JPH11129426A - Decorative sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new decorative sheet which shows proper weatherability and molding/working properties required for the decorative sheet and is naturally perishable when it is discarded as a waste and left alone. SOLUTION: The decorative sheet S is a decoratively treated base material sheet 1 made up of a polylactic acid resin sheet composed mainly of poly-L- lactic acid, or the decoratively treated base sheet 1 on which a surface protecting layer 7 is laminated. The base material sheet 1 is degraded completely into water and carbonic acid gas by the activity of bacteria in the soil, so that the sheet 1 is friendly to global environments.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative sheet used for various decorations including interior materials.

[0002]

2. Description of the Related Art Conventionally, as this kind of decorative sheet, a sheet utilizing a sheet made of polyvinyl chloride resin has been mainly used. This polyvinyl chloride sheet is excellent in printability and embossing suitability, not only easy to process into a decorative sheet, but also excellent in post-processability such as V-cut and wrapping, and has the advantage of being inexpensive. .
However, this type of decorative sheet has drawbacks such as insufficient heat resistance and poor surface stain resistance due to bleeding of the plasticizer. Therefore, recently, as a material replacing the polyvinyl chloride resin, thermoplastic elastomers such as styrene, olefin, urethane, polyamide, and ester, EVA (ethylene vinyl alcohol copolymer), PET (polyethylene terephthalate), Various decorative sheets using an acrylic resin have been proposed.

[0003]

However, any of the decorative sheets using any of the above-mentioned materials has a problem that the resin remains permanently as garbage when discarded, which is not preferable from the viewpoint of protecting the natural environment. There is.

[0004] The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a decorative sheet having the necessary weather resistance and proper forming process, and furthermore, dispose of the sheet and leave it as it is. It is another object of the present invention to provide a new decorative sheet that disappears naturally.

[0005]

Means for Solving the Problems In order to achieve the above object, the decorative sheet of the present invention is obtained by subjecting a base sheet made of a polylactic acid-based resin sheet mainly composed of poly-L-lactic acid to a decorative treatment. It is characterized by the following.

[0006] Further, the decorative sheet of the present invention comprises poly-L-
A decorative treatment is performed on a base sheet made of a polylactic acid-based resin sheet containing lactic acid as a main component, and a surface protective layer is laminated on the base sheet.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polylactic acid-based resin constituting the base sheet is manufactured from starch, and the polylactic acid-based resin used in the present invention contains poly-L-lactic acid as a main component. As the poly-L-lactic acid, those having a weight average molecular weight of 100,000 or more, preferably 200,000 or more are used. If necessary, various additives such as an ultraviolet absorber, a light stabilizer, a fungicide, and a flame retardant are added to the polylactic acid-based resin.

The ultraviolet absorber and the light stabilizer are both added to impart weather (light) resistance to the base sheet (decorative sheet), and either one of them may be used alone, but usually both are mixed. To use. As the ultraviolet absorber, an organic type such as benzotriazole type, benzophenone type or salicylate type, or an inorganic type such as fine particle titanium dioxide or cerium oxide is used. As the light stabilizer, a hindered amine radical scavenger or the like is used. Both the ultraviolet absorber and the light stabilizer are added in an amount of about 0.1 to 1% by weight.

The base sheet may be stretched or unstretched. In the case of stretching, it may be uniaxial stretching or biaxial stretching, but usually it is biaxial stretching. The stretching ratio is preferably about 2 to 4 times. An unstretched base sheet is easily deformed plastically and has good moldability, but a stretched base sheet has high transparency, high elasticity, and excellent tensile strength and elongation.
Further, it is desirable to impart heat resistance and heat shrink resistance by performing a heat treatment (annealing) at about 80 to 120 ° C.
The thickness of the base sheet used in the present invention is 25 to 20.
It is about 0 μm.

The base sheet is subjected to a desired decoration treatment. As the decoration process, coloring by kneading a pigment or a dye, forming a decoration layer including a pattern of an ink picture layer or a metal layer,
An uneven pattern is formed. The decorative layer or the concavo-convex pattern may be formed on the front surface, the back surface, or both the front and back surfaces of the base sheet when the base sheet is transparent, but needs to be formed on the front side when the base sheet is opaque. When used as a decorative sheet, such as a backing sheet, to be adhered to the back surface of the adherend as it is, there is no need for decorative treatment.

