Adhesive composition, method for producing same, and adhesive

Abstract

An adhesive composition containing a hydroxyl-terminated urethane prepolymer, a tackifying resin, and a polyisocyanate compound, the hydroxyl-terminated urethane prepolymer being a reaction product of an alkylene oxide polymer having a number average molecular weight of 3,000 or more and a diisocyanate compound.

Description

Technical Field

[0001] This invention relates to adhesive compositions and methods for manufacturing adhesives that can be applied to skin, as well as adhesives, adhesive materials, wearable devices, and wearable device kits. Background Technology

[0002] As an adhesive for skin-adhesive materials such as plasters, medical tapes, poultices, and plasters, and / or as an adhesive for skin-adhesive patch-type wearable devices that continuously obtain biological information such as body temperature and brain waves, urethane-based adhesives are used.

[0003] As a urethane-based adhesive for skin adhesion, for example, Patent Document 1 describes a medical adhesive composition containing urethane resin (A), a tackifying resin (B) with a softening point of 75°C or higher and having hydroxyl groups, and an isocyanate curing agent (C). The adhesive strength ratio [(X2) / (X1)] of the adhesive strength (X1) of the stainless steel sheet after 20 minutes at 23°C and 50%RH (Relative Humidity) to the adhesive strength (X2) after 24 hours at 23°C and 50%RH is 0.8 to 1.5.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-81438 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, the inventors conducted research and found that the adhesive composition described in Patent Document 1 does not maintain its adhesive state for a long time when wetted by water, i.e., its long-term water resistance is insufficient.

[0009] The present invention was made in view of the following circumstances, and its object is to provide adhesive compositions and methods for manufacturing the same, which provide adhesives with sufficient adhesion to devices and sealants and sufficient long-term water resistance, as well as adhesives, bonding materials, wearable devices and wearable device kits.

[0010] Solution for solving the problem

[0011] The inventors conducted in-depth research and found that the adhesive composition described in the examples of Patent Document 1 could not achieve sufficient long-term water resistance when the number average molecular weight of the polyol used as the raw material for the urethane resin was below 2,000. Furthermore, the inventors discovered that an adhesive composition containing a urethane resin synthesized using a polyol with a high number average molecular weight and a tackifying resin could provide sufficient adhesion to equipment and sealants, as well as sufficient long-term water resistance. This invention is based on these insights.

[0012] The present invention provides the following methods.

[0013] [1] An adhesive composition comprising a hydroxyl-terminated urethane prepolymer, a tackifying resin and a polyisocyanate compound, wherein the hydroxyl-terminated urethane prepolymer is a reaction product of an oxidized olefin polymer with a number average molecular weight of 3,000 or more and a diisocyanate compound.

[0014] [2] According to the adhesive composition described in [1] above, wherein the hydroxyl-terminated urethane prepolymer is a reaction product of an oxidized olefin polymer with a number average molecular weight of 3,000 or more and a diisocyanate compound in the presence of a tin-free catalyst.

[0015] [3] The adhesive composition according to [1] or [2] above, wherein the tackifying resin is a tackifying resin with a softening point of 70°C or higher.

[0016] [4] The adhesive composition according to any one of [1] to [3] above, wherein the tackifying resin is a terpene-based tackifying resin or a styrene-based tackifying resin.

[0017] [5] The adhesive composition according to any one of [1] to [4] above, wherein the content of ethylene oxide-based structural units in the hydroxyl-terminated urethane prepolymer is 8 to 55% by mass.

[0018] [6] The adhesive composition according to any one of [1] to [5] above, wherein the oxidized olefin polymer comprises an oxidized olefin polymer A having 2 or more hydroxyl groups per molecule and an oxidized olefin polymer B having 1 hydroxyl group per molecule.

[0019] [7] The adhesive composition according to any one of [1] to [6] above, wherein the weight average molecular weight of the hydroxyl-terminated urethane prepolymer is 50,000 or more.

[0020] [8] A method for manufacturing an adhesive composition, wherein an oxidized olefin polymer having a number-average molecular weight of 3,000 or more is reacted with a diisocyanate compound to obtain a hydroxyl-terminated urethane prepolymer.

[0021] The hydroxyl-terminated urethane prepolymer, the tackifying resin, and the polyisocyanate compound are mixed.

[0022] [9] The method for manufacturing the adhesive composition according to [8] above, wherein the hydroxyl-terminated urethane prepolymer is a reaction product obtained by reacting an olefinic polymer with a number average molecular weight of 3,000 or more with a diisocyanate compound in the presence of a tin-free catalyst.

[0023]

[10] In the method for manufacturing the adhesive composition according to [9] above, the tin-free catalyst is more than 0.001 parts by mass and less than 0.1 parts by mass relative to 100 parts by mass of the oxidized olefin polymer.

[0024]

[11] An adhesive, which is a cured product of the adhesive composition described in any one of [1] to [7] above.

[0025]

[12] An adhesive material having a substrate and an adhesive layer disposed on at least a portion of the surface of the substrate, the adhesive layer comprising the adhesive described in

[11] above.

[0026]

[13] The adhesive material described in

[12] above is an adhesive tape.

[0027]

[14] A wearable device having a wearable device body and an adhesive layer,

[0028] The adhesive layer is disposed on at least a portion of the skin-opposite side of the wearable device, and the adhesive layer comprises the adhesive described above

[11] .

[0029]

[15] A wearable device kit comprising a wearable device body and comprising at least one of the adhesive described in

[11] and the adhesive material described in

[12] or

[13] .

[0030] The effects of the invention

[0031] According to the present invention, it can provide adhesive compositions and methods for manufacturing adhesives that provide sufficient adhesion to devices and sealants and sufficient long-term water resistance, as well as adhesives, bonding materials, wearable devices and wearable device kits. Detailed Implementation

[0032] The definitions and meanings of the terms and expressions used in this specification are as follows.

[0033] Skin refers to human skin.

[0034] Number-average molecular weight (Mn) and weight-average molecular weight (Mw) are the converted molecular weights of polystyrene determined by gel permeation chromatography (GPC) based on a standard curve prepared using standard polystyrene samples.

[0035] The hydroxyl value was determined according to JIS K 1557-1:2007.

[0036] The degree of unsaturation was determined according to JIS K 1557-3:2007.

[0037] The isocyanate index refers to the equivalence ratio ([isocyanate group] / [active hydrogen group]) of the isocyanate group to the active hydrogen group (e.g., hydroxyl group) in the reaction, expressed as a percentage.

[0038] [Adhesive Composition]

[0039] The adhesive composition of the embodiments of the present invention (hereinafter referred to as the present embodiment) comprises a hydroxyl-terminated urethane prepolymer, a tackifying resin and a polyisocyanate compound, wherein the aforementioned hydroxyl-terminated urethane prepolymer is a reaction product of an oxidized olefin polymer with a number average molecular weight of 3,000 or more and a diisocyanate compound.

[0040] According to the adhesive composition of this embodiment, an adhesive with sufficient adhesion to equipment and sealant and sufficient long-term water resistance can be obtained.

[0041] (Hydroxy-terminated carbamate prepolymer)

[0042] The hydroxyl-terminated urethane prepolymer of this embodiment is a reaction product of an oxidized olefin polymer with a number-average molecular weight of 3,000 or higher and a diisocyanate compound. This allows for the production of an adhesive with sufficient adhesion to equipment and sealants, as well as adequate long-term water resistance.

[0043] In this embodiment, the hydroxyl-terminated urethane prepolymer is preferably the reaction product of an oxidized olefin polymer with a number-average molecular weight of 3,000 or higher and a diisocyanate compound in the presence of a tin-free catalyst. This allows for the production of a skin-friendly adhesive that is free of tin-containing catalysts that can cause adverse effects on the skin.

[0044] From the viewpoint of obtaining an adhesive with sufficient adhesion to equipment and sealants and sufficient long-term water resistance, the weight-average molecular weight of the hydroxyl-terminated urethane prepolymer is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 200,000 or more. From the viewpoint of obtaining an adhesive with sufficient adhesion to equipment and sealants and sufficient long-term water resistance, and from the viewpoint of ease of manufacture, this weight-average molecular weight is preferably 50,000 to 500,000, more preferably 100,000 to 500,000, even more preferably 200,000 to 450,000, even more preferably 200,000 to 400,000, and even more preferably 250,000 to 300,000.

[0045] From the viewpoint of obtaining an adhesive that has sufficient adhesion to equipment and sealant and sufficient long-term water resistance, the content of ethylene oxide-based structural units (hereinafter referred to as "EO units") in the hydroxyl-terminated urethane prepolymer is preferably 8 to 55% by mass, more preferably 8 to 40% by mass, even more preferably 8 to 20% by mass, even more preferably 8 to 18% by mass, even more preferably 8 to 16% by mass, and even more preferably 8 to 13% by mass.

[0046] When the EO unit content in hydroxy-terminated urethane prepolymers is low, skin irritation is low. Within the above range, it is easy to obtain adhesives that are skin-friendly, have sufficient adhesion to devices and sealants, and have sufficient long-term water resistance.

[0047] The EO units in hydroxyl-terminated urethane prepolymers originate from the EO units of the oxidized olefin chains that constitute the oxidized olefin polymers. 13 C-NMR (nuclear magnetic resonance) measurements were used to analyze the monomer composition of the oxidized olefin chain in the hydroxyl-terminated urethane prepolymer, thereby determining the content of EO units in the hydroxyl-terminated urethane prepolymer.

[0048] The total amount of structures derived from olefinic polymers with a number average molecular weight of 3,000 or more and structures derived from diisocyanate compounds in the hydroxyl-terminated urethane prepolymer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass.

