Hot melt composition and sealing material

Abstract

To provide a hot melt composition containing a biomass component excellent in flexibility under a low temperature environment while maintaining workability and heat resistance, and a sealing material.SOLUTION: 50 to 1000 parts by mass of a tackifier (B) and 500 to 2000 parts by mass of a non-aromatic softener (C) containing a biomass-derived non-aromatic softener (C1) in a proportion of 10 to 100% by mass based on 100 parts by mass of a hydrogenated styrene-based elastomer (A) having a weight-average molecular weight of 150000 to 600000, the hydrogenated styrene-based elastomer (A) having styrene-based polymer blocks at both ends and a hydrogenated diene polymer block in the middle part.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hot melt composition suitable for use as a hot melt sealant, and more particularly to a hot melt composition and sealant containing a biomass component that are excellent in flexibility in low-temperature environments and also excellent in ease of dismantling. [Background technology]

[0002] In recent years, in various industrial fields such as automobiles, electrical and electronics, construction, and civil engineering, the technique of joining (sealing) components used in assembly with hot melt adhesives has become widely used. When components are joined using such hot melt compositions, from the viewpoint of effective resource utilization and environmental protection, it is desirable that the components be easily separable when the product is disassembled after use, that is, that the components have excellent disassembly (or separability) properties so that the components can be easily recycled.

[0003] In Patent Document 1, a hot melt composition with excellent ease of disassembly is prepared by adding a styrene-based thermoplastic elastomer (SEEPS) having a kinematic viscosity of 200 to 1000 mm at 40°C. 2 A composition has been proposed in which paraffin oil having a softening point of 100°C or higher and an aromatic petroleum resin having a softening point of 100°C or higher are blended.

[0004] Patent Document 2 proposes a hot melt composition with excellent sealing and dismantling properties for polyolefins, which is a composition formulated with SEEPS having a weight average molecular weight of 250,000 or more, a terpene phenol resin having a hydroxyl value of 20 to 200 (mgKOH / g), and a hydrocarbon-based plasticizer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6634044 [Patent Document 2] Patent No. 4918845 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional hot melt compositions have been required to have heat resistance, but in recent years, there has been an increasing demand for hot melt compositions to have cold resistance, as measured in a thermal cycle test.

[0007] Furthermore, from the perspective of environmental measures, reducing carbon dioxide emissions has become a global challenge as part of measures to combat global warming. One way to reduce carbon dioxide emissions is to use raw materials derived from plants or similar microorganisms that absorb and assimilate carbon dioxide instead of conventional fossil-derived raw materials, so that even if the material is burned at the time of disposal, the amount of carbon dioxide released will not increase, which is known as carbon neutralization. Basic research toward this goal is also progressing, but when it comes to hot melt compositions in particular, there has been little material development.

[0008] The hot melt composition of Patent Document 1 has not been evaluated for its flexibility in low-temperature environments. Therefore, its flexibility in low-temperature environments is insufficient. Furthermore, although the hot melt composition uses a terpene resin, which is a biomass raw material, the rest of the composition is made up of petroleum-derived raw materials, making it difficult to increase the biomass content.

[0009] The hot melt composition of Patent Document 2 has not been evaluated for its flexibility in low-temperature environments. Therefore, its flexibility in low-temperature environments is insufficient. Furthermore, although the hot melt composition uses terpene phenol resin, which is a biomass raw material, the rest of the composition is made up of petroleum-derived raw materials, making it difficult to increase the biomass content.

[0010] The present invention was completed under these circumstances, and an object of the present invention is to provide a hot melt composition containing a biomass component that maintains workability and heat resistance while exhibiting excellent flexibility in low-temperature environments. Another object of the present invention is to provide a hot melt sealant that exhibits excellent sealing properties in low-temperature environments and is also easily dismantled. [Means for solving the problem]

[0011] As a result of extensive research aimed at solving the problems in the prior art, the present inventors discovered that blending a tackifying resin and a biomass-derived non-aromatic softener in a specific ratio with a hydrogenated styrene-based thermoplastic elastomer is effective, leading to the completion of the present invention.

