Paste circuit and wearable device

Abstract

Provided is a paste circuit having a circuit pattern and an adhesive agent layer, which does not undergo disadvantages such as the short-circuiting of a circuit and corrosion and shows an excellent durability of appropriate adhesion force. The paste circuit according to the present invention has a circuit pattern and an adhesive agent layer, in which an adhesive agent constituting the adhesive agent layer comprises a reaction product of a hydroxyl-group-terminal urethane prepolymer and a curing agent, the hydroxyl-group-terminal urethane prepolymer is a reaction product of an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3.0, an oxyalkylene polymer B having one hydroxyl group per molecule and a diisocyanate compound and contains an ethyleneoxide unit at a content of 5% by mass or more, and the curing agent comprises a polyisocyanate compound.

Description

Adhesive circuits and wearable devices

[0001] The present invention relates to an adhesive circuit having a circuit pattern and an adhesive layer, and a wearable device including the adhesive circuit.

[0002] In flexible electronics, a technique for bonding a circuit to a flexible substrate is used. For example, Patent Document 1 describes a circuit board member in which a flexible film on which a circuit pattern is formed is laminated with an adhesive layer made of an adhesive containing an acrylic polymer (acrylic adhesive). It has also been proposed to use a silicone adhesive for the adhesive layer (see, for example, Patent Document 2).

[0003] JP 2004-346106 A JP 2006-281488 A

[0004] Acrylic adhesives have had problems with circuit shorts and corrosion due to adhesive components such as monomers remaining after polymerization. Furthermore, for example, when an adhesive layer is formed on a moisture-permeable or breathable support, discoloration can occur at the contact surface between the circuit and the support. Silicone adhesives also have had problems with circuit defects similar to those caused by acrylic adhesives due to the volatilization of low-molecular-weight siloxanes.

[0005] The present invention is intended to solve the above-mentioned problems, and aims to provide a circuit having a circuit pattern and an adhesive layer, which does not cause problems such as circuit shorts or corrosion, and has excellent durability of moderate adhesive strength.

[0006] The present invention is based on the discovery that by forming the adhesive layer of a circuit patch from a specified polyurethane-based adhesive, problems such as circuit short circuits and corrosion do not occur and the adhesive strength is maintained at a suitable level.

[0007] The present invention provides the following means. [1] A patch circuit having a circuit pattern and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer comprises a reaction product of a hydroxyl-terminated urethane prepolymer and a curing agent, the hydroxyl-terminated urethane prepolymer being a reaction product of an oxyalkylene polymer A having an average number of 2.1 to 3.0 hydroxyl groups per molecule, an oxyalkylene polymer B having one hydroxyl group per molecule, and a diisocyanate compound, the hydroxyl-terminated urethane prepolymer having an ethylene oxide unit content of 5% by mass or more, and the curing agent comprising a polyisocyanate compound. [2] The patch circuit according to [1], wherein the oxyalkylene polymer B has a number-average molecular weight of 3,500 or more. [3] The patch circuit according to [1] or [2], wherein, out of a total of 100 parts by mass of the oxyalkylene polymer A, 20 parts by mass or more of the oxyalkylene polymer A1 has 3 hydroxyl groups per molecule. [4] The adhesive circuit according to any one of [1] to [3], wherein the oxyalkylene polymer A has an ethylene oxide unit content of 10% by mass or more. [5] The adhesive circuit according to any one of [1] to [4], wherein the blending amount of polymer A is 10 to 95 parts by mass relative to 100 parts by mass of the total of polymer A and polymer B. [6] The adhesive circuit according to any one of [1] to [5], wherein the polyisocyanate compound has three or more isocyanate groups in one molecule. [7] The adhesive circuit according to any one of [1] to [6], wherein the thickness of the pressure-sensitive adhesive layer is 5 to 100 μm. The adhesive circuit according to any one of [1] to [6]. [8] The moisture permeability of the pressure-sensitive adhesive layer is 3000 g / (m ２ [9] The adhesive circuit according to any one of [1] to [7], wherein the adhesive layer is formed on a main surface of a sheet-like support.

[10] The adhesive circuit according to [9], wherein the adhesive layer is formed on one main surface of the support, and the circuit pattern is formed on the other main surface of the support.

[11] The adhesive circuit according to any one of [1] to

[10] , wherein the circuit pattern is formed of conductive ink.

[12] A wearable device comprising the adhesive circuit according to any one of [1] to

[11] .

[0008] According to the present invention, a patch circuit having a circuit pattern and an adhesive layer can be provided that is free from defects such as circuit shorts and corrosion and has an appropriate level of adhesive strength that is excellent in durability. The patch circuit of the present invention is suitable for flexible devices, and since the adhesive layer can exert good fixation of circuits and the like with low load on the skin, it can be suitably applied to wearable devices.

[0009] 1 is a schematic cross-sectional view of a paste circuit according to a first embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of a paste circuit according to a second embodiment of the present invention; FIG. 3 is a schematic cross-sectional view of a paste circuit according to a third embodiment of the present invention; FIG. 4 is a schematic cross-sectional view of a paste circuit according to a fourth embodiment of the present invention; FIG. 5 is a schematic cross-sectional view of a paste circuit according to a fifth embodiment of the present invention; and FIG. 6 is a schematic cross-sectional view of a paste circuit according to a sixth embodiment of the present invention.

[0010] The definitions and meanings of terms and notations used in this specification are shown below. The number average molecular weight (Mn) and weight average molecular weight (Mw) are polystyrene-equivalent molecular weights determined by gel permeation chromatography (GPC) based on a calibration curve prepared using a standard polystyrene sample. The hydroxyl value-equivalent molecular weight is a value calculated from the formula 56100 × (number of hydroxyl groups per molecule) / (hydroxyl value [mg KOH / g]). The hydroxyl value is determined by measurement in accordance with JIS K 1557:2007-1. The degree of unsaturation is determined by measurement in accordance with JIS K 1557-3:2007. The isocyanate index is the equivalent ratio ([isocyanate group] / [active hydrogen-containing group]) of the isocyanate group to be reacted and the active hydrogen-containing group (e.g., hydroxyl group), and is expressed as a percentage. The moisture permeability is determined by measurement in accordance with JIS Z 0208:1976 (cup method). Specifically, it is measured by the method described in the examples.

[0011] The adhesive circuit of the present invention is an adhesive circuit having a circuit pattern and a pressure-sensitive adhesive layer, wherein the adhesive constituting the pressure-sensitive adhesive layer comprises a reaction product of a predetermined hydroxyl-terminated urethane prepolymer and a curing agent. The hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer A (hereinafter also referred to simply as "polymer A") having an average number of hydroxyl groups per molecule of 2.1 to 3.0, an oxyalkylene polymer B (hereinafter also referred to simply as "polymer B") having one hydroxyl group per molecule, and a polyisocyanate compound, and the hydroxyl-terminated urethane prepolymer has an ethylene oxide (EO) unit content of 5% by mass or more. The curing agent also contains a polyisocyanate compound. By forming the pressure-sensitive adhesive layer using the predetermined polyurethane-based adhesive, a pressure-sensitive adhesive circuit can be constructed that is free from defects such as circuit shorts and corrosion and has a moderate level of adhesive strength and durability.

