Urethane prepolymers, adhesives, adhesive materials, adhesive tapes, wearable devices, and wearable device kits.

Abstract

To provide a urethane prepolymer capable of obtaining an adhesive having excellent moisture permeability and achieving both low adhesion to the skin and high adhesion to a substrate, an adhesive, a patch, an adhesive tape, a wearable device and a wearable device kit.SOLUTION: There are provided a hydroxyl group terminal urethane prepolymer obtained by reacting an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3, an oxyalkylene polymer B having a number of hydroxyl groups per molecule of 1 and a diisocyanate compound, wherein the oxyalkylene polymer A has a number average molecular weight of 1000 to 50000, the oxyalkylene polymer B has a number average molecular weight of 5000 or more, the ethylene oxide unit content in the hydroxyl group terminal urethane prepolymer is more than 10 mass%, an adhesive, a patch, an adhesive tape, a wearable device and a wearable device kit.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to urethane prepolymers, adhesives, adhesive materials, adhesive tapes, wearable devices, and wearable device kits. [Background technology]

[0002] Adhesives applied to the skin are required to have excellent moisture permeability so that moisture from perspiration from the skin can evaporate to the outside of the adhesive material when used as the adhesive layer of the adhesive material.

[0003] Patent Document 1 describes a material with a moisture permeability of 5000 g / m². 2 The following is a polyurethane adhesive for skin application for days or longer, obtained by reacting (1) a polyol containing a polyoxyalkylene structure with a number average molecular weight of 5,000 or more and an average number of functional groups of 2 or more, (2) a polyol containing a polyoxyalkylene structure with a number average molecular weight of 1,500 to 5,000 and an average number of functional groups of 1, and (3) an organic polyisocyanate. The average number of functional groups of the total polyol used to obtain the above adhesive is 2 to 2.6, and the content of ethylene oxide units of the total polyol in the above adhesive is 3 to 8% by weight.

[0004] Furthermore, in recent years, adhesives have begun to be used to attach wearable devices to the skin. While high adhesion to the wearable device itself is required, low adhesion to the skin is also required to prevent skin damage when removing the wearable device from the skin. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 5457446 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The adhesive applied to the skin is required to have excellent moisture permeability and to achieve both low adhesiveness to the skin and high adhesiveness to the base material. However, the adhesive described in Patent Document 1 has a high adhesive force to both the skin and the base material. When the adhesive is applied to the skin, there is a risk of damaging the skin when peeling off the adhesive from the skin.

[0007] Therefore, an object of the present invention is to provide a urethane prepolymer, an adhesive, an adherent, an adhesive tape, a wearable device, and a wearable device kit that can obtain an adhesive having excellent moisture permeability and achieving both low adhesion to the skin and high adhesion to the base material.

Means for Solving the Problems

[0008] The above problems are solved by the following configurations. [1] A hydroxyl-terminated urethane prepolymer obtained by reacting an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3, an oxyalkylene polymer B having one hydroxyl group per molecule, and a diisocyanate compound, wherein the number average molecular weight of the oxyalkylene polymer B is 5000 or more, and the ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer is more than 10% by mass. [2] The hydroxyl-terminated urethane prepolymer according to [2], wherein the number average molecular weight of the oxyalkylene polymer B is more than 5000. [[!ID=3]] [3] The hydroxyl-terminated urethane prepolymer according to [1] or [2], wherein the oxyalkylene polymer A includes an oxyalkylene polymer a having three hydroxyl groups per molecule and an oxyalkylene polymer b having two hydroxyl groups per molecule. [4] The hydroxyl-terminated urethane prepolymer according to [3], wherein the ethylene oxide unit content of the oxyalkylene polymer a is 15% by mass or more. [5] The hydroxyl-terminated urethane prepolymer according to any one of [1] to [4], having an average number of hydroxyl groups of less than 3.0. [6] The hydroxyl-terminated urethane prepolymer according to any one of [1] to [5], wherein the ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer is 12 to 50% by mass. [7] An adhesive obtained by reacting a hydroxyl-terminated urethane prepolymer described in any of [1] to [6] with a curing agent containing a polyisocyanate compound having three or more isocyanate groups in one molecule, An adhesive having an ethylene oxide unit content of 10% by mass or more. [8] An adhesive obtained by reacting an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3, an oxyalkylene polymer B having a hydroxyl group per molecule of 1, and a polyisocyanate compound, The number-average molecular weight of the oxyalkylene polymer B is 5000 or more. An adhesive having an ethylene oxide unit content of 10% by mass or more. [9] The adhesive according to [8], wherein the number average molecular weight of the oxyalkylene polymer B is greater than 5000.

[10] The adhesive according to [8] or [9], wherein the oxyalkylene polymer A comprises an oxyalkylene polymer a having 3 hydroxyl groups per molecule and an oxyalkylene polymer b having 2 hydroxyl groups per molecule.

[11] The adhesive according to

[10] , wherein the ethylene oxide unit content of the oxyalkylene polymer a is 15% by mass or more.

[12] The adhesive according to any one of [8] to

[11] , wherein the ethylene oxide unit content in the adhesive is 12 to 50% by mass.

[13] The storage modulus at 80°C is 4.0 × 10⁻⁶ 5 An adhesive described in any of [8] to

[12] , having a Pa of or less.

[14] Moisture permeability of 3000 g / m 2 • An adhesive that is 2 days or longer and is one of the adhesives listed in [8] to

[13] .

[15] An adhesive according to any of [8] to

[14] , wherein the adhesive strength to human skin is 0.2 to 1 N / 15 mm.

[16] An adhesive according to any one of [8] to

[15] , wherein the difference between the adhesive strength to phenolic resin and the adhesive strength to human skin is 2 N / 15 mm or more.

[17] Substrate and A bonding material having an adhesive layer provided on the surface of the substrate, the adhesive layer containing the adhesive described in any of [8] to

[16] .

[18] Substrate and An adhesive tape having an adhesive layer provided on at least one surface of the substrate, the adhesive layer containing the adhesive described in any of [8] to

[16] .

[19] The wearable device itself, A wearable device having an adhesive layer containing an adhesive according to any one of [8] to

[16] provided on at least a portion of the surface to be adhered to the wearable device body.

[20] Wearable device body and A wearable device kit comprising an adhesive according to any one of [8] to

[16] , a bonding material according to

[17] , or an adhesive tape according to

[18] for attaching the wearable device body to the skin. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a urethane prepolymer, adhesive, patch, adhesive tape, wearable device, and wearable device kit that have excellent moisture permeability and achieve both low adhesion to the skin and high adhesion to the substrate. [Modes for carrying out the invention]

[0010] The definitions and meanings of terms used in this specification are as follows: An "oxyalkylene polymer" is a polymer that has polyoxyalkylene chains. Furthermore, the repeating unit based on alkylene oxide is called an "alkylene oxide unit." "Hydroxy-terminated urethane prepolymer" refers to a compound obtained by reacting an organic compound having hydroxyl groups with a diisocyanate compound, having hydroxyl groups at least part of the ends of its molecular chains and having urethane bonds within its molecular chains. Furthermore, in this specification, "isocyanate-terminated urethane prepolymer" refers to a compound obtained by reacting an organic compound having two or more hydroxyl groups in one molecule with a polyisocyanate compound, having isocyanate groups at least part of the ends of its molecular chains and having urethane bonds within its molecular chains. The number-average molecular weight (hereinafter referred to as "Mn") and molecular weight distribution (hereinafter referred to as "Mw / Mn") of the oxyalkylene polymer are values ​​obtained by the method described below. Several monodisperse polypropylene glycol polymers with different degrees of polymerization were measured using a commercially available GPC analyzer (HLC-8320GPC, manufactured by Tosoh Corporation) as standard samples for molecular weight measurement. A calibration curve was created based on the relationship between the molecular weight and retention time of the polypropylene glycol. The oxyalkylene polymer, which was the sample to be measured, was diluted to 0.5% by mass with tetrahydrofuran, passed through a 0.5 μm filter, and then measured using the above GPC analyzer. The Mn and mass-average molecular weight (hereinafter referred to as Mw) of the sample were determined by computer analysis of the GPC spectrum of the sample using the above calibration curve. The molecular weight distribution is the value obtained by dividing Mw by Mn. The degree of unsaturation of the oxyalkylene polymer was measured according to the method of JIS-K1557-6. The hydroxyl value of oxyalkylene polymers is a value measured and calculated according to the titration method specified in JIS K 0070:1992, "Test methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0011] [Hydroxy-terminated urethane prepolymer] The hydroxyl-terminated urethane prepolymer of the present invention is obtained by reacting oxyalkylene polymer A, oxyalkylene polymer B, and a diisocyanate compound. Urethane bonds are formed between oxyalkylene polymer A and oxyalkylene polymer B and the diisocyanate compound through the reaction of hydroxyl groups of oxyalkylene polymer A and oxyalkylene polymer B with isocyanate groups of the diisocyanate compound. Of the hydroxyl groups of oxyalkylene polymer A and oxyalkylene polymer B, those that remain unreacted with the isocyanate groups of the diisocyanate compound become the hydroxyl groups at the ends of the molecular chains of the urethane prepolymer.

[0012] <Oxyalkylene Polymer A> Oxyalkylene polymer A (hereinafter also referred to as polymer A) is an oxyalkylene polymer having an average of 2.1 to 3 hydroxyl groups per molecule.

