阅读说明：本技术 树脂片的制造方法 (Method for producing resin sheet ) 是由 高桥秀树 于 2019-06-17 设计创作，主要内容包括：提供能容易地制造具有造形物的树脂片的树脂片的制造方法。树脂片的制造方法包含：准备工序,准备树脂成形片,上述树脂成形片具备：基材；以及热膨胀层,其包含热膨胀材料,形成于上述基材的一个主面；热转换层形成工序,在上述树脂成形片的第1主面和与上述第1主面相反的一侧的第2主面中的至少一方形成将电磁波转换为热的热转换层；预备加热工序,将形成有上述热转换层的上述树脂成形片加热到比上述热膨胀材料开始膨胀的膨胀开始温度低的温度；以及正式加热工序,将上述电磁波照射到在上述预备加热工序中被加热的上述树脂成形片的上述热转换层而使上述热膨胀层膨胀,从而使上述基材变形而在上述树脂成形片形成造形物。(Provided is a method for producing a resin sheet, by which a resin sheet having a molded article can be easily produced. The method for producing a resin sheet comprises: a preparation step of preparing a resin molded sheet, the resin molded sheet including: a substrate; and a thermal expansion layer comprising a thermal expansion material and formed on one main surface of the base material; a heat conversion layer forming step of forming a heat conversion layer for converting electromagnetic waves into heat on at least one of a 1 st principal surface and a 2 nd principal surface on a side opposite to the 1 st principal surface of the resin molded sheet; a preliminary heating step of heating the resin molded sheet on which the heat conversion layer is formed to a temperature lower than an expansion start temperature at which the thermal expansion material starts to expand; and a main heating step of irradiating the electromagnetic wave to the heat conversion layer of the resin molded sheet heated in the preliminary heating step to expand the thermal expansion layer, thereby deforming the base material to form a molded article on the resin molded sheet.)

1. A method for producing a resin sheet, comprising:

a preparation step of preparing a resin molded sheet, the resin molded sheet including: a substrate; and a thermal expansion layer comprising a thermal expansion material and formed on one main surface of the base material;

a heat conversion layer forming step of forming a heat conversion layer for converting electromagnetic waves into heat on at least one of a 1 st principal surface and a 2 nd principal surface on a side opposite to the 1 st principal surface of the resin molded sheet;

a preliminary heating step of heating the resin molded sheet on which the heat conversion layer is formed to a temperature lower than an expansion start temperature at which the thermal expansion material starts to expand; and

and a main heating step of irradiating the electromagnetic wave to the heat conversion layer of the resin molded sheet heated in the preliminary heating step to expand the thermal expansion layer, thereby deforming the base material to form a molded article on the resin molded sheet.

2. The method of manufacturing a resin sheet according to claim 1,

in the preliminary heating step, the resin molded sheet on which the heat conversion layer is formed is heated to a temperature that is 25 ℃ or higher lower than the vicat softening temperature of the material constituting the base material.

3. The method of manufacturing a resin sheet according to claim 2,

in the preheating step, the resin molded sheet is heated by irradiating the electromagnetic wave.

4. The method of manufacturing a resin sheet according to claim 3,

in the primary heating step, the base material is deformed so that the height of the convex portion of the base material due to the deformation is larger than the amount of change in the thickness of the thermal expansion layer due to the expansion.

5. The method of manufacturing a resin sheet according to claim 4,

comprises a color ink layer forming step of forming a color ink layer on the 1 st main surface,

the heat conversion layer is formed on the 2 nd main surface.

6. The method of manufacturing a resin sheet according to claim 5,

in the color ink layer forming step, a color ink layer is formed on the 1 st main surface before the heat conversion layer forming step.

7. The method of manufacturing a resin sheet according to claim 2,

in the main heating step, the height of the convex portion of the base material due to the deformation of the base material is larger than the difference between the thickness of the thermally-expansible layer after expansion and the thickness of the thermally-expansible layer before expansion.

8. The method of manufacturing a resin sheet according to claim 7,

the thickness of the thermal expansion layer is the same as or smaller than the thickness of the base material.

9. The method of manufacturing a resin sheet according to claim 8,

in the preparation step, the thermal expansion layer is formed on the one main surface of the substrate.

10. The method of manufacturing a resin sheet according to claim 7,

in the preparation step, a peelable release layer is provided on at least one of the thermal expansion layer and the other main surface of the substrate,

in the heat conversion layer forming step, the heat conversion layer is formed on the release layer,

comprises a peeling step of peeling the release layer from the resin molded sheet on which the shaped article is formed.

