Release liner, laminate including release liner, and method for applying laminate

Abstract

To provide a release liner capable of reducing or suppressing the generation of paper dust and the like when cutting the release liner.SOLUTION: The release liner includes, in order, a release layer, a first resin layer, a paper base material, and a second resin layer. The paper base material contains recycled pulp, and the release liner has an internal bond strength of approximately 45.0 N / m or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a release liner, a laminate including the release liner, and a method for constructing the laminate.

Background Art

[0002] Conventionally, release liners having a paper substrate have been developed.

[0003] Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-224952) discloses a release paper obtained by sequentially providing a blocking coating layer and a release layer on a base paper mainly composed of wood pulp, and providing a back coating layer on the surface opposite to the release layer. The release paper has a curl such that when the release paper having a longitudinal size of 20 mm and a transverse size of 210 mm is placed on a horizontal plane with the back layer side facing up and conditioned for 10 hours in an environment of 23°C and 20% relative humidity and then held for 10 hours in an environment of 23°C and 80% relative humidity, both ends are curled toward the back layer side by an average of 2 mm or more compared to when the relative humidity is 20%.

[0004] Patent Document 2 (International Publication No. 2020 / 110689) describes a release paper including a paper substrate, a blocking layer containing a biomass-derived resin and / or a biodegradable resin on one or both sides of the paper substrate, and a release agent layer on at least one of the blocking layers.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] From the perspective of sustainability, the present inventors have attempted to adopt a paper substrate containing recycled pulp as the substrate of the release liner.

[0007] However, when using a paper base material containing recycled pulp, for example, when cutting a release liner using a cutter dedicated to the release liner, as the sharpness of the cutter deteriorates, problems such as paper dust and fuzz (which may be simply referred to as "paper dust" or "paper dust, etc.") are likely to occur in the cross section of the cut portion and the like. It has been found that the generation of such paper dust and the like, for example, when only the release liner of a laminate including a release liner and a decorative sheet is cut, and after pressure bonding to a wall surface or the like, when the release liner is peeled off, paper dust and the like adhere to the adhesive surface, and as a result, defects such as poor appearance due to unevenness or the like may occur on the surface of the sheet after construction.

[0008] The present disclosure provides a release liner capable of reducing or suppressing the generation of paper dust and the like when cutting the release liner.

Means for Solving the Problems

[0009] According to an embodiment of the present disclosure, there is provided a release liner including a release layer, a first resin layer, a paper base material, and a second resin layer in this order, wherein the paper base material contains recycled pulp, and the release liner has an internal bond strength of about 45.0 N / m or more.

[0010] According to another embodiment of the present disclosure, there is provided a laminate including the above release liner and a decorative sheet disposed via an adhesive layer on the release layer of the release liner.

[0011] According to another embodiment of the present disclosure, there is provided a construction method of applying the above laminate to a support member, including cutting a release liner with a cutter over at least a part of the length direction of the release liner in the laminate to form a cut portion, peeling off at least a part of the release liner over this cut portion to expose the adhesive layer, and applying the exposed adhesive layer to the support member.

Effects of the Invention

[0012] According to the present disclosure, it is possible to provide a release liner capable of reducing or suppressing the generation of paper dust or the like during cutting of the release liner.

[0013] The above description should not be regarded as disclosing all embodiments of the present invention and all advantages related to the present invention.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0015] Hereinafter, for the purpose of exemplifying representative embodiments of the present invention, a more detailed description will be given with reference to the drawings as necessary, but the present invention is not limited to these embodiments.

[0016] In the present disclosure, for example, the "above" in the phrase "a release layer disposed above the first resin layer" means that the release layer is directly disposed above the first resin layer, or that the release layer is indirectly disposed above the first resin layer via another layer.

[0017] In the present disclosure, for example, the "below" in the phrase "a paper substrate disposed below the first resin layer" means that the paper substrate is directly disposed below the first resin layer, or that the paper substrate is indirectly disposed below the first resin layer via another layer.

[0018] In the present disclosure, for example, the "in order" in the phrase "including a release layer, a first resin layer, a paper substrate, and a second resin layer in order" means that when focusing on the four components of the release layer, the first resin layer, the paper substrate, and the second resin layer, it means that the release liner or the laminate including the liner contains these components in this order, and other layers such as a printing layer may be interposed between these components, for example, between the first resin layer and the paper substrate.

[0019] In the present disclosure, the "sheet" includes a member called "film".

[0020] In the present disclosure, "(meth)acrylic" means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate.

[0021] A schematic cross-sectional view of a release liner according to an embodiment of the present disclosure is shown in FIG. 1. The release liner 100 in FIG. 1 includes a release layer 103, a first resin layer 105, a paper substrate 107, and a second resin layer 109 in order.

[0022] The release liner of the present disclosure has an internal bond strength of about 45.0 N / m or more in the internal bond strength test of the release liner described later. Since the release liner of the present disclosure has such an internal bond strength, when the release liner is cut, paper powder and the like can be retained inside the liner without scattering around, so that the generation of paper powder and the like can be reduced or suppressed. The internal bond strength of the release liner is preferably about 48.0 N / m or more, about 50.0 N / m or more, about 53.0 N / m or more, or about 55.0 N / m or more from the viewpoint of reducing or suppressing the generation of paper powder and the like during cutting. As the upper limit value of such internal bond strength, for example, it can be about 100 N / m or less, about 90.0 N / m or less, about 80.0 N / m or less, about 70.0 N / m or less, about 65.0 N / m or less, about 63.0 N / m or less, or about 60.0 N / m or less.

