JP2002000356A - Top plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative top plate which is light in weight, has sufficient strength, excellent surface hardness and anti-staining, and can easily be recycled. SOLUTION: A hollow plate is formed by metal plates, and a foamed plastic is filled in the hollow plate, which contributes to its lightness and strength. The hollow plate is made of a front plate 2 with connecting parts 2a at its both sides and a back plate 3 with connecting parts 3a at its both sides, and the openings at the both ends are closed by lid plates 4. A sheet with a protective layer for surface which is made of a cured product of an ionizing radiation curable resin, is attached to the surface of the metal plates. The decorative sheet would be neither broken nor cracked and has excellent of surface hardness and anti-staining, and the environmental pollution will be reduced when the top plate is disposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a top plate used for desks, tables, counters and the like.

[0002]

2. Description of the Related Art Conventionally, as described above, wooden top plates for desks, tables, counters and the like have generally been widely used. Steel plate is used. A simple one is a top plate made of painted steel plate. Also, a so-called melamine obtained by impregnating a thermosetting resin such as a melamine resin on a titanium paper on which a wood grain, a stone grain, a cloth grain, or a variety of abstract patterns are printed, drying, and then heating and pressing to cure. A top plate formed by attaching a decorative plate to a substrate such as a steel plate via an adhesive is also used.

[0003]

Among the above-mentioned ones, the former steel plate made of steel plate becomes heavy if it is intended to provide sufficient strength. In addition, the latter decorative steel sheet
Although it shows good performance in terms of processability such as surface hardness and stain resistance, the titanium paper used for melamine decorative board is expensive, and of course, the top plate using melamine decorative board is also expensive. It has to be expensive. In addition, a top plate formed by sticking a melamine decorative plate to a substrate such as a steel plate has a problem that it is difficult to separate the melamine decorative paper from the steel plate, and cannot be separated and recycled at the time of disposal.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide melamine having sufficient strength while reducing the weight, and in terms of surface hardness, stain resistance and the like. It is an object of the present invention to provide a top plate that has the same performance as a top plate using decorative paper and that can be recycled.

[0005]

The top plate according to the first aspect of the present invention is configured such that a hollow plate is formed of a metal plate, and the hollow plate is filled with foamed plastic. Features.

In the top plate according to the second aspect of the present invention, in the top plate according to the first aspect, the hollow plate-like body is formed such that the hollow plate-shaped body has a fitting portion formed on both sides, and the hollow plate-like body is fitted on both sides. And a back plate formed with a fitting portion fitted with the portion, and openings at both ends thereof are closed by a lid plate.

A top plate according to a third aspect of the present invention is the top plate according to the first or second aspect, wherein a reinforcing material is provided in the hollow plate-like body.

A top plate according to a fourth aspect of the present invention is the top plate according to any one of the first to third aspects, wherein the surface protective layer comprises a cross-linked cured product of an ionizing radiation-curable resin on the surface of the metal plate. Characterized in that a decorative sheet formed with the above is adhered.

[0009]

FIG. 1 is a perspective view showing an example of a top plate according to the present invention, and FIG. 2 is a perspective view showing a part of a part cut along XX of FIG. As shown in these figures, the top plate 1 has a hollow plate-like body formed by the front plate 2 and the back plate 3, and the opening at both ends thereof is closed by the lid 4, and the foamed plastic 5 is placed inside the top plate 1. Is filled.

The front plate 2 is formed by forming bent portions 2a on both sides of a metal plate on which a decorative sheet is adhered, and the back plate 3 is formed on both sides of a metal plate on which a decorative sheet is not adhered. Formed on the side is a fitting portion 3a that fits with the fitting portion 2a of the front plate. As shown in FIG. 2, these fitting portions 2a, 3a mesh with each other to form a hollow plate-like body. ing.

Further, in the top plate of this embodiment, as shown in FIG. 2, a reinforcing member 6 is provided in a hollow plate-like body. Although the illustrated reinforcing member 6 is a U-shaped cross-section plate member and extends in the length direction, the cross-sectional shape of the reinforcing member is not limited to this. Such a reinforcing material is provided to improve the strength of the hollow plate-shaped body, but may not be provided if there is no problem in the strength of the foamed plastic 5 alone depending on the use.

As the metal plate constituting the front plate and the back plate of the top plate of the present invention, iron, carbon steel, stainless steel, aluminum, copper, duralumin and the like are used. These may be plated with zinc, tin, chromium, etc., or coated with resin, if necessary. It is preferable to use a metal having good thermal conductivity as the metal plate in consideration of a case where a cigarette fire, a hot pot or the like is accidentally put on.