[0012] Thus, according to the present invention, the following inventions are provided. (1) A hot melt composition containing 50 to 1,000 parts by mass of a tackifying resin (B) and 500 to 2,000 parts by mass of a non-aromatic softener (C) containing a biomass-derived non-aromatic softener (C1) in a proportion of 10 to 100% by mass per 100 parts by mass of a hydrogenated styrenic thermoplastic elastomer (A) having a weight-average molecular weight of 150,000 to 600,000, the elastomer having styrenic polymer blocks at both ends and a hydrogenated diene polymer block in the middle. (2) The hot melt composition according to (1), wherein the thermoplastic elastomer (A) is at least one selected from a styrene-ethylene-propylene-styrene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, or a styrene-ethylene-ethylene-propylene-styrene block copolymer. (3) The hot melt composition according to (1) or (2), wherein the softening point of the tackifier resin (B) is 100 to 160°C. (4) The hot melt composition according to any one of (1) to (3), wherein the tackifier resin (B) contains a tackifier resin derived from biomass. (5) The hot melt composition according to any one of (1) to (4), wherein the biomass content of the composition calculated from the weight ratio of biomass-derived raw materials is 20% or more. (6) The hot melt composition according to any one of (1) to (5), wherein the hydrogenated styrene-based thermoplastic elastomer (A) contains 10 to 50% by mass of a styrene-based polymer block. (7) The kinematic viscosity of the non-aromatic softener (C) at 40°C is 10 to 1,000 mm 2 The hot melt composition according to any one of (1) to (6), wherein the viscosity is 1 / s. (8) 50% compressive stress at 20°C is 0.05 kgf / cm 2 Above, 0.8kgf / cm 2 Less than 0.05kgf / cm2 at 50% compressive stress at -30℃ 2 Over 5.0kgf / cm 2 The hot melt composition according to any one of (1) to (7), wherein the hot melt composition is less than 100 wt %. (9) The hot melt composition according to any one of (1) to (8), which has a tensile elongation of 900% or more at -30°C. (10) The hot melt composition according to any one of (1) to (9), having a melt viscosity at 220°C of 5,000 to 200,000 mPa·s. (11) The hot melt composition according to any one of (1) to (10), wherein the permanent deformation at 50% compression at 80°C is less than 50%. (12) A sealing material comprising the hot melt composition according to any one of (1) to (11). [Effects of the Invention]

[0013] According to the present invention, a hot melt composition can be provided that maintains workability and heat resistance while exhibiting excellent flexibility in low-temperature environments. Furthermore, a sealing material using the hot melt composition of the present invention can be provided that exhibits excellent sealing properties in low-temperature environments and also exhibits excellent ease of disassembly. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art or those that are substantially the same.

[0015] The hot melt composition of the present invention contains, as essential components, 50 to 1,000 parts by mass of a tackifying resin (B) and 500 to 2,000 parts by mass of a non-aromatic hydrocarbon softener (C) per 100 parts by mass of a hydrogenated styrenic thermoplastic elastomer (A) having styrene polymer blocks at both ends and a hydrogenated diene polymer block in the middle, and having a weight-average molecular weight of 150,000 to 600,000, and the elastomer (A) contains styrene polymer blocks at both ends and a hydrogenated diene polymer block in the middle, and the component (C) contains 10 to 100% by mass of a biomass-derived non-aromatic softener (C1).

[0016] <Hydrogenated styrene-based thermoplastic elastomer (A)> The hydrogenated styrene-based thermoplastic elastomer used as component (A) in the present invention has styrene-based polymer blocks at both ends and a hydrogenated diene polymer block in the middle, and has a weight-average molecular weight (Mw) of 150,000 to 600,000. In the present invention, if the weight-average molecular weight of the hydrogenated styrene-based thermoplastic elastomer is too low, it will lack heat resistance as a sealing material, while if it is too high, it will have high melt viscosity when used as a hot-melt composition, making it difficult to dispense. The weight-average molecular weight is preferably 200,000 to 550,000, and more preferably 250,000 to 500,000. In the present invention, the weight-average molecular weight of the hydrogenated styrene-based thermoplastic elastomer is a standard polystyrene-equivalent value measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0017] The hydrogenated styrene-based thermoplastic elastomer (A) is an ABA-type triblock polymer consisting of a (styrene-based polymer block)-(hydrogenated diene-based polymer block)-(styrene-based polymer block), and can be obtained by selectively hydrogenating the diene-based polymer block (block B) of an AB'-A-type triblock copolymer (A is the styrene-based polymer block, and B' is the diene-based polymer block) using a known method. The monomer used to produce the styrene-based polymer block (block A) is an aromatic vinyl compound, specific examples of which include styrene, α-methylstyrene, vinyltoluene, and isopropenyltoluene. Of these, styrene is the most preferred. The monomer used to produce the diene polymer block (block B') is a conjugated diene having 4 to 5 carbon atoms, specific examples of which include 1,3-butadiene, isoprene, and 1,3-pentadiene. Of these, 1,3-butadiene, isoprene, or a mixture thereof is preferred.

[0018] The hydrogenated styrene-based thermoplastic elastomer (A) preferably contains 10 to 50% by mass of styrene-based polymer blocks and 90 to 50% by mass of hydrogenated diene polymer blocks in order to balance flexibility and heat resistance, and particularly preferably contains 20 to 40% by mass of styrene-based polymer blocks and 80 to 60% by mass of hydrogenated diene polymer blocks. The styrene-based polymer blocks at both ends usually have approximately the same molecular weight, but they do not necessarily have to be the same.

[0019] The hydrogenated diene polymer block (Block B) sandwiched between two styrene polymer blocks is formed by hydrogenating the carbon-carbon double bonds contained in the diene polymer. The higher the hydrogenation rate, the fewer unsaturated bonds there are, resulting in improved thermal stability and weather resistance of the polymer. However, complete hydrogenation is difficult in production, so it is sufficient if at least 50% or more, preferably 70% or more, is hydrogenated.

