Removal of electroluminescent material from substrate

Abstract

The composition comprises a hydrofluorothioether represented by structural formula (I): Rf-S-Rh (I), where Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more linearly linked heteroatoms or chlorine atoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms. The composition further comprises an electroluminescent material.

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to compositions and methods for removing electroluminescent materials from substrates. [Background technology]

[0002] Various compositions for removing electroluminescent materials from metal substrates are described, for example, in US Pat. No. 7,073,518. Summary of the Invention

[0003] In some embodiments, the composition has the following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more linearly linked heteroatoms or chlorine atoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms. The composition further comprises an electroluminescent material.

[0004] The above summary of the present disclosure is not intended to describe every embodiment of the present disclosure. The details of one or more embodiments of the present disclosure are also set forth in the following description. Other features, objects, and advantages of the present disclosure will become apparent from the specification and claims. DETAILED DESCRIPTION OF THE INVENTION

[0005] In organic light-emitting diode (OLED) manufacturing processes, it is common for electroluminescent materials to be deposited (or otherwise present) on metal masks. To reuse these metal masks, the electroluminescent material must be removed. Specific solvents, such as N-methyl-2-pyrrolidone (NMP), N-2-butylpyrrolidone (NBP), cyclohexanone, or isopropyl alcohol (IPA), can be used to remove the electroluminescent material from the metal mask. Following removal of the electroluminescent material, the solvent must be removed (e.g., rinsed) from the metal mask using an additional solvent (e.g., hydrofluoroether fluid) because the drying time of such initial solvents is unacceptably long due to their high boiling points. Furthermore, the use of these solvents is generally undesirable due to their unfavorable environmental profile (e.g., high GWP), toxicity profile, or flash point (i.e., safety concerns).

[0006] Recently, compositions have been developed that facilitate the removal of electroluminescent materials in a single step. However, these compositions are azeotropic blends of hydrofluorochemicals and organic solvents (e.g., trans-dichloroethylene) that form azeotropes. Such multi-component compositions are less than ideal because they contain chlorine-containing materials (e.g., trans-dichloroethylene) that the industry prefers to avoid for acceptable cleaning performance.

[0007] As a result, compositions and methods for removing electroluminescent materials from metal masks that (i) use a single component composition (as opposed to a blend) and can be performed in a single-step process (i.e., a process that may not require an additional rinsing step), and / or (ii) use materials with a more favorable toxicity profile and / or no flash point, may be desirable.

[0008] In general, the present disclosure is directed to compositions and methods for removing electroluminescent materials from metal masks, which compositions and methods include certain hydrofluorothioethers. Surprisingly, these hydrofluorothioethers exhibit a unique combination of cleaning performance and accelerated drying times (i.e., enabling a one-step process), while also providing favorable toxicity, non-flammability, and environmental profiles.

[0009] As used herein, "fluoro-" (e.g., with respect to a group or moiety, such as in "fluoroalkylene" or "fluoroalkyl" or "fluorocarbon") or "fluorinated" means partially fluorinated so that there is at least one hydrogen atom bonded to a carbon.

[0010] As used herein, "perfluoro" (e.g., with respect to a group or moiety, such as in "perfluoroalkylene" or "perfluoroalkyl" or "perfluorocarbon") or "perfluorinated" means fully fluorinated, and unless otherwise indicated, there are no carbon-bonded hydrogen atoms available for replacement with fluorine.

[0011] As used herein, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the accompanying embodiments, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0012] As used herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).

[0013] Unless otherwise indicated, all numbers expressing quantities or ingredients, measurements of properties, and the like used in the specification and embodiments are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and accompanying list of embodiments may vary depending upon the desired properties sought to be obtained by one of ordinary skill in the art utilizing the teachings of the present disclosure. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques; however, this is not intended to limit the application of the doctrine of equivalents to the scope of the claimed embodiments.

[0014] In some embodiments, the present disclosure relates to compositions for removing electroluminescent materials from substrates (e.g., metal masks of the type commonly used in OLED manufacturing processes). The compositions can include one or more hydrofluorothioether compounds.

