A cleaning agent for OLED cathode mask surface

Abstract

This application discloses a cleaning agent for the surface of an OLED cathode mask. The cleaning agent comprises the following raw materials in parts by weight: 15-30 parts of component A; wherein component A comprises the following raw materials in parts by weight: 5-20% hydrogen peroxide, 5-20% nitric acid, 2-8% α-PGA, 2-8% HEDP, and 5-10% pH adjuster, with the balance being deionized water. The cleaning agent prepared in this application efficiently removes magnesium-silver alloy from the mask surface, has a fast cleaning rate, and is environmentally friendly.

Description

Technical Field

[0001] The present application relates to the technical field of organic self-luminous diodes, and in particular to a cleaning agent for the surface of an OLED cathode mask. Background Art

[0002] Organic light-emitting diode (OLED) is a new type of light-emitting material. It has the advantages of high brightness, high contrast, high color saturation, low power consumption, thinness, lightness and flexibility. Therefore, it is widely used in display, lighting, biomedicine and other fields.

[0003] An important processing technology in the preparation of OLED is the evaporation process. The physical process of the evaporation process includes: the deposited material evaporates or sublimates into gaseous particles → the gaseous particles are quickly transported from the evaporation source to the substrate surface → the gaseous particles attach to the substrate surface to form nuclei and grow into a solid film → the film atoms are reconstructed or chemically bonded; the evaporation process requires the use of a mask, and the mask determines the pixel height of the OLED display.

[0004] However, during the evaporation process, the evaporation material will be deposited on the mask, blocking the openings, affecting the evaporation effect, and affecting the service life of the mask. The mask needs to be cleaned in a timely manner and has quality requirements.

[0005] Currently, the main cathode material for OLED is magnesium-silver alloy. The magnesium-silver alloy formed by vapor deposition has a high silver content and is difficult to remove. It also may corrode the mask plate, affecting subsequent use.

[0006] Therefore, it is urgent to develop a cleaning agent that can efficiently remove the magnesium-silver alloy deposited on the mask and has low corrosion to the mask. Summary of the Invention

[0007] In order to solve at least one of the above technical problems, a cleaning agent is developed that can efficiently remove the magnesium-silver alloy deposited on the mask and has low corrosiveness to the mask. The present application provides a cleaning agent for the surface of the OLED cathode mask.

[0008] The present application provides a cleaning agent for the surface of an OLED cathode mask, comprising the following raw materials in parts by weight: 15-30 parts of component A;

[0009] The component A comprises the following raw materials in weight fractions: 5-20% hydrogen peroxide, 5-20% nitric acid, 2-8% α-PGA, 2-8% HEDP and 5-10% pH regulator, with the balance being deionized water.

[0010] By adopting the above technical solution, the cleaning agent prepared in the present application can efficiently remove the magnesium-silver alloy on the surface of the mask with a fast cleaning rate; at the same time, when the iron on the mask reacts with nitric acid, the trivalent iron generated can form an iron chelate with the composite system of α-PGA and HEDP, and after film formation, it adheres to the surface of the mask, preventing further corrosion of the mask; α-PGA has excellent compatibility, good compatibility with the raw materials in the cleaning agent, and is environmentally friendly and pollution-free.

[0011] Optionally, the weight ratio of α-PGA to HEDP is (0.5-2):1.

[0012] By adopting the above technical solution, the present application selects a more optimal ratio of α-PGA and HEDP to prepare a cleaning agent that forms a better film and adheres to the surface of the mask, thereby preventing further corrosion of the mask.

[0013] Optionally, 2-6 parts of component B are further included, wherein the component B is one or more of aluminum powder or zinc powder.

[0014] By adopting the above technical solution, the cleaning agent prepared in the present application also includes aluminum powder or zinc powder. The presence of aluminum powder and zinc powder allows the magnesium-silver on the mask to react completely and then react with the aluminum powder and zinc powder first, thereby acting as a barrier and preventing hydrogen peroxide and acid from reacting with iron and corroding the mask.

[0015] Optionally, 5-10 parts of component C are also included, and the component C is silicic acid solution and polyacrylamide.

[0016] By adopting the above technical solution, the cleaning agent of the present application also includes a silicate solution and polyacrylamide. The cleaning agent after cleaning the mask contains a large amount of metal ions. The presence of metal ions causes the hydrogen peroxide to decompose rapidly, thereby causing the cleaning agent to quickly become ineffective and unable to be recycled multiple times. The presence of the silicate solution causes the large amount of metal ions contained in the cleaning agent to form colloids or precipitates. The filtrate obtained after separation can be stored in a container for reuse, thereby increasing the storage period and reducing costs. The compounding of polyacrylamide and silicate solution promotes the aggregation of colloids or precipitates, thereby reducing the processing time of the cleaning agent after use.

