applied to the first surface of the substrate which is continuously conveyed.

[0057] The substrate used in this step is not particularly limited as long as it can be continuously transported, and a substrate may be selected in accordance with the application of the laminate to be formed.

[0058] The substrate may be made of resin or metal, and may have a multilayer structure including a resin layer and a metal layer.

[0059] Furthermore, as the substrate, for example, a substrate having a thermal conductivity of 200 W / m·K or more can be used. For example, as the substrate having a thermal conductivity of 200 W / m·K or more, in the case of a substrate having a multilayer structure including a metal layer and a resin layer, the thermal conductivity of the substrate as a whole only needs to be 200 W / m·K or more.

[0060] The upper limit of the thermal conductivity of the substrate is not particularly limited, and is, for example, 500 W / m·K.

[0061] Specific examples of the substrate having the above-mentioned thermal conductivity include copper, aluminum, silver, gold, and metal substrates based on alloys thereof.

[0062] Among them, from the viewpoints of shape stability as a substrate, practical use, and the like, a copper substrate and an aluminum substrate are preferably used.

[0063] The thermal conductivity of the substrate was measured in the following manner.

[0064] First, the substrate is cut into a size suitable for the device described later to obtain a sample for measurement. For the obtained sample for measurement, the thermal diffusion coefficient in the thickness direction is measured by the laser flash method. Next, the specific gravity of the sample for measurement is measured by a balance using a specific gravity measurement kit. In addition, the specific heat of the sample for measurement at 25°C is used to obtain the thermal conductivity of the sample for measurement (i.e., the substrate) by multiplying the obtained thermal diffusion coefficient by the specific gravity and specific heat.

[0065] Here, when measuring the thermal diffusion coefficient, for example, "LFA467" of NETZSCH is used. When measuring the specific gravity, for example, a balance "XS204" of Mettler-Toledo International Inc. using a solid specific gravity measurement kit is used. When measuring the specific heat, for example, "DSC320 / 6200" of Seiko Instruments Inc. is used.

[0066] From the viewpoint of suitability for a roll-to-roll method, the thickness of the substrate may be appropriately set.

[0067] The thickness of the substrate is, for example, preferably 5 μm to 100 μm, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 30 μm.

[0068] Even when the thickness of the substrate is thin as described above, the method for producing a laminated body according to the present embodiment can reduce curling.

[0069] From the viewpoint of suitability for a roll-to-roll method and from the perspective of the desired film width and length, the width and length of the substrate may be appropriately set.

[0070] The thickness of the substrate is measured in the following manner.

[0071] Specifically, the thickness of the substrate was measured at three locations in the width direction (specifically, 5 mm from both edges in the width direction and the center in the width direction) at intervals of 500 mm in the longitudinal direction using a contact thickness gauge.

[0072] The arithmetic mean of the 9 measured values ​​was calculated and used as the thickness of the substrate.

[0073] As the contact-type thickness measuring machine, for example, S-2270 from Fujiwork Co., Ltd. is used.

[0074] -First coating liquid-

[0075] The first coating liquid used in this step is not particularly limited as long as it is a liquid containing a solvent (or a dispersion medium) and has fluidity and can form a target film.

[0076] The first coating liquid may use an organic solvent or water as a solvent (or dispersion medium).

[0077] As the first coating liquid, for example, it can be an aqueous coating liquid in which the solvent (or dispersion medium) contained in the coating liquid is substantially water. "The solvent (or dispersion medium) is substantially water" means that when preparing the coating liquid, it is allowed to contain solvents other than water introduced when using solid components. Specifically, "the solvent (or dispersion medium) is substantially water" means that the proportion of water in all solvents (or all dispersion media) is 90% by mass or more, and the proportion of water in all solvents (or all dispersion media) is preferably 95% by mass or more, and it is particularly preferred that all solvents (or all dispersion media) are water.

[0078] Furthermore, the solid content refers to components other than the solvent (or dispersion medium).

[0079] The aqueous coating liquid is not particularly limited as long as it is a liquid containing water as a solvent (or dispersion medium) and a solid component.

[0080] The solid content contained in the water-based coating liquid includes, in addition to components for obtaining the target film, components for improving coating suitability and the like.

[0081] Examples of water contained in the aqueous coating liquid include natural water, purified water, distilled water, ion exchanged water, pure water, ultrapure water (e.g., Milli-Q water), etc. In addition, Milli-Q water refers to ultrapure water obtained by a Milli-Q water production device of Merck KGaA.

[0082] The content of water in the aqueous coating liquid is not particularly limited, but is, for example, preferably 40% by mass or more, and more preferably 50% by mass or more, relative to the total mass of the aqueous coating liquid.

[0083] The upper limit of the water content may be less than 100% by mass, and is, for example, 90% by mass with respect to the total mass of the aqueous coating liquid from the viewpoint of coating suitability.

[0084] The water-based coating liquid may contain particles as one of the solid components. That is, the water-based coating liquid may be a coating liquid containing particles.

[0085] When an aqueous coating liquid containing particles is used, the particles also aggregate during the drying stage, which tends to easily cause curling of the widthwise end of the substrate. In the method for manufacturing a laminated body according to the present embodiment, even when an aqueous coating liquid containing particles is used as the first coating liquid, curling of the widthwise end of the substrate can be reduced.

[0086] The particles are not particularly limited as long as they are particulate materials, and may be inorganic particles, organic particles, or composite particles of inorganic and organic materials.

