JP2023065819A - Decorative sheet - Google Patents

Abstract

To provide a decorative sheet capable of reducing the occurrence of delamination.SOLUTION: A decorative sheet 10 comprises a base material 11, a pattern layer 12, an adhesive layer 13, a transparent resin layer 14, and a surface protection layer 15 in this order. The adhesive layer 13 comprises an acrylic resin and an isocyanate curing agent as a cross-linking component. The acrylic resin is composed of (a) at least one monofunctional acrylic ester monomer with a carbon number of 4 or less and a homopolymer glass transition temperature of 0°C or lower, (b) at least one monofunctional acrylic ester monomer with a carbon number of 8 or more, and (c) at least one monofunctional acrylic ester monomer with hydroxyl groups, and has a property ranged in which (a) accounts for half or more of the total mass of the monomer, with a glass transition temperature in the range of -45 to -10°C, and with a hydroxyl group value in the range of 40 mg KOH/g or more and 200 mg KOH/g or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a decorative sheet.

In general, steel plates, etc., are used for building interior and exterior materials such as walls, ceilings, floors, and entrance doors, as well as fittings and fixtures such as window frames, doors, handrails, baseboards, rims, and malls. A metal member, a resin member, or a wooden member is used as an adherend, and a decorative sheet is adhered to the adherend.
Many of the decorative sheets are laminates, and in particular, decorative sheets used for building exteriors, bathrooms, etc. have the problem of delamination due to moisture entering from the edges of the decorative sheet toward the inside of the decorative sheet. There is

When manufacturing a decorative sheet, which is generally a laminate, an adhesive layer may be provided. Acrylic resin, polyurethane resin, epoxy resin, and polyester resin are generally used for this adhesive layer (Patent Document 1). In that case, delamination may occur between the adhesive layer and the transparent resin layer formed on the adhesive layer.

Japanese Patent No. 4737722

An object of the present invention is to provide a decorative sheet that can reduce the occurrence of delamination (especially the occurrence of delamination between an adhesive layer and a transparent resin layer) in order to solve the above problems. .

As a result of intensive studies, the present inventors have found that a decorative sheet using a resin containing specific elements in an adhesive layer (also called an anchor layer or an anchor coat layer) can achieve the above-mentioned objectives of the present invention. reached.
In order to solve the above problems, a decorative sheet according to one aspect of the present invention comprises a polyolefin base material, a pattern layer, an anchor coat layer, a transparent resin layer containing polypropylene as a main component, and a top coat layer. A decorative sheet provided in order, wherein the anchor coat layer is composed of an acrylic resin and an isocyanate curing agent as a cross-linking component,
The acrylic resin comprises (a) at least one monofunctional acrylate monomer having 4 or less carbon atoms and a homopolymer glass transition temperature of 0° C. or less, and (b) monofunctional acrylic acid having 8 or more carbon atoms. At least one ester monomer and (c) at least one monofunctional acrylic acid ester monomer having a hydroxyl group are used, and (a) accounts for more than half of the total mass of the monomers, and the glass transition temperature is − The temperature is within the range of 45 to −10° C., and the hydroxyl value is in the range of 40 mgKOH/g or more and 200 mgKOH/g or less.

According to one aspect of the present invention, there is provided a decorative sheet capable of reducing the occurrence of delamination (in particular, the occurrence of delamination between an adhesive layer and a transparent resin layer).

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the cross-section of the decorative sheet which concerns on embodiment of this invention.

[Configuration of decorative sheet]
A configuration of a decorative sheet according to one embodiment of the present invention will be described with reference to the drawings.
Here, the configuration shown in FIG. 1 is a schematic one, and the relation between the thickness and the planar dimension, the ratio of the thickness of each layer, and the like are different from the actual one. Further, the embodiments shown below are examples of configurations for embodying the technical idea of the present invention. It is not limited to things. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

FIG. 1 is a cross-sectional view showing the configuration of a decorative sheet 10 according to this embodiment. The decorative sheet 10 includes a substrate (polyolefin substrate) 11, a pattern layer 12 formed on the substrate 11, an adhesive layer (anchor coat layer) 13 formed on the pattern layer 12, and and a surface protective layer (topcoat layer) 15 formed on the transparent resin layer 14 . Hereinafter, as the present embodiment, a decorative sheet 10 in which a transparent resin layer 14 is bonded to a base material 11 printed with a pattern layer 12 via an adhesive layer 13, and a surface protective layer 15 is further provided will be described with reference to FIG. do.

