JP7832121B2 - Manufacturing method for multilayer films - Google Patents

Description

This disclosure relates to a method for manufacturing multilayer films.

Various methods have been investigated for applying a coating solution to a long film that is in continuous motion. For example, Patent Document 1 below discloses a coating method characterized in that a plurality of dies are arranged in parallel opposite to a back roll that supports a long support that is being transported, in the width direction of the support, and a coating layer is formed.

Japanese Patent Publication No. 2002-28554

A method of applying a coating solution onto a wide film, such as the method disclosed in Patent Document 1, results in a multilayer film that is typically cut according to the width of the product. On the other hand, cutting the film after applying the coating solution can increase the cost of manufacturing the product. For example, the increased equipment costs associated with introducing a process to cut the film after applying the coating solution, or losses incurred in downstream processes after the coating solution is applied, increase the cost of manufacturing the product. Furthermore, wide films are prone to wrinkling due to thermal shrinkage, for example. These circumstances can lead to a decrease in productivity. There is also a need for a method to increase the amount of film processed during the coating solution application process.

One aspect of this disclosure aims to provide a method for manufacturing a multilayer film with excellent productivity.

This disclosure includes the following aspects:
<1> A method for manufacturing a multilayer film, comprising simultaneously conveying multiple films onto a roller including its outer surface, and applying a coating liquid to the multiple films being conveyed in parallel on the outer surface of the roller.
<2> A method for manufacturing a multilayer film according to <1>, comprising detecting the position of one end in the width direction of each of the plurality of films to which the above coating liquid has been applied, and controlling the transport position of each of the plurality of films according to the above position.
<3> The method for manufacturing a multilayer film according to <2>, wherein the control of the transport position includes changing at least one of the pressure and angle of the position control member while each of the plurality of films is passed between the roller and a position control member which is positioned upstream of the application position of the coating liquid in the transport direction of the plurality of films and opposite to the roller, and which controls the transport position of the film.
<4> The method for manufacturing a multilayer film according to <3>, wherein the control of the transport position includes bringing the position control member into contact with at least a portion of the widthwise end region of each of the plurality of films.
<5> A method for manufacturing a multilayer film according to any one of <1> to <4>, comprising controlling the tension of each film in the plurality of films described above.
<6> A method for manufacturing a multilayer film according to any one of <1> to <5>, comprising simultaneously supplying the above-mentioned multiple films using a feeding device that includes a plurality of tension-driven rollers, and controlling the tension of each of the above-mentioned multiple films using the feeding device.
<7> A method for manufacturing a multilayer film according to any one of <1> to <6>, comprising winding up the plurality of films coated with the coating liquid simultaneously using a winding device that includes a plurality of tension-driven rollers, and controlling the tension of each film in the plurality of films using the winding device.

According to one aspect of this disclosure, a method for manufacturing a multilayer film having excellent productivity is provided.

Figure 1 is a schematic side view illustrating a method for manufacturing a multilayer film according to one embodiment of the present disclosure. Figure 2 is a schematic perspective view showing an enlarged view of the dashed line area shown in Figure 1. Figure 3 is a schematic plan view showing an enlarged view of the dashed line area shown in Figure 1. Figure 4 is a schematic side view illustrating a method for manufacturing a multilayer film according to one embodiment of the present disclosure. Figure 5 is a schematic plan view showing an enlarged view of the dashed line area shown in Figure 4. Figure 6 is a schematic front view illustrating the method of using the position control member shown in Figures 4 and 5.

The embodiments of this disclosure are described in detail below. This disclosure is not limited to the embodiments described below. The embodiments described below may be modified as appropriate within the scope of the purposes of this disclosure.

When describing embodiments of this disclosure with reference to the drawings, explanations of redundant components and reference numerals in the drawings may be omitted. Components indicated by the same reference numeral in the drawings are considered to be the same component. Dimensional ratios in the drawings do not necessarily represent actual dimensional ratios.

In this disclosure, numerical ranges indicated using "~" represent ranges that include the numerical values before and after "~" as the lower and upper limits, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values shown in the examples.

In this disclosure, the amount of each component in a composition means the total amount of multiple substances present in the composition, unless otherwise specified, if there are multiple substances corresponding to each component in the composition.

In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that the intended purpose of the process is achieved.

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

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

In this disclosure, "solids" means components other than the solvent.

<Manufacturing method for multilayer films>
A method for manufacturing a multilayer film according to one embodiment of the present disclosure includes simultaneously conveying a plurality of films onto a roller including an outer surface, and applying a coating liquid to the plurality of films being conveyed in parallel on the outer surface of the roller. Hereinafter, "simultaneously conveying a plurality of films onto a roller including an outer surface" may be referred to as the "conveying step," and "applying a coating liquid to the plurality of films being conveyed in parallel on the outer surface of the roller" may be referred to as the "coating step." According to the above embodiment, a method for manufacturing a multilayer film with excellent productivity is provided.

