JPS6261433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel thermosetting resin decorative board, and its object is to produce an embossed decorative board in which the printed pattern and the surface irregularities are completely synchronized or harmonized. The object of the present invention is to provide a method for efficiently producing embossed materials without using a special embossing plate.

Conventionally, various methods have been proposed for forming irregularities on the surfaces of melamine resin decorative boards, diallyl phthalate resin decorative boards, benzoguanamine resin decorative boards, and the like.
Here are some examples: (1) A method in which a metal plate whose surface has been roughened by an etching method or the like is directly molded as a backing plate.

(2) A method in which a metal plate whose surface has been roughened by etching, etc. is used as a matrix, a resin plate made from this is used as a backing plate, and molding is performed via a release film.

(3) A method in which a material with irregularities such as paper or cloth is used as a mold and molded using a release film, aluminum foil, etc.

(4) A method in which a release sheet is embossed in advance, and then the recesses on the back side are filled with resin and then molded into a mold.

(5) A method of molding a release sheet with raised printing applied to the back side as a mold.

(6) A method of creating recesses in the ink area by using special printing ink and changing the curing speed of the resin in the ink area.

Among these methods, methods (1) to (5) make it extremely difficult to completely match the printed pattern and the uneven shape. This is because the printing pattern element and the unevenness forming element are separated, and even if these two are adjusted to be similar and synchronous, in reality, the resin impregnation and drying process of decorative paper Due to irregular expansion and contraction, it was virtually impossible to match them perfectly. In addition, method (6) can be applied to some extent for decorative laminates that are molded under relatively low pressure, such as dap resin decorative laminates and polyester resin decorative laminates, but it cannot be applied to decorative laminates such as high-pressure melamine decorative laminates. It could not be applied to decorative laminates that are molded under high pressure. Another method has been proposed in which the convex portions of the cover plate, which has an uneven surface, are colored in advance, and the coloring agent is transferred to the concave portions of the decorative plate at the same time as pressing and molding. According to this method, since the colorant was present on the surface of the decorative board, there were problems with durability such as abrasion resistance.
This drawback is also observed in method (6). The present invention eliminates all of these drawbacks and provides a method for easily producing a decorative board in which the printed pattern and surface irregularities perfectly match, and which has no difference in durability from conventional decorative boards. be.

Next, the method of the present invention will be explained in detail based on the drawings.

First, as shown in FIG. 1, a transparent sheet 1 that will form a surface protective layer of a decorative board as a final product is prepared.
The transparent sheet is a paper that becomes substantially transparent after being formed into a decorative board, and is preferably one with good resin impregnation properties, such as overlay paper for decorative boards, synthetic resin pulp paper, linter paper, tissue paper, transparent paper, etc. Can be used. The transparent sheet may be translucent or colored and transparent depending on the desired design effect.

Next, a release layer 2 is formed on the surface of the transparent sheet (the surface that will form the surface of the decorative board). As a method for forming the mold release layer, when the mold release layer is a sheet-like material, bonding with an adhesive layer 3 is common, and when the material of the mold release layer is a thermoplastic resin, melting It is also possible to integrate the thermoplastic resin directly onto the surface of the transparent sheet. To be more specific about the release layer, sheet-like materials for the release layer include polypropylene film, polyester film, aluminum foil, sheets of these backed with paper, release paper, etc. A sheet-like material that has mold releasability for the thermosetting resin can be used. As a method of integrating these release sheets and transparent sheets, there is a method of using a thermosetting resin used for the intended decorative board as an adhesive layer. That is, in the case of a melamine decorative board, for example, the purpose is achieved by applying a solution of modified melamine resin to either side of a release sheet or a transparent sheet, then bonding the two together and drying. In this case, there is no need for particularly strong adhesion in integrating the two, as long as there is no peeling or other problem in the next printing process, and temporary adhesion is sufficient. In this case, the thermosetting resin used as the adhesive layer hardens during the decorative laminate molding process and becomes the surface layer of the decorative laminate, so the type and composition of this resin must be determined in advance to ensure its function as the decorative laminate surface layer. It is desirable to satisfy the following. If adhesives such as those normally used for paper processing are used as the adhesive layer, these adhesive layers remain on the surface of the decorative laminate after molding, resulting in insufficient surface performance of the decorative laminate. I can't wait.

