JPH09290487A - Surface-reinforced decorative paper and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy hardness and wear resistance which can be used for upholstery and appliances by constituting the first protective layer and the second protective layer each with an active energy rays-curable water-based resin compsn. with a specified compsn. SOLUTION: As the first protective layer and the second protective layer respectively comprise active energy rays-curable water-based resin compsn. with excellent affinity with a water-based ink, adhesive properties between each protective layer and the water-based ink layer are improved to be able to provide hardness and wear resistance which can be used for upholstery, etc. One ingredient of the active energy rays-curable water-based compsn. is constituted of a resin consisting of an ultraviolet rays- or electron beam-curable polymer, oligomer or monomer and as at least one ingredient thereof, a bifunctional or higher urethane acrylate or urethane methacrylate of formula (wherein R is a hydrogen atom or a methyl group and X is an isocyanate residue and Y is a dihydric alcohol residue) is incorporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-reinforced decorative paper for decorative boards used for furniture, housing equipment and the like and a method for producing the same, and in particular, it has high surface hardness and excellent durability, and The present invention relates to a surface-reinforced decorative paper for high-grade decorative boards, which can reduce production costs and avoid environmental hygiene problems, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a decorative paper for a decorative board laminated on a flat surface of a decorative substrate such as phenol core paper or particle board and used as a decorative sheet for furniture and housing equipment, a base paper having good permeability such as titanium paper has hitherto been used. After printing on (decorative paper substrate),
A resin-impregnated paper made by impregnating a thermosetting resin such as melamine resin or diallyl phthalate resin into this decorative paper base is known, and this resin-impregnated paper is used as a flat surface of a decorative substrate such as the phenol core paper or particle board. Put it on, and
A decorative plate is manufactured by heating and compressing it through a mirror plate. And the decorative board obtained by such a method has necessary surface hardness and abrasion resistance, but on the other hand, it has to be expensive because of poor production efficiency.

[0003] In order to improve the production cost, various methods have recently been studied in which an electron beam-curable resin formulated as a solvent-free resin is used instead of a thermosetting resin such as a melamine resin. However, in reality, satisfactory results have not been obtained for the following reasons.

First, oil-based ink has been conventionally used as an ink for applying a print pattern to the decorative paper substrate, but in recent years, problems such as use of a solvent and influence on the global environment have been emphasized. Therefore, water-based inks that do not have such problems are becoming mainstream.

When a water-based ink is used instead of the oil-based ink, a solvent-free electron beam curable resin is applied from the surface of a decorative paper substrate having a printed pattern, and electron beam irradiation is performed in the same process. If you try to do so in a short time, the penetration of the electron beam curable resin is likely to be hindered due to the high polarity of the water-based ink,
There is a drawback that the electron beam curable resin is cured before the electron beam curable resin has fully penetrated into the decorative paper substrate.

Therefore, the adhesive force between the electron beam curable resin layer and the water-based ink layer is small, and further, the curing shrinkage of the electron beam curable resin layer also acts so that the electron beam curable resin is easily peeled from the surface of the ink layer. There was a problem.

In addition, the active energy ray-curable solventless paints and inks that utilize energy such as electron beams and ultraviolet rays as described above to cure the resin are generally The advantages such as energy saving, high productivity, and low temperature curing are emphasized. However, the active energy ray-curable solventless resin composition used here,
Generally, a 100% liquid type or organic solvent solution type resin composition which is mainly composed of an oligomer (or a prepolymer) and a monomer and which is further added with a photopolymerization initiator and a sensitizer in photocuring is applied. However, the deterioration of the work environment due to the odor caused by the use of low-molecular weight vinyl monomers for adjusting viscosity and solvents used to facilitate this coating workability, the risk of fire due to ignition of the monomers and solvents, toxicity, etc. There were many safety and health problems. Further, in the case of the 100% liquid type, there was a drawback that the physical properties of the originally intended oligomer were impaired by the addition of the monomer. For this reason, there is a demand for development of a surface-reinforced decorative paper to which a water-based ultraviolet or electron beam-curable resin composition which does not require a monomer or a solvent and has no problem is applied.

Further, the surface protective coating agent applied to the surface of the decorative paper substrate is required to have a good balance between surface design and physical properties. Then, an extender pigment such as inorganic filler particles is generally added in order to make the surface gloss be matte, but this extender pigment also contributes to the improvement of physical properties such as abrasion resistance in addition to the effect of the above matte feel. are doing. However, some products are required to have high surface gloss (that is, low matte feeling) and excellent physical properties such as abrasion resistance. In such a case, it is difficult to add a lot of extender pigment to the surface protection coating agent, and therefore it is necessary to satisfy the physical properties only with the resin component which is the main component of the surface protection coating agent.