The front plate 2 has a decorative sheet 20 adhered to a metal plate 10 as shown in FIG. As the decorative sheet 20, it is preferable to use a sheet in which a surface protective layer 22 made of a crosslinked and cured product of an ionizing radiation-curable resin is formed on a base sheet 21. As the base sheet, a thermoplastic resin or paper is used. The materials are listed below.

As the polyolefin-based thermoplastic resin,
Polyethylene (low or high density), polypropylene,
Polymethylpentene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, high crystalline non-elastomeric polyolefin resin such as ionomer,
Alternatively, various olefin-based thermoplastic elastomers are used. As olefinic thermoplastic elastomers,
For example, the following can be used.

In Japanese Patent Publication No. Hei 6-23278,
(A) As a soft segment, the number average molecular weight Mn is 2
An atactic polypropylene soluble in boiling heptane having a ratio Mw / Mn ≦ 7 of 5,000 or more and a weight average molecular weight Mw and a number average molecular weight Mn of 10 to 90% by weight;
(B) Soft polypropylene comprising a mixture of 90 to 10% by weight of a heptane-insoluble isotactic polypropylene having a melt index of 0.1 to 4 g / 10 min as a hard segment. Among this kind of olefin-based thermoplastic elastomer, uneven elongation during molding,
It is hard to cause so-called "necking", and it is suitable for molding and embossing using heat and pressure as a mixture having a mixture of isotactic polypropylene and atactic polypropylene. The weight ratio of tic polypropylene is 5% by weight or more and 50% by weight or less.

A thermoplastic elastomer comprising an ethylene / propylene / butene copolymer resin. Here, as the butene, any one of the three structural isomers of 1-butene, 2-butene and isobutylene can be used. The copolymer is a random copolymer and partially includes an amorphous portion. Preferred specific examples of the ethylene / propylene / butene copolymer include the following. (1) Those described in JP-A-9-1111055. This is a random copolymer of a terpolymer of ethylene, propylene and butene. The weight ratio of the monomer components is 90% by weight or more of propylene. The melt flow rate is preferably 1 to 50 g / 10 minutes at 230 ° C. and 2.16 kg. Then, based on 100 parts by weight of such a tertiary random copolymer, 0.01 to 50 parts by weight of a transparent nucleating agent containing an aryl phosphate ester compound as a main component,
It is obtained by melting and kneading 0.003 to 0.3 parts by weight of a fatty acid amide having 12 to 22 carbon atoms. (2) Those described in JP-A-5-77371. This is a terpolymer of ethylene, propylene, and 1-butene. The content of the propylene component is 50 to 100% by weight of the amorphous polymer 20 to 100% by weight, and the crystalline polypropylene is 80 to 0% by weight. It is added. (3) Those described in JP-A-7-316358. This is a terpolymer of ethylene, propylene, and 1-butene, and is isotactic with respect to 20 to 100% by weight of a low crystalline polymer having a propylene and / or 1-butene content of 50% by weight or more. An oil gelling agent such as N-acylamino acid amine salt or N-acylamino acid ester is added in an amount of 0.5% by weight to 100 parts by weight of a composition in which 80 to 0% by weight of a crystalline polyolefin such as polypropylene is mixed. is there.

The ethylene / propylene / butene copolymer resin may be used alone, or may be used by mixing other polyolefin resins as required in the above 1) to 3).

As described in JP-B-53-21021, (A) an olefin polymer (crystalline polymer) such as polyethylene, polypropylene or polymethylpentene is used as a hard segment, and (B) a partially crosslinked ethylene- An olefin elastomer obtained by using a monoolefin copolymer rubber such as a propylene copolymer rubber or an unsaturated ethylene-propylene-nonconjugated diene terpolymer rubber as a soft segment, and uniformly blending and mixing these. In addition,
Monoolefin rubber / olefin copolymer = 50/50
Mix at a ratio of ９０90/10 (weight ratio).

As described in JP-B-53-34210 and the like, (B) uncrosslinked monoolefin copolymer rubber (soft segment) and (A) olefin copolymer (crystalline, hard segment) are crosslinked. An olefin-based elastomer obtained by mixing with an agent, heating and applying shear stress to dynamically partially cross-link. In addition, (B) monoolefin rubber /
(A) Olefin-based copolymer = 60/40 to 80/20
(Weight ratio).