Next, another method for forming the release layer will be described.

As shown in Fig. 2, when the material of the release layer is a thermoplastic resin such as polypropylene resin or polyester resin, these resins are extruded in a molten state onto the surface of the transparent sheet 4, cooled and solidified to be integrated. It is possible to do this. This method has the advantage that the transparent sheet 4 and the release layer 5 can be integrated without using a special adhesive layer, but on the other hand, the surface condition of the final product, the decorative board, surface condition of
That is, in this case, there is a problem in that it is determined by the surface condition of the transparent sheet. This is a property that can be both an advantage and a disadvantage depending on the case. For example, if the surface condition of the transparent sheet is uneven, it will remain on the surface of the final product, the decorative board. This is undesirable because it appears uneven, but if the surface condition of the transparent sheet is well adjusted, a decorative board with a unique texture can be obtained, so it can be an advantage. .

Next, the printing process will be described. Through the steps described above, a composite sheet in which a transparent sheet and a release sheet are laminated and integrated is used as a printing material to perform printing.

As shown in FIG. 3, an arbitrary pattern 9 is printed on the surface of the transparent sheet 7, usually by gravure printing. The printing ink may be exactly the same as that normally used for printing decorative paper for decorative laminates. The printing order is the reverse of the normal surface printing. If necessary, a solid printing concealing layer may be provided at the end. Next, the original fabric is reversed and a raised print 10 is applied to the surface of the release sheet, which is the back side. There is no problem in reversing the original fabric when the original fabric is a single sheet.
If the original fabric is in the form of a web, this can be easily done by using a double-sided printing machine or by installing a reversing device before the final unit of a conventional rotogravure printing machine. In any case, in order to completely synchronize the raised print 10 with the pattern 9 on the web-like original fabric, it is necessary to print in one step with one printing machine. This is because it is practically impossible to accurately control the elongation of the original fabric due to tension during printing for each individual printing process. When the original fabric is sheet-fed or when the pattern and the raised printing do not need to be synchronized, it is possible to separate the printing processes. The printing method is not particularly limited to gravure printing, and offset printing, flexographic printing, screen printing, etc. can also be selected arbitrarily. However, for raised printing, gravure printing or screen printing (including rotary screen printing) is more advantageous in terms of ink film thickness. The ink used for raised printing must not be softened by heating during the molding of the decorative board, and the ink must be mainly composed of thermosetting resin.
It is desirable to use an ink with a high solids content to which extender pigments and solvents are added as necessary. In addition, the solid content ratio can be arbitrarily selected from a range with a higher solid content ratio than normal gravure ink to one with a solid content of 100%. In consideration of printability, materials whose main components are two-component urethane resin, epoxy resin, unsaturated polyester resin, etc. are common.

Next, after printing is performed on both sides of the composite sheet of the transparent sheet and the release sheet as described above, the transparent sheet is impregnated with a thermosetting resin. The impregnation is carried out by applying a solution 11 of a thermosetting resin monomer, oligomer, prepolymer, etc. from the transparent sheet side 13 of the composite sheet 12 and drying as shown in FIG. Although FIG. 4 is a schematic diagram showing gravure coating, any other coating method can be selected, such as kiss coating or reverse roll coating. However, this resin impregnation step does not necessarily have to be performed after the printing step, but may be performed before the printing step, or before or simultaneously with the integration of the release layer. Furthermore, in some cases, this impregnation can be omitted. The same finishing effect can be achieved by impregnating a concealing sheet placed under the transparent sheet during molding with resin in advance, and allowing the molten resin to soak into the transparent sheet during pressing. Alternatively, the transparent sheet may be impregnated with the resin of the adhesive layer used to bond the transparent sheet and the release sheet into the transparent sheet during molding. These methods are very advantageous because one impregnation step can be omitted. Furthermore, it is possible to avoid the problem of curling of the condensed sheet due to shrinkage of the transparent sheet during impregnation and drying.