[0087] As the inorganic particles, known inorganic particles that can be suitably used in the target film can be used.

[0088] Examples of inorganic particles include particles of metals (alkali metals, alkaline earth metals, transition metals, alloys of these metals, etc.), particles of semimetals (silicon, etc.), particles of compounds containing metals or semimetals (oxides, hydroxides, nitrides, etc.), inorganic pigments containing carbon black, etc., and the like.

[0089] Inorganic particles include particles of minerals such as mica.

[0090] As the organic particles, known organic particles that can be suitably used in the target film can be used.

[0091] The organic particles are not particularly limited as long as they are particles of solid organic matter such as resin particles and organic pigment particles.

[0092] Examples of composite particles of an inorganic substance and an organic substance include composite particles in which inorganic particles are dispersed in a matrix of an organic substance, composite particles in which organic particles are coated with an inorganic substance, and composite particles in which inorganic particles are coated with an organic substance.

[0093] The particles may be surface treated for the purpose of imparting dispersibility or the like.

[0094] In addition, the particles may be subjected to surface treatment to form the above-mentioned composite particles.

[0095] The particle size, shape, specific gravity, and usage (for example, whether to use in combination) of the particles are not particularly limited and may be appropriately selected according to the target film or conditions suitable for film production.

[0096] The content of the particles in the water-based coating liquid is not particularly limited and may be appropriately determined depending on the target film, conditions suitable for producing the film, or the purpose of adding the particles.

[0097] The solid content contained in the water-based coating liquid is not particularly limited, and various components used to obtain a target film may be mentioned.

[0098] Specifically, the solid components contained in the aqueous coating liquid include, in addition to the above-mentioned particles, binder components, components that contribute to the dispersibility of the particles, polymerizable compounds, reactive components such as polymerization initiators, components for improving coating performance such as surfactants, and other additives.

[0099] -Thickness of the first coating liquid film-

[0100] The thickness of the first coating liquid film formed in this step is not particularly limited and may be appropriately determined depending on the target film.

[0101] The thickness of the first coating liquid film is, for example, preferably 40 μm or more, more preferably 40 μm to 200 μm, and further preferably 40 μm to 100 μm.

[0102] The thicker the first coating liquid film becomes, the more likely it is that curling will occur at the width direction end of the substrate during the drying stage of the first coating liquid film. In the method for manufacturing the laminated body according to the present embodiment, curling at the width direction end of the substrate can be reduced even when the first coating liquid film becomes thicker.

[0103] The thickness of the coating liquid film was measured in the following manner.

[0104] Specifically, the first coating film was measured at three locations along the width direction (specifically, 5 mm from both edges in the width direction and the center in the width direction) using an optical interference thickness meter. The arithmetic mean of the measured values ​​at the three points was calculated and used as the coating film thickness.

[0105] As the optical interference type thickness measuring instrument, for example, an infrared spectroscopic interference type film thickness meter SI-T80 manufactured by KEYENCE CORPORATION is used.

[0106] -Width of coating film-

[0107] The width of the first coating liquid film in this step (ie, coating width) is not particularly limited and may be determined according to the width of the substrate, the application of the film, and the like.

[0108] The width of the first coating liquid film can be selected to be, for example, 100 mm or more, or 1000 mm or more.

[0109] The upper limit of the width of the first coating liquid film is the width of the substrate.

[0110] -Width of non-coated area-

[0111] When the first coating liquid film is formed on the first surface of the substrate, from the viewpoint of facilitating the effect of the method for manufacturing the laminate involved in the present embodiment, the width of the non-coated area at both ends in the width direction of the substrate (i.e., the width of the exposed portion of the substrate) is, for example, preferably greater than 2 mm, and more preferably greater than 5 mm.

[0112] The upper limit of the width of the non-coated region on the first surface is preferably 30 mm, for example.

[0113] The width of the coating liquid film is measured in the following manner.

[0114] That is, the upper surface of the coating liquid film was observed from the film surface side, and the width of the coating liquid film was measured at three points at intervals of 500 mm in the longitudinal direction using a ruler.

[0115] The arithmetic mean of the values ​​measured at the three points was calculated and used as the width of the coating liquid film.

[0116] Then, the width of the coated area was measured as follows.

[0117] That is, the top surface is observed from the film surface side of the coating film, and the shortest distance from the end of the width direction of the substrate to the end of the coating film is measured at three points with an interval of 500 mm in the length direction using a ruler. The measurement is performed at both ends of the width direction of the substrate.

[0118] The arithmetic mean of the measured values ​​at the six points was calculated and used as the width of the coated area.

[0119] - Application of the first coating liquid -

[0120] A known coating mechanism is applied to the coating of the first coating liquid in this step.

[0121] As a coating mechanism (e.g. Figure 1 The coating mechanism 30) in the method may specifically include coating devices utilizing curtain coating, dip coating, printing coating, spray coating, slit coating, roller coating, slide coating, blade coating, gravure coating, wire rod coating, and the like.

[0122] Among them, as the coating mechanism in this step, from the viewpoint of achieving high-definition coating, it is preferable to use a coating device using a slit coating method, more specifically, an extrusion type coating die.

[0123] -Support Roller-

[0124] In this step, when applying the first coating liquid, the substrate can be conveyed in a stretched state. From the viewpoint of improving the coating accuracy, Figure 1 As shown, this is preferably carried out in the region where the substrate is wound around the support roller.

