JP6831342B2 - Decorative board with magnetic layer - Google Patents

Description

The present invention relates to a decorative board having a magnetic layer on the back surface.

Conventionally, melamine decorative boards using melamine resin impregnated decorative paper, phenol resin impregnated paper and the like as laminated materials have been used for desks, tables, counters and the like.
In recent years, a nonflammable decorative board that imparts nonflammability to a melamine decorative board has been known, and further, by providing a magnetic layer on the back surface of the melamine decorative board, it can be easily attached to and removed from a metal wall surface such as an elevator. There are also known decorative sheets that can be easily installed.

Japanese Unexamined Patent Publication No. 2013-180429

However, it cannot be easily adhered to a metal wall surface, and if an adhesive layer is provided on the back surface of a decorative sheet with an adhesive, the non-combustible test of the Building Standards Act cannot be cleared (total calorific value of 8 MJ / m ² or less). However, there was a problem that the shape could not be maintained and it failed).

The present invention has been studied in view of such a situation, and a decorative board having an adhesive layer on the back surface of the decorative board, a magnetic layer under the adhesive layer, and a magnetic layer that can be easily applied to a metal wall surface is provided. An invention for the purpose of providing the present invention, the present invention comprises a decorative sheet with an adhesive containing a decorative board layer and an adhesive layer, and a magnetic layer. The decorative board layer includes a decorative layer and a mixed paper layer. The decorative layer is made of a heat-curable resin-impregnated decorative paper containing a heat-curable resin in the decorative paper, and the mixed paper layer is made of a magnesium silicate mixed paper having bound water as a base material and is a nitrogen-based flame retardant or phosphorus / nitrogen-based difficult. The above-mentioned problem can be solved by using a decorative board having a magnetic layer, which is made of a flame-retardant mixed paper impregnated with a fuel agent and contains a magnetic layer on the back surface side of the pressure-sensitive adhesive layer.

The decorative plate having the magnetic layer of the present invention is easy to process even if the plate thickness is thin, and by providing the magnetic layer, it can be easily applied to a metal wall surface, and a decorative plate with an adhesive containing the decorative plate layer and the adhesive layer. The sheet has excellent balance, low warpage, and excellent nonflammability.

Further, the decorative board is usually composed of a decorative layer, a core layer, a surface layer, an intermediate layer, a lining layer, etc., if necessary, and all of them use resin-impregnated paper containing a thermosetting resin or a thermoplastic resin. The mixed paper layer used in the invention is made of magnesium silicate mixed paper having bound water as a base material, and is a nitrogen-based flame retardant without resin impregnation, or a flame retardant mixed paper impregnated paper containing a phosphorus / nitrogen flame retardant, which is a decorative layer and a core layer. There was an unexpected effect such as excellent interlayer adhesion.

In addition, thermosetting resins and thermoplastic resins have heat shrinkage peculiar to resins, and the dimensions of the decorative plate layer are larger when the flame retardant mixed paper impregnated paper is used than when the resin is not impregnated or impregnated with the resin. It has the effect of being excellent in stability.

Furthermore, the decorative board having the magnetic layer of the present invention has the performance of passing the flameproof performance test of the Fire Service Act Construction Regulations (Applying Article 4-3).

FIG. 6 is a structural sectional view of a decorative sheet with an adhesive according to the present invention. FIG. 6 is a structural sectional view of a decorative board having a magnetic layer of the present invention. (Anisotropy magnetic sheet) FIG. 6 is a structural sectional view of a decorative board having another magnetic layer of the present invention. (Isotropic magnetic sheet) A photograph showing the translucency of Example 4. A photograph showing the translucency of Comparative Example 4.

For the decorative layer according to the present invention, a resin solution containing a thermosetting resin as a main component, such as an amino-formaldehyde resin, a diallyl phthalate resin, an unsaturated polyester resin, or a mixed resin thereof, is used for a thermosetting resin decorative board. A resin-impregnated decorative paper obtained by impregnating 30 to 140 g / m ² of the decorative paper with a resin impregnation is used so that the impregnation rate shown in Equation 1 is 80 to 300%. Among the resins, an aminoamino-formaldehyde resin having excellent heat resistance, abrasion resistance and the like is particularly preferable. The amino-formaldehyde resin can be obtained by condensing formaldehyde with an amino compound such as melamine, urea, acetoguanamine or benzoguanamine.
Particularly preferred is a melamine-formaldehyde resin having excellent water resistance, heat resistance, abrasion resistance, chemical resistance, stain resistance, and light resistance.