However, from the viewpoint of the surface performance of the resulting decorative laminate, it is desirable that the transparent sheet be impregnated with a sufficient amount of resin. Therefore, the amount of resin impregnated, the impregnation time, etc. should be determined in accordance with the desired effect and process. Must be selected in the relationship.

Next, the molding process will be described. As shown in FIG. 5, a concealing sheet 15 is placed on the base material 14 as required. Titanium paper is usually used as the concealing sheet. It is desirable to impregnate the concealing sheet with a thermosetting resin and dry it in advance. Furthermore, if a concealing layer is formed by solid printing on the surface of the transparent sheet, the concealing sheet can be omitted.

Composite sheet 1 that has undergone printing, impregnation, etc.
6 is placed with the pattern printed surface facing the base material side, and a smooth mirror plate 17 is placed on top of this. If necessary, a lower mirror plate 18 is placed under the base material. The above set is passed through the cushions 19 and 20 to the heating plate 2.
1 and 22, and heat and press under normal pressing conditions.

In the heating and pressurizing process, as shown in Figure 6,
When the raised ink portion 23 is pressed against the smooth mirror plate 24, the release layer 25 is deformed and a convex portion 26 is formed on the transparent sheet side.
7 is pushed in to form a recess 28. Therefore, the raised printed portion on the back side of the composite sheet is expressed as a concave portion on the decorative board. Further, the transparent sheet 27 is integrated with the base material 29 and the concealing layer 30 to form a decorative board.

After the molding process is completed, as shown in FIG. 7, when the release layer 31 adhering to the surface is peeled off and removed, an embossed decoration having recesses 32 corresponding to the raised printed portions of the composite sheet is formed on the surface. A plate 33 is obtained.

The decorative board obtained in this way has a very high design effect because the printed pattern and the emboss are completely in sync, and it is also durable because a transparent protective layer is formed on the surface. It is also perfect in this respect. Furthermore, the method of the present invention is extremely advantageous in terms of production since it is not necessary to prepare expensive embossing plates, resin embossing plates, etc. for embossing.

Next, examples of the present invention will be shown.

Example 1 Overlay paper for decorative board (manufactured by Kojin Co., Ltd.)
A composite sheet was prepared by laminating the rough surface of OL2mils (25 g/m ² ) and the matte embossed surface of a 25 μ thick CPP film. The laminating method is melamine resin for melamine decorative board (NicaResin S manufactured by Nippon Carbide Co., Ltd.).
-260) as an adhesive, applied it to the CPP film, and then pressure-bonded the overlay paper in a semi-dry state. According to this method, it was possible to prevent the smooth surface of the overlay paper from becoming rough due to seepage of the melamine resin.

