JP4421322B2 - Cleaning method for goods - Google Patents

Description

  The present invention relates to a method for removing an organic EL material from an article to which an organic EL element material such as a metal mask used in manufacturing an organic electroluminescence element (hereinafter also simply referred to as an organic EL element) is attached.

  The organic EL element is considered to be promising for use as a solid light-emitting and inexpensive large-area full-color display element, and is actively researched. In general, an organic EL element is formed by laminating an anode electrode (ITO), a hole transport layer, an organic layer (light emitting layer), an electron transport layer, and a cathode electrode in this order on a transparent substrate such as a glass plate, and a sealing can on the surface. The arrangement is arranged. The organic layer (light emitting layer), the hole transport layer, and the electron transport layer (hereinafter also simply referred to as an organic layer or the like) contain an organic EL element material. Examples of the organic EL element material include copper phthalocyanine (CuPc) and starburst. Low molecular weight materials such as (star-burst) molecules and high molecular weight materials such as poly (p-phenylene vinylene) (PPV) and polyaniline (PANI) are known.

  In the manufacturing process of an organic EL element using a low molecular material as the organic EL material, the organic layer and the like are formed on the substrate on which the anode electrode layer and, if necessary, the hole transport layer and the organic layer are formed. This is done by vacuum deposition of the material. When an organic layer or the like is formed by vacuum deposition, it is necessary to perform patterning for each pixel in order to display each color or to control unnecessary light emission. A metal mask having slits is used for this patterning (see Patent Documents 1 and 2).

  By the way, when an organic layer etc. are formed by the above vapor deposition methods, organic EL element material adheres to the surface of a metal mask. If the metal mask to which the organic EL element material is adhered is used continuously, the metal mask itself is deformed or the slit is blocked by the deposited organic EL element material, so that highly accurate patterning cannot be performed. For this reason, in order to repeatedly use the metal mask, it is necessary to periodically remove the organic EL material adhering to the surface by cleaning the metal mask. As a cleaning method at this time, a method of manually wiping with an organic solvent, a method of using a supercritical fluid, and the like are known (see Patent Document 3). In the former method, a halogen-based organic solvent such as methylene chloride is often used as the organic solvent because of its high detergency. In addition, when the organic layer (light emitting layer) is formed by an ink jet method, although not cleaning the metal mask, water, alcohol, and a solvent (specifically, cyclohexylbenzene, dihydrobenzofuran) are applied to the nozzle to which the organic EL element material is attached. , Trimethylbenzene, tetramethylbenzene, etc.) are sequentially passed through and washed (see Patent Document 4).

JP 2003-332057 A JP 2003-297666 A JP 2003-305421 A JP 2003-182095 A

  Regarding the cleaning of the metal mask to which the organic EL element material is adhered, the above-described method using a supercritical fluid has the advantage that the organic EL element material can be recycled, but not only a pressure device is required, There are problems in terms of cleaning efficiency and operability.

  The method using the cleaning agent is an industrially advantageous method as can be seen from the fact that it is possible to build an automatic system and is adopted in many fields. However, in this method, the use of a halogen-based organic medium or a benzene derivative is a problem from the viewpoint of environmental problems and safety to the human body. Therefore, in a method using a cleaning agent, it is necessary to find a cleaning agent that does not use these organic solvents and has a high cleaning power for the organic EL element material.

  Accordingly, an object of the present invention is to provide a method for efficiently removing an organic EL material from an article to which an organic EL element material such as a metal mask is attached, by finding a cleaning agent that satisfies such requirements.

  In order to solve the above-mentioned problems, the present inventors examined the cleaning power of many cleaning agents for organic EL materials and examined the cleanliness of the metal mask after cleaning. As a result, (i) alkylene glycol alkyl ether or its ester derivative has higher detergency for organic EL materials than alcohol and other hydrocarbon solvents, and (ii) the detergent contains water or rinses with water. In such a case, a hydroxide or an oxide is formed on the surface of the metal mask, and this peels off due to friction between the metal mask and the base when aligning the metal mask when manufacturing an organic EL element. (Iii) When the cleaning agent contains water-soluble non-volatile components such as inorganic salts, these components remain as residues on the metal mask surface without water rinsing. As in the case of (ii), it has been found that it may cause contamination, and the present invention has been completed.

That is, the first aspect of the present invention cleans an article to which an organic electroluminescent element material is adhered, using a cleaning agent mainly composed of dipropylene glycol monomethyl ether and substantially free of water and a water-soluble nonvolatile additive. This is a method for cleaning an article, characterized in that the organic EL element material adhering to the article is removed. Here, “main component” means a component having the highest content, and the cleaning agent includes a case where the cleaning agent is composed of a single component (this is the same in the third invention described later). ).

