JP2020082520A - Decorative sheet - Google Patents

Abstract

To provide a decorative sheet excellent in both base material adhesion and moist heat resistance.SOLUTION: A decorative sheet 10 has a base material 11 and a pattern layer 12 provided on one surface of the base material 11, in which the pattern layer 12 contains an urethane resin containing polycaprolactone polyol, polyalkylene glycol and polyisocyanate as components as a binder resin.SELECTED DRAWING: Figure 1

Description

The present invention relates to a decorative sheet.

The decorative sheet may be required to have resistance to high temperature and high humidity (moisture and heat resistance) in applications such as building exterior and bathroom. The design layer that gives the decorative sheet a design is generally formed by printing an ink containing a binder resin and a pigment on a base material such as polyolefin or polyester. Conventionally, as the binder resin for the pattern layer, nitrified cotton, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc. have been used (Patent Document 1).
However, it may be difficult for these binder resins to have both good adhesion to the base material and resistance to moist heat. For example, polyester and polyester-based polyurethane show good adhesion to the above-mentioned substrate, but hydrolysis is likely to occur, and the moist-heat resistance may be insufficient. In addition, the embrittlement of the binder resin due to hydrolysis may cause the pattern layer to fall off or the transparent resin layer provided on the pattern layer to peel off.

Japanese Patent No. 4737722

An object of the present invention is to provide a decorative sheet which is excellent in wet adhesion and heat resistance as well as adhesion to a substrate.

As a result of intensive studies, the present inventors have found that the urethane resin containing specific constituent elements can be used as the binder resin of the pattern layer to achieve the above-mentioned target, and have completed the present invention.
In order to solve the above problems, a decorative sheet according to one aspect of the present invention includes a substrate, and a pattern layer provided on one surface of the substrate, the pattern layer being a polycaprolactone polyol, It is a gist to contain a urethane resin containing polyalkylene glycol and polyisocyanate as constituent elements as a binder resin.

According to one aspect of the present invention, there is provided a decorative sheet having excellent adhesion to a base material and excellent heat and moisture resistance.

It is a schematic diagram which shows the cross section of the decorative sheet which concerns on embodiment of this invention.

An embodiment of the present invention will be described with reference to the drawings.
Here, the configuration shown in FIG. 1 is schematic, and the relationship between the thickness and the plane dimension, the thickness ratio of each layer, and the like are different from the actual ones. Further, the embodiments described below exemplify a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure, etc. of the components are as follows. It is not limited to one. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims described in 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 base material 11, a pattern layer 12 formed on the base material 11, an adhesive layer 13 formed on the pattern layer 12, and a transparent resin layer 14 formed on the adhesive layer 13. And a surface protective 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 on which a pattern layer 12 is printed by an adhesive layer 13 and a surface protective layer 15 is further provided will be described with reference to FIG. To do.

(Base material)
Polyolefin or polyester is preferably used as the resin constituting the base material 11, that is, a resin component, and for example, it is arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. It is possible.
The base material 11 may be subjected to surface treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet ray treatment, and dichromic acid treatment in order to supplement the adhesion with the adjacent layer.
If the base material 11 is a polyolefin or a polyester, the adhesiveness with the pattern layer 12 described later is ensured.

(Pattern layer)
The pattern layer 12 is formed by printing a pattern ink using a urethane resin containing at least specific components, that is, polycaprolactone polyol, polyalkylene glycol and polyisocyanate, as a binder resin on the substrate 11.
The urethane resin of this embodiment can be synthesized by a known technique, that is, an addition polymerization reaction of a polyol and a polyisocyanate. The terminal of the urethane resin is usually a hydroxyl group or an isocyanate group sealed with an amine. When the terminal of the urethane resin has hydroxyl groups, the pattern layer 12 can be cured by mixing a curing agent such as isocyanate with the pattern ink.

The polycaprolactone polyol constituting the urethane resin of the present embodiment is a material obtained by ring-opening polymerization of ε-caprolactone and has an ester bond inside. Therefore, the adhesion to the base material 11, that is, the adhesion to the base material is improved. The above polycaprolactone polyol is generally superior in hydrolysis resistance as compared with a general-purpose polyester polyol obtained by polycondensation of a dicarboxylic acid such as adipic acid and a diol.

