Method for producing decorative sheet
The method of in-line printing and irradiation-based embossing in decorative sheet manufacturing addresses misregistration issues, achieving synchronized pattern and gloss alignment for enhanced design quality and reduced production losses.
Patent Information
- Application Number
- JP2024112792
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-12
- Publication Date
- 2026-01-23
AI Technical Summary
Existing methods for manufacturing decorative sheets result in misregistration of pattern and gloss layers due to expansion and contraction of the base sheet during winding and thermal shrinkage, leading to production losses and reduced design quality.
A method involving in-line printing of a pattern layer and light-absorbing portions synchronized with the pattern, followed by laminating transparent and surface protective layers, and then irradiating with specific wavelength light to soften the layers for embossing, allowing for precise alignment of embossed portions with the pattern.
Enhances design synchronization and reduces production losses by ensuring accurate alignment of pattern and gloss states, resulting in a decorative sheet with improved aesthetic quality and reduced misregistration.
Smart Images
Figure 2026011856000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for producing a decorative sheet. [Background technology]
[0002] Conventionally, decorative sheets have been proposed in which, for example, a pattern printed layer on one side of a base sheet is laminated in this order with a pattern, a transparent thermoplastic resin layer having a textured pattern that matches the pattern, a surface protection layer that protects the surface of the transparent thermoplastic resin layer, and a gloss adjustment layer having a pattern with a gloss state that matches the pattern, thereby achieving a realistic decorative sheet with the pattern and textured pattern of the pattern printed layer and the pattern with a gloss state of the gloss adjustment layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent No. 6613719 Summary of the Invention [Problem to be solved by the invention]
[0004] However, while the technology described in Patent Document 1 can realize a realistic decorative sheet, the printing of the picture print layer, the lamination of the transparent thermoplastic resin layer, and the lamination of the gloss-adjusting layer are carried out offline. As a result, the base sheet expands and contracts when wound onto a roll, and the base sheet also shrinks thermally when the transparent thermoplastic resin layer is laminated by extrusion lamination, requiring time and effort to align the picture print layer with the gloss-adjusting layer, which can lead to misregistration and causes significant production losses.
[0005] The present invention has been made in view of the above points, and aims to provide a method for manufacturing a decorative sheet that can easily synchronize the pattern and gloss state of a pattern-printed layer, thereby obtaining a decorative sheet with a higher design quality. [Means for solving the problem]
[0006] According to one aspect of the present invention, there is provided a method for manufacturing a decorative sheet, the method comprising the steps of: printing a pattern layer on one side of a colored resin layer; printing a light-absorbing portion containing a predetermined material that is more light-absorbent than the colored resin layer at a position synchronized with the pattern of the pattern layer on the other side of the colored resin layer; after the step of printing the light-absorbing portion, laminating a transparent resin layer and a surface protective layer in this order on the side of the pattern layer opposite the colored resin layer; irradiating the laminate in which the light-absorbing portion, colored resin layer, pattern layer, transparent resin layer, and surface protective layer are laminated in this order with irradiation light having a light power of the predetermined wavelength that is stronger than the light power of light of other wavelengths; and after the step of irradiating with irradiation light, stamping an embossing plate on the surface protective layer to form an embossed portion in a position that overlaps the light-absorbing portion of the surface protective layer in a planar view, the embossed portion having greater irregularities than a portion excluding the position that overlaps the light-absorbing portion, wherein the step of printing the pattern layer and the step of printing the light-absorbing portion are performed in-line. [Effects of the Invention]
[0007] According to one embodiment of the present invention, the pattern and gloss state of the pattern layer can be easily synchronized to provide a decorative sheet with a more aesthetically pleasing design, while also reducing production losses due to registration (pattern alignment). [Brief explanation of the drawings]
[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a decorative sheet according to one embodiment of the present invention. [Figure 2] 1A to 1C are process diagrams schematically illustrating an example of a procedure for producing a decorative sheet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0009] Hereinafter, embodiments of the present technology will be described with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.
[0010] [Configuration of decorative sheet] 1, a decorative sheet 1 formed by a decorative sheet manufacturing method according to one embodiment of the present invention is formed by laminating, in this order, a colored thermoplastic resin layer (colored resin layer) 2, a pattern layer 3, a transparent thermoplastic resin layer (transparent resin layer) 4, and a surface protective layer 5, with an embossed portion 5a formed in the surface protective layer 5. Furthermore, on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3, a light absorbing portion 6 is formed in a position that matches the pattern of the pattern layer 3, and a primer layer 7 is formed so as to cover the colored thermoplastic resin layer 2 including the light absorbing portion 6.
[0011] [Colored thermoplastic resin layer] Examples of materials for the colored thermoplastic resin layer 2 include polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ionomer, acrylic acid ester, methacrylic acid ester, etc. Among these, polyolefin-based resins are preferred in terms of environmental compatibility, processability, and price. The grade and composition of the resin can also be selected taking into consideration ease of sheeting, printability, and suitability for bending.
[0012] The color of the colored thermoplastic resin layer 2 can be selected appropriately as the base color of the design layer 3. The colored thermoplastic resin layer 2 can be colored, for example, by mixing or kneading a coloring agent such as a pigment into the thermoplastic resin when sheeting it. Alternatively, a colored layer can be formed as a solid ink layer using a coating or printing method before forming the light-absorbing portion 6.