(adhesive layer)
The adhesive layer 13 is a layer provided to bond the pattern layer 12 and the transparent resin layer 14 together.
The adhesive layer 13 is made of an acrylic resin, and is formed using an ordinary coating method such as gravure coating, micro gravure coating, comma coating, knife coating, and die coating.
The acrylic resin constituting the adhesive layer 13 includes (a) at least one monofunctional acrylate monomer having 4 or less carbon atoms and a homopolymer having a glass transition temperature of 0° C. or less, and (b) 8 or more carbon atoms. and (c) at least one monofunctional acrylate monomer having a hydroxyl group, and (a) accounts for more than half of the total mass of the monomers. The resin has a glass transition temperature in the range of −45 to −10° C. and a hydroxyl value in the range of 40 mgKOH/g or more and 200 mgKOH/g or less.
By adding an appropriate amount of a curing agent such as isocyanate to this, the adhesive layer 13 can be cured.

At least one of ethyl acrylate, normal propyl acrylate, normal butyl acrylate, isobutyl acrylate, and the like can be used as the acrylic acid ester monomer having 4 or less carbon atoms that constitutes the acrylic resin of the present embodiment. These acrylic acid ester monomers have a low glass transition temperature and exhibit appropriate tackiness. Therefore, the progress of cross-linking by the isocyanate curing agent while the transparent resin layer 14 is floating can be prevented, and the pattern can be uniformly formed. Adhesion between the layer 12 and the transparent resin layer 14 can be provided.

At least one of octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, and the like can be used as the acrylic acid ester monomer having 8 or less carbon atoms that constitutes the acrylic resin of the present embodiment. Since these acrylic acid ester monomers have the effect of lowering the polarity when blended, they have good compatibility with the transparent resin layer 14 and can improve adhesion. The improved adhesion between the transparent resin layer 14 and the adhesive layer 13 makes it difficult for water to enter the gap between the layers, and an improvement in moisture resistance can also be expected.

At least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, and the like can be used as the acrylic acid ester monomer having a hydroxyl group that constitutes the acrylic resin of the present embodiment. By using these acrylic acid ester monomers, hydroxyl groups can be imparted to the acrylic resin. Due to the presence of hydroxyl groups, cross-linking with a curing agent is possible, and an improvement in adhesion, as well as an improvement in moisture resistance and heat resistance can be expected.

Further, the glass transition temperature of the acrylic resin of the present embodiment may be −45° C. or higher, preferably −30° C. or higher. The glass transition temperature is preferably -10°C or lower, more preferably -15°C or lower. If the glass transition temperature is lower than −45° C., the adhesion between the picture layer and the transparent resin layer before cross-linking is insufficient due to lack of tackiness due to the small cohesive force of the acrylic resin, resulting in uneven adhesion. If the glass transition temperature is higher than −10° C., there is no tack due to the high cohesive force of the acrylic resin, resulting in poor adhesion.

Moreover, the hydroxyl value of the acrylic resin of the present embodiment is preferably 40 mgKOH/g or more, more preferably 80 mgKOH/g or more. The hydroxyl value is preferably 200 mgKOH/g or less, more preferably 160 mgKOH/g or less. If the hydroxyl value is less than 40 mgKOH/g, the reaction with the curing agent added to increase the crosslink density of the acrylic resin may not proceed. On the other hand, if the hydroxyl value exceeds 200 mgKOH/g, the water resistance may be lowered, or the pot life may be shortened due to excessively high reactivity with the cross-linking agent.

The curing agent used for curing the acrylic resin of the present embodiment is not particularly limited. It can be appropriately selected and used from commercially available curing agents including hydrogenated products.

Further, the ultraviolet absorber (UVA) having a triazine skeleton added to the acrylic resin of the present embodiment is, for example, 2,4-Bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)- 1,3,5-triazine, 2-(2-Hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, Ethylhexyl Triazone, 2-(2,4-Dihydroxyphenyl)-4,6 -diphenyl-1,3,5-triazine, 2,4,6-Tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine, N,N',N''-Tri(m-tolyl )-1,3,5-triazine-2,4,6-triamine, 2-(2,4-Dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2 ,4,6-Tris(2,4-dihydroxyphenyl)-1,3,5-triazine, Bemotrizinol and the like can be appropriately selected and used.
UVA with a triazine skeleton is expected to have strong absorption, long-term durability, and excellent heat resistance compared to UVA without a triazine skeleton.