In the case of coloring by kneading a pigment or dye, the coloring is made transparent or opaque (concealing) depending on the application. Examples of pigments include titanium white, zinc white, ultramarine, cobalt blue, red iron oxide, vermilion, graphite, titanium yellow, carbon black, and other inorganic pigments, quinacridone, and permanent red 4.
R, Isoindolinone, Hansa Yellow A, Phthalocyanine Blue, Indathrene Blue RS, Organic Pigments or Dyes such as Aniline Black, Metallic Pigments Made of Foil Powders such as Aluminum and Brass, Titanium Dioxide-Coated Mica, Basic Lead Carbonate A pearl luster (pearl) pigment made of foil powder or the like is used. In addition, extenders (fillers) such as calcium carbonate, silica (silicon dioxide), alumina (aluminum oxide), and barium sulfate are added as necessary.

In order to form a pattern with the ink picture layer,
Normal printing methods such as gravure printing, offset printing, letterpress printing, and silk screen printing can be used, but drawing may be used. The picture layer is formed by forming an ink composed of a resin binder and a pigment or a dye into an arbitrary pattern. Also, an ink layer on a peelable support sheet,
If necessary, a transfer sheet having an adhesive layer formed thereon is prepared in advance, and the ink layer formed on the transfer sheet is pressurized or a surface on which a pattern layer (ink picture layer) is formed by pressurization and heating. Transfer printing method, that is, a so-called transfer printing method. Examples of patterns include wood grain, stone grain, cloth grain, leather crest, characters, figures, and solid solids. As a resin binder of the ink, a two-component curable urethane resin, an acrylic resin, a cellulose resin, a vinyl chloride-vinyl acetate copolymer, or the like is used. The same pigments or dyes as described above are used.

The pattern of the metal layer is formed by vacuum-depositing a metal such as aluminum, chromium, gold, silver, and copper. Such a metal layer may be formed on the entire surface, or may be formed in a pattern (pattern). To form the pattern, a removal layer is formed by a water-soluble ink on a metal layer unnecessary portion. A known method such as vapor deposition of a metal over the entire surface from above and then washing with water to remove the metal layer immediately above the removal layer together with the above-mentioned removal layer. In addition, a so-called transfer printing method in which a metal layer formed in advance on a transfer sheet is transferred to a surface on which a pattern layer (metal layer) is formed can be used.

As a method of forming the uneven pattern, there are a hairline processing, a sand blast processing, an embossing processing and the like, and an uneven pattern having an uneven shape is formed on the base sheet by these methods.

The embossing is performed by using a hot-press type sheet-fed or rotary embossing machine to press the embossing plate against the surface of the heated and softened base sheet to form the uneven shape of the surface of the embossing plate. This is a method of forming a concavo-convex pattern. Examples of the concavo-convex pattern formed by the embossing include those expressing wood grain conduit grooves, wood grain wood texture, stone surface unevenness, fabric surface texture, satin finish, grain, hairline, and the like, or a combination thereof. The concave portions of the concavo-convex pattern are filled with a coloring ink as necessary by a known wiping method. As the coloring ink, urethane resin, acrylic resin, polyester resin,
A vehicle obtained by adding a pigment or a dye to another conventional vehicle is selected and used, but a two-liquid curing type having good adhesion and solvent resistance is preferable. Wiping may be performed by any of conventionally used wiping methods such as a doctor blade method and a roll coating method. According to these methods, the colored ink is applied to the entire surface of the concave and convex pattern, and then the ink of the convex portion is scraped off to leave the colored ink in the concave portion.

The form of the decorative sheet may be a single layer composed of only the base sheet as shown in FIG. 1, a two-layer composed of the base sheet and the surface protective layer as shown in FIG. There is a stack of more than one layer (not shown).

