JPH0978498A - Production of decorative paper or decorative plywood forming uneven pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a decorative paper, etc., forming uneven pattern, excellent in fully dressing property and solvent resistance by printing an arbitrary pattern with ink containing a photocurable suppressing agent onto the surface of decorative paper, applying an isocyanate-based compound, etc., thereon and curing the isocyanate-based compound. SOLUTION: An arbitrary pattern is printed onto the surface of decorative paper such as titanium paper or decorative plywood by ink containing a photocurable suppressing agent such as thiuram-based compound and further, an isocyanate based compound such as hexamethylene diisocyanate is applied thereon and successively, a coating material containing an ultraviolet curable resin such as unsaturated polyester resin as a main agent (preferably in coating amount of 80-120g/m<2> ) is applied thereto and coating film is cured by irradiating ultraviolet rays to the coating material to provide the objective decorative paper or decorative plywood forming uneven pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative paper or a decorative plywood on which an uneven pattern can be formed.

[0002]

2. Description of the Related Art In recent years, a decorative paper or a decorative plywood having a beautiful concavo-convex pattern formed on its surface by means of photoetching, mechanical embossing or the like has been manufactured. However, according to the conventional manufacturing method by photoetching, when printing a woodgrain pattern on a decorative paper such as titanium paper or thin paper or a laminated plywood with decorative paper, or printed plywood, a curing inhibitor is applied to the wood grain conduit portion. Print with the ink to be contained, apply UV curable paint from above and cure with an UV lamp, and due to the difference in the curing speed, the concave part will be formed in the conduit part, so the concave part of the wood grain conduit part will be insufficiently cured, so the concave part Has an appearance that is quite different from that of natural wood grain due to its too high luster, and has the disadvantage that the strength of the recess is small and the solvent resistance is poor.

As a solution to the above-mentioned drawbacks, a curing mechanism of an ultraviolet curable resin is used by using an ultraviolet curable coating in combination with a thermosetting catalyst or an isocyanate compound, that is, as disclosed in Japanese Patent Publication No. 54-15926. By applying a coating material containing an isocyanate-based compound having a curing function different from that of UV-curable resin, UV-curing is suppressed even after the UV-curing is completed, and the curing of the recesses that are insufficiently cured continues to proceed. A possible method is proposed.

[0004]

However, in the technique disclosed in Japanese Patent Publication No. 54-15926, although a beautiful decorative paper or a plywood having no unevenness in terms of gloss and strength can be obtained, solvent resistance or No consideration is given to the rate of development of solvent resistance, that is, the time taken for the solvent resistance effect to appear, and there is room for further improvement. Furthermore, in the technique disclosed in this publication, since an ultraviolet curable resin and an isocyanate compound are used in combination, there is no choice but to be constrained by working time depending on the pot life, and this point should be improved. . It is an object of the present invention to provide a method for manufacturing a decorative paper or a decorative plywood that can form a concavo-convex pattern that solves the above-mentioned problems under such a background.

[0005]

The inventors of the present invention have conducted extensive studies to overcome such problems, and as a result, have developed an arbitrary pattern with an ink containing a photocurable inhibitor on the surface of a decorative paper or a decorative plywood. Makeup that prints, then coats an isocyanate-based compound on top of it, then coats with a UV-curable resin as the main component, and irradiates UV rays to cure the coating film The present invention has been completed by finding that the method for producing paper or decorative plywood meets the above object.

That is, the ultraviolet curable resin undergoes a curing reaction by a radical reaction like an unsaturated polyester resin, for example, but if an isocyanate compound is applied (pre-coated) thereto in advance, the radical reaction is carried out simultaneously or subsequently. The urethane reaction proceeds between the hydroxyl group and the isocyanate group in the unsaturated polyester resin. The radical reaction of photopolymerization is much faster than the urethanization reaction.Therefore, the formation of the uneven pattern is predominantly performed by the radical reaction. As a result, a decorative paper or decorative plywood having excellent performance in which a beautiful concave-convex pattern is formed and the strength of concave portions is not reduced can be easily obtained. Further, by pre-coating with an isocyanate compound and then applying a paint, there is an effect that the surface of the convex portion is finished smoothly.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, first, an arbitrary pattern is printed on the surface of the decorative paper or the decorative plywood with an ink containing a photocuring inhibitor, and as the photocuring inhibitor, a polymerization inhibitor such as hydroquinone, Antioxidants such as phenol compounds, sulfur compounds, phosphorus compounds, thiuram compounds, and ultraviolet absorbers are used, and among them, thiuram compounds and ultraviolet absorbers are particularly preferable.

