Nozzle cleaning method and remanufacturing method for nozzle

Abstract

To provide a cleaning method capable of cleaning a nozzle used for coating an epoxy resin composition including an epoxy resin and a solid dispersive latent curing agent while suppressing clogging.SOLUTION: This method for cleaning a nozzle used for coating an epoxy resin composition containing (A) an epoxy resin and (B) a solid dispersive latent curing agent comprises: a step (I) of cleaning the nozzle by a liquid organic material; and (II) a step of cleaning the nozzle by an organic solvent in this order. The liquid organic material does not substantially contain (a) a solid dispersive latent curing agent activated by the organic solvent used in the step (II) and an organic solvent (b) which activates the solid dispersive latent curing agent (B) present in the epoxy resin composition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for cleaning a nozzle used in applying an epoxy resin composition, and a method for producing a recycled nozzle. [Background technology]

[0002] In the manufacture of electronic devices and printed wiring boards, adhesives such as conductive paste stored in a syringe are sometimes applied by a dispenser, which discharges the adhesive from a nozzle such as a needle, in order to bond or electrically connect multiple components and to form wiring and electrodes (Patent Document 1).In addition, adhesives such as conductive paste are sometimes sold in syringes.

[0003] As a paste-like adhesive, a one-component epoxy resin composition containing an epoxy resin and a latent curing agent is sometimes used because it is easy to store and handle. Furthermore, solid-dispersed latent curing agents are known as latent curing agents that provide excellent storage stability to epoxy resin compositions. Examples of solid-dispersed latent curing agents include amine adduct latent curing agents and crystalline latent curing agents (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-177843 [Patent Document 2] Japanese Patent Application Publication No. 11-256013 Summary of the Invention [Problem to be solved by the invention]

[0005] If a paste adhesive is discharged from a nozzle and the nozzle is left as it is, the adhesive may dry or harden, causing the inside of the nozzle to become clogged. Therefore, it is desirable to wash the inside of the nozzle used to discharge the adhesive with an organic solvent to remove the adhesive.

[0006] However, when an epoxy resin composition containing a solid-dispersion-type latent curing agent is used, cleaning with an organic solvent can be difficult in some cases. For example, when the epoxy resin composition remaining in a used nozzle is cleaned with an organic solvent, the curing of the epoxy resin composition progresses inside the nozzle, causing clogging of the nozzle.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a cleaning method capable of cleaning a nozzle used for applying an epoxy resin composition containing an epoxy resin and a solid-dispersion-type latent curing agent while suppressing clogging; and a method for producing a recycled nozzle by cleaning a nozzle used for applying an epoxy resin composition containing an epoxy resin and a solid-dispersion-type latent curing agent while suppressing clogging, thereby producing a recycled nozzle. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that, prior to cleaning the nozzle with an organic solvent, cleaning the nozzle with a liquid organic substance that is substantially free of a solid-dispersed latent curing agent and an organic solvent that activates the solid-dispersed latent curing agent, and then cleaning the nozzle with an organic solvent, makes it possible to clean the nozzle without causing clogging inside the nozzle or adhesion of a cured product, and have completed the present invention. That is, the present invention includes the following.

[0009] [1] A method for cleaning a nozzle used in applying an epoxy resin composition containing (A) an epoxy resin and (B) a solid-dispersion-type latent curing agent; The cleaning method comprises: (I) washing the nozzle with a liquid organic substance; and (II) washing the nozzle with an organic solvent; in this order; The liquid organic substance is a solid-dispersed latent curing agent (a) that is activated by the organic solvent used in the step (II); and (b) an organic solvent that activates the solid-dispersed latent curing agent (B) present in the epoxy resin composition; A nozzle cleaning method that is substantially free of [2] The nozzle cleaning method according to [1], wherein the liquid organic substance is a liquid resin. [3] The nozzle cleaning method according to [1] or [2], wherein the liquid organic substance is a liquid epoxy resin. [4] The nozzle cleaning method according to any one of [1] to [3], wherein the nozzle is a nozzle used to discharge the epoxy resin composition from a syringe containing the epoxy resin composition. [5] The nozzle cleaning method according to any one of [1] to [4], wherein the nozzle is a nozzle used to discharge the epoxy resin composition in a dispenser equipped with a syringe capable of storing the epoxy resin composition. [6] The nozzle cleaning method according to any one of [1] to [5], wherein the organic solvent used in the step (II) has a boiling point of 200°C or lower. [7] The step (II) includes washing the nozzle with the organic solvent multiple times; The nozzle cleaning method according to any one of [1] to [6], wherein at least the final cleaning is carried out with an organic solvent having a boiling point of 100°C or less. [8] The nozzle cleaning method according to any one of [1] to [7], further comprising, after the step (II), a step (III) of drying the nozzle. [9] The nozzle cleaning method according to [8], wherein the step (III) includes heating and drying the nozzle.

[10] A method for producing a recycled nozzle from a used nozzle that has been used to apply an epoxy resin composition containing (A) an epoxy resin and (B) a solid-dispersion-type latent curing agent, comprising: (I) a step of cleaning the used nozzle with a liquid organic substance; and (II) washing the used nozzle with an organic solvent; in this order, The liquid organic substance is a solid-dispersed latent curing agent (a) that is activated by the organic solvent used in the step (II); and (b) an organic solvent that activates the solid-dispersed latent curing agent (B) present in the epoxy resin composition; A method for manufacturing a recycled nozzle, which is substantially free of [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a cleaning method that can clean a nozzle used for applying an epoxy resin composition containing an epoxy resin and a solid-dispersion-type latent curing agent while suppressing clogging; and a method for producing a recycled nozzle that can clean a nozzle used for applying an epoxy resin composition containing an epoxy resin and a solid-dispersion-type latent curing agent while suppressing clogging, thereby producing a recycled nozzle. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic example of a nozzle. [Figure 2] FIG. 2 is a cross-sectional view that schematically illustrates an example of a syringe equipped with a nozzle. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented within the scope of the claims and their equivalents.

[0013] In the following description, the amount "ppm" is based on mass unless otherwise specified.

[0014] [1. Overview of cleaning method] A method for cleaning a nozzle according to one embodiment of the present invention is a method for cleaning a nozzle that has been used to apply an epoxy resin composition containing (A) an epoxy resin and (B) a solid-dispersion-type latent curing agent. (I) cleaning the nozzle with a liquid organic substance; and (II) washing the nozzle with an organic solvent; In the following description, the liquid organic substance used to clean the nozzle in step (I) may be referred to as the "organic cleaning liquid." Also, in the following description, the organic solvent used to clean the nozzle in step (II) may be referred to as the "cleaning solvent."

[0015] In the cleaning method according to this embodiment, the organic cleaning liquid has a specific composition. Specifically, the organic cleaning liquid is substantially free of the following solid-dispersion-type latent curing agent (a) and organic solvent (b). A solid dispersion-type latent curing agent (a) that is activated by the washing solvent used in step (II). (b) an organic solvent that activates (B) a solid-dispersed latent curing agent present in the epoxy resin composition; Here, the term "activation" of the solid-dispersed latent curing agent refers to a state in which the solid-dispersed latent curing agent is able to cure the epoxy resin when it functions as a curing agent in the narrow sense of the term for the epoxy resin, and refers to a state in which the solid-dispersed latent curing agent is able to accelerate the curing of the epoxy resin when it functions as a curing accelerator.

[0016] According to the above-described cleaning method, a nozzle used for applying an epoxy resin composition can be cleaned while preventing clogging. The inventors speculate that the mechanism by which such excellent advantages are obtained is as follows. However, the technical scope of the present invention is not limited by the mechanism described below.

[0017] (B) Solid-dispersed latent curing agents may be activated when they come into contact with water or an organic solvent. For example, when an amine adduct-type solid-dispersed latent curing agent (hereinafter sometimes referred to as an "amine adduct-type latent curing agent") comes into contact with water or an organic solvent, the polymer structure swells, exposing the amine moiety and causing activation. Furthermore, when a crystalline solid-dispersed latent curing agent (hereinafter sometimes referred to as a "crystalline latent curing agent") comes into contact with water or an organic solvent, the crystals dissolve and the curing agent may become activated. When the (B) solid-dispersed latent curing agent is activated, the curing reaction of the (A) epoxy resin may proceed. Therefore, when a used nozzle containing residual epoxy resin composition is washed with an organic solvent, the residual epoxy resin composition may harden. When the epoxy resin composition hardens, it becomes difficult to clean the nozzle, which may cause clogging inside the nozzle.