For the mixed papermaking layer according to the present invention, a flame retardant-impregnated paper obtained by impregnating a heat-resistant fibrous base material with a flame retardant is used. By using the flame retardant impregnated paper, it is possible to obtain a good balance and suppress the warp of the finished decorative board.

The content of the nitrogen-based flame retardant or phosphorus / nitrogen-based flame retardant or thermosetting resin in the mixed paper layer (weight of the flame retardant or thermosetting resin contained in the mixed paper layer of a unit area) is 9 to 90 g / m. It should be ² . Within this range, the warp of the decorative board can be suppressed and the flexibility is excellent. The content is a solid content value.

As a heat-resistant fibrous base material, a slurry containing pulp and a silicic acid compound having bound water as main components and a coagulating binder, chemicals, organic fibers, inorganic fibers, fixing agents, etc. is added to a round net paper machine. Use a 60-400 g / m ² mixed paper machine that has been dehydrated and dried by making paper with a net multi-cylinder paper machine, a long net-circle net combination paper machine, an inclined paper machine, or the like. The mixed paper obtained in this way has self-extinguishing properties and can suppress the spread of flames. Examples of pulp include natural pulp such as wood pulp, cotton pulp, and vegetable fiber pulp. In particular, chemical pulp obtained by chemically treating wood pulp having a short fiber length such as broadleaf bleached kraft pulp and coniferous kraft pulp is used. It is strong, has excellent impregnation suitability, and is preferable. Hardwood bleached kraft pulp and softwood kraft pulp may be used in combination, and may be bleached or unbleached.

Examples of the silicate compound having bound water include hydrous magnesium silicate [Mg ₈ Si ₁₂ O ₃₀ (OH ₂ ) ₄ (OH) ₄ 6 to 8H ₂ O] (sepiolite) and hydrous magnesium silicate [Mg ₃ Si ₄ O ₁₀ (OH 2). ) _2] (talc), hydrated magnesium aluminum silicate _{[Mg 5 Si 8 O 2 0} (OH) 2 (H 2 O) 4 · 4H 2 O] ( attapulgite), water-containing aluminum silicate [(Mg, Ce, _{Al) 3 (Al, Si) 4 O 10} (OH) 2 · 4H 2 O] ( vermiculite) hydrous magnesium silicate compound such as and the like. In particular, sepiolite is preferable because it is nonflammable and has excellent water resistance. The mixed production ratio of the silicic acid compound having the bound water and the pulp is preferably 40 to 95% by weight, more preferably 55 to 85% by weight. If it is less than 40% by weight, the noncombustible performance tends to decrease, and if it exceeds 95% by weight, the paper strength tends to decrease.

As the flame retardant, a phosphorus-based flame retardant, a nitrogen-based flame retardant, and a phosphorus / nitrogen-based flame retardant are preferably used. Phosphate-based flame retardants include phosphoric acid esters, phosphorus-containing polyols and phosphorus-containing amines, nitrogen-based flame retardants include melamine cyanurate, triazine compounds and guanidine compounds, and phosphorus-nitrogen flame retardants include guanidine phosphate and guanyl urea phosphate. Be done. Phosphorus / nitrogen flame retardant is a compound that has the functions of both phosphorus flame retardant and nitrogen flame retardant. It has both phosphorus atom and nitrogen atom in one molecule, and phosphorus has a strong dehydrating action when exposed to high temperature. Oxygen is blocked by, nitrogen generates ammonia gas, etc., and oxygen can be blocked, so the heat insulation and flame retardant effect is improved and the prepreg is made hard to burn.

The reason why the interlayer adhesion between the decorative layer and the core layer is excellent despite being impregnated with the flame retardant is not clear, but the thermosetting resin contained in the flame retardant and the decorative layer and the thermoplasticity contained in the core layer. and the resin reacts, tightly bound to have, or decorative layer amino to - impregnated formaldehyde resins, amino dried - formaldehyde resin impregnated paper, nitrogen-based flame retardants, phosphorus-nitrogen based as a flame retardant in the composite paper layer When a flame retardant is used, the amino group contained in the decorative layer and the nitrogen contained in the mixed paper layer are deeply involved and bonded with the thermoplastic resin or silane coupling agent or flame retardant contained in the core layer. It seems to be doing. In order to judge the interlayer adhesion, JIS K 6902 is usually subjected to a boiling resistance test, but in Comparative Example 2 which is not impregnated with a flame retardant, the layers are easily delaminated by hand after thermal pressure molding to boil resistance. There was no need to do a sex test.

