Manufacturing method of sheet material and manufacturing device of sheet material

Abstract

To provide a manufacturing method of a sheet material which can inhibit generation of odor when ultraviolet light is radiated.SOLUTION: A manufacturing method of a sheet material includes: a step A in which a UV ink is applied to a first surface of a sheet-like base material to form an application layer; a step B in which a cover member is adhered to the application layer so as to cover the application layer; a step C in which ultraviolet light is radiated to the application layer covered with the cover member to harden the application layer and thereby form a coating layer; and a step D in which the cover member is peeled from the coating layer after the step C. The cover member has ultraviolet light transmissivity. A surface, which faces the application layer, in the cover member includes a release agent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for manufacturing a sheet material. [Background technology]

[0002] Patent Document 1 discloses a printing device that includes a print head that ejects UV ink and a UV irradiation device that irradiates the UV ink with ultraviolet light. The UV ink is cured by ultraviolet light. When the UV ink is cured to form a coating layer, an odor is generated. To solve the odor problem, the printing device of Patent Document 1 exhausts gas from the print head and the UV irradiation device. With this configuration, a sheet material having a coating layer on a sheet-like substrate can be manufactured.

[0003] It is known that one of the causes of the odor is oxygen present in the ultraviolet ray irradiation area. In order to reduce the effect of oxygen in the configuration of Patent Document 1, it is possible to introduce nitrogen into the ultraviolet ray irradiation area and eliminate oxygen from the irradiation area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-165208 A Summary of the Invention [Problem to be solved by the invention]

[0005] When introducing nitrogen into the ultraviolet irradiation area, it is necessary to provide not only an introduction device for introducing nitrogen, but also an exhaust device for exhausting nitrogen from the irradiation area so that nitrogen does not leak into the work space where the workers are present. These introduction devices and exhaust devices are large-scale, which leads to an increase in the size of the printing machine. In addition, maintenance of the introduction device and exhaust device is required. During this maintenance, the printing work is stopped.

[0006] An object of the present invention is to provide a method and an apparatus for manufacturing a sheet material that can suppress the generation of odors during irradiation with ultraviolet rays with a simple configuration. [Means for solving the problem]

[0007] (1) A method for producing a sheet material according to a first aspect of the present invention includes a step A of applying a UV ink to a first surface of a sheet-like substrate to form a coating layer, a step B of adhering a cover member to the coating layer so as to cover the coating layer, a step C of irradiating the coating layer covered with the cover member with ultraviolet light to harden the coating layer to form a coating layer, and a step D of peeling the cover member from the coating layer after step C. The cover member is ultraviolet ray transparent, and the surface of the cover member facing the coating layer contains a release agent.

[0008] UV ink is an ink that hardens by ultraviolet light. UV ink contains a photopolymerization initiator that absorbs ultraviolet light and generates radicals, and a photopolymerization resin that polymerizes by the generated radicals. If oxygen is present around the UV ink when irradiated with ultraviolet light, the oxygen bonds with the photopolymerization initiator, suppressing the polymerization reaction of the photopolymerization resin. In addition, the photopolymerization initiator that bonds with oxygen emits an odor. To address this problem, in the manufacturing method of the sheet material described in (1) above, ultraviolet light is irradiated onto the coating layer made of UV ink while the coating layer is covered with a cover member. Since the coating layer is shielded from the atmosphere when irradiated with ultraviolet light, the bonding between the photopolymerization initiator stimulated by ultraviolet light and oxygen is suppressed. Therefore, a substance in which the photopolymerization initiator and oxygen are bonded, which causes odor, is unlikely to be generated. In this configuration, there is no need to introduce nitrogen into the ultraviolet light irradiated area, and there is also no need for a configuration for exhausting nitrogen or a configuration for preventing nitrogen from leaking into the working space.

[0009] (2) In the method for manufacturing a sheet material described in (1) above, the cover member is a flexible resin film, the resin film has a base layer and a release agent layer, and the release agent layer may contain the release agent.

[0010] The cover member made of a resin film can be continuously supplied to the substrate as shown in the embodiment described later. Therefore, the coating layer formed on the substrate can be efficiently cured, and the productivity of the sheet material is improved. In addition, by dividing the cover member into a base layer and a release agent layer, the characteristics required for the cover member can be shared between the base part and the release agent layer. For example, the base layer can be made of a material that is difficult to stretch, and the resin film can be made difficult to stretch.