[0049] <Oxylenene Polymers>

[0050] The number-average molecular weight of the olefin oxide polymer in this embodiment is 3,000 or higher. When using olefin oxide polymers with low molecular weights to obtain hydroxyl-terminated carbamate prepolymers, it is difficult to increase the molecular weight of the hydroxyl-terminated carbamate prepolymer, resulting in low water resistance. Since the olefin oxide polymer in this embodiment has a number-average molecular weight of 3,000 or higher, it is possible to obtain hydroxyl-terminated carbamate prepolymers with high molecular weights, thereby enabling the production of adhesives with sufficient adhesion to equipment and sealants and sufficient long-term water resistance.

[0051] Furthermore, the number average molecular weight of the oxidized olefin polymer in this embodiment is preferably 50,000 or less. If it is 50,000 or less, it is possible to prevent the molecular weight of the obtained hydroxyl-terminated urethane prepolymer from becoming too large and the viscosity of the adhesive composition from becoming too high, resulting in excellent processability of the adhesive composition.

[0052] Based on these views, the number average molecular weight of the oxidized olefin polymer is preferably 3,000 to 50,000, more preferably 5,500 to 45,000, further preferably 6,000 to 40,000, even more preferably 7,000 to 30,000, and even more preferably 8,000 to 25,000.

[0053] The oxidized olefin polymer can be one type of oxidized olefin polymer or two or more types of oxidized olefin polymers.

[0054] When multiple olefinic polymers are used in the synthesis of hydroxyl-terminated urethane prepolymers, the number-average molecular weight of the olefinic polymers refers to the value obtained by weighting the amount of the multiple olefinic polymers used in the synthesis of the hydroxyl-terminated urethane prepolymers.

[0055] When multiple olefin oxidase polymers are used in the synthesis of hydroxyl-terminated urethane prepolymers, the number average molecular weight of at least one of these polymers must be 3,000 or more, and the number average molecular weight of all of these polymers may be 3,000 or more. For example, when the olefin oxidase polymers used in the synthesis of hydroxyl-terminated urethane prepolymers are olefin oxidase polymer (1), olefin oxidase polymer (2), and olefin oxidase polymer (3), the number average molecular weight of at least one of these three polymers (e.g., olefin oxidase polymer (1)) must be 3,000 or more, the number average molecular weight of two of these three polymers (e.g., olefin oxidase polymers (1) and (2)) may be 3,000 or more, and the number average molecular weight of all of these three polymers (i.e., all of olefin oxidase polymers (1), (2), and (3)) may be 3,000 or more. The value obtained by weighted averaging of the number average molecular weights of all of these three types of olefin oxidase polymers (1), (2), and (3) based on the blending amount must be 3,000 or more.

[0056] The content of the variety of oxidized olefin polymers with a number average molecular weight of 3,000 or more in the total amount of 100% by mass of the various oxidized olefin polymers used in the synthesis of hydroxyl-terminated urethane prepolymers is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, for example, 100% by mass.

[0057] The average content of EO units in the olefin oxide polymer is preferably 8 to 55% by mass. If the average content of EO units in the olefin oxide polymer is within this range, it is easy to obtain an adhesive that is gentle on the skin and has good adhesion to circuits and the like. From this viewpoint, the average content of EO units in the olefin oxide polymer is more preferably 8 to 40% by mass, more preferably 8 to 20% by mass, even more preferably 8 to 18% by mass, even more preferably 8 to 16% by mass, and even more preferably 8 to 13% by mass.

[0058] The average EO unit content in olefin oxide polymers refers to the weighted average of the EO unit content in each olefin oxide polymer, based on the blending amounts of various olefin oxide polymers used in the synthesis of hydroxyl-terminated carbamate prepolymers. The EO unit content in each olefin oxide polymer is calculated based on the EO blending amounts of the raw materials used in the synthesis of the olefin oxide polymer. It should be noted that the EO unit content in olefin oxide polymers can also be calculated similarly to the EO unit content in hydroxyl-terminated carbamate prepolymers. 13 The result is obtained by C-NMR measurement.

[0059] When the average content of EO units in the oxidized olefin polymer is low, the skin irritation is low. Within the above range, it is easy to obtain an adhesive that is skin-friendly, has sufficient adhesion to devices and sealants, and has sufficient long-term water resistance.

[0060] For olefin oxide polymers, from the viewpoint of obtaining adhesives with sufficient adhesion to equipment and sealants and sufficient long-term water resistance, the average number of hydroxyl groups per molecule of the olefin oxide polymer is preferably 1.5 to 3.0, more preferably 1.7 to 2.8, and even more preferably 1.9 to 2.6. The average number of hydroxyl groups per molecule of the olefin oxide polymer refers to the value obtained by weighted averaging based on the blending amounts of various olefin oxide polymers used in the synthesis of hydroxyl-terminated urethane prepolymers.

[0061] The oxidized olefin polymer can be one type of oxidized olefin polymer or two or more types of oxidized olefin polymers.

[0062] The oxidized olefin polymer preferably comprises oxidized olefin polymer A (hereinafter also referred to as "polymer A") having 2 or more hydroxyl groups per molecule, and oxidized olefin polymer B (hereinafter also referred to as "polymer B") having 1 hydroxyl group per molecule.

[0063] Preferably, the hydroxyl groups of polymers A and B react with the isocyanate groups of the diisocyanate compound to form urethane bonds, and the unreacted hydroxyl groups are the terminal hydroxyl groups of the molecular chain of the hydroxyl-terminated urethane prepolymer.

[0064] The total content of polymer A and polymer B in the oxidized olefin polymer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass.

[0065] From the viewpoint of obtaining an adhesive that has sufficient adhesion to equipment and sealant and sufficient long-term water resistance, the content ratio of polymer A to polymer B in the oxidized olefin polymer is preferably 10 / 90 to 95 / 5 by mass, more preferably 30 / 70 to 90 / 10, further preferably 50 / 50 to 85 / 15, and even more preferably 60 / 40 to 85 / 15.

[0066] [Oxyolefin polymer A]

[0067] The number of hydroxyl groups per molecule of polymer A is 2 or more, preferably 2 to 6.

[0068] Polymer A can be one or more olefin oxide polymers. By forming polymer A from two or more olefin oxide polymers, it is easy to adjust the adhesive strength to achieve good adhesion.

[0069] When polymer A is formed from two or more olefinic polymers, the average number of hydroxyl groups per molecule of polymer A is preferably 2.1 to 3.0, more preferably 2.2 to 2.9, and even more preferably 2.3 to 2.8.

[0070] By making the average number of hydroxyl groups of polymer A within the above range, it is easy to obtain an adhesive that suppresses the burden on the skin where the device is fixed and does not easily leave adhesive residue on the skin.

[0071] The average number of hydroxyl groups per molecule of polymer A can be calculated from the hydroxyl value of polymer A and the measured value of Mn using the formula hydroxyl value × Mn / 56,100.

[0072] When polymer A is formed from two olefin oxide polymers, polymer A can include olefin oxide polymer A1 (hereinafter also simply referred to as "polymer A1"), which has 3 hydroxyl groups per molecule, and olefin oxide polymer A2 (hereinafter also simply referred to as "polymer A2"), which has 2 hydroxyl groups per molecule. Polymer A1 can be a single type or two or more types. Similarly, polymer A2 can be a single type or two or more types.

[0073] Polymer A may also contain olefinic polymers with 4 or more hydroxyl groups per molecule.

[0074] It should be noted that when polymer A is composed of polymer A1 and polymer A2, the weighted average of the number of hydroxyl groups per molecule of polymer A1 (3) and the number of hydroxyl groups per molecule of polymer A2 (2), based on the composition ratio (mixing amount) of polymer A1 and polymer A2, is regarded as the average number of hydroxyl groups of polymer A.

[0075] From the viewpoint of ease of adjusting the adhesive strength, the total amount of polymers A1 and A2 in a total of 100 parts by mass of polymer A is preferably 85 parts by mass or more, more preferably 90 parts by mass or more, and even more preferably 95 parts by mass or more.

[0076] Of the total 100 parts by mass of polymer A, it is particularly preferred that the total amount of polymer A1 and polymer A2 is 100 parts by mass, that is, polymer A is composed of polymer A1 and polymer A2.

[0077] From the viewpoint of obtaining an adhesive that has sufficient adhesion to equipment and sealant and sufficient long-term water resistance, polymer A1 is preferably 20 parts by mass or more, more preferably 25 to 95 parts by mass, and even more preferably 30 to 90 parts by mass in a total of 100 parts by mass of polymer A1 and polymer A2.

[0078] From the same point of view, polymer A2 is preferably 80 parts by mass or less, more preferably 5 to 75 parts by mass, and even more preferably 10 to 70 parts by mass in a total of 100 parts by mass of polymer A1 and polymer A2.

[0079] When polymer A is composed of, for example, polymer A1 and polymer A2, from the viewpoint of obtaining an adhesive that has sufficient adhesion to equipment and sealant and sufficient long-term water resistance, the content of polymer A1 is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, and even more preferably 30 to 50 parts by mass in a total of 100 parts by mass of polymer A1, polymer A2 and polymer B in the oxidized olefin polymer.

[0080] From the same point of view, the content of polymer A2 in the total of 100 parts by mass of polymer A1, polymer A2 and polymer B in the oxidized olefin polymer is preferably 15 to 50 parts by mass, more preferably 30 to 50 parts by mass, and even more preferably 30 to 40 parts by mass.

