JP7234593B2 - makeup sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a decorative sheet having excellent durability against at least high temperature and high humidity.

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.
Although the decorative sheet is a laminate, especially in building exteriors, bathrooms, etc., moisture enters the interior of the decorative sheet from the edges, causing the problem of delamination.
Generally, when laminating a laminate, an adhesive layer may be provided, and an acrylic resin, a polyurethane resin, an epoxy resin, or a polyester resin is generally used for the adhesive layer in many cases (for example, Patent Document 1).

For applications that require resistance to moisture and heat, acrylic resins without hydrolyzable functional groups can be used. There were problems such as water intrusion.

Japanese Patent No. 4737722

SUMMARY OF THE INVENTION An object of the present invention is to provide a decorative sheet excellent in workability as well as durability against high temperature and high humidity (resistance to moist heat).

In order to achieve the above object, a decorative sheet according to one aspect of the present invention comprises a base material layer, a pattern layer, an adhesive layer, and a transparent resin layer laminated in this order, and the adhesive layer comprises a poly It contains a urethane resin composed of caprolactone polyol, polyalkylene glycol , polyisocyanate and neopentyl glycol as constituent elements , wherein X is the amount of polycaprolactone polyol, Y is the amount of polyalkylene glycol, and Y is the amount of polyisocyanate. is Z, and the amount of neopentyl glycol is N, the following formulas 1 to 3 are obtained.
3<(X+Y+Z)/N<50 (Formula 1)
0.1<X/Y<10 (Formula 2)
Z/(X+Y+Z+N)<0.5 (Formula 3)

ADVANTAGE OF THE INVENTION According to this invention, the decorative sheet excellent in heat-and-moisture resistance and processability can be provided.

1 is a schematic cross-sectional view showing a decorative sheet according to the present invention; FIG. FIG. 2 is a diagram showing the composition of urethane resin contained in the adhesive layer of the decorative sheet according to the present invention;

Next, embodiments according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between thickness and planar dimension, the ratio of thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. In addition, it is a matter of course that there are portions with different dimensional relationships and ratios between the drawings.
Further, the embodiments shown below are examples of devices and methods for embodying the technical idea of the present invention. etc. are not specified below. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

[Configuration of decorative sheet]
As shown in FIG. 1, a decorative sheet 10 according to an embodiment (hereinafter referred to as the present embodiment) of the present invention includes a base layer 11, a pattern layer 12, an adhesive layer 13, a transparent resin layer 14, and a surface protective layer. layer 15 and so on are laminated in this order.

[Base material layer]
Polyolefin or polyester is preferably used for the base material layer 11, and can be arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
The substrate layer 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 supplement adhesion with adjacent layers.

[Pattern layer]
The pattern layer 12 is a pattern printed on the base material layer 11 using ink. The ink used to form the pattern layer 12 may contain a binder, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc. alone or each modified product. can be appropriately selected from among and used. 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.
As a method of curing the ink used for forming the pattern layer 12, there is a method of curing the ink by irradiation with ultraviolet rays, electron beams, or the like. Among them, the most common method is to use urethane-based ink and cure it with polyisocyanate.

In addition to these binders, the ink used to form the pattern layer 12 contains, for example, coloring agents such as pigments and dyes contained in ordinary inks, various additives such as extenders, solvents, and light stabilizers. It is 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.
A method for forming 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.

[Adhesion layer]
The adhesive layer 13 contains a urethane resin composed of polycaprolactone polyol, polyalkylene glycol, and polyisocyanate, and is formed using an ordinary coating method such as gravure coating, microgravure coating, comma coating, knife coating, and die coating. be done.
The urethane resin contained in the adhesive layer 13 can be synthesized by a known technique (addition polymerization reaction of polyol and polyisocyanate). That is, the adhesive layer can be cured by adding an appropriate amount of a curing agent such as isocyanate to the terminal of the urethane resin having a hydroxyl group.

The polycaprolactone polyol that constitutes the urethane resin of the present embodiment is a polyol obtained by ring-opening polymerization of ε-caprolactone, and has an ester bond in its structure, so it can be expected to have good adhesion to a substrate. It has excellent hydrolysis resistance compared to general polyesters such as dehydration polymers of adipic acid and 1,6-hexanediol.
Polyalkylene glycol, which is a component of urethane resin, has a polyether structure and is inferior in hydrolysis resistance to polycaprolactone polyol, but is superior in flexibility. In this embodiment, by using the same material together with polycaprolactone polyol, both adhesion to the substrate layer 11 and processability are achieved.
As polyalkylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or the like can be used, and polytetramethylene glycol having high hydrophobicity is preferable from the viewpoint of resistance to heat and humidity.

Further, it is preferable that neopentyl glycol is further included as a component of the urethane resin. Moisture resistance is improved by including this neopentyl glycol in the urethane resin.
The polycaprolactone polyol and polyalkylene glycol used as constituents of the urethane resin can be appropriately selected from various commercially available materials from the viewpoint of molecular weight and the like.
As the polyisocyanate used as a component of the urethane resin, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated products thereof, and the like can be used, but isophorone diisocyanate is preferable from the viewpoint of heat and humidity resistance.