[0013] [Picture layer] The design layer 3 is a printed layer on which a design pattern is printed to impart design to the decorative sheet 1. Known printing methods can be used to form the design layer 3. The printing method is not particularly limited, but gravure printing is preferred considering productivity and design quality. For example, if the colored thermoplastic resin layer 2 is available in a rolled state, printing to form the design layer 3 can be performed using a roll-to-roll printing device. Other printing methods include offset printing, screen printing, flexographic printing, electrostatic printing, inkjet printing, and transfer printing from a transfer sheet. When using such printing methods, the design pattern of the design layer 3 can be formed by multicolor printing using the usual process colors of yellow, red, blue, and black, or by multicolor printing using special colors, in which plates of the individual colors that make up the design pattern are prepared.
[0014] Furthermore, the pattern of the pattern layer 3 may be any pattern, taking into consideration the design of the flooring or fittings. For example, a marble grain pattern can be used to evoke the image of a stone floor such as marble. For example, various wood grains or cork can be used as the pattern for a wood-based design. In addition to patterns of natural materials, artificial patterns based on these motifs or geometric patterns can also be used. Other examples of patterns include wood grain patterns composed of spring wood and autumn wood regions and vessels in the cross section of tree rings, leather (grain) patterns, stone grain patterns on the surface of stone such as marble, granite, and sandstone, sand grain patterns, tile patterns, brickwork patterns, fabric patterns, geometric shapes, letters, symbols, abstract patterns, floral patterns, landscapes, characters, and the like.
[0015] Printing ink is a mixture of a solvent and solid components such as a colorant and a binder resin. Examples of solvents include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester-based organic solvents such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chlorine-based organic solvents such as dichloromethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene; and inorganic solvents such as water. The solvents may be used alone or in combination of two or more.
[0016] Examples of binder resins include chlorine-based resins, urethane resins, acrylic urethane resins, acrylic resins, polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins (nitrocellulose), and cellulose acetate resins. Examples of chlorine-based resins include polyvinyl chloride resins such as polyvinyl chloride, chlorinated polyethylene, polyvinylidene chloride, ethylene-vinyl chloride copolymers, vinyl chloride-vinyl acetate copolymers, and vinyl chloride-vinyl acetate-(meth)acrylic copolymers, as well as polypropylene chloride and chlorinated polypropylene. Here, (meth)acrylic means acrylic or methacrylic. The binder resin may be a single type or a combination of two or more types.
[0017] Examples of colorants include inorganic pigments such as carbon black, iron black, titanium white (titanium oxide), antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; and organic pigments such as quinacridone red, isoindolinone yellow, and phthalocyanine blue. The colorants may be used alone or in combination of two or more. The solvent contained in the printing ink will eventually volatilize, so the design layer 3 is mainly formed from solid components such as colorants and binder resins.
[0018] The printing ink may also contain other components such as stabilizers, plasticizers, catalysts, and curing agents. The printing ink may be selected based on the printing method. It is preferable to select the printing ink taking into consideration adhesion to the colored thermoplastic resin layer 2, printability, and weather resistance as a flooring material or fitting. The thickness of the design layer 3 can be adjusted appropriately, taking into consideration the decorative properties required of the design layer 3, the three-dimensional formability of the decorative sheet 1, and the like. The thickness of the design layer 3 is typically 1 μm or more and 1 mm or less, preferably 2 μm or more and 0.1 mm or less, and more preferably 2 μm or more and 50 μm or less.
[0019] To improve the adhesion between the design layer 3 and the transparent thermoplastic resin layer 4, an adhesive layer (not shown) may be provided on the surface of the design layer 3 that comes into contact with the transparent thermoplastic resin layer 4. By strengthening this adhesion, the decorative sheet 1 can be given the ability to be bent to conform to curved surfaces and right-angled surfaces. The resin used in the adhesive layer (not shown) is not particularly limited. For example, a two-component curing urethane resin can be used as the resin used in the adhesive layer. The adhesive resin may also be bonded to the design layer 3 with a urethane adhesive. For example, a coating device or a gravure printing device can be used to apply the resin used in the adhesive layer (not shown).
[0020] Furthermore, a glittering layer (not shown) may be provided between the picture layer 3 and the transparent thermoplastic resin layer 4 in order to suitably impart design effects such as a sense of depth and brightness to the decorative sheet 1. The glittering layer (not shown) preferably contains a glittering pigment and a binder resin. Examples of glittering pigments include pearlescent pigments and metallic pigments. Pearlescent pigments are particularly preferred because they can prevent a decrease in the light transmittance of the glittering layer and therefore do not impair the visibility of the picture layer 3.
[0021] Pearl pigments are pigments that can impart pearlescent luster. Examples include base particles whose surfaces are coated with a metal oxide. The base particles are preferably scaly particles such as mica. Examples of metal oxides include oxides of metals such as titanium, iron, zirconium, silicon, aluminum, and cerium. The metal oxides may be used alone or in combination. Specific examples include oxide-coated mica such as titanium mica, iron oxide-coated mica, iron oxide-coated mica titanium, Prussian blue-coated mica titanium, Prussian blue-iron oxide-coated mica titanium, chromium oxide-coated mica titanium, carmine-coated mica titanium, organic pigment-coated mica titanium, titanium oxide-coated mica, and titanium oxide-coated synthetic mica; oxide-coated glass powder such as titanium oxide-coated glass powder and iron oxide-coated glass powder; oxide-coated metal particles such as titanium oxide-coated aluminum powder; scaly flakes such as basic lead carbonate, lead hydrogen arsenate, and bismuth oxide chloride; fish scale powder, shell fragments, and pearl fragments.