[0081] From the same point of view, the content of polymer B in the total of 100 parts by mass of polymers A1, A2 and B in the oxidized olefin polymer is preferably 5 to 40 parts by mass, more preferably 10 to 35 parts by mass, and even more preferably 10 to 20 parts by mass.

[0082] The average content of EO units in polymer A is preferably 0-80% by mass, more preferably 1-50% by mass, even more preferably 5-30% by mass, and even more preferably 8-25% by mass.

[0083] The average content of EO units in polymer A can be determined by... 13 The monomer composition of the oxidized olefin chain in polymer A is determined by C-NMR determination. For example, if the oxidized olefin chain in polymer A consists of EO and PO units, the EO unit content can be calculated based on the peak area of ​​the methylene group representing the EO unit and the peak area of ​​the methyl group representing the PO unit.

[0084] In the case where polymer A is composed of polymer A1 and polymer A2, the EO unit content of polymer A1 and polymer A2 is also the same.

[0085] It should be noted that the average content of EO units in polymer A can be considered as a value calculated from the blending amount of EO in the raw materials for polymer A. In the case where polymer A is composed of, for example, polymer A1 and polymer A2, the EO unit content of polymer A1 and polymer A2 is weighted and averaged based on the composition ratio (blending amount) of polymer A1 and polymer A2, and the resulting value is considered as the EO unit content of polymer A.

[0086] From the viewpoints of good adhesive strength, suppression of residual adhesive, and formation of an adhesive layer with good flexibility, the Mn of polymer A is preferably 1,000 to 50,000, more preferably 5,000 to 30,000, and even more preferably 8,000 to 25,000.

[0087] When the Mw / Mn (molecular weight distribution) of polymer A is close to 1 and the molecular weight distribution is narrow, the hydroxyl-terminated urethane prepolymer is less likely to become high-viscosity, which can achieve high efficiency in synthesis. Therefore, it is preferred to be 1.25 or less, more preferably 1.22 or less, and even more preferably 1.20 or less.

[0088] Furthermore, from the viewpoint of the good curability of hydroxyl-terminated urethane prepolymers and the suppression of adhesive residue, the closer the degree of unsaturation of polymer A is to 0 meq / g, the more preferred it is, preferably 0.020 meq / g or less, more preferably 0.018 meq / g or less, and even more preferably 0.015 meq / g or less.

[0089] When polymer A is formed from two or more olefin oxide polymers, each olefin oxide polymer is preferably within the range of Mn, Mw / Mn and degree of unsaturation described above.

[0090] The synthesis method of polymer A is not particularly limited. For example, it can be obtained by ring-opening addition polymerization of a compound having a cyclic ether structure, preferably an epoxide, with an initiator having two or more active hydrogens in the presence of a catalyst. When polymer A is composed of polymer A1 and polymer A2, it can also be obtained by combining an initiator having three active hydrogens and an initiator having two active hydrogens to perform ring-opening addition polymerization of a compound having a cyclic ether structure, thereby simultaneously generating polymer A1 and polymer A2. From the viewpoint of more accurately adjusting the mixing amounts of polymer A1 and polymer A2, it is preferable to synthesize and mix polymer A, obtained by ring-opening addition polymerization of a compound having a cyclic ether structure with an initiator having three active hydrogens, and polymer B, obtained by ring-opening addition polymerization of a compound having a cyclic ether structure with an initiator having two active hydrogens, separately.

[0091] Compounds having a cyclic ether structure are preferably straight-chain or branched with 2 to 14 carbon atoms, more preferably with 2 to 10 carbon atoms, and even more preferably with 2 to 4 carbon atoms. Compounds having a cyclic ether structure can be a single type or two or more types.

[0092] Examples of compounds having a cyclic ether structure include ethylene oxide (EO), propylene oxide (PO), 1,2-epoxybutane, 2,3-epoxybutane, methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, lauryl glycidyl ether, hexyl glycidyl ether, and tetrahydrofuran. EO and PO are preferred.

[0093] When two or more compounds with cyclic ether structures are used in combination, the arrangement of the oxidized alkenyl groups derived from each compound in polymer A can be random or block.

[0094] Groups with active hydrogen initiators include, for example, hydroxyl, carboxyl, and amino groups having hydrogen atoms bonded to nitrogen atoms. Among these, hydroxyl groups are preferred, and alcoholic hydroxyl groups are more preferred.

[0095] Examples of initiators with three hydroxyl groups include glycerol, trimethylolethane, trimethylolpropane, and 1,2,6-hexanetriol. One of these can be used alone, or two or more can be used in combination.

[0096] Examples of initiators having two hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol. One of these can be used alone, or two or more can be used in combination.

[0097] The number of active hydrogens in the initiator is typically equivalent to the number of hydroxyl groups per molecule of the oxidized olefin polymer. Polymer A1 can be synthesized, for example, using glycerol as an initiator. Conversely, polymer A2 can be synthesized, for example, using propylene glycol as an initiator.

[0098] It should be noted that the initiator for the synthesis of olefin oxide polymers can be... 13 C-NMR determination was used to determine the species and quantity. In the case where polymer A is composed of polymer A1 and polymer A2, the species and quantity were determined based on the C-NMR spectra of polymer A. 13 The information on the type and amount of initiators determined by C-NMR was used to determine the content ratio of oxidized alkenyl groups such as EO units and PO units bonded to each initiator, and to determine the ratio of polymer A1 to polymer A2.

[0099] Ring-opening addition polymerization can be carried out using known catalysts such as alkaline catalysts like potassium hydroxide, transition metal compound-porphyrin complex catalysts such as complexes obtained by reacting organoaluminum compounds with porphyrins, complex metal cyanide complex catalysts, and catalysts containing phosphazene compounds. Among these catalysts, complex metal cyanide (DMC) catalysts are preferred from the viewpoint of easily obtaining olefin oxide polymers with narrow molecular weight distribution and relatively low viscosity. As complex metal cyanide complexes, known compounds can be used, such as zinc hexacyanocobaltate complexes with tert-butanol as a ligand.

[0100] The synthesis of oxidized olefin polymers based on ring-opening addition polymerization using DMC catalysts can be carried out by known methods, such as those described in International Publication No. 2003 / 062301, International Publication No. 2004 / 067633, Japanese Patent Application Publication No. 2004-269776, Japanese Patent Application Publication No. 2005-15786, International Publication No. 2013 / 065802, and Japanese Patent Application Publication No. 2015-10162.

[0101] [Oxyolefin polymer B]

[0102] Each molecule of olefin oxidase polymer B has one hydroxyl group. Polymer B can be one type of olefin oxidase polymer or two or more types of olefin oxidase polymers.

[0103] The number of hydroxyl groups in polymer B can be determined in the same way as in polymer A. 13 The type and amount of initiator in the synthetic raw materials are determined by C-NMR determination to confirm the presence of the precursor.

[0104] From the viewpoints of forming an adhesive layer with good flexibility, good adhesive strength of the adhesive, and suppressing residual adhesive, the Mn of polymer B is preferably 4,000 to 30,000, more preferably 4,500 to 25,000, and even more preferably 5,000 to 20,000.

[0105] When the Mw / Mn ratio of polymer B is close to 1 and the molecular weight distribution is narrow, the hydroxyl-terminated urethane prepolymer is less likely to become high-viscosity, which can achieve high efficiency in synthesis. Therefore, it is preferred to be less than 1.20, more preferably less than 1.13, and even more preferably less than 1.10.

[0106] Furthermore, from the viewpoint of the good curability of hydroxyl-terminated urethane prepolymers and the suppression of adhesive residue in the adhesive layer, the degree of unsaturation of polymer B is preferably 0.015 meq / g or less, more preferably 0.013 meq / g or less, and even more preferably 0.010 meq / g or less, and the closer to 0 meq / g, the more preferred.

[0107] The synthesis method of polymer B is not particularly limited. For example, it can be obtained by ring-opening addition polymerization of a compound having a cyclic ether structure, preferably an epoxide, with an initiator having an active hydrogen in the presence of a catalyst.

[0108] Compounds with cyclic ether structures are described in the same way as polymer A. PO is preferred alone, or in combination with EO and PO.

[0109] From the viewpoint of achieving a good balance between adhesion to the skin and adhesion to the device and obtaining an adhesive with suppressed crystallinity, the average content of EO units in polymer B is preferably 0 to 80% by mass, more preferably 0 to 60% by mass, and even more preferably 0 to 50% by mass.

[0110] The average content of EO units in polymer B is calculated in the same way as in polymer A.

[0111] The groups containing active hydrogen in the initiator can be the same groups as those in polymer A, preferably hydroxyl groups, and more preferably alcoholic hydroxyl groups.

[0112] From the viewpoint of ease of acquisition, a monohydric alcohol having 2 to 4 carbon atoms is preferred as an initiator, such as n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, and tert-butanol, with n-butanol, sec-butanol, isobutanol, and tert-butanol being the most preferred. One initiator may be used alone, or two or more may be used in combination.

[0113] Ring-opening addition polymerization can be carried out using the same known methods as in the case of polymer A.

[0114] <Diisocyanate compounds>

[0115] The diisocyanate compound used to synthesize hydroxyl-terminated urethane prepolymers is an organic compound having two isocyanate groups in one molecule. The diisocyanate compound can be any of aliphatic, alicyclic, or aromatic diisocyanate compounds. A single diisocyanate compound can be used, or two or more can be used in combination.

[0116] As an aliphatic diisocyanate compound, it can be either linear or branched, such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethyl diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate.

[0117] Examples of alicyclic diisocyanate compounds include isophorone diisocyanate (IPDI), hydrogenated diphenylmethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (HMDI), 1,4-cyclohexane diisocyanate, methylcyclohexene diisocyanate, and 1,3-bis(isocyanate methyl)cyclohexane.

[0118] Examples of diisocyanate compounds possessing aromatic ring structures include toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, phenyldimethylmethylene diisocyanate, and tetramethylphenyldimethylmethylene diisocyanate (TMXDI).

[0119] From the viewpoint of the good curability of hydroxyl-terminated urethane prepolymers and the acquisition of adhesive layers with good flexibility, HDI, IPDI, HMDI, and TMXDI are preferred, and HDI is more preferred.

[0120] Alternatively, as a diisocyanate compound, a difunctional isocyanate-terminated urethane prepolymer obtained by reacting the diisocyanate compound described above with a diol (e.g., ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, etc.) can also be used.

[0121] Tin-free catalysts

[0122] The tin-free catalyst is a tin-free urethane esterification catalyst. In this embodiment, a tin-free catalyst is preferred as the urethane esterification catalyst.

[0123] From the viewpoint of obtaining a low-irritant, skin-friendly adhesive, the adhesive of this embodiment is preferably free of tin and tin compounds.

[0124] Examples of tin-free catalysts include tertiary amine catalysts and organometallic catalysts containing metals other than tin. A single catalyst can be used, or two or more can be used in combination. From the viewpoint of better reaction promotion, tin-free catalysts are preferably organometallic catalysts.

[0125] Examples of metals included in organometallic catalysts that contain metals other than tin include zinc, bismuth, titanium, lead, iron, cobalt, and zirconium. Among these, zinc and bismuth are preferred from the viewpoints of low skin irritation and ease of handling, with zinc being more preferred.

[0126] Examples of tertiary amine catalysts include triethylamine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).

[0127] Organometallic catalysts containing metals other than tin include those containing zinc, bismuth, titanium, lead, iron, cobalt, and zirconium, with those containing bismuth or zinc being preferred. Examples of organometallic catalysts containing zinc, bismuth, titanium, lead, iron, cobalt, and zirconium include zinc compounds such as zinc naphthenate, zinc carboxylate such as zinc 2-ethylhexanoate, and zinc acetylacetonate; bismuth compounds such as bismuth 2-ethylhexanoate and bismuth neodecanoate; titanium compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate, with bismuth neodecanoate or zinc carboxylate being preferred.

[0128] From the viewpoint of good reaction promotion and reduction of residual metal components, the amount of tin-free catalyst used in the reaction of olefin polymer with diisocyanate compound is preferably more than 0.001 parts by mass and less than 0.1 parts by mass relative to 100 parts by mass of olefin polymer, more preferably more than 0.005 parts by mass and less than 0.05 parts by mass, and even more preferably 0.01 to 0.04 parts by mass.

[0129] (Tackifying resin)

[0130] The tackifying resin in this embodiment is not particularly limited, and may include one or both of tackifying resins with a softening point of 70°C or higher and tackifying resins with a softening point of lower than 70°C. It is preferable to include a tackifying resin with a softening point of 70°C or higher, and even more preferably, a tackifying resin with a softening point of 70°C or higher. By including a tackifying resin with a softening point of 70°C or higher, it is easy to obtain an adhesive with sufficient adhesive strength and that inhibits residue on the skin when peeled off.

[0131] Examples of tackifying resins include rosin-based tackifying resins, terpene-based tackifying resins, alicyclic saturated hydrocarbon-based tackifying resins, styrene-based tackifying resins, and acrylic tackifying resins. From the viewpoint of improving adhesion to skin and SUS steel sheets, terpene-based or styrene-based tackifying resins are preferred. From the viewpoint of good adhesion to phenolic resins, terpene-based tackifying resins are more preferred. Furthermore, from the viewpoint of less coloring of the adhesive, styrene-based tackifying resins are more preferred.

[0132] In the adhesive composition of this embodiment, either a tackifying resin having hydroxyl groups or a tackifying resin not having hydroxyl groups may be appropriately contained. From the viewpoint of moderately suppressing adhesion to the skin and further improving water resistance, a tackifying resin not having hydroxyl groups may be appropriately used. The adhesive composition of this embodiment may not contain a tackifying resin not having hydroxyl groups.

[0133] Specific examples of rosin-based tackifying resins include unmodified rosins (raw rosin), such as resin rosin, wood rosin, and tall oil rosin; modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins, etc., obtained by modifying these unmodified rosins through hydrogenation, disproportionation, polymerization, etc.); and various other rosin derivatives; etc. Examples of the aforementioned rosin derivatives include rosin esters, such as substances obtained by esterifying unmodified rosin with alcohols (i.e., rosin esters) and substances obtained by esterifying modified rosin with alcohols (i.e., modified rosin esters); unsaturated fatty acid-modified rosin obtained by modifying unmodified rosin or modified rosin with unsaturated fatty acids; unsaturated fatty acid-modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; rosin alcohols obtained by reducing the carboxyl groups in unmodified rosin, modified rosin, unsaturated fatty acid-modified rosin, or unsaturated fatty acid-modified rosin esters; metal salts of rosin (especially rosin esters), such as unmodified rosin, modified rosin, and various rosin derivatives; rosin phenolic resins obtained by adding phenol to rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and then thermally polymerizing them; and preferably, rosin ester-based tackifying resins.

[0134] Rosin-based tackifying resins can be commercially available products. Examples include: Harima Chemicals Group, Inc.'s "HARIESTER TF", "HARIESTER S", "NEOTALL G2", "NEOTALL 101N", "NEOTALL 125HK", "HARITACK 8LJA", "HARITACK ER95", "HARITACK SE10", "HARITACK PH", "HARITACK F85", "HARITACK F105", "HARITACK FK100", "HARITACK FK125", and "HARITACK PCJ"; Eastman Chemical Company's "Foral 105-E", "Foral 85-E", and "Foral AX-E"; and Arakawa Chemical Industry Co., Ltd.'s "SUPER ESTER A-75", "SUPER ESTER A-100", "SUPER ESTER A-115", "SUPER ESTER A-125", "PENSEL A", "PENSEL AZ", "PENSEL C", and "PENSEL 2000". GUANGDONG "KF382S", "KF392S", "KF364", "KF384S", "KF394S", "KF398S", "KF399S", "KF452S" made by KOMO Corporation ", "KF462S", "KF454S", "KF464S", "KP120", "KP130", "KP140", "KP150", "K107", "K108", etc.

[0135] Examples of terpene-based tackifying resins include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers; modified terpene resins obtained by modifying these terpene resins (phenol modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.); etc. Examples of the above-mentioned modified terpene resins include terpene-modified phenolic resins, aromatic-modified terpene resins (e.g., styrene-modified terpene resins), and hydrogenated terpene resins. Among these, aromatic-modified terpene resins are preferred. One or more of the above-mentioned terpene-based tackifying resins (e.g., aromatic-modified terpene resins) with different types and properties (e.g., softening points) can be used in combination.

[0136] Terpene-based tackifying resins can be commercially available products. Examples include YS RESIN TO125 (manufactured by YASUHARA CHEMICAL CO., LTD.), YS Polyster TH130 (manufactured by YASUHARA CHEMICAL CO., LTD.), and ARKON M115 (manufactured by Arakawa Chemical Industry Co., Ltd.).

[0137] Examples of hydrocarbon-based tackifying resins include aliphatic (C5 series) petroleum resins, aromatic (C9 series) petroleum resins, aliphatic / aromatic copolymers (C5 / C9 series) petroleum resins, their hydrides (e.g., alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins (alicyclic saturated hydrocarbon resins)), various modified versions of these resins (e.g., maleic anhydride modified versions), coumarone resins, coumarone-indene resins, and other hydrocarbon-based resins, with alicyclic saturated hydrocarbon resins being preferred. Hydrocarbon-based tackifying resins can be used alone or in combination of two or more.

[0138] Examples of styrene-based tackifying resins include styrene homopolymers, α-methylstyrene homopolymers, α-methylstyrene / styrene copolymers, styrene / aliphatic copolymers, α-methylstyrene / styrene / aliphatic copolymers, C9 series petroleum resins, C5 / C9 series petroleum resins, phenol-modified styrene resins, and their hydrogenates. Styrene-based tackifying resins can be used alone or in combination of two or more.

[0139] Preferably, styrene homopolymers, α-methylstyrene homopolymers, α-methylstyrene / styrene copolymers, styrene / aliphatic copolymers, α-methylstyrene / styrene / aliphatic copolymers, phenol-modified styrene resins, and their partially hydrogenated derivatives are preferred; more preferably, styrene homopolymers, α-methylstyrene homopolymers, α-methylstyrene / styrene copolymers, and their partially hydrogenated derivatives are preferred. These exhibit excellent compatibility with (meth)acrylic acid block copolymers. Styrene homopolymers are particularly preferred.

[0140] Styrene-based tackifying resins can be used in commercially available products. Examples include Arizona Chemical Co.'s "SYLVARES SA-85", "SYLVARES SA-100", "SYLVARES SA-120", "SYLVARES SA-140", and "SYLVARES 520"; Exxon Mobil Corporation's "Escorez ECR-213" and "Escorez ECR-807"; YASUHARA CHEMICAL CO., LTD.'s "YS RESIN SX100"; Mitsui Chemicals' "FTR0100", "FTR2120", "FTR2140", "FTR6100", "FTR6110", "FTR6125", "FTR7100", "FTR8100", "FTR8120", and "FMR0150"; and Eastman Chemical Company's "Kristalex F85", "Kristalex F100", "Kristalex F115", "Kristalex 1120", and "Kristalex F120". 3070", "Kristalex 3085", "Kristalex 3100", "Kristalex 5140", etc.

[0141] Examples of acrylic tackifying resins include acrylic tackifying resins based on acrylic polymers (homogeneities or copolymers) that use one or more alkyl methacrylates as monomer components. Specific examples of alkyl methacrylates include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecanyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, octadecyl methacrylate, nonadecanyl methacrylate, eicosyl methacrylate, and other C1-20 alkyl methacrylates. Alkyl methacrylates having straight-chain or branched alkyl groups with 4 to 18 carbon atoms are preferred.

[0142] The aforementioned acrylic polymers may, as needed, contain units corresponding to other monomer components capable of copolymerizing with the aforementioned (meth)acrylate alkyl esters.

[0143] There is no particular limitation on the amount of tackifying resin used relative to 100 parts by weight of hydroxyl-terminated urethane prepolymer. From the viewpoint of obtaining an adhesive with sufficient adhesion to equipment and sealant and sufficient long-term water resistance, 0.5 to 150 parts by weight is preferred, more preferably 1.0 to 100 parts by weight, further preferably 3.0 to 50 parts by weight, and even more preferably 5.0 to 40 parts by weight.

[0144] (Polyisocyanate compounds)

[0145] Polyisocyanate compounds are curing agents for hydroxyl-terminated urethane prepolymers.

[0146] Polyisocyanate compounds are compounds having two or more isocyanate groups in one molecule. They can be used alone or in combination of two or more.

[0147] From the viewpoints of ease of acquisition and reactivity, diisocyanate compounds are preferred as polyisocyanate compounds. Furthermore, from the viewpoints of good adhesive strength and suppression of residue, polyisocyanate compounds having three or more isocyanate groups per molecule are preferred.

[0148] As a specific example of a diisocyanate compound, the same diisocyanate compound as the specific example of the diisocyanate compound constituting the above-mentioned hydroxyl-terminated urethane prepolymer can be listed.

[0149] Examples of polyisocyanate compounds having three or more isocyanate groups in one molecule include isocyanurate modified forms, biuret modified forms, urethane modified forms, which are derivatives of the above-mentioned diisocyanate compounds, and isocyanate-terminated urethane prepolymers (adducts) with three or more functions as reaction products of diisocyanate compounds and polyols (e.g., trimethylolpropane) having three or more hydroxyl groups in one molecule.

[0150] There is no particular limitation on the amount of polyisocyanate compound used relative to 100 parts by weight of the hydroxyl-terminated urethane prepolymer and the tackifying resin. From the viewpoint of obtaining an adhesive with sufficient adhesion to equipment and sealant and sufficient long-term water resistance, 0.5 to 100 parts by weight is preferred, more preferably 1.0 to 50 parts by weight, further preferably 1.0 to 30 parts by weight, and even more preferably 1.0 to 10 parts by weight.

[0151] (Other ingredients)

[0152] In addition to hydroxyl-terminated urethane prepolymers, tackifying resins, and polyisocyanate compounds, the adhesive composition may also contain other components. Examples of such other components include plasticizers, antioxidants, antistatic agents, fillers, UV absorbers, light stabilizers, conductivity enhancers, leveling agents, polyols, and various other additives. Solvents may also be included. Other components may be used alone or in combination of two or more, and may be mixed in amounts that do not impair the effects of the invention.

[0153] From the viewpoint of fully utilizing the effects of the present invention, the total content of the hydroxyl-terminated urethane prepolymer, tackifying resin and polyisocyanate compound in the adhesive composition (excluding solvent) is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and also preferably 100% by mass.

[0154] Plasticizers can be selected based on factors such as compatibility with other components and the wettability of the adhesive layer on the adhered objects. Examples include fatty acid esters and phosphate esters with 8 to 30 carbon atoms.

[0155] Antioxidants help to inhibit thermal degradation of the adhesive layer, and examples include phenolic, amine, sulfur-based, and phosphorus-based antioxidants. From the viewpoint of low skin irritation, phenolic antioxidants are preferred.

[0156] Antistatic agents help suppress damage to circuit patterns caused by electrostatic discharge, and examples include inorganic salts; ionic liquids containing imidazolium ions, pyridinium ions, ammonium ions, etc.; and surfactants.

[0157] Examples of fillers include talc, calcium carbonate, and titanium dioxide.

[0158] Examples of UV absorbers include benzophenone-based, benzotriazole-based, salicylic acid-based, oxaloyl aniline-based, cyanoacrylate-based, and triazine-based UV absorbers.

[0159] Examples of light stabilizers include hindered amine light stabilizers and ultraviolet stabilizers.

[0160] As conductive agents, examples include metallic microparticles such as silver nanoparticles.

[0161] As leveling agents, examples include polymeric leveling agents such as acrylic, vinyl, silicone, and fluorine-based agents.

[0162] In the adhesive composition of this embodiment, polyols may be further contained as other components, or they may not be contained. From the viewpoint of improving the adhesive strength, the number average molecular weight of the polyol is preferably 5,000 or less, more preferably 600 to 3,000.

[0163] However, according to the adhesive composition of this embodiment, even without polyols with a number average molecular weight of 5,000 or less, an adhesive with sufficient adhesive strength can be easily obtained. From the viewpoint of suppressing skin damage caused by excessive adhesive strength, the content of polyols with a number average molecular weight of 5,000 or less in the adhesive composition is preferably less than 2.5 parts by weight, more preferably 0 to 2.0 parts by weight, and even more preferably 0 to 1.0 parts by weight, relative to 100 parts by weight of the hydroxyl-terminated urethane prepolymer.

[0164] Similarly, relative to 100 parts by weight of the hydroxyl-terminated urethane prepolymer, the content of polyols other than the hydroxyl-terminated urethane prepolymer in the adhesive composition is preferably less than 2.5 parts by weight, more preferably 0 to 2.0 parts by weight, and even more preferably 0 to 1.0 parts by weight.

[0165] [Method for manufacturing adhesive composition]

[0166] The method for manufacturing the adhesive composition of this embodiment is as follows: reacting an oxidized olefin polymer with a number average molecular weight of 3,000 or more with a diisocyanate compound to obtain a hydroxyl-terminated urethane prepolymer, and mixing the aforementioned hydroxyl-terminated urethane prepolymer, tackifying resin and polyisocyanate compound.

[0167] By reacting the hydroxyl-terminated prepolymer thus obtained with a polyisocyanate compound, the adhesive composition of this embodiment described above can be suitably obtained.

[0168] It should be noted that when mixing the hydroxyl-terminated urethane prepolymer, tackifying resin and polyisocyanate compound, other components that may be included in the above adhesive composition may also be mixed in.

[0169] The hydroxyl-terminated urethane prepolymer is preferably obtained by reacting an olefin polymer with a number-average molecular weight of 3,000 or more with a diisocyanate compound in the presence of a tin-free catalyst. The olefin polymer with a number-average molecular weight of 3,000 or more, the diisocyanate compound, and the tin-free catalyst are the same as described above.

[0170] Hydroxyl-terminated urethane prepolymers can be manufactured, for example, by methods such as: adding an oxidized olefin polymer, a diisocyanate compound, a tackifying resin, a catalyst, and a solvent together into a reaction vessel; and by adding the diisocyanate compound dropwise or similarly into a reaction vessel in which the oxidized olefin polymer, tackifying resin, catalyst, and solvent have been added.

[0171] Examples of solvents include ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; and aromatic hydrocarbons such as toluene and xylene. A single solvent can be used, or two or more can be used in combination.

[0172] When using a solvent, from the viewpoint of uniformity of the reaction system and synthesis efficiency, the amount of solvent used is preferably 50 to 500 parts by mass relative to 100 parts by mass of the total olefin polymer, more preferably 70 to 400 parts by mass, and even more preferably 80 to 300 parts by mass.

[0173] Furthermore, from the viewpoint of efficiently obtaining hydroxyl-terminated urethane prepolymers with moderate molecular chain lengths, it is preferable to react the oxidized olefin polymer with the diisocyanate compound at an isocyanate index of less than 100, preferably 30 to 95, and more preferably 50 to 95.

[0174] From the viewpoint of promoting the urethane esterification reaction and inhibiting side reactions, the reaction temperature is preferably below 100°C, more preferably 70~95°C, and even more preferably 75~90°C.

[0175] After the reaction is complete, reaction terminators such as acetylacetone can be added to deactivate the catalyst.

[0176] From the viewpoint of obtaining an adhesive that has a good balance between adhesion to the skin and adhesion to the device, the average number of hydroxyl-terminated urethane prepolymer molecules is preferably less than 3.0, more preferably 1.7 to 2.9, and even more preferably 1.8 to 2.5.

[0177] The isocyanate index of the polyisocyanate compound reacting with the hydroxyl-terminated urethane prepolymer is preferably greater than 100, more preferably 101 to 1,500, and even more preferably 105 to 1,000.

[0178] [Adhesive]

[0179] The adhesive in this embodiment is a cured product of the adhesive composition described above.

[0180] An adhesive can be obtained by reacting and curing a hydroxyl-terminated urethane prepolymer in an adhesive composition with a polyisocyanate compound.

[0181] As described below, for example, an adhesive can form an adhesive layer by applying an adhesive composition to a substrate and allowing it to cure.

[0182] In the reaction of the hydroxyl-terminated urethane prepolymer with the polyisocyanate compound, a catalyst and solvent may be used as needed. As the solvent, the solvents described in the foregoing description of the [method for manufacturing the adhesive composition] may be used appropriately; these solvents may be the same or different, but are preferably the same.

[0183] When using a catalyst, a urethane esterification catalyst, which is a tin-free catalyst as described above, can be used. It can be the same as or different from the catalyst used in the synthesis of the hydroxyl-terminated urethane prepolymer. If the catalyst used in the synthesis of the hydroxyl-terminated urethane prepolymer remains, the residual catalyst can also play a catalytic role in the reaction of the hydroxyl-terminated urethane prepolymer with the polyisocyanate compound.

[0184] When a catalyst is added during the reaction of the hydroxyl-terminated urethane prepolymer with the polyisocyanate compound, the amount of catalyst added is preferably more than 0.001 parts by mass and less than 0.1 parts by mass relative to 100 parts by mass of the total hydroxyl-terminated urethane prepolymer and polyisocyanate compound, preferably 0.005 to 0.05 parts by mass, and more preferably 0.01 to 0.04 parts by mass. When a catalyst is added, after the reaction is complete, a reaction terminator is preferably added to deactivate the catalyst.

[0185] As solvents used in the reaction of hydroxyl-terminated carbamate prepolymers with polyisocyanate compounds, examples include solvents similar to those used in the synthesis of the hydroxyl-terminated carbamate prepolymers described above. These solvents may be the same as those used in the synthesis of the hydroxyl-terminated carbamate prepolymers or different solvents. If any solvent used in the synthesis of the hydroxyl-terminated carbamate prepolymers remains, it may be used undisturbed.

[0186] When using a solvent, the amount used is preferably 50 to 500 parts by mass, more preferably 70 to 400 parts by mass, and even more preferably 80 to 300 parts by mass relative to 100 parts by mass of the total hydroxyl-terminated urethane prepolymer and polyisocyanate compound.

[0187] From the viewpoint of promoting the urethane esterification reaction and suppressing side reactions, the reaction temperature of the hydroxyl-terminated urethane prepolymer with the polyisocyanate compound is preferably below 120°C, more preferably 40~110°C, and even more preferably 50~100°C.

[0188] [Paste Material]

[0189] The adhesive material of this embodiment has a substrate and an adhesive layer disposed on at least a portion of the surface of the substrate, the adhesive layer comprising the adhesive of this embodiment.

[0190] For adhesive materials having an adhesive layer formed using the adhesive composition of this embodiment, sufficient adhesion to the device and sealant can be obtained, and adhesive with sufficient long-term water resistance can be obtained.

[0191] As an adhesive material, it can be a sheet of the desired size corresponding to the usage method, or it can be cut to the desired size for use.

[0192] From a convenience standpoint, adhesive tape is the preferred adhesive material.

[0193] The adhesive composition for forming the adhesive layer can be a one-component type, depending on the way the adhesive material is used, etc., which premixes a hydroxyl-terminated urethane prepolymer and a polyisocyanate compound as a curing agent. Alternatively, it can be a two-component type consisting of a first agent containing a hydroxyl-terminated urethane prepolymer and a second agent containing a polyisocyanate compound as a curing agent.

[0194] From the viewpoint of ensuring good adhesion to the skin, the thickness of the adhesive layer is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 20 to 50 μm.

[0195] The substrate is preferably made of a material that conforms well to the shape of the skin or device and is not easily broken during the use of the adhesive material. Examples of substrates include those made of resin film, cloth, and paper. A single substrate can be used, or two or more substrates can be used in combination. Alternatively, a composite material based on lamination or similar methods can be used.

[0196] Materials used for resin films include, for example, polyurethane, polyamide, acrylic resins, polyethylene, polypropylene, polyolefins such as ethylene-vinyl acetate copolymer, and polyesters, with polyester films being preferred.

[0197] As a type of fabric, examples include woven fabric, non-woven fabric, braided fabric, and netting. Materials include resins used in the aforementioned resin films, as well as natural fibers such as cotton, silk, and wool.

[0198] The thickness of the substrate is not particularly limited as long as it can ensure conformability to the shape of the skin or device and prevent the substrate from breaking easily when the adhesive material is used. It is preferably 10 to 500 μm, and more preferably 20 to 400 μm.

[0199] To protect the surface of the adhesive layer before use of the adhesive material, the surface of the adhesive layer is preferably covered with a release liner. The release liner is properly peeled off from the surface of the adhesive layer when using the adhesive material.

[0200] Release liner can be any type of release liner used in known skin adhesive tapes, etc. Examples of release liner options include high-quality paper, cellophane, parchment paper coated with release agents such as silicone resin or fluororesin, and high-quality paper laminated with resin anchoring coating and polyethylene coated with release agents such as silicone resin or fluororesin. Alternatively, transparent resin films, such as polyester films, can also be used as release liner options.

[0201] The thickness of the release liner is not particularly limited as long as it can protect the adhesive layer and is easy to peel off during use; for example, it can be 15 to 200 μm.

[0202] The adhesive layer can be provided in one or more locations on a portion of the substrate surface of the resin film, either on a portion of a single side or on the entire single side. Alternatively, it can be provided on both sides of the substrate surface.

[0203] When the adhesive layer is bonded to the sealing material of the device, for example, from the viewpoint of properly securing the device, the adhesion strength to the phenolic resin, which is a common material used as a sealing material, is preferably 2.5 N / 15 mm or more, more preferably 3.0 N / 15 mm or more.

[0204] Similarly, from the viewpoint of properly securing the equipment, after the adhesive layer is adhered to the phenolic resin and then immersed in a container of tap water at 23°C for 7 days, the adhesion strength to the phenolic resin is preferably 1.0 N / 15 mm or more, more preferably 2.5 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more.

[0205] When the adhesive layer is bonded to the sealing material of the equipment, for example, from the viewpoint of properly fixing the equipment, the adhesion force to the SUS steel plate, which is a common material of the equipment, is preferably 2.0 N / 15 mm or more, more preferably 2.5 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more.

[0206] It should be noted that the adhesive force mentioned here is a value determined by the method based on JIS Z 0237:2009, specifically by the method described in the examples.

[0207] The adhesive material can be manufactured using known methods, such as applying an adhesive composition to a release liner, allowing it to cure to form an adhesive layer, and then bonding it to a substrate. Alternatively, methods can be described as applying an adhesive composition to a substrate, allowing it to cure to form an adhesive layer, and then bonding the release liner.

[0208] There are no particular limitations on the coating method of the adhesive composition. For example, known methods such as rod coating, knife coating, roller coating, scraper coating, die coating, microgravure coating, comma coating, slot coating, lip coating, and cast coating can be used.

[0209] After coating, in order to allow the solvent contained in the adhesive composition to fully evaporate, hot air drying at 40~80°C is preferred to cure it, thereby forming an adhesive layer.

[0210] Wearable devices

[0211] The wearable device of this embodiment has a wearable device body and an adhesive layer, wherein the adhesive layer is disposed on at least a portion of the surface of the wearable device opposite to the skin, and the adhesive layer contains the adhesive of this embodiment.

[0212] When the adhesive composition of this embodiment is used, a good balance is achieved between the adhesive force to the skin and the adhesive force to the device, and a skin-friendly adhesive layer is formed. Therefore, the adhesive of this embodiment is suitable for application to wearable devices that are adhered to the skin.

[0213] The adhesive layer can be formed, for example, in the manner described above for bonding materials.

[0214] Alternatively, the adhesive layer can be formed by clamping both sides with a release liner, without a substrate, and the wearable device body is bonded to the skin only through the adhesive layer.

[0215] Wearable devices that are attached to the skin include, for example, biosensors and environmental sensors. Detection targets for biosensors include, for example, cardiac electrical activity, pulse wave, body temperature, acceleration, heart rate interval, pulse interval, respiratory interval, electrocardiogram (ECG), electromyography (EMG), activity level, blood pressure, and electroencephalogram (EEG).

[0216] [Wearable Device Kit]

[0217] The wearable device kit of this embodiment includes a wearable device body and includes at least one of the adhesive and the adhesive material of this embodiment.

[0218] In this way, the main body of the wearable device may not have a pre-existing adhesive layer, but may be constructed in the following way: it has an adhesive or adhesive material as other components, which can form an adhesive layer when in use.

[0219] Adhesives and bonding materials can be used alone or in combination.

[0220] Example

[0221] The present invention will now be described in detail based on embodiments, but the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0222] [Determination Method]

[0223] The methods for determining the various physical properties in the following synthetic examples are described below.

[0224] <Number-average molecular weight (Mn) and weight-average molecular weight (Mw)>

[0225] Mn and Mw were determined by gel permeation chromatography (GPC) under the following conditions (polystyrene conversion), and the molecular weight distribution (Mw / Mn) was calculated from these values.

[0226] [Measurement Conditions]

[0227] • Equipment used: “HLC-8320GPC”, manufactured by Tosoh Corporation

[0228] • Columns used: "TSKgel (registered trademark) SuperMultiporeHZ-M", manufactured by Tosoh Corporation

[0229] • Detector: Differential Refractive Index (RI) Detector

[0230] • Detection temperature: 40℃

[0231] • Eluent: Tetrahydrofuran

[0232] • Flow rate: 0.350 mL / min

[0233] • Sample concentration: 0.5% by mass

[0234] • Sample injection volume: 10 μL

[0235] Standard sample: polystyrene

[0236] <Ethylene oxide (EO) unit content>

[0237] The EO unit content of each olefin oxide polymer is based on the amount of propylene oxide (PO) and EO used in the synthesis, and the amount of EO used is regarded as the EO unit content in the olefin oxide polymer.

[0238] The EO unit content of the hydroxyl-terminated urethane prepolymer is set as the weighted average of the EO unit content in each component of the raw material.

[0239] <Hydroxy value>

[0240] The hydroxyl value was determined according to Method B (automatic potentiometric titration) of JIS K 1557-1:2007.

[0241] <Unsaturation>

[0242] The degree of unsaturation was determined according to JIS K 1557-3:2007.

[0243] <Average number of hydroxyl groups per molecule of oxidized olefin polymer A>

[0244] The average number of hydroxyl groups per molecule of olefin polymers A1 and A2 used as olefin polymer A (the number of hydroxyl groups per molecule of the initiator used in the synthesis of each olefin polymer) is obtained by weighting the average number of hydroxyl groups per molecule of olefin polymer A based on the mixing amount of each olefin polymer.

[0245] <Average number of hydroxyl groups per molecule of hydroxyl-terminated carbamate prepolymer>

[0246] The average number of hydroxyl groups per molecule of each oxidized olefin polymer and each diisocyanate compound used in the synthesis of hydroxyl-terminated urethane prepolymers is considered as the weighted average of the number of hydroxyl groups per molecule based on the blending amounts of each oxidized olefin polymer and each diisocyanate compound.

[0247] [Substances Used]

[0248] The following shows the details of the synthesis examples and the substances used in them.

[0249] (1) Initiator

[0250] • TBA-DMC catalyst: Zinc hexacyanocobaltate complex with tert-butanol as ligand

[0251] (2) Adsorbent

[0252] • Adsorbent: Synthetic magnesium silicate; "KYOWAAD (registered trademark) 600S", manufactured by Kyowa Chemical Industry Co., Ltd.

[0253] (3) Polyisocyanate compounds

[0254] • 50M-HDI: Hexamethylene diisocyanate (HDI); "DURANATE (registered trademark) 50M-HDI", manufactured by Asahi Kasei Corporation

[0255] • D201: HDI-based difunctional isocyanate-terminated prepolymer; "DURANATE (registered trademark) D201", manufactured by Asahi Kasei Corporation

[0256] (4) Carbamate catalyst

[0257] • Bismuth neodecanoate; bismuth (Bi)-containing carbamate catalyst; manufactured by Sigma-Aldrich

[0258] XK627: Zinc carboxylate; zinc (Zn)-containing carbamate catalyst; "K-KAT XK627", manufactured by KINGINDUSTRIES.

[0259] (5) Curing agent

[0260] • Curing agent (polyisocyanate compound): HDI-based polyisocyanate; "DURANATE (registered trademark) E402-80B", manufactured by Asahi Kasei Corporation; solid content 80% by mass

[0261] (6) Tackifying resin

[0262] • Styrene resin: "YS RESIN (registered trademark) SX100", manufactured by YASUHARA CHEMICAL CO., LTD., softening point 100℃

[0263] • Terpene phenolic resin: "YS Polyster (registered trademark) TH130", manufactured by YASUHARA CHEMICAL CO.,LTD., softening point 130℃

[0264] • α-Methylstyrene resin: “SYLVARES SA140”, manufactured by Kraton Polymers Japan Limited, softening point 137℃

[0265] Phenol-modified α-methylstyrene resin: "SYLVARES 520", manufactured by Kraton Polymers Japan Limited, softening point 75℃.

[0266] (7) Oxidized olefin polymers

[0267] • A1: The oxidized olefin polymer synthesized in Example 1-1

[0268] • A2: Oxide polymers synthesized in Examples 1-2

[0269] • B1: Oxide polymers synthesized in Examples 1-3

[0270] • A3: Oxide polymers synthesized in Examples 1-4

[0271] ·A'1: "EXCENOL903", manufactured by AGC Co., Ltd.

[0272] ·A'2: "EXCENOL2026T", manufactured by AGC Co., Ltd.

[0273] ·B'1: "PREMINOL1002", manufactured by AGC Co., Ltd.

[0274] Synthesis of Oxide-Based Polymers

[0275] (Synthesis Example 1-1)

[0276] 1000g of glycerol as an initiator and TBA-DMC catalyst (metal concentration 46 ppm by mass) were added into a pressure-resistant container. After the container was purged with nitrogen, the reaction solution was stirred and heated to 135°C. 120g of propylene oxide (PO) was added to induce the reaction.

[0277] After the temperature of the reaction solution stopped rising, it was cooled to 135°C. While stirring the reaction solution, 3782.4g of PO and 945.6g of ethylene oxide (EO) were added to the container. After confirming that the internal pressure change had disappeared, an adsorbent was added to neutralize and remove the catalyst, yielding olefin oxide polymer A1.

[0278] (Synthesis Example 1-2)

[0279] In Synthesis Example 1-1, the initiator was changed from glycerol to propylene glycol, and the oxidized olefin polymer A2 was synthesized in the same manner as in Synthesis Example 1-1.

[0280] (Synthesis Example 1-3)

[0281] In Synthesis Example 1-1, the initiator was changed from glycerol to n-butanol, and 2364g of PO was added instead of EO after the reaction solution was cooled. Otherwise, the oxidized olefin polymer B1 was synthesized in the same manner as in Synthesis Example 1-1.

[0282] (Synthesis Example 1-4)

[0283] In Synthesis Example 1-1, the initiator was changed from glycerol to propylene glycol, and no EO was added after the reaction solution was cooled. Otherwise, the oxidized olefin polymer A3 was synthesized in the same manner as in Synthesis Example 1-1.

[0284] Table 1 shows the various physical properties of the oxidized olefin polymers A1~A3 and B1 synthesized as described above, as well as the commercially available oxidized olefin polymers A'1, A'2 and B'1.

[0285] [Table 1]

[0286]

[0287] Synthesis of hydroxyl-terminated carbamate prepolymers

[0288] (Synthesis example 2-1)

[0289] 45 parts by mass of oxidized olefin polymer A1, 35 parts by mass of oxidized olefin polymer A3, 20 parts by mass of oxidized olefin polymer B1, 50.6 parts by mass of toluene and 50.6 parts by mass of ethyl acetate were added to a reaction vessel equipped with a thermometer, stirrer and cooling pipe. 0.038 parts by mass of K-KAT XK-627 were added. After mixing at 40°C, 1.7 parts by mass of HDI (isocyanate index 85) were added, and the mixture was allowed to react at 80°C.

[0290] While appropriately diluting with ethyl acetate, the reaction was maintained at 80°C for 7 hours to obtain a 50% by mass transparent hydroxyl-terminated urethane prepolymer solution (urethane prepolymer U1; average hydroxyl number 2.2, EO unit content 9% by mass).

[0291] (Synthesis example 2-2)

[0292] As shown in Table 2, the diisocyanate compound HDI was changed to D-201 (isocyanate index 85), and its addition amount was changed. Otherwise, a 50% by mass solution of hydroxyl-terminated urethane prepolymer (also known as "urethane prepolymer U2") was prepared in the same manner as in Synthesis Example 2-1.

[0293] (Synthesis example 2-3)

[0294] As shown in Table 2, the catalyst K-KAT XK-627 was replaced with bismuth neodecanoate, and its addition amount was also changed. Otherwise, a 50% by mass solution of hydroxyl-terminated urethane prepolymer (also known as "urethane prepolymer U3") was prepared in the same manner as in Synthesis Example 2-1.

[0295] (Synthesis example 2-4)

[0296] As shown in Table 2, the catalyst K-KAT XK-627 was replaced with bismuth neodecanoate, and its addition amount was also changed. Otherwise, a 50% by mass solution of hydroxyl-terminated urethane prepolymer (also known as "urethane prepolymer U4") was prepared in the same manner as in Synthesis Example 2-2.

[0297] (Synthesis example 2-5)

[0298] The types and amounts of oxidized olefin polymers were changed as shown in Table 2. Otherwise, a 50% by mass solution of hydroxyl-terminated urethane prepolymer (also known as "urethane prepolymer U5") was prepared in the same manner as in Synthesis Example 2-1.

[0299] (Synthesis example 2-6)

[0300] The types and amounts of oxidized olefin polymers were changed as shown in Table 2. Otherwise, a 50% by mass solution of hydroxyl-terminated urethane prepolymer (also known as "urethane prepolymer U6") was prepared in the same manner as in Synthesis Example 2-1.

[0301] Table 2 shows the formulations of the olefin oxidant polymers, diisocyanate compounds, and catalysts used in Synthetic Examples 2-1 to 2-6.

[0302] [Table 2]

[0303]

[0304] [Making of Adhesive Materials]

[0305] (Example 1)

[0306] A 50% by weight solution of 180 parts by weight of hydroxyl-terminated urethane prepolymer U1 (equivalent to 90 parts by weight of hydroxyl-terminated urethane prepolymer U1), 10 parts by weight of tackifying resin YS RESIN SX100, and 5 parts by weight of curing agent were mixed to obtain an adhesive composition. After degassing, the adhesive composition was applied to a polyester film (38 μm thick) serving as a release liner using a doctor blade coater and dried at 100°C for 2 minutes to form an adhesive layer (25 μm thick). A polyester film (75 μm thick) serving as a substrate was then laminated onto this adhesive layer and cured in a hot air dryer at 40°C for 3 days to produce an adhesive material.

[0307] (Examples 2~14)

[0308] The formula is changed to that shown in Table 3, except that the adhesive material is prepared in the same way as in Example 1.

[0309] (Example 15)

[0310] In Example 1, the substrate was changed from polyester film (75 μm thick) to nonwoven fabric (200 μm thick), but the adhesive material was prepared in the same manner as in Example 1.