Further, as the thermoplastic resin used for the base sheet, a thermoplastic polyester resin can be used. Examples of the thermoplastic polyester resin include polyethylene terephthalate, polybutylene terephthalate, ethylene-terephthalate-isophthalate copolymer, and polyethylene naphthalene. Phthalates, polyester-based thermoplastic elastomers and the like can be used. The polyester-based thermoplastic elastomer is a block polymer using a high-crystalline, high-boiling aromatic polyester for the hard segment and a non-crystalline polyether having a glass transition temperature of -70 ° C or less for the soft segment. For example, polybutylene terephthalate is used for the highly crystalline and high boiling aromatic polyester, and for example, polytetramethylene ether glycol is used for the non-crystalline polyether.

In addition to the above polyolefin-based thermoplastic resins and thermoplastic polyester resins, polymethyl methacrylate, polyethyl methacrylate, nylon-
6, polyamide-based thermoplastic resins such as nylon-66, or polyimide, polyurethane, polystyrene, acrylonitrile-butadiene-styrene resin, and polyvinyl chloride.

The base sheet may be a sheet made of the thermoplastic resin alone, a sheet made of a mixture of two or more kinds, or a laminated sheet made of two or more sheets. Although it may be a body, the top plate usually has excellent design properties and various physical properties required as a top plate, and a printing layer or a surface protection layer is formed on a base sheet made of a thermoplastic resin. In addition to this, an uneven pattern is provided by embossing or the like. Therefore, the base sheet is required to be suitable for printing and embossing, and to be inexpensive. Further, when polyvinyl chloride is discarded and incinerated after use, chlorine gas and dioxin may be generated. Considering these facts, an olefin-based thermoplastic resin is suitable.

The base sheet made of a thermoplastic resin may be in a non-stretched state or in a uniaxially or biaxially stretched state, or may be colored by adding a pigment or the like. Although a sheet may be used, the thickness of the base sheet is preferably about 50 to 300 μm. If necessary, one or both surfaces of the base sheet may be subjected to corona discharge treatment, plasma treatment,
An easy adhesion treatment such as an ozone treatment may be performed. Further, the thermoplastic resin constituting the base sheet may include a known antioxidant, a light stabilizer, an ultraviolet ray inhibitor, or
Various additives of an inorganic filler for imparting flame retardancy can be added.

As the paper used for the base sheet, specifically, tissue paper, kraft paper, titanium paper, linter paper,
So-called vinyl wallpaper raw material made by sol coating or dry laminating polyvinyl chloride resin on paperboard, gypsum board paper, paper,
Examples include high quality paper, coated paper, art paper, sulfuric acid paper, glassine paper, parchment paper, paraffin paper, Japanese paper, and the like. Further, a paper-like sheet can also be used as the base sheet. Examples of the paper-like sheet include inorganic fibers such as glass fibers, asbestos, potassium titanate fibers, alumina fibers, silica fibers, and carbon fibers, and woven or nonwoven fabrics using organic resins such as polyester and vinylon.

The surface protective layer is preferably formed using a curable resin in consideration of abrasion resistance, abrasion resistance, stain resistance, and workability such as bending. Considering the combination with the sheet, an ionizing radiation curable resin is preferable because of its high energy efficiency.

The ionizing radiation-curable resin composition is obtained by appropriately mixing a prepolymer, an oligomer, and / or a monomer having a polymerizable unsaturated bond or an epoxy group in a molecule. Here, the ionizing radiation refers to an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking a molecule, and usually uses an ultraviolet ray or an electron beam.

The ionizing radiation-curable resin is specifically prepared by ionizing radiation obtained by appropriately mixing a prepolymer having a polymerizable unsaturated bond or a cationically polymerizable functional group in a molecule (including a so-called oligomer) and / or a monomer. A curable composition is preferably used. Here, the term “ionizing radiation” means an electromagnetic wave or a charged particle beam having an energy quantum that can polymerize or crosslink a molecule, and usually ultraviolet (UV) or electron beam (EB) is used.

The ionizing radiation-curable resin forming the hard coating is, specifically, a (meth) acryloyl group in the molecule,
It is composed of a monomer or prepolymer having two or more radically polymerizable unsaturated groups such as (meth) acryloyloxy groups, cationically polymerizable functional groups such as epoxy groups, or two or more thiol groups. These monomers or prepolymers may be used alone or as a mixture of two or more. Here, for example, the (meth) acryloyl group is used in the meaning of an acryloyl group or a methacryloyl group.