[0023] The internal bond strength of the release liner can be adjusted, for example, by the recycled pulp or the like incorporated in the paper base material described later. Such strength can be adjusted, for example, based on the fiber diameter and fiber length of the recycled pulp. When an internal bond strength test is performed on the release liner, typically, the release liner is separated into two pieces so as to break within the paper base material layer rather than at the interface between the first resin layer or the second resin layer and the paper base material (Fig. 5(b)). Therefore, the internal bond strength of the release liner can also be referred to as the in-layer bond strength of the paper base material. In addition, since the internal bond strength of the release liner can be adjusted by the fiber diameter of the recycled pulp or the like, it can also be said that such strength indirectly defines the parameters (such as fiber diameter and fiber length) related to the pulp (for example, recycled pulp) in the paper base material.

[0024] There is no particular limitation on the release layer in the release liner of the present disclosure. Examples of the release agent that can be used for the release layer include silicone-based release agents, fluorine-based release agents, or release agents containing alkyd resins, long-chain alkyl resins, and various waxes. The release agent may be a biodegradable release agent. Among them, from the viewpoint of release characteristics, it is preferable that the release agent contains a silicone-based release agent. The release agent can be used alone or in combination of two or more. The release agent may be in any form such as a solvent type, a solvent-free type, or an emulsion type, but from the viewpoint of the environment, etc., the emulsion type or the solvent-free type is preferable.

[0025] Examples of the resin that can be used for the silicone-based release agent include homopolymers or copolymers such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, diphenyldichlorosilane, phenyltrichlorosilane, methylvinyldichlorosilane, etc. Such resins can be used alone or in combination of two or more.

[0026] There is no particular limitation on the thickness of the release layer. Such thickness can be, for example, about 0.01 micrometer or more, about 0.05 micrometer or more, about 0.1 micrometer or more, about 0.5 micrometer or more, or about 1 micrometer or more, and can be about 10 micrometers or less, about 7 micrometers or less, about 5 micrometers or less, or about 3 micrometers or less. Here, the thickness of the release layer is the average value of the thicknesses of at least any 5 locations in the release layer of the release liner, measured by using a scanning electron microscope to measure the cross-section in the thickness direction of the release liner having a laminated structure. Such a thickness measurement method can be similarly used for the release liner and the thickness of each layer constituting the laminate including the liner.

[0027] The method of applying the release agent to the first resin layer is not particularly limited. As such a method, for example, known methods such as blade coating, air knife coating, rod blade coating, bar blade coating, gravure coating, bar coating, roll coating, and spray coating can be appropriately employed. In FIG. 1, the release layer is applied to the first resin layer, but the release layer may also be applied to the second resin layer. As the method of applying the release layer to the second resin layer, the same method of applying to the first resin layer can be adopted.

[0028] The first resin layer in the release liner of the present disclosure is typically a layer located between the release layer 103 and the paper substrate 107 as shown in FIG. 1, and is a layer located on the side to which the decorative sheet 201 or the like is applied as shown in FIG. 2. The first resin layer may have a single-layer structure or a multilayer structure. Here, since the first resin layer can exhibit the performance of suppressing the penetration of the release agent into the paper substrate when the release agent is applied to the paper substrate, it can also be referred to as a "sealing layer". When the first resin layer has a multilayer structure, the entire these layers can also be referred to as a "first resin layer group".

[0029] There is no particular limitation on the material of the first resin layer. Examples of such materials include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, (meth)acrylic resins, silicone resins, alkyd resins including aminoalkyds, polyvinyl alcohol, styrene acrylic resins, cellulose derivatives, polyester resins, resins having urethane bonds, melamine resins, polyvinyl chloride resins, polyvinylidene chloride resins, and epoxy resins. Here, in the present disclosure, the "resin having a urethane bond" includes, in addition to urethane resins, for example, resins prepared using at least one selected from urethane (meth)acrylate and urethane (meth)acrylate oligomers, and urethane resins can also include (meth)acrylic urethane resins and the like. Among such materials, from the viewpoint of reducing or suppressing the generation of paper dust and the like during cutting of the release liner, polyolefin resins are preferred, and polyethylene is more preferred. The material of the first resin layer can be used alone or in combination of two or more.

[0030] There is no particular limitation on the thickness of the first resin layer. Such thickness can be, for example, about 0.5 micrometers or more, about 1 micrometer or more, about 3 micrometers or more, about 5 micrometers or more, or about 10 micrometers or more, and can be about 50 micrometers or less, about 40 micrometers or less, about 30 micrometers or less, or about 20 micrometers or less. When the first resin layer has a multilayer structure, the thickness of each layer constituting it may be within such a thickness range, or the overall thickness of the first resin layer may be within such a thickness range.

[0031] There is no particular limitation on the method of applying the first resin layer to the paper substrate. As such a method, for example, known methods such as extrusion coating, blade coating, air knife coating, rod blade coating, bar blade coating, gravure coating, bar coating, roll coating, and spray coating can be appropriately adopted.

[0032] The paper substrate in the release liner of the present disclosure contains recycled pulp. The content of the recycled pulp in the paper substrate can be, for example, about 30% by mass or more, about 35% by mass or more, about 40% by mass or more, about 50% by mass or more, or about 60% by mass or more with respect to the total amount of the paper substrate, and can be about 100% by mass or less or less than about 100% by mass. Thus, even if the recycled pulp is contained in a high content in the paper substrate, if the internal bond strength of the release liner is about 45.0 N / m or more, the generation of paper dust and the like during cutting of the release liner can be reduced or suppressed. The paper substrate may have a single-layer structure or a multi-layer structure.