  The second aspect of the present invention provides an organic EL element material on a portion of the substrate surface not covered with a metal mask by bringing a substrate whose surface is covered with a metal mask into contact with the vapor of the organic EL element material. An organic EL element material that adheres to the surface of a metal mask in a method of manufacturing an organic EL element that includes a step of vapor deposition and that removes the organic EL element material that adheres to the surface of the metal mask in the process and reuses the metal mask The method for removing water is the cleaning method of the present invention.

The third aspect of the present invention is a cleaning agent for removing an organic EL element material comprising a liquid mainly composed of dipropylene glycol monomethyl ether and substantially free of water and a water-soluble nonvolatile additive.

  According to the cleaning method of the present invention, the organic EL element material attached to an article such as a metal mask can be efficiently removed. In addition, since the cleaning agent of the present invention used at this time does not substantially contain water and water-soluble nonvolatile additives, a clean surface can be obtained without water rinsing. For this reason, the oxide etc. which become a contaminant at the time of organic electroluminescent element manufacture, and a residue do not adhere to the metal mask after washing | cleaning.

In the cleaning method of the present invention, an article to which the organic EL element material is adhered is washed to remove the organic EL element material to which the article is adhered. Here, the organic EL element material means a hole injecting material, a light emitting material, and an electron injecting material used when manufacturing the organic EL element. In general, low molecular weight and high molecular weight materials are known as organic EL element materials, but from the viewpoint of the effect of the method of the present invention (particularly the effect of high removability by the cleaning agent of the present invention), The organic EL element material to be removed is preferably a low molecular material. As the low molecular weight organic EL material, any material that is used as a material deposited on a substrate by a vapor deposition method in the course of manufacturing an organic EL element can be used without any limitation. As an example of such an organic EL material, as a hole injection material, a benzidine type material such as 2Me-TPD and α-NPD, a starburst type amine such as m-MTDATA, and a multimer of benzidine type amine (TPTE). ), Copper phthalocyanine (CuPc), those having a fluorene group such as FTPD, spiro-TPD, oligomers of cycloalkylene amine (OTPAC), and the like. Examples of the light emitting material include DPVBi, Alq ₃ , Bebq ₂ , Comuarin 6, Q, NMQ, Rubrene, DCM-2, TMS-SiPc, and the like. Furthermore, examples of the electron injecting material include ZnPBT, PBD, TAZ and the like. Specific structures of these materials are described in, for example, Toshio Tomita, “Development Trend of Organic EL Materials” (“Electronic Materials”, December 1999, pages 39-44).

  Further, the article to which the organic EL element material adheres is not particularly limited, and is used in the manufacturing process of the organic EL element material or the manufacturing process of the organic EL element, and the organic EL element material may adhere in the process. Some instruments, jigs, devices, products, etc. Among these, a metal mask to which a large amount of organic EL element material adheres has a great merit in applying the cleaning method of the present invention. As the metal mask, a known mask used in the organic EL element material manufacturing process is used without any limitation. Such a metal mask is made of a metal sheet having a thickness of 10 to 1000 μm having slits and windows as described in, for example, Japanese Patent Application Laid-Open Nos. 2004-39628 and 2003-332057. As a material for the metal mask, stainless steel, invar alloy, Ni, Ni alloy or the like is usually used.

  In the cleaning method of the present invention, a cleaning agent (cleaning agent of the present invention) comprising a liquid mainly containing alkylene glycol alkyl ether and / or an ester derivative thereof and substantially free of water and water-soluble nonvolatile additives is used. Then, the article to which the organic EL element material is attached is washed to remove the organic EL element material attached to the article. By using such a cleaning agent, it is possible to cleanly remove the organic EL material without adhering to the surface of the article an oxide, hydroxide, or cleaning residue that becomes a contaminant during the manufacture of the organic EL element.

  Hereinafter, the cleaning agent of the present invention and a method of cleaning an object to be cleaned such as a metal mask by the cleaning method of the present invention using the cleaning agent will be described.

  The cleaning agent of the present invention is a cleaning agent comprising a liquid mainly comprising an alkylene glycol alkyl ether and / or an ester derivative thereof, and substantially free of water and water-soluble non-volatile additives. The cleaning agent is not particularly limited as long as it is a cleaning agent used for removing the organic EL element material adhering to the object to be cleaned. Here, “substantially not containing water” means that water is not actively added unless it is inevitably mixed, and more specifically, the water content is 1% by weight or less, preferably Means 0.1% by weight or less. Further, substantially not containing water-soluble non-volatile additives means that water-soluble non-volatile components such as surfactants and salts are not positively added unless inevitably mixed. Specifically, it means that the content of the water-soluble nonvolatile component is 0.001 g / ml or less, preferably 0.0005 g / ml or less in terms of the evaporation residue defined in JIS-K0067.