[0011] (3) In the method for producing a sheet material described in (2) above, the base layer may be made of a polyethylene terephthalate resin.

[0012] Polyethylene terephthalate resin (PET resin) is difficult to stretch. Resin films that are difficult to stretch are less likely to expand and contract due to changes in tension acting on the resin film, making them easier to place on a coating layer on a substrate and less likely to slip off the substrate after placement.

[0013] (4) In the method for producing a sheet material described in (2) or (3) above, the resin film may have a thickness of 15 μm or more and 50 μm or less.

[0014] If the thickness of the resin film is 15 μm or more, the resin film is less likely to wrinkle or stick to other resin films when handled. Therefore, a resin film having a thickness of 15 μm or more is easy to handle. If the thickness of the resin film is 50 μm or less, the resin film is easy to bend. A resin film that is easy to bend is easy to adhere to a coating layer, and air bubbles are less likely to be mixed in between the coating layer and the resin film.

[0015] (5) In the method for producing a sheet material according to any one of (1) to (4) above, the release agent may be a silicone resin.

[0016] Silicone resin is inexpensive and does not easily chemically bond with the coating layer made of UV ink when the UV ink hardens.

[0017] (6) In the method for producing a sheet material according to any one of (1) to (5) above, in the step A, the UV ink may be applied to the first surface by gravure printing.

[0018] According to the gravure printing, a coating layer can be formed uniformly on the first surface of the substrate. The gravure printing apparatus that performs the gravure printing has a relatively simple configuration and is not prone to breakdowns. Therefore, the production of the sheet material is not likely to be stopped due to breakdowns or maintenance of the gravure printing apparatus, and the productivity of the sheet material is not likely to decrease.

[0019] (7) In the method for manufacturing a sheet material described in any one of (2) to (4) above, the resin film taken up onto a pay-out drum by a first roller may be guided in a direction approaching the substrate to bring the resin film into close contact with the substrate, and in step D, the resin film may be guided in a direction away from the substrate by a second roller to take up the resin film onto a take-up drum.

[0020] The resin film is automatically supplied and collected, and by adjusting the rotation speed of the winding drum, the resin film can be positioned without misalignment relative to the substrate.

[0021] (8) In the method for manufacturing a sheet material described in any one of (1) to (7) above, the substrate may comprise a base sheet and a printing layer printed on the base sheet, and in step A, the coating layer may cover the printing layer.

[0022] In step A, the printed layer of the substrate is covered with the coating layer, thereby producing a sheet material in which the printed layer is covered with a coating layer. As a result, the printed layer is protected by the coating layer. In addition, since the coating layer has a glossy finish, the appearance of the printed layer through the coating layer is improved.

[0023] (9) The sheet material manufacturing apparatus of the present invention includes a conveying device for conveying a sheet-like substrate, a coating device for applying a UV ink to a first surface of the substrate to form a coating layer on the first surface, a placement device for bringing a cover member into close contact with the coating layer so as to cover the coating layer, an irradiation device for irradiating the coating layer covered with the cover member with ultraviolet light to form a coating layer by hardening the coating layer, and a peeling device for peeling the cover member from the coating layer. The cover member is ultraviolet-transmitting, and the surface of the cover member facing the coating layer contains a release agent.

[0024] The above-mentioned sheet material manufacturing apparatus can suppress the generation of odors during ultraviolet irradiation by disposing a cover member on the coating layer made of UV ink. This sheet material manufacturing apparatus does not require a configuration for introducing nitrogen into the ultraviolet irradiation area, or a configuration for exhausting nitrogen so that the nitrogen introduced into the irradiation area does not leak into the work space. The sheet material manufacturing apparatus, which does not require the trouble of repairing or maintaining the configuration related to the introduction and exhaust of nitrogen, can manufacture sheet materials with high productivity. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of a sheet material manufacturing apparatus according to an embodiment. [Diagram 2] FIG. 2 is a partially enlarged view of the sheet material manufacturing apparatus shown in FIG. [Diagram 3] FIG. 3 is a schematic diagram of the sheet material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, specific examples of the sheet material manufacturing method and sheet material manufacturing apparatus of the present invention will be described with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. The size of the members shown in each drawing is expressed for the purpose of clarifying the description, and does not necessarily represent the actual dimensions. Note that the present invention is not limited to these examples, but is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

[0027] <Embodiment 1> The method for manufacturing a sheet material according to the embodiment includes the following steps A to D. Step A: A UV ink is applied to the first surface of a sheet-like substrate to form a coating layer. Step B: A cover member is brought into close contact with the coating layer so as to cover the coating layer. Step C: The coating layer covered with the cover member is irradiated with ultraviolet light to harden the coating layer, thereby forming a coating layer. Step D: After step C, the cover member is peeled off from the coating layer.

