Hot melt adhesive composition and laminate having adhesive layer made using the same

Abstract

The object of the present invention is to provide a hot melt pressure sensitive adhesive composition that has good coatability and high adhesive strength, holding power and ball tack, and a laminate using the same. [Solution] The aforementioned problems are solved by a hot-melt pressure-sensitive adhesive composition comprising a styrene-based block copolymer (A), a tackifying resin (B), a mineral oil (C), a wax (D), and polybutene (E), wherein the content of polybutene (E) is less than 5 mass% relative to 100 mass% of the hot-melt pressure-sensitive adhesive composition, the composition having a melt viscosity (η1) at 160°C of 25,000 mPa·s or less, a melt viscosity (η2) at 180°C of 15,000 mPa·s or less, and a ratio (η1 / η2) of the melt viscosity (η1) at 160°C to the melt viscosity (η2) at 180°C of 1.0 to 2.5.

Description

[Technical Field]

[0001] The present invention relates to a hot melt pressure-sensitive adhesive composition and a laminate including a pressure-sensitive adhesive layer formed using the hot melt pressure-sensitive adhesive composition. [Background technology]

[0002] In the field of building materials, decorative panels obtained by laminating decorative sheets having decorative colors or patterns onto plywood have been widely used for the purpose of improving aesthetics and imparting durability. Hot-melt adhesives or reactive hot-melt adhesives are used to bond decorative panels, and they are required to not only provide strong adhesion but also be easy to apply and durable for long-term use.

[0003] Conventionally, various proposals have been made for hot melt adhesives used in decorative sheets, such as those shown in Patent Documents 1 to 3 below.

[0004] Patent Document 1 describes a laminated board with excellent heat resistance that uses a polyurethane reactive hot melt adhesive and a non-reactive hot melt adhesive in combination. However, the non-reactive hot melt adhesive disclosed in Patent Document 1 has a high melting temperature, which results in high viscosity during application, making it difficult to smooth the coated surface, and it has low ball tack (initial tack), which means that it does not adhere well unless pressed.

[0005] The hot melt adhesive disclosed in Patent Document 2 has good applicability and exhibits sufficient adhesiveness after being heated, bonded, and cooled, but has the problem of insufficient holding power at 40°C.

[0006] The hot melt adhesive disclosed in Patent Document 3 has sufficient adhesive properties after being applied and cured, but it takes time to cure, and there is a problem that if it is used before curing, it does not exhibit sufficient adhesive strength and holding power. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-228311 [Patent Document 2] Japanese Patent Publication No. 2020-203447 [Patent Document 3] Japanese Patent Publication No. 2020-97650 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a hot melt pressure sensitive adhesive composition that has good coatability and high adhesive strength, holding power and ball tack, and a laminate using the same. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, an embodiment of the present invention is a hot melt pressure-sensitive adhesive composition comprising a styrene block copolymer (A), a tackifier resin (B), a mineral oil (C), a wax (D), and a polybutene (E), wherein the content of the polybutene (E) is less than 5% by mass relative to 100% by mass of the hot melt pressure-sensitive adhesive composition; The present invention relates to a hot melt pressure-sensitive adhesive composition characterized in that the melt viscosity (η1) at 160°C is 25,000 mPa·s or less, the melt viscosity (η2) at 180°C is 15,000 mPa·s or less, and the ratio (η1 / η2) of the melt viscosity (η1) at 160°C to the melt viscosity (η2) at 180°C is 1.0 to 2.5.

[0010] The hot melt pressure-sensitive adhesive composition is characterized in that it contains 50% by mass or more of a styrene-isoprene-styrene block copolymer in 100% by mass of the styrene block copolymer (A).

[0011] The hot melt pressure-sensitive adhesive composition, wherein the styrene block copolymer (A) comprises a styrene block copolymer (A') that satisfies the following (i) and (ii): (i) Diblock ratio is 10 to 80 mass% (ii) Styrene ratio is 10 to 40 mass%

[0012] The present invention relates to the hot melt pressure-sensitive adhesive composition, wherein the tackifier resin (B) is at least one selected from the group consisting of petroleum-based resins, rosin-based resins, and terpene-based resins.

[0013] The hot melt pressure-sensitive adhesive composition is characterized in that the wax (D) is polyethylene or polypropylene having a melting point of 100°C or higher.

[0014] The present invention relates to a laminate comprising a substrate and a pressure-sensitive adhesive layer made of the hot-melt pressure-sensitive adhesive composition. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a hot melt pressure sensitive adhesive composition that has good coatability and high adhesive strength, holding power and ball tack. DETAILED DESCRIPTION OF THE INVENTION

[0016] The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, unless otherwise specified, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the range of the lower and upper limits.

[0017] The hot melt pressure sensitive adhesive composition of the present invention will be described in detail below.

[0018] <Styrene-based block copolymer (A)> The styrene-based block copolymer (A) refers to a block polymer having at least one segment (hereinafter also referred to as "segment X") made of a polymer containing 50% by mass or more of styrene and at least one segment (hereinafter also referred to as "segment Y") made of a polymer containing 50% by mass or more of a conjugated diene compound. Representative structures of block copolymers include a triblock copolymer (XYX structure) having segment X at each end of segment Y, and a diblock copolymer (XY structure) made of one segment X and one segment Y. The block copolymer (A) may be in the form of a diblock copolymer, a triblock copolymer, a radial copolymer, a mixture thereof, or the like.