[0033] In the present disclosure, "recycled pulp" can be intended to mean pulp recycled from waste paper. The recycled pulp can include, for example, waste paper pulp obtained by pulping waste paper, deinked pulp obtained by removing ink after pulping waste paper, and the like. Examples of the waste paper used as a raw material include newsprint, flyers, magazines, books, office paper, envelopes, thermal paper, carbonless paper, cardboard, white cardboard, and printing paper generated from copiers or OA equipment. Magazine waste paper containing adhesives, adhesives, adhesive tapes, adhesives such as magazine back glue can also be used as a raw material for recycled pulp. The recycled pulp obtained by such materials can be used alone or in combination of two or more.

[0034] For the recycled pulp, if necessary, for example, sodium hydroxide, sodium silicate, other alkaline chemicals, deinking agents, oxidative bleaching agents, and reductive bleaching agents can be applied. In addition, for the recycled pulp, if necessary, for example, dyes, fluorescent brighteners, pH adjusters, defoamers, pitch control agents, slime control agents, etc. can also be applied.

[0035] When deinking old paper, a deinking agent can be used. Examples of deinking agents include nonionic surfactants such as fatty acid salts, higher alkyl sulfates, alkylbenzene sulfonates, higher alcohols, alkylphenols, and alkylene oxide adducts of fatty acids, anionic surfactants, cationic surfactants, amphoteric surfactants, organic solvents, proteins, enzymes, natural polymers, and synthetic polymers.

[0036] The old paper used as a raw material for recycled pulp may contain inorganic particles called ash content. Ash content refers to all inorganic particles and may be intended to be substances remaining when paper such as fillers and pigments added or coated during paper manufacturing is incinerated. Examples of such inorganic particles include calcium carbonate, talc, kaolin, titanium dioxide, and the like. From the viewpoint of reducing or suppressing the generation of paper dust and the like during cutting of the release liner, the content of inorganic particles in the paper base material is preferably about 10% by mass or less, about 5% by mass or less, about 3% by mass or less, about 1% by mass or less, about 0.5% by mass or less, or about 0.1% by mass or less based on the total amount of the paper base material, and it is more preferable that the paper base material does not contain inorganic particles.

[0037] In some embodiments, the paper base material of the present disclosure may contain pulp other than recycled pulp (for example, natural pulp derived from plants). Examples of such pulp include kraft pulp of softwood or hardwood (NKP or LKP), mechanical pulp using softwood or hardwood, such as groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemigroundwood pulp (CGP), semi-chemical pulp (SCP), and the like. Pulp other than recycled pulp can be used alone or in combination of two or more.

[0038] The content of pulp other than recycled pulp in the paper base material can be, for example, about 70% by mass or less, about 65% by mass or less, about 60% by mass or less, about 50% by mass or less, about 40% by mass or less, about 30% by mass or less, about 20% by mass or less, or about 10% by mass or less with respect to the total amount of the paper base material. As the lower limit value of such content, for example, it can be about 0% by mass or more or more than about 0% by mass.

[0039] As described above, the internal bond strength of the release liner can be paraphrased as the in-plane bond strength in the paper base material. Such internal bond strength can be adjusted by, for example, the fiber diameter and fiber length of the recycled pulp and virgin pulp other than that blended in the paper base material. Here, when the paper base material is formed using a mixed slurry of recycled pulp and virgin pulp, it is often difficult to distinguish between the recycled pulp and virgin pulp in the obtained paper base material using means such as an electron microscope. Since the internal bond strength of the release liner of the present disclosure can be said to indirectly define parameters (such as the fiber diameter and fiber length of the pulp) regarding the pulp in the paper base material (for example, the papermaking base material), it can be said to be a suitable parameter for specifying the paper base material, especially the paper base material in a mixed form of recycled pulp and virgin pulp. Therefore, the fiber diameter and fiber length of the pulp blended in the paper base material can be appropriately set so that the internal bond strength of the release liner falls within a predetermined range.

[0040] The basis weight of the paper base material can be, for example, about 10 g / m 2 or more, about 20 g / m 2 or more, about 30 g / m 2 or more, about 40 g / m 2 or more, about 50 g / m 2 or more, or about 60 g / m 2 or more, and can be about 150 g / m 2 or less, about 130 g / m 2 or less, about 100 g / m 2 or less, or about 90 g / m 2 or less.

[0041] The method for manufacturing the paper base material of the present disclosure is not particularly limited. The paper base material can be manufactured, for example, by using a pulp slurry containing recycled pulp or the like and a known papermaking method.

[0042] If necessary, the paper base material may be appropriately blended with any additives (such as sizing agents, yield improvers, paper strength enhancers, etc.) generally used in the manufacture of paper. In some embodiments, the paper base material of the present disclosure contains a paper strength enhancer. Examples of such paper strength enhancers include (meth)acrylamide-based paper strength enhancers containing components related to (meth)acrylamide as, for example, constituent units of polymers. The blending amount of the paper strength enhancer can be, for example, about 5% by mass or less, about 3% by mass or less, about 1% by mass or less, about 0.5% by mass or less, or about 0.1% by mass or less in terms of solid content based on the pulp solid content of the paper base material.

[0043] The second resin layer in the release liner of the present disclosure is typically a layer located on the opposite side of the first resin layer 105 with respect to the paper base material 107, as shown in FIG. 1. The second resin layer has, for example, the performance of protecting the paper base material. Also, in some embodiments, the second resin layer is a layer located on the opposite side of the decorative sheet 201, as shown in FIG. 2, and is the layer that is first cut with a cutter when laminating the laminate 200 in FIG. 2 to an adherend for construction. By disposing such a second resin layer with respect to the paper base material, generation of paper powder or the like during cutting of the release liner can be reduced or suppressed as compared with a release liner having no such resin layer. The second resin layer may have a single-layer structure or a multilayer structure. Here, when the second resin layer has a multilayer structure, these layers as a whole can also be referred to as the "second resin layer group".

