JP2015189221A - Mirror surface decorative sheet, and mirror surface decorative plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror surface decorative sheet having excellent specularity and designability, excellent working characteristics with no occurrence of cracks at the time of processing, and excellent surface characteristics, and to provide a mirror surface decorative plate using the same.SOLUTION: The mirror surface decorative sheet comprises at least a substrate sheet and a surface protective layer. The substrate sheet is composed of a crystalline resin having a glass transition temperature (Tg) of -50 to 130°C and a melting point (Tm) of higher than 220°C. The surface protective layer is a cured material of an ionizing radiation-curable resin composition, shows elongation of 40% or less at which cracks appear as measured by a specified method, and has a total thickness of 125 μm or more.

Description

  The present invention relates to a mirror surface decorative sheet and a mirror surface decorative sheet using the same.

  For various parts such as interior and exterior of buildings, building materials, furniture, or household appliances, especially for kitchen products and kitchen storage and doors, metal plates, inorganic boards (such as gypsum boards), wood boards (MDF) In addition, a plastic sheet is used as a base material on a substrate such as a particle board or a laminated board, and a decorative sheet to which a beauty is imparted by giving a color, a pattern, or unevenness is used. For these members, in addition to surface properties such as weather resistance, stain resistance, scratch resistance, and solvent resistance and design properties, bending processing required for bonding a decorative sheet to an adherend with an adhesive or When V-cut processing or lapping processing is performed, processing characteristics are required such that cracks are less likely to occur on the surface of the decorative sheet.

  In order to obtain excellent processing characteristics, a decorative sheet using an amorphous polyester resin sheet as a base material has been proposed (for example, Patent Document 1). Amorphous polyester resin sheets are generally known as soft resin sheets, and are known to be excellent in terms of processing characteristics, particularly followability. However, the amorphous polyester resin sheet has a high temperature dependency of flexibility (elastic modulus), and if it is to be processed under heating conditions in the vicinity of the glass transition point (Tg) or exceeding the glass transition point (Tg). , The softening suddenly progresses, wrinkles are generated, and excessive adherence to the adherend surface picks up so-called duck such as uneven application of glue (adhesive) or irregularities on the adherend surface, etc. There was a problem that it was inferior in terms of finish.

  By the way, with the recent increase in consumers' preference for luxury goods, mirror sheets are also required for decorative sheets used in such applications. However, since a decorative sheet based on an amorphous polyester resin sheet has high temperature dependency of flexibility (elastic modulus), the decorative sheet is heated (80 to 150 ° C.) while being wrapped on the adherend. When doing so, there is a problem that the decorative sheet is softened and it is easy to pick up the duck as described above. Therefore, even if it has specularity as a decorative sheet, there is a new problem that the specularity is remarkably lowered after being attached to an adherend, and it can be adequately addressed in terms of specularity. could not.

JP 2000-233480 A

  In general, for example, a technique of increasing the thickness of a decorative sheet or forming a multilayer structure composed of a plurality of base materials is used to reduce the specularity after being attached to an adherend. However, if the decorative sheet is made thick, the surface of the adherend can be concealed in addition to the specularity, so that an excellent design can be obtained, but the production efficiency is remarkably lowered, and the material cost and the transportation cost are increased. Problems arise. When it has a multi-layer structure, the occurrence of curling due to differences in heat resistance and shrinkage of a plurality of base materials and delamination problems occur.

  Furthermore, the various members as described above may be exposed to a heated state. For example, in the case of a kitchen member of a kitchen product, a heated pan or kettle may be placed directly through a pan or directly, so that the decorative sheet is also required to have heat resistance as a surface characteristic.

  Under such circumstances, the present invention has a mirror surface decorative sheet having excellent mirror characteristics and design, having excellent processing characteristics that do not cause springback and cracks during processing, and excellent surface characteristics. It is an object to provide a mirror-coated decorative board.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the problem can be solved by the following invention. That is, this invention provides the following mirror surface decorative sheet and the mirror surface decorative board using the same.

1. It has at least a base sheet and a surface protective layer, and the base sheet is made of a crystalline resin having a glass transition point (Tg) of −50 to 130 ° C. and a melting point (Tm) higher than 220 ° C. The surface protective layer is a cured product of an ionizing radiation curable resin composition, the crack generation elongation of the surface protective layer measured by the following method is 40% or less, and the total thickness is 125 μm or more. Mirror surface decorative sheet.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127 was prepared as a decorative sheet, and the test piece was measured at a tensile speed of 20 mm / min, a distance between chucks of 80 mm, and a width of 25 mm using a tensile tester in a temperature environment of 70 ° C. After pulling at an arbitrary elongation under certain conditions, the inside of the chuck is colored with a whiteboard marker, and the colored part is wiped off with a cloth. It was set as the elongation.
2. A specular decorative board comprising a substrate, an adhesive layer, and the specular decorative sheet according to 1 above in that order.

  According to the present invention, a mirror surface decorative sheet having excellent mirror properties and design properties, having excellent processing characteristics in which cracks do not occur during processing, and excellent surface characteristics, and a mirror surface decorative plate using the same are obtained. Can do.

It is a schematic diagram which shows the cross section of one aspect of the mirror surface decorative sheet of this invention. It is a schematic diagram which shows the cross section of one aspect of the mirror surface decorative sheet of this invention. It is a schematic diagram which shows the cross section of one aspect of the mirror surface decorative board of this invention.

[Mirror makeup sheet]
The mirror surface decorative sheet of the present invention has at least a base sheet and a surface protective layer, and the base sheet has a glass transition point (Tg) of −50 to 130 ° C. and a melting point (Tm) of 220 ° C. The surface protective layer is a cured product of the ionizing radiation curable resin composition, and the crack generation elongation measured by a predetermined method of the surface protective layer is 40% or less, The total thickness is 125 μm or more. The mirror surface decorative sheet of the present invention will be described with reference to FIGS.