[0125] The support roller is a rotatable member. When the support roller rotates, the base material can be conveyed in a state of being stretched along the outer peripheral surface of the support roller.

[0126] From the viewpoint of controlling the drying process of the coating liquid film and suppressing blushing of the coating film due to a decrease in the film surface temperature of the coating liquid film (ie, whitening of the coating film due to the generation of fine condensation), the backup roll may be heated.

[0127] The surface temperature of the backup roller is preferably controlled by a temperature control mechanism. The surface temperature of the backup roller is more preferably controlled by a temperature control mechanism based on the detected surface temperature.

[0128] As the temperature control mechanism, for example, a heating mechanism and a cooling mechanism can be cited. In the heating mechanism, for example, induction heating, water heating or oil heating can be used. In the cooling mechanism, for example, cooling by cooling water is used.

[0129] The diameter of the backup roll is preferably 100 to 1,000 mm, more preferably 100 to 800 mm, and particularly preferably 200 to 700 mm, from the viewpoint of easy winding of the substrate, easy coating with a die, and the production cost of the backup roll.

[0130] From the viewpoint of productivity and coating properties, the conveyance speed of the substrate by the backup roll is preferably, for example, 10 m / min to 100 m / min.

[0131] From the viewpoint of stabilizing the substrate conveyance when applying the first coating liquid and suppressing the occurrence of uneven thickness of the coating liquid film, the wrap angle of the substrate relative to the support roller is preferably 60° or more, more preferably 90° or more. In addition, the upper limit of the wrap angle can be set to 180°, for example. The wrap angle refers to the angle formed by the conveyance direction of the substrate when the substrate is in contact with the support roller and the conveyance direction of the substrate when the substrate is separated from the support roller.

[0132] [Step B]

[0133] In step B, while the solid content concentration of the first coating liquid film formed from the first coating liquid is 40 mass % to 80 mass %, the second coating liquid is started to be applied to the second surface opposite to the first surface of the substrate.

[0134] Then, in this step, in a region where the substrate is conveyed along the curved conveyance path by applying pressure to the first surface side by gas, coating of the second coating liquid onto the second surface is started.

[0135] -Solid content concentration of the first coating liquid film-

[0136] The timing for starting to apply the second coating liquid to the second surface of the substrate is such that the solid content concentration of the first coating liquid film is between 40% by mass and 80% by mass.

[0137] The timing for starting to apply the second coating liquid to the second surface of the substrate is preferably such that the solid content concentration of the first coating liquid film is between 45% by mass and 75% by mass, and more preferably between 50% by mass and 65% by mass.

[0138] When the solid content concentration of the first coating liquid film is less than 40% by mass, due to the low solid content concentration of the first coating liquid surface, when the gas is applied to the first surface side, the first coating liquid film flows and the plane shape is rough, or the thickness of the first coating liquid film is uneven. On the other hand, when the solid content concentration of the first coating liquid film exceeds 80%, when the substrate is transported along a curved transport path, the first coating liquid film cannot follow the shape change of the substrate, and cracks are sometimes generated in the first coating liquid film.

[0139] The solid content concentration of the coating liquid film can be determined by measuring the optical thickness from the time of coating until the film becomes dry using an optical interference type thickness measuring instrument (for example, infrared spectral interference type film thickness meter SI-T80 manufactured by KEYENCE CORPORATION).

[0140] Specifically, first, the optical thickness from the time of coating to the time of becoming a dry film is measured. Next, the thickness of the dried film (dry film) is measured using a contact thickness gauge. The thickness of the measured dry film is divided by the optical thickness, and the thickness of the wet film (coating film) is calculated from the optical thickness. Then, the amount of solvent (or dispersion medium) at the measurement point is obtained. The mass of the solvent (or dispersion medium) is calculated from the amount of solvent (or dispersion medium) obtained, and the value of the solid content concentration at the measurement point is calculated.

[0141] The timing for starting to apply the second coating liquid to the second surface of the substrate may be determined based on the position on the conveyance path where the solid content concentration of the first coating liquid film formed on the first surface falls within the above range.

[0142] Specifically, by the above method, the change of the solid content concentration of the coating liquid film is investigated in advance, and the position of the solid content concentration of the first coating liquid film formed on the first surface on the conveying path within the above range is determined. Then, the coating mechanism 50 is set to the position on the determined conveying path, and the second coating liquid is started to be applied to the second surface.

[0143] In addition, the installation position of the coating mechanism 50 is fixed, and the solid content concentration of the first coating liquid film can be controlled at the location where the second coating liquid is applied from the coating mechanism 50, so that the solid content concentration of the first coating liquid film formed on the first surface becomes the above range. In this case, the solid content concentration of the first coating liquid used in step A can be adjusted. In addition, the first coating liquid film can be pre-dried and the solid content concentration of the first coating liquid film formed on the first surface can be adjusted during the period from the start of applying the first coating liquid to the first surface to the start of applying the second coating liquid to the second surface.

[0144] -Floating conveying mechanism-

[0145] In this step, the substrate is conveyed along a curved conveying path by applying pressure to the first surface side of the substrate (the film surface of the first coating liquid film) by gas. In order to form such a curved conveying path, a floating conveying mechanism is used, which uses a roller member having a gas ejecting mechanism capable of ejecting gas from an ejection port on the outer peripheral surface.