Conventional methods (see, for example, Patent Document 1 above) apply a coating solution to a single film being transported on the outer surface of a roller, whereas a method for manufacturing a multilayer film according to one embodiment of the present disclosure applies a coating solution to multiple films being transported in parallel on the outer surface of a roller. Therefore, according to one embodiment of the present disclosure, the amount of film processed during the coating process is increased, and a method for manufacturing a multilayer film with excellent productivity is provided. Furthermore, regarding productivity, the method for manufacturing a multilayer film according to one embodiment of the present disclosure is considered to have the following advantages compared to conventional methods (see, for example, Patent Document 1 above). For example, even if the sum of the widths of multiple films being transported in parallel on the outer surface of a roller is large, the wrinkle occurrence rate is reduced because the width of each film becomes relatively narrower. Depending on the width of the film used, a reduction in losses in downstream processes or a reduction in the process of cutting the film after coating can also be expected.

The following describes each step in the manufacturing method of multilayer films in detail.

<<Conveying Process>>
In the conveying process, multiple films are conveyed simultaneously on a roller that includes the outer surface (hereinafter sometimes referred to as "roller CR"). "Conveying multiple films simultaneously" means that at least two films are in motion. In the conveying process, it is preferable to convey multiple films in parallel on the roller CR simultaneously.

(Roller CR)
The roller CR supports multiple films that are conveyed in parallel during the coating process described later. Examples of components of the roller CR include metals. Examples of metals include iron and chromium. The metal may also be an alloy. An example of an alloy is stainless steel. The roller CR may contain one or more metals.

The outer surface of the roller CR may be subjected to a surface treatment. Examples of surface treatments include plating.

The roller CR may be rotatable. A rotatable roller improves the film transportability in the coating process described later.

The width of the roller CR is determined within a range that does not fall below the sum of the widths of the multiple films conveyed on the outer surface of the roller CR during the coating process described later. The width of the roller CR may be within the range of 1,000 mm to 3,000 mm.

The diameter of the roller CR is not limited. From the viewpoint of preventing deflection and reducing weight, the diameter of the roller CR is preferably in the range of 50 mm to 500 mm, more preferably in the range of 80 mm to 400 mm, and particularly preferably in the range of 100 mm to 300 mm. Reducing the deflection of the roller CR reduces, for example, the rate of wrinkle occurrence in the film.

(film)
Examples of film components include polymers and metals. Examples of polymers include polyethylene terephthalate, polyethylene naphthalate, and triacetylcellulose. The film may contain one or more polymers. Examples of metals include nickel, titanium, copper, aluminum, silver, and gold. The metal may be an alloy. Examples of alloys include stainless steel and Invar. The film may contain one or more metals. In one embodiment, each film in a plurality of films preferably contains a polymer, and more preferably contains at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and triacetylcellulose. Specific examples of films containing polymers include polyethylene terephthalate films, polyethylene naphthalate films, and triacetylcellulose films. In one embodiment, each film in a plurality of films preferably contains a metal, more preferably contains at least one selected from the group consisting of nickel, titanium, copper, aluminum, silver, and gold, even more preferably contains at least one selected from the group consisting of copper and aluminum, and particularly preferably contains aluminum. Specific examples of films containing metals include copper films and aluminum films.

The film may have high thermal conductivity. Examples of films with high thermal conductivity include films with a thermal conductivity of 200 W/(m·K) or higher. There is no upper limit to the thermal conductivity of the film. The thermal conductivity of the film may be 500 W/(m·K) or less. The thermal conductivity of the film is measured using the laser flash method. First, the film is cut at three locations along its width (specifically, 5 mm from both ends in the width direction and in the center of the width direction), with diameters of 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 that applies the laser flash method (e.g., LFA-502, Kyoto Electronics Manufacturing Co., Ltd.). The arithmetic mean of the three measured values is taken as the thermal conductivity of the film.

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

From the viewpoint of improving productivity, it is preferable that each film in a group of films be a long film. The length of each film in a group of films is preferably 10 m or more, more preferably 100 m or more, and particularly preferably 200 m or more. There is no upper limit to the length of the film. The upper limit of the length of each film in a group of films may be 1,000 m or 500 m. The length of each film in a group of films is usually within the range of 10 m to 1,000 m. "Film length" means the distance from end to end of the film in the direction of film transport.

The width of the film is not limited. From the viewpoint of improving productivity, films with a narrow width are preferably used. Using films with a narrow width (for example, films with a width close to the width of the product) can contribute to, for example, suppressing the occurrence of wrinkles, reducing the process of cutting the film after the coating process, or reducing losses when defects are discovered in downstream processes. From the above viewpoint, the width of each film in a plurality of films is preferably 1,100 mm or less, more preferably 900 mm or less, and particularly preferably 700 mm or less. The lower limit of the film width is not limited. The lower limit of the width of each film in a plurality of films may be 100 mm or 200 mm. The width of each film in a plurality of films is preferably in the range of 100 mm to 1,100 mm, more preferably in the range of 100 mm to 700 mm, and particularly preferably in the range of 200 mm to 700 mm.