  1 and 2 are schematic views showing a cross section of one embodiment of the mirror surface decorative sheet of the present invention. A mirror surface decorative sheet 10 shown in FIG. 1 includes a base sheet 1 and a surface protective layer 3. Moreover, the mirror surface decorative sheet shown in FIG. 2 has a base sheet 1, a primer layer 2, a surface protective layer 3, and a masking film 5 in this order, and the side opposite to the side having the surface protective layer of the base sheet ( Hereinafter, the back surface primer layer 4 may be provided.

(Base material sheet)
The substrate sheet is made of a crystalline resin having a glass transition point (Tg) of −50 to 130 ° C. and a melting point (Tm) higher than 220 ° C. If the material constituting the base sheet is a crystalline resin, it has a stable crystal structure as long as it is not higher than the melting point (Tm) even in a temperature region higher than the glass transition temperature (Tg). There is little change, that is, the temperature dependence of flexibility is low. For example, when a decorative sheet is heated (80 to 150 ° C.) while being wrapped on an adherend, uneven application of adhesive (adhesive) or adhesion Without picking up so-called dac, such as unevenness on the body surface, the mirror surface property does not deteriorate after sticking to the adherend, and even if temperature unevenness due to local heating occurs, excellent specularity Can be maintained.

The glass transition point (Tg) of the crystalline resin is required to be −50 to 130 ° C. If the glass transition point (Tg) is lower than −50 ° C., excellent specularity cannot be obtained, and if it exceeds 130 ° C., specularity cannot be obtained or heat resistance cannot be obtained. From the viewpoint of obtaining excellent specularity and heat resistance, the temperature is preferably -20 to 100 ° C, more preferably 0 to 75 ° C.
Here, the glass transition point (Tg) is a value measured according to JIS K7121-1987. Specifically, using the base sheet as a test piece, the test piece is heated from room temperature at a rate of 20 ° C./min, the calorific value is measured with a differential scanning calorimeter (DSC), and an endothermic curve diagram or exotherm. A curve diagram was created, and an extension line was drawn on each of the straight lines before and after the inflection point.

The melting point (Tm) of the crystalline resin needs to be higher than 220 ° C. When the melting point (Tm) is higher than 220 ° C., excellent specularity can be obtained, and in particular, excellent processing characteristics can be obtained when processed into a flat adherend. From the viewpoint of obtaining excellent specularity and processing characteristics, the temperature is preferably 220 to 300 ° C, and more preferably 220 to 280 ° C.
Here, the melting point (Tm) is a value measured in accordance with JIS K7121-1987. Specifically, using the base sheet as a test piece, the test piece was heated from room temperature at a rate of 10 ° C./min, heated to a temperature 30 ° C. higher than the end of the melting peak, held for 10 minutes, and then 10 In the DSC curve obtained by cooling at 40 ° C./min to 40 ° C. and repeating the same heating and cooling again, the temperature at the top of the melting peak was defined as the melting point (Tm). When there are a plurality of endothermic peaks in the DSC curve, the apex temperature of the endothermic peak with the maximum area is adopted.

  As such a crystalline resin, a polyester resin is preferably exemplified. By adopting polyester resin, even if the base sheet is thin, it is difficult to pick up so-called duck such as uneven application of glue (adhesive) or unevenness of the adherend surface, and excellent mirror surface properties can be obtained. Excellent production efficiency can be obtained, and it is also possible to suppress an increase in material costs and transportation costs. Furthermore, surface properties such as excellent weather resistance, stain resistance, scratch resistance, solvent resistance, and heat resistance can be obtained.

  As polyester resin, esterification reaction of aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid as an acid component and aliphatic diol such as ethylene glycol, diethylene glycol, butanediol and hexanediol as an alcohol component The copolymer obtained by (1) is mentioned preferably. Specific examples of the polyester resin used in the present invention include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, ethylene-terephthalate-isophthalate copolymer, and the like. Alternatively, a plurality of types can be used in combination. From the viewpoint of obtaining excellent specularity, polyethylene terephthalate is particularly preferable.

  The thickness of the base sheet is preferably 120 to 545 μm, more preferably 175 to 445 μm, and further preferably 195 to 395 μm. When the thickness of the substrate sheet is within the above range, excellent specularity can be obtained, and the adherend can be concealed when attached to the adherend, resulting in excellent design properties. It is done. Further, the production efficiency is improved, and the increase in material cost and transportation cost can be suppressed.

  The substrate sheet is preferably colored with a colorant. By being colored, the base of an adherend such as a substrate on which a decorative sheet is provided can be concealed, and excellent design properties can be obtained.

Colorants that can be used for the base sheet include carbon black (black), iron black, titanium white, antimony white, yellow lead, titanium yellow, petal, cadmium red, ultramarine, cobalt blue and other inorganic pigments, quinacridone red, Organic pigments such as isoindolinone yellow and phthalocyanine blue, or pearly luster consisting of scaly foils such as dyes, metallic pigments made of scaly foils such as aluminum and brass, titanium dioxide-coated mica, and basic lead carbonate (pearl) ) Pigments are preferred.
The amount of the colorant to be used is not particularly limited as long as it does not lower the film formability and mechanical strength when the substrate sheet is obtained by extrusion molding.

  An additive may be blended in the resin material used for forming the base sheet, if necessary. Examples of the additive include a crystal nucleating agent, a filler, a flame retardant, an antioxidant, a lubricant, a foaming agent, an ultraviolet absorber, and a light stabilizer.

  Among the above additives, from the viewpoint of obtaining excellent specularity, organic crystal nucleating agents such as dibenzylidene sorbitol compounds and phosphate compounds, inorganic crystal nucleating agents such as silica, talc, kaolin and calcium carbide, etc. It is preferable to contain a nucleating agent. Moreover, the glass transition point (Tg) and melting | fusing point (Tm) of a base material sheet can be adjusted by using a nucleating agent, and when the usage-amount of a nucleating agent is increased, a glass transition point (Tg) and melting | fusing point (Tm) will be obtained. Since it tends to be large and heat resistance tends to be obtained, a nucleating agent is used according to the desired performance, and the amount used may be appropriately determined.

