Hot-melt type adhesive composition, adhesive tape and article

Abstract

To provide a hot-melt type adhesive composition which contains many plant-derived components, is excellent in 180-degree peel adhesive force, constant load holding power and shear retention force among adhesive characteristics and has high removability and to provide an adhesive tape having an adhesive layer composed of the adhesive composition.SOLUTION: There is provided a hot-melt type adhesive composition which comprises at least a styrene-based block copolymer (A) having a farnesene structure, a thermoplastic resin (B) and a tackifier resin (C), wherein the styrene-based block copolymer (A) has a weight average molecular weight (Mw) of 10000 to 500000, the thermoplastic resin (B) has a kinematic viscosity (40°C) of 150 or more and 200000 or less and has a number average molecular weight (Mn) of 450 or more and 4000 or less, the tackifier resin (C) has a softening point of 100°C or more and the hot-melt type adhesive composition comprises 30 to 500 pts.mass of the tackifier resin (C) based on 100 pts.mass of the styrene-based block copolymer (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hot melt pressure-sensitive adhesive composition, more specifically to a hot melt pressure-sensitive adhesive composition containing a styrene-based block copolymer having a farnesene structure, and a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. [Background technology]

[0002] Because hot melt pressure sensitive adhesives are solvent-free and therefore reduce the environmental impact during production, they are widely used in fastening components that make up relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, as well as relatively small electronic devices such as mobile electronic terminals, cameras, and personal computers. Furthermore, hot melt pressure sensitive adhesives containing plant-derived components have been proposed, as they can be produced with less environmental impact than those containing petroleum-derived components (see, for example, Patent Documents 1 and 2).

[0003] Furthermore, from the viewpoint of protecting the global environment and with the aim of saving resources, there is an increasing trend to disassemble used products to reuse or recycle the parts used in the products. In this case, if an adhesive tape is used, it is necessary to peel the adhesive tape attached to the parts, and therefore there is a demand for an adhesive tape with excellent removability that can be peeled and removed without leaving any adhesive residue on the parts.

[0004] Furthermore, since it is important for adhesive tapes used to fix components to be able to fix the components without peeling during use, it is desirable for them to have good 180° peel adhesive strength, constant load holding strength, and shear holding strength. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-237257 [Patent Document 2] Japanese Patent Publication No. 2023-162607 Summary of the Invention [Problem to be solved by the invention]

[0006] The laminate described in Patent Document 1 has high interlayer adhesive strength, and even if it contains a softener, there is little bleed-out of the softener, and the hot melt composition described in Patent Document 2 has high workability, excellent initial adhesion when attached to an adherend, high peel strength resulting in high adhesive strength, and significantly reduced oozing of oil and fat components. However, neither of these documents pays attention to removability when peeling off the adhesive tape attached to a part, nor does it take into consideration the compatibility of 180° peel adhesive strength, constant load holding strength, shear holding strength, and removability that are required for an adhesive tape used to fix parts.

[0007] Therefore, an object of the present invention is to provide a hot melt pressure-sensitive adhesive composition which contains more plant-derived components than conventional hot melt pressure-sensitive adhesive compositions made from petroleum-derived components, and which has excellent 180° peel adhesion, constant load holding strength and shear holding strength, as well as high removability, and a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made from the pressure-sensitive adhesive composition. [Means for solving the problem]

[0008] The present invention includes the following aspects. [1] A composition comprising at least a styrene-based block copolymer (A) having a farnesene structure, a thermoplastic resin (B), and a tackifier resin (C), wherein the kinematic viscosity (40°C) of the thermoplastic resin (B) is 150 mm 2 / s or more 200,000mm 2 / s or less or a number average molecular weight (Mn) of 450 or more and 4000 or less, the softening point of the tackifier resin (C) is 100°C or more, and the hot melt pressure-sensitive adhesive composition contains 30 to 500 parts by mass of the tackifier resin (C) per 100 parts by mass of the styrene block copolymer (A).

[0009] [2] The hot melt pressure-sensitive adhesive composition according to [1] above, wherein the styrene-based block copolymer (A) comprises a polymer block (A-1) consisting of structural units derived from styrene and a polymer block (A-2) consisting of structural units derived from farnesene.

[0010] [3] The kinematic viscosity (40 ° C) of the thermoplastic resin (B) is 20,000 mm 2 / s or more 200,000mm 2 The hot melt pressure-sensitive adhesive composition according to the above [1] or [2], wherein the composition has a viscosity of 1000 to 1200 ps / s or less, or a number average molecular weight (Mn) of 1,000 or more and 4,000 or less.

[0011] [4] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to [3], wherein the styrene block copolymer (A) has a weight average molecular weight (Mw) of 10,000 to 500,000.

[0012] [5] The hot melt pressure-sensitive adhesive composition according to any one of the above [2] to [4], wherein the content of the polymer block (A-1) in the total amount of the styrene-based block copolymer (A) is 35 mass % or less.

[0013] [6] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to [5], which contains 5 to 300 parts by mass of the thermoplastic resin (B) per 100 parts by mass of the styrene block copolymer (A).

[0014] [7] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to [6], wherein the thermoplastic resin (B) is liquid at 23°C.

[0015] [8] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to [7], wherein the thermoplastic resin (B) contains an olefin resin.

[0016] [9] The hot melt pressure-sensitive adhesive composition according to any one of [1] to [8], wherein a 40 μm thick pressure-sensitive adhesive layer obtained from the hot melt pressure-sensitive adhesive composition has a haze of 10% or less.

[0017]

[10] The storage modulus G' at 180°C is 5×10 3 The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to [9], which is:

[0018]

[11] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to

[10] , which has a biomass ratio of 30% or more.

[0019]

[12] The hot melt pressure-sensitive adhesive composition according to any one of the above [1] to

[11] , which contains one or more selected from the group consisting of an antioxidant, an ultraviolet absorber, a heat stabilizer, and a resin reinforcer.

[0020]

[13] A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer made of the hot melt pressure-sensitive adhesive composition according to any one of [1] to

[12] above.