[0017] Optionally, the content of the polyacrylamide is 100 ppm or less.

[0018] Optionally, the molecular weight of the polyacrylamide is 18-20 million.

[0019] By adopting the above technical solution, the content of polyacrylamide is controlled to avoid excessive addition leading to increased viscosity, which affects the subsequent reuse of the cleaning agent; the molecular weight of polyacrylamide is controlled to make polyacrylamide anionic, which promotes aggregation with metal ions.

[0020] Optionally, the concentration of the silicic acid solution is 5-10 wt%.

[0021] Optionally, the concentration of the hydrogen peroxide is 2-8 wt %.

[0022] Optionally, the pH adjuster is one or more of potassium citrate, citric acid, malic acid or tartaric acid.

[0023] In summary, the present invention includes at least one of the following beneficial technical effects:

[0024] 1. The cleaning agent prepared in this application can effectively remove magnesium-silver alloy from the surface of the mask with a fast cleaning rate. The compound system of α-PGA and HEDP can form an iron chelate, which adheres to the surface of the mask after forming a film, preventing corrosion of the mask. α-PGA has excellent compatibility with the raw materials in the cleaning agent and is environmentally friendly.

[0025] 2. The cleaning agent prepared in the present application also includes aluminum powder or zinc powder. The presence of aluminum powder and zinc powder allows the magnesium and silver on the mask to react completely before reacting with the aluminum and zinc powders, thus acting as a barrier and preventing hydrogen peroxide and acid from reacting with iron and corroding the mask.

[0026] 3. The cleaning agent of the present application also includes a silicic acid solution and polyacrylamide, so that a large amount of metal ions are contained in the cleaning agent to form colloids or precipitates. The filtrate obtained after separation can be stored in a container and reused, thereby increasing the storage period and reducing costs. The compounding of polyacrylamide and silicic acid solution promotes the aggregation of colloids or precipitates. DETAILED DESCRIPTION

[0027] Glossary:

[0028] α-PGA: poly-L-glutamic acid;

[0029] HEDP: hydroxyethylidene diphosphonic acid.

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] The present application designs a cleaning agent for the surface of an OLED cathode mask, comprising the following raw materials in parts by weight: 15-30 parts of component A;

[0032] The component A comprises the following raw materials in weight fractions: 5-20% hydrogen peroxide, 5-20% nitric acid, 2-8% α-PGA, 2-8% HEDP and 5-10% pH regulator, with the balance being deionized water.

[0033] Optionally, 2-6 parts of component B are further included, wherein the component B is one or more of aluminum powder or zinc powder.

[0034] Optionally, 5-10 parts of component C are also included, and the component C is silicic acid solution and polyacrylamide.

[0035] Prior to this application, existing cleaning agents for cleaning masks took too long to clean and caused significant corrosion to the masks, affecting their further use. Furthermore, the presence of a large amount of metal ions in the cleaning agents caused the hydrogen peroxide to decompose rapidly, causing the cleaning agents to quickly become ineffective and unable to be recycled multiple times, shortening their storage period.

[0036] In response to the above problems, the inventors of the present application have designed the technical solution of the present application. The prepared cleaning agent can effectively remove the magnesium-silver alloy on the surface of the mask, has a fast cleaning rate, and does not affect the use of the mask or the storage of the cleaning agent. First, the present application designs a compound system of α-PGA and HEDP, so that the iron on the mask reacts with nitric acid, and the generated trivalent iron forms an iron chelate. After forming a film, it adheres to the surface of the mask and prevents further corrosion of the mask. α-PGA has excellent compatibility with the raw materials in the cleaning agent and is environmentally friendly and pollution-free.

[0037] Secondly, the present application designs the addition of aluminum powder and / or zinc powder to the cleaning agent. The presence of aluminum powder and zinc powder allows the magnesium-silver on the mask to react completely and then react with the aluminum powder and zinc powder first, thereby acting as a barrier and preventing hydrogen peroxide and acid from directly reacting with iron and corroding the mask.

[0038] Finally, the present application designs a silicate solution and polyacrylamide. The cleaning agent after cleaning the mask contains a large amount of metal ions. The presence of metal ions causes the hydrogen peroxide to decompose rapidly, which in turn causes the cleaning agent to quickly become ineffective and unable to be recycled multiple times. The presence of silicate solution causes the cleaning agent to contain a large amount of metal ions to form colloids or precipitates. The filtrate obtained after separation can be stored in a container and reused, which increases the storage period and reduces costs. The compounding of polyacrylamide and silicate solution promotes the aggregation of colloids or precipitates, reducing the processing time of the cleaning agent after use.

