JP2006123495A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet improved in anti-staining properties along with abrasion resistance and scratch resistance. <P>SOLUTION: In the decorative sheet for use in the state laminated on an adherend material, (1) the decorative sheet has at least a base material sheet, a pattern layer, a transparent resin layer, a primer layer and a surface protective layer in succession, (2) the primer layer includes an antistatic agent and (3) the surface protective layer is formed from a composition containing (a) an ionizing radiation polymerizable oligomer, (b) a reactive silicone acrylate and (c) spherical particles with an apparent specific gravity of 0.3-1 g/cm<SP>3</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a decorative sheet provided with an effective pattern as a surface decoration material for building materials such as furniture and joinery, and a decorative board on which the decorative sheet is laminated.

  The decorative sheet is used for the purpose of protecting the surface of an adherend such as a wooden board, decoration, and the like, and is used by sticking it on the surface of the adherend. And the decorative board obtained by this is used for various building materials, furniture, etc.

  The decorative sheet is provided with a surface protective layer to protect the outermost surface. Therefore, the surface protective layer needs to be excellent in wear resistance, scratch resistance, and the like. In addition, the surface protective layer needs to have stain resistance (antifouling property) against dirt from the outside.

  As a decorative sheet excellent in abrasion resistance, stain resistance and the like, for example, a layer (2) containing a colorant, a synthetic resin layer (3), and the synthetic resin layer on one surface of the base film (1) A decorative sheet characterized in that a synthetic resin layer (4) different from (3) is laminated in this order has been proposed (Patent Document 1).

Further, in the antifouling cosmetic material in which the antifouling layer is provided on the base material, the antifouling layer is made of a silicone-modified acrylic urethane resin in which an organopolysiloxy group is introduced into a side chain of the acrylic urethane resin. A characteristic antifouling cosmetic material has also been proposed (Patent Document 2).
JP-A-11-58614 JP 2004-17617 A

  However, in the decorative sheet of Patent Document 1, a silicone resin, a fluororesin, or the like having a low surface tension is used as the outermost synthetic resin layer. For this reason, there are problems in terms of wear resistance, handleability, slipperiness, and the like.

  In general, the decorative sheet is stored in a roll shape or in a laminated state. At this time, if a large amount of the silicone resin is bleed on the surface of the decorative sheet, it tends to adhere to the back surface of one of the decorative sheets. Even in Patent Document 1, a relatively large amount of silicone resin may bleed. When the back surface of the decorative sheet is soiled with a silicone resin, there is a possibility that predetermined adhesiveness may not be obtained when the decorative sheet is attached to a plywood or the like.

  In the decorative sheet of Patent Document 2, a silicone-modified resin is used as an antifouling layer, and the silicone-modified resin is bleeded on the surface of the decorative sheet to obtain stain resistance (particularly resistance to dirt due to writing instruments, dirt due to food, etc.). Is. Therefore, similarly to Patent Document 1, a problem due to bleeding of the silicone-modified resin occurs.

  Moreover, in patent document 2, since the silicone modified resin which has formed the antifouling layer on the surface is wiped off at the same time by wiping off the decorative sheet, it is difficult to maintain the stain resistance for a long period of time. become.

  Accordingly, a main object of the present invention is to efficiently provide a decorative sheet having improved abrasion resistance as well as abrasion resistance and scratch resistance.

  In light of the problems of the prior art, the present inventor has found that the above object can be achieved by using a laminate having a specific configuration as a decorative sheet as a result of intensive studies, and has completed the present invention. .

  That is, the present invention relates to the following decorative sheet.

1. A decorative sheet for use by laminating on an adherend,
(1) The sheet has at least a base sheet, a pattern layer, a transparent resin layer, a primer layer, and a surface protective layer in this order.
(2) The primer layer contains an antistatic agent,
(3) The surface protective layer is formed of a composition comprising a) ionizing radiation polymerizable oligomer, b) reactive silicone acrylate, and c) spherical particles having an apparent specific gravity of 0.3 to 1 g / cm ³ .
A decorative sheet characterized by that.

  2. Item 2. The decorative sheet according to Item 1, wherein the spherical particles have a pore volume of 0.5 ml / g or less.

  3. Item 3. The decorative sheet according to Item 1 or 2, wherein the surface protective layer contains a matting agent.

  4). Item 4. The decorative sheet according to any one of Items 1 to 3, wherein a part or all of the spherical particles are silica particles.

  5. Item 5. The decorative sheet according to any one of Items 1 to 4, wherein the surface protective layer has irregularities formed by embossing.

  6). The ionizing radiation polymerizable oligomer comprises (A) a urethane (meth) acrylate oligomer having at least two radical polymerizable unsaturated groups in one molecule and (B) 3 to 15 radical polymerizable nonpolymers in one molecule. Item 6. The decorative sheet according to any one of Items 1 to 5, comprising an aliphatic urethane (meth) acrylate oligomer having a saturated group.

  7. Item 7. The decorative sheet according to any one of Items 1 to 6, wherein at least one of the transparent resin layer and the base sheet is a polyolefin resin.