Next, using a printing machine equipped with a reversing device in front of the final unit of a four-color gravure rotary printing press, the oak wood grain pattern consisting of three plates is reversely printed on the overlay paper side (smooth side) of the composite sheet. The sheets were printed in sequence, and then the sheets were reversed and raised printing was performed on the CPP film surface of the composite sheet using a printing plate corresponding to the wood grain pattern conduit printing plate, which was dried and then rolled up. Since the composite sheet is translucent as a whole, it was possible to align the front and back surfaces by seeing through it without using any special equipment. For the raised printing, a two-component urethane resin (solid content: 60%) was used as ink. The drying conditions are
It became tack-free at 120℃ for 20 seconds, but
It took another week for the raised ink to completely harden. The specifications of the gravure plate used for raised printing were 100 screen lines/inch plate depth of 100μ. In addition, the direction of the pattern of the raised printing version was reversed from that of the third version of the picture version. (Originally, the raised printing plate is in the normal direction and the pattern plate is in the reverse direction, but in the case of a pattern such as a wood grain pattern that has no absolute right or wrong direction, the number of prints is large. It is more advantageous in the plate-making process to make the pattern plate as usual and make the raised printing plate with a small number of plates in the opposite direction.) Next, as described above, the printed composite sheet is cut to the specified size. It was cut into sheets for molding. Also,
Titanium paper (80 g/m ² ) used as a reference base color when printing a pattern was impregnated with an aqueous solution of the melamine resin for melamine decorative board and dried to prepare melamine resin-impregnated paper and use it as a concealing sheet. The amount of resin impregnated was 70 g/m ² , which was higher than usual. Next, the anti-warping impregnated sheet, phenol resin-impregnated core paper (4 sheets), concealing sheet, composite sheet (design printed facing downwards), and upper mirror plate are placed on top of the lower mirror plate in this order, and this set is placed through the cushion paper. The material was inserted between hot platens, and hot-cold press molding was performed at 145°C for 20 minutes at 80 kg/cm ² and cooled for 20 minutes. When the release layer adhering to the surface is removed, the part of the resulting decorative board that corresponds to the raised printing, that is, the conduit part, forms a concave part in perfect synchronization with the printing, resembling the surface of a natural wood veneer board. It has a beautiful finish. Furthermore, since the structure is completely the same as that of conventional melamine decorative boards, there was no difference in physical properties such as abrasion resistance.

Example 2 Overlay paper for decorative board (manufactured by Kojin Co., Ltd.)
A composite sheet was prepared by laminating the rough surface of OL4mils (42 g/m ² ) and the satin-embossed surface of a 25 μ thick CPP film. The lamination method uses melamine resin for melamine decorative boards (Cymel manufactured by Nippon Cyanamid Co., Ltd.).
We used a method in which overlay paper was impregnated with an aqueous solution of 412), and after drying, the CPP film was pressed while the adhesive remained. Since the smooth surface of the overlay paper of the obtained composite sheet was somewhat rough due to the resin impregnation, a flexo printing method was used to print the pattern in consideration of printability.

A modified tile pattern consisting of four colors is printed on the overlay paper in the reverse printing order, and after being reversed, CPP is printed using a rotary screen plate with the same diameter as the flexo plate.
A pattern corresponding to the tile joints was printed on the film surface in synchronization with the flexo pattern. The same two-component urethane resin used in Example 1 was used as the ink. Titanium paper (100 g/m ² ), which was used as a reference base color when determining the color, was impregnated with the melamine resin for decorative boards and dried to form a concealing layer. The sheets cut to predetermined dimensions were stacked in the same order as in Example 1, and hot-press molded. The molding conditions are 145
℃35 minutes 80Kg/ ^cm2 Cooling 20 minutes. The resulting decorative board had large concave areas at the joints of the tile pattern, giving it an extremely three-dimensional effect. Also,
The physical properties of this melamine decorative board were not inferior in any way compared to ordinary decorative boards.

Example 3 PP was applied to the rough surface of acrylic resin fiber paper (transparent paper).
25μ resin by extruder coating
A release layer was formed by coating, and a composite sheet was created. Using the gravure printing machine used in Example 1, an abstract pattern consisting of two plates and solid printing for concealment was applied to the transparent paper side, and raised printing to match the pattern was performed to the PP side. The plate configuration, ink, etc. are the same as in Example 1.

Next, a diallyl phthalate resin impregnating solution was applied to the transparent paper side of the composite sheet and dried. The sheet cut into predetermined dimensions was placed on a 4 m/m plywood board and hot-press molded through a smooth mirror plate.
The molding conditions were 130° C., 10 kg/cm ² for 10 minutes. The resulting Datup decorative board had a pattern on its surface that perfectly matched the embossment, and the entire surface had a unique matte state similar to the surface state of transparent paper, resulting in a highly decorative board.