[0019] Examples of the styrene-based block copolymer (A) include styrene-butadiene-styrene block copolymer (hereinafter also abbreviated as "SBS"), hydrogenated styrene-butadiene-styrene block copolymer (hereinafter also abbreviated as "SEBS"), styrene-isoprene-styrene block copolymer (hereinafter also abbreviated as "SIS"), hydrogenated styrene-isoprene-styrene block copolymer (hereinafter also abbreviated as "SEPS"), styrene-butadiene-isoprene-styrene block copolymer (hereinafter also abbreviated as "SBIS"), and hydrogenated styrene-butadiene-isoprene-styrene block copolymer (hereinafter also abbreviated as "SEEPS"). The styrene-based block copolymer (A) may be carboxyl-modified, hydroxyl-modified, epoxy-modified, amino-modified, urethane-modified, or thiol-modified. Furthermore, the segment X in the styrene-based block copolymer (A) may contain a copolymer of styrene and another aromatic vinyl compound such as α-methylstyrene. Among the modified copolymers, carboxyl-modified copolymers are preferred from the viewpoint of increasing adhesive strength.

[0020] The styrene-isoprene-styrene block copolymer is preferably contained in an amount of 50% by mass or more, more preferably 55% by mass or more, based on 100% by mass of the styrene-based block copolymer (A). By containing 50% by mass or more of the styrene-isoprene-styrene block copolymer, sufficient adhesive strength can be exhibited.

[0021] The styrene block copolymer (A) preferably contains a styrene block copolymer (A') that satisfies the following (i) and (ii): (i) Diblock ratio is 10 to 80 mass% (ii) Styrene ratio is 10 to 40 mass% By including the styrene-based block copolymer (A'), cohesive strength can be exerted, resulting in better adhesive strength.

[0022] The diblock ratio is more preferably 12 to 78% by mass. The "diblock ratio" refers to the mass proportion of the diblock in the total mass of each styrene-based block copolymer. When the styrene-based block copolymer (A) contains two or more types of styrene-based block copolymers with different diblock ratios, it is preferable that the diblock ratio of each styrene-based block copolymer be within the above range. The styrene ratio is more preferably 13 to 37% by mass. The "styrene ratio" refers to the mass proportion of the styrene component in the total mass of each styrene block copolymer. When the styrene block copolymer (A) contains two or more types of styrene block copolymers with different styrene ratios, it is preferable that the styrene ratio of each styrene block copolymer be within the above range.

[0023] The content of the styrene block copolymer (A') in the styrene block copolymer (A) is preferably as high as possible in terms of adhesive strength, and is preferably 70% by mass or more, more preferably 75% by mass or more, and most preferably 80% by mass or more.

[0024] The content of the styrene block copolymer (A) in 100% by mass of the hot melt pressure-sensitive adhesive composition is preferably 30 to 45% by mass, and more preferably 35 to 40% by mass. When the content of the styrene block copolymer is 30% by mass or more, the adhesive strength of the resulting hot melt pressure-sensitive adhesive composition is good. When the content of the styrene block copolymer is 45% by mass or less, kneading during production can be easily performed. The styrene block copolymer (A) may be used alone or in combination of two or more types.

[0025] <Tackifying resin (B)> The tackifying resin (B) can be appropriately selected from known resins. Examples include phenolic resins, xylene resins, coumarone-indene resins, petroleum-based resins, rosin-based resins, and terpene-based resins. From the viewpoint of compatibility, it is preferable to contain at least one resin selected from the group consisting of petroleum-based resins, rosin-based resins, and terpene-based resins. From the viewpoint of increasing adhesive strength, it is more preferable to contain a petroleum-based resin.

[0026] Examples of petroleum-based resins include phenolic resins, modified phenolic resins, xylene phenolic resins, xylene resins, cyclopentadiene-phenolic resins, aliphatic, alicyclic, and aromatic petroleum resins, hydrogenated aliphatic, alicyclic, and aromatic petroleum resins, phenol-modified petroleum resins, and low-molecular-weight polystyrene resins. Examples of rosin-based resins include natural rosin and esters of the natural rosin, rosin ester resins, and hydrogenated rosin ester resins. Examples of terpene-based resins include terpene resins, hydrogenated terpene resins, terpene phenolic resins, and aromatic-modified terpene resins.

[0027] The softening point of the tackifier resin (B) of the present invention is preferably 80 to 150° C., more preferably 85 to 145° C. When the softening point of the tackifier resin is 80° C. or higher, cohesive strength is exerted and adhesive strength is good, and when the softening point of the tackifier resin is 150° C. or lower, adhesive strength is easily exerted sufficiently. The method for measuring the softening point is described in detail in the Examples.