Although the composition of the urethane resin of this embodiment is not particularly limited, considering the suitability of the adhesive layer 13 formed by coating and various performances of the decorative sheet 10, as shown in FIG. When the amount of each unit (caprolactone unit (CP unit), alkylene glycol unit (AG unit), isocyanate unit (I unit), neopentyl glycol unit (NG unit) is X, Y, Z, N) , the following relational expressions (formulas 1 to 3) are desirable.
3<(X+Y+Z)/N<50 (Formula 1)
0.1<X/Y<10 (Formula 2)
Z/(X+Y+Z+N)<0.5 (Formula 3)

The molecular weight of the urethane resin of the present embodiment is not particularly limited, but considering the printability of the adhesive layer formed by normal printing and various performances of the decorative sheet, the weight average molecular weight (Mw) is from 5,000. A range of 100,000 is preferred.
Further, the curing agent used for curing the urethane resin of the present embodiment is not particularly limited, and includes hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate and its hydrogenated products, diphenylmethane diisocyanate and its hydrogenated products. It can be used by appropriately selecting from commercially available curing agents such as
The method of joining the transparent resin layer 14 to the substrate layer 11 laminated with the pattern layer 12 may be through the adhesive layer 13, and various lamination methods such as heat lamination, extrusion lamination, dry lamination, and sand lamination may be used. can be used.

[Transparent resin layer]
Polyolefin is preferably used for the transparent resin layer 14, and examples thereof include polypropylene, polyethylene, polybutene, and various α-olefin copolymers (copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.). is used.
The transparent resin layer 14 may contain various additives such as ultraviolet absorbers, heat stabilizers, light stabilizers, anti-blocking agents, catalyst scavengers, colorants, light scattering agents, and luster modifiers, if necessary. good.
A method for forming the transparent resin layer 14 is not particularly limited, and 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 irregularities in order to impart a design property. Examples of the method for 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.

[Surface protective layer]
The surface protective layer 15 is a layer provided to the decorative sheet 10 to impart 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.
The surface protective layer 15 may optionally contain various additives such as ultraviolet absorbers, heat stabilizers, light stabilizers, anti-blocking agents, catalyst scavengers, colorants, light scattering agents, and luster modifiers. You may
The method for forming the surface protective layer 15 is not particularly limited. The surface protective layer 15 may be formed by curing by a method suitable for the material, such as thermal curing, ultraviolet curing, or the like.
The surface protective layer 15 may be provided after bonding the pattern layer 12 provided on the base material layer 11 to the transparent resin layer 14 via the adhesive layer 13 .

Next, the thickness of each layer constituting the decorative sheet 10 of this embodiment will be described.
The base material layer 11 is 20 μm to 150 μm in consideration of printing workability, cost, etc., the pattern layer 12 is 0.5 to 10 μm, the adhesive layer 13 is 1 μm to 20 μm, the transparent resin layer 14 is 20 μm to 200 μm, The thickness of the surface protective layer 15 is preferably 3 μm to 20 μm. Also, the total thickness of the decorative sheet 10 is preferably within the range of 45 μm to 250 μm.

[Effect of decorative sheet]
Next, the effect of the decorative sheet 10 of this embodiment will be described.
The adhesive layer 13 of the decorative sheet 10 is made of a urethane resin composed of polycaprolactone polyol, which has excellent hydrolysis resistance, polyalkylene glycol, which achieves both adhesion and workability with the base layer 11, and polyisocyanate. Since it is contained, cracking and whitening of the adhesive layer 13 are less likely to occur, and the workability of the decorative sheet 10 can be improved.
In addition, by containing neopentyl glycol as a component of the urethane resin of the adhesive layer 13, the moist heat resistance of the decorative sheet 10 can be improved.

In addition, by using polytetramethylene glycol instead of polyalkylene glycol, which is a component of the urethane resin of the adhesive layer 13, the resistance to moisture and heat of the decorative sheet 10 can be further improved.
In addition, by using isophorone diisocyanate as the polyisocyanate that is a component of the urethane resin of the adhesive layer 13, the decorative sheet 10 that is even more excellent in resistance to moisture and heat can be obtained.
Furthermore, since the transparent resin layer 14 is made of polyolefin resin, no dioxin is generated even if the decorative sheet 10 is burned at the time of disposal, and the environmental load can be suppressed.
Furthermore, by laminating the surface protective layer 15 on the transparent resin layer 14, the decorative sheet 10 can be provided with functions of weather resistance, scratch resistance, stain resistance, and design.

Next, the present invention will be described more specifically by showing decorative sheets of Examples and Comparative Examples.
<Example 1>
Using (polycaprolactone polyol, polytetramethylene glycol, neopentyl glycol) as a polyol and isophorone diisocyanate as a polyisocyanate, a hydroxyl group-terminated urethane resin having a number average molecular weight of 1.0×10 ⁵ is synthesized by a known addition polymerization method. bottom. An appropriate amount of a curing agent (a nurate form of hexamethylene diisocyanate) was added to the urethane resin to prepare an adhesive.

