JP7047299B2 - Decorative sheet and decorative material using it - Google Patents

Description

The present invention relates to a decorative sheet, and more particularly to a decorative sheet exhibiting excellent post-workability such as wrapping aptitude and bendability and excellent weather resistance, and a decorative member using the same.

Most of the decorative boards and decorative members used for the interior and exterior of buildings are manufactured by laminating a decorative sheet on the surface of a base material such as a wood-based base material, an inorganic-based base material, or a metal plate. ing. As the decorative sheet, a base sheet on which a wood grain pattern, a geometric pattern, or the like is printed and formed on which a transparent surface protective layer is formed is generally used.

Conventionally, vinyl chloride resin has been widely used as the material for decorative sheets, but since toxic gas such as hydrogen chloride is generated during combustion, decorative sheets using polyolefin-based resin materials that do not contain chlorine are often used. It has come to be.

The method for producing a polyolefin decorative sheet described in Patent Document 1 is a method for producing a polyolefin decorative sheet, which prevents the adhesion between the transparent polyolefin resin layer and the surface protective layer from deteriorating over time and has little change in various physical properties over time. Is a proposal.

The method for producing a polyolefin decorative sheet described in Patent Document 1 attempts to solve the problem that the adhesiveness between the transparent polyolefin resin layer conventionally used as the transparent protective layer and the surface protective layer applied to the surface is not sufficient. However, it cannot be said that the post-workability such as bending property and wrapping processability is sufficient.

The decorative sheet described in Patent Document 2 proposes a decorative sheet having a surface protective layer having excellent abrasion resistance, stain resistance, adhesion to a polyolefin resin, and blocking property.

The decorative sheet described in Patent Document 2 attempts to use a water-based coating agent instead of the conventional solvent-type coating agent as the surface protective layer, but it is also bent in terms of weather resistance. Post-workability such as property and suitability for wrapping process was also insufficient.

The purpose of the surface protective layer used for the outermost surface of the decorative sheet is to improve weather resistance, scratch resistance, stain resistance, adjustment of surface gloss, etc. Among them, the improvement of weather resistance is the surface protective layer. It can be said that it is the biggest role.

In recent years, as long-term warranty for housing has become common sense, improving the weather resistance of decorative sheets has become a major issue. Since the surface protective layer itself needs to have excellent weather resistance in order to improve the weather resistance of the decorative sheet, an acrylic resin is often used as the surface protective layer, and in order to further improve the weather resistance, the surface protective layer is used. It is common to add a weather resistant agent, that is, an ultraviolet absorber or a radical scavenger.

The decorative sheet described in Patent Document 3 is a study on an ultraviolet absorber to be blended in a surface protective layer for the purpose of improving the weather resistance of the decorative sheet, and is a hydroxyphenyltriazine-based ultraviolet absorber as an ultraviolet absorber. Is added in an amount of 1 to 30 parts.

The decorative sheet described in Patent Document 3 is superior in weather resistance to conventional ones, but is not sufficient in terms of post-workability such as bending property and wrapping process suitability, and therefore is used for applications involving post-processing. When used, sufficient weather resistance could not be exhibited due to cracks in the processed portion.

It is necessary to increase the amount of weathering agent added in order to further improve the weathering resistance, but there is a concern about bleeding out depending on the type of weathering agent, and it also leads to cost increase, so there is a limit to increasing the amount added. there were. Even if these problems can be avoided, the performance will be deactivated due to the decomposition of the weathering agent itself over time, the initial performance will not be obtained, and long-term weather resistance will not be obtained. was there. Further, when there is post-processing such as bending, there is a concern that cracks will occur in the bent portion and deterioration will be accelerated from the cracked portion.

The decorative sheet described in Patent Document 4 is a decorative sheet using a base sheet also made of a polyolefin resin, and proposes a decorative sheet having excellent weather resistance, solvent resistance, processing aptitude and scratch resistance. Is.