[0012] [Adhesive Layer] The adhesive layer is formed from an adhesive containing a reaction product of a specific hydroxyl-terminated urethane prepolymer and a curing agent. Polyurethane-based adhesives formed from such urethane prepolymers are suitable for adhesive circuits in terms of circuit formation and adhesive strength. The adhesive layer is formed by coating or adhering to a support, a circuit pattern, a circuit pattern substrate, or the like, which is a component of the adhesive sheet in the embodiment of the adhesive circuit described below.

[0013] (Hydroxyl Group-Terminated Urethane Prepolymer) The hydroxyl group-terminated urethane prepolymer of the present invention is a reaction product of polymer A, polymer B, and a diisocyanate compound. In this reaction product, hydroxyl groups in polymer A and polymer B react with isocyanate groups of the diisocyanate compound to form urethane bonds, and the unreacted hydroxyl groups correspond to the terminal hydroxyl groups of the hydroxyl group-terminated urethane prepolymer.

[0014] The hydroxyl-terminated urethane prepolymer has an EO unit content of 5% by mass or more, preferably 10 to 80% by mass, and more preferably 12 to 50% by mass. When the EO unit content in the hydroxyl-terminated urethane prepolymer is within the above range, it is easy to obtain a pressure-sensitive adhesive layer that is low in load on the skin and exhibits good fixation of circuits and the like and has good adhesive strength. The EO units in the hydroxyl-terminated urethane prepolymer are derived from the EO units constituting polymer A and the EO units constituting polymer B, １３ The content can be determined by analyzing the monomer composition of the oxyalkylene chain in the hydroxyl-terminated urethane prepolymer by C-NMR (nuclear magnetic resonance) measurement.

[0015] The EO unit content in the pressure-sensitive adhesive layer is also determined by the following formula: １３ The content is preferably 5% by mass or more, more preferably 10 to 80% by mass, and even more preferably 12 to 50% by mass, from the viewpoints of having good moisture permeability, low load on the skin, and good fixation of circuits and the like, as determined by C-NMR measurement.

[0016] <Oxyalkylene Polymer A> The average number of hydroxyl groups per molecule of oxyalkylene polymer A is 2.1 to 3.0, preferably 2.2 to 2.9, and more preferably 2.3 to 2.8. When the average number of hydroxyl groups of polymer A is within the above range, it is easy to obtain a pressure-sensitive adhesive layer that has good moisture permeability, is less likely to leave adhesive residue, is low in stress on the skin, and exhibits good fixation of circuits, etc. and has good adhesive strength. The average number of hydroxyl groups per molecule of polymer A can be calculated from the measured values ​​of the hydroxyl value and Mn of polymer A by the formula: hydroxyl value × Mn / 56100.

[0017] Polymer A may be one type of oxyalkylene polymer, or two or more types of oxyalkylene polymers. When polymer A is composed of two or more types of oxyalkylene polymers, it is easy to adjust the adhesive strength of the pressure-sensitive adhesive layer. Polymer A may be composed of, for example, an oxyalkylene polymer A1 (hereinafter simply referred to as "polymer A1") having three hydroxyl groups per molecule, and an oxyalkylene polymer A2 (hereinafter simply referred to as "polymer A2") having two hydroxyl groups per molecule. Polymer A may also be composed of an oxyalkylene polymer having four or more hydroxyl groups per molecule, as long as the average number of hydroxyl groups per molecule is 2.1 to 3.0. When polymer A is composed of polymer A1 and polymer A2, the weighted average of the number of hydroxyl groups per molecule of polymer A1 and the number of hydroxyl groups per molecule of polymer A2, based on the compositional ratio (blending amount) of polymer A1 and polymer A2, can be considered to be the average number of hydroxyl groups of polymer A.

[0018] Of the total 100 parts by mass of polymer A, from the viewpoints of good adhesive strength of the pressure-sensitive adhesive layer, less adhesive residue, etc., it is preferable that polymer A1 account for 20 parts by mass or more, more preferably 25 to 95 parts by mass, and even more preferably 30 to 90 parts by mass.

[0019] From the viewpoints of good flexibility and adhesive strength of the pressure-sensitive adhesive layer, and resistance to adhesive residue, the Mn of polymer A is preferably 1,000 to 50,000, more preferably 5,000 to 30,000, and even more preferably 8,000 to 25,000. The Mw / Mn of polymer A is preferably less than 1.20, more preferably less than 1.13, and even more preferably less than 1.10, because the closer to 1 and the narrower the molecular weight distribution, the less likely the hydroxyl-terminated urethane prepolymer will become highly viscous and the more efficient the synthesis. Furthermore, from the viewpoints of good curing properties of the hydroxyl-terminated urethane prepolymer and resistance to adhesive residue in the pressure-sensitive adhesive layer, the unsaturation degree of polymer A is preferably 0.020 meq / g or less, more preferably 0.018 meq / g or less, and even more preferably 0.015 meq / g or less, with the degree of unsaturation being closer to 0 meq / g being preferable. When polymer A is composed of two or more kinds of oxyalkylene polymers, it is preferable that each of the oxyalkylene polymers has Mn, Mw / Mn and degree of unsaturation within the above ranges.

[0020] The synthesis method of polymer A is not particularly limited, but can be obtained, for example, by ring-opening addition polymerization of a compound having a cyclic ether structure, preferably an alkylene oxide, with an initiator having two or more active hydrogens in the presence of a catalyst. When polymer A consists of polymer A1 and polymer A2, a method can also be used in which an initiator having three active hydrogens and an initiator having two active hydrogens are used in combination to perform ring-opening addition polymerization of a compound having a cyclic ether structure, thereby simultaneously producing polymer A1 and polymer A2. From the viewpoint of more accurately adjusting the blending amounts of polymer A1 and polymer A2, a method in which polymer A obtained by ring-opening addition polymerization of a compound having a cyclic ether structure with an initiator having three active hydrogens and polymer B obtained by ring-opening addition polymerization of a compound having a cyclic ether structure with an initiator having two active hydrogens are separately synthesized and then mixed is preferred.

[0021] The compound having a cyclic ether structure is preferably linear or branched and has 2 to 14 carbon atoms, more preferably 2 to 10 carbon atoms, and even more preferably 2 to 4 carbon atoms. The compound having a cyclic ether structure may be one type alone or two or more types. Examples of compounds having a cyclic ether structure include ethylene oxide (EO), propylene oxide (PO), 1,2-butylene oxide, 2,3-butylene oxide, methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, lauryl glycidyl ether, hexyl glycidyl ether, and tetrahydrofuran. Of these, EO and PO are preferred.

[0022] When two or more compounds having a cyclic ether structure are used in combination, the arrangement of oxyalkylene groups derived from each compound may be random or block in the polymer A. The polymer A has appropriate hydrophilicity in consideration of good adhesive strength to the skin, and from the viewpoint of obtaining a pressure-sensitive adhesive layer with suppressed crystallinity, it preferably contains EO units (oxyethylene groups), more preferably 10% by mass or more, even more preferably 15 to 60% by mass, and still more preferably 20 to 50% by mass.

[0023] The content of EO units in polymer A is １３ The monomer composition of the oxyalkylene chain in polymer A can be analyzed and determined by C-NMR measurement. For example, when the oxyalkylene chain in polymer A is composed of EO units and PO units, the EO unit content can be calculated based on the area of ​​the peak representing the methylene group of the EO unit and the area of ​​the peak representing the methyl group of the PO unit. When polymer A is composed of polymer A1 and polymer A2, the EO unit contents of polymer A1 and polymer A2 are similar. The EO unit content in polymer A can be considered to be a value calculated from the amount of ethylene oxide blended in the synthetic raw materials for polymer A. When polymer A is composed of polymer A1 and polymer A2, the EO unit content of polymer A can be considered to be the weighted average of the EO unit content of polymer A1 and the EO unit content of polymer A2 based on the compositional proportions (blending amounts) of polymer A1 and polymer A2.

