JP7251571B2 - Method for manufacturing thermally expandable sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a thermally expandable sheet.

2. Description of the Related Art Conventionally, thermally expandable sheets are known in which a thermally expandable layer containing a thermally expandable material that foams and expands according to the amount of heat absorbed is formed on one surface of a base sheet. A photothermal conversion layer that converts light into heat is formed on this thermally expandable sheet, and by irradiating the photothermal conversion layer with light, the thermal expansion layer can be partially or wholly expanded. Also known is a method of forming a three-dimensional object (three-dimensional image) on a thermally expandable sheet by changing the shape of the photothermal conversion layer (see, for example, Patent Documents 1 and 2).

JP-A-64-28660 Japanese Patent Application Laid-Open No. 2001-150812

However, in a thermally expandable sheet in which a thermally expandable layer is formed directly on a substrate, the thermally expandable layer may separate from the substrate when the thermally expandable layer is foamed and expanded. Peeling often occurs particularly when a resin sheet (film) is used as the base material.

Accordingly, there is a demand for a thermally expandable sheet and a method for producing a thermally expandable sheet that can prevent the thermally expandable layer from peeling off from the substrate when the thermally expandable layer is expanded.

The present invention has been made in view of the above circumstances, and provides a method for producing a thermally expandable sheet capable of suppressing separation of a thermally expandable layer from a substrate when the thermally expandable layer is expanded. intended to provide

In order to achieve the above object, the method for producing a thermally expandable sheet according to the present invention comprises:
A step of forming an anchor layer by applying a predetermined ink onto one surface of a substrate, which is a film made of resin;
forming a thermal expansion layer on the anchor layer;
forming a first ink-receiving layer by applying an ink having the same component composition as the ink on the outermost surface of the substrate on the side where the thermal expansion layer is provided;
including
The ink contains one or more resins selected from the group consisting of polyvinyl alcohol (PVA), polyurethane, and acrylic.
It is characterized by

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the thermally expandable sheet which can suppress peeling of a thermally expandable layer from a base material when a thermally expandable layer is expand|swelled can be provided .

1 is a cross-sectional view showing an overview of a thermally expandable sheet according to Embodiment 1. FIG. 1 is a cross-sectional view showing an overview of a method for manufacturing a thermally expandable sheet according to Embodiment 1. FIG. 1 is a diagram showing an overview of a corona treatment apparatus according to Embodiment 1; FIG. 2 is a diagram showing an overview of a stereoscopic image forming unit according to Embodiment 1; FIG. 4 is a flow chart showing a stereoscopic image forming process according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view showing an outline of a stereoscopic image forming process according to Embodiment 1; (a) is a graph showing the relationship between the black density of the photothermal conversion layer and the amount of protrusion of the thermal expansion layer when heated at the first level. (b) is a graph showing the relationship between the black density of the photothermal conversion layer and the amount of protrusion of the thermal expansion layer when heated at the second level. FIG. 5 is a cross-sectional view showing an outline of a thermally expandable sheet according to Embodiment 2; FIG. 4 is a cross-sectional view showing an outline of a method for manufacturing a thermally expandable sheet according to Embodiment 2; FIG. 10 is a cross-sectional view showing an overview of a thermally expandable sheet according to Embodiment 3; FIG. 10 is a cross-sectional view showing an outline of a method for manufacturing a thermally expandable sheet according to Embodiment 3; FIG. 10 is a cross-sectional view showing an overview of a thermally expandable sheet according to a modification; FIG. 10 is a cross-sectional view showing an overview of a thermally expandable sheet according to a modification;

Hereinafter, a thermally expandable sheet and a method for manufacturing the thermally expandable sheet according to embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The thermally expandable sheet 10 according to Embodiment 1 comprises a substrate 11, an anchor layer 12, a thermally expandable layer 13, a first ink-receiving layer 14 and a second ink-receiving layer 15, as shown in FIG. Further, as will be described later in detail, the thermally expandable sheet 10 is subjected to printing by a three-dimensional image forming system 70 whose outline is shown in FIGS. image) is formed.

The base material 11 is a sheet-like member that supports the thermal expansion layer 13 and the like. As the substrate 11, a generally used resin sheet-like member (film) can be appropriately selected and used. As the base material 11, a sheet-like material containing polyolefin resin such as polyethylene or polypropylene, polyester resin, polyamide resin such as nylon, polyvinyl chloride resin, polyimide resin, silicone resin, or the like is used. be able to. In addition, when the thermal expansion layer 13 is wholly or partially expanded by foaming, the base material 11 does not rise on the opposite side of the base material 11 (lower side shown in FIG. 1), wrinkles, or It has a strength that does not cause large waves. In addition, it has enough heat resistance to withstand heating when foaming the thermal expansion layer. Furthermore, the base material 11 may have stretchability in addition to the strength and heat resistance described above.

As will be described later, in this embodiment, a sheet-like member in which an ink receiving layer and a sheet are integrally formed can also be used as the substrate 11 . Specifically, the thermally expandable sheet 10 is produced by using a sheet-like member having an ink-receiving layer on the uppermost surface (outermost surface) of the sheet (film) formed from the material described above as the base material 11 . can also When such a sheet is used as the substrate 11 , the ink-receiving layer provided on the substrate 11 is used as the second ink-receiving layer 15 .

The anchor layer 12 is provided on one surface (upper surface shown in FIG. 1) of the base material 11 , and the thermal expansion layer 13 is provided on the anchor layer 12 . The anchor layer 12 is a layer having good adhesion to both the substrate 11 and the thermal expansion layer 13 . In addition, the anchor layer 12 has the function of increasing the adhesive force between the base material 11 and the thermal expansion layer 13 . By providing the anchor layer 12, it is possible to prevent the lower surface of the thermal expansion layer 13 from peeling off from the substrate 11 when the thermal expansion layer 13 is foamed and expanded.

