JP2009178880A - Polylactic acid-based single layer decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet composed of a raw material derived from plants, which can endure three-dimensional molding, such as lapping processing and vacuum forming with a base material having a three-dimensional shape, as well as lamination to a planar base material and which is superior also in surface physical properties such as scratch resistance. <P>SOLUTION: In the decorative sheet the thermoplastic resin sheet is a biaxially oriented sheet of a material having a polylactic acid resin as a major agent and having an oily plasticizer added in an amount of 0.1-10 pts.wt. based on 100 pts.wt. of the polylactic acid resin. The thermoplastic resin sheet has a glass transition point of 50-90°C, a tensile elongation at break (according to JIS K6781) of 2.0-3.5 GP and a tensile elongation at break of 100-200%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a decorative sheet for use in interior and exterior materials of buildings such as houses, building materials such as construction materials and fittings, furniture fixtures, housing equipment, home appliances, and other surface makeup. More specifically, it has excellent dimensional stability and surface strength, and is also suitable for three-dimensional molding applications such as wrapping laminate or vacuum molding laminate. Preferably, plant-derived plastic polylactic acid resin is the main raw material, and toxic gas is also used during incineration. This is a cosmetic sheet that does not occur and is friendly to the global environment and the human body.

  As such a resin-based decorative sheet, a decorative sheet having a single-layer configuration in which a pattern is printed on the front surface side or the back surface side of the thermoplastic resin base sheet, and a thermoplastic resin base sheet on the back surface side of the pattern layer. There is a decorative sheet having a multilayer structure sandwiched between the transparent resin layer on the surface side. The former has the advantage that it can be manufactured easily and cheaply because of its simple structure, while the latter is somewhat disadvantageous from the manufacturing and price points, but the pattern is protected from both the front and back sides, so the wear resistance of the pattern It combines surface properties such as solvent resistance and weather resistance, and resistance to the adhesive used when adhering to the substrate to be adhered, and also from the design side, it is highly concealed by coloring the base sheet and transparent There are many advantages in terms of performance, such as being able to achieve both high design by embossing the resin layer. Due to this relationship, both are properly used according to the performance and price required by the application.

  Conventionally, as a thermoplastic resin used for this type of decorative sheet, vinyl chloride resin, polyolefin resin, acrylic copolymer resin, etc. are used as a base sheet of the decorative sheet or a transparent resin layer on the surface of the base sheet. Is done. For example, as a base sheet of a decorative sheet, paper or a thermoplastic resin sheet is used, and a printed sheet obtained by printing on the sheet is used as it is, or the transparent resin layer described above as a surface protective layer and / or a design expression layer. Are used, and are used by being bonded to the surface of a wood-based substrate such as wood plywood, wood fiber board, particle board or the like. In particular, high-strength resin materials having excellent surface strength such as vinyl chloride resin and polyethylene terephthalate resin have been used for floor materials and edge materials that require surface strength.

  Conventionally, polyvinyl chloride resin, which is inexpensive and excellent in processability and physical properties, has been most frequently used as a constituent material for the base sheet and transparent resin layer of the various resin-based decorative sheets described above. In response to the growing social interest in the problem, decorative sheets using resins other than polyvinyl chloride resins that have little adverse effects on the environment, such as polyolefin-based thermoplastic resins, have been developed and proposed.

  A decorative sheet using the above-mentioned polyolefin-based thermoplastic resin has been conventionally used in terms of flexibility and whitening resistance required for secondary processing such as laminating of a decorative sheet to a substrate to be adhered and V-cut processing. Since the performance almost equivalent to that of polyvinyl chloride resin can be obtained relatively easily, it is currently considered most promising among various alternative materials for polyvinyl chloride resin. On the other hand, however, the thermoplastic polyolefin-based thermoplastic resin has a lower surface hardness than the polyvinyl chloride resin having the same flexibility, and tends to have poor scratch resistance on the surface.