[0044] There is no particular limitation on the material of the second resin layer, and the materials of the first resin layer described above can be used in the same manner. There is also no particular limitation on the method of applying the second resin layer to the paper base material, and the application methods in the first resin layer described above can be adopted in the same manner.

[0045] There is no particular limitation on the thickness of the second resin layer. Such thickness can be, for example, about 0.5 micrometers or more, about 1 micrometer or more, about 3 micrometers or more, about 5 micrometers or more, or about 10 micrometers or more, and can be about 50 micrometers or less, about 40 micrometers or less, about 30 micrometers or less, or about 20 micrometers or less. When the second resin layer has a multilayer structure, the thickness of each layer constituting it may be within such a thickness range, or the overall thickness of the second resin layer may be within such a thickness range.

[0046] The thickness of the release liner of the present disclosure can vary depending on handling properties, intended use, etc. Such thickness can be, for example, about 200 micrometers or less, about 180 micrometers or less, about 150 micrometers or less, or about 145 micrometers or less, and about 50 micrometers or more, about 70 micrometers or more, about 100 micrometers or more, about 110 micrometers or more, or about 120 micrometers or more. Here, the overall thickness of the release liner can be defined, for example, as the average value of the thicknesses at any at least 5 locations in the release liner measured with a thickness gauge (PC - 465N manufactured by TECLOCK).

[0047] The release liner of the present disclosure can also be defined by basis weight instead of thickness. Such basis weight can be, for example, about 200 g / m 2 or less, about 180 g / m 2 or less, about 150 g / m 2 or less, about 140 g / m 2 or less, about 130 g / m 2 or less, or about 120 g / m 2 or less, about 50 g / m 2 or more, about 60 g / m 2 or more, about 70 g / m 2 or more, about 80 g / m 2 or more, about 90 g / m 2 or more, or about 100 g / m 2 or more.

[0048] The release liner of the present disclosure can reduce or suppress the generation of paper dust and the like when cut. The generation of paper dust and the like occurs, for example, when only the release liner of a laminate including a release liner and a decorative sheet is cut, and after pressure bonding to a wall surface or the like, when the release liner is peeled off, paper dust and the like adhere to the adhesive surface, and as a result, defects such as poor appearance due to unevenness or the like may occur on the surface of the decorative sheet after construction. The release liner of the present disclosure can improve such defects and thus can be suitably used for decorative sheets.

[0049] For the release liner of the present disclosure, a laminate can be obtained by applying an arbitrary member to the release layer of the liner. Examples of such an arbitrary member include a decorative sheet. Such a decorative sheet can be disposed on the release layer 203 of the release liner via an adhesive layer 202, for example, as shown in FIG. 2. The decorative sheet can be bonded to the release layer after applying an adhesive layer to the release layer, or the decorative sheet can be bonded via the adhesive layer after applying an adhesive layer to the decorative sheet.

[0050] The adhesive layer is detachable from the release layer and is typically a layer applied to an adherend, such as a support member described later, together with the decorative sheet.

[0051] There is no particular limitation on the material of the adhesive layer, and for example, generally used solvent-based, emulsion-based, pressure-sensitive, heat-sensitive, thermosetting, or ultraviolet-curable adhesives such as (meth)acrylic-based, polyolefin-based, polyurethane-based, polyester-based, and rubber-based adhesives can be used. Among them, a pressure-sensitive adhesive is preferable from the viewpoints of the workability and reworkability of the decorative sheet.

[0052] There are no particular restrictions on the materials for the pressure-sensitive adhesive. For example, (meth)acrylic polymers, natural rubbers, synthetic rubbers, polyester-based polymers, polyether-based polymers, polyurethane-based polymers, silicone-based polymers, or other polymers can be used. Among them, pressure-sensitive adhesives based on (meth)acrylic polymers are preferred because they are excellent in transparency, weather resistance, and adhesiveness.

[0053] As optional components, the adhesive layer can be blended with, for example, tackifying resins, crosslinking agents, conductive fillers, fillers (filler materials) such as heat conductive fillers, silane coupling agents, plasticizers, thickeners, pigments, dyes, flame retardants, antioxidants, ultraviolet absorbers, stabilizers, etc. The optional components can be used alone or in combination of two or more.

[0054] There are no particular restrictions on the thickness of the adhesive layer. For example, it can be about 5 micrometers or more, about 10 micrometers or more, or about 20 micrometers or more, and can be about 100 micrometers or less, about 80 micrometers or less, or about 50 micrometers or less.

[0055] The decorative sheet includes a decorative layer. The decorative layer is not limited to the following, but includes, for example, a color layer exhibiting a painted color, such as light colors like white and yellow, and dark colors like red, brown, green, blue, gray, and black; a pattern layer for imparting patterns such as wood grain, stone grain, geometric patterns, leather patterns, logos, figures, characters, numbers, symbols, photographs, and patterns to the article; a relief (embossed pattern) layer provided with an uneven shape on the surface; and combinations thereof. The decorative layer may have a single-layer structure or a laminated structure.

[0056] The decorative layer is not limited to the following, but can be applied directly or indirectly via a bonding layer or the like to the whole or part of, for example, the surface layer described later.