[0015] In some embodiments, suitable hydrofluorothioethers have the following structural formula (I): It is represented by Rf-S-Rh (I).

[0016] In some embodiments, Rf is a partially fluorinated or perfluorinated group having 2 to 9, 2 to 6, 2 to 5, or 2 to 4 carbon atoms that is saturated or unsaturated, straight or branched, acyclic or cyclic, and optionally contains one or more catenated heteroatoms, chlorine atoms, or bromine atoms. In some embodiments, Rf is partially fluorinated. In some embodiments, Rf has two or fewer hydrogen atoms. In some embodiments, Rf is perfluorinated. In some embodiments, Rf is a perfluorinated, saturated, branched group having 3 to 6 carbon atoms.

[0017] In some embodiments, Rh is a saturated or unsaturated, straight or branched chain, non-fluorinated hydrocarbon group having 1 to 3 or 1 to 2 carbon atoms, optionally containing one or more catenated heteroatoms. In some embodiments, Rh is CH3 or CH3CH2. In some embodiments, Rh is CH3.

[0018] In some embodiments, suitable hydrofluorothioethers have the following structural formula (II): [ka] is expressed by

[0019] In some embodiments, n is 0 or 1, x is an oxygen atom or a sulfur atom, (i) Rh' is a partially fluorinated alkyl group having 1 to 4 or 1 to 3 carbon atoms and at least one hydrogen atom, optionally including one or more catenated heteroatoms, chlorine atoms, or bromine atoms, and Rf' is a perfluoroalkyl group having 1 to 4 or 1 to 3 carbon atoms, optionally including one or more catenated heteroatoms, chlorine atoms, or bromine atoms, or (ii) Rh' and Rf' are joined together to form a 5- or 6-membered fluorinated ring having at least one hydrogen atom, optionally including one or more catenated heteroatoms, chlorine atoms, or bromine atoms.

[0020] In some embodiments, any of the heteroatoms in the above-mentioned chains may be a secondary O heteroatom, where O is bonded to two carbon atoms. In some embodiments, any of the heteroatoms in the above-mentioned chains may be a tertiary N heteroatom, where N is bonded to three carbon atoms.

[0021] In some embodiments, the fluorine content of the hydrofluorothioether compounds of the present disclosure may be sufficient to render the compounds non-flammable according to ASTM D-3278-96 e-1 test method (“Flash Point of Liquids by Small Scale Closed Cup Apparatus”).

[0022] In various embodiments, representative examples of compounds of general formula (I) include: CF3CF2-S-CH3, HCF2CF2-S-CH3, HCFClCF2-S-CH3, CF2ClCF2-S-CH3, CF3CFCl-S-CH3, CF3CF2CF2-S-CH3, CF3OCF2CF2-S-CH3, CF3CHFCF2-S-CH3, (CF3)2CF-S-CH3, (CF3)2CF-S-CH2Cl, CF3CHFCF2-S-CH3, CF3CF2CF2CF2-S-CH3, (CF3)2CFCF2-S-CH3, CF3CF(CF3)CF2-S-CH3, CF3CF2CF(CF3)-S-CH3, CF3OCF2CF2CF2-S-CH3, CF3CF2CF2CF2-S-CH2CH3, CF3CF2CF2CF2-S-CH2OCH3, CF3CF2CF(CF3)-S-CH2CH3, CF3CF2CF2CF2-S-CH2CH3, (CF3)2NCF2-S-CH3, [ka]

[0023] In some embodiments, the present disclosure is directed to a working fluid for removing electroluminescent materials from a substrate. The working fluid may comprise the above-described hydrofluorothioether compound in an amount of at least 50 wt%, at least 70 wt%, at least 90 wt%, at least 95 wt%, or at least 99 wt%, based on the total weight of the composition. In some embodiments, the working fluid may consist essentially of the hydrofluorothioether of the present disclosure. In some embodiments, such working fluids may also comprise one or more additional solvents (e.g., NMP, NBP, cyclohexanone, or IPA). For example, such additional solvents may be present in the working fluid, but in an amount of less than 10 wt%, less than 5 wt%, or less than 1 wt%, based on the total weight of the working fluid.

