JP7639284B2 - Resin composition for decorative board, decorative sheet, and decorative board - Google Patents

Description

The present invention relates to a resin composition for decorative boards, a decorative sheet, and a decorative board. More specifically, the present invention relates to a resin composition for decorative boards, a decorative sheet using the resin composition for decorative boards, and a decorative board including the decorative sheet.

Conventionally, decorative boards have been used on the surfaces of tables, counters, walls, floors, etc., by laminating a resin-impregnated layer, such as impregnated paper obtained by impregnating a paper base material such as titanium paper with a thermosetting resin such as diallyl phthalate resin, on a base material, and then superimposing a mirror plate on the resin-impregnated layer and thermo-pressing to harden the thermosetting resin. The surface of the decorative board may be subjected to high gloss treatment, low gloss treatment (matte treatment), embossing, etc., for the purpose of imparting a sense of luxury or a desired pattern. In particular, decorative boards using diallyl phthalate resin are known as decorative boards that have weather resistance, a natural texture, heat resistance, chemical resistance, and dimensional stability.

By overlapping a substrate having an uneven surface on the surface of the decorative plate, an uneven surface is formed on the surface of the resin-impregnated layer, and embossing can be performed. If the resin-impregnated layer contains a color pigment, when embossing is performed, the convex parts of the resin-impregnated layer become dark in color and the concave parts become light in color, and a color intensity (harmonicity) according to the thickness of the resin-impregnated layer is expressed (see, for example, Patent Document 1).

In addition, from the perspective of disaster prevention, decorative boards are sometimes required to be flame retardant or non-combustible. To impart flame retardancy or non-combustibility to decorative boards, decorative boards are known in which a flame retardant such as aluminum hydroxide is blended into the resin-impregnated layer (see, for example, Patent Documents 2 to 4).

Japanese Patent Application Publication No. 5-147050 JP 2011-79870 A JP 2009-234200 A JP 2006-35839 A

However, if aluminum hydroxide is added to the resin-impregnated layer in an amount that provides sufficient non-flammability, there is a problem in that the mirror plate that is placed over the resin-impregnated layer will stick to the resin-impregnated layer during the thermo-compression molding process to form the decorative board, making it difficult to remove the mirror plate.

In addition, when aluminum hydroxide was added to a resin-impregnated layer containing a color pigment and embossed, the color depth (harmonicity) corresponding to the thickness of the resin-impregnated layer was not always achieved.

The object of the present invention is therefore to provide a resin composition for decorative panels that can be used to obtain a decorative panel that is non-flammable and that satisfies at least one of the following: excellent releasability from a mirror-finished panel after thermo-press molding, and excellent synchronization when embossed.

As a result of intensive research conducted by the present inventors to achieve the above object, it has been discovered that by using an unsaturated polyester resin having a number average molecular weight within a specific range in a resin composition for decorative boards containing a diallyl phthalate resin and an unsaturated polyester resin, and blending aluminum hydroxide having an average particle size within a specific range, it is possible to obtain a decorative board that is non-flammable and that satisfies at least one of the following: excellent releasability from a mirror plate after thermo-compression molding, and excellent synchronization when embossed. The present invention has been completed based on these findings.

That is, the present invention provides a resin composition for decorative panels that contains a diallyl phthalate resin, an unsaturated polyester resin, and aluminum hydroxide, the unsaturated polyester resin having a number average molecular weight of 500 to 2800, and the aluminum hydroxide having an average particle size of 3 μm or less.

The mass ratio of the diallyl phthalate resin to the unsaturated polyester resin (former:latter) is preferably 20:80 to 90:10.

The viscosity of the resin composition for decorative panels in an acetone solution with a solid content of 50% by mass at 20°C (rotation speed: 6 rpm) is preferably 100 to 800 mPa·s.

The resin composition for decorative panels may contain a color pigment.

The resin composition for decorative panels may contain magnesium hydroxide.

The content of aluminum hydroxide is preferably 5 to 90 parts by mass per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin.

The present invention also provides a decorative sheet comprising an impregnated base material and a resin-impregnated layer containing a thermosetting resin composition impregnated into the impregnated base material, the thermosetting resin composition being the resin composition for decorative panels according to any one of claims 1 to 6 or a cured product thereof.

The resin-impregnated layer preferably has the resin composition for decorative panels on the surface that will become the mirror plate side during thermo-compression molding.

The decorative sheet may have an embossed shape on the surface of the resin-impregnated layer.

The present invention provides a decorative board comprising a substrate and the decorative sheet provided on at least one surface of the substrate.

The resin-impregnated layer may have an embossed shape on the surface opposite the substrate.

The resin composition for decorative panels of the present invention makes it possible to obtain a decorative panel that is non-flammable and satisfies at least one of the following: excellent releasability from a mirror-finished panel after thermo-compression molding, and excellent synchronization when embossed.

1 is a cross-sectional view showing one embodiment of a decorative board using the decorative board resin composition of the present invention. FIG. 2 is a cross-sectional view showing another embodiment of a decorative board using the decorative board resin composition of the present invention. 3A to 3C are diagrams showing an embodiment of a method for manufacturing the decorative board shown in FIG. 2. 1A to 1C are diagrams showing an embodiment of a method for producing a decorative board having an embossed shape on the surface of a resin-impregnated layer.

[Resin composition for decorative panels]
The resin composition for decorative boards of the present invention contains at least a diallyl phthalate resin, an unsaturated polyester resin, and aluminum hydroxide.

The above-mentioned diallyl phthalate resin is a prepolymer having an allyl group in the molecule, and is a resin having thermosetting properties (thermosetting resin).

The diallyl phthalate resin contains at least a constituent unit derived from a diallyl phthalate monomer. Examples of the diallyl phthalate monomer include diallyl orthophthalate, diallyl isophthalate, and diallyl terephthalate. The diallyl phthalate monomer may be used alone or in combination of two or more. The diallyl phthalate resin may be used alone or in combination of two or more. The weight average molecular weight of the diallyl phthalate resin measured by GPC is preferably 10,000 to 50,000.