[0024] Examples of groups having active hydrogen in the initiator include a hydroxyl group, a carboxyl group, and an amino group having a hydrogen atom bonded to a nitrogen atom. Of these, a hydroxyl group is preferred, and an alcoholic hydroxyl group is more preferred. Examples of initiators having three hydroxyl groups include glycerin, trimethylolethane, trimethylolpropane, and 1,2,6-hexanetriol. Of these, one type may be used alone, or two or more types may be used in combination. Examples of initiators having two hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol. Of these, one type may be used alone, or two or more types may be used in combination.

[0025] The number of active hydrogens in the initiator usually corresponds to the number of hydroxyl groups per molecule of the oxyalkylene polymer. Polymer A1 can be synthesized, for example, using glycerin as an initiator. Polymer A2 can be synthesized, for example, using propylene glycol as an initiator. The initiators used as raw materials for synthesizing the oxyalkylene polymer are: １３ When polymer A is composed of polymer A1 and polymer A2, the type and amount of polymer A can be identified by C-NMR measurement. １３ The ratio of polymer A1 to polymer A2 is determined by determining the content of oxyalkylene groups such as EO units and PO units bound to each initiator from information on the type and amount of the initiator obtained by C-NMR measurement.

[0026] Ring-opening addition polymerization can be carried out using known catalysts, such as alkali catalysts such as potassium hydroxide, transition metal compound-porphyrin complex catalysts such as complexes obtained by reacting an organoaluminum compound with porphyrin, composite metal cyanide complex catalysts, and catalysts made of phosphazene compounds. Among these catalysts, composite metal cyanide complex (DMC) catalysts are preferred because they tend to produce oxyalkylene polymers with narrow molecular weight distributions and relatively low viscosity. Known compounds can be used as composite metal cyanide complexes, such as zinc hexacyanocobaltate complexes with tert-butanol as a ligand. Synthesis of oxyalkylene polymers by ring-opening addition polymerization using a DMC catalyst can be carried out by known methods, for example, production methods described in WO 2003 / 062301, WO 2004 / 067633, JP 2004-269776 A, JP 2005-15786 A, WO 2013 / 065802, JP 2015-10162 A, etc. can be applied.

[0027] <Oxyalkylene Polymer B> The oxyalkylene polymer B has one hydroxyl group per molecule. The polymer B may be one type of oxyalkylene polymer or two or more types of oxyalkylene polymers. The number of hydroxyl groups of the polymer B is, like the polymer A, １３ This can be confirmed by identifying the type and amount of the initiator used in the synthesis by C-NMR measurement.

[0028] From the viewpoints of good flexibility of the pressure-sensitive adhesive layer and good conformability when applied to the skin, the Mn of polymer B is preferably 3,500 or more, more preferably 4,000 to 50,000, and even more preferably 4,500 to 30,000. The Mw / Mn of polymer B is preferably less than 1.20, more preferably less than 1.13, and even more preferably less than 1.10, because the closer to 1 and the narrower the molecular weight distribution, the less likely the hydroxyl-terminated urethane prepolymer is to become highly viscous and the more efficient the synthesis. Furthermore, from the viewpoints of good curing properties of the hydroxyl-terminated urethane prepolymer and less likely to leave adhesive residue in the pressure-sensitive adhesive layer, the degree of unsaturation of polymer B is preferably 0.015 meq / g or less, more preferably 0.013 meq / g or less, and even more preferably 0.010 meq / g or less, with the degree of unsaturation being closer to 0 meq / g being preferable. When polymer B is composed of two or more kinds of oxyalkylene polymers, it is preferable that each of the oxyalkylene polymers has Mn, Mw / Mn and degree of unsaturation within the above ranges.

[0029] The synthesis method of polymer B is not particularly limited, but it can be obtained, for example, by ring-opening addition polymerization of a compound having a cyclic ether structure, preferably an alkylene oxide, to an initiator having one active hydrogen in the presence of a catalyst. The compound having a cyclic ether structure is the same as that described for polymer A. Preferably, PO is used alone, or EO and PO are used in combination.

[0030] Polymer B has an appropriate moisture permeability taking into consideration good adhesive strength to the skin, and from the viewpoint of obtaining a pressure-sensitive adhesive layer with suppressed crystallinity, the EO unit content is preferably 0 to 80 mass%, more preferably 0 to 60 mass%, and even more preferably 0 to 50 mass%. The EO unit content in Polymer B is determined in the same manner as for Polymer A.

[0031] Examples of the group having an active hydrogen in the initiator include the same as those in the case of polymer A, with a hydroxyl group being preferred and an alcoholic hydroxyl group being more preferred. As the initiator having one hydroxyl group, from the viewpoint of availability and the like, a monohydric alcohol having 2 to 4 carbon atoms is preferred, for example, n-propanol, isopanol, n-butanol, sec-butanol, isobutanol, tert-butanol, etc., and among these, n-butanol, sec-butanol, isobutanol, and tert-butanol are preferred. The initiator may be used alone or in combination of two or more types. The ring-opening addition polymerization can be carried out by a known method, as in the case of polymer A.

[0032] <Diisocyanate Compound> The diisocyanate compound used in the synthesis of the hydroxyl group-terminated urethane prepolymer is an organic compound having two isocyanate groups per molecule. The diisocyanate compound may be used alone or in combination of two or more types.

[0033] The diisocyanate compound may be an aliphatic diisocyanate compound, which may be either linear or branched, and examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, etc. Furthermore, examples of alicyclic diisocyanate compounds include isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (HMDI), 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, etc. Examples of aromatic diisocyanate compounds include tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, dialkyldiphenylmethane diisocyanate, and tetraalkyldiphenylmethane diisocyanate. Examples of aromatic aliphatic diisocyanate compounds include xylylene diisocyanate and tetramethylxylylene diisocyanate (TMXDI). Of these, from the viewpoint of obtaining a pressure-sensitive adhesive layer having a high glass transition temperature, good tensile strength, and elongation at break, HDI, IPDI, HMDI, and TMXDI are preferred, and HDI is more preferred.

[0034] Furthermore, as the diisocyanate compound, a bifunctional isocyanate-terminated urethane prepolymer obtained by previously reacting the above-mentioned diisocyanate compound with a diol (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, etc.) can also be used.

[0035] <Synthesis Method> The hydroxyl-terminated urethane prepolymer can be synthesized, for example, by a method in which polymer A, polymer B, a diisocyanate compound, and a catalyst and solvent, which are added as appropriate as necessary, are all charged into a reaction vessel at once, or by a method in which the diisocyanate compound is subsequently added dropwise or the like to a reaction vessel into which polymer A, polymer B, and a catalyst and solvent, which are added as appropriate as necessary, have been charged. From the viewpoint of ease of control of the molecular weight distribution of the hydroxyl-terminated urethane prepolymer due to preferential reaction of low-molecular-weight components in the synthesis raw materials, the method of adding a diisocyanate compound is preferred.

