JPH02193154A - Sheet for stereoscopic image - Google Patents

Abstract

PURPOSE:To enable uniform transfer of a hot stamp foil colorant layer by coating the surface of a heat expansive coating layer with a resin film composed essentially of polyvinyl alcohol well adhesive to a molten toner. CONSTITUTION:The heat expansive coating layer 12 is formed by microencapsulating a low b.p. volatile material with a thermoplastic resin, dispersing the obtained fine heat expansive balls 13 into a binder resin made of a thermoplastic resin, and coating the surface of a base sheet 11 with the binder resin containing the balls 13. The layer 12 is further coated with the film 14 of the resin composed essentially of the polyvinyl alcohol. Therefore, the surface of the toner image 15 is kept smooth, even when the parts of the toner image are raised by light irradiation treatment, thus permitting the colorant layers 33, 34 of the hot stamp foil S to be uniformly transferred and prevented from attaching to parts except the toner image parts, and water resistance to be enhanced by using the polyvinyl alcohol having a molecular weight of 500-1,000 and a saponification degree of >=99mol%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sheet for stereoscopic images, which is provided with a thermally expandable coating layer on the sheet surface and is capable of forming images with a three-dimensional effect.

[Conventional technology]

As a method of forming a three-dimensional image on a sheet, physical methods such as pressing using a matrix are widely used, and in recent years, low boiling point vaporization, as shown in the cross-sectional configuration in Figure 1 (a) A method using a thermally expandable sheet P in which a coating layer 2' containing thermally expandable microspheres 3 in which a substance is microencapsulated in a thermoplastic resin is provided on a base sheet 1 is used (Japanese Patent Publication No. 1983-1999). Publication No. 35359, JP-A-55-101
(See Publication No. 954).

In order to form a three-dimensional image using the thermally expandable sheet described above, a desired image is formed on the sheet using a material with good light absorption. For example, an image is formed using black toner using an ordinary electrophotographic copying machine.

FIG. 1(b) shows a state in which an image 4 of black toner is formed on the coating layer 2 of the thermally expandable sheet P. Next, the surface of this sheet P is irradiated with light, and due to the difference in light absorption characteristics, only the image area 4 formed by the black toner is selectively heated to expand the thermally expandable microspheres 3, and from the sheet surface. Raise it to form a three-dimensional image (see Figure 1(c))
.

[Problem to be solved by the invention]

Conventionally, three-dimensional images made of thermally expandable sheets have been mainly used as Braille sheets for visually impaired people, and in this case, a single color was sufficient. On the other hand, sheets with three-dimensional images formed on them are expected to be used as advertising media, picture books, and other applications for people, but in this case it is essential that the three-dimensional images be colored. However, because color toner has lower light absorption efficiency than black toner, it does not generate enough heat to expand the thermally expandable microspheres on the sheet, making it difficult to form images with a three-dimensional effect. there were.

To solve this problem, we formed an image with black toner, irradiated it with light to raise the image area, and then heat-pressed a film with a coloring material layer called hot stamp foil onto the sheet, and then applied heat to the raised toner image. A method of transferring a coloring material layer has been proposed, but in this method, the surface of the raised toner image becomes a rough surface, and the coloring material layer cannot be transferred uniformly. However, there was a problem in that the coloring material layer adhered and stained the sheet surface. .

[Means to solve the problem]

In order to solve the above problems, this invention further covers the thermally expandable coating layer of the thermally expandable sheet with a film of polyvinyl alcohol resin, and on the base sheet,
Thermally expandable microspheres obtained by microencapsulating a low boiling point volatile substance with a thermoplastic resin are dispersed in a binder made of a thermoplastic resin, and this is applied to the surface of the base sheet to form a thermally expandable coating layer. The thermally expandable coating layer is then coated with a resin film containing polyvinyl alcohol as a main component.

In order to improve water resistance, polyvinyl alcohol having a degree of polymerization in the range of 500 to 1000 and a degree of saponification of 99 mol% or more is used.

More preferably, it is desirable to further improve the water resistance by adding a water resistant agent into the polyvinyl alcohol resin film.

[For production]

The thermally expandable coating layer is covered with a resin film mainly composed of polyvinyl alcohol that has good adhesion to molten toner, so even if the toner image area is raised by light irradiation, the toner image surface remains smooth. The colorant layer of the hot stamp foil can be transferred uniformly, and the colorant layer does not adhere to areas other than the toner image area. When polyvinyl alcohol having a polymerization degree of 500 to 1000 and a saponification degree of 99 mol% or more is used, water resistance can be improved.

