JP2014019810A - Cleaning agents and cleaning methods - Google Patents

Abstract

[PROBLEMS] To not only contain water but also a disadvantage of a detergent containing a dibasic acid ester that is useful for industrial cleaning applications. It is an object of the present invention to provide a cleaning agent that eliminates noticeable stains and discoloration, exhibits and maintains excellent cleaning power, and can stably continue a high degree of finish, and a cleaning method using the same.
A cleaning agent comprising a dibasic acid ester and having a sulfur content of 12 ppm or less.
[Selection figure] None

Description

  The present invention relates to a cleaning agent and a cleaning method.

  The dibasic acid ester has an appropriate dissolving power for various types of dirt (resin, ink, paste, flux, rosin, oil, etc.), and is useful as a component of a wide range of cleaning agents.

  As a detergent containing a dibasic acid ester, not only the dibasic acid ester alone but also a solvent component other than the dibasic acid ester and a composition containing water have been proposed.

  For example, Patent Document 1 describes a screen plate cleaning agent using a combination of a dibasic acid ester and a specific cyclic ester. Further, Patent Document 2 describes a screen plate cleaning agent comprising a combination of a dibasic acid ester, 1,3-dimethyl-2-imidazolidinone, and water. Furthermore, in patent document 3, the cleaning agent by the combination of dibasic acid ester and glycol ether is described. Furthermore, Patent Document 4 describes an ink cleaning composition using a combination of a dibasic acid ester and acetophenone. Furthermore, Patent Document 5 describes a cleaning composition comprising a combination of a dibasic acid ester, a glycol ether, and a hydrocarbon. In addition, Patent Document 6 describes a cleaning composition for a mixing nozzle using only a dibasic acid ester. Moreover, in patent document 7, the cleaning method of the sealing agent discharge nozzle components by the combination of dibasic acid ester and glycol ether is described.

  In the industrial cleaning field, there are a wide variety of materials and dirt on the object to be cleaned, and there are also changes in the material and dirt on the object to be cleaned due to technological advances. In addition, there is an increasing demand for the finished state after cleaning, not just removing dirt, but a stable finish that does not cause changes such as stains or discoloration on the surface of the cleaned object continues. It is demanded.

  For example, in screen printing, as the printing line width increases, the screen mesh used for printing becomes finer, and spots and discoloration that occur on the surface of the screen mesh become more problematic. Further, in order to reduce the distortion of the screen mesh, the material of the screen mesh is changed from a polyester mesh made of resin to a stainless steel mesh and further to a stainless steel mesh plated with nickel. Stain, discoloration on the surface of the stainless steel mesh, and discoloration of the nickel plating slightly change the wettability of the ink and paste, leading to poor printing.

JP 2000-141939 A Japanese Patent Laid-Open No. 7-62396 Japanese Patent Laid-Open No. 6-93292 JP-A-6-93293 JP 2006-342247 A JP 2005-47939 A JP 2010-247123 A

  However, when a high-definition screen plate ink or paste is washed with a detergent containing a dibasic acid ester, there is a problem in that a stain or discoloration is caused on the screen plate, particularly in a detergent containing water. There are also similar problems in flux cleaning and dispenser cleaning.

  Even if no stain or discoloration occurs at the start of use of the cleaning agent, the stain or discoloration may occur during continued use. Even if it does not contain water in the initial stage, water may be contained in the cleaning agent before and during use due to contamination of rinsing water used in the rinsing process after washing, moisture in the outside air, etc. This is because it may be mixed. Therefore, there is also a problem from the viewpoint that a stable finish cannot be continued depending on the cleaning conditions.

  The present invention has been made in view of the above-described problems, and is a cleaning agent that is a defect of a cleaning agent containing a dibasic acid ester that is useful not only when water is not included but also for industrial cleaning applications. Even when water is contained, a cleaning agent that eliminates stains and discoloration that are noticeably generated on the cleaning object after cleaning, exhibits and maintains excellent cleaning power, and can stably maintain a high level of finish. The purpose is to provide a cleaning method.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the above problem can be solved by using a detergent containing a dibasic acid ester and having a sulfur content of a certain concentration or less.
That is, the present invention is as follows.

