Coating container and coating container set for producing paper-containing three-dimensional structure, and method for producing paper-containing three-dimensional structure using the same

Abstract

To provide a coating type container and a coating type container set for producing a paper-containing three-dimensional structure that can easily bend paper by applying ink and provides stable writing comfort, and a method for producing a paper-containing three-dimensional structure using the same.SOLUTION: The coating type container of the present invention is a coating type container that applies ink to one surface of a paper-containing sheet made of paper or having paper as a main component, and the ink is dried on the applied portion, so that a paper-containing three-dimensional structure is produced by autonomously folding the paper-containing sheet with the one surface facing inward at the applied portion. The ink contains water and a thickener.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a coating type container and a coating type container set for producing a paper-containing three-dimensional structure, and a method for producing a paper-containing three-dimensional structure using the same. [Background technology]

[0002] Origami technology has the advantage of being able to create a variety of three-dimensional structures by folding a single sheet of paper, and by devising folding patterns, it is possible to repeatedly use the functions of unfolding and storing, and it is possible to create structures with relatively high mechanical strength, so it is expected to be applied in a variety of fields. For example, origami technology can be expected to be applied to the manufacture of three-dimensional electronic devices, the manufacture of lightweight and inexpensive shock-absorbing materials, and space-saving by folding sheets.

[0003] In this context, autonomous paper folding technology, in which paper is made to bend by applying some kind of external force to the paper, has attracted attention, and this type of technology is sometimes referred to as "self-folding." It is expected that the development of such autonomous paper folding technology will greatly advance the utilization of the above-mentioned properties of origami.

[0004] Previously, a folding technique that uses a material that responds to an external stimulus placed on the paper to autonomously fold the paper by utilizing the response of the material when the stimulus is applied has been reported. The stimulus can be an electric current, heat, or the like.

[0005] However, such folding techniques require the supply of some kind of energy, such as electric current or heat, which may limit the environments in which they can be used. In addition, the paper must be modified with special materials, which increases costs.

[0006] As a method capable of solving such problems, a method has been disclosed in which an aqueous solution containing 2-propanol is ejected onto paper using an inkjet printer and then dried (see Non-Patent Document 1). This method has the advantage of being highly practical, since it does not require the supply of energy such as electric current or heat to the paper, and there is no need to modify the paper with a special material. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Hiroki Shigemune, Shingo Maeda, Yusuke Hara, and Shuji Hashimoto. “Design of paper mechatronics:Towards a fully printed robot” Proceedings of 2014 IEEE / RSJ International Conference on Intelligent Robots and Systems(IROS 2014) Summary of the Invention [Problem to be solved by the invention]

[0008] The method disclosed in Non-Patent Document 1 is useful in that it can solve the problems of other methods, but further improvements are required for application to practical three-dimensional structures. Furthermore, the usefulness of such folding technology will be further enhanced if it can be applied not only to paper but also to composite paper that combines paper with other materials.

[0009] When considering commercialization of a product that allows easy bending and easy use of paper, applying the ink with a pen is easier and more enjoyable than inkjet printing. However, the ink in the technology of Non-Patent Document 1 is a solution with a low viscosity suitable for inkjet printing, so when applied to a pen container, the ink leaks from the pen tip and cannot be applied stably. When ingredients other than water are added to the ink, this may affect the autonomous formation of the paper, so a technology that allows stable application with a pen without interfering with the autonomous formation of the paper was desired.

[0010] The present invention has been made in consideration of the above circumstances, and has an objective of providing an application-type container and application-type container set for producing a paper-containing three-dimensional structure, which allows paper to be easily bent by applying ink and provides a stable writing feel, and a method for producing a paper-containing three-dimensional structure using the same. [Means for solving the problem]

[0011] In order to solve the above problems, the coated container of the present invention is a coated container for producing a paper-containing three-dimensional structure by applying ink to one side of a paper-containing sheet made of paper or containing paper as a main component, and drying the ink at the applied area, thereby autonomously folding the paper-containing sheet at the applied area with the one side facing inward, and is characterized in that the ink contains water and a thickener.

[0012] In a preferred embodiment of this coated container, ink is applied to the one surface, thereby causing water to penetrate into the paper-containing sheet from that one surface, creating one or more regions on the paper-containing sheet that have a water concentration gradient in the thickness direction of the paper-containing sheet, and the paper-containing sheet in a state having the water concentration gradient is dried, thereby causing the paper-containing sheet to autonomously fold at the region that had the water concentration gradient, thereby creating a paper-containing three-dimensional structure.

[0013] The coated container set for producing a paper-containing three-dimensional structure of the present invention is characterized by having the coated container and a paper-containing sheet made of paper or containing paper as a main component, one side of which can be coated with ink from the coated container and the ink can be dried at the coated area to autonomously fold the one side inward to produce a paper-containing three-dimensional structure.

[0014] The method for producing a paper-containing three-dimensional structure of the present invention is a method for producing a paper-containing three-dimensional structure formed by folding a paper-containing sheet made of paper or containing paper as a main component,

[0015] a step (A) of applying ink containing water and a thickener to one side of the paper-containing sheet using a coating container having the ink therein, thereby causing water to penetrate into the paper-containing sheet from one side thereof, thereby creating one or more portions on the paper-containing sheet having a water concentration gradient in the thickness direction of the paper-containing sheet; The method is characterized by including a step (B) of drying the paper-containing sheet having the water concentration gradient, thereby causing the paper-containing sheet to autonomously fold at the portion that had the water concentration gradient, thereby producing a paper-containing three-dimensional structure. Effect of the Invention

[0016] According to the present invention, by utilizing origami techniques, paper can be easily bent by applying ink, providing a stable writing experience. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view for illustrating a schematic example of step (A) of the method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view for illustrating a schematic example of step (A) of the method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention. [Diagram 3]FIG. 2 is a cross-sectional view for illustrating a schematic example of step (A) of the method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view for illustrating a schematic example of step (B) in the method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram showing an example of a type of applicator container that can be used in the present invention. [Figure 6] FIG. 1 is a perspective view showing an example of a paper-containing sheet used in the present embodiment and a target paper-containing three-dimensional structure. [Figure 7] FIG. 2 is a cross-sectional view showing another example of a paper-containing sheet having a water concentration gradient and a target paper-containing three-dimensional structure in the present embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing another example of a paper-containing sheet in which a portion having a water concentration gradient is produced, and a target paper-containing three-dimensional structure in this embodiment. [Figure 9] FIG. 1 is a perspective view showing an example of a paper-containing sheet used in the present embodiment and a target paper-containing three-dimensional structure. [Figure 10] Photographs showing the bent state of paper after ink was applied in the width direction and flow direction (left) and the pen tip when ink was supplied (right) showing the results of Comparative Examples 1 to 6. (a) shows the results of Comparative Examples 1 to 3, in which water was used as the ink, and (b) shows the results of Comparative Examples 4 to 6, in which a mixture of water and alcohol was used as the ink. [Figure 11] These are photographs (top) showing the state of bending of paper after ink is applied in the width direction and flow direction, and (bottom) a photograph of the pen tip when ink is supplied, showing the results of Examples 1 to 6 and Comparative Examples 7 and 8. (a) shows the results of Comparative Example 7 and Examples 1 to 3, where water and a thickener were used in the ink, and (b) shows the results of Comparative Example 8 and Examples 4 to 6, where a mixture of water and alcohol and a thickener was used in the ink. [Figure 12]Photographs showing the bending state of paper after ink is applied in the width direction and flow direction (top) and the pen tip when ink is supplied (bottom) for the results of Examples 7 to 10 and Comparative Examples 9 to 12. (a) shows the results of Comparative Examples 9 and 10 and Examples 7 and 8 in which the pen tip thickness was changed for a valve-type pen, and (b) shows the results of Comparative Examples 11 and 12 and Examples 9 and 10 in which the type of pen container was changed. [Figure 13] Photographs showing the bending state of paper after ink is applied in the width direction and flow direction (top) and the pen tip when ink is supplied (bottom) show the results of Examples 11 to 13. (a) shows the results of Example 11, in which the type of thickener was changed, and (b) shows the results of Example 12, in which no dye was added to the ink, and Example 13, in which a dye was added. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention will be described in detail below with reference to the drawings. Note that the drawings used in the following description may show essential parts in an enlarged scale for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0019] 1 to 4 are diagrams for illustrating an example of a method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention, where FIG. 1 is an oblique view and FIGS. 2 to 4 are cross-sectional views.

[0020] The application type container 1 of the present embodiment shown in Fig. 1 is a application type container for applying ink 2 to one side 3a of a paper-containing sheet 3 made of paper or containing paper as a main component, and drying the ink 2 at the applied portion to autonomously fold the paper with the one side 3a facing inward at the applied portion, thereby producing a paper-containing three-dimensional structure 5 as shown in Fig. 4. The ink 2 contains water and a thickener. Figs. 1 to 4 show a case where a pen is used as an example of the application type container 1. More specifically, the production of the paper-containing three-dimensional structure 5 includes the following steps (A) and (B).

[0021] In step (A), ink 2 containing water and a thickener is applied to one side 3a of a paper-containing sheet 3 using an applicator container 1 having ink 2, thereby causing water 2a to penetrate into the paper-containing sheet 3 from one side 3a, and creating one or more regions 4 in the paper-containing sheet 3 having a concentration gradient of water 2a in the thickness direction of the paper-containing sheet 3.

[0022] In step (B), the paper-containing sheet 3 having a water concentration gradient is dried, whereby the paper-containing sheet 3 is autonomously folded at the portion 4' that had the water concentration gradient to produce a paper-containing three-dimensional structure 5. <Process (A)> 1 to 3 are diagrams for illustrating an example of step (A) in the method for producing a paper-containing three-dimensional structure using a coating-type container according to one embodiment of the present invention.

[0023] In step (A), as shown in Fig. 1, ink 2 containing water and a thickener is applied to one side 3a of a paper-containing sheet 3 using an applicator container 1 having ink 2 containing water and a thickener. In the example of Fig. 1, a pen, which is a writing applicator, is used, and ink 2 is filled in a pen container 1a and applied from a pen tip 1b to one side 3a of the paper-containing sheet 3. In Fig. 1, ink 2 is applied linearly in a direction parallel to the one side 3a of the paper-containing sheet 3 (in other words, in the surface direction). That is, the ink 2 shown here is applied in a continuous line in a direction parallel to one side 1a of the paper-containing sheet 1.

[0024] As a result, as shown in FIG. 2(a), the ink 2 (and the water 2a contained therein) is adhered to one side 3a of the paper-containing sheet 3, and as shown in FIG. 2(b), the water 2a is allowed to penetrate into the paper-containing sheet 3 from one side 3a.

[0025] At this time, by applying an appropriate amount of ink 2 (water 2a) (not an excessive amount) to one side 3a of the paper-containing sheet 3 while taking into consideration the thickness T1 of the paper-containing sheet 3, the water 2a can be made to permeate the paper-containing sheet 3 from the one side 3a as shown in Figure 2(b) or Figure 2(c). Figure 2(b) shows a state in which the paper-containing sheet 3 is warped so that the one side 3a is convex, and typically, after passing through this state, the warp is eliminated as shown in Figure 2(c).

[0026] As shown in Figure 2(b), the reason the paper-containing sheet 3 warps is that as water 2a permeates from one side 3a to the other side 3b of the paper-containing sheet 3, the concentration of water 2a becomes higher (the amount of water content is greater) on one side 3a of the paper-containing sheet 3 than on the other side 3b, causing the one side 3a of the paper-containing sheet 3 to expand. As the difference in the concentration of water 2a decreases over time, the effect of the expansion of the paper-containing sheet 3 is alleviated, and the warping of the paper-containing sheet 3 is eliminated, as shown in Figure 2(c). The water 2a can be applied (applied) as droplets to one surface 3a of the paper-containing sheet 3 by, for example, supplying the ink 2.

[0027] In this embodiment, the ink 2 contains a thickener. This gives the ink 2 an appropriate viscosity, and the ink 2 filled in the pen container 1a does not leak even when the pen tip 2b is pressed, and the applied linear portion has a uniform application width according to the size of the pen tip 2b, allowing for stable application. Even if the ink 2 contains a thickener, the paper-containing sheet 3 can be folded through step (B) to form the paper-containing three-dimensional structure 5, and the desired paper-containing three-dimensional structure 5 can be formed by the portion 4 having a stable width of water concentration gradient.

[0028] In step (A), water 2 is permeated into the paper-containing sheet 3 from one surface 3a thereof to create one or more regions 4 in the paper-containing sheet 3 that have a water concentration gradient in the thickness T1 direction of the paper-containing sheet 3, as shown in Figure 2(b) or 2(c). For convenience, only one region 4 with a water concentration gradient is shown in Figure 2.