Furthermore, within the polyvinyl alcohol resin film,
A three-dimensional image sheet with excellent water resistance can also be obtained by adding a water resistance agent.

Furthermore, by using polyvinyl alcohol as the material for the film, a film layer with a required thickness can be formed in a single coating process.

〔Example〕

Examples of the present invention will be described below.

FIG. 2(a) is a sectional view illustrating the configuration of the stereoscopic image C) and shows the thickness of each layer on an enlarged scale. In the figure,
Reference numeral 11 denotes a base material sheet, which has sufficient rigidity and heat insulation to prevent the thermally expandable microspheres, which will be described later, from expanding toward the back side of the base material sheet when heated and expanded, and has a temperature at which the microspheres expand. It is made of a material that does not soften, such as paper, synthetic paper, synthetic resin sheet, plywood, metal foil, etc.

12 is a thermally expandable coating layer in which propane, butane and other low-boiling vaporizable substances are microencapsulated with a thermoplastic resin such as vinylidene chloride-acrylonitrile, methacrylic acid ester-acrylic acid copolymer, vinylidene chloride-acrylic acid ester copolymer, etc. Thermally expandable microspheres 13 having a particle size of 10 to 30μ are made of, for example, a vinyl acetate polymer,
Acrylic polymer methacrylic acid polymer, styrene
It is formed by coating and drying on the base sheet 11 together with a binder made of a thermoplastic resin such as a butadiene polymer.

Note that as the heat-expandable microspheres, it is also possible to use a granular heat-sensitive organic foaming agent such as azobisisobutyronitrile.

14 is a film layer that prevents heat generation in the image area due to light irradiation,
It is heat resistant enough to withstand the heat during hot stamp foil processing and can fix toner images well, and is made of materials that do not easily adhere to hot stamp foil adhesives, such as polyester film and specially processed paper. You can, but
Experiments have shown that a film layer made of a resin containing polyvinyl alcohol as a main component provides particularly good results.

In order to form a film layer 14 of a resin containing polyvinyl alcohol as a main component on the thermally expandable coating layer 12, a polyvinyl alcohol aqueous solution is applied on the thermally expandable coating layer 12,
By drying, 1Ottm to 10.0μm
It is possible to form a film layer with a thickness of . The preferred thickness is 3 to 5 μm.

Polyvinyl alcohol is PVA- manufactured by Kuraray Co., Ltd.
105 (degree of polymerization 500), PVA-110 (degree of polymerization 70
0-1000) completely saponified type (saponification degree of 99 mol% or more) is suitable, and low molecular weight PVA-105
can be used to form a coating liquid with high concentration and low viscosity, and a sufficiently thick film layer can be formed even with one coating step. In addition, completely saponified polyvinyl alcohol with a saponification degree of 99 mol% or more is soluble in hot water, but
Since it is insoluble in cold water, the formed film layer exhibits good water resistance.

More preferably, an appropriate waterproofing agent is added to the polyvinyl alcohol resin film.

As such a water resistant agent, for example, epoxy resin is suitable, and Ehinonox P manufactured by Daik Perkyless Co., Ltd.
-9007-V etc. Other than this, urea
Formalin resin, melamine-formalin resin, polyamide urea-formalin resin, glyoxal, cyclic urea
Glyoxal reactants, formalin, glycerin glycidyl ether, polyamide-epoxy resins, ammonium zirconium carbonate, zinc sulfate, and the like can also be used.

The amount of such a waterproofing agent added is generally 1 to 20 parts by weight, preferably 5 to 10 parts by weight, per 100 parts by weight of the polyvinyl alcohol.

Formation and coloring of a three-dimensional image are performed as follows. Here, an example of coloring a three-dimensional image using hot stamp foil will be described with reference to FIG. 2.

Use a normal electrophotographic copying machine, etc., and use black toner (
or dark toner) to transfer the original image to a 3D image sheet (
Hereinafter simply referred to as a sheet. 5) Copy onto the film 14 on the thermally expandable coating layer 12 of Q. FIG. 2(b) shows toner image 1.
5 shows a cross section of a sheet Q on which No. 5 is formed.

Next, this sheet is irradiated with light.

An example of a light irradiation device is shown in FIG. Above the housing 2o, a light source lamp 21 such as a halogen lamp is provided below a reflecting mirror 22. Below the light source lamp 21, a conveyor belt made of metal or other heat-resistant material is connected to a driving pulley. It is suspended between a portion of the driven pulley and is configured to move in the direction of the arrow by a drive source (not shown). Also, 26
2 is a paper feed tray, and 27 is a paper discharge tray.

