Decorative sheet

Abstract

To provide a decorative sheet having excellent low-temperature adhesion and flame retardancy.SOLUTION: There is provided a decorative sheet comprising a base material composed of a material containing polyvinyl chloride and an adhesive layer provided on one surface side of the base material, wherein the adhesive layer contains an emulsion-based adhesive, a flame retardant having a solidification point of 3°C or less and antimony pentoxide. The content rate of the emulsion-based adhesive in the adhesive layer preferably is 50 mass% or more and 95 mass% or less. Further, in the adhesive layer, the content of the flame retardant having a solidification point of 3°C or less preferably is 1 pt.mass or more and 60 pts.mass or less based on 100 pts.mass of the emulsion-based adhesive.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorative sheet. [Background technology]

[0002] Decorative sheets generally have a structure in which a pressure-sensitive adhesive layer is provided on a substrate, and the substrate is attached to an adherend so as to cover the surface of the adherend, thereby decorating and protecting the adherend. For example, decorative sheets include those that are attached to the wall surfaces of rooms as interior building materials.

[0003] Materials containing polyvinyl chloride are widely used as the substrate of decorative sheets from the viewpoints of durability, flame retardancy, processability, workability, etc. (see, for example, Patent Document 1).

[0004] Furthermore, while solvent-based adhesives have traditionally been widely used to form adhesive layers on decorative sheets, in recent years, there has been a demand to use emulsion-based adhesives from the standpoint of environmental protection.

[0005] Meanwhile, the Building Standards Act requires that interior building materials must be non-combustible or flame-retardant, and therefore decorative sheets are also required to exhibit a certain level of flame retardancy.

[0006] Furthermore, from the viewpoint of ease of application, adhesives used in decorative sheets are required to exhibit adhesive properties at low and normal temperatures.

[0007] For example, Patent Document 2 discloses a non-flammable decorative sheet containing a pressure-sensitive adhesive layer containing a (meth)acrylic acid ester copolymer, a bromine-based flame retardant, antimony trioxide, a tackifier, and a polyisocyanate-based curing agent.

[0008] However, Patent Document 2 does not consider adhesive performance at low temperatures, and there is a demand for decorative sheets that are excellent in low-temperature adhesiveness and flame retardancy. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2022-099752 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-229327 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a decorative sheet that has excellent low-temperature adhesion and flame retardancy. [Means for solving the problem]

[0011] These objects can be achieved by the present invention as set forth in (1) to (6) below. (1) A decorative sheet comprising a substrate made of a material containing polyvinyl chloride and a pressure-sensitive adhesive layer provided on one side of the substrate, The decorative sheet is characterized in that the adhesive layer contains an emulsion-based adhesive, a flame retardant having a solidifying point of 3°C or less, and antimony pentoxide.

[0012] (2) The decorative sheet according to (1) above, wherein the content of the emulsion-based pressure-sensitive adhesive in the pressure-sensitive adhesive layer is 50% by mass or more and 95% by mass or less.

[0013] (3) A decorative sheet according to (1) or (2) above, wherein in the adhesive layer, the content of the flame retardant having a freezing point of 3°C or less per 100 parts by mass of the emulsion-based adhesive is 1 part by mass or more and 60 parts by mass or less.

[0014] (4) A decorative sheet according to any one of (1) to (3) above, wherein the content of the antimony pentoxide in the pressure-sensitive adhesive layer is 1 part by mass or more and 30 parts by mass or less per 100 parts by mass of the emulsion-based pressure-sensitive adhesive.

[0015] (5) A decorative sheet according to any one of (1) to (4) above, wherein the content of the flame retardant having a freezing point of 3°C or less in the pressure-sensitive adhesive layer is X1 [mass%] and the content of the antimony pentoxide is X2 [mass%], and the relationship of 0.1≦X2 / X1≦5.0 is satisfied.

[0016] (6) A decorative sheet according to any one of (1) to (5) above, wherein the adhesive layer has a flame retardant content of 3°C or less of X1 (% by mass), an antimony pentoxide content of X2 (% by mass), and an emulsion adhesive content of X3 (% by mass), satisfying the relationship 0.05≦(X1+X2) / X3≦0.9. [Effects of the Invention]

[0017] According to the present invention, a decorative sheet having excellent low-temperature adhesion and flame retardancy can be provided. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic longitudinal sectional view showing a preferred embodiment of the decorative sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described in detail below. [1] Decorative sheet First, the decorative sheet of the present invention will be described.

[0020] FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the decorative sheet of the present invention. The decorative sheet 1 comprises a substrate 10 made of a material containing polyvinyl chloride, and an adhesive layer 20 provided on one side of the substrate 10. The adhesive layer 20 contains an emulsion-based adhesive, a flame retardant with a freezing point of 3°C or less, and antimony pentoxide.

[0021] The decorative sheet 1 is applied so as to cover at least a portion of the surface of the adherend, and decorates and protects the surface of the adherend. In this specification, the term "sheet" includes the concept of film.

[0022] According to the decorative sheet 1, the base material 10 is made of a material containing polyvinyl chloride, which improves the flame retardancy, water resistance, weather resistance, strength, durability, processability, workability, etc. of the base material 10.

[0023] Furthermore, according to the decorative sheet 1, the adhesive layer 20 contains an emulsion-based adhesive, which can improve the adhesion of the adhesive layer 20 to the substrate 10 containing polyvinyl chloride.

[0024] In this specification, the emulsion-based adhesive refers to an emulsion in which a water-insoluble adhesive (adhesive polymer compound) is dispersed in the form of fine particles in an aqueous solvent.

