Decorative sheets and decorative panels

Abstract

The present invention provides a decorative laminate with high adhesion between the thermoplastic resin layer and the base paper layer and excellent machinability, a decorative sheet used in the decorative laminate, and a method for manufacturing the same. [Solution] A decorative sheet comprising, in this order, a base paper layer, a thermoplastic resin layer provided on one surface of the base paper layer, a pattern layer, and a surface protection layer, wherein the base paper layer contains cellulose nanofibers. Or, the decorative sheet according to claim 1, wherein the thermoplastic resin layer contains cellulose nanofibers. Or, the decorative sheet according to claim 1 or 2, wherein the thermoplastic resin layer contains 0.1 parts by mass or more of cellulose nanofibers.

Description

[Technical Field]

[0001] The present invention relates to decorative sheets and decorative panels. [Background technology]

[0002] Traditionally, decorative sheets have been used as surface materials for furniture and building materials for houses. Decorative sheets are formed by laminating a patterned layer, which provides design appeal through patterns, onto one side of a base paper.

[0003] One example of a decorative sheet comprising a base paper and a pattern layer is the decorative paper (decorative sheet) described in Patent Document 1. The decorative sheet described in Patent Document 1 is a decorative sheet in which a thermoplastic resin layer, a base color layer, and a pattern layer are laminated in this order on one side of the base paper, and because it includes a thermoplastic resin layer with moisture resistance between the base paper and the pattern layer, it can provide a decorative sheet with excellent water resistance and oil resistance. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-75442 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the decorative sheet described in Patent Document 1 has poor adhesion strength between the thermoplastic resin layer and the base paper layer, which may cause delamination when cut. The above-mentioned risks are problems that can be seen in decorative sheets formed from a thermoplastic resin layer and a base paper layer.

[0006] Based on the above circumstances, the object of the present invention is to provide a decorative laminate with high adhesion between the thermoplastic resin layer and the base paper layer and excellent machinability, a decorative sheet used in the decorative laminate, and a method for manufacturing the same. [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention includes the following:

[0008] [1] A decorative sheet comprising, in this order, a base paper layer, a thermoplastic resin layer provided on one surface of the base paper layer, a pattern layer, and a surface protection layer, wherein the base paper layer contains cellulose nanofibers.

[0009] [2] The decorative sheet according to [1], wherein the thermoplastic resin layer contains cellulose nanofibers.

[0010] [3] A decorative sheet according to [1] or [2], wherein the cellulose nanofiber is contained in the thermoplastic resin layer in an amount of 0.1 parts by mass or more.

[0011] [4] A decorative sheet according to [1] or [2], wherein the T-type peel strength of the base paper layer measured under the following measurement conditions is 130 gf / 15 mm or more. (Measurement conditions) Test name: JIS K 6854-3, T-type peel test Temperature: 23℃±2℃ Humidity: 50%RH±10%RH Specimen shape: 15mm wide

[0012] [5] The decorative sheet according to [1] or [2], wherein the thermoplastic resin layer contains polypropylene or polyethylene.

[0013] [6] A decorative sheet according to [1] or [2], comprising a matte layer formed on the upper side of the patterned layer, and a surface protective layer formed on the upper side of the matte layer and in a position synchronized with the pattern of the patterned layer, having a gloss different from that of the matte layer.

[0014] A decorative member (decorative panel) manufactured using a decorative sheet relating to [7][1] or [2] and a base material for decorative members provided below the decorative sheet. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a decorative board having high adhesion between a thermoplastic resin layer and a base paper layer and excellent cutting properties, and a decorative sheet used for the decorative board.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a decorative sheet and a decorative board according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0017] An embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of a decorative sheet 10 and a decorative board 100 according to the present embodiment. The decorative board 100 includes a base material 8 for a decorative board and a decorative sheet 10.