[0036] As the catalyst, known urethane catalysts such as tertiary amine compounds and organometallic compounds are used. The catalysts may be used alone or in combination of two or more. Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU). Examples of organometallic compounds include 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 the catalyst include tin compounds such as dibutyltitanium dichloride, tetrabutyltitanium, 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. When a catalyst is used, the amount used is preferably 0.001 to 1.0 part by mass, more preferably 0.002 to 0.5 part by mass, and even more preferably 0.005 to 0.1 part by mass relative to 100 parts by mass of the total of Polymer A and Polymer B, from the viewpoint of promoting an appropriate urethanization reaction.

[0037] Examples of the solvent include ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; and aromatic hydrocarbons such as toluene and xylene. The solvent may be used alone or in combination of two or more. When a solvent is used, the amount thereof is preferably 50 to 500 parts by mass, more preferably 70 to 400 parts by mass, and even more preferably 80 to 300 parts by mass per 100 parts by mass of the total of Polymer A and Polymer B, from the viewpoints of uniformity of the reaction system and synthesis efficiency.

[0038] The blending amount of polymer A relative to 100 parts by mass of the total of polymer A and polymer B is preferably 10 to 95 parts by mass, more preferably 20 to 90 parts by mass, and even more preferably 30 to 85 parts by mass, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate moisture permeability while taking into consideration good adhesive strength to the skin.

[0039] Furthermore, from the viewpoint of efficiently obtaining a hydroxyl group-terminated urethane prepolymer having an appropriate molecular chain length, it is preferable to react Polymer A, Polymer B, and a diisocyanate compound at an isocyanate index of less than 100, preferably 30 to 95, and more preferably 50 to 95.

[0040] From the viewpoint of promoting the urethanization reaction and suppressing side reactions, the reaction temperature is preferably less than 100° C., more preferably 70 to 95° C., and even more preferably 75 to 90° C. After completion of the reaction, a reaction terminator such as acetylacetone may be added to deactivate the catalyst.

[0041] The average number of hydroxyl groups per molecule of the hydroxyl-terminated urethane prepolymer is preferably less than 3.0, more preferably 1.7 to 2.9, and even more preferably 1.8 to 2.5, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate moisture permeability while taking into account good adhesive strength to the skin. The average number of hydroxyl groups per molecule of the hydroxyl-terminated urethane prepolymer is regarded as a weighted average value of the average number of hydroxyl groups per molecule of polymer A and the number of hydroxyl groups per molecule of polymer B, which is 1, based on the compositional proportions (blending amounts) of polymer A and polymer B.

[0042] (Curing Agent) The adhesive constituting the adhesive layer is obtained by reacting a hydroxyl group-terminated urethane prepolymer with a curing agent. The curing agent includes a polyisocyanate compound having two or more isocyanate groups per molecule. The polyisocyanate compound may be used alone or in combination of two or more. As the polyisocyanate compound, a diisocyanate compound is preferred from the viewpoints of availability and reactivity. Furthermore, a polyisocyanate compound having three or more isocyanate groups per molecule is preferred from the viewpoints of good adhesive strength of the adhesive layer and less adhesive residue.

[0043] Specific examples of diisocyanate compounds include those similar to the specific examples of diisocyanate compounds constituting the hydroxyl group-terminated urethane prepolymer described above. Examples of polyisocyanate compounds include derivatives of the above-mentioned diisocyanate compounds, such as isocyanurate-modified compounds (e.g., "Coronate (registered trademark; hereinafter, omitted) HX" (manufactured by Tosoh Corporation)), biuret-modified compounds (e.g., "Duranate (registered trademark) 24A-100" (manufactured by Asahi Kasei Corporation)), allophanate-modified compounds, and trifunctional or higher isocyanate-terminated urethane prepolymers (adducts) which are reaction products of diisocyanate compounds and polyols having three or more hydroxyl groups per molecule (e.g., trimethylolpropane) (e.g., "Coronate L", "Coronate L-55E", "Coronate L-45E" (all manufactured by Tosoh Corporation)).

[0044] The isocyanate index of the polyisocyanate compound to be reacted with the hydroxyl group-terminated urethane prepolymer is preferably greater than 100, more preferably from 101 to 1,500, and even more preferably from 105 to 1,000.

[0045] (Adhesive) The adhesive used to form the adhesive layer may be a one-component type in which a hydroxyl group-terminated urethane prepolymer and a curing agent are premixed, or may be a two-component type consisting of a first component containing a hydroxyl group-terminated urethane prepolymer and a second component containing a curing agent.

[0046] In synthesizing the reaction product of the hydroxyl-terminated urethane prepolymer and the curing agent, a catalyst and a solvent may be used as needed. The urethanization catalyst described above can be used as the catalyst. When a catalyst is used, the amount used is preferably 0.001 to 1.0 part by mass, more preferably 0.002 to 0.5 parts by mass, and even more preferably 0.005 to 0.1 part by mass, per 100 parts by mass of the hydroxyl-terminated urethane prepolymer and the curing agent combined. After completion of the reaction, it is preferable to add a reaction terminator to inactivate the catalyst.

[0047] The solvent may be the same as that used in the synthesis of the hydroxyl-terminated urethane prepolymer described above. When a solvent is used, the amount used is preferably 50 to 500 parts by mass, more preferably 70 to 400 parts by mass, and even more preferably 80 to 300 parts by mass, per 100 parts by mass of the hydroxyl-terminated urethane prepolymer and curing agent combined.

[0048] The reaction temperature is preferably less than 120°C, more preferably 40 to 110°C, and even more preferably 50 to 100°C, from the viewpoint of promoting the urethanization reaction and suppressing side reactions.

[0049] (Other Components) The pressure-sensitive adhesive may contain other components in addition to the reaction product of the hydroxyl-terminated urethane prepolymer and the curing agent. Examples of other components include various additives such as plasticizers, antioxidants, antistatic agents, fillers, UV absorbers, light stabilizers, conductivity-imparting agents, and leveling agents. A solvent may also be contained. These other components in the pressure-sensitive adhesive may be used alone or in combination of two or more, and may be blended in an amount within a range that does not impair the effects of the present invention.

[0050] The plasticizer can be selected from the viewpoints of compatibility with other components and wettability of the pressure-sensitive adhesive layer to the adherend, and examples thereof include fatty acid esters having 8 to 30 carbon atoms, phosphate esters, etc. Antioxidants contribute to suppressing thermal degradation of the pressure-sensitive adhesive layer, and examples thereof include phenolic, amine, sulfur, and phosphorus-based antioxidants. Of these, phenolic antioxidants are preferred due to their low skin sensitization. Antistatic agents contribute to suppressing damage to circuit patterns caused by electrostatic discharge, and examples thereof include inorganic salts; ionic liquids containing imidazolium ions, pyridinium ions, ammonium ions, etc.; surfactants, etc. Fillers include talc, calcium carbonate, titanium oxide, etc. UV absorbers include benzophenone-based, benzotriazole-based, salicylic acid-based, oxalic acid anilide-based, cyanoacrylate-based, and triazine-based UV absorbers. Light stabilizers include hindered amine-based light stabilizers and UV stabilizers. Examples of the conductivity imparting agent include fine metal particles such as silver nanoparticles.