  8). The decorative board formed by laminating | stacking the said sheet | seat on a to-be-adhered material so that the surface protection layer of the decorative sheet in any one of said claim | item 1-7 may become an outermost surface layer.

According to the decorative sheet of the present invention, the surface protective layer is formed by a composition comprising a) an ionizing radiation polymerizable oligomer, b) a reactive silicone acrylate, and c) a spherical particle having an apparent specific gravity of 0.3 to 1 g / cm ^3. Therefore, it exhibits excellent stain resistance (particularly ink repellent properties), abrasion resistance, scratch resistance and the like while avoiding the problem of silicone bleeding. In particular, when high-density particles having an oil absorption of 50 ml / 100 g or less and / or a pore volume of 0.5 ml / g or less are used as the spherical particles, excellent scratch resistance can be obtained without damaging the coating machine. . That is, it is effective in preventing scratches that are easily attached during post-processing and transportation of the decorative sheet.

  The decorative sheet of the present invention is provided with an antistatic layer (primer layer) as a second layer from the outermost layer of the sheet, so that the antistatic property (prevents dust) while maintaining the above-mentioned contamination and scratch resistance performance. Demonstrate. Since it is difficult for dust to adhere, it is difficult for foreign matter to enter between the base material and the base material during processing, and it is effective in preventing the occurrence of scratches due to foreign matter contamination.

The decorative sheet of the present invention is a decorative sheet for use by being laminated on an adherend,
(1) The sheet has at least a base sheet, a pattern layer, a transparent resin layer, a primer layer, and a surface protective layer in this order.
(2) The primer layer contains an antistatic agent,
(3) The surface protective layer is formed of a composition including a) an ionizing radiation polymerizable oligomer, b) a reactive silicone acrylate, and c) a spherical particle having a specific gravity of 0.3 to 1 g / cm ³ .
It is characterized by that. Hereinafter, each layer will be described.

As the base sheet , for example, paper, non-woven fabric, thermoplastic resin sheet, or a composite material thereof is used.

  Examples of the paper include thin paper, kraft paper, high quality paper, linter paper, baryta paper, sulfate paper, and Japanese paper.

Moreover, as a nonwoven fabric, the nonwoven fabric which consists of fibers, such as a polyester resin, an acrylic resin, nylon, vinylon, glass, is mentioned, for example. The basis weight of the paper or non-woven fabric is usually about ²⁰ to 100 g / m ² . In addition, for paper or non-woven fabric, resin such as acrylic resin, styrene butadiene rubber, melamine resin, urethane resin is added to strengthen the interlaminar strength between the fibers and other layers, and to prevent galling. It may be impregnated with resin or embedded during papermaking. Note that a decorative sheet using paper (or non-woven fabric) as a base sheet is decorative paper.

  Examples of the thermoplastic resin sheet include acrylic resin, polyester resin, polyolefin resin, polyvinyl chloride resin, polystyrene, ABS resin, polycarbonate resin, and polyamide resin. More specifically, the following (1) to (4) may be mentioned.

(1) Polyethylene (high density, medium density, or low density), polypropylene (isotactic or syndiotactic), polybutene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, olefin Polyolefin resins such as thermoplastic elastomers The olefin thermoplastic elastomers include hard segments made of crystalline polyolefin resins as exemplified above, ethylene-propylene rubber, ethylene-propylene-diene rubber, atactic polypropylene, styrene- A soft segment made of an elastomer such as butadiene rubber or hydrogenated styrene-butadiene rubber is mixed. The mixing ratio of the hard segment and the soft segment is about [soft segment / hard segment] = 5/95 to 40/60 (mass ratio). If necessary, the elastomer component is crosslinked by a known crosslinking agent such as sulfur or hydrogen peroxide.

  (2) Acrylic resins such as polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, methyl (meth) acrylate-styrene copolymer [however, (meth) Acrylate means acrylate or methacrylate].

(3) Polyester resin such as polyethylene terephthalate, polybutylene terephthalate, ethylene-terephthalate-isophthalate copolymer, polyethylene naphthalate, polyester-based thermoplastic elastomer, amorphous polyester, etc. The segment has a high crystalline and high melting point aromatic polyester, and the soft segment has a block polymer using amorphous polyether having a glass transition temperature of −70 ° C. or less. For example, polybutylene terephthalate is used as the polyester, and polytetramethylene glycol or the like is used as the amorphous polyether. The amorphous polyester is typically an ethylene glycol-1,4-cyclohexanedimethanol-terephthalic acid copolymer.

(4) Other resins For example, polycarbonate resin, polyvinyl chloride resin, polyamide resin, polyphenylene sulfide, polyether ether ketone and the like can be mentioned.

  As a layer structure of the base sheet, the above-mentioned paper, non-woven fabric, thermoplastic resin sheet and the like can be used by laminating them in a single layer or two or more layers.

  In the decorative sheet of the present invention, it is preferable that either the base sheet or the transparent resin layer described later is a polyolefin resin.