[0018] In the present embodiment, as shown in FIG. 1, the thickness direction of the decorative sheet 10 and the decorative board 100 is defined as the "vertical direction V", the side of the decorative board 100 where the base material 8 for the decorative board is provided is defined as the "lower side LO" in the vertical direction V, and the side of the decorative board 100 where the decorative sheet 10 is provided is defined as the "upper side UP" in the vertical direction V.

[0019] (Substrate for Decorative Board) As the base material 8 for the decorative board, for example, medium density fiberboard (MDF) or particle board can be adopted. As the base material 8 for the decorative board, a metal-based plate-like member such as aluminum or stainless steel, or a composite board in which a metal such as aluminum is attached to both sides of a core material made of a resin such as polyethylene may be adopted.

[0020] (Decorative Sheet) The decorative sheet 10 includes a base paper layer 1, a thermoplastic resin layer 2, an undercoat coloring layer 3, a pattern layer 4, a matte layer 5, and a surface protection layer 6. One or more of the undercoat coloring layer 3 and the matte layer 5 may be omitted.

[0021] (Base Paper Layer) As the base paper layer 1, a fibrous sheet such as tissue paper or titanium paper can be adopted. Also, the basis weight of the base paper layer 1 is 20 g / m2 More than 100g / m 2 The following is preferable: 20 g / m 2 More than 60g / m 2 The following is more preferable. This allows the base paper layer 1 to have elasticity and toughness, making the decorative sheet 10 less prone to wrinkles and preventing curling of the decorative sheet 10.

[0022] The base paper layer 1 contains cellulose nanofibers. Cellulose nanofibers are obtained by mechanically defibrating plant materials and refer to those with a width of 3 to 100 nm, an aspect ratio of 10 or more, and a length of up to 100 μm. Since the paper fibers (pulp) that make up the base paper layer 1 and the cellulose nanofibers have different fiber diameters, they can be clearly distinguished by magnified observation, and it can be determined that the base paper layer 1 contains cellulose nanofibers.

[0023] The base paper layer 1 preferably contains 0.1 parts by mass or more of cellulose nanofibers per 100 parts by mass of the paper constituting the base paper layer 1. While there is no upper limit on the cellulose nanofiber content in the base paper layer 1, it may be 40 parts by mass or less.

[0024] The effects of the base paper layer 1 containing cellulose nanofibers will be discussed later.

[0025] The surface of the base paper layer 1 on which the thermoplastic resin layer 2 is laminated may be subjected to corona treatment or ozone treatment to generate polar groups and improve wettability. This increases the adhesion between the base paper layer 1 and the thermoplastic resin layer 2.

[0026] The material of the base paper layer 1 preferably has a T-type peel strength of 130 gf / 15 mm or higher. The T-type peel strength can be adjusted by changing the basis weight of the base paper layer 1. The T-type peel strength can be measured by the following method. (Measurement conditions) Test name: JIS K 6854-3, T-type peel test Temperature: 23℃±2℃ Humidity: 50%RH±10%RH Specimen shape: 15mm wide

[0027] (thermoplastic resin layer) The thermoplastic resin layer 2 is formed on the upper surface UP of the base paper layer 1, and the lower surface LO of the thermoplastic resin layer 2 and the upper surface UP of the base paper layer 1 are bonded to each other. Polypropylene or polyethylene is preferred as the thermoplastic resin layer 2. The upper surface UP 2s of the thermoplastic resin layer 2 may be subjected to corona treatment to improve wettability. This increases the adhesion between the thermoplastic resin layer 2 and the base colored layer 3 formed on the upper surface UP of the thermoplastic resin layer 2.

[0028] As a method for laminating the thermoplastic resin layer 2, methods such as melt extrusion molding, dry lamination, wet lamination, non-solvent lamination, or wax lamination can be employed. Through these methods, the molten thermoplastic resin, which is the material for the thermoplastic resin layer 2, penetrates between the cellulose fibers that make up the base paper layer 1. The molten resin that has penetrated the base paper layer 1 cools and solidifies to become the thermoplastic resin layer 2. At that time, the molten resin encapsulates the cellulose fibers, causing the resulting thermoplastic resin layer 2 to adhere to the base paper layer 1.

