Composition for cleaning organic electroluminescence material

Abstract

A composition for cleaning organic electroluminescent materials is disclosed, said composition comprising a first solvent selected from amide-based solvents, urea-based solvents, and combinations thereof; and a second solvent which is an aromatic alcohol-based solvent, provided that said amide-based solvent is not N-methyl-2-pyrrolidone.

Description

Technology Field

[0001] The present disclosure relates to a composition for cleaning organic electroluminescence (EL) materials. Background Technology

[0002] Organic electroluminescent materials are polymer materials that have fluorescent pigments or fluorescent properties and emit light when electricity is passed through them. Organic electroluminescent materials are used in various technological fields that generate light, and an example of this is a display equipped with an organic electroluminescent device.

[0003] Generally, organic light-emitting diodes (OLEDs) consist of a multilayer structure of organic materials. For example, an OLED is composed of a structure such as an anode, a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, an electron injection layer, and a cathode, and various organic materials necessary for light emission are used in the hole injection layer, hole transport layer, emissive layer, electron transport layer, and electron injection layer. OLEDs can be formed by methods such as the deposition of organic materials, and a mask is used during this deposition process. From the perspective of improving the performance or reducing costs of the OLED, the step of effectively cleaning the organic light-emitting material from the mask is important.

[0004] N-methyl-2-pyrrolidone (NMP) is generally used as a cleaning solvent for organic electroluminescent materials. Although NMP is used to remove polymers or organic materials during semiconductor and display processes, it is classified as a reproductive toxicity Class 1B substance due to evidence from animal studies suggesting adverse effects on human sexual function, reproductive capacity, and development. Based on reproductive toxicity data, the European Chemicals Agency is attempting to restrict its use, such as by proposing to the European Union that NMP be added to the list of substances requiring authorization. Domestically, there is also active consideration of restricting the use of NMP or using more environmentally friendly solvents.

[0005] Accordingly, there is a continuing demand for cleaning solutions for organic electroluminescent materials that have low toxicity and excellent cleaning power. Against this backdrop, the inventors have made diligent research efforts to develop an eco-friendly cleaning solution, and as a result, have completed the present disclosure. Prior art literature

[0006] Korean Patent Publication No. 10-2013-0068571 (June 26, 2013) The problem to be solved

[0007] The main object of the present disclosure is to provide an organic electroluminescent cleaning composition having excellent cleaning power without containing N-methyl-2-pyrrolidone. means of solving the problem

[0008] As one embodiment for achieving the above objective, the present disclosure provides a composition for cleaning organic electroluminescent materials, said composition, said composition,

[0009] A first solvent selected from amide-based solvents, urea-based solvents, and combinations thereof; and

[0010] It includes a second solvent which is an aromatic alcohol-based solvent, and

[0011] However, the above amide-based solvent is not N-methyl-2-pyrrolidone. Specific details for implementing the invention

[0012] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0013] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0014] It is understood that the term “about” refers to a range of numbers that a person skilled in the art would consider equivalent to the stated value in terms of achieving the same function or result. When the term “about” is used with a number or value, the term “about” refers to ±20% of the number or value, primarily ±10% of the number or value, often ±5% of the number or value, or ±2% of the number or value. In some modalities, the term “about” may refer to the number or value itself.

[0015] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the description in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0017] Throughout this specification, "%" used to indicate the concentration of a particular substance is (weight / weight) % for solid / solid, (weight / volume) % for solid / liquid, and (volume / volume) % for liquid / liquid, unless otherwise noted.

[0019] In terms of improving the performance or reducing costs of organic electroluminescent devices, a step to effectively clean organic electroluminescent materials from a mask is necessary. At this time, NMP is used to clean organic electroluminescent materials, but according to the Chemical Substances Information Processing System under the Ministry of Environment, NMP is a toxic substance classified as reproductive toxicity 1B and specific target organ toxicity-single exposure 3.

[0021] The present disclosure solves the problems of the prior art by providing a novel composition for cleaning organic electroluminescent materials that does not contain NMP, a toxic substance. The present disclosure provides a cleaning solution for organic electroluminescent materials that has low toxicity and excellent cleaning power.

[0023] In one embodiment for this purpose, the present disclosure provides a composition for cleaning organic electroluminescent materials, said composition

[0024] A first solvent selected from amide-based solvents, urea-based solvents, and combinations thereof; and

[0025] It includes a second solvent which is an aromatic alcohol-based solvent, and

[0026] However, the above amide-based solvent is not N-methyl-2-pyrrolidone.

[0028] According to one embodiment, the amide solvent is a linear amide solvent, a cyclic amide solvent (e.g., a pyrrolidone solvent), or a combination thereof. Specifically, the amide solvent is selected from the group consisting of N,N-dimethylacetamide, N,N-dimethylpropionamide, N,N-diethylformamide, N,N-diethylacetamide, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone, and combinations thereof. Preferably, the amide solvent is N-ethyl-2-pyrrolidone or N,N-dimethylpropionamide.