  Alkylene glycol alkyl ethers and / or ester derivatives thereof are well-known as components of so-called aqueous detergents or semi-aqueous detergents, and detergents containing these components are used by being mixed with water, and water rinses. It is generally used with a process. Further, in order to enhance the detergency, water-soluble nonvolatile components such as fatty acid salts are often added. The present invention eliminates the need for water rinsing by not containing a water-soluble nonvolatile component, and does not normally use alkylene glycol alkyl ethers and / or ester derivatives thereof. Used as a cleaning agent that does not clean the organic EL element, and has been found to have a high detergency for the organic EL element material.

  Examples of alkylene glycol alkyl ethers and / or ester derivatives thereof that can be suitably used in the present invention include water such as dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monopropyl ether acetate, and butylene glycol monopropyl ether. Insoluble water-soluble alkylene glycol monoalkyl ether or its ester derivative, ethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc. it can. As the alkylene glycol alkyl ether and / or ester derivative thereof in the cleaning agent of the present invention, the solubility of water at 25 ° C. (alkylene glycol alkyl ether or ester derivative thereof at 25 ° C. from the viewpoint of high detergency to the organic EL device material) It is preferable to use those which are 30% by weight or more, particularly those which are miscible with respect to water. Specific examples of such alkylene glycol alkyl ethers and ester derivatives thereof include dipropylene glycol monomethyl ether.

  In addition, the cleaning agent of the present invention is preferably composed of a single alkylene glycol alkyl ether and / or an ester derivative thereof in consideration of the recyclability of the waste liquid, but a plurality of types of alkylene glycol alkyl ethers and / or esters thereof. A mixture of derivatives may be used. Moreover, you may contain organic solvents other than alkylene glycol alkyl ether and / or its ester derivative. Examples of organic solvents that can be used at this time include pyrrolidone compounds such as N-methylpyrrolidone and N-ethylpyrrolidone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, and the like. An arbitrary mixture of two or more types can be mentioned. The content of these organic solvents is preferably 0 to 60% by weight, particularly preferably 0 to 25% by weight, from the viewpoint of detergency.

  The method for removing the organic EL element material adhering to the surface of the article using the cleaning agent of the present invention is not particularly limited except that the cleaning agent of the present invention is used as the cleaning agent. There are known cleaning methods such as a method of immersing an article and irradiating ultrasonic waves, a method of immersing an object to be cleaned in a flowing cleaning agent such as a jet, and a method of spraying a cleaning agent on the object to be cleaned by spraying. Can be used without restriction.

  In the cleaning method of the present invention, after the cleaning as described above, the drying can be performed as it is. However, since the drying property of the cleaning agent of the present invention is not necessarily good, the organic solvent that dissolves the cleaning liquid of the present invention is used. It is preferable to carry out drying after rinsing with a rinsing liquid comprising a solvent. However, when the rinse liquid contains water, there is a problem of corrosion of the object to be cleaned (when the object to be cleaned is a metal product, formation of metal hydroxide or metal oxide). It is preferable that it is not substantially contained (in other words, the cleaning agent of the present invention is preferably used as a non-aqueous cleaning agent). Here, dissolving the cleaning solution means that the amount of the cleaning agent dissolved in the rinsing solution 1 (l) at 25 ° C. is 10 g or more. As the rinsing liquid, it is preferable to use an organic solvent having a boiling point of 50 to 100 ° C. from the viewpoint of drying properties.

  Examples of organic solvents that can be suitably used as the rinsing liquid in the present invention include alcohols such as methanol, ethyl alcohol, and isopropyl alcohol; ketones such as acetone; chlorinated solvents such as dichloromethane; 1,1,1,3 , 3,4,4-heptafluorobutane, 1,1,1,2,4,4,4-heptafluorobutane, 1,1,1,2,4,4,4-heptafluoro-2- (tri Fluoromethyl) butane, 1,1,2,2,3,3,4,4-octafluoropentane, 1,1,1,2,2,5,5,6,6,6-decafluorohexane, , 1,1,2,2,3,3,4,4-nonafluorohexane and other hydrofluorocarbons (HFCs): 1-chloro-1,2,2-trifluoroethyl methyl ether, 1,1,1 , 2,3,3- Such as oxafluoropropyl methyl ether, 1,1-difluoroethyl ethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,1,2,3,3-hexafluoropropyl n-propyl ether, etc. Fluorinated solvents such as hydrofluoroether (HFE) can be mentioned. Among these, it is preferable to use isopropyl alcohol, HFC or HFE for the reason that the liquid replacement property and the handleability are good. In particular, since HFC and HFE are nonflammable, it is preferable to use HFC and / or HFE from the viewpoint of safety.

  The rinsing method in the rinsing process is not particularly limited. For example, a known method such as a method of immersing an object to be cleaned in a rinsing liquid and irradiating ultrasonic waves, a method of immersing an object to be cleaned in a rinsing liquid having a flow such as a jet. It can carry out more suitably.

  The method of removing the rinsing liquid by drying after rinsing is not particularly limited, but it is preferable to carry out by steam drying using the rinsing liquid used in the rinsing step for the purpose of maintaining cleanliness such as elimination of liquid bleeding. is there. Such steam drying can be suitably performed using a steam drying apparatus as shown in FIG. A steam drying apparatus 1 shown in FIG. 1 includes a tank having a cooling pipe 2 at an upper portion, and a boiling liquid 3 having the same composition as the rinse liquid is stored therein. The boiling liquid 3 is kept in a boiling state by heating from an external heat source (not shown), and a vapor layer 4 is formed in the tank below the cooling pipe 2. If an object 5 having a temperature lower than the vapor temperature is placed in the vapor layer 4, the vapor condenses on the surface of the object to be cleaned, but the temperature of the object to be cleaned rises, and finally the temperature of the object to be cleaned is equal to the vapor temperature. At that time, the object can be dried by taking it out of the tank.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not limited to these Examples.

In addition, the symbol of the compound used by an Example and a comparative example is shown below.
[Alkylene glycol alkylene ethers]
DPM: Dipropylene glycol monomethyl ether DPP: Dipropylene glycol monopropyl ether PB: Propylene glycol monobutyl ether DDE: Diethylene glycol diethyl ether DMP: Diethylene glycol methyl iso-propyl ether [other solvents]
NMP: N-methylpyrrolidone [water-soluble non-volatile additive]
EAC: capric acid monoethanolamine salt [alcohols]
IPA: isopropyl alcohol MeOH: methanol Example 1
As a sample (object to be cleaned), a 50 mm square nickel-plated metal piece coated with an organic EL element material (using Alq ₃ ) by vacuum deposition was prepared, and after washing this sample with a cleaning agent comprising DPM, Rinse with IPA and further steam drying with IPA. Washing was performed by immersing the sample in DPM (1000 ml) having a liquid temperature of 50 ° C. and irradiating with ultrasonic waves for 10 minutes. Subsequently, in order to evaluate detergency, the amount of organic EL remaining in the dried sample was measured as follows. That is, after extracting the organic EL element material adhering to the dried sample surface using 50 ml of dichloromethane, which is a chlorinated solvent, the concentration of the organic EL contained in the extract was measured by liquid chromatography. As a result, the concentration of the organic EL element material was 0.05 ppm, and it was confirmed that the cleaning property of this example was very good.

Example 2
The samples were washed and evaluated for washability in the same manner as in Example 1, except that washing with DPM was performed in two stages, and rinsing was performed and drying was performed using warm air of 80 ° C. after washing. The results are shown in Table 1. Although the detergency was good, drying took a long time. The “detergency evaluation” in Table 1 indicates the relative concentration of the organic EL element material contained in the extract when extracted with dichloromethane as 1 in Example 1.

Example 3 and Comparative Examples 8-11
The sample was washed, dried and dried in the same manner as in Example 1 except that the cleaning agent of the present invention having the composition shown in Table 1 was used and dried using hot air of 80 ° C. without rinsing after washing. Evaluation was performed. The results are shown in Table 1.

Comparative Examples 1-7
The sample was washed, dried and evaluated after drying in the same manner as in Example 1 except that the detergent having the composition shown in Table 1 was used. The results are shown in Table 1.

This figure is a sectional view of a typical steam drying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steam dryer 2 ... Cooling pipe 3 ... Boiling liquid (rinsing liquid)
4 ... Steam layer 5 ... Object to be cleaned

Claims (3)

By washing an article to which the organic electroluminescent element material is adhered using a cleaning agent mainly composed of dipropylene glycol monomethyl ether and substantially free of water and a water-soluble nonvolatile additive, A method for cleaning an article, comprising removing a luminescent element material. Depositing an organic electroluminescent device material on a portion of the substrate surface not covered with a metal mask by contacting a substrate partially coated with a metal mask with a vapor of the organic electroluminescent device material, and In the manufacturing method of an organic electroluminescence element that removes the organic electroluminescence element material attached to the surface of the metal mask in the process and reuses the metal mask,
The method according to claim 1 , wherein the method of removing the organic electroluminescence element material attached to the surface of the metal mask is the method according to claim 1 . A cleaning agent for removing an organic electroluminescent element material comprising a liquid mainly composed of dipropylene glycol monomethyl ether and substantially free of water and a water-soluble nonvolatile additive.

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