Further, the light stabilizer (HALS) having a NOR-type skeleton added to the acrylic resin of the present embodiment is Decanedioic acid, bis (2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester, reaction products with 1,1-dimethylethylhydroperoxide and octane, 2,4-bis [N-Butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidic-4-yl)amino]-6-(2- It can be appropriately selected from hydroxyethylamine)-1,3,5-triazine and the like. Since HALS having a NOR-type skeleton has low basicity, there is no concern that reaction will occur even if it is added to a paint containing an acid-containing catalyst or resin.

The method of joining the transparent resin layer 14 to the base material 11 provided with the pattern layer 12 may be through the adhesive layer 13, for example, using various lamination methods such as heat lamination, extrusion lamination, dry lamination, and sand lamination. be able to.

(Base material)
As the resin constituting the base material 11, that is, the resin component, polyolefin or polyester is preferably used, and polyolefin is most preferable from the viewpoint of versatility. The resin constituting the base material 11 can be arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Materials other than the above polyolefin resins include α-olefins (e.g., 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, , 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene , 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene , 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.), homopolymerization or copolymerization of two or more types, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, Vinyl alcohol copolymer, ethylene/methyl methacrylate copolymer, ethylene/ethyl methacrylate copolymer, ethylene/butyl methacrylate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, ethylene/butyl acrylate Examples thereof include those obtained by copolymerizing ethylene or α-olefin with other monomers, such as copolymers.

The base material 11 may be subjected to surface treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, dichromic acid treatment, etc., in order to enhance adhesion with adjacent layers. Furthermore, a primer layer (not shown) may be provided between the substrate 11 and the pattern layer 12 to ensure close contact.
If the substrate 11 is made of polyolefin or polyester, the adhesiveness with the pattern layer 12 described later is ensured, and if it is made of polyolefin, the adhesiveness with the pattern layer 12 is further assured. .

When it is desired to impart concealability to the decorative sheet 10, a concealable colored sheet may be used as the base material 11, or a concealing layer (not shown) may be used as the upper layer of the base material 11 and the lower layer of the pattern layer 12. ) may be provided. When a colored sheet is used as the base material 11, a coloring agent can be added to the resin material forming the base material 11 for coloring. Examples of the coloring agent include inorganic pigments (titanium oxide, carbon black, etc.), organic pigments (phthalocyanine blue, etc.), and dyes. One or two or more of known or commercially available colorants can be selected and used as the colorant of the present embodiment, and the amount added can be adjusted so as to obtain the desired concealing properties and design properties. .
In addition, if necessary, the base material 11 may contain, for example, a filler, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, a crystal nucleating agent, an ultraviolet absorber, a light stabilizer, a heat stabilizer, Various additives such as coloring agents and matting agents may be added.

(picture layer)
The pattern layer 12 is, for example, a layer including a pattern printed on the base material 11 using ink. The ink used to form the pattern layer 12 may contain, for example, a binder resin. The binder resin contained in the ink used to form the pattern layer 12 is, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc. alone or in each modified product. can be appropriately selected and used from. Further, they may be water-based, solvent-based, or emulsion-type, and may be one-liquid type or two-liquid type using a curing agent. In this embodiment, as the ink used for forming the pattern layer 12, a water-based colored ink is suitable from the viewpoint of coatability.
As a method of curing the ink used for forming the pattern layer 12, for example, a method of curing the ink by irradiation with ultraviolet rays, electron beams, or the like can be mentioned. Among them, the most common method is to use urethane-based ink and to cure it with polyisocyanate.

The ink used to form the pattern layer 12 includes, in addition to the binder resin described above, various additives such as pigments, dyes, and other coloring agents, extender pigments, solvents, light stabilizers, and the like, which are contained in ordinary inks. may be added. Examples of highly versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.
The method of providing the pattern layer 12 is not particularly limited, and ordinary printing methods such as gravure printing, offset printing, screen printing, flexographic printing, and ink jet printing can be used.

(Transparent resin layer)
Polyolefin is preferably used as the material of the transparent resin layer 14. Examples include polypropylene, polyethylene, polybutene, and various α-olefin copolymers (propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.). polymer) is used. Among these resins, polypropylene is the most preferable material for the transparent resin layer 14 .
The transparent resin layer 14 of the present embodiment may be a sheet formed by film formation, or may be a laminate of already formed sheets. The transparent resin layer 14 may be made of, for example, a highly crystalline polypropylene resin.