  On the other hand, various decorative sheets using a polyester-based thermoplastic resin have been proposed. Polyethylene terephthalate resin, the most common polyester-based thermoplastic resin, has a tensile modulus of around 4 GPa, and is too soft for decorative sheets, so it has poor processability, so it can be softened by adding various copolymer components. For example, it is made of a copolyester having a difference between the cold crystallization temperature and the glass transition temperature of 60 ° C. or less and has a quasicrystal melting peak temperature not lower than the cold crystallization temperature and not higher than the melting point. A decorative sheet using a flexible polyester film having an elastic modulus of 1 to 500 MPa has been proposed (see Patent Document 1, Patent Document 2 and Patent Document 3).

  However, although the above-mentioned flexible polyester film has solved the problems such as whitening and breakage caused by bending such as V-cut, it has low surface hardness due to its flexibility and is inferior in scratch resistance. In addition, the base material to which the decorative sheet is attached is not necessarily a flat plate, and base materials having various three-dimensional shapes are increasing in various uses such as for bathroom wall surfaces. When affixing to a shaped substrate by a lapping method, a vacuum forming method, or the like, the above-described flexible polyester film is too soft and has a problem that wrinkles, scratches and the like are likely to occur.

  In recent years, life-cycle assessment (hereinafter referred to as LCA) has begun to be introduced, and how much resources and energy are used to manufacture, use, and dispose of products, quantification of various pollutants, and to the environment Has been evaluated (Non-Patent Document 1). Polylactic acid resin has attracted a great deal of attention because it is one of the most mass-produced biomass materials on the earth and is a biodegradable polymer. Polylactic acid resin is a biomass material that uses starch produced by photosynthesis from carbon dioxide gas and water as a raw material, and it hydrolyzes naturally in soil and water, and then becomes a biodegradable resin that is harmlessly decomposed by microorganisms. But there is. Furthermore, the amount of heat generated by combustion is small, and the carbon dioxide generated during combustion is carbon dioxide in the atmosphere that was originally absorbed when photosynthesising starch, which is the raw material for polylactic acid resin, and is the most promising biodegradation that is friendly to the environment. It is said to be an environmentally friendly biomass resin, and it seems to reduce the environmental burden.

  Polylactic acid resin is also known as a biodegradable resin, but laminated sheets made of biodegradable resins have excellent surface strength, but have poor heat resistance and poor durability (biodegradability) Until now, it has not been put to practical use as a decorative sheet because of its poor chemical resistance. On the other hand, a decorative member in which a conventional decorative sheet is bonded to a wooden substrate is difficult to separate the decorative sheet and the wooden substrate at the time of disposal, and the material of the surface decorative sheet cannot be distinguished. Due to problems, it is difficult to recycle raw materials, and incineration processing is also difficult due to the problem of generation of harmful gases, and there is a current problem that a disposal method such as landfill processing must be taken. In addition, when carrying out the landfill process, it is necessary to design the material so that no harmful substances are contained in the biodegradable decorative sheet. The transition from a molecular ordered state to a disordered state of a biodegradable decorative sheet is a natural idea (Non-patent Document 3). This is because harmful substances also diffuse into the natural world at this time.

In this way, environmental awareness and crude oil prices in recent years ($ 89.00 / barrel (1 barrel: 158.98772949 liters, New York Mercantile Exchange (NYMEX), October 17, 2007)) Examples of using a polylactic acid film, which has begun to spread as a non-petroleum polymer, as a decorative sheet can be found in Patent Documents 4 and 5. However, these documents do not have a specific description regarding the film, and cutting processing is performed. It has been desired to disclose a film suitable for processing such as printing, laminating and the like.

  Examples of methods for reducing the breaking elongation and breaking strength of biaxially stretched polyester films are found in Patent Documents 6 and 7. However, these examples all relate to a film intended as a packaging material, there is no specific description for a decorative sheet, and it cannot be said to be sufficient to solve the problems of the present invention.