[0025] Furthermore, the pressure-sensitive adhesive layer 20 contains a flame retardant, which can improve the flame retardancy of the decorative sheet 1.

[0026] In particular, by containing antimony pentoxide and a flame retardant with a freezing point of 3°C or lower in the adhesive layer 20, the decorative sheet 1 as a whole has sufficiently excellent flame retardancy, while the freezing of the flame retardant at low temperatures is suppressed, so that the adhesive layer 20 does not have an impeded adhesive property at low temperatures, resulting in excellent low-temperature adhesiveness.

[0027] In this specification, low temperature refers to a temperature in a cold environment, ie, a temperature of 10°C or lower.

[0028] Furthermore, according to the decorative sheet 1, the adhesive layer 20 contains antimony pentoxide (Sb2O5), which reduces the total heat generated when the adhesive layer 20 burns, and imparts high flame retardancy to the adhesive layer 20 without impairing the adhesive properties of the adhesive layer 20. This provides the decorative sheet 1 with excellent low-temperature adhesion and flame retardancy.

[0029] Furthermore, the decorative sheet 1 uses an emulsion-based adhesive, which is a non-solvent adhesive, as the adhesive, which not only reduces the amount of volatile organic compounds (VOCs) emitted during the production of the decorative sheet 1, but also reduces the amount of residual solvent in the product after production.

[0030] [1-1] Base material The substrate 10 is a sheet-like member, and as described above, is made of a material containing polyvinyl chloride.

[0031] Polyvinyl chloride has higher flame retardancy than other resin materials, and is also excellent in water resistance and weather resistance, and its strength and plasticity can be easily adjusted by adding a plasticizer or the like.

[0032] Therefore, by using polyvinyl chloride to form the substrate 10, the flame retardancy, water resistance, weather resistance, strength, durability, processability, workability, and the like of the substrate 10 can be easily improved.

[0033] The substrate 10 may contain other resin materials in addition to polyvinyl chloride. Furthermore, the material that constitutes the substrate 10 may contain various additives as needed.

[0034] Examples of additives include plasticizers, stabilizers, and colorants. Examples of the plasticizer that can be used include phthalate ester plasticizers such as octyl phthalate (di-2-ethylhexyl phthalate (DOP)), dibutyl phthalate, dinonyl phthalate, and diisononyl phthalate (DINP); aliphatic dibasic acid diester plasticizers such as dioctyl adipate and dioctyl sebacate; phosphate ester plasticizers such as tricresyl phosphate and trioctyl phosphate; epoxy plasticizers such as epoxidized soybean oil and epoxy resin; and polyester plasticizers.

[0035] Examples of the stabilizer that can be used include metal soaps such as fatty acid calcium, fatty acid zinc, and fatty acid barium; hydrotalcite; epoxy-based stabilizers; barium-based stabilizers; calcium-based stabilizers; tin-based stabilizers; zinc-based stabilizers; and composite stabilizers such as calcium-zinc (Ca-Zn) and barium-zinc (Ba-Zn) systems. Specific examples of the metal soaps include calcium laurate, calcium stearate, calcium ricinoleate, zinc laurate, zinc ricinoleate, zinc stearate, barium laurate, barium stearate, and barium ricinoleate. As the colorant, for example, organic pigments, inorganic pigments, dyes, etc. can be used.

[0036] The substrate 10 only needs to be made of a material containing polyvinyl chloride at least in the area that comes into contact with the pressure-sensitive adhesive layer 20, and may have an area that does not contain polyvinyl chloride.

[0037] The polyvinyl chloride content in the portion of the substrate 10 that comes into contact with the adhesive layer 20 is preferably 50% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 93% by mass or less, and even more preferably 60% by mass or more and 90% by mass or less.

[0038] If the polyvinyl chloride content is too low, the strength, rigidity, flame retardancy, etc. of the substrate 10 may decrease. If the polyvinyl chloride content is too high, the strength and rigidity of the substrate 10 may become too high, which may decrease processability and workability.

[0039] The substrate 10 may have a printed layer formed thereon to form a decoration. The printed layer may be formed, for example, inside the substrate 10, or may be laminated on the surface opposite to the surface that comes into contact with the pressure-sensitive adhesive layer 20. Furthermore, a coating layer that protects the surface of the substrate 10 may be provided on the surface of the substrate 10 opposite to the surface that comes into contact with the pressure-sensitive adhesive layer 20, either on top of the printed layer or instead of the printed layer. Another layer may be laminated on the surface of the substrate 10 opposite to the surface that comes into contact with the pressure-sensitive adhesive layer 20.

[0040] The thickness of the substrate 10 is preferably 100 μm or more and 300 μm or less, more preferably 130 μm or more and 250 μm or less, and even more preferably 150 μm or more and 200 μm or less. This makes the decorative sheet 1 particularly easy to handle.

[0041] [1-2] Adhesive layer The pressure-sensitive adhesive layer 20 is the portion that comes into contact with and bonds to the adherend when the decorative sheet 1 is attached to the adherend.

[0042] As described above, the adhesive layer 20 contains an emulsion-based adhesive, a flame retardant having a solidifying point of 3° C. or less, and antimony pentoxide.

[0043] [1-2-1] Emulsion-based adhesive An emulsion-based pressure-sensitive adhesive is a pressure-sensitive adhesive formed using a pressure-sensitive adhesive composition that is an emulsion containing a pressure-sensitive adhesive component or its precursor as a dispersoid. Usually, the emulsion-based pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer 20 itself contains almost no dispersion medium component of the pressure-sensitive adhesive composition, and even if it contains a dispersion medium component of the pressure-sensitive adhesive composition, the component does not function as a dispersion medium.