Examples of the prepolymer having a radical polymerizable unsaturated group include polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth)
Acrylate, melamine (meth) acrylate, triazine (meth) acrylate, silicon (meth) acrylate and the like can be used. The molecular weight is usually 250 to 1
Those of about 00,000 are used.

Examples of the prepolymer having a cationically polymerizable functional group include prepolymers such as epoxy resins such as bisphenol type epoxy resin and novolak type epoxy resin, and vinyl ether type resins such as aliphatic vinyl ether and aromatic vinyl ether. There is.

Examples of monofunctional monomers having a radical polymerizable unsaturated group include, for example, monofunctional monomers of (meth) acrylate compounds, such as methyl (meth) acrylate and 2-ethylhexyl (meth). There are acrylate, phenoxyethyl (meth) acrylate and the like.

Examples of the polyfunctional monomer having a radically polymerizable unsaturated group include diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and trimethylolpropane ethylene oxide. There are tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

Examples of the monomer having a thiol group include:
There are trimethylolpropane trithioglycolate, dipentaerythritol tetrathioglycolate and the like.

When curing with ultraviolet light or visible light, a photopolymerization initiator is added to the ionizing radiation-curable resin. In the case of a resin system having a radical polymerizable unsaturated group,
As the photopolymerization initiator, acetophenones, benzohenones, thioxanthones, benzoin, benzoin methyl ether and the like can be used alone or in combination.
In the case of a resin having a cationically polymerizable functional group,
As the photoinitiator, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metaceron compound, a benzoin sulfonic acid ester or the like can be used alone or as a mixture. The addition amount of these photopolymerization initiators is about 0.1 to 10% by weight based on 100% by weight of the ionizing radiation-curable resin.

Various additives are further added to the ionizing radiation-curable resin as required. As these additives, for example, a thermoplastic resin such as vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, acrylic resin, and cellulosic resin, and a constitution comprising a fine powder such as calcium carbonate, barium sulfate, silica, and alumina There are coloring agents such as pigments, dyes and pigments.

In order to adjust physical properties such as flexibility and surface hardness when the ionizing radiation-curable resin composition is applied and cured, a resin not cured by ionizing radiation irradiation is added to the ionizing radiation-curable resin composition. It can also be added. Examples of specific resins include the following. Thermoplastic resins such as polyurethane resin, cellulose resin, polyvinyl butyral resin, polyester resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate. Above all, addition of a polyurethane resin, a cellulose resin, a polyvinyl butyral resin or the like is preferable from the viewpoint of improving flexibility.

As the solvent for the ionizing radiation-curable resin, those commonly used in paints, inks and the like can be used. Specifically, aromatic hydrocarbons such as toluene and xylene, acetone, methyl ethyl ketone, and the like can be used. Ketones such as methyl isobutyl ketone and cyclohexanone; acetates such as ethyl acetate, isopropyl acetate and amyl acetate; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; ethers such as dioxane, tetrahydrofuran and diisopropyl ether; Mixtures of two or more can be mentioned.

As a method for forming a surface protective layer with the ionizing radiation-curable resin, for example, a solution of the ionizing radiation-curable resin is applied and coated by a well-known coating method such as a gravure coating method or a roll coating method. Can be formed. The coating amount in this case is approximately 5 to 30 g / m ² as solid content, preferably 7 to 20 g / m ² .
² The reason for this is that if the coating amount is less than 5 g / m ² , the surface hardness decreases and the scratch resistance and abrasion resistance decrease, and if the coating amount exceeds 30 g / m ² , the flexibility decreases, Workability such as bending deteriorates.

When the surface protective layer made of a cross-linked cured product of an ionizing radiation-curable resin is to be further provided with abrasion resistance and abrasion resistance, powdered aluminum oxide, silicon carbide, silicon dioxide, etc. , Calcium titanate, barium titanate, magnesium pyroborate, zinc oxide, silicon nitride, zirconium oxide, chromium oxide, iron oxide, boron nitride, diamond, and diamond sand. The ratio of this abrasive material to 100 parts by weight of the ionizing radiation-curable resin is suitably from 0.1 to 80 parts by weight.

The particle shape of the abrasive material may be any shape such as a sphere, a polygon, a scale, etc., but a sphere is preferable in order to prevent abrasion of the coater itself for coating.
For example, as described in Japanese Patent No. 274093, a spherical α-
Alumina is mentioned. The average particle size of the abrasive is 3 to
It is preferably about 30 μm.