In addition, a decorative sheet using a structurally simple single-layer plant-derived material as a decorative sheet base material has also been known. It was difficult to obtain a sheet (Patent Documents 8, 9, and 10).
JP-A-6-166159 Japanese Patent Laid-Open No. 7-017005 JP-A-7-137205 JP-A-11-129426 Japanese Patent Laid-Open No. 11-227147 Japanese Patent Laid-Open No. 5-104618 JP 2001-191407 A Japanese Patent Laid-Open No. 08-295755 Japanese Patent Laid-Open No. 11-207916 Japanese Patent Laid-Open No. 11-227147 Koichi Narita et al., LCA in polyethylene beer case recycling, Proceedings of the 1st Annual Meeting of the LCA Society of Japan, p124-p125, December 2005 (Web version) Nikkei morning edition article, Nikkei Inc., October 18, 2007, No. 43734, 14th edition, 1 page Akira Harashima, Thermodynamics / Statistical Mechanics, 25th revised edition, February 25, 2000, p. 32

  The present invention has been made in order to solve the above-described problems in the prior art, and the object of the present invention is not only to laminate on a planar substrate but also to a three-dimensional substrate. An object of the present invention is to provide a decorative sheet made of a plant-derived raw material that can withstand three-dimensional molding such as lapping and vacuum forming, and has excellent surface properties such as scratch resistance.

The present invention solves this problem, that is, the invention according to claim 1 is a single-layer decorative sheet provided with a pattern layer on a thermoplastic resin sheet,
The thermoplastic resin sheet is a biaxially stretched sheet obtained by adding 0.1 to 10 parts by weight of an oily plasticizer to 100 parts by weight of a polylactic acid resin with a polylactic acid resin as a main ingredient, The glass transition point of the thermoplastic resin sheet is 50 to 90 ° C., the tensile breaking elongation (conforming to JIS K6781) is 2.0 to 3.5 GP, and the tensile breaking elongation is 100 to 200%. This is a polylactic acid single-layer decorative sheet.

  The invention according to claim 2 is the polylactic acid single-layer decorative sheet according to claim 1, wherein the oily plasticizer is a plant-derived oily plasticizer.

  According to the invention of claim 1, by making the thermoplastic resin of a single-layer decorative sheet biaxially stretched by adding 0.1 to 10 parts by weight of an oily plasticizer with a polylactic acid resin as a main ingredient, By adjusting the glass transition point of the sheet to 50 to 90 ° C., the tensile breaking elongation (conforming to JIS K6781) to 2.0 to 3.5 GP, and the tensile breaking elongation to a range of 100 to 200%, It can withstand three-dimensional molding such as lapping to a three-dimensional substrate and vacuum molding as well as laminating to a shaped substrate, and also has excellent surface properties such as scratch resistance It becomes possible to provide a single-layer decorative sheet composed of raw materials.

  Further, according to the invention described in claim 2, it is possible to further increase the plant origin of the polylactic acid-based single-layer decorative sheet of the present invention by making the oily plasticizer also derived from the plant.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a cross-sectional structure of an embodiment of the polylactic acid single-layer decorative sheet of the present invention. The pattern layer 2 may be provided on the back surface of the thermoplastic resin sheet 1 (transparent), the concealing layer 3 may be provided as appropriate, and the gloss adjusting layer 4 and the conduit pattern layer 5 may be provided on the front side. You may provide the primer layer 6 in the outermost surface as needed.

  FIG. 2 shows a cross-sectional structure of another embodiment of the polylactic acid single-layer decorative sheet of the present invention. The pattern layer 2 may be provided on the surface of the thermoplastic resin sheet 1 (colored), and the gloss adjusting layer 4 and the conduit pattern layer 5 may be appropriately provided thereon. You may provide the primer layer 6 in the outermost surface as needed.

  The polylactic acid single-layer decorative sheet of the present invention is bonded to a woody base material using a known one-component or two-component aqueous emulsion adhesive, one-component moisture-curable urethane resin-based hot melt adhesive, or the like. It becomes a cosmetic material. (Not shown)

  As the thermoplastic resin sheet 1 in the present invention, 2 is one comprising a polylactic acid resin as a main component and 0.1 to 10 parts by weight of an oily plasticizer added to 100 parts by weight of the polylactic acid resin. An axially stretched sheet having a glass transition point of 50 to 90 ° C., a tensile breaking elongation (conforming to JIS K6781) of 2.0 to 3.5 GP, and a tensile breaking elongation of 100 to 200%. The adjusted one is used. The tensile modulus and tensile breaking elongation are values measured according to JIS K6781.