[0020] Specific examples of the hydrogenated styrene-based thermoplastic elastomer (A) include SEBS, which is a hydrogenated styrene-butadiene-styrene triblock copolymer (SBS), SEPS, which is a hydrogenated styrene-isoprene-styrene triblock copolymer (SIS), and SEEPS, which is a hydrogenated styrene-isoprene / butadiene-styrene triblock copolymer (SIBS). Specific examples of SEPS include Septon 2005 (trade name, manufactured by Kuraray Co., Ltd., styrene polymer block content (hereinafter referred to as styrene content) 20% by mass) and Septon 2006 (trade name, manufactured by Kuraray Co., Ltd., styrene content 35% by mass). Specific examples of SEBS include Kraton G1651 (trade name, manufactured by Kraton Polymers Co., Ltd., styrene content 33% by mass) and Septon 8006 (trade name, manufactured by Kuraray Co., Ltd., styrene content 33% by mass). Specific examples of SEEPS include Septon 4055 (trade name, manufactured by Kuraray Co., Ltd., styrene content 30% by mass), Septon 4077 (trade name, manufactured by Kuraray Co., Ltd., styrene content 30% by mass), and Septon 4099 (trade name, manufactured by Kuraray Co., Ltd., styrene content 30% by mass). Of these, SEEPS is preferably used because of its ability to retain non-aromatic hydrocarbon softeners and high tensile strength. Therefore, the hydrogenated styrene-based thermoplastic elastomer used as component (A) preferably contains 50% by mass or more, and even 80% by mass or more, of SEEPS, and particularly preferably contains only SEEPS. The hydrogenated butadiene-isoprene copolymer forming the intermediate block of SEEPS generally contains 10 to 90% by mass, preferably 30 to 70% by mass, of butadiene-derived units, and 90 to 10% by mass, preferably 70 to 30% by mass, of isoprene-derived units.

[0021] The hydrogenated styrene-based thermoplastic elastomer may be modified with a polar compound such as maleic anhydride, acrylic acid, methacrylic acid, a hydroxyl group, or phenol, or may be of the ABABA type (A represents a styrene-based polymer block and B represents a hydrogenated diene-based polymer block), which has a styrene-based polymer block at both ends as well as in the middle.

[0022] <Tackifying resin (B)> In the present invention, the tackifier resin used as component (B) preferably has a softening point of 100 to 160°C, and more preferably 110 to 155°C. If the softening point is below the lower limit, heat resistance becomes insufficient. Conversely, if the softening point is above the upper limit, the softening point of the composition increases, necessitating a higher application temperature when used as a hot-melt composition, which reduces energy efficiency and causes the composition to deteriorate due to heat during application. In the present invention, the softening point of the tackifier resin is a value measured in accordance with JAI-7-1997.

[0023] The tackifying resin used as component (B) may be a single resin, or, if necessary, a combination of two or more resins. In addition, both biomass-derived and petroleum-derived tackifying resins are suitable. The amount of component (B) used is 50 to 1,000 parts by mass, preferably 100 to 800 parts by mass, per 100 parts by mass of component (A). If the content of component (B) is too low, the melt viscosity increases, impairing workability. Conversely, if the content is too high, the melt viscosity decreases, impairing workability and also resulting in a problem of reduced flexibility of the compound in low-temperature environments.

[0024] The tackifying resin used is not particularly limited as long as it is one that has conventionally been used in hot melt compositions having a thermoplastic styrene-based elastomer as the base polymer, and examples thereof include rosin-based resins such as gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin, rosin glycerin ester, and hydrogenated rosin glycerin ester; and biomass-derived tackifying resins typified by terpene resins (α-pinene-based, β-pinene-based, dipentene-based, etc.), hydrogenated terpene resins, aromatic hydrocarbon-modified terpene resins, hydrogenated aromatic hydrocarbon-modified terpene resins, terpene-phenol copolymer resins, and hydrogenated terpene-phenol copolymer resins. Other examples include alicyclic resins such as dicyclopentadiene resins and hydrogenated dicyclopentadiene resins; aliphatic hydrocarbon resins such as C5 hydrocarbon resins, hydrogenated C5 hydrocarbon resins, C5 / C9 hydrocarbon resins and hydrogenated C5 / C9 hydrocarbon resins; and petroleum-derived tackifying resins typified by aromatic resins having ethylenic carbon-carbon double bonds such as styrene resins, α-methylstyrene resins and C9 resins.