The power is turned on to start driving the conveyor belt 23, the light source lamp 21 is turned on, and the sheet Q is fed with the thermally expandable coating layer 12 on which the toner image 15 is formed facing the light source lamp 21K. send The sheet Q is irradiated with light by the light source lamp 21, but at this time, the image 15 formed with black toner absorbs the light energy and is heated, and the image 15
The thermally expandable coating layer 12 below is heated. As a result, the microspheres 13 in this portion rapidly expand, causing the thermally expandable coating layer 12 to bulge.

FIG. 2(c) shows a cross section of the sheet Q after the light irradiation process has been completed.

Next, the raised three-dimensional image surface is colored in a desired color, and for this purpose, the three-dimensional image surface made of black toner is coated with hot stamp foil.

The hot stamp foil S is, for example, a foil having a layered structure as shown in FIG. In the figure, 31 is a base film made of polyester film with a thickness of 5 to 30 μm, 32 is a release layer made of wax-based resin with a thickness of about 0.02 μm,
33 is a coloring material layer with a thickness of about 2μ, which contains resin, solvent, dye,
It is formed from a coloring material mixed with pigments etc. to form the desired color. 34 is a colored layer 3 made of high-purity aluminum using a vacuum evaporation method.
An aluminum thin film layer 35 having a thickness of about 0.04 μm is formed on 3, and 35 is an adhesive layer having a thickness of about 2 μm, which is made of a heat-sensitive and pressure-sensitive adhesive that exhibits good adhesion to melted toner. Note that the aluminum thin film layer 34 is formed only when forming a metallic color foil, and is not required for other color bases.

The coating treatment with the hot stamp foil S is performed as follows. First, the surface of the adhesive layer 35 of the hot-stamped foil S of a desired color is placed on the surface of the sheet Q on which the toner image 15 is provided, and the foil is heated and pressed between known heat rollers. As a result, the adhesive layer 35 of the hot stamp foil S firmly adheres to the molten toner forming the toner image 15 (see FIG. 2(d)). At this time, the adhesive layer 35 does not adhere to the film 14 on the sheet 11. When the base film 31 of the hot stamp foil S is peeled off from the sheet Q, the coloring material layers 33 and 34 of the hot stamp foil S remain adhered only on the toner image 15 (see FIG. 2(e)).

〔Effect of the invention〕

As explained above, the three-dimensional image sheet of the present invention is
Since the thermally expandable coating layer is further coated with a resin film mainly composed of polyvinyl alcohol to which molten toner adheres well, the thermally expandable coating layer in the toner image area is raised by light irradiation treatment. However, the surface of the toner image remains smooth, and the colorant layer of the hot stamp foil can be uniformly transferred. Furthermore, since the coloring material of the hot stamp foil does not adhere to the film surface on which the toner image is not formed, the sheet surface is not stained.

In addition, since we used polyvinyl alcohol, which has low viscosity even at high concentrations, as the material for the film that coats the thermally expandable coating layer, it is possible to form a film of the required thickness in the second coating process, making it easier to use. The process can be simplified. Furthermore, by using polyvinyl alcohol with a high degree of saponification, a three-dimensional image sheet with good water resistance can be obtained.

-Also, by adding an appropriate water resistance agent, it is possible to further improve the water resistance.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the structure of a conventional thermally expandable sheet and a three-dimensional image forming process, Fig. 2 is an explanatory diagram of the structure of a three-dimensional image sheet and a three-dimensional image forming process according to the present invention, and Fig. 3 is a light irradiation device. FIG. 4 is a cross-sectional view showing the main structure of the hot stamp foil. 1: base sheet, 12: thermally expandable coating layer, 13: thermally expandable microspheres, 14: polyvinyl alcohol resin film,
15: toner image, 33.34: coloring material layer, 35: adhesive layer, Q: sheet for stereoscopic image, S: hot stamp foil. Patent applicant Minolta Camera Co., Ltd. (a) (b) (c) Figure (a) (b) (C) Figure

Claims (2)

[Claims] (1) On a base sheet, thermally expandable microspheres obtained by micro-encapsulating a low-boiling volatile substance with a thermoplastic resin are dispersed in a binder made of a thermoplastic resin, and then applied to the base sheet surface. 1. A three-dimensional image sheet, characterized in that the sheet is coated to form a thermally expandable coating layer, and the thermally expandable coating layer is covered with a resin film containing polyvinyl alcohol as a main component. (2) In the three-dimensional image sheet according to claim 1,
A sheet for stereoscopic images, characterized in that the polyvinyl alcohol has a degree of polymerization in the range of 500 to 1000 and a degree of saponification of 99 mol% or more.