  Moreover, it is preferable to contain inorganic fillers, such as calcium carbonate, barium sulfate, clay, and talc, from the viewpoint of obtaining excellent processing characteristics. The content of these inorganic fillers is preferably in the range of 1 to 60% by mass with respect to the substrate 2.

  The base sheet may have a single-layer structure using the above-mentioned materials, or may have a structure in which a plurality of layers are integrated by, for example, a T-die extrusion method. For example, preferably, a surface layer and a back layer forming material including a polyester resin, a nucleating agent, and other additives, and an intermediate layer forming material including a polyester resin, a coloring agent, a nucleating agent, and other additives are prepared. After mixing each of these materials, the temperature of the extruder is set at 230 to 280 ° C., the temperature setting of the feed block part is set to about 240 ° C., and the surface layer / intermediate layer / back layer is formed by the T-die extrusion method. A base sheet composed of a polyester resin having three layers can be obtained.

(Surface protective layer)
The surface protective layer is an ionizing radiation curable resin that imparts surface characteristics such as weather resistance, stain resistance, scratch resistance, solvent resistance, and heat resistance to the decorative sheet of the present invention, and also provides excellent specularity. It is a layer composed of a cured product of the composition and having a crack generation elongation measured by the following method of 40% or less.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127 was prepared as a decorative sheet, and the test piece was measured at a tensile speed of 20 mm / min, a distance between chucks of 80 mm, and a width of 25 mm using a tensile tester in a temperature environment of 70 ° C. After pulling at an arbitrary elongation under certain conditions, the inside of the chuck is colored with a whiteboard marker, and the colored part is wiped off with a cloth. It was set as the elongation.

  The surface protective layer is composed of a cured product of an ionizing radiation curable resin composition containing an ionizing radiation curable resin. Here, the ionizing radiation curable resin composition is a resin composition that is cured by irradiating with ionizing radiation, and the ionizing radiation has an energy quantum capable of polymerizing or crosslinking molecules among electromagnetic waves or charged particle beams. In addition to ultraviolet rays (UV) or electron beams (EB), electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion rays are also used.

The ionizing radiation curable resin contained in the ionizing radiation curable resin composition is appropriately selected from polymerizable monomers and polymerizable oligomers (or prepolymers) conventionally used as ionizing radiation curable resins. be able to.
For example, polymerizable monomers such as monofunctional (meth) acrylate and polyfunctional (meth) acrylate, urethane (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, polyester (meth) acrylate oligomer, polyether (meth) acrylate oligomer Polymerizable oligomers such as acrylic (meth) acrylate oligomers, or prepolymers can be used alone or in combination of two or more.

  In the present invention, a polymerizable oligomer is preferably used as the ionizing radiation curable resin, a polyfunctional polymerizable oligomer having 2 or more functional groups is preferable, and a polyfunctional polymerizable oligomer having 3 or more functional groups is more preferable. As the number of functional groups increases, the crack generation elongation decreases, and as the number of functional groups decreases, the crack generation elongation tends to increase. Therefore, two types of oligomers having different functional group numbers depending on the desired crack generation elongation Or a kind of oligomer may be appropriately selected and used.

When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the resin. The initiator for photopolymerization can be appropriately selected from those conventionally used, and is not particularly limited. For example, the initiator for photopolymerization such as benzoin, acetophenone, phenylketone, benzophenone, and anthraquinone An agent is preferably mentioned.
Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.

  The ionizing radiation curable resin used in the present invention is preferably an electron beam curable resin. In the case of an electron beam curable resin, solvent-free is possible, which is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, provides stable curing characteristics, and excellent surface characteristics. This is because

  In the ionizing radiation curable resin composition, various additives such as a filler (filler) such as an abrasion resistant filler, a mat forming filler, and a flaw resistant filler, or an ultraviolet absorber (UVA) or a hindered amine for improving weather resistance. A weathering agent such as a light stabilizer (HALS) can be contained. These weathering agents are reactive ultraviolet absorbers having reactive functional groups having ethylenic double bonds such as (meth) acryloyl groups, vinyl groups, and allyl groups, or reactive light stabilizers (HALS). It is preferable from the point that stable weather resistance can be obtained without causing bleeding out of the weathering agent.

  In addition, ionizing radiation curable resin compositions are used as various additive components for the purpose of improving the concealability of the surface protective layer in the resulting decorative sheet, preventing yellowing of the base material, and improving light resistance. Inorganic color pigments such as paste and carbon black can be appropriately added.

  The surface protective layer needs to have a crack generation elongation of 40% or less measured by the above-described predetermined method. When the crack generation elongation exceeds 40%, the surface protective layer becomes too soft, the scratch resistance is lowered, and excellent surface characteristics cannot be obtained. In the present invention, the crack generation elongation is preferably as small as possible since excellent scratch resistance is obtained, and there is no limit to the lower limit, but from the viewpoint of obtaining excellent processing characteristics without generating cracks in the surface protective layer, 1% The above is preferable, and 3% or more is more preferable.

  The thickness of the surface protective layer is preferably 5 to 20 μm, and more preferably 7 to 17 μm. If the thickness of the surface protective layer is 5 μm or more, excellent specularity and surface characteristics can be obtained, and if it is 20 μm or less, excellent processing characteristics can be obtained.