The ionizing radiation-curable resin described above may include, if necessary, a colorant such as a paint or a pigment, a gloss adjusting agent,
Additives such as fillers such as extenders, defoamers, leveling agents, and thixotropic agents can be added.

As the ultraviolet light source, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, and a metal halide lamp can be used.
Usually, the wavelength range of 1900 to 3800 ° is mainly used as the wavelength of ultraviolet rays. As the electron beam source, Cockloft-Walton type, Handicraft type, Resonant transformer type, Insulated core transformer type, or Linear type, Dynamitron type,
Using various types of electron beam accelerators such as high frequency type, 100-100
One that irradiates electrons having an energy of 0 KeV, preferably 100 to 300 KeV can be used.

For the purpose of improving the adhesive strength between the base sheet and the surface protective layer, a primer layer may be provided between them. This primer layer is formed of a resin comprising a copolymer of an acrylic resin and a urethane resin, and isocyanate. That is, a copolymer of an acrylic resin and a urethane resin is obtained by blending an acrylic polymer component having a hydroxyl group at the terminal (component A), a polyester polyol component having a hydroxyl group at both terminals (component B), and a diisocyanate component (component C). To give a prepolymer, which is obtained by further adding a chain extender (component D) such as a diamine to the prepolymer to extend the chain. This reaction forms polyester urethane. Since the acrylic polymer component is introduced into the molecule to form an acrylic-polyester urethane copolymer having a hydroxyl group at a terminal, the terminal hydroxyl group of the acrylic-polyester urethane copolymer is reacted with isocyanate and cured. Is formed.

As the component A, a linear acrylate polymer having a hydroxyl group at a terminal is used. Specifically, linear polymethyl methacrylate (PMMA) having a hydroxyl group at a terminal is preferable because it has excellent weather resistance (particularly properties against light degradation) and is easily copolymerized with urethane and made compatible. . The component A is an acrylic resin component in the copolymer, and has a molecular weight of 5,000.
Those having a weight-average molecular weight of from 7000 to 7000 are preferably used because they have particularly good weather resistance and adhesiveness. In addition, the component A may use only one having a hydroxyl group at both ends, but may also use one having a conjugated double bond remaining at one end mixed with the above one having a hydroxyl group at both ends. Good. By mixing an acrylic polymer having a conjugated double bond remaining, when an ionizing radiation-curable resin is used as a layer in contact with the primer layer, for example, a resin for the surface protective layer, the ionizing radiation-curable resin and the acrylic polymer are used. When the surface protective layer is formed using an ionizing radiation-curable resin, a primer layer is provided. Is more desirable.

The component B reacts with diisocyanate to form a polyester urethane, and forms a urethane resin component in the copolymer. As the component B, a polyester diol having a hydroxyl group at both terminals is used. Examples of the polyester diol include a diol compound having an aromatic or spiro ring skeleton and a lactone compound or a derivative thereof,
Or an addition reaction product with an epoxy compound, a condensation product of a dibasic acid and a diol, and a polyester compound derived from a cyclic ester compound.
Examples of the diol include short-chain diols such as ethylene glycol, propylene glycol, diethylene glycol, butanediol, hexanediol and methylpentanediol, and short-chain alicyclic diols such as 1,4-cyclohexanedimethanol. Examples of the dibasic acid include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, and the like. Preferred as the polyester polyol is adipic acid or a mixture of adipic acid and terephthalic acid as the acid component, particularly preferably adipic acid, and an adipate-based polyester using 3-methylpentanediol and 1,4-cyclohexanedimethanol as the diol component. .

In the primer layer, the urethane resin component formed by the reaction between the components B and C gives the primer layer flexibility and contributes to the adhesion to the base sheet. The acrylic resin component composed of an acrylic polymer contributes to weather resistance and blocking resistance in the primer layer. In the urethane resin, the molecular weight of the component B may be any range as long as a urethane resin capable of sufficiently exhibiting flexibility in the primer layer is obtained, and adipic acid or a mixture of adipic acid and terephthalic acid, 3-methylpentanediol and In the case of a polyester diol comprising 1,4 cyclohexane dimethanol, 500 to 5000
(Weight average molecular weight) is preferred.