[0311] (Examples 16~28)

[0312] In Examples 2-14, the substrate was changed from polyester film (75 μm thick) to nonwoven fabric (200 μm thick), but the adhesive material was prepared in the same manner as in Examples 2-14.

[0313] [Evaluation of the adhesive material]

[0314] The adhesive materials manufactured in Examples 1 to 28 above were evaluated as follows. The evaluation results for Examples 1 to 14 are shown in Table 3. Examples 1 to 10 are exemplary cases, and Examples 11 to 14 are comparative examples.

[0315] For the substrate, Examples 15-28, which changed from polyester film (75 μm thick) to nonwoven fabric (200 μm thick), also obtained the same evaluation results as Examples 1-14. Examples 15-24 are exemplary examples, and Examples 25-28 are comparative examples.

[0316] <Adhesion>

[0317] (For phenolic resin (let stand for 20 minutes))

[0318] The adhesive layer of the adhesive material (100mm long, 15mm wide) with the release liner removed is overlapped with the phenolic resin board ("SUMILITE (registered trademark) PL-1102", manufactured by Sumitomo Bakelite Co., Ltd.; 125mm long, 30mm wide, 2mm thick). The adhesive layer is pressed against the phenolic resin board by using a rubber roller with a load of 2kg and a speed of 300mm / min, moving back and forth once from the substrate side of the adhesive material.

[0319] After standing for 20 minutes, the adhesive material is peeled off at a peel angle of 90° and a speed of 300 mm / min. The adhesive strength is then determined according to the method of JIS Z 0237:2009 when the substrate is phenolic resin (to phenolic resin).

[0320] Table 3 shows the average of the three measurements. Additionally, the measured adhesive strength was evaluated according to the following evaluation criteria.

[0321] [Evaluation Criteria (for phenolic resins)]

[0322] A: 3.0N / 15mm or more

[0323] B: 2.5N / 15mm or more and less than 3.0N / 15mm

[0324] C: 2.0N / 15mm or more but less than 2.5N / 15mm

[0325] D: Less than 2.0N / 15mm

[0326] In evaluation case A, it can be said that the adhesive strength of phenolic resin, a representative material such as sealing material for circuit patterns in wearable devices, is sufficient. On the other hand, in evaluation cases B to D, the adhesive strength of phenolic resin is insufficient.

[0327] (For phenolic resin (100% at 23℃ for 7 days))

[0328] Perform the same procedure as described above for "phenolic resin (let stand for 20 minutes)" to press the adhesive layer onto the phenolic resin board.

[0329] The phenolic resin board with the adhesive layer pressed on is immersed in a container filled with tap water at 23°C.

[0330] Seven days later, the phenolic resin board was removed from the container, and after gently wiping off the moisture, the adhesive layer was peeled off within 30 minutes at a peel angle of 90° and a speed of 300 mm / min to determine the adhesion strength.

[0331] Table 3 shows the average of the three measurements. Additionally, the measured adhesive strength was evaluated according to the following evaluation criteria.

[0332] In this test, adhesives rated B or higher exhibited excellent long-term water resistance and posed no practical problems. Adhesives rated A showed exceptionally excellent long-term water resistance.

[0333] [Evaluation Criteria (Phenolic Resin Board at 23℃, 100% Curing, 7 Days Later)]

[0334] A: 2.0N / 15mm or higher

[0335] B: 1.0N / 15mm or more and less than 2.0N / 15mm

[0336] C: Less than 1.0 N / 15 mm

[0337] (Regarding SUS)

[0338] The adhesive layer side of each adhesive material (100mm long, 25mm wide) after the release liner has been removed is overlapped with the SUS steel plate (made by Standard Testpiece; 125mm long, 30mm wide, 2mm thick). The adhesive layer is pressed against the SUS steel plate by using a rubber roller with a load of 2kg and a speed of 600mm / min, moving back and forth once from the substrate side of the adhesive material.

[0339] After standing for 20 minutes, the adhesive material is peeled off at a peel angle of 90° and a speed of 300 mm / min, and the adhesive strength is then measured according to the method of JIS Z 0237:2009.

[0340] Table 3 shows the average of the three measurements. Additionally, the measured adhesive strength was evaluated according to the following evaluation criteria.

[0341] [Evaluation Criteria (SUS)]

[0342] A: 3.0N / 15mm or more

[0343] B: 2.5N / 15mm or more and less than 3.0N / 15mm

[0344] C: Less than 2.5N / 15mm

[0345] If we are evaluating A and B, we can say that the SUS steel sheet has good adhesion to the JIS Z 0237:2009 standard.

[0346] (For the skin)

[0347] In the case of the adherend being the skin of the forearm of a person (3 subjects), the adhesive strength was measured in the same manner as in the case of the adherend being phenolic resin.

[0348] Table 3 shows the average values ​​of the measured values. Additionally, the measured adhesive strength was evaluated according to the following evaluation criteria.

[0349] [Evaluation Criteria (for Skin)]

[0350] A: 1.0N / 15mm or higher and 3.0N / 15mm or lower

[0351] B: More than 3.0N / 15mm and less than 5.0N / 15mm

[0352] C: Less than 1.0 N / 15 mm

[0353] D: Exceeds 5.0N / 15mm

[0354] In evaluation A, the adhesion to the skin can be considered moderate. In evaluation B, while the adhesion is sufficient, it is slightly too strong, and peeling requires more resistance compared to evaluation A. In evaluation C, the adhesion is too weak, making peeling easy. In evaluation D, the adhesion is too strong, making peeling difficult. Evaluations A and B indicate practically suitable adhesion.

[0355] <Skin Observation>

[0356] In an atmosphere of 23°C and 50%RH, a test piece (20 mm long and 15 mm wide) of the adhesive material was adhered to the skin of the forearm of three subjects. After one hour, the test piece was peeled off the skin, and the condition of the skin was visually observed.

[0357] The observation results should be evaluated according to the following evaluation criteria.

[0358] In this test, adhesives rated B or higher were safe for skin adhesion and could be used without practical problems. Adhesives rated A were particularly safe for skin adhesion.

[0359] [Evaluation Criteria]

[0360] A: There is no change compared to before the test piece was pasted.

[0361] B: Those with reddened skin.

[0362] C: Some individuals observed residual adhesive (adhesive residue).

[0363] [Table 3]

[0364]

[0365] The adhesives in Examples 1-10 combine low adhesion to the skin with high adhesion to the substrate, exhibit good long-term water resistance, and ensure the safety of skin adhesion.

[0366] In contrast, the adhesives in Examples 11 and 12 do not contain tackifying resins, making them difficult to bond to the SUS interface and resulting in poor adhesion to the SUS steel sheet. The adhesives in Examples 13 and 14 use hydroxyl-terminated urethane prepolymer U6 obtained from an oxidized olefin polymer with a low number-average molecular weight. Therefore, regardless of the presence or absence of tackifying resins, their long-term water resistance is not excellent, and their cohesive strength to the SUS steel sheet is insufficient, resulting in inadequate adhesion.

Claims

1. An adhesive composition comprising a hydroxyl-terminated urethane prepolymer, a tackifying resin, and a polyisocyanate compound, the hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer having a number average molecular weight of 3,000 or more and a diisocyanate compound.

2. The adhesive composition of claim 1, wherein, the hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer having a number average molecular weight of 3,000 or more and a diisocyanate compound in the presence of a tin-free catalyst.

3. The adhesive composition according to claim 1 or 2, wherein, the tackifying resin is a tackifying resin having a softening point of 70°C or more.

4. The adhesive composition according to claim 1 or 2, wherein, the tackifying resin is a terpene-based tackifying resin or a styrene-based tackifying resin.

5. The adhesive composition according to claim 1 or 2, wherein, the content of ethylene oxide-based structural units in the hydroxyl-terminated urethane prepolymer is 8 to 55 mass%.

6. The adhesive composition according to claim 1 or 2, wherein, the oxyalkylene polymer comprises an oxyalkylene polymer A having 2 or more hydroxyl groups per 1 molecule and an oxyalkylene polymer B having 1 hydroxyl group per 1 molecule.

7. The adhesive composition according to claim 1 or 2, wherein, the weight average molecular weight of the hydroxyl-terminated urethane prepolymer is 50,000 or more.

8. A method for producing an adhesive composition, wherein, an oxyalkylene polymer having a number average molecular weight of 3,000 or more and a diisocyanate compound are reacted to obtain a hydroxyl-terminated urethane prepolymer, the hydroxyl-terminated urethane prepolymer, the tackifying resin, and the polyisocyanate compound are mixed.

9. The method of producing an adhesive composition according to claim 8, wherein the hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer having a number average molecular weight of 3,000 or more and a diisocyanate compound in the presence of a tin-free catalyst.

10. The method of producing an adhesive composition according to claim 9, wherein The tin-free catalyst is more than 0.001 parts by mass and 0.1 parts by mass or less with respect to 100 parts by mass of the oxyalkylene polymer.

11. An adhesive that is a cured product of the adhesive composition described in claim 1.

12. A sticking material having a substrate and an adhesive layer provided to at least a portion of a surface of the substrate, the adhesive layer comprising the adhesive described in claim 11.

13. The sticking material described in claim 12, which is an adhesive tape.

14. A wearable device having a wearable device main body and an adhesive layer, the adhesive layer is provided to at least a portion of an opposite surface of the wearable device to a skin, and the adhesive layer comprises the adhesive described in claim 11.

15. A wearable device kit comprising a wearable device main body and comprising at least any one of the adhesive described in claim 11 and the sticking material described in claim 13.

Images