The film thickness is not limited. From the viewpoint of preventing deformation (e.g., curling and wrinkling) and ease of handling, the thickness of each film in a plurality of films is preferably in the range of 3 μm to 50 μm, and more preferably in the range of 10 μm to 30 μm.

(Transportation)
Multiple films are transported, for example, using a known transport device. The transport device may include a tension control mechanism for controlling the tension of the film. Examples of transport devices include transport rollers and transport belts. Other examples of transport devices include a feeder for feeding out film and a winder for winding up film. The feeder and winder can also be used, for example, as a roll-to-roll transport device. A roll-to-roll transport device is preferably used as a device for transporting long films. A roll-to-roll transport method includes, for example, supplying film from a roll of film and winding the film into a roll. The film wound into a roll forms a roll film. "Roll film" means film wound into a roll. Preferably, at least one of the feeder and winder includes a plurality of tension-driven rollers. A dispensing device including multiple tension-driven rollers can carry multiple rolls of film and supply film from each roll. A winding device including multiple tension-driven rollers can wind multiple films simultaneously and carry multiple rolls of film. The tension-driven rollers rotate, for example, by friction or magnetic force acting between the rotating shaft supporting the tension-driven rollers and the tension-driven rollers themselves. The rotating shaft is rotated, for example, by a motor. That is, the force that rotates the rotating shaft is transmitted to the tension-driven rollers, causing them to rotate. Preferably, the multiple tension-driven rollers are arranged along a single rotating shaft. A conveying device including tension-driven rollers (e.g., a dispensing device and a winding device) can control the tension of the film according to the rotation speed of the rotating shaft, for example. Technology relating to tension-driven rollers is described, for example, in Japanese Patent Publication No. 4066904. The contents of the above-mentioned document are incorporated herein by reference.

Multiple films may be transported at the same or different transport speeds. Preferably, the transport speeds of the multiple films are controlled independently. Preferably, the transport speed of each film in the multiple films is within the range of 1 m/min to 100 m/min.

The film in the conveying process may be supplied from a roll film. A roll film can supply long films. From the viewpoint of improving productivity, it is preferable that the multiple films in the conveying process be supplied from multiple roll films. In the above method, each film in the multiple films is supplied from a roll film. A method for manufacturing a multilayer film according to one embodiment of the present disclosure preferably includes supplying the multiple films simultaneously using a delivery device that includes multiple tension-driven rollers. For example, multiple long films are supplied by feeding films from each roll film in a plurality of roll films arranged along the rotation axis of the delivery device. Furthermore, a method for manufacturing a multilayer film according to one embodiment of the present disclosure more preferably includes supplying the multiple films simultaneously using a delivery device that includes multiple tension-driven rollers, and controlling the tension of each film in the multiple films using the delivery device. It is preferable that the tension of each of the multiple films be controlled independently. Tension control is effective, for example, in a method of supplying film from a roll film. As the diameter of the roll film decreases with the supply of film, the appropriate tension may change depending on the diameter of the roll film. When the tension of the film is controlled according to the change in the diameter of the roll film, for example, the occurrence of uneven coating in the coating process described later can be suppressed. However, the method of supplying the film in the conveying process is not limited to the method described above. Multiple films in the conveying process may be supplied by the film splitting process described later.

<<Coating process>>
In the coating process, the coating solution is applied to multiple films that are being transported in parallel on the outer surface of the roller CR. Applying the coating solution to multiple films that are being transported in parallel on the outer surface of the roller CR improves productivity.

(Application)
Examples of coating methods include curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar coating. In the coating process, it is preferable to apply the coating solution by the slot coating method. In the slot coating method, for example, a slot die is used as the coating device. A slot die is a coating device that includes a gap for discharging the coating solution. The slot die may be a known slot die. In the coating process, it is preferable to apply the coating solution using a slot die. In the coating process, one or more coating devices may be used.

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

(Application solution)
The type of coating solution is not limited. The type of coating solution is determined, for example, according to the application of the multilayer film. The coating solution is preferably an aqueous coating solution. "Aqueous coating solution" means a coating solution in which the solvent contained in the coating solution is substantially water. "The solvent contained in the coating solution is substantially water" means that water accounts for the majority of the solvent contained in the coating solution. The proportion of water in the solvent contained in the aqueous coating solution is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

Examples of water contained in aqueous coating solutions include natural water, purified water, distilled water, ion-exchanged water, pure water, and ultrapure water.

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

The aqueous coating solution may contain particles. Examples of particles include inorganic particles, organic particles, and composite particles of inorganic and organic substances.

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

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

Examples of composite particles of inorganic and organic materials include composite particles in which inorganic particles are dispersed in a matrix of organic material, composite particles in which organic particles are coated with inorganic material, and composite particles in which inorganic particles are coated with organic material.

To impart dispersibility, the particles may be surface-treated. Composite particles may be formed by the surface treatment.

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

The aqueous coating solution may contain one or more types of particles.

