Polymers for use in electronic devices

Abstract

To provide polyimides which improve their optical transparency and reduce the amber color and birefringence that leads to optical retardation.SOLUTION: There is provided a polyimide film prepared from a liquid composition comprising a liquid composition comprising (a) a polyamic acid having a repeat unit structure of Formula I wherein Ra is the same or different at each occurrence and represents one or more tetracarboxylic acid component residues and Rb is the same or different at each occurrence and represents one or more diamine component residues, (b) one or more phosphorous-containing additives and (c) a high-boiling aprotic solvent. There are also disclosed processes for making the film and uses of the film in electronic devices.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to novel liquid compositions. The present disclosure also relates to polyimide films made from such compositions, methods for making such polyimide films, and electronic devices having at least one layer comprising these polyimide films. [Background technology]

[0002] Materials for use in electronics applications often have strict requirements for their structural, optical, thermal, electrical, and other properties. As the number of commercial electronics applications continues to grow, the breadth and specificity of required properties strongly demands the innovation of materials with new and / or improved properties. Polyimides refer to a class of polymer compounds that have been widely used in a variety of electronics applications. With the right properties, they can serve as flexible alternatives to glass in electronic display devices. These materials can function as components of liquid crystal displays ("LCDs"), where modest power consumption, light weight, and flat layers are crucial characteristics for effective use. Other uses for electronic display devices where such parameters are important include device substrates, substrates for color filter sheets, cover films, touchscreen panels, and others.

[0003] Some of these components are also important in the construction and operation of organic electronic devices, including organic light-emitting diodes ("OLEDs"). OLEDs are promising for numerous display applications due to their high power conversion efficiency and wide range of end-user applicability. They are increasingly being used in mobile phones, tablet devices, handheld / laptop computers, and other commercial products. These applications require displays with large information content, full color, and fast video-speed response times, in addition to low power consumption.

[0004] Polyimide films generally have sufficient thermal stability, high glass transition temperatures, and mechanical toughness to justify such use, and polyimides generally do not develop haze even with repeated flexing, making them often preferred over other transparent substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) for flexible display applications.

[0005] However, the traditional brown color of polyimides precludes their use in some display applications, such as color filters and touchscreen panels, due to their emphasis on optical transparency. Furthermore, polyimides are generally rigid, highly aromatic materials, and their polymer chains tend to orient in the plane of the film / coating as it is formed. This creates a difference in the parallel and perpendicular refractive indices of the film (birefringence), resulting in optical retardation that can adversely affect display performance.

[0006] Furthermore, when polyimides are processed into electronic devices, they are often subjected to additional stresses in terms of temperature, environment, strain, etc. Such exposure can lead to the formation of defects or imperfections that render a particular film unusable in a given device. Not only can the polyimide film itself be damaged, but the entire device can become unusable, resulting in the need for rework, replacement, etc.

[0007] If polyimides are to find further application in the display market, solutions are needed that maintain desirable properties throughout processing while simultaneously improving light transmission and reducing birefringence, which leads to brown color and optical retardation. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, there is a continuing need for improved polymeric materials, such as polyimide films, that are suitable for use in electronic devices. [Means for solving the problem]

[0009] 1. A liquid composition comprising: (a) Formula I [ka] (In the formula, R a are the same or different in each occurrence and represent one or more tetracarboxylic acid moiety residues; R b are the same or different in each occurrence and represent one or more diamine residues. a polyamic acid having a repeating unit structure of (b) one or more phosphorus-containing additives; (c) a high-boiling aprotic solvent; A liquid composition is provided comprising:

[0010] Furthermore, Formula II [ka] (In the formula, R a are the same or different in each occurrence and represent one or more tetracarboxylic acid moiety residues; R b are the same or different in each occurrence and represent one or more diamine residues. A polyimide film comprising the repeating unit structure of the formula (I), further comprising the steps of: Provided is a polyimide film produced according to a method including, in sequence and without repetition, the steps of: coating a substrate with a polyamic acid solution containing one or more tetracarboxylic acid components and one or more diamine components in a high-boiling aprotic solvent; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals.

[0011] There is further provided a flexible alternative to glass in electronic devices, wherein the flexible alternative to glass is the polyimide film described above. Additionally provided is an electronic device having at least one layer comprising the above-described polyimide film.

[0012] Further provided are organic electronic devices, such as OLEDs, that include the flexible alternatives to glass disclosed herein.

[0013] The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as defined in the appended claims.

[0014] Embodiments are illustrated in the accompanying figures to aid in understanding the concepts presented herein. [Brief explanation of the drawings]

[0015] [Figure 1] Included is an illustration of one example of a polyimide film that can serve as a flexible replacement for glass. [Figure 2] Included is an illustration of one embodiment of an electronic device that includes a flexible replacement for glass. DETAILED DESCRIPTION OF THE INVENTION

[0016] Those skilled in the art will appreciate that objects in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the objects in the figures may be exaggerated relative to other objects to help improve understanding of the embodiments.

[0017] As described in detail below, polyamic acids having Formula I are provided.

[0018] Further provided is a liquid composition comprising: (a) a polyamic acid having Formula I; (b) one or more phosphorus-containing additives; and (c) a high-boiling aprotic solvent.

[0019] Further provided are polyimides whose repeating units have the structure of Formula II, described in detail below.

[0020] Also provided are one or more methods for producing a polyimide film, wherein the polyimide film has repeating units of Formula II:

[0021] There is further provided a flexible replacement for glass in electronic devices, wherein the flexible replacement for glass is a polyimide film having repeating units of Formula II. Further provided is an electronic device having at least one layer comprising a polyimide film having a repeating unit of Formula II.