[0021]

[14] An article using the adhesive tape described in

[13] above. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a hot melt pressure-sensitive adhesive composition that contains a large amount of plant-derived components, and that has excellent adhesive properties, particularly excellent 180° peel adhesion, constant load holding strength and shear holding strength, as well as high removability, and a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a conceptual diagram showing a method for measuring shear holding strength. [Figure 2] FIG. 1 is a conceptual diagram showing a method for measuring a constant load holding force. DETAILED DESCRIPTION OF THE INVENTION

[0024] The hot melt pressure-sensitive adhesive composition of the present invention contains at least a styrene-based block copolymer (A) having a farnesene structure, a thermoplastic resin (B), and a tackifier resin (C), wherein the thermoplastic resin (B) has a kinematic viscosity (40°C) of 150 mm 2 / s or more 200,000mm 2 / s or less, or a number average molecular weight (Mn) of 450 to 4000, the softening point of the tackifier resin (C) is 100°C or higher, and the hot melt pressure-sensitive adhesive composition contains 30 to 500 parts by mass of the tackifier resin (C) per 100 parts by mass of the styrene block copolymer (A).

[0025] Due to the above-mentioned characteristics, the hot melt pressure-sensitive adhesive composition of the present invention contains a large amount of plant-derived components and yet has excellent 180° peel adhesive strength, constant load holding strength and shear holding strength, as well as excellent removability.

[0026] The hot melt pressure-sensitive adhesive composition of the present invention will be described in more detail below based on its constituent elements.

[0027] <Hot melt pressure sensitive adhesive composition> (Styrene-based block copolymer (A) having a farnesene structure) The styrene-based block copolymer (A) having a farnesene structure in the present invention (hereinafter, may be referred to as the styrene-based block copolymer (A)) preferably comprises a polymer block (A-1) consisting of structural units derived from styrene and a polymer block (A-2) consisting of structural units derived from farnesene.

[0028] When the styrene-based block copolymer (A) having a farnesene structure in the present invention comprises a polymer block (A-1) composed of structural units derived from styrene and a polymer block (A-2) composed of structural units derived from farnesene, it may be a diblock copolymer composed of one polymer block (A-1) and one polymer block (A-2), a triblock copolymer composed of two polymer blocks (A-1) and one polymer block (A-2), or a multiblock copolymer composed of a total of four or more polymer blocks (A-1) and polymer blocks (A-2). The styrene-based block copolymer (A) may be used alone or in combination with two or more. Triblock copolymers are particularly preferred because they have a good balance between viscosity and elasticity and are likely to exhibit good adhesive properties.

[0029] (Polymer block (A-1)) Examples of styrene-based compounds constituting the styrene-derived structural units in the polymer block (A-1) include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 4-methoxystyrene, monochlorostyrene, and dichlorostyrene. These styrene-based compounds may be used alone or in combination of two or more.

[0030] The content of the polymer block (A-1) consisting of structural units derived from styrene in the total amount of the styrene-based block copolymer (A) is preferably 35% by mass or less, more preferably 10 to 30% by mass, and even more preferably 15 to 25% by mass. The polymer block (A-1) consisting of structural units derived from styrene acts as a physical pseudo-crosslinking point, so when the content is within the above range, it can exhibit a good balance of shear holding strength under heating, high cohesive strength required for recyclability, and appropriate viscosity required for tackiness during application and suitability for hot-melt coating.

[0031] (Polymer block (A-2)) The polymer block (A-2) may contain only structural units (i) derived from farnesene, or may contain structural units (ii) derived from a conjugated diene other than farnesene in addition to structural units derived from farnesene. The farnesene-derived structural unit (i) is farnesene. Examples of diene compounds constituting the structural unit (ii) derived from a conjugated diene other than farnesene include isoprene, butadiene, 2,3-dimethyl-butadiene, 2-phenyl-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, and chloroprene. These may be used alone or in combination of two or more. Among these, at least one of isoprene, butadiene and myrcene is more preferred, and at least one of butadiene and isoprene is even more preferred.

[0032] The content of the farnesene-derived structural unit (i) in the total amount of the polymer block (A-2) is 1 to 100 mass%, preferably 60 to 100 mass%, more preferably 70 to 100 mass%, more preferably 75 to 100 mass%, even more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%. Furthermore, the content of the structural unit (ii) derived from a conjugated diene other than farnesene in the total amount of the polymer block (A-2) is 0 to 99 mass%, preferably 0 to 40 mass%, more preferably 0 to 30 mass%, more preferably 0 to 25 mass%, even more preferably 0 to 10 mass%, and still more preferably 0 to 5 mass%.

[0033] The content of the polymer block (A-2) in the total amount of the styrene-based block copolymer (A) is preferably 50% by mass or more, more preferably 60 to 90% by mass, and even more preferably 70 to 85% by mass. The polymer block (A-2) contributes to imparting flexibility to the pressure-sensitive adhesive composition and adjusting the cohesive strength of the pressure-sensitive adhesive composition in a well-balanced manner. Therefore, when the content is within the above range, the pressure-sensitive adhesive composition can exhibit a well-balanced shear holding strength under heating, high cohesive strength required for recyclability, and appropriate viscosity required for tackiness during application and suitability for hot-melt coating.

[0034] The glass transition temperature (Tg) of the styrene block copolymer (A) is preferably 0°C or lower, more preferably -80 to -20°C, and even more preferably -70 to -30°C. When the glass transition temperature (Tg) is within this range, the polymer block (A-1) acts as a hard segment by acting as a physical pseudo-crosslinking point, and when used in a hot melt pressure-sensitive adhesive composition, it can exhibit excellent shear holding power, removability, and hot melt coatability. In addition, the polymer block (A-2) functions as a soft segment with excellent flexibility, and when used in a hot melt pressure-sensitive adhesive composition, it can exhibit excellent low-temperature properties and impact resistance.

[0035] The glass transition temperature of the styrene block copolymer (A) is an extrapolated onset temperature observed in a curve obtained by analyzing the styrene block copolymer (A) with a differential scanning calorimeter (DSC).