[0030] According to one embodiment, the urea-based solvent is selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N,N-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diethylurea, and combinations thereof. Preferably, the urea-based solvent is 1,3-dimethyl-2-imidazolidinone.

[0032] According to one embodiment, the aromatic alcohol-based solvent is selected from the group consisting of benzyl alcohol, 2-phenylethanol, 4-cumylphenol, and combinations thereof. Preferably, the aromatic alcohol-based solvent is benzyl alcohol.

[0034] According to one embodiment, the first solvent is about 80% to about 99% by weight of the composition for cleaning organic electroluminescent materials. Preferably, the first solvent is about 85% to about 97% by weight of the composition for cleaning organic electroluminescent materials.

[0036] According to one embodiment, the second solvent is about 1% to about 20% by weight of the composition for cleaning organic electroluminescent materials. Preferably, the second solvent is about 3% to about 15% by weight of the composition for cleaning organic electroluminescent materials.

[0038] According to one embodiment, the first solvent may include a combination of an amide-based solvent and a urea-based solvent.

[0040] In one embodiment, the first solvent comprises a combination of an amide-based solvent and a urea-based solvent, the amide-based solvent is about 60% by weight to about 95% by weight based on the total weight of the first solvent, and the urea-based solvent is about 5% by weight to about 40% by weight based on the total weight of the first solvent. Preferably, the amide-based solvent is about 60% by weight to about 90% by weight based on the total weight of the first solvent, and the urea-based solvent is about 10% by weight to about 40% by weight based on the total weight of the first solvent.

[0042] In one embodiment, the composition for cleaning organic electroluminescent materials according to the present disclosure may be used for cleaning a mask. In one embodiment, the cleaning composition may be used for cleaning a mask used in the deposition process of an organic electroluminescent material.

[0044] In the following, specific aspects of the present disclosure are described through examples. These examples are not intended to limit the present disclosure and are used merely as examples.

[0046] Example: Evaluation of the dissolving power of a cleaning composition

[0048] 1) Preparation of a cleaning composition

[0050] To evaluate the dissolving power of the cleaning composition of the present disclosure, a cleaning composition of the example and a cleaning composition of the comparative example were prepared. The composition and content of the cleaning compositions used in the example and comparative example are shown in Table 1 below.

[0052] amide solvents Urea-based solvents Cyrene GBL Aromatic alcohols NEP DMPA DMI BzOH Example 1 90 10 Example 2 90 10 Example 3 90 10 Example 4 70 20 10 Example 5 76 15 9 Example 6 63 30 7 Example 7 72 23 5 Example 8 85 10 5 Example 9 72 25 3 Example 10 82 15 3 Comparative Example 1 100 Comparative Example 2 100 Comparative Example 3 100 Comparative Example 4 70 30 Comparative Example 5 70 30 Comparative Example 6 50 50

[0053] NEP: N-ethyl-2-pyrrolidone

[0054] DMPA: N,N-Dimethylpropionamide

[0055] DMI: 1,3-Dimethyl-2-imidazolidinone

[0056] Cyrene: Dihydrolevoglucosenone

[0057] GBL: Gamma-butyrolactone (γ-Butyrolactone)

[0058] BzOH: Benzyl alcohol

[0060] 2) Solubility Evaluation Method and Results

[0062] 0.025 g of organic electroluminescent sample and 5 ml of cleaning composition were placed in a 30 ml vial, and ultrasound was applied for 20 minutes at 88% power using a 400 W ultrasonic cleaner (Seongdong Ultrasonic, SD-D400H) at 40°C. The particle size of the organic electroluminescent material is hundreds of μm to several mm and is visible to the naked eye. Accordingly, the cleaning power of the cleaning composition on the organic electroluminescent material was evaluated by visually inspecting the organic electroluminescent sample remaining in the cleaning composition.

[0064] The organic electroluminescent samples used for evaluation are as follows:

[0065] DPEPO: Bis[2-(diphenylphosphino)phenyl]ether oxide;

[0066] Alq3: Tris(8-hydroxyquinoline)aluminum;

[0067] BCP: Bathocuproine;

[0068] 2-TNATA: 4,4′,4′′-tris[N-(2-naphthyl)-N-phenylamino]-triphenylamine (4,4',4"-tris(N-(2-naphthyl)-N-phenylamino)-triphenylamine); and

[0069] Anthraquinone

[0071] The results of the solubility evaluation are shown in Table 2 below.