The decorative sheet S shown in FIG. 1A is obtained by adding a coloring agent 2 such as a pigment to a base sheet 1 and coloring the decorative sheet S. The decorative sheet S in FIG. An easy-adhesion layer 3 is provided, and a picture layer 4 (solid pattern or partial pattern) is formed thereon by printing. FIG. 1 (c)
The decorative sheet S has a concave and convex pattern formed of the concave portions 5 on the surface of the base material sheet 1. The decorative sheet S in FIG. 1D has the concave portions on the surface filled with the coloring agent 6 by wiping. .

The decorative sheet S shown in FIG. 2A has a pattern layer 4 formed on a base sheet 1 by printing, and a surface protective layer 7 is laminated thereon. In the decorative sheet shown in FIG. 2B, a pattern layer 4 is formed by printing on the surface of a base sheet 1 colored by adding a coloring agent 2 such as a pigment, and a surface protective layer 7 is laminated thereon. Things. It is preferable to use a polylactic acid-based resin as the surface protective layer 7 from the viewpoint of biodegradability.
However, other resins may be used in order to obtain desired surface properties. For example, a fluorine resin such as polyvinylidene fluoride, an acrylic resin such as polymethyl methacrylate, an olefin resin such as polypropylene, and an electron beam or ultraviolet curable acrylate-based or epoxy-based resin can be used. This surface protective layer 7 is formed by bonding a sheet formed in advance or applying a resin.

In the decorative sheet S shown in FIG. 2C, a pattern layer 4 is formed by printing on the surface of a base sheet 1 colored by adding a coloring agent 2 such as a pigment, and a surface protective layer 7 is formed thereon. Are laminated, and a decorative sheet having a concave-convex pattern formed by the concave portions 5 is embossed. Further, the decorative sheet S shown in FIG. 2D is obtained by filling the concave portions on the surface of the decorative sheet of FIG. 2C with the coloring agent 6 by wiping.
In the case of a decorative sheet having a two-layer laminated structure as shown in FIGS. 2A to 2D, the base sheet 1 on the back side used is a sheet stretched under the above-described conditions, and the surface protective layer 7 is It is preferable to use a non-stretched one made of a polylactic acid-based resin.

A preferred method of manufacturing the decorative sheet S as shown in FIG. 2 (c) is as follows. First, a base sheet 1 is manufactured by forming a polylactic acid-based resin into a stretched sheet, and printing and primer coating are performed on the base sheet 1 as necessary. Then, as shown in FIG. 3, a pressure roll (impression cylinder) 1
By extruding a polylactic acid-based resin as a surface protective layer 7 from a T-die 13 in a molten state while passing the substrate sheet 1 between the substrate sheet 1 and a cooling roll (embossing plate cylinder) 12, the surface protective layer is formed on the substrate sheet 1. Simultaneously with the lamination of the layers 7, the surface protection layer 7 is formed with an uneven pattern by the action of the cooling roll 12 also serving as the embossing plate. In the decorative sheet manufactured in this manner, since the surface protective layer 7 is not stretched, embossing is likely to occur due to plastic deformation, and since the base sheet 1 is stretched and has excellent tensile strength and elongation, V Processing aptitude such as cutting and lapping is good. In other words, this type of decorative sheet made of polylactic acid-based resin achieves both embossing properness (formation of good concavities and convexities) and tensile strength and elongation sufficient for bending such as V-cutting, which were originally difficult to achieve. Can be done.

The decorative sheet of the present invention can be laminated on another adherend (backing material). The adherend is the final product, and a decorative sheet may be laminated to make up the surface, or if necessary, may be applied to the back of the decorative sheet to reinforce the mechanical strength of the decorative sheet or to provide concealment. In some cases, bodies are stacked. When laminating on the adherend, the adhesive layer may be omitted if the decorative sheet itself can be adhered to the adherend (at a thermal melting point or the like). If the decorative sheet itself does not adhere to the adherend, an appropriate adhesive is used.

FIGS. 4 and 5 are sectional views showing the decorative sheet laminated on the adherend together with the adherend. FIG. 4 shows the decorative sheet S shown in FIG. 5 is laminated on a flat plate with an adhesive layer 9 interposed therebetween, and the one shown in FIG. Are laminated on the surface by a simultaneous molding lamination method (described later).