The unsaturated polyester resin may be liquid or solid at room temperature. Only one type of unsaturated polyester resin may be used, or two or more types may be used.

The unsaturated polyester resin may be a compound containing a structural unit derived from a polybasic unsaturated acid and a structural unit derived from a polyhydric alcohol. The unsaturated polyester resin may further contain a structural unit derived from a polybasic saturated acid. Only one type of the unsaturated acid, saturated acid, and polyhydric alcohol may be used, or two or more types may be used.

Examples of the polybasic unsaturated acids include maleic acid, fumaric acid, itaconic acid, and phthalic acid monomers (orthophthalic acid, isophthalic acid, and terephthalic acid). Of these, the unsaturated acids preferably contain phthalic acid monomers. It is also preferable that the unsaturated acids contain maleic acid.

Examples of the polyhydric alcohol component include ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, and hydrogenated bisphenol A. Of these, it is preferable that the polyhydric alcohol component contains propylene glycol. From the viewpoint of achieving superior releasability from the mirror plate, it is preferable that the polyhydric alcohol component contains ethylene glycol and/or hydrogenated bisphenol A.

In addition, air-curable unsaturated polyester resins may be used as the unsaturated polyester resin. For example, polyester resins containing structural units derived from aliphatic cyclic unsaturated acids such as tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophthalic acid, and methyl-3,6-endomethylenetetrahydrophthalic acid as the unsaturated acid, and structural units derived from allyl glycidyl ether as the polyhydric alcohol may be used.

The number average molecular weight (Mn) of the unsaturated polyester resin is 500 to 2800, preferably 800 to 2200. By having the number average molecular weight of 500 or more, the fluidity of the resin composition can be maintained, and the impregnation into the impregnated substrate is excellent. By having the number average molecular weight of 2800 or less, it is presumed that the number of bonds with the diallyl phthalate resin increases after thermal curing, and the releasability, clarity of image, and glossiness with respect to the mirror plate are good. In addition, the fluidity of the resin composition is high when a pressing plate having an uneven shape is superimposed on the resin impregnated layer, and the curing speed is relatively slow, which promotes the movement of the color pigment and provides excellent synchronization. The number average molecular weight is more preferably 800 to 1500 from the viewpoint of better releasability, clarity of image, and glossiness with respect to the mirror plate. In addition, the number average molecular weight is more preferably 1600 to 2200 from the viewpoint of better promoting the flow of the color pigment when embossing is performed and providing better synchronization. The above number average molecular weight is a value obtained by GPC measurement.

The weight average molecular weight (Mw) of the unsaturated polyester resin is not particularly limited, but is preferably 2500 to 7000, and more preferably 3500 to 5500. If the weight average molecular weight is 2500 or more, the fluidity of the resin composition can be maintained, and the impregnation into the impregnated substrate is superior. If the weight average molecular weight is 7000 or less, it is presumed that the number of bonds with the diallyl phthalate resin increases after thermal curing, and the releasability, clarity of image, and glossiness of the mirror plate are improved. In addition, the fluidity of the resin composition is high when a pressing plate having an uneven shape is superimposed on the resin-impregnated layer, and the curing speed is relatively slow, which promotes the movement of the color pigment and tends to improve synchronization. The weight average molecular weight is a value obtained by GPC measurement.

The molecular weight dispersity (Mw/Mn) of the unsaturated polyester resin is not particularly limited, but is preferably 1.5 to 4.5, and more preferably 2.0 to 4.0.

The acid value of the unsaturated polyester resin is not particularly limited, but is preferably 5 to 30 KOHmg/g, and more preferably 10 to 25 KOHmg/g.

The mass ratio of the diallyl phthalate resin to the unsaturated polyester resin in the resin composition for decorative boards (former:latter) is preferably 20:80 to 90:10, and more preferably 30:70 to 70:30. When the mass ratio is 30:70 or more, the decorative board tends to have better gloss, alkali resistance, and releasability from mirror-finished panels. From the viewpoint of better releasability from mirror-finished panels, sharpness, and gloss, the mass ratio is more preferably 51:49 to 70:30, and particularly preferably 52:48 to 60:40. Furthermore, from the viewpoint of even better non-flammability, the mass ratio is more preferably 30:70 to 40:60.

The total content of the diallyl phthalate resin and the unsaturated polyester resin in the resin composition for decorative boards is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and even more preferably 40 to 80% by mass, relative to the total amount (100% by mass) of the resin composition for decorative boards. If the content is 20% by mass or more, a resin-impregnated layer having sufficient strength can be obtained by hot-press molding.

The resin composition for decorative panels may contain a monomer constituting a diallyl phthalate resin or an unsaturated polyester resin, or an oligomer of the monomer (e.g., a polymer of 2 to 3 units). For example, it may contain the diallyl phthalate monomer, which is a constituent unit of the diallyl phthalate resin.

The resin composition for decorative boards contains aluminum hydroxide. By containing aluminum hydroxide, the decorative board has non-flammability. The shape of the aluminum hydroxide is not particularly limited, and examples include cylindrical, needle-like, and spherical shapes. Only one type of aluminum hydroxide may be used, or two or more types may be used.

The average particle diameter of the aluminum hydroxide in the resin composition for decorative board is 3 μm or less, preferably 2 μm or less, more preferably 1.5 μm or less. By having the average particle diameter of 3 μm or less, the flow of the resin composition during thermocompression molding is suppressed, the resin film thickness can be ensured to be sufficient, and the resin composition has excellent releasability from the mirror plate, high transparency, and excellent appearance. In addition, when a pressing plate having an uneven shape is superimposed on the resin impregnated layer, it is presumed that the movement of the coloring pigment is not hindered in the thin part of the resin composition, and the resin composition has excellent synchronization. Furthermore, the resin composition has excellent transparency. The average particle diameter is, for example, 0.2 μm or more, and may be 0.3 μm or more, or 0.5 μm or more. The average particle diameter can be measured by a laser diffraction/scattering particle size distribution measuring device, or can be measured from an electron microscope photograph, and can also be calculated from the electron microscope photograph using an image processing device. Usually, the average particle diameter is generally measured by a laser diffraction method.