  Although the thickness (total thickness in the case of a laminated body) of a base material sheet is not limited, Generally, What is necessary is just to be about 25-500 micrometers.

Pattern layer The pattern layer can represent not only patterns of natural materials such as wood grain and joints, but also letters, symbols, drawings, and the like.

  In the case of providing a pattern layer, the pattern layer forming method, material, pattern type, and the like are not particularly limited. The pattern layer is usually formed using ink and can be formed by a known printing method such as gravure printing, silk screen printing, offset printing, gravure offset printing, and ink jet printing. As the picture pattern, for example, a grain pattern, a stone pattern, a grain pattern, a cloth pattern, a tile-like pattern, a brick-like pattern, a leather pattern, a character, a symbol, a geometric pattern, or a combination of two or more of these can be adopted.

  The ink used for forming the pattern layer is 1) a vehicle composed of a binder, 2) a colorant such as a pigment or dye, 3) an extender pigment, a stabilizer, a plasticizer, a catalyst, a curing agent, etc. Consists of various additives.

  The binder resin may be appropriately selected from known binders such as a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin according to required physical properties, printability, and the like. For example, cellulose resins such as nitrocellulose, cellulose acetate, cellulose acetate propionate; poly (meth) methyl acrylate, poly (meth) butyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate- ( In addition to an acrylic resin such as a (meth) acrylic acid 2-hydroxyethyl copolymer, a simple substance such as urethane resin, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, or a mixture containing these can be used.

  In addition, as coloring agents, inorganic pigments such as titanium white, carbon black, iron black, petal, yellow lead and ultramarine, organic pigments such as aniline black, quinacridone red, isoindolinone yellow and phthalocyanine blue, titanium dioxide coated mica In addition to bright pigments such as foil powder such as aluminum, various dyes can be used.

Adhesive Layer In the decorative sheet of the present invention, an adhesive layer is preferably interposed between the pattern layer and the transparent resin layer.

  The adhesive used in the adhesive layer can be appropriately selected from known or commercially available adhesives according to the components constituting the pattern layer or the transparent resin layer. Examples thereof include thermosetting resins such as polyester resins, polyurethane resins, and epoxy resins, in addition to polyolefin resins such as polyethylene and polypropylene. These resins may be used in the state of an emulsion.

  Among these, in this invention, a urethane type resin adhesive is preferable at the point that heat resistance etc. can be improved more. Examples of the urethane resin adhesive include a two-component curable urethane resin having a polyol as a main component and an isocyanate as a crosslinking agent (curing agent).

  The polyol has two or more hydroxyl groups in the molecule. For example, polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, polycarbonate polyol and the like are used.

  Moreover, as said isocyanate, the polyvalent isocyanate which has a 2 or more isocyanate group in a molecule | numerator is used. For example, aromatic isocyanates such as 2,4-tolylene diisocyanate, xylene diisocyanate, 4,4-diphenylmethane diisocyanate, aliphatics such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate (or Alicyclic) isocyanates are used. Further, adducts or multimers of the above various isocyanates can also be used. Examples thereof include adducts of tolylene diisocyanate and trimers of tolylene diisocyanate.

  If necessary, the adhesion surface can be subjected to known easy adhesion treatment such as corona discharge treatment, plasma treatment, degreasing treatment, and surface roughening treatment.

  What is necessary is just to implement as an adhesion | attachment method according to a well-known method according to the kind etc. of adhesive to be used. For example, using a polyolefin resin such as polyethylene or polypropylene, a method of coating on a pattern layer by melt extrusion (extrusion coating method), a thermosetting resin such as a polyester resin, a polyurethane resin, or an epoxy resin, isocyanate, Apply an adhesive such as a crosslinking agent such as amine, a polymerization initiator such as methyl ethyl ketone peroxide, hydroperoxide, azabisisobutyronitrile, a polymerization accelerator such as cobalt naphthenate, dimethylaniline, etc. A dry laminating method can be employed. In the present invention, an adhesive capable of thermocompression bonding is used, and the pattern layer and the transparent resin layer can be laminated by thermocompression bonding.

  In the present invention, a known easy adhesion treatment such as a corona discharge treatment, a plasma treatment, a degreasing treatment, a surface roughening treatment or the like can be applied to the adhesion surface as necessary.

  The thickness of the adhesive layer varies depending on the type of the transparent protective layer, the type of adhesive to be used, and the like, but is usually about 0.1 to 30 μm.

Transparent resin layer The transparent resin layer is not limited as long as it is transparent. Accordingly, it includes any of colorless and transparent, colored and transparent, translucent and the like.

  As a transparent resin layer, what was formed, for example with the thermoplastic resin can be used conveniently. Specifically, soft, semi-rigid or rigid polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer Polymers, ionomers, acrylic esters, methacrylic esters and the like can be mentioned. In the present invention, a polyolefin resin such as polypropylene is particularly preferable as the transparent resin layer.

