JP4248728B2 - Manufacturing method of decorative sheet - Google Patents

Description

【００３７】
【発明の効果】
本発明は以上の構成であるから、下記に示す如き効果がある。
すなわち、紫外線効果型樹脂が有する優れた耐傷つき性を損なうことなく、密着性に優れ、化粧板のＶカット及びラッピング後の後加工性にも優れた化粧シートを提供することが可能となった。
【図面の簡単な説明】
【図１】本発明の一実施例を示す、トップコートが施された化粧シートを断面で表した説明図である。
【符号の説明】
１ ……基材層
２ ……絵柄層
３ ……接着剤層
４ ……表面保護層（透明フィルム）
５ ……エンボス模様
６ ……トップコート層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a decorative sheet used for furniture, joinery, building materials, doors and other building interior materials, and is excellent in adhesion to an adherend and has a high scratch resistance, while being bent such as V-cut and lapping. The present invention relates to a suitable decorative sheet.
[0002]
[Prior art]
Conventionally, as a top coat for decorative sheets used for building interior materials such as furniture, joinery, construction materials, and doors, urethane resins have been used because of their toughness, flexibility and price. And the reaction of isocyanate. However, there is a limit to scratch resistance, and non-vinyl chloride decorative sheets that take into account recent environmental problems, especially decorative sheets using olefin resins, are more scratch resistant than conventional vinyl chloride decorative sheets. It is said that it is inferior to.
[0003]
In order to improve the scratch resistance, recently, an ionizing radiation curable resin that has been applied to an olefin-based decorative sheet as a top coat has been proposed. However, although the top coat obtained thereby has a marked improvement in scratch resistance, whitening and cracking occur in the bent portion during post-processing such as V-cut and lapping required as a decorative sheet for building materials. Furthermore, there is a problem in the adhesion of the top coat because the curing shrinkage during curing is too large.
[0004]
[Problems to be solved by the invention]
The present invention has been made in order to solve such problems, and the problem is that the present invention has excellent scratch resistance and adhesion as compared with conventional top coats for decorative sheets, and excellent post-processing suitability. The present invention provides a decorative sheet comprising a top coat layer having
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention adds a polyol and an isocyanate to produce a urethane bond in the ionizing radiation curable resin, and cures by performing thermal curing and ionizing radiation curing in this order. The polyol has a molecular weight of 10,000 or more and 40,000 or less, a glass transition temperature of 30 ° C. or more and 100 ° C. or less, more preferably a polyol addition amount of 5 wt% or more and 40 wt% or less, It is possible to provide a decorative sheet having a topcoat layer that does not impair the scratch resistance due to the ionizing radiation curable resin, has excellent adhesion, and has excellent post-processability of the decorative sheet in which the decorative sheet and the base material are bonded together. It is said.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0007]
FIG. 1 is a cross-sectional view showing an example of an embodiment according to the present invention, and is a cross-sectional view of a so-called two-layer decorative sheet.
[0008]
As shown in the figure, a top coat layer 6 is applied to a decorative sheet in which a substrate 1 with a transparent or opaque pattern layer 2 and a transparent film 4 as a surface protective layer are bonded together with an adhesive 3. This is an example.
This is an example, and the configuration is not particular about two layers. Even in the so-called single layer pack printing in which the top coat of the present invention is applied to one of the transparent films and the concealing layer and the pattern layer are applied to the other surface. In addition, a method in which a sheet coated with the top coat of the present invention on one side of a transparent film is directly bonded to a wooden substrate via an adhesive without applying a printed pattern, and the pattern of the wooden substrate is used. A single-layer decorative sheet for applying the top coat of the present invention on a substrate on which a pattern is applied may be used.
[0009]
Here, the base sheet 1 is not limited to the material, but specific materials include Japanese paper, craft paper, glassine paper, paperboard, resin impregnated paper, paper such as titanium paper, low density, medium density. Or high density polyethylene, random type, homotype, block type polypropylene, ethylene or propylene α copolymer, ethylene-propylene rubber and propylene kneaded type or cross-linked type olefinic thermoplastic elastomer, isotactic polypropylene and Crosslinking type thermoplastic elastomer with atactic polypropylene, vinyl aromatic compound-conjugated diene compound copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ionomer Of olefinic materials such as Synthetic resin films such as mono- or mixed systems, biaxially stretched polyester, polyester such as non-crystalline polyester (for example, PETA-G from Esterman), polystyrene polyamide, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, acrylic, etc. Furthermore, the synthetic resin film is foamed or porous film, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, acrylonitrile-styrene copolymer rubber, styrene-isoprene-styrene block. Copolymer rubber, styrene-butadiene-styrene block copolymer rubber, rubber such as polyurethane, non-woven fabric, synthetic resin flat yarn and multifilament, natural fiber, synthetic fiber, glass fiber, carbon fiber, There are woven fabrics such as inorganic fibers, metals such as aluminum, iron, nickel, gold, silver and copper, calcium silicate plates, inorganic plates such as cement, and wood plates. Also, a sheet similar to wood obtained by adding paper or wood powder to a recently proposed synthetic resin material may be used.
