JPS6362383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a convex pattern on the surface of a sheet.

BACKGROUND ART Conventionally, synthetic resin sheets having a woodgrain pattern or a geometric uneven pattern have been attached to the surfaces of furniture, fittings, or interior wall boards to improve their appearance and appearance.

By the way, as a method for manufacturing the above-mentioned uneven patterned sheet, mechanical means using an embossing roll or a colored print roll, or, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 54764, chemical means are used to create a desired uneven pattern by foaming using a reactive plasticizer that can be polymerized and cured by ultraviolet rays and a foaming agent, but in the case of the former. However, in the latter case, only foam can be produced and it is difficult to produce products with excellent strength.Furthermore, in the former method, printing is required. Since the process of applying the pattern layer and the unevenness are separate processes, it is difficult to perfectly match the uneven pattern and the printed pattern.Moreover, since the printed pattern layer is applied directly to the outer surface, it is difficult to completely match the pattern layer with the printed pattern. The disadvantage was that the printed pattern disappeared or the pattern became unclear due to wear.

In view of the above drawbacks, the present invention aims to provide a method for forming a convex pattern on the surface of a sheet by chemical means that does not require large-scale equipment, and in which the printed pattern and the convex pattern completely match. As a result of intensive research conducted by the inventors, it was found that by masking the surface of a synthetic resin sheet that can be cross-linked with ultraviolet light with a substance that does not transmit ultraviolet light, and then irradiating it with ultraviolet light, it is possible to create a sheet that does not contain any foaming agents. The inventors discovered that when this material is heated, the ultraviolet crosslinked portion and the non-ultraviolet crosslinked portion are clearly separated, and each undergoes unique expansion and deformation, leading to the present invention.

That is, the gist of the first aspect of the present invention is that on the surface of a synthetic resin sheet that can be crosslinked by ultraviolet rays,
A desired pattern is printed using an ink that does not transmit ultraviolet rays and contains a polymerization inhibitor if necessary, and then ultraviolet rays are irradiated from the surface.
This is a method for forming a convex pattern on the surface of a sheet, which is characterized by heating the sheet surface in a non-stretched state. Then, a desired pattern is printed using ink containing a polymerization inhibitor, etc. as necessary, and then a synthetic resin sheet or film that transmits ultraviolet rays is laminated and polymerized on the surface, and then ultraviolet rays are irradiated from the surface, and then the sheet is unstretched. This is a method for forming a convex pattern on the surface of a sheet, which is characterized by heating the sheet surface.

In the first and second inventions, the composition of the synthetic resin sheet capable of crosslinking with ultraviolet light includes a vinyl chloride resin, a photoreactive plasticizer, a general plasticizer, a photosensitizer,
It consists of a thermal polymerization inhibitor, a stabilizer, a pigment, and other compounds added as necessary.

Examples of vinyl chloride resin include vinyl chloride homopolymer or vinyl chloride and vinyl acetate, acrylonitrile, styrene, (meth)acrylic acid ester,
A copolymer of one or more of ethylene, propylene, butylene, etc. may be used alone or as a mixture, and a mixture of other polymers compatible with the vinyl chloride resin may also be used.

As the photoreactive plasticizer, an oligomer or monomer that acts as a plasticizer before irradiation with ultraviolet rays and is crosslinked by irradiation with ultraviolet rays is used, and as the oligomer, oligoester acrylate or the like is used. In addition, monomers include polyhydric alcohols and acrylic esters, polyhydric alcohols and methacrylic esters, etc. As polyhydric alcohols and acrylic esters, 1.6
Hexanediol diacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dipentaerythritol pentaacrylate, etc. are used, and as polyhydric alcohol and methacrylic acid ester, 1.6
Hexanediol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, dipentaerythritol pentamethacrylate, etc. are used. These UV-crosslinkable photoreactive plasticizers may be used alone or in combination.

General plasticizers include phthalate ester plasticizers such as di2-ethylhexyfluphthalate, di-normal octyl phthalate, dihexyl phthalate, and diisodecyl phthalate, phosphate ester plasticizers, polyester plasticizers, and trimethate ester plasticizers. Alternatively, epoxidized soybean oil or the like may be used.

As photosensitizers, photoreactive plasticizers are used for the purpose of promoting reactions caused by ultraviolet rays, and benzoin alkyl ethers such as benzoin methyl ether and benzoin isopropyl ether, benzyl, benzophenone, and other commonly used photosensitizers are used. used.

Thermal polymerization inhibitors are used to prevent photoreactive plasticizers from crosslinking due to heat during sheet molding, and commonly used examples include picric acid, phenol, hydroquinone, hydroquinone monomethyl ether, benzoquinone, phenothiazine, and methylhydroquinone. A thermal polymerization inhibitor is used.

As stabilizers, commonly used metal soaps, tin compounds, phosphite esters, epoxy compounds, antioxidants, etc. are used as necessary.

As the pigment, any commonly used pigment for vinyl chloride resin may be used.