[1]
A cleaning agent comprising a dibasic acid ester and having a sulfur content of 12 ppm or less.
[2]
The cleaning agent according to item [1], further comprising water.
[3]
The cleaning agent according to [1] or [2] above, further comprising a glycol ether represented by the formula (1).
R ¹ O— (R ² O) _n —R ³ (1)
(In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, R ² is an alkylene group having 2 to 5 carbon atoms, R ³ is hydrogen, and 1 carbon atom. -6 alkyl group or a C3-C6 cycloalkyl group, n shows the integer of 1-4.)
[4]
The cleaning agent according to any one of [1] to [3], wherein the dibasic acid ester is one or more selected from the group consisting of dimethyl adipate, dimethyl glutarate, and dimethyl succinate.
[5]
The cleaning agent according to any one of [1] to [4], wherein the dibasic acid ester includes a mixture of the following (a), (b), and (c).
(A) Dimethyl adipate 1-60 mass%
(B) Dimethyl glutarate 10-80% by mass
(C) Dimethyl succinate 5-40% by mass
[6]
The cleaning agent according to any one of [1] to [5], wherein the content of the dibasic acid ester is 4.99 to 95% by mass.
[7]
The cleaning agent according to any one of [2] to [6], wherein the water content is 0.01 to 30% by mass.
[8]
The cleaning agent according to any one of [3] to [7], wherein the glycol ether content is 4.99 to 95% by mass.
[9]
The cleaning agent according to any one of [1] to [8], which is used for cleaning ink and paste.
[10]
The cleaning agent according to any one of [1] to [8], wherein the cleaning agent is for flux cleaning.
[11]
The cleaning agent according to any one of [1] to [8], which is used for cleaning a dispenser.
[12]
A cleaning method using the cleaning agent according to any one of [1] to [11].

  According to the present invention, not only when water is not contained, but also when water is included, which is a disadvantage of a detergent containing a dibasic acid ester that is useful for industrial cleaning applications, It is possible to realize a cleaning agent that eliminates stains and discoloration that occurs, exhibits and maintains excellent cleaning power, and can stably maintain a high degree of finish, and a simple and stable cleaning method using the same.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible.

〔Washing soap〕
The cleaning agent of this embodiment contains a dibasic acid ester and has a sulfur content of 12 ppm or less.

[Sulfur content]
When the sulfur content is 12 ppm or less, it is possible to suppress stains and generation of the washed product. The sulfur content in the detergent containing the dibasic acid ester is preferably 6 ppm or less, more preferably 2 ppm or less. The lower limit of the sulfur content is not particularly limited, but it is preferably as low as possible, more preferably 0.01 ppm. The sulfur content in the cleaning agent can be detected and measured as sulfate ion by combustion-ion chromatography. In more detail, it can measure by the method as described in an Example.

  As a method for controlling the sulfur content in the cleaning agent to 12 ppm or less, use of a dibasic acid ester from which a sulfur compound contained as an impurity is removed can be mentioned.

[Dibasic acid ester]
Although it does not specifically limit as dibasic acid ester used for this embodiment, Specifically, it is preferable that it is alkyl ester of dibasic acids, such as adipic acid, glutaric acid, and succinic acid. Although it does not specifically limit as a specific example of an alkyl group, Specifically, C1-C6 alkyl, such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl, pentyl, hexyl, cyclohexyl, etc. Groups. Among these, an alkyl group having 4 or less carbon atoms is preferable, and a methyl group is more preferable. The dibasic acid ester is more preferably at least one selected from the group consisting of dimethyl adipate, dimethyl glutarate, and dimethyl succinate. If it is such a dibasic acid ester, it will become the cleaning agent which has the more outstanding cleaning power.

(Sulfur content of dibasic acid ester)
When the sulfur content in the cleaning agent of the present embodiment is derived from a sulfur compound contained as an impurity in the dibasic acid ester, the sulfur content contained in the dibasic acid ester is preferably 20 ppm or less, more preferably Is 15 ppm or less, more preferably 10 ppm or less.

