JPH0257767B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a sheet having an uneven pattern that is completely in sync with a printed pattern on the surface. Conventionally, resin decorative sheets with wood grain or geometric uneven patterns on the surface have been widely used as exterior panels for furniture, fittings, or electrical equipment, but these sheets are often decorated with embossing. Manufactured. However, with such mechanical methods, it is difficult to create an uneven pattern that closely matches the pattern of the sheet, and there is also the problem that it requires a large number of large equipment, which increases manufacturing costs. be. The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a simple method for manufacturing a resin sheet having a concavo-convex pattern that is completely in sync with a printed pattern. The method for manufacturing a resin sheet according to the present invention includes printing a pattern in a desired shape on the surface of a thermoplastic resin sheet using ultraviolet curable resin ink, irradiating it with ultraviolet rays, and then heating and stretching the resin sheet to print the pattern on the surface of the resin sheet. It is characterized by forming a concavo-convex pattern that is synchronized with the . The present invention will be described below based on drawings showing examples. FIG. 1 shows a base resin sheet 1 before being heated and stretched. The base sheet is not particularly limited, but for example, polyvinyl chloride resin, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl acetate, saturated polyester, polyvinylidene chloride, acrylic resin, thermoplastic polyurethane resin, etc. can be used. It will be done. The base sheet may contain various necessary additives depending on the resin, such as plasticizers, fillers, colorants, antioxidants, and the like. The thickness of such a base sheet is such that when the base sheet is heated and stretched, the non-printing part of the sheet is stretched and the printed part is effectively raised to form the desired uneven pattern. Generally, the thickness is preferably about 0.05 to 1 mm. According to the method of the present invention, a desired pattern is printed on the surface of such a base resin sheet using ultraviolet curable resin ink 2. The thickness of the printed pattern is selected so that when the printing ink is crosslinked and then heated and stretched, the printed pattern portion of the sheet is not substantially stretched. The ultraviolet curable resin ink used in the method of the present invention usually contains a film-forming component, a reactive diluent, and a photopolymerization initiator, and if necessary, a solvent,
It is an ink made of a resin composition that contains dyes, pigments, fillers, etc., and is usually crosslinked and cured within a few seconds when exposed to ultraviolet rays. High molecular weight polymers, oligomers, monomers, etc. having an acryloyl group, a methacryloyl group, or other addition-polymerizable double bonds in the molecule are usually used as the film-forming component. In the present invention, polyester (meth)acrylate, urethane (meth)acrylate, epoxy (methacrylate, etc.) are preferably used as the film-forming component.The reactive diluent reduces the viscosity of the film-forming component. It is blended to make the coating film-forming component cross-linked and networked by UV irradiation, and is usually a polyfunctional oligomer or monomer. As the reactive diluent, monomers having two or more acrylate groups and/or methacrylate groups in the molecule are preferably used, and specific examples thereof include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth) ) acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, and the like. -ethylhexyl (meth)
Acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate N
Monofunctional monomers such as -vinyl-2-pyrrolidone and tetrahydrofurfuryl (meth)acrylate can be used in combination. Further, as the photopolymerization initiator, benzyl, benzophenone, benzoin ether, chlorothioxanthone, diethoxyacetophenone, benzyl dimethyl ketal, etc. are usually used. The blending amount of each component in the above-mentioned ultraviolet curable resin ink is usually about 20% of the film-forming component.
-90% by weight, preferably 40-70% by weight, reactive diluent about 10-80% by weight, preferably 30-60% by weight, photoinitiator about 0.5-10% by weight, optionally The above-mentioned components are further blended. Next, according to the present invention, ultraviolet rays are irradiated from the printed pattern surface of the sheet to crosslink and cure the printed pattern. The method for crosslinking and curing the ink may be any conventionally known method, for example,
UV light sources such as xenon lamps, low pressure, medium pressure, high pressure or extra high pressure mercury lamps may be used. The amount of ultraviolet rays that is sufficient to fully cure the ultraviolet curable resin ink can be selected depending on the ink.
In the case of an 80W/cm mercury lamp, irradiation can be performed for one to several seconds. When the sheet is then heated and stretched, only the portion of the base sheet that does not have a printed pattern on its surface is substantially stretched, as shown in FIG.
The sheet portion having the printed pattern on its surface is not substantially stretched because the ink has been cross-linked and cured, and thus the sheet portion having the printed pattern rises from the sheet surface, creating an uneven pattern that perfectly matches the printed pattern. form. The heating temperature of the above sheet is usually
A suitable temperature range is 100 to 200°C, and a suitable stretching ratio is 5 to 40% in both length and width. Note that it is desirable that the film be stretched at approximately the same stretching rate in both length and width. By controlling the heating temperature and stretching rate, it is possible to control the stretching of the sheet portion that does not have a printed pattern on its surface, and to control the height of the protrusion of the sheet portion that has a printed pattern. FIG. 3 shows, in another embodiment of the method of the invention,
The laminated base sheets are shown before heating. That is, after irradiating the surface of a base sheet 1 with a printed pattern using ultraviolet curable resin ink 2 with ultraviolet rays in the same manner as described above, another resin sheet, for example, a vinyl chloride resin sheet 3, is laminated on the back surface of the base sheet 1. By adhering and laminating the sheets by the method of Shion et al., and then heating and stretching the sheets, the resin sheet 3 follows the stretching of the base sheet 1 in the non-printed pattern area, as shown in FIG. and is stretched, thus forming an uneven pattern in perfect synchronization with the printed pattern. When a colored sheet is used as the resin sheet 3, this sheet can be used as a background of a printed pattern. As described above, according to the method of the present invention, a desired pattern is printed on a stretchable base sheet using ultraviolet curable resin ink, and the printed pattern surface is crosslinked and cured by irradiating ultraviolet rays. Since the base sheet is heated and stretched, only the portion of the sheet that does not have a cross-linked ink pattern on its surface is substantially stretched, while the portion that has a printed pattern on its surface is not substantially stretched. The areas are raised on the surface of the sheet, forming an uneven pattern that perfectly matches the printed pattern. The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 A resin composition containing 100 parts by weight of vinyl chloride resin with an average degree of polymerization of 1100, 12 parts by weight of a conventional plasticizer, and appropriate amounts of stabilizers and pigments was molded into a sheet with a thickness of 0.075 mm by a calendar method. . After printing a wood grain pattern on the surface of this base sheet using ultraviolet curable resin inks A to C having the compositions shown in the table, and irradiating it with ultraviolet rays for 1 second using a mercury lamp with a dominant wavelength of 356 mμ and an output of 80 W/cm, ,170℃
Stretched at a temperature of 15% in both length and width.