  The reason why the tensile elongation at break is limited to the above numerical range is that sufficient three-dimensional formability at a heating temperature (about 60 to 90 ° C.) in three-dimensional forming such as ordinary vacuum forming is obtained, and there is little residual internal stress. As well as being flexible, it has moderate waist and surface hardness, so that it does not cause wrinkles or drawdown during three-dimensional molding, and the surface properties such as scratch resistance of the surface are of a sufficient level as a decorative sheet This is because If the tensile elastic modulus is less than 2 GPa, the resin is too soft and the surface is not sufficiently scratch-resistant, causing wrinkles and scratches during laminating, and draw-down during thermoforming. If it exceeds 5 GPa, the flexibility of the resin is inadequate, resulting in poor processability, causing molding defects, residual internal stress, cracking, whitening, and the like. Also, if the tensile elongation at break is less than 100%, it will cause the workability such as wrinkles during laminating to be remarkably lowered. On the other hand, if it exceeds 200%, the warp and distortion of the laminated decorative board will be caused by its high tensile elastic modulus. It will cause imitation.

  The thermoplastic resin sheet 1 may be colored or transparent. In the case of transparency, the pattern layer 2 and the hiding layer 3 may be provided on the back side of the thermoplastic resin sheet 1. On the other hand, when colored, the pattern layer 2 and the hiding layer are provided on the surface side of the thermoplastic resin sheet 1.

  As a resin material used for the thermoplastic resin sheet 1, a polylactic acid resin is used alone or a mixture with a polysuccinate resin or other resins is used as a main agent. Biomass materials and biodegradable resins that are mixed to improve the heat resistance of polylactic acid resins include polyhydroxybutyrate, polybutylene succinate, polybutylene succinate, polycaprolactone, cellulose acetate, polyester An amide type, a vinyl acetate type, or a starch type can be appropriately selected, and a single type or a mixture of plural types may be used.

  By making the thermoplastic resin sheet 1 into a biaxially stretched sheet, the surface orientation and thermal dimensional stability are further improved by the resin orientation, and the tensile elastic modulus is increased, resulting in a state of processing and a decorative board However, a single-layer decorative sheet having excellent dimensional stability can be obtained.

  In addition, the thermoplastic resin sheet 1 may include, for example, an antioxidant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a plasticizer, a lubricant, an antistatic agent, a flame retardant, depending on the intended use of the decorative sheet. In addition, one or more conventionally known various additives such as a filler, a hydrolysis inhibitor, and a nucleating agent may be added.

  Examples of antioxidants include phenols, sulfurs, phosphoruss, etc., ultraviolet absorbers such as benzophenones, benzotriazoles, salicylates, cyanoacrylates, formamidines, oxanilides, etc. Hindered amines, nickel complexes, etc., heat stabilizers such as hindered phenols, sulfurs, hydrazines, etc., plasticizers depending on the type of resin, but phthalates, phosphates, fatty acids, etc. Type, aliphatic dibasic acid ester type, oxybenzoic acid ester type, epoxy type, polyester type, etc., as the lubricant, for example, fatty acid ester type, fatty acid type, metal soap type, fatty acid amide type, higher alcohol type, paraffin type, etc. Antistatic agents include, for example, cationic, anionic, and nonio Examples of flame retardants such as bromine, phosphorus, chlorine, nitrogen, aluminum, antimony, magnesium, boron, and zirconium, and fillers such as calcium carbonate, talc, It can be used in one or a mixture of two or more selected from wax, kaolin and the like.

  There is no restriction | limiting in particular in the thickness of the thermoplastic resin sheet 1, It can set equivalent to the case of the conventional common single layer decorative sheet. Specifically, it is often in the range of about 50 to 300 μm.