[0022] Further provided are organic electronic devices, such as OLEDs, that include the flexible alternatives to glass disclosed herein.

[0023] Many aspects and embodiments have been described above, and are illustrative only, and not limiting. After reading this specification, skilled artisans will appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

[0024] Other features and advantages of any one or more embodiments will be apparent from the following detailed description and claims. The detailed description will first address definitions and clarification of terms, followed by the liquid composition, polyimide, method for making polyimide films, electronic devices, and finally, examples.

[0025] 1. Definitions and Explanations of Terms Before addressing the details of the embodiments below, some terms will be defined or clarified.

[0026] As used in "Definitions and Clarifications," R, R a , R b , R', R'' and any other variables are generic and may be the same or different from the variables defined in the formula.

[0027] The term "additive" is intended to mean a substance added to another substance to alter or improve the general qualities of the entire collection of components or to counteract an undesirable property. In some non-limiting embodiments, additives are used at concentrations much lower than the concentration of the main component of the composition or mixture.

[0028] The term "alignment layer" is intended to mean a layer of organic polymer in a liquid crystal device that aligns the molecules closest to each plate as a result of being rubbed against the LCD glass in one preferred direction during the LCD manufacturing process.

[0029] As used herein, the term "alkyl" includes branched and straight-chain saturated aliphatic hydrocarbon groups. Unless otherwise specified, the term is also intended to include cyclic groups. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, isobutyl, secbutyl, tertbutyl, pentyl, isopentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, isohexyl, and the like. The term "alkyl" further includes both substituted and unsubstituted hydrocarbon groups. In some embodiments, alkyl groups can be mono-, di-, and tri-substituted. An example of a substituted alkyl group is trifluoromethyl. Other substituted alkyl groups are formed with one or more of the substituents described herein. In certain embodiments, alkyl groups have 1 to 20 carbon atoms. In other embodiments, the groups have 1 to 6 carbon atoms. The term is intended to include heteroalkyl groups. Heteroalkyl groups can have 1 to 20 carbon atoms.

[0030] The term "aprotic" refers to a class of solvents that lack an acidic hydrogen atom and therefore cannot act as a hydrogen donor. Common aprotic solvents include alkanes, carbon tetrachloride (CCl4), benzene, dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), and many other solvents.

[0031] The term "aromatic compound" is intended to mean an organic compound containing at least one unsaturated cyclic group having 4n+2 delocalized π-electrons. The term is intended to encompass both aromatic compounds having only carbon and hydrogen atoms, and heteroaromatic compounds in which one or more of the carbon atoms in the cyclic group are replaced by another atom, such as nitrogen, oxygen, sulfur, etc.

[0032] The term "aryl" or "aryl group" refers to a moiety formed by removing one or more hydrogens ("H") or deuteriums ("D") from an aromatic compound. An aryl group can have a single ring (monocyclic) or multiple rings (bicyclic or higher) fused together or joined by covalent bonds. A "hydrocarbon aryl" has only carbon atoms in the aromatic ring(s). A "heteroaryl" has one or more heteroatoms in at least one aromatic ring. In some embodiments, a hydrocarbon aryl group has 6 to 60 ring carbon atoms, and in some embodiments, 6 to 30 ring carbon atoms. In some embodiments, a heteroaryl group has 4 to 50 ring carbon atoms, and in some embodiments, 4 to 30 ring carbon atoms.

[0033] The term "alkoxy" is intended to mean the group --OR, where R is alkyl.

[0034] The term "aryloxy" is intended to mean the group --OR, where R is aryl.

[0035] Unless otherwise specified, all groups can be substituted or unsubstituted. Optionally substituted groups, such as, but not limited to, alkyl or aryl, can be substituted with one or more substituents, which can be the same or different. Suitable substituents include alkyl, aryl, nitro, cyano, -N(R')(R ”), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl, siloxy, siloxane, thioalkoxy, -S(O)2-, -C(=O)-N(R')(R"), (R')(R")N-alkyl, (R')(R'')N-alkoxyalkyl, (R')(R'')N-alkylaryloxyalkyl, -S(O) s -aryl (wherein s=0 to 2) or -S(O) s -heteroaryl (where s=0-2). Each R' and R" is independently an optionally substituted alkyl, cycloalkyl, or aryl group. R' and R" together with the nitrogen atom to which they are attached can form a ring system in certain embodiments. Substituents may also be bridging groups.

[0036] The term "amine" is intended to mean a compound containing a basic nitrogen atom with a lone pair of electrons. The term "amino" refers to the functional group -NH2, -NHR, or -NR2, where R is the same or different in each occurrence and may be an alkyl or aryl group. The term "diamine" is intended to mean a compound containing two basic nitrogen atoms with associated lone pairs of electrons. The term "aromatic diamine" is intended to mean an aromatic compound having two amino groups. The term "bent diamine" is intended to mean a compound in which the two basic nitrogen atoms and associated lone pairs are bonded to the corresponding compound or functional group, for example, m-phenylenediamine: [ka] is intended to mean

[0037] The term "aromatic diamine residue" is intended to mean the moiety attached to two amino groups in an aromatic diamine. The term "aromatic diisocyanate residue" is intended to mean the moiety attached to two isocyanate groups in an aromatic diisocyanate compound. This is further exemplified below. [ka]

[0038] The terms "diamine residue" and "diisocyanate residue" are intended to mean moieties bonded to two amino groups or two isocyanate groups, respectively, which moieties may be aliphatic or aromatic.