Anchor layer 12 is a layer containing a material having good adhesion to base material 11 and thermal expansion layer 13 . Specifically, the anchor layer 12 contains at least one resin selected from the group consisting of polyester, acrylic, polyurethane, or copolymers thereof. For example, the resin contained in the anchor layer 12 may contain only a polyester-based resin, or may contain a polyester-based resin and a polyurethane-based resin. Moreover, the resin contained in the anchor layer 12 may be modified with a modifying agent. In particular, in the present embodiment, the anchor layer 12 preferably contains a polyester/acrylic/urethane composite resin. Although it is not limited to this, examples of the aqueous dispersion containing the polyester/acrylic/urethane composite resin include “WAC-17XC” manufactured by Takamatsu Yushi Co., Ltd. and the like.

Moreover, in the present embodiment, the anchor layer 12 is not limited to being formed from the above materials, and includes a surface modification layer formed by subjecting the surface of the substrate 11 to corona treatment. Specifically, the surface modified layer is formed using a corona treatment apparatus 60 shown in FIG. 3, which will be described later. This surface-modified layer is a layer having improved adhesion to the thermal expansion layer 13 as compared to the unmodified substrate 11 . Since the surface-modified layer adheres well to the thermal expansion layer 13 , it is possible to suppress peeling of the thermal expansion layer 13 when the thermal expansion layer 13 expands.

The thermal expansion layer 13 is formed on the anchor layer 12 provided on one surface (upper surface in FIG. 1) of the base material 11 and in contact with the anchor layer 12 . The thermal expansion layer 13 is a layer that expands to a size corresponding to heating temperature and heating time, and has a plurality of thermally expandable materials (thermally expandable microcapsules, microcapsules) dispersed in a binder. Further, as described later in detail, in the present embodiment, a photothermal conversion layer is provided on the first ink receiving layer 14 provided on the upper surface (front surface) of the substrate 11 and/or on the lower surface (rear surface) of the substrate 11. is formed and irradiated with light to generate heat in the region provided with the photothermal conversion layer. Since the thermal expansion layer 13 expands by absorbing the heat generated in the front and/or back light-to-heat conversion layers, it is possible to selectively expand only specific regions of the thermal expansion sheet.

As the binder, a thermoplastic resin such as a vinyl acetate polymer or an acrylic polymer is used. Thermally expandable microcapsules contain propane, butane, and other low-boiling vaporizable substances in shells made of thermoplastic resin. The shell is made of thermoplastic resin such as polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, polyacrylonitrile, polybutadiene, or copolymers thereof. The average particle size of the thermally expandable microcapsules is about 5-50 μm. When the microcapsules are heated to a temperature higher than the thermal expansion initiation temperature, the macromolecular shells made of resin are softened, the low-boiling-point vaporizable substance contained therein is vaporized, and the pressure causes the capsules to expand. Depending on the characteristics of the microcapsules used, the microcapsules expand to about five times the particle size before expansion. The particle size of microcapsules varies, and not all microcapsules have the same particle size.

A first ink receiving layer 14 is formed on the thermal expansion layer 13 . The first ink-receiving layer 14 is a layer that receives and fixes the ink used in the printing process, such as the ink of an inkjet printer. The ink-receiving layer 14 is formed using widely used materials according to the ink used in the printing process. For example, when water-based ink is used, the first ink-receiving layer 14 is formed using porous silica, for example, in a type that uses voids to receive ink. In the type that absorbs ink by swelling, the first ink-receiving layer 14 is formed using a resin selected from the group consisting of polyvinyl alcohol (PVA), polyester, polyurethane, acrylic, and the like. be. The first ink-receiving layer 14 is omitted if it is possible to fix the ink directly on the thermal expansion layer 13 according to the printing method, such as when using an ultraviolet curing type ink in an inkjet method. Is possible. Further, the first ink-receiving layer 14 can be omitted even if the surface of the thermally expandable sheet 10 does not need to be printed depending on the method of forming a stereoscopic image and/or the application of the thermally expandable sheet. be.

A second ink-receiving layer 15 is formed on the other surface of the substrate 11 (the lower surface shown in FIG. 1). The second ink-receiving layer 15 is a layer that receives and fixes ink used in the printing process, such as ink for an inkjet printer, like the first ink-receiving layer 14 . The second ink-receiving layer 15 is formed using the same material as the first ink-receiving layer 14 . In this embodiment, since a resin film is used as the substrate 11, this layer is necessary for fixing the ink constituting the photothermal conversion layer on the back surface of the substrate 11 (lower surface shown in FIG. 1). The second ink-receiving layer 15 may be omitted if no photothermal conversion layer is formed on the back surface.

(Method for producing thermally expandable sheet)
Next, a method for manufacturing the thermally expandable sheet 10 will be described with reference to FIGS. 2(a) to 2(d).
First, as the substrate 11, a sheet-like material made of resin, for example, a film made of polyethylene terephthalate (PET) is prepared. The base material 11 may be roll-shaped or pre-cut.

First, in order to form the second ink-receiving layer 15 on the back surface (lower surface shown in FIG. 2(a)) of the substrate 11, a material for the second ink-receiving layer 15, such as porous silica, PVA, etc., is used. A selected material is dispersed in a solvent to prepare a coating solution. Subsequently, this coating liquid is applied onto the rear surface of the base material 11 using a known coating device such as a bar coater, roller coater, or spray coater. Subsequently, the coating film is dried to form the second ink receiving layer 15 as shown in FIG. 2(a). By using a sheet in which the second ink-receiving layer 15 is formed in advance on the back surface of the base material 11, for example, a PET film in which an ink-receiving layer is formed on the outermost surface, such as an OHP (Overhead Projector) sheet, , the step of forming the second ink-receiving layer 15 can be omitted.