[0025] Specifically, Endex 155 (trade name, manufactured by Synthomer Co., Ltd., softening point 153°C), Kristalex 5140 (trade name, manufactured by Synthomer Co., Ltd., softening point 139°C), FTR 2140 (trade name, manufactured by Mitsui Chemicals, Inc., softening point 137°C), Sylvares SA 140 (trade name, manufactured by Kraton Polymers, Inc., softening point 140°C), and FMR 0150 (trade name, manufactured by Mitsui Chemicals, Inc., softening point 145°C). , SkyrezN140 (trade name, manufactured by Sky Chemical Co., Ltd., softening point 140°C), Imarv P140 (trade name, manufactured by Idemitsu Kosan Co., Ltd., softening point 140°C), Imarv P125 (trade name, manufactured by Idemitsu Kosan Co., Ltd., softening point 125°C), Imarv P100 (trade name, manufactured by Idemitsu Kosan Co., Ltd., softening point 100°C), Alcon P140 (trade name, manufactured by Arakawa Chemical Co., Ltd., softening point 140°C), Alcon P125 (trade name, manufactured by Arakawa Chemical Co., Ltd. softening point 125°C), Alcon P100 (trade name, manufactured by Arakawa Chemical Industries, softening point 100°C), Rigalite R1125 (trade name, manufactured by Synthomer Corporation, softening point 125°C), ECR5340 (trade name, manufactured by Exxon Mobil Corporation, softening point 140°C), ECR5320 (trade name, manufactured by Exxon Mobil Corporation, softening point 125°C), ECR5300 (trade name, manufactured by Exxon Mobil Corporation, softening point 105°C), T-REZ OP501 (trade name, manufactured by ENEOS Corporation, softening point 138°C), T-REZ HA125 (trade name, manufactured by ENEOS Corporation, softening point 125°C), T-REZ Examples include HA105 (trade name, manufactured by ENEOS Corporation, softening point 105°C), YS Resin PX1250 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 125°C), YS Resin PX1150 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 115°C), YS Resin PX1000 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 100°C), Clearon P150 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 150°C), Clearon P125 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 125°C), and Clearon P100 (trade name, manufactured by Yasuhara Chemical Co., Ltd., softening point 100°C).

[0026] <Non-aromatic softener (C)> In the present invention, a non-aromatic softener is used as component (C). Here, "non-aromatic softener" refers to a softener that is substantially free of aromatic components. Aromatic softeners, which contain a large amount of aromatic compounds, are undesirable because they are incorporated into the styrene blocks of the thermoplastic styrene-based elastomer, impairing heat resistance. Therefore, aromatic softeners are excluded from component (C). However, softeners containing small amounts of aromatic compounds, such as naphthenic softeners, may contain small amounts of aromatic compounds as long as the effects of the present invention are not substantially impaired. In this case, the upper limit is 5% by mass or less, and particularly 2% by mass or less.

[0027] The non-aromatic softener used as component (C) is blended to adjust the melt viscosity of the composition and impart flexibility, and is used in a ratio of 500 to 2,000 parts by mass, preferably 600 to 1,800 parts by mass, per 100 parts by mass of component (A). If the blending amount of component (C) is too small, flexibility will be impaired, while if it is too large, heat resistance will tend to decrease. In addition, component (C) is a softener having a kinematic viscosity of 10 mm at 40°C. 2 / s or more is preferable, and 20 mm 2 / s or more is more preferable. When a softener having a kinematic viscosity below this range is used, the melt viscosity of the composition is reduced, but the heat resistance is likely to decrease. The upper limit of the kinematic viscosity at 40°C of the non-aromatic softener is preferably 1,000 mm 2 / s or less, preferably 800mm 2 / s or less, and 500 mm 2 In the present invention, the kinematic viscosity of the softener is a value measured in accordance with the ASTM D445 standard, the JIS K2283 standard, or a measurement method equivalent thereto.

[0028] The non-aromatic softener (C) may be a biomass-derived non-aromatic softener (C1) used alone or in combination as needed. In the present invention, the proportion of component (C1) in component (C) is 10% by mass or more, preferably 15% by mass or more. Without component (C1), flexibility in low-temperature environments cannot be sufficiently improved. Furthermore, the inclusion of component (C1) increases the biomass content of the composition. Furthermore, a petroleum-derived non-aromatic softener (C2) can be used as part of component (C) to the extent that flexibility and workability in low-temperature environments are not impaired. The ratio of component (C1) to component (C2) used is 10 to 100% by mass, preferably 15 to 95% by mass, based on the total amount of both, with component (C1) accounting for 10 to 100% by mass, preferably 15 to 95% by mass, and component (C2) accounting for 90 to 0% by mass, preferably 85 to 5% by mass.

[0029] The biomass-derived non-aromatic softener used as component (C1) can be used without any particular limitation as long as it satisfies the kinematic viscosity range of component (C) and is derived from biomass. The kinematic viscosity at 40°C of the biomass-derived non-aromatic softener (C1) is 10 mm 2 / s or more 1000mm 2 / s or less is preferable, and 15 mm 2 / s or more 800mm 2 / s or less, 20 mm 2 / s or more 600mm 2 / s or less, 25 mm 2 / s or more 400mm 2 / s or less, 30 mm 2 / s or more 200mm 2 Specific examples of the component (C1) include VIVA-B-FIX 10227 (trade name, manufactured by H&R, kinematic viscosity at 40°C: 58 mm 2 / s), VIVA-B-FIX10229 (trade name, manufactured by H&R, kinematic viscosity at 40°C: 21 mm 2 / s) are some examples.

[0030] There are no particular restrictions on the biomass components that can be used to produce component (C1). Specific examples include unused biomass components such as inedible parts of agricultural crops and forest residues, waste biomass components such as food waste, livestock excrement, construction waste, and waste paper, resource grains, which are plants cultivated for the purpose of being used as energy sources or raw materials for products, and new crops such as marine plants and newly genetically modified plants suitable for biomass production.