[0039] The term "b*" is intended to refer to the b* axis in the CIELab color space, which represents the yellow / blue color opponent. Yellow is represented by a positive b* value, and blue is represented by a negative b* value. The measured b* value can be influenced by the solvent, especially since the choice of solvent can affect the measured color for materials exposed to high-temperature processing conditions. This can occur as a result of the inherent properties of the solvent and / or properties associated with low levels of impurities contained in various solvents. Specific solvents are often preselected to achieve the desired b* value for a particular application.

[0040] The term "birefringence" is intended to mean the difference in refractive index in different directions within a polymer film or coating. This term usually refers to the difference between the x-axis or y-axis (in-plane) and z-axis (out-of-plane) refractive indices.

[0041] The term "charge transport," when referring to a layer, material, component, or structure, is intended to mean that such layer, material, component, or structure facilitates the movement of such charge through the thickness of such layer, material, component, or structure with relative efficiency and low charge loss. Hole transport materials promote positive charges; electron transport materials promote negative charges. Although light-emitting materials may also have some charge transport properties, the term "charge transport layer, material, component, or structure" is not intended to include layers, materials, components, or structures whose primary function is light emission.

[0042] The term "compound" is intended to mean an uncharged substance composed of molecules further comprising atoms that cannot be separated from their corresponding molecules by physical means without breaking chemical bonds. This term is intended to include oligomers and polymers.

[0043] The term "coefficient of linear thermal expansion (CTE or α)" is intended to mean a parameter that defines the amount a material expands or contracts as a function of temperature. The coefficient of linear thermal expansion is expressed as change in length per degree Celsius, and is typically expressed in units of μm / m / °C or ppm / °C. α=(ΔL / L0) / ΔT The measured CTE values ​​disclosed herein are generated by known methods during the first or second heating scan. Understanding the relative expansion / contraction properties of materials can be an important consideration in the fabrication and / or reliability of electronic devices.

[0044] The term "dopant" is intended to mean a material, within a layer including a host material, that alters the electronic properties or the target wavelengths of radiation emission, reception, or filtering of that layer compared to the electronic properties or wavelengths of radiation emission, reception, or filtering of that layer in the absence of such material.

[0045] The term "electroactive," when referring to a layer or material, is intended to indicate a layer or material that electronically facilitates the operation of a device. Examples of electroactive materials include, but are not limited to, materials that conduct, inject, transport, or block charge (which can be either electrons or holes), or materials that exhibit a change in concentration of electron-hole pairs when emitting or receiving radiation. Examples of inactive materials include, but are not limited to, planarizing materials, insulating materials, and environmental barrier materials.

[0046] The term "tensile elongation" or "tensile strain" is intended to mean the percentage increase in length that occurs in a material before it breaks under an applied tensile stress, which can be measured, for example, by ASTM method D882.

[0047] The prefix "fluoro" is intended to indicate that one or more hydrogen atoms in the group have been replaced with fluorine.

[0048] The term "glass transition temperature (T g "Glass transition" is intended to mean the temperature at which a reversible change occurs in an amorphous polymer or in the amorphous regions of a semicrystalline polymer, where the material suddenly changes from a rigid, glassy, ​​or brittle state to a flexible or rubbery state. Microscopically, the glass transition occurs when the normally coiled, motionless polymer chains become free to rotate and pass through each other. T g can be measured using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), or dynamic mechanical analysis (DMA), or other methods.

[0049] The prefix "hetero" indicates that one or more carbon atoms have been replaced with a different atom. In some embodiments, the heteroatom is O, N, S, or a combination thereof.

[0050] The term "high boiling" is intended to indicate a boiling point above 130°C.

[0051] The term "host material" is intended to mean a material to which a dopant is added. The host material may or may not have electronic properties or the ability to emit, receive, or filter radiation. In some embodiments, the host material is present in a higher concentration.

[0052] The term "isothermal weight loss" is intended to mean the property of a material that is directly related to its isothermal stability. Isothermal weight loss is typically measured at a constant temperature of interest by thermogravimetric analysis (TGA). Materials with high thermal stability typically exhibit a very low percent isothermal weight loss at the required use or processing temperatures over a desired period of time, and therefore can be used in applications at these temperatures without significant loss of strength, outgassing, and / or structural changes.

[0053] The term "liquid composition" is intended to mean a liquid medium in which a material is dissolved to form a solution, dispersed to form a dispersion, or suspended to form a suspension or emulsion.

[0054] The term "parent material" is intended to mean a base upon which one or more layers are placed, for example, in forming an electronic device. Non-limiting examples include glass, silicon, and others.

[0055] The term "1% TGA weight loss" is intended to mean the temperature at which 1% of the original polymer weight is lost due to decomposition (elimination of absorbed water).

[0056] The term "optical retardation (or R TH ) is intended to mean the difference between the average in-plane refractive index and the out-of-plane refractive index (i.e., birefringence), which is then multiplied by the thickness of the film or coating. Typically, optical retardation is measured for a particular frequency of light and is reported in units of nanometers.

[0057] The terms "organic electronic device" or sometimes "electronic device" are intended herein to mean a device that includes one or more organic semiconductor layers or materials.

[0058] The term "particle content" is intended to mean the number or count of insoluble particles present in a solution. Measurement of particle content can be performed on the solution itself or on product materials (parts, films, etc.) prepared from these films. This property can be assessed using various optical methods.

[0059] The term "photoactive" refers to a material or layer that emits light when activated by an applied voltage (as in a light-emitting diode or chemical cell), emits light after absorbing a photon (as in a down-converting phosphor device), or responds to radiant energy (as in a photodetector or photovoltaic cell) to produce a signal with or without an applied bias voltage.

[0060] The term "plasma-enhanced chemical vapor deposition" or "PECVD" refers to a process that can deposit thin films of various materials onto a substrate at temperatures lower than those used in standard chemical vapor deposition (CVD) processes.