The aluminum hydroxide may be surface-treated. By subjecting the aluminum hydroxide to a surface treatment, it becomes more dispersible in the resin composition for decorative boards. Examples of compounds for surface treatment include silane coupling agents and titanium coupling agents.

The silane coupling agent may be an organosilicon compound having two or three alkoxy groups in the molecule. Examples of the organosilicon compound include vinyl silanes such as vinyl triethoxy silane, vinyl trimethoxy silane, and vinyl tris (β-methoxyethoxy) silane; epoxy silanes such as β-(3,4-epoxycyclohexyl) ethyl trimethoxy silane and γ-glycidoxypropyl trimethoxy silane; amino silanes such as γ-aminopropyl triethoxy silane and N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxy silane; γ-mercaptopropyl trimethoxy silane; and γ-chloropropyl trimethoxy silane.

The content of aluminum hydroxide is preferably 5 to 90 parts by mass relative to 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin. When the content is 5 parts by mass or more, the non-combustibility and the image clarity are superior. From the viewpoint of obtaining better non-combustibility and image clarity while ensuring releasability from the mirror plate, the content is more preferably 20 to 80 parts by mass, and even more preferably 30 to 70 parts by mass. From the viewpoint of obtaining better synchronization when embossing is performed, the content is more preferably 7 to 50 parts by mass, and even more preferably 10 to 40 parts by mass.

The resin composition for decorative boards may contain a crosslinking agent for crosslinking the diallyl phthalate resin or the unsaturated polyester resin. The use of a crosslinking agent can improve the hardness of the resin-impregnated layer after heat curing, and improve the releasability, image clarity, and gloss. Examples of the crosslinking agent include polyfunctional compounds such as polyfunctional monomers having at least two polymerizable functional groups with unsaturated carbon-carbon double bonds, such as (meth)acryloyl groups or vinyl groups, and polymers of the polyfunctional monomers. Only one type of crosslinking agent may be used, or two or more types may be used.

Examples of the polyfunctional monomers include polyfunctional (meth)acrylates such as hexanediol di(meth)acrylate, dodecanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. Of the above polyfunctional compounds, poly(meth)acrylates of dipentaerythritol having three or more (meth)acryloyl groups in the molecule are preferred.

The content of the crosslinking agent is preferably 0.6 to 20 parts by mass, and more preferably 1 to 16 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin. When the content is within the above range, the hardness of the resin-impregnated layer after heat curing becomes more appropriate, and the releasability becomes more appropriate. In addition, the image clarity and glossiness are further improved, resulting in a better appearance.

The above-mentioned resin composition for decorative panels preferably contains a polymerization initiator (curing agent). By using the above-mentioned polymerization initiator, the curing speed becomes faster than the polymerization of diallyl phthalate resin or unsaturated polyester resin alone, and a resin-impregnated layer having a sufficient degree of curing can be obtained in a short time by hot-press molding. Examples of the above-mentioned polymerization initiator include organic peroxide-based curing agents such as benzoyl peroxide, tertiary butyl perbenzoate, methyl ethyl ketone peroxide, and dicumyl peroxide.

The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin.

The resin composition for decorative boards may contain other components in addition to the above-mentioned components. Examples of the other components include thermosetting resins other than diallyl phthalate resins and unsaturated polyester resins, flame retardants other than aluminum hydroxide, curing catalysts, curing accelerators, polymerization inhibitors, release agents, fillers such as silica, plasticizers, dispersants, thickeners, viscosity adjusters, colorants (pigments, dyes, etc.), defoamers, preservatives, UV absorbers, depleting agents, antibacterial agents, leveling agents, silane coupling agents, etc. Only one type of each of the above-mentioned other components may be used, or two or more types may be used.

When the resin composition for decorative boards is to have excellent synchronization when embossed, it is preferable that the resin composition for decorative boards contains a coloring pigment. As the coloring pigment, any known or conventional coloring pigment can be used, and among them, pearl pigments are preferable. The content of the coloring pigment is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin.

Other flame retardants besides the aluminum hydroxide include metal oxides such as magnesium hydroxide. When the resin composition for decorative boards is to have excellent synchronization when embossed, it is preferable to contain other flame retardants in addition to aluminum hydroxide in order to have excellent synchronization and sufficient non-flammability. On the other hand, when improving the releasability from the mirror plate or when molding stability is important, it is preferable not to contain magnesium hydroxide (for example, 5 parts by mass or less per 100 parts by mass of the diallyl phthalate resin and the unsaturated polyester resin). Only one type of the other flame retardants may be used, or two or more types may be used.

The average particle diameter of the other flame retardants is preferably 4 μm or less, more preferably 3 μm or less, and more preferably 2 μm or less, from the viewpoint of achieving better synchronization without inhibiting the movement of the color pigment in the thinner part of the resin composition when a pressing plate having an uneven shape is superimposed on the resin-impregnated layer. The average particle diameter is, for example, 0.2 μm or more, and may be 0.3 μm or more, or 0.5 μm or more. The average particle diameter of the other flame retardants is determined by the same method as the average particle diameter of aluminum hydroxide.

The content of the other flame retardants is appropriately set according to the content of all the flame retardants in the resin composition for decorative boards. The content of the flame retardant in the resin composition for decorative boards is preferably 10 to 90 parts by mass, more preferably 20 to 70 parts by mass, and even more preferably 30 to 60 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin.