The core layer uses one or more dried prepregs in which a fibrous base material is impregnated with a thermoplastic resin as a binder component and a slurry containing an endothermic metal hydroxide as an essential component.

Examples of the fibrous base material include an organic fiber base material and an inorganic fiber base material, and examples of the organic fiber base material include polyethylene, polypropylene, vinylon, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyamide, and polyester. , Polypropylene and the like, these modified products, fibers made of various copolymers typified by polyethylene-vinyl acetate copolymers and the like, and mixtures thereof.

Examples of the inorganic fiber base material include non-woven fabrics and woven fabrics made of inorganic fibers such as glass fiber, rock wool and carbon fiber, and the basis weight of the inorganic fiber base material is in the range of 10 to ²⁰⁰ g / m ² . preferable. When the inorganic fiber base material is used, the nonflammability of the decorative board is further improved as compared with the case where the organic fiber base material is used. Among the inorganic fiber base materials, especially when a glass fiber non-woven fabric is used, the warp of the finished decorative board is suppressed without the fiber direction, and the heat resistance, flame resistance, and slurry impregnation property are further improved.

Acrylic resin emulsion is preferably used as the thermoplastic resin as the binder component. In particular, it is more preferable to use an acrylic resin emulsion having a glass transition temperature (Tg) of −20 ° C. or higher because the adhesion and moldability are improved. Among them, it is more preferable to use an acrylic resin emulsion having an average particle size of 150 to 300 nm because the binding force of the core layer and the bendability and smoothness of the decorative board can be further improved. It can be inferred that the reason why the smoothness is improved is that the acrylic resin emulsion is fine particles. The average particle size is a value calculated based on the scattered light detected during laser irradiation using a laser light diffraction / scattering type particle size measuring device (ELS-8000 manufactured by Otsuka Electronics Co., Ltd.).

It is desirable that the mixing ratio of the thermoplastic resin is 3 to 17% by weight in the slurry in terms of solid content, and if it is not more than the upper limit, the nonflammability is further improved and the synthetic resin exudes during thermal pressure molding. Things are less likely to happen. Further, when it is at least the lower limit, the adhesion between the prepregs is further improved, and the amount of the slurry impregnated into the fibrous base material is more easily controlled.

The amount of the thermoplastic resin contained in the core layer (weight of the thermoplastic resin contained in the core layer of a unit area) is 10 to 100 g / m ² . When it is 100 g / m ² or less, the nonflammability of the decorative board is further improved. Further, when the amount is 100 g / m ² or less, when the decorative board is manufactured by thermal pressure molding, the thermoplastic resin is less likely to seep out.

Further, when the amount of the thermoplastic resin contained in the core layer is 10 g / m ² or more, the adhesion between the prepregs is further improved when the core layer is manufactured from the prepreg. Further, when the content is 10 g / m ² or more, when the fibrous base material is impregnated with the slurry to produce the core layer, the amount of the slurry impregnated can be controlled more easily.

Endothermic metal hydroxides contain water of crystallization, decompose at high temperatures and release water. Since the reaction is an endothermic reaction, it has the effect of suppressing a temperature rise during combustion, and improves the nonflammability of the decorative board of the present invention. Examples of the heat-absorbing metal hydroxide include aluminum hydroxide, magnesium hydroxide, calcium hydroxide and the like as described above, and aluminum hydroxide and magnesium hydroxide are particularly preferably used. When the blending ratio of the endothermic metal hydroxide in the slurry is 20 to 95% by weight, the decorative board has good adhesion and nonflammable performance.

The average particle size of the endothermic metal hydroxide can be, for example, in the range of 1 to 50 μm. This average particle diameter is an arithmetic mean diameter calculated from the particle size distribution (volume distribution) detected by the laser diffraction / scattering method (microtrack method). When the average particle size of the endothermic metal hydroxide is within the above range, the dispersibility of the endothermic metal hydroxide in the slurry is improved, and the impregnation property of the slurry into the fibrous substrate is improved. .. In addition, the surface of the decorative board has a smooth finish.

The amount of endothermic metal hydroxide contained in the core layer (weight of the endothermic hydroxide contained in the core layer of a unit area) is preferably in the range of 50 to 600 g / m ² . Within this range, when the core layer is manufactured from the prepreg, the adhesion between the prepregs can be improved, and the non-combustible performance of the decorative board can be improved.

The slurry may also contain an inorganic filler other than the endothermic metal hydroxide, a silane coupling agent, a flame retardant, and the like.