The particle content in the aqueous coating solution is not limited. The particle content in the aqueous coating solution is determined, for example, according to the purpose of particle addition, the coating film formed by the coating solution, and the manufacturing conditions of the coating film.

Components of an aqueous coating solution include, for example, binder components, components that contribute to particle dispersibility, polymerizable compounds, polymerization initiators, and components that enhance coating performance (e.g., surfactants).

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

<<Other processes>>
A method for manufacturing a multilayer film according to one embodiment of the present disclosure may include steps other than those described above, if necessary.

(Film splitting process)
A method for manufacturing a multilayer film according to one embodiment of the present disclosure may include dividing one film into multiple films (hereinafter referred to as the "film dividing step" in this paragraph) and simultaneously transporting the multiple films to a roller CR (i.e., a transport step). That is, the multiple films may be supplied by dividing one film. For example, after multiple roll films are prepared by the film dividing step, multiple films may be supplied from the multiple roll films. The film dividing step may be carried out in a series of processes including a transport step and a coating step. For example, in a roll-to-roll system, the film dividing step, transport step, and coating step may be carried out between the supply of rolled film and the winding of the film. The film dividing step may be carried out near the roller CR. For example, after multiple films are formed from one film near the roller CR in the film transport path, the multiple films may be transported in parallel on the outer surface of the roller CR. As a method for dividing the film, for example, a method of cutting the film using a blade can be mentioned. For example, one film can be divided into multiple films by cutting one film along the transport direction using a blade. The film splitting process may be carried out while the film is being transported.

(drying process)
A method for manufacturing a multilayer film according to one embodiment of the present disclosure may include drying the coating solution after the coating step. Examples of drying methods include heating and blowing air. The temperature of the gas used in blowing air is preferably in the range of 25°C to 200°C, and more preferably in the range of 30°C to 150°C. The air velocity used in blowing air is preferably in the range of 1.5 m/sec to 50 m/sec. Examples of drying equipment used to dry the coating solution include ovens, hot air blowers, and infrared heaters.

(Process for controlling the transport position)
A method for manufacturing a multilayer film according to one embodiment of the present disclosure preferably includes detecting the position of one end in the width direction of each film in a plurality of films to which a coating solution has been applied, and controlling the transport position of each film in the plurality of films according to the above position. Such a method suppresses meandering of the film and improves the accuracy of the application position of the coating solution in the width direction of the film. As a result, the coating solution is applied to a desired area of the film. In addition, in such a method, the positions of both ends in the width direction of the film may be detected, not just the position of one end in the width direction of the film.

The method for detecting the film position is not limited. The film position can be detected, for example, using a known sensor. Examples of sensors include a two-dimensional laser displacement meter and an image sensor. Preferably, the sensor is positioned downstream of the coating liquid application position and facing the roller CR in the transport direction of the multiple films. The sensor positioned as described above detects the position of one end of the film in the width direction immediately after the coating process, improving the accuracy of the coating liquid application position in the width direction of the film.

The method for controlling the film transport position is not limited. The film transport position can be controlled, for example, using a known edge position control (EPC) device. EPC devices are known as devices that detect the position of the film's edge while suppressing film meandering.

The control of the transport position preferably involves changing at least one of the pressure and angle of a position control member while passing each of the multiple films between the roller CR and a position control member positioned upstream of the application position of the coating liquid in the transport direction of the multiple films and facing the roller CR, and controlling the transport position of the film. The above method improves the controllability of the transport position of the film and the accuracy of the application position of the coating liquid in the width direction of the film. The pressure of the position control member is the pressure that the position control member applies to the film. Depending on the change in the pressure of the position control member, the film can be moved to the left or right with respect to the transport direction of the film. The amount of change in the pressure of the position control member may be within the range of 0.01 MPa to 0.5 MPa. The angle of the position control member is the angle of the position control member with respect to the transport direction of the film in a plan view. Depending on the change in the angle of the position control member, the film can be moved to the left or right with respect to the transport direction of the film. The amount of change in the angle of the position control member may be within the range of ±1 degree. Specific examples of how to use the position control member are described in the "Production Method" section below.

The control of the transport position preferably includes contacting a position control member with at least a portion of each film in a plurality of films. More preferably, the control of the transport position includes contacting a position control member with a portion of each film in a plurality of films. Particularly preferably, the control of the transport position includes contacting a position control member with at least a portion of the widthwise end region of each film in a plurality of films. The above method improves the controllability of the transport position of the film and improves the accuracy of the application position of the coating liquid in the width direction of the film. The "widthwise end region of the film" is an area that extends in the length direction of the film (i.e., the transport direction of the film) and has a predetermined width in the width direction of the film from the end of the film toward the center of the film. The widthwise end region may be defined near one end of the film in the width direction or near both ends of the film in the width direction. From the viewpoint of improving the controllability of the transport position of the film, the width of the widthwise end region of the film is preferably 1/3 of the film width, more preferably 1/4 of the film width, and particularly preferably 1/5 of the film width.