(Purification method)
When a sulfur compound is contained as an impurity in the dibasic acid ester, the sulfur content in the dibasic acid ester can be adjusted to 20 ppm or less by purification using a known purification method. For example, after mixing and stirring a dibasic acid ester and water, the layers are separated and the organic layer is taken out, and the organic layer is distilled, whereby the sulfur content in the dibasic acid ester can be adjusted to 20 ppm or less. . The sulfur content of the dibasic acid ester can be detected and measured as sulfate ion by combustion-ion chromatography.

  In addition, when the dibasic acid ester is a mixture of a plurality of dibasic acid esters, and the composition of the mixture is changed by the above purification operation, the dibasic acid ester is added by adding a simple dibasic acid ester having a low sulfur content. It can be adjusted.

The dibasic acid ester may be used alone or in a mixture, but is more preferably used in a mixture. Specifically, the dibasic acid ester preferably contains a mixture of (a) dimethyl adipate, (b) dimethyl glutarate, and (c) dimethyl succinate. In this case, the contents of (a) to (c) are as follows:
(A) Dimethyl adipate 1-60 mass%
(B) Dimethyl glutarate 10-80% by mass
(C) Dimethyl succinate 5-40% by mass
Is preferred,
(A) Dimethyl adipate 5-50 mass%
(B) Dimethyl glutarate 20-75 mass%
(C) Dimethyl succinate 10-30% by mass
Is more preferred,
(A) Dimethyl adipate 10-40% by mass
(B) Dimethyl glutarate 40-65 mass%
(C) Dimethyl succinate 15-25% by mass
Is more preferable. By being such a mixture, it becomes a cleaning agent having more excellent cleaning power.

  The content of the dibasic acid ester in the cleaning agent is adjusted depending on the cleaning use, but is preferably 4.99 to 95% by mass, more preferably 10 to 80% by mass, and further preferably 30 to 60%. % By mass. By being the said preferable range, it becomes a cleaning agent which has the more outstanding cleaning power.

〔water〕
The cleaning agent of this embodiment preferably contains water for the purpose of improving the solubility of water-soluble soil and eliminating the flash point. The water content is adjusted depending on the cleaning application, but is preferably 0.01 to 30% by mass, more preferably 1 to 25% by mass, and further preferably 5 to 15% by mass. By being the said preferable range, it has the cleaning power which was more excellent with respect to water-soluble stain | pollution | contamination, and also becomes a cleaning agent with a high flash point or a flash point. Even if water is contained in this way, the cleaning agent of the present embodiment enables a high-quality finish that does not cause stains or discoloration on the cleaning object.

[Glycol ether]
Moreover, it is preferable that the cleaning agent of this embodiment contains the glycol ether of Formula (1) in order to improve the detergency against dirt.
R ¹ O— (R ² O) _n —R ³ (1)
(In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, R ² is an alkylene group having 2 to 5 carbon atoms, R ³ is hydrogen, and 1 carbon atom. -6 alkyl group or a C3-C6 cycloalkyl group, n shows the integer of 1-4.)

In formula (1), R ¹ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, Examples include pentyl group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and the like.

R ² is an alkylene group having 2 to 5 carbon atoms, and specific examples include a methylene group, an ethylene group, a propylene group, a butylene group, and a pentylene group.

R ³ is hydrogen, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, specifically, hydrogen, methyl group, ethyl group, propyl group, butyl group, isopropyl group, pentyl Group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and the like.

  Although it does not specifically limit as glycol ether of Formula (1), Specifically, monoalkyl ether, dialkyl ether, monocyclo of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol is used. Examples thereof include alkyl ethers and cycloalkylalkyl diethers. In addition, glycol ether may be used independently or may be used by 2 or more types.

  More specifically, diethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene Examples include glycol monobutyl ether, tripropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, and triethylene glycol dimethyl ether. Of these, diethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, dipropylene glycol monomethyl ether, and dipropylene glycol monopropyl ether are preferably used.

  The content of glycol ether in the cleaning agent is appropriately adjusted depending on the cleaning application, but is preferably 4.99 to 95% by mass, more preferably 20 to 90% by mass, and further preferably 30 to 60% by mass. is there. By being the said preferable range, it becomes a cleaning agent which has the more outstanding cleaning power.

[Other ingredients]
As the other known additives, surfactants, rust inhibitors, stabilizers, antioxidants, and the like can be added to the cleaning agent as necessary. A known surfactant can be used as the surfactant. Such surfactant is not particularly limited, and specific examples include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene-polyoxypropylene alkyl ether, and the like. It is not limited to.

  Although it does not specifically limit as a rust preventive agent, Specifically, a fatty acid, metal soap, amines, dicyclohexylammonium nitrite, diisopropylamine nitrite, dicyclohexylamine caprate, benzotriazole, etc. can be mentioned.

  The stabilizer is not particularly limited. Specifically, 2,5-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis- (6-t- Butylphenol), 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) bropionate, and Antioxidants such as 4,4′-thiobis- (6-t-butylphenol); laurate, myristate, palmitate, stearate, isostearate, oleate, ricinoleate, 2- Mention may be made of heat stabilizers such as ethyl-hexylate, isodecanoate, neodecanoate and calcium benzoate.

  Although it does not specifically limit as antioxidant, Specifically, a hindered phenol type compound, a phosphorus type compound, etc. can be mentioned.

[Production method of cleaning agent]
The cleaning agent of this embodiment can be produced by mixing the above components by a known method.

[Use]
The cleaning agent of this embodiment can be used as a cleaning agent for removing ink and paste adhered to screen printing or the like. The cleaning agent of this embodiment can dissolve and disperse the resin component and solvent component contained in the ink and paste, and can efficiently remove ink and paste stains. The cleaning agent for ink and paste may contain at least one selected from the group consisting of water, glycol ether, and monoester, if necessary. In this case, the preferable ratio of water is 0.01 to 30% by mass, the preferable ratio of glycol ether is 4.99 to 95% by mass, and the preferable ratio of monoester is 40 to 70% by mass. The monoester is not particularly limited, and specific examples include γ-butyrolactone, 3-methoxy-3-methyl acetate, glycol ether acetate, acetic acid alkyl ester, and lactate alkyl ester.

  The cleaning agent of the present embodiment can be used as a cleaning agent for removing flux used for soldering attached to an electronic component. The cleaning agent of this embodiment can dissolve and disperse the rosin component contained in the flux, and can efficiently remove the dirt on the flux. The cleaning agent for flux may contain at least one selected from the group consisting of water, glycol ethers, and monoesters as necessary. In this case, the preferable ratio of water is 0.01 to 30% by mass, the preferable ratio of glycol ether is 4,99 to 95% by mass, and the preferable ratio of monoester is 40 to 70% by mass. Examples of the monoester include those described above.

  The cleaning agent of this embodiment can be used as a cleaning agent for removing a resin attached to a dispenser that mixes and discharges a liquid resin such as an epoxy resin, a urethane resin, or a silicon resin. The cleaning agent of this embodiment can dissolve and disperse a liquid resin such as an epoxy resin, a urethane resin, and a silicone resin, and can efficiently remove resin stains. The cleaning agent for the dispenser may contain at least one selected from the group consisting of glycol ethers, monoesters, hydrocarbons, and amide compounds, if necessary. In this case, the preferred proportion of glycol ether is 4.99 to 95 mass%, the preferred proportion of monoester is 40 to 70 mass%, the preferred proportion of hydrocarbon is 10 to 40 mass%, the preferred proportion of amide compound As, it is 10-40 mass%. Examples of the monoester include the same ones as described above. Although it does not specifically limit as hydrocarbon, Specifically, unsaturated hydrocarbons, such as decane, dodecane, and tetradecane; Unsaturated hydrocarbons, such as 1-decene, 1-dodecene, and 1-tetradecene, are mentioned. Further, the amide compound is not particularly limited, and specifically, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N, N-dialkyl -3-methoxypropionamide, N, N-dialkyl-3-butoxypropionamide and the like.

[Cleaning method]
The cleaning method of this embodiment uses the above cleaning agent. A cleaning method using the cleaning agent of this embodiment will be described below. In addition, the washing | cleaning method using the cleaning agent of this embodiment can be performed using the well-known cleaning tool and washing machine.

  For example, a cleaning tank equipped with an ultrasonic oscillator is filled with a cleaning solution, a screen plate, a metal mask plate, an electronic component, a dispenser component are immersed, ultrasonically cleaned, and after cleaning, dried by air blow or hot air. It is done. If necessary, water rinsing may be added in a rinsing tank provided with an ultrasonic oscillator between washing and drying.

Further, instead of ultrasonic cleaning, there is also spray cleaning in which cleaning liquid is pumped up and sprayed onto a screen plate, a metal mask plate, an electronic component, or a dispenser component.
In the case of dispenser cleaning, there is a method in which a cleaning liquid is injected into the resin mixing tank, and the resin mixing tank is cleaned by stirring with a stirring blade of the dispenser itself, and after cleaning, the cleaning liquid is discharged from the resin mixing tank. .

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited at all by the following examples.

[Examples 1-36 and Comparative Examples 1-36]
Dibasic acid esters 1-36 shown in Table 1 were prepared. In Table 1, dimethyl adipate (Invista Japan Co., Ltd .; DBE-6) is DMA, dimethyl glutarate (Invista Japan Co., Ltd .; DBE-5) is DMG, dimethyl succinate (Invista Japan Co., Ltd .; DBE-) 4) is abbreviated as DMS. Adjustment was carried out by appropriately measuring DMA, DMG and DMS alone and a mixture of DMA, DMG and DMS (manufactured by Invista Japan Co., Ltd .; DBE). The numerical value of each component in Table 1 indicates mass% with respect to the entire dibasic acid ester.

  Using dibasic acid esters 1 to 36, cleaning agents A1 to X1 shown in Table 2, cleaning agents A2 to X2 shown in Table 3, and cleaning agents A3 to X3 shown in Table 4 were prepared.

  In Table 2, diethylene glycol butyl ether (Nippon Emulsifier Co., Ltd .; BDG) was abbreviated as BDG. Among the numerical values of each component in Table 2, the sulfur content indicates the content (ppm) with respect to the entire cleaning agent, and the values of the other components indicate mass% with respect to the entire cleaning agent.

  In Table 3, dipropylene glycol methyl ether (Dow Chemical Japan Co., Ltd .; Dawanol DPM) was abbreviated as DPM. Among the numerical values of each component in Table 3, the sulfur content indicates the content (ppm) with respect to the entire cleaning agent, and the values of the other components indicate mass% with respect to the entire cleaning agent.

  In Table 4, dipropylene glycol propyl ether (Dow Chemical Japan Co., Ltd .; Dawanol DPnP) was abbreviated as DPP. Among the numerical values of each component in Table 4, the sulfur content indicates the content (ppm) with respect to the entire cleaning agent, and the values of the other components indicate mass% with respect to the entire cleaning agent.

  The following tests (1) and (2) were performed using the cleaning agents A1 to X1, and the results are summarized in Table 5. The following tests (1) and (3) were performed using cleaning agents A2 to X2, and the results are summarized in Table 6. The following tests (1) and (4) were performed using cleaning agents A3 to X3, and the results are summarized in Table 7.

[Measurement method of sulfur content]
The sulfur content in the detergent and in the dibasic acid ester was detected and measured as sulfate ion by combustion-ion chromatography.