  The transparent resin layer may be colored as necessary. In this case, a coloring material (pigment or dye) can be added to the above thermoplastic resin for coloring. As the colorant, known or commercially available pigments or dyes can be used as appropriate. These can select 1 type, or 2 or more types. Further, the addition amount of the colorant may be appropriately set according to the desired color tone.

  For the transparent resin layer, a filler, a matting agent, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a radical scavenger, a soft component (as necessary) For example, various additives such as rubber) may be included.

  A flame retardant is added in order to provide flame resistance. For example, chlorinated paraffin, tricresyl phosphate, chlorinated oil, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, tetrabromobisphenol A, dibromopropyl phosphate, tri (2,3-dibromopropyl) phosphate, antimony oxide, hydrous alumina Barium borate and the like can be preferably used.

  Antioxidants are added to suppress or prevent oxidative degradation. For example, alkylphenols, amines, quinones and the like are suitable.

  It absorbs ultraviolet rays in a wavelength range of 280 to 450 nm, which causes deterioration of ultraviolet absorbers and resins (particularly polyolefin resins). Examples thereof include benzophenone-based, salicylate-based, benzotriazole-based, and acrylonitrile-based ultraviolet absorbers.

  The radical scavenger is added to prevent discoloration due to sunlight, cracks, whitening, strength deterioration and the like and improve weather resistance. As the radical scavenger, in addition to bis- (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, for example, a hindered amine radical scavenger such as a compound disclosed in JP-B-4-82625, Piperidyl radical scavengers and the like are used.

  The forming method of the transparent resin layer is not limited, for example, a method of laminating a preformed sheet or film on an adjacent layer, an adjacent layer by melt-extruding a resin composition capable of forming a transparent resin layer Any of a method of coating on top and a method of laminating together with an adjacent layer can be employed. In the present invention, it is particularly preferable to form the transparent resin layer by melt extrusion. In particular, the transparent resin layer is preferably applied by melt extrusion of a polyolefin resin. Specifically, the transparent resin layer can be suitably formed by forming an adhesive layer on the pattern layer in advance, and melt-extruding and applying a polypropylene-based thermoplastic elastomer onto the adhesive layer. What is necessary is just to implement the method of melt extrusion according to the well-known method using a T die etc., for example.

The thickness of the transparent resin layer can be appropriately set depending on the use of the final product, the method of use, etc., but it is generally preferably 50 to 250 μm, particularly preferably about 20 to 200 μm.
The front surface (front surface) and / or the back surface of the transparent resin layer can be subjected to corona discharge treatment as necessary in order to enhance the adhesion with the adjacent layer. The method and conditions for the corona discharge treatment may follow a known method.

  In the present invention, it is desirable to form a primer layer on the back surface of the transparent resin layer. Examples of the material for forming the back primer layer include polyester resins, polyurethane resins, acrylic resins, polycarbonate resins, vinyl chloride / vinyl acetate copolymers, polyvinyl butyral resins, nitrocellulose resins, and alkyl resins. Compounds such as titanate and ethyleneimine can also be used. In particular, the back primer layer is preferably a two-component curable urethane resin. It is preferable to use fatty acid isocyanate (aliphatic isocyanate) such as hexamethylene diisocyanate (HMDI) as the isocyanate and acrylic polyol as the polyol, because more excellent weather resistance and adhesion can be obtained.

  The back primer layer can be formed according to a known printing method, coating method or the like using these as they are or in a state dissolved or dispersed in a solvent.

  Although the thickness of a back surface primer layer is not limited, Usually, about 1-3 micrometers is preferable and about 2 micrometers is more preferable.

Primer layer The decorative sheet of the present invention has an essential primer layer containing an antistatic agent between the transparent resin layer and the surface protective layer.

  The primer layer is not particularly limited as long as it contains an antistatic agent.

  The antistatic agent added to the primer layer is not limited, but there are cationic, anionic, nonionic, amphoteric, and the like depending on the type of ionic species. In addition, according to the classification by molecular weight, there is a polymer type called an antistatic resin which is a polymer such as a copolymer, in addition to the so-called low molecular type. The antistatic agent may be appropriately selected from these conventionally known antistatic agents according to the required physical properties, applications and the like.

  Among these antistatic agents, cationic ones are preferable in that strong antistatic properties can be easily obtained. Specifically, examples of the cationic system include quaternary ammonium salts. The polymer type is preferable to the low molecular type in that, for example, the physical properties such as compatibility can be easily adjusted by appropriately selecting a copolymerization monomer. Therefore, as the antistatic agent, a cationic polymer type is preferable, and for example, a cationic polymer type antistatic agent having a quaternary ammonium salt is preferable.

  What is necessary is just to set the addition amount of an antistatic agent suitably according to a use, a required physical property, the kind of antistatic agent, etc. In general, the polymer type is added in a larger amount than the low molecular type. The addition amount of the antistatic agent is, for example, about 30 to 120% by weight with respect to the resin content.