However, even if the degree of cross-linking of the resin which is an organic substance is increased, when compared at the same film thickness, it is generally inferior to the physical properties of the coating film to which the inorganic substance is added, and the above-mentioned matte feeling is low and It was difficult to satisfy both physical properties such as abrasion resistance.

That is, there is a problem that it is difficult to satisfy both the surface design and the high-level coating film physical properties at the same time with only one surface protective coating layer.

[0011]

SUMMARY OF THE INVENTION The present invention has been made by paying attention to such problems, and the problem is that it has hardness and wear resistance that can be used for furniture and housing equipment. Moreover, it is an object of the present invention to provide a surface-reinforced decorative paper for a high-grade decorative board and a method for manufacturing the same, which can reduce the production cost and avoid environmental hygiene problems.

[0012]

That is, the invention according to claim 1 is premised on a surface-reinforced decorative paper for a decorative board to be laminated on a decorative substrate, and a decorative paper base provided with a print pattern by an aqueous ink. And an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component, which is provided on the printed surface of the decorative paper substrate and prepared so as not to have tackiness after heat drying. A first protective layer, and a second protective layer provided on the first protective layer and composed of an active energy ray-curable aqueous resin composition that does not contain the aqueous emulsion resin. It is a thing.

According to the surface-reinforced decorative paper according to the first aspect of the present invention, the active energy ray-curable aqueous resin composition having the first protective layer and the second protective layer excellent in affinity with the aqueous ink. Since it is composed of the above, the adhesion between each protective layer and the water-based ink layer is improved, and the active energy ray-curable water-based resin composition is applied to the inside of the decorative paper substrate in the heat drying process before curing the active energy ray. Since the material penetrates, it becomes possible to provide the furniture and the housing equipment with hardness and wear resistance.

Further, since the above-mentioned first protective layer is composed of an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component, which is prepared so as not to have tackiness after thermal drying, after thermal drying The coating film of is low in redissolvability in water. Therefore, it becomes possible to secure recoatability when the second protective layer is formed by coating the active energy ray-curable aqueous resin composition containing no aqueous emulsion resin in the subsequent step.

Further, a filler such as an extender pigment is added at a high concentration in the first protective layer composed of an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component to improve its abrasion resistance. On the other hand, the second protective layer composed of an active energy ray-curable aqueous resin composition containing no physical property of an aqueous emulsion resin is provided with its design property without adding a filler, thereby protecting the surface. It is possible to simultaneously satisfy the surface design and the high-level coating film physical properties, which were difficult to achieve with only one coating layer.

When a bifunctional or higher functional urethane acrylate or urethane methacrylate is blended in the active energy ray-curable aqueous resin composition, the urethane acrylate or urethane methacrylate reacts with other polymerizable resin composition components and is resistant. Solvent resistance, water resistance, acid resistance,
It becomes possible to form a protective layer having an excellent balance of physical properties such as alkali resistance and film strength. The invention according to claim 2 is made for such a technical reason.

That is, the invention according to claim 2 is premised on the surface-reinforced decorative paper according to claim 1, wherein one component of the active energy ray-curable aqueous resin composition is an ultraviolet or electron beam-curable polymer. A resin composed of an oligomer or a monomer, and at least one component of which contains a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the following general formula (I). is there.

[0018]

Embedded image R: hydrogen atom or methyl group X: isocyanate residue Y: dihydric alcohol residue

According to the surface-reinforced decorative paper according to the second aspect of the present invention, the above-mentioned general formula (I) having an acryloyl group or a methacryloyl group at both ends in the active energy ray-curable aqueous resin composition is used. Since the indicated bifunctional or higher functional urethane acrylate or urethane methacrylate is contained, after the coating film of the active energy ray-curable aqueous resin composition for the first and second protective layers is formed, ultraviolet rays, electron beams, etc. are formed. By irradiating with the active energy ray of, the bifunctional or higher functional urethane acrylate or urethane methacrylate reacts with other polymerizable resin composition components to act as one component of the cross-linking agent, and has solvent resistance, water resistance, acid resistance and resistance It becomes possible to form each protective layer having a good balance of physical properties such as alkalinity and film strength, and in the final protective layer coating film, Reaction components nor remain.

