JP3900321B2 - Decorative sheet adherend - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of the decorative sheet used for various decorations including the interior material.
[0002]
[Prior art]
Conventionally, as this type of decorative sheet, a sheet using a sheet made of a polyvinyl chloride resin has been mainly used. This polyvinyl chloride-based sheet is excellent in printability and embossability, is easy to process into a decorative sheet, has excellent post-processability such as V-cut and lapping, and has the advantage of being inexpensive. . However, this type of decorative sheet has drawbacks such as insufficient heat resistance and poor surface contamination resistance due to plasticizer bleeding. Therefore, recently, as an alternative to 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 acrylic resin have been proposed.
[0003]
[Problems to be solved by the invention]
By the way, the decorative sheet using any of the above-mentioned materials has a problem that when discarded, the resin remains as waste as it is, which is not preferable from the viewpoint of protecting the natural environment.
[0004]
The present invention has been made in view of the above-mentioned problems, and its object is to provide weather resistance and molding processability necessary for a decorative sheet, and to be disposed of after being discarded. Another object is to provide an adherend using a new decorative sheet that disappears naturally.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the decorative sheet adherend of the present invention is obtained by drawing a polylactic acid-based resin mainly composed of poly-L-lactic acid having a weight average molecular weight of 100,000 or more into a stretched sheet and further heat-treating it. On the base sheet, a transparent surface protection sheet formed by stretching a polylactic acid-based resin mainly composed of poly-L-lactic acid having a weight average molecular weight of 100,000 or more and further heat-treating is laminated, and at least A decorative sheet adherend formed by laminating a decorative sheet subjected to a decoration treatment on either a base sheet or a surface protective sheet, and a decorative sheet in a plate-shaped base material in which the decorative sheet is laminated via an adhesive layer After cutting a groove having a V-shaped or U-shaped cross section at a depth reaching the interface between the decorative sheet and the plate-like base material, and applying an adhesive into the groove A box or columnar body by bending a plate-like substrate at the groove It is characterized in that the.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The polylactic acid resin constituting the base sheet and the surface protective sheet is produced from starch, and the polylactic acid resin used in the present invention contains poly-L-lactic acid as a main component. As this 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, an antifungal agent and a flame retardant are added to the polylactic acid resin.
[0007]
Both the ultraviolet absorber and the light stabilizer are added for imparting weather resistance (light) properties to the decorative sheet, and either of them may be used alone, but usually both are used in combination. As the ultraviolet absorber, organic ones such as benzotriazole, benzophenone and salicylate, or inorganic ones such as fine particle titanium dioxide and cerium oxide are used. As the light stabilizer, hindered amine radical scavengers such as bis- (2,2,6,6-tetramethyl-4-piperidyl) sebacate are used. Both the ultraviolet absorber and the light stabilizer are added in an amount of about 0.1 to 1% by weight.
[0008]
Although the base sheet and the surface protective sheet can be used even if they are non-stretched, they are preferably stretched when used for molding processing applications such as V-cut processing. In the case of stretching, it may be uniaxial stretching or biaxial stretching, but is usually biaxial stretching. The stretching ratio is preferably about 2 to 4 times. An unstretched polylactic acid resin sheet is easily plastically deformed and has good moldability for embossing by embossing, but has insufficient strength and elongation and is not suitable for bending processing such as V-cut processing. On the other hand, the stretched polylactic acid-based resin sheet has high transparency, high elastic modulus, and excellent tensile strength and elongation. Therefore, it is suitable for bending processing aptitude such as V-cut processing and drawing processing aptitude. Furthermore, it is desirable to impart heat resistance and heat shrinkage resistance by heat treatment (annealing) at about 80 to 120 ° C. And the thickness of the base material sheet used by this invention is about 25-200 micrometers. The base sheet is usually colored (this is also one of the decoration processes described later) in order to express the basic color of the entire decorative sheet. The coloring may be transparent or opaque (hidden). However, in the case where the decorative sheet itself is required to be transparent, such as a decorative sheet for window glass decoration, it may be colorless and transparent. The surface protective sheet is transparent (colorless or colored) in order to make use of the color tone of the underlying base material sheet.
[0009]
Desired decoration treatment is applied to at least one of the base sheet and the surface protective sheet. Examples of the decoration treatment include coloring by kneading a pigment or dye, formation of a decoration layer composed of a pattern of an ink picture layer or a metal layer, formation of an uneven pattern, and the like. 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.