[0031] The petroleum-derived non-aromatic softener used as component (C2) can be any softener that satisfies the kinematic viscosity range of the above-mentioned component (C) and has been conventionally used in hot melt compositions using thermoplastic styrene-based elastomers as the base polymer, without any particular limitations. The kinematic viscosity at 40°C of the petroleum-derived non-aromatic softener (C2) is 10 mm 2 / s or more 1000mm 2 / s or less is preferable, and 20 mm 2 / s or more 800mm 2 / s or less, 30 mm 2 / s or more 600mm 2 / s or less, 40 mm 2 / s or more 500mm 2 / s or less, 50 mm 2 / s or more 400mm 2 / s or less. Examples of the (C2) component include paraffinic or naphthenic process oils; liquid polymers such as liquid polybutene, liquid polybutadiene, and liquid polyisoprene; hydrocarbon oils such as liquid paraffin and olefin process oil; and the like.

[0032] Specifically, Diana Process Oil PW-380 (trade name, manufactured by Idemitsu Kosan Co., Ltd., kinematic viscosity at 40°C: 382 mm 2 / s), Diana Process Oil PW-90 (trade name, manufactured by Idemitsu Kosan Co., Ltd., kinematic viscosity at 40°C: 95 mm 2 / s), Diana Process Oil PX-380 (trade name, manufactured by Idemitsu Kosan Co., Ltd., kinematic viscosity at 40°C: 508 mm 2 / s), KP6025 (trade name, manufactured by Henan Runhua Chemicals Co., Ltd., kinematic viscosity at 40°C: 394 mm 2 / s), KP6030 (trade name, manufactured by Henan Runhua Chemicals Co., Ltd., kinematic viscosity at 40°C: 466 mm 2 / s), PIONIER2275 (product name, manufactured by H&R, 40℃ kinematic viscosity: 374.4mm 2 Paraffin-based process oil such as Lucant HC-40 (trade name, manufactured by Mitsui Chemicals, Inc., kinematic viscosity at 40°C: 380 mmHg) 2 / s), DURASYN174 (product name, manufactured by INEOS Capital Ltd., kinematic viscosity at 40℃: 412mm 2 / s), SpectraSyn40 (trade name, manufactured by ExxonMobil Corporation, 40°C, mobility: 396 mm 2 Among them, paraffin-based process oils are preferably used in view of compatibility with the base polymer and heat resistance.

[0033] <Other compounding agents (D)> In the present invention, in addition to the above components (A) to (C), compounding ingredients (D) such as elastomer components other than component (A), antioxidants, ultraviolet absorbers, fillers, silane coupling agents, pigments, dyes, antistatic agents, flame retardants, stabilizers, solvents, and antifoaming agents that are commonly used in the technical field of hot melt compositions using thermoplastic styrene elastomers as base polymers may be compounded as needed.

[0034] Examples of elastomer components other than component (A) include hydrogenated ABA styrenic thermoplastic elastomers having a weight-average molecular weight of less than 150,000, AB'-A styrenic thermoplastic elastomers in which the diene polymer block is not hydrogenated, AB styrenic thermoplastic elastomers, AB' styrenic thermoplastic elastomers in which the diene polymer block is not hydrogenated, etc. These components may be contained in the composition to the extent that they do not essentially impair the effects of the present invention, but if the amount is too large, heat resistance and weather resistance will be deteriorated, so the amount should preferably be 5% by mass or less, or even 3% by mass or less, of the composition, and it is most preferable that these components are not contained at all.

[0035] Examples of primary antioxidants include naphthylamines, p-phenylenediamines, quinolines, phenols, hindered phenols, and hindered amines, with hindered phenols being preferred. Examples of secondary antioxidants include phosphites, thioethers, and hydroxylamines, with phosphites being preferred. From the standpoint of antioxidant effect and thermal stability of the composition, the content of the primary antioxidant and secondary antioxidant is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of component (A).

[0036] Examples of UV absorbers include benzotriazoles, triazines, benzophenones, and cyanoacrylates, with benzotriazoles being preferred. From the viewpoint of weather resistance of the composition, the content of the UV absorber is preferably 1 to 30 parts by mass, particularly 2 to 20 parts by mass, per 100 parts by mass of component (A1). Conventional fillers can be used, including inorganic or organic fillers of various shapes. Adding a filler can strengthen the cured product and provide excellent adhesion to, for example, mortar and metals. Examples of inorganic fillers include calcium carbonate, zinc oxide, glass beads, titanium oxide, alumina, carbon black, clay, ferrite, talc, mica powder, aerosil, silica, and inorganic fibers such as glass fiber, as well as inorganic foams. Examples of organic fillers include powders of thermosetting resins such as epoxy resins, carbon fibers, synthetic fibers, and synthetic pulp.

[0037] Examples of silane coupling agents include trimethoxyvinylsilane and γ-glycidoxypropyltrimethoxysilane, and their incorporation improves adhesion to wet surfaces. Examples of pigments include inorganic pigments such as titanium oxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, and sulfate; and organic pigments such as Neozabon Black RE, Neo Black RE, Orasol Black CN, and Orasol Black Ba (all manufactured by Ciba-Geigy), and Spiron Blue 2BH (manufactured by Hodogaya Chemical Co., Ltd.), which can be used in combination as needed.