As the component C, an aliphatic or alicyclic diisocyanate compound having two isocyanate groups in one molecule is used. Examples of the diisocyanate include tetramethylene diisocyanate, 2,2,4
(2,4,4) -1,6 hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4'cyclohexyl diisocyanate, and the like. As the diisocyanate component, isophorone diisocyanate is preferred because of its excellent physical properties and cost. Component A above
The equivalent ratio of the isocyanate group to the total hydroxyl group (including amino group) of the acrylic polymer, polyester polyol, and the chain extender described below in the case of reacting -C is such that the isocyanate group becomes excessive. .

The above three components A, B and C are heated at 60 to 120 ° C.
When the reaction is carried out for about 2 to 10 hours, the isocyanate group of the diisocyanate reacts with the hydroxyl group at the terminal of the polyester polyol to form a polyester urethane resin component, and a compound in which the diisocyanate is added to the hydroxyl group at the terminal of the acrylic polymer is also mixed. Is formed in a state where the isocyanate group and the hydroxyl group remain. As a chain extender to this prepolymer, for example, a diamine such as isophorone diamine or hexamethylene diamine is added to react an isocyanate group with the chain extender, and the acrylic polymer component is extended in the molecule of the polyester urethane by chain extension. An acrylic-polyester urethane copolymer which has been introduced and has a hydroxyl group at a terminal can be obtained.

The acrylic-polyester urethane copolymer is added with an isocyanate, and a coating liquid adjusted to a necessary viscosity in consideration of a coating method and a coating amount (after drying) is obtained. A primer layer can be formed by applying a known coating method such as a roll coating method. The coating amount after drying of the primer layer is suitably from 1 to 20 g / m ^2, preferably from 1 to 5 g / m ^2. Also, this primer layer
A layer may be added with additives such as a filler such as silica fine powder, a light stabilizer, and a coloring agent, if necessary, in addition to the resin. Further, as the isocyanate, any isocyanate can be used as long as it can react with hydroxyl groups of the acrylic-polyester urethane copolymer to be cross-linked and cured. For example, divalent or higher valent aliphatic or aromatic isocyanates can be used. Aliphatic isocyanates are preferred from the viewpoint of prevention and weather resistance. Specifically, tolylene diisocyanate, xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, monomers of lysine diisocyanate, or a multimer such as a dimer or trimer thereof, or And polyisocyanates such as derivatives (adducts) obtained by adding these isocyanates to polyols.

As the foamed plastic, a foamed synthetic resin such as foamed polyolefin (foamed polyethylene, foamed polypropylene) or foamed polyurethane may be used. However, foamed polyurethane is required to give the top plate the required strength. (Urethane foam) which is particularly hard is more preferable. In this urethane foam, a high molecular compound called polyurethane generated by a polyaddition reaction between a polyisocyanate and a polyol is vaporized by heat of reaction such as fluorocarbon or methylene chloride previously mixed in the raw materials during the production process, It is foamed by carbon dioxide gas generated by the reaction between a small amount of water and polyisocyanate, and a hard material is lightweight and has high strength. Then, in the present invention, two liquids are injected from holes provided in the lid plate 4 closing both ends of the hollow plate-like body, and foamed in the hollow plate-like body.

The polyurethane resin is a composition containing a polyol (polyhydric alcohol) as a main component and an isocyanate compound as a crosslinking agent (curing agent). As the polyol, those having two or more hydroxyl groups in the molecule, basically, a monomer diol, a triol or the like, and a polymer diol containing a chain of alkylene repeating units mainly contributing to the molecular weight thereof, Contains triol. Typical polymeric foliols consist essentially of either linear or branched chains of the above repeating units terminated with hydroxy groups, preferably monomers having 2, 3, 4 or more hydroxy groups Contains polyol. For example, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, 1,2,6-hexanetriol, butenediol, turucose, glucose, sorbitol, pentaerythritol, mannitol, triethanolamine, n-methyldimethanolamine, and rings Formulas include aromatic and aliphatic and triols. Further, polyethylene glycol, polypropylene glycol, acrylic glycol, polyester polyol, polyether polyol and the like are used.

On the other hand, as the isocyanate compound, a polyvalent isocyanate compound having two or more isocyanate groups in a molecule is used. For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate,
Aromatic isocyanates such as polyphenylmethane polyisocyanate and xylylene diisocyanate, called crude MDI; aliphatics such as isophorone diisocyanate, hexamethylene diisocyanate; Alicyclic isocyanate compounds, hydrogenated tolylene diisocyanate, hydrogenated isocyanate compounds such as hydrogenated diphenylmethane diisocyanate, or polyisocyanate compounds and low molecular weight glycols or triols, for example, dipropylene glycol, 1,6-hexanediol,
An isocyanate adduct such as an isocyanate-terminated low molecular weight adduct obtained by reacting with 1,2,6-hexanetriol or trimethylolpropane, or an isocyanate multimer such as a tolylene diisocyanate trimer can be used.