The polyalkylene glycol that constitutes the urethane resin of the present embodiment has a polyether structure and is superior in hydrolysis resistance as compared with the above-mentioned polycaprolactone polyol, but tends to be inferior in heat resistance and substrate adhesion. is there. In the present embodiment, by using polyalkylene glycol in combination with polycaprolactone polyol, both substrate adhesion and wet heat resistance are achieved.
As the polyalkylene glycol, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or the like can be used, and polytetramethylene glycol having high hydrophobicity is preferable from the viewpoint of heat and humidity resistance.

The polyurethane resin of the present embodiment preferably further contains neopentyl glycol as a constituent element. Moisture and heat resistance is improved by containing neopentyl glycol.
The polycaprolactone polyol and polyalkylene glycol of the present embodiment can be appropriately selected and used from various commercially available materials from the viewpoints of molecular weight and functional number (number of hydroxyl groups per molecule). As the polyisocyanate, for example, diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and xylylene diisocyanate, and hydrogenated products thereof can be used, and isophorone diisocyanate is preferable from the viewpoint of resistance to moist heat.

The composition of the urethane resin of the present embodiment is not particularly limited, but in consideration of printability of the picture layer 12 formed by normal printing and various performances of the decorative sheet 10, the urethane resin represented by the following structural formula is used. When the amounts of substances of each site (caprolactone unit (CL), alkylene glycol unit (AG), diisocyanate unit (I), neopentyl glycol (NPG)) are respectively X, Y, Z, N, the following relation It is preferable to satisfy the formulas (1) to (3).

3<(X+Y+N)/Z<50 (Formula 1)
0.1<X/Y<10 (Formula 2)
N/(X+Y+X+N)<0.2 (Formula 3)
Within the above numerical range, printability can be easily improved.

The molecular weight of the urethane resin of the present embodiment is not particularly limited, and, for example, considering the printability of the pattern layer 12 formed by normal printing and various performances of the decorative sheet 10, the mass average molecular weight (MW) is It is preferably in the range of 5,000 or more and 100,000 or less.
Within the above numerical range, printability can be easily improved.
The curing agent used for curing the urethane resin of the present embodiment is not particularly limited, for example, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate and hydrogenated product thereof, or diphenylmethane diisocyanate and its water. It can be appropriately selected and used from commercially available curing agents including additives.

The pattern layer 12 is usually formed by printing a pattern ink using the urethane resin of the present embodiment as a binder resin on the substrate 11, but other resin components may be added if necessary.
As the components other than the binder resin of the pattern ink, for example, various additives such as colorants such as pigments and dyes, extender pigments, solvents and light stabilizers can be used. Examples of the pigment include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, pearl pigments such as mica, and the like.
The method of providing the pattern layer 12 is not particularly limited, and for example, a usual printing method such as gravure printing, offset printing, screen printing, flexo printing, ink jet printing can be used.

(Adhesive layer)
The method of joining the transparent resin layer 14 to the base material 11 on which the pattern layer 12 is formed by printing is not particularly limited. For example, thermal lamination, extrusion lamination, dry lamination, sand sandwiching the adhesive layer 13 as necessary. Various laminating techniques such as laminating can be used.
The material of the adhesive layer 13 is not particularly limited, and can be appropriately selected and used from resin materials such as urethane-based, acrylic-based, acrylic silicon-based, fluorine-based, and epoxy-based resin materials. The adhesive layer 13 is formed by using a material that is appropriately selected and made into an ink, using a normal coating method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating.

(Transparent resin layer)
The material of the transparent resin layer 14 is not particularly limited, and for example, polyolefin is preferably used. As the polyolefin, for example, polypropylene, polyethylene, polybutene, and various α-olefin copolymers (copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.) are used.
The transparent resin layer 14 is mixed with various additives such as an ultraviolet absorber, a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent, and a luster modifier, if necessary. You may.