[0028] The sheet material manufacturing apparatus shown in Fig. 1 is an example of a sheet material manufacturing apparatus 1 configured to be able to carry out the above-mentioned sheet material manufacturing method. Fig. 2 is an enlarged view of a portion surrounded by a dashed line in the sheet material manufacturing apparatus 1 shown in Fig. 1. The sheet material manufacturing apparatus 1 includes a conveying device 2, a coating device 3, a placement device 4, an irradiation device 5, and a peeling device 6. Below, each component of the sheet material manufacturing apparatus 1 will be described, along with the relationship with each step of the sheet material manufacturing method.

[0029] <Transportation device> The conveying device 2 of this example includes a delivery drum 20 and a winding drum 29. The conveying device 2 of this example further includes a plurality of guide rollers 21, 22. A sheet-shaped substrate 70 is wound around the delivery drum 20. The substrate 70 unwound from the delivery drum 20 is guided by the plurality of guide rollers 21, 22 and sent out toward the winding drum 29. The guide roller 22 also plays a role in applying tension to the substrate 70 so that the substrate 70 does not wrinkle in the irradiation area of ​​the irradiation device 5 described later. The guide roller 22 of this example is disposed above the delivery drum 20 and the winding drum 29. The substrate 70 is treated by a coating device 3 described later or the like to form a coating layer 75 (FIG. 2). The sheet material 7 consisting of the substrate 70 and the coating layer 75 is wound around the winding drum 29.

[0030] The shape of the substrate 70 in this example is a long sheet that can be rolled up. The substrate 70 may be a short sheet. When the substrate 70 is a short sheet, the transport device 2 may be a conveyor that transports the substrate 70 to an irradiation area of ​​the irradiation device 5 described later.

[0031] As shown in FIG. 3, the substrate 70 of this example includes a base sheet 70B and a printed layer 70P. The material of the base sheet 70B is not particularly limited. For example, the base sheet 70B is paper or plastic. The printed layer 70P is a layer consisting of characters, designs, or a combination thereof printed on the base sheet 70B. The printed layer 70P is formed by a known printing method, such as a gravure printing method. The printed layer 70P is not essential. In other words, the substrate 70 may be formed only by the base sheet 70B.

[0032] <Coating equipment> The coating device 3 is a device that coats the first surface 70s (FIG. 2) of the substrate 70 with UV ink. In other words, the coating device 3 is a device that performs step A of the manufacturing method of the sheet material. The coating device 3 forms a coating layer 71 (FIG. 2) made of UV ink on at least a part of the first surface 70s of the substrate 70. The first surface 70s in this example is a surface that faces upward when unwound from the delivery drum 20, and is the surface of the printing layer 70P in FIG. 3. In this example, the coating layer 71 is formed on the entire first surface 70s. The coating device 3 is not particularly limited as long as it is configured to coat the first surface 70s with UV ink. The coating device 3 may be, for example, a gravure printing device or an inkjet printing device. The coating device 3 in this example is a gravure printing device. The gravure printing device includes an ink pan that stores UV ink, a gravure roll 30 that coats the UV ink, and a doctor blade that removes excess UV ink attached to the gravure roll 30. In FIG. 1, only the gravure roll 30 in the gravure printing apparatus is shown.

[0033] UV ink is an ink that is cured by ultraviolet light. UV ink contains at least a photopolymerization resin and a photopolymerization initiator. The photopolymerization resin contains, for example, the following prepolymer and monomer. The prepolymer is, for example, polyol acrylate, epoxy acrylate, urethane acrylate, polyester acrylate, alkyd acrylate, or polyether acrylate. The monomer is, for example, monoacrylate, diacrylate, or triacrylate.

[0034] Photoinitiators are substances that absorb ultraviolet light to generate radicals, which then polymerize the prepolymer and monomer. Examples of photoinitiators include benzoin derivatives, benzil ketals, α-hydroxyacetophenone, α-acetophenone, benzophenone / amine, or Michler's ketone.