(1) Stain, Discoloration Test The cleaning agents shown in Table 2, Table 3, and Table 4 were applied to a 400-mesh stainless steel nickel plating mesh for screen plates, and dried with hot air at 80 ° C. The mesh surface after drying was visually observed, and the appearance change of the mesh surface was determined according to the following criteria. The distinction between spots and discoloration was determined by wiping the appearance-changing portion with ethanol and erasing it when it disappeared, and when it remained as discoloration.
◎: No stain ◎: No discoloration ○: Almost no discoloration ○: Almost no discoloration ×: Obvious discoloration ×: Clear discoloration

(2) Detergency; flux cleaning test A glass epoxy substrate on which about 0.1 g of rosin (manufactured by Wako Pure Chemical Industries, Ltd .; rosin), which is a flux component, was melt-coated was immersed in the cleaning agent shown in Table 2. During immersion, ultrasonic cleaning was performed for 5 minutes under conditions of a frequency of 40 kHz and a temperature of 50 ° C., and then ultrasonic finishing cleaning was performed for 1 minute. Thereafter, the liquid was cut off by air blow, the rosin residue on the substrate surface after drying was visually observed, and the cleaning property was determined according to the following criteria.
◎: No rosin residue ○: Almost no rosin residue ×: Clearly rosin residue

(3) Detergency: Ink and paste cleaning test About 0.1 g of ink (manufactured by Taiyo Ink; S-100Y) was attached to a 200 mesh stainless steel mesh and immersed in the cleaning agents shown in Table 3. During immersion, ultrasonic cleaning was performed for 5 minutes under the conditions of a frequency of 40 kHz and a temperature of 35 ° C., followed by ultrasonic finishing cleaning for 1 minute. Thereafter, the liquid was cut by air blow, and the ink residue on the mesh surface after drying for 10 minutes with hot air at 80 ° C. was visually observed, and the detergency was determined according to the following criteria.
◎: No ink residue ○: Almost no ink residue ×: Clearly ink residue

(4) Detergency: Dispenser cleaning test A sealant (manufactured by Kyoritsu Chemical Industry Co., Ltd .; thermosetting sealant Worldlock 780P) was applied to a dispenser nozzle having an inner diameter of 0.3 mm and immersed in the cleaning agents shown in Table 4. . During immersion, ultrasonic cleaning is performed for 30 minutes at a frequency of 28 kHz and a temperature of 30 to 40 ° C., and then ultrasonic finishing cleaning is performed for 30 minutes. Then, the liquid is cut off by air blow, and the sealant residue of the nozzle after drying is visually observed. Observing and judging the cleaning properties according to the following criteria.
◎: No sealant residue ○: Almost no sealant residue ×: Clearly sealant residue

  The cleaning agent and cleaning method of the present invention are used for industrial cleaning of metal parts, plastic parts, glass parts, screen plates, metal masks, resin liquid discharge dispenser parts, electronic parts, electronic circuit boards and the like. It is suitable as a cleaning method.

Claims (12)

  A cleaning agent comprising a dibasic acid ester and having a sulfur content of 12 ppm or less.   The cleaning agent according to claim 1, further comprising water. The cleaning agent according to claim 1 or 2, further comprising a glycol ether represented by the formula (1).
R ¹ O— (R ² O) _n —R ³ (1)
(In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, R ² is an alkylene group having 2 to 5 carbon atoms, R ³ is hydrogen, and 1 carbon atom. -6 alkyl group or a C3-C6 cycloalkyl group, n shows the integer of 1-4.)   The cleaning agent according to any one of claims 1 to 3, wherein the dibasic acid ester is at least one selected from the group consisting of dimethyl adipate, dimethyl glutarate, and dimethyl succinate. The cleaning agent according to any one of claims 1 to 4, wherein the dibasic acid ester comprises a mixture of the following (a), (b), and (c).
(A) Dimethyl adipate 1-60 mass%
(B) Dimethyl glutarate 10-80% by mass
(C) Dimethyl succinate 5-40% by mass   The cleaning agent according to any one of claims 1 to 5, wherein a content of the dibasic acid ester is 4.99 to 95% by mass.   The cleaning agent according to any one of claims 2 to 6, wherein the water content is 0.01 to 30% by mass.   The cleaning agent according to any one of claims 3 to 7, wherein a content of the glycol ether is 4.99 to 95% by mass.   The cleaning agent according to any one of claims 1 to 8, which is used for cleaning ink and paste.   The cleaning agent according to any one of claims 1 to 8, which is used for cleaning flux.   The cleaning agent according to any one of claims 1 to 8, which is used for cleaning a dispenser.   The cleaning method using the cleaning agent of any one of Claims 1-11.