[0029] In this specification, the paper-containing sheet has a water concentration gradient in its thickness direction means that the paper-containing sheet has regions with different water contents (water concentrations) per unit area in the direction connecting both sides of the paper-containing sheet at the shortest distance. Figures 2(b) and 2(c) show a state in which the water 2 content of the paper-containing sheet 3 gradually decreases from one side 3a to the other side 3b of the paper-containing sheet 3. In this embodiment, the amount of water 2 in the paper-containing sheet 3 usually decreases in this way in the direction of penetration of the water 2, that is, in the direction from the side of the paper-containing sheet 3 to which the water 2 is attached (the one side 3a) to the opposite side (the other side 3b). However, what is shown here is one example of the change in the amount of water 2 in the paper-containing sheet 3.

[0030] In step (A), such a concentration gradient of water 2a can be easily formed by applying an appropriate but not excessive amount of ink 2 (water 2a) to one side 3a of the paper-containing sheet 3, taking into account the thickness T1 of the paper-containing sheet 3.

[0031] In Figures 2(b) and 2(c), the water 2a that has been permeated into the paper-containing sheet 3 does not reach the other surface 3b of the paper-containing sheet 3. However, in step (A), if a concentration gradient of the water 2a occurs as described above, the water 2a that has been permeated into the paper-containing sheet 3 may reach the other surface 3b of the paper-containing sheet 3, for example, as shown in Figure 3.

[0032] In step (A), one or more sites 4 having such a water concentration gradient are created in the paper-containing sheet 3.

[0033] The region 4 having a water concentration gradient is created at a position where it is desired to fold the paper-containing sheet 3. For example, when the paper-containing sheet 3 is viewed in plan from above the one surface 3a side, the shape, size and number of the region 4 having a water concentration gradient are determined according to the intended paper-containing three-dimensional structure.

[0034] In step (A), the amount of water 2a to be permeated into the paper-containing sheet 3 (adherent amount) is not particularly limited as long as it does not impair the effects of the present invention. 2 It is preferable to set the thickness to 5 to 25 g / m 2 By setting the amount of water 2a to be permeated per unit area of ​​the paper-containing sheet 3 in this range, the paper-containing sheet 3 can be folded more efficiently.

[0035] In step (A), when the region 4 having a water concentration gradient is formed in the paper-containing sheet 3 in the form of a solid line, dotted line, or other line, the line width is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 1 to 50 mm, and more preferably 3 to 30 mm. By having the line width in this range, the paper-containing sheet 3 can be folded autonomously more efficiently.

[0036] In step (A), when the portion having a water concentration gradient is linear, the line width may change over time. In this embodiment, unless otherwise specified, the line width means a constant value of the line width when the line width does not change over time, and means a maximum value of the line width when the line width changes over time.

[0037] For example, as shown in Fig. 2(b), when the line width is maximum when the paper-containing sheet 3 is warped, it is preferable that the line width W1 shown in Fig. 2(b) is within the above-mentioned numerical range. On the other hand, as shown in Fig. 2(c), when the line width is maximum when the paper-containing sheet 3 is not warped, it is preferable that the line width W1 shown in Fig. 1(c) is within the above-mentioned numerical range. The line width can be measured, for example, by looking down from above the one surface 3a of the paper-containing sheet 3 in a plan view.

[0038] In step (A), the site 4 having a water concentration gradient can be produced in any shape, such as a solid line, a dotted line, or a dashed dotted line, in the paper-containing sheet 3. Even in the case of a dotted line, dashed dotted line, or the like, the site 4 having a water concentration gradient can be easily produced as a paper-containing three-dimensional structure 5 having creases, that is, a so-called origami-style structure, as long as the individual local sites having a water concentration gradient are close to each other and are intermittently connected to each other in a direction parallel to the one surface 3a of the paper-containing sheet 3.

[0039] In this embodiment, the area 4 having a water concentration gradient may be formed by combining two or more different shapes or patterns, such as solid lines, dotted lines, and dashed dotted lines, and in cases where there are multiple areas forming creases, the line widths may be different in these multiple areas.

[0040] In step (A), two or more regions having a water concentration gradient with different permeation amounts of water 2a may be produced in a direction parallel to the one surface 3a of the paper-containing sheet 3 (in other words, the surface direction). By changing the way of supplying the ink 2 by changing the type of the application-type container 1, the pen tip, the composition of the ink 2, etc., and changing the amount of water 2a attached to the surface 3a of the paper-containing sheet 3, two or more regions having a water concentration gradient with different permeation amounts of water 2a can be produced. By producing the regions having different permeation amounts of water 2a in this way, the folding speeds at these regions can be made different in step (B) described later based on the difference in the permeation amounts of water 2a. And by making the folding speeds different in this way, a paper-containing three-dimensional structure 5 with a more complicated shape can be produced. Furthermore, a paper-containing three-dimensional structure 5 with different folding angles at these regions can be produced.

[0041] In step (A), the pressure, temperature, and relative humidity of the environment when the ink 2 (water 2a) is applied to the paper-containing sheet 3 and allowed to permeate, and the time from when the ink 2 (water 2a) is applied to the paper-containing sheet 1 to when the ink is allowed to permeate, can be arbitrarily set within a range that does not impair the effects of the present invention, depending on the conditions, and are not particularly limited. The process can be suitably carried out under atmospheric pressure indoors or outdoors.

[0042] In step (A), the pressure of the environment when the water 2a is applied to the paper-containing sheet 3 and is allowed to permeate the paper-containing sheet 3 is 0 to 1.0×10 12 Pa is preferably 1.0×10 2 ~1.0×10 9 Pa is more preferably 1.0×10 6 ~1.0×10 7 It is more preferable that the pressure is 10 Pa, and may be normal pressure (atmospheric pressure), for example. Under such pressure conditions, the water 2a can be permeated into the paper-containing sheet 3 more satisfactorily.

[0043] In the step (A), the temperature at which the water 2a is applied to the paper-containing sheet 3 and allowed to penetrate is -273.15 to 1.0 × 10 5 ° C., and preferably −10 to 1.0×10 3 °C, more preferably 1.0 × 10 -12 It is more preferable that the temperature is in the range of 10 to 100° C., and may be, for example, 10 to 35° C. Under such temperature conditions, the water 2a can be permeated into the paper-containing sheet 3 more satisfactorily.