11. A method for producing a resin sheet, comprising:

a preparation step of preparing a resin molded sheet, the resin molded sheet including: a substrate; and a thermal expansion layer comprising a thermal expansion material and formed on one main surface of the base material;

a heat conversion layer forming step of forming a heat conversion layer for converting electromagnetic waves into heat on at least one of a 1 st principal surface and a 2 nd principal surface on a side opposite to the 1 st principal surface of the resin molded sheet;

a first conveying step of heating the resin molded sheet on which the heat conversion layer is formed to a temperature lower than an expansion start temperature at which the thermal expansion material starts to expand, and conveying the resin molded sheet on which the heat conversion layer is formed; and

a 2 nd conveying step of irradiating the electromagnetic wave to the heat conversion layer of the resin molded sheet heated in the 1 st conveying step to expand the thermal expansion layer, thereby deforming the base material to form a molded article on the resin molded sheet, and conveying the resin molded sheet heated in the 1 st conveying step.

12. The method of manufacturing a resin sheet according to claim 11,

in the first conveying step 1, the heating temperature is a temperature at which the base material is softened and is lower than an expansion start temperature at which the thermal expansion material starts to expand.

13. The method of manufacturing a resin sheet according to claim 12,

in the first conveying step 1, the resin molded sheet on which the heat conversion layer is formed is heated to a temperature that is 25 ℃ or higher lower than the vicat softening temperature of the material constituting the base material.

14. The method of manufacturing a resin sheet according to claim 13,

in the 2 nd conveying step, the base material is deformed so that the height of the convex portion of the base material due to the deformation is larger than the amount of change in the thickness of the thermal expansion layer due to the expansion.

15. The method of manufacturing a resin sheet according to claim 14,

the thickness of the thermal expansion layer is the same as or smaller than the thickness of the base material.

16. The method of manufacturing a resin sheet according to claim 15,

in the preparation step, the thermal expansion layer is formed on the one main surface of the substrate.

17. The method of manufacturing a resin sheet according to claim 16,

in the preparation step, a peelable release layer is provided on at least one of the thermal expansion layer and the other main surface of the substrate,

in the heat conversion layer forming step, the heat conversion layer is formed on the release layer,

comprises a peeling step of peeling the release layer from the resin molded sheet on which the shaped article is formed.

18. The method of manufacturing a resin sheet according to claim 11,

the method includes a color ink layer forming step of forming a color ink layer on at least one of the 1 st main surface and the 2 nd main surface on the opposite side of the 1 st main surface.

Technical Field

The present invention relates to a method for producing a resin sheet using a thermally expandable material that expands upon heating.

Background

As an input unit of an electronic device, a membrane switch having a surface sheet is known. The surface sheet of the membrane switch is formed of, for example, resin, and is subjected to embossing. In the embossing process, various concave-convex patterns (shaped articles) are formed on the resin sheet by pressing with a die (for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

In the embossing process using a die, a die corresponding to the unevenness formed on the resin sheet is required. Therefore, there is a problem in that the manufacture of the mold requires cost and time.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a resin sheet, which can easily produce a resin sheet having a molded article.

Means for solving the problems

In order to achieve the above object, a method for producing a resin sheet according to claim 1 of the present invention includes:

a preparation step of preparing a resin molded sheet, the resin molded sheet including: a substrate; and a thermal expansion layer comprising a thermal expansion material and formed on one main surface of the base material;

a heat conversion layer forming step of forming a heat conversion layer for converting electromagnetic waves into heat on at least one of a 1 st principal surface and a 2 nd principal surface on a side opposite to the 1 st principal surface of the resin molded sheet;

a preliminary heating step of heating the resin molded sheet on which the heat conversion layer is formed to a temperature lower than an expansion start temperature at which the thermal expansion material starts to expand; and

and a main heating step of irradiating the electromagnetic wave to the heat conversion layer of the resin molded sheet heated in the preliminary heating step to expand the thermal expansion layer, thereby deforming the base material to form a molded article on the resin molded sheet.