When the above-mentioned release agent is contained, the releasability from the mirror plate is improved. Examples of the release agent include a fluorine-based release agent, a silicone-based release agent, and a wax-based release agent. Only one type of the above-mentioned release agent may be used, or two or more types may be used.

The content of the release agent is preferably 0.1 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin. If the content is 0.1 parts by mass or more, the release properties from the mirror plate will be better. If the content is 8 parts by mass or less, the adhesion between the resin-impregnated layer and the substrate in the decorative plate will be good.

When the polymerization inhibitor is included, the reaction rate of the diallyl phthalate resin and the unsaturated polyester resin can be adjusted, and molding stability can be improved. As the polymerization inhibitor, known or conventional ones can be used, for example, hydroquinones such as hydroquinone, methylhydroquinone, p-tert-butylcatechol, mono-tert-butylhydroquinone, etc.; phenols such as hydroquinone monomethyl ether, di-tert-butyl-p-cresol, etc.; quinones such as benzoquinone, p-benzoquinone, naphthoquinone, p-toluquinone, etc.; copper salts such as di-tert-butylhydroxytoluene, 2,6-di-tert-butyl-4-methylphenol, copper naphthenate, etc.; phenothiazine, etc. The polymerization inhibitors may be used alone or in combination.

The content of the polymerization inhibitor is preferably 0.005 to 0.5 parts by mass, more preferably 0.05 to 0.3 parts by mass, and even more preferably 0.8 to 0.15 parts by mass, per 100 parts by mass of the total of the diallyl phthalate resin and the unsaturated polyester resin. If the content is within the above range, the molding stability of the decorative board is superior.

The viscosity of the resin composition for decorative boards in an acetone solution with a solid content of 50% by mass at 20°C (rotation speed: 6 rpm) is preferably 110 to 800 mPa·s, more preferably 150 to 700 mPa·s. The viscosity of the resin composition for decorative boards in an acetone solution with a solid content of 50% by mass at 20°C (rotation speed: 60 rpm) is preferably 30 to 200 mPa·s, more preferably 40 to 120 mPa·s. The above viscosity is a value measured using a B-type viscometer for a solution obtained by adding acetone to the resin composition for decorative boards until the solid content concentration reaches 50% by mass.

The thixotropic index (TI) of the resin composition for decorative boards in a 50% solids solution in acetone at 20°C is preferably 3 to 8, more preferably 4 to 7. When the TI is 3 or more, the resin composition has high thixotropy and is more excellent in impregnation into the impregnated substrate. When the TI is 8 or less, the resin composition has appropriate fluidity when impregnated into the impregnated substrate, and is more excellent in impregnation into the impregnated substrate. The TI is a value calculated based on the viscosity of the 50% solids solution in acetone at 20°C, calculated as [viscosity (6 rpm)/viscosity (60 rpm)].

[Decorative sheet]
The resin composition for decorative boards can be used to produce decorative sheets and decorative boards. The decorative sheets include decorative sheets that have a resin-impregnated layer containing an impregnated base material and a thermosetting resin composition impregnated into the impregnated base material, and the thermosetting resin composition is the resin composition for decorative boards or a cured product thereof.

The decorative board resin composition is a thermosetting resin composition. The thermosetting resin composition includes both a resin composition having thermosetting properties (thermosetting resin composition) and a composition containing a resin obtained by curing a thermosetting resin in the thermosetting resin composition (such as a diallyl phthalate resin or an unsaturated polyester resin, which are prepolymers) (thermosetting resin composition). That is, the resin-impregnated layer includes a layer in which the thermosetting resin composition is impregnated into an impregnated substrate (a layer before thermosetting, a prepreg) and a layer in which the thermosetting resin in the composition is cured (a layer after thermosetting).

The resin-impregnated layer is a layer in which the resin composition for decorative boards or the cured product of the resin composition is impregnated into an impregnated substrate. The resin-impregnated layer may be a single layer or a multi-layer (laminate). The resin-impregnated layer may have a single layer of the resin composition for decorative boards, or may have layers of different resin compositions for decorative boards (multi-laminate). In particular, since the resin composition for decorative boards of the present invention has excellent releasability from mirror-finished boards, it is preferable that the resin-impregnated layer has the resin composition for decorative boards at least on the surface that will be the mirror-finished board side during thermo-compression molding.

The impregnated substrate is not particularly limited as long as it can be impregnated with the resin composition for decorative boards. Examples of the impregnated substrate include impregnated paper and cloth such as titanium paper, tissue paper, reinforced paper, kraft paper, and cellulose paper; and woven or nonwoven fabrics such as polyester, rayon, acrylic, and vinylon. The impregnated paper and cloth may be printed. The impregnated substrate may be single-layered or multi-layered.

The amount of the thermosetting resin composition impregnated into the impregnated substrate is preferably 10 to 500 g/ ^m2 , more preferably 100 to 300 g/ ^m2 , per area of the impregnated substrate. If the amount is 10 g/ ^m2 or more, the amount of impregnation is sufficient and the releasability from the mirror plate is excellent. If the amount of impregnation is 500 g/m2 or ^less , the cost can be reduced.

The thickness of the resin-impregnated layer is not particularly limited, but is, for example, 10 to 200 μm, and preferably 20 to 100 μm. If the thickness is 10 μm or more, the occurrence of defects such as poor flow during thermo-compression molding can be suppressed. If the thickness is 200 μm or less, warping of the molded product due to resin shrinkage can be suppressed.