  Although there is a conductive agent in terms of providing antistatic performance, carbon powder or the like has a problem that the appearance of the decorative sheet is darkened and the design is impaired. Antimony-doped tin oxide (ITO) powder, tin oxide-treated titanium oxide powder, and the like have problems such as white turbidity and high cost. These inorganic compounds are generally not preferred as antistatic agents for decorative sheets.

  Further, when a specific extender pigment is added as an inorganic filler together with an antistatic agent to the primer layer, an effect of further improving the antistatic property can be obtained. In addition, if the equivalent antistatic performance can be obtained by adding the extender pigment, the amount of the antistatic agent added can be reduced and the resin content can be reduced, so that the desired performance can be realized at a lower cost. There are also benefits. As the extender pigment (antistatic auxiliary agent), for example, barium sulfate is preferable. In the case of containing barium sulfate, not only antistatic properties but also weather resistance adhesion can be improved. On the other hand, calcium carbonate as an extender has improved antistatic properties, but it is difficult to use for decorative sheets because of poor weather resistance adhesion.

  Although the addition amount of the said barium sulfate is not limited, For example, what is necessary is just to be about 50 to 500 weight% normally with respect to a resin part. If the amount added is too large, the primer layer surface may be roughened and the original adhesion may be reduced.

  As the resin component for forming the primer layer, the resin component constituting the back primer of the transparent resin layer described above can be used. Of these, urethane resins are preferred, and the use of two-component curable urethane resins is particularly preferred. It is preferable to use fatty acid isocyanate (aliphatic isocyanate) such as hexamethylene diisocyanate (HMDI) as the isocyanate and acrylic polyol as the polyol, because more excellent weather resistance and adhesion can be obtained.

  The primer layer can be formed according to a known printing method, coating method or the like using these as they are or in a state dissolved or dispersed in a solvent.

  Although the thickness of a primer layer changes with uses etc., about 1-10 micrometers is preferable normally.

Surface protective layer In the present invention, the surface protective layer is provided as the outermost surface layer. The surface protective layer may be colored as long as it is transparent. Moreover, it may be translucent as long as the pattern layer is visible. By forming the surface protective layer, the surface of the decorative sheet can be easily damaged and the scratch resistance can be improved.

In the decorative sheet of the present invention, the surface protective layer is formed by a composition comprising a) an ionizing radiation polymerizable oligomer, b) a reactive silicone acrylate, and c) a spherical particle having an apparent specific gravity of 0.3 to 1 g / cm ^3. ing.

(Ionizing radiation polymerizable oligomer)
As the ionizing radiation polymerizable oligomer, those used for known ionizing radiation curable resins can be applied. In particular, in the present invention, more specifically, (A) a urethane (meth) acrylate oligomer having at least two radically polymerizable unsaturated groups in one molecule and (B) 3 to 15 in one molecule. It preferably contains an aliphatic urethane (meth) acrylate oligomer having a radically polymerizable unsaturated group.

  The urethane (meth) acrylate oligomer (A) is one having two radical polymerizable unsaturated groups in one molecule (so-called bifunctional urethane acrylate oligomer). This includes, for example, a) a diisocyanate, b) a polyhydric alcohol having two or more hydroxyl groups in one molecule (preferably a weight average molecular weight of 500 to 2000), c) a hydroxyl group at the terminal and a radically polymerizable unsaturated group. An oligomer formed by bonding a (meth) acrylate compound to be included is mentioned. This oligomer preferably has a weight average molecular weight of 1000 to 4000. If the molecular weight is less than 1000, the cured resin layer may not fully exhibit the flexibility of urethane (meth) acrylate, and the workability during bending and embossing such as V-cut processing and lapping processing is reduced. To do. On the other hand, when the molecular weight exceeds 4000, there is a possibility that characteristics such as contamination resistance may be deteriorated.

  The diisocyanate a) is an aliphatic, alicyclic or aromatic isocyanate having two or more isocyanate groups in one molecule, such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1 , 6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like.

  Examples of the polyhydric alcohol b) include polyester polyols having a hydroxyl group at both ends, polyether polyols, polycarbonate polyols, and acrylic polyols. Examples of the polyester polyol include (a) an addition reaction product of a diol compound having an aromatic or spiro ring skeleton and a lactone compound or a derivative thereof or an epoxy compound, and (b) a condensation product of a polybasic acid and an alkylene glycol. And (c) a ring-opening polyester compound derived from a cyclic ester compound, and these can be used alone or in admixture of two or more. For example, a polyester diol having a hydroxyl group at both ends (particularly a weight average molecular weight of 500 to 2000) obtained as a condensation product with an alkylene glycol using adipic acid as the polybasic acid of (b) above has various physical properties. Therefore, it is preferably used. Examples of the polyether polyol include polytetramethylene ether glycol, polyethylene glycol, and polypropylene glycol.

  The (meth) acrylate c) is an ester compound of acrylic acid or methacrylic acid or a derivative thereof, and has a hydroxyl group at the terminal. Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxylpropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5-hydroxycyclooctyl (meth) acrylate , (Meth) acrylic acid ester compounds having one polymerizable unsaturated group such as 2-hydroxy-3-phenyloxypropyl acrylate, etc., or having two or more polymerizable unsaturated groups in one molecule (meth) Examples include acrylic ester compounds.