[0044] In step (A), the relative humidity when the water 2a is applied to and permeated into the paper-containing sheet 3 is preferably 0 to 100%, more preferably 10 to 80%, and may be, for example, any of 20 to 65% and 20 to 40%. Under such relative humidity conditions, the water 2a can be more effectively permeated into the paper-containing sheet 3.

[0045] In step (A), the time for permeating the water 2a from the application to the paper-containing sheet 3 can be set arbitrarily depending on other conditions at this time, and is not particularly limited. For example, the time may be within 100,000 minutes.

[0046] In step (A), it is preferable to set two or more selected from the group consisting of the pressure, temperature, relative humidity and time of the environment when water 2a is adhered to the paper-containing sheet 3 and then allowed to penetrate to the above-mentioned conditions, and all of the pressure, temperature, relative humidity and time of the environment when water 2a is adhered to the paper-containing sheet 3 and then allowed to penetrate may be set to the above-mentioned conditions. <Process (B)>

[0047] After the step (A), the paper-containing sheet having the water concentration gradient is dried in the step (B). As a result, for example, as shown in Fig. 4(a), the paper-containing sheet 3 begins to bend so that one surface 3a becomes concave at the site 4 having the water concentration gradient, and as the drying (in other words, the removal of water 2a) progresses, the bending angle increases, and when the drying is completed, for example, as shown in Fig. 4(b), the intended paper-containing three-dimensional structure 5 is formed.

[0048] In this embodiment, by drying the paper-containing sheet 3 having a water concentration gradient (in other words, having an area 4 having a water concentration gradient), the paper-containing sheet 3 is caused to autonomously fold at the area 4' that previously had the water concentration gradient. In the paper-containing sheet 3, the cellulose molecules are initially bonded to each other by hydrogen bonds.

[0049] In the above-mentioned step (A), when ink 2 is applied from a coating container 1 to a paper-containing sheet 3 and water 2a is allowed to penetrate, one side 3a expands as explained above. In the paper-containing sheet 3, the water molecules break the hydrogen bonds between cellulose molecules, resulting in a state in which the water molecules are interposed between the cellulose molecules, and it is presumed that intermolecular bonds of cellulose molecule-water molecule-cellulose molecule are formed.

[0050] On the other hand, the paper-containing sheet 3 is manufactured in a state in which distortion has been generated by an external force due to its manufacturing method. When step (B) is performed on such a paper-containing sheet 3 after step (A), as the water in the paper-containing sheet 3 is reduced by drying, the paper-containing sheet 3 becomes stable with the distortion reduced or eliminated from the initial state, and it is presumed to shrink more than before the water 2a penetrated. It is presumed that the contraction force generated at this time causes the paper-containing sheet 3 to autonomously bend at the portion 4' that had the water concentration gradient, as shown in Figure 4(b) for example.

[0051] In step (B), the paper-containing sheet 3 is folded autonomously with the side having a higher concentration of water 2a (i.e., one side 3a) of both sides (i.e., one side 3a and the other side 3b) of the paper-containing sheet 3 facing inward (i.e., the other side 3b facing outward).

[0052] When the paper-containing sheet 3 is folded autonomously, the folded portion does not necessarily have a clear crease, and the surface of the folded portion is often curved. Even if the surface of the folded portion is curved from the boundary with the portion 4' of the paper-containing sheet 3 that had a water concentration gradient, a crease is formed if both sides through the boundary have an angle. When one side of the paper-containing sheet 3 through the portion 4' that had a water concentration gradient is used as a reference and the other side stands up with the coated surface (one side 3a) of the paper-containing sheet 3 on the inside, a crease is formed, and the angle is not particularly limited, for example, from more than 0° to 180° where the one side is bent to the other side. <Coating type container>

[0053] The applicator container 1 of this embodiment is characterized in that the ink 2 contains a thickener. By containing a thickener, the ink 2 thickens and has a suitable viscosity, and the thickening prevents leakage, etc., provides a stable writing experience, and makes it easy to bend the paper-containing sheet 3. In addition, the applicator container 1 can be used to apply the ink 2, allowing writing to be freely customized, so that various application shapes that one has in mind can be easily realized.

[0054] The container and ink supply unit in the application-type container 1 of this embodiment are not particularly limited in type as long as they can apply the required amount of liquid ink 2 as an application-type container and can deform the paper-containing sheet 3, and for example, various conventionally known ones can be used. Specific examples include writing-type applicators such as valve pens, batting pens, and brush pens, and transfer-type applicators such as containers with sponge filters, roller containers, and stamps. Figure 5 shows examples of these, where (a) is a valve-type pen, (b) is a batting pen, (c) is a brush pen, (d) is a container with sponge filters, (e) is a roller container, and (f) is a stamp.

[0055] Of these, pen-type writing applicators are preferably used, and among these, valve-type pens are preferred because they can apply ink in a wide and constant width and can supply a large amount of ink 2.

[0056] The thickener contained in ink 2 is not particularly limited, but examples thereof include thickening polysaccharides such as xanthan gum, carboxymethylcellulose, sodium alginate, guar gum, carrageenan, lobster bean gum, and gum arabic, cellulose nanofiber, and polyacrylic acid.

[0057] It is considered that the ink 2 has an appropriate viscosity depending on the type of application type container 1, but the appropriate viscosity tends to be higher for valve pens and brush pens which supply a large amount of ink, and the viscosity at 25°C measured with a Zahn cup is preferably 60 to 700 cps, and more preferably 90 to 500 cps.

[0058] For spool-type pens that supply a small amount of ink, the appropriate viscosity tends to be lower, and is preferably 10 to 80 cps, and more preferably 10 to 50 cps.

[0059] The content of the thickener in the ink 2 is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, based on the total amount of the base liquid components such as water and lower alcohols, so as to obtain the above-mentioned viscosity range. The upper limit of the content of the thickener depends on the type of the application-type container 1 as described above, but is generally preferably 1% by mass or less.

[0060] The liquid component serving as the base of the ink 2 must be water, and other liquid components, such as alcohol miscible with water, may be used in combination in order to improve the ink's wettability. Examples of alcohol include lower alcohols such as 2-propanol. Water 2a is essential for deforming the paper, whereas alcohol can improve the ink's wettability. The ratio of water to alcohol is not particularly limited, but in order to achieve both foldability and improved ink wettability, a mass ratio of 97:3 to 70:30 is preferred.