The resin-impregnated layer can be produced by a known or conventional method, for example, as follows. First, a resin composition for decorative boards, which is a thermosetting composition, is prepared. The resin composition for decorative boards is obtained by mixing a diallyl phthalate resin, an unsaturated polyester resin, and aluminum hydroxide with the various components described above as necessary. When the resin composition for decorative boards is low in viscosity, the impregnated substrate can be immersed in a bath of the resin composition for decorative boards to be impregnated. When the resin composition for decorative boards is a high-viscosity liquid or solid, the resin composition for decorative boards is diluted or dissolved in an appropriate solvent, such as an organic solvent such as acetone, toluene, or methyl ethyl ketone, to obtain a resin liquid of appropriate viscosity, and the impregnated substrate is immersed in the resin liquid, and then dried to volatilize the solvent. The impregnation temperature is, for example, 10 to 35°C, preferably 20 to 30°C. Although the method of immersing the impregnated substrate in the bath of the resin composition for decorative boards has been described, the impregnation may also be performed by applying the resin composition for decorative boards to the surface of the impregnated substrate and leaving it to soak in. When the thermosetting resin composition is a cured product of the resin composition for decorative boards, the resin composition for decorative boards can be cured and produced by hot pressing using the method described in detail later in the method for producing decorative boards.

[Decorative board]
The decorative sheet can be used to produce a decorative board. The decorative board includes, for example, a substrate and the decorative sheet provided on one side of the substrate. More specifically, the decorative board includes at least a laminated structure of a substrate and a decorative sheet including a resin-impregnated layer in which the resin composition for decorative board is impregnated into the substrate.

In the decorative board, the surface of the resin-impregnated layer (i.e., the surface opposite the substrate) may have an embossed shape. A decorative board having a resin-impregnated layer made using the resin composition for decorative boards of the present invention exhibits a synchronization according to the thickness of the resin-impregnated layer when embossed.

The decorative plate may have other layers in addition to the above-mentioned layers. Examples of the other layers include a primer layer for improving adhesion between the resin-impregnated layer and the substrate, a core layer for imparting shape stability to the decorative plate, and a protective film for protecting the surface of the resin-impregnated layer. It is preferable that the surface of the resin-impregnated layer, which is the side on which the mirror plate is superimposed during thermocompression molding, does not have a release layer.

1 and 2 show one embodiment of the decorative board. The decorative board 10 shown in FIG. 1 comprises a substrate 1, a resin-impregnated layer 2, and a protective film 3. The resin-impregnated layer 2 is a layer (prepreg) in which the resin composition for decorative boards, which is a thermosetting resin composition, is impregnated into the impregnated substrate before heat curing, and is formed on one surface of the substrate 1. The protective film 3 is formed on the surface of the resin-impregnated layer 2 opposite the substrate 1. The decorative board 10' shown in FIG. 2 comprises a substrate 1, a resin-impregnated layer 2', and a protective film 3. The resin-impregnated layer 2' is a layer in which the resin composition for decorative boards is impregnated into the impregnated substrate, and is obtained by thermally curing the resin-impregnated layer 2.

Examples of the substrate include known or conventional substrates used in decorative boards. Examples of the substrate include organic substrates and inorganic substrates. Examples of the organic substrate include wood substrates such as veneer, plywood, laminated lumber, particle board, medium density fiberboard (MDF), high moisture fiberboard, and kenaf board; fibrous substrates such as paperboard, woven fabric, nonwoven fabric, resin-impregnated paper, and resin-impregnated cloth; and synthetic resin substrates such as acrylic resin board, styrene resin board, ABS resin board, polycarbonate resin board, nylon resin board, polystyrene resin board, polypropylene resin board, polyester resin board, and glass fiber reinforced plastic board. Examples of the inorganic substrate include metal substrates such as aluminum plates, stainless steel plates, duralumin plates, steel plates, and brass plates; inorganic substrates such as magnesium oxide plates, aluminum hydroxide plates, aluminum oxide plates, silicon oxide plates, titanium oxide plates, magnesium chloride plates, calcium silicate plates, volcanic glassy material plates, gypsum (calcium sulfate) plates, slag gypsum plates, limestone (calcium carbonate) plates, wood wool cement plates, slag cement plates, lightweight aerated concrete plates, and glass fiber reinforced concrete plates. The substrate may be a single layer or a laminate of the same or different layers. The substrate may also be subjected to an easy-adhesion treatment such as a sealer treatment or a primer treatment to improve adhesion to the resin-impregnated layer.

The thickness of the substrate is not particularly limited, but is, for example, 2 to 50 mm, and preferably 3 to 30 mm. If the thickness is 2 mm or more, it has sufficient strength and is less likely to break. If the thickness is 50 mm or less, it is lightweight and easy to handle.

The protective film may be any known or conventional film used for decorative panels, such as a plastic film that has been subjected to a release treatment, such as a polyethylene terephthalate film (PET film), a polypropylene film, or a polybutylene terephthalate film, or a low-adhesion film. The protective film is peeled off when the decorative panel is used.

The Gd value of the surface of the resin-impregnated layer (the surface opposite the substrate) is not particularly limited, but is preferably 0.2 or more, and more preferably 0.3 or more. If the Gd value is 0.2 or more, the decorative sheet has better image clarity.

The 20° gloss value (JIS Z8741) of the surface of the resin-impregnated layer (the surface opposite the substrate) is not particularly limited, but is preferably 50 or more, more preferably 60 or more, and even more preferably 70 or more. If the gloss value is 50 or more, the gloss of the decorative sheet is superior.

[Method of manufacturing decorative panels]
An embodiment of the manufacturing method of the decorative board is described with reference to FIG. 3. First, as described above, the thermosetting resin composition for decorative boards, which is prepared by diluting or dissolving with a solvent as necessary, is impregnated into an impregnated substrate, and then dried as necessary to volatilize the solvent, to prepare a resin-impregnated layer 2 in which the thermosetting resin composition for decorative boards is impregnated into the impregnated substrate. Next, as necessary, the resin-impregnated layer 2 and a releasable substrate such as a polyethylene film are laminated together to obtain a decorative sheet. The lamination can be performed, for example, by laminating using a pressure roll.

Next, the decorative sheet is placed on the substrate 1 with the resin-impregnated layer 2 facing the substrate 1, and if a releasable substrate is present, the releasable substrate is peeled off, and the mirror plate 4 is superimposed on the resin-impregnated layer 2 to obtain a laminate in which the decorative sheet 10 and the mirror plate 4 are laminated. The surface of the mirror plate 4 facing the resin-impregnated layer 2 has a shape for transferring a design to the resin-impregnated layer as necessary.