[0051] (Moisture Permeability) The moisture permeability of the adhesive layer is preferably 3000 g / (m) from the viewpoint of providing the adhesive layer with low load on the skin and good adhesive strength. ２ ·day) or more, more preferably 3500 g / (m ２ ·day) or more, more preferably 4000 (g / m ２ -day) or more. The upper limit of the moisture permeability is not particularly limited. The moisture permeability in the present invention is a value measured in an atmosphere of 40°C and 90% RH, and is a value when the adhesive layer is 25 μm thick. Specifically, it is measured by the method described in the Examples. In the Examples, the moisture permeability of the adhesive sheet including the support of the adhesive layer was also compared with that of commercially available adhesive sheets.

[0052] (Adhesive Strength) The adhesive strength of the adhesive layer to human skin is preferably 0.2 to 1.0 N / 15 mm, more preferably 0.3 to 0.7 N / 15 mm, so that the adhesive layer can be said to have low load on the skin and good adhesive strength. Furthermore, when the adhesive layer is adhered to a sealant for a circuit pattern, for example, if the adhesive strength to phenolic resin, a common sealant material, is greater than the adhesive strength to human skin, preferably 2.0 N / 15 mm or more, more preferably 3.0 N / 15 mm or more, the adhesive layer can be said to exhibit good fixation of the circuit, etc. Note that the adhesive strength referred to here is a value measured according to a method in accordance with JIS Z 0237:2009, specifically, measured according to the method described in the Examples.

[0053] (Storage Modulus) The pressure-sensitive adhesive layer preferably has a storage modulus at 25°C of 1.0 × 10 or less from the viewpoint of good adhesive strength of the pressure-sensitive adhesive layer, particularly to the skin, and less adhesive residue. ４ ~5.0 x 10 ５ Pa, more preferably 2.0 x 10 ４ ~4.0 x 10 ５ Pa, more preferably 3.0 × 10 ４ ~3.0 x 10 ５ From the same viewpoint, the storage modulus at 80°C is preferably 4.0 × 10 ５ Pa or less, more preferably 5.0 × 10２ ~3.0 x 10 ５ Pa, more preferably 1.0 × 10 ３ ~6.0 x 10 ４ The storage modulus referred to here is a value measured using a dynamic viscoelasticity measuring device (measurement conditions: tension mode, strain 1%, temperature range -80 to 130°C, heating rate 3°C / min, frequency 1 Hz, sample: diameter 3 mm x length 4 cm).

[0054] [Circuit Pattern] The circuit pattern is formed from a conductive material and can be formed by a known method for forming a circuit pattern on a substrate or the like. For example, it can be formed by a subtractive method in which a metal thin film is processed into a pattern shape by etching, a full-active method or semi-active method using resist formation and plating technology, or a method in which a conductive ink (e.g., silver paste, etc.) is used to print a pattern shape. Of these, from the viewpoints of circuit retention and ease of fine circuit formation when applying the pressure-sensitive adhesive of the present invention, it is preferable to form a circuit pattern by a method using a conductive ink.

[0055] The substrate used for forming the circuit pattern can be a known material, such as paper or glass cloth impregnated with a phenolic resin or an epoxy resin. For producing a flexible adhesive circuit, a film such as a polyimide or polyester film is preferably used.

[0056] [Structure of Adhesive Circuit] Examples of embodiments of the adhesive circuit of the present invention include, but are not limited to, structures shown in the schematic cross-sectional views of Figures 1 to 6. Hereinafter, a preferred embodiment in which the effects of the present invention are exhibited will be described in which the adherend is skin, but the adherend of the adhesive circuit of the present invention is not limited to skin and can be any solid body.

[0057] 1 uses an adhesive sheet having an adhesive layer 11 formed on the main surface of a sheet-like support 12. This adhesive sheet covers a packaged device 22, which has a circuit pattern 21 and an insulating layer 23 formed in advance on a substrate and sealed thereon, and the adhesive layer 11 is pressed against the skin 40 with the packaged device 22 and the adhesive layer 11 around it in contact with the skin 40, thereby allowing the adhesive circuit to be attached to the skin 40.

[0058] The support 12 used in the pressure-sensitive adhesive sheet is preferably made of a material that has good conformability to the shape of the packaging device 22 and the skin 40, and that provides sufficient breaking strength even in a thin layer, such as a resin film, cloth, or paper. The support 12 may be made of one material alone, or two or more materials may be used in combination, or may be a composite material formed by lamination or the like. Examples of materials for the resin film include polyurethane; polyamide; acrylic resin; polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer; and polyester. Of these, polyurethane and polyamide are preferred from the viewpoint of good moisture permeability. Examples of cloth include woven fabric, nonwoven fabric, knitted fabric, and net, and the material may be the resin of the resin film material described above, or natural fibers such as cotton, silk, and wool.

[0059] The thickness of the support 12 is not particularly limited, as long as it can ensure conformability to the shapes of the package device 22 and the skin 40 and has sufficient breaking strength, and is, for example, 10 to 500 μm. The thickness of the pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheet is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 20 to 50 μm, from the viewpoint of ensuring good adhesion to the skin and moisture permeability.

[0060] The surface of the adhesive layer 11 of the adhesive sheet is preferably covered with a release liner to protect the surface of the adhesive layer 11 before application to the skin 40. The release liner may be one that is used in known adhesive tapes for skin, etc. Examples include high-quality paper, glassine paper, or parchment paper coated with a release agent such as silicone resin or fluororesin on its surface, as well as resin anchor coated or polyethylene-laminated high-quality paper coated with a release agent such as silicone resin or fluororesin on its surface. The release liner is peeled off from the surface of the adhesive layer 11 as appropriate, and the adhesive sheet is used.

[0061] 2 uses an adhesive sheet similar to that of the first embodiment, with an adhesive layer 11 formed on one main surface of a support 12 and a circuit pattern 21 formed on the other main surface of the support 12 opposite the adhesive layer 11. In this embodiment, the support 12 also serves as a base for the circuit pattern 21, which is advantageous in terms of the thin film thickness and flexibility of the adhesive circuit, its ability to conform to the shape of the skin 40, etc.

[0062] To form the circuit pattern 21 directly on the surface of the support 12, among the above-mentioned methods for forming a circuit pattern, a method such as printing using a conductive ink (for example, silver paste) is more preferable.

[0063] 2, the circuit pattern 21 on the support 12 is covered with an insulating layer 23, but the insulating layer 23 may not be formed depending on the intended use of the attached circuit, etc. The method for forming the insulating layer 23 is not particularly limited, but examples thereof include coating with a solder resist.

[0064] 3, a patch circuit according to a third embodiment has a circuit pattern 21 formed on the surface of an adhesive layer 11. This embodiment does not use a support 12, and is therefore more advantageous than the first and second embodiments in terms of the thickness and flexibility of the patch circuit, its ability to conform to the shape of the skin 40, etc. Furthermore, if the adhesive layer 11 is conductive, the patch circuit of this embodiment can also be used with the circuit pattern 21 and the skin 40 in a conductive state.

[0065] To form the circuit pattern 21 directly on the surface of the adhesive layer 11, among the above-mentioned methods for forming a circuit pattern, a method such as printing using a conductive ink (for example, silver paste) is more preferable.

[0066] In this embodiment, the adhesive layer 11 is not formed on a support 12, and therefore, before the circuit pattern 21 is formed and the adhesive layer 11 is attached to the skin 40, it is preferable that both sides of the adhesive layer 11 are covered with the release liner described above in order to protect both sides. An adhesive layer 11 formed in this manner without using a support 12 is called an adhesive transfer sheet. The release liner is peeled off from the surface of the adhesive layer 11 as appropriate, and the adhesive transfer sheet is used.

[0067] 3, the circuit pattern 21 on the adhesive layer 11 is covered with an insulating layer 23, but the insulating layer 23 may not be formed depending on the intended use of the adhesive circuit, etc. The method for forming the insulating layer 23 is the same as in the second embodiment described above.

[0068] 4, a patch circuit according to a fourth embodiment of the present invention has a substrate 22 on which a circuit pattern 21 is formed, and the substrate 22 has a main surface opposite to the circuit pattern 21 adhered to the surface of the adhesive layer 11. Unlike the first embodiment, the patch circuit can be attached to the skin 40 by pressing the adhesive layer 11 against the skin 40 using the adhesive transfer sheet described above, without directly contacting the circuit board on which the circuit pattern 21 has been formed in advance on the substrate 22 with the skin 40.

[0069] 4, the circuit pattern 21 on the substrate 22 is covered with an insulating layer 23, but the insulating layer 23 may not be formed depending on the intended use of the adhesive circuit, etc. The method for forming the insulating layer 23 is the same as in the second embodiment described above.

[0070] 5, a circuit pattern 21 formed on a substrate 22 is adhered to the surface of an adhesive layer 11 on the side opposite to the substrate 22. If the adhesive layer 11 is conductive, the adhesive circuit of this embodiment can also be applied with the circuit pattern 21 and the skin 40 in a conductive state, as in the second embodiment.

[0071] In Fig. 5, the circuit pattern 21 (shown on the lower side in the drawing) on ​​the substrate 22 is covered with an insulating layer 23, but the insulating layer 23 may not be formed depending on the intended use of the adhesive circuit, etc. The method for forming the insulating layer 23 is the same as in the second embodiment described above. Furthermore, the insulating layer 23 is not limited to covering the entire circuit pattern 21, and may cover only a portion of it, as shown in Fig. 5. When the adhesive layer 11 is conductive, an adhesive circuit of this type can be applied in a state where a portion of the circuit pattern 21 is electrically conductive with the skin 40 via the adhesive layer 11.

[0072] 6 uses an adhesive sheet similar to that of the first embodiment, with an adhesive layer 11 formed on one main surface of a support 12, and a package device 22 similar to that of the first embodiment adhered to the other main surface of the support 12 opposite the adhesive layer 11 by another adhesive layer 31. Unlike the first embodiment, the adhesive circuit of this embodiment can be attached to the skin 40 with only the adhesive layer 11 in contact with the skin 40, without bringing the circuit pattern 21 sealed as the package device 22 into contact with the skin 40.

[0073] The other adhesive layer 31 is not particularly limited as long as it has sufficient adhesive strength to fix the package device 22 to the main surface of the support 12, and known adhesives, double-sided tapes, etc. can be applied, and it may also be the same as the adhesive layer 11.

[0074] [Wearable Device] By using the above-described adhesive circuit of the present invention, it is possible to provide a wearable device in which the adhesive layer imposes a low load on the skin, the adhesion can be maintained for a long period of time, such as several days, without causing any abnormalities to the skin, and the circuit and the like are well fixed.

[0075] Examples of wearable devices that are attached to the skin include biosensors and environmental sensors, and items detected by biosensors include, for example, cardiac potential, pulse wave, body temperature, acceleration, heart rate interval, pulse rate interval, respiratory rate, electrocardiogram, electromyogram, activity level, blood pressure, body temperature, and brain waves.

[0076] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples, and various modifications are possible within the scope of the gist of the present invention.

[0077] [Measurement Methods] The methods for measuring various physical properties in the following Synthesis Examples and Production Examples are as follows: (Hydroxyl Value) The hydroxyl value V was determined in accordance with Method B (automatic potentiometric titration) of JIS K 1557-1:2007.

[0078] (Hydroxyl value-equivalent molecular weight) Hydroxyl value-equivalent molecular weight M ＯＨＶ was calculated from the hydroxyl value OHV [mgKOH / g] obtained above using the following formula: ＯＨＶ = 56.1 × 1000 × x / OHV In the formula, 56.1 represents the molecular weight of potassium hydroxide, and x represents the number of hydroxyl groups per molecule of the oxyalkylene polymer, and the number of hydroxyl groups per molecule of the initiator used in the synthesis of the oxyalkylene polymer was considered to be x.

[0079] (Number average molecular weight (Mn) and weight average molecular weight (Mw)) Mn and Mw were measured by gel permeation chromatography (GPC) under the following measurement conditions (polystyrene equivalent), and the molecular weight distribution (Mw / Mn) was calculated from these values. [Measurement conditions] - Instrument used: "HLC-8320GPC", manufactured by Tosoh Corporation - Column used: "TSKgel (registered trademark) SuperMultiporeHZ-M", manufactured by Tosoh Corporation - Detector: Refractive index (RI) detector - Detection temperature: 40°C - Eluent: Tetrahydrofuran - Flow rate: 0.350 mL / min - Sample concentration: 0.5% by mass - Sample injection amount: 10 μL - Standard sample: Polystyrene

[0080] (Ethylene oxide (EO) unit content) The EO unit content of the oxyalkylene polymer was determined based on the amounts of PO and EO used in the synthesis, and the amount of EO charged was considered to be the EO unit content in the oxyalkylene polymer. The EO unit content of the hydroxyl group-terminated urethane prepolymer was determined as the weighted average of the EO unit contents in each of the raw material components.

[0081] (Degree of unsaturation) The degree of unsaturation was measured in accordance with JIS K 1557-3:2007.

[0082] (Average number of hydroxyl groups per molecule of oxyalkylene polymer A) The number of hydroxyl groups per molecule of each of the oxyalkylene polymers A1 and A2 used as the oxyalkylene polymer A (the number of hydroxyl groups per molecule of the initiator used in the synthesis) was weighted based on the blending amounts of the oxyalkylene polymers A1 and A2, and the weighted average was used as the average number of hydroxyl groups per molecule.

[0083] (Average Number of Hydroxyl Groups per Molecule of Hydroxyl-Terminated Urethane Prepolymer) The number of hydroxyl groups per molecule of each oxyalkylene polymer (oxyalkylene polymers A1, A2, and B) used in the synthesis of the hydroxyl-terminated urethane prepolymer was weighted based on the blending amount of each oxyalkylene polymer, and the weighted average was regarded as the average number of hydroxyl groups per molecule.

[0084] [Substances Used] Details of the various substances used in the synthesis examples below are shown below. TBA-DMC catalyst: zinc hexacyanocobaltate complex with tert-butanol as a ligand PO: propylene oxide EO: ethylene oxide Adsorbent: synthetic magnesium silicate, "Kyoward (registered trademark) 600S", manufactured by Kyowa Chemical Industry Co., Ltd. DBTDL: dibutyltin dilaurate, manufactured by Tokyo Chemical Industry Co., Ltd.; urethane catalyst HDI: hexamethylene diisocyanate, "Duranate (registered trademark) 50M-HDI", manufactured by Asahi Kasei Corporation Curing agent: trimethylolpropane-modified tolylene diisocyanate (TMP adduct of TDI), "Coronate L", manufactured by Tosoh Corporation; solid content approximately 75% by mass Silver paste: "TR70901", manufactured by Taiyo Ink Mfg. Co., Ltd.