Examples of the inorganic filler include carbonates such as calcium carbonate, magnesium carbonate and zinc carbonate, silica, talc, fly ash and the like. The average particle size of the inorganic filler (arithmetic mean diameter calculated from the particle size distribution (volume distribution) detected by the laser diffraction / scattering method (microtrack method)) is, for example, in the range of 0.05 to 20 μm. be able to. In this case, the suitability for impregnating the slurry into the fibrous base material is further improved.

Among the inorganic fillers, carbonates, for example calcium carbonate, can be selected in particular. In this case, workability and machinability in the manufacturing process of the decorative board are further improved. As the calcium carbonate, heavy calcium carbonate, light calcium carbonate (precipitated calcium carbonate) and the like can be used. The average particle size of calcium carbonate can be, for example, 0.05 to 10 μm, more preferably 0.1 to 5 μm. By setting the thickness to 0.05 μm or more, aggregation of calcium carbonate is less likely to occur in the slurry, and the impregnation property of the slurry into the fibrous substrate is improved. Further, when the thickness is 10 μm or less, the surface of the decorative board becomes smoother and the appearance is improved.

The light calcium carbonate means calcium carbonate chemically produced by firing limestone, and the heavy calcium carbonate means fine powdered calcium carbonate produced by dry or wet crushing white crystalline calcium.

The blending ratio of the endothermic metal hydroxide in the total inorganic filler contained in the preprig can be 30 to 100% by weight. Within this range, the nonflammability and machinability of the decorative board and the decorative sheet with an adhesive are further improved.

In the decorative board according to the present invention, a silane coupling agent can be contained in the slurry. In this case, the weight increase rate is further reduced in the boiling resistance of JIS K-6902 "Thermosetting Resin High Pressure Decorative Board Test Method" as compared with the case where the silane coupling agent is not contained, and the prepreg and the intermediate layer are used. Adhesion is further improved. The blending ratio of the silane coupling agent is in the range of 0.1 to 10% by weight in the total components of the slurry in terms of solid content.

Examples of the silane coupling agent include (meth) acryloyloxy group-containing silanes such as 3- (meth) acryloyloxypropyltrimethoxysilane and 3- (meth) acryloyloxypropyltriethoxysilane, vinyltrimethoxysilane, and vinyltri. Vinyl group-containing silanes such as ethoxysilane, epoxy group-containing silanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxy Acryloyl group-containing silane such as silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3phenylaminopropyltrimethoxysilane and other amino group-containing Examples thereof include mercapto group-containing silanes such as silane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane. In particular, when an epoxy group-containing silane or an amino group-containing silane is used, the crosslink density in the preprig is further improved.

The amount of the silane coupling agent contained in the core layer (the weight of the silane coupling agent contained in the core layer having a unit area) is preferably in the range of 1 to ²⁰ g / m ² . Within this range, the effect of the above-mentioned silane coupling agent becomes more remarkable.

The core layer can contain the same flame retardant as described above. The flame retardant preferably has a total nitrogen content of 1 to 50% by weight. The blending ratio of the flame retardant shall be in the range of 0.1 to 15% by weight of all the components of the slurry in terms of solid content. The amount of the flame retardant contained in the core layer (weight of the flame retardant contained in the core layer of a unit area) is preferably in the range of 1 to 100 g / m ² . Within these ranges, the effect of the above-mentioned flame retardant becomes more remarkable.

When the fibrous base material is impregnated with the slurry, it is impregnated in the range of 500 to 1200% by the calculation method shown in Equation 1 and dried. When it is 1200% or less, the slurry solid content is prevented from falling off from the preprig, and the preprig can be easily handled. When it is 500% or more, delamination of the preprig is less likely to occur.

The pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive and a release paper, and examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive containing an acrylic polymer and a pressure-sensitive adhesive, and a solvent rubber-based pressure-sensitive adhesive containing styrene-butadiene. Can be mentioned. Here, examples of the monomer constituting the acrylic polymer of the acrylic pressure-sensitive adhesive include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include (meth) acrylic acid alkyl esters such as butyl. Here, (meth) acrylic acid means methacrylic acid or acrylic acid. Examples of the tackifier include rosin-based, terpene-based, phenol-based, and kumaron-based tackifiers. As the release paper, a known release paper coated with a silicon release agent is used. If the thickness of the pressure-sensitive adhesive is 50 to 180 μm, the pressure-sensitive adhesive strength is exhibited.