[0010]
When coloring by kneading a pigment or dye, it is set to transparent coloring or opaque (concealing) coloring according to the use. Examples of pigments include titanium white, zinc white, ultramarine, cobalt blue, petal, vermilion, yellow lead, titanium yellow, carbon black and other inorganic pigments, quinacridone, permanent red 4R, isoindolinone, Hansa Yellow A, phthalocyanine blue, Organic pigments or dyes such as Induslen Blue RS, aniline black, metal pigments made of foil powder such as aluminum and brass, pearlescent pigments made of titanium dioxide-coated mica, basic lead carbonate foil powder, etc. Used. In addition, extender pigments (fillers) such as calcium carbonate, silica (silicon dioxide), alumina (aluminum oxide), and barium sulfate are added as necessary.
[0011]
In order to form a pattern with an ink pattern layer, a normal printing method such as gravure printing, offset printing, letterpress printing, silk screen printing, or the like can be used, but drawing may also be used. The pattern layer is formed by forming an ink composed of a resin binder and a pigment or dye into an arbitrary pattern. In addition, a transfer sheet having an ink layer formed on a releasable support sheet and an adhesive layer as necessary is prepared in advance, and the ink layer formed on the transfer sheet is pressurized or pressurized. It can also be based on a so-called transfer printing method in which a pattern layer (ink pattern layer) is formed by heating. Examples of the pattern include wood grain, stone grain, cloth grain, crest, character, figure, full face, and the like. As the 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. As the pigment or dye, the same ones as described above are used.
[0012]
The pattern formed by the metal layer is formed by vacuum deposition of a metal such as aluminum, chromium, gold, silver, or copper. Such a metal layer may be formed on the entire surface, or may be formed in a pattern (pattern shape). However, in order to form a pattern, a removal layer is formed in a desired pattern with water-soluble ink in an unnecessary part of the metal layer. According to a known method, for example, a metal is vapor-deposited on the entire surface from above, and then washed with water to remove the metal layer immediately above the removal layer together with the removal layer. Alternatively, a so-called transfer printing method can be used in which a metal layer previously formed on a transfer sheet is transferred to a surface on which a pattern layer (metal layer) is formed.
[0013]
As a method for forming the concavo-convex pattern, there are hairline processing, sandblasting, embossing, and the like, and the concavo-convex pattern having the concavo-convex shape is formed on the base sheet by these methods.
[0014]
Embossing is performed by pressing the embossed plate against the surface of the heated and softened base sheet using a hot-press type single wafer or rotary embossing machine and shaping the uneven shape of the embossed plate surface. This is a method of forming an uneven pattern. Examples of the concavo-convex pattern formed by this embossing include a wood grain conduit groove, a wood grain bark, a stone surface irregularity, a fabric surface texture, a satin texture, a grain, a hairline, or a combination thereof. The concave and convex portions of the concavo-convex pattern are filled with colored ink by a known wiping method as necessary. As the colored ink, a urethane resin, an acrylic resin, a polyester resin, or other conventional vehicle added with a pigment or a dye is selected and used, but a two-component curable adhesive and a good solvent resistance are preferable. . The wiping may be performed by any conventionally used wiping method such as a doctor blade method or a roll coating method. By these methods, colored ink is applied to the entire surface of the concavo-convex pattern, and then the ink on the convex portion is scraped off to leave the colored ink in the concave portion.
[0015]
Examples of the decorative sheet Ru used in the present invention is shown in FIG. A decorative sheet S shown in FIG. 1A is obtained by forming a pattern layer 4 on a colorless and transparent base sheet 1 by printing and laminating a surface protective sheet 7 thereon. In addition, the decorative sheet shown in FIG. 1B is formed by forming a pattern layer 4 by printing on the surface of a base material sheet 1 colored by adding a colorant 2 such as a pigment, and a surface protective sheet 7 is laminated thereon. Is. The decorative sheet S shown in FIG. 1 (c) has a pattern layer 4 formed by printing on the surface of a base sheet 1 colored by adding a colorant 2 such as a pigment, and a surface protective sheet 7 is laminated thereon. Then, the uneven | corrugated pattern which consists of the recessed part 5 is a decorative sheet by embossing. Further, the decorative sheet S shown in FIG. 1D is obtained by wiping the colorant 6 in the concave portion on the surface of the decorative sheet shown in FIG. If necessary, an overcoat layer may be provided on the surfaces of the various decorative sheets shown in FIGS. This overcoat layer (not shown) is selected from the paints used as the overcoat layer of ordinary known decorative sheets. A transparent paint is used so that the decoration process can be seen through. Typical examples of the binder (resin component) of the paint include a two-component curable urethane resin, a cellulose resin, and an acrylic resin.