[0028] The content of the tackifier resin (B) in 100% by mass of the hot melt pressure-sensitive adhesive composition is preferably 30 to 55% by mass, more preferably 32 to 53% by mass. When the content of the tackifier resin (B) is 30% by mass or more, processability is easily maintained. When the content of the tackifier resin (B) is 55% by mass or less, a sufficient balance between adhesive strength and tackiness can be maintained. The tackifier resin (B) may be used alone or in combination of two or more types.

[0029] <Mineral oil (C)> The mineral oil (C) is not particularly limited, and examples thereof include paraffinic mineral oil, naphthenic mineral oil, and aromatic mineral oil. In general, mineral oils are classified as follows: those in which the number of carbon atoms in the paraffin chain is 50% or more of the total number of carbon atoms, those in which the number of carbon atoms in the naphthenic ring is 35 to 45% of the total number of carbon atoms are called paraffinic mineral oils, and those in which the number of aromatic carbon atoms is 30% or more of the total number of carbon atoms are called naphthenic mineral oils. As the mineral oil (C), paraffinic mineral oils are preferred from the viewpoint of hue.

[0030] The hot melt pressure-sensitive adhesive composition of the present invention may contain oils other than the mineral oil (C). Examples of oils other than the mineral oil (C) include vegetable oils such as rice bran oil, safflower oil, and corn oil.

[0031] The content of the mineral oil (C) in 100% by mass of the hot melt pressure-sensitive adhesive composition is preferably 5 to 25% by mass, and more preferably 7 to 23% by mass. When the content of the mineral oil (C) is 5% by mass or more, processability is improved, and when the content of the mineral oil (C) is 25% by mass or less, cohesive strength is exerted and adhesive strength is improved. The mineral oil (C) may be used alone or in combination of two or more types.

[0032] <Wax (D)> The wax (D) is not particularly limited, and examples thereof include paraffin wax, microcrystalline wax, montan wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, polyethylene-polypropylene wax, polyethylene, low-molecular-weight polyethylene, polypropylene, low-molecular-weight polypropylene, low-molecular-weight ethylene-propylene copolymer, oxide of low-molecular-weight ethylene-propylene copolymer, low-molecular-weight ethylene-butene copolymer, low-molecular-weight propylene-butene-ethylene copolymer, styrene-grafted low-molecular-weight ethylene-propylene copolymer, maleic anhydride oxide of ethylene-propylene copolymer, and modified wax such as maleic anhydride oxide of propylene-butene-ethylene copolymer. As the wax (D), polyethylene and polypropylene are preferred because they exert cohesive force and provide good adhesive strength.

[0033] The melting point of the wax (D) is preferably 100° C. to 150° C., more preferably 102 to 148° C. In the present invention, the melting point is the peak top temperature when the temperature is increased at a rate of 10° C. / min in differential scanning calorimetry.

[0034] The content of wax (D) in 100% by mass of the hot melt pressure-sensitive adhesive composition is preferably 0.1 to 8% by mass, more preferably 0.5 to 7.5% by mass. When the content of wax (D) is 0.1% by mass or more, cohesive strength is exerted and adhesive strength is good. When the content of wax (D) is 8% by mass or less, appropriate adhesive strength can be exhibited. Wax (D) may be used alone or in combination of two or more types.

[0035] <Polybutene (E)> Polybutene (E) has a kinematic viscosity (JIS K2283) of 50 to 5,000 mm at 100°C. 2 / sec, and more preferably 60 to 4,980 mm 2 / sec, more preferably 70 to 4,950 mm 2 / sec. The kinematic viscosity of polybutene (E) at 100°C is 50mm 2 / sec or more, adhesive strength and holding power are fully exerted, and 2 / sec or less, tackiness can be maintained. The kinematic viscosity of polybutene (E) is a value measured at 100°C in accordance with JIS K2283.

[0036] The content of polybutene (E) in 100% by mass of the hot melt pressure-sensitive adhesive composition is less than 5% by mass. It is preferably 0.1% by mass or more but less than 5% by mass, more preferably 0.3% by mass or more but less than 4.8% by mass, and even more preferably 0.5% by mass or more but less than 4.5% by mass. By including polybutene (E) in the above range, initial tackiness and holding power can be imparted. The polybutene (E) may be used alone or in combination of two or more kinds.

[0037] The hot melt pressure-sensitive adhesive composition of the present invention may contain additives such as antioxidants, ultraviolet absorbers, antibacterial agents, deodorants, insect repellents, silane coupling agents, colorants, adhesion inhibitors, light stabilizers, fillers, and fragrances, as long as the addition does not impair the object of the invention.

[0038] Examples of the antioxidant include pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-t-butyl-4-hydroxy-m-tolyl]propionate, tris(2,4-di-t-butylphenyl)phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, etc. These antioxidants may be used alone or in combination of two or more.

[0039] The above-mentioned phenolic antioxidants function as radical traps, donating hydrogen to ROO· (peroxy radicals) generated during the chain growth process of autoxidation to stabilize them, and then converting them into stable phenoxy radicals protected by ortho-substituents to terminate the chain reaction, thereby effectively suppressing thermal degradation of hot-melt pressure-sensitive adhesive compositions. In particular, the combined use of phenolic antioxidants with lactone-based antioxidants or vitamin E-based antioxidants, which have faster radical trapping reactions than phenolic antioxidants, provides even more effective results. Furthermore, the above-mentioned phosphorus-based antioxidants non-radical decompose peroxides and ROOH, thereby terminating the chain reaction of the autoxidation process, thereby effectively suppressing thermal degradation of hot-melt pressure-sensitive adhesive compositions.