[0036] The weight-average molecular weight of the styrene-based block copolymer (A) is preferably 10,000 to 500,000, more preferably 20,000 to 400,000, even more preferably 50,000 to 300,000, particularly preferably 50,000 to 200,000, and most preferably 100,000 to 150,000. When the weight-average molecular weight of the styrene-based block copolymer (A) is within the above range, the hot-melt pressure-sensitive adhesive composition can have good adhesive properties such as adhesive strength, cohesive strength, and tackiness, and can also have fluidity suitable for melt molding.

[0037] The molecular weight distribution (weight average molecular weight / number average molecular weight) of the styrene-based block copolymer (A) is preferably in the range of 1.0 to 2.0, more preferably in the range of 1.0 to 1.7, and even more preferably in the range of 1.0 to 1.5. When the molecular weight distribution of the styrene-based block copolymer (A) is in the above range, excellent shear holding power and removability are achieved when blended with the thermoplastic resin (B) described below in a predetermined range.

[0038] The weight-average molecular weight and number-average molecular weight in the present invention refer to values ​​measured by gel permeation chromatography (GPC) and calculated in terms of standard polystyrene. Specifically, they can be measured using a GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation under the following conditions: Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100 μl Eluent: tetrahydrofuran ·Flow rate: 1.0ml / min ·Measurement temperature: 40℃ Columns: 1 TSKgel G5000HXL + 1 TSKgel G4000HXL + 1 TSKgel G3000HXL + 2 TSKgel G2500HXL Guard column: TSKgel HXL-H Detector: Differential refractometer Weight average molecular weight of standard polystyrene: 5 million to 5 million (manufactured by Tosoh Corporation)

[0039] The styrene-based block copolymer (A) may be synthesized by polymerizing raw material monomers, or a commercially available product may be used. The polymerization method is not particularly limited, and examples thereof include anionic polymerization and atom transfer radical polymerization (ATRP). Detailed descriptions of each polymerization method are omitted here. Examples of anionic polymerization include anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid salt such as an alkali metal or alkaline earth metal salt, anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound, and anionic polymerization using an organic rare earth metal complex as a polymerization initiator. Examples of ATRP include polymerization using an organic halide or sulfonyl halide compound as an initiator in the presence of a transition metal compound and a nitrogen-containing compound. Examples of commercially available products include Septon SF902 (product name, manufactured by Kuraray Co., Ltd., styrene content: 18% by weight), Septon SF903 (product name, manufactured by Kuraray Co., Ltd., styrene content: 30% by weight), and Septon SF904 (product name, manufactured by Kuraray Co., Ltd., styrene content: 21% by weight).

[0040] The styrene-based block copolymer (A) contains a structural unit (i) derived from farnesene. Farnesene can be produced industrially using microorganisms, starting from sugar extracted from plants such as sugarcane. The hot-melt pressure-sensitive adhesive composition of the present invention uses farnesene as a raw material, and therefore has a high biomass content. It is carbon-neutral when incinerated, and therefore reduces the environmental load. Farnesene can be divided into α-farnesene and β-farnesene based on their structural differences. In the present invention, it is more preferable to use β-farnesene.

[0041] The biomass degree refers to the content of plant-derived components, and the biomass degree of the styrene-based block copolymer (A) is preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more. Note that the biomass degree in the present invention is an index that indicates the content ratio of bio-derived substances in a target substance, measured in accordance with ASTM D6866-16.

[0042] The content of the styrene block copolymer (A) in the total amount of the hot melt pressure-sensitive adhesive composition of the present invention is preferably 10 to 80 mass%, more preferably 20 to 60 mass%, and even more preferably 20 to 50 mass%. When the content of the styrene block copolymer (A) is within the above range, the cohesive strength inherent to the polymer is appropriately exhibited, and the composition is particularly excellent in shear holding strength and removability.

[0043] (Thermoplastic resin (B)) By blending the thermoplastic resin (B) in addition to the styrene-based block copolymer (A) described above, the hot-melt pressure-sensitive adhesive composition of the present invention can significantly improve hot-melt coatability without reducing adhesive strength, constant load holding power, and shear holding power.

[0044] The thermoplastic resin (B) in the present invention may be, for example, a hydrocarbon oil such as a paraffinic, olefinic, naphthenic, or aromatic oil; a vegetable oil such as peanut oil or rosin; a phosphate ester; a low-molecular-weight polyethylene glycol; liquid paraffin; a hydrocarbon synthetic oil such as a low-molecular-weight polyethylene, an ethylene-α-olefin copolymer oligomer, liquid polybutene, liquid polyisoprene or a hydrogenated product thereof, or liquid polybutadiene or a hydrogenated product thereof. These may be used alone or in combination of two or more, and are not particularly limited as long as the thermoplastic resin as a whole satisfies the conditions described below.

[0045] The number average molecular weight of the thermoplastic resin (B) is more preferably 450 to 4000, even more preferably 1000 to 3000, and particularly preferably 1000 to 2000. When the number average molecular weight of the thermoplastic resin (B) is within the above range, the adhesive properties such as adhesive strength, cohesive strength, and tack of the hot melt pressure-sensitive adhesive composition become good, and bleeding out during re-peeling can be suppressed. In addition, the composition can have fluidity suitable for melt molding.

[0046] The thermoplastic resin (B) has a kinematic viscosity at 40°C of 150 to 200,000 mm 2 / s, 1,000 to 200,000 mm 2 / s, and 20,000 to 200,000 mm 2 / s, more preferably 20,000 to 100,000 mm2 / s. When the kinematic viscosity of the thermoplastic resin (B) at 40°C is within the above range, it is possible to exhibit the cohesive strength required for shear holding power while maintaining good tackiness. In general, the kinematic viscosity of the thermoplastic resin (B) at 40°C tends to increase in correlation with the molecular weight of the thermoplastic resin (B).

[0047] The kinematic viscosity of the thermoplastic resin (B) at 40° C. in the present invention is measured by a method in accordance with JIS K2283, specifically, by a glass capillary viscometer.

[0048] The thermoplastic resin (B) is preferably liquid at room temperature (23° C.) because it can exhibit good tackiness.