[0010]
The substrate sheet 1 may be transparent, opaque, or colored with a coloring pigment or the like. In addition to the colorant, UV absorbers, light stabilizers, antioxidants, flame retardants, anti-blocking agents and the like are generally added, and the type is not particularly limited, and the thickness is 30-200 micrometers is common.
[0011]
The pattern layer 2 applied to the base sheet 1 is provided for improving the design, and when ink is used, the binder is nitrified cotton, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyeletane. Acrylic, polyester, chlorinated polyolefin, epoxy, polyamide, etc., alone or in combination, and these modified products can be appropriately selected. These may be water-based, solvent-based, emulsion-based, or solvent-free, and can be arbitrarily selected from a one-component type that does not use a curing agent and a two-component type that uses a curing agent. Further, the curing method is not particularly specified, such as thermal curing, ultraviolet curing, electron beam curing, or the like. Among them, a method of forming urethane by reaction of polyol and isocyanate is common.
[0012]
Examples of the polyol include various glycols, polyether polyols, polyester polyols, acrylic polyols, and modified products thereof, and examples of the isocyanate include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, metaisodiisocyanate, lysine diisocyanate, It can be appropriately selected from isophorone diisocyanate, methylhexane diisocyanate, methylcyclohexanone diisocyanate, trimethylhexamethylene diisocyanate, and the like.
[0013]
In addition to the binder, colorants such as pigments and dyes, extender pigments, solvents, various additives and the like contained in normal ink are added. Particularly frequently used pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica. In addition to the application of the ink, the design can be applied by vapor deposition or sputtering of various metals.
[0014]
Examples of the method for applying the pattern layer 2 include gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, ink jet printing, metal deposition, and sputtering.
[0015]
When the substrate 1 is a substrate having poor adhesion, for example, a polyolefin-based material such as polypropylene, the pattern layer 2 has a corona treatment, ozone treatment, electron beam treatment, ultraviolet treatment, dichromic acid treatment, etc. on the substrate surface. It is desirable to carry out after performing the surface treatment. Furthermore, it is also possible to provide the pattern layer 2 after applying the primer layer on the substrate. Further, in order to improve the concealing property, the concealing layer may be provided with an opaque ink using the same binder as the pattern layer.
[0016]
The transparent film 4 serving as the surface protective layer is bonded to the sheet provided with the pattern layer via the adhesive layer 3, and the film used for these is a synthetic resin in the material used for the substrate. System films are common. In view of recent environmental problems, a polypropylene resin film is most suitable. If necessary, a thermal antioxidant, a flame retardant, an ultraviolet absorber, a light stabilizer, an antiblocking agent, and the like are added to the surface protective film. There are no particular restrictions on the types of these additives, but in the case of flame retardants, halogen-based materials are not preferred in view of recent environmental problems.
[0017]
Moreover, the method of laminating the surface protective layer (transparent film) 4 is also arbitrary. For example, after the surface protective film is produced by an inflation method, an extrusion method, a calendar method, or the like, the substrate 1 provided with the pattern layer 2 is used. And a method of bonding by a dry laminating method or a heat laminating method through an adhesive layer 3, a method of bonding by melting and extruding onto a substrate 1 on which a pattern layer 2 is applied to a resin to be a surface protective layer 4 Etc. In the case of melt extrusion lamination, corona treatment or ozone treatment is usually often performed on the resin extruded from the T die in order to improve adhesion. Furthermore, the method by co-extrusion with adhesive resin is also performed. The thickness of the surface protective layer is usually 30 μm to 200 μm, and the laminate product is generally 60 μm to 400 μm.
[0018]
The surface protective layer 4 can be provided with an embossed pattern 5 in order to improve the design.
[0019]
The top coat layer 6 is provided on the decorative sheet obtained as described above in order to improve the surface performance and design properties such as scratch resistance, antibacterial properties, and stain resistance. It relates to the composition of the top coat.
[0020]
The first requirement of the present invention is that the ionizing radiation curable resin having excellent scratch resistance is post-processability such as V-cutting of the decorative board, and further, the cured film and the surface are prevented from being whitened or cracked. In order to introduce a urethane skeleton for improving the adhesion with the protective layer 4, a polyol and an isocyanate are added.