[0044] The pressure-sensitive adhesive composition is preferably an aqueous emulsion containing an acrylic copolymer.

[0045] The emulsion-based pressure-sensitive adhesive can be obtained, for example, by emulsion polymerization of a monomer mixture containing a (meth)acrylic acid alkyl ester containing an alkyl group having from 4 to 12 carbon atoms, a carboxyl group-containing unsaturated monomer, a carbonyl group-containing unsaturated monomer, and, if necessary, other unsaturated monomers. In this specification, the term "(meth)acrylic acid" encompasses both "acrylic acid" and "methacrylic acid." The same applies to "(meth)acrylate," "(meth)acrylo," and "(meth)allyl," which will be described later.

[0046] The (meth)acrylic acid alkyl ester containing an alkyl group having 4 to 12 carbon atoms is not particularly limited, and examples thereof include n-butyl(meth)acrylate, isobutyl(meth)acrylate, n-hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, benzyl(meth)acrylate, cyclohexyl(meth)acrylate, isooctyl(meth)acrylate, n-octyl(meth)acrylate, nonyl(meth)acrylate, isononyl(meth)acrylate, decyl(meth)acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate, isoundecyl(meth)acrylate, dodecyl(meth)acrylate, and isododecyl(meth)acrylate. Of these, n-butyl(meth)acrylate and 2-ethylhexyl acrylate are preferably used, and one or more selected from these may be used in combination.

[0047] The carboxyl group-containing unsaturated monomer is not particularly limited, but examples thereof include acrylic acid, acrylic acid dimer, methacrylic acid, crotonic acid, itaconic acid, maleic acid, etc., and one or more selected from these may be used in combination. Among these, acrylic acid, methacrylic acid, etc. are preferably used.

[0048] The carbonyl group-containing unsaturated monomer is not particularly limited, but examples thereof include diacetone acrylamide, 2-(acetoacetoxy)ethyl (meth)acrylate, and allyl acetoacetate, and one or more selected from these may be used in combination. Among these, diacetone acrylamide is preferably used.

[0049] Furthermore, other unsaturated monomers are not particularly limited, but examples thereof include (meth)acrylic acid alkyl esters having an alkyl group of 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate; (meth)acrylic acid alkyl esters having an alkyl group of 13 or more carbon atoms, such as tridecyl (meth)acrylate, isotridecyl (meth)acrylate, and tetradecyl (meth)acrylate; dimethylaminoethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl chloride, and alkyl vinyl ethers.

[0050] In addition to the above, the unsaturated monomer may also be a functional group-containing unsaturated monomer, such as a hydroxyl group-containing unsaturated monomer, an epoxy group-containing unsaturated monomer, an alkoxysilyl group-containing unsaturated monomer, an amide group- or methylol group-containing unsaturated monomer, or a polyfunctional unsaturated monomer.

[0051] Examples of the hydroxyl group-containing unsaturated monomer include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0052] Examples of the epoxy group-containing unsaturated monomer include glycidyl (meth)acrylate and allyl glycidyl ether.

[0053] Examples of the alkoxysilyl group-containing unsaturated monomer include (meth)acryloxyethyltrimethoxysilane, (meth)acryloxyethyltriethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropyldimethylethoxysilane, γ-(meth)acryloxypropyltrichlorosilane, γ-(meth)acryloxypropylmethyldichlorosilane, γ-(meth)acryloxypropyldimethylchlorosilane, and γ-(meth)acryloxypropyltripropyloxysilane. , γ-(meth)acryloxypropylmethyldipropoxysilane, γ-(meth)acryloxypropyltributoxysilane, (meth)acryloxybutyltrimethoxysilane, (meth)acryloxypentyltrimethoxysilane, (meth)acryloxyhexyltrimethoxysilane, (meth)acryloxyhexyltriethoxysilane, (meth)acryloxyoctyltrimethoxysilane, (meth)acryloxydecyltrimethoxysilane, (meth)acryloxydodecyltrimethoxysilane, (meth)acryloxyoctadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriporopoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldipropoxysilane, and the like.

[0054] Examples of unsaturated monomers containing an amide group or a methylol group include acrylamide, methacrylamide, N-methylolacrylamide, and butoxy N-methylolacrylamide.

[0055] Examples of the polyfunctional unsaturated monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexyl Examples of the acrylates include sandiol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, glycerin methacrylate acrylate, tris(meth)acryloyloxyphosphate, glycerin di(meth)acrylate, diallyl terephthalate, tetraallyloxyethane, divinylbenzene, and tri(meth)allyl isocyanurate.

[0056] The content of the emulsion-based adhesive in the adhesive layer 20 is preferably 50% by mass or more and 95% by mass or less, more preferably 60% by mass or more and 90% by mass or less, and even more preferably 65% ​​by mass or more and 85% by mass or less.

[0057] This allows the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10, the adhesiveness of the decorative sheet 1 to the adherend, and the flame retardancy of the decorative sheet 1 to be improved.

[0058] In contrast, if the content of emulsion-based pressure-sensitive adhesive in the pressure-sensitive adhesive layer 20 is less than the above-mentioned lower limit, there is a possibility that the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 and the adhesion of the decorative sheet 1 to the adherend will decrease. On the other hand, if the content of emulsion-based pressure-sensitive adhesive in the pressure-sensitive adhesive layer 20 exceeds the above-mentioned upper limit, there is a possibility that the content of flame retardant in the pressure-sensitive adhesive layer 20 will decrease, making it difficult to improve the flame retardancy of the decorative sheet 1.