[0035] The UV ink may contain additives, such as colorants, lubricants, antioxidants, drying agents, wetting agents, viscosity modifiers, or waxes. The colorants may be, for example, organic pigments or inorganic pigments, such as carbon black or titanium white.

[0036] ≪Placement device≫ The disposing device 4 is a device that disposes the cover member 9 so as to cover the coating layer 71. In other words, the disposing device 4 is a device that performs step B in the manufacturing method of the sheet material. The cover member 9 is brought into close contact with the coating layer 71 so as to cover the coating layer 71, as shown in FIG.

[0037] The form of the cover member 9 is not particularly limited as long as it can cover the coating layer 71 by adhering to it. The cover member 9 in this example is a long resin film that can be rolled up. Unlike this example, when the substrate 70 is a short sheet, the cover member 9 may be a plate material that matches the size of the substrate 70. The plate material is, for example, glass or plastic. The separator separated from the tack paper may be reused as the cover member 9.

[0038] The placement device 4 is appropriately selected according to the form of the cover member 9. The placement device 4 in this example includes a feed drum 40 and a first roller 45. The feed drum 40 is a drum on which the cover member 9 of a resin film is wound. The feed drum 40 is disposed above the guide roller 22 of the conveying device 2. The lower end of the first roller 45 is disposed below the upper end of the guide roller 22. The first roller 45 guides the cover member 9 fed from the feed drum 40 in a direction approaching the substrate 70 at a position near the substrate 70. The cover member 9 guided by the first roller 45 is conveyed along the substrate 70, and as shown in FIG. 2, is brought into close contact with the coating layer 71 of the substrate 70 by the guide roller 22. The cover member 9 is pressed by the first roller 45 and a second roller 65 described later, so that the cover member 9 is maintained in a state of being superimposed on the substrate 70 in the region between the first roller 45 and the second roller 65. This region includes the irradiation region of the irradiation device 5 described later.

[0039] The cover member 9 is UV-transmissive. As described below, the cover member 9 is intended to shield the coating layer 71 from the atmosphere and prevent the coating layer 71 from being exposed to oxygen. Here, UV-transmissive in this specification means that UV is transmitted to an extent that the UV ink of this example can be practically cured. For example, a UV-transmissive cover member 9 is a cover member 9 that transmits 70% or more of the UV-A wavelength range of the UV irradiated from the irradiation device 5 described below.

[0040] 2, the cover member 9 of this example includes a base layer 90 and a release agent layer 91. The release agent layer 91 is formed on the surface of the base layer 90 that faces the coating layer 71. In this example, the release agent layer 91 is formed on the surface of the base layer 90 that faces downward when the cover member 9 is unwound from the delivery drum 40. The release agent layer 91 contains a release agent, which will be described later.

[0041] The base layer 90 is made of a resin that easily transmits ultraviolet rays and does not easily stretch. The base layer 90 in this example is made of, for example, PET resin. PET resin does not easily stretch, and can form a cover member 9 that is easily transported while adhering to the coating layer 71 at a certain pressure. Therefore, PET resin that easily transmits ultraviolet rays is suitable as a material for the base layer 90. In addition, the base layer 90 is not particularly limited as long as it is a material that transmits ultraviolet rays, and may be made of biaxially oriented polypropylene or the like. It is preferable that the base layer 90 is made of a material that does not easily transmit oxygen. However, since the curing of the UV ink is completed in a short time, it is acceptable for the base layer 90 to transmit oxygen to a certain extent.

[0042] The release agent layer 91 is a layer containing a release agent. The release agent is a substance that does not easily chemically bond with the UV ink when the UV ink is cured. Examples of the release agent include silicone resin, fluororesin, alkyd resin, long-chain alkyl resin, and various waxes. The release agent in this example is silicone resin. The release agent layer 91 is very thin, so it is easy to transmit ultraviolet light. Silicone resin is easy to obtain and inexpensive. Another advantage of silicone resin is that it is easy to form on the base layer 90. The release agent layer 91 may contain additives in addition to the release agent.