(Primer layer)
The primer layer is provided between the base sheet and the surface protective layer, and is a layer that is preferably provided in order to improve the adhesion of these layers and to improve the specularity.
The resin material (binder resin) constituting the primer layer is not particularly limited, and examples thereof include urethane resins, acrylic resins, polyester resins, vinyl chloride / vinyl acetate copolymers, chlorinated polypropylene resins, and chlorinated polyethylene resins. Preferably mentioned. In addition, a two-part curable resin is preferable from the viewpoint of obtaining excellent adhesion and specularity.
The two-component curable resin is not particularly limited as long as it is a resin that is cured by adding a curing agent to the main agent. Two-component curing in which the main agent is a polyol (polyhydric alcohol) and the curing agent is an isocyanate curing agent. A urethane resin is preferable.

  Examples of the main agent include, for example, polyols such as polyethylene glycol, polypropylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol, (meth) acrylic acid esters such as methyl (meth) acrylate, and (meth) Acrylic polyols obtained by addition polymerization with monomers having a hydroxyl group such as 2-hydroxyethyl acrylate and 2-hydroxypropyl (meth) acrylate; known diols such as glycols such as ethylene glycol and propylene glycol and adipine Polyester polyols obtained by polycondensation reaction with at least one selected from dibasic acids such as acid, maleic acid, phthalic acid and terephthalic acid, and acid esters thereof; the above diols and ethylene oxide Id, propylene oxide, polyol having a hydroxyl group as a functional group, such as polyether polyols obtained by addition polymerization of such as tetrahydrofuran and the like preferably. These can be used individually or in mixture of multiple types.

  As the isocyanate curing agent, a conventionally known compound may be appropriately used. For example, aromatic compounds such as 2,4-tolylene diisocyanate (TDI), xylene diisocyanate (XDI), naphthalene diisocyanate, and 4,4′-diphenylmethane diisocyanate. Isocyanate or poly (such as aliphatic (or cycloaliphatic) isocyanate such as 1,6-hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate Isocyanates are used. Further, adducts or multimers of these various isocyanates, for example, adducts of tolylene diisocyanate, tolylene diisocyanate trimers and the like are also used.

  In order to improve the specularity, the primer layer preferably contains a matting agent. Preferred examples of the matting agent include inorganic particles such as alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide, and organic particles such as acrylic resin, urethane resin, nylon resin, polypropylene resin, and urea resin. Any one type may be used, or two or more types may be used in combination.

Examples of the shape of the matting agent include a sphere, an ellipsoid, a polyhedron, a scale shape, and the like. Although there is no particular limitation, a spherical shape is preferable in terms of obtaining specularity.
The average particle size of the matting agent is preferably 0.5 to 8 μm, and more preferably 1 to 5 μm. When the average particle diameter is within the above range, excellent specularity can be obtained. Here, the average particle size is a volume-based particle size measured by laser diffraction type or laser scattering type particle size distribution measurement.

  The content of the matting agent is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and further preferably 3 to 10 parts by mass with respect to 100 parts by mass of the binder resin. preferable. When the content is within the above range, excellent adhesion and specularity can be obtained.

  The thickness of a primer layer is about 0.5-20 micrometers normally, and 1-10 micrometers is preferable. When the thickness of the primer layer is within the above range, excellent adhesion and specularity can be obtained.

(Back primer layer)
The back surface primer layer is a layer preferably provided for the purpose of improving the adhesion between the base sheet and various adherends, for example, the substrate shown in FIG. It is provided on the opposite surface.
Preferred examples of the resin material (binder resin) for forming the back primer layer include those described as the resin material (binder resin) for forming the primer layer described above, and are appropriately selected depending on the material of the adherend. The

  Moreover, it is preferable that a back surface primer layer also contains a mat agent similarly to said primer layer. Preferred examples of the matting agent include those described as matting agents used for forming the primer layer, and the average molecular weight and content thereof are the same as described above.

  The thickness of the back primer layer is preferably about 1 to 5 μm, more preferably 1 to 3 μm. When the thickness is within the above range, excellent adhesion between the substrate sheet and various adherends can be obtained.

(Decoration layer)
The decorative layer gives decorativeness to the mirror surface decorative sheet, and may be a uniformly colored concealing layer (solid printing layer), or by printing various patterns using ink and a printing machine. The pattern layer to be formed may be used, or a combination of a concealing layer and a pattern layer may be used. A decoration layer is normally provided between a base material sheet and a surface protective layer, or between a base material sheet and the primer layer preferably provided.

By providing a concealing layer, the surface of the adherend can be concealed, and when the base sheet is colored or uneven in color, the surface color can be adjusted by giving the intended color. .
In addition, by providing a pattern layer, a grain pattern imitating the surface of a rock such as a wood grain pattern, marble pattern (for example, travertine marble pattern), a fabric pattern imitating a texture or cloth pattern, tiled pattern, brickwork A pattern such as a pattern or a combination of these, a parquet, a patchwork, or the like can be applied to the decorative sheet. These patterns are formed by multicolor printing with the usual yellow, red, blue and black process colors, as well as by multicolor printing with special colors prepared by preparing the individual color plates constituting the pattern. Is done.

As the ink composition used for the decorative layer, a binder resin in which a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, or a curing agent is appropriately mixed is used. The binder resin is not particularly limited. For example, urethane resin, vinyl chloride / vinyl acetate copolymer resin, vinyl chloride / vinyl acetate / acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, polyester resin, polyamide resin. , Butyral resin, polystyrene resin, nitrocellulose resin, cellulose acetate resin and the like are preferable, and polyurethane resin is more preferable. Any of these binder resins can be used alone or in admixture of two or more.
Moreover, as a coloring agent, what was illustrated as a coloring agent used for a base material sheet is mentioned preferably.

  The thickness of the decoration layer is usually about 0.5 to 20 μm, and preferably 1 to 10 μm. If the thickness of the decoration layer is within the above range, it is possible to impart excellent design properties to the decorative sheet and to impart concealability.

(Masking film)
The masking film is used to protect the surface of the mirror-finished decorative sheet from scratches when transporting and applying the decorative board obtained by processing, including when the mirror-finished decorative sheet is processed on an adherend. It is a film preferably provided on the top.