[0040] The ultraviolet absorber is not particularly limited, and examples thereof include commonly used ones such as salicylic acid-based, benzophenone-based, benzotriazole-based, etc. These ultraviolet absorbers may be used alone or in combination of two or more.

[0041] Examples of the antibacterial agent include benzylamine antibacterial agents such as butenafine and its salts, imidazole antibacterial agents such as bifonazole, neticonazole, ketoconazole, lanoconazole, clotrimazole, miconazole, oxiconazole, tioconazole, cloconazole, omoconazole, sulconazole and their salts, allylamine antibacterial agents such as terbinafine and its salts, morpholine antibacterial agents such as amorolfine and its salts, thiocarbamic acid antibacterial agents such as liranafte, tolnaftate and tolciclate, and antibiotics such as nystatin, trichomycin, variotin, siccanin and pyrrolnitrin. These antibacterial agents may be used alone or in combination of two or more.

[0042] The deodorant is not particularly limited as long as it has a deodorizing effect, and examples thereof include lauryl methacrylate, geranyl chlorinate, citronellyl senecionate, terpene aldehydes, pyruvate esters, zinc 2-ethylhexanoate, zinc ricinoleate, etc. These deodorants may be used alone or in combination of two or more.

[0043] Examples of the insect repellent include camphor, naphthalene, paradichlorobenzene, isobornyl, thiocyanoacetic acid, 1,2-benzenedicarboxylic acid diethyl ester, paraform, chloropicrin, pyrethrum, empenthrin, transfluthrin, allethrin, phenothrin, eminence, etc. These insect repellents may be used alone or in combination of two or more.

[0044] The silane coupling agent is not particularly limited, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethylmethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, etc. These silane coupling agents may be used alone or in combination of at least two types.

[0045] The colorant may be any commonly used colorant, including inorganic pigments and organic pigments. Examples of inorganic pigments include carbon black, iron oxide, titanium oxide, zinc oxide, red iron oxide, cadmium red, cadmium yellow, ultramarine, cobalt blue, titanium yellow, white lead, red lead, lead yellow, and iron blue. Examples of organic pigments include quinacridone, polyazo yellow, anthraquinone yellow, polyazo red, azo lake yellow, perylene, phthalocyanine green, phthalocyanine blue, and isoindolinone yellow. These colorants may be used alone or in combination of at least two types.

[0046] Examples of the adhesion inhibitor include fatty acid amides, long-chain alkyl grafted polyethyleneimine, soybean oil-modified alkyd resins (e.g., Arakawa Chemical Industries, Ltd., trade name "Arakid 251"), tall oil-modified alkyd resins (e.g., Arakawa Chemical Industries, Ltd., trade name "Arakid 6300"), etc. These adhesion inhibitors may be used alone or in combination of at least two types.

[0047] Examples of the light stabilizer include commonly used hindered amine-based stabilizers.

[0048] Examples of the filler include talc, clay, glass beads, calcium silicate, silica, zeolite, diatomaceous earth, alumina, titanium oxide, iron oxide, zinc oxide, magnesium oxide, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, calcium carbonate, magnesium carbonate, synthetic organic fibers, natural fibers, iron powder, wood flour, etc. These fillers may be used alone or in combination of at least two types.

[0049] Examples of the fragrance include hydrocarbon fragrances such as pinene and limonene, alcohol fragrances such as linalool, geraniol, citronellol, menthol, borneol, benzyl alcohol, anise alcohol, and β-phenethyl alcohol, phenol fragrances such as anethole and eugenol, aldehyde fragrances such as n-butyraldehyde, isobutyraldehyde, hexylaldehyde, citral, citronellal, benzaldehyde, and cinnamic aldehyde, ketone fragrances such as carvone, menthone, camphor, acetophenone, and ionone, lactone fragrances such as γ-butyrolactone, coumarin, and cineol, and ester fragrances such as octyl acetate, benzyl acetate, cinnamyl acetate, butyl propionate, and methyl benzoate. These fragrances may be used alone or in combination of two or more.

[0050] The amount of additives such as antioxidants, UV absorbers, antibacterial agents, deodorants, insect repellents, silane coupling agents, colorants, adhesion inhibitors, light stabilizers, fillers, and fragrances that can be added within a range that does not impair the object of the present invention is preferably 10% by mass or less, more preferably 8% by mass or less, based on 100% by mass of the hot-melt pressure-sensitive adhesive composition. If the amount is 10% by mass or less, bleeding out can be suppressed.