In addition, the amount of the synthetic resin sheet that can be crosslinked by ultraviolet rays is as follows:
5 to 60 parts by weight of photoreactive plasticizer per 100 parts by weight;
0 to 120 parts by weight of a general plasticizer, 0.01 to 5% by weight of a photosensitizer based on the photoreactive plasticizer, a thermal polymerization inhibitor and a stabilizer, and pigments if necessary. Ru.

In addition, as inks that do not transmit ultraviolet rays, pigments that do not transmit ultraviolet rays such as carbon black, titanium white, red iron, and yellow lead, or calcium carbonate,
Inks containing fillers such as clay, extender pigments, or benzophenone-based, benzotriazole-based, or salicylate-based ultraviolet absorbers are used.
Incidentally, these may be used with addition of a polymerization inhibitor, if necessary.

As shown in FIG. 1, a wood-grain pattern, for example, is applied to the surface 1A of the ultraviolet crosslinkable synthetic resin sheet (hereinafter referred to as the sheet) 1 molded with the above formulation using an ink 2 that does not transmit ultraviolet rays. print and then sheet 1 as shown in FIG.
UV rays 3 are irradiated from the surface.

At this time, the portion 1B irradiated with the ultraviolet rays 3 is crosslinked, and the portion to which the ink 2 is attached (hatched portion) remains without being crosslinked.

Next, as shown in FIG. 3, if the sheet 1 is heated in an unstretched state, the portions that were not irradiated with ultraviolet rays (hatched portions) have a lower viscosity during heating than the irradiated portions. The sheet reaches a molten state, is pushed by the expansion of the irradiated area, bulges out due to viscous deformation, and is cooled while maintaining that shape, resulting in a sheet with patterned areas having convex portions.

Therefore, according to this method, only the portion printed with ink 2 stands out as a convex pattern, so that the printed pattern and the convex pattern can be perfectly matched.

Incidentally, in order to prevent a polymerization reaction from occurring in the printed portion during ultraviolet irradiation, a polymerization inhibitor may be added to the ink to further prevent the polymerization reaction from occurring.

Further, in the case of using the above method, the printed portion 2 is exposed to the outside, so there is a risk that the pattern may disappear due to wear or the like.

For this reason, a synthetic resin film or sheet that transmits ultraviolet rays is further laminated and polymerized on the surface of the sheet 1.

That is, as shown in FIG.
After printing a pattern on A with ink 2 that does not transmit ultraviolet rays, as shown in FIG. 4, a film or sheet 4 that transmits ultraviolet rays is laminated and polymerized on the surface of sheet 1, as shown in FIG. 5. irradiate with ultraviolet rays 3.

As shown in Fig. 6, if the unstretched state is heated, the part irradiated with the ultraviolet rays 3 will thermally expand, causing the part not irradiated with the ultraviolet rays 3 to bulge out. Only the patterned portions on the film or sheet 4 are surely matched to form a convex pattern.

As shown in FIG. 1, the sheet 1 shown in FIG. 1 has a printed layer 5 in the color that should be the background color of the sheet 1, or a film or sheet (not shown) on the back side that does not interfere with ultraviolet irradiation, as shown in FIG. (2) may be laminated, and by doing so, the ground color, pattern, and convex pattern of the sheet 1 can be integrated, and a sheet with extremely good aesthetic appearance can be manufactured.

Furthermore, as the film or sheet 4 that transmits ultraviolet rays shown in FIG. 4, a transparent one made of ordinary synthetic resin may be used, or a sheet or film having the same composition as the ultraviolet crosslinkable sheet 1 may be used. In this configuration, the film or sheet 4 on the surface of the sheet is also cross-linked with ultraviolet rays, so that strong heat resistance can be imparted to the entire sheet 1, which is convenient.

Further, as shown in FIG. 3 or FIG. 6, in the step of heating the sheet 1 to bring out the convex pattern, the sheet 1 is wound around the heating drum D in a non-stretched state as shown in FIG. For example, by concentrating the embossment direction of the convex pattern on the surface side, a clear convex pattern can be obtained.

In this case, as shown in FIG. 9, it is also possible to wrap the sheet 1 irradiated with ultraviolet rays so that the surface 1A is in contact with the drum surface D, and then heat it to make the convex pattern bulge out to the back side. be.

Also, if a polymerization inhibitor is added to the printing ink,
As the polymerization inhibitor penetrates into the synthetic resin layer,
The effect of preventing ultraviolet crosslinking in the printed area is enhanced, but in this case, it is also possible to prevent the crosslinking reaction only by the polymerization inhibitor added to the ink, and in this case, printing on the back side of the sheet 1 The same effect can be obtained by applying ultraviolet rays from the surface side.

Next, embodiments of the invention will be described.