In order to achieve the above object, a method for producing a resin sheet according to claim 2 of the present invention includes:

a preparation step of preparing a resin molded sheet, the resin molded sheet including: a substrate; and a thermal expansion layer comprising a thermal expansion material and formed on one main surface of the base material;

a heat conversion layer forming step of forming a heat conversion layer for converting electromagnetic waves into heat on at least one of a 1 st principal surface and a 2 nd principal surface on a side opposite to the 1 st principal surface of the resin molded sheet;

a first conveying step of heating the resin molded sheet on which the heat conversion layer is formed to a temperature lower than an expansion start temperature at which the thermal expansion material starts to expand, and conveying the resin molded sheet on which the heat conversion layer is formed; and

a 2 nd conveying step of irradiating the electromagnetic wave to the heat conversion layer of the resin molded sheet heated in the 1 st conveying step to expand the thermal expansion layer, thereby deforming the base material to form a molded article on the resin molded sheet, and conveying the resin molded sheet heated in the 1 st conveying step.

Effects of the invention

According to the present invention, the shaped object is formed by irradiation of electromagnetic waves without using a mold, and therefore a resin sheet having the shaped object can be easily manufactured.

Drawings

Fig. 1 is a schematic diagram showing a cross section of a resin molded sheet according to embodiment 1 of the present invention.

Fig. 2 is a flowchart illustrating a method for producing a resin molded sheet according to embodiment 1 of the present invention.

Fig. 3 is a schematic view of a resin sheet according to embodiment 1 of the present invention.

Fig. 4 is a sectional view of the resin sheet shown in fig. 3 taken along line a-a.

Fig. 5 is a schematic view showing an expansion device according to embodiment 1 of the present invention.

Fig. 6 is a flowchart illustrating a method for manufacturing a resin sheet according to embodiment 1 of the present invention.

Fig. 7 is a schematic diagram showing a cross section of the resin molded sheet having the heat conversion layer formed thereon according to embodiment 1 of the present invention.

Fig. 8 is a schematic diagram showing a cross section of a resin sheet according to embodiment 2 of the present invention.

Fig. 9 is a flowchart illustrating a method for manufacturing a resin sheet according to embodiment 2 of the present invention.

Fig. 10 is a schematic view showing a cross section of a resin-molded sheet formed with a color ink layer according to embodiment 2 of the present invention.

Fig. 11 is a schematic diagram showing a cross section of a resin molded sheet having a heat conversion layer formed thereon according to embodiment 2 of the present invention.

Fig. 12 is a schematic diagram showing a cross section of a resin sheet according to embodiment 3 of the present invention.

Fig. 13 is a schematic diagram showing a cross section of a resin molded sheet according to embodiment 3 of the present invention.

Fig. 14 is a flowchart showing a method for producing a resin molded sheet according to embodiment 3 of the present invention.

Fig. 15 is a flowchart illustrating a method for manufacturing a resin sheet according to embodiment 3 of the present invention.

Fig. 16 is a schematic diagram showing a cross section of a resin molded sheet having a heat conversion layer formed thereon according to embodiment 3 of the present invention.

Fig. 17 is a schematic diagram showing a cross section of a resin molded sheet in which a 1 st convex portion is formed according to embodiment 3 of the present invention.

Fig. 18 is a schematic diagram showing a cross section of a resin sheet according to embodiment 4 of the present invention.

Fig. 19 is a flowchart showing a method for producing a resin sheet according to embodiment 4 of the present invention.

Fig. 20 is a schematic diagram showing a cross section of a resin molded sheet having a heat conversion layer formed thereon according to embodiment 4 of the present invention.

Detailed Description

Hereinafter, a method for producing a resin sheet according to an embodiment of the present invention will be described with reference to the drawings.

< embodiment 1 >

In the present embodiment, the resin sheet 100 having the 1 st projection 120 as the shaped object is manufactured from the resin molded sheet 10. The resin sheet 100 is used as a dot print, a surface sheet of a membrane switch, or the like. In the present specification, the term "shaped article" is not limited to a convex article such as the 1 st convex part 120, and includes an article having a concave shape, a geometric shape, and the like. In addition, the shaped object can also be formed into characters, patterns, decorations, and the like. Here, "decoration" refers to an object that evokes an aesthetic sense by visual and/or tactile sense. The "shape (or form)" is not limited to simply forming a shaped object, and includes a concept of adding a decorative decoration or forming a decorative decoration.

(resin molded sheet)

First, the resin molded sheet 10 used for manufacturing the resin sheet 100 will be described with reference to fig. 1 and 2. As shown in fig. 1, the resin molded sheet 10 includes a base 20 and a thermally-expansible layer 30 formed on one main surface 22 of the base 20.