The dihydric alcohol residue of the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the above general formula (I) is ethylene oxide (E).
O) and a compound selected from ether-based polyols having a structure of propylene oxide (PO) as a raw material, and further, a composition per each repeating unit structure of ethylene oxide and propylene oxide constituting the dihydric alcohol residue By setting the ratio (molar ratio) in an appropriate range, the hydrophilicity / hydrophobicity of urethane acrylate or urethane methacrylate can be balanced, so that emulsifying ability with respect to other resin composition components is provided, and the oil-soluble compound is originally used. Can be effectively dispersed in water with other active energy ray-curable oligomers, monomers and the like, which are overwhelmingly different. As a result, since the urethane acrylate or urethane methacrylate itself acting as an emulsifier also acts as a cross-linking agent, it is possible to form a protective layer having an excellent balance of physical properties such as solvent resistance, water resistance, acid resistance, alkali resistance, and film strength. Becomes The inventions according to claims 3 and 4 have been made for such technical reasons.

That is, the invention according to claim 3 is premised on the surface-reinforced decorative paper according to the invention according to claim 2, and is a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the general formula (I). The polyhydric alcohol residue is composed of a compound selected from ether polyols having a structure of ethylene oxide and propylene oxide as a raw material, and the invention according to claim 4 is the invention according to claim 3. Based on such surface-reinforced decorative paper, the composition per repeating unit structure of ethylene oxide and propylene oxide forming the dihydric alcohol residue of the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the general formula (I). The ratio (molar ratio) is
It is characterized in that it is set in the range of 9: 1 to 4: 6.

Next, the invention according to claims 5 to 8 is defined by claim 1.
The present invention relates to an invention that specifies a method for producing a surface-reinforced decorative paper according to the described invention.

That is, the invention according to claim 5 is premised on the method for producing a surface-reinforced decorative paper according to claim 1, on the printing surface of a decorative paper substrate provided with a print pattern of an aqueous ink,
A first protective layer is formed by applying an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component, which is prepared so as not to have tackiness after heat drying, and on the first protective layer. The active energy ray-curable aqueous resin composition containing no aqueous emulsion resin is applied to form a second protective layer, and each protective layer is heat-dried and then irradiated with ultraviolet rays or electron beams. It is characterized in that the first protective layer and the second protective layer are simultaneously cured.

The invention according to claim 6 is premised on the method for producing the surface-reinforced decorative paper according to claim 5, wherein one component of the active energy ray-curable aqueous resin composition is an ultraviolet or electron beam-curable polymer. A resin composed of an oligomer or a monomer, and at least one component of which contains a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the following general formula (I):

[0025]

Embedded image R: hydrogen atom or methyl group X: isocyanate residue Y: dihydric alcohol residue

The invention according to claim 7 is based on the method for producing a surface-reinforced decorative paper according to claim 6, and has the above general formula (I).
Wherein the dihydric alcohol residue of a bifunctional or higher functional urethane acrylate or urethane methacrylate is composed of a compound selected from ether polyols having a structure of ethylene oxide and propylene oxide as a raw material, The invention according to claim 8 is based on the method for producing a surface-reinforced decorative paper according to claim 7, and is a dihydric alcohol residue of a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the general formula (I). The composition ratio (molar ratio) of each repeating unit structure of ethylene oxide and propylene oxide constituting the group is 9: 1.
It is characterized in that it is set in the range of to 4: 6.

[0027]

Embodiments of the present invention will be described below in detail.

The constituent materials of the surface-reinforced decorative paper will be described first, and then the method for producing the active energy ray-curable aqueous resin composition applied as the surface protective layer of the decorative paper will be described in detail.

First, as a decorative paper base material forming a part of the surface-reinforced decorative paper according to the present invention, the basis weight is 30 to 120 g /
m ² decorative paper base paper is preferred. A base paper for decorative paper, which has been previously subjected to a sealer treatment with a urethane resin or a vinyl resin, may be applied. This is printed with an aqueous ink or the entire surface is colored. The printing method may be a known method such as a gravure printing method. The coating method of the first and second protective layers is arbitrary, but in the production stage, a roll coater, a reverse roll coater, a gravure coater, a knife coater or the like is generally used.

Next, a method for producing the active energy ray-curable aqueous resin composition which is a constituent component of the first protective layer and the second protective layer will be described.

First, as the diisocyanate compound for introducing the polyurethane diol component in the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the above general formula (I), tolylene diisocyanate (TDI) and xylylene diisocyanate (XDI) are used. ), Diphenylmethane diisocyanate (MD
I), aromatic diisocyanates typified by naphthylene diisocyanate (NDI), lysine diisocyanate methyl ester (LDIM), trimethylhexamethylene diisocyanate (TMDI), dimer acid diisocyanate (DDI), hexamethylene diisocyanate, methylcyclohexylene -2,4 (2,6) -diisocyanate, aliphatic diisocyanates such as 1,3 (4)-(diisocyanatomethol) cyclohexane, 4,4-bis (isocyanatocyclohexyl) methane, and isophorone diisocyanate can be used. .