(Explanation of magnetic layer)
The magnetic layer according to the present invention contains strontium ferrite (composite oxide of strontium and iron) as a main component, is mixed with chlorinated polyethylene as a binder component, is formed into a sheet, and is magnetized to magnetize and magnetize. It becomes a sheet. Ferrite has two types of particles, anisotropic and isotropic. The former has a hexagonal plate shape and is magnetized in only one direction, and the latter has a nearly spherical shape and is equally magnetized from any direction. Have. In the present invention, an anisotropic magnetic sheet or an isotropic magnetic sheet is used. Since the former generates a magnetic force in only one direction, it exerts a stronger attractive force, and the latter generates the same magnetic force in all directions, so that the attractive force becomes weaker. The excellent anisotropy is clear from the comparison between Example 1 and Example 3 and Example 2 and Example 4 even if the thickness is the same. The thickness of the magnetic sheet is preferably in the range of 0.32 to 3.08 mm. Within this range, the adsorption force is excellent, the weight is light, and the handling is easy.

For magnetization magnetization, a single-sided multi-pole magnetizing type in which N and S poles are alternately magnetized on only one side of the sheet and only the magnetized side is attracted, and N and S poles are applied to both sides of the sheet. Double-sided multi-pole magnetizing type that has poles magnetized alternately and can be attracted to both sides, N pole is magnetized on one side of the sheet and S pole is magnetized on the other side, and the magnetic force is in the width direction. There is a double-sided magnetizing type that comes out, and in the present invention, a single-sided multi-pole magnetizing type is preferably used.

The decorative board having the magnetic layer of the present invention is obtained by laminating a decorative layer, a mixed papermaking layer, and a glass fiber cloth base material prepreg as a core layer, if necessary, and heating with a press machine such as a flat plate press or a continuous press. After obtaining a decorative plate by pressure molding, an adhesive layer is pressure-bonded and laminated on the outside of the core layer or the mixed papermaking layer, and the magnetic layer is adhesively processed.

The laminated structure of the decorative board layer may be (B) mixed paper layer, (A) decorative layer, (B) mixed paper layer, (C) core layer, (A) decorative layer in order from the bottom, but the decorative board layer may be used. By forming the laminated structure in order from the bottom, (C) core layer, (B) mixed papermaking layer, and (A) decorative layer, the texture of the (C) core layer is less likely to appear on the surface of the decorative board, that is, excellent smoothness. There is an advantage. Further, the laminated structure of the decorative board layer is formed in the order of (B) mixed papermaking layer, (C) core layer, (B) mixed papermaking layer, and (A) decorative layer, so that the thickness becomes thicker and the bending processability becomes thicker. Although it is slightly inferior, it improves handling and is less likely to be damaged during handling.

The thickness of the decorative board layer is preferably 0.43 to 0.69 mm. When it is within this range, the curl of the decorative board having the magnetic layer can be further suppressed. In particular, when the thickness of the decorative board having a magnetic layer is within this range, the bending workability at room temperature is also excellent.
Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

(A) Decorative layer (melamine resin impregnated paper)
A decorative paper printed with a wood grain pattern having a basis weight of 100 g / m ² is impregnated with a resin solution containing a melamine-formaldehyde resin as a main component so that the impregnation rate is 130% by the calculation method defined by Equation 1. It was dried to produce melamine resin impregnated paper.

(B) Mixed paper layer 180 g / m ² magnesium silicate mixed paper (trade name: GP-18, manufactured by Tigalex Co., Ltd., hydrous magnesium silicate (sepiolite) 80% by weight, pulp 10% by weight, glass fiber 5% by weight, And organic binder 5% by weight), guanidine phosphate (Apinone 307, manufactured by Sanwa Chemical Co., Ltd., total nitrogen content 31%) as a flame retardant, with an impregnation rate of 20 by the calculation method defined in Equation 1. It was impregnated to% (36 g / m ² per unit area) and dried to produce a guanidine phosphate-impregnated mixed paper.

(C) Manufacture of core layer glass fiber cloth base material prepreg (part by weight is a solid content conversion value)
As a binder, 32 acrylic resin emulsions (product number RAX-208, manufactured by Aika Kogyo Co., Ltd.) having a glass transition temperature (Tg) of 60 ° C. and an average particle size of 200 nm containing 2-ethylhexyl acrylate and methyl methacrylate as main monomers. Weight part,
As an endothermic metal hydroxide, 300 parts by weight of aluminum hydroxide having an average particle diameter of 8 μm,
As a silane coupling agent, 2.7 parts by weight of 3-glycidoxypropyltrimethoxysilane
29 parts by weight of guanidine phosphate (Apinone 303, manufactured by Sanwa Chemical Co., Ltd., total nitrogen content 39%) was blended as a flame retardant, water was added to obtain a slurry, and then 40 g / g / as a fibrous base material. A glass fiber cloth base material prepreg was produced by impregnating the glass fiber non-woven fabric of m ^{2 so} as to have an impregnation rate of 850% by the calculation method defined in Equation 1 and drying.