The decorative sheet described in Patent Document 4 is described to exhibit excellent performance in each evaluation item, but since an electron beam curable transparent resin must be used as the surface protective layer, the resin is used. It was difficult to implement because of its high price and the need for expensive and large-scale production equipment.

Japanese Unexamined Patent Publication No. 2005-084881 JP-A-2007-118584 Japanese Unexamined Patent Publication No. 2011-16277 Japanese Unexamined Patent Publication No. 2008-238444

The problem to be solved by the present invention is that by imparting flexibility to the surface protective layer, it is excellent in post-processability such as bending property and wrapping processability, and as a result, the processed portion becomes a factor such as ultraviolet rays and wind and rain. It is a proposal of a decorative sheet having excellent weather resistance and a decorative member using the decorative sheet, which does not deteriorate in design even when exposed for a long period of time.

As a means for solving the above problems, the invention according to claim 1 is a decorative sheet having a surface protective layer on the outermost surface, and the surface protective layer is an acrylic resin crosslinked with an isocyanate curing agent. Consisting only of the composition
The acrylic resin composition is composed of a first acrylic resin having a glass transition temperature of 1 ° C. or higher and a second acrylic resin having a glass transition temperature of less than 1 ° C. The content of the second acrylic resin in the resin composition is 1% by mass or more and 30% by mass or less.
It is a decorative sheet characterized by being.

The decorative sheet according to the present invention uses an acrylic resin composition containing 1% by mass or more and 30% by mass or less of an acrylic resin having a glass transition temperature of less than 1 ° C as a main component as a surface protective layer. , The surface protective layer is given flexibility and the post-processing suitability is improved.

The invention according to claim 2 is the decorative sheet according to claim 1, wherein the surface protective layer contains a filler.

The invention according to claim 3 is characterized in that the thickness of the surface protective layer is 2 μm or more and 20 μm or less, and the total thickness of the decorative sheet is 40 μm or more and 300 μm or less. It is a decorative sheet described in.

The invention according to claim 4 is the decorative sheet according to any one of claims 1 to 3, wherein an uneven pattern is formed on the surface of the decorative sheet.

The invention according to claim 5 is a decorative member characterized in that a wood-based or metal-based substrate is provided on the back surface of the decorative sheet according to any one of claims 1 to 4.

The invention according to claim 6 is the decorative member according to claim 5, wherein the substrate has a three-dimensional structure.

The decorative sheet according to the present invention is a decorative sheet having a surface protective layer on the outermost surface, and the surface protective layer contains an acrylic resin composition as a main component and is crosslinked with an isocyanate curing agent, and the acrylic resin. Since the composition contains 1% by mass or more and 30% by mass or less of an acrylic resin having a glass transition temperature of less than 1 ° C., it has excellent post-processing suitability such as bending and wrapping processing, and is suitable for post-processing such as bending and wrapping. Cracks are unlikely to occur.

Therefore, even after processing the decorative sheet into a decorative member having a three-dimensional shape, which is the final usage form of the decorative sheet, the weather resistance inherent in the decorative sheet is not impaired.

When the surface protective layer contains a filler as in the invention according to claim 2, not only the gloss of the surface can be adjusted to an appropriate value, but also the surface protective layer can be selected by selecting the material of the filler. The durability of itself can be improved.

Further, as in the invention according to claim 3, when the thickness of the surface protective layer is 2 μm or more and 20 μm or less and the total thickness of the decorative sheet is 40 μm or more and 300 μm or less, the post-processing suitability and durability The cosmetic sheet has a good balance of cost and is easy to use.

When an uneven pattern is formed on the surface of the decorative sheet as in the invention of claim 4, it is possible to exhibit a higher degree of design by appropriately selecting the pattern and the uneven pattern. can.

As in the invention according to claim 5 or 6, a decorative member having a wood-based or metal-based substrate on the back surface of the decorative sheet, and particularly the substrate having a three-dimensional structure, is the present invention. It is possible to make a decorative member that fully utilizes the characteristics of the decorative sheet according to the above.