The base material 20 of the resin molded sheet 10 includes: forming the one main surface 22 of the thermal expansion layer 30; and another main surface 24 on the opposite side of the main surface 22. The substrate 20 supports the thermal expansion layer 30. The substrate 20 is formed in a sheet shape, for example. Examples of the material constituting the substrate 20 include thermoplastic resins such as polyolefin resins (polyethylene (PE), polypropylene (PP), and the like), and polyester resins (polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and the like).

The kind of material constituting the base material 20 and the thickness of the base material 20 are set according to the ease of deformation of the base material 20 occurring in the production of the resin sheet 100, the strength of the base material 20 after deformation, and the like. The type of material constituting the base material 20 and the thickness of the base material 20 are also selected according to the use of the resin sheet 100. For example, when the resin sheet 100 is used as a surface sheet of a membrane switch, the kind of material constituting the base material 20 and the thickness of the base material 20 are selected so as to have an elastic force that returns to an original shape after being deformed by pressing.

The thermally-expansible layer 30 of the resin-molded sheet 10 is provided on the main surface 22 of the base material 20. The thermal expansion layer 30 is a layer that expands to a size corresponding to a heating temperature, a heating time, and the like. The thermal expansion layer 30 includes: a binder (binder) not shown; and a thermal expansion material, not shown, dispersed in the adhesive. The binder of the thermal expansion layer 30 is any thermoplastic resin such as a vinyl acetate polymer and an acrylic polymer. The thermally expandable material is, for example, a thermally expandable microcapsule, and is a material that expands when heated to a predetermined temperature or higher. The thermally expandable material is expanded by heating to 80 to 120 ℃. Hereinafter, the predetermined temperature at which the thermal expansion material starts to expand is referred to as an expansion start temperature.

The heat-expandable microcapsule is a microcapsule in which a foaming agent containing propane, butane, or other low-boiling point substance is enclosed in a shell made of a thermoplastic resin. The shell of the thermally expandable microcapsule is formed of a thermoplastic resin such as polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, polyacrylonitrile, polybutadiene, or a copolymer thereof. When the thermally expandable microcapsule is heated to the expansion start temperature or higher, the shell softens and the foaming agent vaporizes, and the shell expands into a balloon shape by the pressure of the vaporization of the foaming agent. The thermally expandable microcapsules expand to about 5 times the particle size before expansion. The average particle diameter of the heat-expandable microcapsules is, for example, 5 to 50 μm.

The thicknesses of the adhesive agent constituting the thermally-expansible layer 30, the thermally-expansible microcapsules, and the thermally-expansible layer 30 are selected so that the base material 20 is deformed into a desired shape in the production of the resin sheet 100. In the present embodiment, as described later, the height of the 2 nd convex portion 26 of the base material 20 formed by deformation of the base material 20 is larger than the amount of change in the thickness of the thermal expansion layer 30 due to expansion, and therefore the thickness of the thermal expansion layer 30 is preferably the same as the thickness of the base material 20 or smaller than the thickness of the base material 20.

In the present embodiment, the thermal expansion layer 30 is formed on the main surface 22 of the substrate 20. Therefore, one of the surface 32 of the thermal expansion layer 30 opposite to the surface in contact with the main surface 22 and the main surface 24 of the substrate 20 is the 1 st main surface of the resin molded sheet 10, and the other is the 2 nd main surface of the resin molded sheet 10 opposite to the 1 st main surface. In the present embodiment, for ease of understanding, the surface 32 of the thermal expansion layer 30 is defined as the 1 st main surface 32 of the resin molded sheet 10, and the main surface 24 of the base 20 is defined as the 2 nd main surface 24 of the resin molded sheet 10.

Next, a method for producing the resin molded sheet 10 will be described. Fig. 2 is a flowchart illustrating a method of manufacturing the resin molded sheet 10. The method for producing the resin molded sheet 10 includes a step of forming the thermally expanded layer 30 on the one principal surface 22 of the base 20 (step S11).

First, the base material 20 and a coating liquid for forming the thermal expansion layer 30 are prepared. The base material 20 may be in the form of a roll or may be cut into a sheet in advance. The coating liquid for forming the thermally-expansible layer 30 is prepared by mixing a binder and thermally-expansible microcapsules.