[0073] Evaluation of Organic EL Solubility DPEPO Alq3 BCP 2-TNATA Anthraquinone Example 1 O O O O △ Example 2 O O O O △ Example 3 O O O O △ Example 4 O O O O O Example 5 O O O O O Example 6 O O O O O Example 7 O O O O O Example 8 O O O O O Example 9 O O O O O Example 10 O O O O O Comparative Example 1 O O X O △ Comparative Example 2 O O X O △ Comparative Example 3 O O X O X Comparative Example 4 O O X O △ Comparative Example 5 O O X X △ Comparative Example 6 O O X O △

[0074] <Evaluation Criteria>

[0075] ○: All organic EL material is dissolved.

[0076] △: Organic EL material dissolved by more than 90%

[0077] X: Organic EL material dissolved by less than 90%

[0079] When the cleaning compositions of Examples 1 to 10 were used, the organic electroluminescent materials of DPEPO, Alq3, BCP, and 2-TNATA were all dissolved. Anthraquinone was dissolved by more than 90% in the cleaning compositions of Examples 1 to 3, and was completely dissolved in the cleaning compositions of Examples 4 to 10.

[0081] In contrast, when the cleaning compositions of Comparative Examples 1 to 6 were used, BCP dissolved by less than 90% in all comparative examples. In addition, the cleaning compositions of Comparative Examples 3 and 5 exhibited lower cleaning power than the cleaning compositions of Examples 1 to 10, such as dissolving anthraquinone and 2-TNATA by less than 90%, respectively.

[0083] Specifically, Comparative Examples 1 to 3 used an amide-based solvent or a urea-based solvent alone, and in this case, BCP was dissolved to less than 90%. In contrast, the cleaning compositions of Examples 1 to 10, which mixed an aromatic alcohol solvent with an amide-based solvent, a urea-based solvent, or a combination thereof, completely dissolved BCP. Meanwhile, in the case of the cleaning compositions of Comparative Examples 4 to 6, in which the amide-based solvent, a urea-based solvent, or a combination thereof did not contain aromatic alcohol or additionally contained an aromatic alcohol and a solvent other than the latter, it can be confirmed that, unlike Examples 1 to 10, the dissolving power of the cleaning composition for BCP did not increase. Through this, it can be confirmed that the dissolving power of the cleaning composition increases when the cleaning composition additionally contains an aromatic alcohol with an amide-based solvent, a urea-based solvent, or a combination thereof.

[0085] Similarly, when the cleaning composition of Example 3, which contains a urea-based solvent and an aromatic alcohol, was used, the solubility for anthraquinone increased slightly compared to the cleaning composition of Comparative Example 3, which used only a urea-based solvent. Furthermore, it can be confirmed that the cleaning compositions of Examples 4 to 10, which contain an amide-based solvent, a urea-based solvent, and an aromatic alcohol, dissolve all of the anthraquinone.

[0087] Through this embodiment, it can be confirmed that the cleaning composition of the present disclosure, comprising a first solvent which is an amide-based solvent, a urea-based solvent, or a combination thereof, and a second solvent which is an aromatic alcohol, has an excellent effect in cleaning organic electroluminescent materials. Furthermore, the cleaning composition of the present disclosure has the advantage of being applicable to various materials and situations because it possesses excellent overall dissolving power in various organic electroluminescent materials without containing harmful toxic organic solvents such as NMP.

[0089] Although embodiments have been described as above, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results can be achieved even if the described techniques are performed in a different order than described, and / or the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0090] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

Claims

Claim 1 A composition for cleaning organic electroluminescence (EL) materials, wherein the composition comprises: a first solvent which is a combination of an amide-based solvent and a urea-based solvent; and a second solvent which is an aromatic alcohol-based solvent, wherein the amide-based solvent is 60% to 95% by weight based on the total weight of the first solvent, and the urea-based solvent is 5% to 40% by weight based on the total weight of the first solvent, provided that the amide-based solvent is not N-methyl-2-pyrrolidone. Claim 2 A composition for cleaning organic electroluminescent materials according to claim 1, wherein the amide-based solvent is selected from the group consisting of N,N-dimethylacetamide, N,N-dimethylpropionamide, N,N-diethylformamide, N,N-diethylacetamide, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone, and combinations thereof. Claim 3 A composition for cleaning organic electroluminescent materials according to claim 1, wherein the urea-based solvent is selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, N,N-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diethylurea, and combinations thereof. Claim 4 A composition for cleaning organic electroluminescent materials according to claim 1, wherein the aromatic alcohol-based solvent is selected from the group consisting of benzyl alcohol, 2-phenylethanol, 4-cumylphenol, and combinations thereof. Claim 5 A composition for cleaning organic electroluminescent materials according to claim 1, wherein the first solvent is 80% to 99% by weight of the composition. Claim 6 A composition for cleaning organic electroluminescent materials according to claim 1, wherein the second solvent is 1% to 20% by weight of the composition. Claim 7 delete Claim 8 delete