[0059] The average particle size of the emulsion-based pressure-sensitive adhesive in the pressure-sensitive adhesive layer 20 is preferably 80 nm or more and 1000 nm or less, more preferably 200 nm or more and 800 nm or less, and even more preferably 300 nm or more and 600 nm or less.

[0060] This allows for better removability of the decorative sheet 1, while also improving the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 and the adhesiveness of the decorative sheet 1 to the adherend.

[0061] In contrast, if the average particle size of the emulsion-based pressure-sensitive adhesive is less than the above-mentioned lower limit, the adhesiveness of the pressure-sensitive adhesive layer 20 to the adherend will be too high, and there is a possibility that part of the pressure-sensitive adhesive layer 20 will remain on the adherend when the decorative sheet 1 is peeled from the adherend. On the other hand, if the average particle size of the emulsion-based pressure-sensitive adhesive exceeds the above-mentioned upper limit, there is a possibility that the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10 will decrease, or that the adhesiveness of the decorative sheet 1 to the adherend will decrease. In this specification, the term "average particle size" refers to the average particle size on a volume basis.

[0062] [1-2-2] Flame retardants with a freezing point of 3°C or less As described above, the adhesive layer 20 contains a flame retardant, and is made of a "flame retardant mixed adhesive" in which a flame retardant is mixed with an emulsion-based adhesive.

[0063] This can improve the flame retardancy of the pressure-sensitive adhesive layer 20, and can improve the flame retardancy of the entire decorative sheet 1.

[0064] In particular, the pressure-sensitive adhesive layer 20 contains a flame retardant having a solidifying point of 3° C. or less, as described above. This prevents the flame retardant from solidifying even at low temperatures, thereby providing excellent low-temperature adhesiveness to the adhesive layer 20. Furthermore, workability at low temperatures can be improved.

[0065] The freezing point of the flame retardant may be 3°C or lower, preferably -10°C or lower, more preferably -15°C or lower, and even more preferably -20°C or lower.

[0066] This allows the adhesive layer 20 to have excellent adhesiveness even in a lower temperature environment, such as below freezing point.

[0067] Examples of flame retardants having a freezing point of 3°C or less include non-halogen phosphate ester flame retardants, non-halogen condensed phosphate ester flame retardants, halogen-containing phosphate ester flame retardants, halogen-containing condensed phosphate ester flame retardants, and the like, and one or more selected from these may be used in combination.

[0068] Commercially available non-halogen phosphate ester flame retardants with a freezing point of 3°C or less include, for example, "TCP (tricresyl phosphate)" (freezing point: -20°C or less), "TXP (trixylenyl phosphate)" (freezing point: -15°C), "CDP (cresyl diphenyl phosphate)" (freezing point: -30°C), and "PX-110 (cresyl di-2,6-xylenyl phosphate)" (freezing point: -14°C), all manufactured by Daihachi Chemical Industry Co., Ltd.

[0069] An example of a commercially available non-halogen condensed phosphate ester flame retardant with a freezing point of 3°C or less is "CR-733S (aromatic condensed phosphate ester)" (freezing point: -13°C) manufactured by Daihachi Chemical Industry Co., Ltd.

[0070] An example of a commercially available halogen-containing phosphate ester flame retardant having a freezing point of 3° C. or less is "TMCPP (tris(chloropropyl)phosphate)" (freezing point: -40° C.) manufactured by Daihachi Chemical Industry Co., Ltd.

[0071] Commercially available halogen-containing condensed phosphate ester flame retardants with a freezing point of 3°C or less include, for example, "CR-504L" (freezing point: less than -100°C) and "CR-570" (freezing point: -20°C or less) manufactured by Daihachi Chemical Industry Co., Ltd.

[0072] Phosphorus-based flame retardants exhibit flame retardancy by producing phosphoric acid, polyphosphoric acid, etc. during combustion, which extract hydrogen and oxygen from the polymer, carbonizing the polymer and forming a highly flame-retardant carbonized film that blocks oxygen.

[0073] Furthermore, halogen-containing flame retardants exhibit flame retardancy by trapping active radicals generated during combustion, reducing the amount of heat generated by preferentially generating carbon monoxide, and providing a masking effect due to non-flammable gases such as halogen gases, thereby improving the flame retardancy of the pressure-sensitive adhesive layer 20 and the decorative sheet 1 as a whole.

[0074] In particular, when the halogen-containing flame retardant is a bromine-containing flame retardant, the above-mentioned effects are more pronounced.

[0075] It is particularly preferable that the pressure-sensitive adhesive layer 20 contains a halogen-containing phosphorus-based flame retardant as a flame retardant having a solidifying point of 3° C. or less.

[0076] This allows the effects of the halogen-based flame retardant and the phosphorus-based flame retardant to be exerted synergistically, thereby improving the low-temperature adhesion of the adhesive layer 20 while also improving the flame retardancy of the decorative sheet 1.

[0077] In the adhesive layer 20, the content of the flame retardant with a freezing point of 3°C or less per 100 parts by mass of emulsion-based adhesive is preferably 1 part by mass or more and 60 parts by mass or less, more preferably 3 parts by mass or more and 50 parts by mass or less, and even more preferably 5 parts by mass or more and 40 parts by mass or less.

[0078] This allows the adhesive layer 20 to have better adhesion to the substrate 10 and the adherend, while also providing the decorative sheet 1 with better flame retardancy and low-temperature adhesiveness.