[0061] In the application-type container 1 of this embodiment, other components than those described above may be added to the ink 2 within a range that does not impair the effects of the present invention. The other components are not particularly limited, but examples thereof include colorants such as dyes, and electrolytes such as salts that change the penetration of water. These may be used alone or in combination of two or more. <Paper-containing sheet>

[0062] The paper-containing sheet 3 is a sheet made of paper (i.e., a paper sheet) or a sheet mainly composed of paper, and contains cellulose as a main component. Since a water concentration gradient is required to deform the paper-containing sheet 3, the paper-containing sheet 3 is not particularly limited as long as it is a paper that has a concentration gradient. A specific example of the sheet made of paper (paper sheet) is tracing paper. A paper-based sheet contains paper and other ingredients in addition to the paper. The other components can be arbitrarily selected depending on the purpose within a range that does not impair the effects of the present invention. Specific examples of the other components include resins and silica gel.

[0063] The other components contained in the sheet containing paper as a main component may be one type only, or two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0064] In a sheet whose main component is paper, the ratio of the content of the other components to the total mass of the sheet ([amount of the other components in the sheet whose main component is paper (parts by mass)] / [total mass of the sheet whose main component is paper (parts by mass)]×100) is preferably 40% by mass or less, and may be, for example, 30% by mass or less, 20% by mass or less, 10% by mass or less, or 5% by mass or less. Having the ratio be less than the upper limit allows the paper-containing sheet 3 to be folded more efficiently.

[0065] On the other hand, the ratio may be more than 0% by mass, for example, 1% by mass or more. The higher the lower limit of the ratio, the higher the effect obtained by including the other components.

[0066] The paper-containing sheet (sheet made of paper, sheet mainly composed of paper) 3 may be one layer (single layer) or may be two or more layers. When the paper-containing sheet is made of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited.

[0067] In this specification, "multiple layers may be the same or different from one another" means "all layers may be the same, all layers may be different, or only some layers may be the same", and further, "multiple layers are different from one another" means "at least one of the constituent materials and thicknesses of each layer is different from one another".

[0068] The thickness T1 of the paper-containing sheet 3 can be selected arbitrarily depending on the purpose. -6 ~1.0×10 4 It is preferable that T1 is in the range of 1 to 1000 μm, and more preferable that it is in the range of 1 to 1000 μm. When T1 is in this range, the paper-containing sheet 1 can be folded with higher accuracy.

[0069] Here, "the thickness of the paper-containing sheet" means the thickness of the entire paper-containing sheet, and for example, the thickness of a paper-containing sheet consisting of multiple layers means the thickness of all layers that make up the paper-containing sheet.

[0070] The shape of the paper-containing sheet 3 is not particularly limited as long as it is sheet-like, and can be arbitrarily selected according to the structure of the intended paper-containing three-dimensional structure, for example, the structure of the paper-containing three-dimensional structure shown in Figures 6 to 9. <Coating container set for producing paper-containing three-dimensional structures>

[0071] The coated container 1 can be sold as a product independent of the paper-containing sheet 3 as a coated container 1 for producing a paper-containing three-dimensional structure, but the coated container 1 and the paper-containing sheet 3 of this embodiment may be a coated container set for producing a paper-containing three-dimensional structure 5. For example, a specific coated container 1 and a specific paper-containing sheet 3 are associated with each other and sold as a product for producing a paper-containing three-dimensional structure 5. More specifically, a specific coated container 1 and a specific paper-containing sheet 3 are sold as the same product, or a specific coated container 1 and a specific paper-containing sheet 3 are associated with each other and sold separately, and when the ink 2 in the coated container 1 runs out, the coated container 1 or the ink 2 to be filled is purchased, and when the paper-containing sheet 3 runs out, the specific paper-containing sheet 3 is purchased, or a separate series of paper-containing sheets 3 is purchased to produce a separate paper-containing three-dimensional structure. <Examples of paper-containing three-dimensional structures> FIG. 6 is a perspective view that shows a schematic example of the paper-containing sheet used in this embodiment and the intended paper-containing three-dimensional structure. The paper-containing sheet 3 shown in FIG. 6(a1) has a rectangular planar shape, and a U-shaped cut 6 is provided in the center.

[0072] Step (A) is performed by applying ink 2 to a portion of one surface 3a of a paper-containing sheet 3, which corresponds to the base end of the U-shaped incision 6, using an application type container 1, thereby creating a portion 4 having a water concentration gradient, as shown in Figure 6(a1).

[0073] Next, by carrying out step (B), the paper-containing sheet 3 is autonomously folded toward the one surface 3a at the portion 4' where the water concentration gradient was present. As a result, a paper-containing three-dimensional structure 5 can be produced in which the paper pieces partially cut at the U-shaped cuts 6 stand up, as shown in FIG. 6(b1).

[0074] The paper-containing sheet 3 shown in FIG. 6(a2) has a rectangular planar shape, and has two parallel cuts 6 of the same length provided from one longitudinal end to the center.

[0075] Step (A) is performed by applying ink 2 to the area of ​​one side 3a of the paper-containing sheet 3 that corresponds to the base ends of two parallel incisions 6 using an application-type container 1, thereby creating an area 4 having a water concentration gradient, as shown in Figure 6(a2).

[0076] Next, by carrying out step (B), the paper-containing sheet 3 is autonomously folded toward the one surface 3a at the portion 4' where the water concentration gradient was present. As a result, a paper-containing three-dimensional structure 5 can be produced in which the paper pieces partially cut by the two parallel cuts 6 stand up, as shown in FIG. 6(b2).

[0077] In this way, when cutting a portion of the paper-containing sheet 3 with a cut 6 and partially folding the sheet, the cut portions of the paper-containing sheet 3 come into contact with each other, and the cut 6 will catch and hinder bending. Therefore, in the example of FIG. 6, the cut is made to have a certain width, so that the paper-containing sheet 3 does not catch on each other and can be easily folded. Laser processing is preferred as a means of cutting the cut 6 with a certain width. Laser processing can control the width of the cut 6, and can be adjusted so that the cut surfaces do not come into contact. It is preferred that the width of the cut 6 is 0.2 mm or more, as this does not hinder bending. FIG. 7 is a cross-sectional view that illustrates another example of a paper-containing sheet in which a water concentration gradient has been created, and a target paper-containing three-dimensional structure in this embodiment.

[0078] The paper-containing sheet 3 shown in Figure 7(a) has a rectangular planar shape, and by applying ink 2 using an application type container 1 and performing process (A), regions 4 having a linear water concentration gradient are created in two places on one surface 3a, and regions 4 having a linear water concentration gradient are also created in three places on the other surface 3b.

