JPS61481A - Decorative sheet manufacturing method - Google Patents

Abstract

PURPOSE:To prepare a decorative sheet of which the recessed part is excellent in three-dimensionality and has no gloss, by applying a pattern to a substrate by using ink containing specific N-nitrosohydroxylamine salt and further applying an ultraviolet curable resin to said pattern before irradiating ultraviolet rays. CONSTITUTION:Patterns are applied to a substrate 1 by using ink 2 containing N-nitrosohydroxylamine salt represented by formula [wherein R is an alkyl group or an aryl group, (n) is 1-6 and M is an n-valent metal or ammonium]. Next, when an ultraviolet curable resin 3 is applied onto the patterns and irradiated with ultraviolet rays, the recessed parts following the patterns are formed to the cured resin layer. By this method, a decorative sheet having recessed parts deeply formed thereto and excellent in three-dimensionality and having no gloss in recessed parts can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a decorative sheet, and more particularly, to a method for manufacturing a decorative sheet having an uneven surface that is completely in sync with a printed pattern on a base material.

Conventionally, decorative decorative sheets with wood grain or geometric uneven patterns on their surfaces have been widely used as exterior panels for furniture, fittings, or electrical equipment, but these sheets are often manufactured by embossing. has been done. but,
According to such a mechanical method, it is difficult to form a pattern of convexes and convexes that closely match the pattern of the sheet, and there is also the problem that a large number of large-scale facilities are required, which increases manufacturing costs.

In order to solve such problems, for example,
No. 9-122553 discloses that a desired printing pattern is formed on a substrate using a printing ink composition containing a so-called curing inhibitor such as an ultraviolet absorber or a polymerization inhibitor, and an ultraviolet curable ink is applied on the substrate. A decorative sheet in which a resin composition is applied and each time the resin composition is irradiated with ultraviolet rays, depressions are created in the cured resin layer corresponding to the printed pattern, thus forming a three-dimensional uneven surface that is in sync with the printed pattern. A manufacturing method has been proposed.

In such conventional methods, as a curing inhibitor,
For example, conventionally known ultraviolet absorbers and polymerization inhibitors such as hensitriazole derivatives and quinones are used, but it is difficult to print on a substrate using a printing ink containing such curing inhibitors. When a pattern is applied and an uneven surface is formed on the cured resin layer as described above, the biggest problem is that the recesses formed corresponding to the printed pattern are still shallow.
It is cited that it lacks three-dimensionality.

In addition, in general, in natural precious wood, the conduit part of the tissue has less luster or luster than other parts, but it can be printed as a pattern using the above-mentioned printing ink containing a conventionally known hardening inhibitor. When a pipe (tube) is printed on a base material and a recess is formed in the cured resin layer corresponding to the printed pattern as described above, the recess becomes noticeably brighter or more glossy than other parts. As a decorative sheet with a wood grain pattern, there is a problem in that it gives a very unnatural impression.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to completely synchronize with the printed pattern on the base material, and to form a deep concave portion corresponding to the printed pattern, resulting in three-dimensional distortion.
A further object of the present invention is to provide a method for manufacturing a decorative sheet in which the recesses have substantially no luster or luster.

The method for producing a decorative sheet according to the present invention is carried out using the general formula (where R is an alkyl group, an aryl group, an alkylaryl group, or an arylalkyl group, n is a number from 1 to 6, and M is n
Indicates a valent metal or ammonium. ) represented by N-
A printing pattern is applied to a substrate using a printing ink composition containing a nitrosohydroxylamine salt, an ultraviolet curable resin composition is applied onto this substrate, and then ultraviolet rays are irradiated to form the printed pattern. It is characterized by forming recesses in the cured resin layer that are synchronized with the .

In the method of the present invention, the base material is not particularly limited, and for example, paper, resin sheets, wood boards, plywood, metal plates, etc. are used. Examples of the resin sheet include polyvinyl chloride resin, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl acetate, saturated polyester,
A sheet made of resin such as polyvinylitine chloride, acrylic resin, thermoplastic polyurethane resin, etc. is preferably used.

Such a resin sheet may contain various additives necessary depending on the resin, such as a plasticizer, a filler, a coloring agent, an antioxidant, and the like.

The printing ink used in the method of the present invention has the following general formula as a curing inhibitor, where R is an alkyl group, an aryl group, an alkylaryl group, or an arylalkyl group, n is a number from 1 to 6, and M is n
Indicates a valent metal or ammonium. ) represented by N-
Contains nitrosohydroxylamine salt.

In the above N-nitrosohydroxylamine salt, R is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, neopentyl, isoamyl, hexyl, isohexyl, heptyl, octyl, isooctyl, Alkyl groups such as 2-ethylhexyl, decyl, isodecyl, lauryl, tridecyl, mixed alkyl of C1□ to CI5, stearyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, 4-methylcyclohexyl, cycloalkyl groups, phenyl, naphthyl groups, etc. Aryl group, hensyl, β-phenylethyl, γ-phenylpropyl, β-phenylpropyl and other arylalkyl groups, tolyl, xylyl, ethylphenyl, butylphenyl, tertiary butylphenyl, octylphenyl, isooctylphenyl, tertiary octyl Examples include alkylaryl groups such as phenyl and nonylphenyl.