The position control member may be rotatable. A rotatable position control member improves the transportability of the film.

Examples of the shape of the position control member include a cylinder and a frustum of a cone. In the case of a frustum of a cone position control member, the angle between the base and the side surface is preferably 60 to 87 degrees. The term "base" used in relation to a frustum of a cone refers to the surface with the largest diameter among the two circular planes contained in the frustum of a cone.

The diameter of the position control member is preferably in the range of 10 mm to 100 mm. From the viewpoint of improving the controllability of the film transport position, the diameter of the position control member is preferably smaller than the diameter of the roller CR.

From the viewpoint of improving the controllability of the film transport position, the width of the position control member is preferably in the range of 5 mm to 100 mm, and more preferably in the range of 10 mm to 50 mm.

From the viewpoint of improving the controllability of the film transport position, the ratio of the width of the position control member to the width of the film is preferably in the range of 1/100 to 1/5, more preferably in the range of 1/80 to 1/8, and particularly preferably in the range of 1/50 to 1/10. The ratio of the width of the position control member to the width of the film is calculated based on the width of the film to be measured and the width of the position control member in contact with the film to be measured. From the viewpoint of improving the controllability of the film transport position, the ratio of the width of the position control member to the width of the roller CR is preferably in the range of 1/500 to 1/10, more preferably in the range of 1/200 to 1/20, and particularly preferably in the range of 1/100 to 1/30.

The number of position control members is determined, for example, according to the number of film rows in a plurality of films being conveyed in parallel on the outer surface of the roller CR. The number of position control members may be the same as the number of film rows in a plurality of films being conveyed in parallel on the outer surface of the roller CR. The number of position control members may exceed the number of film rows in a plurality of films being conveyed in parallel on the outer surface of the roller CR. From the viewpoint of improving the controllability of the film conveying position, it is preferable that the number of position control members be equal to or greater than the number of film rows in a plurality of films being conveyed in parallel on the outer surface of the roller CR. From the viewpoint of improving the controllability of the film conveying position, it is preferable that the number of position control members that contact each film in a plurality of films being conveyed in parallel on the outer surface of the roller CR is at least one, and preferably one or two.

Examples of components of the position control member include polymers and metals. Examples of polymers include polyurethane, acrylonitrile-butadiene rubber (abbreviated as NBR), ethylene-propylene-diene rubber (abbreviated as EPDM), and fluororubber. The position control member may contain one or more polymers. Examples of metals include iron and chromium. The metal may be an alloy. Examples of alloys include stainless steel. The position control member may contain one or more metals. The position control member may be formed from a plurality of components.

The position control member is preferably elastic. An elastic position control member improves the controllability of the film's transport position. Examples of components of the elastic position control member include rubber. The rubber may be natural rubber or synthetic rubber. Examples of rubber include urethane rubber, acrylonitrile-butadiene rubber (abbreviated as NBR), ethylene-propylene-diene rubber (abbreviated as EPDM), and fluororubber. The position control member preferably contains at least one selected from the group consisting of urethane rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, and fluororubber. The hardness of the rubber is preferably 20 to 90 degrees, and more preferably 30 to 80 degrees. A hardness of 30 degrees or more improves durability. A hardness of 80 degrees or less suppresses the bouncing of the position control member when it comes into contact with the film. The position control member may also contain a rubber layer. The rubber layer may be arranged to cover at least a portion of the surface of any member (e.g., a metal member) that constitutes the position control member. The position control member preferably includes a rubber layer as a surface layer. The thickness of the rubber layer is preferably in the range of 1 mm to 50 mm, and more preferably in the range of 2 mm to 20 mm.

(Tension control)
A method for manufacturing a multilayer film according to one embodiment of the present disclosure preferably includes controlling the tension of each film in a plurality of films. Preferably, the tensions of the plurality of films are controlled independently. Controlling the tension contributes to the uniform application of the coating liquid. Furthermore, controlling the tension is effective, for example, in a method in which each film is supplied from a roll film. As the diameter of the roll film decreases over time, the appropriate tension may change depending on the diameter of the roll film. Therefore, by controlling the tension of the film in accordance with the change in the diameter of the roll film, the occurrence of uneven coating can be suppressed. The tension of each film in a plurality of films is preferably in the range of 30 N/m to 300 N/m, and more preferably in the range of 150 N/m to 250 N/m. Controlling the tension is carried out, for example, using a known tension control device. Controlling the tension may also be carried out using a known conveying device that includes a tension control mechanism. Controlling the tension may also be carried out using at least one of a dispensing device and a winding device. A preferred dispensing device is, for example, a dispensing device including a plurality of tension-driven rollers as described in the "Conveying Process" section above. A preferred winding device is, for example, a winding device including a plurality of tension-driven rollers as described in the "Conveying Process" section above.