In the step of forming the heat-expandable layer 30 (step S11), the coating liquid is applied to the one main surface 22 of the base material 20 using the coating apparatus (step S12). The coating apparatus is a bar coater, roll coater, spray coater, or the like. Next, the coating liquid applied to the main surface 22 of the substrate 20 is dried (step S13). Thereby, the thermal expansion layer 30 is formed on the one main surface 22 of the substrate 20. The resin molded sheet 10 is produced in the above manner. In order to obtain a predetermined thickness of the thermal expansion layer 30, the application of the coating liquid (step S12) and the drying of the coating liquid (step S13) may be repeated. In the case where the thermal expansion layer 30 is formed on the roll-shaped base material 20, the base material 20 on which the thermal expansion layer 30 is formed may be cut to a desired size.

(resin sheet)

Next, a resin sheet 100 produced from the resin molded sheet 10 will be described with reference to fig. 3 and 4. As shown in fig. 3, the resin sheet 100 is a sheet having a plurality of 1 st projections 120. As shown in fig. 4, the resin sheet 100 includes: a substrate 20; a thermally-expansible layer 30 formed on one main surface 22 of the substrate 20; and a heat conversion layer 110 formed in a predetermined pattern on the other main surface 24 of the substrate 20.

The resin sheet 100 has the 1 st projection 120 of a convex shape as a shaped object. The 1 st projection 120 is formed according to a predetermined pattern of the heat conversion layer 110. In addition, the 1 st convex part 120 includes: a 2 nd convex portion 26 formed on the base material 20; and a 3 rd convex portion 34 formed on the thermal expansion layer 30.

The heat conversion layer 110 of the resin sheet 100 converts the irradiated electromagnetic waves into heat and emits the converted heat. The heat conversion layer 110 heats the base material 20 and the thermal expansion layer 30 by the emitted heat. Specifically, the heat conversion layer 110 heats the substrate 20 to a temperature lower than the expansion start temperature, and softens the substrate. Next, the thermal conversion layer 110 heats the thermal expansion layer 30 to the expansion start temperature or higher. The thermal expansion layer 30 expands to a size corresponding to a heating temperature, a heating time, and the like. The heat conversion layer 110 converts electromagnetic waves into heat more rapidly than the other portions of the resin sheet 100, and therefore only the region near the heat conversion layer 110 can be selectively heated. Therefore, the portion corresponding to the pattern of the heat conversion layer 110 of the resin molded sheet 10 is selectively heated.

The heat conversion layer 110 includes a heat conversion material that converts the absorbed electromagnetic waves into heat. The heat conversion material is carbon black, a hexaboride metal compound, a tungsten oxide compound, or the like, which is a carbon molecule. For example, carbon black absorbs visible light, infrared light, and the like and converts them into heat. Further, the metal hexaboride and the tungsten oxide compound absorb near infrared rays and convert them into heat. Among the hexaboride metal compound and the tungsten oxide compound, lanthanum hexaboride (LaB) is preferable because of its high absorptivity in the near infrared region and high transmittance in the visible light region₆) And cesium tungsten oxide (Cs)₂WO₄)。

The base material 20 and the thermally-expansible layer 30 of the resin sheet 100 are configured in the same manner as the base material 20 and the thermally-expansible layer 30 of the resin molded sheet 10. The 2 nd convex portion 26 of the base material 20 and the 3 rd convex portion 34 of the thermal expansion layer 30, that is, the 1 st convex portion 120 of the resin sheet 100 are formed by deforming the base material 20 in a manufacturing process of the resin sheet 100 described later. In the present embodiment, the height H of the 2 nd convex portion 26 of the base material 20 due to deformation is larger than the difference between the thickness d1 of the expanded portion of the thermal expansion layer 30 and the thickness d2 of the thermal expansion layer 30 before expansion. The difference between the thickness D1 of the expanded portion of the thermal expansion layer 30 and the thickness D2 of the thermal expansion layer 30 before expansion is defined as the amount of change Δ D in the thickness of the thermal expansion layer 30 due to expansion. In fig. 4, the change amount Δ D is the difference between the thickness D1 of the thermal expansion layer 30 in the 3 rd convex portion 34 and the thickness D2 of the thermal expansion layer 30 other than the 3 rd convex portion 34.

(method for producing resin sheet)

Next, a method for producing the resin sheet 100 will be described. In the present embodiment, the resin sheet 100 having the 1 st projection 120 as the shaped object is manufactured from the resin molded sheet 10 in a sheet shape (for example, a paper size for a 4).

First, an apparatus used in the method for producing the resin sheet 100 will be described. In the heat conversion layer forming step (step S30) described later, a printing apparatus (not shown) is used to print the ink containing the heat conversion material onto the resin molded sheet 10. The printing device is, for example, an inkjet printer.