FIG. 1 is a schematic cross-sectional view showing a layer structure in one embodiment of the decorative sheet according to the present invention. FIG. 2 is a schematic cross-sectional view showing a layer structure in an example of a decorative member in which the decorative sheet shown in FIG. 1 is attached to a base material. FIG. 3 is a schematic cross-sectional view showing an example of a decorative member using the decorative sheet according to the present invention, in which the decorative sheet is bonded to a metal plate and bent. FIG. 4 is a schematic cross-sectional view showing another example of the decorative member using the decorative sheet according to the present invention, in which the decorative sheet is bonded to a wooden base material, V-cut, and bent. be. FIG. 5 is a schematic cross-sectional view showing another example of the decorative member using the decorative sheet according to the present invention, in which the decorative sheet is wrapped on a wooden base material.

Hereinafter, the decorative sheet according to the present invention and the decorative member using the decorative sheet will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a layer structure in one embodiment of the decorative sheet according to the present invention, and FIG. 2 is a layer in an example of a decorative member in which the decorative sheet shown in FIG. 1 is bonded to a base material. It is sectional drawing which showed the structure.

The decorative sheet 1 according to the present invention is a decorative sheet having a surface protective layer 7 on the outermost surface, and the surface protective layer 7 contains an acrylic resin composition as a main component and is crosslinked with an isocyanate curing agent. The based resin composition is characterized by containing 1% by mass or more and 30% by mass or less of an acrylic resin having a glass transition temperature of less than 1 ° C.

In the example shown in FIG. 1, the pattern layer 4 is printed and formed on the surface of the colored thermoplastic resin layer 3, and the transparent thermoplastic resin layer 6 is laminated on the pattern layer 4 via the adhesive resin layer 5. Further, a surface protective layer 7 is formed on the surface of the transparent thermoplastic resin layer 6.

In this example, the primer layer 8 is provided on the back surface of the colored thermoplastic resin layer 3. The primer layer 8 is applied for the purpose of improving the adhesiveness when the decorative sheet 1 is adhered to the base material.

Further, in this example, the uneven pattern 10 is formed on the surface of the decorative sheet 1. The uneven pattern 10 is formed on the transparent thermoplastic resin layer 6 and the surface protective layer 7 provided on the transparent thermoplastic resin layer 6.

The colored thermoplastic resin layer 3 includes olefin resins such as polyethylene (PE) resin and polypropylene (PP) resin, vinyl chloride (PVC) resin, vinyl chloride vinyl acetate copolymer, and acrylonitrile styrene copolymer (AS). , Amorphous polyethylene terephthalate (A-PET) resin, nylon (NY), thermoplastic elastomer (TPE) and other base resins with colored pigments and various processing aids such as lubricants and stabilizers added to the resin composition. can.

When the bendability of the decorative sheet and the stretchability during post-processing are important, a relatively flexible plastic film such as PE, TPE, or PVC is used.

On the colored thermoplastic resin layer 3, a pattern layer 4 such as a wood grain pattern, a stone grain pattern, a cloth pattern, and an abstract pattern is generally printed and formed. Printing can be done by printing a continuous pattern using the gravure rotary printing method so that it can be cut anywhere.

Depending on the material of the colored thermoplastic resin layer 3, if the surface of the colored thermoplastic resin layer 3 is subjected to a corona discharge treatment prior to printing, the adhesion of the printing ink can be improved.

As the printing ink used for the pattern layer 4, an ink using an appropriate binder depending on the material of the colored thermoplastic resin layer 3 is used. When the colored thermoplastic resin layer 3 is a polyolefin-based ink, a urethane resin-based ink having high adhesion is preferably used.

A transparent thermoplastic resin layer 6 is provided on the pattern layer 4. The transparent thermoplastic resin layer 6 protects the pattern layer 4 and improves the wear resistance of the decorative sheet, and at the same time, gives depth to the pattern and contributes to the improvement of the design.