[0029] (Undercoat coloring layer) The base colored layer 3 is a layer formed by printing on the upper surface UP 2s of the thermoplastic resin layer 2. The base colored layer 3 is a two-component curing type urethane resin-based ink containing an isocyanate curing agent and a polyol, and is a layer formed with an ink containing 10% or more urethane resin as organic solids. Furthermore, gravure printing, flexographic printing, or screen printing can be used as the printing method.

[0030] Because urethane resin has polar groups, it exhibits excellent adhesion. Therefore, by forming a base colored layer 3 containing 10% or more urethane resin on the upper surface UP 2s of the corona-treated thermoplastic resin layer 2, the thermoplastic resin layer 2 and the base colored layer 3 exhibit high adhesion.

[0031] (Pattern layer) The pattern layer 4 is a layer formed by printing on the upper surface UP of the base color layer 3. The pattern layer 4 has a pattern 41. The pattern layer 4 is formed by printing a pattern such as wood grain, stone pattern, or sand pattern. Known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be used as the printing method. In addition, known printing inks suitable for the printing method adopted can be used for the pattern layer 4.

[0032] (Matte finish) The matte layer 5 is a layer formed by printing on the upper surface UP of the pattern layer 4. It is desirable that the matte layer 5 be made of a material that is transparent or semi-transparent enough to allow the pattern 41 of the pattern layer 4 to be seen through. The matte layer 5 can be made of a thermosetting resin with urethane bonding or an ionizing radiation-curable resin such as acrylic resin. Known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be used to form the matte layer 5. Alternatively, the matte layer 5 may be formed using a known coating apparatus.

[0033] (Surface protective layer) The surface protection layer 6 is a layer formed by printing on the upper surface UP of the matte layer 5. It is desirable that the surface protection layer 6 be made of a material that is transparent or semi-transparent enough to allow the pattern 41 of the pattern layer 4 to be seen through the matte layer 5. The surface protection layer 6 can be made of a thermosetting resin with urethane bonding or an ionizing radiation-curable resin such as acrylic resin. Known printing methods such as gravure printing, offset printing, flexographic printing, silkscreen printing, or inkjet printing can be used to form the surface protection layer 6. Furthermore, the surface protection layer 6 may be formed using a known coating apparatus.

[0034] It is preferable that the matte layer 5 and the surface protection layer 6 have different gloss levels. One method for creating a difference in gloss between the matte layer 5 and the surface protection layer 6 is to add a matting agent to the matte layer 5. By adding a matting agent to the matte layer 5, the gloss of the matte layer 5 can be made lower than the gloss of the surface protection layer 6. Alternatively, different amounts of matting agent may be added to the matte layer 5 and the surface protection layer 6 to the extent that a difference in gloss between the matte layer 5 and the surface protection layer 6 is created. By utilizing the optical illusion of the human eye, the pattern 41 formed on the pattern layer 4 can be made to appear visually three-dimensional.

[0035] The surface protective layer 6 has a covering layer 61 that covers the matte layer 5 and a convex portion 62 formed at a position synchronized with the pattern 41 of the pattern layer 4. "Synchronized with the pattern" means, for example, that if the pattern layer 4 has a wood grain pattern printed on it, the position where the convex portion 62 is formed when the decorative sheet 10 is viewed from the upper side (UP) coincides with the position of the wood grain pores.

[0036] The pattern 41 of the pattern layer 4 that matches the convex shape portion 62 is not limited to a wood grain pattern, but may also be a pattern such as a stone pattern or a sand pattern, and the position of characteristic colors or shapes in these patterns may coincide with the position where the convex shape portion 62 is formed when the decorative sheet is viewed from above.