[0039] The method of using the cleaning agent prepared in the present application is as follows: at room temperature, components A and B are placed in a container in sequence, and the magnesium-silver alloy on the mask is ultrasonically removed. After cleaning, component C is placed in the cleaning agent after the mask is cleaned. At this time, component C forms a colloid or precipitate with a large amount of metal ions. The filtrate obtained after centrifugal separation and semipermeable membrane separation is placed in a storage tank for next use. Specific embodiments

[0041] Unless otherwise specified, the raw materials used in this application are all commercially available:

[0042] Nitric acid: concentration 5-10wt%;

[0043] α-PGA: purity 98%;

[0044] HEDP: active substance content: 99%;

[0045] Potassium citrate: purity 98%;

[0046] Citric acid: purity 99%;

[0047] Malic acid: purity 99%;

[0048] Tartaric acid: purity 95%.

[0049] Test items and methods:

[0050] Mg / Ag removal rate: Use X-ray energy dispersive spectrometry (EDS) to detect the residual Mg / Ag content on the mask surface and compare it with the initial content;

[0051] Corrosion test: Fill a 500mL glass with 300mL of a 20% aqueous solution of a cleaning agent of different formulations, place a small mask sample weighed to a constant weight, and seal the lid with a sealing ring to prevent water evaporation. Soak at room temperature for one week, then rinse with pure water, dehydrate with IPA, dry to a constant weight, and weigh again. The test is evaluated by the weight change ratio between the two weighings.

[0052] Cleaning time: Use a timer to count the time required to clean the magnesium-silver alloy on the mask surface;

[0053] Metal ion content: detected by inductively coupled plasma mass spectrometry (ICP-MS);

[0054] Cleaning agent storage time: Statistics on the storage time of cleaning agents before they expire.

[0055] Examples 1-6

[0056] The contents of component A in Examples 1-6 are shown in Table 1.

[0057] Table 1 Content of component A in Examples 1-6

[0058]

[0059] Wherein, the concentration of hydrogen peroxide in Example 1 is 8 wt %, and the pH regulator is 6 kg of potassium citrate;

[0060] In Example 2, the concentration of hydrogen peroxide is 6 wt %, and the pH adjusters are 2 kg of potassium citrate and 3 kg of citric acid;

[0061] In Example 3, the concentration of hydrogen peroxide is 4 wt %, and the pH regulator is 8 kg of malic acid;

[0062] In Example 4, the concentration of hydrogen peroxide is 2 wt %, and the pH adjusters are 5 kg of malic acid and 5 kg of tartaric acid;

[0063] In Example 5, the concentration of hydrogen peroxide is 3 wt %, and the pH adjuster is 7 kg of tartaric acid;

[0064] In Example 6, the concentration of hydrogen peroxide is 5 wt %, and the pH adjusters are 2 kg of potassium citrate, 3 kg of citric acid, 2 kg of malic acid, and 2 kg of tartaric acid;

[0065] The specific raw material content in component A is shown in Table 2.

[0066] Table 2 Raw material content in component A of Examples 1-6

[0067]

[0068] The balance was deionized water.

[0069] The raw materials of component A of Examples 1-6 were mixed and stirred uniformly at room temperature to prepare a cleaning agent. The prepared cleaning agent was subjected to relevant performance tests. The test results are shown in Table 3.

[0070] Table 3 Properties of the cleaning agents prepared in Examples 1-6

[0071]

[0072] It can be seen from Examples 1-6 and Table 3 that the cleaning agent prepared in the present application can completely remove the magnesium-silver alloy when cleaning the mask. At the same time, the cleaning time is short, not exceeding 10 seconds, and the corrosion to the mask is also small, with a maximum of 0.0012%, which does not affect the subsequent use of the mask.

[0073] Examples 7-12

[0074] Based on Example 1, except for the different ratios of α-PGA and HEDP, the other raw materials and preparation methods are the same as those in Example 1, as shown in Table 4.

[0075] Table 4 Ratio of α-PGA and HEDP

[0076]

[0077] The cleaning agents prepared in Examples 7-12 were subjected to relevant performance tests, and the test results are shown in Table 5.

[0078]

[0079] As can be seen from Examples 7-12 and Table 5, the present application controls the ratio of α-PGA and HEDP and selects the optimal ratio range. The corrosion performance of the cleaning agent prepared on metals is less corrosive than that of Example 1, and the optimal corrosion is only 0.00028%.

[0080] Examples 13-17

[0081] Example 13

[0082] Based on Example 9, in addition to component A, 2 kg of component B was added, wherein component B was aluminum powder. The remaining components and preparation method were the same as those in Example 9.

[0083] Example 14

[0084] Based on Example 9, in addition to component A, 3 kg of component B was added, wherein component B was zinc powder. The remaining components and preparation method were consistent with those of Example 9.