(Film winding)
A method for manufacturing a multilayer film according to one embodiment of the present disclosure preferably includes simultaneously winding up a plurality of films coated with the coating solution using a winding device that includes a plurality of tension-driven rollers. In the above method, for example, a plurality of roll films can be mounted on the winding device by arranging a plurality of roll films along the rotation axis of the winding device. The technology relating to the tension-driven rollers is described in the "Conveying Process" section above. A method for manufacturing a multilayer film according to one embodiment of the present disclosure more preferably includes simultaneously winding up a plurality of films coated with the coating solution using a winding device that includes a plurality of tension-driven rollers, and controlling the tension of each film in the plurality of films using the winding device.

(Cutting process for multilayer film)
A method for manufacturing a multilayer film according to one embodiment of this disclosure may include a step of cutting the multilayer film. By cutting the multilayer film, the width of the multilayer film can be adjusted. Examples of methods for cutting the multilayer film include using a cutting tool.

<<Production Method>>
From the viewpoint of improving productivity, the method for manufacturing a multilayer film according to one embodiment of this disclosure is preferably carried out by a roll-to-roll method. In the method for manufacturing a multilayer film carried out by a roll-to-roll method, at least a conveying 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 Figures 1, 2, and 3. Figure 1 is a schematic side view illustrating a method for manufacturing a multilayer film according to one embodiment of this disclosure. Figure 2 is a schematic perspective view showing an enlarged view of the dashed line portion shown in Figure 1. Figure 3 is a schematic plan view showing an enlarged view of the dashed line portion shown in Figure 1.

The manufacturing apparatus 100 shown in Figure 1 includes a conveyor roller 10, a conveyor roller 11, a conveyor roller 12, a conveyor roller 13, a conveyor roller 14, a conveyor roller 15, a conveyor roller 16, a backup roller 20, a slot die 30, a sensor 40, a position control member 50, a drying device 60, a dispensing device (not shown), and a winding device (not shown).

The transport rollers 10, 11, 12, 13, 14, 15, 16, and backup roller 20 transport the film F while supporting it. Each roller is rotatable. The backup roller 20 corresponds to the roller CR described above.

The slot die 30 dispenses the coating liquid onto the film F. The coating liquid is supplied from a liquid delivery device (not shown) connected to the slot die 30. In the multilayer film manufacturing method shown in Figure 1, two slot dies 30 are used. As shown in Figures 2 and 3, the two slot dies 30 are arranged along the width direction of the backup roller 20. Each slot die 30 is positioned opposite the backup roller 20. Alternatively, a single slot die capable of dispensing coating liquid onto two films F may be used instead of two slot dies 30.

The sensor 40 detects the position of one end of the film F in the width direction. In the multilayer film manufacturing method shown in Figure 1, two sensors 40 are used. As shown in Figure 2, the two sensors 40 are arranged along the width direction of the backup roller 20. Each sensor 40 is positioned downstream of the coating position of the coating liquid discharged from the slot die 30 in the transport direction of the film F, and facing the backup roller 20.

The position control member 50 controls the transport position of the film F according to the position of the film F detected using the sensor 40. In the multilayer film manufacturing method shown in Figure 1, two position control members 50 are used. As shown in Figure 3, the two position control members 50 are aligned along the width direction of the backup roller 20. Each position control member 50 is positioned upstream of the application position of the coating liquid discharged from the slot die 30 in the transport direction of the film F, and facing the backup roller 20. Each position control member 50 is in contact with at least a portion of the width direction end region of the film F. Each position control member 50 is cylindrical in shape. Each position control member 50 is rotatable. The line passing through the center of each position control member 50 during rotational motion is parallel to the width direction of the backup roller 20.

The drying apparatus 60 dries the coating liquid applied to the film F.

The feeding device (not shown) supplies film F from roll film RF1. The feeding device includes a plurality of tension-driven rollers rotatably supported on the outer circumference of a rotating shaft. The feeding device has two roll films RF1 mounted along the rotating shaft that extends from front to back in Figure 1.

The winding device (not shown) forms a roll film RF2 by winding a multilayer film containing film F into a roll. The winding device includes a plurality of tension-driven rollers rotatably supported on the outer circumference of a rotating shaft. The winding device mounts two roll films RF2 along the rotating shaft that extends from the front to the back in Figure 1.

The manufacturing method for the multilayer film shown in Figure 1 is carried out by a roll-to-roll method. In the manufacturing method for the multilayer film shown in Figure 1, two roll films RF1 are used. The two roll films RF1 are arranged from front to back in Figure 1. Each roll film RF1 supplies film F. The film F fed out from each roll film RF1 passes through transport rollers 10, 11, 12, 13, backup roller 20, drying device 60, transport rollers 14, 15, and 16, and is wound into a roll. In Figure 1, two long films F are transported in parallel and simultaneously.