[0079] In contrast, if the content of the flame retardant with a freezing point of 3°C or below in the emulsion-based pressure-sensitive adhesive is too low, the amount of flame retardant with a freezing point of 3°C or below contained in the pressure-sensitive adhesive layer 20 will be too small, making it difficult to improve the flame retardancy and low-temperature adhesiveness of the decorative sheet 1. On the other hand, if the content of the flame retardant with a freezing point of 3°C or below in the emulsion-based pressure-sensitive adhesive is too high, the amount of flame retardant with a freezing point of 3°C or below contained in the pressure-sensitive adhesive layer 20 will be too high, which will affect the adhesive properties of the pressure-sensitive adhesive layer 20 and may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend.

[0080] The average particle size of the flame retardant contained in the adhesive layer 20 and having a freezing point of 3°C or less is preferably 50 nm or more and 1000 nm or less, more preferably 100 nm or more and 800 nm or less, and even more preferably 150 nm or more and 600 nm or less.

[0081] This allows the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend, and the flame retardancy of the decorative sheet 1 to be improved.

[0082] In contrast, if the average particle size of the flame retardant having a freezing point of 3°C or less is less than the lower limit, the flame retardancy of the flame retardant may be difficult to exhibit. On the other hand, if the average particle size of the flame retardant having a freezing point of 3°C or less exceeds the upper limit, the flame retardant may be too large, which may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend.

[0083] The flame retardant having a solidification point of 3° C. or less contained in the adhesive layer 20 is preferably emulsified.

[0084] By emulsifying a flame retardant with a freezing point of 3°C or less, it is possible to, for example, more effectively prevent the flame retardant from forming secondary aggregates and settling in the pressure-sensitive adhesive layer 20, and to increase the affinity between the emulsion-based pressure-sensitive adhesive and the flame retardant. As a result, it is possible to more effectively prevent a decrease in the adhesiveness of the pressure-sensitive adhesive layer 20, while also improving the flame retardancy of the decorative sheet 1.

[0085] [1-2-3]Antimony pentoxide As described above, the adhesive layer 20 contains antimony pentoxide (Sb2O5).

[0086] In the pressure-sensitive adhesive layer 20, by using antimony pentoxide, which has a low calorific value, in addition to a flame retardant with a freezing point of 3°C or less, it is possible to reduce the total calorific value when the pressure-sensitive adhesive layer 20 burns. This improves the flame retardancy of the pressure-sensitive adhesive layer 20, making the flame retardancy of the entire decorative sheet 1 particularly excellent.

[0087] Furthermore, antimony pentoxide does not impair the transparency of the pressure-sensitive adhesive layer 20 containing antimony pentoxide.

[0088] The average particle size of the antimony pentoxide contained in the pressure-sensitive adhesive layer 20 is preferably 10 nm or more and 100 nm or less, more preferably 15 nm or more and 80 nm or less, and even more preferably 20 nm or more and 50 nm or less.

[0089] This allows the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend, and the flame retardancy of the decorative sheet 1 to be improved.

[0090] On the other hand, if the average particle size of antimony pentoxide is less than the lower limit, the flame retardancy of antimony pentoxide may be difficult to exhibit. On the other hand, if the average particle size of antimony pentoxide exceeds the upper limit, the antimony pentoxide particles may be too large, which may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend.

[0091] The content of antimony pentoxide in the adhesive layer 20 is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 3 parts by mass or more and 25 parts by mass or less, and even more preferably 5 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of emulsion-based adhesive.

[0092] This allows the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10 and the adherend to be improved, while also improving the flame retardancy of the decorative sheet 1.

[0093] In contrast, if the content of antimony pentoxide relative to the emulsion-based adhesive is too low, the amount of antimony pentoxide contained in the adhesive layer 20 will be too small, making it difficult to improve the flame retardancy of the decorative sheet 1. On the other hand, if the content of antimony pentoxide relative to the emulsion-based adhesive is too high, the amount of antimony pentoxide contained in the adhesive layer 20 will be too high, which will affect the adhesive properties of the adhesive layer 20 and may reduce the adhesion of the adhesive layer 20 to the substrate 10 or the adherend.

[0094] When the content of the flame retardant having a freezing point of 3°C or less in the adhesive layer 20 is X1 [mass%] and the content of antimony pentoxide is X2 [mass%], it is preferable to satisfy the relationship 0.1≦X2 / X1≦5.0, it is more preferable to satisfy the relationship 0.2≦X2 / X1≦3.0, and it is even more preferable to satisfy the relationship 0.3≦X2 / X1≦2.0.

[0095] By satisfying this relationship, the effect of using a flame retardant with a freezing point of 3°C or less in combination with antimony pentoxide is more pronounced, and the low-temperature adhesion of the adhesive layer 20 and the flame retardancy of the decorative sheet 1 can be achieved at a higher level.

[0096] In the adhesive layer 20, the sum of the content of the flame retardant having a freezing point of 3°C or less and the content of antimony pentoxide is preferably 5% by mass or more and 45% by mass or less, more preferably 8% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less.

[0097] This allows the adhesive layer 20 to have better adhesion to the substrate 10 and the adherend, and the decorative sheet 1 to have better low-temperature adhesion and flame retardancy.