[0061] The term "polyamic acid solution" refers to a solution of a polymer containing amic acid units capable of intramolecular cyclization to form imide groups.

[0062] The term "polyimide" refers to condensation polymers resulting from the reaction of one or more difunctional carboxylic acid components with one or more primary diamines or diisocyanates. These contain the imide structure -CO-NR-CO- as a linear or heterocyclic unit along the main chain of the polymer backbone.

[0063] The term "satisfactory," when referring to a property or characteristic of a material, is intended to mean that the property or characteristic meets all requirements / demands for the material in use. For example, an isothermal weight loss of less than 1% in 3 hours at 350°C in nitrogen can be considered a non-limiting example of a "satisfactory" property in the context of the polyimide films disclosed herein.

[0064] The term "soft bake" is intended to mean a process commonly used in electronics manufacturing in which coated materials are heated to drive off solvents and solidify the film. Soft bake is typically performed on a hot plate or in a ventilated oven at temperatures between 90°C and 110°C in preparation for subsequent heat treatment of the coated layer or film.

[0065] The term "substrate" refers to a base material that may be either rigid or flexible and may include one or more layers of one or more materials, including, but not limited to, glass, polymer, metal, or ceramic materials, or combinations thereof. A substrate may or may not include electronic components, circuits, or conductive members.

[0066] The term "siloxane" refers to the group RSiORSi-, where R, which is the same or different at each occurrence, is H, C alkyl, fluoroalkyl, or aryl. In some embodiments, one or more carbons in the R alkyl group are replaced with Si.

[0067] The term "siloxy" refers to the group R3SiO-, where R, which is the same or different at each occurrence, is H, C1-20 alkyl, fluoroalkyl, or aryl.

[0068] The term "silyl" refers to the group RSi-, where R is the same or different at each occurrence and is H, C alkyl, fluoroalkyl, or aryl. In some embodiments, one or more carbons in the R alkyl group are replaced with Si.

[0069] The term "spin coating" is intended to mean a process used to deposit uniform thin films on flat substrates. Generally, a small amount of coating material is applied to the center of a substrate that is either rotating slowly or not rotating at all. The substrate is then spun at a specific speed to spread the coating material evenly by centrifugal force.

[0070] The term "laser particle counter testing" refers to a method used to evaluate the particle content of polyamic acid and other polymer solutions whereby a representative sample of the test solution is spin-coated onto a 5-inch silicon wafer and soft-baked / dried. The films so produced are evaluated for particle content by any number of standard measurement techniques, including laser particle detection, as known in the art.

[0071] The term "tensile modulus" is intended to mean a measure of the stiffness of a solid material that defines the initial relationship between stress (force per unit area) and strain (proportional deformation) in a material such as a film. A commonly used unit is gigapascals (GPa).

[0072] The term "tetracarboxylic acid component" is intended to mean any one or more of the following: tetracarboxylic acid, tetracarboxylic acid monoanhydride, tetracarboxylic acid dianhydride, tetracarboxylic acid monoester, and tetracarboxylic acid diester.

[0073] The term "tetracarboxylic acid moiety residue" is intended to mean the bonded moieties to the four carboxy groups of the tetracarboxylic acid moiety, as further exemplified below. [ka]

[0074] The term "transmittance" refers to the percentage of light of a given wavelength impinging on a film that passes through the film so as to be detectable on the other side. Light transmittance measurements in the visible region (380 nm to 800 nm) are particularly useful for characterizing film color properties, which are most important for understanding the in-use properties of the polyimide films disclosed herein.

[0075] The term "Yellowness Index (or YI)" refers to the degree of yellowness compared to a standard. A positive YI value indicates the presence and magnitude of yellow color. Materials with a negative YI appear bluish. It should also be noted that YI can be solvent-dependent, particularly for polymerization and / or curing processes performed at elevated temperatures. The magnitude of color introduced using DMAC as a solvent may differ from the magnitude of color introduced using, for example, NMP as a solvent. This can occur as a result of inherent properties of the solvent and / or properties related to low levels of impurities contained in various solvents. A particular solvent is often pre-selected to achieve a desired YI value for a particular application.

[0076] In structures where the substituent bond passes through one or more rings as shown below: [ka] It is meant that the substituent R may be attached at any available position on the ring or rings.

[0077] The phrase "adjacent to," when used to refer to layers in a device, does not necessarily mean that one layer is directly adjacent to another layer. On the other hand, the phrase "adjacent R groups" is used to refer to R groups that are next to each other in a chemical formula (i.e., R groups that are on atoms that are connected by a bond). Exemplary adjacent R groups are shown below: [ka]

[0078] Unless otherwise expressly stated or indicated in connection with use to the contrary, when an embodiment of the subject matter herein is stated or described as comprising, including, containing, containing, having, consisting of, or consisting of particular features or elements, one or more features or elements in addition to those expressly stated or described may be present in the embodiment. Although alternative embodiments of the disclosed subject matter herein may be described as consisting essentially of particular features or elements, in that embodiment, no features or elements are present therein that materially alter the principles of operation or distinguishing characteristics of the embodiment. Further alternative embodiments of the described subject matter herein may be described as consisting of particular features or elements, but in that embodiment, or in an intangible variation thereof, only the specifically stated or described features or elements are present.

[0079] Furthermore, unless expressly stated to the contrary, "or" means an inclusive "or" and not an exclusive "or." For example, a condition A "or" B is satisfied by any one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and A and B are both true (or exist).

[0080] Similarly, the use of "a" or "an" is used to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be interpreted to include one or at least one, and the singular also includes the plural unless it is clear that it has a different meaning.