[0049] The content of the thermoplastic resin (B) relative to 100 parts by mass of the styrene-based block copolymer (A) is preferably 5 to 300 parts by mass, more preferably 20 to 250 parts by mass, and even more preferably 30 to 200 parts by mass. When the content of the thermoplastic resin (B) is within the above range, a hot melt pressure-sensitive adhesive composition having an excellent balance of good tackiness, shear holding power, and removability can be obtained.

[0050] (Tackifying resin (C)) The hot melt pressure-sensitive adhesive composition of the present invention further contains a tackifier resin (C) in addition to the above-mentioned styrene block copolymer (A) and thermoplastic resin (B). By containing the tackifier resin (C), the hot melt pressure-sensitive adhesive composition of the present invention increases adhesive strength to a practically sufficient level and satisfies properties such as adhesive strength, shear holding strength, constant load holding strength, and removability.

[0051] The tackifying resin (C) in the present invention is preferably compatible with the styrene-based block copolymer (A) and the thermoplastic resin (B) so as to form a polymer blend. Such a compatible resin is not particularly limited, and may be appropriately selected from various known tackifying resins such as petroleum resins, styrene-based resins (excluding the styrene-based block copolymer (A)), coumarone-indene resins, terpene resins, modified terpene resins, rosin-based resins, rosin derivative resins, and ketone-based resins.

[0052] Examples of petroleum resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, and hydrogenated products thereof (for example, alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins).

[0053] Examples of styrene-based resins include those containing a homopolymer of styrene as the main component, those containing a homopolymer of α-methylstyrene as the main component, those containing a homopolymer of vinyltoluene as the main component, and those containing a copolymer containing two or more of styrene, α-methylstyrene, and vinyltoluene as the main component in the monomer composition (for example, an α-methylstyrene / styrene copolymer resin containing an α-methylstyrene / styrene copolymer as the main component).

[0054] The coumarone-indene resin can be a resin containing coumarone and indene as monomer components that make up the resin skeleton (main chain). Other monomer components that can be included in the resin skeleton besides coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0055] Examples of terpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, etc. Examples of modified terpene resins include those obtained by modifying the above-mentioned terpene resins (phenol-modified, catechol-modified, styrene-modified, hydrogenated-modified, hydrocarbon-modified, etc.). Specific examples include terpene phenol resins, styrene-modified terpene resins, hydrogenated terpene resins, terpene catechol resins, etc.

[0056] The term "terpene phenolic resin" refers to a polymer containing a terpene residue and a phenol residue, and encompasses both a copolymer of a terpene and a phenolic compound (a terpene-phenol copolymer resin) and a phenol-modified terpene resin (a terpene resin, typically an unmodified terpene resin) modified with phenol. Suitable examples of terpenes constituting the terpene phenolic resin include monoterpenes such as α-pinene, β-pinene, and limonene (including d-, l-, and d / l-forms (dipentene)).

[0057] Specific examples of rosin-based resins include unmodified rosin (gum rosin, wood rosin, tall oil rosin, etc., also known as raw rosin), modified rosin (rosin modified by hydrogenation, disproportionation, polymerization, other chemical modifications, etc.), etc. Examples of rosin derivative resins include esters of unmodified rosin and modified rosin, unsaturated fatty acid modified rosins of unmodified rosin and modified rosin, unsaturated fatty acid modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids, rosin alcohols obtained by reducing the carboxyl groups of unmodified rosin, modified rosin, unsaturated fatty acid modified rosins, or unsaturated fatty acid modified rosin esters, metal salts of rosins (particularly rosin esters) such as unmodified rosin, modified rosin, and various rosin derivatives, and rosin phenolic resins obtained by adding phenol to rosins (unmodified rosin, modified rosin, various rosin derivatives, etc.) using an acid catalyst and then thermally polymerizing the resulting mixture.

[0058] Among these, petroleum resins, rosin resins, and terpene resins are preferred from the viewpoints of good compatibility with the styrene block copolymer (A) and the thermoplastic resin (B) and improving removability, and terpene resins and rosin resins are preferred from the viewpoints of increasing the content of plant-derived components and increasing the biomass content.

[0059] In the present invention, a low-polarity tackifier resin is preferably used as the tackifier resin (C) from the viewpoint of excellent compatibility with the styrene-based block copolymer (A) and the thermoplastic resin (B). When the tackifier resin (C) has good compatibility with the styrene-based block copolymer (A) and the thermoplastic resin (B), the addition of the tackifier resin (C) is preferred because this allows for a sufficient improvement in physical properties. Furthermore, from the viewpoint of preventing deterioration of the tackifier resin (C) during the melting process of the hot-melt pressure-sensitive adhesive composition, a hydrogenated tackifier resin is preferably used.

[0060] In the hot melt pressure-sensitive adhesive composition of the present invention, when the tackifier resin (C) has excellent compatibility with the styrene block copolymer (A) and the thermoplastic resin (B), the haze of the resulting pressure-sensitive adhesive layer can be kept low. The haze of a 40 μm thick pressure-sensitive adhesive layer obtained from the hot-melt pressure-sensitive adhesive composition is preferably 10% or less, more preferably 8% or less. When the haze of the pressure-sensitive adhesive layer is within the above range, the tackifier resin (C) is sufficiently compatible with the styrene-based block copolymer (A) and the thermoplastic resin (B), and the effect of improving physical properties by blending the tackifier resin (C) can be fully obtained.

[0061] The haze in the present invention is measured by the method described in the examples.

[0062] The tackifier resin (C) contains at least one resin having a softening point of 100°C or higher from the viewpoint of shear holding strength at high temperatures. By blending a tackifier resin (C) with such a high softening point, it is possible to significantly improve not only adhesive strength and shear holding strength, but also constant load holding strength and removability. From the viewpoint of further improving these properties, the softening point of the tackifier resin (C) is preferably 100°C or higher, and more preferably 110°C or higher. The softening point of the tackifier resin (C) is preferably 250°C or lower, more preferably 180°C or lower, even more preferably 160°C or lower, and most preferably 150°C or lower. When the softening point of the tackifier resin (C) is within the above range, the resin can be prevented from becoming too hard and a viscosity suitable for the adhesive can be obtained. Furthermore, the shear holding strength and constant load holding strength in a high-temperature environment can be improved. One or more types of tackifier resin (C) may be used. When two or more types are used, the tackifier resin having the suitable softening point preferably accounts for 50% by mass or more, and more preferably 60% by mass or more, of the total mass of all tackifier resins.