[0022] Examples of metallic pigments include pigments made of metals such as aluminum, brass, stainless steel, tin, zinc, copper, nickel, gold powder, and silver, and alloys of these metals. The metallic pigments may be used alone or in combination of two or more.
[0023] From the viewpoint of providing excellent design effects, for example, when forming the glittering layer using gravure printing, the average particle diameter of the glittering pigment is preferably 40 μm or less, and more preferably 30 μm or less. From the same viewpoint, the ratio of [average particle diameter of glittering pigment / thickness of glittering layer] is preferably 0.01 or more and 15 or less, and more preferably 0.5 or more and 10 or less. In this specification, "average particle diameter" refers to the value that can be determined as the mass average value D50 in particle size distribution measurement using laser light diffraction method.
[0024] Examples of binder resins include thermoplastic resins and cured products of curable resin compositions, with the cured products of curable resin compositions being preferred from the viewpoint of durability. Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation curable resin compositions. From the viewpoint of interlayer adhesion, the cured products of thermosetting resin compositions are preferred.
[0025] Examples of thermosetting resin compositions used in the glossy layer include polyester resin compositions, epoxy resin compositions, polyurethane resin compositions, aminoalkyd resin compositions, melamine resin compositions, guanamine resin compositions, urea resin compositions, and thermosetting acrylic resin compositions. These thermosetting resin compositions include monomers and / or prepolymers constituting each resin, and a curing agent added as needed. The ionizing radiation-curable resin composition used in the glossy layer can be the same as the ionizing radiation-curable resin composition of the surface protective layer 5 described below.
[0026] The content of the glittering pigment in the glittering layer is preferably 10 to 90 parts by mass, and more preferably 50 to 80 parts by mass, relative to 100 parts by mass of the binder resin. By setting the content of the glittering pigment to 10 parts by mass or more, it is possible to impart a sufficient glossy appearance, and by setting it to 90 parts by mass or less, it is possible to prevent impairment of the visibility of the design layer described below. From the same viewpoint, the thickness of the glittering layer is preferably 1 μm to 30 μm, and more preferably 5 μm to 20 μm.
[0027] The glittering layer can be formed into any pattern depending on the design desired. Examples include wood grain, leather, stone, sand, tile, brickwork, fabric, geometric shapes, letters, symbols, abstract patterns, floral patterns, landscapes, and characters. It is preferable that the arbitrary pattern have shading to further enhance the design effect. Shading may be formed by varying the size or thickness of the halftone dots, but it is preferable to form it by varying the density of the halftone dots (i.e., the size of the halftone dots is uniform and the shading is formed by the density of the halftone dots).
[0028] The glittering layer can be formed, for example, by applying a coating liquid containing a glittering pigment and a binder resin using a general-purpose printing method such as gravure printing. When the shade of the glittering layer is formed by the density of halftone dots, the halftone dots on the printing plate can be formed using an FM (frequency modulation) screen.
[0029] [Transparent thermoplastic resin layer] The transparent thermoplastic resin layer 4 is a resin layer that provides thickness and depth for design purposes, as well as protecting the design layer 3 and imparting good surface properties to improve the weather resistance and abrasion resistance of the decorative sheet 1. Materials that can be used for the transparent thermoplastic resin layer 4 include, for example, vinyl chloride resin, acrylic resin, and polyolefin-based resin (polypropylene resin, polyethylene resin). In particular, polyolefin-based resins are preferred in terms of environmental compatibility, processability, and cost. The grade and composition of the resin can be selected taking into consideration not only environmental compatibility, processability, and cost, but also ease of sheeting, printability, and suitability for bending. When selecting a material for bending, it is important to consider the prevention of whitening or cracking at the bent portion.
[0030] A lamination method can be used as a method for forming the transparent thermoplastic resin layer 4. Furthermore, for example, when the transparent thermoplastic resin layer 4 and an adhesive layer (not shown) are formed simultaneously, a method can be used in which they are formed by co-extrusion.
[0031] [Surface protective layer] The surface protective layer 5 is a layer that imparts surface properties such as abrasion resistance to the decorative sheet 1. The surface protective layer 5 also adjusts the surface gloss of the decorative sheet 1. The surface protective layer 5 may be a single layer or multiple layers. For example, the surface protective layer 5 may be formed by providing two layers, a first surface protective layer (not shown) and a second surface protective layer (not shown), in this order on the transparent thermoplastic resin layer 4. When providing a surface protective layer 5 consisting of a first surface protective layer (not shown) and a second surface protective layer (not shown), each layer may be applied and the coating cured using a known coating device, heat drying device, or ionizing radiation irradiation device depending on the type of curable resin.
[0032] The surface protective layer 5 is primarily composed of a curable resin. That is, it is preferable that the resin component of the surface protective layer 5 is substantially composed of a curable resin. "Substantially" refers to, for example, 80 parts by mass or more when the total resin is 100 parts by mass. The surface protective layer 5 may contain weathering agents, plasticizers, stabilizers, fillers, dispersants, colorants such as dyes and pigments, solvents, etc., as needed.