[0038] Dyes such as black, yellow, red, blue, and brown dyes are used depending on the desired color of the product. Antistatic agents include hydrophilic compounds such as quaternary ammonium salts, polyglycols, and ethylene oxide derivatives. Flame retardants include chloroalkyl phosphates, dimethyl methyl phosphonates, bromine-phosphorus compounds, ammonium polyphosphates, neopentyl bromide polyethers, and brominated polyethers. Stabilizers include fatty acid silyl esters and fatty acid amide trimethylsilyl compounds. Antifoaming agents include calcium oxide, magnesium oxide, and molecular sieves.

[0039] <Hot melt composition> The method for producing the hot-melt composition of the present invention is not particularly limited and can be produced by conventionally known methods. For example, the hot-melt composition can be obtained by adding each of the components (A) to (C) and any other components that are optionally added to a kneader heated to a temperature close to the melting point of the components and thoroughly melt-mixing them. Examples of kneaders include Banbury mixers equipped with a heating device and a degassing device, pressure kneaders, Henschel mixers, Brabender kneaders, and dispersers. The pressure inside the kneader can be reduced as needed. The procedure for kneading the components is not particularly limited and may involve either adding all the components at once and kneading them together, or pre-kneading component (A) and a portion of the other components and then adding the remaining components and kneading them together. The hot-melt composition thus obtained can be stored, for example, in a release box, a pail, or a drum.

[0040] The softening point of the hot melt composition of the present invention is usually 130 to 240°C, and preferably 150 to 200°C. If the softening point is too low, the heat resistance will be insufficient, and conversely, if the softening point is too high, the meltability will decrease. In the present invention, the softening point of the hot melt composition is a value measured in accordance with JAI-7-1997.

[0041] The melt viscosity of the hot melt composition varies depending on the measurement temperature, but from the viewpoint of workability during application, a melt viscosity of 5,000 to 200,000 mPa·s, particularly 10,000 to 150,000 mPa·s at 220°C is preferred. In the present invention, the melt viscosity of the hot melt composition is a value measured at 220°C using a Brookfield automatic viscometer (model: BROOKFIELD RVDV2T).

[0042] The hot melt composition has a 50% compressive stress of 0.05 kgf / cm at 20°C. 2 Above 0.8kgf / cm 2 Below that, even 0.06kgf / cm 2 Above 0.7kgf / cm 2 Below, especially 0.07kgf / cm 2 Above 0.6kgf / cm 2 It is preferable that the elastic modulus is 0.05 kgf / cm or less in order to improve flexibility and dismantling ability, and the elastic modulus is 0.05 kgf / cm or less at -30°C. 2 Above 5.0kgf / cm 2 Below, especially 0.1kgf / cm 2 Above 4.5kgf / cm 2 In addition to this, a tensile elongation of 900% or more, particularly 1,000% or more at -30°C is preferred for excellent flexibility and improved sealing properties in low-temperature environments. Furthermore, a compression set of less than 50%, particularly less than 45%, at 80°C is appropriate for excellent heat resistance and ensuring sealing properties.

[0043] In this embodiment, the biomass degree of the hot melt composition, calculated from the weight ratio of the biomass-derived components, is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more. By setting the biomass degree within the above range, carbon dioxide emissions can be suppressed, contributing to a reduction in the environmental load. The biomass degree of the hot melt composition and its constituent components can be calculated using the following method. Biomass ratio of constituents [%] = (total dry mass of plant-derived components / total dry mass of raw materials) x 100 Biomass content of hot melt composition [%] = Σ (biomass content of constituent components × mass%)

[0044] The substrates to which the hot melt composition of the present invention can be applied, i.e., adhesive members and adherends, are not particularly limited, and examples thereof include polyolefins such as polyethylene, polypropylene, polybutene, and polystyrene; engineering plastics such as polycarbonate, polyester, polyamide, and polyacetal; metals, glass, and rubber.

[0045] The uses of the hot melt composition of the present invention are not particularly limited, and it can be used for applications such as bonding and sealing of automobiles and vehicles (bullet trains and electric trains), electrical appliances, building materials, woodworking, bookbinding and packaging, etc. Automotive-related applications include bonding of interior materials such as ceilings, doors, and seats, and bonding and sealing of exterior materials such as automotive lighting fixtures such as lamps and side moldings. Electrical-related applications include the assembly of lampshades, speakers, etc. Building material and woodworking-related applications include bonding of doors, access floors, multi-layer floors, furniture assembly, edge bonding, profile wrapping, etc. at construction sites and in the manufacturing of building materials.

[0046] <Sealing material> The sealing material of the present invention is obtained by using the above-mentioned hot melt composition and is generally called a gasket, packing, sealing, caulking, putty, etc. The shape of the sealing material is not particularly limited, and it may be in any shape such as pellets, powder, strings, or strips. The use of the sealing material is not particularly limited, but it can be suitably used, for example, as a sealing material for components, equipment, and vehicles used in cold regions or low-temperature environments such as freezer and refrigerated warehouses.

[0047] The sealing method using the sealing material of the present invention is not particularly limited, and may be carried out in accordance with a conventional method.