  0.1 to 10 parts by weight of an oily plasticizer is added to the thermoplastic resin sheet 1 of the present invention. As the plasticizer, commonly known petroleum-derived diisononyl phthalate (DINP), di-2-ethylhexyl phthalate, and the like can be used. In the present invention, a plant-derived resin is desirable. For example, among fats and oils composed of trihydric alcohol (glycerin) and fatty acid esters, liquid, solid saturated and unsaturated fatty oils are desirable at normal temperature 20 ° C. ± 15 ° C. (JIS Z8703-1983). For example, epoxidized soybean oil, saturated glycerin butyrate, glycerin stearate. For unsaturation, glycerin oleate, glycerin linoleate, etc. can be used.

  The pattern layer 2 is provided for the purpose of imparting the desired decorative design of the desired decorative sheet to the target decorative sheet, and the type of the pattern is not particularly limited. For example, the grain pattern, the stone pattern, Various patterns similar to the case of a conventional decorative sheet, such as an abstract pattern and a solid plain color, can be employed. There is no particular limitation on the constituent material and the forming method of the pattern layer 2, and for example, a colorant such as an organic or inorganic dye or pigment is dissolved or dispersed in an appropriate solvent together with an appropriate binder resin. Printing ink or a coating agent or the like can be provided by printing or coating by an appropriate printing method or coating method.

  Examples of the colorant include inorganic pigments such as carbon black, titanium white, zinc white, dial, bitumen, cadmium red, azo pigments, lake pigments, anthraquinone pigments, phthalocyanine pigments, isoindolinone pigments, dioxazine pigments, and the like. Metallic pigments such as organic pigments, gold powder, silver powder, copper powder, aluminum powder, bronze powder, pearl luster pigments such as fish scale powder, basic lead carbonate, bismuth oxide oxide, titanium oxide-coated mica, fluorescent pigments, nocturnal pigments, etc. Alternatively, a mixture of two or more selected from these can be used.

  Examples of the binder resin include acrylic resins, styrene resins, polyester resins, urethane resins, polyvinyl resins, alkyd resins, petroleum resins, ketone resins, epoxy resins, and melamine resins. , Various synthetic resins such as fluorine-based resins, silicone-based resins, fiber derivatives, and rubber-based resins, or a mixture or copolymer of two or more thereof can be used.

  Examples of the solvent include petroleum organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, methylcyclohexane, ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyacetate. Ester-based organic solvents such as ethyl, alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol, and ketone-based organics such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone Solvents, ether-based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; salts such as dichloromethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene It can be used various organic solvents such systems an organic solvent, an inorganic solvent such as water, or two or more mixed solvents thereof.

  In addition, various additives such as extender pigments, plasticizers, dispersants, surfactants, tackifiers, adhesion assistants, desiccants, stabilizers, curing agents, curing accelerators, or curing retarders as necessary. Can also be added as appropriate.

  The method for forming the pattern layer 2 is not particularly limited, and various conventionally known printing methods such as a gravure printing method, an offset printing method, a screen printing method, a flexographic printing method, an electrostatic printing method, and an inkjet printing method are used. be able to. In addition, for example, in the case of a solid surface, in addition to the above-described various printing methods, for example, roll coating method, knife coating method, air knife coating method, die coating method, lip coating method, comma coating method, kiss coating method, flow coating method Various coating methods such as a dip coating method can also be used. In addition, for example, the hand-drawing method, the ink-sinking method, the photographic method, the laser beam or electron beam drawing method, the partial vapor deposition method of metal or the like, the etching method, etc., or a combination of these methods can of course be performed.

  Further, the gloss adjusting layer 4 can be provided on the surface for the purpose of imparting more excellent surface properties to the surface of the single-layer decorative sheet. As the constituent material of the gloss adjusting layer 4 and the conduit pattern layer 5, any one selected from various known top coat agents conventionally used as the constituent material of the gloss adjusting layer 4 of the decorative sheet is used. can do. In general, it is necessary to have at least transparency that allows the base to be seen through, and it has surface properties such as abrasion resistance, scratch resistance, solvent resistance, and contamination resistance required for decorative sheet applications. In order to achieve this, it is preferable to use a material mainly composed of a curable resin. However, in the case of three-dimensional molding, it is necessary to consider flexibility in order to follow the elongation of the decorative sheet.