[0033] Examples of materials that can be used for the surface protective layer 5 include ionizing radiation-curable resins and two-component curable urethane-based resins. The ionizing radiation-curable resins are not particularly limited. For example, transparent resins primarily composed of prepolymers (including oligomers) and / or monomers containing radically polymerizable double bonds in the molecule that can undergo polymerization and crosslinking reactions upon exposure to ionizing radiation such as infrared rays, ultraviolet rays, or electron beams can be used. These prepolymers or monomers can be used alone or in combination. Specific examples of prepolymers or monomers include compounds containing radically polymerizable unsaturated groups such as (meth)acryloyl groups and (meth)acryloyloxy groups, and cationically polymerizable functional groups such as epoxy groups in the molecule. Polyene / thiol-based prepolymers, which are combinations of polyene and polythiol, are also preferred. Here, the term "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group.
[0034] Examples of prepolymers having a radically polymerizable unsaturated group include polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, triazine (meth)acrylate, silicone (meth)acrylate, etc. The molecular weight of these is preferably about 250 to 100,000.
[0035] Furthermore, examples of the monomer having a radically polymerizable unsaturated group include monofunctional monomers such as methyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and phenoxyethyl(meth)acrylate. Examples of the polyfunctional monomer include diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylpropane tri(meth)acrylate, trimethylolpropane ethylene oxide tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.
[0036] Examples of prepolymers having a cationically polymerizable functional group include prepolymers of epoxy resins such as bisphenol-type epoxy resins and novolac-type epoxy compounds, and vinyl ether resins such as fatty acid vinyl ethers and aromatic vinyl ethers. Examples of polyene-based prepolymers include those obtained by adding allyl alcohol to both ends of polyurethanes made from diols and diisocyanates, and examples of thiol-based prepolymers include polythiols such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate.
[0037] The ionizing radiation may be, for example, electromagnetic waves or charged particles having energy sufficient to cause a curing reaction of molecules in an ionizing radiation-curable resin (composition). Examples of the curing reaction include crosslinking and curing reactions. The ultraviolet light source may be, for example, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light, or a metal halide lamp. The wavelength of the ultraviolet light is preferably, for example, 190 nm or more and 380 nm or less. The electron beam source may be, for example, an electron beam accelerator such as a Cockcroft-Walton type, a Van de Graaf type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, or a high-frequency type. In particular, those capable of irradiating electrons having an energy of 100 keV or more and 1000 keV or less (more preferably, an electron having an energy of 100 keV or more and 300 keV or less) are preferred.
[0038] The two-component curing urethane resin is not particularly limited. For example, a resin containing a polyol component having OH groups as a base component and an isocyanate component as a curing agent component can be used. Examples of the polyol component having OH groups include acrylic polyol, polyester polyol, polyether polyol, and epoxy polyol. Examples of the isocyanate component include tolylene diisocyanate, hexamethylene diisocyanate, and metaxylene diisocyanate.
[0039] [Embossed part] An embossed portion 5a consisting of a concave-convex pattern is formed on the surface of the surface protection layer 5 to impart a given design. Examples of concave-convex patterns include the vascular grooves of a wood grain board, the uneven surface of a stone slab (such as the cleavage plane of granite), the texture of a cloth surface, a matte finish, a sand grain, a hairline, and linear grooves. The embossed portion 5a is provided so that the concave-convex pattern is in harmony with the pattern of the pattern layer 3. This allows the decorative sheet 1 to be given a good texture close to that of actual wood or stone.
[0040] The concave-convex pattern can be formed, for example, by embossing. The embossing method is not particularly limited. For example, a known sheet-fed embossing machine or rotary embossing machine can be used.
[0041] [Light absorbing part] The light-absorbing portions 6 are formed of a material that has light-absorbing properties for light of a predetermined wavelength, for example, a material that has infrared absorbing properties. As will be described in detail later, the light-absorbing portions 6 are provided to facilitate the formation of the embossed portions 5a in desired positions (positions that are in sync with the pattern on the pattern layer 3), that is, to easily impart to the decorative sheet 1 a texture similar to that of actual wood or stone.
[0042] In this embodiment, the light absorbing portion 6 is formed using, for example, ink containing a material having an infrared absorbing effect. As the ink used for the light absorbing portion 6, for example, urethane-based printing ink can be used.
[0043] The color of the ink used for the light-absorbing portions 6 is not particularly limited, and a dark black ink or a colorless, transparent, or light-colored (light-colored) ink that is relatively nearly transparent can be used. The color (shade) of the ink may be selected appropriately depending on the design to be expressed, etc. Because the light-absorbing portions 6 are provided on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3, even when the light-absorbing portions 6 are printed using dark black ink, the visual impact of the light-absorbing portions 6 on the decorative sheet 1 can be reduced, and there is no need to make the decorative sheet 1 a dark color in consideration of the visual impact of the light-absorbing portions 6, and a gloss matte design can be expressed even with a light-colored decorative sheet.
[0044] The material having infrared absorption properties in the gloss matte developing pattern portion 8 can be at least one or more of inorganic materials such as carbon black, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), lanthanum hexaboride (LaB6), cesium-doped tungsten oxide, etc. Furthermore, organic materials such as near-infrared absorbing materials, infrared absorbing materials, and phthalocyanine-based materials, as well as existing materials having infrared absorption properties, can also be used.