Examples of the transparent thermoplastic resin layer 6 include olefin resins such as polyethylene (PE) resin and polypropylene (PP) resin, vinyl chloride (PVC) resin, vinyl chloride vinyl acetate copolymer, and acrylonitrile styrene copolymer (AS). , Amorphous polyethylene terephthalate (A-PET) resin, nylon (NY), thermoplastic elastomer (TPE) and other base resins, various processing aids such as lubricants and heat stabilizers, as well as UV absorption for the purpose of improving weather resistance. A resin composition to which an agent, a light stabilizer, or the like is added can be used.
As the transparent thermoplastic resin layer 6, a thermoplastic resin of the same type as the thermoplastic resin used for the colored thermoplastic resin layer 3 is often used, but it is not always limited.
As in the example shown in FIG. 1, the adhesive resin layer 5 may be provided for the purpose of enhancing the adhesion between the pattern layer 4 and the transparent thermoplastic resin layer 6. When a PP resin is used as the transparent thermoplastic resin layer 6, a polyolefin-based adhesive resin having a polar group introduced into the molecular chain can be used as the adhesive resin layer 5.

On the other hand, when the PET resin is used as the transparent thermoplastic resin layer 6, a polyester-based adhesive resin having a polar group introduced into the molecular chain can be used as the adhesive resin layer 5.

The performance of these adhesive resins can be maximized by co-extruding two layers of the transparent thermoplastic resin onto the pattern layer surface at the same time. An adhesive layer may be further provided between the pattern layer 4 and the adhesive resin layer 5.

An uneven pattern 10 can be formed on the transparent thermoplastic resin layer 6. When the transparent thermoplastic resin layer 6 is supplied as a film, the uneven pattern 10 adopts a method in which the transparent thermoplastic resin layer 6 is bonded to the colored thermoplastic resin layer 3 and then reheated and pressed against the embossed roll. Be done.

On the other hand, when the transparent thermoplastic resin layer 6 is formed by the extrusion laminating method from the T die, the extrusion laminating simultaneous embossing method using the cooling roll as the embossing roll is effective because the production process is omitted.

A surface protective layer 7 is formed on the surface of the transparent thermoplastic resin layer 6. The surface protective layer 7 is the outermost layer of the decorative sheet 1 and is an important layer that determines various performances of the decorative sheet 1. That is, the surface is stain resistant and chemical resistant, the surface is glossy, slippery, scratch resistant, light resistant, weather resistant and the like.

Acrylic resin-based transparent resin compositions have been widely used to achieve these various performances at a high level. However, conventionally, a hard resin having a high glass transfer point temperature has been used from the viewpoint of emphasizing scratch resistance and the like. Tend to be.

However, when a hard resin is used for the surface protective layer 7, when the decorative sheet is subjected to post-processing such as bending or wrapping, fine cracks are generated in the surface protective layer, and if the surface protective layer is immediately after processing, Even if it was not visually recognized, it was found that when it was used for a long period of time, it may be discovered as a poor weather resistance of the processed part.

As a method for imparting flexibility to the surface protective layer 7, the acrylic resin composition contains 1% by mass or more and 30% by mass or less of an acrylic resin having a glass transition temperature of less than 1 ° C. to post-process the decorative sheet. It was found that the improvement of the property and the improvement of the weather resistance were achieved accordingly.
The acrylic resin-based surface protective layer 7 is formed by applying a two-component curable resin composition, which is cured by a cross-linking reaction between an acrylic polyol resin and an isocyanate curing agent, onto the surface of a transparent thermoplastic resin layer. .. As the coating method in this case, a coating method such as a gravure coater, a roll coater, or a kiss coater is used.

By adding a filler to the surface protective layer 7, the gloss of the surface is adjusted, and at the same time, there is an effect of improving the slipperiness and scratch resistance of the surface. As the filler, in addition to the most commonly used silica fine powder, organic resin fine powder such as acrylic resin beads and urethane resin beads can also be used.