[0013] The average number of hydroxyl groups per molecule of oxyalkylene polymer A is not particularly limited as long as it is between 2.1 and 3, but 2.2 to 2.8 is more preferable. When the average number of hydroxyl groups is within the above range, it is easier to achieve both superior moisture permeability and low adhesion to the skin and high adhesion to the substrate. When the average number of hydroxyl groups of oxyalkylene polymer A is within the range of 2.1 to 3, the resulting adhesive tends to have an appropriate level of adhesion to the skin and to the substrate, and it is preferable that there is less adhesive residue when peeled off the skin. Adhesive residue refers to the residue of adhesive that remains on the skin when the adhesive is applied to the skin and then peeled off.

[0014] The average number of hydroxyl groups per molecule of oxyalkylene polymer A is: 13 This was calculated by identifying the type and molar ratio of the initiator using 1C-NMR (nuclear magnetic resonance). 13 13C-NMR analysis reveals characteristic peaks for initiators, allowing for the identification of the initiator type and molar ratio based on the peak location and area. Typically, the number of hydroxyl groups per molecule of an oxyalkylene polymer matches the number of hydroxyl groups per molecule of the initiator used in its synthesis. For example, when glycerin is used as the initiator to synthesize an oxyalkylene polymer, an oxyalkylene polymer with 3 hydroxyl groups per molecule is usually obtained. Similarly, when pentaerythritol is used as the initiator to synthesize an oxyalkylene polymer, an oxyalkylene polymer with 4 hydroxyl groups per molecule is usually obtained. Furthermore, when dipropylene glycol is used as the initiator to synthesize an oxyalkylene polymer, an oxyalkylene polymer with 2 hydroxyl groups per molecule is usually obtained. The average number of hydroxyl groups per molecule of oxyalkylene polymer A is calculated from the number of hydroxyl groups per molecule based on the type of initiator and the mole fraction of the initiator. For example, if glycerin is 30 mol% and dipropylene glycol is 70 mol%, the average number of hydroxyl groups is 3 × 0.3 + 2 × 0.7 = 2.3.

[0015] The alkylene oxide used in synthesizing oxyalkylene polymer A is not particularly limited, but alkylene oxides having 2 to 5 carbon atoms are preferred, one or more selected from ethylene oxide and propylene oxide are more preferred, and propylene oxide alone or a combination of ethylene oxide and propylene oxide is even more preferred. When propylene oxide and ethylene oxide are used together, the arrangement of ethylene oxide units and propylene oxide units may be random or in blocks. When ethylene oxide and other alkylene oxides are used in combination as alkylene oxides, the molar ratio of ethylene oxide to other alkylene oxides is not particularly limited, but it is preferable that the molar ratio is such that the ethylene oxide unit content of oxyalkylene polymer A is within the range described later. The higher the ethylene oxide unit content, the better the hydrophilicity of oxyalkylene polymer A, and the lower the ethylene oxide unit content, the lower the crystallinity of oxyalkylene polymer A tends to be.

[0016] The ethylene oxide unit content of oxyalkylene polymer A is not particularly limited, but is preferably 0 to 80% by mass, more preferably 0 to 60% by mass, even more preferably 5 to 55% by mass, and even more preferably 12 to 50% by mass. When the ethylene oxide unit content of oxyalkylene polymer A is within this range, oxyalkylene polymer A tends to become amorphous, making it easier to handle, and the resulting adhesive has more appropriate adhesion to the skin.

[0017] The ethylene oxide unit content of oxyalkylene polymer A is, 13 This was calculated by determining the monomer composition of the oxyalkylene chain using 1C-NMR. For example, if oxyalkylene polymer A is a polyol composed of propylene oxide units and ethylene oxide units, the ethylene oxide unit content can be determined from the area ratio of the signal of the methyl group in the propylene oxide unit to the signal of the methylene group in the propylene oxide unit and the ethylene oxide unit.

[0018] The manganese (Mn) of oxyalkylene polymer A is not particularly limited, but is preferably between 1,000 and 50,000, and more preferably between 5,000 and 30,000. When the Mn of oxyalkylene polymer A is within this range, the resulting adhesive has better flexibility. In addition, the adhesive strength and residue of the resulting adhesive are more appropriate. When two or more types of oxyalkylene polymer A are included, it is preferable that the Mn, Mw / Mn, degree of unsaturation, and average number of functional groups of each oxyalkylene polymer A are within the above range.

[0019] It is preferable that oxyalkylene polymer A contains oxyalkylene polymer a (hereinafter referred to as "polymer a") having 3 hydroxyl groups per molecule and oxyalkylene polymer b (hereinafter referred to as "polymer b") having 2 hydroxyl groups per molecule. When oxyalkylene polymer A contains both polymer a and polymer b, it is easier to achieve a more appropriate level of adhesion to the skin and to the substrate.

[0020] Polymerization a may consist of two or more types. The ethylene oxide unit content of polymer a is not particularly limited, but is preferably 0% by mass or more, more preferably 10 to 80% by mass, even more preferably 15 to 60% by mass, and even more preferably 15 to 30% by mass. When two or more types of polymer a are included, it is preferable that the ethylene oxide unit content calculated by their weighted average is within the above range. Furthermore, the Mn of polymer a is not particularly limited, but is preferably 1000 to 50000, more preferably 5000 to 30000, and even more preferably 8000 to 25000. When two or more types of polymer a are included, it is preferable that the Mn of each polymer a is within the above range. The Mw / Mn ratio of polymer a is not particularly limited, but is preferably less than 1.20, more preferably less than 1.13, and particularly preferably less than 1.10. By setting the molecular weight distribution of polymer a to less than 1.20, the reactivity tends to be good, the urethane prepolymer described later can be produced more efficiently, and the viscosity of the resulting urethane prepolymer tends to be lower. The degree of unsaturation of polymer a is preferably 0.015 meq / g or less, more preferably 0.013 meq / g or less, and even more preferably 0.008 meq / g or less. The degree of unsaturation of oxyalkylene polymer a may be zero. If the degree of unsaturation of polymer a is below the above upper limit, the curability of the resulting prepolymer is better, and adhesive residue on the skin is further reduced. When two or more oxyalkylene polymers a are included, it is preferable that the Mn, Mw / Mn, and degree of unsaturation of each polymer a are within the above range.

[0021] Polymer b may consist of two or more types. The ethylene oxide unit content of polymer b is not particularly limited, but is preferably 0% by mass or more, more preferably 10 to 80% by mass or more, even more preferably 15 to 60% by mass, and even more preferably 15 to 30% by mass. When two or more types of polymer b are included, it is preferable that the ethylene oxide unit content calculated by their weighted average is within the above range. Furthermore, the Mn of oxyalkylene polymer b is not particularly limited, but is preferably 1000 to 50000, more preferably 5000 to 30000, and even more preferably 8000 to 25000. When two or more polymers b are included, it is preferable that the Mn of each polymer b is within the above range. The Mw / Mn ratio of polymer b is not particularly limited, but is preferably less than 1.20, more preferably less than 1.13, and particularly preferably less than 1.10. By setting the molecular weight distribution of oxyalkylene polymer a to less than 1.20, the reactivity tends to be good, the urethane prepolymer described later can be produced more efficiently, and the viscosity of the resulting urethane prepolymer tends to be lower. 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 0.008 meq / g or less. The degree of unsaturation of oxyalkylene polymer b may be zero. If the degree of unsaturation of polymer b is below the above upper limit, the curability of the resulting prepolymer is better, and adhesive residue on the skin is further reduced. When two or more polymers b are included, it is preferable that the Mn, Mw / Mn, and degree of unsaturation of each polymer b are within the above range.

[0022] The proportion of polymer a relative to the total mass of polymer a and polymer b is not particularly limited, but is preferably 5 to 95% by mass, more preferably 10 to 80% by mass, and even more preferably 15 to 60% by mass. When the proportion of polymer a relative to the total mass of polymer a and polymer b is within this range, the resulting adhesive leaves less residue when peeled from the skin, which is preferable.

[0023] The ratio of polymer a to polymer b contained in oxyalkylene polymer A can be calculated as follows. The hydroxyl value of oxyalkylene polymer A is calculated according to the titration method specified in JIS K 0070:1992, "Test methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products." Furthermore, the number-average molecular weight of oxyalkylene polymer A (in terms of oxyalkylene polymer equivalent) is calculated by measuring GPC and analyzing the calibration curve obtained using the oxyalkylene polymer as a standard substance. The hydroxyl value and Mn obtained as described above are applied to the formula "(hydroxyl value × Mn) / 56100" to calculate the average number of hydroxyl groups. Next, 13 By using 1C-NMR to confirm, for example, the presence or absence of tertiary carbons derived from glycerin, the type of initiator contained in oxyalkylene polymer A is identified. Then, by determining the content ratio of units derived from each initiator based on the above information on the average number of functional groups and the type of initiator, the ratio of polymer a to polymer b contained in oxyalkylene polymer A is calculated.

[0024] Oxyalkylene polymer A may contain oxyalkylene polymers other than polymer a, polymer b, and oxyalkylene polymer B, as long as the average number of hydroxyl groups per molecule is 2.1 to 3. Examples of such oxyalkylene polymers other than oxyalkylene polymer a, oxyalkylene polymer b, and oxyalkylene polymer B include oxyalkylene polymers with 4 or more hydroxyl groups per molecule and oxyalkylene polymers with 1 hydroxyl group per molecule and a manganese content of less than 5000. In oxyalkylene polymer A, the total mass ratio of polymer a and polymer b is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass.

[0025] The method for producing oxyalkylene polymer A is not particularly limited, but examples include a method in which polymer a, having 3 hydroxyl groups per molecule, and polymer b, having 2 hydroxyl groups per molecule, are synthesized separately and then mixed, and a method in which oxyalkylene polymer A is synthesized as a mixture of polymer a, having 3 hydroxyl groups per molecule, and polymer b, having 2 hydroxyl groups per molecule.