  Specific examples of the constituent material of the gloss adjusting layer 4 include heat such as melamine resin, phenol resin, urea resin, epoxy resin, aminoalkyd resin, urethane resin, polyester resin, and silicone resin. A curable resin, an ionizing radiation curable resin such as an acrylic resin, or the like can be preferably used. If necessary, various additives such as a gloss adjusting agent, a lubricant, an antistatic agent, an anti-condensation agent, an antibacterial agent and an antifungal agent can be appropriately added. Further, the gloss adjusting layer 4 is composed of two or more layers having different glosses, and one or more of them are provided in a pattern to obtain a decorative sheet having a material feeling and a visual three-dimensional effect due to a change in surface gloss. You can also.

  The method for forming the gloss adjusting layer 4 is not particularly limited. For example, a gravure coating method, a roll coating method, a dip coating method, an air knife coating method, a knife coating method, a comma coating method, a die coating method, a lip coating method, a kiss coating method, Any conventionally known coating method such as rod coating method, spray coating method, flow coating method and the like can be appropriately applied.

  When the adhesion between the thermoplastic resin sheet 1 and the gloss adjusting layer 4 is insufficient, the surface of the thermoplastic resin sheet 1 is subjected to, for example, corona treatment or ozone treatment prior to the formation of the gloss adjusting layer 4. By performing surface treatment such as plasma treatment, ionizing radiation treatment, dichromic acid treatment, anchor or primer treatment, the adhesion between the thermoplastic resin sheet 1 and the gloss adjusting layer 4 can be improved.

  As already described, the polylactic acid resin-based single-layer decorative sheet of the present invention is similar to the conventional decorative sheet, for example, a woody base material such as plywood or particle board, or an inorganic material such as calcium silicate board or wood cement board. It is used by sticking to the surface of various base materials such as plastic base materials and synthetic resin base materials such as FRP (fiber reinforced plastic). An appropriate adhesive such as vinyl is used, but depending on the type of resin constituting the thermoplastic resin sheet 1, the adhesiveness with the general-purpose laminating adhesive may be insufficient. In preparation for such a case, it is preferable to provide a primer layer 6 made of a resin excellent in adhesiveness with the general-purpose adhesive described above on the back surface of the thermoplastic resin sheet 1.

  Various primer agents such as urethane, acrylic, ethylene-vinyl acetate copolymer system, vinyl chloride-vinyl acetate copolymer system are known as the primer layer 6, and among these, the thermoplastic resin sheet 1 is used. Select and use the one that matches. In addition, when powder, such as a silica, an alumina, a calcium carbonate, barium sulfate, is added to the primer layer 6, the blocking at the time of winding-up preservation | save of a decorative sheet can be prevented by roughening the surface of the primer layer 6. In addition, the adhesiveness with the laminating adhesive due to the anchoring effect can be improved.

  The polylactic acid resin-based single-layer decorative sheet of the present invention is not only excellent in three-dimensional moldability and scratch resistance on the surface due to the configuration as described above, but also a decorative sheet using various conventional polyester-based thermoplastic resins. It has many advantages in common. For example, in the case of using a transparent polyester-based thermoplastic resin, the excellent transparency unique to the polyester-based thermoplastic resin makes it easy to create a decorative sheet with excellent pattern sharpness and high surface gloss. Obtainable.

8 parts by weight of epoxidized soybean oil as a plant-derived oily plasticizer is added to 100 parts by weight of the polylactic acid resin, biaxially stretched, the glass transition point is 58 ° C., the tensile modulus is 2.1 GPa, A transparent thermoplastic resin sheet 1 having a tensile elongation at break of 115% and a thickness of 100 μm was obtained.
On this back side, a grain pattern was printed by gravure printing, and after providing the pattern layer 2, an ink layer as a concealing layer 3 was further provided. Further, coating was performed using a two-component urethane resin as a primer layer 6 so that the coating amount after drying was 2 g / m 2.
Gravure coating on the surface side of the transparent thermoplastic resin sheet 1 with a gloss adjusting agent “UC Clear Dainippon Ink and Chemicals Co., Ltd.” with UV absorber and light stabilizer added so that the thickness after drying and curing is 9 μm. Was applied to form a gloss adjusting layer 4, and a conduit pattern layer 5 was provided thereon by gravure printing to obtain a polylactic acid-based single-layer decorative sheet of the present invention.