The transparent resin layer 14 preferably comprises polypropylene in an amount of 80% by mass or more of the entire mass, more preferably 90% by mass or more. The “transparent resin layer containing polypropylene as a main component” means a state in which polypropylene accounts for 80% by mass or more of the entire mass of the transparent resin layer 14 .

In the transparent resin layer 14, if necessary, for example, a heat stabilizer, a flame retardant, an ultraviolet absorber, a light stabilizer, an antiblocking agent, a catalyst scavenger, and as long as the features of the present embodiment are not impaired, For example, various additives such as colorants, light scattering agents and gloss modifiers may be added.
Examples of heat stabilizers include phenol, sulfur, phosphorus, hydrazine, etc. Flame retardants include aluminum hydroxide, magnesium hydroxide, etc. UV absorbers include benzotriazole, benzoate, and the like. Benzophenone-based, triazine-based light stabilizers, for example, hindered amine-based light stabilizers, are generally added in any combination.

A method for producing the transparent resin layer 14 is not particularly limited, and for example, a normal method such as calendar film formation or extrusion film formation can be used.
The transparent resin layer 14 may be provided with surface unevenness, so-called embossing, in order to impart designability. Examples of the method of providing unevenness include a method of subjecting the transparent resin layer 14 to heat embossing after extrusion molding, and a method of performing embossing simultaneously with extrusion molding using a cooling roll provided with unevenness during extrusion. More specifically, the uneven pattern (embossed pattern) is directly imparted to the transparent resin layer 14, for example, a highly crystalline polypropylene sheet, and the method is an embossing plate having an uneven pattern by applying heat and pressure to the polypropylene sheet formed into a film. and a method of providing embossing at the same time as cooling using a cooling roll having an uneven pattern when forming a film using an extruder. In this case, it is also possible to fill the recesses of the uneven pattern with colored ink to further improve the design.

The uneven pattern may be provided if necessary, and may not be provided if unnecessary.
Also, one side or both sides of the transparent resin layer 14 may be activated by, for example, corona treatment, plasma treatment, electron beam treatment, ultraviolet treatment, dichromic acid treatment, or the like, if necessary.

(Surface protective layer)
The surface protective layer 15 according to this embodiment is a layer provided to the decorative sheet 10 to provide functions such as weather resistance, scratch resistance, stain resistance, and design. The material forming the surface protective layer 15 is not particularly limited, and can be appropriately selected from, for example, resin materials such as urethane, acrylic, acrylic silicon, fluorine, and epoxy resins.

Ink containing urethane polymer as a main component is suitable for the material of the surface protective layer 15 from the viewpoint of coatability. Here, "ink containing urethane polymer as a main component" means a state in which the urethane polymer accounts for 80% by mass or more of the total mass of the ink.
In the present embodiment, the urethane-based surface protective layer 15 using an isocyanate reaction is desirable from the viewpoints of workability, cost, cohesive strength of the resin itself, and the like.

In forming the surface protective layer 15, examples of the isocyanate include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), and isophorone diisocyanate. (IPDI), bis(isocyanatomethyl)cyclohexane (HXDI), trimethylhexamethylene diisocyanate (TMDI) derivatives such as adducts, burettes, isocyanurates and curing agents such as various prepolymers. can be done.

The surface protective layer 15 may optionally contain various additives such as ultraviolet absorbers, heat stabilizers, light stabilizers, antiblocking agents, catalyst scavengers, colorants, light scattering agents, and gloss modifiers. may be blended. Among these, for example, at least one of an ultraviolet absorber and a light stabilizer is preferably contained.

The method of forming the surface protective layer 15 is not particularly limited, and the above-mentioned material is applied as a coating liquid by a usual method such as gravure coating, micro gravure coating, comma coating, knife coating, and die coating. After that, the surface protective layer 15 may be formed by curing by a method suitable for the material, such as heat curing or ultraviolet curing.
Also, the surface protective layer 15 may be provided after the pattern layer 12 formed on the base material 11 and the transparent resin layer 14 are bonded via the adhesive layer 13 .

(primer layer)
The decorative sheet 10 according to this embodiment may further include a primer layer 16 on the back surface of the substrate 11 opposite to the pattern layer 12 side.
The primer layer 16 may be made of the same component as the binder resin contained in the colored ink for forming the pattern layer 12 .

The method of forming the primer layer 16 is not particularly limited. Alternatively, the primer layer 16 may be formed by curing by a method suitable for the material, such as heat curing or ultraviolet curing.