A pattern layer 12 (thickness 3 μm) is provided by gravure-printing a wood grain pattern on a polyethylene raw fabric (thickness 70 μm) with concealability using two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.). A transparent polyolefin resin was dry-laminated on the obtained base material layer 11 via the above-mentioned adhesive (Takelac A540; manufactured by Mitsui Chemicals, Inc.) (thickness: 2 μm). Furthermore, as the surface protective layer 15, 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 coated on the protective film (layer thickness of 8 μm) to obtain the decorative sheet 10 of Example 1.

<Example 2>
A decorative sheet 10 of Example 2 was obtained in the same manner as in Example 1, except that neopentyl glycol was not used as the polyol component.
<Example 3>
A decorative sheet 10 of Example 3 was obtained in the same manner as in Example 1, except that polytetramethylene glycol in Example 1 was replaced with polypropylene glycol as the polyol component.

<Example 4>
A decorative sheet 10 of Example 4 was obtained in the same manner as in Example 1, except that isophorone diisocyanate in Example 1 was replaced with xylylene diisocyanate as the polyisocyanate component.
<Example 5>
A decorative sheet of Example 5 was prepared in the same manner as in Example 1, except that neopentyl glycol was not used as the polyol component and that isophorone diisocyanate was replaced with xylylene diisocyanate as the polyisocyanate component. Got 10.

<Example 6>
A decorative sheet 10 of Example 6 was obtained in the same manner as in Example 1, except that polytetramethylene glycol in Example 1 was replaced with polypropylene glycol as the polyol component and neopentyl glycol was not used. rice field.
<Example 7>
Example 1 except that polytetramethylene glycol was replaced with polypropylene glycol as the polyol component, that neopentyl glycol was not used, and that isophorone diisocyanate was replaced with xylylene diisocyanate as the polyisocyanate component. A decorative sheet 10 of Example 7 was obtained in the same manner as above.

<Comparative Example 1>
A decorative sheet 10 of Comparative Example 1 was obtained in the same manner as in Example 1, except that polycaprolactone polyol was not used as the polyol component.
<Comparative Example 2>
A decorative sheet 10 of Comparative Example 2 was obtained in the same manner as in Example 1, except that polyalkylene glycol was not used as the polyol component.

<Evaluation judgment>
The decorative sheets 10 of Examples 1 to 7 and Comparative Examples 1 and 2 described above were evaluated for workability and resistance to moist heat by the following methods. Table 1 shows the evaluation results.
(a) Workability A sample obtained by attaching a decorative sheet to an aluminum plate (thickness 0.4 mm) using an adhesive for building materials (No Tape Industry, No. 5211) was bent at an ambient temperature of 5 ° C. at 90 °. The appearance was visually observed.
Evaluation criteria ○: No cracks observed in the pattern layer ×: Cracks observed in the pattern layer

(b) Wet heat resistance The decorative sheet 10 was subjected to a wet heat treatment in a HAST chamber (105°C 100% RH, 192 hours), and then the T-peel strength between the transparent resin layer 14 and the base layer 11 was measured (sample width: 25 mm, pulling speed: 5 mm/sec).
Evaluation criteria ◎: Base material fractured without forming a peel interface ○○: Debonded surface formed while base material deformation occurred ○: Debonded surface formed without base material deformation ×: Delamination occurred during sample handling and measurement was not possible

As can be seen from Table 1, the decorative sheets 10 shown in Examples 1 to 7 are excellent in workability and resistance to moist heat by using a urethane resin containing a specific component as the resin of the adhesive layer 13. . In particular, embodiments 2, 4, and 5 in which polytetramethylene glycol is used as polyalkylene glycol are superior in heat resistance to embodiments 3, 6, and 7, and neopentyl glycol and isophorone diisocyanate are used as polyisocyanate. Example 1 shows particularly excellent results in terms of wet heat resistance.

DESCRIPTION OF SYMBOLS 10 Decorative sheet 11 Base material layer 12 Pattern layer 13 Adhesive layer 14 Transparent resin layer 15 Surface protection layer

Claims (5)

A substrate layer, a pattern layer, an adhesive layer, and a transparent resin layer are laminated in this order,
The adhesive layer contains a urethane resin composed of polycaprolactone polyol, polyalkylene glycol , polyisocyanate and neopentyl glycol ,
When X is the substance amount of the polycaprolactone polyol, Y is the substance amount of the polyalkylene glycol, Z is the substance amount of the polyisocyanate, and N is the substance amount of the neopentyl glycol, the following formulas 1 to 3 A decorative sheet characterized by having a relational expression of
3<(X+Y+Z)/N<50 (Formula 1)
0.1<X/Y<10 (Formula 2)
Z/(X+Y+Z+N)<0.5 (Formula 3) 2. The decorative sheet according to claim 1 , wherein said polyalkylene glycol is polytetramethylene glycol. 3. The decorative sheet according to claim 1, wherein said polyisocyanate is isophorone diisocyanate. 4. The decorative sheet according to any one of claims 1 to 3, wherein the transparent resin layer is made of polyolefin resin. 5. The decorative sheet according to any one of claims 1 to 4, wherein a surface protective layer is laminated on the transparent resin layer.

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