JP2010228179A - Decorative sheet and decorative board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet having surface durability close to a melamine decorative board, and bendability, machinability, and designability at least equivalent to those of an adhesive soft PVC decorative sheet. <P>SOLUTION: The decorative sheet comprises a hard coat layer, a design layer having a biaxial stretching polyester film as a support body, and acrylic emulsion-based adhesive layer in the order from the surface. Wood grain patterns and abstract patterns are printed on the back surface of the biaxial stretching polyester film in gravure printing and the film has a thickness of 20-200 μm. The thickness of the adhesive layer is 15-150 μm. The decorative board is obtained by laminating the decorative sheet on a base material, for example, a metal plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a decorative sheet and a decorative board.

  Conventionally, to cover the surface of base materials such as particle board, plywood, MDF, metal plate, etc. used for materials such as top plates, counters, wall panels, etc., to improve design and durability (for example, wood grain pattern, etc.) ), Melamine decorative boards, adhesive soft PVC (polyvinyl chloride) decorative sheets, and olefin resin decorative sheets are known.

  Melamine decorative boards have high surface hardness and durability such as heat resistance, contamination resistance, and solvent resistance. Therefore, they are used for horizontal surfaces such as top plates and counters. Adhesive soft PVC decorative sheets do not require application of adhesive, are flexible and can be bonded to various curved surfaces, and are mainly used for vertical surfaces that do not require high durability.

Olefin resin decorative sheet is inferior in processability to soft PVC decorative sheet, but it is used as an environmentally friendly decorative board because it does not generate hydrogen chloride that damages the incinerator during incineration and there is no possibility of generating harmful dioxins. Yes.
JP 2003-266591 A

  However, the adhesive soft PVC decorative sheet has a soft surface and is easily scratched and easily broken. If the sheet is easy to stretch and there is a foreign substance when it is bonded to the substrate, defects are likely to appear on the film surface. Since it dissolves in organic solvents such as thinner, scribbling with oily markers cannot be wiped off with organic solvents such as thinner. There is a case where a dimensional change due to a temperature change is large and a gap is generated. Thaw with wiping out tobacco.

  Due to the characteristics of the resin, the plasticizer contained in the base sheet may move to the adhesive layer, other plastic materials that are in contact, etc., and as a result, the adhesive strength may be reduced or contact points with other plastic materials may be present. There are cases where it adheres and becomes contaminated. Although it is flexible, when it is rapidly bent at room temperature 2R (R; bending radius “mm”) after being bonded to a metal plate, the bent portion is stretched and “whitening”, “pattern cut”, “break” There was a drawback. In addition, it has been pointed out that hydrogen chloride is generated during incineration and damages the incinerator, possibly generating harmful dioxins.

  Since the surface of the olefin resin decorative sheet is soft, it is easily scratched and easily broken. If the sheet is easy to stretch and there is a foreign substance when it is bonded to the substrate, defects are likely to appear on the film surface. Compared with the soft PVC decorative sheet, there was a defect that it was easily “whitened” and “pattern cut” by bending.

  On the other hand, in the case of a melamine decorative board, the surface durability is excellent, but since it is hard and brittle, bending like the above-mentioned adhesive soft PVC decorative sheet with adhesive is impossible because the decorative board breaks. Since the dimensional change due to moisture absorption and drying is large, peeling due to sticking occurs with time, and thus sticking with a strong adhesive such as a synthetic rubber, vinyl acetate, or urea is necessary. Furthermore, the surface transparent layer is thin and lacks transparency in terms of design. There is a problem in that the color tone of the cut edge portion and the surface flat portion is different, resulting in lack of design.

  The present invention has been studied in view of such circumstances, and the present invention has a surface durability close to that of a melamine decorative board, and has a bendability, workability, and designability equivalent to or higher than those of a soft PVC decorative sheet with an adhesive. A decorative sheet comprising a hard coat layer, a design layer having a plastic film as a support, and an adhesive layer in order from the surface.

  The decorative sheet of the present invention has a hard surface and is difficult to be scratched and torn. The sheet is difficult to stretch, and defects are less likely to appear on the film surface when bonded to an uneven substrate. Since it is difficult to dissolve in an organic solvent such as thinner, graffiti from an oily marker can be wiped off with an organic solvent such as thinner. Small dimensional change due to temperature change and humidity change, making it difficult for gaps and cracks to occur. There is no significant change in the wiping out of cigarettes.