In addition to the above, paint additives such as lubricants, leveling agents, and dispersants can be appropriately added to the coating agent for forming the surface protective layer 7. Further, an ultraviolet absorber or a light stabilizer can be added for the purpose of further improving the weather resistance and the light resistance.

In the example shown in FIG. 1, the primer layer 8 is provided on the back surface of the colored thermoplastic resin layer 3. The primer layer 8 enhances the adhesiveness between the decorative sheet 1 and the base material 2, and when the colored thermoplastic resin layer 3 is a polyolefin resin or the like, poor adhesion is likely to occur, so it is preferable to provide the primer layer 8. ..

The primer layer 8 may be prepared by adding a matting agent such as silica to the two-component curable acrylic urethane resin paint for the purpose of improving the adhesiveness by roughening the surface and for the purpose of preventing blocking when the primer layer 8 is wound. good.

FIG. 2 is a schematic cross-sectional view showing the layer structure of the decorative member 20 in which the decorative sheet 1 shown in FIG. 1 is attached to the base material 2. In this example, the decorative sheet 1 is bonded to the surface of the plate-shaped base material 2 by the adhesive layer 9 to form a decorative board. The base material 2 includes wood base materials such as plywood, medium density fiberboard (MDF), high density fiberboard (hard board), and particle board, as well as metal plates such as steel plates and aluminum plates, slate plates, and calcium silicate. An inorganic base material such as a board is used. The adhesive is appropriately selected according to the type of the base material.

FIG. 3 is a schematic cross-sectional view showing an example of a decorative member 20 using the decorative sheet 1 according to the present invention, in which the decorative sheet 1 is bonded to a metal plate and bent by post-processing. be. If the length direction is not very long, it can be molded using a press machine equipped with a blade with a right-angled tip and a V-shaped receiver, but it should be continuously molded using a roll forming machine. You can also. According to this processing method, there is no restriction in the length direction of the decorative member 20.

Regardless of which processing method is used, the decorative sheet at the corner portion is stretched by a considerable amount. Since the stretched amount is greatly stretched toward the outside of the corner portion, that is, the surface side of the decorative sheet, the surface protective layer 7 which is the outermost surface of the decorative sheet 1 is greatly stretched.

At this time, if the glass transition temperature (Tg) of the resin composition constituting the surface protective layer 7 is high, fine cracks are generated in the corner portions. Cracks may be visible to the naked eye, but they may not be visible to the naked eye. Further, even if cracks do not occur immediately after processing, cracks may occur over time or after being exposed to wind and rain.

If cracks occur in the surface protective layer 7, the light resistance and weather resistance originally possessed by the decorative sheet 1 cannot be sufficiently exhibited, and as a result, it is determined that the durability is inferior. In the decorative sheet according to the present invention, the post-processability is improved, so that the original weather resistance and the like of the decorative sheet 1 are fully exhibited.

FIG. 4 is a schematic cross-sectional view showing another example of the decorative member 20 using the decorative sheet 1 according to the present invention, in which the decorative sheet 1 is bonded to the wood substrate 2 and V-cut is applied. It is a bent one. According to such a processing method, a wooden decorative member having various cross-sectional shapes can be manufactured, and it is used as a building material for a door, a door frame, a window frame, etc. used indoors. Even in such a processing method, the behavior of the decorative sheet at the corner portion is the same as that of the decorative member shown in FIG.

FIG. 5 is a schematic cross-sectional view showing another example of the decorative member 20 using the decorative sheet 1 according to the present invention, in which the decorative sheet 1 is wrapped around a wooden base material 2. The wrapping process is different from the roll forming process described above, and is a method of continuously laminating a decorative sheet on the surface of a long wood base material 2 which has been previously processed into a predetermined cross-sectional shape.

According to this method, a long decorative member 20 having a complicated irregular cross section can be manufactured. This processing method is also the same in that the outermost surface of the decorative sheet 1 is greatly stretched at the corners and the like.