[0026] To synthesize oxyalkylene polymer A, it is preferable to perform ring-opening addition of an alkylene oxide to an initiator having two or more hydroxyl groups in one molecule, in the presence of a catalyst.

[0027] To synthesize polymer b, an initiator having two hydroxyl groups per molecule is used. The initiator having two hydroxyl groups per molecule for synthesizing polymer b is preferably one or more selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol, more preferably one or more selected from propylene glycol and dipropylene glycol, and even more preferably propylene glycol. Propylene glycol is readily available at low cost, thus reducing the synthesis cost of polymer b.

[0028] To synthesize polymer a, an initiator having three hydroxyl groups in one molecule is used. Glycerin is preferred as the initiator for synthesizing polymer a. Glycerin is readily available at low cost, which can reduce the cost of synthesizing oxyalkylene polymer a.

[0029] To synthesize an oxyalkylene polymer A that may contain four or more hydroxyl groups per molecule, an initiator having four or more hydroxyl groups per molecule is used. Examples of initiators having four or more hydroxyl groups per molecule include, but are not limited to, polyhydric alcohols with four or more hydroxyl groups, such as diglycerin, pentaerythritol, dipentaerythritol, and tripentaerythritol, as well as sugars or their derivatives, such as glucose, sorbitol, dextrose, fructose, sucrose, and methyl glucoside.

[0030] To synthesize an oxyalkylene polymer A having one hydroxyl group per molecule, an initiator having one hydroxyl group per molecule is used. The initiator having one hydroxyl group per molecule is the same as the initiator that can be used when synthesizing oxyalkylene polymer B, which will be described later. However, the Mn of the oxyalkylene polymer A having one hydroxyl group per molecule is less than 5000.

[0031] To synthesize oxyalkylene polymer A as a mixture of oxyalkylene polymers with different numbers of hydroxyl groups per molecule, initiators with different numbers of hydroxyl groups per molecule are mixed and used. However, the type and amount of initiator used should be set so that the average number of hydroxyl groups in the resulting oxyalkylene polymer is between 2.1 and 3.

[0032] The alkylene oxide used in the synthesis of polymer a, polymer b, oxyalkylene polymers with 4 or more hydroxyl groups per molecule, and oxyalkylene polymers with 1 hydroxyl group per molecule and a Mn of less than 5000 is the same as the alkylene oxide used in the synthesis of oxyalkylene polymer A described above.

[0033] Conventional known catalysts can be used as catalysts for ring-opening addition polymerization of alkylene oxides as initiators. Examples include alkaline catalysts such as KOH, transition metal compound-porphyrin complex catalysts such as complexes obtained by reacting organoaluminum compounds with porphyrins, complex metal cyanide catalysts, and catalysts consisting of phosphazene compounds. When obtaining oxyalkylene polymer A using a complex metal cyanide catalyst, it is preferable because the molecular weight distribution of the resulting oxyalkylene polymer A can be narrowed, making it easier to obtain oxyalkylene polymer A with low viscosity. As the composite metal cyanide complex, conventionally known compounds can be used, and as the method for producing a polymer using the composite metal cyanide complex, a conventionally known method can also be adopted. For example, the compounds and production methods disclosed in International Publication No. 2003 / 062301, International Publication No. 2004 / 067633, JP-A No. 2004-269776, JP-A No. 2005-015786, International Publication No. 2013 / 065802, JP-A No. 2015-010162, etc. can be used. As the method for obtaining the oxyalkylene polymer A by subjecting an alkylene oxide to ring-opening addition polymerization to an initiator, a conventionally known method can be adopted. For example, the production methods disclosed in International Publication No. 2011 / 125951, Japanese Patent No. 5648797, etc. can be used.

[0034] <Oxyalkylene polymer B> The oxyalkylene polymer B is an oxyalkylene polymer having 1 hydroxyl group per molecule and a Mn of 5000 or more. The Mn of the oxyalkylene polymer B is preferably more than 5000.

[0035] The number of hydroxyl groups per molecule of the oxyalkylene polymer B is 1. The number of hydroxyl groups of the oxyalkylene polymer B 13 can be measured using C-NMR. Specifically, 13 From the peaks obtained by C-NMR, the type of initiator is specified, and if the initiator has 1 hydroxyl group in one molecule, it can be seen that the number of hydroxyl groups is 1.

[0036] The oxyalkylene polymer B has a structure in which one or more alkylene oxides are subjected to ring-opening addition to an initiator having 1 hydroxyl group in one molecule. The number of carbon atoms of the alkylene oxide is not particularly limited, but 2 to 5 are preferable, and 2 to 3 are more preferable. When two or more alkylene oxides are subjected to ring-opening addition to the initiator, the sequence of units derived from each alkylene oxide may be random or block. As the alkylene oxide, it is preferable to use propylene oxide alone or in combination with propylene oxide and ethylene oxide. When propylene oxide and ethylene oxide are used in combination, the molar ratio of propylene oxide to ethylene oxide is not particularly limited, but it is preferable to keep the ethylene oxide unit content of oxyalkylene polymer B within the range described later. The higher the propylene oxide unit content, the lower the crystallinity of oxyalkylene polymer B tends to be, and the higher the ethylene oxide unit content, the higher the hydrophilicity of oxyalkylene polymer B tends to be.

[0037] There may be two or more types of oxyalkylene polymer B. The ethylene oxide unit content of oxyalkylene polymer B is not particularly limited, but is preferably 0 to 80% by mass, more preferably 0 to 60% by mass, even more preferably 5 to 55% by mass, and even more preferably 10 to 50% by mass. When the ethylene oxide unit content of oxyalkylene polymer B is within this range, the adhesive properties and moisture permeability of the resulting adhesive to the skin become more appropriate. The ethylene oxide unit content of oxyalkylene polymer B can be calculated in the same way as oxyalkylene polymer A. When two or more types of oxyalkylene polymer B are included, it is preferable that the ethylene oxide unit content calculated by their weighted average is within the above range.

[0038] The manganese (Mn) of oxyalkylene polymer B is not particularly limited as long as it is 5000 or more, but is preferably between 5000 and 50000, more preferably between 5000 and 50000, and even more preferably between 8000 and 30000. When the Mn of oxyalkylene polymer B is 5000 or more, the flexibility of the resulting adhesive and its conformability to the skin when applied to the skin are improved. When the Mn of oxyalkylene polymer B is greater than 5000, the flexibility of the resulting adhesive is further improved. In addition, the conformability to the skin when the resulting adhesive is applied to the skin is further improved. The Mw / Mn ratio of oxyalkylene polymer B is not particularly limited, but is preferably less than 1.20, more preferably less than 1.13, and particularly preferably less than 1.10. By setting the molecular weight distribution of oxyalkylene polymer B to less than 1.20, the reactivity tends to be good, the urethane prepolymer described later can be produced more efficiently, and the viscosity of the resulting urethane prepolymer tends to be lower. The degree of unsaturation of oxyalkylene polymer B is preferably 0.015 meq / g or less, more preferably 0.013 meq / g or less, and even more preferably 0.008 meq / g or less. The degree of unsaturation of oxyalkylene polymer B may be zero. If the degree of unsaturation of oxyalkylene polymer B is below the above upper limit, the curability of the resulting prepolymer will be better, and adhesive residue on the skin will be further reduced. The Mn of oxyalkylene polymer B can be measured in the same way as oxyalkylene polymer A. When two or more types of oxyalkylene polymer B are included, it is preferable that the Mn, Mw / Mn, and degree of unsaturation of each oxyalkylene polymer B are within the above range.

[0039] To synthesize oxyalkylene polymer B, it is preferable to perform ring-opening addition of an alkylene oxide to an initiator having one hydroxyl group per molecule in the presence of a catalyst. As an initiator having one hydroxyl group per molecule for synthesizing oxyalkylene polymer B, a monohydric alcohol having 2 to 4 carbon atoms is preferred, more preferably at least one selected from the group consisting of propanol (n-propyl alcohol), 2-propanol (isopropyl alcohol), 1-butanol (n-butyl alcohol), 2-butanol (sec-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), and 2-methyl-2-propanol (tert-butyl alcohol), and even more preferably at least one selected from the group consisting of 1-butanol (n-butyl alcohol), 2-butanol (sec-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), and 2-methyl-2-propanol (tert-butyl alcohol). Alcohols having 2 to 4 carbon atoms are available at low cost, which can reduce the synthesis cost of oxyalkylene polymer B.

[0040] As with oxyalkylene polymer A, it is preferable to use a DMC catalyst. However, since the Mn of oxyalkylene polymer B is 5000 or more, the reaction conditions such as the reaction time should be adjusted so that the Mn of the synthesized oxyalkylene polymer is 5000 or more.

[0041] <Diisocyanate compounds> The diisocyanate compound used to obtain the hydroxyl-terminated urethane prepolymer of the present invention by reacting it with the above-mentioned oxyalkylene polymer A and the above-mentioned oxyalkylene polymer B is not particularly limited as long as it is an organic compound having two isocyanate groups in one molecule.

[0042] The diisocyanate compound may be at least one selected from the group consisting of aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, aromatic diisocyanate compounds, and aromatic aliphatic diisocyanate compounds.

[0043] Aliphatic diisocyanate compounds include, but are not limited to, linear aliphatic diisocyanates such as tetramethylene diisocyanate, dodecamethylene diisocyanate, and hexamethylene diisocyanate (HDI), as well as branched aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate. Linear aliphatic diisocyanates are preferred as aliphatic diisocyanate compounds because they result in a higher glass transition temperature, superior tensile strength, and better elongation at break of the resulting polyurethane (adhesive). Linear aliphatic diisocyanates having 4 to 8 carbon atoms are more preferred, and hexamethylene diisocyanate (HDI) is even more preferred.

[0044] Examples of alicyclic diisocyanate compounds include, but are not limited to, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis(isocyanate-methyl)cyclohexane. As for the alicyclic diisocyanate compound, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, or both, are preferred, with isophorone diisocyanate being more preferred, because they result in a higher glass transition temperature, superior tensile strength, and better elongation at break of the resulting polyurethane (adhesive).

[0045] Aromatic diisocyanate compounds include, but are not limited to, tolylene diisocyanate (TDI), 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dibenzyle diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate. Diphenylmethane diisocyanate is preferred as the aromatic diisocyanate compound, and 4,4'-diphenylmethane diisocyanate (MDI) is more preferred, as it results in a higher glass transition temperature for the resulting polyurethane.

[0046] Aromatic aliphatic diisocyanate compounds include, but are not limited to, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α,α,α,α-tetramethylxylylene diisocyanate. As the aromatic aliphatic diisocyanate compound, α,α,α,α-tetramethylxylylene diisocyanate is preferred because it yields a superior elongation of the resulting polyurethane at fracture.

[0047] The diisocyanate compound used in the production of the hydroxyl-terminated urethane prepolymer of the present invention is preferably one or more selected from the group consisting of aliphatic diisocyanate compounds and alicyclic diisocyanate compounds, more preferably an aliphatic diisocyanate compound, even more preferably an aliphatic diisocyanate compound having 4 to 6 carbon atoms, even more preferably one or more selected from the group consisting of HDI and modified forms thereof, and even more preferably HDI or an isocyanurate modified form of HDI.

[0048] As the diisocyanate compound for producing the hydroxyl-terminated urethane prepolymer of the present invention, a bifunctional isocyanate-terminated urethane prepolymer obtained by prepolymerizing the above-mentioned aliphatic diisocyanate compound, alicyclic diisocyanate compound, aromatic diisocyanate compound, or aromatic aliphatic diisocyanate compound with a diol may be used. Diols for producing isocyanate-terminated urethane prepolymers include, but are not limited to, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. From the viewpoint of achieving a higher glass transition temperature for the resulting polyurethane (adhesive), one or more diols selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol are preferred, with propylene glycol being more preferred. The isocyanate index for the production of isocyanate-terminated urethane prepolymers shall be greater than 100. The isocyanate index is the value obtained by dividing the number of moles of isocyanate groups in a diisocyanate compound by the number of moles of hydroxyl groups in a diol and multiplying by 100. Examples of commercially available bifunctional isocyanate-terminated urethane prepolymers include, but are not limited to, Duranate D101, Duranate D201, and Duranate A201H (all manufactured by Asahi Kasei Corporation).

[0049] <Method for producing hydroxyl-terminated urethane prepolymer> The method for producing the hydroxyl-terminated urethane prepolymer of the present invention is not particularly limited, but one method is to react oxyalkylene polymer A and oxyalkylene polymer B with a diisocyanate compound in a ratio such that the isocyanate index is less than 100. The isocyanate index is the value obtained by dividing the number of moles of isocyanate groups in the diisocyanate compound by the total number of moles of hydroxyl groups in oxyalkylene polymer A and oxyalkylene polymer B and multiplying by 100. The content of oxyalkylene polymer A relative to the total mass of oxyalkylene polymer A and oxyalkylene polymer B is not particularly limited, but is preferably 10 to 95% by mass, and more preferably 20 to 80% by mass. When the content of oxyalkylene polymer A relative to the total mass of oxyalkylene polymer A and oxyalkylene polymer B is within this range, a better balance can be maintained between the permeability of the resulting adhesive and its adhesion to the skin and substrate. The average number of hydroxyl groups in the hydroxyl-terminated urethane prepolymer is preferably less than 3.0, more preferably 1.7 to 2.9, even more preferably 1.7 to 2.5, and particularly preferably 1.8 to 2.4. When the average number of hydroxyl groups in the hydroxyl-terminated urethane prepolymer is within this range, a better balance can be maintained between the permeability of the resulting adhesive and its adhesion to the skin and substrate. The "average number of hydroxyl groups f" of the hydroxyl-terminated urethane prepolymer is the value obtained by the following formula (I). f=(1000f n / Mn) / [{(1000 / Mn)-(Unsaturation degree / f n )}+unsaturation] ···(I) However, f n This is the number of active hydrogen atoms per molecule of initiator used as a raw material when producing the oxyalkylene polymer. Furthermore, when multiple oxyalkylene polymers are used in combination, the "average number of functional groups f" ave This can be calculated using the following formula (II). f ave =Σ(f i ×W i / Mn i ) / Σ(W i / Mn i ) ···(II) However, f i W is the number of active hydrogen atoms per molecule of initiator used as a raw material in each oxyalkylene polymer. i This is the mass parts of each oxyalkylene polymer, Mn i This represents the Mn in each oxyalkylene polymer.

[0050] A catalyst may be used as needed in the production of the hydroxyl-terminated urethane prepolymer of the present invention. It is preferable to use one or more catalysts selected from tertiary amine compounds and organometallic compounds. Examples of tertiary amine compounds include, but are not limited to, triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7(DBU). The organometallic compound is preferably one or more selected from tin-based compounds and non-tin-based compounds. Examples of tin compounds include, but are not limited to, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate. Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanate, 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; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate. Catalysts can be used individually or in combination of two or more types. When using a catalyst, the amount of catalyst used is not particularly limited, but it is preferably 0.01 to 1.0 parts by mass per 100 parts by mass of the total of oxyalkylene polymer A and oxyalkylene polymer B and the diisocyanate compound.

[0051] A solvent may be used as needed in the production of the hydroxyl-terminated urethane prepolymer of the present invention. The solvent is preferably one or more selected from ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, and aromatic hydrocarbons such as toluene and xylene. Two or more solvents may be used in combination. When using a solvent, the amount of solvent used is not particularly limited, but 50 to 500 parts by mass is preferred per 100 parts by mass of the total of the oxyalkylene polymer and the diisocyanate compound.

[0052] Examples of methods for producing the hydroxyl-terminated urethane prepolymer of the present invention include the following methods. Manufacturing method 1: A method of charging a diisocyanate compound, oxyalkylene polymer A and oxyalkylene polymer B, a catalyst and a solvent together into a flask. Manufacturing method 2: A method in which oxyalkylene polymer A and oxyalkylene polymer B, a catalyst, and a solvent are placed in a flask, and a diisocyanate compound is added dropwise thereto. Of these methods, manufacturing method 2 is preferred because it preferentially reacts with low molecular weight components in the raw materials, narrows the molecular weight distribution, and makes reaction control easier.

[0053] The reaction temperature is preferably below 100°C, and more preferably between 85°C and 95°C. Lowering the reaction temperature below 100°C makes it easier to suppress side reactions other than the urethane reaction, thus making it easier to obtain the desired prepolymer.

[0054] The isocyanate index for producing the hydroxyl-terminated urethane prepolymer of the present invention is preferably 30 to 95, more preferably 40 to 95, and even more preferably 50 to 95. When the isocyanate index is within this range, a hydroxyl-terminated urethane prepolymer with an appropriate molecular chain length can be produced, thus improving productivity.

[0055] After the reaction is complete, it is preferable to add a reaction stopper to deactivate the catalyst. Examples of reaction stoppers include, but are not limited to, acetylacetone. Two or more reaction stoppers may be used in combination.

[0056] <Ethylene oxide unit content in hydroxyl-terminated urethane prepolymer> The ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer of the present invention is 10% by mass or more, preferably 10 to 80% by mass, and more preferably 12 to 50% by mass. When the ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer of the present invention is 10% by mass or more, the resulting adhesive can achieve both low tackiness to the skin and high tackiness to the substrate.

[0057] [Adhesive] The adhesive of the present invention is an adhesive obtained by reacting an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3, an oxyalkylene polymer B having 1 hydroxyl group per molecule and a number average molecular weight of 5000 or more, with a polyisocyanate compound, and having an ethylene oxide unit content of 10% by mass or more, or an adhesive obtained by reacting the hydroxyl-terminated urethane prepolymer of the present invention with a curing agent (hereinafter sometimes simply referred to as "curing agent") containing a polyisocyanate compound having 3 or more isocyanate groups per molecule. The polyisocyanate compounds mentioned above are compounds having two or more isocyanate groups in one molecule, and include the diisocyanate compounds described above and the polyisocyanate compounds having three or more isocyanate groups in one molecule, as described later.

[0058] The ethylene oxide unit content in the adhesive of the present invention is 10% by mass or more, preferably 10 to 80% by mass, and more preferably 12 to 50% by mass. When the ethylene oxide unit content in the adhesive of the present invention is 10% by mass or more, the moisture permeability is improved, the adhesion to highly polar substrates is further enhanced, and the stratum corneum is less likely to peel off in a wet state. The storage modulus of the adhesive of the present invention at 25°C is 1.0 × 10⁻⁶ 4 Pa~5.0×10 5 Pa is preferred, 2.0 × 10 4 Pa~4.8×10 5 Pa is more preferable, 2.0 × 10 4 Pa~3.0×10 5 Pa is even more preferred, 2.0 × 10 4 Pa~2.5×10 5 Pa is particularly preferred, 2.0 × 10 4 Pa~1.0×10 5 Pa is most preferred. When the storage modulus of the adhesive of the present invention is within the above range, adhesion to the skin is improved, less adhesive residue is left behind, and better skin adhesion is obtained. The storage modulus of the adhesive of the present invention at 80°C is 4.0 × 10⁻⁶ 5 Preferably Pa or less, 5.0 × 10 2 Pa or more 3.0×10 5 Preferably less than Pa, 1.0 × 10 3 Pa~6.0×10 4 Pa is more preferred, 1.0 × 10 3 Pa~4.0×10 4 Pa is even more preferred, 2.0 × 10 3 Pa~1.0×10 4 Pa is particularly preferred. When the storage modulus of the adhesive of the present invention is within the above range, adhesion to the skin is improved, less adhesive residue is left behind, and better skin adhesion is obtained.