  Does not contain plasticizers such as phthalates, and does not cause contamination due to migration of plasticizers or decrease in adhesive strength. When bonded to a metal plate and then rapidly bent at room temperature 2R (R; bending radius “mm”), it is difficult to “brighten”, “pattern break”, or “break” because the bent portion is difficult to stretch.

  Also, there is no generation of hydrogen chloride or harmful dioxins during incineration. Furthermore, a design with a sense of depth due to the thickness of the plastic film can be obtained. Since the color tone of the surface flat portion and the plastic film cut edge portion can be synchronized without a sense of incongruity, the design is excellent. Therefore, it can be widely applied to the material and shape of the adherend substrate, and can be used for a wide variety of uses such as a vertical surface, a horizontal surface, and a butt surface.

  Hereinafter, the present invention will be described in detail. The hard coat layer that forms the surface layer is made of resins such as melamine, urethane, alkyd, and acrylic for organic systems, carbon functional silane, silicon functional silane for organic and inorganic systems, and metal oxides and glass components for inorganic systems. Is used. If necessary, fine particles such as alumina, silica, zirconium oxide, fluororesin, reactive silicone oil to provide wear resistance, scratch resistance, designability, lubricity, weather resistance, antistatic properties, designability, etc. A lubricant such as hindered amine and benzotriazole, a surfactant having an antistatic function, a pigment and a dye can be added and used.

  The hard coat layer can be formed by applying a solution and drying and curing, applying (drying) and curing by heating, applying (drying) and irradiating with active energy rays (ultraviolet rays and electron beams) and curing. , Sputtering, laminating, etc. can be used. As a coating method, various methods such as a gravure coating method, a bar coating method, a roll coating method, a die coating method, a blade coating method, and a reverse roll coating method can be used, and the coating film is applied to a thickness of about 2 to 100 μm.

  Curing is selected in view of industrial productivity depending on the composition of the hard coat layer. For example, active energy ray (ultraviolet ray, electron beam) curing, cross-linking resin by combining acrylic polyol and isocyanate oligomer, heat-curing cross-linking resin of acrylic polyol (or alkyd) and melamine resin, heat condensation curing of organoalkoxysilane, etc. The method can be used.

  The hard coat layer improves the performance of decorative sheets such as scratch resistance, abrasion resistance, stain resistance, solvent resistance, light resistance, weather resistance, heat resistance, water resistance, discoloration resistance, workability, design, and touch. It is an important factor that affects. For example, active energy ray curable resins are polyester (meth) acrylate, epoxy (meth) acrylate, polyurethane (meth) acrylate, polyether (meth) acrylate, oligo (meth) acrylate, alkyd (meth) acrylate, polyol And oligomers such as (meth) acrylate. In particular, an acrylate prepolymer having a molecular weight of 1000 to 3000 is preferably used.

  Specific examples of the active energy ray polymerizable monomer include styrene monomers such as styrene, α-methylstyrene, methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, acrylic Acrylic acid esters such as methoxybutyl acid and phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, and methacrylic acid esters such as phenyl methacrylate, acrylic acid-2 -(N, N-diethylamino) ethyl, methacrylate-2- (N, N-dimethylamino) ethyl, acrylate-2- (N, N-dibenzylamino) ethyl, methacrylate-2- (N, N -Dimethylamino) Substituted amino alcohol esters of unsaturated acids with chill, acrylic acid-2- (N, N-diethylamino) propyl, unsaturated carboxylic acid amides with acrylamide, methacrylamide, etc., ethylene glycol diacrylate, diethylene glycol diacrylate, Propylene glycol diacrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, ethylene glycol acrylate, propylene glycol (Meth) acrylates such as dimethacrylate and diethylene glycol dimethacrylate, trimethylolpro Examples thereof include monomers such as polythiol compounds having two or more thiol groups in the molecule such as pantrithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycol and the like. The blending ratio of the active energy ray-polymerizable oligomer and the active energy ray-polymerizable monomer can be appropriately selected according to the viscosity of the coating solution and the performance of the cured layer, but is usually 5% by weight or more and 95% by weight or less of the monomer. The range is preferable.

  The plastic film used as the base of the printing layer in the present invention includes polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polyethylene film, polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate Film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, Polyetherimide film, polyimide film, fluorine tree Film, nylon film, an acrylic resin film or the like, all of which can be used a known film.