From the bottom, (C) one glass fiber cloth base material prepreg as the core layer, (B) one guanidine phosphate-impregnated mixed paper as the mixed paper layer, and (A) melamine resin-impregnated cosmetic as the decorative layer. One sheet of paper was laminated and hot-press molded with a flat plate press at a temperature of 132 ° C., a pressure of 70 kgf / cm ² , and a time of 64 minutes to obtain a decorative plate having a thickness of 0.48 mm.

An adhesive sheet (manufactured by Niei Kako Co., Ltd.) having a thickness of 50 μm was prepared by applying an acrylic adhesive containing an acrylic resin as a main component on a silicone paper pattern. An adhesive sheet was attached to the core layer side (back surface) of the decorative board to obtain a decorative sheet.

Next, the release paper on the back side of the decorative sheet is peeled off, and an anisotropic magnetic sheet having a thickness of 0.4 mm containing strontium ferrite as a main component as a magnetic sheet (manufactured by Nichirei Magnet Co., Ltd., adsorption force 25 gf / cm ² or more, 2 or more) A single-sided multi-pole magnetizing type having a magnetic flux density of .45 kPa or more and a magnetic flux density of 300 Gauss or more) was adhesively processed to obtain a decorative plate having a magnetic layer.
The adsorption force is a value measured by the Yamato precision automatic scale popular type SD-800 g, and the magnetic flux density is a value measured by KENETEC GAUSS METER TM701.

In Example 1, an anisotropic magnetic sheet having a thickness of 0.6 mm containing strontium ferrite as a main component (manufactured by Nichirei Magnet Co., Ltd., attractive force 40 gf / cm ² or more, 3.92 kPa or more, magnetic flux density 360 Gauss or more). A single-sided multi-pole magnetizing type was subjected to adhesive processing to obtain a decorative plate having a magnetic layer.

In Example 1, an isotropic magnetic sheet having a thickness of 0.4 mm containing strontium ferrite as a main component as a magnetic sheet (manufactured by Nichirei Magnet Co., Ltd., attractive force 20 gf / cm ² or more, 1.96 kPa or more, magnetic flux density 250 Gauss or more). A single-sided multi-pole magnetizing type was subjected to adhesive processing to obtain a decorative plate having a magnetic layer.

In Example 1, an isotropic magnetic sheet having a thickness of 0.6 mm containing strontium ferrite as a main component (manufactured by Nichirei Magnet Co., Ltd., attractive force 30 gf / cm ² or more, 2.94 kPa or more, magnetic flux density 310 Gauss or more). A single-sided multi-pole magnetizing type was subjected to adhesive processing to obtain a decorative plate having a magnetic layer.

In Example 1, the same procedure was carried out except that a vinyl ester resin was used instead of guanidine phosphate.

Comparative Example 1
In Example 1, 110 g / m ² aluminum hydroxide mixed paper (trade name: Sunwall, manufactured by Miyoshi Paper Co., Ltd.) was used as the fibrous base material of the mixed paper layer instead of 180 g / m ² magnesium silicate mixed paper. An aluminum mixed papermaking ratio of 69% by weight) was used, and the same procedure was carried out except that a vinyl ester resin was used instead of guanidine phosphate.

Comparative Example 2
In Example 1, the same procedure was carried out except that the mixed paper layer was not impregnated with the flame retardant guanidine phosphate, but it was easily peeled off by hand after thermal pressure molding to obtain a decorative board.

Comparative Example 3
In Example 1, 110 g / m ² aluminum hydroxide mixed paper (trade name: Sunwall, manufactured by Sanzen Paper Co., Ltd., aluminum hydroxide mixed paper ratio 69% by weight) was used instead of 180 g / m ² hydrous magnesium silicate mixed paper. It was carried out in the same manner except that it was used.