As shown in Figures 2 and 3, the two films F that reach the backup roller 20 are transported in parallel along the outer surface of the backup roller 20. The two films F are aligned along the width direction of the backup roller 20. The number of films lined up on the outer surface of the backup roller 20, i.e., the number of film rows, is two. The coating liquid discharged from the slot die 30 is applied to the two films F that are being transported in parallel on the outer surface of the backup roller 20. As shown in Figures 2 and 3, it is presumed that productivity will be improved by transporting the two films F in parallel on one backup roller 20 and applying the coating liquid to the two films F. Furthermore, by applying the coating liquid to two films F on one backup roller 20, it is also expected that the costs required for manufacturing equipment will be reduced.

In the multilayer film manufacturing method shown in Figure 1, the transport position of the film F is controlled by changing the angle of the position control member 50 while the film F passes between the backup roller 20 and the position control member 50. The angle of the position control member 50 is feedback controlled by a linear motor (not shown) according to the position of the film F detected using a sensor 40. In Figure 3, when the position control member 50 is tilted clockwise with respect to the transport direction of the film F, the film F can move to the right, and when the position control member 50 is tilted counterclockwise with respect to the transport direction of the film F, the film F can move to the left.

The coating liquid applied to film F is dried in drying apparatus 60. A multilayer film is formed by the drying of the coating liquid. The multilayer film is wound into a roll using a winding device (not shown). In the multilayer film manufacturing method shown in Figure 1, two roll films RF2 are formed along the rotation axis of the winding device (not shown), from the front to the back of Figure 1.

Next, another example of a method for manufacturing a multilayer film will be described with reference to Figures 4, 5, and 6. Figure 4 is a schematic side view illustrating a method for manufacturing a multilayer film according to one embodiment of the present disclosure. Figure 5 is a schematic plan view showing an enlarged view of the dashed line portion shown in Figure 4. Figure 6 is a schematic front view illustrating a method for using the position control member shown in Figures 4 and 5.

The manufacturing apparatus 110 shown in Figure 4 includes the same components as the manufacturing apparatus 100 shown in Figure 1, except for the position control member. Furthermore, the method for manufacturing the multilayer film shown in Figure 4 is the same as the method for manufacturing the multilayer film shown in Figure 1, except for the method for controlling the transport position of the film F.

Position control members 51A and 51B control the transport position of the film F according to the position of the film F detected using the sensor 40. In the multilayer film manufacturing method shown in Figure 4, two sets of position control members 51A and 51B are used. Position control members 51A and 51B are arranged along the width direction of the backup roller 20. Position control members 51A and 51B are positioned upstream of the application position of the coating liquid discharged from the slot die 30 in the transport direction of the film F, and facing the backup roller 20. The shape of position control members 51A and 51B is a frustocone. Position control members 51A and 51B are rotatable. The straight line passing through the center of the rotational motion of position control members 51A and 51B is parallel to the width direction of the backup roller 20.

In Figure 6, the position control members 51A and 51B are arranged along direction X. Direction X is parallel to the width direction of the backup roller 20. The position control members 51A and 51B move along direction Y by an air cylinder (not shown) and can contact at least a portion of the widthwise end region of the film F. Position control member 51A can contact the vicinity of one end of the film, and position control member 51B can contact the vicinity of the other end of the film. The film F is being transported from the front to the back in Figure 6. The pressure of the position control members 51A and 51B is feedback controlled by the air cylinder (not shown) according to the position of the film F detected using the sensor 40. In Figure 6, when the pressure of position control member 51B becomes greater than the pressure of position control member 51A, the film F can move to the right, and when the pressure of position control member 51A becomes greater than the pressure of position control member 51B, the film F can move to the left. The film F may be moved to the right by bringing only the position control member 51B into contact with the film F. The film F may be moved to the left by bringing only the position control member 51A into contact with the film F.

The present disclosure will be described in detail below with reference to examples. However, the present disclosure is not limited to the following examples.

<Example 1>
(Preparing the film)
An aluminum film with a width of 600 mm, a thickness of 10 μm, a length of 300 m, and a thermal conductivity of 230 W/(m·K) was prepared. The aluminum film was wound into a roll to form a roll film. In Example 1, two roll films were prepared.

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

The aqueous dispersion of Artpearl J-7P was prepared by the following method: 74 parts by mass of pure water was mixed with 3 parts by mass of Emarex 710 (Nippon Emulsion Co., Ltd., nonionic surfactant) and 3 parts by mass of sodium carboxymethylcellulose (Daiichi Kogyo Seiyaku Co., Ltd.). 20 parts by mass of Artpearl J-7P (Negami Kogyo Co., Ltd., silica composite crosslinked acrylic resin fine particles) were added to the resulting aqueous solution and dispersed at 10,000 rpm (revolutions per minute, hereafter the same) for 15 minutes using an Ace homogenizer (Nippon Seiki Seisakusho Co., Ltd.) to obtain the 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 was 1.20, and the average particle size was 6.5 μm.

(Manufacturing of multilayer films)
Using a manufacturing apparatus containing the components shown in Figure 1, coating solution A was applied to the film, and then the coating solution was dried. A multilayer film was obtained by this procedure. The film transport speed was 20 m/min. The diameter of the backup roller was 200 mm. The specific manufacturing conditions are shown in Table 1.