[0016]
These decorative sheets S are composed of two layers of a base sheet 1 and a surface protective sheet 7 by a dry laminating method in which an adhesive such as a two-component curable urethane resin is interposed between the two layers as they are or by heat-sensitive fusion. It manufactures by laminating | stacking by a heat sealing | fusion (welding) method through the adhesive of a mold type.
[0017]
A preferred method for producing the decorative sheet S as shown in FIG. 1 (a) or 1 (b) is as follows. First, a colored polylactic acid-based resin is formed into a stretched sheet to produce a base sheet, and printing or the like is performed on the base sheet as necessary. In addition, a surface protection sheet is produced by forming a transparent polylactic acid resin into a stretched sheet. Then, as shown in FIG. 2, the adhesive 14 is applied by the roll coater 13 while the base sheet 12 is fed out from the winding 11, and the adhesive is dried as it is through the drying device 15. On the other hand, the surface protection sheet 17 is fed out from the winding 16. And it supplies between the pressure roll (pressure drum) 18 and the lamination roll (in this case metal mirror surface roll) 19 in the state which pinched | interposed the adhesive bond layer between the base material sheet 12 and the surface protection sheet 17, and both are supplied. The surface protection sheet 17 is laminated on the base sheet 12 by pressing. Immediately before being inserted between the pressure roll 18 and the laminate roll 19, preheating devices 21 and 22 such as an infrared radiation heater are provided as necessary, and the base sheet 12 and the surface protection sheet 17 are heated and softened. The decorative sheet 20 manufactured in this manner is formed by stretching the base sheet 12 and the surface protection sheet 17 and is excellent in tensile strength and elongation. Therefore, the decorative sheet 20 has suitability for processing such as V-cut processing and lapping processing. It is good. When manufacturing the decorative sheet S as shown in FIG. 1 (c) or FIG. 1 (d), the laminate roll 19 in FIG. The embossed version. In this case, heating by the preheating devices 21 and 22 is essential.
[0018]
The decorative sheet can be laminated on another adherend (backing material). The adherend is the final product, and there are cases where a decorative sheet is laminated for the surface makeup, and if necessary, the decorative sheet is applied to the back of the decorative sheet to reinforce the mechanical strength or to provide concealment. The body may be laminated. When laminating to the adherend, the adhesive layer may be omitted if the decorative sheet itself can be adhered to the adherend (by a thermal melting point or the like). If the decorative sheet itself does not adhere to the adherend, an appropriate adhesive is used.
[0019]
3 and 4 are cross-sectional views showing the decorative sheet laminated on the adherend together with the adherend. FIG. 3 shows a flat plate in which the decorative sheet S shown in FIG. 4 is laminated with an adhesive layer 9, and the one shown in FIG. 4 is a method of simultaneously laminating the decorative sheet S shown in FIG. ).
[0020]
Examples of the adherend include flat plates made of various materials (FIG. 3), plate materials such as curved plates, three-dimensional shaped articles (FIG. 4), and articles of various shapes such as sheets (or films). The materials used for any of the plate material, the three-dimensional shaped article, and the sheet (film) include wood veneer such as wood veneer, wood plywood, particle board, medium density fiberboard (MDF), iron, aluminum Metals such as copper, acrylic resin, polycarbonate resin, ethylene / vinyl acetate copolymer, ethylene vinyl acetate, polyester resin, polystyrene, polyolefin resin, ABS, phenol resin, polyvinyl chloride, cellulose resin, rubber, etc. is there. As materials exclusively used as plate materials or three-dimensional shaped articles, there are ceramics such as glass and ceramics, cements such as ALC (foamed lightweight concrete), non-cement ceramic materials such as calcium silicate and gypsum. Materials used exclusively as sheets (or films) include paper such as high-quality paper and Japanese paper, and nonwoven fabrics or woven fabrics made of fibers such as cellulose, carbon, asbestos, potassium titanate, glass, and synthetic resins.