[0146] When the roller member having the gas ejecting mechanism is used and gas is ejected from the ejection ports on the outer peripheral surface of the roller member to apply pressure to the first surface side of the substrate, the substrate floats from the outer peripheral surface of the roller member and is conveyed while being bent along the outer peripheral surface.

[0147] The floating conveying mechanism is not limited to the roller member as long as it can form the curved conveying path, and may be, for example, a member having an arc-shaped outer peripheral surface when viewed from the side and having a gas ejection mechanism capable of ejecting gas from an ejection port on the outer peripheral surface.

[0148] Since the substrate bent and conveyed by the floating conveying mechanism is stretched in a shape bent in the conveying direction, when the second coating liquid starts to be applied to the second surface, even if curling occurs at the width direction end of the substrate, the curling can be restricted.

[0149] More specifically, if Figure 1 As shown in FIG. 1 , in the area where the substrate 10 (and the conveying path) is bent and conveyed (specifically, from Figure 1 In the region from position P1 to position P2), even if curling occurs at the width direction end of the substrate 10 where the first coating liquid film is formed in the previous region, the curling limiting force acts in the region from position P1 to position P2, thereby limiting the curling.

[0150] And, if Figure 1 As shown in FIG. 1 , in the area where the substrate 10 (and the conveying path) is bent and conveyed (specifically, from Figure 1 In the region from position P1 to position P2), the substrate 10 can be conveyed in a stretched state, so that the conveyance of the substrate 10 is stabilized, and thus the coating accuracy of the second coating liquid by the coating mechanism 50 is also improved.

[0151] In this step, from the viewpoint of more strongly restricting curling, the curved conveying path (specifically, for example, Figure 1 The radius of curvature of the region from position P1 to position P2 is preferably 100 mm to 500 mm, more preferably 200 mm to 400 mm, and further preferably 250 mm to 350 mm.

[0152] The curvature radius of the curved conveying path may be adjusted by adjusting the curvature radius of the outer peripheral surface of the floating conveying mechanism having a circular or arc-shaped outer peripheral surface when viewed from the side.

[0153] In general, from the viewpoint of stabilizing the conveyance of the substrate, the floating amount of the substrate of the floating conveying mechanism having a circular or arc-shaped outer peripheral surface when viewed from the side is set to be constant. Therefore, the value obtained by adding the floating amount to the radius of curvature of the floating conveying mechanism having a circular or arc-shaped outer peripheral surface when viewed from the side (i.e., the radius of curvature of the circular or arc-shaped outer peripheral surface) is equivalent to the radius of curvature of the curved conveying path.

[0154] However, as described later, since the maximum floating amount is 500 μm, the curvature radius of the floating conveying mechanism having a circular or arc-shaped outer peripheral surface when viewed from the side (i.e., the curvature radius of the circular or arc-shaped outer peripheral surface) can be replaced by the curvature radius of the curved conveying path.

[0155] In this step, from the viewpoint of more strongly restricting curling, the curved conveying path (specifically, for example, Figure 1 The distance (the distance from position P1 to position P2) is preferably 350 mm to 1750 mm, more preferably 600 mm to 1500 mm, and further preferably 800 mm to 1200 mm.

[0156] The distance of the curved conveying path may be adjusted by adjusting the length of the substrate in the conveying direction or the wrap angle of the substrate along the outer peripheral surface of the floating conveying mechanism having a circular or arcuate outer peripheral surface when viewed from the side.

[0157] In this step, from the viewpoint of more strongly restricting the curling and improving the coating accuracy of the second coating liquid, the distance from the bending start point of the curved conveying path to the coating start point of the second coating liquid (specifically, for example, from Figure 1 The distance from position P1 to position P3) is preferably the distance of the curved conveying path (specifically, for example, from Figure 1 The distance from the curved starting point of the curved conveying path to the application start point of the second coating liquid is preferably 50±20% of the distance of the curved conveying path, and the distance from the curved starting point of the curved conveying path to the application start point of the second coating liquid is further preferably 50±10% of the distance of the curved conveying path.

[0158] That is, it is preferred that the second coating liquid be applied to the second surface starting near the center of the curved conveyance path.

[0159] In order to satisfy the above conditions, it is only necessary to adjust the installation position of the coating mechanism 50 .

[0160] Here, Figure 1 The positions P1, P2, and P3 in FIG.

[0161] Figure 1 The position P1 in FIG. 1 is the starting point of the curved conveying path and is the point where the gas ejected from the floating conveying mechanism 40 starts to be supplied to the first surface side of the conveyed substrate 10 , which corresponds to the inflection point of the conveying path.

[0162] Figure 1 The position P2 in FIG. 1 is the bending end point of the curved conveying path and is the point where the gas ejected from the floating conveying mechanism 40 to the first surface side of the conveyed substrate 10 ends, which corresponds to the inflection point of the conveying path.

[0163] Figure 1 The position P3 in FIG. 1 is a position where the second coating liquid starts to be applied to the second surface of the conveyed substrate 10 , and is a position facing the coating mechanism 50 .

[0164] The distance from position P1 to position P3 and the distance from position P1 to position P2 can be obtained, for example, from the positions corresponding to position P1, position P2 and position P3 in the mechanical drawing (i.e., design drawing) of the device being used and the ratio of the mechanical drawing.

[0165] At this time, the position P1 and the position P2 are set as contact points between the floating transport mechanism 40 and the transport path of the substrate 10 .