[0063] The softening point of the tackifier resin (C) in the present invention is a value determined by the ring and ball method in accordance with JIS K5902.

[0064] The blending amount of the tackifier resin (C) is 30 to 500 parts by mass, preferably 30 to 300 parts by mass, more preferably 50 to 200 parts by mass, and even more preferably 75 to 175 parts by mass, per 100 parts by mass of the styrene-based block copolymer (A). When the blending amount of the tackifier resin (C) is within the above range, adhesive strength, shear strength, and constant-load strength can be more significantly improved. In particular, shear strength and constant-load strength under high-temperature conditions can be improved.

[0065] (anti-aging agent) The hot melt pressure-sensitive adhesive composition of the present invention may contain an antioxidant, if necessary. The use of an antioxidant prevents thermal degradation of the pressure-sensitive adhesive, improving its quality stability. One antioxidant may be used alone, or two or more antioxidants may be used in combination. Examples of antioxidants include phosphorus-based antioxidants, phenol-based antioxidants (e.g., hindered phenol-based antioxidants), hindered amine-based antioxidants, aromatic amine-based antioxidants, and sulfur-based antioxidants. Although not particularly limited, the amount of antioxidant contained in the hot melt pressure-sensitive adhesive composition disclosed herein may be 10 parts by mass or less, suitably 7 parts by mass or less, and may be 3 parts by mass or less, per 100 parts by mass of the total of the styrene-based block copolymer (A) having a farnesene structure, the thermoplastic resin (B), and the tackifier resin (C). The amount of the antioxidant may be, for example, 0.1 part by weight or more, or may be 0.5 part by weight or more, or may be 1 part by weight or more, per 100 parts by weight of the total of the styrene-based block copolymer (A) having a farnesene structure, the thermoplastic resin (B), and the tackifier resin (C).

[0066] (optional ingredient) The hot melt pressure-sensitive adhesive composition of the present invention may contain one or more rubbery polymers other than the styrene-based block copolymer, as needed, to the extent that the effects of the present invention are not significantly impaired. Such rubbery polymers include various polymers known in the field of pressure-sensitive adhesives, such as rubber-based, acrylic-based, polyester-based, urethane-based, polyether-based, silicone-based, polyamide-based, and fluorine-based polymers.

[0067] The hot melt pressure-sensitive adhesive composition of the present invention may contain, as necessary, various additives commonly used in the field of pressure-sensitive adhesives, such as leveling agents, crosslinking agents, crosslinking aids, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), antistatic agents, ultraviolet absorbers, light stabilizers, etc. Such various additives may be conventionally known and used in the usual manner, provided that the effects of the present invention are not significantly impaired.

[0068] The hot melt pressure-sensitive adhesive composition of the present invention has a storage modulus G' at 180°C of 5 x 10 3 Pa or less, and 3 Pa or less is more preferable, and 1×10 3 It is more preferably not more than 500 Pa, and most preferably not more than 500 Pa. When the storage modulus G' is in the above range, excellent melt viscosity is exhibited at high temperatures, and therefore, favorable kneading workability and hot melt coating suitability can be achieved.

[0069] The storage modulus G' at 180°C is determined by measuring dynamic viscoelasticity using temperature dispersion. Using a viscoelasticity tester (manufactured by TA Instruments Japan, product name: ARES G2), the hot-melt pressure-sensitive adhesive composition is formed into a test piece approximately 2 mm thick, and the test piece is sandwiched between parallel disks with a diameter of 8 mm, which are the measurement section of the tester, and the storage modulus (G') is measured from 30°C to 200°C at a frequency of 1 Hz and a heating rate of 2°C / min.

[0070] From the viewpoint of reducing the environmental impact, the hot melt pressure-sensitive adhesive composition of the present invention preferably has a biomass ratio of 30% or more, more preferably 40% or more, and even more preferably 50% or more. The biomass ratio was measured in accordance with ASTM D6866-16.

[0071] <Form of Hot Melt Pressure-Sensitive Adhesive Composition> The composition of the hot melt pressure-sensitive adhesive composition of the present invention has been described in detail above. This hot melt pressure-sensitive adhesive composition can be a hot melt pressure-sensitive adhesive composition obtained by melting and kneading the above-mentioned styrene block copolymer (A) having a farnesene structure, the thermoplastic resin (B), the tackifier resin (C), and optional components (other pressure-sensitive adhesive raw materials), or a solution pressure-sensitive adhesive composition obtained by dissolving the components in a predetermined organic solvent (toluene, ethyl acetate, etc.).

[0072] <Uses of hot melt pressure sensitive adhesive compositions> The hot melt pressure-sensitive adhesive composition of the present invention is suitably used for pressure-sensitive adhesive products in the form of a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition, or a laminate (e.g., pressure-sensitive adhesive tape) containing the pressure-sensitive adhesive layer. Hereinafter, as an example of the use of the hot melt pressure-sensitive adhesive composition of the present invention, a double-sided pressure-sensitive adhesive tape formed by applying the above-mentioned pressure-sensitive adhesive composition to both sides of a substrate will be described. Note that a single-sided pressure-sensitive adhesive tape is similar to a double-sided pressure-sensitive adhesive tape except that the pressure-sensitive adhesive composition is applied to one side of the substrate. Furthermore, a substrateless pressure-sensitive adhesive tape is similar to a double-sided pressure-sensitive adhesive tape except that the pressure-sensitive adhesive composition is applied to a release liner, resulting in a pressure-sensitive adhesive layer alone.

[0073] The double-sided pressure-sensitive adhesive tape using the hot-melt pressure-sensitive adhesive composition of the present invention has the above-mentioned pressure-sensitive adhesive composition applied to both sides of a substrate, and further has a release liner attached to the surface of the pressure-sensitive adhesive composition as required.