[0018] In contrast, in the cleaning method according to the present embodiment, the nozzle is cleaned with an organic cleaning solution, and then the nozzle is cleaned with a cleaning solvent. The organic cleaning solution, which is substantially free of the solid-dispersed latent curing agent (a) and the organic solvent (b), does not substantially activate the solid-dispersed latent curing agent (B). Therefore, cleaning with the organic cleaning solution can remove the epoxy resin composition from the nozzle. Then, any organic cleaning solution that may remain in the nozzle is removed with the cleaning solvent, thereby cleaning the nozzle while suppressing clogging.

[0019] Furthermore, according to the cleaning method of this embodiment, it is possible to prevent the formation of a cured product of the epoxy resin composition inside the nozzle, as described above. Therefore, not only can it usually be prevented that the flow path in the nozzle is clogged with the cured product, but it can also be prevented that the flow path is narrowed by the cured product. Therefore, it is possible to prevent the discharge amount from becoming non-uniform due to the cured product adhering to the inside of the nozzle, and therefore it is possible to improve the uniformity of the discharge amount of the epoxy resin composition through the nozzle obtained after cleaning.

[0020] [2. Explanation of nozzles to be cleaned] The nozzle to be cleaned will now be described. FIG. 1 is a cross-sectional view schematically illustrating an example of a nozzle 100. As shown in FIG. 1, the nozzle 100 is a member capable of discharging an epoxy resin composition, and has a flow path 110 therein through which the epoxy resin composition can flow. An inlet 120 through which the epoxy resin composition can be supplied is formed at one end of the flow path 110. Furthermore, an outlet 130 through which the epoxy resin composition can be discharged is formed at another end of the flow path 110. Here, an example of a nozzle 100 having one flow path 110, one inlet 120, and one outlet 130 is shown, but a plurality of flow paths 110, one inlet 120, and one outlet 130 may be formed.

[0021] Typically, nozzle 100 includes a connector portion 140 for attaching nozzle 100 to a syringe. The inlet 120 is generally formed to open at this connector portion 140. In this embodiment, an example of nozzle 100 will be described, which includes connector portion 140 and a tubular needle portion 150 connected to this connector portion 140, and in which a flow path 110 is formed so as to communicate from inlet 120 opening at connector portion 140 to outlet 130 opening at the tip of needle portion 150.

[0022] FIG. 2 is a cross-sectional view schematically illustrating a syringe 200 to which an example nozzle 100 is attached. As shown in FIG. 2, the nozzle 100 is typically attached to the syringe 200 for use. The syringe 200 includes a nozzle mounting portion 210 to which the nozzle 100 can be attached. For example, a screw-shaped locking portion 211 may be provided on the nozzle mounting portion 210 of the syringe 200, and the locking portion 211 may lock onto a protrusion 141 formed on a connector 140 of the nozzle 100, thereby fixing the nozzle 110 to the nozzle mounting portion 210. The syringe 200 is also configured to be able to accommodate an epoxy resin composition 300. In general, the syringe 200 is formed in a cylindrical shape, and therefore has a hollow portion 220 formed therein that can accommodate the epoxy resin composition 300. The hollow portion 220 opens at a delivery port 230 formed in the nozzle mounting portion 210 so as to be in communication with the inlet 120 of the nozzle 100 mounted on the nozzle mounting portion 210. In addition, a plunger 240 is provided in the hollow portion 220 so as to movably close the hollow portion 220 so that the epoxy resin composition 300 can be pushed and delivered to the flow path 110 in the nozzle 100 through the delivery port 230.

[0023] Typically, an opening 250 is formed on the side of the hollow portion 220 opposite to the delivery port 230. Therefore, when the nozzle 100 is attached to the nozzle attachment portion 210 of the syringe 200 as shown in FIG. 2 , the nozzle 100 and the syringe 200 can form a continuous tube from the opening 250 of the syringe 200 to the discharge port 130 of the nozzle 100. Therefore, when the plunger 240 is pushed by a force such as the pressure of a plunger rod (not shown) inserted through the opening 250 or the pressure of air supplied through the opening 250, the epoxy resin composition 300 enters the flow path 110 through the inlet 120 of the nozzle 100 and can be discharged through the discharge port 130.

[0024] Typically, when using the nozzle 100 and syringe 200, a dispenser (not shown) is used to apply the epoxy resin composition 300. Specifically, the syringe 200 containing the epoxy resin composition 300 is attached to the dispenser, and the dispenser presses the plunger 240 by pressure such as air pressure or mechanical pressure from a plunger rod. When the plunger 240 is pressed, the epoxy resin composition 300 is discharged from the discharge port 130 of the nozzle 100. The epoxy resin composition 300 then adheres to an article, thereby achieving application of the epoxy resin composition 300.

[0025] When the epoxy resin composition 300 is applied using the nozzle 100 as described above, the epoxy resin composition 300 may remain inside the nozzle 100 after application. In the cleaning method according to the present embodiment, the epoxy resin composition 300 is removed from the nozzle 100 to which the remaining epoxy resin composition 300 has adhered, thereby obtaining a nozzle that can be used again to apply a liquid composition such as the epoxy resin composition 300.

[0026] The dimensions of the nozzle 100 may vary depending on the specific composition and properties of the epoxy resin composition 300 and the shape of the application area (dot, line, etc.) formed by the epoxy resin composition 300 discharged from the nozzle 100, but for example, the length may be 0.5 mm to 30 mm, the outer diameter may be 0.2 mm to 3 mm, and the inner diameter may be 0.1 mm to 2.5 mm. The nozzle 100 may also be a curved nozzle, a tapered nozzle with a tapered interior, or a multi-nozzle with multiple nozzles protruding from a single main body.

[0027] [3. Epoxy resin composition] The epoxy resin composition to be applied using the nozzle contains (A) an epoxy resin and (B) a solid-dispersion-type latent curing agent.

[0028] [3.1.(A) Epoxy Resin] The (A) epoxy resin is a compound containing an epoxy group. The (A) epoxy resin is preferably a compound having an average of two or more epoxy groups per molecule. The epoxy resin may be liquid, solid, or a combination of liquid and solid. However, from the viewpoint of obtaining a liquid epoxy resin composition suitable for application, the (A) epoxy resin preferably contains a liquid epoxy resin. The amount of the liquid epoxy resin is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on 100% by mass of the total amount of the (A) epoxy resin. The upper limit of the amount of the liquid epoxy resin is not particularly limited, and may be 100% by mass, less than 100% by mass, 90% by mass or less, 80% by mass or less, or 70% by mass or less, based on 100% by mass of the total amount of the epoxy resin. Unless otherwise specified, the liquid epoxy resin refers to an epoxy resin that is liquid at room temperature (25°C).

[0029] The weight-average molecular weight of the (A) epoxy resin is preferably 5,000 or less, more preferably 2,000 or less, and particularly preferably 1,000 or less. There is no particular lower limit, but the lower limit is preferably 100 or more, more preferably 200 or more, and particularly preferably 300 or more. The weight-average molecular weight of the resin can be measured in polystyrene equivalent terms by gel permeation chromatography (GPC).

[0030] The epoxy equivalent (g / eq.) of the (A) epoxy resin is not particularly limited, but is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., even more preferably 80 g / eq. to 2000 g / eq., and particularly preferably 110 g / eq. to 1000 g / eq. The epoxy equivalent is the mass of a resin containing one equivalent of epoxy groups, and can be measured according to JIS K7236.

[0031] The (A) epoxy resin may be used alone or in combination of two or more.

[0032] As the solid epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin and tetraphenylethane-type epoxy resin are preferred, naphthalene-type tetrafunctional epoxy resin, naphthol-type epoxy resin and biphenyl-type epoxy resin are more preferred, and biphenyl-type epoxy resin is even more preferred. Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200" (dicyclopentadiene-type epoxy resin), "HP-7200HH", "HP-7200H", "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether-type epoxy resin), manufactured by DIC Corporation; and "EPPN-502H" (trisphenol-type epoxy resin), "NC7000L" (naphthol novolac-type epoxy resin), "NC3000H", and "NC30 00, "NC3000L," and "NC3100" (biphenyl-type epoxy resins); "ESN475V" (naphthalene-type epoxy resin) and "ESN485" (naphthol novolac-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H," "YL6121" (biphenyl-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), and "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YL7760" (bisphenol AF-type epoxy resin), "YL7800" (fluorene-type epoxy resin), "jER1010" (solid bisphenol A-type epoxy resin), and "jER1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation. These may be used alone or in combination of two or more.