[0166] In this step, from the viewpoint of more strongly restricting curling and improving the coating accuracy of the second coating liquid, the wrap angle of the substrate relative to the floating conveying mechanism is preferably 60° or more, preferably 90° or more, and more preferably 120° or more. The upper limit of the wrap angle can be set to 210°, for example. The wrap angle refers to the angle formed by the conveying direction of the substrate at the starting point of the bend when the substrate is bent by the floating conveying mechanism and the conveying direction of the substrate at the end point of the bend.

[0167] The floating amount of the substrate relative to the floating conveying mechanism used in this step is preferably 500 μm or less, and more preferably 300 μm or less, from the viewpoint of stabilizing the conveying of the substrate. The lower limit of the floating amount of the substrate can be determined based on the thickness of the first coating liquid film, and can be, for example, the thickness of the first coating liquid film + 50 μm, and preferably the thickness of the first coating liquid film + 100 μm.

[0168] The floating amount of the substrate with respect to the floating transport mechanism refers to the shortest distance between the substrate in a state where the first coating liquid film is not formed and the outer peripheral surface of the floating transport mechanism.

[0169] Here, the floating amount can be measured using a laser displacement meter.

[0170] As the floating conveying mechanism used in this step, the support roller (support body) 11 described in Japanese Patent Application Laid-Open No. 2001-310148 and the non-contact conveying device described in Japanese Patent Application Laid-Open No. 2004-256264 (for example, see Figure 2 ), the sheet support device described in Japanese Patent Publication No. 2020-050455 (for example, refer to FIG6 ), the conveying device described in Japanese Patent Publication No. 2020-152570 (for example, refer to FIG9 ), etc. In addition, the various conditions related to the floating conveyance of the substrate described in these publications can also be applied to the method for manufacturing the laminated body involved in the present embodiment within the range that does not impair the effect exerted by the method for manufacturing the laminated body involved in the present embodiment.

[0171] -Second coating liquid-

[0172] The second coating liquid used in this step is not particularly limited as long as it is a liquid containing a solvent (or dispersion medium) and having fluidity like the first coating liquid and can form a target film.

[0173] The second coating liquid may be the same coating liquid as the first coating liquid (for example, the aqueous coating liquid exemplified in the first coating liquid), or may be a coating liquid different from the first coating liquid.

[0174] From the viewpoint of effectively suppressing curling of the width direction end portion of the substrate generated during the drying process of the first coating liquid film formed on the first surface, the second coating liquid is preferably the same coating liquid as the first coating liquid (for example, the aqueous coating liquid exemplified in the first coating liquid).

[0175] -Thickness of the second coating liquid film-

[0176] The thickness of the second coating liquid film formed in this step is not particularly limited and may be appropriately determined depending on the target film.

[0177] The thickness of the second coating liquid film is, for example, preferably 40 μm or more, more preferably 40 μm to 200 μm, and further preferably 40 μm to 100 μm.

[0178] The more the thickness of the second coating liquid film is the same as that of the first coating liquid film, the easier it is to reduce the curling of the width direction end of the substrate. Therefore, it is preferred that the thickness difference between the first coating liquid film and the second coating liquid film is small, for example, preferably 10 μm or less, more preferably 5 μm or less, and further preferably 0.

[0179] -Width of coating film and width of non-coating area-

[0180] From the viewpoint of satisfying the range of the displacement amount described later, the width of the second coating liquid film (ie, coating width) in this step is preferably equal to the width of the first coating liquid film.

[0181] Furthermore, from the perspective of satisfying the range of the offset amount described later, it is preferred that the width of the non-coated area when forming the second coating liquid film on the second surface of the substrate (i.e., the width of the exposed portion of the substrate) is equal to the width of the non-coated area on the first surface side.

[0182] - Application of the second coating liquid -

[0183] The second coating liquid in this step is applied using a known coating mechanism.

[0184] As a coating mechanism (e.g. Figure 1 The coating mechanism 50) may be any of various coating devices similar to those used when coating the first coating liquid.

[0185] Among them, as the coating mechanism in this step, from the viewpoint of achieving high-definition coating, it is preferable to use a coating device using a slit coating method, more specifically, an extrusion type coating die.

[0186] -Amount of misalignment-

[0187] In the method for manufacturing a laminated body according to the present embodiment, the misalignment between the width of the first coating liquid film on the first surface and the width of the second coating liquid film formed by the second coating liquid on the second surface is set to within 1 mm. From the viewpoint of effectively suppressing the curling of the width direction end of the substrate generated during the drying process of the first coating liquid film formed on the first surface, the misalignment is more preferably within 0.5 mm.

[0188] As described above, when the amount of misalignment is small, the coating liquid film is formed in substantially the same range on both sides of the substrate. In this way, curling of the width direction end of the substrate can be suppressed.

[0189] That is, when the amount of displacement is larger than 1 mm, curling of the width direction end portion of the substrate may not be suppressed.

[0190] The amount of displacement can be determined by the same method as the measurement of the width of the non-coated region described above.

[0191] The above-mentioned offset amount can be controlled by adjusting the positions in the width direction of the coating mechanism for coating the first coating liquid on the first surface and the coating mechanism for coating the second coating liquid on the second surface. In addition, the above-mentioned offset amount can be controlled by adjusting the alignment of the roller member in contact with the substrate and changing the position in the width direction of the substrate between coating the first coating liquid on the first surface and coating the second coating liquid on the second surface.