  Among the above-mentioned films, polyethylene terephthalate (PET) and / or copolymerized PET having excellent tensile strength, heat resistance, dimensional stability, chemical resistance, solvent resistance, transparency, and safety (not including halogen elements), among others. A film is preferable, and a biaxially stretched film is desirable. The copolymer component of the copolymerized PET film may be an acid component or an alcohol component. Examples of the acid component include isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, azelaic acid, decanedicarboxylic acid, and cyclohexanedicarboxylic acid. Examples thereof include propanediol, butanediol, hexanediol, cyclohexanedimethanol and the like. By copolymerizing, properties excellent in moldability can be obtained while maintaining the heat resistance, solvent resistance, strength and transparency of PET. The thickness is preferably in the range of 20 to 200 μm in consideration of the bendability and the sticking appearance. The surface of the plastic film may be subjected to easy adhesion treatment (for example, corona discharge treatment, primer application). By performing these treatments, wettability is improved and adhesion between the hard coat layer and the printed design layer is improved.

  The printed layer is formed on the front surface or the back surface of the plastic film by a known printing technique, for example, gravure printing so that a grain pattern and an abstract pattern are printed in 3 to 4 colors. In the case of a transparent plastic film, the pattern printed layer is desirable because the back side is deeper than the front side and the design feeling and wear resistance are excellent.

  Examples of the pressure-sensitive adhesive used in the present invention include acrylic resin-based pressure-sensitive adhesives such as poly (meth) acrylic acid and / or esters thereof and copolymers thereof with polystyrene, polyester, polyvinyl acetate, and the like, and acrylic-urethane. -Based adhesives, polyurethane resin-based adhesives, rubber-based adhesives, polyolefin-based adhesives, polystyrene-based adhesives such as SBS and SIBS, and silicone-based adhesives. In particular, the pressure-sensitive adhesive layer is "swelled" when bent, so that distortion and stress generated between the adherend and the sheet are absorbed to suppress film expansion and contraction, and the surface layer does not crack or whiten. In addition, it has the effect of absorbing strain and stress generated between the adherend and the sheet layer due to environmental changes (temperature, humidity, etc.), and has the effect of preventing blistering, interfacial delamination between the plastic sheet and the printing layer. The thickness of the pressure-sensitive adhesive layer is preferably in the range of 15 to 150 μm. In this case, when the decorative sheet is bent, if the adhesive layer is thin, it cannot follow the unevenness of the adherend and is easily peeled off. Also, when bonded to a metal plate with a thickness of 1 mm and then subjected to rapid bending at room temperature 2R (R; bending radius “mm”), the adhesive layer does not “swell”, cannot absorb strain and stress, and bend partially plastic film May be stretched to cause “whitening”, “striping”, “breaking”, or peeling of the adherend and the sheet. If it is thick, the thickness of the pressure-sensitive adhesive layer may appear in the appearance, and appearance defects such as dents may easily occur.

  Among the above-mentioned pressure-sensitive adhesives, a low-Tg soft monomer that gives tackiness, a high-Tg hard monomer that gives adhesion and cohesion, and a functional group-containing monomer for improving crosslinkability and adhesion are copolymerized Acrylic pressure sensitive adhesives are preferred. Acrylic pressure-sensitive adhesives generally have a solvent type and an emulsion type, but are not particularly limited. The solvent type contains the acrylic resin, a crosslinking agent, and optionally a tackifier in an appropriate solvent, and the emulsion type contains the acrylic resin, an emulsifier and an optional tackifier in an aqueous medium. It contains agents.

  Specific examples of the present invention will be described below, but the scope of the present invention is not limited to the embodiments.

A hard coat treatment with a UV curable resin was performed on one surface of a 125 μm thick biaxially stretched polyester film on which both surfaces were subjected to an easy adhesion treatment. For the UV hard coat treatment, the following hard coat composition was applied, dried and the solvent was removed, and then cured by irradiating ultraviolet rays from the application side with an irradiation dose of 1500 mJ / cm ^2. A coat layer was formed.

Formulation of UV curable resin to be hard coat layer Dipentaerythritol hexaacrylate 5 parts by weight Benzyldimethyl ketal (photopolymerization initiator) 0.25 part by weight Methyl isobutyl ketone (solvent) 94.75 parts by weight A printing ink using acrylic urethane resin as a medium (fixing agent) was used, and a wood grain pattern was printed on the surface opposite to the UV hard coat treated surface.