[0043] The thickness of the cover member 9 made of a resin film is, for example, 15 μm or more and 50 μm or less. A cover member 9 of 15 μm or more is easy to handle. A cover member 9 that is too thin is prone to wrinkles, and the cover members 9 are prone to stick to each other at the wrinkled parts. A cover member 9 of 50 μm or less is easy to bend. In this example, the cover member 9 is guided by the first roller 45 to be in close contact with the coating layer 71 of the substrate 70. A cover member 9 that is easy to bend is easy to be in close contact with the coating layer 71, and air bubbles are unlikely to be mixed between the coating layer 71 and the cover member 9. The thickness of the cover member 9 may be, for example, 20 μm or more and 45 μm or less, or 30 μm or more and 40 μm or less. Here, when the diameter of the feed drum 40 including the cover member 9 in the wrapped state is the same, the thinner the thickness of the cover member 9, the longer the length of the cover member 9 that can be wound around the feed drum 40. By increasing the length of the cover member 9 wound around the output drum 40, the frequency of replacement of the cover member 9 decreases, improving the productivity of the sheet material 7. It is preferable that the length of the cover member 9 wound around the output drum 40 and the length of the base material 70 wound around the output drum 20 are approximately the same. In this case, the timing of replacement of the output drum 20 and the output drum 40 can be synchronized.

[0044] Considering the function of the base layer 90 and the function of the release agent layer 91, the thickness of the base layer 90 is greater than the thickness of the release agent layer 91. For example, the proportion of the thickness of the cover member 9 made of a resin film that is occupied by the base layer 90 is 90% or more and 95% or less.

[0045] The cover member 9 is brought into close contact with the coating layer 71, thereby spreading the coating layer 71 thinly. Therefore, even if the amount of UV ink applied to the first surface 70s of the base material 70 is small, the coating layer 71 is likely to be formed uniformly over the entire surface of the first surface 70s. In other words, according to the configuration of this example, the amount of UV ink can be saved.

[0046] Furthermore, by the cover member 9 being in close contact with the coating layer 71, the surface of the coating layer 71 is likely to be smooth. If the surface of the coating layer 71 is smooth, the surface of the covering layer 75 formed by hardening the coating layer 71 will also be smooth. The covering layer 75 having a smooth surface has a gloss. Generally, in order to increase the gloss of the covering layer 75, it is necessary to increase the thickness of the coating layer 71. In the configuration of this example, the gloss of the covering layer 75 can be increased without increasing the thickness of the coating layer 71. The covering layer 75 functions as a protective layer that protects the first surface 70s.

[0047] ≪Irradiation device≫ The irradiation device 5 is a device that irradiates ultraviolet rays onto the integrated body of the base material 70 with the coating layer 71 and the cover member 9 that are arranged on the guide roller 22 of the conveying device 2. In other words, the irradiation device 5 is a device for carrying out step C in the manufacturing method of the sheet material. A known configuration can be used for the irradiation device 5. The ultraviolet rays in this example are ultraviolet rays having a wavelength range that contributes to the hardening of the UV ink that forms the coating layer 71. The ultraviolet rays in this example have peaks at 254 nm and 365 nm. The wavelength range of this ultraviolet light includes wavelengths of 40 nm before and after the main wavelength. The wavelength of 365 nm is the main wavelength.

[0048] The ultraviolet light irradiated downward from the irradiation device 5 passes through the cover member 9 and reaches the coating layer 71. The photopolymerization initiator in the coating layer 71 stimulated by the ultraviolet light generates radicals. These radicals polymerize the photopolymerization resin. The coating layer 71 is cured by this polymerization reaction, forming a coating layer 75. In the configuration of this example, since the guide roller 22 of the conveying device 2 is rotating, the sheet material 7 having the cured coating layer 75 in the irradiation area is sent out of the ultraviolet light irradiation area, and as the sheet material 7 is sent out, the base material 70 having the uncured coating layer 71 is sent into the irradiation area.

[0049] In the configuration of this example, the coating layer 71 is covered with the cover member 9 and is isolated from the atmosphere, so that the coating layer 71 is less likely to be exposed to oxygen. This reduces the amount of photopolymerization initiator that bonds with oxygen. By suppressing the bonding between the photopolymerization initiator and oxygen, the polymerization of the photopolymerization resin is promoted. In addition, the generation of odorous substances resulting from the bonding between the photopolymerization initiator and oxygen is suppressed.