[0037] The convex portion 62, which is synchronized with the pattern 41, may have a mutually exclusive distribution with respect to the characteristic color distribution and position of shapes in the pattern when the decorative sheet is viewed from above. For example, if a wood grain pattern is printed on the pattern layer 4, the surface protective layer 6 can be said to be synchronized with the pattern 41 of the pattern layer 4 even if the positions of the wood grain pores and the positions where the convex portion 62 is formed are mutually exclusive when the decorative sheet is viewed from above.

[0038] By forming the convex portion 62 at a position synchronized with the pattern 41 of the pattern layer 4, the difference in gloss between the matte layer 5 and the surface protection layer 6 can give the pattern 41 (for example, the vascular portion of a wood grain pattern) formed on the pattern layer 4 a visually three-dimensional effect. This makes it possible to provide a decorative sheet 10 with a wood grain pattern that is closer to natural wood.

[0039] In the technical field of this embodiment, decorative panels having decorative sheets are typically cut according to the shape of the area where they are to be used. In such cutting operations, conventional decorative sheets have the problem of being prone to peeling at the interface between the base paper layer and the thermoplastic resin layer.

[0040] The inventors, after diligently investigating the above problem, discovered that paper strength agents (internal paper strength agents) conventionally added to paper to improve its strength actually reduce the adhesive strength between the thermoplastic resin and the paper. Although paper strength agents reinforce the bonds between cellulose fibers by covering their surface, it is believed that the paper strength agents fill the spaces between the cellulose fibers, inhibiting the penetration of the thermoplastic resin (molten resin) into the spaces between the cellulose fibers and thus reducing the adhesive strength between the thermoplastic resin and the paper.

[0041] Based on this understanding, the inventors completed their invention by adding cellulose nanofibers to the base paper layer instead of paper strength agents. Cellulose nanofibers are finer than the fibers of the base paper and improve the strength of the base paper by intertwining with the fibers. In addition, unlike conventional paper strength agents, cellulose nanofibers do not inhibit the penetration of thermoplastic resin between the base paper fibers, thus making the adhesion between the base paper layer and the thermoplastic resin layer stronger. Furthermore, the fact that cellulose nanofibers are finer than conventional paper fibers contributes to a stronger adhesion between the base paper layer 1 and the thermoplastic resin layer 2 through an anchoring effect.

[0042] Cellulose nanofibers may be contained not only in the base paper layer 1 but also in the thermoplastic resin layer 2. By adding cellulose nanofibers to the thermoplastic resin layer 2, the adhesion between the thermoplastic resin layer 2 and the base paper layer 1 can be made stronger through the anchoring effect.

[0043] The thermoplastic resin layer 2 preferably contains 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more, of cellulose nanofibers per 100 parts by mass of the thermoplastic resin constituting the thermoplastic resin layer 2. Furthermore, the thermoplastic resin layer 2 preferably contains 40 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of the thermoplastic resin.

[0044] Next, the manufacturing methods for the decorative sheet 10 and the decorative panel 100 will be described. First, the manufacturing method of the decorative sheet 10 includes the steps of: applying corona treatment or ozone treatment to the upper side UP of the base paper layer 1, that is, the side on which the thermoplastic resin layer 2 is formed; forming the thermoplastic resin layer 2 on the upper side UP of the base paper layer 1; applying corona treatment to the upper side UP surface 2s of the thermoplastic resin layer 2; forming a pattern layer 4 on the upper side UP surface 2s of the thermoplastic resin layer 2 by printing; and forming a surface protection layer 6 on the upper side UP of the pattern layer 4.

[0045] In this way, the decorative sheet 10 of this embodiment is formed.

[0046] The manufacturing method for the decorative panel 100 includes a step of bonding the decorative panel base material 8 to the lower side LO of the decorative sheet 10. In this way, the decorative panel 100 of this embodiment is formed.

[0047] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the spirit of the present invention are also included. Furthermore, the components shown in the above-described embodiment and the following modifications can be combined as appropriate.