[0081] The group numbers corresponding to the columns of the periodic table of elements are given in CRC Handbook of Chemistry and Physics, 81 st Uses the "New Notation" convention as found in Edition (2000-2001).

[0082] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a specific section is cited. In case of conflict, the present specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0083] To the extent not described herein, many details regarding specific materials, processing operations and circuitry are conventional and can be found in textbooks and other sources of information in organic light emitting diode display, photodetector, photovoltaic and semiconductor component technology.

[0084] 2.Liquid composition (a) Formula I [ka] (In the formula, R a are the same or different in each occurrence and represent one or more tetracarboxylic acid moiety residues; R b are the same or different in each occurrence and represent residues of one or more diamine moieties. (b) one or more phosphorus-containing additives; and (c) a high-boiling aprotic solvent. The liquid composition is also referred to herein as a "polyamic acid solution."

[0085] Examples of suitable phosphorus-containing additives are not particularly limited and are typically selected from the group consisting of organophosphorus compounds of P(III), P(V), and derivatives thereof. Non-limiting examples of P(III) organophosphorus compounds include phosphines (PR3, including alkyldiarylphosphines, bidentate alkyldiarylphosphines, bidentate triarylphosphines, dialkylarylphosphines, trialkylphosphines, and triarylphosphines), aminophosphines (PR2(NR2)), phosphinites (PR2(OR)), diaminophosphines (PR(NR2)2), phosphoamidites (PR(OR)(NR2)), phosphonites (PR(OR)2, including dialkylarylphosphonites and bidentate arylphosphonites), triamino-phosphines (P(NR2)3), phosphoro-diamidites (P(OR)(NR2)2), phosphoramidites (P(OR)2(NR2)), and phosphites (P(OR)3, including triarylphosphites and bidentate arylphosphites). Typically, in these P(III) compounds, R is the same or different in each occurrence and is selected from the group consisting of hydrogen, substituted or unsubstituted (C1-C30) alkyl, substituted or unsubstituted (C2-C30) alkenyl, substituted or unsubstituted (C5-C30) aryl, substituted or unsubstituted 5-30 membered heteroaryl, or CN; or may be joined to adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic (C5-C30) aliphatic or aromatic ring, a carbon atom of which may be replaced with at least one heteroatom selected from nitrogen, oxygen, sulfur, Si, PO, SO, SO2, and SeO2.

[0086] In some non-limiting embodiments of the P(III) organophosphorus compound, at least one of R is C1-C30 alkyl, and in some embodiments, all of R are C1-C30 alkyl.

[0087] Non-limiting examples of organophosphorus compounds of P(V) include phosphine oxides (PR3(O), including trialkylphosphine oxides and triarylphosphine oxides), phosphinates (PR2(O)(OR), including arylphosphinic acids and dialkylphosphinic acids), phosphinamides (PR2(O)(NR2)), phosphonates (PR(O)(OR)2, including trialkylphosphonates, triarylphosphonates, and dialkylarylphosphonates), phosphonamidates (PR(O)(OR)(NR2)), phosphonamides (PR(O)(NR2)2), phosphates (P(O)(OR)3, including alkylphosphoric acids), phosphoroamidates (P(O)(OR)2(NR2)), phosphorodiamidates (P(O)(OR)(NR2)2), and phosphoroamides (P(O)(NR2)3). Typically, in these P(V) compounds, R is the same or different in each occurrence and is selected from the group consisting of hydrogen, substituted or unsubstituted (C1-C30) alkyl, substituted or unsubstituted (C2-C30) alkenyl, substituted or unsubstituted (C5-C30) aryl, substituted or unsubstituted 5-30 membered heteroaryl, or CN; or may be joined to adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic (C5-C30) aliphatic or aromatic ring, a carbon atom of which may be replaced with at least one heteroatom selected from nitrogen, oxygen, sulfur, Si, PO, SO, SO2, and SeO2.

[0088] In some non-limiting embodiments of the organophosphorus compound of P(V), at least one of R is C1-C30 alkyl, and in some embodiments, all of R are C1-C30 alkyl.

[0089] Non-limiting examples of phosphorus-containing additives include tributylphosphine, trihexylphosphine, bis(2,4,4-trimethylpentyl)phosphinic acid, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, trihexylphosphine oxide, di-n-hexylphosphinic acid, hexyl dihexylphosphinate, di(2-ethylhexyl)phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, bis(2,4,4-trimethylpentyl)phosphinic acid, trioctylphosphine, bis[(2-diphenyl) 2-(diphenylphosphino)phenyl]ether, 1,3-bis(diphenylphosphino)propane, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, triphenylphosphine, rac-2-(di-tert-butylphosphino)-1,1'-binaphthyl, 2-(diphenylphosphino)biphenyl, 2,2'-bis(diphenylphosphino)biphenyl, 1,2-bis(di-2-pyridylphosphino)ethane, 4,6-bis(diphenylphosphino)phenoxazine, 9,9-dimethyl-4,5-bis(di-tert-butylphosphino ) xanthene, (di-tert-butylphosphino)biphenyl, tri-hexylphosphine, tri-1-naphthalenylphosphine, 2-di-tert-butylphosphino-2'-(N,N-dimethylamino)biphenyl, tert-butyldiphenylphosphine, trioctylphosphine oxide, triphenylphosphine oxide, triethylphosphine oxide, 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide, tris(2,4-di-t-butylphenyl)phosphite, diphenylphenylphosphonate, (Di-tert-butylphosphino)biphenyl, tetrakis(2,4-di-tert-butylphenyl)[1,1'-biphenyl]-4,4'-diylbis(phosphonite), trioctylphosphine oxide, (2R,2'R,5R,5'R)-1,1'-(1,2-ethanediyl)bis[2,5-diphenylphosphorane], bis[(2-diphenylphosphino)phenyl]ether, 4,6-bis(diphenylphosphino)dibenzofuran, diphenyl-4-pyrenylphosphine, 2,2'-bis(diphenylphosphino)benzophenone, 4,Examples include 5-bis(diphenylphosphino)-9,9-dimethylxanthene, tris(2,4-di-t-butylphenyl)phosphite, dioctylphenylphosphonate, diethyl 1-octylphosphonate, and tetrakis(2,4-di-tert-butylphenyl)[1,1'-biphenyl]-4,4'-diylbis(phosphonite).