  In the present invention, in the urethane (meth) acrylate oligomer (A), the polyhydric alcohol component is preferably a polyester polyol having a weight average molecular weight of 500 to 2000 formed from alkylene glycol and adipic acid, and the diisocyanate component is isophorone. An oligomer having a weight average molecular weight of 1000 to 3000 obtained by reacting these with diisocyanate and acrylate component as hydroxyethyl (meth) acrylate is desirable.

  The aliphatic urethane (meth) acrylate oligomer (B) has a radically polymerizable unsaturated group such as 3 to 15 (meth) acryloyl groups in one molecule. This is obtained by reacting a) an aliphatic diisocyanate, b) a polyfunctional polyol, c) a (meth) acrylate having a hydroxyl group at the terminal and having a radically polymerizable unsaturated group. ) Urethane acrylate.

  Examples of the aliphatic diisocyanate a) include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like.

  As the polyfunctional polyol b), those having the polyhydric alcohol as a basic skeleton and having a plurality of functional groups can be used.

  The above (meth) acrylate c) is 2-hydroxyethyl (meth) acrylate, 2-hydroxylpropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5-hydroxycyclooctyl Examples include (meth) acrylic acid ester compounds having one polymerizable unsaturated group such as (meth) acrylate and 2-hydroxy-3-phenyloxypropyl acrylate.

  As the ionizing radiation polymerizable oligomer of the present invention, (A) urethane (meth) acrylate oligomer having at least two radical polymerizable unsaturated groups in one molecule and (B) 3 to 15 in one molecule. A mixture containing an aliphatic urethane (meth) acrylate oligomer having a radically polymerizable unsaturated group can be suitably used. In particular, as an ionizing radiation polymerizable oligomer, (A) 40 to 80% by weight of urethane (meth) acrylate oligomer having at least two radically polymerizable unsaturated groups in one molecule and (B) 3 to 15 in one molecule. It is desirable to use a mixture composed of 60 to 20% by weight of an aliphatic urethane (meth) acrylate oligomer having one radical polymerizable unsaturated group. When the amount (A) is less than 40% by weight, the flexibility and malleability of the curable resin layer become insufficient, and the impact resistance may be lowered. On the other hand, when (A) exceeds 70% by weight, scratch resistance and contamination resistance may be lowered. In addition, the compounding quantity of said urethane (meth) acrylate oligomer (A) and aliphatic urethane (meth) acrylate oligomer (B) is the said oligomer (A) and oligomer in the coating composition which forms a curable resin layer. It represents the weight percent of each component relative to the total weight of (B).

(Reactive silicone acrylate)
Although it does not specifically limit as reactive silicone acrylate, What reacts with the said electron beam radiation polymerizable oligomer is preferable. The silicone acrylate has a structure called a dimethylsiloxane structure. Type of functional group: In particular, when considering EB curing (electron beam irradiation), a methacryl group, an acrylic group, and a mercapto group are preferable.

  In the present invention, the above silicone acrylate may be present as it is in the mixture with the electron beam curable polymerizable oligomer, but may be copolymerized with the above oligomer to some extent. Such an embodiment is also included.

  The content of the reactive silicone acrylate can be appropriately determined according to the type of ionizing radiation polymerizable oligomer, etc., but is usually 5% by weight or less in the above mixture, more preferably 0.1 to 3.0% by weight, In particular, the range of 0.5 to 2.0% by weight is more preferable.

(Spherical particles)
As the spherical particles, those having an apparent specific gravity of 0.3 to 1 g / cm ³ , preferably 0.65 to 0.85 g / cm ³ are used. By including the spherical particles in such a range, the scratch resistance of the surface protective layer can be sufficiently obtained.

  In addition, the apparent specific gravity of the spherical particles in the present specification is a value measured by a method based on JIS K 5101.

  The average particle size of the spherical particles is not limited, but in general, the average particle size is preferably 5 μm or less.

  The spherical particles preferably have an oil absorption of 50 ml / 100 g or less. That is, it becomes easy to improve the scratch resistance by using higher-density spherical particles.

The specific surface area (BET specific surface area) of the spherical particles is usually preferably about 0 to 50 m ² / g.

  The pore volume of the spherical particles is usually preferably 0.5 ml / g or less, more preferably about 0.1 to 0.4 ml / g. That is, it is easy to improve the scratch resistance by using higher density particles.

  The spherical particles are not limited as long as the material has the above physical properties. For example, in addition to inorganic particles such as silica, wollastonite, and alumina, resin particles such as acrylic can also be used. In the present invention, silica particles can be particularly preferably used, and it is preferable to set so that part or all of the spherical particles become silica particles.

  The content of the spherical particles is not particularly limited and can be appropriately determined according to the type of the ionizing radiation polymerizable oligomer, but is usually preferably about 1 to 10% by weight, particularly preferably 3 to 5% by weight in the mixture.