[0048] In the above embodiment, the surface protection layer 6 is formed at a position synchronized with the pattern 41 of the pattern layer 4, but the form of the surface protection layer is not limited thereto. The surface protection layer does not have to be formed at a position synchronized with the pattern 41 of the pattern layer 4.

[0049] In the above embodiment, the decorative sheet 10 includes a matte layer 5, but the form of the decorative sheet is not limited thereto. The decorative sheet does not need to include a matte layer 5.

[0050] In the above embodiment, the decorative sheet 10 includes a base coloring layer 3, but the form of the decorative sheet is not limited thereto. The decorative sheet does not need to include a base coloring layer 3. [Examples]

[0051] The present invention will be described in detail with reference to the following examples. The present invention is not limited to the following examples.

[0052] (Example 1) The base paper layer 1 contains cellulose nanofibers and has a basis weight of 45 g / m². 2 A base paper was prepared. Of the base paper layer 1, the upper UP surface, that is, the surface on which the thermoplastic resin layer 2 would be laminated, was subjected to corona treatment or ozone treatment, and polypropylene (PP) was laminated to a thickness of 16 μm by melt extrusion molding to form the thermoplastic resin layer 2.

[0053] Next, corona treatment was applied to the upper surface of the thermoplastic resin layer 2, and a base color layer 3 was formed by gravure printing. Then, a pattern layer 4 with a wood grain design was formed on the upper surface of the base color layer 3 by gravure printing. A matte layer 5 was formed on the upper surface of the pattern layer 4 by gravure printing using a urethane resin. A surface protective layer 6 was formed on the upper surface of the matte layer 5 by gravure printing using a urethane resin at a position corresponding to the wood grain pores of the pattern layer 4.

[0054] After laminating each layer from the base paper layer 1 to the surface protective layer 6, the laminated material was cured at 60°C for 96 hours to form the decorative sheet 10. Medium-density fiberboard (MDF) was bonded to the lower side LO of the decorative sheet 10 to form the decorative panel 100.

[0055] (Example 2-1) The decorative sheet 10 of Example 2-1 was formed by the same method as in Example 1, except that 0.1 parts by mass of cellulose nanofiber per 100 parts by mass of polypropylene (PP) was added to the thermoplastic resin layer 2.

[0056] (Example 2-2) The decorative sheet 10 of Example 2-2 was formed by the same method as in Example 1, except that 9.8 parts by mass of cellulose nanofiber per 100 parts by mass of polypropylene (PP) was added to the thermoplastic resin layer 2.

[0057] (Examples 2-3) The decorative sheet 10 of Example 2-3 was formed by the same method as in Example 1, except that 15 parts by mass of cellulose nanofiber per 100 parts by mass of polypropylene (PP) was added to the thermoplastic resin layer 2.

[0058] (Example 3) The decorative sheet 10 of Example 3 was formed in the same manner as in Example 1, except that a thermoplastic resin layer 2 was laminated to a thickness of 5 μm.

[0059] (Example 4) The decorative sheet 10 of Example 4 was formed in the same manner as in Example 1, except that a thermoplastic resin layer 2 was laminated to a thickness of 50 μm.

[0060] (Example 5) The base paper layer contains cellulose nanofibers and has a basis weight of 60 g / m². 2 Except for preparing the base paper, the decorative sheet 10 of Example 5 was formed in the same manner as in Example 1.

[0061] (Example 6) The base paper layer 1 contains cellulose nanofibers and has a basis weight of 50 g / m². 2 Except for preparing the base paper, the decorative sheet 10 of Example 6 was formed in the same manner as in Example 1.