[0085] [Synthesis of Oxyalkylene Polymer] (Synthesis Example 1-1) 1000 g of glycerin as an initiator and a TBA-DMC catalyst (metal concentration 46 ppm by mass) were placed in a pressure vessel, and the atmosphere in the vessel was replaced with nitrogen. The reaction solution was heated to 135°C while stirring, and 120 g of PO was added and reacted. After the temperature rise of the reaction solution stopped, it was cooled to 135°C, and while stirring the reaction solution, 3782.4 g of PO and 945.6 g of EO were added to the vessel. After confirming that the internal pressure had stopped changing, an adsorbent was added, and neutralization and catalyst removal were performed to obtain an oxyalkylene polymer A1.

[0086] Synthesis Example 1-2 Oxyalkylene polymer A2 was synthesized in the same manner as in Synthesis Example 1-1, except that the initiator in Synthesis Example 1-1 was changed from glycerin to propylene glycol.

[0087] Synthesis Example 1-3 Oxyalkylene polymer B1 was synthesized in the same manner as in Synthesis Example 1-1, except that the initiator in Synthesis Example 1-1 was changed from glycerin to n-butanol, and after cooling the reaction solution, 2364 g of PO was added instead of EO.

[0088] The aspects of each oxyalkylene polymer produced in the above synthesis examples are shown in Table 1 below.

[0089]

[0090] [Synthesis of Hydroxyl-Terminated Urethane Prepolymer] (Synthesis Example 2-1) In a reaction vessel equipped with a thermometer, a stirrer, and a condenser, 36 parts by mass of oxyalkylene polymer A1, 48 parts by mass of oxyalkylene polymer A2, 16 parts by mass of oxyalkylene polymer B1, and 50.6 parts by mass of toluene and 50.6 parts by mass of ethyl acetate were added, and 0.006 parts by mass of DBTDL was added. After mixing at 40 ° C., 1.69 parts by mass of HDI (isocyanate index 85) was added and the mixture was allowed to react at 80 ° C. The average number of hydroxyl groups per molecule of the blended oxyalkylene polymer A (oxyalkylene polymers A1 and A2) was 2.4. While appropriately diluting with ethyl acetate, the mixture was maintained at 80 ° C. and reacted for 7 hours to obtain a transparent hydroxyl-terminated urethane prepolymer (prepolymer U1; average number of hydroxyl groups 2.1, EO unit content 17% by mass) solution with a concentration of 50% by mass.

[0091] (Synthesis Example 2-2) A reaction vessel equipped with a thermometer, a stirrer, and a cooling tube was charged with 30 parts by mass of oxyalkylene polymer A1, 70 parts by mass of oxyalkylene polymer A2, and 50.6 parts by mass of toluene and 50.6 parts by mass of ethyl acetate, and 0.006 parts by mass of DBTDL was added. After mixing at 40 ° C., 1.69 parts by mass of HDI (isocyanate index 85) was added and the mixture was allowed to react at 80 ° C. The average number of hydroxyl groups per molecule of the blended oxyalkylene polymer A (oxyalkylene polymers A1 and A2) was 2.4. While appropriately diluting with ethyl acetate, the mixture was maintained at 80 ° C. and reacted for 7 hours to obtain a transparent hydroxyl-terminated urethane prepolymer (prepolymer U2; average number of hydroxyl groups 2.5, EO unit content 20% by mass) solution with a concentration of 50% by mass.

[0092] [Production of Pressure-Sensitive Adhesive Sheet for Evaluation] (Production Example 1) 100 parts by mass of prepolymer U1 solution (concentration 50% by mass) and 10 parts by mass of curing agent (isocyanate index 500) were mixed and degassed, and then coated (dry film thickness 25 μm) on a polyester film (thickness 50 μm) as a release liner using a knife coater, and dried for 3 minutes at 100° C. to form a pressure-sensitive adhesive layer. A polyester nonwoven fabric (thickness 70 μm) was attached to the pressure-sensitive adhesive layer as a support, and the layer was cured in a hot air dryer at 50° C. for 3 days to produce pressure-sensitive adhesive sheet S1.

[0093] (Production Example 2) A pressure-sensitive adhesive sheet S6 was produced in the same manner as in Production Example 1, except that the prepolymer U1 solution (concentration 50% by mass) was replaced with prepolymer U2 (concentration 50% by mass).

[0094] [Measurement and Evaluation of Pressure-Sensitive Adhesive Sheets] The following various evaluations were carried out on the pressure-sensitive adhesive sheet S1 (Example 1) obtained in Production Example 1, the commercially available pressure-sensitive adhesive sheets (with release liner) S2 to S5 (Examples 2 to 5) listed below, and the pressure-sensitive adhesive sheet S6 (Example 6) obtained in Production Example 2. The results of these evaluations are shown in Table 2. Example 1 is the working example, and Examples 2 to 6 are comparative examples. (Pressure-Sensitive Adhesive Sheets) S2: "Easy-Removable Silicone Tape", manufactured by 3M Japan Ltd., silicone-based adhesive, backing: polyester nonwoven fabric S3: "Single-Sided Adhesive Tape 2476P", manufactured by 3M Japan Ltd., silicone-based adhesive, backing: polyester nonwoven fabric S4: "Skin Adhesive Tape 4076", manufactured by 3M Japan Ltd., acrylic adhesive, backing: polyester nonwoven fabric S5: "Yu-Hada-Ban (registered trademark)", manufactured by Nitoms Inc., acrylic adhesive, backing: polyester nonwoven fabric

[0095] <Adhesive Strength> (1) To Phenolic Resin Plate The adhesive layer side of a pressure-sensitive adhesive sheet (100 mm long, 15 mm wide) from which the release liner had been peeled was placed on a phenolic resin plate ("SUMILITE (registered trademark) PL-1102", manufactured by Sumitomo Bakelite Co., Ltd.; 125 mm long, 30 mm wide, 2 mm thick), and a rubber roller was rolled back and forth from the support side of the pressure-sensitive adhesive sheet at a load of 2 kg and a speed of 300 mm / min, thereby pressing the pressure-sensitive adhesive layer onto the phenolic resin plate. After leaving to stand for 20 minutes, the pressure-sensitive adhesive sheet was peeled off at a peel angle of 90° and a speed of 300 mm / min, and the adhesive strength was measured according to a method in accordance with JIS Z 0237:2009. Table 2 also shows the evaluation of the measured adhesive strength according to the following evaluation criteria. [Evaluation criteria (phenolic resin plate)] A: 3.0 N / 15 mm or more B: 2.0 N / 15 mm or more but less than 3.0 N / 15 mm C: Less than 2.0 N / 15 mm If the rating is A, it can be said that the plate has good adhesive strength to phenolic resin, which is a typical material for sealing circuit patterns.

[0096] (2) To human skin Adhesive strength was measured in the same manner when the skin of a human (subject)'s forearm was used as the adherend instead of the phenolic resin plate. Table 2 shows the average of three measurements. In Example 6, the adhesive did not adhere to the skin. Table 2 also shows the evaluation of the measured adhesive strength according to the following evaluation criteria. [Evaluation criteria (skin)] A: 0.2 to 1.0 N / 15 mm B: More than 1.0 N / 15 mm C: Less than 0.2 N / 15 mm Evaluation A can be said to have appropriate adhesive strength to the skin. Evaluation B means that the adhesive strength is too strong, making it difficult to peel off and potentially causing pain when peeling. Evaluation C means that the adhesive strength is too weak, making it easy to peel off or not adhering at all.