[0045] The light absorbing portions 6 are arranged at positions that are synchronized with the pattern of the pattern layer 3. For example, in the case of a wood grain patterned pattern layer 3, the gloss matte developing pattern portions 8 are formed at positions that overlap with the wood grain board conduit grooves of the pattern layer 3 in a planar view. Note that synchronization here means that the light absorbing portions 6 are formed at positions that overlap with the pattern of the pattern layer 3 in a planar view.
[0046] The thickness of the light absorbing parts 6 may be any thickness that can soften the transparent thermoplastic resin layer 4 and the surface protective layer 5 to an extent that allows sufficient formation of unevenness in the surface protective layer 5 during embossing, which will be described later. In order to obtain a sufficient gloss matte effect, the difference in gloss between the areas where the light absorbing parts 6 are formed and the areas where they are not formed is preferably 5 or more, i.e., the image density level is preferably 60% or more.
[0047] [Light of a specified wavelength] As described above, the light absorbing portion 6 is made of a material that has a light absorbing property for light of a predetermined wavelength. Examples of light of a predetermined wavelength include infrared light, ultraviolet light, visible light, electron beams, X-rays, and ion beams.
[0048] [Primer layer] The primer layer 7 is a base layer that improves adhesion and corrosion resistance with a substrate (not shown) to which the decorative sheet 1 is attached. The primer layer 7 is provided on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3. The primer layer 7 is formed using, for example, polyester resin, organic additives, pigments, etc. The primer layer 7 may contain an anti-rust pigment to improve corrosion resistance. The thickness of the primer layer 7 is, for example, in the range of 1 μm to 10 μm. The primer layer is not necessarily provided.
[0049] [Method for manufacturing decorative sheet] a step of printing a pattern layer on one side of the colored resin layer; a step of printing a light absorbing portion containing a predetermined material that is more light absorbing than the colored resin layer for light of a predetermined wavelength, at a position synchronized with the pattern of the pattern layer on the other side of the colored resin layer; a step of laminating a transparent resin layer and a surface protective layer in this order on the side of the pattern layer opposite the colored resin layer after the step of printing the light absorbing portion; a step of irradiating a laminate in which the light absorbing portion, colored resin layer, pattern layer, transparent resin layer, and surface protective layer are laminated in this order with irradiation light having a light power of a predetermined wavelength that is stronger than the light power of light of other wavelengths; and a step of embossing the surface protective layer with an embossing plate after the step of irradiating light, to form an embossed portion that overlaps the light absorbing portion of the surface protective layer in a position that overlaps with the light absorbing portion in a planar view, the embossing portion having greater irregularities than a portion excluding the position that overlaps with the light absorbing portion, and the step of printing the pattern layer and the step of printing the light absorbing portion are performed in-line.
[0050] An example of a method for producing a decorative sheet according to this embodiment will be described with reference to FIG. First, a colored thermoplastic resin layer 2 is formed (FIG. 2(a)). For example, it is formed using PBT (polybutylene terephthalate resin) to a thickness of 50 μm. The colored thermoplastic resin layer 2 is not limited to PBT resin, and may also be made of PE resin, PP resin, etc. The thickness of the colored thermoplastic resin layer 2 may be within a range of 35 μm to 130 μm.
[0051] Next, one surface of the colored thermoplastic resin layer 2 is printed using, for example, a urethane-based printing ink to form a design layer 3 (step of printing a design layer). Next, the light-absorbing portions 6 are printed on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3 (step of printing the light-absorbing portions) (FIG. 2(b)). For example, the light-absorbing portions 6 are printed at predetermined positions that are in harmony with the pattern of the pattern layer 3 using a black ink containing carbon black, which is a urethane-based printing ink.
[0052] In this case, the printing of the pattern layer 3 and the printing of the light absorbing parts 6 are carried out in-line. Here, "in-line" means that after the printing of the pattern layer 3, the printing of the light absorbing parts 6 is carried out continuously following the printing of the pattern layer 3, without winding up the laminate of the colored thermoplastic resin layer 2 and the pattern layer 3 into a roll.
[0053] Specifically, after printing the pattern layer 3, the laminate of the colored thermoplastic resin layer 2 and the pattern layer 3 is inverted, and then the light absorbing portions 6 are printed on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3. Then, a primer layer 7 is formed by laminating, for example, a polyester-based resin on the colored thermoplastic resin layer 2 including the light absorbing portions 6 so as to cover the light absorbing portions 6 (FIG. 2(c)).
[0054] Next, a transparent thermoplastic resin layer 4 is formed by laminating, for example, 80 μm of PP (polypropylene) resin using an extrusion lamination method on the surface of the design layer 3 opposite the colored thermoplastic resin layer 2 (FIG. 2(d)). Furthermore, a surface protective layer 5 containing, for example, an acrylic resin composition as its main component is laminated on the transparent thermoplastic resin layer 4. As a result, the design layer 3, the transparent thermoplastic resin layer 4, and the surface protective layer 5 are laminated in this order on one surface of the colored thermoplastic resin layer 2.
[0055] The thickness of the transparent thermoplastic resin layer 4 may be within a range of 35 μm to 130 μm. An adhesive layer made of an adhesive resin containing a urethane adhesive may be provided between the design layer 3 and the transparent thermoplastic resin layer 4.