[0074] The substrate is not particularly limited as long as it has a film or sheet shape to which the hot melt pressure-sensitive adhesive composition can be applied, and examples thereof include plastic films such as polypropylene film, ethylene-propylene copolymer film, polyester film, polyvinyl chloride film, cellophane, polyimide, polycarbonate (PC), and polystyrene (PS); foam sheets made of foams such as polyurethane foam, polyethylene foam, polypropylene foam, ethylene-vinyl acetate copolymer foam, butyl rubber foam, and polyacrylate foam; woven and nonwoven fabrics made by spinning various fibrous materials (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, and metal fibers such as stainless steel); paper such as kraft paper, Japanese paper, and crepe paper; and metal foils such as aluminum foil and copper foil, which can be appropriately selected depending on the application of the pressure-sensitive adhesive tape. As the plastic film, any of unstretched film, uniaxially stretched film, and biaxially stretched film can be used. The surface of the substrate on which the adhesive layer is to be provided may be subjected to adhesion-improving treatment such as application of a primer or corona discharge treatment.

[0075] The thickness of the substrate can be appropriately selected depending on the purpose, but it is generally preferable that it be 1 μm or more and 2 mm or less.

[0076] The release liner can be any conventional release paper, and is not particularly limited. For example, a release liner having a release treatment layer on the surface of a substrate such as a plastic film or paper, or a release liner made of a low-adhesion material such as a fluorine-based polymer (e.g., polytetrafluoroethylene) or a polyolefin-based resin (e.g., polyethylene, polypropylene), can be used. The release treatment layer is formed by surface-treating the substrate with a release treatment agent such as a silicone-based, long-chain alkyl-based, or fluorine-based agent.

[0077] The method for applying the hot melt pressure-sensitive adhesive composition to the substrate is not particularly limited, and known methods can be used, such as a method of dissolving the pressure-sensitive adhesive raw material in an organic solvent and applying the composition (melt spreading method), a method of thinning the composition using multiple heated rolls and applying the composition (calender method), and a method of thermally melting the pressure-sensitive adhesive raw material and applying the composition (hot melt method). The coating device for the hot melt type pressure sensitive adhesive composition is not particularly limited, and coating can be performed using a conventionally known coating machine such as a roll coater, knife coater, bar coater, die coater, air knife coater, gravure coater, variogra coater, or curtain coater.

[0078] The hot melt pressure-sensitive adhesive composition of the present invention can be used in a variety of applications. A pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition can be used alone as a pressure-sensitive adhesive tape, and laminates containing the pressure-sensitive adhesive layer can also be used in a variety of applications. Examples of such applications include pressure-sensitive adhesives and tapes for fixing electronic components, fixing in-vehicle components, protecting surfaces and the like, masking, labeling, bonding, dicing tape, sealing, corrosion prevention and waterproofing, electrical insulation, semiconductor manufacturing, optical display films, pressure-sensitive adhesive optical films, electromagnetic wave shielding, and sealing materials for electrical and electronic components. In addition, since the hot-melt pressure-sensitive adhesive composition does not require a drying process, it is possible to significantly improve the coating speed and realize cost reduction in production. Furthermore, since it does not require crosslinking, it does not require a aging process, and it is possible to move to the next process immediately after production, which can lead to improved workability and time reduction. Furthermore, the use of the hot-melt pressure-sensitive adhesive composition does not require any solvent or reduces the amount of solvent used, which is a great advantage not only from an economical perspective but also from the perspective of environmental protection. [Example]

[0079] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0080] Example 1 100 parts by weight of a styrene-based block copolymer (A) (Septon Bio Series SF902, Mw = 133,000, Mw / Mn = 1.2, manufactured by Kuraray Co., Ltd.) and Irganox 1010 (a hindered phenol-based antioxidant, manufactured by BASF) were placed in a heated kneader and kneaded at a heated temperature (170-190°C) until fully melted. 50 parts by weight of a thermoplastic resin (B) (polybutene HV-300, Mn = 1400, manufactured by ENEOS Corporation) and 100 parts by weight of a tackifier resin (C) (YS Polystar TH130, hydrogenated terpene phenol, softening point 130°C, manufactured by Yasuhara Chemical Co., Ltd.) were added to the melt and further kneaded at a heated temperature (140-190°C) to obtain a hot-melt pressure-sensitive adhesive composition. This adhesive composition was sandwiched between 75 μm thick release PET sheets and melted using a heat press under conditions of 200° C.×2 MPa×3 minutes to prepare a 50 μm thick adhesive sheet.

[0081] (Examples 2 to 10, Comparative Examples 1 to 4) Pressure-sensitive adhesive sheets were prepared in the same manner as in Example 1, except that the formulation of the pressure-sensitive adhesive composition was changed as shown in Tables 1 to 3.

[0082] <Ingredients> SF902: Septon Bio Series SF902 (hydrogenated styrene-farnesene block copolymer, polymer block (A-1) / polymer block (A-2)=18 wt% / 82 wt%, Mw=133,000, Mw / Mn=1.2, manufactured by Kuraray Co., Ltd.) SF903: Septon Bio Series SF903 (hydrogenated styrene-farnesene block copolymer, polymer block (A-1) / polymer block (A-2)=30 wt% / 70 wt%, Mw=243,000, Mw / Mn=1.4, manufactured by Kuraray Co., Ltd.) SF904: Septon Bio Series SF904 (hydrogenated styrene-farnesene block copolymer, polymer block (A-1) / polymer block (A-2)=21 wt% / 79 wt%, Mw=78,500, Mw / Mn=1.1, manufactured by Kuraray Co., Ltd.) LV50: Nisseki Polybutene LV-50 (Polybutene, Mn=430, Kinematic viscosity (40℃) 110mm 2 / s, manufactured by ENEOS) LV100: Nisseki Polybutene LV-100 (Polybutene, Mn=500, Kinematic viscosity (40℃) 205mm 2 / s, manufactured by ENEOS) HV300: Nisseki Polybutene HV-300 (Polybutene, Mn = 1400, Kinematic viscosity (40°C) 26,000 mm 2 / s, manufactured by ENEOS) HV1900: Nisseki Polybutene HV-1900 (Polybutene, Mn = 2900, Kinematic viscosity (40°C) 160,000 mm 2 / s, manufactured by ENEOS) TH130: YS Polyster TH130 (hydrogenated terpene phenol, softening point 130°C, manufactured by Yasuhara Chemical) UH115: YS Polyster UH115 (hydrogenated terpene phenol, softening point 115°C, manufactured by Yasuhara Chemical) PX1150N: YS Resin PX1150N (terpene resin, softening point 115°C, manufactured by Yasuhara Chemical) P115: Alcon P-115 (hydrogenated petroleum resin, softening point 115°C, manufactured by Arakawa Chemical Industries) FTR6100: FTR6100 (aromatic hydrocarbon resin, softening point 95°C, manufactured by Mitsui Chemicals) P90: Alcon P-90 (hydrogenated petroleum resin, softening point 90°C, manufactured by Arakawa Chemical Industries) PCJ: Haritack PCJ (polymerized rosin ester, softening point 124°C, manufactured by Harima Chemicals) KE100: Pine Crystal KE-100 (rosin derivative, softening point 100°C, manufactured by Arakawa Chemical) A75: Super Ester A-75 (disproportionated rosin ester, softening point 75°C, manufactured by Arakawa Chemical Industries, Ltd.) Irg1010: Irganox1010 (hindered phenol antioxidant, manufactured by BASF)