[0053]

EXAMPLES (Example 1) In this example, a desk top plate was manufactured.

First, an acrylic-urethane resin (acrylic polyol 10) was coated on one side of a 60 μm-thick colored polypropylene film (“PB013” manufactured by Mitsubishi Kagaku MKV Co., Ltd.) having both surfaces subjected to corona discharge treatment.
A resin obtained by adding 5 parts by weight of hexamethylene diisocyanate to 0 parts by weight of the solution) was subjected to gravure coating to obtain a solid content of 2 parts.
g / m ² to form a printing primer layer. Then, on the primer layer, using a printing ink composed of an acrylic-urethane resin (a resin obtained by adding 5 parts by weight of hexamethylene diisocyanate to 100 parts by weight of an acrylic polyol), using a gravure rotary multicolor printing press to form a printed solid pattern layer. A printed sheet formed with a printed pattern layer having a wood grain pattern was prepared.

Next, an adhesive for dry lamination (Dainichi Seika Kogyo Co., Ltd.) was applied to one surface of an 80 μm thick transparent polypropylene film (“PA002” manufactured by Mitsubishi Kagaku MKV Co., Ltd.) having both surfaces subjected to corona discharge treatment. "E"
-95L ") together with 20 g / m ² to the coating the solid content,
The printed sheet was laminated by a dry lamination method such that the printed surface of the printed sheet was located on the adhesive side, to obtain a laminated sheet.

Next, a concave portion of a conduit groove is provided on the transparent polypropylene film surface of the laminated sheet, and an acrylic resin is formed on the entire surface of the transparent polypropylene film provided with the concave portion.
Urethane resin (resin obtained by adding 5 parts by weight of hexamethylene diisocyanate to 100 parts by weight of acrylic polyol)
The solution was applied by a gravure coating method so that the solid content was 2 g / m ² to form a primer layer, and an electron beam-curable resin (“EB manufactured by Dainichi Seika Kogyo Co., Ltd.”) was formed on the primer layer.
D-01 ") by a roll coating method, followed by drying, and then irradiating with an electron beam in an environment having an oxygen concentration of 200 ppm or less, so that the decorative sheet has a surface protective layer having a solid content of 15 g / m ^2. Was prepared.

Subsequently, the degreasing-treated S having a thickness of 0.4 mm
The decorative sheet prepared above was adhered to the surface of the E steel sheet in a state where the surface protective layer was exposed. Specifically, an epoxy-isocyanate-based adhesive was applied to the surface of the steel sheet at a solid content of 10 g / m ^2, and a decorative sheet was adhered by pressure bonding to produce a decorative steel sheet. Then, fitting portions were formed on both sides of the decorative steel plate to obtain a front plate. During the bending process, the decorative sheet did not break or crack.

A back plate was manufactured by forming fitting portions on both sides of a 0.3 mm thick colored steel plate with fitting portions of the front plate. Then, these front plates form a hollow plate-like material by fitting with a back plate, and after closing the openings at both ends thereof with a cover plate, two liquids for forming urethane foam from holes provided in the cover plate are formed. It was poured and foamed in a hollow plate to obtain a top plate. Here, "Sofran-R" manufactured by Toyo Tire & Rubber Co., Ltd. (polyol component: 831-23E, isocyanate component: M
IC) was used.

The desk top plate manufactured in this manner had overall strength and excellent surface hardness. In addition, dry wiping of oily black magic ink (registered trademark) was possible.

Example 2 Also in this example, a desk top plate was manufactured.

First, a solid ink layer was formed on one surface of a paper impregnated with an acrylic resin latex having a basis weight of 50 g / m ² by a gravure rotary multicolor printing press, and a pattern ink layer was formed on the solid ink layer. The solid ink layer uses an ink obtained by adding a pigment mainly composed of titanium white, red iron oxide, and benzidine yellow to a resin binder of a mixture of an acrylic resin and a nitrified cotton, and has a coating amount of 4 g / m ² (when dried). It was formed by coating. The pattern ink layer was formed by printing a wood-grain pattern of a cedar board using an ink obtained by adding carbon black and a pigment mainly composed of a red stalk to a resin binder made of nitrified cotton.