As the polyol substance for introducing the polyurethane diol component, ethylene glycol, propylene glycol, diethylene glycol,
Low molecular weight polyols such as dipropylene glycol, oligomer polyols such as polyoxyethylene glycol and polyoxypropylene glycol, and, if necessary, random or block polyethers of ethylene oxide and propylene oxide can also be used.

Next, an acrylate or a methacrylate is introduced into both terminals of the polyurethane diol obtained from the diisocyanate compound and the polyol substance to synthesize the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the above general formula (I). As a material for this, a bifunctional monomer having a methacryloyl group and an isocyanate group in one molecule, m-isopropenyl-α, α dimethylbenzyl isocyanate (m
-TMI), 2-methacryloyloxyethyl isocyanate (MOI) and the like. In addition to the various diisocyanate compounds exemplified above, an isocyanate group and an acryloyl or methacryloyl group and an active hydrogen group such as a hydroxyl group, a carboxyl group, an amine and an amide in an isocyanate group and a molecule of an arbitrary difunctional or higher polyfunctional polyisocyanate compound, respectively. Compounds having at least one or more isocyanate groups and one or more acryloyl or methacryloyl groups in one molecule obtained by reacting an active hydrogen group of one or more compounds can be used. Compounds having at least one acryloyl or methacryloyl group and at least one active hydrogen group such as a hydroxyl group, a carboxyl group, an amine, or an amide in a molecule required for synthesizing the compound are available in a wide variety of products of various grades. It is available as a commercial product. Typically,
For example, as anionic monomers, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, methacrylic acid,
Examples include itaconic acid, crotonic acid, and any oligomers containing these compounds as a copolymer component. Examples of the cationic monomer include amide monomers such as aminoalkyl acrylate and aminoalkyl methacrylate, acrylamide, N-methylolacrylamide, dimethylaminopropyl (meth) acrylamide, and N-isopropylacrylamide.

Further, as the other component of the active energy ray-curable aqueous resin composition containing the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the above general formula (I), a general polyester type is used. Polymerizable prepolymers represented by acrylates such as polyepoxy type, polyurethane type, polyether type, and polyacrylic type can be used. If necessary, monofunctional and polyfunctional acrylates or methacrylates having low odor and skin irritation may be added.

When the active energy ray in the active energy ray-curable aqueous resin composition is ultraviolet rays, it is necessary to add a photosensitizer (radical polymerization initiator) into the composition. Examples of such additives include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Benzoin such as benzyl methyl ketal and its alkyl ethers; acetophenone, 2,2-dimethoxy-
Acetophenones such as 2-phenylacetophenone and 1-hydroxycyclohexylphenylketone; anthraquinones such as methylanthraquinone, 2-ethylanthraquinone and 2-amylanthraquinone; thioxanthones, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone Thioxanthones; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone and 4,4-bismethylaminobenzophenone; and azo compounds. These can be used alone or 2
Tertiary amines such as triethanolamine and methyldiethanolamine; photoinitiating aids such as benzoic acid derivatives such as 2-dimethylaminoethylbenzoic acid and ethyl 4-dimethylaminobenzoate; It can also be used in combination with. The amount of the organic peroxide or photopolymerization initiator used is 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the polymerizable component of the active energy ray-curable aqueous resin composition. .

Although the main constituent materials of the surface-reinforced decorative paper according to the present invention have been described, the method for producing the above active energy ray-curable aqueous resin composition will be specifically described below.

First, in the synthesis of the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the above general formula (I), an arbitrary bifunctional polyisocyanate and ethylene oxide (EO) or propylene oxide (PO) are used. Choose a polyether diol with a structure,
According to a conventional method, these are formulated in a suitable solvent so that the ratio of isocyanate groups to hydroxyl groups becomes approximately equimolar, and they are reacted. In this case, it is preferable to formulate the composition so that the composition ratio (molar ratio) of EO and PO is in the range of 9: 1 to 4: 6.