Next, in order to form the anchor layer 12 on one surface of the base material 11 (the upper surface shown in FIG. 2(a)), from the group consisting of polyester, acrylic, polyurethane, or any of these copolymers, A coating liquid (eg, aqueous dispersion) containing at least one selected resin is prepared. Subsequently, the coating liquid is applied onto the substrate 11 using a known coating device such as a bar coater, roller coater, or spray coater. Subsequently, the coating film is dried to form an anchor layer 12 as shown in FIG. 2(b).

In the step of forming the anchor layer 12, instead of the above, corona treatment may be performed using a corona treatment apparatus 60 schematically shown in FIG. The corona treatment apparatus 60 is, as shown in FIG. The base material 11 before treatment is guided to the treatment rolls 61 by the guide rolls 63 . When a high frequency high voltage is applied between the processing roll 61 and the electrode 62 from a high frequency power supply (not shown), corona discharge occurs between the processing roll 61 and the electrode 62 within the area indicated by the broken line in FIG. occurs. By passing the base material 11 under this corona discharge region, the surface of the base material 11 is subjected to corona treatment, and a surface modified layer (anchor layer 12 ) is formed on the base material 11 . Further, the corona treatment apparatus 60 is not limited to the roll-to-roll system, and may be of the single-wafer system.

Next, a binder made of a thermoplastic resin or the like and a thermally expandable material (thermally expandable microcapsules) are mixed to prepare a coating liquid for forming the thermally expandable layer 13 . Subsequently, the coating liquid is applied onto the anchor layer 12 using a known coating device such as a bar coater, roller coater, or spray coater. Subsequently, the coating film is dried to form the thermal expansion layer 13 as shown in FIG. 2(c). In order to obtain the target thickness of the thermal expansion layer 13, the coating and drying of the coating liquid may be performed multiple times.

Next, a coating liquid is prepared using a material that constitutes the first ink-receiving layer 14, such as a material selected from porous silica, PVA, and the like. Subsequently, this coating liquid is applied onto the thermal expansion layer 13 using a known coating device such as a bar coater, roller coater, or spray coater. In order to obtain the target thickness of the first ink-receiving layer 14, the application and drying of the coating liquid may be performed multiple times. Subsequently, the coating film is dried to form the first ink receiving layer 14 as shown in FIG. 2(d). Also, when the roll-shaped base material 11 is used, it is cut to a size suitable for the stereoscopic image forming system 70 .

The thermally expandable sheet 10 is manufactured through the above steps.
The step of forming the second ink-receiving layer 15 may be performed after the anchor layer 12, the thermal expansion layer 13 and the first ink-receiving layer 14 are formed.

(Stereoscopic image forming system)
Next, a three-dimensional image forming system 70 for forming a three-dimensional image on the thermally expandable sheet 10 of this embodiment will be described. As shown in FIGS. 4A to 4C, the stereoscopic image forming system 70 includes a control unit 71, a printing unit 72, an expansion unit 73, a display unit 74, a top board 75, and a frame 80. And prepare. 4A is a front view of the stereoscopic image forming system 70, FIG. 4B is a plan view of the stereoscopic image forming system 70 with the top plate 75 closed, and FIG. 3 is a plan view of the stereoscopic image forming system 70 with the top board 75 opened. FIG. 4A to 4C, the X direction is the same as the horizontal direction, the Y direction is the same as the conveying direction D in which the sheet is conveyed, and the Z direction is the same as the vertical direction. be. The X, Y and Z directions are orthogonal to each other.

The control unit 71, the printing unit 72, and the expansion unit 73 are placed in a frame 80 as shown in FIG. 4(a). Specifically, the frame 80 includes a pair of substantially rectangular side plates 81 and a connecting beam 82 provided between the side plates 81 , and a top plate 75 is provided above the side plates 81 . A printing unit 72 and an expansion unit 73 are arranged side by side in the X direction on a connecting beam 82 that spans between side plates 81 , and a control unit 71 is fixed below the connecting beam 82 . The display unit 74 is embedded in the top plate 75 so as to be flush with the top surface of the top plate 75 .

The control unit 71 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the printing unit 72 , expansion unit 73 and display unit 74 .

The printing unit 72 is an inkjet printing device. As shown in FIG. 4C, the printing unit 72 includes a loading section 72a for loading the thermally expandable sheet 10 and a discharge section 72b for discharging the thermally expandable sheet 10. As shown in FIG. The printing unit 72 prints the instructed image on the front or back surface of the thermally expandable sheet 10 carried in from the carry-in part 72a, and ejects the thermally expandable sheet 10 on which the image is printed from the delivery part 72b. The printing unit 72 also contains color inks (cyan (C), magenta (M), and yellow (Y)) for forming color ink layers 92, which will be described later, a front side light-to-heat conversion layer 91 and a back side light-to-heat conversion layer. A black ink (including carbon black) for forming 93 is provided. In order to form a black or gray color in the color ink layer 92, a black color ink that does not contain carbon black may be further provided as the color ink.

The printing unit 72 acquires color image data representing a color image (color ink layer 92) to be printed on the surface of the thermally expandable sheet 10 from the control unit 71, and prints color inks (cyan, magenta, yellow) is used to print a color image (color ink layer 92). The black or gray color of the color ink layer 92 is formed by mixing three colors of CMY or by further using black color ink that does not contain carbon black.