[0021]
As a method for laminating a decorative sheet on these various adherends, for example, 1) a method of laminating a plate-like substrate by pressing with a pressure roller with an adhesive layer interposed therebetween, 2) Japanese Patent Publication No. 50-19132 As described in Japanese Patent Publication No. SHO 43-27488, etc., a decorative sheet is inserted between both male and female molds for injection molding, both molds are closed, and molten resin is injected and filled from a male gate. After that, it is cooled, and a decorative sheet is bonded and laminated on the surface of the resin molded product at the same time. So-called injection molding simultaneous laminating method, 3) described in JP-B-56-45768, JP-B-60-58014, etc. Thus, the decorative sheet is opposed to or placed on the surface of the molded product with an adhesive layer interposed therebetween, and the decorative sheet is laminated on the molded product surface by the pressure difference due to vacuum suction from the molded product side. Press lamination method, 4) Shoko As described in JP-A-61-5895, JP-B-3-2666, and the like, while supplying a decorative sheet via an adhesive layer in the major axis direction of a columnar substrate such as a cylinder or a polygonal column A so-called wrapping method in which a decorative sheet is sequentially pressure-bonded and laminated on a plurality of side surfaces constituting a columnar body by a plurality of rollers having different orientations. 5) Japanese Utility Model Publication No. 15-31122, JP As described in Japanese Patent Publication No. 48-47972, etc., a decorative sheet is first laminated on a plate-like substrate via an adhesive layer, and then a decorative sheet is provided on the surface of the plate-like substrate opposite to the decorative sheet. After cutting a groove having a V-shaped or U-shaped cross section at a depth reaching the interface between the plate and the plate-like base material, and then applying an adhesive in the groove , There is a so-called V-cut or U-cut processing method in which a box or a columnar body is formed by bending.
[0022]
In particular, among the above methods, the method of laminating the decorative sheet of the present invention on the three-dimensional object is preferably an injection molding simultaneous laminating method, a vacuum press laminating method, a lapping process method, a V-cut process method, or the like.
[0023]
【Example】
Example 1
A base sheet was prepared as follows. That is, for 100 parts by weight of a polylactic acid-based resin (weight average molecular weight 200,000) mainly composed of poly-L-lactic acid, 10 parts by weight of titanium white as a coloring pigment and 0% of benzotriazole-based ultraviolet absorber. The composition to which 5 parts by weight was added was formed into a film by extrusion molding, and then the sheet was biaxially stretched at a stretch ratio of 3 times and heat-treated at 100 ° C. to obtain an opaque colored base sheet having a thickness of 80 μm. It was.
[0024]
Next, the pattern was printed on said base material sheet. Specifically, a two-component curable urethane resin composed of hexamethylene diisocyanate and acrylic polyol is used as a binder, and an ink prepared by mixing petals, carbon black, titanium dioxide, and benzidine yellow is used as a pigment. The wood grain pattern of eyes was printed to form a pattern layer.
[0025]
On the other hand, 100 parts by weight of a polylactic acid-based resin (weight-average molecular weight 200,000) containing poly-L-lactic acid as a main component is 0.5 parts by weight of a benzotriazole-based ultraviolet absorber, and a hindered amine-based radical scavenger is 0.1%. A composition added with 5 parts by weight was formed into a sheet by extrusion forming, and the sheet was biaxially stretched at a stretch ratio of 3 times and heat-treated at 100 ° C. to be colorless and transparent having a thickness of 80 μm. The surface protective sheet was used.
[0026]
Next, the surface protective sheet and the base sheet were dry laminated and bonded and laminated via an adhesive layer (thickness 10 μm) of a two-component curable urethane resin composed of acrylic polyol and hexamethylene diisocyanate. In this case, the pattern layer of the base sheet was made to face the surface protection sheet. Finally, the top coat layer was coated with a thickness of 3 μm to produce a decorative sheet. This overcoat layer was formed using a composition in which a two-part curable urethane resin composed of hexamethylene diisocyanate and acrylic polyol was used as a binder, and 3 parts by weight of a silica pigment was added as a matting agent to 100 parts by weight of this. .
[0027]
(Example 2)
The decorative sheet produced in Example 1 was bonded to a lauan plywood having a thickness of 7 mm with an adhesive to obtain a decorative board. The used adhesive is a vinyl acetate two-component curable emulsion (isocyanate is used as a curing agent).