Further, the primer layer 16 may be provided after forming a laminate including the substrate 11, the pattern layer 12, the adhesive layer 13, the transparent resin layer 14, and the surface protective layer 15 in this order. After providing the primer layer 16 on the back surface of the material 11, the substrate 11 provided with the primer layer 16, the pattern layer 12, the adhesive layer 13, the transparent resin layer 14, and the surface protective layer 15 are provided in this order. Laminates may be formed.

Considering that the back surface of the decorative sheet is wound up in a web form, the primer layer 16 should contain silica, alumina, magnesia, etc., in order to avoid blocking and enhance adhesion to the adhesive. , titanium oxide, barium sulfate, and other inorganic fillers may be added.

Regarding the thickness of each layer constituting the decorative sheet 10 according to the present embodiment, it is desirable that the thickness of the base material 11 is in the range of 50 μm or more and 100 μm or less in consideration of printing workability, cost, etc., and the pattern layer 12 is 1 μm. The thickness of the adhesive layer 13 is preferably in the range of 1 μm to 3 μm, the transparent resin layer 14 is preferably in the range of 70 μm to 100 μm, and the surface protective layer. 15 is preferably in the range of 3 μm or more and 15 μm or less. Further, the thickness of the adhesive layer 13 is more preferably in the range of 1 μm to 2.5 μm, more preferably in the range of 1.5 μm to 2 μm, in consideration of hydrolysis resistance, printing workability, cost, etc. It is more desirable to

In addition, when the thickness of each layer is less than each lower limit mentioned above, the function (performance) of each layer may not be obtained. In addition, when the thickness of each layer exceeds each upper limit described above, the function (performance) of each layer does not improve so much, so setting the thickness of each layer to each upper limit or less is preferable from the viewpoint of manufacturing cost.

Moreover, when the primer layer 16 is provided, the thickness of the primer layer 16 is preferably in the range of 1 μm or more and 5 μm or less. If the thickness of the primer layer 16 is within the above numerical range, the function (performance) of the primer layer 16 can be reliably exhibited.
Also, the total thickness of the decorative sheet 10 is preferably within the range of 125 μm to 240 μm.
Within the above numerical range, the printing workability can be easily improved, and the manufacturing cost can be reduced.

The peel strength between the adhesive layer 13 and the transparent resin layer 14 in the decorative sheet 10 according to this embodiment is preferably 15 N/inch or more. If the peel strength between the adhesive layer 13 and the transparent resin layer 14 is 15 N/inch or more, it is possible to reliably prevent roll misalignment when the decorative sheet 10 is produced in a roll form.
Moreover, it is preferable that the peel strength between the adhesive layer 13 and the transparent resin layer 14 after the decorative sheet 10 is exposed to an environment of 40° C. and 90% RH for 500 hours is 10 N/inch or more. If the peel strength between the adhesive layer 13 and the transparent resin layer 14 after exposing the decorative sheet 10 to an environment of 40° C. and 90% RH for 500 hours is 10 N/inch or more, the decorative sheet 10 has excellent durability. You can give it character.

In addition, the decorative sheet 10 was tested with a super xenon tester (Atlas Weatherometer Ci4000 manufactured by Toyo Seiki Co., Ltd.) under test conditions of 180 W light irradiation, 12 minutes rain/120 minutes cycle, and 24 hours. If the peel strength between layers is 10 N/inch or more, the decorative sheet can be provided with excellent weather resistance, and the decorative sheet can be used outdoors.

In addition, the peel strength in this embodiment can be determined, for example, by the delamination test described below.

<Delamination test>
In the decorative sheet 10 with the adhesive layer 13 having a thickness of 10 μm, a test (interlaminar delamination test) is conducted to determine whether or not the adhesive layer 13 and the transparent resin layer 14 are peeled off.
After the cellophane tape made by Nichiban was crimped onto the surface of the decorative sheet 10, it was strongly peeled off with a certain force (for example, 5 N/inch, 10 N/inch, 15 N/inch, 20 N/inch) to form the adhesive layer 13 and the transparent resin layer 14. The presence or absence of peeling between and is evaluated with a microscope. In the present embodiment, the maximum force at which peeling does not occur between the adhesive layer 13 and the transparent resin layer 14 is defined as "peel strength".

The measurement of the peel strength in the present embodiment is not limited to the above method, and for example, a T-shaped peel test between the adhesive layer 13 and the transparent resin layer 14 in accordance with JIS K6854-3: 1999. may be performed to measure (determine) the peel strength between the adhesive layer 13 and the transparent resin layer 14 .

