JP2008149732A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel decorative sheet which has required weather resistance and shaping aptitude while being spontaneously perishable simply when left abandoned. <P>SOLUTION: An image pattern 4 is printed in a decoration processing on a base sheet 1 which is made into a stretched sheet comprising a resin mix of a polylactic acid resin hard segment and a polycaprolactone polymer soft segment, a non stretched surface protection layer 7 comprising the same resin as the base sheet 1 is laminated on it, and a concavo-convex pattern is formed on the surface protection layer 7 by embossing. The resultant sheet has weather resistance and shaping aptitude required for a decorative sheet and does not deteriorate in biodegradation due to moisture or bacteria in the air while in use as an upholstery material, etc. for buildings laminated on an adherend 8; whereas its base sheet perishes completely decomposed into water and carbon dioxide by the action of microorganisms in soil, once left abandoned in contact with or berried in the soil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decorative sheet used for various decorations including interior materials.

  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 not only excellent in printing and embossing, is easy to process into a decorative sheet, but also 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), Or various decorative sheets using acrylic resin have been proposed.

  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.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to provide the weather resistance and molding processability necessary for a decorative sheet, and even if it is discarded and left as it is, it is natural. It is to provide a new decorative sheet that disappears.

  In order to achieve the above object, the decorative sheet of the present invention is a stretched base sheet made of a resin obtained by mixing a polylactic acid resin as a hard segment and a polymer of polycaprolactone as a soft segment. In addition, a decorative layer is formed, an unstretched surface protective layer made of the same resin as the base sheet is laminated thereon, and an uneven pattern is formed on the surface protective layer by embossing. .

  In addition, the decorative sheet of the present invention has a decorative layer formed on a stretched base sheet made of lactic acid as a hard segment and a copolymer of a caprolactone monomer or prepolymer as a soft segment. Further, an unstretched surface protective layer made of the same resin as that of the base sheet is laminated thereon, and an uneven pattern is formed on the surface protective layer by embossing.

  The decorative sheet of the present invention has the weather resistance and molding processability necessary for the decorative sheet, and is not biodegraded and deteriorated by moisture and bacteria in the air while being used as an interior material of a building. Once disposed and left in contact with the soil or left in the soil, the base sheet is completely decomposed into water and carbon dioxide by the action of microorganisms in the soil and disappears, which is preferable for the global environment. .

  The polylactic acid-based resin as the hard segment is produced from starch, and the polylactic acid-based resin used in the present invention is preferably one having poly-L-lactic acid as a main component. On the other hand, the soft segment serves as a modifier for imparting plasticity, and examples of the soft segment used in the present invention include polycaprolactone, and poly (ε-caprolactone) is particularly preferable.

  As a combination form of these hard segments and soft segments, there are two forms of a mixture and a copolymer. That is, the mixture is a mixture of lactic acid (polylactic acid resin) that is a homopolymer and caprolactone (polycaprolactone) that is a homopolymer. The copolymer means unpolymerized lactic acid (hereinafter also referred to as “lactic acid monomer”) or a prepolymer thereof, and unpolymerized caprolactone (hereinafter also referred to as “caprolactone monomer”). ) Or a copolymer of the prepolymer. Soft segment can be mixed or copolymerized with pure polylactic acid resin to reduce its hardness (ie, Young's modulus, elastic limit, softening temperature, etc. can be reduced, and elongation at break can be increased) Any one may be used as long as it is a compound), but what is usually preferably used is a caprolactone monomer, prepolymer, or polymer (polycaprolactone). Hereinafter, description will be given mainly by taking these as examples.

  When a poly-L-lactic acid and poly (ε-caprolactone) are used in producing a resin obtained by mixing a polylactic acid-based resin and a polymer serving as a soft segment, the poly-L-lactic acid has a weight average molecular weight. Those having 100,000 or more, preferably 200,000 or more are used, and poly (ε-caprolactone) having a weight average molecular weight of 1 to 100,000 is used. The mixing ratio of the two is polylactic acid resin / polymer to be a soft segment = 1/9 to 9/1 (polymerization ratio).