Examples of M include alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, metals such as aluminum and cerium, and ammonium.

The N-nitrosohydroxylamine salt is contained in the printing ink in an amount of 1 to 10% by weight, preferably 3 to 8% by weight.

If the content of this N-nitrosohydroxylamine salt is less than 1% by weight based on the printing ink, ultraviolet rays are applied to the ultraviolet curable resin composition layer applied on the printed pattern of the substrate by this printing ink. When irradiated, the effect of suppressing the curing of the resin composition layer corresponding to the printed pattern is poor, and therefore it is difficult to form deep recesses in the cured resin layer in synchronization with the printed pattern. On the other hand, the content is 1
When it is more than 0% by weight, the UV curable resin set above it from the printed pattern containing it! This is not preferable because the diffusion in the acid layer becomes excessive, and wide recesses are formed corresponding to the printed pattern, so to speak, the resolution is reduced.

According to the method of the present invention, since the printing ink contains the above-mentioned N-nitrosohydroxylamine salt as an effect inhibitor, printing with the printing ink is more effective than printing inks containing conventionally known effect inhibitors. Corresponding to the pattern,
It is possible to form significantly deeper four portions in the cured resin layer.

The printing ink used in the method of the present invention has a normal composition except that it contains the curing inhibitor, and contains an appropriate amount of pigment, for example, 10 to 15% by weight of a resin and 6 to 6 % of an organic solvent.
Contains 0 to 85% by weight.

According to the method of the present invention, after a desired printing pattern is printed on a substrate using such a printing ink, an ultraviolet curable resin composition is applied thereon.

The ultraviolet/ray curable resin composition that can be preferably 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, dye and pigment, It is a resin composition that contains fillers and the like, and is usually crosslinked and cured within a few seconds when exposed to ultraviolet rays. As the film-forming component, a high molecular weight polymer, oligomer, monomer, or the like having an acryloyl group, a methacryloyl group, or other addition-polymerizable double bonds in the molecule is usually used. In the present invention, polyester (meth)acrylate, polyurecne (meth)acrylate-1-, epoxy (methacrylate), and the like are preferably used as such coating film-forming components.

The reactive diluent is blended to reduce the viscosity of the film-forming component to make it coatable, and to crosslink and network the film-forming component when exposed to ultraviolet rays. , a polyfunctional oligomer or monomer. However, it can also be used by itself as a film-forming component. In the present invention, monomers having two or more acrylate groups and/or methacrylate groups in the molecule are preferably used as such reactive diluents, and specific examples thereof include trimethylolpropane tri(meth)acrylate. , penquerythritol tri(meth)acrylate, butanediol di(meth)acrylate, inopentyl glycol di(meth)acrylate, 1,6-hexanethiol di(meth)acrylate, diethylene glycol di(meth)acrylate, etc. can. Furthermore, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, N
-vinyl-2-pyrrolidone, tetrahydrofurfuryl (
Monofunctional monomers such as meth)acrylates can be used in combination. Further, as the photopolymerization initiator, hensyl, hensyphenone, benzoin ether, chlorothioxanthone, jetoxyacetophenone, hensyl dimethyl ketal, etc. are usually used.

The amount of each component in the ultraviolet curable resin composition as described above is usually about 20 to 90% by weight, preferably 40 to 70% by weight of the film-forming component, and about 1% by weight of the reactive diluent.
The content is 0 to 80% by weight, preferably 30 to 60% by weight, and the photopolymerization initiator is about 0.5 to 10% by weight, and the above-mentioned components are further blended as necessary.

In the method of the present invention, UV-curable unsaturated polyester resin compositions can also be preferably used. This resin composition usually contains unsaturated dibasic acids such as maleic acid, fumaric acid, and itaconic acid or their anhydrides, and optionally phthalic anhydride, tetrahydrophthalic anhydride, hexahydrofucric anhydride, and succinic anhydride. acid, a dibasic acid component consisting of a saturated dibasic acid such as adipic acid, and cehatic acid;
Reaction products with polyhydric alcohols such as triethylene glycol, neopentyl glycol, pentaerythritol, and trimethylolpropane are used as film-forming components. A photosensitizer and, if necessary, higher fatty acids such as tung oil, linseed oil, dehydrated castor oil, and soybean oil, polymerizable monomers, other fillers, pigments, etc. are blended into this to form an ultraviolet curable resin composition. is formed. It is also possible to use urethane-modified polyester resins in which unsaturated polyester is partially substituted with tolylene diisocyanate, methylene diisocyanate, etc., or epoxy-modified resins.

Next, according to the present invention, this ultraviolet curable resin composition layer on the base material is irradiated with ultraviolet rays to form deep recesses in the cured resin layer corresponding to the printed pattern.