[Method for manufacturing decorative sheet]
A method for manufacturing the decorative sheet 10 according to one embodiment of the present invention will be briefly described below.
First, the pattern layer 12 is formed with a thickness of 1 μm to 5 μm on the substrate 11 which is a polyolefin substrate having a thickness of 50 μm or more and 100 μm or less with a colored ink using a urethane polymer as a binder.
Next, on the pattern layer 12, at least an acrylic resin as a resin component and an isocyanate curing agent as a cross-linking component are formed. and at least one acrylic ester monomer having 8 or more carbon atoms and at least one acrylic ester monomer having a hydroxyl group, and having a glass transition temperature in the range of -45 to -10 ° C. An adhesive layer 13 made of a resin having a hydroxyl value in the range of 40 mgKOH/g to 200 mgKOH/g is formed with a thickness of 1 μm to 3 μm.

Next, a transparent resin layer 14 mainly composed of polypropylene is formed on the adhesive layer 13 by extrusion molding with a thickness of 70 μm or more and 100 μm or less.
Finally, on the transparent resin layer 14, a surface protective layer 15 is formed with a film thickness of 3 μm or more and 15 μm or less using ink containing urethane polymer as a main component.
Thus, the decorative sheet 10 according to this embodiment is manufactured.

After forming the pattern layer 12 and before forming the adhesive layer 13, the surface of the pattern layer 12 on the adhesive layer 13 side may be surface-treated so that the wetting index is 60 dyne or more. .
In addition, the colored ink used in the step of forming the pattern layer 12 may contain a binder resin. A primer layer 16 made of the same component as the binder resin and having a film thickness within the range of 1 μm or more and 5 μm or less may be formed.

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

<Example 1>
As shown in Table 1, 85 parts of EA (manufactured by Kanto Kagaku Co., Ltd.) as an acrylic ester monomer having 4 or less carbon atoms and an acrylic ester monomer having a hydroxyl group were placed in a reaction vessel with branches for a personal synthesis apparatus (manufactured by Tokyo Rikaki). 10 parts of HEA (manufactured by Kanto Chemical Co., Ltd.), 5 parts of LA (manufactured by Kanto Chemical Co., Ltd.) as an acrylic acid ester monomer having 8 or more carbon atoms, and AIBN (polymerization initiator) to the monomer 1 mol% of the monomer , the solvent was added so that the monomer mass was 30 wt %. After bubbling argon at room temperature for 15 minutes, the mixture was heated and stirred at 70°C for 8 hours in a closed system to prepare an acrylic resin having a glass transition temperature of -19°C and a hydroxyl value of 48 mgKOH/g. The glass transition temperature of "EA" is -20°C.

A pattern layer (thickness: 3 μm) was formed by gravure-printing a wood grain pattern using a two-liquid type urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) on a masking polyethylene raw fabric (thickness: 70 μm). This two-component urethane ink is an ink containing a binder resin.
A mixture of the acrylic resin and 1.2 equivalents of the isocyanate curing agent Duranate TSE-100 (Asahi Kasei) is applied to the substrate thus obtained to form an adhesive layer (anchor coat layer: thickness 2 μm). bottom.
Through this adhesive layer, the substrate and the transparent polyolefin resin forming the transparent resin layer were dry-laminated. The film thickness of the transparent resin layer was set to 80 μm.

Furthermore, as a surface protective layer, a two-liquid curing polyurethane resin layer composed of acrylic polyol (a copolymer of methyl methacrylate and 2-hydroxy methacrylate) and a curing agent (a nurate form of hexamethylene diisocyanate) is applied onto the transparent polyolefin resin. Formed (layer thickness 8 μm) to obtain a decorative sheet of Example 1.

<Example 2>
75 parts of EA (manufactured by Kanto Chemical Co., Ltd.) and 20 parts of HEA (manufactured by Kanto Chemical Co., Ltd.) used in Example 1 were used to obtain an acrylic resin having a glass transition temperature of −18° C. and a hydroxyl value of 97 mgKOH/g. A decorative sheet of Example 2 was obtained in the same manner as in Example 1 except for the above.

<Example 3>
65 parts of EA (manufactured by Kanto Chemical Co., Ltd.) and 30 parts of HEA (manufactured by Kanto Chemical Co., Ltd.) used in Example 1 were used to obtain an acrylic resin having a glass transition temperature of −18° C. and a hydroxyl value of 145 mgKOH/g. A decorative sheet of Example 3 was obtained in the same manner as in Example 1 except for the above.