[0056] Next, an after-embossing step is performed, in which the laminate in which these layers are stacked as shown in Fig. 2(d) is irradiated with infrared light (irradiation light) from the surface protective layer 5 side (irradiation light irradiation step) (Fig. 2(e)), and immediately after the infrared irradiation, an embossing plate 20 such as an embossing roll is pressed onto the surface of the surface protective layer 5 (embossed portion forming step) (Fig. 2(f)). This forms embossed portions 5a, and the decorative sheet 1 is formed (Fig. 2(g)).
[0057] The embossing plate 20 has a textured pattern in which the intervals between the projections and recesses are relatively short, such as a matte finish, and multiple projections and recesses are included in the area that overlaps with the light absorbing portion 6 in plan view, as shown in Fig. 2(g). Infrared irradiation is performed so that the transparent thermoplastic resin layer 4 and the surface protective layer 5 are softened by the infrared irradiation, and a textured shape that can satisfactorily express a gloss matte design can be formed when the embossing plate 20 is pressed.
[0058] Here, the light absorbing portions 6 are formed of black ink having infrared absorbing properties. Therefore, when the laminate is irradiated with infrared rays, the transparent thermoplastic resin layer 4 and the surface protective layer 5 are more likely to soften in the portions that overlap with the light absorbing portions 6 of the surface protective layer 5 in a plan view than in the portions that do not overlap with the light absorbing portions 6. In other words, after infrared irradiation, the transparent thermoplastic resin layer 4 and the surface protective layer 5 have portions that are more likely to soften and portions that are less likely to soften.
[0059] When the embossing plate 20 is pressed against the transparent thermoplastic resin layer 4 and the surface protective layer 5 in this state, unevenness is likely to be formed in the softened portions and is less likely to be formed in the portions that do not soften, and therefore unevenness is likely to be formed in the softened portions of the transparent thermoplastic resin layer 4 and the surface protective layer 5, i.e., in the portions that overlap with the light absorbing portions 6 in plan view. As a result, shapes with larger unevenness are likely to be formed in the positions of the transparent thermoplastic resin layer 4 and the surface protective layer 5 that overlap with the light absorbing portions 6 in plan view compared to positions that do not overlap with the light absorbing portions 6, and embossed portions 5a consisting of large uneven shapes are formed on the surface of the surface protective layer 5.
[0060] This allows the embossed portions 5a to be formed in positions that are in sync with the pattern of the pattern layer 3, meaning that, without the need for highly accurate positioning, the embossed portions 5a can be easily formed in sync with the pattern of the pattern layer 3. Therefore, it is possible to provide a decorative sheet 1 that has a texture close to the real thing, expresses good colors that are close to the real thing, and has excellent design properties.
[0061] The timing for pressing the embossing plate onto the transparent thermoplastic resin layer 4 and the surface protective layer 5 after infrared irradiation is not limited to immediately after infrared irradiation, but may be any timing that allows the plate to be pressed onto the surfaces of the transparent thermoplastic resin layer 4 and the surface protective layer 5 to selectively form an uneven shape in the parts softened by infrared irradiation.
[0062] In addition, other processes may be included between the process of creating the surface protection layer 5 and the process of performing infrared irradiation, and the key point is that the infrared irradiation should be performed in a state where the transparent thermoplastic resin layer 4 and the surface protection layer 5 have been formed.
[0063] Furthermore, the light absorbing portion 6 is printed after the picture layer 3 is printed, but the picture layer 3 may be printed after the light absorbing portion 6 is printed, and the printing order is not limited as long as the printing of the picture layer 3 and the printing of the light absorbing portion 6 are performed inline.
[0064] [Effects of this embodiment] (1) By pressing the embossing plate 20 after infrared irradiation, it is possible to impart a large uneven shape to the portion that overlaps with the light-absorbing portion 6 in a plan view. In other words, the embossed portion 5a can be easily formed in the desired position without having to perform high-precision positioning of the area where the uneven shape is to be formed. As a result, a decorative sheet with excellent design properties can be easily obtained, and the time required for registration can be reduced. Furthermore, since the light absorbing portion 6 is provided in harmony with the pattern of the pattern layer 3, an embossed portion 5a can be formed in harmony with the pattern of the pattern layer 3, that is, a gloss matte effect in harmony with the pattern can be easily achieved.
[0065] (2) Because the process of printing the design layer 3 and the process of printing the light-absorbing portions 6 are performed inline, the design layer 3 and the light-absorbing portions 6 can be synchronized with each other with higher accuracy. Here, if the process of printing the design layer 3 and the process of printing the light-absorbing portions 6 are performed offline, and the design layer 3 is printed, then temporarily wound onto a roll, and then unwound from the roll to print the light-absorbing portions 6, the winding onto the roll and unwound from the roll may cause expansion and contraction of the colored thermoplastic resin layer 2, which serves as the base material. Because the light-absorbing portions 6 must be positioned in synchronization with the design of the design layer 3, if expansion and contraction occurs in the colored thermoplastic resin layer 2, for example, the positional relationship between the gravure cylinder and the colored thermoplastic resin layer 2 may be shifted, causing the printing location of the light-absorbing portions 6 on the colored thermoplastic resin layer 2 to deviate from the intended position. As a result, the positional relationship between the design of the design layer 3 and the light-absorbing portions 6 in a planar view may be shifted, resulting in a decrease in synchronization accuracy.