[0079] Next, by carrying out step (B), the paper-containing sheet 3 is autonomously folded toward one surface 3a at a portion 4' that previously had a water concentration gradient on one surface 3a, and is autonomously folded toward the other surface 3b at a portion 4' that previously had a water concentration gradient on the other surface 3b. In this manner, a corrugated paper-containing three-dimensional structure 5 can be produced as shown in FIG. 7(b).

[0080] In this manner, in this embodiment, one or more regions having a water concentration gradient may be created on each of both sides (the one side and the other side) of the paper-containing sheet.

[0081] FIG. 8 is a cross-sectional view that shows a schematic diagram of another example of a paper-containing sheet in which a portion having a water concentration gradient has been produced, and a target paper-containing three-dimensional structure in this embodiment.

[0082] 8(a) has a rectangular planar shape, and a large number of linear regions 4 having a water concentration gradient are formed parallel to one another with small gaps on one side 3a of the paper-containing sheet 3 by applying ink 2 using a coating container 1 and carrying out step (A). In contrast, no regions having a water concentration gradient are formed on the other side 3b of the paper-containing sheet 3.

[0083] Next, by carrying out the step (B), the paper-containing sheet 3 is autonomously folded towards the one surface 3a at the portion 4' that had the water concentration gradient.

[0084] As a result of the above, the paper-containing sheet 3 now has the same number of regions 4' that had a water concentration gradient as the regions 4 that have a water concentration gradient, so that a semi-cylindrical paper-containing three-dimensional structure 5 can be produced, as shown in Figure 8(b).

[0085] In addition, since the folding angle of the paper-containing sheet 3 can be adjusted by adjusting the amount of water permeation into the paper-containing sheet 3 or the width of the region 4 having a water concentration gradient, it is possible to form the paper-containing three-dimensional structure 5 into a shape other than a semi-cylindrical shape. For example, by increasing the amount of water permeation or widening the width of the region 4 having a water concentration gradient compared to the case of Fig. 8(b), it is possible to manufacture a cylindrical paper-containing three-dimensional structure or a paper-containing three-dimensional structure wound into a roll.

[0086] As described above, in this embodiment, the arrangement of the portions having a water concentration gradient in the paper-containing sheet and the autonomous folding method of the paper-containing sheet are not limited to the case of autonomously folding in a straight line.

[0087] So far, generally, areas in a paper-containing sheet having a water concentration gradient have been shown to have a linear shape, but as long as a water concentration gradient can be formed, the shape of the area having a water concentration gradient may be, for example, any filled shape that has a surface area clearly larger than that of a line (for example, a polygon, a circle, an ellipse, an irregular shape that does not fall into any of these categories, and a composite shape that combines one or more of these shapes).

[0088] FIG. 9 is a perspective view that shows a schematic example of the paper-containing sheet used in this embodiment and the intended paper-containing three-dimensional structure.

[0089] The paper-containing sheet 3 shown in FIG. 9(a) has a cross shape with one of the two sides being longer.

[0090] When the paper-containing sheet 3 is regarded as a joint of six square sheets of the same size, the ink 2 is applied to the paper-containing sheet 3 using the application type container 1 to carry out step (A), and regions 4, 4, ... having a water concentration gradient can be created in the regions corresponding to the joints of these square sheets, as shown in Figure 9(B). At this time, all of these regions 4, 4, ... having a water concentration gradient can be created by permeating water from the same side of the paper-containing sheet 3, i.e., from one side 3a.

[0091] Next, by carrying out the step (B), the paper-containing sheet 3 is autonomously folded towards the one surface 3a at the sites 4', 4', . . . which had the water concentration gradient. In this manner, a cubic paper-containing three-dimensional structure 5 can be produced as shown in FIG. 9(c).

[0092] According to the coated container, coated container set for producing a paper-containing three-dimensional structure, and manufacturing method of a paper-containing three-dimensional structure of the present embodiment described above, paper can be easily bent by applying ink using origami techniques, providing a stable writing experience.

[0093] Furthermore, unlike conventional methods, it is not necessary to supply energy such as electric current or heat to the paper-containing sheet, and there is no need to modify the paper with a special material, which provides the advantage of being highly practical. Taking advantage of these characteristics, the manufacturing method of this embodiment is useful for applications such as educational toys, paper crafts, decorative items, and folding sheets. EXAMPLES

[0094] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0095] In the following tests, the coatability was evaluated mainly from the viewpoints of a constant coating width, a thickening effect that allows coating without leakage, and a constant coating without smearing and little variation. Additionally, whether the paper base material could be folded and its deformation characteristics were evaluated from the deformation angle of the paper base material, and the amount of change in bending of the paper base material relative to the coating width, coating amount, viscosity, etc.

[0096] <Comparative Examples 1 to 6: Evaluation without the addition of thickener> The base material is tracing paper (GL tracing, manufactured by Mitsubishi Paper Mills, basis weight 65g / m 2 , 95g / m 2 , 135g / m 2 Three types of fluororesin were used. The pen container used was a valve-type pen container C1-10 (lead size: 15 mmφ).

[0097] Each ink was poured into a pen container and applied in a straight line from one side to the other side of a 50 mm-wide tracing paper with a pen. The straight line was applied in the width direction or flow direction (fiber direction) of the tracing paper.

[0098] After that, the coating width (mm, size relative to the core size) and coating amount (g / m 2 The ink viscosity (calculated from the ink mass) and bending angle (deformation angle, average value at several points in the application direction) were measured, and the application properties and the degree of bending in relation to the type of ink, thickness of the tracing paper, and thickness of the applied line were compared and evaluated.

[0099] First, when investigating the causes of paper deformation in Non-Patent Document 1, tests were conducted using water and a mixture of water and alcohol (90% water by mass + 10% alcohol by mass) as low-viscosity aqueous liquids without added thickeners used as ink for inkjet printers. 2-propanol was used as the alcohol. Evaluations using water as ink were conducted at an air temperature of 20.0°C and a humidity of 73%, and the results are shown in Table 1 and Figure 10(a). Evaluations using a mixture of water and alcohol as ink were conducted at an air temperature of 20.5°C and a humidity of 65%, and the results are shown in Table 2 and Figure 10(b).