(Other additives)
The decorative sheet of the present invention may contain any additive other than those described above in the surface protective layer. For example, a known matting agent may be included to enhance the matte feeling on the outermost surface of the decorative sheet.

  Examples of the matting agent include inorganic particles such as silica and silicone resin (powder, beads); organic material powders or beads such as crosslinked alkyl, crosslinked styrene, inzoguanamine resin, urea-formaldehyde resin, phenol resin, polyethylene, and nylon. Etc. Among these, silica can be particularly preferably used. It is also preferable to use untreated silica. The reason is that the organically treated silica treated with wax may bleed from the sheet surface in combination with a liquid repellent material.

The matting agent includes particles having an oil absorption of 100 ml / 100 g or more (particularly 200 to 400 ml / 100 g), particles having a pore volume of 0.6 ml / g or more (particularly 1 to 1.7 ml / g), and an apparent specific gravity of 0.3. It is preferable to use particles of 08 to 0.4 g / cm ³ . By using particles having such a relatively small density, a desired matte feeling can be imparted to the decorative sheet surface.

  The particle size of the matting agent is not limited, and can be appropriately determined according to the use. In general, a particle size of about 0.1 to 30 μm is preferable, and a particle size of 3 to 6 μm is particularly preferable.

  The content of the matting agent is not limited, but is preferably 3 to 20 parts by weight, particularly 5 to 15 parts by weight with respect to 100 parts by weight of the mixture.

  The composition can be prepared by mixing these components uniformly. The formation method of the surface protective layer by this composition may follow a well-known method, for example, the coating film by the said composition may be formed, and what is necessary is just to carry out cross-linking hardening of a coating film by electron beam irradiation on well-known use conditions.

  As an electron beam source of ionizing radiation, various electron beam accelerators such as a cockcroft 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 are used. Preferably, what irradiates the electron with the energy of 200-300 keV can be used. Further, as the ultraviolet light source, for example, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light, a metal halide lamp may be used.

  The surface protective layer (that is, the outermost surface of the decorative sheet) is preferably provided with an uneven pattern by embossing or the like. More preferably, a wiping process for filling the embossed concave portion with ink is performed, and the surface is coated with a two-component curable urethane resin (primer layer) and an ionizing radiation polymerizable oligomer (overcoat treatment).

  Embossing is performed to give a desired texture such as the surface of a wood board to the decorative sheet. For example, after the surface of the decorative sheet (olefin resin) is heated and softened on a heating drum, it is further heated to 160 to 180 ° C. with an infrared radiation heater, and pressed and shaped with an embossed plate provided with an uneven pattern of a desired shape. And cooled and fixed. For this, a known single wafer or rotary embossing machine may be used. Examples of the concavo-convex pattern include a wood grain conduit groove, a float pattern (a concavo-convex pattern of a raised annual ring), a hairline, a grain, a satin, and the like, and a desired pattern can be appropriately selected from these.

  The wiping process is a process of filling ink while scratching the surface with a doctor blade in a recess provided by embossing. As the wiping ink, an ink having a two-component curable acrylic urethane copolymer resin as a binder can be used. In the wiping process, the product value can be increased by expressing the design closer to the actual wood grain, particularly by performing on the wood grain conduit groove unevenness.

Adhering material The adhering material to which the decorative sheet of the present invention is applied is not limited, and the same materials as known decorative sheets can be used. For example, a wood material, a metal, ceramics, plastics, glass, etc. are mentioned. In particular, the decorative sheet of the present invention can be suitably used for a wood material. Specific examples of wood materials include veneer, wood veneer, wood plywood, particle board, medium density fiberboard (MDF) made from various materials such as cedar, firewood, firewood, pine, lawan, teak, and melapie. ) And the like.

Lamination on adherend The decorative sheet of the present invention is laminated on various adherends and used as a decorative board. The laminating method is not limited. For example, a method of sticking the base sheet side of the decorative sheet to the adherend with an adhesive can be employed. In this case, the surface protective layer becomes the outermost surface layer. What is necessary is just to select an adhesive agent suitably from well-known adhesive agents according to the kind etc. of to-be-adhered material. Examples include polyvinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ionomer, butadiene / acrylonitrile rubber, neoprene rubber, and natural rubber.

  The decorative board produced in this way is, for example, interior decoration materials for buildings such as walls, ceilings and floors, surface decorative boards for furniture such as window frames, doors and handrails, furniture or light electrical appliances, cabinets such as OA equipment. It can be preferably used for a surface decorative board or the like.

  The following examples illustrate the features of the present invention more clearly. However, the present invention is not limited to the scope of the examples.

Example 1
A polypropylene resin film (thickness 60 μm, transmittance 10%) was prepared as a base sheet. After the front and back surfaces were subjected to corona discharge treatment, a woodgrain pattern layer was formed on the front surface by gravure printing. On the other hand, a primer layer was formed on the back surface by gravure printing.