<Example 4>
55 parts of EA (manufactured by Kanto Kagaku Co., Ltd.) and 40 parts of HEA (Kanto Kagaku) used in Example 1 were used, except that an acrylic resin having a glass transition temperature of -17 ° C. and a hydroxyl value of 193 mgKOH / g was used. A decorative sheet of Example 4 was obtained in the same manner as in Example 1.

<Example 5>
A decorative sheet of Example 5 was obtained in the same manner as in Example 1, except that Tinvin 479 was added as a triazine-based ultraviolet absorber to the acrylic resin prepared in Example 3.

<Example 6>
A decorative sheet of Example 6 was obtained in the same manner as in Example 1, except that Tinvin479 as a triazine-based ultraviolet absorber and Tin123 as a NOR-type light stabilizer were added to the acrylic resin prepared in Example 3.

<Example 7>
A decorative sheet of Example 7 was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer (anchor coat layer) in Example 1 was changed to 5 μm.

<Example 8>
The cosmetic of Example 8 was prepared in the same manner as in Example 1 except that Acrydic FL-638-BE (acrylic resin manufactured by DIC Corporation) was used as the material for the surface protective layer (topcoat layer) in Example 1. got a sheet.

<Comparative Example 1>
Comparative Example 1 in the same manner as in Example 1 except that the addition of LA (manufactured by Kanto Chemical Co., Ltd.) used in Example 1 was eliminated and an acrylic resin having a glass transition temperature of -18 ° C. and a hydroxyl value of 169 mgKOH / g was used. I got a cosmetic sheet of

<Comparative Example 2>
Same as Example 1 except that EA (manufactured by Kanto Kagaku Co., Ltd.) used in Example 1 was changed to n-BA (Kanto Kagaku) and an acrylic resin having a glass transition temperature of -49 ° C. and a hydroxyl value of 48 mgKOH / g was used. A decorative sheet of Comparative Example 2 was obtained by the method of .

<Comparative Example 3>
Same as Example 1 except that EA (manufactured by Kanto Kagaku Co., Ltd.) used in Example 3 was changed to t-BA (Kanto Kagaku) and an acrylic resin having a glass transition temperature of -9 ° C. and a hydroxyl value of 145 mgKOH / g was used. A decorative sheet of Comparative Example 3 was obtained by the method of .

<Comparative Example 4>
90 parts of EA (manufactured by Kanto Kagaku Co., Ltd.) and 5 parts of HEA (Kanto Kagaku) used in Example 1 were used, except that an acrylic resin having a glass transition temperature of -18 ° C. and a hydroxyl value of 24 mgKOH / g was used. A decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 1.

<Comparative Example 5>
50 parts of EA (manufactured by Kanto Chemical Co., Ltd.) and 45 parts of HEA (manufactured by Kanto Chemical Co., Ltd.) used in Example 1 were used to obtain an acrylic resin having a glass transition temperature of −17° C. and a hydroxyl value of 217 mgKOH/g. A decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 1 except for the above.

<Comparative Example 6>
A decorative sheet of Comparative Example 6 was obtained in the same manner as in Example 1 except that the isocyanate curing agent used in Example 1 was changed to the epoxy curing agent Denacol EX-830 (Nagase Chemtech).

<Evaluation>
For the decorative sheets obtained in the above Examples and Comparative Examples, the peel strength (N/inch) and the peel strength (N/inch) after exposure for 500 hours in a 90% RH environment were measured and evaluated by the following methods. . Table 1 shows the evaluation results. In Table 1, "EA" is "ethyl acrylate", "LA" is "lauryl acrylate", "HEA" is "hydroxyethyl acrylate", "n-BA" is "n-butyl acrylate", "i-BA ” indicates “isobutyl acrylate”.

<Delamination test>
In the decorative sheets of each example and each comparative example having an adhesive layer with a thickness of 10 μm, a test (delamination test) was conducted to determine whether or not the adhesive layer and the transparent resin layer were peeled off.
After the cellophane tape made by Nichiban was pressure-bonded to the surface of the decorative sheet, it was strongly peeled off with a constant force (from 1 N/inch to 20 N/inch in increments of 1 N/inch) to separate the adhesive layer and the transparent resin layer. The presence or absence of was evaluated with a microscope.
In this example, the maximum force at which peeling did not occur between the adhesive layer and the transparent resin layer was defined as "peel strength (N/inch)".