[0192] [Step C]

[0193] In step C, the substrate on which the first coating liquid film and the second coating liquid film are formed is dried. That is, in this step, the first coating liquid film and the second coating liquid film are dried.

[0194] -dry-

[0195] In this step, when drying the coating liquid film, a known drying mechanism is applied.

[0196] As a drying mechanism (e.g. Figure 1 The drying mechanism 60) includes, specifically, an oven, a hot air blower, an infrared (IR) heater, and the like.

[0197] The drying conditions in this step may be appropriately determined according to the material of the substrate, the type of the coating liquid film, and the like.

[0198] In the above-described manner, a laminated body was obtained in which films were formed on both surfaces of the substrate and the films, the substrate, and the films were arranged in this order.

[0199] The thickness of the film obtained in step C is not particularly limited as long as it is a thickness corresponding to the purpose, application, etc.

[0200] In the method for producing a laminate according to the present embodiment, the thickness of each of the films formed on both surfaces of the substrate is preferably 40 μm or more, more preferably 50 μm or more, and further preferably 60 μm or more.

[0201] The upper limit of the thickness of the film formed on both surfaces of the substrate is not particularly limited and may be determined according to the intended use, and is, for example, 300 μm.

[0202] The thickness of the film obtained in step C is measured in the same manner as the thickness of the coating liquid film.

[0203] [Other processes]

[0204] In at least one of the steps before step A and after step C, other steps may be included as necessary.

[0205] The other steps are not particularly limited, and examples thereof include a pretreatment step before forming the coating liquid film, a post-treatment step for the film or laminate formed on the first and second surfaces, and the like, depending on the application of the laminate.

[0206] Specific examples of the other steps include a step of surface treating the substrate, a step of curing the formed film, a step of compressing the laminated body, and a step of cutting the laminated body.

[0207] Since the method for producing a laminated body according to the present embodiment is a method for forming films on both surfaces of a substrate that is continuously conveyed, it is suitable for producing a laminated body for applications requiring high productivity.

[0208] Example

[0209] Hereinafter, the present invention will be described in more detail by giving examples. The materials, usage amounts, ratios, details of each process, etc. shown in the following examples can be appropriately changed without departing from the purpose of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0210] In addition, “portions” are based on mass.

[0211] <Preparation of base material>

[0212] An aluminum substrate 1 (thermal conductivity: 230 W / m·K) (abbreviated as AL1) having a width of 220 mm, a thickness of 15 μm, and a length of 300 m was prepared.

[0213] An aluminum substrate 2 (thermal conductivity: 230 W / m·K) (abbreviated as AL2) having a width of 220 mm, a thickness of 40 μm, and a length of 300 m was prepared.

[0214] A PET (polyethylene terephthalate) substrate 1 (thermal conductivity: 0.23 W / m·K) (abbreviated as P1) having a width of 220 mm, a thickness of 75 μm, and a length of 300 m was prepared.

[0215] <Preparation of water-based coating liquid>

[0216] [Preparation of water-based coating liquid A]

[0217] The following components were mixed to prepare a water-based coating liquid A.

[0218] Polyvinyl alcohol: 58 parts

[0219] (CKS-50: saponification degree 99 mol%, polymerization degree 300, Nippon Synthetic Chemical Industry Co., Ltd.)

[0220] ·DKS Co.Ltd.CELLOGEN PR: 24 copies

[0221] Surfactant (NIHON EMULSION Co., Ltd., EMALEX 710): 5 parts

[0222] · Water dispersion of Artpearl (registered trademark) J-7P prepared by the following method: 913 parts

[0223] (Water dispersion of Artpearl J-7P)

[0224] 3 parts of EMALEX 710 (NIHON EMULSION Co., Ltd., nonionic surfactant) and 3 parts of sodium carboxymethylcellulose were added and dissolved in 49 parts of pure water. 20 parts of Artpearl J-7P (Negami Chemical Industrial Co., Ltd., silica composite cross-linked acrylic resin microparticles) were added to the obtained aqueous solution, and dispersed for 15 minutes at 10,000 rpm (revolutions per minute; hereinafter, the same). Artpearl J-7P water dispersion (particle concentration: 20 mass%) was obtained.

[0225] The silica-composite cross-linked acrylic resin fine particles in the obtained water dispersion had a true specific gravity of 1.20 and an average particle size of 6.5 μm.

[0226] [Preparation of water-based coating liquid B]

[0227] The following components were mixed and stirred using a dissolver (2000 rpm, 30 minutes) to prepare a water-based coating liquid B (dispersion A:dispersion B=25:75). The viscosity of the water-based coating liquid B was 20 mPa·s, and the average particle size of the particles was 0.108 μm.

[0228] Dispersion A prepared by the following method: 132.1 parts

[0229] Dispersion B prepared by the following method: 396.2 parts

[0230] Boric acid (crosslinking agent): 2.94 parts

[0231] Polyvinyl alcohol (7.3 mass % aqueous solution): 230.7 parts

[0232] (Kuraray Co., Ltd., PVA 235, saponification degree 88%, polymerization degree 3500)

[0233] ·Diethylene glycol monobutyl ether: 2.7 parts

[0234] (Butysenol 20-P, KH NEOCHEM CO.,LTD.)