In addition, the printing unit 72 prints the front side photothermal conversion layer 91 using black ink based on surface foaming data, which is data indicating the portion to be foamed and expanded on the surface of the thermally expandable sheet 10 . Similarly, the backside photothermal conversion layer 93 is printed using black ink based on the backside foaming data indicating the portion to be foamed and expanded on the backside of the thermally expandable sheet 10 . Also, black ink containing carbon black is an example of a material that converts light into heat. The expansion height of the thermal expansion layer 13 increases as the density of the black ink increases. For this reason, the density of the black ink is determined so as to correspond to the target height.

The expansion unit 73 is an expansion device that applies heat to the thermally expandable sheet 10 to expand it. As shown in FIG. 4(c), the expansion unit 73 includes a loading section 73a for loading the thermally expandable sheet 10 and a discharge section 73b for discharging the thermally expandable sheet 10. As shown in FIG. The expansion unit 73 applies heat to the thermally expandable sheet 10 carried in from the carry-in portion 73a to expand it, and discharges the expanded thermally expandable sheet 10 from the discharge portion 73b. The expansion unit 73 has an irradiation section (not shown) inside. The irradiation unit is, for example, a halogen lamp, and irradiates the thermally expandable sheet 10 with near infrared region (wavelength 750 to 1400 nm), visible light region (wavelength 380 to 750 nm) or mid infrared region (wavelength 1400 to 4000 nm). ). When the thermally expandable sheet 10 printed with black ink containing carbon black is irradiated with light, the area printed with the black ink converts the light into heat more efficiently than the area not printed with the black ink. be done. Therefore, the area of the thermal expansion layer 13 printed with black ink is mainly heated. As a result, the thermally expandable material in the area printed with black ink is foamed, and the thermally expandable layer 13 expands.

The display unit 74 is composed of a touch panel or the like. The display unit 74 displays an image (a star shown in FIG. 4B) printed on the thermally expandable sheet 10 by the printing unit 72, as shown in FIG. 4B, for example. The display unit 74 also displays operation guides and the like, and the user can operate the stereoscopic image forming system 70 by touching the display unit 74 .

(Stereoscopic image forming process)
Next, with reference to the flow chart shown in FIG. 5 and the cross-sectional views of the thermally expandable sheet 10 shown in FIGS. The flow of forming processing will be described.

First, the user prepares the thermally expandable sheet 10 before the stereoscopic image is formed, and designates color image data, surface foaming data and back foaming data via the display unit 74 . Then, the thermally expandable sheet 10 is inserted into the printing unit 72 with its surface facing upward. The printing unit 72 prints a photothermal conversion layer (front side photothermal conversion layer 91) on the surface of the inserted thermally expandable sheet 10 (step S1). The front photothermal conversion layer 91 is a layer formed of a material that converts light into heat, specifically black ink containing carbon black. The printing unit 72 ejects black ink containing carbon black onto the surface of the thermally expandable sheet 10 according to the specified surface foaming data. As a result, a front side photothermal conversion layer 91 is formed on the first ink receiving layer 14, as shown in FIG. 6(a). In order to facilitate understanding, the illustration shows that the front side photothermal conversion layer 91 is formed on the first ink receiving layer 14. More precisely, the black ink is formed on the first ink receiving layer 14. A light-to-heat conversion layer is formed in the first ink-receiving layer 14 because it is received therein.

Second, the user inserts the thermally expandable sheet 10 printed with the photothermal conversion layer 91 into the expansion unit 73 with its surface facing upward. The expansion unit 73 heats the inserted thermally expandable sheet 10 by irradiating light from the surface thereof (step S2). Specifically, the expansion unit 73 irradiates the surface of the thermally expandable sheet 10 with light through the irradiation section. The front photothermal conversion layer 91 printed on the surface of the thermally expandable sheet 10 generates heat by absorbing the irradiated light. As a result, as shown in FIG. 6B, the area of the thermally expandable sheet 10 where the front photothermal conversion layer 91 is printed rises and expands. In addition, in FIG. 6B, if the density of the black ink of the front side light-to-heat conversion layer 91 shown on the right side is made darker than that of the front side light-to-heat conversion layer 91 shown on the left side, as shown in the figure, the darkly printed area becomes It is possible to inflate higher.

Third, the user inserts the thermally expandable sheet 10 whose surface has been heated and expanded into the printing unit 72 with the surface facing upward. The printing unit 72 prints a color image (color ink layer 92) on the surface of the inserted thermally expandable sheet 10 (step S3). Specifically, the printing unit 72 ejects cyan C, magenta M, and yellow Y inks onto the surface of the thermally expandable sheet 10 in accordance with designated color image data. As a result, a color ink layer 92 is formed on the first ink receiving layer 14 and the front photothermal conversion layer 91, as shown in FIG. 6(c).

Fourth, the user inserts the thermally expandable sheet 10 printed with the color ink layer 92 into the expansion unit 73 with the back surface facing upward. The expansion unit 73 heats the inserted thermally expandable sheet 10 from the rear surface to dry the color ink layer 92 formed on the surface of the thermally expandable sheet 10 (step S4). Specifically, the expansion unit 73 irradiates the back surface of the thermally expandable sheet 10 with light through the irradiation unit, heats the color ink layer 92 , and volatilizes the solvent contained in the color ink layer 92 .