Comparative Example 4
(D) Production of glass cloth base material prepreg A glass cloth (manufactured by Kurashiki Spinning Co., Ltd.) of 115 g / m ^{2 with} a glass transition temperature (Tg) of 60 ° C. and 2-ethylhexyl acrylate and methyl methacrylate as main monomers. Acrylic resin emulsion (product number RAX-208, manufactured by Aika Kogyo Co., Ltd.) having an average particle size of 200 nm is impregnated with the calculation method defined in Equation 1 so that the impregnation rate is 30%, dried, and a glass cloth base material is used. Manufactured prepreg.
The same procedure was carried out except that one sheet of (D) glass cloth base material prepreg and one sheet of (A) melamine resin-impregnated decorative paper as a decorative layer used in Example 1 were laminated in this order from the bottom.

The contents of the mixed paper layer are shown in Table 1.

The slurry composition of the core layer is shown in Table 2.

The content [g / m ² ] of each component in the core layer is shown in Table 3.

Table 4 shows the contents of the pressure-sensitive adhesive layer and the magnetic layer.

Table 5 shows the layer structure of the decorative board. The water-albalanced paper in Table 5 refers to aluminum hydroxide mixed paper.

Table 6 shows the evaluation results of the decorative board and the decorative sheet with adhesive.

Table 7 shows the evaluation results of the evaluation of the decorative board having the magnetic layer.

Table 8 shows the evaluation results of the decorative boards of Examples 4 and 5 and Comparative Example 4.

The evaluation method was as follows.
(1) Delamination strength of decorative board The presence or absence of delamination of the decorative board after thermal pressure molding was confirmed, and no delamination after thermal pressure molding was marked with ◯. A boiling resistance test (JIS K 6902: 2007 "thermosetting resin high-pressure decorative board test method") was performed. In the boiling resistance test, no abnormalities were marked as ◯.

(2) Thickness The thickness of the decorative board was measured with a micrometer.

Nonflammability (3) Total calorific value A heat-generating test of a 20-minute test was conducted on a decorative board and a decorative sheet with an adhesive using an ISO5660-compliant cone calorimeter.
(4) Shape retention In the heat generation test / evaluation method of the 20-minute test using a cone calorimeter conforming to ISO5660, the total calorific value is 8 MJ / m ² or less, and the maximum heat generation rate is 200 kW / m ² continuously for 10 seconds or more. The case where the test piece after the test does not have cracks or cracks penetrating to the back surface (the shape is retained) is marked with ○, and the case where there are cracks or cracks (the shape is not retained) is marked with ×. ..

(5) Adhesive Strength of Decorative Sheet with Adhesive A fragment having a size of 300 mm × 150 mm was cut out from the decorative sheet with adhesive. The silicone paper pattern was peeled off from the fragment, and the adhesive layer and an aluminum plate having a thickness of 2 mm were bonded together. Further, a hand roller weighing 2 kg was reciprocated twice on them. The product produced by the above steps is used as a test piece. Of the test pieces, the surface on the decorative layer side was attached to a jig of 40 mm × 40 mm using an adhesive (cyanoacrylate).

After curing for one day at a temperature of 23 ° C and a relative humidity of 50%, a Kenken-type adhesive strength tester (manufactured by Oxjack Co., Ltd.) is used to apply a force in the direction in which the aluminum plate and the adhesive layer are separated from each other. In addition, the tensile strength was measured. The value of tensile strength was used as the measured value of adhesive strength.

(6) Flameproof performance test (front and back)
According to the test method based on the 45 ° Meckel burner method, which complies with Article 4-3, Paragraphs 3 to 7 of the Fire Service Act Enforcement Regulations, the process from when the burner is removed after ignition to when the flame is raised and the burning state stops. The time (residual flame time) was measured. The elapsed time (remaining dust time) from when the burner was removed after the flame was ignited until the burning state stopped without raising the flame was measured. The area to be carbonized (carbonized area) was measured within the time from the ignition to the end of the burning state.

(7) Adsorption power A decorative plate having a 40 mm square magnetic layer was attached to the base of the steel plate, and the number of sheets that could hold A4 size plain paper was counted.
In Comparative Example 4, the decorative board itself curled violently, and the magnet was pulled toward the decorative layer side, so that the attractive force for holding the plain paper with the magnet decreased.

(8) Appearance (smoothness and translucency)
The veneer was visually observed. If there were no cracks, citron skin, or unevenness of the base in the decorative layer, the smoothness was rated as “◯”, and if there were slight irregularities, the smoothness was rated as “Δ”.
Further, a metal straightedge was applied to the back surfaces of the decorative plates of Example 4 and Comparative Example 4, the light of a fluorescent lamp was irradiated from the back surface, and the decorative plates were photographed in that state. A photograph of the decorative board of Example 4 is shown in FIG. 4, and a photograph of the decorative board of Comparative Example 4 is shown in FIG. In FIG. 5, the metal straightedge can be seen through, but in FIG. 4, it cannot be seen through. That is, since the surface of the decorative board of Example 4 has a high hiding property, the color of the base was not picked up. On the other hand, since the decorative board of Comparative Example 4 has a low hiding property, the unevenness of the glass cloth and the color of the base were picked up.