Example 1 Vinyl chloride resin 100 parts by weight Reactive plasticizer (trimethylolpropane triacrylate) 20 General plasticizer (DOP) 20 Photosensitizer (benzoin methyl ether)
2% by weight based on reactive plasticizer Thermal polymerization inhibitor (hydroquinone) 2% by weight Stabilizer Required amount Thickness that can be cross-linked by UV rays with the above compounding composition 0.1
mm sheets are molded using the calendar method, and woodgrain patterns are applied to the surface using carbon black, red iron, or
Printed with ink toned with yellow lead, titanium white, etc., and then printed on this surface with a main wavelength of 365 mμ, 120 W /
UV irradiation was performed at a speed of cm 5 m/min, and then
Wrap it around a drum with a radius of 1m and leave it unstretched.
When heated to 190°C, a clearly distinguishable convex pattern appeared on the printed area. Thereafter, the sheet was cooled to 50° C. on a drum and taken off, but the pattern did not disappear and a sheet with a clear convex pattern was obtained.

Example 2 On the back side of an ultraviolet crosslinkable sheet having the same composition as that shown in Example 1, the following compounding composition was added:
After laminating and polymerizing sheets formed to a thickness of 0.2 mm by the calender method, a pattern was printed on the surface of the ultraviolet crosslinkable sheet using the same ink as in Example 1, and the sheets were irradiated with ultraviolet rays and treated in the same manner as in Example 1. When heating was performed under stretching, a clearly distinguishable convex pattern appeared in the printed area. Thereafter, when the sheet was removed from the drum under a high temperature condition with a stretching tension of 5% or less, the pattern did not disappear, and a sheet with a clear convex pattern was obtained.

Table: Vinyl chloride resin (-1100) 100 parts by weight General plasticizer (DOP) 30〃 Stabilizer Required amount Pigment 〃 Filler 〃 Example 3 A UV crosslinkable sheet with the same composition as that shown in Example 1 was prepared. After a printed pattern was applied to the surface, a vinyl chloride film having the composition shown in Example 2 was laminated and polymerized, irradiated with ultraviolet rays by the same means as in Example 1, and heated in an unstretched state. Example 1 on the surface of vinyl chloride film
A convex pattern almost similar to that of the PVC surface is observed, and due to the synergistic effect of the printed pattern observed through the vinyl chloride surface and the light reflectance of the exposed convex pattern, it has an extremely excellent convex pattern. A sheet having an appearance was obtained.

Example 4 In place of the vinyl chloride resin in Example 3, a film with the same composition as in Example 1 that can be crosslinked by ultraviolet rays was used, and UV irradiation and heating were carried out in the same manner as in Example 3. After the pattern was exposed, ultraviolet rays were irradiated.

This one has a convex pattern, and
The heat resistance of the surface was also excellent.

As described above, this invention utilizes an ultraviolet cross-linking reaction to express the convex pattern, so it is possible to create a convex pattern that perfectly matches the printed pattern, and also to make the convex pattern appear. However, since this process takes advantage of the difference in physical properties between the thermal expansion of the cured part and the flexibility of the uncured part, there is no decrease in the strength of the sheet due to the appearance of convex patterns, thus producing products with excellent strength. Furthermore, the heat resistance of the sheet is improved by the ultraviolet crosslinking reaction, and beautiful sheets with excellent heat resistance strength can be easily produced.

[Brief explanation of drawings]

FIGS. 1 to 6 are explanatory diagrams showing the steps of this invention, and FIGS. 7 to 9 are explanatory diagrams of other embodiments. 1... Sheet capable of crosslinking with ultraviolet rays, 1A... Surface, 2... Ink that does not transmit ultraviolet rays, 3...
Ultraviolet light.

Claims (1)

[Claims] 1. On the surface of an ultraviolet crosslinkable synthetic resin sheet,
A desired pattern is printed using an ink that does not transmit ultraviolet rays and contains a polymerization inhibitor if necessary, and then ultraviolet rays are irradiated from the surface.
A method for forming a convex pattern on the surface of a sheet, which is characterized by heating the sheet surface in a non-stretched state. 2. On the surface of a synthetic resin sheet that can be crosslinked with ultraviolet light,
A desired pattern is printed using an ink that does not transmit ultraviolet rays and is added with a polymerization inhibitor if necessary, then a synthetic resin sheet or film that transmits ultraviolet rays is laminated and polymerized on the surface, and then ultraviolet rays are irradiated from the surface. A method for forming a convex pattern on the surface of a sheet, the method comprising: heating the sheet surface in a non-stretched state. 3. The method for forming a convex pattern on the surface of a sheet according to claim 1 or 2, wherein the synthetic resin sheet capable of crosslinking with ultraviolet rays is a sheet whose back surface is colored and printed in a desired color. 4. The method for forming a convex pattern on the surface of a sheet according to claim 1 or 2, wherein the synthetic resin sheet capable of crosslinking with ultraviolet rays is a laminated sheet of a synthetic resin film or sheet with a colored back side. 5. The method for forming a convex pattern on the surface of a sheet according to claim 2, wherein the synthetic resin sheet or film that transmits ultraviolet rays is a synthetic resin sheet or film that can be crosslinked with ultraviolet rays.