[0051] <Hot melt pressure-sensitive adhesive composition> The hot melt pressure-sensitive adhesive composition of the present invention contains a styrene block copolymer (A), a tackifier resin (B), a mineral oil (C), a wax (D), and a polybutene (E), and has a melt viscosity (η1) at 160°C of 25,000 mPa·s or less, a melt viscosity (η2) at 180°C of 15,000 mPa·s or less, and a ratio (η1 / η2) of the melt viscosity (η1) at 160°C to the melt viscosity (η2) at 180°C of 1.0 to 2.5. The value of (η1 / η2) is preferably 1.2 to 2.3. When the melt viscosity (η1) at 160°C, the melt viscosity (η2) at 180°C, and the ratio (η1 / η2) of the melt viscosity (η1) at 160°C to the melt viscosity (η2) at 180°C satisfy the above ranges, the hot-melt pressure-sensitive adhesive composition of the present invention can be coated at 60 to 200°C, and can be used with rolls that require low-viscosity coating or melting kettles equipped with a stirrer for melting. The melt viscosity of the hot-melt pressure-sensitive adhesive composition is a value measured using a B-type viscometer. Details will be described in the Examples.

[0052] <Method for producing hot melt pressure sensitive adhesive composition> The hot-melt pressure-sensitive adhesive composition according to the present invention can be prepared by uniformly dispersing and mixing the above-mentioned various components in an inert gas atmosphere, and the mixing means and conditions are not particularly limited. Typical preparation methods include kneading the various components using an apparatus such as a mixing roll, a roll, a Banbury mixer, a single- or twin-screw extruder, a kneader, an extruder, a melt extruder, or a heat-melting kettle equipped with a stirrer, followed by cooling and pulverizing the resulting kneaded mixture. The kneading method is also not particularly limited, but heat-melt kneading is preferred. The conditions for heat-melt kneading may be appropriately determined depending on the types and amounts of the various components used, and are not particularly limited.

[0053] In one embodiment of the present invention, the heat-melt kneading is preferably carried out at a temperature range of 60 to 200°C for 15 to 500 minutes, and more preferably at a temperature range of 65 to 190°C for 20 to 490 minutes. When the temperature for heat-melt kneading is 60°C or higher, the various components can be sufficiently heat-melt kneaded and uniformly mixed. On the other hand, when the temperature for heat-melt kneading is 200°C or lower, the hot-melt pressure-sensitive adhesive composition can be kneaded without decomposition or a decrease in viscosity. Furthermore, when the heat-melt kneading time is less than 15 minutes, sufficient heat-melt kneading may not be achieved, and when it is longer than 500 minutes, no further effect is obtained.

[0054] The hot melt pressure-sensitive adhesive composition of the present invention may be in the form of, for example, a block, a strand, a sheet, a flat plate, a pellet, etc. From the viewpoint of production stability, the hot melt pressure-sensitive adhesive composition of the present invention is preferably in the form of a block.

[0055] <Adhesive layer> The hot-melt pressure-sensitive adhesive composition of the present invention can be applied in various patterns, such as a mirror finish, foamed state, beaded state, spiral state, or foam state, to a sheet-like substrate such as paper or resin using a commonly used coater or hot-melt coater, followed by heating and cooling as necessary, to form a pressure-sensitive adhesive layer, and various laminates having pressure-sensitive adhesive layers can be obtained. The hot-melt pressure-sensitive adhesive compositions can be applied in layers, or two different hot-melt pressure-sensitive adhesive compositions can be applied in parallel to the same sheet-like substrate.

[0056] The pressure-sensitive adhesive layer can be formed using a commonly used coating device, such as a roll knife coater, a die coater, a roll coater, a bar coater, a gravure roll coater, a reverse roll coater, a dipping coater, or a blade coater.

[0057] <Laminate> Next, the laminate of the present invention will be described. The basic laminate structure of the laminate of the present invention is a single-sided laminate such as substrate / hot-melt pressure-sensitive adhesive composition layer / release film, or a double-sided laminate such as release film / hot-melt pressure-sensitive adhesive composition layer / substrate / hot-melt pressure-sensitive adhesive composition layer / release film. During use, the release film is peeled off, and the hot-melt pressure-sensitive adhesive composition layer is applied to an adherend. The hot-melt pressure-sensitive adhesive composition of the present invention does not completely solidify during application, and has tack and appropriate hardness, while also possessing cohesive strength to maintain the adhesive state.

[0058] The substrate material can be any material without particular limitations. Examples of resin films include polyester resins, polycarbonate resins, polyarylate resins, acrylic resins, polyphenylene sulfide resins, polystyrene resins, vinyl resins, polyimide resins, epoxy resins, and olefin resins such as polyethylene, polypropylene, and norbornene. The substrate can be a single-layer or multi-layer substrate. Other examples include nonwoven fabrics, woven fabrics, cloth, paper, glass, metal foils such as aluminum, metal mesh, and composites containing these. If necessary, the surface of the substrate may be subjected to adhesion-enhancing treatments such as corona discharge treatment, plasma treatment, blast treatment, and chemical etching, antistatic treatment, and coloring treatment. Furthermore, a release film can also be used as the substrate, and the hot-melt pressure-sensitive adhesive composition can be coated on the release film. The thickness of these substrates is not particularly limited, but a thickness of 5 to 1000 μm is preferred for ease of use.