[0090] In some embodiments of the liquid compositions disclosed herein, the one or more phosphorus-containing additives are present in the liquid composition at a concentration of 0.01 wt % to 10 wt %, in some non-limiting embodiments, 0.01 wt % to 5 wt %, 0.01 wt % to 2 wt %, in some non-limiting embodiments, 0.025 wt % to 1.5 wt %, in some non-limiting embodiments, 0.05 wt % to 1.0 wt %, in some non-limiting embodiments, 0.1 wt % to 0.75 wt %, in some non-limiting embodiments, 0.15 wt % to 0.4 wt %, and in some non-limiting embodiments, 0.2 wt % to 0.3 wt %.

[0091] In some embodiments of Formula I, R a represents a single tetracarboxylic acid component residue, in some embodiments two tetracarboxylic acid component residues, in some embodiments three tetracarboxylic acid residues, in some embodiments four tetracarboxylic acid residues, and in some embodiments five or more tetracarboxylic acid dianhydride residues.

[0092] Examples of suitable tetracarboxylic dianhydrides include, but are not limited to, pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic anhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-bisphenol A dianhydride (BPADA), Hydroquinone diphthalic anhydride (HQDEA), ethylene glycol bis(trimellitic anhydride) (TMEG-100), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (DTDA); 4,4'-bisphenol A dianhydride (BPADA), cyclobutane dianhydride (CBDA); 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride; 3-(carboxymethyl )-1,2,4-Cyclopentanetricarboxylic acid 1,4:2,3-dianhydride;Bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride;1,2,3,4-Cyclopentanetetracarboxylic acid dianhydride;1,2,4,5-Cyclohexanetetracarboxylic acid dianhydride;1,2,3,4-Tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride;1,3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride tricyclo[6.4.0.02,7]dodecane-1,8:2,7-tetracarboxylic dianhydride; meso-butane-1,2,3,4-tetracarboxylic dianhydride; 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydro-naphthalene-1,2-dicarboxylic anhydride; 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, and the like, and combinations thereof. These dianhydrides include alkyl, aryl, nitro, cyano, -N(R')(R ”), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl, siloxy, siloxane, thioalkoxy, -S(O)2-, -C(=O)-N(R')(R''), (R')(R'')N-alkyl, (R')(R'')N-alkoxyalkyl, (R')(R'')N-alkylaryloxyalkyl, -S(O) s -aryl (wherein s=0-2) or S(O) s -heteroaryl (where s=0-2). Each R' and R" is independently an optionally substituted alkyl, cycloalkyl, or aryl group. R' and R" together with the nitrogen atom to which they are attached can form a ring system in certain embodiments. Substituents may also be bridging groups. Halo substitution with one or more F atoms per tetracarboxylic dianhydride provides fluorinated embodiments of these species.

[0093] In some embodiments, the introduction of fluorine atoms into polyimides produces materials and films with properties more suited to the end-use applications disclosed herein. The high electronegativity of fluorine atoms can result in strong bonds between carbon atoms and fluorine atoms, imparting relatively high thermal and chemical stability to related fluorocarbon materials. Fluorine atoms can also enhance solubility, processability, and transparency in some embodiments, and can also aid in reducing the water absorption and dielectric constant of the resulting polyimides.

[0094] One strategy for incorporating fluorine into the liquid compositions and films disclosed herein is to incorporate fluorine into the tetracarboxylic acid moiety residue. aNon-limiting examples of suitable tetracarboxylic dianhydrides containing one or more F atoms per residue include, but are not limited to, 4,4'-hexafluoroisopropylidenebisphthalic dianhydride (6FDA), 1H-difuro[3,4-b:3',4'-i]xanthene 1,3,7,9(11H)-tetrone,11,11 bis(trifluoromethyl); 1H-difuro[3,4-b:3',4'-i]xanthene 1,3,7,9(11H)-tetrone ,11-phenyl-11(trifluoromethyl); 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7tetrone,4,8-bis(trifluoromethyl); 1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7tetrone,4,8-difluoro; 1H-difuro[3,4-b:3',4'-i]xanthene-1,3,7,9(11H)-tetrone,11-methyl-11(trifluoromethyl). These dianhydrides are alkyl, aryl, nitro, cyano, -N(R')(R ” ), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl, siloxy, siloxane, thioalkoxy, -S(O)2-, -C(=O)-N(R')(R''), (R')(R'')N-alkyl, (R')(R'')N-alkoxyalkyl, (R')(R'')N-alkylaryloxyalkyl, -S(O) s -aryl (wherein s=0-2) or S(O) s -heteroaryl (where s=0-2). Each R' and R" is independently an optionally substituted alkyl, cycloalkyl, or aryl group. R' and R" together with the nitrogen atom to which they are attached can form a ring system in certain embodiments. Substituents may also be bridging groups.