The object to be adhered may be a plate material of various materials (FIG. 4), a plate material such as a curved plate, a three-dimensionally shaped article (FIG. 5), or an article of various shapes such as a sheet (or film).
Examples of materials used for board materials, three-dimensionally shaped articles, and sheets (films) include wood veneer, wood plywood, particle board, wood board such as medium density fiber board (MDF), wood board such as wood fiber board, Metals such as iron and aluminum, acrylic resin, polycarbonate resin, ethylene / vinyl acetate copolymer, ethylene vinyl acetate, polyester resin, polystyrene, polyolefin resin, ABS, phenol resin, polyvinyl chloride, cellulose resin, rubber and other resins There is. Materials used exclusively as plate materials or three-dimensionally shaped articles include ceramics such as glass and porcelain, cement such as ALC (foamed lightweight concrete), and non-cement ceramic materials such as calcium silicate and gypsum. Materials used exclusively as a sheet (or film) include paper such as high-quality paper and Japanese paper, and nonwoven fabric or woven fabric made of fibers such as carbon, asbestos, potassium titanate, glass, and synthetic resin.

As a method of laminating a decorative sheet on these various adherends, for example, a method of laminating a plate-like substrate by pressing with a pressure roller via an adhesive layer, Japanese Patent Publication No. Sho 50
As described in JP-A-19132, JP-B-43-27488, etc., a decorative sheet is inserted between the male and female molds for injection molding, the molds are closed, and the molten resin is injected from the male gate. After filling and cooling, the decorative sheet is adhered and laminated on the surface simultaneously with the molding of the resin molded product, so-called simultaneous injection molding laminating method, JP-B-56-45768,
As described in Japanese Patent Publication No. 60-58014, etc.,
A so-called vacuum press lamination method in which a decorative sheet is opposed to or placed on the surface of a molded article with an adhesive layer therebetween, and the decorative sheet is laminated on the surface of the molded article by a pressure difference due to vacuum suction from the molded article side, JP-B-61-5895, JP-B-3
As described in JP-A-2666, etc., while supplying a decorative sheet through an adhesive layer in the long axis direction of a columnar substrate such as a cylinder and a polygonal column, a plurality of rollers having different directions are used to form a columnar substrate. A so-called lapping method in which a decorative sheet is sequentially adhered to a plurality of side surfaces constituting a body by pressure bonding, which is a so-called lapping method, disclosed in Japanese Utility Model Publication No. 15-31122, and Japanese Patent Laid-Open No. 48-47972.
As described in Japanese Patent Laid-Open Publication No. H10-15095, first, a decorative sheet is laminated on a plate-like base material via an adhesive layer, and then the decorative sheet and the plate-like base material are provided on the surface of the plate-like base material opposite to the decorative sheet. Cut into a V-shaped or U-shaped groove reaching the interface with the material, then apply an adhesive in the groove, and then bend the groove to form a box or columnar body. There are V-cut and U-cut processing methods.

In particular, as the method of attaching the decorative sheet of the present invention to a three-dimensional object having irregularities, of the above methods, simultaneous injection molding lamination, vacuum press lamination, lapping, V-cut, and the like are preferable.

The decorative sheet of the present invention is used for various applications by laminating on various adherends and subjecting it to a predetermined molding process. For example, building interiors such as walls, ceilings, floors, doors, window frames,
Door frames, handrails and other surface fittings for furniture, furniture such as chests,
Surface makeup such as cabinets for OA equipment, vehicle interiors such as cars and trains, aircraft and ship interiors, and window glass makeup.

[0027]

【Example】

(Example 1) A substrate sheet was produced as follows. That is, to 100 parts by weight of a poly-L-lactic acid-based resin (weight-average molecular weight: 200,000), 10 parts by weight of a coloring pigment, titanium white, and 0.5 parts by weight of a benzotriazole-based ultraviolet absorber were added. The product is biaxially stretched at an elongation of 3 times,
Heat treatment was performed at 0 ° C. to form a film having a thickness of 80 μm.