In order to make the hydroxyl groups at both ends of the polyurethane diol obtained here be an acryloyl group or a methacryloyl group, (1) m-isopropenyl-α which is a bifunctional monomer having a methacryloyl group and an isocyanate group in one molecule. , Α-dimethylbenzylisocyanate (m-TMI), 2-methacryloyloxyethylisocyanate (MOI), or (2) an acryloyl or methacryloyl group in the molecule with the isocyanate group of any polyfunctional polyisocyanate compound having two or more functional groups. At least one isocyanate group and one or more acryloyl in one molecule obtained by reacting a group with an active hydrogen group of a compound having at least one active hydrogen group such as a hydroxyl group, a carboxyl group, an amine and an amide. Or A compound having a acryloyl group,
By reacting 2 moles with 1 mole of the polyurethane diol, a bifunctional or higher functional urethane acrylate or urethane methacrylate can be obtained.

Next, the urethane acrylate or urethane methacrylate obtained by the above-mentioned method is used as an essential component, and a general polymerizable prepolymer and, if necessary, monofunctional and polyfunctional compounds having low odor and skin irritation are used. An active energy ray-curable aqueous resin composition is obtained by blending acrylate or methacrylate monomers and forcibly emulsifying and dispersing this composition in water. In this case, the bifunctional or higher functional urethane acrylate or urethane methacrylate prepolymer represented by the general formula (I) acts as an emulsifier. When ultraviolet rays are used as the active energy rays, it is preferable that the oil-soluble photopolymerization initiator is added to the resin composition before or after emulsification, and that the water-soluble photopolymerization initiator is added after the emulsification.

The emulsification method conforms to the general forced emulsification method.
For example, (1) water is added after mixing all the resin components, and if necessary, a heating operation or a resin solvent is added,
Disperse strongly with a homomixer or the like. After the dispersion, cooling and solvent removal are performed. (2) First, after dissolving or dispersing urethane acrylate or urethane methacrylate represented by the above general formula (I) acting as an emulsifier in water, the remaining resin composition is gradually added while performing strong stirring. . (3) It can be produced by a general phase inversion emulsification method or the like.

Thus, the active energy ray-curable aqueous resin composition for the second protective layer is obtained. When this active energy ray-curable aqueous resin composition is used as the constituent material of the first protective layer, Is a general-purpose water-based resin such as an acrylic resin emulsion, a polystyrene-based resin emulsion, or a vinyl acetate-based resin emulsion as described below in order to prevent tackiness (that is, to be tack-free) after heat drying. , Vinylidene chloride resin emulsion, vinyl polymer emulsion such as vinyl chloride resin emulsion, synthetic rubber resin emulsion such as SB resin emulsion, NB resin emulsion, urethane resin emulsion, water dispersion of acrylic urethane resin emulsion, etc. Mold resin must be added as an antiblocking agent. It is. Also, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose,
Water-soluble resins such as hydroxyethyl cellulose, polyacrylic acid, casein, gelatin, starch, polyvinylpyrrolidone, polyacrylamide and their derivatives can also be used as necessary as additives for adjusting coating liquid physical properties such as thickeners. it can. Furthermore, an active energy ray-curable aqueous resin that is commercially available can also be used as a mixture.

Further, in order to impart various functions to the protective layer, the above active energy ray-curable aqueous resin composition,
If necessary, colorants, extender pigments, lubricants, plasticizers, stabilizers, flame retardants, defoamers, antioxidants, bactericides, conductive materials,
It is also possible to include additives such as magnetic materials.

[0043]

Embodiments of the present invention will be specifically described below.

All parts and% are based on weight unless otherwise specified.

[Example 1] "Synthesis of active energy ray-curable aqueous resin composition" Step 1 250 parts of 2-butanone and 100 parts of toluene were placed in a glass reaction vessel equipped with a calcium chloride tube, and 254 parts of diphenylmethane diisocyanate were added. Was charged in the mixed solvent, and then a mixed solution of 75 parts of diethylene glycol and 40 parts of dipropylene glycol was added dropwise over about 2 hours to give 20
A time reaction was performed.

At the final stage of the reaction, 5 parts of dipropyl alcohol was added dropwise to terminate the reaction, and 0.2 part of hydroquinone was added to randomly incorporate the structures of ethylene oxide and propylene oxide at a ratio of about 7/3. A polyurethane diol was obtained.

Step 2 Next, the polyurethane diol solution obtained in Step 1
-60 parts of methacryloyloxyethyl isocyanate was added and reacted at 60 ° C, and then the solvent was removed to obtain a bifunctional urethane methacrylate prepolymer. The disappearance of the absorption due to the isocyanate group was confirmed by IR spectrum measurement.

Step 3 50 parts of the bifunctional urethane methacrylate prepolymer obtained in step 2 was dispersed in 465 parts of distilled water that had been subjected to ion exchange treatment, and the temperature was kept at 50 ° C. A prepolymer composition comprising a light- or electron-beam-curable oligomer and a monomer having the following formulation was added to this aqueous dispersion little by little while sufficiently dispersing with a homomixer.

The prepolymer composition having the following formulation is 50
The mixture was heated to ° C. and charged with the viscosity lowered. After completion of the charging, stirring with a homomixer was continued at a rotation speed of 6000 rpm for 10 minutes to obtain a milky white uniform ultraviolet-curable aqueous resin composition.

6-functional urethane acrylate oligomer (Actilane 110, manufactured by AKCROS CHEMICALS) 160 parts PO, ECH-modified bisphenol A diacrylate (epoxy ester 3002A, manufactured by Kyoeisha Chemical Co., Ltd.) 40 parts Darocur 1173 (manufactured by Ciba Geigy) 7.5 parts

Step 4 The ultraviolet-curable aqueous resin composition obtained in Step 3 (hereinafter,
(Abbreviated as aqueous UV emulsion) was used to prepare an ultraviolet curable aqueous coating agent as the first and second protective layers with the following formulation.

(UV-Curable Aqueous Coating Agent for First Protective Layer) Aqueous UV emulsion 300 parts Acrylic urethane resin emulsion (NeoPac R-9000: manufactured by Zeneca) 320 parts Commercial UV-curable aqueous resin (NeoRad NR-440: Zeneca) 160 parts Silica powder (Mizukasil P-510: Mizusawa Chemical Co., Ltd.) 20 parts Colloidal silica (Cataloid SI-30: manufactured by Catalysis Co., Ltd.) 200 parts Silica was dispersed by the homomixer used in step 2. A coating consisting of a milky white stable suspension was obtained.

(UV-Curable Aqueous Coating Agent for Second Protective Layer) Aqueous UV emulsion 420 parts Polyether-modified silicone (Kp-341: manufactured by Shin-Etsu Chemical Co., Ltd.) 3.5 parts Water-soluble photopolymerization initiator (Irgacure 2959: Ciba Geigy Co., Ltd.) 4 parts A coating composition comprising a milky white stable suspension similar to the UV-curable aqueous coating agent for the first protective layer was obtained.

[Preparation of surface-reinforced decorative paper and decorative board] An oak-grained grain pattern is printed on a decorative paper base material having a basis weight of 60 g / m ² using a water-based ink (manufactured by Toyo Ink Mfg. Co.), and this decorative paper base is used. On the ink layer of the material, first apply the UV-curable water-based coating agent for the first protective layer with a wire bar to a coating amount of about 8 g / m ² , and dry in an oven at 75 ° C for 2 minutes. I did.

Next, a UV-curable aqueous coating agent for the second protective layer was applied to the surface of the first protective layer after thermal drying so that the coating amount was about 7 g / m ² , and the same as the first protective layer. Thermal drying was performed under the conditions.

Then, the above-mentioned coating films for the first and second protective layers were cured by irradiating the surface of the second protective layer with ultraviolet rays having an integrated light amount of 300 mJ / cm ^{2 with} a high pressure mercury lamp of 80 W / cm, and the surface gloss was measured. A good, hard, and tough film was obtained.

The decorative paper obtained here was pasted with a particle board using a urea / vinyl acetate adhesive to prepare a decorative board. Observation of the decorative board revealed a beautiful matte coating on the external surface. The scratch resistance was also good.

<Evaluation of Decorative Board> The performance of the decorative board obtained by the above method was evaluated by the following method.

1) Solvent resistance: 2-butanone was dropped on the surface of the decorative plate, and rubbing was performed under a load of 500 g / cm ² to observe the damage on the surface of the coating film by the solvent.

Then, the number of times of rubbing until the damage on the coating film surface was confirmed was measured.

2) Cellophane tape resistance: printed plywood
Based on the standard of color plywood standard (Japan Print Plywood / Color Plywood Industry Association), peeling (40 ° C. ± 3 ° C., after 2 hours) with Nichiban CelloTape (trademark) was performed, and the surface condition was observed. .

3) Abrasion resistance: According to the standard of JAS abrasion B test, a sandpaper is wound around a rubber abrasion wheel and a load of 5 is applied.
Abrasion test was conducted under the condition of 00g, and the printed pattern was 5
The case where 0% or more disappeared was judged as reject, and the case where it was 50% or less was judged as passed.

4) Contamination resistance: According to the criteria of JAS Contamination A test, a line of 10 mm width was formed on the coating film surface of the decorative board using oil-based ink, water-based ink and crayon, left for 4 hours, and then wiped off with methanol. The state of contamination was observed.