[0057] Examples of the material for the color layer include, but are not limited to, inorganic pigments such as carbon black, lead yellow, yellow iron oxide, red iron oxide, and bengala, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, azo lake pigments, indigo pigments, perinone pigments, perylene pigments, quinophthalone pigments, dioxazine pigments, and quinacridone pigments such as quinacridone red. A material in which such pigments are dispersed in a binder resin can be used. The binder resin can be used alone or in combination of two or more. Examples of such resins include thermoplastic resins, thermosetting resins, and radiation-curable resins. Specific examples thereof include fluorine-based resins, polyester-based resins such as PET and PEN, (meth)acrylic resins, polyolefin-based resins such as polyethylene and polypropylene, thermoplastic elastomers, polycarbonate resins, polyamide resins, ABS resins, acrylonitrile-styrene resins, polystyrene resins, vinyl chloride-based resins, and resins having a urethane bond. Among them, vinyl chloride-based resins are preferred from the viewpoint of flame retardancy and the like. Here, in the present disclosure, the "vinyl chloride-based resin" may include not only a homopolymer of vinyl chloride but also a copolymer of a vinyl chloride monomer and another monomer copolymerizable therewith. As another monomer copolymerizable with the vinyl chloride monomer, those conventionally generally used can be used without particular limitation. For example, vinyl esters such as vinyl acetate, alkyl vinyl ethers such as ethyl vinyl ether and octyl vinyl ether, α-olefins such as ethylene and propylene, monounsaturated acids such as acrylic acid and methacrylic acid, and alkyl esters such as methyl esters of these monounsaturated acids, diunsaturated acids such as maleic acid and itaconic acid, alkyl esters such as methyl esters of these diunsaturated acids, vinylidene compounds such as vinylidene chloride, and one or a mixture of two or more of unsaturated nitriles such as acrylonitrile can be mentioned. There is no particular limitation on the use ratio of these monomers. For example, they can be used in a ratio of about 30% by mass or less or about 20% by mass or less with respect to the vinyl chloride monomer.

[0058] The color layer can be formed by using such materials and coating methods such as gravure coating, roll coating, die coating, bar coating, knife coating, etc.

[0059] The pattern layer is not limited to the following, but for example, patterns such as patterns, logos, and designs can be directly applied to the surface layer described later using printing methods such as gravure direct printing, gravure offset printing, inkjet printing, laser printing, screen printing, etc., or films, sheets, etc. having patterns, logos, designs, etc. formed by coating, punching, etching, etc. such as gravure coating, roll coating, die coating, bar coating, knife coating can also be used. As the material of the pattern layer, for example, the same materials as those used in the color layer can be used.

[0060] As the relief layer, a thermoplastic resin film having an uneven shape on the surface by a conventionally known method, for example, embossing, scratching, laser processing, dry etching processing, or heat pressing processing can be used. A thermosetting or radiation-curable resin such as a curable (meth)acrylic resin can be applied to a release liner having an uneven shape, cured by heating or radiation irradiation, and the release liner can be removed to form the relief layer.

[0061] The thermoplastic resin, thermosetting resin, and radiation-curable resin used for the relief layer are not particularly limited, but for example, fluorine-based resins, polyester-based resins such as PET and PEN, (meth)acrylic resins, polyolefin-based resins such as polyethylene and polypropylene, thermoplastic elastomers, polycarbonate, polyamide, ABS resin, acrylonitrile-styrene resin, polystyrene, vinyl chloride, resins having a urethane bond, etc. can be used. Among them, from the viewpoint of impact resistance, etc., a resin having a urethane bond is preferable. The relief layer may contain at least one of the pigments used in the color layer.

[0062] The thickness of the decorative layer may be appropriately adjusted according to the required decorativeness and the like, and is not particularly limited. Such thickness can be, for example, about 1 micrometer or more, about 3 micrometers or more, or about 5 micrometers or more, and can be about 200 micrometers or less, about 150 micrometers or less, or about 100 micrometers or less.

[0063] The decorative sheet of the present disclosure may include any additional configuration. Examples of such additional configuration can include at least one selected from the group consisting of a surface layer, a bonding layer, and an intermediate film layer. The additional configuration can be applied to the entire surface or a part of the decorative sheet.

[0064] In some embodiments, the decorative sheet of the present disclosure includes a surface layer. The material of the surface layer is not particularly limited. For example, it can include (meth)acrylic resins including polymethyl methacrylate (PMMA) and (meth)acrylic copolymers, resins having urethane bonds (such as polyurethane), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), methyl methacrylate-vinylidene fluoride copolymer (PMMA / PVDF), fluorine resins such as tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV), silicone resins, polyvinyl chloride (PVC), polycarbonate (PC), polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides such as nylon, copolymers such as ethylene / acrylic acid copolymer (EAA) and its ionomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer (EVOH), which can be used alone or blended in two or more kinds. The surface layer may have a single-layer structure or a multilayer structure. For example, the surface layer may be a laminate of films formed from the above resins, or may be a multilayer coating of the above resins. The surface layer may have a three-dimensional uneven shape such as an emboss pattern on the entire surface or a part of its surface.

[0065] The surface layer can be formed by coating a resin composition on the decorative layer directly or via an adhesive layer or the like. Coating of the surface layer can be carried out before or after applying the decorative sheet to the adherend. Alternatively, a surface layer film can be formed by coating a resin composition on a release liner, and the film can be laminated on the decorative layer directly or via an adhesive layer or the like. The surface layer film can be formed, for example, by coating a resin material such as a curable (meth)acrylic resin composition or a reactive polyurethane composition on a release liner or the like by knife coating, bar coating, blade coating, doctor coating, roll coating, cast coating, etc., and curing with light or heating as necessary.

[0066] As the surface layer, one pre-formed into a film shape by extrusion, stretching, etc. may be used. Such a film can be laminated on the decorative layer directly or via an adhesive layer or the like. By using a film with high flatness as such a film, an article (laminate) can be given an appearance with higher surface flatness. The surface layer can also be formed by co-extruding with other layers. As the other layer, for example, a (meth)acrylic film can be used. As the (meth)acrylic film, for example, a resin containing polymethyl methacrylate (PMMA), butyl acrylate, (meth)acrylic copolymer, ethylene / acrylic copolymer, ethylene vinyl acetate / acrylic copolymer, etc. can be formed into a film and used. The (meth)acrylic film is excellent in transparency and / or scratch resistance, is resistant to heat and / or light, and is less likely to cause discoloration and / or gloss change. In addition, it has excellent moldability without using a plasticizer, and is also excellent in stain resistance because it does not require the use of a plasticizer. Among them, those having PMMA as the main component are preferred. For example, when a (meth)acrylic resin excellent in scratch resistance or the like is used as the other layer and a fluororesin such as ETFE, PVDF, PMMA / PVDF, etc. excellent in chemical resistance or the like is used as the surface layer, the formed surface layer can have the performance of both layers.

[0067] The surface layer may be transparent, or may be partially translucent or opaque. From the viewpoint of visibility of the decorative layer and the like, the surface layer is preferably transparent.

[0068] The thickness of the surface layer may vary. For example, it may be about 1 micrometer or more, about 5 micrometers or more, about 10 micrometers or more, about 20 micrometers or more, or about 30 micrometers or more, and may also be about 200 micrometers or less, less than about 200 micrometers, about 180 micrometers or less, about 150 micrometers or less, about 130 micrometers or less, about 100 micrometers or less, or about 80 micrometers or less.

[0069] For the decorative sheet of the present disclosure, a bonding layer (which may also be called a "primer layer" or the like) can be used to bond the respective layers constituting the decorative sheet.

[0070] The bonding layer may include, for example, a resin having a urethane bond, a (meth)acrylic resin, an epoxy resin, or a phenoxy resin, or a blend of two or more of these resins.

[0071] The thickness of the bonding layer can be about 0.1 micrometer or more, about 0.2 micrometer or more, or about 0.5 micrometer or more, and about 10 micrometers or less, less than about 10 micrometers, about 5.0 micrometers or less, about 2.0 micrometers or less, about 1.0 micrometers or less, about 0.5 micrometers or less, or less than about 0.5 micrometer.

[0072] The decorative sheet may optionally include an intermediate film layer, for example, interposed between the surface layer and the decorative layer, or between the decorative layer and the adhesive layer. The intermediate film layer can enhance the strength of the decorative sheet.

[0073] As the intermediate film layer, for example, a resin having a urethane bond, polyolefins such as polyvinyl chloride, polyethylene, and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, a (meth)acrylic polymer, or a resin film of a fluorine-based polymer can be used. The intermediate film layer preferably has thermoplasticity.

[0074] The thickness of the intermediate film layer can be about 5.0 micrometers or more, about 10 micrometers or more, or about 15 micrometers or more, and about 200 micrometers or less, about 100 micrometers or less, or about 50 micrometers or less.

[0075] Each layer constituting the decorative sheet can contain, as optional components, for example, a filler, an antioxidant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a hard coat material, a gloss imparting agent, a dispersant, a plasticizer, a flow improver, a surfactant, a leveling agent, a silane coupling agent, a catalyst, a pigment, a dye, etc., within a range that does not adversely affect the effects of the present invention. The optional components can be used alone or in combination of two or more.

[0076] There is no particular limitation on the method of applying the above-described laminate including the decorative sheet disposed via the adhesive layer on the release layer of the release liner. In some embodiments, such an application method includes: (1) cutting the release liner with a cutter to form a cut portion over at least a part of the length direction of the release liner in the laminate; (2) peeling off at least a part of the release liner over the cut portion to expose the adhesive layer; and (3) applying the exposed adhesive layer to the support member. Here, the "length direction of the release liner in the laminate" does not refer to the thickness direction of the release liner, but can be any direction on the surface of the release liner, for example, the length direction (long side direction) or the width direction (short side direction) of the release liner. The release liner of the present disclosure can reduce or suppress the generation of paper dust, etc. when cut, and can reduce or suppress the resulting appearance defects, and thus can preferably respond to such an application method.

[0077] As a cutter for cutting the release liner, for example, a cutter for the release liner can be used. Examples of the cutter for the release liner include a backsheet cutter. Such a cutter for the release liner generally has a configuration in which the liner is cut at the middle part of the cutter and then the liner is spread at the tip part of the cutter. Therefore, if the cutting edge of the cutter at the middle part becomes dull and the cutting is insufficient, it is considered that the paper is likely to be torn by the tip part of the cutter and paper dust is likely to be generated. The release liner of the present disclosure can reduce or suppress the generation of paper dust and the like even when such a cutter for the release liner is used.

[0078] The release liner of the present disclosure can be evaluated in terms of the generation condition of paper dust and the like by a release liner cutting test described later. In such a test, the size of paper dust and the like is classified into Group 1 (1.0 mm 2 or more) and Group 2 (0.5 mm 2 or more and less than 1.0 mm 2 according to the foreign matter measurement chart of JIS P8208. In some embodiments, the release liner of the present disclosure can suppress the generation of paper dust and the like in Group 1 when such a test is performed. That is, the number of Group 1 can be achieved as 0. Paper dust of the size of Group 1 is likely to cause, for example, a defective appearance of the decorative sheet, but the release liner of the present disclosure can suppress paper dust and the like of such a size. In some embodiments, the release liner of the present disclosure can make the number of Group 2 10 or less, 8 or less, 5 or less, or 4 or less. There is no particular limitation on the lower limit value of such a number, but it can be 0 or more. Paper dust of the size of Group 2 has less influence on, for example, the defective appearance of the decorative sheet compared to paper dust of the size of Group 1, but the less such size of paper dust, the better the appearance can be presented.

[0079] There are no particular restrictions on the material of the support member to which the decorative sheet can be applied. Examples of such materials include resin materials (e.g., polyolefin resin, polyester resin, (meth)acrylic resin, polycarbonate resin, acrylonitrile-butadiene-styrene copolymer), inorganic materials (e.g., glass, ceramic, concrete, gypsum, calcium silicate, natural stone, asphalt), rubber materials, cloth materials (e.g., woven fabric, knitted fabric, non-woven fabric), metal or metal alloy materials (e.g., iron, aluminum, stainless steel), and woody materials including paper, etc.

[0080] There are no particular restrictions on the shape or configuration of the support member. For example, it may have a planar shape (e.g., film shape, plate shape), a curved surface shape, an irregular shape, or a three-dimensional shape, and may be a single-layer configuration, a laminated configuration, or a composite configuration in which a plurality of members with different shapes or materials are combined.

[0081] The laminate including the decorative sheet can be used for various applications. Examples of such applications include signboards (e.g., internally illuminated signboards and externally illuminated signboards); signs (e.g., internally illuminated signs and externally illuminated signs); various interior or exterior decorations, for example, interior or exterior decorations of vehicles such as automobiles, railways, airplanes, and ships (e.g., roof members, pillar members, door trim members, instrument panel members, front members such as bonnets, bumper members, fender members, side sill members, and interior panel members), and interior or exterior decorations of buildings (e.g., window glass, doors, sashes, roof members such as tiles, exterior wall members, wallpapers, etc.); electrical appliances such as personal computers, smartphones, mobile phones, refrigerators, and air conditioners; stationery; furniture; desks; various containers such as cans, etc.

Examples

[0082] In the following examples, specific embodiments of the present disclosure are illustrated, but the present invention is not limited thereto. All parts and percentages are by mass unless otherwise specified. The numerical values include errors essentially caused by the measurement principle and measurement apparatus. The numerical values are shown as significant figures with normal rounding.

[0083] Examples 1 to 3 and Comparative Examples 1 to 3 〈Example 1〉 On both sides of a paper base material having a basis weight of about 70 g / m 2 containing about 40% by mass of recycled pulp, after applying a polyethylene resin layer with a thickness of about 20 micrometers by extrusion coating, a silicone-based release layer with a thickness of about 1 micrometer was applied to one of the polyethylene resin layers by gravure coating, and a release liner with a total thickness of about 126 micrometers and a basis weight of about 109 g / m 2 was produced.

[0084] 〈Examples 2 to 3 and Comparative Examples 1 to 3〉 Except that the content of recycled pulp in the paper base material, the basis weight of the paper base material, and the thickness of the polyethylene resin layer were adjusted to change the total thickness and basis weight of the release liner as shown in Table 1, the release liners of Examples 2 to 3 and Comparative Examples 1 to 3 were each produced in the same manner as in Example 1.

[0085] 〈Physical Property Evaluation Test〉 The characteristics of the release liner and the content of inorganic particles in the paper base material were evaluated by conducting the following tests. The results are shown in Table 1.

[0086] (Internal Bond Strength Test of Release Liner) Based on JIS K 6854-2, the internal bond strength of the release liner was measured. The specific measurement method is shown below: A release liner was cut out to a size of 150 mm in length and 25 mm in width to prepare a test piece. From one resin layer of this test piece, a cut was made in the lateral direction such that the blade of the cutter reached near the middle in the thickness direction of the paper substrate. The respective resin layers and the cut paper substrate were pulled in a direction of approximately 180 degrees from the cut position to prepare a T-shaped test piece. The ends of the respective resin layers and the cut paper substrate in the test piece were set in the chuck part of a tensile testing machine (AGS-1kNG, manufactured by Shimadzu Corporation) as shown in Fig. 5(a). In an environment of a temperature of 23°C and a humidity of 65%RH, the test piece was pulled at a speed of 300 mm / min, and the average load after peeling by 50 mm was measured. The test was carried out 3 times, and the average value was taken as the internal bond strength of the release liner. The results are shown in Table 1.

[0087] (Test for Confirming Inorganic Particle Content in Paper Substrate) The test piece prepared in the same manner as in the internal bond strength test was cut into a size of about 1 cm square, and the cut test piece with the paper substrate surface facing up was attached to an aluminum sample stage via a general carbon tape. Using an SU3800PlusII scanning electron microscope manufactured by Hitachi High-Technologies Corporation and an Xplore 30 energy dispersive X-ray spectrometer (hereinafter referred to as the "EDS detector") manufactured by Oxford Instruments Japan K.K., focusing was performed under the following conditions, and the surface of the paper substrate was observed. Data processing was analyzed by AZtecLive attached to the EDS detector. Here, in all samples, the magnification of the screen display was fixed at 100 times (measurement range: approximately 1.25 mm × approximately 1.0 mm square), and elemental analysis regarding inorganic particles was performed 30 times for the integration number, and the mass percentage of the elements within the measurement range was determined. The results are shown in Table 1: Measurement Conditions Acceleration voltage: 10 kV Spot intensity: 60 Work distance: 10 mm Vacuum Mode: 30 Pa Sample Treatment: None Objective Movable Aperture: No.1