The masking film usually has a structure having a masking film substrate and an adhesive layer.
As a base material for masking films, polyester films, such as a polyethylene terephthalate (PET) film, polyolefin films, such as a polyethylene film and a polypropylene film, a polycarbonate film, etc. are mentioned preferably.

  Although there is no restriction | limiting in particular about the thickness of this base material for masking films, It is preferable that it is 10-100 micrometers, and it is more preferable that it is 30-70 micrometers. When the thickness is within the above range, good scratch resistance can be obtained, turning and peeling are unlikely to occur during processing, and cost can be reduced.

The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is, for example, an acrylic-based polymer mainly composed of a (meth) acrylic acid ester-based polymer, from the viewpoint of being difficult to peel off during storage, easy to peel off during use, and difficult to leave a pressure-sensitive adhesive residue. In addition to the pressure-sensitive adhesive, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and the like are preferable.
Moreover, 1-20 micrometers is preferable and, as for the thickness of an adhesive layer, 3-10 micrometers is more preferable. When the thickness is within the above range, it is difficult to peel off during storage, it is easy to peel off during use, and the adhesive remains difficult to leave.

(Characteristics and performance of mirror surface decorative sheet)
The thickness of the mirror surface decorative sheet of the present invention is required to be 125 μm or more. If the thickness is less than 125 μm, it becomes easy to pick up so-called duck such as uneven application of glue (adhesive) or irregularities on the surface of the adherend, and excellent specularity cannot be obtained, and concealment is obtained. Since there is no design, designability falls.
The thickness of the mirror surface decorative sheet is preferably 125 to 550 μm, more preferably 180 to 450 μm, and further preferably 200 to 400 μm. When the thickness is within the above range, excellent specularity and processing characteristics can be obtained, production efficiency can be improved, and cost increases in material costs and transportation costs can be suppressed.

Moreover, the mirror surface decorative sheet of the present invention is a sheet having a color difference (ΔE) of less than 1.2 and further less than 0.5 in the following evaluation. The mirror surface decorative sheet of the present invention has such a color difference, is excellent in concealment properties, and is not easily affected by the substrate, so that excellent mirror surface properties can be obtained. Here, the color difference (ΔE) is obtained by taking a test piece from the center part of the mirror surface decorative sheet and using the black background of the concealment rate test paper (JIS K5400 7.2 (2) (f)) as the background and the white background as the background. In two points, the CIE (International Commission on Illumination) L * a * b * color system defined in JIS Z 8729-1994 represents L *, a *, and b * as D65 light source and 10 degrees. ΔE measured using a spectrocolorimeter under visual field conditions, and the difference between L *, a *, and b * at the two points was ΔL *, Δa *, and Δb *, respectively, and calculated using the following formula: It is. A lower ΔE value indicates higher concealment and better specularity.
Color difference ΔE = ((ΔL *) ² + (Δa *) ² + (Δb *) ² ) ^1/2

(Manufacturing method of mirror surface decorative sheet)
The mirror surface decorative sheet of the present invention comprises a step (1) a step of forming a base material sheet, a step (3) an ionizing radiation curable resin composition is applied on the base material sheet, crosslinked and cured, and a surface protective layer is formed. Steps to be formed are sequentially passed, or preferably, step (1) a step of forming a base sheet, step (2) a step of forming a primer layer and / or a back primer layer on the base sheet, (3) the primer It can be manufactured by applying an ionizing radiation curable resin composition on the layer, followed by a step of forming a surface protective layer by crosslinking and curing.

Step (1) is a step of forming a base sheet.
The base sheet is obtained by forming a resin composition in which a colorant and other additives are added to a resin material as desired by a method such as a calendering method, an inflation method, or a T-die extrusion method. Here, biaxial stretching may be performed as necessary.

  Further, when the base sheet has a multi-layer structure such as a two-layer structure or a three-layer structure as described above, for example, preferably, a surface layer and a back surface containing a homopolypropylene resin, a random polypropylene resin, a nucleating agent, and other additives. Prepare layer forming material, homopolypropylene resin, random polypropylene resin, colorant, nucleating agent, and other additives, and mix these materials. A base sheet composed of a polypropylene resin having three layers of surface layer / intermediate layer / back layer is obtained by T-die extrusion method with a temperature setting of 180 to 230 ° C. and a temperature setting of the feed block portion being 210 ° C. Can do.

  From the viewpoint of improving the adhesion with the layer in contact with the obtained substrate sheet, the surface may optionally be subjected to an oxidation method such as corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone-ultraviolet treatment method, An easy-adhesion layer may be provided by performing physical or chemical surface treatment such as a sand blasting method or a roughening method such as a solvent processing method.

  Step (2) is a step of forming a primer layer and / or a back primer layer on the substrate sheet, and is a preferable step. The primer layer and the back primer layer form these layers, for example, a resin composition containing a binder resin and a matting agent, gravure printing method, bar coating method, roll coating method, reverse roll coating method, comma coating method, etc. What is necessary is just to apply | coat and form with the well-known coating method of these. Moreover, when providing both a primer layer and a back surface primer layer, you may form any layer previously.

  Step (3) is a step of forming a surface protective layer by applying an ionizing radiation curable resin composition on a base material sheet or a primer layer preferably provided on the base material sheet, followed by crosslinking and curing.

  The application of the ionizing radiation curable resin composition is a gravure printing method on the surface of the base sheet or the primer layer provided as desired, preferably with a thickness after curing of 5 to 20 μm. , A known method such as a bar coating method, a roll coating method, a reverse roll coating method or a comma coating method, preferably a gravure printing method. The viscosity of the ionizing radiation curable resin composition is not particularly limited as long as it is a viscosity capable of forming an uncured resin layer of the ionizing radiation curable resin composition on the surface of the base sheet or primer layer.