The expansion device 300 is used in the preliminary heating step (step S40) and the main heating step (step S50) described later. As shown in fig. 5, the expansion device 300 includes: a tray 310 on which the resin molded sheet 10 is placed; an irradiation unit 320 for irradiating the resin molded sheet 10 with an electromagnetic wave; and a movement mechanism, not shown, for moving the irradiation unit 320. Hereinafter, the vertical direction of fig. 5 will be described as vertical direction.

The tray 310 of the inflation device 300 arranges the resin molded sheet 10 placed thereon at a predetermined position in the inflation device 300.

The irradiation unit 320 of the inflation device 300 irradiates electromagnetic waves to the resin molded sheet 10 placed on the tray 310. The irradiation unit 320 irradiates the resin molded sheet 10 with electromagnetic waves while moving above the resin molded sheet 10 by the moving mechanism. The irradiation unit 320 includes a cover 321, a lamp heater 322, a reflecting plate 323, and a fan 324.

The cover 321 of the irradiation part 320 houses the lamp heater 322, the reflecting plate 323, and the fan 324. The lamp heater 322 of the irradiation part 320 includes, for example, a straight-tube-shaped halogen lamp. The lamp heater 322 irradiates electromagnetic waves in the near infrared region (wavelength of 750nm to 1400nm), the visible light region (wavelength of 380nm to 750nm), the mid infrared region (wavelength of 1400nm to 4000nm), and the like to the resin molded sheet 10. The reflecting plate 323 is a reflecting plate that reflects the electromagnetic waves irradiated from the lamp heater 322 toward the resin molded sheet 10. The fan 324 sends air into the cover 321, cooling the lamp heater 322 and the reflection plate 323.

A method for producing the resin sheet 100 will be described with reference to fig. 6 and 7. Fig. 6 is a flowchart illustrating a method of manufacturing the resin sheet 100. The method for producing the resin sheet 100 includes: a preparation step (step S20) of preparing a resin molded sheet 10; a thermal conversion layer forming step (step S30) of forming the thermal conversion layer 110; a preliminary heating step (step S40) of heating the resin molded sheet 10 to a temperature lower than the expansion start temperature of the thermal expansion material; and a main heating step (step S50) of forming the 1 st projection 120 by irradiating electromagnetic waves to expand the thermal expansion layer 30.

In the preparation step (step S20), first, the resin molded sheet 10 is prepared. The resin molded sheet 10 is manufactured by the above-described method for manufacturing the resin molded sheet 10 (step S11 to step S13), for example. Further, an ink containing a heat conversion material is prepared. The ink containing the heat conversion material is, for example, an ink containing carbon black.

Next, the ink containing carbon black is printed in a predetermined pattern corresponding to the pattern of the 1 st convex portion 120 on the main surface 24 of the base material 20 (i.e., the 2 nd main surface 24 of the resin molded sheet 10) by the printing device, and the heat conversion layer 110 is formed on the 2 nd main surface 24 of the resin molded sheet 10 as shown in fig. 7 (heat conversion layer forming step: step S30). Here, since the amount of heat emitted from the heat conversion layer 110 depends on the concentration of carbon black and the energy per unit area and unit time of the electromagnetic wave irradiated to the heat conversion layer 110, the amount of change Δ D in the thickness of the thermal expansion layer 30 and the height H of the 2 nd convex portion 26 of the substrate 20 can be controlled by the density of the ink containing carbon black and the energy per unit area and unit time of the irradiated electromagnetic wave. The height of the 1 st projection 120 of the resin sheet 100 can be controlled by controlling the amount of change Δ D in the thickness of the thermal expansion layer 30 and the height H of the 2 nd projection 26 of the base 20. The energy per unit area and unit time with respect to the electromagnetic wave irradiated to the heat conversion layer 110 is described later.

Next, returning to fig. 6, the resin molded sheet 10 on which the heat conversion layer 110 is formed (hereinafter, referred to as the resin molded sheet 10 with a heat conversion layer) is set in the tray 310 of the expansion device 300. Then, the electromagnetic wave is irradiated from the irradiation part 320 of the expansion device 300 to the resin molded sheet with heat conversion layer 10, thereby heating the resin molded sheet with heat conversion layer 10 to a temperature lower than the expansion start temperature (preliminary heating step: step S40).