[0098] In contrast, if the total content of flame retardants with a freezing point of 3°C or below and antimony pentoxide in the pressure-sensitive adhesive layer 20 is below the aforementioned lower limit, the amount of flame retardants with a freezing point of 3°C or below and antimony pentoxide contained in the pressure-sensitive adhesive layer 20 will be too small, making it difficult to improve the flame retardancy and low-temperature adhesiveness of the decorative sheet 1. On the other hand, if the total content of flame retardants with a freezing point of 3°C or below and antimony pentoxide in the pressure-sensitive adhesive layer 20 exceeds the aforementioned upper limit, the amount of flame retardants with a freezing point of 3°C or below and antimony pentoxide contained in the pressure-sensitive adhesive layer 20 will be too high, which will affect the adhesive properties of the pressure-sensitive adhesive layer 20 and may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or adherend.

[0099] [1-2-4] Relationship between emulsion adhesive and flame retardant in adhesive layer When the content of the flame retardant having a freezing point of 3°C or less in the adhesive layer 20 is X1 [mass %], the content of antimony pentoxide is X2 [mass %], and the content of the emulsion-based adhesive is X3 [mass %], it is preferable to satisfy the relationship 0.05≦(X1+X2) / X3≦0.9, it is more preferable to satisfy the relationship 0.08≦(X1+X2) / X3≦0.8, and it is even more preferable to satisfy the relationship 0.1≦(X1+X2) / X3≦0.6.

[0100] This allows the adhesive layer 20 to have better adhesion to the substrate 10 and the adherend, and the decorative sheet 1 to have better low-temperature adhesion and flame retardancy.

[0101] In contrast, if (X1+X2) / X3 is less than the lower limit, the content of flame retardant with a freezing point of 3°C or less and antimony pentoxide will be reduced, making it difficult to improve the low-temperature adhesiveness and flame retardancy of the decorative sheet 1. On the other hand, if (X1+X2) / X3 exceeds the upper limit, the content of emulsion-based adhesive will be reduced, which may reduce the adhesion of the adhesive layer 20 to the adherend.

[0102] When the average particle diameter of the emulsion-based adhesive contained in the adhesive layer 20 is D1 [nm] and the average particle diameter of the flame retardant contained in the adhesive layer 20 and having a freezing point of 3°C or less is D2 [nm], it is preferable to satisfy the relationship 0.1≦D2 / D1≦0.9, it is more preferable to satisfy the relationship 0.2≦D2 / D1≦0.8, and it is even more preferable to satisfy the relationship 0.3≦D2 / D1≦0.7.

[0103] This allows the adhesive layer 20 to have better adhesion to the substrate 10 and the adherend, and the decorative sheet 1 to have better low-temperature adhesion and flame retardancy.

[0104] On the other hand, if D2 / D1 is less than the lower limit, the average particle size of the flame retardant with a freezing point of 3°C or less will be too small, which may make it difficult to improve the flame retardancy and low-temperature adhesiveness of the decorative sheet 1. If D2 / D1 exceeds the upper limit, the average particle size of the flame retardant with a freezing point of 3°C or less will be too large, which may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend.

[0105] When the average particle diameter of the emulsion-based adhesive contained in the adhesive layer 20 is D1 [nm] and the average particle diameter of the antimony pentoxide contained in the adhesive layer 20 is D3 [nm], it is preferable to satisfy the relationship 0.1≦D3 / D1≦0.9, it is more preferable to satisfy the relationship 0.2≦D3 / D1≦0.8, and it is even more preferable to satisfy the relationship 0.3≦D3 / D1≦0.7.

[0106] This allows the adhesiveness of the pressure-sensitive adhesive layer 20 to the substrate 10 or the adherend, and the flame retardancy of the decorative sheet 1 to be improved.

[0107] On the other hand, if D3 / D1 is less than the lower limit, the average particle size of antimony pentoxide will be too small, which may make it difficult to improve the flame retardancy of the decorative sheet 1. If D3 / D1 exceeds the upper limit, the average particle size of antimony pentoxide will be too large, which may reduce the adhesion of the pressure-sensitive adhesive layer 20 to the substrate 10 or adherend.

[0108] [1-2-5] Other ingredients In addition to the components described above, the pressure-sensitive adhesive layer 20 may further contain other components as needed.

[0109] Examples of other components include flame retardants other than those mentioned above (for example, flame retardants with a freezing point exceeding 3°C), dispersants, antioxidants, polymerization initiators, ultraviolet absorbers, light stabilizers, heat stabilizers, softeners, silane coupling agents, fillers, colorants, antistatic agents, etc., and one or more selected from these may be used in combination.

[0110] However, the content of other components in the pressure-sensitive adhesive layer 20 is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0111] [1-2-6] Other conditions The thickness of the pressure-sensitive adhesive layer 20 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0112] This allows the decorative sheet 1 to exhibit better adhesive strength to the adherend, and also improves workability when applying the decorative sheet 1 to the adherend.

[0113] [1-3] Release liner The surface of the pressure-sensitive adhesive layer 20 of an unused decorative sheet 1 is preferably covered with a release liner 30, as shown in FIG.

[0114] This makes it possible to suitably protect the pressure-sensitive adhesive layer 20 before it is attached to the adherend, and also makes it easier to handle an unused decorative sheet 1.

[0115] The release liner 30 has releasability relative to the pressure-sensitive adhesive layer 20. The release liner 30 functions to protect the pressure-sensitive adhesive layer 20 at least during storage of the decorative sheet 1. When the decorative sheet 1 is attached to an adherend, the release liner 30 is in a state where it has been peeled off from the pressure-sensitive adhesive layer 20.

[0116] Examples of materials constituting the release liner 30 include paper, various plastics such as polyesters such as polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, and metals, and one or more selected from these may be used in combination.

[0117] The release liner 30 may be subjected to a release treatment. Examples of release agents used for the release treatment include silicone, olefin-based resins, isoprene-based resins, butadiene-based resins, long-chain alkyl-based resins, and alkyd-based resins.