<Example 2>
A multilayer film was obtained using the same procedure as in Example 1, except that the manufacturing conditions were changed according to the information in Table 1.

<Example 3>
A multilayer film was obtained using the same procedure as in Example 1, except that a manufacturing apparatus containing the components shown in Figure 4 was used instead of a manufacturing apparatus containing the components shown in Figure 1.

<Example 4>
A multilayer film was obtained using the same procedure as in Example 3, except that the manufacturing conditions were changed according to the information in Table 1.

<Comparative Example 1>
A multilayer film was obtained using the same procedure as in Example 1, except that the manufacturing conditions were changed according to the information in Table 1.

<Evaluation>
(Wrinkles)
The appearance of the multilayer film in motion was visually inspected and evaluated according to the following criteria. The evaluation results are shown in Table 1.
A: No wrinkles formed on the film, or any wrinkles that formed on the film disappeared over time and returned to their original shape.
B: The film was permanently deformed due to the formation of wrinkles.

(Variations in application position)
The appearance of the obtained multilayer films was visually inspected and evaluated according to the following criteria. In the following criteria, "coating position" refers to the distance from the edge of the film to the edge of the coating in the width direction. The evaluation results are shown in Table 1.
A: The variation in the application position of the coating solution in the width direction of the film was less than 1 mm.
B: The variation in the application position of the coating solution in the width direction of the film was 1 mm or more.

In Table 1, the "angle" listed in the "Control of Conveying Position" column means that the film's conveying position was controlled by utilizing the change in the angle of the position control member, as shown in Figure 3. The position control member used in the above control method is a cylindrical roller. The diameter of the cylindrical roller is 80 mm. The width of the cylindrical roller is 20 mm. A rubber layer is formed on the outer surface of the cylindrical roller. The thickness of the rubber layer is 20 mm. The rubber layer contains acrylonitrile-butadiene rubber. The hardness of the acrylonitrile-butadiene rubber is 70 degrees. In the above control method, the width of the film's widthwise edge region is 1/5 of the film's width.

In Table 1, the "pressure" listed in the "Control of Conveying Position" column means that the conveying position of the film was controlled by utilizing the change in pressure of the position control member, as shown in Figure 6. The position control member used in the above control method is a frustoconical roller. The diameter of the frustoconical roller is 80 mm. The width of the frustoconical roller is 50 mm. A rubber layer is formed on the outer surface of the frustoconical roller. The thickness of the rubber layer is 20 mm. The rubber layer contains urethane rubber. The hardness of the urethane rubber is 40 degrees. In the above control method, the width of the film's widthwise edge region is 1/5 of the film's width.

Table 1 shows that a multilayer film was obtained by applying a coating solution to multiple films being transported in parallel on the outer surface of a backup roller. Table 1 also shows that controlling the transport position of each film improved the accuracy of the coating solution application position in the width direction of the film. Furthermore, Table 1 shows that even when the sum of the widths of the multiple films used in Examples 1 to 4 was the same as the width of the film used in Comparative Example 1, wrinkle formation was suppressed.

The disclosure of Japanese Patent Application No. 2020-201156, filed on 3 December 2020, is incorporated herein by reference. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually described as being incorporated by reference.

10, 11, 12, 13, 14, 15, 16: Conveyor rollers 20: Backup rollers 30: Slot dies 40: Sensors 50, 51A, 51B: Position control members 60: Drying equipment 100, 110: Manufacturing equipment F: Film RF1, RF2: Roll film

Claims (5)

The ability to simultaneously transport multiple films onto rollers, including the outer surface,
The coating liquid is applied to the plurality of films that are being conveyed in parallel on the outer surface of the roller,
To detect the position of one end in the width direction of each of the plurality of films to which the coating liquid has been applied,
The transport position of each film in the plurality of films is controlled according to the aforementioned position.
Includes ,
The control of the transport position includes changing at least one of the pressure and angle of the position control member while passing each of the plurality of films between the roller and a position control member positioned upstream of the application position of the coating liquid in the transport direction of the plurality of films and facing the roller, and controlling the transport position of the film.
A method for manufacturing a multilayer film comprising a film and a layer consisting of a dried product of the coating liquid . The method for manufacturing a multilayer film according to claim 1 , wherein the control of the transport position includes bringing the position control member into contact with at least a portion of the widthwise end region of each of the plurality of films. A method for manufacturing a multilayer film according to claim 1 or claim 2 , comprising controlling the tension of each film in the plurality of films. A method for manufacturing a multilayer film according to any one of claims 1 to 3, comprising: simultaneously supplying the plurality of films using a feeding device that includes a plurality of tension-driven rollers; and controlling the tension of each film in the plurality of films using the feeding device. A method for manufacturing a multilayer film according to any one of claims 1 to 4, comprising: simultaneously winding up the plurality of films coated with the coating liquid using a winding device including a plurality of tension-driven rollers ; and controlling the tension of each film in the plurality of films using the winding device.