Specifically, as the movement of the irradiation part 320 for the 1 st time, the irradiation part 320 is moved in a state where the electromagnetic wave is irradiated to the resin molded sheet 10 with the heat conversion layer. The temperature of the resin molded sheet with heat conversion layer 10 can be adjusted by controlling the energy per unit area and unit time of the electromagnetic wave irradiated to the resin molded sheet with heat conversion layer 10 by controlling the moving speed of the irradiation unit 320, the intensity of the electromagnetic wave, and the like.

In the present embodiment, the resin molded sheet with heat transfer layer 10 is heated to a temperature lower than the expansion start temperature, and thus the base material 20 is softened. Therefore, in the main heating step (step S50), the height of the 1 st convex portion 120 of the resin sheet 100 can be made higher. Further, by softening the base material 20, the 1 st projecting portion 120 can be formed more finely.

When the resin molded sheet with a heat conversion layer 10 is heated to the expansion start temperature or higher, the thermal expansion layer 30 expands before the main heating step (step S50), and therefore the resin molded sheet with a heat conversion layer 10 is heated to a temperature lower than the expansion start temperature. In the main heating step (step S50), the resin molded sheet 10 with the heat conversion layer is preferably heated to a temperature lower than the expansion start temperature by 5 ℃. In order to sufficiently soften the base material 20, the resin molded sheet 10 with the heat conversion layer is preferably heated to a temperature that is 25 ℃ or higher lower than the vicat softening temperature of the material constituting the base material 20. The temperature of the region of the substrate 20 where the heat conversion layer 110 is provided is preferably higher than the temperature of the region where the heat conversion layer 110 is not provided. This can suppress softening of the region where the heat conversion layer 110 of the base material 20 is not provided, and the 1 st projecting portion 120 can be formed in the main heating step (step S50). The Vicat softening temperature is measured, for example, in accordance with JIS K7206 (method B50), and is generally 70 to 80 ℃ for PE and 180 to 190 ℃ for PBT.

Finally, the irradiation section 320 irradiates an electromagnetic wave to the heat conversion layer 110 of the resin molded sheet with heat conversion layer 10 heated to a temperature lower than the expansion start temperature in the preliminary heating step (step S40) to expand the thermal expansion layer 30, thereby deforming the base material 20 and forming the 1 st projection 120 in the resin molded sheet with heat conversion layer 10 (main heating step: step S50). That is, in the present embodiment, the heating is performed in 2 steps, i.e., the preliminary heating step (step S40) and the main heating step (step S50).

Specifically, as the 2 nd irradiation unit 320 moves, the irradiation unit 320 is moved in a state where the electromagnetic wave is irradiated to the heat conversion layer 110. Here, the energy per unit area and unit time of the electromagnetic wave irradiated to the heat conversion layer 110 is controlled so that the thermal expansion layer 30 is heated to the expansion start temperature or more by the heat emitted from the heat conversion layer 110. Thereby, the portion of the thermal expansion layer 30 corresponding to the pattern of the thermal conversion layer 110 selectively expands. Further, the energy per unit area and unit time of the electromagnetic wave irradiated to the thermal expansion layer 30 can be controlled by the moving speed of the irradiation portion 320, the intensity of the electromagnetic wave irradiated from the irradiation portion 320, and the like.

When the thermal expansion layer 30 formed on the main surface 22 of the substrate 20 expands, a force perpendicular to the main surfaces 22 and 24 is applied to the substrate 20 from the main surface 24 toward the main surface 22. Since the base material 20 is softened in the preliminary heating step (step 40) and further softened by the heat released from the heat conversion layer 110, it is deformed toward the thermal expansion layer 30 by a vertical force applied by the expansion of the thermal expansion layer 30. The 2 nd projection 26 is formed on the base material 20 and the 3 rd projection 34 is formed on the thermal expansion layer 30 by the deformation of the base material 20. The 1 st projection 120 is formed on the resin molded sheet with heat transfer layer 10. As described above, the height of the 1 st protrusion 120 can be controlled by the density of the carbon black-containing ink constituting the heat conversion layer 110 and the energy per unit area and unit time of the electromagnetic wave irradiated to the heat conversion layer 110.

In the present embodiment, since the base material 20 is softened in the preliminary heating step (step S40), the height of the 1 st convex portion 120 of the resin sheet 100 can be further increased. Further, the 1 st projection 120 can be formed more finely.