Fifth, the user inserts the thermally expandable sheet 10 on which the color ink layer 92 is printed into the printing unit 72 with the back surface facing upward. The printing unit 72 prints a photothermal conversion layer (back photothermal conversion layer 93) on the back surface of the inserted thermally expandable sheet 10 (step S5). Like the photothermal conversion layer 91 printed on the front side of the thermally expandable sheet 10, the backside photothermal conversion layer 93 is a layer formed of a material that converts light into heat, specifically, a black ink containing carbon black. be. The printing unit 72 ejects black ink containing carbon black onto the back surface of the thermally expandable sheet 10 according to the designated back surface foaming data. As a result, a back photothermal conversion layer 93 is formed on the back surface of the substrate 11, as shown in FIG. 6(d). As for the back side photothermal conversion layer 93, if the density of the black ink of the back side photothermal conversion layer 93 shown on the right side is made darker than that of the back side photothermal conversion layer 93 shown on the left side, the darkly printed area becomes higher as shown in the figure. It can be inflated.

Sixth, the user inserts the thermally expandable sheet 10 with the backside photothermal conversion layer 93 printed into the expansion unit 73 with the backside facing upward. The expansion unit 73 irradiates the inserted thermally expandable sheet 10 with light from the rear surface to heat it (step S6). More specifically, the expansion unit 73 irradiates the rear surface of the thermally expandable sheet 10 with light through an irradiation section (not shown). The backside photothermal conversion layer 93 printed on the backside of the thermally expandable sheet 10 generates heat by absorbing the irradiated light. As a result, as shown in FIG. 6(e), the area of the thermally expandable sheet 10 where the backside photothermal conversion layer 93 is printed rises and expands.

A three-dimensional image is formed on the thermally expandable sheet 10 by the procedure described above.

The photothermal conversion layer may be formed only on the front side or only on the back side. When the photothermal conversion layer is printed only on the front side, steps S1 to S4 of the above processes are performed. On the other hand, when the photothermal conversion layer is formed only on the back side, steps S3 to S6 are performed among the above processes.

According to the thermally expandable sheet 10 and the method for manufacturing the thermally expandable sheet 10 of the present embodiment, by providing the anchor layer 12 between the substrate 11 and the thermally expandable layer 13, the resin sheet is used as the substrate 11. is used, it is possible to suppress separation of the thermal expansion layer 13 from the substrate 11 when the thermal expansion layer 13 is expanded.

Further, in the method of manufacturing the thermally expandable sheet 10, the substrate 11 having an ink receiving layer formed in advance on one of its surfaces is used, and the previously formed ink receiving layer is used as the second ink receiving layer 15. By using as, it is possible to simplify the manufacturing process.

(Example)
Next, as an example, a thermally expandable sheet in which an anchor layer is formed on a base material in the same manner as in the present embodiment and a thermally expandable layer is further formed on the anchor layer, and as a comparative example, a thermally expandable sheet without an anchor layer is provided. An example in which a thermally expandable sheet having a thermally expandable layer formed on a substrate is heated and expanded will be described. A polyethylene terephthalate (PET) having a thickness of 100 μm was used as a substrate in both Examples and Comparative Examples. As the anchor layer, "WAC-17XC" manufactured by Takamatsu Yushi Co., Ltd. was used, and the anchor layer was formed to have a thickness of several μm. The thermal expansion layer was formed under the same conditions in both Examples and Comparative Examples.

Photothermal conversion layers with different black densities were formed on the surfaces of these thermally expandable sheets. The black density is the density of black (K) on the color data when printing the photothermal conversion layer. K100 is so-called solid black (K100%). K10, K20, K30, K40, K50, K60, K70, K80 and K90 are black (K) densities on the color data of 10%, 20%, 30%, 40%, 50% and 60%, respectively. , 70%, 80% and 90%. The photothermal conversion layer was formed only on the front side of the thermally expandable sheet, and all the photothermal conversion layers were formed in the same shape.

Two levels were set for the amount of heating (amount of light irradiation). The first is the level at which the amount of heat is large and peeling occurs in the region with high black density in both the example and the comparative example (Fig. 7(a)). This is the level that occurs (FIG. 7(b)). The thermally expandable sheets of Examples and Comparative Examples were irradiated with light at these two levels to foam and expand the thermally expandable layers, and the expansion height (convexity) of the thermally expandable layers was measured. Since the photothermal conversion layers with different densities provided on the thermally expandable sheet are irradiated with light under the same conditions, the photothermal conversion layers with higher black densities generate more heat. Therefore, the area of the thermal expansion layer where the photothermal conversion layer with a higher black density is formed is heated more.

FIG. 7(a) shows the amount of protrusion (mm) of the thermally expandable sheets of Examples and Comparative Examples at the first level (large amount of heating). In Examples, peeling of the thermal expansion layer occurred at K100. However, as shown in FIG. 7(a), the thermal expansion layer did not separate up to K90, and a convex amount corresponding to the heating amount was obtained. On the other hand, in the comparative example, peeling did not occur up to K60, but peeling occurred after K70.

Next, FIG. 7B shows the amount of protrusion (mm) of the thermally expandable sheets of the example and the comparative example at the second level (low heating amount). In the example, as shown in FIG. 7A, the thermal expansion layer did not peel off up to K100, and the amount of protrusion corresponding to the amount of heating was obtained. On the other hand, in the comparative example, peeling did not occur up to K60, but peeling occurred after K70.

As described above, from FIGS. 7A and 7B, it has been clarified that in Examples, the provision of the anchor layer increases the adhesiveness between the base material and the thermal expansion layer, thereby suppressing the peeling. . Further, in both the examples and the comparative examples, the amount of protrusion increased along substantially the same curve until peeling occurred, and it was clear that the anchor layer did not particularly affect the expansion of the thermal expansion layer.

(Embodiment 2)
A thermally expandable sheet 20 according to Embodiment 2 is shown in FIG. The thermally expandable sheet 20 of Embodiment 2 differs from the thermally expandable sheet 10 of Embodiment 1 in that the ink receiving layer is used as an anchor layer 22 . Components similar to those of the first embodiment are given the same numbers, and detailed descriptions thereof are omitted.