[0033] Preferred liquid epoxy resins include glycerol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AF-type epoxy resins, naphthalene-type epoxy resins, glycidyl ester-type epoxy resins, glycidyl amine-type epoxy resins, phenol novolac-type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol-type epoxy resins, and epoxy resins having a butadiene structure, and more preferred are glycerol-type epoxy resins, bisphenol A-type epoxy resins, and bisphenol F-type epoxy resins. Specific examples of liquid epoxy resins include "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US," "jER828EL" (bisphenol A-type epoxy resin), "jER807" (bisphenol F-type epoxy resin), and "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "JER-630" and "JER-630LSD" manufactured by Mitsubishi Chemical Corporation; and "ED-523T" (glycirol-type epoxy resin (ADEKA glycirol)) and "EP-3980S" (glycidyl amine-type epoxy resin) manufactured by ADEKA Corporation. Examples of suitable epoxy resins include "bisphenol A epoxy resin," "EP-4088S" (dicyclopentadiene epoxy resin), "ZX1059" (a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., "EX-721" (glycidyl ester epoxy resin) manufactured by Nagase ChemteX Corporation, "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton) and "PB-3600" (epoxy resin having a butadiene structure) manufactured by Daicel Corporation, and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical Co., Ltd. These may be used alone or in combination of two or more.

[0034] In order to adjust the viscosity, the liquid epoxy resin preferably contains a low-viscosity liquid epoxy resin having a viscosity of 100 mPa·S or less at room temperature (25°C). Examples of low-viscosity liquid epoxy resins include EP4085S and EP4088S manufactured by ADEKA Corporation, ZX-1542 and ZX-1658 manufactured by Nippon Steel Chemical & Material Co., Ltd. (formerly Nippon Steel Chemical Co., Ltd.), Denacol EX201 manufactured by Nagase ChemteX Corporation, GOT and GAN manufactured by Nippon Kayaku Co., Ltd., X-22-163 and KF-105 manufactured by Shin-Etsu Chemical Co., Ltd., and 630 and YED216D manufactured by Mitsubishi Chemical Corporation (formerly Mitsubishi Chemical Co., Ltd.).

[0035] The weight average molecular weight of the liquid epoxy resin is preferably 1,000 or less, more preferably 900 or less, and particularly preferably 800 or less. There is no particular lower limit, but the lower limit is preferably 100 or more, more preferably 200 or more, and particularly preferably 300 or more.

[0036] The epoxy equivalent (g / eq.) of the liquid epoxy resin is not particularly limited, but is preferably 50 g / eq. to 1000 g / eq., more preferably 50 g / eq. to 800 g / eq., even more preferably 80 g / eq. to 600 g / eq., and particularly preferably 110 g / eq. to 500 g / eq.

[0037] The amount of (A) epoxy resin can be set depending on the application of the epoxy resin composition. The specific amount of (A) epoxy resin is preferably 5% by mass or more, more preferably 8% by mass or more, and may be 11% by mass or more, 13% by mass or more, or 14% by mass or more, relative to 100% by mass of the epoxy resin composition. The upper limit is preferably 90% by mass or less, more preferably 85% by mass or less, and may be 70% by mass or less, 30% by mass or less, 23% by mass or less, 20% by mass or less, or 19% by mass or less.

[0038] [3.2.(B) Solid dispersion type latent curing agent] (B) solid-dispersed latent curing agents are solids that are insoluble in epoxy resins at room temperature (25°C), but are soluble when heated, accelerating the curing of the epoxy resin. These (B) solid-dispersed latent curing agents encompass both curing agents in the narrow sense that can react with epoxy resins to cure them, and curing accelerators that do not react with epoxy resins but function as catalysts to accelerate the curing of epoxy resins. Examples of (B) solid-dispersed latent curing agents include amine adduct latent curing agents and crystalline latent curing agents.

[0039] Examples of amine adduct latent curing agents include reaction products of amine compounds and epoxy compounds (amine-epoxy adduct latent curing agents); reaction products of amine compounds and isocyanate compounds or urea compounds (urea-based adduct latent curing agents); and those obtained by treating the surfaces of these curing agents with isocyanate compounds or acidic compounds.

[0040] Examples of epoxy compounds used as raw materials for producing amine adduct-type latent curing agents include polyglycidyl ethers obtained by reacting epichlorohydrin with polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcinol, or polyhydric alcohols such as glycerin and polyethylene glycol; glycidyl ether esters obtained by reacting epichlorohydrin with hydroxy acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid; polyglycidyl esters obtained by reacting epichlorohydrin with polycarboxylic acids such as phthalic acid and terephthalic acid; glycidyl amine compounds obtained by reacting epichlorohydrin with 4,4'-diaminodiphenylmethane and m-aminophenol; polyfunctional epoxy compounds such as epoxidized phenol novolac resins, epoxidized cresol novolac resins, and epoxidized polyolefins; and monofunctional epoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate. The epoxy compounds may be used alone or in combination of two or more.

[0041] The amine compound used as a raw material for producing the amine adduct-type latent curing agent preferably has one or more active hydrogen atoms in the molecule capable of addition reacting with an epoxy group or an isocyanate group, and at least one functional group selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group. Examples of such amine compounds include aliphatic amine compounds such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diamino-dicyclohexylmethane; aromatic amine compounds such as 4,4'-diaminodiphenylmethane and 2-methylaniline; and nitrogen-containing heterocyclic compounds such as 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, and piperazine.

[0042] Among these amine compounds, compounds having a tertiary amino group in the molecule can be used as raw materials for providing amine adduct-type latent curing agents with excellent curing acceleration ability. Examples of such amine compounds include primary or secondary amine compounds having a tertiary amino group in the molecule, such as amine compounds such as dimethylaminopropylamine, diethylaminopropylamine, di-n-propylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, and N-methylpiperazine, and imidazole compounds such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole; 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1-butoxymethyl-2-dimethylaminoethanol, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, and 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline. 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, N-β-hydroxyethylmorpholine, 2-dimethylaminoethanethiol, 2-mercaptopyridine, 2-benzimidazole Examples of the amine compound include alcohols, phenols, thiols, carboxylic acids, and hydrazides having a tertiary amino group in the molecule, such as 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 4-mercaptopyridine, N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, picolinic acid, N,N-dimethylglycine hydrazide, N,N-dimethylpropionic acid hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide. One type of amine compound may be used alone, or two or more types may be used in combination.

[0043] When the amine adduct-type latent curing agent is produced by addition reaction of the epoxy compound and the amine compound, the reaction system may further contain an active hydrogen compound having two or more active hydrogen atoms in the molecule. This active hydrogen compound does not include amine compounds. Examples of such active hydrogen compounds include polyhydric phenols such as bisphenol A, bisphenol F, bisphenol S, hydroquinone, catechol, resorcinol, pyrogallol, and phenol novolac resin; polyhydric alcohols such as trimethylolpropane; polycarboxylic acids such as adipic acid and phthalic acid; 1,2-dimercaptoethane, 2-mercaptoethanol, 1-mercapto-3-phenoxy-2-propanol, mercaptoacetic acid, anthranilic acid, and lactic acid. The active hydrogen compounds may be used alone or in combination.

[0044] Examples of isocyanate compounds used as raw materials for producing amine adduct-type latent curing agents include monofunctional isocyanate compounds such as n-butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, and benzyl isocyanate; polyfunctional isocyanate compounds such as hexamethylene diisocyanate, tolylene diisocyanate (e.g., 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate), 1,5-naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate; and terminal isocyanate group-containing compounds obtained by reacting these polyfunctional isocyanate compounds with active hydrogen compounds. Examples of the compound containing a terminal isocyanate group include an addition compound having a terminal isocyanate group obtained by reacting tolylene diisocyanate with trimethylolpropane, an addition compound having a terminal isocyanate group obtained by reacting tolylene diisocyanate with pentaerythritol, etc. One type of isocyanate compound may be used alone, or two or more types may be used in combination.