[0024] It should be appreciated that the compositions of the present disclosure have been found to adequately remove electroluminescent materials (e.g., OLED dyes) from the surface of metal substrates and are associated with significantly shorter dry times relative to materials traditionally used in metal mask cleaning processes (e.g., NMP, cyclohexanone, and IPA).

[0025] In some embodiments, the present disclosure is further directed to the above compositions in a post-clean state. In this regard, the present disclosure is directed to any of the above cleaning compositions comprising one or more electroluminescent materials dissolved, dispersed, or otherwise contained therein. In some embodiments, the electroluminescent material may include any highly conjugated dye that responds to an electrical stimulus (such as those often used in OLED manufacturing processes). In some embodiments, the electroluminescent material may include copper(II) phthalocyanine, iridium, or platinum. In some embodiments, the electroluminescent material may be present in the post-clean composition in an amount of at least 0.001 wt % or at least 0.01 wt %, based on the total weight of the post-clean composition.

[0026] In some embodiments, the compositions of the present disclosure have a favorable toxicity profile as described above. More specifically, the compositions of the present disclosure may have a more favorable toxicity profile than materials commonly used to clean electroluminescent materials from metal masks (e.g., NMP).

[0027] In some embodiments, the present disclosure is further directed to a method for cleaning a metal substrate. More specifically, in some embodiments, the present disclosure is further directed to a method for removing an electroluminescent material from a metal mask (such as those commonly used in OLED manufacturing processes). In some embodiments, the method first includes providing a metal substrate (e.g., a metal mask) having an electroluminescent material disposed on an outer surface of the substrate. The electroluminescent material can be disposed on the outer surface in a layer having a thickness of at least 10,000 angstroms, at least 15,000 angstroms, or at least 20,000 angstroms.

[0028] In some embodiments, the method can then include contacting the electroluminescent material bearing the metal mask with either the hydrofluorothioether or working fluid described above. The hydrofluorothioether or working fluid can be used in either the gaseous or liquid state (or both), and any known or future technique for "contacting" the substrate can be used. For example, a liquid composition can be sprayed or brushed onto the substrate, a gaseous composition can be sprayed over the entire substrate, or the substrate can be exposed (partially or completely) to either the gaseous or liquid composition. High temperature, ultrasonic energy, and / or agitation can be used to facilitate cleaning. In some embodiments, the method of the present disclosure is carried out at room temperature. A variety of different cleaning techniques are described by B.N. Ellis in "Cleaning and Contamination of Electronic Components and Assemblies," Electrochemical Publications Limited, Ayr, Scotland, pp. 182-94 (1986), which is incorporated herein by reference in its entirety. The method can then include removing the hydrofluorothioether or working fluid from the metal mask. Such removal can be carried out via simple evaporation, as the hydrofluorothioethers of the present disclosure have been found to evaporate readily, leaving a clean, dry metal mask surface.

[0029] In some embodiments, the hydrofluorothioethers (or hydrofluorothioether-containing working fluids) of the present disclosure may also be used in combination with one or more commonly used solvents (e.g., NMP, NBP, cyclohexanone, or IPA) for removing electroluminescent material from metal masks. In such embodiments, the method may first include contacting the electroluminescent material-bearing metal mask with any one or more of the commonly used solvents. In these embodiments, the commonly used solvents may be characterized as the primary mechanism for transferring the electroluminescent material from the metal mask. It should be understood that after transfer of the electroluminescent material, some amount of solvent remains on the metal mask. As previously mentioned, the drying times of such solvents are unacceptably long, due in large part to their high boiling points. To promote faster drying, in some embodiments, the method of the present disclosure may include removing the solvent by contacting the solvent-bearing metal mask with either the hydrofluorothioethers or working fluids described above. In this regard, the hydrofluorothioethers of the present disclosure have been discovered to efficiently wet and displace commonly used solvents and to evaporate rapidly. It has further been discovered that hydrofluorothioethers exhibit exceptional stability in the presence of amine-containing solvents (NMP and NBP). In this embodiment, such stability can be important in that instability can lead to fluoride generation, significantly reducing the effectiveness of fluorinated solvents for cleaning. Instability can also result in the formation of hydrogen fluoride, which would result in undesirable hardware etching. As with the previous embodiment, the method can then include removing the hydrofluorothioether or working fluid from the metal mask (e.g., via evaporation). [Example]