Next, an isocyanate compound is applied onto paper or plywood on which a pattern is printed with an ink containing the above-mentioned photocuring inhibitor, and then a coating material containing an ultraviolet-curable resin as a main component is applied. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI) for an aliphatic polyisocyanate, isophorone diisocyanate (IPDI) for an alicyclic system, hydrogenated diphenylmethane diisocyanate (H ₁₂ MDI), and tolylene diisocyanate (TDI) for an aromatic system. ), Xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), polyphenylmethane polyisocyanate (crude MDI) and the like, particularly preferably dimer compounds using diphenylmethane diisocyanate and polyphenylmethane polyisocyanate, buret structure Alternatively, it is used as a trimer compound having an isocyanurate structure, an addition reaction compound of a polyol, and various modified products by known methods.

The application of the isocyanate compound is not particularly limited, but the concentration at the time of application is 5 to 50, for example.
% By weight, preferably 10 to 30% by weight, coating amount 10 to
100 g / m ^2, preferably desired to be 20 to 50 g / m ^2. If the coating concentration is less than 5% by weight, the viscosity becomes low, and if it exceeds 50% by weight, the viscosity becomes high. Further, if the coating amount is outside the above range, the solvent resistance becomes poor and the unevenness becomes shallow, which is not preferable. The diluting solvent is preferably a polymerizable monomer such as vinyl acetate, styrene, methyl methacrylate, 2-ethylhexyl acrylate, but may be a general solvent such as ethyl acetate, toluene, methyl ethyl ketone.

As the ultraviolet curable resin used in the present invention, a hydroxyl group-containing radical reactive (ultraviolet curable) resin such as unsaturated polyester resin, acrylic resin or acryl-modified epoxy resin is used as a photosensitizer and a polymerizable compound. Mixtures of monomers and the like are prepared, and are prepared as a coating. Among them, a so-called wax type unsaturated polyester resin in which a wax is used in combination with an unsaturated polyester resin and a wax type resin in the air A so-called air-drying unsaturated polyester resin containing one component of an allyl ether compound of a polyhydric alcohol, which is a type that is rapidly cured in the above, is included.

The coating of the coating material is not particularly limited, but it is desired that the coating amount is, for example, 50 to 150 g / m ² , preferably 80 to 120 g / m ² . When the coating amount is outside the above range, the uneven pattern cannot be finished beautifully, which is not preferable.

In the present invention, it is important to apply the above-mentioned isocyanate compound and a coating material containing an ultraviolet curable resin as a main component in order, and then irradiate ultraviolet rays to cure the coating film. As a method of irradiating with ultraviolet rays, a high pressure mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp or the like is used.

Thus, the production method of the present invention, that is, a method for producing a decorative paper or a decorative plywood, which is most characterized by precoating an isocyanate compound and subsequently applying a coating material containing an ultraviolet-curable resin as a main component, Not only is a beautiful concavo-convex pattern formed with no difference in strength between the concave and convex portions,
It has a good solvent resistance effect development rate, and is an excellent method that is not restricted by the pot life. Furthermore, since it is precoated with an isocyanate-based compound, it also has the effect that the convex surface is finished smoothly. .

[0014]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, "part" and "%" mean weight basis unless otherwise specified. Example 1 A zelkova pattern was printed on thin paper with an ink containing 10% tetramethylthiuram disulfite as a photocuring inhibitor, which was applied to a 2.7 mm thick plywood board, and then printed on the upper surface of the printed surface. A solution comprising 90 parts of Polymeric MDI (manufactured by Nippon Polyurethane Co., Ltd .: Millionate MR) and 10 parts of vinyl acetate monomer as a diluent was applied by a roll coater at an application amount of 30 g / m ² , and then as an ultraviolet curable unsaturated polyester resin. , Goselac UV-200
70 parts (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and Gosselac UV
-260 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 30 parts, colloidal silica 1.0 part, paraffin wax (melting point 54 to 56)
° C.) 0.2 parts, and the coating consisting of 30 parts of styrene was coated at a coverage of 80 g / m ² at a flow coater. Thirty seconds later, the coated plywood was put on a fluorescent lamp for photopolymerization (40 w / piece, FL
Lamp, manufactured by Toshiba) for 1 minute, high pressure mercury lamp (80w / c)
m, HTQ lamp) for 3 seconds.