【table】

[Table] No matter which ink was used, it was possible to obtain a sheet in which a convex pattern was formed in synchronization with the printed pattern portion. Example 2 The printed sheet obtained in Example 1 was similarly irradiated with ultraviolet rays. Separately, a resin composition containing 100 parts by weight of vinyl chloride resin with an average degree of polymerization of 1100, 17 parts by weight of a normal plasticizer, and appropriate amounts of stabilizers, pigments, and fillers was prepared by calendering into a sheet with a thickness of 0.1 mm. This was then laminated on the back side of the base sheet. Next, this laminated sheet
Stretched at a temperature of 170°C with a stretching ratio of 15% in both the length and width,
No matter which ink was used, it was possible to obtain a sheet in which a convex pattern was formed in synchronization with the printed pattern portion.

[Brief explanation of the drawing]

The drawing shows an embodiment of the method according to the invention, in which the first
The figure is a cross-sectional view of a main part of a base sheet having a pattern printed with ultraviolet curable resin ink on its surface, FIG. FIG. 3 is a sectional view of a base sheet laminated with, for example, colored resin sheets, and FIG. 4 is a sectional view of a sheet having an uneven pattern according to the present invention obtained from the sheet of FIG. 3. 1... Base material sheet, 2... Ultraviolet curable resin ink, 3... Resin sheet.

Claims (1)

[Claims] 1. Printing a pattern in a desired shape on the surface of a thermoplastic resin sheet using ultraviolet curable resin ink, irradiating it with ultraviolet rays, and then heating and stretching to form an uneven pattern on the surface of the resin sheet that matches the printed pattern. A method for producing a resin sheet characterized by: