Adhesive compositions

Abstract

To provide an adhesive composition that not only has high initial strength but also sufficient strength over time, and that is resistant to shifting even at low temperatures. [Solution] An adhesive composition comprising component (A): copolymer component, component (B): tackifier component, and component (C): plasticizer component, The aforementioned component (A) comprises component (A1): styrene-butadiene-styrene block copolymer (SBS), component (A2): styrene-isoprene-styrene block copolymer (SIS), and component (A3): hydrogenated styrene block copolymer. An adhesive composition wherein the content of component (A3) in 100% by mass of component (A) is 35% by mass or more.

Description

Technical Field

[0001] The present invention relates to a composition for an adhesive.

Background Art

[0002] An absorbent article is, for example, an article that is fixed to clothing such as underwear or a body suit in order to absorb body fluids generated from the body such as menstrual blood, feces, urine, sweat, etc., and is used to prevent discomfort and non-hygiene caused by the adhesion of body fluids to clothing.

[0003] Examples of absorbent articles include menstrual pads, urine collection liners, maternity shorts, breast pads, sweat pads, paper diapers, pet sheets, hospital gowns, surgical gowns, etc. And such absorbent articles are provided with a positioning adhesive for fixing them to clothing and preventing them from shifting during use.

[0004] Many absorbent articles generally have a moisture-permeable topsheet that contacts the skin, a liquid-impermeable backsheet (generally a breathable polyethylene sheet) that contacts clothing such as underwear or a body suit, and an absorber sandwiched between them. The positioning adhesive for the absorbent article is generally coated on a release substrate and then transferred to the liquid-impermeable backsheet, and the absorbent article is adhered to and held at the desired position on the clothing by bringing the transferred positioning adhesive into contact with the clothing.

[0005] Many studies have been conducted so far on an adhesive (hereinafter also referred to as "anti-shift adhesive") for attaching such absorbent articles to underwear.

[0006] The anti-shift adhesive is required to have a strength for securely attaching the sanitary product to the underwear. On the other hand, when the strength of the adhesive is increased, there is a concern that glue residue is likely to remain on the underwear when the sanitary product is peeled off from the underwear. Also, when the strength of the adhesive is increased, there is a concern that the strength over time is likely to decrease due to the influence of heat or the like.

Summary of the Invention

[0007] In view of the above circumstances, the object of the present invention is to provide an adhesive composition that not only has high initial strength but also sufficient strength over time, and that is resistant to shifting even at low temperatures. [Means for solving the problem]

[0008] The inventors diligently conducted research to solve the above problems and found that the above problems can be solved by setting the content of the hydrogenated styrene block copolymer component to a predetermined level or higher in an adhesive composition containing a copolymer component, a tackifier component, and a plasticizer component. Based on this finding, the inventors conducted further research and completed the present invention.

[0009] In other words, the present invention provides the following adhesive compositions. Section 1. An adhesive composition comprising component (A): copolymer component, component (B): tackifier component, and component (C): plasticizer component, The aforementioned component (A) comprises component (A1): styrene-butadiene-styrene block copolymer (SBS), component (A2): styrene-isoprene-styrene block copolymer (SIS), and component (A3): hydrogenated styrene block copolymer. An adhesive composition wherein the content of component (A3) in 100% by mass of component (A) is 35% by mass or more. Section 2. The composition according to claim 1, wherein the content of component (A3) in 100% by mass of the total mass of component (A2) and component (A3) is 50% by mass or less. Section 3. The composition according to item 1 or 2, wherein the component (C) is paraffin oil, and the paraffin oil has a kinematic viscosity of 90 mPa·s or more at 40°C. Section 4. A composition according to any one of items 1 to 3, wherein the total mass of the aforementioned components (A1), (A2), and (A3) is 25% by mass or more of 100% by mass of the entire composition. Section 5. A composition according to any of items 1 to 4, wherein the softening point of component (B) is 90 to 110°C. Section 6. The composition contains 5 to 15% by mass of C5-C9 petroleum resin in 100% by mass of the total composition. The C5-C9 petroleum resin is a liquid at 23°C, and is one of the compositions of items 1 to 5. Section 7. A composition according to any of items 1 to 6, for positioning absorbent articles. [Effects of the Invention]

[0010] The adhesive composition according to the present invention, as described above, not only has high initial strength but also sufficient strength over time, and is resistant to shifting even at low temperatures. [Modes for carrying out the invention]

[0011] In this specification, "contains" is a concept that encompasses all of the following: "contains," "consist essentially of," and "consist of." Furthermore, in this specification, when a numerical range is indicated as "A~B," it means A or greater and B or less.

[0012] 1.Component (A): Copolymer component Component (A) is a copolymer component, comprising component (A1): styrene-butadiene-styrene block copolymer (SBS), component (A2): styrene-isoprene-styrene block copolymer (SIS), and component (A3): hydrogenated styrene block copolymer. Component (A) may also consist only of components (A1), (A2), and (A3).

[0013] Regarding the content of component (A) in the adhesive composition of the present invention, in order to prevent adhesive residue and decrease in strength over time, it is preferable that component (A) be present in an amount of 25% by mass or more, more preferably 27% by mass or more, and even more preferably 29% by mass or more, per 100% by mass of the adhesive composition. Furthermore, due to reasons such as insufficient strength and increased viscosity making coating difficult, it is preferable that component (A) be present in an amount of 32% by mass or less, more preferably 31% by mass or less, and even more preferably 30% by mass or less, per 100% by mass of the adhesive composition.

[0014] The above-mentioned SBS can be a commercially available product. Examples include Asahi Kasei Corporation's product names "Asapren T-438," "Asapren T-439," and "Asapren T-413." These can be used individually or in combination.

[0015] The above-mentioned SIS can be a commercially available product. Examples include "Quintac 3520," "Quintac SL-186," and "Quintac 3433N" from Zeon Corporation, and "D1161" from Kraton. These can be used individually or in combination.

[0016] A wide range of known hydrogenated styrene block copolymers can be used, and there are no particular limitations. Specifically, examples include styrene-ethylene-butylene-styrene (SEBS) copolymer, styrene-butylene-butadiene-styrene (SBBS) copolymer, styrene-ethylene-propylene-styrene (SEPS) copolymer, and styrene-ethylene-ethylene-propylene-styrene (SEEPS) copolymer. These may be used individually or in combination.

[0017] The above-mentioned SEBS can be commercially available products. Examples include Kraton's product names "G1726" and "G1645". These can be used individually or in combination.

[0018] The above-mentioned SBBS can use commercially available products. For example, product names such as "Tuftec P1500", "Tuftec P1083", "Tuftec P5051", etc. manufactured by Asahi Kasei Corporation can be mentioned. These can be used alone or in combination.

[0019] The above-mentioned SEPS can use commercially available products. For example, product names such as "SEPTON 2063", "SEPTON 2005", etc. manufactured by Kuraray Co., Ltd. can be mentioned. These can be used alone or in combination.

[0020] The above-mentioned SEEPS can use commercially available products. For example, product names such as "SEPTON 4033", "SEPTON 4055", etc. manufactured by Kuraray Co., Ltd. can be mentioned. These can be used alone or in combination.

[0021] In addition to the above-mentioned components (A1), (A2) and (A3), within the range that does not inhibit the effects and purposes of the present invention, known copolymer components may be appropriately used.

[0022] The content of component (A3) contained in component (A) is 35% by mass or more of component (A3) in 100% by mass of component (A). When the content of component (A3) in 100% by mass of component (A) is less than 35% by mass, the strength over time will decrease.

[0023] Also, the content of component (A3) in 100% by mass of component (A) is preferably 38% by mass or more, and more preferably 40% by mass or more. Also, the content of component (A3) in 100% by mass of component (A) is preferably 50% by mass or less, and more preferably 45% by mass or less in order to ensure sufficient initial adhesion strength.

[0024] The weight-average molecular weight (Mw) of component (A) is not particularly limited, but the diblock is preferably in the range of 25,000 to 150,000, more preferably in the range of 30,000 to 140,000, and the triblock is preferably in the range of 45,000 to 400,000, more preferably in the range of 50,000 to 350,000.

[0025] The weight-average molecular weight (Mw) of the copolymer components in this specification is a measured value obtained by converting it to standard polystyrene using a gel permeation chromatography analyzer.

[0026] The weight-average molecular weight (Mw) in this invention can be measured, for example, using the following measuring device and measurement conditions. Measurement device: Waters Corporation, product name "ACQUITY APC" Measurement conditions: Column ·ACQUITY APC XT45 1.7μm×1 piece ·ACQUITY APC XT125 2.5μm×1 piece ·ACQUITY APC XT450 2.5μm×1 piece Mobile phase: Tetrahydrofuran 0.8 mL / min Sample concentration: 0.2% by mass Detector: Differential refractive index (RI) detector Standard material: Polystyrene (Waters, Inc., Molecular weight: 266-1,800,000) Column temperature: 40℃ RI detector temperature: 40℃

[0027] 2. Ingredients (B): Tackifier components The adhesive composition of the present invention contains a tackifier component as component (B). This component can be any tackifier commonly used in the art, and is not particularly limited. Specifically, examples include rosin compounds, terpene compounds, petroleum resins, and the like.

[0028] The hot-melt adhesive of the present invention contains a tackifying resin B. The tackifying resin B is not particularly limited and includes rosin compounds, terpene compounds, petroleum resins, etc. Among these, terpene compounds and petroleum resins are preferred, and petroleum resins (especially hydrogenated petroleum resins) are particularly preferred.

[0029] There are no particular limitations on the content of component (B) in the adhesive composition of the present invention, and it may be set as appropriate. For example, it is preferably 40 to 65% by mass, and more preferably 50 to 60% by mass, of 100% by mass of the adhesive composition.

[0030] By increasing the content of component (B) in the adhesive composition of the present invention to 40% by mass or more, the tackiness of the adhesive composition is improved, and its adhesion to the adherend is enhanced. Furthermore, by reducing the content of component (B) to 65% by mass or less, the adhesive composition becomes softer and more easily exhibits holding power even at low temperatures.

[0031] Examples of the rosin compounds mentioned above include natural rosin, modified rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, and pentaerythritol ester of modified rosin.

[0032] Examples of the terpene compounds mentioned above include copolymers of natural terpenes, three-dimensional polymers of natural terpenes, hydrogenated derivatives of natural terpene copolymers, terpene resins, and hydrogenated derivatives of phenol-modified terpene resins.

[0033] Examples of the above petroleum resins include C5-based petroleum resins, C9-based petroleum resins, C5C9-based petroleum resins, and dicyclopentadiene-based petroleum resins. Hydrogenated petroleum resins (partially hydrogenated petroleum resins, fully hydrogenated petroleum resins), which are obtained by hydrogenating these petroleum resins, are also included. Among hydrogenated petroleum resins, partially hydrogenated petroleum resins are more preferable because they have higher compatibility with component (A) and superior heat stability. C5-based petroleum resins are petroleum resins made from the C5 fraction of petroleum, C9-based petroleum resins are petroleum resins made from the C9 fraction of petroleum, and C5C9-based petroleum resins are petroleum resins made from both the C5 and C9 fractions of petroleum. Examples of the C5 fraction include cyclopentadiene, isoprene, and pentane. Examples of the C9 fraction include styrene, vinyltoluene, and indene. As for C5-based petroleum resins and C5-C9-based petroleum resins, those containing dicyclopentadiene (DCPD), which is derived from cyclopentadiene, a type of C5 fraction, in their backbone are preferred.

[0034] As component (B), considering the odor and thermal stability of the resulting adhesive composition, it is preferable to use petroleum resin (including partially hydrogenated petroleum resin and fully hydrogenated petroleum resin), and more preferable to use partially hydrogenated petroleum resin and fully hydrogenated petroleum resin.

[0035] In particular, when using C5-C9 petroleum resin, considering the improvement of low-temperature adhesion and wettability, it is preferable that the resin be liquid at 23°C, and it is preferable that the adhesive composition of the present invention contains 5% by mass or more of C5-C9 petroleum resin per 100% by mass, and more preferably 8% by mass or more. Furthermore, in order to ensure sufficient adhesion, it is preferable that the adhesive composition of the present invention contains 15% by mass or less of C5-C9 petroleum resin per 100% by mass, and more preferably 10% by mass or less.

[0036] Component (B) can be used individually or as a mixture of the above.

[0037] There are no particular limitations on the softening point temperature of component (B). However, in order to prevent adhesive residue from forming in the adhesive composition of the present invention, it is preferable that the softening point temperature be 90°C or higher, and more preferably 100°C or higher. On the other hand, in order to ensure sufficient adhesion, it is preferable that the softening point temperature be 110°C or lower.

[0038] As the tackifier component of component (B), commercially available products can be used. Examples of commercially available products include ENEOS Material's "HA-085", "HA-103", "HB-103", and "HB-125", Arakawa Chemical's "Alcon-90" and "Alcon M-100", Idemitsu Kosan's "iMarb P100", Kolon's "Skolets SU400", and Yasuhara Chemical's "YS Resin TO-105".

[0039] 3. Ingredients (C): Plasticizer components The adhesive composition of the present invention contains a plasticizer component as component (C). A wide range of known plasticizers can be used as the plasticizer component, and there are no particular limitations. Among these, a liquid plasticizer is preferred. The term "liquid" above means that it has fluidity at 25°C (i.e., it changes shape to conform to the container when placed in it).

[0040] Examples of such plasticizers include polybutene, paraffinic process oil (hereinafter also simply referred to as "paraffinic oil"), naphthenic process oil, aromatic process oil, liquid paraffin, and hydrocarbon synthetic oil. Among these, the use of paraffinic process oil (paraffinic oil) is preferred.

[0041] Among paraffin oils, those with a kinematic viscosity of 70 mPa·s or higher at 40°C are preferred, and those with a kinematic viscosity of 80 mPa·s or higher are more preferred, in order to exhibit low-temperature adhesion. Furthermore, in order to ensure sufficient adhesion, the kinematic viscosity of the paraffin oil is preferably 100 mPa·s or lower, and more preferably 90 mPa·s or lower.

[0042] The plasticizer components can be used individually or in combination of several types from the above list.

[0043] Commercially available paraffin oil can be used. Examples of commercially available products include Idemitsu Kosan's "PW-32", "PS-90", and "PS-32".

[0044] Commercially available naphthenic process oils (naphthenic oils) can be used. Examples of commercially available products include PetroChina's "KN4010," Idemitsu Kosan's "Diana Fresia N28," "Diana Fresia N90," "Diana Fresia U46," and "Diana Process Oil NR."

[0045] Commercially available aromatic process oils can be used. An example of such a product is "Aromax" manufactured by Nippon Oil Corporation.

[0046] The number-average molecular weight of these process oils is not limited, but is preferably between 200 and 700, and more preferably between 300 and 600.

[0047] Commercially available liquid paraffin can be used. Examples of commercially available products include "P-100" from MORESCO and "Kaydol" from Sonneborn.

[0048] Commercially available hydrocarbon-based synthetic oils can be used. Examples of commercially available products include "Lucant HC-10" and "Lucant HC-20" manufactured by Mitsui Chemicals, Inc.

[0049] There are no particular limitations on the content of component (C) in the adhesive composition of the present invention, but it is preferably 10 to 20% by mass, and more preferably 12 to 17% by mass, of 100% by mass of the adhesive composition of the present invention. By setting the content of component (C) to 10% by mass or more, the cohesive strength of the adhesive composition of the present invention is improved, and adhesive residue is less likely to occur. By setting the content of component (C) to 20% by mass or less, the adhesive composition of the present invention becomes softer and exhibits better holding power even at low temperatures.

[0050] 4. Any additives The adhesive composition of the present invention may contain various additives as needed, provided that they do not impair the effects and objectives of the present invention. Examples of such additives include stabilizers and particulate fillers.

[0051] Stabilizers are used to improve the stability of adhesive compositions by mitigating issues such as molecular weight reduction, gelation, discoloration, and odor generation due to heat. The specific types of stabilizers are not limited to those mentioned above; examples include antioxidants and ultraviolet absorbers.

[0052] Antioxidants are used to prevent oxidative degradation of the adhesive composition. UV absorbers are used to improve the lightfastness of the adhesive composition. Antioxidants and UV absorbers are commonly used in disposable products, and since the adhesive composition of the present invention is generally applied as an adhesive for positioning disposable absorbent articles, as described later, they can be suitably used as additives.

[0053] Examples of antioxidants include 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,4-bis(octylthiomethyl)-o-cresol, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, and 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl Examples include phenolic antioxidants such as [L]phenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)] acrylate, and tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane; sulfur-based antioxidants such as dilauryl thiodipropionate, lauryl stearyl thiodipropionate, and pentaerythritol tetrakis(3-lauryl thiopropionate); phosphorus-based antioxidants such as tris(nonylphenyl) phosphite and tris(2,4-di-t-butylphenyl) phosphite; and lactone-based antioxidants. Examples of UV absorbers include benzotriazole-based UV absorbers such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-t-butylphenyl)benzotriazole, and 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole; benzophenone-based UV absorbers such as 2-hydroxy-4-methoxybenzophenone; salicylate-based UV absorbers; cyanoacrylate-based UV absorbers; and hindered amine-based light stabilizers. These can be used individually or in combination.

[0054] Commercially available stabilizers can be used. Examples include "Sumisorb SumiLizer GM" and "Sumisorb 200" from Sumitomo Chemical Co., Ltd., "Irganox 1010" from BASF, and "JF-79" from Johoku Chemical Co., Ltd. These commercially available stabilizers can be used alone or in combination.

[0055] The particulate fillers are not limited to those mentioned above, and examples include calcium carbonate, kaolin, talc, titanium dioxide, mica, and styrene beads. These particulate fillers can be used individually or in combination.

[0056] 5. Method for manufacturing adhesive compositions The adhesive composition of the present invention can be manufactured by the same method as conventionally known hot-melt adhesive compositions, and is not particularly limited. Specifically, one method involves adding the above-mentioned components simultaneously or sequentially and then melt-mixing them using a stirrer.

[0057] 6. Uses of adhesive compositions The adhesive composition of the present invention is useful as a hot-melt adhesive for positioning absorbent articles. In addition to having high initial strength, the decrease in adhesive holding power (adhesive strength and tackiness) is suppressed even when there is a long period between the production of the absorbent article and its use. Furthermore, even at low temperatures, the absorbent article does not shift from the position it is attached to the clothing during use, and there is no adhesive residue left on the clothing when it is peeled off after use.

[0058] Examples of absorbent items mentioned above include sanitary napkins, incontinence liners, postpartum panties, breast pads, underarm sweat pads, disposable diapers, pet sheets, hospital gowns, surgical gowns, etc., but are not limited to these. The term can be applied to all sanitary products that are primarily disposable and used to absorb bodily fluids.

[0059] The absorbent article is constructed by coating at least one material, such as woven fabric, nonwoven fabric, rubber, resin, paper, or polyolefin film, with the hot-melt adhesive of the present invention. Polyethylene film is preferred as the polyolefin film for reasons of durability and cost, and generally, breathable polyethylene film is used.

[0060] The adhesive composition of the present invention is particularly suitable for sanitary napkins among the absorbent articles mentioned above. Generally, sanitary napkins have an absorbent material between a breathable top sheet and a liquid-impermeable back sheet, with the top sheet in contact with the skin and the back sheet in contact with underwear. A positioning adhesive is provided on the back sheet (base material) to fix the sanitary napkin in the desired position on the underwear. The hot-melt adhesive of the present invention exhibits particularly excellent effects when the back sheet of the sanitary napkin is a polyolefin film.

[0061] The method of applying the adhesive composition to the substrate (the part to which the adhesive is applied) of an absorbent article, and the amount applied, can be appropriately selected according to the type of absorbent article and are not particularly limited. Coating methods are broadly classified into contact coating and non-contact coating. Contact coating refers to a coating method in which the sprayer is in contact with the substrate when applying the hot-melt adhesive. Non-contact coating refers to a coating method in which the sprayer is not in contact with the substrate when applying the hot-melt adhesive.

[0062] Examples of contact coating methods include slot coater coating and roll coater coating. Examples of non-contact coating methods include spiral coating which can coat in a spiral pattern, omega coating or control seam coating which can coat in a wave pattern, slot spray coating or curtain spray coating which can coat in a surface pattern, and dot coating which can coat in a dot pattern.

[0063] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these examples, and can be implemented in various forms without departing from the spirit of the invention. [Examples]

[0064] The embodiments of the present invention will be described in more detail below based on examples, but the present invention is not limited to these.

[0065] (Examples and Comparative Examples) The components shown in Tables 1 to 3 below were mixed and melt-kneaded using a stirrer at approximately 130°C for approximately 60 minutes to obtain the adhesive compositions of Examples 1 to 18 and Comparative Examples 1 to 6.

[0066] Details of ingredients A to C are shown below. (A1-1) Styrene-butadiene block copolymer CHIMEI Co., Ltd.'s "KIBITON PB-5502 (product name)" (styrene content 35% by mass, diblock ratio 70% by mass, Mw: triblock copolymer 111,000, diblock copolymer 52,000) (A1-2) Styrene-butadiene block copolymer Asahi Kasei Corporation's "Asaprene T-438 (product name)" (styrene content 35% by mass, diblock ratio 70% by mass, Mw: triblock copolymer 108,000, diblock copolymer 52,000) (A1-3) Styrene-butadiene block copolymer LCY's "GP-3545 (product name)" (styrene content 45% by mass, diblock ratio 65% by mass, Mw: triblock copolymer 91,000, diblock copolymer 47,000) (A2-1) Styrene-isoprene block copolymer Quintac 3520 (product name), manufactured by Nippon Zeon Co., Ltd. (Styrene content 15% by mass, diblock ratio 78% by mass, Mw: Triblock copolymer 338,000, Diblock copolymer 137,000) (A2-2) Styrene-isoprene block copolymer Quintac 3433 (product name), manufactured by Nippon Zeon Co., Ltd. (Styrene content 16% by mass, diblock ratio 66% by mass, Mw: triblock copolymer 238,000, diblock copolymer 97,000) (A3-1) Styrene-ethylene-butylene block copolymer Kraton's "G-1726 (product name)" (styrene content 30% by mass, diblock ratio 70% by mass, Mw: triblock copolymer 55,900, diblock copolymer 30,000) (A3-2) Styrene-ethylene-butylene block copolymer Asahi Kasei Corporation's "ToughTec P1500 (product name)" (styrene content 30% by mass, diblock ratio 70% by mass, Mw: triblock copolymer 102,000, diblock copolymer 50,500) (A3-3) Styrene-ethylene-butylene block copolymer Kraton's "MD1648 (product name)" (styrene content 20% by mass, Mw: triblock copolymer 55,000) (B1) Tackifying resin Hydrogenated petroleum resin "HB-103 (product name)" manufactured by Eneos Materials (ring and ball softening point 100℃) (B2) Tackifying resin Hydrogenated petroleum resin “HA-103 (product name)” manufactured by Eneos Materials (ring and ball softening point 100℃) (B3) Tackifying resin Hydrogenated petroleum resin "Arkon P-100 (product name)" manufactured by Arakawa Chemical Co., Ltd. (ring and ball softening point 100℃) (B4) Tackifying resin Hydrogenated petroleum resin “FUCLEAR FM-100 (product name)” manufactured by UPM (ring and ball softening point 100℃) (B5) Adhesive resin Hydrogenated petroleum resin "Arkon M-100 (product name)" manufactured by Arakawa Chemical Co., Ltd. (ring and ball softening point 100℃) (B6) Tackifying resin Syntomar hydrogenated petroleum resin "Regalite C6100L (product name)" (ring and ball softening point 100℃) (B7) Tackifying resin Idemitsu Kosan's hydrogenated petroleum resin "Imarv S-100 (product name)" (ring-type softening point 100℃) (B8) Tackifying resin Synthomar's hydrogenated petroleum liquid resin "Regalite C8010 (product name)" (C1) Plasticizer PetroChina naphthenic oil "KN-4010 (product name)" (kinematic viscosity at 40°C: 170 mPa·s) (C2) Plasticizer Idemitsu Kosan's paraffin oil "PS-90 (product name)" (kinematic viscosity at 40°C: 90 mPa·s) (C3) Plasticizer Idemitsu Kosan's paraffin oil "PS-32 (product name)" (kinematic viscosity at 40°C: 32 mPa·s)

[0067] [Table 1]

[0068] [Table 2]

[0069] [Table 3]

[0070] [Adhesive strength at low temperature and room temperature] Each hot melt adhesive is applied to the release paper to a thickness of 30 μm, and then a 30 μm thick polyethylene sheet is used. The material was laminated onto a film (substrate) and molded into a specimen measuring 70 mm in length and 30 mm in width to create a test piece.