Next, a press is used to apply heat and pressure from above and below the laminate including the decorative plate 10 to perform thermocompression molding, hardening the resin-impregnated layer 2 to form a thermo-cured resin-impregnated layer 2', and obtaining a laminate in which the decorative plate 10' and the mirror plate 4 are laminated. As described above, the thermocompression molding method is preferably a laminate thermocompression molding method, in which the resin-impregnated layer 2 and the substrate 1 are overlapped and placed in a mold, and then heated, pressurized, and cured. The thermocompression molding can be preferably performed under conditions of, for example, a pressure of 10 to 25 kgf/cm ² , a temperature of 120 to 190° C., and a time of 30 seconds to 15 minutes.

The laminate obtained after thermocompression molding includes a decorative board 10' in which a substrate 1 and a thermoset resin-impregnated layer 2' provided on the substrate 1 are laminated. The mirror plate 4 is then removed to obtain the decorative board 10'. In the decorative board, the resin-impregnated layer formed from the resin composition for decorative board has excellent releasability from the mirror plate, so that the mirror plate 4 can be easily removed.

When preparing a decorative board 10' having an embossed shape on the surface of the resin-impregnated layer 2', a pressing plate 5 having an uneven shape on the surface facing the resin-impregnated layer 2 is used instead of the mirror plate 4. Then, as shown in FIG. 4, when the pressing plate 5 is superimposed on the resin-impregnated layer 2, an uneven shape corresponding to the uneven shape is formed on the surface of the resin-impregnated layer 2. That is, the resin-impregnated layer 2 has a thick film portion 2a and a thin film portion 2b. When an uneven shape is formed on the surface of the resin-impregnated layer 2, a high pressure is applied to the area that becomes the thin film portion 2b relative to the area that becomes the thick film portion 2a. When the resin-impregnated layer 2 contains a color pigment, the color pigment flows from the area that becomes the thin film portion 2b to the area that becomes the thick film portion 2a when pressure is applied. At this time, the flow of the color pigment is not hindered and can flow smoothly due to the small average particle diameter of the aluminum hydroxide. As a result, in the resin-impregnated layer 2', the amount of color pigment per unit area in the thick film portion 2a is greater than the amount in the thin film portion 2b, and synchronization is obtained. It is then subjected to thermo-compression molding using a press, resulting in a decorative board 10' with an embossed shape on the surface of the resin-impregnated layer 2'.

A protective film such as a PET film may then be attached to the surface of the resin-impregnated layer 2' of the decorative board 10'. In this manner, the above-mentioned decorative board can be manufactured.

As described above, the decorative board having a resin-impregnated layer obtained using the resin composition for decorative boards of the present invention has excellent non-flammability and excellent release properties from the mirror plate after thermo-press molding because it contains aluminum hydroxide having an average particle size within a specific range. Therefore, there is no need to provide a separate release layer between the resin-impregnated layer and the mirror plate during thermo-press molding. And, because the average particle size of the aluminum hydroxide is within a specific range, the flow of the resin composition during thermo-press molding is suppressed, and a sufficient resin film thickness can be ensured, and the obtained decorative board has excellent clarity and gloss, high transparency, and excellent appearance. In addition, when a resin-impregnated layer is prepared by blending a coloring pigment into the resin composition for decorative boards and the surface of the resin-impregnated layer is embossed, synchronization according to the thickness of the resin-impregnated layer is expressed.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

<Decorative board with excellent release properties>
Example 1
Diallyl orthophthalate prepolymer (methyl ethyl ketone 50% by mass solution viscosity (30 ° C) 96.5 mPa · s, manufactured by Osaka Soda Co., Ltd.) 56 parts by mass, unsaturated polyester (product name "TH-2510", number average molecular weight 1291, weight average molecular weight 4404, molecular weight dispersity 3.41, acid value 12.8 KOH mg / g, manufactured by DIC Material Co., Ltd.) 43 parts by mass, dipentaerythritol hexaacrylate 14 parts by mass, aluminum hydroxide (product name "BF013STM", average particle size 1 μm, surface treated, manufactured by Nippon Light Metal Co., Ltd.) 50 parts by mass, benzoyl peroxide 4 parts by mass, internal release agent (product name "Zelec UN", manufactured by DuPont) 3 parts by mass, hydroquinone (polymerization inhibitor) 0.2 parts by mass, and defoamer 0.1 parts by mass were dissolved in 100 parts by mass of acetone to prepare a resin composition solution. A 60 g/ ^m2 printed pattern paper was immersed in the resin composition solution at 25°C to impregnate it with the resin composition, and then heated in a 105°C hot air circulating oven for 90 seconds to volatilize the solvent, thereby obtaining a decorative sheet consisting of 160 g/ ^m2 impregnated paper (impregnation amount per 100 parts by mass of printed pattern paper: 167 parts by mass).

A substrate (product name "Dailite", manufactured by Daiken Kogyo Co., Ltd., thickness 3 mm, non-combustible material) was placed on the circumferential plate, and the decorative sheet was placed on the substrate so that the impregnated paper was in contact with the substrate. Then, using a press machine, pressure was applied so that the hot plate on which the mirror plate was set was the impregnated paper side and the other hot plate was the circumferential plate side, and heat was applied to perform thermo-compression molding. The thermo-compression molding was performed at a temperature of 160°C and a pressure of 16 kgf/ ^cm2 for 1 minute. After that, the pressure was released, and the laminate of the circumferential plate, substrate, and decorative sheet was removed from the press machine and cooled to room temperature to obtain a decorative plate.

Example 2
A decorative sheet and a decorative board were produced in the same manner as in Example 1, except that the amount of hydroquinone was changed to 0.1 parts by mass.