After the pattern ink layer was formed as described above, a surface protective layer was formed covering the pattern ink layer. In particular,
Using a gravure roll coater, paint 3
After coating at 0 g / m ² (at the time of drying), using a scanning type electron beam irradiation device, an electron beam of 175 keV was applied for 5 Mr.
The coating film was cross-linked and cured by ad irradiation to form a surface protective layer. The thickness of the coating film is 10 μm (when cured), the coating film is crosslinked and cured by electron beam, and the average crosslinker molecular weight is 272.
Is a three-dimensional network polymer.

<Coating Formulation> Bifunctional bisphenol A epoxy acrylate prepolymer 20 parts by weight Bifunctional phenolic epoxy acrylate 20 parts by weight Trimethylolpropane triacrylate 20 parts by weight Urethane acrylate (molecular weight 1700) 20 parts by weight Silicon acrylate 0.8 Parts by weight Spherical α-alumina particles (average particle size 25 μm) 15 parts by weight

Here, the urethane acrylate composition used in the above-mentioned coating composition is as follows.

<Urethane acrylate composition> Polytetramethylene glycol (molecular weight 1000) 1000 parts by weight Isophorone diisocyanate 444 parts by weight 2-hydroxyethyl acrylate 232 parts by weight

After a decorative sheet having a surface protective layer was prepared as described above, a decorative steel sheet was prepared by attaching the decorative sheet to the surface of the steel sheet in the same manner as in Example 1. A decorative top plate for a desk was manufactured in the same procedure as described above.
The top plate manufactured in Example 2 had overall strength, high surface hardness, and extremely excellent wear resistance. Also,
Dry wiping of oily black magic ink was possible.

[0067]

The top plate according to the first aspect of the present invention is characterized in that a hollow plate is formed of a metal plate, and the hollow plate is filled with foamed plastic. In addition to being able to achieve weight reduction, it is possible to have sufficient strength.

The top plate according to the second aspect of the present invention is the top plate according to the first aspect, wherein the hollow plate-like body is formed by fitting the front plate with the fitting portions formed on both sides to the fitting on both sides. And a back plate with a mating part that fits into the part. The openings at both ends of the back plate are closed by a lid plate. The cost can be reduced by using a coated steel plate for the back plate.

The top plate according to the third aspect of the present invention is characterized in that, in the top plate according to the first or second aspect, a reinforcing material is provided in the hollow plate-like body. In addition to the effect, since the strength of the top plate is increased, the effect of withstanding a large load is exhibited.

A top plate according to a fourth aspect of the present invention is the top plate according to any one of the first to third aspects, wherein the surface protective layer comprises a cross-linked cured product of an ionizing radiation-curable resin on the surface of the metal plate. It is characterized by sticking a decorative sheet formed with, in addition to the above-mentioned effects, it can be produced without breaking or cracking of the decorative sheet, and has excellent surface hardness and stain resistance, This has the effect of reducing adverse effects on the environment when disposed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a top plate according to the present invention.

FIG. 2 is a perspective view showing a part of a portion cut along XX of FIG. 1;

FIG. 3 is a sectional view of a decorative sheet to be attached to a front plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top plate 2 Top plate 2a Fitting part 3 Back plate 3a Fitting part 4 Lid 5 Foam plastic 6 Reinforcement 10 Metal plate 20 Decorative sheet 21 Base sheet 22 Surface protective layer

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3B053 PA05 PA06 PB01 PB02 PB05 PB06 PC02 PC04 PC05 4F100 AB01A AB01C AB03 AK01B AK01D AK07 AK25 AK51 AK51G AK53G AT00E BA03 BA04 BA05 BA06 BA07 BA10A BA10CEJD BA10 BAJC EJD EJ65 GB08 GB81 HB00 HB00D HB01 HB31 JB14D JK01 JK12 JK14 JL00 JL02 JL03 JL06 JL16

Claims (4)

[Claims] 1. A top plate wherein a hollow plate is formed by a metal plate, and the hollow plate is filled with foamed plastic. 2. A hollow plate-like body comprising: a front plate having a fitting portion formed on both sides; and a back plate having a fitting portion formed on both sides to be fitted with the fitting portion. The top plate according to claim 1, wherein the portion is closed by a lid plate. 3. The top plate according to claim 1, wherein a reinforcing material is provided in the hollow plate-like body. 4. A top sheet according to claim 1, wherein a decorative sheet having a surface protective layer formed of a crosslinked and cured product of ionizing radiation-curable resin is formed on a surface of a metal plate. Board.