[0095] In some embodiments of Formula I, R arepresents one or more residues from a tetracarboxylic dianhydride selected from the group consisting of PMDA, BPDA, 6FDA, and BTDA. In some embodiments, it is a PMDA residue; in some embodiments, it is a BPDA residue; in some embodiments, it is a 6FDA residue; in some embodiments, it is a BTDA residue; in some embodiments, it is a PMDA residue, a BPDA residue, and a 6FDA residue; in some embodiments, it is a PMDA residue and a 6FDA residue; in some embodiments, it is a BPDA residue and a 6FDA residue; in some embodiments, it is a BTDA residue and a 6FDA residue.

[0096] In some embodiments of Formula I, R b represents a single diamine component residue, in some embodiments two diamine component residues, in some embodiments three diamine component residues, in some embodiments four diamine component residues, and in some embodiments five or more diamine component residues.

[0097] Examples of suitable diamines include, but are not limited to, p-phenylenediamine (PPD), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 3,3'-dimethyl-4,4'-diaminobiphenyl (o-tolidine), 3,3'-dihydroxy-4,4'-diaminobiphenyl (HAB), 9,9'-bis(4-aminophenyl)fluorene (FDA), o-tolidine sulfone (TSN), 2,3,5,6-tetramethyl-1,4-phenylenediamine (TMPD), 2,4-diamino- 1,3,5-trimethylbenzene (DAM), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4'-methylenedianiline (MDA), 4,4'-[1,3-phenylenebis(1-methyl-ethylidene)]bisaniline (Bis-M), 4,4'-[1,4-phenylenebis(1-methyl-ethylidene)]bisaniline (Bis-P), 4,4'-oxydianiline (4,4'-ODA), m-phenylenediamine (MPD), 3,4'-oxydianiline (3,4'-ODA) ), 3,3'-diaminodiphenyl sulfone (3,3'-DDS), 4,4'-diaminodiphenyl sulfone (4,4'-DDS), 4,4'-diaminodiphenyl sulfide (ASD), 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone (m-BAPS), 1,4'-bis(4-aminophenoxy)benzene (TPE-Q), 1,3'-bis(4-aminophenoxy)benzene (TPE-R), 1,3'-bis( 4-aminophenoxy)benzene (APB-133), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-diaminobenzanilide (DABA), methylenebis(anthranilic acid) (MBAA), 1,3'-bis(4-aminophenoxy)-2,2-dimethylpropane (DANPG), 1,5-bis(4-aminophenoxy)pentane (DA5MG), 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (TMMDA), and the like, and combinations thereof.

[0098] These diamines include alkyl, aryl, nitro, cyano, -N(R')(R” ), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl, siloxy, siloxane, thioalkoxy, -S(O)2-, -C(=O)-N(R')(R''), (R')(R'')N-alkyl, (R')(R'')N-alkoxyalkyl, (R')(R'')N-alkylaryloxyalkyl, -S(O) s -aryl (wherein s=0-2) or S(O) s -heteroaryl (where s = 0-2). Each R' and R" is independently an optionally substituted alkyl, cycloalkyl, or aryl group. R' and R" together with the nitrogen atom to which they are attached can form a ring system in certain embodiments. The substituents may also be bridging groups. As explained above, the incorporation of fluorine into the liquid compositions disclosed herein can, in some embodiments, result in the production of polyimide films with superior thermal, optical, and other properties for the disclosed applications. Halo substitution with one or more F atoms per diamine affords fluorinated embodiments of these species, and thus represents one general synthetic strategy for incorporating fluorine.

[0099] One or more R bAdditional examples of suitable diamines containing one or more F atoms per residue include, but are not limited to, 2,2'-bis(trifluoromethyl)benzidine (22TFMB or TFMB), 3,3'-bis(trifluoromethyl)benzidine (33TFMB), 2,2'-bis[4-(4-aminophenoxyphenyl)]hexafluoropropane (HFBAPP), 2,2-bis(4-aminophenyl)hexafluoropropane (Bis-A)-AF), 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF), 2,2-bis(4-amino ... , 2-bis(3-amino-4-methylphenyl)hexafluoropropane (Bis-AT-AF), 1,4-bis(2-trifluoromethyl-4-aminophenoxy)benzene (p-6FAPB), 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6BFBAPB), N,N'-(2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl)bis(4-aminobenzamide) (AB-TFMB), 9,9-bis(4-amino-3-fluorophenyl)fluorene, and the like, and combinations thereof. These diamines may be alkyl, aryl, nitro, cyano, -N(R')(R ” )), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl, siloxy, siloxane, thioalkoxy, -S(O)2-, -C(=O)-N(R')(R''), (R')(R'')N-alkyl, (R')(R'')N-alkoxyalkyl, (R')(R'')N-alkylaryloxyalkyl, -S(O) s -aryl (wherein s=0-2) or S(O) s-heteroaryl (where s=0-2). Each R' and R" is independently an optionally substituted alkyl, cycloalkyl, or aryl group. R' and R" together with the nitrogen atom to which they are attached can form a ring system in certain embodiments. Substituents may also be bridging groups.

[0100] In some embodiments of Formula I, R b represents one or more residues from a diamine selected from the group consisting of PPD, MPD, TFMB, and Bis-A-AF. In some embodiments, it is a PPD residue; in some embodiments, it is an MPD residue; in some embodiments, it is a TFMB residue; in some embodiments, it is a Bis-A-AF residue; in some embodiments, it is a PPD residue, an MPD residue, and a TFMB residue; in some embodiments, it is a PPD residue and a TFMB residue; in some embodiments, it is an MPD residue and a TFMB residue; in some embodiments, it is a Bis-A-AF residue and a TFMB residue.