The "peel strength after moisture resistance test (N/inch)" was measured by placing the decorative sheets of each example and each comparative example in a HAST chamber (highly accelerated life test equipment) and testing them under an environment of 40°C and 90% RH. The peel strength (N/inch) obtained by conducting the above delamination test after exposure for 500 hours was defined as the peel strength (N/inch).
In addition, the "peel strength after weathering test (N/inch)" was measured with a super xenon tester (Toyo Seiki Atlas Weatherometer Ci4000) under test conditions of 180 W light irradiation, 12 minutes rain / 120 minutes cycle, 24 hours. It was set as the peel strength obtained by implementing the said delamination test.

<Evaluation Criteria>
Evaluation criteria for each example and each comparative example are as follows.
In addition, in each example, if both evaluations of peel strength (N/inch) in the "initial adhesion test" and the "moisture resistance test" were "O", the sample was considered to be acceptable. If the evaluation of the "initial adhesion test" is "O", it means that it is suitable for use in not particularly harsh environments such as fittings and floors, for example. Also, if the evaluation of the "moisture resistance test" is "O", it means that it is suitable for use around water, such as near window sashes, kitchens, bathrooms, etc., as an example.
Further, in Table 1, the comparative examples for which the "initial adhesion test" was not "O" were not subjected to the "humidity resistance test" and "weather resistance test", and were indicated as "-".

[Initial adhesion test]
○: Peel strength is 15 N / inch or more △: Peel strength is 10 N / inch or more and less than 15 N / inch ×: Peel strength is less than 10 N / inch

[Moisture resistance test]
○: Peel strength decreased from 0% to 20% from initial adhesion △: Peel strength decreased from 20% to 40% from initial adhesion ×: Peel strength decreased from initial adhesion by 40% or more

As shown in Table 1, the decorative sheets of Examples 1 to 8 were shown to be decorative sheets in which the occurrence of delamination between the adhesive layer and the transparent resin layer was reduced. In particular, it was shown that the decorative sheets of Examples 5 and 6 are also excellent in weather resistance.

INDUSTRIAL APPLICABILITY The present invention can be used as a decorative sheet that requires durability against high temperature and high humidity such as building exteriors and bathrooms, and can also be used as an indoor sheet such as a surface material for fittings and a floor material.

10 decorative sheet 11 base material (polyolefin base material)
12 Pattern layer 13 Adhesive layer (anchor coat layer)
14 transparent resin layer 15 surface protective layer (top coat layer)
16 Primer layer

Claims (5)

A decorative sheet comprising, in this order, a polyolefin base material, a pattern layer, an anchor coat layer, a transparent resin layer containing polypropylene as a main component, and a top coat layer,
The anchor coat layer is composed of an acrylic resin and an isocyanate curing agent as a cross-linking component,
The acrylic resin comprises (a) at least one monofunctional acrylate monomer having 4 or less carbon atoms and a homopolymer glass transition temperature of 0° C. or less, and (b) monofunctional acrylic acid having 8 or more carbon atoms. At least one ester monomer and (c) at least one monofunctional acrylic acid ester monomer having a hydroxyl group are used, and (a) accounts for more than half of the total mass of the monomers, and the glass transition temperature is − A decorative sheet characterized by being a resin having a temperature within the range of 45°C to -10°C and a hydroxyl value within the range of 40 mgKOH/g or more and 200 mgKOH/g or less. 2. The decorative sheet according to claim 1, wherein the topcoat layer contains, as a weather resistant agent, at least one of an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR-type skeleton. The thickness of the polyolefin base material is in the range of 50 μm or more and 100 μm or less,
The film thickness of the pattern layer is in the range of 1 μm or more and 5 μm or less,
The film thickness of the anchor coat layer is in the range of 1 μm or more and 3 μm or less,
The film thickness of the transparent resin layer is in the range of 70 μm or more and 100 μm or less,
3. The decorative sheet according to claim 1, wherein the film thickness of the topcoat layer is in the range of 3 [mu]m to 15 [mu]m. 4. The decorative sheet according to any one of claims 1 to 3, wherein the top coat layer is made of a resin containing urethane polymer as a main component. further comprising a primer layer formed on the back surface of the polyolefin base material, which is the surface opposite to the pattern layer side surface;
The pattern layer is formed of colored ink containing a binder resin,
5. The primer layer according to any one of claims 1 to 4, wherein the primer layer is formed of the same component as the binder resin contained in the colored ink for forming the pattern layer. cosmetic sheet.

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