5) Water resistance: Coating film test pieces were immersed in water at room temperature for 3 days, and the degree of whitening of the film was evaluated by visual observation.

6) Acid resistance: After acetic acid (5% aqueous solution) was dropped onto the coating film, the film was covered with a watch glass, and after 6 hours, the surface condition was evaluated by visual observation.

7) Alkali resistance: Sodium carbonate (1% aqueous solution) was dropped on the coating film, covered with a watch glass, and after 6 hours, the surface condition was evaluated by visual observation.

The results of each characteristic test are shown in Table 1 below.

Example 2 A photopolymerization initiator (Darocur 1173, Irgacure 2959) was added to the active energy ray-curable water-based coating agent for the first protective layer and the second protective layer obtained in Example 1. However, the first and second protective layer coating films were formed on the water-based ink layer of the decorative paper substrate by the same method and conditions as in Example 1, and after thermal drying, an accelerating voltage of 20 was applied from the coating film side.
The coating film was cured by irradiating with an electron beam of 0 keV under the condition of an absorbed dose of 4 Mrad.

Then, as in Example 1, a hard coating film having an excellent surface gloss was obtained. Table 1 shows the evaluation results.

[Comparative Example 1] A decorative paper was prepared in the same manner as in Example 1 except that a solvent-free electron beam curable coating composition having the following composition was used. A decorative board was produced by performing the same electron beam. Table 1 shows the evaluation results.

6-functional urethane acrylate oligomer (Art Resin UN-3320HC, manufactured by Negami Kogyo Co., Ltd.) 50 parts EO modified bisphenol A diacrylate (BP-4EA, manufactured by Kyoeisha Chemical Co., Ltd.) 125 parts Tripropylene glycol diacrylate 120 parts Polyether modified Silicone (Kp-341: manufactured by Shin-Etsu Chemical Co., Ltd.) 3.5 parts

[0072]

[Table 1]

"Evaluation Result" As shown in Table 1,
It is confirmed that when the decorative paper according to each example is applied, the cellophane tape resistance and abrasion resistance are improved as compared with the case where the decorative paper according to the comparative example is applied.

[0074]

According to the surface-reinforced decorative paper according to the first aspect of the present invention, the first protective layer and the second protective layer are formed into an active energy ray-curable aqueous resin composition having excellent affinity with aqueous ink. As a result, the adhesive force between each protective layer and the water-based ink layer is improved, and the active energy ray-curable water-based resin composition is applied to the inside of the decorative paper base material in the heat drying process before curing the active energy ray. Since it permeates, it has an effect that it can be provided with hardness and wear resistance that can be used in furniture, housing equipment and the like.

In addition, since the above-mentioned first protective layer is composed of an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component, which is prepared so as not to have tackiness after thermal drying, after thermal drying The coating film of is low in redissolvability in water.

Therefore, it is possible to secure recoatability when a second protective layer is formed by applying an active energy ray-curable aqueous resin composition containing no aqueous emulsion resin in a subsequent step. Have.

Further, a filler such as an extender pigment is added at a high concentration in the first protective layer composed of an active energy ray-curable aqueous resin composition containing an aqueous emulsion resin as a main component to improve its abrasion resistance. On the other hand, the second protective layer composed of an active energy ray-curable aqueous resin composition containing no physical property of an aqueous emulsion resin is provided with its design property without adding a filler, thereby protecting the surface. It has an effect that it is possible to simultaneously satisfy the surface design and the high-level coating film physical properties, which were difficult to achieve with only one coating layer.

Next, according to the surface-reinforced decorative paper of the invention of claim 2, the active energy ray-curable aqueous resin composition has the above general formula (I) having an acryloyl group or a methacryloyl group at both ends. Since a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the following is contained, after the coating film of the active energy ray-curable aqueous resin composition for the first and second protective layers is formed,
By irradiating with active energy rays such as ultraviolet rays and electron rays, bifunctional or higher functional urethane acrylate or urethane methacrylate having an action as an emulsifier reacts with other polymerizable resin composition components to act as one component of a cross-linking agent. It is possible to form each protective layer with excellent balance of physical properties such as solvent resistance, water resistance, acid resistance, alkali resistance, and film strength, and unreacted components remain in the final protective layer coating film. It has a difficult effect.