  In the case of using a L-lactic acid monomer and ε-caprolactone in producing a copolymer of a lactic acid monomer or a prepolymer thereof and a monomer that becomes a soft segment or a prepolymer thereof, A monomer or prepolymer is used, and ε-caprolactone also uses the monomer or prepolymer. The copolymerization ratio of the two is lactic acid monomer or prepolymer / soft segment monomer or prepolymer = 1/9 to 9/1 (input polymerization ratio). The molecular weight of the copolymer is 100,000 or more, preferably 200,000 or more.

  If necessary, various additives such as an ultraviolet absorber, a light stabilizer, an antifungal agent, and a flame retardant are added to these resins. Further, a biodegradable filler such as paper powder or wood powder may be mixed.

  Both UV absorbers and light stabilizers are added to provide weather resistance (light) resistance to the base sheet (decorative sheet). Either of them may be used alone, but usually both are used in combination. To do. 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. Further, 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 used is a stretched sheet. 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 base sheet is easily plastically deformed and has good moldability. However, a stretched base sheet has high transparency, increases elasticity, and improves tensile strength and elongation. Furthermore, it is desirable to impart heat resistance and heat shrinkage resistance by heat treatment (annealing) at about 80 to 120 ° C. Moreover, the thickness of the base material sheet used by this invention is about 25-200 micrometers.

  The base sheet is subjected to a desired decoration process. 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. In addition, when using as a decorative sheet bonded to the back surface of the adherend as a backing sheet like a backing sheet, there is no need for decoration treatment.

  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, dials, 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.

  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.

  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.

  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.

  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.

  As a form of the decorative sheet, a single layer composed of only a base sheet as shown in FIG. 1, a double layer composed of a base sheet and a surface protective layer as shown in FIG. 2 (c) and 2 (d) are the decorative sheets of the present invention.

  A decorative sheet S shown in FIG. 1A is obtained by adding a colorant 2 such as a pigment to the base sheet 1 and coloring, and the decorative sheet S of FIG. 3 is provided, and the pattern layer 4 (entire solid or partial pattern) is formed thereon by printing. Moreover, the decorative sheet S of FIG.1 (c) forms the uneven | corrugated pattern which consists of the recessed part 5 in the surface of the base material sheet 1, and the decorative sheet S of FIG.1 (d) has the coloring agent 6 in the recessed part of the surface. It is filled with wiping.

  A decorative sheet S shown in FIG. 2A is obtained by forming a picture layer 4 on a base sheet 1 by printing and laminating a surface protective layer 7 thereon. The decorative sheet shown in FIG. 2 (b) has a pattern layer 4 formed 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 layer 7 is laminated thereon. Is. As the surface protective layer 7, it is preferable in terms of biodegradability to use the same polylactic acid resin as that of the base sheet. 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, an electron beam or ultraviolet curable acrylate resin, an epoxy resin, or the like can be given. The surface protective layer 7 is formed by pasting sheets formed in advance or by applying a resin.

  The decorative sheet S shown in FIG. 2 (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 layer 7 is laminated thereon. After that, a concavo-convex pattern composed of the concave portions 5 is formed by embossing. Further, the decorative sheet S shown in FIG. 2 (d) is obtained by wiping the colorant 6 into the concave portion of the surface of the decorative sheet shown in FIG. 2 (c) by wiping. In the case of a decorative sheet having a two-layer structure as shown in FIGS. 2A to 2D, the base sheet 1 on the back side is the one stretched under the above conditions, and the surface protective layer 7 is used. It is preferable to use an unstretched one made of a polylactic acid resin.