Next, the uncured resin layer formed by applying the ionizing radiation curable resin composition is irradiated with ionizing radiation such as an electron beam and ultraviolet rays to cure the uncured resin layer, and the ionizing radiation curable resin composition A surface protective layer which is a cured product of is formed.
When an electron beam is used as the ionizing radiation, the accelerating voltage can be appropriately selected according to the resin used and the thickness of the layer, but it is preferable to cure the uncured resin layer usually at an accelerating voltage of about 70 to 300 kV.

In electron beam irradiation, transmission capability increases as the acceleration voltage increases. Therefore, when using a material that deteriorates due to electron beams as the base layer, the transmission depth of the electron beam and the thickness of the resin layer are substantially equal. By selecting the accelerating voltage so as to be equal, it is possible to suppress the irradiation of the extra electron beam to the base material sheet, and it is possible to minimize the deterioration of the base material layer due to the excess electron beam.
The irradiation dose is preferably such that the crosslinking density of the resin layer is saturated, usually 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 100 kGy (1 to 10 Mrad), more preferably 30 to 70 kGy (3 to 7 Mrad). It is selected in the range.
The electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

  When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used.

  The mirror surface decorative sheet of the present invention obtained in this way has excellent specularity and design, and has excellent processing characteristics that do not cause springback and cracks during processing, and excellent surface characteristics. . Taking advantage of this feature, the mirror surface decorative sheet of the present invention is bonded to an adherend such as a substrate as a mirror surface decorative plate, and is used for various members such as interior and exterior of buildings, building materials, furniture, or household appliances, especially kitchens. It is suitably used for decorative plates used for interior materials such as product kitchens and bathroom storage and doors.

[Mirror face panel]
The mirror surface decorative sheet of the present invention has a substrate, an adhesive layer, and the mirror surface decorative sheet of the present invention in this order. The decorative board of the present invention will be described with reference to FIG.

FIG. 3 is a schematic view showing a cross section of a preferred embodiment of the mirror surface decorative board of the present invention. The mirror surface decorative plate 20 shown in FIG. 3 has a substrate 21, an adhesive layer 22, and a mirror surface decorative sheet 10 in this order.
The substrate used in the mirror surface decorative plate of the present invention is not particularly limited, and a wood-based board such as wood, a plastic film or a plastic sheet, a metal plate, a ceramic material, etc. can be appropriately selected according to the application. .

  Examples of wood-based boards include veneer of various materials such as cedar, firewood, firewood, pine, lawan, teak, and merapie, and wood materials such as wood veneer, wood plywood, particle board, and medium density fiberboard (MDF). It is done. These can be used alone or in a laminated manner. The wooden board includes not only a wooden board but also a plastic board containing paper powder and reinforced paper having strength.

As a plastic film and a plastic sheet, what consists of various synthetic resins is mentioned. Examples of the synthetic resin include polyolefin resin, vinyl resin, polyester resin, acrylic resin, polyamide resin, cellulose resin, polystyrene resin, polycarbonate resin, polyarylate resin, and polyimide resin.
Moreover, when using a plastic film or a plastic sheet as a substrate, in order to improve the adhesion with the decorative sheet, if desired, on one or both sides, corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, A physical or chemical surface treatment such as an oxidation method such as an ozone-ultraviolet treatment method or an unevenness method such as a sand blast method or a solvent treatment method can be performed.

  Examples of the metal plate include metal materials such as iron, aluminum, stainless steel, and copper, and these may be subjected to surface treatment such as hot dip galvanizing or electrogalvanizing. In addition, in order to impart concealability, the metal plate may be directly colored and provided with a coating layer.

  Examples of ceramic materials include ceramic building materials such as gypsum plates, calcium silicate plates, and wood cement plates, ceramics, glass, firewood, fired tiles, plates made mainly of volcanic ash, and the like. In addition to these, composites of various materials such as a fiber reinforced plastic (FRP) plate, an iron plate attached to both sides of a paper honeycomb, and a polyethylene resin sandwiched between two aluminum plates can also be used as a substrate.

  It does not specifically limit as an adhesive agent used for the contact bonding layer for adhere | attaching a board | substrate and a mirror surface decorative sheet, A heat sensitive adhesive, a pressure sensitive adhesive, etc. are mentioned. Examples of the resin used for the adhesive constituting this adhesive layer include acrylic resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, styrene-acryl copolymer resins, At least one resin selected from polyester resins and polyamide resins is used. Further, a two-component curable polyurethane adhesive or polyester adhesive using isocyanate as a curing agent can also be applied.

  A reactive hot melt adhesive is also preferably used. The reactive hot melt adhesive is solid at room temperature, and is used by being applied to a substrate or a mirror surface decorative sheet while being heated and melted. A typical example of such a reactive hot melt adhesive is a urethane-based reactive hot melt (hereinafter referred to as “PUR”). This PUR contains a functional group (isocyanate group) that reacts with moisture in the components, and reacts with moisture attached to the substrate and the decorative sheet and moisture given through them after cooling and curing. After the reaction, it does not melt even when heated and has a high adhesive strength.

  An adhesive can also be used for the adhesive layer. As the pressure-sensitive adhesive, an acrylic, urethane, silicone, rubber or the like can be appropriately selected and used.

  Among these, as the adhesive used for the adhesive layer, the thermoplastic resin adhesive and the reactive hot melt adhesive function as a cushion layer. For example, under severe conditions when a metal plate is used as the substrate. This is preferable because it has an effect of suppressing cracks in the surface protective layer during processing.