Next, a pattern was printed on the base sheet.
More specifically, a two-component curable polyurethane resin consisting of hexamethylene diisocyanate and acrylic polyol is used as a binder, and red pigment is used as a pigment. The wood grain pattern was printed to form a picture layer.

Then, 0.5 parts by weight of a benzotriazole ultraviolet absorber and 0.5 parts by weight of a hindered amine radical scavenger are added to 100 parts by weight of a poly-L-lactic acid resin (weight average molecular weight: 200,000). Using this composition, as shown in FIG. 3, this composition was extruded from a T-die in a molten state, and was laminated on the printing surface of the substrate sheet to a thickness of 60 μm, and at the same time, the surface of the oak material was cooled by a cooling roll also serving as an embossing plate. The concave and convex of the conduit groove was embossed. Next, a sepia colored ink (binder is acrylic resin,
Pigment was filled with wiping method. Finally, the topcoat layer was coated with a thickness of 3 μm to produce a decorative sheet. This overcoat layer was formed using a composition obtained by using a two-part curable urethane resin composed of hexamethylene diisocyanate and an acrylic polyol as a binder, and adding 100 parts by weight of the binder and 3 parts by weight of a silica pigment as a matting agent. .

(Example 2) The decorative sheet produced in Example 1 was bonded to a 2.5 mm thick Rawan plywood with an adhesive to form a decorative sheet. The adhesive used was vinyl acetate 2
It is a liquid-curable emulsion (using isocyanate as a curing agent).

(Evaluation) Weather resistance 1 measured with a carbon arc lamp type sunshine weatherometer.
An exposure test of irradiating for 000 hours was performed. The conditions were a black panel temperature of 63 ° C. and a rain cycle of 18 minutes / 120 minutes. Then, the retention rate of the tensile strength after the exposure was measured, and the discoloration was visually observed. As a result, the decorative sheet of Example 1 had a retention rate of the tensile strength of 70%, and a noticeable change in the external appearance was observed. I couldn't.

Degradability The decorative sheet of Example 1 was buried in the soil of Miyoshi-cho, Iruma-gun, Saitama, and excavated after standing for 6 months from April to September.
Then, when the external appearance was visually observed, decomposition was progressing, and the sheet did not retain its original shape, and the sheet was fragmented. In addition, the molecular weight retention rate of the collected pieces of the decorative sheet was measured for reference and found to be 40%.

[0033]

As described above, the decorative sheet of the present invention has the necessary weather resistance and the appropriate forming process for the decorative sheet. It is not biodegraded and deteriorated by water or bacteria, and when it is disposed of and left in contact with the soil or left in the soil, its base sheet is completely decomposed into water and carbon dioxide by the action of microorganisms in the soil. Because it disappears, it is favorable for the global environment.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a decorative sheet according to the present invention.

FIG. 2 is a sectional view showing another example of the decorative sheet according to the present invention.

FIG. 3 is an explanatory diagram of a method for manufacturing a decorative sheet having a surface protective layer provided with a concavo-convex pattern.

FIG. 4 is a sectional view showing a decorative sheet laminated on an adherend together with the adherend.

FIG. 5 is a cross-sectional view showing a decorative sheet laminated on an adherend together with the adherend.

[Explanation of symbols]

 S Decorative sheet 1 Base sheet 2 Colorant 3 Easy adhesion layer 4 Picture layer 5 Depression 6 Colorant 7 Surface protective layer 8 Adherend 9 Adhesive 10 Adherend 11 Pressure roll 12 Cooling roll 13 T die

Claims (4)

[Claims] 1. A decorative sheet obtained by subjecting a base sheet made of a polylactic acid-based resin sheet mainly composed of poly-L-lactic acid to a decorative treatment. 2. The decorative sheet according to claim 1, wherein the stretched polylactic acid-based resin sheet is used as a base sheet. 3. A decorative sheet comprising a base sheet made of a polylactic acid-based resin sheet containing poly-L-lactic acid as a main component, which is subjected to a decoration treatment, and a surface protective layer is laminated on the base sheet. 4. The decorative sheet according to claim 3, wherein the stretched polylactic acid-based resin sheet is used for the base sheet, and the unstretched polylactic acid-based resin is used for the surface protective layer.