[0062] (Comparative Example 1) As the base paper layer 1, a base paper with a basis weight of 45 g / m² that does not contain cellulose nanofibers was prepared, and the decorative sheet 10 of Comparative Example 1 was formed in the same manner as in Example 1, except for this. 2

[0063] (Comparative Example 2) As the base paper layer 1, a base paper with a basis weight of 45 g / m² that does not contain cellulose nanofibers was prepared, and the decorative sheet 10 of Comparative Example 2 was formed in the same manner as in Example 1, except that cellulose nanofibers were added to the thermoplastic resin layer 2. 2

[0064] (Experiment 1) A peel strength test was carried out on the decorative sheets of Examples 1 to 6 and Comparative Examples 1 and 2. In the peel strength test, the surface protection layer 6 side of the decorative sheet was bonded to a base material such as MDF with double-sided tape and reinforced with a 25 mm-wide cellophane tape so as not to break, and then the peel load (N) of the decorative sheet was measured with a load cell type tensile tester, and the peel load (N) and the peeled surface were observed and compared. The test speed during the tensile test was 200 mm / min, and the measurement width was 25 mm.

[0065] (Experiment 2) A cross-hatch tape test was carried out on the decorative sheets of Examples 1 to 6 and Comparative Examples 1 and 2. In the cross-hatch tape test, a decorative board was prepared by bonding the decorative sheet to a base material such as MDF with a vinyl acetate adhesive or the like, and a 1 mm square, 10 × 10 grid-like cut was made on the surface of the decorative sheet. A Nichiban cellophane tape was attached to the grid-like cut portion of the decorative sheet, peeled at an angle of 60 degrees, and the number of peeled squares in the 10 × 10 grid was counted to observe and compare the adhesion strength. When there were no peeled squares, it was judged as pass (〇), and when there was 1 or more peeled square, it was judged as fail (×).

[0066] (Experimental Results) The results of Experiments 1 and 2 are shown in Table 1. ​​In Experiment 1, Examples 1-6 showed better results compared to Comparative Examples 1 and 2. Examples with a base paper layer containing cellulose nanofibers showed improved peel strength in the peel strength test compared to the comparative examples with a base paper layer not containing cellulose nanofibers. Examples in which cellulose nanofibers were added to both the base paper layer and the thermoplastic resin layer showed improved peel strength compared to examples without the addition, and the peel strength improved as the amount of added cellulose nanofibers increased.

[0067] Furthermore, in Experiment 2, Examples 1-6 showed better results compared to Comparative Examples 1 and 2. In the examples with a base paper layer containing cellulose nanofibers, no peeling of the grid was observed, and no delamination of the decorative sheet occurred. In contrast, in the comparative examples with a base paper layer not containing cellulose nanofibers, peeling of the grid was observed, and delamination of the decorative sheet occurred.

[0068] [Table 1] [Explanation of symbols]

[0069] 100... Decorative board, 10... Decorative sheet, 8... Base material for decorative board, 1... Base paper layer, 2... Thermoplastic resin layer, 3... Undercoat coloring layer, 4... Pattern layer, 41... Pattern, 5... Matte layer, 6... Surface protection layer, 61... Coating layer, 62... Convex shape

Claims

1. The base paper layer, A thermoplastic resin layer provided on one surface of the base paper layer, Pattern layer, The surface protective layer and the following are provided in this order: The aforementioned base paper layer is a decorative sheet containing cellulose nanofibers.

2. The decorative sheet according to claim 1, wherein the thermoplastic resin layer contains cellulose nanofibers.

3. The decorative sheet according to claim 1 or 2, wherein the cellulose nanofiber is contained in the thermoplastic resin layer in an amount of 0.1 parts by mass or more.

4. The decorative sheet according to claim 1 or 2, wherein the base paper layer has a T-type peel strength of 130 gf / 15 mm or more.

5. The decorative sheet according to claim 1 or 2, wherein the thermoplastic resin layer contains polypropylene or polyethylene.

6. A matte layer provided above the patterned layer, The decorative sheet according to claim 1 or 2, further comprising a surface protective layer formed above the matte layer and in a position synchronized with the pattern of the patterned layer, and having a gloss different from that of the matte layer.

7. A decorative member manufactured using a decorative sheet according to claim 1 or 2 and a base material for a decorative member provided below the decorative sheet.

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