[0050] <Removal device> The peeling device 6 is a device that peels off the cover member 9 from the coating layer 75. That is, the peeling device 6 is a device for performing the step D in the manufacturing method of the sheet material. The peeling device 6 in this example includes a winding drum 60 and a second roller 65. The winding drum 60 is disposed above the guide roller 22. The second roller 65 is disposed on the opposite side of the cover member 9 from the release agent layer 91. The lower end of the second roller 65 is disposed below the upper end of the guide roller 22. The winding drum 60 is disposed in a direction different from the direction in which the winding drum 29 of the conveying device 2 is disposed, as viewed from the guide roller 22. Therefore, the cover member 9 is guided by the second roller 65 in a direction away from the substrate 70, and is peeled off from the coating layer 75 formed on the substrate 70. The cover member 9 peeled off from the coating layer 75 is wound up on the winding drum 60.

[0051] According to the sheet material manufacturing method and sheet material manufacturing device 1 having the above configuration, as shown in Fig. 3, it is possible to manufacture a sheet material 7 in which a covering layer 75 is formed so as to cover a printed layer 70P on a base material 70. The covering layer 75 protects the printed layer 70P. In addition, the gloss of the covering layer 75 improves the appearance of the printed layer 70P.

[0052] The sheet material manufacturing method and sheet material manufacturing apparatus 1 of this embodiment do not require a configuration for introducing nitrogen into the ultraviolet ray irradiation area, and therefore do not require a configuration for exhausting nitrogen to prevent the introduced nitrogen from leaking into the work space. According to the configuration of this embodiment, which does not require the trouble of repairing or maintaining the configuration related to the introduction and exhaust of nitrogen, the sheet material 7 can be manufactured with good productivity.

[0053] <Modification> In the first embodiment, the coating layer 71 is formed on the upper surface of the substrate 70, and the cover member 9 is placed above the coating layer 71. Unlike the first embodiment, the coating layer 71 may be formed on the lower surface of the substrate 70, and the cover member 9 may be placed below the coating layer 71. In that case, the components of the sheet material manufacturing apparatus 1 are upside down compared to the arrangement illustrated in Fig. 1. Ultraviolet rays are irradiated upward.

[0054] <Test Example> In the test examples, the following sheet material No. 1 (sheet material 7) and sheet material No. 100 were prepared, and the influence of the presence or absence of the cover member 9 during irradiation with ultraviolet rays on the preparation of the sheet material was examined.

[0055] <Sample No. 1> The sheet material 7 of sample No. 1 was produced by the sheet material manufacturing apparatus 1 of embodiment 1. The base layer 90 of the cover member 9 used in producing this sample was PET resin, and the release agent contained in the release agent layer 91 was silicone resin. The thickness of the cover member 9, i.e., the total thickness of the base layer 90 and the release agent layer 91, was 38 μm.

[0056] <Sample No. 100> The sheet material of sample No. 100 was produced by irradiating ultraviolet rays without disposing a cover member 9 on the coating layer 71. The production conditions for sample No. 100 other than the cover member 9, such as the amount of UV ink applied to form the coating layer 71, were the same as those for sample No. 1.

[0057] <Peel test> After attaching cellophane tape of the same size to each of the coating layers 75 of sample No. 1 and sample No. 100, each cellophane tape was peeled off at an angle of 60° in one go. This test was carried out within 5 minutes after the irradiation of ultraviolet light. Next, the area of ​​the coating layer 75 attached to each cellophane tape was measured. The coating layer 75 was not attached to the adhesive surface of the cellophane tape peeled off from sample No. 1. This result means that the entire coating layer 71 was sufficiently cured. On the other hand, a part of the coating layer 75 was attached to the adhesive surface of the cellophane tape peeled off from sample No. 100. When the area of ​​the adhesive surface is taken as 100%, the area ratio of the coating layer 75 attached to the adhesive surface was about 5%. This result means that a part of the coating layer 71 was not sufficiently cured.

[0058] From this test result, it became clear that the entire coating layer 71 could be sufficiently cured by covering the coating layer 71 with the cover member 9. The reason why a part of the coating layer 71 in sample No. 100 was not sufficiently cured is presumably because oxygen was bonded to the photopolymerization initiator during irradiation with ultraviolet rays, resulting in an insufficient amount of photopolymerization initiator.