[0021]
The second requirement of the present invention is that the added polyol has a molecular weight of 10,000 or more and 40,000 or less and a glass transition point of 30 ° C. or more and 100 ° C. or less.
Here, when the molecular weight is 10,000 or less, although the ionizing radiation curable resin is present, the touch drying time after the top coat application is long, and blocking tends to occur in a normal production line. On the other hand, when the molecular weight is 40,000 or more, the feeling of grip and gloss of the coating film are lowered. On the other hand, when the glass transition point is 30 ° C. or lower, although the ionizing radiation curable resin exists, the urethane produced from the polyol and the isocyanate is too soft and has poor scratch resistance. On the other hand, when the glass transition point is 100 ° C. or higher, the urethane produced is too hard, and it becomes impossible to suppress whitening or cracking during post-processing of the decorative board.
[0022]
The third requirement of the present invention is that the amount of polyol to be added is 5% by weight to 40% by weight. That is, if it is 5% by weight or less, improvement in post-workability and adhesion, which are the effects of addition, cannot be expected, while if it is 40% by weight or more, the scratch resistance of the ionizing radiation curable resin is impaired.
[0023]
The polyol used here can be arbitrarily selected from various polyether-based polyols, polyester-based polyols, acrylic polyols, and epoxy-based polyols that satisfy the molecular weight and glass transition point. Either of these is acceptable.
[0024]
Isocyanate to react with polyol to form urethane bond can be selected from tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, lysine isocyanate, metadiisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, etc. However, it is common to use hexamethylene diisocyanate considering that weather resistance is required.
[0025]
Next, the ionizing radiation curable resin that is the main component of the top coat can be appropriately selected from either an electron beam curable resin or an ultraviolet curable resin to which an ultraviolet initiator is added. As the electron beam curable resin, a monomer is mixed as necessary with a prepolymer or oligomer having a polymerizable unsaturated bond or epoxy group in the molecule. Prepolymers and oligomers include unsaturated polyesters, polyester methacrylates, polyether matacrylates, melamine methacrylates, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, and melamine acrylates, and monomers include styrene. Are appropriately selected from, for example, an acrylic ester system, a methacrylic acid ester system, an unsaturated substituted substituted amino alcohol ester system, an unsaturated carboxylic acid amide system, and a polythiol system, and used alone or in a mixture thereof.
[0026]
Even when an ultraviolet curable resin is used, the resin composition is the same as the prepolymer, oligomer and monomer described above, and there is no problem. However, a photopolymerization initiator is required for curing with ultraviolet rays. Photopolymerization initiators include acetophenones, benzophenones, benzoyl benzoates and the like that are commonly used, but there is no particular limitation on the selection thereof, and it can be arbitrarily selected.
[0027]
The top coat can optionally contain additives as long as the requirements of the present invention are satisfied. In order to improve the weather resistance, it is possible to add the same ultraviolet absorber and light stabilizer as those added to the surface protective layer. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, triazine-based, selenium oxide, titanium oxide, and other inorganic materials, and examples of light stabilizers include hindered amine-based and amino ether-based materials. There is also a type that crosslinks with a top coat resin as described in patent publications “JP-A-7-90184, JP-A-8-151415, JP-A-10-298493” of Otsuka Chemical Co., Ltd. The amounts of the ultraviolet absorber and the light stabilizer are each suitably in the range of 0.1% to 20%.
[0028]
In addition, functional additives such as antibacterial agents and fungicides are optionally added to impart functions. Aluminum oxide, silicon oxide, silicon nitride, silicon carbide, boron nitride, boron carbide, glass beads, etc. may be added to adjust the gloss from the design of the surface and further improve the wear resistance.
[0029]
The film thickness of these top coats is preferably 2 μm to 50 μm because it is difficult to adjust gloss when the thickness is 2 μm or less, and there is no cost advantage when the thickness is 50 μm or more.
Moreover, since the polyol and isocyanate are added to the ionizing radiation curable resin, the topcoat curing method is a combination of electron beam or ultraviolet curing and thermal curing. Usually, after top coat application, the polyol and isocyanate are first reacted to produce urethane, followed by ionizing ray curing.
[0030]
[Action]
As described above, the decorative sheet of the present invention is obtained by adding a polyol and an isocyanate to an ionizing ray curable resin for top coat, preferably having a molecular weight of 10000 to 40000, a glass transition point of 30 ° C. to 100 ° C., and By regulating the addition amount to 5 wt% to 40 wt%, the post-processability of the decorative board is ensured without impairing the scratch resistance characteristic of the ionizing ray curable resin, and the topcoat cure shrinkage. It was possible to provide a decorative sheet that was suppressed and excellent in adhesion.