[0030] Objects and advantages of the present disclosure are further illustrated by the following comparative examples and examples. Unless otherwise noted, all parts, percentages, ratios, etc. in the examples and elsewhere in this specification are by weight, and all reagents used in the examples were obtained or are available from common chemical suppliers, such as Sigma-Aldrich Corp. (Saint Louis, MO, US), or can be synthesized by conventional methods.

[0031] [Table 1]

[0032] Preparation of hydrofluoroether HTFE1: (CF3)2CFSCH3 A dry 600 mL Hastalloy Parr reactor was charged with sublimed sulfur (36 g, 1.1 mol), anhydrous spray-dried potassium fluoride (15 g, 260 mmol), and anhydrous N,N-dimethylformamide (300 mL). The reactor was sealed and the contents were heated to 60°C with stirring. Once the reactor was stabilized at this temperature, hexafluoropropene (150 g, 1.0 mol) was added at a rate of 6 g / min, maintaining the temperature below 65°C. Upon completion of the addition, the reaction was stirred at 60°C for 1 hour and then cooled to ambient temperature. The resulting slurry was transferred to a 2 L round-bottom flask to accommodate the addition of the remaining reagents. Potassium fluoride (116 g, 2.0 mol) was added in one portion, followed by dimethyl sulfate (104 mL, 1.1 mol) via the addition funnel at a rate that maintained the internal reaction temperature below 45°C. Once the addition was complete, the resulting reaction mixture was stirred at ambient temperature for 12 hours. The heterogeneous solution was then filtered to remove solids and then washed three times with an equal volume of water. The lower phase was collected, dried over magnesium sulfate, and filtered. The crude material was recovered as a pale yellow oil (117 g, 93% desired product by GC-fid). This material was purified by distillation at ambient pressure to give perfluoroisopropylmethyl thioether (98 g, 45% yield, boiling point 65 °C).

[0033] Solubility of organic light-emitting materials in hydrofluoroethers and comparative solvents Test mixtures were prepared by adding 0.01 g (gram) of one of the electroluminescent materials (ALQ3 or FIrPic) to 3 g of one of the fluids (NMP, NBP, CHO, NOVEC 73DE, or HFTE1). Each mixture was stirred for 5 minutes, and the resulting material was visually inspected for turbidity and undissolved particulate matter. A qualitative solubility rating was assigned to each mixture, as described in Table 2. The results are shown in Table 3. A solubility rating of 1 or 2 was interpreted to mean that the fluid was useful for cleaning electroluminescent materials from substrates such as metal mesh.

[0034] [Table 2]

[0035] [Table 3]

[0036] boiling point The boiling points of the single-component fluid solvents are summarized in Table 4. A relatively low boiling point is interpreted as an indication of a relatively short drying time. The boiling point of HFTE1 is much lower than that of NMP, NBP, and CHO, indicating that HFTE1 dries more quickly than the comparative compounds.