[0088] (Peel Liner Cutting Test) Paper dust and the like are likely to be generated as the cutting ability of the cutter deteriorates. Therefore, a cutter with poor cutting ability was adopted in this test. Here, the cutting ability of the cutter was measured as follows, and a cutter with a load of about 2.6 N / m when cutting paper was adopted: Paper with a basis weight of about 68 g / m 2 , a plain copy paper (PPC PAPER High White, manufactured by Otsuka Shokai Co., Ltd.) with a thickness of about 92 micrometers, was cut into a size of 10 cm in length and 29 cm in width. As shown in Fig. 4(a), a 10-cm cut was made longitudinally from the center of the 10-cm-wide end. As shown in Fig. 4(b), a plain copy paper and a back paper cutter (guide cutter, manufactured by KLASS Co., Ltd.) were respectively placed on the upper and lower chuck parts of the tensile testing machine. Here, the back paper cutter was arranged at the cut of the prepared plain copy paper so that the plain copy paper could be cut by pulling the cutter, and the cutting direction and the blade of the cutter were in a substantially straight line state. The average load was measured when the cutter was pulled 15 cm at a tensile speed of 300 mm / second in an environment of 23°C and 65% RH humidity. Such measurement was carried out 3 times, and the average value was taken as the load when cutting the paper.

[0089] The above cutter was adopted, and the peel liner cutting test was carried out in the following procedure: A release liner was cut out to a size of 300 mm in length and 210 mm in width to prepare a test piece. Subsequently, 3M (trademark) Dynoc (trademark) Film WG-157 (3M Japan Limited, Minato-ku, Tokyo, Japan), which is a decorative sheet, was cut out to a size of 400 mm in length and 300 mm in width. Then, the release liner of the film was peeled off, and the release-treated surface of the test piece was bonded to the adhesive surface of the film. After pressing the test piece with a squeegee, using a backsheet cutter, the test piece was cut by about 300 mm in the longitudinal direction at a speed of about 600 mm / min. This cutting operation was performed a total of 4 times with the cutting position shifted (i.e., a total of 1,200 mm was cut). After pressing the test piece with a squeegee again, the test piece was removed, and the size of paper powder and the like adhering to the adhesive surface was classified as follows using the miscellaneous matter measurement chart of JIS P8208, and the number of paper powder and the like adhering to the adhesive surface was recorded according to the classification. The results are shown in Table 1: Size of paper powder etc. Group 1: 1.0 mm 2 or more Group 2: 0.5 mm 2 or more and less than 1.0 mm 2 less than

[0090] [Table 1]

[0091] It is obvious to those skilled in the art that the above embodiments and examples can be variously modified without departing from the basic principles of the present invention. Also, it is obvious to those skilled in the art that various improvements and modifications of the present invention can be implemented without departing from the spirit and scope of the present invention. [Explanation of Reference Numerals]

[0092] 100 Release liner 103, 203, 603 Release layer 105, 205, 605 First resin layer 107, 207, 607 Paper substrate 109, 209, 609 Second resin layer 200 Laminate Decorative sheets 201 and 601 Adhesive layers 202 and 602 Cutting portion 610 Support member 611

[0093] Some embodiments of the present disclosure will be described in the following [Item 1]-[Item 9]. [Item 1] A release liner including a release layer, a first resin layer, a paper base material, and a second resin layer in this order, wherein the paper base material contains recycled pulp, and the release liner has an internal bond strength of about 45.0 N / m or more. [Item 2] The release liner according to Item 1, wherein the paper base material contains about 30% by mass or more of recycled pulp. [Item 3] The basis weight of the release liner is about 200 g / m 2 or less. The release liner according to Item 1 or 2. [Item 4] The release liner according to any one of Items 1 to 3, wherein the thickness of the release liner is about 200 micrometers or less. [Item 5] The release liner according to any one of Items 1 to 4, wherein the content of inorganic particles in the paper base material is about 10% by mass or less. [Item 6] The release liner according to any one of Items 1 to 5, which is for a decorative sheet. [Item 7] A laminate including a decorative sheet disposed via an adhesive layer on the release layer of the release liner according to any one of Items 1 to 6. [Item 8] An application method of applying the laminate according to Item 7 to a support member, forming a cutting portion by cutting the release liner with a cutter over at least a part of the length direction of the release liner in the laminate, peeling at least a part of the release liner over the cutting portion to expose the adhesive layer, and Applying the exposed adhesive layer to the support member, A construction method including this. [Item 9] The construction method according to Item 8, wherein the cutter is a cutter for a release liner.

Claims

1. A release liner comprising a release layer, a first resin layer, a paper substrate, and a second resin layer in this order, wherein the paper substrate contains recycled pulp, and the release liner has an internal bond strength of 45.0 N / m or more.

2. The release liner according to claim 1, wherein the paper substrate contains 30% by mass or more of recycled pulp.

3. The basis weight of the release liner is 200 g / m ２ The release liner according to claim 1 or 2, wherein the basis weight is 200 g / m or less.

4. The release liner according to claim 1 or 2, wherein the thickness of the release liner is 200 micrometers or less.

5. The release liner according to claim 1 or 2, wherein the content of inorganic particles in the paper substrate is 10% by mass or less.

6. The release liner according to claim 1 or 2, which is for a decorative sheet.

7. A laminate comprising a decorative sheet disposed on the release layer of the release liner according to claim 1 or 2 via an adhesive layer.

8. An application method of applying the laminate according to claim 7 to a support member, forming a cut portion by cutting the release liner with a cutter over at least a part of the length direction of the release liner in the laminate, peeling off at least a part of the release liner over the cut portion to expose the adhesive layer, and applying the exposed adhesive layer to the support member, including.

9. The application method according to claim 8, wherein the cutter is a cutter for a release liner.

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