  A preferred method for producing the decorative sheet S as shown in FIG. 2 (c) is as follows. First, a base sheet 1 is manufactured by making a polylactic acid resin as described above into a stretched sheet, and printing or primer coating is performed on the base sheet 1 as necessary. Then, as shown in FIG. 3, while the base sheet 1 is passed between the pressure roll (impression cylinder) 11 and the cooling roll (embossing plate cylinder) 12, the polylactic acid-based resin as described above is used as the surface protective layer 7. By extruding from the die 13 in a molten state, the surface protective layer 7 is laminated on the base sheet 1 and at the same time, an uneven pattern is formed on the surface protective layer 7 by the action of the cooling roll 12 also serving as an embossed plate. Since the decorative sheet produced in this way is not stretched, the surface protective layer 7 is easy to be embossed by plastic deformation, and the base sheet 1 is stretched and is excellent in tensile strength and elongation. Good processing, such as cutting and lapping. In other words, this type of polylactic acid-based resin decorative sheet has both embossing suitability (good irregular shape shaping) and tensile strength and elongation sufficient for bending such as V-cut processing. Can be made.

  The decorative sheet of the present invention 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.

  4 and 5 are sectional views showing the decorative sheet laminated on the adherend together with the adherend, and FIG. 4 shows a flat plate in which the decorative sheet S shown in FIG. 5 is laminated via an adhesive layer 9, and the one shown in FIG. 5 has a decorative sheet S formed by applying the pattern layer 4 by printing on the base sheet 1 on the surface of the uneven three-dimensional object as the adherend 10. It is laminated by a simultaneous molding laminating method (described later).

  Examples of the adherend include flat plates made of various materials (FIG. 4), plate materials such as curved plates, three-dimensional shaped articles (FIG. 5), 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 And other metals such as acrylic resin, polycarbonate resin, ethylene / vinyl acetate copolymer, ethylene vinyl acetate, polyester resin, polystyrene, polyolefin resin, ABS, phenol resin, polyvinyl chloride, cellulose resin, and rubber. 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. As materials exclusively used as sheets (or films), there are paper such as high-quality paper and Japanese paper, and non-woven fabrics or woven fabrics made of fibers such as carbon, asbestos, potassium titanate, glass, and synthetic resins.

  As a method for laminating the decorative sheet on these various adherends, for example, 1) a method of laminating by pressing with a pressure roller on a plate-like substrate with an adhesive layer interposed therebetween, and 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. Thereafter, it is cooled and a decorative sheet is adhered and laminated on the surface of the resin molded product at the same time, so-called injection molding simultaneous laminating method, and 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 6 As described in Japanese Patent No. 5895, Japanese Patent Publication No. 3-2666, etc., while supplying a decorative sheet via an adhesive layer in the long axis direction of a columnar substrate such as a cylinder or a polygonal column, A so-called lapping process 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 of different orientations. 5) Japanese Utility Model Publication No. 15-31122, JP As described in Japanese Patent Publication No. 48-47972 and the like, first, a decorative sheet is laminated on a plate-like base material via an adhesive layer, and then, on the surface of the plate-like base material opposite to the decorative sheet, Cutting a groove having a V-shaped or U-shaped cross section that reaches the interface with the plate-like substrate, and then applying an adhesive in the groove, then bending the groove to form a box or columnar body. There are so-called V-cut or U-cut processing methods.

  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.

  The decorative sheet of the present invention is laminated on various adherends and subjected to a predetermined molding process, etc., and used for various applications. For example, interior decorations for buildings such as walls, ceilings, floors, doors, window frames, door frames, surface decorations for fittings such as handrails, furniture such as bags, surface decorations such as cabinets for light electrical / OA equipment, automobiles, trains, etc. These include vehicle interiors, aircraft and ship interiors, and window glass makeup.

(Example 1)
A base sheet was prepared as follows. That is, a resin in which 70% by weight of a poly-L-lactic acid-based resin having a weight average molecular weight of 200,000 and 30% by weight of poly (ε-caprolactone) having a weight average molecular weight of 30,000 is produced, and is used for 100 parts by weight of the resin. Then, 10 parts by weight of titanium white as a coloring pigment and 0.5 parts by weight of a benzotriazole-based ultraviolet absorber are added, the composition is biaxially stretched at a stretch ratio of 3 times, and heat-treated at 100 ° C. to obtain a thickness. A film was formed to 80 μm.