[0235] Ion exchange water: 93.5 parts

[0236] Polyoxyethylene lauryl ether (surfactant): 0.49 parts

[0237] (10 mass % aqueous solution of EMULGEN 109P, HLB value 13.6, Kao Corporation)

[0238] Ethanol: 41.4 parts

[0239] (Preparation of Dispersion Liquid A)

[0240] After mixing the following components and dispersing them by ultrasonic wave, the dispersion liquid was heated to 30° C. and maintained for 8 hours to prepare a dispersion A.

[0241] Fumed silica particles (inorganic particles): 299.6 parts

[0242] (AEROSIL 300SF75, NIPPON AEROSIL CO.,LTD.)

[0243] Ion exchange water: 900 parts

[0244] Alphain 83 (40.0 mass % aqueous solution): 300 parts

[0245] (Dispersant, TAIMEI CHEMICALS Co., Ltd.)

[0246] (Preparation of Dispersion Liquid B)

[0247] After mixing the following components and dispersing them by ultrasonic wave, the dispersion liquid was heated to 30° C. and maintained for 8 hours to prepare a dispersion B.

[0248] Fumed silica particles (inorganic particles): 225.2 parts

[0249] (AEROSIL 300SF75, NIPPON AEROSIL CO.,LTD.)

[0250] Ion exchange water: 600 parts

[0251] Cationic polymer A of the following structure (25 mass % aqueous solution): 90 parts

[0252] [Chemical formula 1]

[0253]

[0254] [Example 1]

[0255] Through Figure 1The apparatus constructed as shown in the figure starts to apply the water-based coating liquid A (first coating liquid) to the first surface of the continuously conveyed aluminum substrate (AL1), and then starts to apply the water-based coating liquid A (second coating liquid) to the second surface when the solid content concentration of the coating liquid film formed by the water-based coating liquid A on the first surface is the value described in the following Table 1, and forms coating liquid films formed by the water-based coating liquid A on both surfaces of the substrate. Then, the aluminum substrate with the coating liquid films formed by the water-based coating liquid A on both surfaces passes through a drying mechanism adjusted to 60° C., thereby drying the coating liquid film.

[0256] Films were formed on both surfaces of the aluminum substrate in the above manner to obtain a laminate consisting of the film, the aluminum substrate, and the film.

[0257] Here, the water-based coating liquid A is applied to the first surface in the area where the aluminum substrate is wound around the support roller 20, and the water-based coating liquid A is applied to the second surface in the area where the aluminum substrate is bent along the outer peripheral surface of the roller-shaped floating conveying mechanism. In addition, the conveying speed of the substrate is 20 m / min. In addition, other conditions, the radius of curvature of the curved conveying path, the distance of the curved conveying path, and the ratio of the distance from the starting point of the curve to the point where the second coating liquid is applied to the distance of the curved conveying path are set to the values ​​described in Table 1 below.

[0258] Furthermore, the floating amount of the substrate from the outer peripheral surface of the roller-shaped floating transport mechanism was set to 200 μm.

[0259] [Examples 2 to 13]

[0260] A laminate was obtained in the same manner as in Example 1 except that the solid content concentration of the first coating liquid film when applying the second coating liquid, the curvature radius of the curved conveying path, the distance of the curved conveying path, and the ratio of the distance from the bending starting point to the application start point of the second coating liquid relative to the distance of the curved conveying path were appropriately changed as described in the following Table 1.

[0261] [Examples 14 and 15]

[0262] Except that the aqueous coating liquid A was changed to the aqueous coating liquid B, a laminated body was obtained by the same method as in Examples 1 and 2, respectively.

[0263] [Comparative Example 1]

[0264] A laminate was obtained by the same method as in Example 1, except that after the water-based coating liquid A was initially applied to the first surface, the coating liquid film of the water-based coating liquid A formed on the first surface was dried (after the solid content concentration of the coating liquid film formed by the water-based coating liquid A became 100% by mass), and then the water-based coating liquid A was initially applied to the second surface.

[0265] [Examples 16 and 17]

[0266] Except that the type of the substrate was changed as shown in the following Table 2, films were formed on both surfaces of the substrate in the same manner as in Example 1 to obtain a laminate.

[0267] In Examples 16 and 17, the displacement F of the substrate when the water-based coating liquid A was first applied to the second surface and the solid content concentration of the coating liquid film formed of the water-based coating liquid A on the first surface are shown in Table 2 below.

[0268] In Examples 16 and 17, the amount of misalignment between the width of the first coating liquid film on the first surface (i.e., the coating liquid film formed by the aqueous coating liquid A formed on the first surface) and the width of the second coating liquid film formed by the second coating liquid on the second surface (i.e., the coating liquid film formed by the aqueous coating liquid A formed on the second surface) is recorded in Table 2 below.

[0269] [Examples 18 to 20]

[0270] Except that the thickness of the first coating liquid film formed on the first surface and the thickness of the second coating liquid film formed on the second surface were appropriately changed as shown in Table 2 below, films were formed on both surfaces of the aluminum substrate in the same manner as in Example 1 to obtain a laminate.

[0271] In Examples 18 to 20, the displacement F of the aluminum substrate when the water-based coating liquid A was first applied to the second surface and the solid content concentration of the coating liquid film formed by the water-based coating liquid A on the first surface are shown in Table 2 below.

[0272] In the present Examples 18 to 20, the amount of misalignment between the width of the first coating liquid film on the first surface (i.e., the coating liquid film formed by the aqueous coating liquid A formed on the first surface) and the width of the second coating liquid film formed by the second coating liquid on the second surface (i.e., the coating liquid film formed by the aqueous coating liquid A formed on the second surface) is recorded in the following Table 2.