[0100] [Table 1]

[0101] [Table 2]

[0102] From Table 1 and Figure 10(a), deformation of the paper substrate was confirmed when using only water, and even when using an ink pen type, the same tendency as the printing method (inkjet) in Non-Patent Document 1 was confirmed. However, the coating width was not stable, and liquid leakage and repelling on the coated surface could be observed, so it was not suitable for a pen. As shown in the photo on the right of Figure 10(a), when the pen tip is pressed while supplying liquid, liquid leaks.

[0103] From Table 2 and Figure 10(b), when the aqueous liquid to which alcohol, which was used in Non-Patent Document 1 to improve printability, was added was used as ink, a similar trend to that of the printing method (inkjet) in Non-Patent Document 1 was confirmed.

[0104] However, similar to the case of water, the application width was not stable, and the pen tip was not suitable for dispensing the liquid because leakage of the liquid was observed when the tip was pressed down, as shown in the right photo of Figure 10(b).

[0105] <Examples 1 to 6 and Comparative Examples 7 and 8: Evaluation of Addition of Thickener> When using water or water and alcohol, the ink leaks out because too much of the solution is supplied to the pen tip (low ink viscosity). It is thought that adjusting the viscosity will allow the ink to be supplied from the pen tip stably. Therefore, we investigated whether adding a thickener to the ink would stabilize the application and whether adding a thickener would have any effect on bending. The base material has a basis weight of 135g / m, which makes it easy to check the angle change. 2 Tracing paper (GL Tracing, manufactured by Mitsubishi Paper Mills, Ltd.) was used.

[0106] The ink uses water and a mixture of water and alcohol (90% water by mass + 10% alcohol by mass) as the base liquid, and xanthan gum as the thickener. Xanthan gum is a hydrophilic colloid that acts to stabilize water systems by thickening, stabilizing suspensions, and stabilizing emulsions, and has extremely high pseudoplastic properties.

[0107] The ink was prepared by stirring the base liquid and adding a prescribed amount of a thickener for adjusting the viscosity in Examples 1 to 6. The viscosity of the ink was measured using a Zahn cup at 25° C. and converted into CPS viscosity.

[0108] Other than the above, the pen container, application method, etc. were measured in the same manner as in Comparative Examples 1 to 6, and the application property and the degree of bending of the tracing paper were evaluated in comparison with cases where ink without added thickener was used (Comparative Examples 7 and 8).

[0109] The evaluation of ink containing water and thickener was performed at a temperature of 21.0°C, humidity of 30%, and drying time of 10 minutes, and the results are shown in Table 3 and Figure 11(a). The evaluation of ink containing water and 2-propanol was performed at a temperature of 21.0°C, humidity of 65%, and drying time of 6 minutes, and the results are shown in Table 4 and Figure 11(b).

[0110] [Table 3]

[0111] [Table 4]

[0112] As for the deformation state of the paper substrate, from Tables 3 and 4 and Figures 11(a) and (b), almost no difference in the deformation angle due to the amount of thickener added was confirmed. Since the effect of the thickener is small when a constant amount is applied, it was confirmed that the application stability with the pen can be improved by adjusting the viscosity.

[0113] Regarding the applicability, from Tables 3 and 4 and Figures 11(a) and (b), in Comparative Examples 7 and 8, when the pen tip was pressed during ink supply, leakage was noticeable. In Examples 1 and 4, where 0.1% by mass of thickener was added (viscosity 50 cps), the problem was improved, but some leakage was observed. In Examples 2 and 5, where 0.25% by mass of thickener was added (viscosity 85 cps), the pen tip was stable without leakage. In Examples 3 and 6, where 0.5% by mass of thickener was added (viscosity 300 cps or more), no leakage was observed, but in Examples 3 and 6, a tendency was observed in which the ink was less likely to penetrate into the felt of the pen tip of the valve-type pen container.

[0114] <Examples 7 to 10 and Comparative Examples 9 to 12: Comparative evaluation of pen tip thickness and pen case type> We confirmed that valve-type pens can be used to apply paint stably by adjusting the viscosity regardless of the thickness of the pen tip.

[0115] As in Examples 1 to 6 and Comparative Examples 7 and 8, the base material had a basis weight of 135 g / m2, which allows easy confirmation of angle change. 2 The ink used was a tracing paper (GL Tracing, manufactured by Mitsubishi Paper Mills) with water and a mixture of water and alcohol (90% water by mass + 10% alcohol by mass) as the base liquid, and xanthan gum as the thickener. The viscosity was set to 0.25% by mass (110 cps), which was the most stable condition for application.

[0116] The pen containers used were valve-type pen containers A1-10 (lead size: 2 mmφ) and B1-10 (lead size: 5 mmφ).

[0117] Other than the above, the ink preparation and the method of application to the paper substrate were the same as in Examples 1 to 6 and Comparative Examples 7 and 8, and measurements were performed, and the application property and the degree of bending of the tracing paper were compared and evaluated in comparison with the case where ink without added thickener was used (Comparative Examples 9 and 10). The results are shown in Table 5 and Figure 12(a).

[0118] [Table 5]

[0119] From Table 5 and Figure 12 (a), in Comparative Examples 9 and 10, when the pen tip was pressed during ink supply, leakage was noticeable. In Examples 7 and 8, in which 0.25 mass% thickener was added (viscosity 85 cps), the pen tip was stable without leakage, and deformation of the paper substrate was also confirmed. Thus, regardless of the thickness of the pen tip, stable application was possible by adjusting the viscosity, and deformation of the paper substrate was also confirmed.

[0120] Next, an evaluation was conducted to see whether there was any change in the applicability using a brush pen and a cotton-filled container, which have a different ink supply method from the valve type.

[0121] As in Examples 1 to 6 and Comparative Examples 7 and 8, the base material had a basis weight of 135 g / m2, which allows easy confirmation of angle change. 2 The tracing paper used was GL Tracing, manufactured by Mitsubishi Paper Mills, and the ink used was a mixture of water and alcohol (90% by mass water + 10% by mass alcohol) as the base liquid, with xanthan gum used as the thickener.

[0122] The pen containers used were a chisel core with a batting tip (3 mm tip) and a large brush pen container (15 mm tip). With the brush pen container, ink was supplied to the tip by pushing the pen body, while with the batting pen container, ink was supplied to the tip after waiting until the ink had soaked into the batting. A straight line was applied with the pen across the width of a 50 mm wide tracing paper from one side to the other. The straight line was applied across the width or flow direction (fiber direction) of the tracing paper. With the brush pen, ink was applied to a width of 10 mm.