[0048] Hot melt compositions are typically applied automatically or manually to the surfaces of components that require sealing using a heating and application device known as an applicator. The heating and application device is a device capable of drawing up a fixed amount of molten hot melt composition using a gear pump or the like, and is used by heating the composition appropriately according to the softening point of the hot melt composition. The application form of the hot melt composition is not particularly limited, but the hot melt composition is typically applied to the components to be sealed under heating. Subsequently, another component is brought into contact with the component to which the hot melt composition has been applied and mechanically fastened, thereby forming a component with a sealed joining surface.

[0049] In addition to the method of forming a loop by heat application to a component, a loop-shaped gasket can be prepared in advance and then attached to the joining surface automatically or manually. Such a gasket can be made by preparing release paper or a polytetrafluoroethylene release film, and then applying the hot melt composition to the prepared surface by heat application in a predetermined shape.

[0050] When it becomes necessary to replace assembled components or to disassemble and separate a used product, this can be done as follows: Because the sealing material of the present invention has excellent dismantling properties, it can be easily removed simply by releasing the restraints on the mechanically fastened parts, without using removal tools such as industrial dryers or plastic bars that heat and reduce the viscosity of the sealing material as in the past.

[0051] In this case, the sealing material used in the gap between the components has a repulsive force against the respective contact surfaces, and can be easily peeled off without leaving any residual sealing material on the contact surfaces. In this way, when the sealing material of the present invention is used, components can be easily removed without requiring special dismantling tools, as in the case of using a molded gasket.

[0052] As described above, the hot melt composition of the present invention has excellent performance in that it combines flexibility in low-temperature environments with workability and heat resistance. Furthermore, a sealing material prepared from the hot melt composition combines both sealing properties between components and ease of disassembly, and has excellent flexibility in low-temperature environments. Furthermore, when the biomass content is high, it can be carbon-neutral, thereby reducing the environmental impact. [Example]

[0053] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified. The physical properties of the components used in the blending and the hot melt composition were evaluated as follows:

[0054] (1) Melt viscosity: Measurement was performed using an automatic viscometer manufactured by Brookfield (model: BROOKFIELD RVDV2T) at 220° C. The spindle No. of the automatic viscometer used for the measurement was No. 29, and the rotation speed was set to 5 rpm. (2) 50% compressive stress: The molten hot melt composition was poured into a cylindrical metal container and formed into a cylindrical shape with a height of 20 mm and a diameter of 27 mm, which was used as a test sample. The test sample was left to stand for at least 1 hour in a precision universal testing machine set at temperatures of 20°C and -30°C, and then the stress (kgf / cm) when the test sample was compressed 50% in the height direction of the cylinder at a speed of 50 mm / min was measured. 2 The 50% compressive stress was measured by multiplying the measured value by the cylinder base area (5.72 cm 2 ) was calculated by dividing by (3) Tensile elongation: The hot-melt composition was processed into a 2 mm thick sheet using a heat press and molded into a strip with a short side of 10 mm and a long side of 50 mm, which was used as a test sample. After the test sample was left to stand for at least 1 hour in a vertical testing machine set at -30°C, both ends of the long side, 15 mm long, were clamped with a jig, and the remaining 20 mm was used as the test part. The test sample was then pulled at a pulling speed of 500 mm / min to measure the elongation (%) at break. (4) Compression set: The molten hot melt composition was poured into a cylindrical metal container and molded into a columnar shape with a height of 20 mm and a diameter of 27 mm, which was used as a test sample. The test sample was compressed 50% in the height direction (displacement of 10 mm) and left to stand in an environment at 80°C for 24 hours. After 24 hours, the compression was released and the sample was left to stand in an environment at 20°C for 24 hours. The height of the column was then measured, and the compression set was calculated according to the following formula. Compression set (%) = {(initial height - height after storage) / displacement} x 100

[0055] Example 1 As the (A) component, (A1) Septon 4055 (trade name, manufactured by Kuraray Co., Ltd., SEEPS, weight average molecular weight 300,000, styrene content 30%, biomass content 0%) 100 parts, as the (B) component, (B1) Endex 155 (trade name, manufactured by Synthomer Co., Ltd., styrene-based tackifying resin, softening point 153°C, biomass content 0%) 100 parts, (B2) T-REZ HA125 (trade name, manufactured by ENEOS Corporation, hydrogenated alicyclic tackifying resin, softening point 125°C, biomass content 0%) 200 parts, as the (C) component, (C1) VIVA-B-FIX 10227 (trade name, manufactured by H&R Co., Ltd., biomass-derived aliphatic oil, 40°C kinematic viscosity: 58mm 2 A hot-melt composition containing 850 parts of (D1) Irganox 1010 (trade name, manufactured by BASF, hindered phenol, biomass content 0%) as a primary antioxidant and 10 parts of (D1) Irganox 1010 (trade name, manufactured by BASF, hindered phenol, biomass content 0%) as a primary antioxidant was prepared by heating and mixing the components. The workability, flexibility, and heat resistance of the resulting composition were measured. The results are shown in Table 1.