[0059] <Odor test> Each sample was cut to a specified size and then sealed in a sealed glass. The sealed glass was left at 25°C for 24 hours, and the odor inside the sealed glass was measured using an odor sensor. The odor sensor was an XP329 odor sensor manufactured by New Cosmos Electric Co., Ltd. This odor sensor displays the odor as a numerical value. The higher the numerical value, the stronger the odor. The odor values ​​of the odor sensor are shown in Table 1. The odor value is the actual measurement value minus the blank value. The blank value is the actual measurement value inside the empty sealed glass.

[0060] [Table 1]

[0061] As shown in Table 1, the odor value of sample No. 1 was about half that of sample No. 100. Therefore, it is considered that the sheet material 7 of sample No. 1 is unlikely to cause discomfort to users. Since the odor fades over time, even the sheet material of sample No. 100 can be stored for a certain period of time before shipping to reduce the odor at the time of shipping. However, the storage location and time of the sheet material increase the cost of the sheet material. Since the sheet material 7 of sample No. 1 can be shipped in a short period of time, the cost of the sheet material can be reduced.

[0062] <Gloss test> The gloss value of each sample was measured using a gloss meter. The gloss meter was a micro-tri-gloss gloss meter manufactured by BYK Co., Ltd. The gloss meter displays the gloss as a numerical value. The higher the numerical value, the glossier the sample is. The numerical values ​​of the gloss values ​​are shown in Table 2.

[0063] [Table 2]

[0064] As shown in Table 2, the gloss value of sample No. 1 was 30% or more higher than the gloss value of sample No. 100. It is presumed that the reason that the gloss value of sample No. 1 was high is that the surface of coating layer 71 was smoothed by adhering cover member 9 to coating layer 71. From these facts, it was found that, according to the configuration according to the embodiment, it is possible to increase the glossiness of the sheet material even if the amount of UV ink applied is small. [Explanation of symbols]

[0065] 1 Sheet material manufacturing equipment 2. Conveyor 20: delivery drum, 21, 22: guide rollers, 29: take-up drum 3 Coating equipment 30 Gravure Roll 4 Placement device 40 discharge drum, 45 first roller 5 Irradiation device 6 Peeling device 60 Winding drum, 65 Second roller 7 Sheet material 70 substrate, 70B base sheet, 70P printing layer, 70s first surface, 71 coating layer, 75 covering layer 9 Cover material 90 base layer, 91 release agent layer

Claims

1. A step A of applying a UV ink to a first surface of a sheet-like substrate to form a coating layer; A step B of adhering a cover member to the coating layer so as to cover the coating layer; A step C of irradiating the coating layer covered with the cover member with ultraviolet light to harden the coating layer, thereby forming a coating layer; and a step D, which is performed after the step C, of ​​peeling the cover member from the coating layer. The cover member is ultraviolet ray transparent, The surface of the cover member facing the coating layer contains a release agent. A method for manufacturing a sheet material.

2. the cover member is a flexible resin film, The resin film includes a base layer and a release agent layer, The method of claim 1 , wherein the release agent layer comprises the release agent.

3. The method for manufacturing a sheet material according to claim 2 , wherein the base layer is made of a polyethylene terephthalate resin.

4. The method for producing a sheet material according to claim 2 or 3, wherein the resin film has a thickness of 15 μm or more and 50 μm or less.

5. The method for producing a sheet material according to claim 1 or 2, wherein the release agent is a silicone resin.

6. The method for producing a sheet material according to claim 1 or 2, wherein in step A, the UV ink is applied to the first surface by gravure printing.

7. In the step B, the resin film taken up on the delivery drum by a first roller is guided in a direction approaching the substrate, and the resin film is brought into close contact with the substrate; The method for producing a sheet material according to claim 2 or 3, wherein in the step D, the resin film is guided in a direction away from the base material by a second roller, and the resin film is wound up onto a winding drum.

8. The substrate includes a base sheet and a printing layer printed on the base sheet, The method for producing a sheet material according to claim 1 or 2, wherein in step A, the coating layer covers the printed layer.

9. A conveying device that conveys a sheet-like base material; a coating device that coats a UV ink on a first surface of the substrate to form a coating layer on the first surface; a placement device for bringing a cover member into close contact with the coating layer so as to cover the coating layer; an irradiation device that irradiates the coating layer covered with the cover member with ultraviolet light to form a coating layer by hardening the coating layer; a peeling device that peels off the cover member from the coating layer, The cover member is ultraviolet ray transparent, The surface of the cover member facing the coating layer contains a release agent. Sheet material manufacturing equipment.

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