[0118] The thickness of the release liner 30 is not particularly limited, but is preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 140 μm or less.

[0119] [1-4] How to use decorative sheets The decorative sheet 1 is preferably used by being attached to interior walls, floors, ceilings, etc. of a building.The decorative sheet 1 is preferably used by being attached to gypsum board used for interior walls, floors, ceilings, etc. of a building.

[0120] According to the decorative sheet 1, the adhesive layer 20 contains an emulsion adhesive, a flame retardant with a freezing point of 3°C or less, and antimony pentoxide, thereby providing a decorative sheet with excellent low-temperature adhesion and flame retardancy.

[0121] In the decorative sheet 1, the flame retardant with a freezing point of 3°C or less contained in the adhesive layer 20 is mixed with antimony pentoxide, suppressing heat generation when the adhesive layer 20 burns, thereby enabling the sheet to exhibit excellent flame retardancy.

[0122] Furthermore, in the decorative sheet 1, the adhesive layer 20 contains a flame retardant with a freezing point of 3°C or less, so the flame retardant does not solidify even at low temperatures and is able to exhibit excellent adhesiveness, thereby providing the decorative sheet 1 with excellent workability at low temperatures.

[0123] [2] Manufacturing method of decorative sheet The decorative sheet 1 may be manufactured by any method, but can be suitably manufactured, for example, by a method comprising a first step of manufacturing a flame-retardant mixed adhesive by mixing an emulsion-based adhesive with a flame retardant, a second step of applying the flame-retardant mixed adhesive to the substrate 10, and a third step of curing the flame-retardant mixed adhesive applied to the substrate 10.

[0124] [2-1] First step In the first step, a flame-retardant mixed adhesive is produced by mixing an emulsion-based adhesive, a flame retardant having a freezing point of 3°C or less, and antimony pentoxide. At this time, the flame retardant having a freezing point of 3°C or less can be added and mixed in an emulsified state or in a state dispersed in a dispersing medium such as water. Also, antimony pentoxide can be added and mixed in a state dispersed in a dispersing medium such as water.

[0125] [2-2] Second step In the second step, a flame retardant mixed adhesive is applied to one surface of the substrate 10 to form an adhesive layer 20 .

[0126] This step can be carried out, for example, by applying a flame retardant mixed adhesive to the surface of the substrate 10 .

[0127] In addition, this process can be suitably carried out, for example, by applying a flame-retardant mixed adhesive onto a release liner 30, drying it for a predetermined time, and then transferring the flame-retardant mixed adhesive applied to the release liner 30 to one side of the substrate 10.

[0128] By the method described above, the adhesive layer 20 can be formed on the surface of the substrate 10, and the decorative sheet 1 can be obtained.

[0129] In this embodiment, by using a non-solvent emulsion-based adhesive as the adhesive, it is possible to reduce the amount of volatile organic compounds (VOCs) emitted during the production of decorative sheets, as well as the amount of residual solvent in the product after production.

[0130] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0131] For example, the decorative sheet of the present invention may further comprise components other than those described above. For example, the decorative sheet of the present invention may comprise a coating layer (e.g., a coating layer for printing) or an intermediate layer.

[0132] Furthermore, the decorative sheet of the present invention may be produced by any method, and is not limited to the methods described in the above-mentioned embodiments. More specifically, for example, the decorative sheet of the present invention may be produced using a method that omits the third step described above. [Example]

[0133] The present invention will be described in detail below based on specific examples, but the present invention is not limited thereto. Treatments and measurements in the following examples, for which no temperature conditions are specified, were carried out at room temperature (23°C).

[0134] [3] Manufacturing of decorative sheets Example 1 (1) Manufacturing of substrate First, a molten composition containing the following components in proportions: 100.0 parts by mass of polyvinyl chloride, 20.0 parts by mass of dioctyl phthalate, 5.0 parts by mass of epoxy plasticizer, 2.0 parts by mass of barium zinc stabilizer, and 10.0 parts by mass of titanium oxide (pigment) was formed into a film having a thickness of 160 μm using a calendar roll to obtain a substrate.

[0135] (2) Manufacturing of flame retardant mixed adhesives To 100.0 parts by mass (solids) of an acrylic resin emulsion adhesive (Diabond DW3124 manufactured by Nogawa Chemical Co., Ltd., solids content 55.5% by mass), 9.0 parts by mass (solids) of a flame retardant with a freezing point of 3°C or less (CR-570 (halogen-containing condensed phosphate ester) manufactured by Daihachi Chemical Industry Co., Ltd., solids content 100% by mass (freezing point: -20°C or less)) and 17.3 parts by mass (solids) of antimony pentoxide (NYACOL A1550 manufactured by Nyacol, water dispersion with solids content of 48% by mass, average particle size 30 nm) were added and mixed to obtain a flame-retardant mixed adhesive.

[0136] (3) Manufacture of decorative sheets The resulting flame retardant-mixed adhesive was applied to a previously prepared release liner so that the adhesive layer would be 50 μm thick after drying, and then dried at 100°C for 1 minute. The adhesive layer was then transferred to a substrate and allowed to stand at 23°C and 50% RH for 7 days to obtain a decorative sheet.

[0137] In this example, the content X1 of the flame retardant having a freezing point of 3°C or less in the adhesive layer was 7.1 mass%, the content X2 of antimony pentoxide was 13.7 mass%, and the content X3 of the emulsion-based adhesive was 79.2 mass%.