The method for producing the transparent resin layer 14 is not particularly limited, and for example, a usual method such as calender film formation or extrusion film formation can be used.
The transparent resin layer 14 may be provided with surface irregularities, so-called embossing, in order to impart a design property. Examples of the method of providing the unevenness include a method of subjecting the transparent resin layer 14 to extrusion molding and then performing hot embossing, and a method of performing embossing simultaneously with extrusion molding using a cooling roll provided with unevenness at the time of extrusion formation.

(Surface protection layer)
The surface protective layer 15 is a layer provided for imparting functions such as weather resistance, scratch resistance, stain resistance, and design property to the decorative sheet 10. The material of the surface protective layer 15 is not particularly limited and may be appropriately selected from urethane-based, acrylic-based, acryl-silicone-based, fluorine-based, epoxy-based resin materials and the like.
The surface protective layer 15 is compounded with various additives such as an ultraviolet absorber, a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent and a luster modifier, if necessary. You may.
The method for forming the surface protective layer 15 is not particularly limited, and after applying the above-mentioned material in a liquid form by a usual method such as gravure coating, micro gravure coating, comma coating, knife coating, or die coating. Then, the surface protection layer 15 is formed by curing by a method suitable for the material such as heat curing or ultraviolet curing.

In the decorative sheet 10 of this embodiment, the layer thickness of the base material 11 is preferably in the range of 20 μm or more and 150 μm or less in consideration of printing workability, cost, and the like. Further, the layer thickness of the pattern layer 12 is preferably in the range of 0.5 μm or more and 10 μm or less. The layer thickness of the adhesive layer 13 is preferably in the range of 1 μm or more and 20 μm or less. The layer thickness of the transparent resin layer 14 is preferably in the range of 20 μm or more and 200 μm or less. The layer thickness of the surface protective layer 15 is preferably within the range of 3 μm or more and 20 μm or less. The total thickness of the decorative sheet 10 is preferably in the range of 45 μm or more and 250 μm or less.
Within the above numerical range, the printing workability can be easily improved and the manufacturing cost can be reduced.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.
<Example 1>
Polycaprolactone diol, polytetramethylene glycol and neopentyl glycol are used as the polyol, isophorone diisocyanate is used as the polyisocyanate, and a hydroxyl group-terminated urethane resin having a number average molecular weight of 2×10 ⁴ is synthesized by a known addition polymerization method. did. A copper phthalocyanine pigment was dispersed in the urethane resin at a mass ratio of pigment/urethane resin=20/80 to prepare a pattern ink.
An isocyanate curing agent was added to the ink, and a pattern layer (thickness 3 μm) was provided by gravure printing on a polyethylene original fabric (thickness 70 μm) having a hiding property. Subsequently, a transparent homopolypropylene resin was extruded and laminated on the pattern layer via an adhesive for dry lamination (thickness 2 μm) to form a transparent resin layer (thickness 80 μm), and the decorative sheet of Example 1 was obtained. ..

<Example 2>
A decorative sheet of Example 2 was obtained in the same manner as in Example 1, except that the polyethylene raw material was replaced with polybutylene terephthalate raw material (thickness 70 μm).
<Example 3>
A decorative sheet of Example 3 was obtained in the same manner as in Example 1 except that neopentyl glycol was not used as the polyol component in the urethane resin synthesis of Example 1.
<Example 4>
A decorative sheet of Example 4 was obtained in the same manner as in Example 3 except that polytetramethylene glycol was replaced with polypropylene glycol as the polyol component in the urethane resin synthesis of Example 3.

<Example 5>
A decorative sheet of Example 5 was obtained in the same manner as in Example 1 except that xylenediisocyanate was used instead of isophorone diisocyanate as the isocyanate component in the synthesis of the urethane resin of Example 1.
<Example 6>
Example 6 was repeated in the same manner as in Example 1 except that neopentyl glycol was not used as the polyol component in the urethane resin synthesis of Example 1 and that isophorone diisocyanate was replaced with xylylene diisocyanate as the isocyanate component. I got a makeup sheet.