Comparative Example 1
A decorative sheet and a decorative board were produced in the same manner as in Example 1, except that 60 parts by mass of aluminum hydroxide (product name "BE043STM", average particle size 4 μm, surface-treated, manufactured by Nippon Light Metal Co., Ltd.) was used.

(evaluation)
The decorative boards obtained in Examples 1 and 2 and Comparative Example 1 were evaluated as follows. The evaluation results are shown in Table 1.

(1) Demoldability When producing each decorative panel obtained in the Examples and Comparative Examples, the demoldability was judged according to the following criteria based on the time it took for the molded product to fall from the mirror plate when the pressure was released after the molding time had elapsed.
[Judgment criteria]
○ (Good): Peels off from the mirror plate when pressure is released, or falls off from the mirror plate shortly thereafter.
× (bad): It takes a long time for the mirror to fall off the plate.

(2) Molding Stability The surface of the resin-impregnated layer of each of the decorative boards obtained in the Examples and Comparative Examples was visually observed and rated according to the following criteria.
[Judgment criteria]
◯ (Good): No flow problems such as pinholes occurred.
△ (usable): slight flow problems such as pinholes have occurred.
× (bad): A large amount of flow defects such as pinholes were observed.

(3) 20° Gloss The surface of the resin-impregnated layer of each of the decorative panels obtained in the Examples and Comparative Examples was measured using a gloss meter (product name "micro-TRI-gloss", manufactured by Gardner) according to the method specified in JIS Z8741.

(4) Gd value The resin-impregnated layer surface of each of the decorative panels obtained in the examples and comparative examples was measured for its distinctness measurement value (Gd value) using a portable clarity and gloss meter (product name "PGD-4", PGD meter, Japan Color Research Institute, manufactured by Tokyo Koden Co., Ltd.).

As shown in Table 1, the decorative panels obtained in Examples 1 and 2 were evaluated as having excellent release properties. Furthermore, due to the inclusion of a sufficient amount of aluminum hydroxide, they were evaluated as being non-flammable, having excellent molding stability, a high 20° gloss and excellent luster, a high Gd value and excellent image clarity, and having a good appearance. On the other hand, when the average particle size of the aluminum hydroxide was 4 μm (Comparative Example 1), the panels were evaluated as having poor release properties.

<Decorative plate having embossed shape>
Example 3
Diallyl orthophthalate prepolymer (viscosity of 50% by mass solution in methyl ethyl ketone (30°C) 96.5 mPa·s, manufactured by Osaka Soda Co., Ltd.) 38 parts by mass, unsaturated polyester (product name "DH-2000B", number average molecular weight 1869, weight average molecular weight 4846, molecular weight dispersity 2.59, acid value 21.1 KOHmg/g, manufactured by DIC Material Co., Ltd.) 81 parts by mass, dipentaerythritol hexaacrylate 5 parts by mass, aluminum hydroxide (product name "BF013STM", average particle size 1 μm, surface-treated, manufactured by Nippon Light Metal Co., Ltd.) A resin composition solution was prepared by dissolving 37.5 parts by mass of magnesium hydroxide (trade name "Magseeds N-6", average particle size 1.3 μm), 12.5 parts by mass of magnesium hydroxide (trade name "Magseeds N-6", average particle size 1.3 μm), 3 parts by mass of benzoyl peroxide, 1 part by mass of an internal release agent (trade name "Zelec UN", manufactured by DuPont), 0.05 part by mass of hydroquinone (polymerization inhibitor), 3 parts by mass of finely powdered silica (trade name "Carplex", manufactured by Shionogi & Co., Ltd.), 3 parts by mass of pearl pigment (trade name "Iriodin 520", manufactured by Merck), and 0.15 parts by mass of an antifoaming agent in 100 parts by mass of acetone. A 60 g/ ^m2 dark color printed pattern paper as an impregnation substrate was immersed in the above resin composition solution at 25°C to impregnate the paper with the resin composition, and then heated in a 105°C hot air circulating oven for 90 seconds to volatilize the solvent, thereby obtaining a decorative sheet made of 160 g/ ^m2 impregnated paper (impregnation amount per 100 parts by mass of printed pattern paper: 167 parts by mass).

A substrate (product name "Dailite", manufactured by Daiken Kogyo Co., Ltd., thickness 3 mm, non-combustible material) was placed on the circulating plate, and the decorative sheet was placed on the substrate so that the impregnated paper was in contact with the substrate. Then, using a press machine, pressure was applied so that the hot plate with the pressure plate set was the impregnated paper side and the other hot plate was the circulating plate side, and heat was applied to perform thermo-compression molding. The surface of the press plate facing the impregnated paper was formed with an uneven shape for imparting an embossed shape. The thermo-compression molding was performed at a temperature of 150°C and a pressure ^of 16 kgf/cm2 for 3 minutes. After that, the pressure was released, and the laminate of the circulating plate, substrate, and decorative sheet was removed from the press machine and cooled to room temperature to obtain a decorative plate.

Example 4
A decorative sheet and a decorative board were produced in the same manner as in Example 3, except that 80 g/m ² white paper was used as the impregnated substrate.

Example 5
A decorative sheet and a decorative board were produced in the same manner as in Example 3, except that aluminum hydroxide used was "BF013" (average particle size 1 μm, no surface treatment, manufactured by Nippon Light Metal Co., Ltd.).

Example 6
A decorative sheet and a decorative board were produced in the same manner as in Example 5, except that 80 g/m ² white paper was used as the impregnated substrate.

Comparative Example 2
A decorative sheet and a decorative board were produced in the same manner as in Example 3, except that the aluminum hydroxide used was "BE043STM" (average particle size 4 μm, surface-treated, manufactured by Nippon Light Metal Co., Ltd.).

Comparative Example 3
A decorative sheet and a decorative board were produced in the same manner as in Comparative Example 2, except that 80 g/m ² white paper was used as the impregnated substrate.