[0031]
【Example】
Hereinafter, the present invention will be described based on examples.
[0032]
<Example 1>
After corona treatment is performed on both sides of a colored high-density polyethylene base material (FZ92103: manufactured by Riken Vinyl Industry Co., Ltd.) having a thickness of 80 μm, 5% by weight of silicon oxide and 105% by weight of barium sulfate are added to one side. A two-component urethane primer (Lamister Medium: manufactured by Toyo Ink Manufacturing Co., Ltd.) is applied by gravure coating to a thickness of 1 μm, and the two-component urethane ink (Lamistor: manufactured by Toyo Ink Manufacturing Co., Ltd.) is applied to the opposite surface. Was used to produce a substrate sheet with a pattern by gravure printing.
Separately from this, a random type polypropylene (F327: Grande) to which 2000 ppm of benzotriazole-based UV absorber (Tinuvin 328: manufactured by Ciba Specialty Chemicals) and 2000 ppm of hindered amine light stabilizer (Kimasoap 944: manufactured by Ciba Specialty Chemicals) was added. (Manufactured by Polymer Co., Ltd.) was extruded with an extruder to a thickness of 80 μm to obtain a transparent surface protective layer.
Through the adhesive (AD806: manufactured by Toyo Morton Co., Ltd.), the substrate with the pattern and the surface protective layer thus obtained were coated on the pattern surface of the substrate sheet with the pattern to a thickness of 5 μm. After pasting together by dry lamination, embossing of the wood grain conduit pattern was applied by hot pressure to produce a decorative sheet with an embossed pattern.
On the above sheet, an ultraviolet curable resin (Seika Beam P1520: manufactured by Dainichi Seika Co., Ltd.) 80% by weight, an acrylic polyol (A-801: manufactured by Dainippon Ink and Chemicals) 18% by weight with a molecular weight of 20000 and a glass transition point of 70 ° C. A resin added with 2% by weight of hexamethylene diisocyanate (Dismodule K-5-2333: manufactured by Bayer) was gravure coated to a thickness of 5 μm, dried with hot air at 40 ° C., and then applied to a high-pressure mercury lamp. A decorative sheet provided with a top coat layer was obtained by irradiation with ultraviolet rays.
[0033]
<Comparative Example 1>
Only the ultraviolet curable resin used in Example 1 was applied to the decorative sheet before providing the top coat layer obtained in Example 1, and ultraviolet light was irradiated to obtain a decorative sheet with a top coat.
[0034]
<Comparative example 2>
The topcoat-coated makeup obtained by applying the resin mixed with acrylic polyol and isocyanate used in Example 1 to the decorative sheet not coated with the topcoat obtained in Example 1, and drying and curing with warm air. A sheet was obtained.
[0035]
<Test evaluation>
After pasting the decorative sheets obtained in Examples and Comparative Examples to a wooden substrate using a urethane-based adhesive, the surface scratch resistance is pencil hardness, and the top coat adhesion is a cellophane cellophane tape peel test. The post-workability was evaluated by a V-cut test. The results are shown in Table 1.
[0036]
[Table 1]

[0037]
【The invention's effect】
Since this invention is the above structure, there exist the following effects.
That is, it has become possible to provide a decorative sheet that has excellent adhesion without impairing the excellent scratch resistance of the UV-effect resin, and excellent post-processability after V-cutting and lapping of the decorative board. .
[Brief description of the drawings]
FIG. 1 is an explanatory view showing, in section, a decorative sheet provided with a top coat according to an embodiment of the present invention.
[Explanation of symbols]
1 ...... Base layer 2 ...... Picture layer 3 ...... Adhesive layer 4 ...... Surface protective layer (transparent film)
5 …… Embossed pattern 6 …… Topcoat layer

Claims (3)

Applying a topcoat layer made of a resin composition to which a polyol and an isocyanate having a molecular weight of 10,000 to 40,000 and a glass transition point of 30 ° C. or more and 100 ° C. or less are added to an ionizing radiation curable resin; A method for producing a decorative sheet, comprising: a step of thermally curing a topcoat layer comprising a resin composition; and a step of ionizing radiation-curing the topcoat layer in this order .   The method for producing a decorative sheet according to claim 1, wherein 5 to 40 wt% of the polyol is added to the topcoat layer.   A method for producing a decorative board having V-cut suitability, comprising a step of bonding a decorative sheet produced by the production method according to claim 1 or 2 and a substrate.

Images