[0097] <Amount of keratin exfoliation> In the above-mentioned adhesive strength measurement (2), a measurement sample measuring 20 mm in length and 15 mm in width was cut out from the adhesive sheet peeled from the skin, and the amount of keratin exfoliation (protein amount [mg / cm ]) was measured using a "Protein Assay Lowry Kit" (manufactured by Nacalai Tesque, Inc.). ２ Table 2 also shows the evaluation of the amount of keratin exfoliation according to the following evaluation criteria. [Evaluation criteria] A: 0.1 mg / cm ２ Less than B: 0.1 mg / cm ２ 0.3mg / cm or more ２ Less than C: 0.3 mg / cm ２ If the rating is A, it can be said that the load of the adhesive layer on the skin is sufficiently small.

[0098] <Long-term adhesiveness> In the same manner as in (2) of the adhesive strength measurement above, an adhesive sheet was pressed onto the skin of the forearm of a human (subject), and the subject continued to go about their daily life (work, shower, sleep, etc.) in that state for up to 14 days. The number of days until the adhesive sheet peeled off (persistence) was measured, and upon peeling (if the adhesive sheet remained attached for 14 days, it was peeled off by hand while maintaining a 90° angle between the skin of the forearm and the adhesive sheet), the presence or absence of skin abnormalities (redness, itchiness, etc.) was confirmed.

[0099] <Moisture Permeability> The moisture permeability of the PSA sheet from which the release liner had been peeled off was measured using a method in accordance with JIS Z 0208:1976. Specifically, a circular test piece of the PSA sheet with a diameter approximately 10 mm larger than the inner diameter of the cup was placed over a cup containing approximately 50 g of moisture absorbent (calcium chloride), and the cup was screwed in place using a rubber packing and a ring, and the measurement was carried out in a constant temperature and humidity chamber under an atmosphere of 40°C and 90% RH. The moisture permeability was calculated according to the following formula. Moisture permeability [g / (m ２ ·day)] = W × 240000 / S, where S is the area of ​​the opening of the cup (moisture permeation area [cm ２ ]), W represents the mass increase of the test piece per hour [g / hr]. Table 2 also shows the evaluation of the moisture permeability according to the following evaluation criteria. [Evaluation criteria] A: 1500 g / (m ２ ・Day) or more B: 1000g / (m ２ ・day) or more 1500g / (m ２ ・day) less than C: 1000g / (m ２ If the rating is A, it can be said that the moisture permeability is good and the load on the skin is sufficiently small.

[0100] The moisture permeability of only the pressure-sensitive adhesive layer of pressure-sensitive adhesive sheet S1 was measured as follows. In Production Example 1, a coarse-mesh nylon net, which can be considered not to affect the moisture permeability (no support), was used instead of the polyester nonwoven fabric support, and a pressure-sensitive adhesive sheet was produced in the same manner as in Production Example 1. The release liner was peeled off from the obtained pressure-sensitive adhesive sheet to obtain a test piece (considered to have no support), and the moisture permeability was measured in the same manner as in the measurement of the moisture permeability of the pressure-sensitive adhesive sheet described above, and this measured value was considered to be the moisture permeability of only the pressure-sensitive adhesive layer. As a result, the moisture permeability of only the pressure-sensitive adhesive layer of pressure-sensitive adhesive sheet S1 was 4900 g / (m ２ ・day).

[0101]

[0102] [Production of adhesive circuit] (Example 7) In Production Example 1, the dry thickness of the adhesive layer was set to 100 μm, and a polyurethane film (thickness: 20 μm) was laminated as a support onto the obtained adhesive layer, and adhesive sheet S7 was produced in the same manner as in Production Example 1. A sheet piece (length: 20 mm, width: 70 mm) was cut out from adhesive sheet S7, and a circuit was formed on the support side by screen printing using silver paste, and the resultant was dried at 70 to 80° C. for 30 minutes, to obtain an adhesive circuit.

[0103] Examples 8 and 9 Using the pressure-sensitive adhesive sheets S3 and S5, adhesive circuits were produced in the same manner as in Example 7.

[0104] [Evaluation of Adhesive Circuits] The circuit retention was evaluated for the adhesive circuits of Examples 7 to 9. The evaluation results are shown in Table 3. Example 7 is an embodiment, and Examples 8 and 9 are comparative examples.

[0105] <Circuit Retention> The adhesive circuit was pressed onto the skin of the forearm of a human (subject) in the same manner as in (2) for measuring adhesive strength in the measurement and evaluation of the pressure-sensitive adhesive sheet, and the subject lived a normal life in this state (excluding showering) for one day. The presence or absence of peeling of the circuit and the presence or absence of discoloration at the interface between the circuit and the support were checked. Discoloration is thought to be mainly caused by corrosion of the circuit.

[0106]

[0107] As can be seen from the evaluation results shown in Tables 2 and 3, the adhesive sheets (S1, S7) manufactured using prepolymer U1 (hydroxyl group-terminated urethane prepolymer) have excellent moisture permeability, even though they are adhesive sheets with a support, and exhibit appropriate adhesive strength while reducing the load on the skin. They also have excellent adhesive properties to electronic devices, etc., and are thought to be able to reduce malfunctions in circuit operation due to circuit peeling and corrosion.

[0108] REFERENCE SIGNS LIST 11 adhesive layer 12 support 21 circuit pattern 22 substrate (package) 23 insulating layer 31 other adhesive layer 40 skin

Claims

1. An adhesive circuit having a circuit pattern and an adhesive layer, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a reaction product of a hydroxyl group-terminated urethane prepolymer and a curing agent, The hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer A having an average number of hydroxyl groups per molecule of 2.1 to 3.0, an oxyalkylene polymer B having one hydroxyl group per molecule, and a diisocyanate compound, and has an ethylene oxide unit content of 5 mass% or more; The application circuit, wherein the curing agent comprises a polyisocyanate compound.

2. 2. The circuit patch according to claim 1, wherein the oxyalkylene polymer B has a number average molecular weight of 3,500 or more.

3. 2. The patch circuit according to claim 1, wherein, based on a total of 100 parts by mass of the oxyalkylene polymer A, the amount of the oxyalkylene polymer A1 having 3 hydroxyl groups per molecule is 20 parts by mass or more.

4. 2. The circuit patch according to claim 1, wherein the oxyalkylene polymer A has an ethylene oxide unit content of 10% by mass or more.

5. 2. The patch circuit according to claim 1, wherein the amount of the polymer A is 10 to 95 parts by mass based on 100 parts by mass of the total of the polymer A and the polymer B.

6. 2. The circuit patch according to claim 1, wherein the polyisocyanate compound has three or more isocyanate groups in one molecule.

7. The circuit patch according to claim 1, wherein the adhesive layer has a thickness of 5 to 100 μm.

8. The moisture permeability of the pressure-sensitive adhesive layer is 3000 g / (m ２ 2. The circuit according to claim 1, wherein the number of cycles is equal to or greater than 1000 cycles.

9. The adhesive circuit according to claim 1 , wherein the adhesive layer is formed on a main surface of a sheet-like support.

10. The adhesive circuit according to claim 9 , wherein the adhesive layer is formed on one main surface of the support, and the circuit pattern is formed on the other main surface of the support.

11. The circuit of claim 1 , wherein the circuit pattern is formed of a conductive ink.

12. A wearable device comprising the attachment circuit according to any one of claims 1 to 11.

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