[0083] <Evaluation method> The pressure-sensitive adhesive tapes having pressure-sensitive adhesive layers made of the hot-melt pressure-sensitive adhesive compositions prepared as described above were subjected to measurements according to the methods described below. The results are shown in Tables 1 to 3. In Comparative Example 2, the pressure-sensitive adhesive layer lacked tack, making it impossible to attach the pressure-sensitive adhesive layer to a backing material or adherend, and therefore it was not possible to prepare test pieces necessary for the measurements, and therefore the measurements were not possible.

[0084] (180° peel adhesive strength measurement method) Under an environment of 23°C and 50% RH, one side of the pressure-sensitive adhesive sheets prepared in the Examples and Comparative Examples was lined with a 25 μm thick polyethylene terephthalate film and then cut into a length of 120 mm and a width of 20 mm. Next, the other adhesive side was attached to a stainless steel plate (SUS304 with a hairline finish using #360 sandpaper), and a 2 kg roller was rolled back and forth across the top surface of the pressure-sensitive adhesive sheet. These were then left to stand for 1 hour under an environment of 23°C and 50% RH, thereby producing a test specimen in which the pressure-sensitive adhesive sheet and stainless steel plate were pressure-bonded together. Next, using a Tensilon tensile tester, the strength was measured when the pressure-sensitive adhesive sheet was peeled off in a 180° direction at a pulling speed of 300 mm / min with the stainless steel plate constituting the test specimen fixed.

[0085] (shear holding strength) Under an environment of a temperature of 23°C and a relative humidity of 50% RH, one side of the adhesive tapes produced in the Examples and Comparative Examples was lined with aluminum foil having a thickness of 50 μm, and then cut into a length of 100 mm and a width of 20 mm. Next, the adhesive surface of the cut adhesive tape 2 was attached to a stainless steel plate 3 (SUS304 with a hairline finish using #360 sandpaper) with an adhesive area of ​​20 mm × 20 mm (4 cm 2 ), and a 2 kg roller was moved back and forth once on the top surface of the adhesive tape 2 to apply pressure to prepare a test piece 1. The test piece 1 was prepared by leaving it to stand for 1 hour in an environment of a temperature of 23°C and a relative humidity of 50% RH, in which the adhesive tape 2 and the stainless steel plate 3 were pressure-bonded together. Next, the portion of the adhesive tape 2 of the test piece 1 that was not attached to the stainless steel plate 3 was folded over, and the stainless steel plate 3 side of the test piece 1 was fixed to a holding force meter in an environment at a measurement temperature of 70°C, and then a 500g weight 3 was attached to the folded part of the adhesive tape 2. With the weight 3 attached, the test piece was left in an environment at 70°C, and the time until the adhesive tape 2 peeled (fell) was measured (a conceptual diagram of the measurement method is shown in Figure 1). Note that when the test was held for 1,440 minutes, the test was terminated and the result was recorded as "1,440<".

[0086] (Constant load holding power) One side of each of the pressure-sensitive adhesive tapes prepared in the Examples and Comparative Examples was lined with a 25 μm-thick polyethylene terephthalate film under an environment of 23°C and 50% RH, and then cut to a length of 100 mm and a width of 10 mm. Next, the adhesive side of the cut pressure-sensitive adhesive tape 6 was attached to a stainless steel plate 7 (SUS304 with a hairline finish using #360 sandpaper) so that the attached length was 50 mm. The top surface of the pressure-sensitive adhesive tape 6 was pressed back and forth once with a 2 kg roller, and then the tape was left to stand for 1 hour under an environment of 40°C, thereby preparing a test piece 5 in which the pressure-sensitive adhesive tape 6 and the stainless steel plate 7 were pressure-bonded together. Next, the stainless steel plate 7 side of the test piece 5 was fixed to a constant load holding force meter so that the adhesive tape-attached surface was facing downwards, and then a 100 g weight 8 was attached to the part of the adhesive tape 6 that was not attached to the stainless steel plate 7. With the weight 8 attached, the test piece was left in an environment of a temperature of 23°C and a relative humidity of 50% RH, and the time until the adhesive tape 6 peeled off (fell off) was measured (a conceptual diagram of the measurement method is shown in Figure 2). Note that if the test was held for 180 minutes, the test was terminated and the result was recorded as "180<".