[0059] <Method for manufacturing adhesive> A method for producing an adhesive by reacting the hydroxyl-terminated urethane prepolymer of the present invention with a curing agent will be described.

[0060] The curing agent may contain, in addition to a polyisocyanate compound having three or more isocyanate groups in one molecule, a polyisocyanate compound (diisocyanate compound) having two isocyanate groups in one molecule. Examples of the diisocyanate compounds mentioned above include the diisocyanate compounds described above and the bifunctional isocyanate-terminated urethane prepolymers described above. Examples of the polyisocyanate compounds having three or more isocyanate groups in one molecule include isocyanurate modified versions of the diisocyanate compounds described above, biuret modified versions of the diisocyanate compounds described above, allophanate modified versions of the diisocyanate compounds described above, and trifunctional or higher isocyanate-terminated urethane prepolymers (adduct modified versions) obtained by reacting the diisocyanate compounds described above with polyols having three or more hydroxyl groups in one molecule. An example of an isocyanurate modified version is Coronate HX (manufactured by Tosoh Corporation). An example of a biuret modified version is Duranate 24A-100 (manufactured by Asahi Kasei Corporation). Examples of commercially available isocyanate-terminated urethane prepolymers with three or more functionalities include, but are not limited to, Coronate L, Coronate L-55E, and Coronate L-45E (all manufactured by Tosoh Corporation).

[0061] The isocyanate index when producing the adhesive of the present invention by reacting a hydroxyl-terminated urethane prepolymer with a curing agent is greater than 100, and more preferably between 105 and 160. The isocyanate index is the value obtained by dividing the number of moles of isocyanate groups in the curing agent by the number of moles of hydroxyl groups in the hydroxyl-terminated urethane prepolymer and multiplying by 100.

[0062] When producing the adhesive of the present invention by reacting a hydroxyl-terminated urethane prepolymer with a curing agent, a catalyst may be used as needed. The catalyst described above is preferred. The amount of catalyst used is preferably 0.01 to 1.0 parts by mass per 100 parts by mass of the total of the hydroxyl-terminated urethane prepolymer and curing agent. After the reaction is complete, it is preferable to add a reaction stopper to deactivate the catalyst.

[0063] When producing the adhesive of the present invention by reacting a hydroxyl-terminated urethane prepolymer with a curing agent, a solvent may be used as needed. The solvent described above is preferred. The amount of solvent used is preferably 50 to 500 parts by mass per 100 parts by mass of the total of the hydroxyl-terminated urethane prepolymer and curing agent.

[0064] The temperature at which the hydroxyl-terminated urethane prepolymer reacts with the curing agent is preferably less than 100°C, and more preferably 85 to 95°C.

[0065] A method for producing an adhesive by reacting the above-mentioned oxyalkylene polymer A, the above-mentioned oxyalkylene polymer B, and a polyisocyanate compound will be described.

[0066] In this manufacturing method, the polyisocyanate compound can be selected from polyisocyanate compounds having two isocyanate groups in one molecule and polyisocyanate compounds having three or more isocyanate groups in one molecule. For example, as the polyisocyanate compound to be reacted with the oxyalkylene polymer A and the oxyalkylene polymer B, one or more of the diisocyanate compounds described above and the polyisocyanate compounds that can be used as curing agents described above can be used.

[0067] In this manufacturing method, the isocyanate index is greater than 100, and more preferably between 105 and 160. The isocyanate index is the value obtained by dividing the number of moles of isocyanate groups in the polyisocyanate compound by the total number of moles of hydroxyl groups in oxyalkylene polymer A and oxyalkylene polymer B, and multiplying by 100.

[0068] When producing the adhesive of the present invention by reacting oxyalkylene polymer A, oxyalkylene polymer B, and a polyisocyanate compound, a catalyst may be used as needed. The catalyst described above is preferred. The amount of catalyst used is preferably 0.01 to 1.0 parts by mass per 100 parts by mass of the total of oxyalkylene polymer A, oxyalkylene polymer B, and the polyisocyanate compound. After the reaction is complete, it is preferable to add a reaction stopper to deactivate the catalyst.

[0069] When producing the adhesive of the present invention by reacting oxyalkylene polymer A, oxyalkylene polymer B, and a polyisocyanate compound, a solvent may be used as needed. The solvent described above is preferred. The amount of solvent used is preferably 50 to 500 parts by mass per 100 parts by mass of the total of oxyalkylene polymer A, oxyalkylene polymer B, and the polyisocyanate compound.

[0070] The temperature at which oxyalkylene polymers A and B are reacted with the polyisocyanate compound is preferably less than 100°C, and more preferably 85 to 95°C.

[0071] <Ingredients that may be included in adhesives> The adhesive of the present invention may further contain one or more additives, such as plasticizers, antioxidants, antistatic agents, fillers, ultraviolet absorbers, light stabilizers, and leveling agents.

[0072] The plasticizer is not particularly limited, but from the viewpoint of compatibility with other components, fatty acid esters or phosphate esters having 8 to 30 carbon atoms are preferred. When the adhesive of the present invention contains a plasticizer, the wettability of the adhesive to the adherend is further improved. Examples of fatty acid esters having 8 to 30 carbon atoms include esters of monobasic or polybasic acids having 6 to 18 carbon atoms with branched alcohols having 18 or fewer carbon atoms, esters of unsaturated fatty acids or branched acids having 14 to 18 carbon atoms with alcohols with tetrahydride or less, esters of monobasic or polybasic acids having 6 to 18 carbon atoms with polyalkylene glycols, and fatty acid esters in which the unsaturated portion has been epoxidized with a peroxide or the like.

[0073] Examples of phosphate esters include ester compounds of phosphorous acid or phosphoric acid with linear or branched alcohols having 2 to 18 carbon atoms.

[0074] The antioxidant is not particularly limited, but phenolic antioxidants, amine antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants are preferred, with phenolic antioxidants being more preferred due to their low skin sensitization potential. When the adhesive of the present invention contains an antioxidant, thermal degradation of the adhesive can be suppressed.

[0075] Specific examples of phenolic antioxidants include monophenolic antioxidants such as 2,6-di-t-butyl-p-cresol, bisphenolic antioxidants such as 2,2'-methylenebis(4-methyl-6-t-butylphenol), and high molecular weight phenolic antioxidants such as 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane.

[0076] Specific examples of amine-based antioxidants include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, a polycondensate of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidineethanol, N,N',N'',N'''-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidine-4-yl)amino)-triazine-2-yl)-4,7-diazadecane-1,10-diamine, dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine and a polycondensate of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, etc.

[0077] Specific examples of sulfur-based antioxidants include, for example, dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate. Specific examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

[0078] The antistatic agent is not particularly limited, but examples include inorganic salts, ionic liquids, and surfactants. When the adhesive of the present invention contains an antistatic agent, electrostatic discharge is suppressed, making it easier to prevent damage to electronic components incorporated in wearable devices, for example. Examples of inorganic salts include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium nitrate, sodium carbonate, and sodium thiocyanate. The ionic liquid is a salt of a cation and anion, and the cation is preferably, for example, an imidazolium ion, a pyridinium ion, or an ammonium ion. Examples of surfactants include nonionic surfactants such as glycerin fatty acid esters, anionic surfactants such as alkyl sulfonates, cationic surfactants such as tetraalkylammonium salts, and amphoteric surfactants.

[0079] Examples of fillers include talc, calcium carbonate, and titanium dioxide.

[0080] Examples of UV absorbers include benzophenone-based UV absorbers, benzotriazole-based UV absorbers, salicylic acid-based UV absorbers, oxalic acid anilide-based UV absorbers, cyanoacrylate-based UV absorbers, and triazine-based UV absorbers.

[0081] Examples of light stabilizers include hindered amine-based light stabilizers and ultraviolet light stabilizers. Examples of the above-mentioned hindered amine-based light stabilizers include, but are not limited to, [bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate], bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate. Examples of the above-mentioned UV stabilizers include, but are not limited to, nickel bis(octylphenyl) sulfide, [2,2'-thiobis(4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethylate, nickel-dibutyldithiocarbamate, benzoate-type quenchers, and nickel-dibutyldithiocarbamate.

[0082] <Moisture permeability> The moisture permeability of the adhesive of the present invention is 3000 g / m². 2 • Preferably 3500g / m² or more. 2 • More than 4000g / m² is preferable. 2 • Days or more is even preferable. The upper limit of moisture permeability is not particularly limited. The moisture permeability of the adhesive of the present invention is 1 m³ of water vapor passing through a test piece.2 Calculate the amount per day. The test specimens are prepared as follows: A hydroxyl-terminated urethane prepolymer or oxyalkylene polymer A and oxyalkylene polymer B are mixed with a curing agent and applied to a release-treated polyester film (release body, 50 μm thick) using a knife coater to a dry film thickness of 25 μm. The mixture is then cured and dried at 100°C for 3 minutes to form an adhesive layer on the release body. A coarse nylon net that does not affect the moisture permeability of the adhesive is attached to the resulting adhesive layer, and the mixture is stored in a hot air dryer at 50°C for 3 days to complete the crosslinking reaction of the adhesive layer. The release body is then peeled off to prepare a test specimen. The moisture permeability measurement was performed in a 40°C atmosphere, with the relative humidity of one space separated by the test specimen set to 90%, and the other space kept dry with a desiccant. The mass (g) of water vapor passing through the test specimen in 24 hours (1 day) was then measured. 2 Convert to a unit. The measurement is performed according to JIS Z 0208:1976 Method for testing moisture permeability of moisture-proof packaging materials (cup method). A circular test piece with a diameter approximately 10 mm larger than the inner diameter of the cup is placed over a cup containing approximately 50 g of calcium chloride desiccant. A rubber gasket and ring are then placed over the test piece and screwed in to prevent it from shifting. After measuring the total mass of this test piece, it is placed in a constant temperature and humidity chamber at 40°C and 90% RH, and the change in mass is measured at regular intervals. Moisture permeability is then calculated according to the following formula. Moisture permeability (g / m 2 (day) = W × 240000 / S However, S is the moisture permeability area (cm²). 2 ) represents the mass increase per hour (g / hr), where W represents the mass increase per hour.

[0083] <Adhesion to phenolic resin> The adhesive strength of the adhesive of the present invention to phenolic resin is preferably 2.5 N / 15 mm or more, and more preferably 3 N / 15 mm or more. The adhesive strength of the adhesive of the present invention to phenolic resin is determined according to the test method described in "10 Adhesion Strength" of the Test Methods for Adhesive Tapes and Sheets of JIS Z 0237:2009. A 15 mm wide test piece is attached to a bakelite panel (phenolic resin board, manufactured by Sumitomo Bakelite Co., Ltd., PL-1102) in a 25°C atmosphere, pressed back and forth once with a 2 kg rubber roll at a speed of 300 mm / min, left for 20 minutes, and the peeling force is measured at a peeling angle of 90 or 180 degrees and a peeling speed of 300 mm / min.

[0084] <Adhesion to human skin> The adhesive strength of the adhesive of the present invention to human skin is preferably 0.2 to 1 N / 15 mm, and more preferably 0.3 to 0.7 N / 15 mm. The adhesive strength of the adhesive of the present invention to human skin is the adhesive strength obtained by measuring it using the back of a human hand instead of a bakelite panel in the method for measuring adhesive strength to phenolic resin described above. The back of the human hand is used after being degreased with isopropyl alcohol and air-dried.

[0085] <Difference in adhesive strength between phenolic resin and human skin> The difference between the adhesive strength of the adhesive of the present invention to phenolic resin and the adhesive strength to human skin is preferably 2N / 15mm or more, and more preferably 2.5N / 15mm or more. The difference between the adhesive strength to phenolic resin and the adhesive strength to human skin was calculated using the following formula. "The difference between the adhesive strength to phenolic resin and the adhesive strength to human skin" = "Adhesion strength to phenolic resin" - "Adhesion strength to human skin"

[0086] [Two-part adhesive] The adhesive of the present invention may be a two-component adhesive comprising a first agent containing the hydroxyl-terminated urethane prepolymer of the present invention and a second agent containing a polyisocyanate compound having three or more isocyanate groups in one molecule. By mixing the first and second components, the formation of urethane bonds proceeds, resulting in an adhesive containing polyurethane. The second agent, which contains a polyisocyanate compound having three or more isocyanate groups in one molecule, is the same as the curing agent described above. The first or second agent may further contain a catalyst, a solvent, or components that may be incorporated into the adhesive described above. The first and second agents are each housed in separate containers. Various types of containers can be used, such as tubes and bottles. The two-component adhesive of the present invention may be sold in a form containing a first component and a second component, or in a form containing a first component but not a second component. In the sales form without a second component, the user can use a curing agent that they have prepared separately, which increases the user's flexibility.

[0087] [Adhesive material] The adhesive material of the present invention comprises a base material and an adhesive layer provided on the surface of the base material, the adhesive containing the adhesive of the present invention. The adhesive material of the present invention preferably has an adhesive layer provided on one side of a base film, and a release liner laminated to cover the adhesive surface of the adhesive layer so as to be removable.

[0088] The thickness of the base film is not particularly limited, but is preferably 1 to 9 μm, and more preferably 3 to 9 μm. When the thickness of the base film is within this range, the possibility of the adhesive breaking can be reduced, and the conformability of the adhesive to the skin surface can be ensured. The material of the base film is not particularly limited, but examples include urethane polymers such as polyether urethane and polyester urethane, amide polymers such as polyether polyamide block polymer, acrylic polymers such as polyacrylate, olefin polymers such as polyethylene, polypropylene, and ethylene / vinyl acetate copolymer, and ester polymers such as polyether polyester. From the viewpoint of moisture permeability, urethane polymers or amide polymers are preferred as the material of the base film. The base film material can be used individually or in combination of two or more. Furthermore, a laminated film may be made by laminating base films manufactured from different materials. The base film can be laminated with fabrics such as woven fabrics, nonwoven fabrics, knitted fabrics, or nets. The thickness of the adhesive layer is not particularly limited, but is preferably 10 to 50 μm, and more preferably 15 to 35 μm. When the thickness of the adhesive layer is within this range, the adhesion of the adhesive layer to the skin surface becomes better.

[0089] In order to prevent contamination of the adhesive layer surface, it is preferable that the adhesive material of the present invention be covered with a release liner until use. This release liner can be one that is generally used for skin or adhesive tapes applied to the skin. Specifically, it can be one in which a release agent having release properties such as silicone resin or fluororesin is coated on the surface of high-quality paper, glassine paper, or parchment paper, or one in which a release agent having release properties such as silicone resin or fluororesin is coated on the surface of high-quality paper anchored with resin or high-quality paper laminated with polyethylene.

[0090] The adhesive material of the present invention allows for the peelable lamination of a support film on the surface of the base film opposite to the surface on which the adhesive layer is formed. The material of the support film is not particularly limited, but plastic film and paper are preferred. In particular, transparent plastic film is especially useful when fixing medical devices such as catheters, as it allows the application site to be viewed through the adhesive material while being applied to the skin. Methods such as inflation molding, extrusion lamination, lamination molding, or casting can be used to peelly laminate the support film to the back surface of the base film. The thickness of the support film varies depending on the material, but is usually preferably about 15 to 200 μm, and more preferably about 20 to 100 μm.

[0091] [Adhesive tape] The adhesive tape of the present invention comprises a base material and an adhesive layer containing the adhesive of the present invention, provided on at least one surface of the base material. In the adhesive tape of the present invention, the adhesive layer may be provided on only one surface of the substrate, or on both surfaces of the substrate.

[0092] In one embodiment of the adhesive tape of the present invention, it is preferable that an adhesive layer is provided on one side of a base film, and that a release liner is laminated to cover the adhesive surface of the adhesive layer and be removable. This embodiment is particularly referred to as a single-sided adhesive tape. The base film and release liner are the same as those in the adhesive material of the present invention. Furthermore, the thickness of the adhesive layer is the same as that of the adhesive material of the present invention. This form of adhesive tape can be used to fix an article to be fixed to the skin surface by covering at least a portion of the article with the adhesive tape.

[0093] Another embodiment of the adhesive tape of the present invention preferably has an adhesive layer provided on both sides of a base film, and a release liner laminated to cover the adhesive surface of the adhesive layer and be removable. This embodiment is specifically referred to as a double-sided adhesive tape. The base film and release liner are the same as those in the adhesive material of the present invention. Furthermore, the thickness of the adhesive layer is the same as that of the adhesive material of the present invention. This form of adhesive tape can be used to fix an article to be fixed to the skin surface, such that the adhesive tape is interposed between at least a portion of the article that is to be fixed to the skin surface and the skin surface.

[0094] A further embodiment of the adhesive tape of the present invention preferably has an adhesive layer provided on one side of a peelable base film, and a peelable liner laminated to cover the adhesive surface of the adhesive layer. This embodiment is particularly referred to as an adhesive transfer tape. The peelable base film is preferably a base film usable in the adhesive material of the present invention, coated with a release agent having release properties such as silicone resin or fluororesin on its surface. The release liner is the same as that of the adhesive material of the present invention. The thickness of the adhesive layer is the same as that of the adhesive layer in the adhesive material of the present invention. This form of adhesive tape can be used to fix an article to the skin surface, with an adhesive layer interposed between at least a portion of the article that comes into contact with the skin surface and the skin surface. Since only the adhesive layer is interposed between the article to be fixed to the skin surface and the skin surface, and no base film is present, better adhesion between the article and the skin surface can be achieved.

[0095] [Wearable devices, wearable device kits] The wearable device of the present invention comprises a wearable device body and an adhesive layer containing the adhesive of the present invention, provided on at least a portion of the surface to which the wearable device body is attached. Furthermore, the wearable device kit of the present invention includes a wearable device body and an adhesive, adhesive material, or adhesive tape of the present invention for attaching the wearable device body to the skin of a mammal.

[0096] Wearable devices are not limited to, but examples include sensors for heart rate, heart rate variability, heart rate interval, heart rate waveform, electrocardiogram, electromyography, activity level, blood pressure, body surface temperature, electroencephalogram, electroencephalogram interval, or respiratory interval.

[0097] The thickness of the adhesive layer provided on at least a portion of the surface to be attached to the wearable device body is not particularly limited, but is preferably 10 to 50 μm, and more preferably 15 to 40 μm. When the thickness of the adhesive layer is within this range, the wearable device body is less likely to fall off when attached to the skin, and the surface to which it is attached is less likely to be damaged when peeled off the skin.

[0098] The wearable device itself can also be attached to the skin using the adhesive material or adhesive tape of the present invention. The wearable device can be attached to the skin by sandwiching the device itself between the adhesive material and the skin. If the adhesive tape is single-sided adhesive tape, the wearable device can be attached to the skin by sandwiching the device between the adhesive tape and the skin. If the adhesive tape is double-sided tape, the wearable device can be attached to the skin with the adhesive tape interposed between the wearable device body and the skin. If the adhesive tape is an adhesive transfer tape, the adhesive layer can be transferred to at least a portion of the surface of the wearable device body to be attached, allowing the wearable device to be attached to the skin with only the adhesive layer interposed between the wearable device body and the skin. The skin mentioned above is preferably mammalian skin, more preferably terrestrial mammalian skin, and even more preferably human skin. Human skin may include the mucous membrane of the lips. [Examples]

[0099] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples, and various modifications are possible as long as the gist of the invention is not altered.

[0100] [Synthesis of oxyalkylene polymers] (Synthesis Example 1: Synthesis of Polymer A1) Glycerin was used as an initiator. First, 1000 g of initiator and TBA-DMC catalyst slurry were added to a pressure-resistant reaction vessel to form the reaction solution. The amount of TBA-DMC catalyst slurry added was such that the metal concentration of the TBA-DMC catalyst in the reaction solution was 46 ppm. Next, after purging the inside of the pressure-resistant reaction vessel with nitrogen, the reaction mixture was heated while stirring. When it reached 135°C, the heating was stopped, and while continuing to stir, 120 g of propylene oxide (12 parts by mass per 100 parts by mass of initiator) was supplied into the pressure-resistant reaction vessel and the reaction was carried out. After the reaction mixture temperature stopped rising, it was cooled to 135°C, and 4728g of propylene oxide was supplied into the pressure-resistant reaction vessel while stirring the reaction mixture. After confirming that the internal pressure had stopped changing and the reaction was complete, catalyst neutralization and removal were performed using a synthetic adsorbent (Kyowado 600S, manufactured by Kyowa Chemical Industry Co., Ltd.). Table 1 shows the number of hydroxyl groups, hydroxyl value, Mn, Mw / Mn, degree of unsaturation, and oxyethylene unit (hereinafter referred to as "EO unit") content of polymer A1 obtained in this way. These values ​​were measured by the method described above. The polymers obtained in the following synthesis examples are also shown in Table 1.

[0101] (Synthesis Example 2: Synthesis of Polymer A2) Polymer A2 was synthesized in the same manner as in Synthesis Example 1, except that 20% by mass of propylene oxide was replaced with ethylene oxide.

[0102] (Synthesis Example 3: Synthesis of Polymer A3) Polymer A3 was synthesized in the same manner as in Synthesis Example 1, except that 80% by mass of the propylene oxide was replaced with ethylene oxide.

[0103] (Synthesis Example 4: Synthesis of Polymer A4) Polymer A4 was synthesized in the same manner as in Synthesis Example 1, except that the initiator was changed from glycerin to propylene glycol.

[0104] (Synthesis Example 5: Synthesis of Polymer A5) Polymer A5 was synthesized in the same manner as in Synthesis Example 2, except that the initiator was changed from glycerin to propylene glycol.

[0105] (Synthesis Example 6: Synthesis of Polymer B1) Polymer B1 was synthesized in the same manner as in Synthesis Example 1, except that the initiator was changed from glycerin to 1-butanol.

[0106] (Synthesis Example 7: Synthesis of Polymer B2) Polymer B2 was synthesized in the same manner as in Synthesis Example 2, except that the initiator was changed from glycerin to 1-butanol.

[0107] [Table 1]

[0108] <Hydroxyl value> The hydroxyl value of oxyalkylene polymer A is calculated according to the titration method specified in JIS K 0070:1992, "Test methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0109] <Manufacturing of hydroxyl-terminated urethane prepolymers> [Manufacturing Example 1] In a reaction vessel equipped with a thermometer, stirrer, and condenser, 30 parts by mass of polymer A1, 70 parts by mass of polymer A4, and 100 parts by mass of toluene and ethyl acetate were added, as shown in Table 2. Next, 0.03 parts by mass of urethane catalyst (dibutyltin dilaurate, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and mixed at 40°C. Then, 1.51 parts by mass of hexamethylene diisocyanate (Duranate 50M, manufactured by Asahi Kasei Corporation, referred to as "HDI" in Table 1) was added as the diisocyanate compound, and the reaction was carried out at 80°C. The isocyanate index was 80. The reaction generated heat, the internal temperature reached approximately 80°C, and the viscosity increased over time. The reaction was carried out for 7 hours while maintaining the temperature at 80°C and adding ethyl acetate as needed to dilute the mixture, yielding a hydroxyl-terminated urethane prepolymer (also called "urethane prepolymer U1") with an average hydroxyl group count of 2.3 as a homogeneous, transparent liquid.

[0110] [Manufacturing Example 2] As shown in Table 2, a hydroxyl-terminated urethane prepolymer (also called "urethane prepolymer U2") with an average number of hydroxyl groups of 2.1 was produced in the same manner as in Production Example 1, except that 30 parts by mass of polymer A2, 40 parts by mass of polymer A5, and 30 parts by mass of polymer B1 were used instead of polymers A1 and A4, and 5.00 parts by mass of D201 (isocyanate-terminated urethane prepolymer, manufactured by Asahi Kasei Corporation) was used as the diisocyanate compound. [Manufacturing Example 3] As shown in Table 2, a hydroxyl-terminated urethane prepolymer (also called "urethane prepolymer U3") with an average number of hydroxyl groups of 2.0 was produced in the same manner as in Production Example 2, except that 30 parts by mass of polymer B2 was used instead of polymer B1, and 4.91 parts by mass of D201 was used as the diisocyanate compound. [Manufacturing Example 4] As shown in Table 2, a hydroxyl-terminated urethane prepolymer (also called "urethane prepolymer U4") with an average number of hydroxyl groups of 1.9 was produced in the same manner as in Production Example 3, except that 30 parts by mass of polymer A3 was used instead of polymer A2, and 4.77 parts by mass of D201 was used as the diisocyanate compound.

[0111] <Manufacturing of adhesives> [Example 1] As shown in Table 3, 100 parts by mass of urethane prepolymer U1 and 2 parts by mass of curing agent (Coronate L, Tosoh Corporation product name) were uniformly mixed, degassed, and then applied to a release-treated polyester film (release body, thickness 50 μm) using a knife coater to a dry film thickness of 25 μm. The mixture was then cured and dried at 100°C for 3 minutes. A 38 μm thick polyester film (support) was laminated onto the resulting adhesive layer, and the mixture was stored in a hot air dryer at 50°C for 3 days to complete the crosslinking reaction of the adhesive layer, thereby producing an adhesive. The ethylene oxide unit content in the obtained adhesive was 0% by mass.

[0112] [Example 2] As shown in Table 3, an adhesive was prepared in the same manner as in Example 1, except that urethane prepolymer U2 was used instead of urethane prepolymer U1. The ethylene oxide unit content in the obtained adhesive was 14% by mass.

[0113] [Example 3] As shown in Table 3, urethane prepolymer U3 was used as the hydroxyl-terminated urethane prepolymer. The amount of hardening agent (Coronate L, Tosoh Corporation product name) used was changed to 1.5 parts by mass. Except for one point, the adhesive was manufactured in the same manner as in Example 1. The ethylene oxide unit content in the obtained adhesive was 20% by mass. [Example 4]

[0114] As shown in Table 3, urethane prepolymer U4 was used as the hydroxyl-terminated urethane prepolymer. The amount of hardening agent (Coronate L, Tosoh Corporation product name) used was changed to 1.5 parts by mass. Except for one point, the adhesive was manufactured in the same manner as in Example 1. The ethylene oxide unit content in the obtained adhesive was 38% by mass. [Example 5] As shown in Table 3, the adhesive was prepared in the same manner as in Example 3, except that 4 parts by mass of Duranate E-402-80B (Asahi Kasei product name) was used instead of Coronate L, which is the curing agent. The ethylene oxide unit content in the obtained adhesive was 20% by mass.

[0115] [Table 2]

[0116] [Table 3]

[0117] In Table 2, the amounts of polymers, diisocyanate compounds, and catalysts are expressed in parts by mass. The "Isocyanate Index" is calculated by dividing the number of moles of isocyanate groups in the diisocyanate compound used to produce the hydroxyl-terminated urethane prepolymer by the total number of moles of hydroxyl groups in the oxyalkylene polymer and multiplying by 100. The "EO Unit Content" is the mass percentage (unit: mass%) of ethylene oxide units in the hydroxyl-terminated urethane prepolymer. "-" indicates that the component is not included. In Table 3, the amounts of urethane prepolymer and curing agent are expressed in parts by mass. "EO unit content" refers to the percentage of ethylene oxide units in the adhesive (unit: mass%). "-" indicates that the component is not included.

[0118] [Evaluation of adhesive properties] For the adhesives in Examples 1-5, we evaluated their water permeability, adhesive strength to phenolic resin, adhesive strength to human skin, the difference between the adhesive strength to phenolic resin and the adhesive strength to human skin, and storage modulus. The results are shown in Table 3. Unless otherwise specified, test specimens were prepared by cutting the adhesive material to a width of 15 mm and a length of 60 mm, with the original winding direction being the longer side (MD direction). The carrier and release element were also peeled off from the adhesive material for measurement.