[0059] The amount of the hot melt adhesive composition applied is 2 to 300 g / m 2 , preferably 3 to 298 g / m 2 , and more preferably 5 to 295 g / m 2 The coating amount is 2 to 300 g / m 2 Within this range, sufficient adhesive strength is exhibited, which is preferable.

[0060] The hot melt pressure-sensitive adhesive composition layer can be used by being attached to a release film, etc., if necessary. The release film is not particularly limited, but examples thereof include polyethylene terephthalate film (hereinafter referred to as PET film), polyolefin resin films such as polyethylene, polypropylene, and norbornene, PPS resin film, TAC film, acrylic resin film, and films thereof that have been subjected to a release treatment.

[0061] The laminate of the present invention may have a configuration in which a hot melt pressure-sensitive adhesive composition layer is sandwiched between a film-like substrate other than a release film and a release film, between a film-like substrate other than a release film and another film-like substrate other than a release film, or between two release films. A configuration in which a hot melt pressure-sensitive adhesive composition layer is sandwiched between a film-like substrate other than a release film and a release film is preferred. [Example]

[0062] The present invention will be described in more detail below with reference to examples, but these examples are merely one embodiment of the present invention and the present invention is not limited to these examples. In the examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively.

[0063] The softening point, melting point, and viscosity at 160°C and 180°C of the hot-melt pressure-sensitive adhesive composition were measured by the following methods.

[0064] <Softening point> The softening point was measured according to the method specified in JIS K 6863. That is, a specified ring filled with a hot-melt pressure-sensitive adhesive composition was left to stand for 12 hours or more, and then placed in a heating medium. A specified ball was placed on the specified ring filled with the hot-melt pressure-sensitive adhesive composition, and the temperature of the heating medium (glycerin) was raised at a certain rate. The temperature at which the ball sank due to softening of the hot-melt pressure-sensitive adhesive composition and touched the bottom plate of the ring stand was read and taken as the softening point.

[0065] <Melting point> The melting point was measured using a differential scanning calorimeter (DSC-60A Plus, manufactured by Shimadzu Corporation). Specifically, approximately 5 mg of the hot-melt pressure-sensitive adhesive composition was weighed on an aluminum pan, the aluminum pan was set in a DSC measurement holder, and the exothermic peak of the chart obtained at a temperature rise rate of 10°C / min was read. The melting point was taken as the temperature at the peak top.

[0066] <Viscosity measurement at 160℃ and 180℃> The viscosity was measured using a B-type viscometer (TVB-10M, manufactured by Toki Sangyo Co., Ltd.) under the following conditions. Temperature: 160℃, 180℃ Sample amount: approx. 500g Rotor No.: 3 Rotor speed: 3 or 6 rpm Spin time: 30 seconds

[0067] Example 1 A kneader equipped with a stirrer was charged with 41 parts of A1 (D1117 manufactured by Kraton Corporation) as a styrene-based block copolymer (A), 20 parts of B5 (Quinton N180 manufactured by Zeon Corporation) and 25 parts of B6 (Haritac FK125 manufactured by Harima Chemicals Co., Ltd.) as tackifying resins (B), 13 parts of C3 (Diana Fresia N90 manufactured by Idemitsu Kosan Co., Ltd.) as a mineral oil (C), 0.5 parts of D1 (Hiwax 200P manufactured by Mitsui Chemicals Co., Ltd.) as a wax (D), 0.5 parts of E2 (HV-100 manufactured by Eneos Materials Co., Ltd.) as a polybutene (E), and 0.5 parts of an antioxidant, and the mixture was stirred at 150°C for 300 minutes to obtain a hot-melt pressure-sensitive adhesive composition.

[0068] (Examples 2 to 11, Comparative Examples 1 to 8) A hot-melt pressure-sensitive adhesive composition was produced in the same manner as in Example 1, except that the materials and blending amounts were changed to those shown in Tables 1 and 2.

[0069] [Table 1]

[0070] [Table 2]

[0071] The materials in Tables 1 and 2 are shown below. A1: SIS, styrene ratio 17% by mass, diblock ratio 33% (product name: D1117, manufactured by Kraton) A2: SIS, styrene ratio 16% by mass, diblock ratio 56% (product name: Quintac 3433N, manufactured by Zeon Corporation) A3: SIS, styrene ratio 15% by mass, diblock ratio 78% (product name: Quintac 3520, manufactured by Zeon Corporation) A4: SBS, styrene ratio 33% by mass, diblock ratio 78% (product name: D1118, manufactured by Kraton) A5: SEPS, styrene ratio 13% by mass, diblock ratio 0% (product name: Septon 2063, manufactured by Kuraray Co., Ltd.)