<Example 7>
A decorative sheet of Example 7 was obtained in the same manner as in Example 6 except that in the synthesis of the urethane resin of Example 6, polytetramethylene glycol was replaced with polypropylene glycol as the polyol component.
<Example 8>
A decorative sheet of Example 8 was obtained in the same manner as in Example 3 except that the polyethylene raw material was replaced with polybutylene terephthalate raw material (thickness 70 μm).
<Example 9>
A decorative sheet of Example 9 was obtained in the same manner as in Example 6, except that the polyethylene raw material was replaced with polybutylene terephthalate raw material (thickness 70 μm).

<Comparative Example 1>
A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that polytetramethylene glycol was not used as the polyol component in the urethane resin synthesis of Example 1.
<Comparative example 2>
A decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that polycaprolactone diol was not used as the polyol component in the urethane resin synthesis of Example 1.

<Reference example>
The urethane resin of Example 1 was replaced with a polyester urethane resin (addition polymer of a polyester diol obtained by dehydration condensation of adipic acid and propylene glycol and isophorone diisocyanate, having a number average molecular weight of 2×10 ⁴ ). A decorative sheet of Reference Example was obtained in the same manner as in Example 1 except for the above points.

<Evaluation>
With respect to the decorative sheets obtained in the above Examples, Comparative Examples, and Reference Examples, the adhesion and moist heat resistance were evaluated by the following methods. The evaluation results are shown in Table 1.

(A) Adhesion to Substrate The T-shaped peel strength between the transparent resin layer and the substrate was measured for a sample that was stored in a room temperature environment for 24 hours after preparation of the decorative sheet (sample width: 25 mm, pulling speed: 5 mm/sec. ).
<Evaluation criteria>
⊚: The base material broke without forming a peeling interface ◯: A peeled surface was generated while the base material was deformed Δ: A peeled surface was generated without the base material deformed ×: Peeling occurred during sample handling, and measurement was not possible If the evaluation was "○" or more, it was determined to pass.

(B) Moisture and heat resistance A sample that has been stored in a room temperature environment for 24 hours after making a decorative sheet is subjected to a pressure cooker test (105°C, 100% RH, 192 hours) using a HAST chamber, and then a T between the transparent resin layer and the substrate is obtained. The character peel strength was measured (sample width: 25 mm, pulling speed: 5 mm/sec).
<Evaluation criteria>
⊚: The base material broke without forming a peeling interface ◯: A peeled surface was generated while the base material was deformed Δ: A peeled surface was generated without the base material deformed ×: Peeling occurred during sample handling, and measurement was not possible If the evaluation was “Δ” or more, it was determined to pass.

The decorative sheet shown in this example uses a urethane resin containing specific constituents, that is, polycaprolactone polyol, polyalkylene glycol and polyisocyanate, as the binder resin of the pattern layer 12, and the urethane resin is used. As a result, it was revealed that the base material adhesion and the wet heat resistance were both excellent.

INDUSTRIAL APPLICABILITY The present invention can be used as a decorative sheet which is required to have durability against high temperature and high humidity such as building exteriors and bathrooms.

10 Decorative Sheet 11 Base Material 12 Picture Layer 13 Adhesive Layer 14 Transparent Resin Layer 15 Surface Protection Layer

Claims (8)

A base material, and a pattern layer provided on one surface of the base material,
The decorative layer is characterized in that the pattern layer contains a urethane resin containing polycaprolactone polyol, polyalkylene glycol and polyisocyanate as constituent elements as a binder resin. The decorative sheet according to claim 1, further comprising neopentyl glycol as a constituent element of the urethane resin. The said polyalkylene glycol is polytetramethylene glycol, The decorative sheet of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The decorative sheet according to claim 1, wherein the polyisocyanate is isophorone diisocyanate. The base material contains a resin component,
The decorative sheet according to any one of claims 1 to 4, wherein the resin component of the base material is polyolefin. The base material contains a resin component,
The decorative sheet according to any one of claims 1 to 4, wherein the resin component of the base material is polyester. The decorative sheet according to any one of claims 1 to 6, wherein a transparent resin layer is laminated on the pattern layer. The decorative sheet according to claim 7, wherein a surface protective layer is laminated on the transparent resin layer.

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