The thermally expandable sheet 20 comprises a substrate 11, an anchor layer 22, a thermally expandable layer 13 and a first ink receiving layer 14, as shown in FIG. The substrate 11, the thermally expandable layer 13, and the first ink receiving layer 14 are the same as those of the thermally expandable sheet 10 according to the first embodiment.

Further, in the present embodiment, since the configuration including only the first ink receiving layer 14 is taken as an example, the photothermal conversion layer is formed only on the front side. Therefore, the stereoscopic image forming process performs steps S1 to S4 of the flow chart shown in FIG. The thermally expandable sheet 20 may have the second ink receiving layer 15 on the back surface of the base material 11 as in the first embodiment. In this case, the stereoscopic image forming process (steps S1 to S6 in the flow chart shown in FIG. 5) similar to that of the first embodiment is performed.

The anchor layer 22 of the present embodiment is formed of a material capable of receiving and fixing ink from an inkjet printer, similar to the material used for the first ink-receiving layer 14 . Furthermore, the anchor layer 22 has good adhesion to the material forming the thermal expansion layer 13 . As the anchor layer 22, for example, one or a plurality of resins selected from the group consisting of polyvinyl alcohol (PVA), polyester, polyurethane, acrylic, etc., which is used as a type that swells and accepts ink, is used. can be used. These materials can swell and accept ink, but also have good adhesion to the material forming the thermal expansion layer 13 . Therefore, it is possible to function as the anchor layer 22 as well. As the anchor layer 22, any material other than the materials described above can be used as long as the material is used for receiving ink and has good adhesion to the thermal expansion layer 13.

(Method for producing thermally expandable sheet)
Next, a method for manufacturing the thermally expandable sheet 20 will be described with reference to FIGS. 9(a) to 9(c).
First, a sheet-shaped material such as a PET film is prepared as the base material 11 . The base material 11 may be roll-shaped or pre-cut.

First, on the surface of the substrate 11 (upper surface shown in FIG. 9A), one or a plurality of materials selected from materials constituting the anchor layer 22, such as PVA, polyester resin, polyurethane resin, acrylic resin, etc., are applied. A coating liquid is prepared using the materials. Subsequently, this coating liquid is applied onto the substrate 11 using a known coating device such as a bar coater, roller coater, or spray coater. Subsequently, the coating film is dried to form an anchor layer 22 as shown in FIG. 9(a). If a sheet (for example, an OHP film) in which an ink-receiving layer made of the material described above is pre-formed on the surface of the substrate 11 is used, the pre-formed ink-receiving layer can be used as the anchor layer 22. can. This makes it possible to omit the step of forming the anchor layer 22, which is preferable.

Next, as in the first embodiment, a thermally expandable layer 13 is formed on the anchor layer 22 using a binder made of thermoplastic resin or the like and a thermally expandable material (thermally expandable microcapsules). Subsequently, a first ink receiving layer 14 is formed on the thermal expansion layer 13 . When the roll-shaped base material 11 is used, it is cut to a size suitable for the stereoscopic image forming system 70 .

The thermally expandable sheet 20 is manufactured through the above steps.
In addition to the above steps, a step of forming the second ink-receiving layer 15 on the back surface of the substrate 11 may be further performed in the same manner as in the first embodiment.

According to the thermally expandable sheet 20 and the method for manufacturing the thermally expandable sheet 20 of the present embodiment, the layer used as the ink-receiving layer functions as the anchor layer 22, so that when the thermally expandable layer 13 is expanded, the thermally expandable layer 13 is thermally expanded. Detachment of the layer 13 from the substrate 11 can be suppressed. In particular, if a sheet having an ink-receiving layer formed in advance on one side of the substrate 11 is used, the step of forming the anchor layer 22 can be omitted, and the manufacturing process can be simplified. preferred.

In addition, for example, Embodiment 1 and Embodiment 2 have different layer configurations, but a substrate having an ink-receiving layer formed on the outermost surface (uppermost surface) of one of the surfaces is obtained, and this substrate is used. If another layer is formed on the base, it becomes possible to share members between different embodiments. For example, a substrate having an ink-receiving layer on the outermost surface of one surface is prepared. By using this ink-receiving layer as the second ink-receiving layer 15 in Embodiment 1 and forming the anchor layer 12, the thermal expansion layer 13, etc. on the other surface, the thermally expandable sheet 10 of Embodiment 1 is manufactured. be able to. On the other hand, when the pre-formed ink-receiving layer has good adhesiveness with the thermal expansion layer, this layer can be used as the anchor layer 22, and the thermal expansion layer 13 and the like can be formed on the anchor layer 22. , the thermally expandable sheet 20 according to Embodiment 2 can be manufactured. Therefore, according to the production method of the present embodiment, it is possible to obtain the effect that the members can be shared in the production method of the thermally expandable sheet having different layer structures, which is preferable.

(Embodiment 3)
A thermally expandable sheet 30 according to Embodiment 3 is shown in FIG. The thermally expandable sheet 30 according to Embodiment 3 differs from the thermally expandable sheet 10 according to Embodiment 1 in that an anchor layer 32 is formed on the third ink receiving layer 31 . Components similar to those of the first embodiment are given the same numbers, and detailed descriptions thereof are omitted.

The thermally expandable sheet 30 comprises a substrate 11, a third ink-receiving layer 31, an anchor layer 32, a thermally-expandable layer 13 and a first ink-receiving layer 14, as shown in FIG. The thermally expandable sheet 20 may have the second ink receiving layer 15 on the back surface of the base material 11 as in the first embodiment.