In addition, although not shown in particular, a decorative sheet is overlaid on a base material processed into a three-dimensional three-dimensional shape using a vacuum forming machine, or conversely, a concave surface is formed on the back surface of the decorative sheet by vacuum forming in advance. There are various post-processing such as a method of injecting a foamed resin composition into a concave surface after molding. Regardless of the post-processing, as long as the flat decorative sheet is processed into a three-dimensional shape, a stretching force is always applied to the outermost surface of the decorative sheet, so the post-processing suitability of the decorative sheet is improved. As a substitute property to be measured, a tensile test of a decorative sheet is useful. Hereinafter, the decorative sheet according to the present invention will be specifically described based on Examples.

<Example 1>
As the colored thermoplastic resin layer, a colored polyethylene resin sheet having a thickness of 55 μm was used, and one surface was subjected to a corona discharge treatment, and then the pattern layer was printed using a urethane resin-based printing ink. A transparent adhesive resin layer and a transparent thermoplastic resin layer were formed on the pattern layer via a urethane resin-based adhesive layer so as to have a thickness of 70 μm by coextrusion using a T-die.

A surface protective layer containing acrylic resin as a main component was formed on the surface of the transparent thermoplastic resin layer. As the surface protective layer, 9 parts by weight of an acrylic resin having a Tg of -17 ° C. and 10 parts by weight of an isocyanate resin curing agent (both in terms of solid content) were mixed with 81 parts by weight of the main acrylic resin. In this compounding ratio, NCO / OH = 1.0.

The back surface of the decorative sheet was subjected to a corona discharge treatment, and then a primer layer was formed so as to have a thickness of 1 μm.

<Comparative Example 1>
In the resin formulation of the surface protective layer, the decorative sheet was prepared in the same manner as in Example 1 except that the low Tg acrylic resin was not added and the isocyanate resin curing agent was 10 parts by weight with respect to 90 parts by weight of the main acrylic resin. Created.

<Comparative Example 2>
In the resin compounding of the surface protective layer, a decorative sheet was prepared in the same manner as in Example 1 except that the low Tg acrylic resin was 36 parts by weight and the isocyanate resin curing agent was 10 parts by weight with respect to 54 parts by weight of the main acrylic resin.

The three types of decorative sheets prepared above were subjected to a tensile test as a substitute property for post-processability and a blocking test as an evaluation of actual productivity. The results are shown in Table 1.

From the results in Table 1, it can be seen that the post-processability is inferior in Comparative Example 1 to which the low Tg resin is not added, and that Comparative Example 2 in which the low Tg resin exceeds 30% is not suitable for actual production.

1 ... Decorative sheet 2 ... Base material 3 ... Colored thermoplastic resin layer 4 ... Picture layer 5 ... Adhesive resin layer 6 ... Transparent thermoplastic resin layer 7 ... Surface protection Layer 8 ... Primer layer 9 ... Adhesive layer 10 ... Concavo-convex pattern 20 ... Decorative member

Claims (6)

A decorative sheet having a surface protective layer on the outermost surface, wherein the surface protective layer is composed only of an acrylic resin composition crosslinked with an isocyanate curing agent .
The acrylic resin composition is composed of a first acrylic resin having a glass transition temperature of 1 ° C. or higher and a second acrylic resin having a glass transition temperature of less than 1 ° C. A decorative sheet characterized in that the content of the second acrylic resin in the resin composition is 1% by mass or more and 30% by mass or less. The decorative sheet according to claim 1, wherein the surface protective layer contains a filler. The decorative sheet according to claim 1 or 2, wherein the surface protective layer has a thickness of 2 μm or more and 20 μm or less, and the total thickness of the decorative sheet is 40 μm or more and 300 μm or less. The decorative sheet according to any one of claims 1 to 3, wherein an uneven pattern is formed on the surface of the decorative sheet. A decorative member comprising a wood-based or metal-based base material on the back surface of the decorative sheet according to any one of claims 1 to 4. The decorative member according to claim 5, wherein the base material has a three-dimensional structure.

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