[0028]
(Comparative Example 1)
A decorative sheet was produced in the same manner as in Example 1 except that the base sheet and the surface protective sheet were unstretched.
[0029]
(Comparative Example 2)
The decorative sheet of Comparative Example 1 was attached to the lauan plywood in the same manner as in Example 2 to obtain a decorative board.
[0030]
(Evaluation)
(1) Weathering test An exposure test was performed by irradiating with a carbon arc vertical sunshine weatherometer for 1000 hours. The conditions were a black panel temperature of 63 ° C. and a rain cycle of 18 minutes / 120 minutes. And when the retention rate of the tensile strength after exposure was measured and the discoloration color was observed visually, the decorative sheet of Example 1 and Comparative Example 1 had a retention rate of 70% and was conspicuous in appearance. No change was seen.
[0031]
(2) Degradability The decorative sheets of Example 1 and Comparative Example 1 were embedded in the soil of Miyoshi-cho, Iruma-gun, Saitama Prefecture, left undiscovered for 6 months from April to September, and excavated. And when the external appearance was observed visually, decomposition | disassembly was advancing and the original form was not hold | maintained but the sheet | seat was fragmented. Further, the molecular weight retention rate of the recovered decorative sheet fragments measured for reference was 40%.
[0032]
(3) Formability (V cut processing)
About the decorative board of Example 2 and Comparative Example 2, the cross-section V-shaped groove (V-shaped groove) has a depth reaching the interface between the lauan plywood and the decorative sheet on the non-bonding surface side of the decorative sheet in the lauan plywood. After cutting an angle of 90 °, a vinyl acetate emulsion adhesive was applied in the groove, and the groove was folded so that the groove was closed, and processed into an L-shaped decorative board. When the folded corner of the decorative sheet was observed, the decorative plate of Example 2 was not cracked or whitened. On the other hand, in the decorative board of Comparative Example 2, cracks and whitening around the cracks were observed.
[0033]
【The invention's effect】
As described above, the decorative sheet adherend of the present invention, the decorative sheet is required weather resistance, has a molding processability, tensile that is particularly oriented substrate sheet and a surface protective sheet both strength In addition, since it is excellent in elongation and processing suitability such as V-cut processing is good, cracks and whitening do not occur in the corners where the decorative sheet is folded. Also, while you are used to the inner sweeping of buildings decorative sheet does not biodegradable deterioration in the moisture and bacteria in the air, yet decorative sheet was left in contact with the soil or in the soil was once waste disposal At that time, the base sheet is completely decomposed into water and carbon dioxide gas by the action of microorganisms in the soil and disappears, which is preferable for the global environment.
[Brief description of the drawings]
1 is a cross-sectional view showing an example of a decorative sheet Ru used in the present invention.
FIG. 2 is an explanatory view showing an example of a method for manufacturing a decorative sheet.
FIG. 3 is a cross-sectional view showing a decorative sheet laminated on an adherend together with the adherend.
FIG. 4 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 4 pattern layer 5 recess 6 colorant 7 surface protective sheet 8 adherend 9 adhesive 10 adherend 11 winding 12 base sheet 13 roll coater 14 adhesive 15 drying device 16 Winding 17 Surface protective sheet 18 Pressure roll 19 Laminating roll 20 Decorative sheet 21, 22 Preheating device

Claims (1)

Poly-L- with a weight average molecular weight of 100,000 or more is formed on a base sheet obtained by drawing a polylactic acid-based resin mainly composed of poly-L-lactic acid having a weight average molecular weight of 100,000 or more into a stretched sheet and then heat-treating it. formed by laminating a transparent surface protective sheet comprising a further heating treatment was stretched sheet of polylactic acid resin composed mainly of lactic acid, decorative sheet decorated processing to one of at least the base sheet and the surface protective sheet A decorative sheet adherend formed by laminating a decorative sheet and a plate-like base material on a surface opposite to the decorative sheet of the platy base material on which the decorative sheet is laminated via an adhesive layer After cutting a groove having a V-shaped or U-shaped cross-section at a depth reaching the position, and applying an adhesive in the groove, the plate-like base material is bent by the groove to form a box or a columnar body. A decorative sheet adherend characterized by that.

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