The third ink-receiving layer 31 is made of a material capable of receiving and fixing ink of an inkjet printer, like the material constituting the first ink-receiving layer 14 . Unlike the anchor layer 22 of the second embodiment, the third ink-receiving layer 31 is a layer capable of receiving the ink of an inkjet printer, but its adhesiveness to the thermal expansion layer 13 is lower than that of the anchor layer 22. lower layer. For example, the third ink-receiving layer 31 is made of porous silica or the like, which is of a type that utilizes voids.

The anchor layer 32 is a layer made of the same material as the anchor layer 12 of Embodiment 1 and having good adhesion to the third ink receiving layer 31 and the thermal expansion layer 13 . By providing the anchor layer 32 on the third ink-receiving layer 31, the third ink-receiving layer 31 and the thermal expansion layer 13 are well adhered, and when the thermal expansion layer 13 is expanded, the thermal expansion layer 13 detachment from the substrate 11 can be suppressed.

(Method for producing thermally expandable sheet)
Next, a method for manufacturing the thermally expandable sheet 30 will be described with reference to FIGS. 11(a) to 11(d).
First, a resin sheet such as a PET film is prepared as the substrate 11 . The base material 11 may be roll-shaped or pre-cut.

A coating liquid is prepared using a material, such as porous silica, for forming the third ink-receiving layer 31 on the surface of the substrate 11 (shown in FIG. 11(a)). Subsequently, this coating liquid is applied onto the substrate 11 using a known coating device such as a bar coater, roller coater, or spray coater. Subsequently, the coating film is dried to form a third ink receiving layer 31 as shown in FIG. 11(a). If a sheet (for example, an OHP film) having an ink-receiving layer made of the material described above is used, the step of forming the third ink-receiving layer 31 on the substrate 11 can be omitted. possible and preferable.

Next, in order to form the anchor layer 32 on the third ink-receiving layer 31, a coating liquid containing a material to be used as the anchor layer 32 is prepared. The anchor layer 32 is selected from materials used as the anchor layer 12 shown in the first embodiment. Subsequently, the coating liquid is applied onto the substrate 11 using a known coating device such as a bar coater, roller coater, or spray coater. Next, the coating film is dried to form an anchor layer 32 as shown in FIG. 11(b).

Next, as in the first embodiment, a binder made of a thermoplastic resin or the like and a thermally expandable material (thermally expandable microcapsules) are used to anchor the thermally expandable layer 13 as shown in FIG. It is formed over layer 32 . Subsequently, as shown in FIG. 11(d), the first ink receiving layer 14 is formed on the thermal expansion layer 13. Then, as shown in FIG. When the roll-shaped base material 11 is used, it is cut to a size suitable for the stereoscopic image forming system 70 .

The heat expandable sheet 30 is manufactured through the above steps.
In addition to the above steps, a step of forming the second ink-receiving layer 15 on the back surface of the substrate 11 may be further carried out.

According to the thermally expandable sheet 30 and the method for manufacturing the thermally expandable sheet 30 of the present embodiment, by providing the anchor layer 32 on the third ink-receiving layer 31, the third ink-receiving layer 31 and the thermal expansion It adheres well to the layer 13 , and can suppress separation of the thermal expansion layer 13 when the thermal expansion layer 13 is expanded. For example, a sheet having a plastic film such as PET used in Embodiment 1 as the base material 11 and an ink receiving layer formed in advance on one side of the base material 11 is obtained. If it is used as the third ink-receiving layer 31 and the anchor layer 32 is formed on the third ink-receiving layer 31, the manufacturing process can be simplified.

In addition, for example, Embodiment 1 and Embodiment 3 have different layer configurations, but a base material having an ink-receiving layer formed on one side is obtained, and another layer is formed on this base material. By forming , it is possible to share members between different embodiments. For example, a substrate provided with an ink-receiving layer on one side is prepared. By using this ink-receiving layer as the second ink-receiving layer 15 in Embodiment 1 and forming an anchor layer, a thermal expansion layer, etc. on the other surface, the thermally expandable sheet 10 of Embodiment 1 can be produced. can. On the other hand, when a previously provided ink-receiving layer is used as the third ink-receiving layer 31 and this layer has low adhesiveness to the thermal expansion layer, an anchor layer is formed on the third ink-receiving layer 31 . 32 is formed, and a thermally expandable layer or the like is provided on the anchor layer 32, the thermally expandable sheet 30 according to the third embodiment can be manufactured. Therefore, according to the manufacturing method of the present embodiment, parts can be shared in the manufacturing method of thermally expandable sheets having different layer configurations, which is preferable.

The present invention is not limited to the above-described embodiments, and various applications are possible.
In each of the above-described embodiments, a configuration in which the second ink-receiving layer 15 is provided on the back surface of the substrate 11, or a configuration in which the second ink-receiving layer 15 is not provided is exemplified. An adhesive layer and a release paper may be provided on the back surface of the material 11 . By providing the adhesive layer and the release paper, it becomes possible to attach the thermally expandable sheet on which the stereoscopic image is printed to various objects such as containers.

For example, a thermally expandable sheet 40 shown in FIG. 12 is obtained by providing an adhesive layer 45 and a release paper 46 on the back surface of the thermally expandable sheet 20 shown in the second embodiment. In this case, as shown in FIG. 12, the thermally expandable sheet 40 includes a base material 11, an anchor layer 22, a thermally expandable layer 13, a first ink receiving layer 14, an adhesive layer 45, and a release paper 46. The adhesive layer 45 is a commonly used adhesive, and is appropriately selected according to the object to which the thermally expandable sheet 40 is attached. The release paper 46 is made of a material commonly used as a backing paper for stickers and the like. Moreover, the release paper 46 is not limited to paper, and may be a film. The anchor layer 22 is formed of a material that is also used as an ink-receiving layer, as in the second embodiment, and is a layer having good adhesion to the thermal expansion layer 13 . Also, the second ink receiving layer 15 may be provided on the release paper 46 (the lower surface of the release paper 46 in FIG. 12).