According to the surface-reinforced decorative paper of the third aspect of the present invention, the dihydric alcohol residue of the bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the general formula (I) is ethylene oxide. The surface-reinforced decorative paper according to the invention of claim 4 is composed of a compound selected from ether-based polyols having a structure of propylene oxide and propylene oxide as a raw material, and is represented by the general formula (I). The composition ratio (molar ratio) of ethylene oxide and propylene oxide constituting the dihydric alcohol residue of the bifunctional or higher functional urethane acrylate or urethane methacrylate per repeating unit structure is 9: 1 to 4:
6, the hydrophilicity / hydrophobicity of the urethane acrylate or urethane methacrylate can be balanced, so that emulsifying ability for other resin composition components is imparted, whereby solvent resistance, water resistance,
It has the effect of being able to form an excellent protective layer due to the balance of physical properties such as acid resistance, alkali resistance, and film strength.

Next, according to the method of manufacturing a surface-reinforced decorative paper according to the inventions of claims 5 to 8, the surface-reinforced decorative paper according to claims 1 to 4 can be reliably manufactured, and at the same time a first protective layer is formed. The active energy ray-curable aqueous resin composition that forms the second protective layer uses water instead of a volatile vinyl monomer or an organic solvent as its diluting component, and ammonia, amine, etc. are generated during drying. Since there is no such problem, there is no problem in environmental hygiene, and further, since the active energy ray-curable aqueous resin composition is basically a one-pack type,
After use, it is possible to reuse the excess coating liquid, which is highly economical, and has the effect of significantly reducing equipment investment for preventing air pollution.

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Claims (8)

[Claims] 1. A surface-reinforced decorative paper for a decorative board, which is laminated on a decorative substrate, and a decorative paper substrate provided with a print pattern with an aqueous ink, and a decorative surface provided on the decorative paper substrate. A first protective layer composed of an active energy ray-curable aqueous resin composition whose main component is an aqueous emulsion resin prepared so as not to have tackiness after heat drying, and provided on the first protective layer, and A surface-reinforced decorative paper comprising a second protective layer composed of an active energy ray-curable aqueous resin composition that does not contain the aqueous emulsion resin. 2. One component of the active energy ray-curable aqueous resin composition is composed of a resin comprising an ultraviolet or electron beam-curable polymer, oligomer or monomer, and at least one component has the following general formula (I) 2. The surface-reinforced decorative paper according to claim 1, which contains a bifunctional or more urethane acrylate or urethane methacrylate represented by the formula (1). Embedded image R: hydrogen atom or methyl group X: isocyanate residue Y: dihydric alcohol residue 3. A compound in which the dihydric alcohol residue of bifunctional or higher-functional urethane acrylate or urethane methacrylate represented by the general formula (I) is selected from ether polyols having a structure of ethylene oxide and propylene oxide. 3. The surface-reinforced decorative paper according to claim 2, which is constituted as a raw material. 4. A composition ratio (molar ratio) of each of repeating units of ethylene oxide and propylene oxide constituting a dihydric alcohol residue of bifunctional or higher-functional urethane acrylate or urethane methacrylate represented by the general formula (I). 4) is set in the range of 9: 1 to 4: 6. 5. The method for producing a surface-reinforced decorative paper according to claim 1, wherein the printed surface of a decorative paper substrate provided with a print pattern of an aqueous ink is prepared so as not to have tackiness after heat drying. The active energy ray-curable aqueous resin composition containing the aqueous emulsion resin as a main component is applied to form a first protective layer, and the active energy ray-curable resin does not contain the aqueous emulsion resin on the first protective layer. The second protective layer is formed by coating the mold-type aqueous resin composition, and each protective layer is thermally dried, and then irradiated with ultraviolet rays or an electron beam to form the first protective layer and the second protective layer. A method for producing a surface-reinforced decorative paper, which comprises simultaneously curing. 6. One component of the active energy ray-curable aqueous resin composition is composed of a resin composed of an ultraviolet or electron beam-curable polymer, oligomer or monomer, and at least one component has the following general formula (I) 6. The method for producing a surface-reinforced decorative paper according to claim 5, which comprises a bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the formula (1). Embedded image R: hydrogen atom or methyl group X: isocyanate residue Y: dihydric alcohol residue 7. A compound in which the dihydric alcohol residue of bifunctional or higher-functional urethane acrylate or urethane methacrylate represented by the general formula (I) is selected from ether polyols having a structure of ethylene oxide and propylene oxide. The method for producing a surface-reinforced decorative paper according to claim 6, which is constituted as a raw material. 8. A composition ratio (molar ratio) of ethylene oxide and propylene oxide constituting each dihydric alcohol residue of bifunctional or higher functional urethane acrylate or urethane methacrylate represented by the general formula (I) per each repeating unit structure. ) Is set in the range of 9: 1 to 4: 6. The method for producing a surface-reinforced decorative paper according to claim 7, wherein