[0045] Examples of urea compounds used as raw materials for producing amine adduct-type latent curing agents include urea, thiourea, etc. One type of urea compound may be used alone, or two or more types may be used in combination.

[0046] The amine adduct latent curing agent can be produced, for example, by mixing the above-mentioned production raw materials, reacting them at a temperature of room temperature to 200°C, cooling them to solidify them, and then pulverizing them. Alternatively, the amine adduct latent curing agent can be produced, for example, by mixing the above-mentioned production raw materials, reacting them in a solvent such as methyl ethyl ketone, dioxane, or tetrahydrofuran at a temperature of room temperature to 200°C, removing the solvent, and then pulverizing the solid content.

[0047] Commercially available amine adduct latent curing agents may be used. Examples of commercially available amine-epoxy adduct latent curing agents include "Amicure PN-23," "Amicure PN-H," "Amicure PN-F," and "Amicure MY-24" manufactured by Ajinomoto Fine-Techno Co., Ltd.; "Hardener X-3661S" and "Hardener X-3670S" manufactured by ACR Corporation; and "Novacure HX-3742" and "Novacure HX-3721" manufactured by Asahi Kasei Corporation. Examples of commercially available urea adduct latent curing agents include "FXE-1000," "FXR-1030," and "FXR-1081" manufactured by T&K TOKA Corporation.

[0048] As the amine adduct type latent curing agent, for example, those described in JP-A-7-196776 and JP-A-2019-143134 may be used.

[0049] Crystalline latent curing agents are crystalline substances that are solid at room temperature (25°C), where their melting points are, and examples thereof include dicyandiamide, dihydrazide compounds, dimethylurea compounds, and imidazole compounds. Examples of dihydrazide compounds include adipic acid dihydrazide. Examples of dimethylurea compounds include 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), aromatic dimethylurea (e.g., "U-CAT3512T" manufactured by San-Apro), and aliphatic dimethylurea (e.g., "U-CAT3513N" manufactured by San-Apro). Examples of the imidazole compound include 2-heptadecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2-methylimidazolyl-(1))-ethyl-S-triazine, 2,4-diamino-6-(2'-methylimidazolyl-(1)')-ethyl-S -triazine·isocyanuric acid adduct, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole-trimellitate, 1-cyanoethyl-2-phenylimidazole-trimellitate, N-(2-methylimidazolyl-1-ethyl)-urea, N,N'-(2-methylimidazolyl-(1)-ethyl)-adiboyldiamide, etc.

[0050] The solid-dispersed latent curing agent (B) may be used singly or in combination of two or more. Thus, as the solid-dispersed latent curing agent (B), one or more amine adduct latent curing agents may be used, one or more crystalline latent curing agents may be used, or an amine adduct latent curing agent and a crystalline latent curing agent may be used in combination.

[0051] The amount of (B) solid-dispersion-type latent curing agent is preferably 0.1 part by mass or more, more preferably 1.0 part by mass or more, and particularly preferably 5.0 parts by mass or more, per 100 parts by mass of (A) epoxy resin, and is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

[0052] The amount of (B) solid-dispersion-type latent curing agent is, relative to 100% by mass of the epoxy resin composition, preferably 0.1% by mass or more, more preferably 1.0% by mass or more, particularly preferably 3.0% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less.

[0053] [3.3.(C) Hardeners (excluding (B) solid dispersion type latent hardeners)] The epoxy resin composition may further contain a (C) curing agent as an optional component. However, the (C) curing agent does not include the above-mentioned (B) solid-dispersion-type latent curing agent. As the (C) curing agent, a curing agent that is liquid at room temperature (25°C) is preferred from the viewpoint of obtaining an epoxy resin composition that is liquid at room temperature (25°C). Examples of such curing agents include polythiol compounds, liquid phenolic resins, acid anhydrides, imidazoles, etc., with polythiol compounds and liquid phenolic resins being preferred, and polythiol compounds being particularly preferred.

[0054] The polythiol compound may be a compound having two or more thiol groups in the molecule. The number of thiol groups in one molecule of the polythiol compound is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less. Examples of such polythiol compounds include trimethylolpropane tris(3-mercaptopropionate) (abbreviation: TMTP), pentaerythritol tetrakis(3-mercaptopropionate) (abbreviation: PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (abbreviation: DPMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (abbreviation: TEMPIC), tris(3-mercaptopropyl)isocyanurate (abbreviation: TMPIC), octyl thioglycolate (abbreviation: OTG), ethylene glycol bisthioglycolate (abbreviation: EGTG), trimethylolpropane tristhioglycolate (abbreviation: TMTG), penta ... Examples of suitable esters include tetrakis(2-mercaptoethyl)glycolate (PETG), 3-mercaptopropionic acid (3-MPA), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) (TPMB), trimethylolethane tris(3-mercaptobutyrate) (TEMB), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, and 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene].

[0055] The (C) curing agent may be used alone or in combination of two or more.

[0056] The functional group equivalent of the (C) curing agent is not particularly limited. For example, the thiol group equivalent of the polythiol compound is preferably 50 g / eq to 500 g / eq, more preferably 75 g / eq to 300 g / eq, and particularly preferably 100 g / eq to 200 g / eq. The functional group equivalent represents the mass of a resin containing one equivalent of a functional group.

[0057] The amount of (C) curing agent is preferably set so that the ratio of the total number of epoxy groups in the (A) epoxy resin to the total number of functional groups in the (C) curing agent (functional groups in (C) curing agent / epoxy groups in (A) epoxy resin) falls within a specific range. This ratio (functional groups in (C) curing agent / epoxy groups in (A) epoxy resin) is preferably 0.1 or more, more preferably 0.5 or more, and particularly preferably 0.7 or more, and is preferably 10 or less, more preferably 3.0 or less, even more preferably 2.0 or less, and particularly preferably 1.0 or less. Here, the total number of epoxy groups in the (A) epoxy resin refers to the sum of the mass of each (A) epoxy resin divided by the epoxy equivalent weight for all (A) epoxy resins. Furthermore, the total number of functional groups in the (C) curing agent refers to the sum of the mass of each (C) curing agent divided by the functional group equivalent weight for all (C) curing agents.

[0058] The amount of (C) curing agent, relative to 100% by mass of the epoxy resin composition, may be 0% by mass or more, and is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less.

[0059] [3.4.(D) Inorganic filler] The epoxy resin composition may further contain (D) an inorganic filler as an optional component. The (D) inorganic filler may be particles formed of an inorganic material. Examples of inorganic materials include non-conductive inorganic materials such as aerosil, silica, alumina, aluminosilicate, glass, carbon fiber, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate; and conductive inorganic materials such as metals. Examples of metals include silver, tin, zinc, aluminum, and nickel. These materials may be used singly or in combination of two or more. Therefore, the inorganic filler (D) may be used singly or in combination of two or more.

[0060] In a preferred example, the inorganic filler (D) preferably contains silver particles; more preferably contains silver particles in combination with one or more types of particles selected from the group consisting of tin particles, zinc particles, and aluminum particles.

[0061] The particle shape of the (D) inorganic filler is not particularly limited, and may be, for example, spherical, flake-like, or needle-like. Among these, flake-like metal particles are preferred. Flake-like refers to a plate-like shape (see JIS Z2500:2000), and is sometimes also called scale-like because it is a thin, plate-like shape.

[0062] The average particle size of the (D) inorganic filler is not particularly limited as long as it can be discharged from a nozzle. While the specific average particle size varies depending on the nozzle dimensions, in a preferred example, it is preferably 20 nm or more, more preferably 50 nm or more, and particularly preferably 100 nm or more, and preferably 15 μm or less, more preferably 12.5 μm or less, and particularly preferably 10 μm or less. The average particle size can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a volumetric particle size distribution of the inorganic filler is prepared using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and ultrasonically dispersing the sample for 10 minutes. The volumetric particle size distribution of the inorganic filler is measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths using a flow cell system, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction particle size distribution measuring device is the "LA-960" manufactured by Horiba, Ltd.

[0063] The specific surface area of ​​the (D) inorganic filler is not particularly limited as long as it can be discharged from a nozzle. In a preferred example, the specific surface area is preferably 0.1 m 2 / g or more, more preferably 0.15m 2 / g or more, particularly preferably 0.2m 2 / g or more, preferably 1.5m 2 / g or less, more preferably 1.0m 2 / g or less, particularly preferably 0.9m 2 The specific surface area can be measured by the BET (a method for measuring specific surface area based on the multilayer adsorption model extended by Brunauer, Emmett, and Teller, abbreviated as BET) single-point method using a specific surface area measuring device (for example, Mountec's "Macsorb HM-1210").

[0064] The (D) inorganic filler may not be surface-treated, but may be surface-treated with a surface treatment agent if necessary. Examples of surface treatment agents include vinylsilane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

[0065] The amount of (D) inorganic filler can be set depending on the physical properties required for the epoxy resin composition and its cured product. The amount of (D) inorganic filler, relative to 100% by mass of the epoxy resin composition, may be 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, and may be 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more. The upper limit may be 90% by mass or less, 85% by mass or less, 83% by mass or less, 80% by mass or less, etc.

[0066] In particular, when silver particles are used, the amount of the silver particles is preferably 50% by mass or more, more preferably 60% by mass or more, and preferably 80% by mass or less, particularly preferably 75% by mass or less, relative to 100% by mass of the epoxy resin composition.

[0067] Furthermore, when tin particles are used, the amount of the tin particles is, relative to 100% by mass of the epoxy resin composition, preferably 3% by mass or more, more preferably 7% by mass or more, even more preferably 8% by mass or more, particularly preferably 9% by mass or more, and is preferably 24% by mass or less, more preferably 22% by mass or less, even more preferably 21% by mass or less, particularly preferably 20% by mass or less.

[0068] Furthermore, when zinc particles are used, the amount of the zinc particles is preferably 3% by mass or more, and preferably 24% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less, relative to 100% by mass of the epoxy resin composition.

[0069] Furthermore, when aluminum particles are used, the amount of the aluminum particles is preferably 3% by mass or more, more preferably 4% by mass or more, and preferably 24% by mass or less, more preferably 22% by mass or less, relative to 100% by mass of the epoxy resin composition.

[0070] 3.5.(E) Other Optional Ingredients The epoxy resin composition may further contain other optional components in addition to the above-mentioned components.

[0071] The epoxy resin composition may contain a core-shell polymer as an optional component to improve adhesion and provide stress relaxation. A core-shell polymer refers to a polymer having a core portion and a shell portion. The core portion may be a relatively soft portion, and the shell portion may be a relatively hard portion. This core-shell polymer can be obtained by polymerizing a core portion prepared from, for example, a rubber elastomer prepared from a diene monomer, a (meth)acrylic acid ester monomer, and / or a vinyl monomer, a polysiloxane rubber elastomer, or a mixture thereof, with a shell portion prepared from a (meth)acrylic acid ester, an aromatic vinyl, a vinyl cyanide, an epoxy alkyl vinyl ether, an unsaturated acid derivative, a (meth)acrylamide derivative, and / or a maleimide derivative. Commercially available core-shell polymers include, for example, MX120, MX125, MX130, MX135, MX960, and MX965 manufactured by Kaneka Corporation; RKB3040 and RKB1133 manufactured by Resinous Chemicals; JF-001 and JF-003 manufactured by Mitsubishi Chemical Corporation (formerly Mitsubishi Rayon Co., Ltd.); and F351G manufactured by Ganz Chemicals. One type of core-shell polymer may be used alone, or two or more types may be used in combination. The core-shell polymer may be used in the form of a powder or dispersed in an epoxy resin. The amount of the core-shell polymer is preferably 15 to 30 parts by mass, and more preferably 17 to 30 parts by mass, per 100 parts by mass of the (A) epoxy resin.

[0072] The epoxy resin composition may contain a silane coupling agent as an optional component to improve adhesion between the epoxy resin composition and an article to which the epoxy resin composition is applied. Examples of silane coupling agents include 3-aminopropyltriethoxysilane, vinyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane. One type of silane coupling agent may be used alone, or two or more types may be used in combination. The amount of silane coupling agent is preferably 0.5 to 3 parts by mass, more preferably 1 to 2 parts by mass, per 100 parts by mass of the (A) epoxy resin.

[0073] The epoxy resin composition may contain a borate ester as an optional component. Examples of borate esters include trimethyl borate and triethyl borate. One type of borate ester may be used alone, or two or more types may be used in combination. The amount of borate ester is preferably 0.5 to 1.2 parts by mass, more preferably 0.7 to 1 part by mass, per 100 parts by mass of the (A) epoxy resin.

[0074] Further examples of optional components include thixotropic agents such as Aerosil, corrosion inhibitors such as benzimidazole, colorants such as carbon black, flame retardants, thickeners, antifoaming agents, leveling agents, etc. These optional components may be used alone or in combination of two or more.

[0075] However, the epoxy resin composition is generally substantially free of organic solvents. Examples of organic solvents include the same examples as the cleaning solvent used in step (II). The amount of organic solvent contained in the epoxy resin composition is generally 1,000 ppm or less, more preferably 500 ppm or less, particularly preferably 300 ppm or less, and ideally 0 ppm, based on 100% by mass of the epoxy resin composition.

[0076] [3.6. Physical properties of epoxy resin composition] The epoxy resin composition may be in a liquid state under the temperature conditions under which application using a nozzle is carried out. Since application of the epoxy resin composition is generally carried out at room temperature, the epoxy resin composition is usually in a liquid state at room temperature (25°C).

[0077] The viscosity of the epoxy resin composition is preferably set appropriately within a range that allows the epoxy resin composition to be discharged from a nozzle. For example, from the viewpoint of obtaining good coatability, the viscosity of the epoxy resin composition at 25°C is preferably 1 Pa·s or more, more preferably 5 Pa·s or more, and particularly preferably 10 Pa·s or more, and is preferably 100 Pa·s or less, more preferably 80 Pa·s or less, and particularly preferably 60 Pa·s or less.

[0078] Viscosity can be measured using the following method: Keep the sample temperature at 25°C (±2°C) and measure the viscosity (Pa·s) using an E-type viscometer (Toki Sangyo Co., Ltd. "RE-85U" with a 3° x R9.7 rotor) with a sample volume of 0.22 ml and a rotation speed of 20 rpm.

[0079] [4. Step (I): Cleaning with Organic Cleaning Solution] The epoxy resin composition usually adheres to a used nozzle used to apply the above-described epoxy resin composition. For example, the epoxy resin composition that remains without being ejected may fill or adhere to the inside of the nozzle. Furthermore, for example, a portion of the epoxy resin composition ejected from the nozzle may remain near the ejection port, causing the epoxy resin composition to adhere to the outside of the nozzle. The nozzle cleaning method according to this embodiment includes step (I) of cleaning the used nozzle to which the epoxy resin composition has adhered in this way with an organic cleaning liquid as a liquid organic substance. The cleaning in step (I) removes the epoxy resin composition from the nozzle.

[0080] The organic cleaning solution used for cleaning in step (I) is substantially free of the solid-dispersed latent curing agent (a) that is activated by the cleaning solvent used in step (II). Here, the phrase "substantially free" of the solid-dispersed latent curing agent (a) means that the organic cleaning solution may contain the solid-dispersed latent curing agent (a) in an amount sufficient to prevent the organic cleaning solution from contacting the cleaning solvent in step (II) and causing extensive curing to clog the nozzle. It is particularly preferred that the organic cleaning solution be completely free of the solid-dispersed latent curing agent (a). The specific amount of the solid-dispersed latent curing agent (a) contained in the organic cleaning solution is preferably 1% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and ideally 0% by mass, relative to 100% by mass of the organic cleaning solution.

[0081] Furthermore, the organic cleaning liquid used for cleaning in step (I) is substantially free of organic solvent (b), which activates the solid-dispersed latent curing agent (B) present in the epoxy resin composition. Here, the phrase "substantially free" of organic solvent (b) means that the organic cleaning liquid may contain organic solvent (b) in an amount sufficient to prevent the epoxy resin composition contacted with the organic cleaning liquid in step (I) from undergoing extensive curing to the extent that it would clog a nozzle. It is particularly preferred that the organic cleaning liquid be completely free of organic solvent (b). The specific amount of organic solvent (b) contained in the organic cleaning liquid is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, particularly preferably 0.03% by mass or less, and ideally 0% by mass, relative to 100% by mass of the organic cleaning liquid.

[0082] An organic cleaning liquid that is substantially free of a solid-dispersed latent curing agent (a) and an organic solvent (b) can remove an epoxy resin composition adhering to a nozzle while suppressing its curing. Therefore, step (I) allows the epoxy resin composition to be smoothly removed while suppressing nozzle clogging. Furthermore, even when this organic cleaning liquid comes into contact with a cleaning solvent in step (II), the curing of the organic cleaning liquid is suppressed. Therefore, when the organic cleaning liquid is removed with a cleaning solvent in step (II), nozzle clogging due to the curing of the organic cleaning liquid can be suppressed. Therefore, the nozzle can be cleaned while suppressing nozzle clogging.

[0083] To effectively inhibit the curing of the epoxy resin composition in step (I), the organic cleaning liquid is typically substantially free of a curing agent (c) that promotes the curing of the (A) epoxy resin. Here, curing agent (c) encompasses both a narrowly defined curing agent capable of reacting with the (A) epoxy resin to cure the (A) epoxy resin, and a curing accelerator that does not react with the (A) epoxy resin but functions as a catalyst to promote the curing of the (A) epoxy resin. However, curing agent (c) does not include solid-dispersed latent curing agents. Furthermore, the phrase "substantially free" of curing agent (c) means that the organic cleaning liquid may contain curing agent (c) in an amount sufficient to prevent the epoxy resin composition coming into contact with the organic cleaning liquid in step (I) from curing to such an extent that it clogs a nozzle. It is particularly preferred that the organic cleaning liquid be completely free of curing agent (c). The specific amount of the curing agent (c) contained in the organic cleaning liquid is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, particularly preferably 0.03% by mass or less, and ideally 0% by mass, relative to 100% by mass of the organic cleaning liquid.

[0084] Examples of the organic cleaning liquid include liquid resin, liquid rubber, and liquid oil. One type of organic cleaning liquid may be used alone, or two or more types may be used in combination. Therefore, for example, a liquid composition containing two or more types of compounds may be used as the organic cleaning liquid. For example, after cleaning a nozzle with one organic cleaning liquid, the nozzle may be cleaned with another type of organic cleaning liquid.

[0085] The organic cleaning liquid preferably contains a liquid resin, and more preferably contains only a liquid resin. That is, the organic cleaning liquid is more preferably a liquid resin. Examples of the liquid resin include silicone resin and epoxy resin. One type of liquid resin may be used alone, or two or more types may be used in combination. Among them, from the viewpoint of smoothly removing the epoxy resin composition, a liquid epoxy resin is preferred as the liquid resin. Examples of the liquid epoxy resin include the same liquid epoxy resins as those explained in the section on the epoxy resin (A) contained in the epoxy resin composition.

[0086] From the viewpoint of smoothly removing the epoxy resin composition, the amount of the liquid epoxy resin contained in the organic cleaning liquid is preferably 50% by mass to 100% by mass, more preferably 80% by mass to 100% by mass, even more preferably 90% by mass to 100% by mass, and particularly preferably 100% by mass.

[0087] From the viewpoint of efficiently discharging the epoxy resin composition remaining in the nozzle and improving cleaning performance, the organic cleaning liquid preferably has a viscosity equal to or greater than that of the epoxy resin composition. From the viewpoint of cleaning performance, the viscosity of the organic cleaning liquid is preferably 1 Pa·s or more, more preferably 2 Pa·s or more, and even more preferably 3 Pa·s or more, as measured with an E-type viscometer (25°C, 20 rpm). The upper limit is not particularly limited as long as cleaning performance is ensured, but is preferably 200 Pa·s or less, and more preferably 150 Pa·s or less.

[0088] The specific cleaning procedure in step (I) is not limited as long as it can remove the epoxy resin composition from the nozzle. Typically, the nozzle can be cleaned by a method including discharging an organic cleaning liquid through the nozzle. Specifically, the nozzle is attached to a syringe containing the organic cleaning liquid, and the organic cleaning liquid in the syringe is discharged through the nozzle. As the organic cleaning liquid passes through the syringe, the inside of the syringe is replaced and cleaned with the organic cleaning liquid, thereby removing the epoxy resin composition. Furthermore, the cleaning of the nozzle with the organic cleaning liquid in step (I) may be performed once or multiple times.

[0089] [5. Step (II): Washing with Washing Solvent] Typically, the organic cleaning solution used in step (I) remains in the nozzle after cleaning in step (I). Therefore, step (I) is followed by step (II) in which the nozzle is washed with a cleaning solvent. By washing the nozzle with the cleaning solvent, the organic cleaning solution can be removed from the nozzle. Furthermore, since the organic cleaning solution does not substantially contain the solid-dispersed latent curing agent (a), even if the organic cleaning solution that may remain in the nozzle comes into contact with the cleaning solvent, hardening of the organic cleaning solution is suppressed. Therefore, it is possible to clean the nozzle while suppressing clogging of the nozzle due to hardening of the organic cleaning solution.

[0090] From the viewpoint of facilitating drying after washing, the washing solvent is preferably an organic solvent having a boiling point of 200° C. or less, more preferably an organic solvent having a boiling point of 150° C. or less, and even more preferably an organic solvent having a boiling point of 100° C. or less. Preferred examples of washing solvents include the following. The numbers in parentheses following the names of the washing solvents exemplified below indicate the boiling points of the organic solvents.

[0091] Examples of cleaning solvents include diethyl ether (34.4°C), pentane (36.1°C), acetone (56.1°C), chloroform (61.2°C), methanol (64.5°C), tetrahydrofuran (66.0°C), diisopropyl ether (68.5°C), hexane (68.7°C), ethyl acetate (77.1°C), ethanol (95%: 78.3°C), methyl ethyl ketone (79.6°C), cyclohexane (80.7°C), acetonitrile (81.6°C), and isopropyl alcohol. (82.2°C), tert-butyl alcohol (82.3°C), 1,2-dimethoxyethane (84.5°C), 1-propanol (97.2°C), heptane (98.4°C), 2-butanol (99.5°C), 1,4-dioxane (101.3°C), isobutyl alcohol (107.9°C), toluene (110.6°C), butanol (117.7°C), o-xylene (144.4°C), dimethylformamide (153°C), dimethyl sulfoxide (189.0°C).

[0092] From the viewpoint of efficiently removing the organic cleaning liquid remaining in the nozzle, the cleaning solvent preferably has a solubility parameter (SP value) close to that of the organic cleaning liquid. For example, when the organic cleaning liquid is an epoxy resin (theoretical SP value 9.7 to 10.9), the cleaning solvent is preferably an organic solvent such as acetone (SP value 10.0), isopropanol (SP value 11.5), or ethyl acetate (SP value 9.0), with acetone being particularly preferred.

[0093] The cleaning solvent may be used alone or in combination of two or more. For example, a mixed solvent containing two or more organic solvents may be used as the cleaning solvent. Also, for example, after cleaning the nozzle with one cleaning solvent, the nozzle may be cleaned with another cleaning solvent.

[0094] The nozzle may be washed with a washing solvent in step (II) only once or multiple times. When step (II) includes washing the nozzle with a washing solvent multiple times, it is preferable that at least the final washing is performed with a washing solvent having a boiling point of 100°C or less. When washing with an organic solvent at 100°C or less is performed last, the nozzle can be efficiently dried after washing.

[0095] [6. Process (III): Drying] By performing the above-described steps (I) and (II), the nozzles can be cleaned while preventing clogging of the nozzles. However, cleaning solvent may remain on the nozzles after step (II). To remove this cleaning solvent, the nozzle cleaning method according to this embodiment may optionally include step (III) of drying the nozzles after step (II).

[0096] There are no limitations on the method for drying the nozzle. Examples of drying methods include heat drying, vacuum drying, and air drying, and these may be used in combination. In general, since the washing solvent can be removed by evaporation even at room temperature, drying may be performed by leaving the material at room temperature. In particular, from the viewpoint of efficiently progressing the drying, it is preferable that step (III) includes heat drying. The drying temperature is preferably in the range of 20°C to 400°C, more preferably 50°C to 300°C.

[0097] [7. Optional Process] The nozzle cleaning method may further include any step, such as a step of wiping off the epoxy resin composition before step (I), a step of wiping off the organic cleaning liquid before step (II), or a step of wiping off the organic solvent after step (II).

[0098] [8. Manufacturing method for recycled nozzles] The nozzle cleaning method described above may be implemented as a manufacturing method for producing a recycled nozzle from a used nozzle. A used nozzle refers to a nozzle to which an epoxy resin composition has adhered, and thus may correspond to a nozzle after it has been used to eject an epoxy resin composition. A recycled nozzle refers to a nozzle from which the epoxy resin composition has been removed, making it possible to use the nozzle again to eject a liquid composition such as an epoxy resin composition. Therefore, the nozzle manufacturing method described above can be implemented as a manufacturing method for a recycled nozzle that includes, in this order, a step (I) of cleaning the used nozzle with an organic cleaning liquid and a step (II) of cleaning the used nozzle with a cleaning solvent. [Example]

[0099] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples. In the following description, the units "parts" and "%" that represent amounts are by mass unless otherwise specified. Furthermore, the operations described below were carried out in an environment of room temperature and normal pressure (25°C, 1 atm) unless otherwise specified.

[0100] [Reagent Description] The types of reagents used in the following examples and comparative examples are as follows:

[0101] [Liquid epoxy resin] JER-828EL: Mitsubishi Chemical Corporation, bisphenol A (BPA) liquid epoxy resin, epoxy equivalent weight 186g / eq. ZX-1059: Nippon Steel Chemical & Material Co., Ltd., bisphenol A (BPA) / bisphenol F (BPF) liquid mixed epoxy resin, epoxy equivalent 165g / eq. JER-1001: Mitsubishi Chemical Corporation, bisphenol A (BPA) solid epoxy resin, epoxy equivalent weight 450g / eq.-500g / eq. N-730-A: DIC, bisphenol F (BPF) liquid epoxy resin, epoxy equivalent weight 172g / eq. to 179g / eq.

[0102] [Solid dispersion type latent curing agent] PN-F: Ajinomoto Fine-Techno Co., Ltd., amine adduct type latent hardener MY-24: Ajinomoto Fine-Techno Co., Ltd., amine adduct type latent hardener

[0103] [Thiol compounds] DPMP: SC Organic Chemicals, dipentaerythritol hexakis(3-mercaptopropionate), thiol functional group equivalent 130g / eq.

[0104] [ka]

[0105] [Coloring agent] PV-10MB: Ajinomoto Fine-Techno Co., Inc., carbon black dispersed bisphenol A (BPA) liquid epoxy resin, epoxy equivalent weight 226g / eq.

[0106] [Production Examples 1 to 3. Production of epoxy resin compositions (objects to be cleaned) containing solid-dispersed latent curing agents] Epoxy resin compositions 1 to 3 were produced by mixing the components according to the formulation shown in Table 1. In Table 1, the amount of each component means parts by mass. Specifically, the amounts of epoxy resin and thiol compound shown in Table 1 were weighed into dedicated plastic containers. Then, using a planetary centrifugal mixer (Thinky Corporation, "ARE-310"), the mixture was thoroughly mixed at 2000 rpm for approximately 30 seconds to 1 minute at room temperature (25°C) to obtain resin compositions. The amounts of solid-dispersion latent curing agent and liquid epoxy resin containing carbon black shown in Table 1 were added to the resin composition, and the mixture was thoroughly mixed using the planetary centrifugal mixer at 2000 rpm for approximately 30 seconds to 1 minute at room temperature (25°C). Finally, the mixture was degassed under vacuum (set to zero pressure) at 900 rpm for 2 minutes in an automatic planetary centrifugal mixer (Kyoritsu Seiki Co., Ltd., "HM-200W") to obtain epoxy resin compositions 1 to 3. Carbon black was added to simplify visual inspection.

[0107] [Table 1]

[0108] [Production Examples 4 to 6. Production of liquid resin for cleaning (organic cleaning liquid)] Liquid resins A to C were produced as organic cleaning liquids by mixing the components according to the formulation shown in Table 2. In Table 2, the amount of each component means parts by mass. Specifically, in Production Examples 4 and 5, the amounts of epoxy resin shown in Table 2 were weighed out and placed in dedicated plastic containers. Then, using a planetary centrifugal mixer, Awatori Rentaro ("ARE-310" manufactured by Thinky Corporation), the mixture was thoroughly mixed at 2000 rpm at room temperature (25°C) for approximately 30 seconds to 1 minute to obtain liquid resins A and B. In Production Example 6, the epoxy resin in the amount shown in Table 2 was weighed out into a SUS cup. The resin was then heated and melted using an IH heater and cooled to obtain Liquid Resin C.

[0109] [Table 2]

[0110] [Viscosity evaluation] The viscosities of the epoxy resin compositions 1 to 3 produced in the above-mentioned Production Examples 1 to 3 and the liquid resins A, B and C produced in the above-mentioned Production Examples 4 to 6 were measured by the following method. The temperature of the sample (epoxy resin composition, liquid resin) was kept at 25°C (±2°C), and the viscosity (Pa s) was measured using an E-type viscometer (Toki Sangyo Co., Ltd. "RE-85U" with a 3° × R9.7 rotor) with a sample volume of 0.22 ml and a rotation speed of 20 rpm.

[0111] [Example 1] (1-1. Using the nozzle) The epoxy resin composition 1 produced in Production Example 1 was filled into a syringe (a 10 cc syringe "PSY-10E" manufactured by Musashi Engineering Co., Ltd.). A nozzle (a 0.26 mm inner diameter plastic needle "PN-25G-A" manufactured by Musashi Engineering Co., Ltd.) was attached to the syringe. The syringe was attached to a dispenser, and the epoxy resin composition 1 in the syringe was discharged through the nozzle.

[0112] (1-2. Replacement cleaning with liquid resin) The nozzle was removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. Separately, liquid resin C produced in Production Example 6 was filled into a syringe (a 10 cc syringe "PSY-10E" manufactured by Musashi Engineering Co., Ltd.). The used nozzle was attached to the syringe filled with liquid resin C. The syringe was attached to a dispenser, and liquid resin C was ejected through the used nozzle for 25 seconds at an air pressure of 400 kPa. It was confirmed that the color of the liquid ejected from the nozzle was black immediately after ejection began, but became transparent just before ejection ended.

[0113] (1-3. Ultrasonic cleaning with organic solvents) The nozzle was removed from the syringe and immersed in acetone as an organic solvent and ultrasonically cleaned for 5 minutes.

[0114] (1-4. Drying) The nozzle was removed from the organic solvent, shaken several times to remove the organic solvent from inside the nozzle, and then dried. Drying was carried out by leaving it at room temperature for 30 minutes. Through these operations, a regenerated nozzle was obtained by cleaning the used nozzle.

[0115] (1-5. Evaluation of nozzle clogging) The inside of the regenerated nozzle was visually observed, and the nozzle clogging was evaluated based on the results of the observation according to the following criteria. "◯": No clogging occurred inside the nozzle. "X": Clogging occurred inside the nozzle.

[0116] (1-6.Final judgment) The above operation was performed twice to evaluate the clogging of the two regenerated nozzles. The final judgment was "Good" if no clogging occurred both times, "Good" if clogging occurred once, and "Poor" if clogging occurred both times.

[0117] [Example 2] Nozzle cleaning and evaluation were carried out in the same manner as in Example 1, except that epoxy resin composition 2 produced in Production Example 2 was used instead of epoxy resin composition 1, and liquid resin A produced in Production Example 4 was used instead of liquid resin C.

[0118] [Example 3] Nozzle cleaning and evaluation were carried out in the same manner as in Example 1, except that epoxy resin composition 2 produced in Production Example 2 was used instead of epoxy resin composition 1, and liquid resin B produced in Production Example 5 was used instead of liquid resin C.

[0119] [Example 4] Nozzle cleaning and evaluation were carried out in the same manner as in Example 1, except that epoxy resin composition 2 produced in Production Example 2 was used instead of epoxy resin composition 1.

[0120] [Example 5] The nozzle was cleaned and evaluated in the same manner as in Example 1, except that the organic solvent used in the ultrasonic cleaning was changed to ethyl acetate and the ultrasonic cleaning time was changed to 10 minutes.

[0121] [Example 6] The nozzle was cleaned and evaluated in the same manner as in Example 1, except that the organic solvent used in the ultrasonic cleaning was changed to isopropyl alcohol and the ultrasonic cleaning time was changed to 15 minutes.

[0122] [Example 7] Nozzle cleaning and evaluation were carried out in the same manner as in Example 1, except that epoxy resin composition 3 produced in Production Example 3 was used instead of epoxy resin composition 1.

[0123] [Comparative Example 1] The nozzle was cleaned and evaluated in the same manner as in Example 1, except that replacement cleaning using a liquid resin was not performed. Specifically, epoxy resin composition 1 was discharged through the nozzle in the same manner as in step (1-1) of Example 1, the nozzle was removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. This used nozzle was subjected to ultrasonic cleaning and drying under the same conditions as in steps (1-3) and (1-4) of Example 1, and then evaluated.

[0124] Comparative Example 2 Nozzle cleaning and evaluation were performed in the same manner as in Example 1, except that epoxy resin composition 2 produced in Production Example 2 was used instead of epoxy resin composition 1 and replacement cleaning using a liquid resin was not performed. Specifically, epoxy resin composition 1 was ejected through a nozzle in the same manner as in step (1-1) of Example 1, except that epoxy resin composition 2 was used instead of epoxy resin composition 1. The nozzle was then removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. This used nozzle was then subjected to ultrasonic cleaning and drying under the same conditions as in steps (1-3) and (1-4) of Example 1, and then evaluated.

[0125] Comparative Example 3 Nozzle cleaning and evaluation were performed in the same manner as in Example 1, except that replacement cleaning using a liquid resin was not performed and the ultrasonic cleaning conditions were changed as shown in Table 3. Specifically, epoxy resin composition 1 was discharged through the nozzle in the same manner as in step (1-1) of Example 1, the nozzle was removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. This used nozzle was immersed in ethyl acetate as an organic solvent and ultrasonically cleaned for 10 minutes. The nozzle was then removed from the organic solvent and shaken several times to remove the organic solvent from the inside of the nozzle. It was then left to dry at room temperature for 30 minutes before evaluation.

[0126] Comparative Example 4 Nozzle cleaning and evaluation were performed in the same manner as in Example 1, except that replacement cleaning using a liquid resin was not performed and the ultrasonic cleaning conditions were changed as shown in Table 3. Specifically, epoxy resin composition 1 was discharged through the nozzle in the same manner as in step (1-1) of Example 1, the nozzle was removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. This used nozzle was immersed in isopropyl alcohol as an organic solvent and ultrasonically cleaned for 15 minutes. The nozzle was then removed from the organic solvent and shaken several times to remove the organic solvent from the inside of the nozzle. It was then left to dry at room temperature for 30 minutes before evaluation.

[0127] Comparative Example 5 Nozzle cleaning and evaluation were performed in the same manner as in Example 1, except that epoxy resin composition 3 produced in Production Example 3 was used instead of epoxy resin composition 1 and replacement cleaning using a liquid resin was not performed. Specifically, epoxy resin composition 1 was ejected through a nozzle in the same manner as in step (1-1) of Example 1, except that epoxy resin composition 3 was used instead of epoxy resin composition 1. The nozzle was then removed from the syringe, and dirt on the nozzle connector was wiped off with a cotton swab to obtain a used nozzle. This used nozzle was subjected to ultrasonic cleaning and drying under the same conditions as in steps (1-3) and (1-4) of Example 1, and then evaluated.

[0128] [result] The results of the above Examples and Comparative Examples are shown in the following Table 3. In the following Table 3, the meanings of the abbreviations are as follows. AC: Acetone EA: Ethyl acetate IPA: Isopropyl alcohol

[0129] [Table 3]

[0130] [Discussion of results] In Comparative Examples 1 to 5, cleaning with an organic solvent was performed while the nozzle was filled with an epoxy resin composition containing a solid-dispersion-type latent curing agent, and clogging was confirmed inside the nozzle. On the other hand, in Examples 1 to 7, no clogging occurred inside the nozzle, and no adhesion of foreign matter was observed. From the above results, it was confirmed that the nozzle cleaning method of the present invention can prevent adhesion of the cured epoxy resin composition to the nozzle, and therefore it is possible to clean the nozzle while preventing clogging of the nozzle. [Explanation of symbols]

[0131] 100 nozzles 110 Flow path 120 Inlet 130 Discharge port 140 Connector part 150 Needle part 200 syringes 210 Nozzle mounting part 220 Hollow part 230 outlet 240 Plunger 250 opening 300 Epoxy resin composition

Claims

1. A method for cleaning a nozzle used in applying an epoxy resin composition comprising (A) an epoxy resin and (B) a first solid-dispersion-type latent curing agent, the method comprising: The cleaning method comprises: (I) a step of cleaning the nozzle with a liquid organic substance containing 50% by mass to 100% by mass of a liquid epoxy resin; and a step (II) of washing the nozzle with one or more first organic solvents selected from diethyl ether, pentane, acetone, chloroform, methanol, tetrahydrofuran, diisopropyl ether, hexane, ethyl acetate, ethanol, methyl ethyl ketone, cyclohexane, acetonitrile, isopropyl alcohol, tert-butyl alcohol, 1,2-dimethoxyethane, 1-propanol, heptane, 2-butanol, 1,4-dioxane, isobutyl alcohol, toluene, butanol, o-xylene, dimethylformamide, and dimethyl sulfoxide; in this order; In the liquid organic substance, the amount of the second solid-dispersed latent curing agent (a) activated by the first organic solvent used in the step (II) is 1 mass% or less relative to 100 mass% of the liquid organic substance; the amount of the second organic solvent (b) that activates the first solid-dispersed latent curing agent (B) present in the epoxy resin composition is 0.1% by mass or less relative to 100% by mass of the liquid organic substance.

2. 2. The nozzle cleaning method according to claim 1, wherein the liquid organic substance is a liquid resin.

3. 3. The nozzle cleaning method according to claim 1, wherein the liquid organic substance is a liquid epoxy resin.

4. A method for cleaning a nozzle described in any one of claims 1 to 3, wherein the first organic solvent is selected from the group consisting of acetone, isopropanol, and ethyl acetate.

5. 5. The nozzle cleaning method according to claim 1, wherein the nozzle is a nozzle used to discharge the epoxy resin composition from a syringe containing the epoxy resin composition.

6. 6. The nozzle cleaning method according to claim 1, wherein the nozzle is a nozzle used for discharging the epoxy resin composition in a dispenser equipped with a syringe capable of storing the epoxy resin composition.

7. The nozzle cleaning method according to any one of claims 1 to 6, wherein the first organic solvent used in the step (II) has a boiling point of 200°C or lower.

8. the step (II) includes washing the nozzle with the first organic solvent multiple times; The method for cleaning a nozzle according to any one of claims 1 to 7, wherein at least the final cleaning is carried out with a first organic solvent having a boiling point of 100°C or less.

9. The nozzle cleaning method according to any one of claims 1 to 8, further comprising, after the step (II), a step (III) of drying the nozzle.

10. The nozzle cleaning method according to claim 9 , wherein the step (III) includes heating and drying the nozzle.

11. A method for producing a recycled nozzle from a used nozzle that has been used to apply an epoxy resin composition containing (A) an epoxy resin and (B) a first solid-dispersion-type latent curing agent, the method comprising: (I) a step of cleaning the used nozzle with a liquid organic substance containing 50% by mass to 100% by mass of a liquid epoxy resin; and a step (II) of washing the used nozzle with one or more first organic solvents selected from diethyl ether, pentane, acetone, chloroform, methanol, tetrahydrofuran, diisopropyl ether, hexane, ethyl acetate, ethanol, methyl ethyl ketone, cyclohexane, acetonitrile, isopropyl alcohol, tert-butyl alcohol, 1,2-dimethoxyethane, 1-propanol, heptane, 2-butanol, 1,4-dioxane, isobutyl alcohol, toluene, butanol, o-xylene, dimethylformamide, and dimethyl sulfoxide; in this order, In the liquid organic substance, the amount of the second solid-dispersed latent curing agent (a) activated by the first organic solvent used in the step (II) is 1 mass% or less relative to 100 mass% of the liquid organic substance; the amount of the second organic solvent (b) that activates the first solid-dispersed latent curing agent (B) present in the epoxy resin composition is 0.1% by mass or less relative to 100% by mass of the liquid organic substance.

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