As described above, the resin sheet 100 having the 1 st projection 120 as the shaped object can be manufactured. In the present embodiment, the resin sheet 100 can be easily manufactured because the 1 st convex portion 120 is formed by irradiation of electromagnetic waves without using a mold. Further, before the thermal expansion layer 30 is expanded by irradiation with electromagnetic waves to form the 1 st convex portion 120, the resin molded sheet 10 with a thermal conversion layer is heated to a temperature lower than the expansion starting temperature to soften the base material 20, so that the height of the 1 st convex portion 120 can be made higher and a finer 1 st convex portion 120 can be formed.

< embodiment 2 >

Although the thermal expansion layer 30 and the thermal conversion layer 110 are formed on the base 20 in the production of the resin sheet 100 according to embodiment 1, other layers may be formed in the production of the resin sheet 100.

In the present embodiment, as shown in fig. 8, the resin sheet 100 includes a base 20, a thermal expansion layer 30, a thermal conversion layer 110, and a color ink (color ink) layer 130. In addition, the resin sheet 100 has the 1 st projection 120 as a shaped object. The configurations of the substrate 20, the thermal expansion layer 30, and the heat conversion layer 110 are the same as those of the substrate 20, the thermal expansion layer 30, and the heat conversion layer 110 of embodiment 1. Here, a method for manufacturing the color ink layer 130 and the resin sheet 100 having the color ink layer 130 will be described. In addition, similarly to embodiment 1, the surface 32 of the thermal expansion layer 30 is the 1 st main surface 32 of the resin molded sheet 10, and the main surface 24 of the base 20 is the 2 nd main surface 24 of the resin molded sheet 10.

First, the color ink layer 130 is explained. The color ink layer 130 is disposed on the face 32 of the thermal expansion layer 30. By providing the color ink layer 130 with a predetermined pattern, a color image such as characters, figures, and patterns can be formed on the resin sheet 100.

The color ink layer 130 includes 4 color inks of cyan C, magenta M, yellow Y, and black K. It is preferable that the ink of black K does not contain carbon so that the electromagnetic wave is converted into heat and the converted heat is not emitted.

Next, a method for producing the resin sheet 100 including the color ink layer 130 according to the present embodiment will be described with reference to fig. 9 to 11. Fig. 9 is a flowchart illustrating a method for manufacturing the resin sheet 100 of the present embodiment. The method for producing the resin sheet 100 of the present embodiment includes a preparation step (step S20), a color ink layer forming step (step S25) of forming the color ink layer 130, a heat conversion layer forming step (step S30), a preliminary heating step (step S40), and a main heating step (step S50).

In the preparation step (step S20), the resin molded sheet 10 is prepared in the same manner as in the method for producing the resin sheet 100 of embodiment 1. Then, ink containing a heat conversion material and 4-color ink of CMYK are prepared.

Next, 4 colors of CMYK ink are printed on the thermal expansion layer 30 in a predetermined pattern by a printing apparatus, and as shown in fig. 10, a color ink layer 130 is formed in a predetermined pattern on the surface 32 of the thermal expansion layer 30 (i.e., the 1 st main surface 32 of the resin molded sheet 10) (color ink layer forming step: step S25).

Next, returning to fig. 9, the ink containing the heat conversion material is printed in a predetermined pattern on the 2 nd main surface 24 of the base material 20 of the resin molded sheet 10 on which the color ink layer 130 is formed (i.e., the 2 nd main surface 24 of the resin molded sheet 10), and the heat conversion layer 110 is formed on the 2 nd main surface 24 of the resin molded sheet 10 as shown in fig. 11 (heat conversion layer forming step: step S30). The heat conversion layer forming step (step S30) of the present embodiment is the same as the heat conversion layer forming step (step S30) of embodiment 1, except that the color ink layer 130 is formed.

Next, returning to fig. 9, the preliminary heating step (step S40) and the main heating step (step S50) are performed. The preliminary heating step (step S40) and the main heating step (step S50) of the present embodiment are the same as the preliminary heating step (step S40) and the main heating step (step S50) of embodiment 1, except that the color ink layer 130 is formed.

As described above, the resin sheet 100 having the 1 st projection 120 as a molded article and the color ink layer 130 can be manufactured. In the present embodiment, as in embodiment 1, the resin sheet 100 can be easily manufactured because the 1 st convex portion 120 is formed by irradiation of electromagnetic waves without using a mold. Further, since the base material 20 is softened before the thermal expansion layer 30 is expanded to form the 1 st convex portion 120, the height of the 1 st convex portion 120 can be made higher, and the 1 st convex portion 120 can be made finer. The color ink layer forming step (step S25) may be performed after the heat conversion layer forming step (step S30) of embodiment 1.

< embodiment 3 >