The adhesive layer is formed by applying and drying the above resin in a form that can be applied, such as a solution or emulsion, by means of gravure printing, screen printing, or reverse coating using a gravure plate. Can do.
Although there is no restriction | limiting in particular in the thickness of an contact bonding layer, Usually, it is the range of 1-100 micrometers. By setting it as this range, the outstanding adhesiveness and the suppression effect of the crack generation of a surface protective layer are acquired.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

(Evaluation method)
1. Evaluation of specularity (visual evaluation)
About the decorative sheet and the decorative plate obtained in the examples and comparative examples, the fluorescent lamp is placed on the surface of the decorative sheet under a three-wavelength light emitting fluorescent lamp (“FPL27EX-N (model number)”, manufactured by Panasonic Corporation). The image reflected in the image was visually confirmed and evaluated according to the following criteria.
○: The image of the fluorescent lamp was clearly visible.
Δ: Slight undulation of fluorescent lamp image appears, but there was no practical problem.
X: A fluorescent lamp image was struck and roughened.
XX: The image of the fluorescent lamp was wavy and the roughness was remarkable.
2. Evaluation of processing characteristics Polyurethane hot melt adhesive ("Hibon 4836 (product number)"), Hitachi Chemical, melted at a temperature of 115 ° C using a melting device ("MC-12 (model number)", manufactured by Nordson Co., Ltd.) Polymer (manufactured by Co., Ltd.) was applied to a flat plate-shaped MDF (thickness 3 mm, conforming to JIS A5905: 2003) so as to have a thickness of 80 μm to form an adhesive layer. Subsequently, the base material and MDF of the decorative sheet obtained in Examples and Comparative Examples were bonded through the adhesive layer. The finished state such as peeling of the decorative sheet and occurrence of cracks was visually observed and evaluated according to the following criteria.
○: Peeling and cracks were hardly confirmed.
X: Minor peeling and / or cracks were confirmed.
XX: Significant peeling and / or cracking was confirmed.
3. Evaluation of scratch resistance Steel wool (# 0000) was attached to a weight adjusted so that the load of 29.4 KPa (300 g / cm 2) was applied to the decorative sheets obtained in Examples and Comparative Examples, and makeup was made with the steel wool. The sheet was rubbed 50 times, and the change in gloss on the surface of the decorative sheet was visually observed and evaluated according to the following criteria.
A: Almost no change in appearance was confirmed.
○: A slight change in appearance was confirmed, but there was no practical problem.
○ Δ: Appearance change between ○ and Δ was confirmed, but there was no practical problem.
Δ: Although a change in appearance was confirmed, there was no practical problem.
X: A remarkable change in appearance was confirmed.
4). Evaluation of heat resistance (dry heat test)
The aluminum sheet (diameter: 10 cm cylindrical shape, weight: 700 g) heated to 75 ° C. was placed on the decorative sheets obtained in the examples and comparative examples and left for 20 minutes, and then the place where the jig was placed was placed. The change in appearance gloss and the occurrence of thermal wrinkles were visually observed and evaluated according to the following criteria.
○: Almost no change in appearance (glossy unevenness or heat wrinkles) was observed.
X: Change in appearance (gloss unevenness and heat wrinkles) was confirmed.
5. Evaluation of concealment For the decorative sheets obtained in the examples and comparative examples, the black background of the concealment rate test paper (JIS K5400 7.2 (2) (f)) and the white background In two respects, L *, a *, and b * in the CIE (International Lighting Commission) L * a * b * color system defined in JIS Z 8729-1994 are spectroscopically analyzed with a D65 light source and a viewing condition of 10 degrees. It is ΔE calculated using the following equation, measured using a colorimeter, and the difference between L *, a *, and b * at the two points is ΔL *, Δa *, and Δb *, respectively. A lower ΔE value indicates higher concealment and better specularity.
Color difference ΔE = ((ΔL *) ² + (Δa *) ² + (Δb *) ² ) ^1/2
○: Color difference ΔE was less than 0.5.
Δ: Color difference ΔE was 0.5 or more and less than 1.2.
X: The color difference ΔE was 1.2 or more.

Example 1
A colored polyethylene terephthalate resin sheet (thickness: 150 μm, “Lumirror E20 (trade name)”, manufactured by Toray Industries, Inc.) is used as a base sheet, and a polyester resin composition (two-component thermosetting resin type, A primer composition (thickness: 2 μm) is formed by applying a matting agent having an average particle diameter of 4 μm to 6 parts by mass with respect to 100 parts by mass of the resin component. Polyester is formed on the other surface. -A urethane resin composition was applied to form a back primer layer (thickness: 2 µm).
Next, an ionizing radiation curable resin composition (urethane acrylate oligomer (functional group number: 3)) was applied on the primer layer at a coating amount of 10 g / m ² by gravure printing to form a coating film. Next, the coating film was crosslinked and cured by irradiation with an electron beam under the conditions of 175 keV and 5 Mrad (50 kGy) to form a surface protective layer (thickness: 10 μm) to obtain a mirror-finished decorative sheet. The thickness of the obtained mirror surface decorative sheet was 164 μm, and the crack generation elongation of the surface protective layer was 15%.
Further, a polyethylene film (thickness: 50 μm) having an adhesive layer (acrylic resin adhesive, thickness: 5 μm) on the surface protective layer side is masked so that the surface protective layer and the adhesive layer face each other. Films were laminated.
Then, an ethylene-vinyl acetate adhesive (water-based emulsion type, “BA-20 (trade name)”, manufactured by Chuo Rika Co., Ltd.) was applied to the surface of the mirror-finished decorative sheet on the back primer layer side, and the adhesive layer (Thickness: 70 μm) was formed and adhered to a medium density wood fiber board (MDF, thickness: 18 mm) to obtain a mirror-finished decorative board.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Example 2
In Example 1, a specular decorative sheet and a specular decorative sheet were obtained in the same manner as in Example 1 except that the thickness of the base sheet was 250 μm and the total thickness was 264 μm. The crack generation elongation of the surface protective layer of the obtained mirror surface decorative sheet was 15%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Example 3
In Example 1, a specular decorative sheet and a specular decorative sheet were obtained in the same manner as in Example 1 except that the thickness of the base sheet was 500 μm and the total thickness was 514 μm. The crack generation elongation of the surface protective layer of the obtained mirror surface decorative sheet was 15%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Example 4
In Example 1, 80 mass parts of urethane acrylate oligomer (functional group number: 3), urethane acrylate oligomer (functional group number: 3) and urethane acrylate oligomer (functional group number: 3) in the ionizing radiation curable resin forming the surface protective layer. A mirror surface decorative sheet and a mirror surface decorative plate were obtained in the same manner as in Example 1 except that 2) was changed to a mixture of 20 parts by mass. The crack generation elongation of the surface protective layer of the obtained mirror surface decorative sheet was 30%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Example 5
The same procedure as in Example 1 was conducted except that the urethane acrylate oligomer (functional group number: 3) in the ionizing radiation curable resin forming the surface protective layer was changed to a urethane acrylate oligomer (functional group number: 6). Thus, a specular decorative sheet and a specular decorative sheet were obtained. The crack generation elongation of the surface protective layer of the obtained mirror surface decorative sheet was 30%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Examples 6 and 7
In Example 2, a specular decorative sheet and a specular decorative sheet were obtained in the same manner as in Example 2 except that the resin material constituting the base sheet was changed to that shown in Table 1. The crack generation elongation of the surface protective layer of the obtained mirror surface decorative sheet was 15%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 1.