[0056] Examples 2 to 20 and Comparative Examples 1 to 7 Hot melt compositions were prepared in the same manner as in Example 1, except that the compositions of components (A) to (C) were changed as shown in Table 1, and the resulting compositions were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0057] The materials used in the above Examples 2 to 20 and Comparative Examples 1 to 7 are as follows. (A2) Septon 4077 (trade name, manufactured by Kuraray Co., Ltd., SEEPS, weight average molecular weight 400,000, styrene content 30%, biomass content 0%) (A3) Kraton G1651 (trade name, manufactured by Kraton Polymers, SEBS, weight average molecular weight 270,000, styrene content 33%, biomass content 0%) (B3) YS Resin PX1250 (trade name, manufactured by Yasuhara Chemical Co., Ltd., terpene-based tackifying resin, softening point 125°C, biomass content 99%) (B4) Clearon P125 (trade name, manufactured by Yasuhara Chemical Co., Ltd., hydrogenated terpene-based tackifying resin, softening point 125°C, biomass content 99%) (B5) Clearon P150 (trade name, manufactured by Yasuhara Chemical Co., Ltd., hydrogenated terpene tackifying resin, softening point 150°C, biomass content 99%) (C1-2) VIVA-B-FIX 10229 (trade name, manufactured by H&R, biomass-derived non-aromatic softener, kinematic viscosity at 40°C: 21 mm 2 / s, biomass content 100%) (C2-1) Diana Process Oil PW-380 (trade name, manufactured by Idemitsu Kosan Co., Ltd., petroleum-derived non-aromatic softener, kinematic viscosity at 40°C: 382 mmHg) 2 / s, biomass content 0%) (C2-2) Diana Process Oil PX-380 (trade name, manufactured by Idemitsu Kosan Co., Ltd., petroleum-derived non-aromatic softener, kinematic viscosity at 40°C: 508 mmHg) 2 / s, biomass content 0%)

[0058] [Table 1]

[0059] [Table 2]

[0060] The results in Tables 1 and 2 show that the hot melt composition of the present invention exhibits excellent flexibility in a low-temperature environment, workability, and heat resistance.

[0061] In contrast, when only component (C2) was used as the non-aromatic softener (Comparative Examples 1 and 7), or when the blending amount of component (C1) was small (Comparative Example 2), the 50% compressive stress and elongation at −30° C. were insufficient. Furthermore, when the blending amounts of components (B) and (C) were outside the specified ranges (Comparative Examples 3, 4, 5, and 6), any of the melt viscosity, 50% compressive stress and elongation at −30° C., and compression set were insufficient. [Industrial Applicability]

[0062] The hot melt composition of the present invention has excellent flexibility in low-temperature environments and allows for easy separation of components during dismantling, making it suitable as a hot melt sealant for components used in low-temperature environments. It is also useful as a waterproof sealant for automotive parts, electrical appliances, and building materials that use plastics and metals as adherends. Furthermore, the use of materials derived from biomass raw materials can increase the biomass content and reduce environmental impact, which is expected to contribute to the increasing social demand for carbon neutrality in industry.

Claims

1. A hot melt composition containing 50 to 1,000 parts by mass of a tackifier resin (B) and 500 to 2,000 parts by mass of a non-aromatic softener (C) containing a biomass-derived non-aromatic softener (C1) in a proportion of 10 to 100% by mass per 100 parts by mass of a hydrogenated styrene-based thermoplastic elastomer (A) having a weight-average molecular weight of 150,000 to 600,000, the elastomer having styrene polymer blocks at both ends and a hydrogenated diene polymer block in the intermediate portion.

2. 2. The hot melt composition according to claim 1, wherein the thermoplastic elastomer (A) is at least one selected from a styrene-ethylene-propylene-styrene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, or a styrene-ethylene-ethylene-propylene-styrene block copolymer.

3. 3. The hot melt composition according to claim 1, wherein the softening point of the tackifier resin (B) is 100 to 160°C.

4. The hot melt composition according to claim 1 or 2, wherein the tackifier resin (B) comprises a biomass-derived tackifier resin.

5. 3. The hot melt composition according to claim 1, wherein the hot melt composition has a biomass content of 20% or more as calculated from the weight ratio of the biomass-derived raw material.

6. 3. The hot melt composition according to claim 1, wherein the hydrogenated styrene-based thermoplastic elastomer (A) contains 10 to 50% by mass of a styrene-based polymer block.

7. The non-aromatic softener (C) has a kinematic viscosity at 40°C of 10 to 1,000 mm 2 3. The hot melt composition according to claim 1, wherein the viscosity is 100 MPa or less.

8. 50% compressive stress at 20°C is 0.05 kgf / cm 2 Above, 0.8kgf / cm 2 Less than 0.05 kgf / cm2 at 50% compressive stress at -30°C 2 Above 5.0 kgf / cm 2 3. The hot melt composition according to claim 1, wherein the viscosity is less than 1000 MPa.

9. 3. The hot melt composition according to claim 1, wherein the tensile elongation at -30°C is 900% or more.

10. 3. The hot melt composition according to claim 1, wherein the melt viscosity at 220°C is 5,000 to 200,000 mPa·s.

11. 3. The hot melt composition according to claim 1, wherein the permanent deformation at 50% compression at 80°C is less than 50%.

12. A sealing material comprising the hot melt composition according to claim 1 or 2.

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