[0072] B1: Hydrogenated petroleum-based tackifying resin, softening point 100°C (product name: Hi-Tack JH-6100, manufactured by Ningbo Jinhai Chenguang Chemical Corporation) B2: Unhydrogenated petroleum-based tackifier resin, softening point 120℃ (product name: L-120A, manufactured by Shanghai Qilong Chemical Co. Ltd.) B3: Hydrogenated petroleum-based tackifying resin, softening point 115°C (product name: Alcon P-115, manufactured by Arakawa Chemical Industries, Ltd.) B4: Hydrogenated petroleum-based tackifier resin, softening point 140℃ (Product name: Alcon P-140, manufactured by Arakawa Chemical Industry Co., Ltd.) B5: Unhydrogenated alicyclic petroleum hydrocarbon resin, softening point 80°C (product name: Quinton N180, manufactured by Zeon Corporation) B6: Rosin-based tackifying resin, softening point 125°C (product name: Haritack FK125, manufactured by Harima Chemicals Co., Ltd.)

[0073] C1: Paraffinic mineral oil, paraffin chain carbon number of total carbon number: 71%, naphthenic ring carbon number of total carbon number: 29% (product name: Diana Process Oil PW-90, Idemitsu Kosan Co., Ltd.) C2: Paraffinic mineral oil, paraffin chain carbon number of total carbon number: 73%, naphthenic ring carbon number of total carbon number: 27% (product name: Diana Process Oil PW-380, Idemitsu Kosan Co., Ltd.) C3: Naphthenic mineral oil, paraffin chain carbon number of total carbon number: approximately 48%, naphthenic ring carbon number of total carbon number: approximately 46%, aromatic ring carbon number of total carbon number: approximately 6% (product name: Diana Fresia N90, manufactured by Idemitsu Kosan Co., Ltd.)

[0074] D1: Polyethylene wax, melting point 122°C (product name: Hiwax 200P, manufactured by Mitsui Chemicals) D2: Polypropylene wax, melting point 136°C (product name: Viscol 660-P, manufactured by Sanyo Chemical Industries, Ltd.) D3: Paraffin wax, melting point 69°C (product name: Nichirou 155 Para, manufactured by Nippon Seiro)

[0075] E1: Polybutene, kinematic viscosity 3710mm 2 / s (100°C), (Product name: HV-1900, manufactured by Eneos Materials Co., Ltd.) E2: Polybutene, kinematic viscosity 220mm 2 / s (100°C), (Product name: HV-100, manufactured by Eneos Material Co., Ltd.)

[0076] The abbreviations for the other components listed in Tables 1 and 2 are as follows: Antioxidant: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)] UV absorber: 4-tert-butylphenyl salicylate

[0077] (evaluation) The hot-melt pressure-sensitive adhesive compositions prepared in Examples 1 to 11 and Comparative Examples 1 to 8 were evaluated for viscosity, coatability, adhesive strength, holding power, ball tack, and heat resistance at 160°C and 180°C according to the procedures described below. The results are shown in Tables 1 and 2.

[0078] [Melt viscosity] The melt viscosity (η1) at 160°C and the melt viscosity (η2) at 180°C of the hot melt pressure sensitive adhesive composition were measured.

[0079] [Coatability] The hot melt adhesive composition was applied at a coating temperature of 160°C, a coating speed of 20 m / min, and a coating amount of 100 g / m 2 The coating was applied to a 100 μm thick polyethylene terephthalate film so that the width was 30 cm, and the coating properties were evaluated. ◯ and △ were judged to be practical. ◯: Coating was uniform and the coated surface was smooth. △: The coating was uniform, but there were some areas where the coated surface was not smooth. ×: Coating was not uniform and the coated surface was rough.

[0080] [Adhesive strength] The hot melt adhesive composition was applied at a coating temperature of 160°C in an amount of 100 g / m 2 The adhesive sheet sample for evaluation was prepared by applying the coating to a 100 μm thick polyethylene terephthalate film (hereinafter referred to as PET film) so that the adhesive layer was 100 μm thick and then bonding it to a release-treated PET film. The adhesive sheet sample was cut perpendicular to the flow direction into a size of 25 mm wide and 150 mm long to prepare a test sample. The release-treated PET film was peeled off from the test sample, and the test sample was pressed against a cleaned stainless steel plate (SUS304) using a 2 kg rubber roller, which was rolled back and forth at a speed of 300 mm / min. After leaving the sample standing for 24 hours, the sample was peeled off at a 180-degree angle at a speed of 300 mm / min, and the average adhesive strength was calculated. Measurements were conducted in an atmosphere of 23°C and 50% relative humidity. ◯ and △ were judged to be practical. ○:20N / 25mm or more △: 15N / 25mm or more, less than 20N / 25mm ×: Less than 15N / 25mm

[0081] [Holding force] The hot melt adhesive composition was applied at a coating temperature of 160°C in an amount of 100 g / m 2 A 100 μm thick PET film was coated with the adhesive so that the adhesive would be 100 μm thick, and a release-treated PET film was attached to it to prepare a pressure-sensitive adhesive sheet sample for evaluation. The pressure-sensitive adhesive sheet sample was then cut perpendicular to the flow direction into a size of 25 mm wide and 150 mm long to prepare a test sample. The release-treated PET film was peeled off from the test sample, and the test sample was pressed against a cleaned stainless steel plate (SUS304) with a 2 kg rubber roller, moving back and forth at a speed of 300 mm / min, to achieve a 25 mm x 25 mm adhesive area. After leaving the sample standing for 30 minutes, it was attached vertically to a holding strength tester adjusted to 40°C and 50% RH. After 20 minutes of temperature and humidity control, a 1 kg load was applied to the bottom of the test sample. The amount of movement of the adhesive (displacement, mm) after 1 hour was used to evaluate the holding strength performance. ○ and △ were judged to be practical. ○: Misalignment width within 1mm △: Misalignment width 1mm or more, less than 5mm ×: Misalignment width 5mm or more, or falling