[0119] <Moisture permeability> Moisture permeability is the amount of water vapor that passes through the test specimen in 24 hours (1 day) (1 cubic meter). 2 It was calculated as the mass per unit. 100 parts by mass of the manufactured urethane prepolymer and the curing agent (Coronate L (Tosoh Corporation product name) or Duranate E402-80B (Asahi Kasei Corporation product name)) were uniformly mixed in the amounts listed in Table 3, degassed, and applied to a release-treated polyester film (release body, thickness 50 μm) using a knife coater to a dry film thickness of 25 μm. Then, it was cured and dried at 100°C for 3 minutes to form an adhesive layer on the release body. A coarse nylon net that does not affect the moisture permeability of the adhesive was attached to the obtained adhesive layer, and then stored in a hot air dryer at 50°C for 3 days to complete the crosslinking reaction of the adhesive layer. The release body was peeled off and test specimens were prepared. The moisture permeability was measured in a 40°C atmosphere, with the relative humidity of the space on one side separated by the test specimen set to 90%, and the space on the other side kept dry with a desiccant. The mass (g) of water vapor passing through the test specimen in 24 hours (1 day) was then measured for 1 m³ of test material. 2 The value was calculated by converting it to a per unit. The measurement was performed according to the moisture permeability test method (cup method) of moisture-proof packaging materials, JIS Z 0208:1976. A circular test piece with a diameter approximately 10 mm larger than the inner diameter of the cup was placed over a cup containing approximately 50 g of calcium chloride desiccant, and a rubber gasket and ring were placed over it and screwed in to prevent the test piece from shifting. After measuring the total mass of this test piece, it was placed in a constant temperature and humidity chamber at 40°C and 90% RH, and the change in mass was measured at regular intervals, and the moisture permeability was calculated according to the following formula. Moisture permeability (g / m 2 (day) = W × 240000 / S In the formula, S is the moisture permeability area (cm²). 2 ) where W represents the mass increase per hour (g / hr). The following criteria were used to evaluate moisture permeability. A...5000g / m 2 • days or more B···4000g / m 2 ·day or more 5000g / m 2 Less than a day C···3000g / m 2 ·day or more 4000g / m 2 Less than a day D···3000g / m 2Less than a day The "Moisture Permeability" column in Table 3 shows the calculated moisture permeability and the results of the moisture permeability evaluation.

[0120] <Adhesion to phenolic resin> In accordance with the test method described in "10 Adhesion Strength" of the Test Methods for Adhesive Tapes and Sheets in JIS Z 0237:2009, a 15 mm wide test piece was attached to a bakelite panel (phenol resin board, manufactured by Sumitomo Bakelite Co., Ltd., PL-1102) in a 25°C atmosphere, and pressed down once back and forth with a 2 kg rubber roll at a speed of 300 mm / min. After standing for 20 minutes, the peeling force was measured at a peeling angle of 90 degrees or 180 degrees and a peeling speed of 300 mm / min. The adhesive strength to phenolic resin was evaluated according to the following evaluation criteria. A...3.0N / 15mm or more B···2.5N / 15mm or more, 3.0N / less than 15mm C···2.0N / 15mm or more, 2.5N / less than 15mm D···2.0N / less than 15mm The "Adhesion to Phenolic Resin" column in Table 3 shows the measured adhesion to phenolic resin and the evaluation results of the adhesion to phenolic resin.

[0121] <Adhesion to human skin> Instead of a bakelite panel, the back of a human hand was used, and the adhesion strength was measured in the same manner as for phenolic resin. The back of the human hand was degreased with isopropyl alcohol and then air-dried before use. The adhesive strength to human skin was evaluated according to the following criteria. A···0.2~1.0N / 15mm D···Less than 0.2N / 15mm, or greater than 1.0N / 15mm Table 3, in the "Skin Adhesion" column, shows the measured adhesion strength to human skin and the evaluation results of that adhesion strength to human skin.

[0122] <Difference in adhesive strength between phenolic resin and human skin> The difference between the adhesive strength to phenolic resin and the adhesive strength to human skin was calculated using the following formula. "The difference between the adhesive strength to phenolic resin and the adhesive strength to human skin" = "Adhesion strength to phenolic resin" - "Adhesion strength to human skin" The difference in adhesive strength to phenol and to human skin was evaluated according to the following criteria. A...2.5N / 15mm or more B···2.0N / 15mm or more, 2.5N / less than 15mm C···1.5N / 15mm or more, 2.0N / less than 15mm D···1.5N / less than 15mm The "Difference in Adhesion" column in Table 3 shows the calculated difference in adhesion between the phenolic resin and human skin, as well as the evaluation results of the difference in adhesion between phenol and human skin.

[0123] <Storage modulus> 100 parts by mass of the manufactured urethane prepolymer and a curing agent (Coronate L (Tosoh Corporation product name) or Duranate E402-80B (Asahi Kasei Corporation product name)) were used in the amounts listed in Table 3 to uniformly mix, degass, and then applied to a release-treated polyester film (release body, thickness 50 μm) using a knife coater to a dry film thickness of 25 μm. The mixture was then cured and dried at 100°C for 3 minutes to form an adhesive layer on the release body. After attaching the release body to the resulting adhesive layer, it was stored in a hot air dryer at 50°C for 3 days to complete the crosslinking reaction of the adhesive layer. The release body was peeled off and rolled into a cylindrical shape with a width of 4 cm × length of 30 cm, with a diameter of approximately 3 mm and a length of 4 cm, to be used as a test sample. The storage modulus E' is the value obtained by measuring the storage modulus E'(Pa) of the obtained test sample under the following measurement conditions with a strain of 1%. The storage modulus at 25°C and 80°C is shown in Table 3. Measurement device: Dynamic viscoelasticity measuring device (EXSTAR 6000 DMS 6100, Seiko Instruments product name) Mode: Tensile mode Temperature range: -80 to 130°C Heating rate: 3°C / min Measurement frequency: 1Hz

[0124] [Explanation of Results] In Table 3, Examples 2 to 5 correspond to embodiments of the present invention, and Example 1 corresponds to a comparative example of the present invention. If the moisture permeability rating is A, B, or C, the adhesive has excellent moisture permeability. If the adhesion strength to phenolic resin is rated A, B, or C, the adhesion strength to skin is rated A, and the difference in adhesion strength is rated A, B, or C, then it is possible to achieve both low adhesion to skin and high adhesion to the substrate. Therefore, the adhesives in Examples 2-5 exhibit excellent moisture permeability while simultaneously achieving low adhesion to the skin and high adhesion to the substrate. In contrast, the adhesive in Example 1 had low moisture permeability and low adhesion to the skin. This is thought to be due to its low EO unit content and low polarity. [Industrial applicability]

[0125] The adhesive using the urethane prepolymer of the present invention has excellent moisture permeability, low tackiness to the skin, and high tackiness to the substrate, making it particularly suitable for use as an adhesive for attaching various wearable devices. Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2019-036306, filed on February 28, 2019, are incorporated herein by reference as the disclosure of the specification of this invention.

Claims

1. A hydroxyl-terminated urethane prepolymer obtained by reacting an oxyalkylene polymer A having an average of 2.1 to 3 hydroxyl groups per molecule, an oxyalkylene polymer B having 1 hydroxyl group per molecule, and a diisocyanate compound, The oxyalkylene polymer A comprises oxyalkylene polymer a having 3 hydroxyl groups per molecule and oxyalkylene polymer b having 2 hydroxyl groups per molecule. The total content of oxyalkylene polymer a and oxyalkylene polymer b relative to the total mass of oxyalkylene polymer A is 80% by mass or more. The number-average molecular weight of the oxyalkylene polymer a is 8,000 to 25,000. The number-average molecular weight of the oxyalkylene polymer b is 8,000 to 25,000. The number average molecular weight of the oxyalkylene polymer B is 5000 or more. A hydroxyl-terminated urethane prepolymer in which the ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer is greater than 10% by mass, and the content ratio of the oxyalkylene polymer A to the total mass of the oxyalkylene polymer A and the oxyalkylene polymer B is 20 to 80% by mass.

2. The hydroxyl-terminated urethane prepolymer according to claim 1, wherein the number average molecular weight of the oxyalkylene polymer B is greater than 5000.

3. The hydroxyl-terminated urethane prepolymer according to claim 1 or 2, wherein the ethylene oxide unit content of the oxyalkylene polymer a is 15% by mass or more.

4. A hydroxyl-terminated urethane prepolymer according to any one of claims 1 to 3, wherein the average number of hydroxyl groups is less than 3.

0.

5. The hydroxyl-terminated urethane prepolymer according to any one of claims 1 to 4, wherein the ethylene oxide unit content in the hydroxyl-terminated urethane prepolymer is 12 to 50% by mass.

6. An adhesive obtained by reacting a hydroxyl-terminated urethane prepolymer according to any one of claims 1 to 5 with a curing agent containing a polyisocyanate compound having three or more isocyanate groups in one molecule, An adhesive having an ethylene oxide unit content of 10% by mass or more.

7. The storage modulus at 80°C is 4.0 × 10⁻⁶. ５ The adhesive according to claim 6, wherein the pressure is Pa or less.

8. Moisture permeability of 3000 g / m ２ - The adhesive according to claim 6 or 7, wherein the adhesive is for days or longer.

9. An adhesive according to any one of claims 6 to 8, wherein the adhesive strength to human skin is 0.2 to 1 N / 15 mm.

10. An adhesive according to any one of claims 6 to 9, wherein the difference between the adhesive strength to phenolic resin and the adhesive strength to human skin is 2 N / 15 mm or more.

11. Substrate and An adhesive material having an adhesive layer provided on the surface of the substrate, the adhesive layer containing the adhesive described in any one of claims 6 to 10.

12. Substrate and An adhesive tape having an adhesive layer provided on at least one surface of the substrate, the adhesive layer containing the adhesive according to any one of claims 6 to 10.

13. The wearable device itself, A wearable device having an adhesive layer containing the adhesive described in any one of claims 6 to 10, provided on at least a portion of the surface to be adhered to the wearable device body.

14. The wearable device itself, A wearable device kit comprising an adhesive according to any one of claims 6 to 10, an adhesive material according to claim 11, or an adhesive tape according to claim 12, for attaching the wearable device body to the skin.

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