[0085] Example 15

[0086] Based on Example 9, in addition to component A, 4 kg of component B was added, wherein component B was 2 kg of aluminum powder and 2 kg of zinc powder. The remaining components and preparation method were consistent with Example 9.

[0087] Example 16

[0088] Based on Example 9, in addition to component A, 5 kg of component B was added, wherein component B was aluminum powder. The remaining components and preparation method were consistent with Example 9.

[0089] Example 17

[0090] Based on Example 9, in addition to component A, 6 kg of component B was added, wherein component B was 2 kg of aluminum powder and 4 kg of zinc powder. The remaining components and preparation method were consistent with Example 9.

[0091] The cleaning agents prepared in Examples 13-17 were subjected to relevant performance tests, and the test results are shown in Table 6.

[0092] Table 6 Properties of the cleaning agents prepared in Examples 13-17

[0093]

[0094] As can be seen from Examples 13-17 and Table 6, the addition of component B to the cleaning agent prepared in the present application can reduce or even prevent corrosion of the mask, and the cleaning time is short and the magnesium-silver alloy is completely removed. As can be seen from Examples 15-17 and Table 6, the appropriate content of component B can be selected according to the content of magnesium-silver alloy on the mask.

[0095] Examples 18-25

[0096] Based on Example 13, in addition to components A and B, component C is also contained. The remaining components and preparation method are consistent with Example 13. The content of each component of component C is shown in Table 7.

[0097] Table 7 Content of each component of component C in Examples 18-25

[0098]

[0099] Among them, the molecular weight of the polyacrylamide of Example 18-19 is 18 million;

[0100] The molecular weight of the polyacrylamide in Examples 20-21 is 19 million;

[0101] The molecular weight of the polyacrylamide in Examples 22-23 is 20 million;

[0102] How to use component C: At room temperature, place components A and B in a container in turn, and ultrasonically remove the magnesium-silver alloy on the mask. After cleaning, place component C in the cleaning agent after the mask is cleaned. At this time, component C forms a colloid or precipitate with a large amount of metal ions. The filtrate obtained after centrifugal separation and semi-permeable membrane separation is placed in a storage tank for next use.

[0103] Example 24

[0104] Based on Example 18, except that the polyacrylamide content is 0, the other components and preparation methods are the same as Example 18.

[0105] Example 25

[0106] Based on Example 18, except that the polyacrylamide content was 120 ppmm, the other components and preparation methods were the same as those in Example 18.

[0107] Component C was mixed evenly at room temperature and reacted with the cleaning agent after mask cleaning in Examples 18-25. The residual metal ion content in the cleaning agent and the storage time of the cleaning agent were tested. The test results are shown in Table 8.

[0108] Table 8 Indicators of the cleaning agents after treatment in Examples 18-25 As can be seen from Examples 18-23 and Table 8, the cleaning agent prepared in the present application is added with component C, which can remove metal ions in the cleaning agent, so that the residual metal ions in the cleaning agent are small, the impact on the decomposition of the cleaning agent is reduced, and the storage time of the cleaning agent is increased, which can be stored for at least 45 days.

[0109] It can be seen from Examples 24-25 and Table 8 that when the polyacrylamide content is 0 or the polyacrylamide content is too high, the removal of metal ions in the cleaning agent will be affected.

[0110] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, all equivalent changes made based on the principles of the present application should be included in the scope of protection of the present application.

Claims

1. A cleaning agent for the surface of an OLED cathode mask, characterized in that: The composition comprises the following raw materials in parts by weight: 15-30 parts of component A; The component A comprises the following raw materials by weight: 5-20% hydrogen peroxide, 5-20% nitric acid, 2-8% α-PGA, 2-8% HEDP and 5-10% pH adjuster, with the balance being deionized water; Also includes 2-6 parts of component B, wherein the component B is one or more of aluminum powder or zinc powder; The invention also includes 5-10 parts of component C, which is silicic acid solution and polyacrylamide.

2. The cleaning agent for the surface of an OLED cathode mask according to claim 1, characterized in that: The weight ratio of the α-PGA to HEDP is (0.5-2):

1.

3. The cleaning agent for the surface of an OLED cathode mask according to claim 2, characterized in that: The content of the polyacrylamide is 100 ppm or less.

4. The cleaning agent for the surface of an OLED cathode mask according to claim 2, characterized in that: The molecular weight of the polyacrylamide is 18-20 million.

5. The cleaning agent for the surface of an OLED cathode mask according to claim 2, characterized in that: The concentration of the silicic acid solution is 5-10 wt %.

6. The cleaning agent for the surface of an OLED cathode mask according to claim 1, characterized in that: The concentration of the hydrogen peroxide is 2-8 wt %.

7. The cleaning agent for the surface of an OLED cathode mask according to claim 1, characterized in that: The pH regulator is one or more of potassium citrate, citric acid, malic acid or tartaric acid.

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