[0071] Peel strength test A cotton cloth for dye fastness testing (Kanakin No. 3: simulated clothing) conforming to JIS L 0803 was cut to a width of 35 mm (adhesion area 35 mm x 10 mm), and the adhesive portion of the test piece was bonded to it by rolling a 2 kg roller back and forth once. The initial strength was obtained by measuring the peel strength immediately after bonding at a speed of 300 mm / min in a 23°C environment. In addition, a sample left at 50°C for 4 weeks was similarly measured, and the ratio (%) to the initial strength was calculated to obtain the strength over time.

[0072] The initial strength evaluation criteria were as follows, and any product with an initial strength of less than 3.5N was deemed unacceptable. ◎: 5N or higher ○: 4N or more and less than 5N △: 3.5N or more and less than 4N ×: Less than 3.5N

[0073] The criteria for evaluating strength over time were as follows: any test that did not achieve 70% of its initial strength after 4 weeks was deemed unacceptable. ◎: Maintain over 80% ○: Maintain between 75% and 80% △: Maintaining a percentage between 70% and 75% ×: Maintenance rate less than 70%

[0074] Low-temperature probe tack test The test was performed using a Nichiban probe tack tester under a 23°C environment. The test specimen was cut to 25 mm in length and 25 mm in width. A cylindrical SUS rod with a diameter of 5 mm was pressed against the sample with a 20 g load for a contact time of 1 second, and the strength was measured when the rod was lifted at a moving speed of 1 cm / second. A probe tack value of less than 80 was considered a failure. ◎: Probe tack value of 100 or higher ○: Probe tack value between 90 and 100 △: Probe tack value between 80 and 90 ×: Probe tack value less than 80

[0075] Adhesive residue evaluation test A test cotton cloth (Kanakin No. 3: simulated clothing) was cut to a width of 35 mm (adhesion area 35 mm x 10 mm). A JIS dye fastness test cotton cloth (Kanakin No. 3: simulated clothing) conforming to JIS L 0803 was placed on the adhesive portion of the test piece, and a 60 mm x 100 mm x 2 mm thick acrylic plate was placed over it. A load of 2.1 kg was applied on top of the plate for 2 hours, and then peeled off at a speed of 300 mm / min in a 23°C environment. The presence or absence of adhesive residue on the bonded surface of the test cotton cloth was visually checked, and if adhesive residue was found, the test was deemed unsuccessful.

[0076] As shown in Tables 1-3, when the adhesive compositions of each example were used, good results were obtained in each evaluation test. On the other hand, when the adhesive compositions of each comparative example were used, a failure result was obtained in at least one of the evaluation tests.

Claims

1. An adhesive composition comprising component (A): copolymer component, component (B): tackifier component, and component (C): plasticizer component, The aforementioned component (A) comprises component (A1): styrene-butadiene-styrene block copolymer (SBS), component (A2): styrene-isoprene-styrene block copolymer (SIS), and component (A3): hydrogenated styrene block copolymer. An adhesive composition wherein the content of component (A3) in 100% by mass of component (A) is 35% by mass or more.

2. The composition according to claim 1, wherein the content of component (A3) in 100% by mass of the total mass of component (A2) and component (A3) is 50% by mass or less.

3. The composition according to claim 1 or 2, wherein the component (C) is paraffin oil, and the paraffin oil has a kinematic viscosity of 90 mPa·s or more at 40°C.

4. The composition according to claim 1 or 2, wherein the total mass of components (A1), (A2), and (A3) is 25% by mass or more of 100% by mass of the entire composition.

5. The composition according to claim 1 or 2, wherein the softening point of component (B) is 90 to 110°C.

6. The composition contains 5 to 15% by mass of C5-C9 petroleum resin in 100% by mass of the entire composition. The composition according to claim 1 or 2, wherein the C5-C9 petroleum resin is liquid at 23°C.

7. The composition according to claim 1 or 2, for positioning absorbent articles.

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