[0138] Examples 2 to 12 A decorative sheet was produced in the same manner as in Example 1, except that in the production of the flame retardant mixed adhesive, the blending amounts of the flame retardant with a freezing point of 3°C or less and antimony pentoxide were changed as shown in Table 1.

[0139] (Comparative Example 1) A decorative sheet was produced in the same manner as in Example 1, except that in the production of the flame retardant mixed adhesive, neither a flame retardant with a solidifying point of 3° C. or less nor antimony pentoxide was added.

[0140] (Comparative Example 2) In the production of the flame retardant mixed adhesive, 18.0 parts by mass (solids) of "CR-741 (bisphenol A bis(diphenyl phosphate)), 100% solids by mass" (freezing point: 4°C to 5°C) manufactured by Daihachi Chemical Industry Co., Ltd. was used instead of "CR-570," a flame retardant with a freezing point of 3°C or less, and antimony pentoxide was not added. A decorative sheet was produced in the same manner as in Example 1.

[0141] (Comparative Examples 3 to 5) A decorative sheet was produced in the same manner as in Example 1, except that in the production of the flame retardant mixed adhesive, antimony pentoxide was not added and the amount of flame retardant with a freezing point of 3°C or less was changed as shown in Table 2.

[0142] (Comparative Examples 6 to 8) A decorative sheet was produced in the same manner as in Example 1, except that in the production of the flame retardant mixed adhesive, no flame retardant with a freezing point of 3°C or less was added and the amount of antimony pentoxide added was changed as shown in Table 2.

[0143] [4] Evaluation The decorative sheets of the above-mentioned Examples and Comparative Examples were evaluated as follows.

[0144] [4-1] Adhesive strength after 24 hours The decorative sheets of each of the examples and comparative examples were cut to 25 mm x 300 mm and used as test pieces for measuring adhesive strength. In accordance with JIS Z0237:2022, the test pieces were attached to stainless steel test plates (test plates) while pressing them using a 2 kg roller, and left for 24 hours in an environment of 23°C and 50% RH or an environment of 5°C and 50% RH. Thereafter, under the same conditions as when they were left, the adhesive strength was measured by a test method in which the test piece was peeled off at an angle of 180° from the test plate at a peel rate of 300 mm / min.

[0145] [4-2] Pyrogenicity test Each decorative sheet (cut into 100 mm square) obtained in each of the Examples and Comparative Examples was layered on a 12.5 mm thick non-combustible certified gypsum board (with base paper attached to both surfaces) cut into a 100 mm square to form a laminate, which was used as a test specimen. The produced test specimen was left in an environment of 23°C and 50% RH for at least one week before being used in the following tests.

[0146] The test piece was subjected to a cone calorimeter (manufactured by Fire Testing Technology Ltd) in accordance with ISO 5660-1:2002 cone calorimeter method, with the radiant heat condition on the test piece surface being 50kW / m 2 A heat generation test was conducted, measuring the heat generation rate. Here, the test piece surface (the side to which radiant heat is applied) refers to the decorative sheet surface of the test piece. In this way, the total heat generation rate of the test piece over a 20-minute test period was determined and evaluated according to the following criteria. The smaller the total heat generation rate, the better the flame retardancy.

[0147] A: Total calorific value is 7.2 [MJ / m 2 ] is less than. B: Total calorific value is 7.2 [MJ / m 2 ] or more 8.0[MJ / m 2 ] is less than. C: Total calorific value is 8.0 [MJ / m 2 ]That's all. These results are summarized in Tables 1 and 2.

[0148] [Table 1]

[0149] [Table 2]

[0150] As is clear from Tables 1 and 2, excellent results were obtained with the decorative sheet of the present invention. It was also confirmed that the decorative sheet of the present invention has sufficient low-temperature adhesion and flame retardancy. In contrast, the comparative examples did not provide satisfactory results. [Explanation of symbols]

[0151] 1...Decorative sheet 10...Base material 20...Adhesive layer 30...Release liner

Claims

1. A decorative sheet comprising a substrate made of a material containing polyvinyl chloride and a pressure-sensitive adhesive layer provided on one surface of the substrate, The decorative sheet is characterized in that the adhesive layer contains an emulsion-based adhesive, a flame retardant having a solidification point of 3°C or less, and antimony pentoxide.

2. The decorative sheet according to claim 1 , wherein the content of the emulsion-based pressure-sensitive adhesive in the pressure-sensitive adhesive layer is 50% by mass or more and 95% by mass or less.

3. 3. The decorative sheet according to claim 1, wherein the content of the flame retardant having a freezing point of 3°C or less in the pressure-sensitive adhesive layer is 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of the emulsion-based pressure-sensitive adhesive.

4. 3. The decorative sheet according to claim 1, wherein the content of the antimony pentoxide in the pressure-sensitive adhesive layer is 1 part by mass or more and 30 parts by mass or less per 100 parts by mass of the emulsion-based pressure-sensitive adhesive.

5. 3. The decorative sheet according to claim 1 or 2, wherein the content of the flame retardant having a freezing point of 3°C or less in the pressure-sensitive adhesive layer is X1 [mass%], and the content of the antimony pentoxide is X2 [mass%], the relationship of 0.1≦X2 / X1≦5.0 is satisfied.

6. 3. The decorative sheet according to claim 1 or 2, wherein the content of the flame retardant having a freezing point of 3°C or less in the pressure-sensitive adhesive layer is X1 [% by mass], the content of the antimony pentoxide is X2 [% by mass], and the content of the emulsion-based pressure-sensitive adhesive is X3 [% by mass], and the relationship of 0.05≦(X1+X2) / X3≦0.9 is satisfied.

Images