[0123] Other than the above, measurements were performed in the same manner as in Examples 1 to 6 and Comparative Examples 7 and 8, and the coating properties and degree of bending of the tracing paper were compared and evaluated in comparison with the case where ink without added thickener was used (Comparative Examples 11 and 12). The evaluation was performed at a temperature of 21.0°C, humidity of 40%, and drying time of 6 minutes, and the results are shown in Table 5 and Figure 12(a).

[0124] [Table 6]

[0125] For the brush pen, Comparative Example 11, which did not add a thickener, supplied a large amount of liquid, and the liquid bled from the tip of the brush. Example 9, which added a thickener, was stable and could be applied, and deformation of the paper base material was also confirmed. For the padded pen, Comparative Example 12, which did not add a thickener, was able to be applied, but the application was slightly poor. Example 10, which added a thickener, was stable and could be applied, and deformation of the paper base material was also confirmed.

[0126] For brush pens and cotton-filled pens, appropriate viscosities were found for each container. For brush pens, as the supply volume is large, a higher viscosity than for valve-type containers makes it less likely to leak and allows for more stable application. For cotton-filled pens, slightly higher viscosity allows the paint to soak into the cotton just right and allows for more stable application. It was confirmed that stable application is possible by adjusting the viscosity, regardless of the pen container.

[0127] <Examples 11 to 13: Comparative evaluation of types of thickeners and when dyes are added> Regardless of the type of thickener, an evaluation was conducted by changing the type of thickener to see whether or not stable application was possible by thickening the composition.

[0128] Carboxymethylcellulose (CMC) was used as a thickening agent. CMC dissolves in cold and hot water to form a viscous colloidal solution with almost no taste or odor. It has the characteristics of exhibiting high viscosity at low concentrations, and the viscosity of the aqueous solution changes little over time, remaining stable for long periods of time.

[0129] As in Examples 1 to 6 and Comparative Examples 7 and 8, the base material had a basis weight of 135 g / m2, which allows easy confirmation of angle change. 2 The ink was made using tracing paper (GL Tracing, manufactured by Mitsubishi Paper Mills) and water and a mixture of water and alcohol (90% water by mass + 10% alcohol by mass) as the base liquid. The base liquid was stirred and 0.8% by mass of CMC was added as a thickener to adjust the viscosity, to produce the ink.

[0130] Other than the above, the pen container, application method, etc. were the same as in Examples 1 to 6 and Comparative Examples 7 and 8, and measurements were made to compare the application properties and the degree of bending of the tracing paper. The evaluation was performed at a temperature of 21.0°C and a humidity of 40%, and the results are shown in Table 7 and Figure 13(a).

[0131] [Table 7]

[0132] The pen tip during ink supply was able to apply ink stably, and the paper substrate was also able to deform. Regardless of the type of thickener, ink can be applied stably by thickening the ink, and the paper substrate can also be deformed.

[0133] As a commercial product, colored inks are more fun because it is easier to see where they have been applied. Therefore, we checked whether inks with dyes added as colorants had any effect on the bending of the paper.

[0134] As in Examples 1 to 6 and Comparative Examples 7 and 8, the base material had a basis weight of 135 g / m2, which allows easy confirmation of angle change. 2 The ink used was a tracing paper (GL Tracing, manufactured by Mitsubishi Paper Mills) with water and a mixture of water and alcohol (90% water by mass + 10% alcohol by mass) as the base liquid, and xanthan gum as the thickener. Kayarus Rose FR (manufactured by Nippon Kayaku Co., Ltd.) was used as the dye. The base liquid was stirred, and the dye was added to the solution of water + alcohol + thickener (0.25% by mass) so that the amount was 1% by mass, to prepare the ink.

[0135] Other than the above, the pen container, application method, etc. were the same as in Examples 1 to 6 and Comparative Examples 7 and 8, and measurements were performed, and the application property and the degree of bending of the tracing paper were compared and evaluated in comparison with the case where ink without added dye was used (Example 12). The results are shown in Table 8 and Figure 13(b).

[0136] [Table 8]

[0137] The pen tip was stable when ink was being supplied, and deformation of the paper substrate was also confirmed, confirming that it was possible to add dye. It was also suggested that the dye may reduce the deformation angle by inhibiting the penetration of water. When using colored ink, it is recommended to apply a larger amount in order to promote deformation of the paper substrate. [Explanation of symbols]

[0138] 1. Coating container 1a Pen holder 1b Pen tip 2 Ink 2a Water contained in ink 3. Paper-containing sheets 3a One side 3b The other side 4. Areas with water concentration gradient 4' Site with water concentration gradient 5 Three-dimensional structure containing paper 6 Laser cutting T1 Paper-containing sheet thickness W1 Line width of the area with water concentration gradient

Claims

1. A paper-containing sheet is made of paper or contains paper as a main component, and ink is applied to one side of the paper-containing sheet to cause water to penetrate the paper-containing sheet from the one side, thereby creating one or more regions in the paper-containing sheet that have a water concentration gradient in the thickness direction of the paper-containing sheet; A coating type container for producing a paper-containing three-dimensional structure by drying the paper-containing sheet having the water concentration gradient, and autonomously folding the paper-containing sheet at the portion where the water concentration gradient was present, The ink is a spreadable container containing water and a thickener.

2. A coating type container according to claim 1, A paper-containing sheet is made of paper or contains paper as a main component, and ink is applied from the application type container to one side of the paper-containing sheet, thereby causing water to permeate the paper-containing sheet from the one side, and creating one or more regions in the paper-containing sheet having a water concentration gradient in a thickness direction of the paper-containing sheet; and a paper-containing sheet capable of autonomously folding the paper-containing sheet at the portion that had the water concentration gradient by drying the paper-containing sheet in a state having the water concentration gradient to produce a paper-containing three-dimensional structure.

3. A method for producing a paper-containing three-dimensional structure, which is formed by folding a paper-containing sheet made of paper or containing paper as a main component, comprising: a step (A) of applying ink containing water and a thickener to one side of the paper-containing sheet using a coating container having the ink therein, thereby causing water to penetrate into the paper-containing sheet from one side thereof, thereby creating one or more portions on the paper-containing sheet having a water concentration gradient in the thickness direction of the paper-containing sheet; and (B) drying the paper-containing sheet in a state having the water concentration gradient, thereby causing the paper-containing sheet to autonomously fold at the portion that had the water concentration gradient to produce a paper-containing three-dimensional structure.

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