(9) Evaluation of Warpage of Decorative Board A sample of 50 mm × 300 mm was cut out from the decorative board. The fiber direction of the veneer is parallel to the lateral direction of this sample. This sample was cured for 24 hours in an environment of room temperature of 40 ° C. and humidity of 30%. The sample was then placed on a horizontal plane and one end of the sample in the longitudinal direction was pressed against the horizontal plane. Then, the distance between the opposite end of the sample in the longitudinal direction and the horizontal plane was measured. This distance is defined as the warp height. The warp height reflects the size of the curl of the sample.

(10) Dimensional change rate JIS K 6902: 2007 Measured based on the dimensional stability test of "Thermosetting resin high-pressure decorative board test method".

1 Decorative layer 2 Mixed paper layer 3 Core layer 5 Adhesive layer 6 Decorative board layer 7 Decorative sheet with adhesive 8 Anisotropic magnetic layer 9 Isotropic magnetic layer 21 Decorative board with magnetic layer 22 Decorative board with magnetic layer

Claims (18)

A decorative sheet with an adhesive containing a decorative board layer and an adhesive layer, and a magnetic layer are provided. The decorative board layer includes a decorative layer and a mixed papermaking layer, and the decorative layer is a thermosetting resin on the decorative paper. made of a thermosetting resin impregnated decorative paper containing the composite paper layer after the magnesium silicate composite paper with base nitrogen Motokei flame retardant, or phosphorus-nitrogen flame retardant the flame retardant impregnation mixed paper having a bound water A decorative board having a magnetic layer, which comprises a magnetic layer on the back surface side of the pressure-sensitive adhesive layer. The decorative board having a magnetic layer according to claim 1, further comprising a core layer made of a prepreg containing a fibrous base material. The decorative board having a magnetic layer according to claim 2, wherein the laminated structure of the decorative board layer is the core layer, the mixed papermaking layer, and the decorative layer in this order from the back surface side. The decorative board having a magnetic layer according to claim 1, wherein the content of the nitrogen-based flame retardant or the phosphorus / nitrogen-based flame retardant in the mixed paper layer is 9 to 90 g / m ² . The decorative board having a magnetic layer according to claim 4, wherein the phosphorus / nitrogen flame retardant in the mixed paper is composed of one or more selected from the group of guanidine phosphate and guanyl urea phosphate. The decorative board having a magnetic layer according to claim 1, wherein the phosphorus / nitrogen flame retardant in the mixed paper is guanidine phosphate. The decorative board having a magnetic layer according to claim 1, wherein the thermosetting resin is an amino-formaldehyde resin. The decorative board having a magnetic layer according to claim 7, wherein the amino-formaldehyde resin is a melamine-formaldehyde resin. The decorative board having a magnetic layer according to claim 2, wherein the prepreg of the core layer contains a heat-absorbing metal hydroxide and a binder component in the fibrous base material. The decorative board having a magnetic layer according to claim 9, wherein the binder component contains an acrylic resin emulsion. The decorative board having the magnetic layer according to any one of claims 2, 3 or 9 , wherein the core layer contains a flame retardant. The decorative board having a magnetic layer according to claim 11 , wherein the content of the flame retardant is 1 to 100 g / m ² . The decorative board having a magnetic layer according to claim 11 or 12 , wherein the flame retardant is a nitrogen-based flame retardant or a phosphorus / nitrogen-based flame retardant. The decorative board having a magnetic layer with an adhesive according to claim 13 , wherein the nitrogen content of the phosphorus / nitrogen flame retardant is 1 to 50% by mass. The decorative board according to claim 14, wherein the phosphorus / nitrogen flame retardant is guanidine phosphate. The decorative board having a magnetic layer with an adhesive according to any one of claims 1 to 3, wherein the thickness of the decorative board layer is 0.43 to 0.69 mm. The decorative board having the magnetic layer according to claim 1, wherein the magnetic layer is an anisotropic magnetic sheet. The decorative board having the magnetic layer according to claim 1 or 17 , wherein the thickness of the magnetic layer is 0.32 mm to 3.08 mm.