  Next, a coating solution made of a two-component curable urethane resin was applied on the pattern layer to form an adhesive layer (thickness 3 μm). Furthermore, a transparent thermoplastic resin layer (thickness 80 μm) was formed by melt extrusion coating a polypropylene thermoplastic elastomer made of an ethylene-propylene-butene copolymer with a T-die.

  A primer layer was formed on the transparent resin layer. The primer layer is composed of a two-component curable urethane resin composed of an acrylic-urethane block polymer (main agent) and hexamethylene diisocyanate (curing agent), an antistatic agent 25% by weight (quaternary ammonium), and an antistatic auxiliary agent. A primer layer (thickness: 2 μm) was formed by applying a material containing 30% by weight (barium sulfate).

  Next, a surface protective layer was formed using a composition containing the components shown in Table 1.

[In Table 1, the numerical value indicates “% by weight”. The numerical values of the oligomer (A) and the oligomer (B) indicate the weight ratio of each oligomer when the total weight of both is 100% by weight. The numerical values of silicone and spherical particles indicate the content ratio in the coating composition. ]
The following were used for each component in Table 1.
・ Oligomer (A): Urethane (meth) acrylate oligomer having at least two radically polymerizable unsaturated groups in one molecule ・ Oligomer (B): 3 to 15 radically polymerized / unsaturated groups in one molecule Aliphatic urethane (meth) acrylate oligomer having: Silicone (reactive silicone acrylate): Reactive silicone acrylate on both ends Spherical particles: Apparent specific gravity 0.65 to 0.85 g / cm ³ , Oil absorption 45 ml / 100 g, BET ratio Surface area 0 m ² / g, average particle size 3.6 μm, pore volume: 0.1 ml / g
After forming a coating film with each composition shown in Table 1, a surface protective layer (thickness 5 μm) is formed by irradiating an electron beam under the conditions of 175 keV and 5 Mrad (50 kGy) to crosslink and cure the coating film. did.

  Finally, the surface protective layer side is heated with an infrared non-contact type heater to soften the base sheet and the transparent resin layer, and then immediately embossed from the surface of the surface protective layer with heat pressure to form a wood grain conduit groove pattern A predetermined decorative sheet was obtained by shaping the uneven pattern.

Comparative Examples 1-4
A decorative sheet was prepared in the same manner as in Example 1 except that a surface protective layer was formed according to the composition shown in Table 1 and Comparative Examples 3 and 4 did not use an antistatic agent and an antistatic aid.

Test example 1
The following physical properties of the decorative sheets obtained in Examples and Comparative Examples were examined. The results are shown in Table 2.
(1) Antifouling properties (repellency test)
Using thick magic inks (black, blue and red, oily Uchida Yoko Seisaku Magic), the repelling properties were confirmed when written on the surface protective layer of the decorative sheet. A state where the magic was repelled (that is, the magic was a droplet) was evaluated as good (◯), and a dull state where the magic was not repelled was evaluated as poor (×).
(2) Antistatic properties (tobacco ash test)
The surface of the decorative sheet was rubbed 20 times with a waste cloth, and the ash adhesion was visually confirmed by bringing tobacco ash closer to the charged sample. Those without ash were evaluated as good (◯), and those without ash were evaluated as poor (x).
(3) Scratch resistance (steel wool test)
The surface of the decorative sheet was reciprocated 20 times with steel wool (load: 300 g / cm ² ), and the presence or absence of damage was visually confirmed. An unwound object was evaluated as good (◯), and an injured object was evaluated as bad (x).

Claims (8)

A decorative sheet for use by laminating on an adherend,
(1) The sheet has at least a base sheet, a pattern layer, a transparent resin layer, a primer layer, and a surface protective layer in this order.
(2) The primer layer contains an antistatic agent,
(3) The surface protective layer is formed of a composition comprising a) ionizing radiation polymerizable oligomer, b) reactive silicone acrylate, and c) spherical particles having an apparent specific gravity of 0.3 to 1 g / cm ³ .
A decorative sheet characterized by that.   The decorative sheet according to claim 1, wherein the spherical particles have a pore volume of 0.5 ml / g or less.   The decorative sheet according to claim 1 or 2, wherein the surface protective layer contains a matting agent.   The decorative sheet according to any one of claims 1 to 3, wherein a part or all of the spherical particles are silica particles.   The decorative sheet according to any one of claims 1 to 4, wherein the surface protective layer has irregularities formed by embossing.   The ionizing radiation polymerizable oligomer comprises (A) a urethane (meth) acrylate oligomer having at least two radical polymerizable unsaturated groups in one molecule and (B) 3 to 15 radical polymerizable nonpolymers in one molecule. The decorative sheet according to any one of claims 1 to 5, comprising an aliphatic urethane (meth) acrylate oligomer having a saturated group.   The decorative sheet according to any one of claims 1 to 6, wherein at least one of the transparent resin layer and the base sheet is a polyolefin resin.   A decorative board formed by laminating the sheet on the adherend so that the surface protective layer of the decorative sheet according to any one of claims 1 to 7 becomes an outermost surface layer.