[0082] [Ball tuck] The hot melt adhesive composition was applied at a coating temperature of 160°C in an amount of 100 g / m 2 A 100 μm thick PET film was coated with the adhesive so that the adhesive would be 100 μm thick, and a release-treated PET film was attached to it to prepare a pressure-sensitive adhesive sheet sample for evaluation. The pressure-sensitive adhesive sheet sample was then cut perpendicular to the flow direction into a size of 25 mm wide and 250 mm long to prepare a test sample. The release-treated PET film was peeled off from the test sample and the sample was fixed adhesive side up on an inclined plate with an inclination angle of 30 degrees. A PET film for the runway was attached to the top, and a steel ball (1 / 32 to 32 / 32 inches) was rolled across the sample with a runway of 10 cm and an adhesive surface of 10 cm. The diameter number of the ball that stopped near the center of the adhesive surface was recorded. Measurements were carried out in an atmosphere of 23°C and 50% relative humidity. ○ and △ were judged to be practical. The resulting adhesive sheet was prepared to a size of 25 mm wide and 250 mm long. The release sheet was peeled off from the adhesive sheet and the sheet was fixed with the adhesive side facing up on an inclined plate with an inclination angle of 30 degrees. A PET film for the runway was attached to the top, and a steel ball (1 / 32 to 32 / 32 inches) was rolled across the sample with a runway of 10 cm and an adhesive surface of 10 cm, and the diameter number of the ball that stopped near the center of the adhesive surface was recorded. Measurements were carried out in an atmosphere of 5°C or 23°C and 50% relative humidity. 3) Ball tack The resulting adhesive sheet was prepared to a size of 25 mm wide and 250 mm long. The release sheet was peeled off from the adhesive sheet, and the sheet was fixed adhesive-side up on an inclined plate with an inclination angle of 30 degrees. A PET film for the runway was attached to the top, and a steel ball (1 / 32 to 32 / 32 inches) was rolled across the sample, with a runway of 10 cm and an adhesive surface of 10 cm. The diameter number of the ball that stopped near the center of the adhesive surface was recorded. Measurements were performed at 5°C or 23°C and a relative humidity of 50%. ○:#25 or above △: #10 or more, less than #25 ×: Less than #10

[0083] [Heat and humidity resistance test] The hot melt adhesive composition was applied at a coating temperature of 160°C in an amount of 100 g / m 2 A 100 μm thick PET film was coated with the adhesive so that the adhesive would be 100 μm thick, and a release-treated PET film was attached to it to prepare a pressure-sensitive adhesive sheet sample for evaluation. The pressure-sensitive adhesive sheet sample was then cut perpendicular to the flow direction into a size of 100 mm wide and 100 mm long to prepare a test sample. The release-treated PET film was peeled off from the test sample, and the test sample was attached to a SUS plate, attached vertically, and left to stand in a testing machine adjusted to 80°C and 50% RH for 500 hours, and any changes in appearance such as peeling were checked. ◯ and △ were judged to be usable. ○: No change in appearance △: Changes in appearance such as peeling and lifting were observed in some of the four corners ×: Changes in appearance such as peeling and lifting were observed in most of the four corners and edges.

[0084] As is clear from the results in Tables 1 and 2, the comparative examples showed insufficient results, whereas the examples showed good results.

Claims

1. The adhesive composition contains a styrene-based block copolymer (A), a tackifying resin (B), a mineral oil (C), a wax (D), and a polybutene (E), the content of polybutene (E) is less than 5% by mass relative to 100% by mass of the hot melt pressure-sensitive adhesive composition; The melt viscosity (η1) at 160°C is 25,000 mPa s or less, The melt viscosity (η2) at 180°C is 15,000 mPa s or less, and a ratio (η1 / η2) of the melt viscosity (η1) at 160°C to the melt viscosity (η2) at 180°C of 1.0 to 2.

5.

2. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the styrene-isoprene-styrene block copolymer is contained in an amount of 50% by mass or more relative to 100% by mass of the styrene-based block copolymer (A).

3. 3. The hot melt pressure-sensitive adhesive composition according to claim 2, wherein the styrene block copolymer (A) comprises a styrene block copolymer (A') that satisfies the following (i) and (ii): (i) Diblock ratio is 10 to 80% by mass (ii) Styrene ratio is 10 to 40% by mass

4. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the tackifier resin (B) is at least one selected from the group consisting of petroleum-based resins, rosin-based resins, and terpene-based resins.

5. The hot melt pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the wax (D) is polyethylene or polypropylene having a melting point of 100°C or higher.

6. A laminate comprising a substrate and a pressure-sensitive adhesive layer comprising the hot-melt pressure-sensitive adhesive composition according to claim 5.

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