The ultraviolet rays may be irradiated by any conventional method known in the art, for example, by using an ultraviolet source such as a xenon lamp, a low pressure, medium pressure, high pressure, or ultra-high pressure mercury lamp. The ultraviolet rays may be irradiated in an amount sufficient to fully cure the ultraviolet curable resin composition, and are appropriately selected depending on the composition.
In the case of a W/cm mercury lamp, irradiation may be performed for 1 second to several seconds.

FIG. 1 shows a sectional view of a main part of a base material 1 before irradiation with ultraviolet rays in the method of the present invention, and a desired printed pattern 2 is formed on this base material with a printing ink containing the curing inhibitor. Further, a resin layer 3 made of the above-mentioned ultraviolet curable resin composition is formed thereon. In such a resin layer, the mechanism is not necessarily clear, and the present invention is not limited by any theory, but as shown in the figure, the curing inhibitor 4 of the printed pattern 2 is The resin layer 3 is diffused toward the surface side along the printed pattern, and is included in the resin layer along the printed pattern.

As a result, by irradiating such a resin layer with ultraviolet rays, as shown in FIG. 2, the crosslinking of the resin layer in the portion 5 along the printed pattern is delayed, but the other portion 6 is quickly crosslinked. do. That is, the resin layer that does not correspond to the printed pattern is quickly cured by ultraviolet irradiation and becomes three-dimensional, but the portion 5 of the resin layer in which the curing inhibitor has been diffused is delayed in curing and forms the recess 7, thus preventing the printing. A cured resin layer 8 is formed having an uneven surface that perfectly matches the pattern. Furthermore, the recesses thus formed are less shiny or shiny than other parts.

As described above, according to the method of the present invention, a printing pattern is applied to a substrate using a printing ink containing the above-mentioned curing inhibitor N-nitrosohydroxylamine salt, and an ultraviolet curable resin composition is applied on the substrate. is coated and then irradiated with ultraviolet rays, so the curing of the resin layer corresponding to the printed pattern is significantly delayed, and as a result, deeper recesses than ever are formed in the resin layer corresponding to the printed pattern, thus The concavo-convex pattern formed is completely in sync with the printed pattern and has a three-dimensionality.

Moreover, this recessed portion has substantially no grain or luster, and, for example, when a conduit portion in a wood grain pattern is formed into a recessed portion in this way, it has a natural three-dimensionality comparable to that of natural precious wood. Furthermore,
Since the printed pattern is covered with a cross-linked and cured resin layer, it has desirable properties as a decorative sheet, such as excellent heat resistance, abrasion resistance, and strength.

The method for producing a decorative sheet according to the present invention will be described below with reference to Examples.

Example 1 A 0.1-thick hinyl chloride resin sheet containing 20 parts by weight of plasticizer per 100 parts by weight of resin was used as the base material, solid printing was performed on this sheet with ordinary gravure ink, and then wood grain was printed. After printing the pattern, a pattern representing the conduit portion was printed using a printing ink containing a hardening inhibitor (not shown in the table). An ultraviolet curable resin composition containing trimethylolpropane trimethacrylate as a film-forming component was applied onto this printed pattern to a thickness of 20 μm. Next, this resin layer was irradiated with ultraviolet rays for 1 second using a mercury lamp with an output of 80 W/cm to harden the resin layer and form an uneven surface.

Further, as a comparative example, a resin layer was cured in the same manner as above except that a conventional printing ink containing a polymerization inhibitor was used.

The depth of the recesses on each of the uneven surfaces formed as described above, that is, the degree of rotation, was measured using a contracer, and the curls or gloss of the recesses were visually observed. The results are shown in the table. In addition, in the gloss evaluation in the table, ○ indicates that the recessed part is not as shiny as other parts, △ indicates that it is slightly glossy, and × indicates that it is more glossy than other parts. .

As is clear from the table, according to the method of the present invention, deep concave portions are formed corresponding to the printed pattern, and the four parts of the plate do not have burrs or gloss.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing the base material, the printed pattern thereon, and the ultraviolet curable resin composition layer, and FIG. 2 is a cross-sectional view of the main part showing the base material, the printed pattern thereon, and the ultraviolet curable resin composition layer. FIG. FIG. 3 is a sectional view of a main part of the formed decorative sheet. ■... Base material, 2... Printed pattern, 3... Ultraviolet curable resin composition layer, 4... Curing inhibitor, 7... Concave portion,
Death: Cured resin layer. Patent Applicant Band-Kagaku Co., Ltd. Agent Patent Attorney Ittsu Makino Department Figure 1 Figure 2

Claims (2)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, R is an alkyl group, aryl group, alkylaryl group, or arylalkyl group, n is a number from 1 to 6, M is n
Indicates a valent metal or ammonium. ) A printing pattern is applied to a substrate using a printing ink composition containing an N-nitrosohydroxylamine salt represented by the following formula, an ultraviolet curable resin composition is applied onto this substrate, and then ultraviolet rays are irradiated onto the substrate. A method for producing a decorative sheet, comprising: forming concave portions in the cured resin layer that match the printed pattern. (2) The method for producing a decorative sheet according to claim 1, wherein the N-nitrosohydroxylamine salt is an N-nitrosophenylhydroxylamine aluminum salt.