[0087] (Method for measuring removability) One side of the pressure-sensitive adhesive sheets prepared in the Examples and Comparative Examples was lined with a 25 μm-thick polyethylene terephthalate film under an environment of 23°C and 50% RH, and then cut into a length of 120 mm and a width of 20 mm. Next, the other adhesive side was attached to a stainless steel plate (SUS304 with a hairline finish using #360 sandpaper), and a 2 kg roller was rolled back and forth over the top surface of the pressure-sensitive adhesive sheet once. These were then left to stand for 72 hours under an environment of 23°C and 50% RH relative humidity, thereby preparing a test specimen in which the pressure-sensitive adhesive sheet and stainless steel plate were pressure-bonded together. Next, with the stainless steel plate constituting the test piece fixed, the adhesive sheet was peeled off in a 135° direction at a tensile speed of 20 m / min, and the presence or absence of adhesive residue on the stainless steel plate or contamination of the adherend was visually evaluated. ⊚: Peeled off at the interface between the adhesive layer and the stainless steel plate without leaving any adhesive residue or staining. Good: A faint trace of glue remained on the surface of the stainless steel plate, but the adhesive layer peeled off at the interface between the adhesive layer and the stainless steel plate. ×: Destruction occurred within the adhesive layer, or peeling occurred between the polyethylene terephthalate film and the adhesive layer, resulting in adhesive residue or contamination.

[0088] (Method for measuring compatibility) Under an environment of 23°C temperature and 50% RH relative humidity, a 1 mm thick, 50 mm long, and 50 mm wide glass sheet (manufactured by Nippon Sheet Glass Co., Ltd.) was attached to one side of the pressure-sensitive adhesive sheets prepared in the Examples and Comparative Examples. The composition of the glass, pressure-sensitive adhesive layer, and PET separator was used as a test specimen. The haze of the test specimen was measured using a reflectance / transmittance meter (HM-100, manufactured by Murakami Color Research Laboratory Co., Ltd.). The haze of the glass alone used to prepare the test specimen was 0.7%, and the haze of the PET separator alone was 4.8%.

[0089] (Method for measuring storage modulus G') Each pressure-sensitive adhesive layer prepared in the Examples and Comparative Examples was stacked to a thickness of approximately 2 mm and punched out to an 8 mm diameter to prepare a test specimen. Parallel plates with a diameter of 8 mm were attached to a viscoelasticity tester (ARESG2, manufactured by TA Instruments Japan), and the test specimen was sandwiched between them. Measurements were then performed at a frequency of 1 Hz and a heating rate of 2°C / min to determine the storage modulus G' at 180°C.

[0090] (Weight average molecular weight of adhesive resin (GPC)) The weight-average molecular weight defined in this specification refers to a value measured by gel permeation chromatography (GPC) and calculated in terms of standard polystyrene. Specifically, the weight-average molecular weight can be measured using a GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation under the following conditions: Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100 μl Eluent: tetrahydrofuran ·Flow rate: 1.0ml / min ·Measurement temperature: 40℃ Columns: 1 TSKgel G5000HXL + 1 TSKgel G4000HXL + 1 TSKgel G3000HXL + 2 TSKgel G2500HXL Guard column: TSKgel HXL-H Detector: Differential refractometer Weight average molecular weight of standard polystyrene: 5 million to 5 million (manufactured by Tosoh Corporation)

[0091] [Table 1]

[0092] [Table 2]

[0093] [Table 3]

[0094] As can be seen from Tables 1 to 3, the hot-melt pressure-sensitive adhesive composition of the present invention contains a large amount of plant-derived components, and exhibits excellent adhesive properties, particularly excellent 180° peel adhesive strength, constant load holding strength, and shear holding strength, as well as high removability. On the other hand, Comparative Example 1, in which the content of tackifier resin (C) was outside the range of the present invention, exhibited poor shear adhesive strength and did not have sufficient adhesive performance as a pressure-sensitive adhesive tape used for fixing parts. Comparative Example 2, in which the softening point of the tackifier resin (C) was outside the range of the present invention, lacked tack and could not be used for measurement. Both Comparative Example 3, in which the kinematic viscosity (40°C) of the thermoplastic resin (B) was outside the range of the present invention, and Comparative Example 4, in which the softening point of the tackifier resin (C) was outside the range of the present invention, exhibited poor removability.

Claims

1. The composition contains at least a styrene-based block copolymer (A) having a farnesene structure, a thermoplastic resin (B), and a tackifier resin (C), The thermoplastic resin (B) has a kinematic viscosity (40°C) of 150 mm ２ / s or more 200,000mm ２ / s or less, or the number average molecular weight (Mn) is 450 or more and 4000 or less, The softening point of the tackifier resin (C) is 100°C or higher, The hot melt pressure-sensitive adhesive composition contains 30 to 500 parts by mass of the tackifier resin (C) per 100 parts by mass of the styrene block copolymer (A).

2. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the styrene-based block copolymer (A) comprises a polymer block (A-1) comprising structural units derived from styrene and a polymer block (A-2) comprising structural units derived from farnesene.

3. The thermoplastic resin (B) has a kinematic viscosity (40°C) of 20,000 mm ２ / s or more 200,000mm ２ The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the composition has a number average molecular weight (Mn) of 1,000 or more and 4,000 or less.

4. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the styrene block copolymer (A) has a weight average molecular weight (Mw) of 10,000 to 500,000.

5. 3. The hot melt pressure-sensitive adhesive composition according to claim 2, wherein the content of the polymer block (A-1) in the total amount of the styrene block copolymer (A) is 35 mass % or less.

6. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, comprising 5 to 300 parts by mass of the thermoplastic resin (B) per 100 parts by mass of the styrene block copolymer (A).

7. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein the thermoplastic resin (B) is a liquid at 23°C.

8. The hot melt pressure-sensitive adhesive composition according to claim 1 , wherein the thermoplastic resin (B) contains an olefin resin.

9. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, wherein a 40 μm thick pressure-sensitive adhesive layer obtained from the hot melt pressure-sensitive adhesive composition has a haze of 10% or less.

10. Storage modulus G' at 180°C is 5 x 10 ３ The hot melt pressure-sensitive adhesive composition according to claim 1, wherein:

11. The hot melt pressure-sensitive adhesive composition according to claim 1, having a biomass content of 30% or more.

12. 2. The hot melt pressure-sensitive adhesive composition according to claim 1, further comprising one or more additives selected from the group consisting of antioxidants, ultraviolet absorbers, heat stabilizers, and resin strengtheners.

13. A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer made of the hot melt pressure-sensitive adhesive composition according to any one of claims 1 to 12.

14. An article using the adhesive tape according to claim 13.

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