(evaluation)
The decorative boards obtained in Examples 3 to 6 and Comparative Examples 2 and 3 were evaluated as follows. The evaluation results are shown in Table 2.

(5) Synchronization The surface of the resin-impregnated layer of each of the decorative boards obtained in the Examples and Comparative Examples was visually observed and rated according to the following criteria.
[Judgment criteria]
◯ (Good): The difference in color intensity between the recessed and protruding parts is large, and the color is clearly in harmony with the embossed shape.
× (bad): The difference in color intensity between the recessed and protruding parts is small, and no harmony with the embossed shape is felt.

As shown in Table 2, the decorative panels obtained in Examples 3 to 6 were evaluated as having excellent synchronization. On the other hand, when the average particle size of the aluminum hydroxide was 4 μm (Comparative Examples 2 to 3), the synchronization was evaluated as being poor.

Example 7
A decorative sheet and a decorative board were produced in the same manner as in Example 3, except that the amount of impregnation was 183 parts by weight per 100 parts by weight of the printed pattern paper.

(6) Combustion Test A combustion test was conducted for each of the decorative boards obtained in Examples 3 and 7 in accordance with ISO 5660 "Cone Calorimeter Method". The combustion test was conducted twice for each decorative board. As a result, the average value of the total heat generation amount for 20 minutes after the start of heating, obtained from the two combustion tests, was 6.5 MJ/ ^m2 for Example 3 and 7.5 MJ/ ^m2 for Example 7. It should be noted that a total heat generation amount of 8 MJ/ ^m2 or less indicates excellent non-combustibility. From these results, it is recognized that the decorative boards of Examples 4 to 6, which have the same impregnation amount, also have non-combustibility.

The physical properties of the unsaturated polyester resins used in the examples and comparative examples and the viscosity of a 50% by mass solids acetone solution of each resulting resin composition were evaluated as follows:

(7) Average Molecular Weight of Unsaturated Polyester Resin The weight average molecular weight and number average molecular weight were measured by GPC using a standard polystyrene calibration curve under the following conditions.
Equipment: Shimadzu Corporation Prominence-i, LC-2030
Column: Shodex LF-804 x 2, guard column S
Transfer phase: THF
Flow rate: 1.0ml/min
Injection volume: 50 μl
Column temperature: 40°C

(8) Viscosity Acetone was added to the resin composition so that the solid content concentration was 50% by mass, and the viscosity of the resulting solution was measured at 20° C. using a B-type viscometer (product name "BM type viscometer", manufactured by Tokimec Co., Ltd.) with a rotor No. 1 at rotation speeds of 6 rpm and 60 rpm. The rotor was rotated for at least 30 seconds, and the value when the value stabilized was read and used as the viscosity.

1 Base material 2 Resin-impregnated layer (before heat curing, prepreg)
2a thick film portion 2b thin film portion 2' resin impregnated layer (heat cured)
3 Protective film 4 Mirror plate 5 Pressing plate 10, 10' Decorative plate

Claims (9)

A resin composition for decorative boards, comprising a diallyl phthalate-based resin, an unsaturated polyester-based resin, aluminum hydroxide, and a release agent;
The unsaturated polyester resin has a number average molecular weight of 500 to 2800.
The average particle size of the aluminum hydroxide is 0.2 μm to 3 μm.
a mass ratio (the former:the latter) of the diallyl phthalate-based resin to the unsaturated polyester-based resin is 20:80 to 90:10;
the content of the aluminum hydroxide is 30 to 70 parts by mass per 100 parts by mass of the diallyl phthalate resin and the unsaturated polyester resin in total ,
The resin composition for decorative boards is used for producing a decorative sheet,
The decorative sheet includes a resin-impregnated layer including an impregnated base material and a thermosetting resin composition impregnated into the impregnated base material, the thermosetting resin composition being the resin composition for decorative panels or a cured product thereof;
The resin-impregnated layer has the resin composition for decorative panels on a surface that will become a mirror plate side during thermo-compression molding . The resin composition for decorative boards according to claim 1, wherein the viscosity of a 50% by mass solids solution of the resin composition for decorative boards in acetone at 20°C (rotation speed: 6 rpm) is 100 to 800 mPa·s. The resin composition for decorative panels according to claim 1 or 2, which contains a color pigment. The resin composition for decorative panels according to any one of claims 1 to 3, which contains magnesium hydroxide. The present invention provides a resin-impregnated layer comprising an impregnated base material and a thermosetting resin composition impregnated into the impregnated base material,
The decorative sheet, wherein the thermosetting resin composition is the resin composition for decorative panels according to any one of claims 1 to 4 or a cured product thereof. A decorative sheet comprising an impregnated base material and a resin-impregnated layer comprising a thermosetting resin composition impregnated in the impregnated base material,
The thermosetting resin composition is a resin composition for decorative boards or a cured product thereof,
The resin composition for decorative boards contains a diallyl phthalate-based resin, an unsaturated polyester-based resin, aluminum hydroxide, and a release agent,
The unsaturated polyester resin has a number average molecular weight of 500 to 2800.
The average particle size of the aluminum hydroxide is 0.2 μm to 3 μm.
a mass ratio (the former:the latter) of the diallyl phthalate-based resin to the unsaturated polyester-based resin is 20:80 to 90:10;
the content of the aluminum hydroxide is 30 to 70 parts by mass per 100 parts by mass of the diallyl phthalate resin and the unsaturated polyester resin in total,
The resin-impregnated layer is a decorative sheet having the resin composition for decorative panels on a surface that will become a mirror plate during thermo-compression molding. The decorative sheet according to claim 5 or 6, wherein the surface of the resin-impregnated layer has an embossed shape. A decorative board comprising a substrate and a decorative sheet according to any one of claims 5 to 7 provided on at least one surface of the substrate. The decorative board according to claim 8, wherein the resin-impregnated layer has an embossed shape on the surface opposite the substrate.

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