  Next, an acrylic emulsion-based adhesive (Ultrazol W-90, Tg: −54 ° C., manufactured by Gantz Kasei Co., Ltd.) was applied to the release paper with a reverse roll coater and dried so that the dry thickness was 80 μm. The pressure-sensitive adhesive surface and the aforementioned biaxially stretched polyester film woodgrain print surface were brought into contact with each other and pressed to obtain a decorative sheet of Example 1.

  Next, the release sheet of the decorative sheet was peeled off and adhered to an aluminum plate having a thickness of 1 mm to obtain a decorative plate of Example 1.

  In Example 1, it implemented similarly except having changed the thickness of the film into 50 micrometers.

  In Example 1, it implemented similarly except having changed the thickness of the film into 38 micrometers.

  In Example 1, it implemented similarly except having changed the thickness of the adhesion layer into 40 micrometers.

  In Example 4, it implemented similarly except having changed the thickness of the film into 38 micrometers.

Comparative Example 1
In Example 1, the same procedure was carried out except that a biaxially stretched polyester film having a thickness of 125 μm that had been subjected to easy adhesion treatment only on the back pattern printed surface was used, and no surface hard coat treatment was performed.

Comparative Example 2
In Example 1, it implemented similarly except having changed the thickness of the film into 16 micrometers and the adhesion layer thickness into 7 micrometers.

Comparative Example 3
An adhesive soft doubling vinyl chloride resin sheet (base material thickness 150 μm, adhesive layer thickness 40 μm, total thickness 190 μm) on which a commercially available wood grain pattern was printed was attached to a 1 mm thick aluminum plate to obtain a comparative example 3 decorative board.

Comparative Example 4
The same operation as in Example 1 was performed except that a 125 μm-thick flexible polyolefin resin film having both surfaces subjected to easy adhesion treatment was used.
The evaluation results are shown in Table 1.

The evaluation method was as follows.
(1) Dimensional stability: A crosscut was put in the center of a 10 × 10 cm test piece, and the maximum crosscut gap was measured after standing at 65 ° C. for 48 hours.
(2) Pencil hardness: Measured according to JIS K 5600-5-4 (1999 edition). The measuring apparatus used was a pencil scratch coating film hardness tester (type P) manufactured by Toyo Seiki Seisakusho.
(3) Nail scratch: The surface of the decorative sheet was strongly rubbed with the nail, and the appearance was visually observed.
(4) Abrasion resistance: JAS special decorative plywood standard. The wear value is the value when the pattern layer was first scraped off with a taper-type ablazer.
(5) Hot water resistance: JAS K 6902; 1998 (thermosetting resin high-pressure decorative board test method).
(6) Cigarette resistance; after igniting the cigarette against the decorative surface and extinguishing the fire, the decorative surface was wiped with a cloth and the appearance was confirmed.
(7) Contamination resistance: JIS K 6902; 1998 (Thermosetting resin high-pressure decorative board test method).

Contaminant 1: Black tea 2: Coffee 4: 1% iodine alcohol solution 5: Vinegar 11: Crayon 12: Black shoe ink 13: Edible red No. 102 dye 0.01% aqueous solution 14: Blue black office ink 15: 2% mercurochrome Aqueous solution 16: 5% aqueous solution of carboxylic acid 18: Soy sauce (8) Wipeability of oily marker; after writing with an oily marker, wiped off with acetone and visually confirmed the appearance.
(9) Bending workability: A bar having a prescribed R (radius mm) was used, and the state when the decorative sheet was pressed to the bar at room temperature and bent 180 degrees was written with the decorative sheet side outside.

Claims (6)

A decorative sheet comprising a hard coat layer, a design layer having a plastic film as a support, and an adhesive layer in order from the surface. The decorative sheet according to claim 1, wherein the hard coat layer has a pencil hardness of H or more. The decorative sheet according to claim 1, wherein the plastic film according to claim 1 is a biaxially stretched polyester film. The decorative sheet according to claim 3, wherein the biaxially stretched polyester film according to claim 3 has a thickness of 20 µm to 200 µm. The decorative sheet according to claim 1, wherein the adhesive layer according to claim 1 has a thickness of 15 μm to 150 μm. A decorative board comprising the decorative sheet according to claim 1 attached to a substrate.