The coated plywood thus obtained had an uneven pattern in synchronism with the printed pattern and had a finish very close to that of natural wood, and there was no difference in the unevenness in terms of strength. or,
The surface of the convex portion (non-wood grain conduit portion) was smooth. Further, the rate of developing the solvent resistance effect was evaluated as follows, and the results are shown in Table 1.

(Release Rate of Solvent Resistance Effect) When performing a rubbing test on the obtained coated plywood with ethyl acetate, the time (days) required for no abnormalities to be observed even after 50 tests was determined.

Example 2 A decorative plywood was obtained in the same manner as in Example 1 except that the trimethylolpropane TDI adduct (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) was used instead of the polymeric MDI and styrene was used as the vinyl acetate monomer. It was Similar to Example 1, the obtained decorative plywood had a concavo-convex pattern formed in synchronism with the printed pattern, had a finish very close to that of natural wood, and had no difference in terms of strength. The surface of the convex portion (non-wood grain conduit portion) was smooth. Further, the development rate of the solvent resistance effect was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 The same procedure as in Example 1 was repeated except that the polymeric MDI was replaced with hexamethylene diisocyanate trimer (Coronate HX manufactured by Nippon Polyurethane Co.) and the vinyl acetate monomer was replaced with methyl methacrylate. Got Similar to Example 1, the obtained decorative plywood had a concavo-convex pattern formed in synchronism with the printed pattern, had a finish very close to that of natural wood, and had no difference in terms of strength. The surface of the convex portion (non-wood grain conduit portion) was smooth. Further, the development rate of the solvent resistance effect was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A decorative plywood was obtained in the same manner as in Example 1 except that the isocyanate compound coating step was omitted. The obtained decorative plywood was too glossy because the etched recesses were insufficiently cured, and the coating strength was also poor. Further, crater-like fine irregularities were observed on the surface of the convex portion (non-wood grain conduit portion). Further, the development rate of the solvent resistance effect was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 In Example 1, a solution containing 90 parts of polymeric MDI (manufactured by Nippon Polyurethane Co., Ltd .: Millionate MR) and 10 parts of vinyl acetate monomer as a diluent, and Goserac UV-as an ultraviolet curable unsaturated polyester resin. Two
00 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 30 parts of Gosselac UV-260 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 1.0 part of colloidal silica, paraffin wax (melting point 54 to 54).
(56 ° C.) Instead of successively applying a coating composition consisting of 0.2 parts of styrene and 30 parts of styrene, a mixture of 30 parts of the isocyanate compound and 80 parts of a coating material containing the UV-curable unsaturated polyester resin as a main component is printed. A decorative plywood was obtained in the same manner except that the coating was applied on the upper surface. The obtained decorative plywood became a cured coating film containing bubbles in some places. Further, crater-like fine irregularities were observed on the surface of the convex portion (non-wood grain conduit portion). Further, the development rate of the solvent resistance effect was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0021]

[Table 1]

[0022]

EFFECTS OF THE INVENTION The manufacturing method of the present invention not only forms a beautiful uneven pattern in which the strengths of the concave and convex portions are not different,
It is an excellent method that exhibits a good solvent resistance effect development rate and is not restricted by the pot life. Further, since the isocyanate-based compound is pre-coated, it has an effect that the surface of the convex portion is finished smoothly.

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[Procedure amendment]

[Submission date] September 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

However, in the technique disclosed in Japanese Patent Publication No. 54-15926, although a beautiful decorative paper or a plywood having no unevenness in terms of gloss and strength can be obtained, solvent resistance or No consideration is given to the rate of development of solvent resistance, that is, the time taken for the solvent resistance effect to appear, and there is room for further improvement. Further, in the technique disclosed in the publication, since an ultraviolet curable resin and an isocyanate compound are used in combination, there is no choice but to be restricted in work due to the pot life, and this point should be improved. . It is an object of the present invention to provide a method for manufacturing a decorative paper or a decorative plywood that can form a concavo-convex pattern that solves the above-mentioned problems under such a background.

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Claims (2)

[Claims] 1. An arbitrary pattern is printed on the surface of a decorative paper or a decorative plywood with an ink containing a photocuring inhibitor, and an isocyanate compound is further applied on the upper surface of the decorative paper or a UV curable resin as a main component. A method for manufacturing a decorative paper or a decorative plywood, which comprises applying a coating composition, and irradiating it with ultraviolet rays to cure the coating film. 2. The method according to claim 1, wherein the ultraviolet curable resin is an ultraviolet curable unsaturated polyester resin.