[0273] [Various measurements]

[0274] The solid content concentration of the coating liquid film formed on the first surface of the aluminum substrate was measured by the method described above.

[0275] Furthermore, the curvature radius of the curved conveying path, the distance of the curved conveying path, and the ratio of the distance from the bending start point to the application start point of the second coating liquid to the distance of the curved conveying path were measured by the above-described method.

[0276] Furthermore, the amount of displacement between the width of the first coating liquid film on the first surface and the width of the second coating liquid film formed of the second coating liquid on the second surface was measured by the method described above.

[0277] In addition, the amount of misalignment between the width of the dry film of the first coating liquid film on the first surface (i.e., the dry film of the coating liquid film formed by the aqueous coating liquid A formed on the first surface) and the width of the dry film of the second coating liquid film formed by the second coating liquid on the second surface (i.e., the dry film of the coating liquid film formed by the aqueous coating liquid A formed on the second surface) was measured only for Comparative Example 1. This measurement was performed in the same manner as the amount of misalignment between the width of the first coating liquid film on the first surface and the width of the second coating liquid film on the second surface.

[0278] The results are shown in Tables 1 and 2.

[0279] [Evaluation of curling at the width direction end of substrate]

[0280] The curling of the width direction end portions of the laminated body obtained in each example was evaluated.

[0281] First, the laminate obtained in each example was measured. Figure 2 The curl amount C of the width direction end portion is shown. Figure 2 This is a schematic diagram of a main part of a cross section of a curled laminate cut along the width direction.

[0282] like Figure 2 As shown, the lifting amount of the width direction end portion of the laminate (ie, substrate) is measured with a ruler with the center portion of the laminate as a reference, and this is taken as the curling amount C of the width direction end portion of the laminate.

[0283] Based on the obtained value of the curl amount C, evaluation was performed according to the following criteria.

[0284] -Evaluation Criteria-

[0285] G1: Curl amount C is less than 2 mm

[0286] G2: Curl amount C is greater than 2mm and less than 5mm

[0287] G3: Curl amount C is greater than 5mm

[0288] The results are shown in Tables 1 and 2.

[0289]

[0290]

[0291] As is clear from Tables 1 and 2, according to the method for producing a laminate of the example, the amount of misalignment is reduced and the curl of the obtained laminate is also small.

[0292] Furthermore, in the laminate obtained in the example, the offset between the width of the dry film of the first coating liquid film and the width of the dry film of the second coating liquid film was measured by the method described above, and it was confirmed that it was limited to 0.7 mm or less. Thus, since the laminate obtained in the example has dry films formed in substantially the same area on the first and second surfaces of the substrate, it is estimated that curling is reduced.

[0293] On the other hand, as is clear from Table 1, in the method for producing the laminate of Comparative Example 1, the amount of misalignment becomes large (that is, the amount of misalignment when the film is dried is large), and the curling of the laminate is also large.

[0294] Explanation of symbols

[0295] 10-belt-shaped substrate (conveying path), 20-supporting roller, 30-first coating mechanism, 40-floating conveying mechanism, 50-second coating mechanism, 60-drying mechanism, P1-bending starting point of the curved conveying path, P2-bending ending point of the curved conveying path, P3-coating starting point of the second coating liquid.

[0296] All disclosed contents of Japanese Patent Application No. 2020-210736 filed on December 18, 2020 are incorporated into this specification by reference. All documents, patent applications, and technical standards described in this specification are incorporated into this specification by reference to the same extent as if each document, patent application, and technical standard was specifically and separately described as being incorporated by reference.

Claims

1. A method for manufacturing a laminate, which is a roll-to-roll continuous process, comprising the following steps: Step 1, preliminarily investigating changes in the solid content concentration of a first coating liquid film formed by the first coating liquid, determining a position on the conveying path where the solid content concentration of the first coating liquid film formed on the first surface of the substrate is 40 mass % to 80 mass %, Step 2, setting a region where the substrate is transported along the transport path bent by applying pressure to the first surface side by gas and setting a setting position of a coating mechanism for coating the second coating liquid at a position on the transport path determined in step 1, Step 3, for the substrate being continuously transported on the transport path, starting to apply the first coating liquid to the first surface of the substrate, and starting to apply the second coating liquid to the second surface opposite to the first surface of the substrate at the position on the transport path determined by step 1, The misalignment amount between the width of the first coating liquid film formed by the first coating liquid on the first surface and the width of the second coating liquid film formed by the second coating liquid on the second surface is within 1 mm.

2. The method for producing a laminate according to claim 1, wherein: The thickness of the substrate is 5 μm or more and 80 μm or less.

3. The method for producing a laminate according to claim 1 or 2, wherein: The film thickness of the first coating liquid film and the second coating liquid film is 40 μm or more.

4. The method for producing a laminate according to claim 1 or 2, wherein: The curvature radius of the curved conveying path is 100 mm to 500 mm.

5. The method for producing a laminate according to claim 1 or 2, wherein: The distance of the curved conveying path is 350 mm to 1750 mm.

6. The method for producing a laminate according to claim 1 or 2, wherein: The distance from the bending start point of the curved conveying path to the application start point of the second coating liquid is 50±25% of the distance of the curved conveying path.

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