[0037] [Table 4]

[0038] Various modifications and alterations to the present disclosure will become apparent to those skilled in the art without departing from the scope and spirit of the disclosure. It is understood that the present disclosure is not intended to be unduly limited by the exemplary embodiments and examples set forth herein, and that such examples and embodiments are presented merely as examples within the scope of the present disclosure, which is intended to be limited only by the claims set forth herein as follows. All references cited in this disclosure are incorporated herein by reference in their entirety. The present invention includes the following aspects. (1) The following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more linearly linked heteroatoms or chlorine atoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms; an electroluminescent material. (2) The composition according to item 1, wherein Rf is a perfluorinated saturated group having 2 to 5 carbon atoms. (3) Rh is CH 3 or CH 3 CH 2 3. The composition according to item 1 or 2, wherein (4) The composition according to any one of items 1 to 3, wherein the electroluminescent material comprises copper(II) phthalocyanine, iridium, or platinum. (5) The composition according to any one of items 1 to 4, wherein the electroluminescent material is dissolved in the composition. (6) The composition according to any one of items 1 to 5, wherein the compound having structural formula (I) is present in the composition in an amount of at least 50% by weight, based on the total weight of the composition. (7) A process for removing an electroluminescent material from a substrate, comprising: The substrate has the following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more linearly linked heteroatoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms. (8) The process according to item 7, wherein Rf is a perfluorinated saturated group having 2 to 5 carbon atoms. (9) Rh is CH 3 or CH 3 CH 2 9. The process according to item 7 or 8, wherein (10) The process according to any one of items 7 to 9, wherein the electroluminescent material comprises copper(II) phthalocyanine, iridium, or platinum. (11) The process according to any one of items 7 to 10, wherein the substrate comprises a metal. (12) The process of item 11, wherein the electroluminescent material is disposed on an outer surface of the metal. (13) A process for removing an electroluminescent material from a substrate, comprising: contacting the substrate with a solvent selected from the group consisting of NMP, NBP, cyclohexanone, and IPA; The substrate has the following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having from 2 to 9 carbon atoms, optionally containing one or more linearly linked heteroatoms, and Rh is a non-fluorinated hydrocarbon group having from 1 to 3 carbon atoms. (14) The process according to item 13, wherein the step of contacting the substrate with the hydrofluorothioether is carried out after the step of contacting the substrate with the solvent. (15) The process according to item 13 or 14, wherein Rf is a perfluorinated saturated group having 2 to 5 carbon atoms. (16) Rh is CH 3 or CH 3 CH 2 16. The process according to any one of items 13 to 15, (17) The process according to any one of items 13 to 16, wherein the electroluminescent material comprises copper(II) phthalocyanine, iridium, or platinum. (18) The process according to any one of items 13 to 17, wherein the substrate comprises a metal. 19. The process of claim 18, wherein the electroluminescent material is disposed on an outer surface of the metal. (20) The following structural formula (II):

change

Claims

1. The following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more catenated heteroatoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms; and an OLED dye.

2. The composition of claim 1, wherein Rf is a perfluorinated saturated group having from 2 to 5 carbon atoms.

3. Rh is CH ３ or CH ３ CH ２ The composition according to claim 1 or 2,

4. The composition of any one of claims 1 to 3, wherein the OLED pigment comprises copper (II) phthalocyanine, iridium, or platinum.

5. 5. The composition of any one of claims 1 to 4, wherein the compound having structural formula (I) is present in the composition in an amount of at least 50% by weight, based on the total weight of the composition.

6. 1. A process for removing an OLED dye from a substrate, comprising: The substrate is represented by the following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having 2 to 9 carbon atoms, optionally containing one or more catenated heteroatoms, and Rh is a non-fluorinated hydrocarbon group having 1 to 3 carbon atoms.

7. 1. A process for removing an OLED dye from a substrate, comprising: contacting the substrate with a solvent selected from the group consisting of NMP, NBP, cyclohexanone, and IPA; The substrate is represented by the following structural formula (I): Rf-S-Rh (I) wherein Rf is a fluorinated or perfluorinated group having from 2 to 9 carbon atoms, optionally containing one or more catenated heteroatoms, and Rh is a non-fluorinated hydrocarbon group having from 1 to 3 carbon atoms; A process wherein the step of contacting the substrate with a hydrofluorothioether occurs after the step of contacting the substrate with the solvent.

8. The process of claim 7 , wherein the substrate comprises a metal.

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