[0066] In the present embodiment, the printing of the picture layer 3 and the printing of the light-absorbing portions 6 are performed in-line, and the step of printing the light-absorbing portions 6 is performed after the step of printing the picture layer 3 without winding it onto a roll. This makes it possible to prevent the colored thermoplastic resin layer 2 from expanding and contracting due to winding and unwinding onto a roll, and thus to prevent a decrease in the synchronization accuracy between the picture of the picture layer 3 and the light-absorbing portions 6. Furthermore, since the transparent thermoplastic resin layer 4 is formed by lamination after the picture layer 3 and the light-absorbing portions 6 are formed, even if thermal shrinkage occurs in the laminate due to the lamination, it is possible to avoid a decrease in the synchronization accuracy between the picture of the picture layer 3 and the light-absorbing portions 6 due to this thermal shrinkage. This makes it possible to achieve a design expression that is closer to the real thing.
[0067] Furthermore, because misregistration can be suppressed in this way, production losses can be reduced compared to when registering is performed offline. Furthermore, since the embossed portion can be formed without changing the pattern of the embossing plate according to the pattern of the pattern layer 3, the time wasted for changing the embossing plate can be reduced, and productivity can be improved.
[0068] (3) By providing the embossed portion 5a having a large uneven shape, a glossy matte finish is achieved, which can prevent the glossy matte pattern from coming off. Therefore, for example, a glossy matte finish can be achieved even in flooring materials.
[0069] (4) In the decorative sheet 1 according to this embodiment, at least one inorganic material selected from the group consisting of carbon black, tin-doped indium oxide, antimony-doped tin oxide, lanthanum hexaboride, and cesium-doped tungsten oxide can be used as the material in the light-absorbing portion 6 that has light-absorbing properties for infrared rays. This allows the transparent thermoplastic resin layer 4 and the surface protective layer 5 to be softened more reliably by infrared irradiation in the areas overlapping with the light absorbing parts 6, and more reliably allows the areas overlapping with the light absorbing parts 6 to be strongly embossed. As a result, a decorative sheet with excellent design properties can be obtained more easily. [Example]
[0070] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.
[0071] Example 1 A wood grain pattern is printed using urethane-based printing ink on one surface of a colored thermoplastic resin layer 2 made of a 50 μm-thick PBT (polybutylene terephthalate) resin to form a pattern layer 3. Next, without winding up the laminate of the colored thermoplastic resin layer 2 and the pattern layer 3 into a roll, the laminate is inverted, and light-absorbing portions 6 are printed in-line using a black ink containing carbon black, which is a urethane-based printing ink, on the surface of the colored thermoplastic resin layer 2 opposite the pattern layer 3, at predetermined positions that are in sync with the pattern of the pattern layer 3. Specifically, the light-absorbing portions 6 are formed at positions that overlap with the wood grain board conduit grooves of the wood grain pattern pattern layer 3 in a plan view.
[0072] Next, a polyester resin is laminated on the colored thermoplastic resin layer 2 containing the light-absorbing portions 6 to form a primer layer 7. Subsequently, a PP (polypropylene) resin is laminated on the surface of the design layer 3 opposite the colored thermoplastic resin layer 2 using an extrusion lamination method, via an adhesive layer made of an adhesive resin containing a urethane adhesive, to form a transparent thermoplastic resin layer 4 having a thickness of 80 μm. Furthermore, a surface protective layer 5 containing an acrylic resin composition as its main component is laminated on the transparent thermoplastic resin layer 4. As a result, the design layer 3, adhesive layer, transparent thermoplastic resin layer 4, and surface protective layer 5 are laminated in this order on one surface of the colored thermoplastic resin layer 2.
[0073] Subsequently, an after-embossing step is carried out, in which infrared rays (irradiation light) are irradiated from the surface protection layer 5 side, and an embossing plate 20 with a matte pattern is pressed onto the surface of the surface protection layer 5 immediately after the infrared irradiation.
[0074] This resulted in a decorative sheet in which embossed portions 5a consisting of larger irregularities were formed in the areas of the surface protective layer 5 and the transparent thermoplastic resin layer 4 that overlap the light absorbing portions 6 in a planar view compared to the non-overlapping areas.
[0075] (Comparative Example 1) Printing of a pattern layer and printing of a gloss-adjusting layer for expressing a pattern depending on the gloss state are carried out offline to obtain a decorative sheet in which the pattern of the pattern layer and the pattern depending on the gloss state are synchronized. That is, first, a wood grain pattern was printed using urethane printing ink on one surface of a colored thermoplastic resin layer 2 made of a 50 μm thick PBT (polybutylene terephthalate) resin to form a pattern layer 3.
[0076] Next, the colored thermoplastic resin layer 2 was inverted in-line, and then a polyester resin was applied to the surface of the colored thermoplastic resin layer opposite to the design layer 3 to form a primer layer.
[0077] Next, PP (polypropylene) resin was laminated on the surface of the design layer 3 opposite the colored thermoplastic resin layer 2 using an extrusion lamination method, via an adhesive layer made of an adhesive resin containing a urethane adhesive, to form a transparent thermoplastic resin layer 4 with a thickness of 80 μm. Furthermore, a surface protective layer 5 containing an acrylic resin composition as its main component was laminated on the transparent thermoplastic resin layer 4. Then, a gloss-adjusting layer was printed on the surface protective layer 5 while adjusting the registration and production conditions to match the wood grain pattern of the design layer 3, thereby obtaining a decorative sheet.