A colored thermoplastic resin sheet 1 was obtained in the same manner as in Example 1 except that 10 parts by weight of a titanium oxide colorant was added to 100 parts by weight of the polylactic acid resin.
On this front side, a wood grain pattern is printed by gravure printing, a pattern layer 2 is provided, and a gloss adjusting agent “UC Clear, manufactured by Dainippon Ink and Chemicals, Inc.” with an ultraviolet absorber and a light stabilizer added to the surface side. Is coated with a gravure coating so that the thickness after drying and curing becomes 9 μm to form a gloss adjusting layer 4, and further a conduit pattern layer 5 is provided thereon by gravure printing, and the polylactic acid based single layer decorative sheet of the present invention Got.

<Comparative Example 1>
A polylactic acid single-layer decorative sheet was obtained in the same manner as in Example 1 except that no oily plasticizer was added.

<Comparative example 2>
A polylactic acid single-layer decorative sheet was obtained in the same manner as in Example 1 except that 20 parts by weight of an oily plasticizer was added to 100 parts by weight of the polylactic acid resin.

<Lapping workability>
Adhesion to a MDF substrate with a commercially available wrapping machine and a one-part moisture-curing polyurethane resin hot melt adhesive, and adhesion (put in an oven at 60 ° C. for 1 hour. The peel length was measured by hanging the The evaluation criteria were as follows: ○: Can not be peeled off by hand, ×: Can be peeled off by hand.

<Vacuum formability>
The ease of performing the forming process when vacuum forming and bonding to the MDF base material subjected to the curved surface 2R process was evaluated. If the decorative sheet follows the curved surface R and there are no wrinkles or cracks, it is indicated as ◯, and if wrinkles are generated on the curved surface R portion or if the decorative sheet is cracked, × is indicated.

<Scratch resistance>
A polylactic acid-based single-layer decorative sheet was bonded to MDF with a one-component moisture-curable polyurethane resin hot melt adhesive to prepare a test piece. The test of the pencil scratch value described in JIS K 5400 was performed using the test piece. In the test evaluation, HB or higher was evaluated as ◯ (hard, difficult to scratch), and B or lower was evaluated as x (soft, easily scratched).

  As described above in detail, the decorative sheet of the present invention has a polylactic acid resin base sheet layer having a glass transition point of 50 ° C. or higher and 90 ° C. or lower and a tensile elastic modulus of 2 GPa or higher and 3.5 GPa or lower, and a tensile elongation at break. By forming it as a transparent thermoplastic resin layer comprising a polylactic acid resin characterized in that the rate is 100% or more and 200% or less, it can be laminated to a flat substrate, V-cut processed, etc. No problems such as cracking, whitening, wrinkles, drawdown, etc., and excellent surface properties such as scratch resistance, even in wrapping laminates and three-dimensional laminates on three-dimensional uneven substrates It has a remarkable effect of being a thing.

It is explanatory drawing which shows the structure of the cross section of one Example of the polylactic acid-type single layer decorative sheet of this invention. It is explanatory drawing which shows the structure of the cross section of the other Example of the polylactic acid-type single layer decorative sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermoplastic resin sheet 2 ... Picture layer 3 ... Concealment layer 4 ... Gloss adjustment layer 5 ... Conduit pattern layer 6 ... Primer layer

Claims (2)

In a single-layer decorative sheet provided with a pattern layer on a thermoplastic resin sheet,
The thermoplastic resin sheet is a biaxially stretched sheet obtained by adding 0.1 to 10 parts by weight of an oily plasticizer to 100 parts by weight of a polylactic acid resin with a polylactic acid resin as a main ingredient, The glass transition point of the thermoplastic resin sheet is 50 to 90 ° C., the tensile breaking elongation (conforming to JIS K6781) is 2.0 to 3.5 GP, and the tensile breaking elongation is 100 to 200%. Polylactic acid single layer decorative sheet. The polylactic acid single-layer decorative sheet according to claim 1, wherein the oily plasticizer is a plant-derived oily plasticizer.

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