  Next, the pattern was printed on said base material sheet. Specifically, a two-component curable polyurethane resin composed of hexamethylene diisocyanate and acrylic polyol is used as a binder, and an ink comprising a mixture of petrol, 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.

  Subsequently, with respect to 100 parts by weight of the same resin as described above obtained by mixing 70% by weight of a poly-L-lactic acid resin having a weight average molecular weight of 200,000 and 30% by weight of poly (ε-caprolactone) having a weight average molecular weight of 30,000. Then, a composition containing 0.5 parts by weight of a benzotriazole-based ultraviolet absorber and 0.5 parts by weight of a hindered amine-based radical scavenger was used, and this composition was melted from a T die as shown in FIG. Extruding and laminating on the printing surface of the base material sheet to a thickness of 60 μm, and at the same time embossing the groove irregularities on the surface of the brazing material with a cooling roll also serving as an embossing plate. Next, sepia-colored ink (the binder is an acrylic resin and the pigment is a valve) is filled in the conduit groove by a wiping method. 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. .

(Example 2)
During the ring-opening polymerization of lactide, ε-caprolactone was copolymerized to produce a copolymer having a copolymerization ratio of L-lactic acid / ε-caprolactone = 70/30 (input weight ratio). The weight average molecular weight of the copolymer was 200,000. A decorative sheet was produced in the same manner as in Example except that this resin was used in place of the mixed resin of poly-L-lactic acid resin and poly (ε-caprolactone).

(Evaluation)
1) Workability Each decorative sheet produced in Examples 1 and 2 was bonded to a lauan plywood having a thickness of 2.5 mm with an adhesive to form a decorative board. The used adhesive is a vinyl acetate two-component curable emulsion (isocyanate is used as a curing agent). Then, a groove having a V-shaped cross section is carved to the boundary surface between the plywood and the decorative sheet on the back surface of each decorative board obtained, and a vinyl acetate adhesive is applied to the groove to fold the plywood to 90 degrees together with the sheet. So-called V-cut processing was performed. The atmospheric temperature during processing was 20 ° C. In the bent portion, the decorative sheet was not torn, cracked, whitened or the like.

2) Weather resistance 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 sheets of Examples 1 and 2 had a tensile strength retention rate of 70%, and a noticeable change in appearance. Was not seen.

3) Degradability Each decorative sheet of Examples 1 and 2 was embedded in the soil of Miyoshi-cho, Iruma-gun, Saitama Prefecture, and left for 6 months from April to September before excavation. 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%.

It is sectional drawing which shows the example of the decorative sheet which concerns on this invention. It is sectional drawing which shows the other example of the decorative sheet which concerns on this invention. It is explanatory drawing of the manufacturing method of the decorative sheet which gave the uneven | corrugated pattern to the surface protective layer. It is sectional drawing which shows the decorative sheet laminated | stacked on the to-be-adhered body with the to-be-adhered body. It is sectional drawing which shows the decorative sheet laminated | stacked on the to-be-adhered body with the to-be-adhered body.

Explanation of symbols

DESCRIPTION OF SYMBOLS S Cosmetic sheet 1 Base material sheet 2 Colorant 3 Easy-adhesion layer 4 Picture layer 5 Recessed part 6 Colorant 7 Surface protective layer 8 Adhering body 9 Adhesive 10 Adhering body 11 Pressure roll 12 Cooling roll 13 T die

Claims (2)

  A polylactic acid resin is used as a hard segment, and a decorative layer is formed on a stretched base sheet made of a resin obtained by mixing a polymer of polycaprolactone that is a soft segment. A decorative sheet comprising a non-stretched surface protective layer made of the same resin, and an uneven pattern formed on the surface protective layer by embossing.   A decorative layer is formed on a stretched base sheet made of a copolymer of a lactic acid hard segment and a caprolactone monomer or prepolymer, which is a soft segment, and the same as the base sheet. A decorative sheet comprising a non-stretched surface protective layer made of a resin and an uneven pattern formed on the surface protective layer by embossing.

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