To summarize the effects of the present invention: 1 Emboss can be expressed at low cost without using an expensive embossing plate.

2. Since it is an embossing method using printing means,
It is possible to express an emboss that perfectly matches the pattern. In addition, since the embossing is independent from the printing of the pattern, it is possible to freely design combinations with printing colors, and therefore, extremely varied designs can be expected.

3. The resulting decorative board has exactly the same apparent structure as a normal decorative board, and in particular, since there is a transparent protective layer on the surface, there is no inferiority in terms of physical properties.

This can be said to be an invention with extremely high practical value.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention.
The figure is a sectional view showing an integrated transparent sheet and a release layer, Figure 2 is a schematic diagram showing a method of providing a release layer on a transparent sheet, and Figure 3 is a sectional view of a composite sheet after the printing process has been completed. Figure 4 is a schematic diagram showing a method of coating and impregnating a thermosetting resin on the transparent sheet surface of a composite sheet, Figure 5 is a schematic diagram showing a method of molding a decorative board, and Figure 6 is a schematic diagram showing a method of molding a decorative board. FIG. 7 is a cross-sectional view showing the behavior, and FIG. 7 is a cross-sectional view showing the process of removing the release layer to obtain a decorative board. DESCRIPTION OF SYMBOLS 1... Transparent sheet, 2... Release layer, 3... Adhesive layer, 4... Transparent sheet, 5... Release layer, 6... Melted thermoplastic resin, 7... Transparent sheet, 8...
Release layer, 9... pattern printing, 10... raised printing,
11... Thermosetting resin solution, 12... Composite sheet, 13... Transparent sheet side, 14... Base material, 15
... Hiding layer, 16 ... Composite sheet, 17 ... Mirror plate, 18 ... Lower mirror plate, 19 ... Cushion,
20... cushion, 21... hot plate, 22... hot plate, 23... raised ink section, 24... specular plate,
25... Release layer, 26... Convex portion, 27... Transparent sheet, 28... Concave portion, 29... Base material, 30... Hiding layer, 31... Release layer, 32... Decorative board surface Recessed portion, 33... Decorative board.

Claims (1)

[Claims] 1. In a method for manufacturing a thermosetting resin decorative board, a transparent sheet that forms a surface protective layer of the decorative board and becomes substantially transparent after molding, and a release layer are laminated and integrated in advance. After that, an arbitrary pattern is printed on the surface of the transparent sheet by any printing means, and a raised print that matches or harmonizes with the pattern is applied to the surface of the release layer.
The printed composite sheet is placed on the base material with the transparent sheet facing the base material, if necessary, with the transparent sheet facing the base material, and after hot-pressure molding with a flat backing plate on top. , A method for producing a thermosetting resin decorative board having embossed recesses that match or harmonize with a pattern, characterized by removing a release layer. 2. The method for manufacturing a decorative board according to claim 1, wherein the transparent sheet is impregnated with a thermosetting resin and then integrated with a release layer. 3. Manufacture of a decorative board according to claims 1 to 2, characterized in that the transparent sheet and the release layer are integrated, printed, and then the transparent sheet is impregnated with a thermosetting resin. Method. 4. The release layer is a sheet-like material, and is integrated with the transparent sheet via an adhesive layer, and the adhesive layer is used to form the thermosetting resin decorative board during the molding stage of the intended thermosetting resin decorative board. 4. A method for manufacturing a decorative board according to claims 1 to 3, characterized in that a surface layer of the board is formed. 5. Claims 1 to 5, characterized in that the release layer is made of a thermoplastic resin, and the integration with the transparent sheet is performed by melting and solidifying the thermoplastic resin.
The method for producing a decorative board according to item 3. 6 Claims 1, 4, and 5 characterized in that the transparent sheet is not impregnated with thermosetting resin.
The method for manufacturing the decorative laminate described in Section 1.