[0078] (Comparative Example 2) Printing of a picture layer and printing of a gloss-adjusting layer for expressing a pattern depending on the gloss state were carried out offline to obtain a decorative sheet in which the picture of the picture layer and the pattern depending on the gloss state are not synchronized. That is, first, a wood grain pattern was printed using urethane printing ink on one surface of a colored thermoplastic resin layer 2 made of a 50 μm thick PBT (polybutylene terephthalate) resin to form a pattern layer 3.
[0079] Next, the colored thermoplastic resin layer 2 was inverted in-line, and then a polyester resin was applied to the surface of the colored thermoplastic resin layer opposite to the design layer 3 to form a primer layer.
[0080] Next, PP (polypropylene) resin was laminated on the surface of the design layer 3 opposite the colored thermoplastic resin layer 2 using an extrusion lamination method, via an adhesive layer made of an adhesive resin containing a urethane adhesive, to form a transparent thermoplastic resin layer 4 with a thickness of 80 μm. Furthermore, a surface protective layer 5 containing an acrylic resin composition as its main component was laminated on the transparent thermoplastic resin layer 4. A gloss-adjusting layer was then printed on the surface protective layer 5 out of sync with the design of the design layer 3, to obtain a decorative sheet.
[0081] 〔evaluation〕 The decorative sheets of Example 1 and Comparative Examples 1 and 2 were each evaluated for gloss and matte design (sensory evaluation), productivity, and workability.
[0082] [Gloss Matte Design (Sensory Evaluation)] The state of gloss and matte feeling was visually evaluated for the decorative sheets of Example 1 and Comparative Examples 1 and 2. The evaluation criteria were as follows. ⊚: The gloss matte is perfectly in sync with the pattern on the pattern layer. ○: The gloss matte is in harmony with the pattern on the pattern layer. ×: The gloss matte is not synchronized with the pattern on the pattern layer.
[0083] [Productivity] ○: Almost no production loss occurs. ×: Large production losses due to misregistration and adjustment of production conditions.
[0084] [Workability (indirect time)] ◯: There is no need to change the gloss matte printing plate to match the image on the image layer. △: Some gloss matte printing plates need to be replaced to match the image on the image layer. ×: It is necessary to change the gloss matte printing plate to match the pattern of the pattern layer for each pattern. The results of the above evaluations are shown in Table 1.
[0085] [Table 1]
[0086] 〔result〕 The decorative sheet according to this embodiment was excellent in all respects of GM design, productivity, and workability. In contrast, the decorative sheet of Comparative Example 1, in which the gloss adjustment layer was arranged in a position synchronized with the pattern of the pattern layer, had a good gloss matte design, but problems with the positioning accuracy when arranging the gloss adjustment layer resulted in production losses due to misregistration, etc. Furthermore, since the gloss adjustment layer had to be printed in a position synchronized with the pattern of the pattern layer, whenever the pattern of the pattern layer was changed, a gloss matte printing plate had to be prepared for printing the gloss adjustment layer in a location corresponding to the position of the pattern of the pattern layer, which resulted in poor workability. On the other hand, the decorative sheet of Comparative Example 2, in which the gloss adjustment layer was printed regardless of the arrangement of the pattern of the pattern layer, had poor gloss matte design because the pattern of the pattern layer and the gloss adjustment layer were not synchronized, so there was no need to consider misalignment between the pattern of the pattern layer and the gloss adjustment layer, but productivity was good. Furthermore, although the pattern of the pattern layer and the gloss adjustment layer are not synchronized, it is necessary to print the gloss adjustment layer, and it was confirmed that workability is somewhat lower than when a gloss matte printing plate is not used. [Explanation of symbols]
[0087] 1 decorative sheet 2 Colored thermoplastic resin layer 3. Picture layer 4 Transparent thermoplastic resin layer 5 Surface protective layer 5a Embossed part 6 Light absorbing part 7 Primer layer
Claims
1. a step of printing a design layer on one surface of the colored resin layer; a step of printing a light absorbing portion containing a predetermined material that is more light absorbing than the colored resin layer for light of a predetermined wavelength at a position synchronized with the pattern of the pattern layer on the other surface of the colored resin layer; a step of laminating a transparent resin layer and a surface protection layer in this order on the surface of the design layer opposite to the colored resin layer after the step of printing the light absorbing portion; a step of irradiating a laminate in which the light absorbing portion, the colored resin layer, the design layer, the transparent resin layer, and the surface protective layer are laminated in this order with irradiation light having a power of light of the predetermined wavelength stronger than the power of light of other wavelengths; and a step of, after the step of irradiating with irradiation light, pressing an embossing plate onto the surface protective layer to form an embossed portion at a position of the surface protective layer that overlaps with the light absorbing portion in a plan view, the embossed portion having larger irregularities than a portion other than the position that overlaps with the light absorbing portion, A method for manufacturing a decorative sheet, characterized in that the step of printing the pattern layer and the step of printing the light-absorbing portion are carried out in-line.
2. 2. The method for manufacturing a decorative sheet according to claim 1, wherein the light of the predetermined wavelength is infrared light, and the predetermined material is a material that has light-absorbing properties for infrared light.
3. 2. The method for manufacturing a decorative sheet according to claim 1, wherein the predetermined material is at least one inorganic material selected from the group consisting of carbon black, tin-doped indium oxide, antimony-doped tin oxide, lanthanum hexaboride, and cesium-doped tungsten oxide.
Citation Information
Patent Citations
Decorative sheet
JP6613719B2