Comparative Example 1
In Example 1, a decorative sheet and a decorative board were obtained in the same manner as in Example 1, except that the thickness of the base sheet was 86 μm and the total thickness was 100 μm. The crack generation elongation of the surface protective layer of the obtained decorative sheet was 15%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 2.

Comparative Example 2
In Example 1, the urethane acrylate oligomer (functional group number: 3) in the ionizing radiation curable resin forming the surface protective layer was mixed with 50 parts by mass of the urethane acrylate oligomer (functional group number: 3) and a thermoplastic resin (acrylic resin). , Weight average molecular weight: 2 to 30,000) A decorative sheet and a decorative board were obtained in the same manner as in Example 1 except that the mixture was changed to 50 parts by mass. The crack generation elongation of the surface protective layer of the obtained decorative sheet was 50%.
Said evaluation was performed about the obtained decorative sheet and decorative board. The evaluation results are shown in Table 2.

* 1, PET: Polyethylene terephthalate resin sheet (colored PET resin sheet, “Lumirror E20 (trade name)”, manufactured by Toray Industries, Inc.)
PBT: Polybutylene terephthalate resin sheet ("OK01WW (trade name)", manufactured by Okura Industry Co., Ltd.)
PEN: Polyethylene naphthalate resin sheet ("Teonex (trade name)", manufactured by Teijin DuPont Films Ltd.)

* 1, PET: Polyethylene terephthalate resin sheet (colored PET resin sheet, “Lumirror E20 (trade name)”, manufactured by Toray Industries, Inc.)

It was confirmed that the decorative sheet and the decorative board of the present invention show good results in all evaluation items.
Although the same PET resin sheet as in Example 1 was used as the base sheet, in Comparative Example 1 in which the total thickness was thin, concealability was not obtained and good results were not obtained in terms of design. Moreover, although the same polypropylene resin sheet as Example 1 was used as a base material sheet, the comparative example 2 with a crack growth elongation as large as 50% did not give a good result in terms of scratch resistance.
From the results of these Examples and Comparative Examples, the decorative sheet and decorative board of the present invention have excellent mirror surface and design properties, and balance excellent processing characteristics that do not cause cracks during processing and excellent surface properties. It was confirmed that it had well.

  The mirror surface decorative sheet of the present invention is bonded to a substrate such as a metal plate, an inorganic plate (gypsum board, etc.), a wooden plate (MDF, particle board, laminated plate, etc.) as a mirror surface decorative plate, as an interior and exterior of a building, a building material, It is suitably used for various members such as furniture or household appliances, interior materials such as kitchen and bathroom storage and doors of kitchen products, especially flat-plate members.

1. 1. Base sheet 2. Primer layer 3. 3. Surface protective layer 4. Back primer layer Masking film10. Mirror surface decorative sheet 20. Mirror surface decorative board 21. Substrate 22. Adhesive layer

Claims (7)

It has at least a base sheet and a surface protective layer, and the base sheet is made of a crystalline resin having a glass transition point (Tg) of −50 to 130 ° C. and a melting point (Tm) higher than 220 ° C. The surface protective layer is a cured product of an ionizing radiation curable resin composition, the crack generation elongation of the surface protective layer measured by the following method is 40% or less, and the total thickness is 125 μm or more. Mirror surface decorative sheet.
(Measurement of crack elongation)
A strip-shaped test piece according to JIS K7127 was prepared as a decorative sheet, and the test piece was measured at a tensile speed of 20 mm / min, a distance between chucks of 80 mm, and a width of 25 mm using a tensile tester in a temperature environment of 70 ° C. After pulling at an arbitrary elongation under certain conditions, the inside of the chuck is colored with a whiteboard marker, and the colored part is wiped off with a cloth. It was set as the elongation.   The mirror surface decorative sheet according to claim 1, wherein the crystalline resin is a polyester resin.   The mirror surface decorative sheet according to claim 1 or 2, wherein the thickness of the surface protective layer is 5 to 20 µm.   The specular decorative sheet according to any one of claims 1 to 3, wherein the ionizing radiation curable resin contained in the ionizing radiation curable resin composition is an electron beam curable resin.   The mirror surface according to any one of claims 1 to 4, which has a primer layer between the base sheet and the surface protective layer, and has a back primer layer on the side opposite to the side having the surface protective layer of the base sheet. Makeup sheet.   The mirror surface decorative sheet according to any one of claims 1 to 5, further comprising a masking film on the surface protective layer.   The mirror surface decorative board which has a board | substrate, an adhesive layer, and the mirror surface decorative sheet in any one of Claims 1-6 in order.