Further, when manufacturing the thermally expandable sheet 40, the ink receiving layer (anchor layer 22) is provided on one side of the substrate 11, and the adhesive layer 45 and release paper 46 are provided on the other side. It is preferable to obtain a sheet and use this sheet to form the thermal expansion layer 13, etc., because the manufacturing process can be simplified.

Similarly, a thermally expandable sheet 50 shown in FIG. 13 is obtained by providing an adhesive layer 45 and release paper 46 on the back surface of the thermally expandable sheet 30 shown in the third embodiment. In this case, as shown in FIG. 13, the thermally expandable sheet 50 includes the substrate 11, the third ink-receiving layer 31, the anchor layer 32, the thermally-expandable layer 13, the first ink-receiving layer 14, the adhesive layer 45 and A release paper 46 is provided. The adhesive layer 45 is a commonly used adhesive, and is appropriately selected according to the object to which the thermally expandable sheet 50 is attached. The release paper 46 is made of a material commonly used as a backing paper for stickers and the like. The third ink-receiving layer 31 is a layer that receives and fixes ink as in the third embodiment, but has low adhesiveness to the thermal expansion layer 13 . The anchor layer 32 is a layer having good adhesion to the thermal expansion layer 13 as in the third embodiment, and is a layer having good adhesion to the thermal expansion layer 13 . Also, the second ink receiving layer 15 may be provided on the release paper 46 (the lower surface of the release paper 46 in FIG. 13).

Further, when manufacturing the thermally expandable sheet 50, the ink receiving layer (the third ink receiving layer 31) is provided on one side of the substrate 11, and the adhesive layer 45 and release paper 46 are provided on the other side. It is preferable to obtain a sheet provided with and use this sheet to form the anchor layer 32, the thermal expansion layer 13, etc., because the manufacturing process can be simplified.

The drawings used in each embodiment are for explaining each embodiment. Therefore, it is not intended that the thickness of each layer of the thermally expandable sheet be interpreted as being formed at the ratios shown in the drawings. For example, although the substrate 11 is illustrated thinner than the thermal expansion layer 13 in FIG. not excluded. The same applies to other layers.

Although several embodiments of the present invention have been described, the present invention is included in the scope of the invention described in the claims and equivalents thereof. The invention described in the original claims of the present application is appended below.

[Appendix 1]
an anchor layer formed on one surface of the substrate;
a thermal expansion layer formed on the anchor layer;
The base material is a film made of resin,
The anchor layer contains at least one resin selected from the group consisting of polyester, acrylic, polyurethane, or copolymers thereof,
A thermally expandable sheet characterized by:
[Appendix 2]
The anchor layer contains a polyester-acrylic-urethane composite resin,
The thermally expandable sheet according to Supplementary Note 1, characterized by:
[Appendix 3]
An ink-receiving layer is formed on one surface of the substrate,
the anchor layer is formed on the ink-receiving layer;
The thermally expandable sheet according to appendix 1 or 2, characterized by:
[Appendix 4]
forming an anchor layer on one side of the substrate;
forming a thermal expansion layer on the anchor layer;
The base material is a film made of resin,
In the step of forming the anchor layer,
On one side of the substrate, using at least one resin selected from the group consisting of polyesters, acrylics, polyurethanes, or copolymers thereof, or on one side of the substrate forming an anchor layer by subjecting it to corona treatment,
A method for producing a thermally expandable sheet, characterized by:
[Appendix 5]
The resin used in the step of forming the anchor layer is a polyester-acrylic-urethane composite resin,
A method for producing a thermally expandable sheet according to appendix 4, characterized in that:
[Appendix 6]
An ink-receiving layer is provided on one surface of the substrate,
forming the anchor layer by applying the resin onto the ink-receiving layer;
The thermally expandable sheet according to appendix 4 or 5, characterized by:

10, 20, 30, 40, 50 Thermally expandable sheet 11 Base material 12, 22, 32 Anchor layer 13 Thermally expandable layer 14 First layer Ink-receiving layer 15 Second ink-receiving layer 31 Third ink-receiving layer 45 Adhesive layer 46 Release paper 60 Corona treatment device 61. Processing roll 62 Electrode 63 Guide roller 70 3D image forming system 71 Control unit 72 Printing unit 72a Loading section 72b . Side plate 82 Connection beam 91 Front photothermal conversion layer 92 Color ink layer 93 Back photothermal conversion layer

Claims (3)

A step of forming an anchor layer by applying a predetermined ink onto one surface of a substrate, which is a film made of resin;
forming a thermal expansion layer on the anchor layer;
forming a first ink-receiving layer by applying an ink having the same component composition as the ink on the outermost surface of the substrate on the side where the thermal expansion layer is provided;
including
The ink contains one or more resins selected from the group consisting of polyvinyl alcohol (PVA), polyurethane, and acrylic.
A method for producing a thermally expandable sheet, characterized by: In the step of forming the anchor layer, the anchor layer is formed on the substrate on which the ink receiving layer containing porous silica is formed .
The method for producing a thermally expandable sheet according to claim 1 , characterized in that: The step of forming the anchor layer includes preparing the substrate having an adhesive layer and a release paper formed on the other surface, and forming the anchor layer on the one surface of the substrate;
A second ink-receiving layer is formed on the surface of the release paper opposite to the surface facing the adhesive layer.
The method for producing a thermally expandable sheet according to claim 1 , characterized in that:

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