[0101] Additional non-limiting examples of suitable tetracarboxylic dianhydrides and diamines are described in, for example, U.S. Patent Application Publication No. 2020-0140615, WO 2020 / 033471, WO 2020 / 219411, U.S. Patent Application Publication No. 2020-0216614, U.S. Patent Application Publication No. 2020-0172675, WO 2019 / 246233, and the like. and those described in U.S. Patent Application Publication No. 2021-0017335, WO 2019 / 222304, WO 2019 / 246235, WO 2020 / 018621, WO 2020 / 033475, WO 2020 / 018617, and WO 2020 / 033480. Those skilled in the art will recognize that these disclosures describe dianhydrides, diamines, or both, and that in some cases fluorine substitution is present.

[0102] The benefits realized from using the liquid compositions disclosed herein to produce clear or light-colored polyimide films may, in some embodiments, be significantly greater than those that may be realized with more conventional formulations used to produce brown polyimides. That is, the use of fluorine-containing tetracarboxylic acid moiety residues and / or diamine moiety residues as components of a liquid composition that also includes a phosphorus-containing additive can result in surprising and unexpected improvements in the thermal, optical, mechanical, and other properties of the associated polyimide films.

[0103] In some non-limiting embodiments of the liquid compositions disclosed herein, R a contains one or more F atoms per tetracarboxylic acid moiety residue. In some non-limiting embodiments of the liquid compositions disclosed herein, R b contains one or more F atoms per tetracarboxylic acid moiety residue. In some non-limiting embodiments of the liquid compositions disclosed herein, R a and R b One or more of the following may contain one or more F atoms per residue:

[0104] While the use of fluorine-containing components may not be limiting in this regard, any strategy known in the art for producing thin or lighter colored polyimides may similarly benefit from the inclusion of the phosphorus-containing additives disclosed herein. Non-limiting examples of such strategies include the incorporation of aliphatic moieties, flexible groups, and others known to those skilled in the art. These liquid compositions for clear or light colored polyimide films that include the phosphorus-containing additives disclosed herein may similarly provide surprising and unexpected improvements in the thermal, optical, mechanical, and other properties of the associated polyimide films relative to their brown counterparts.

[0105] In some non-limiting embodiments of Formula I, the moiety resulting from the monoanhydride monomer is present as an end-capping group.

[0106] In some non-limiting embodiments, the monoanhydride monomer is selected from the group consisting of phthalic anhydride and the like and derivatives thereof.

[0107] In some non-limiting embodiments, the monoanhydride is present in an amount up to 5 mole % of the total tetracarboxylic acid composition.

[0108] In some non-limiting embodiments of Formula I, the moiety resulting from the monoamine monomer is present as an end-capping group.

[0109] In some non-limiting embodiments, the monoamine monomer is selected from the group consisting of aniline and the like and derivatives thereof.

[0110] In some non-limiting embodiments, the monoamine is present in an amount up to 5 mole percent of the total amine composition.

[0111] In some embodiments, the polyamic acid has a weight average molecular weight (M) based on gel permeation chromatography using polystyrene standards of greater than 100,000, in some non-limiting embodiments greater than 150,000, in some non-limiting embodiments greater than 200,000, in some non-limiting embodiments greater than 250,000, in some non-limiting embodiments greater than 300,000, in some non-limiting embodiments from 100,000 to 400,000, in some non-limiting embodiments from 200,000 to 400,000, in some non-limiting embodiments from 250,000 to 350,000, and in some non-limiting embodiments from 200,000 to 300,000. W )

[0112] Any of the above embodiments for polyamic acids can be combined with one or more of the other embodiments, as long as they do not contradict each other. For example, R a In embodiments where R represents a PMDA residue, b represents the formula TFMB residue.

[0113] In some non-limiting embodiments of the liquid compositions disclosed herein, the high boiling point aprotic solvent has a boiling point of 150°C or greater, in some non-limiting embodiments, 175°C or greater, and in some non-limiting embodiments, 200°C or greater.

[0114] In some non-limiting embodiments of the liquid compositions disclosed herein, the high-boiling aprotic solvent is a polar solvent. In some non-limiting embodiments, the solvent has a dielectric constant greater than 20.

[0115] Some examples of high boiling point aprotic solvents include, but are not limited to, N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), dimethylformamide (DMF), γ-butyrolactone, dibutyl carbitol, butyl carbitol acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and the like, and combinations thereof.

[0116] In some non-limiting embodiments of the liquid compositions disclosed herein, the solvent is selected from the group consisting of NMP, DMAc, and DMF. In some non-limiting embodiments of the liquid compositions disclosed herein, the solvent is NMP, in some non-limiting embodiments, DMAc, and in some non-limiting embodiments, DMF.

[0117] In some non-limiting embodiments of the liquid compositions disclosed herein, the solvent is gamma butyrolactone, in some non-limiting embodiments dibutyl carbitol, in some non-limiting embodiments butyl carbitol acetate, in some non-limiting embodiments diethylene glycol monoethyl ether acetate, and in some non-limiting embodiments propylene glycol monoethyl ether acetate.

[0118] In some embodiments, two or more of the above-specified high boiling aprotic solvents are used in the liquid composition.

[0119] In some embodiments, an additional co-solvent is used in the liquid composition.

[0120] The polyamic acid solution may optionally further contain any one of several additives, such as antioxidants, heat stabilizers, adhesion promoters, coupling agents (e.g., silanes), inorganic fillers, or various toughening agents, so long as they do not adversely affect the desired polyimide properties.

[0121] In some non-limiting embodiments of the liquid compositions disclosed herein, the solids content is at least 10% by weight, in some non-limiting embodiments at least 12% by weight, and in some non-limiting embodiments at least 15% by weight. In some non-limiting embodiments, the solids content is 10-20% by weight.

[0122] In some non-limiting embodiments of the liquid compositions disclosed herein, the viscosity is at least about 3000 cps, in some non-limiting embodiments at least about 5,000 cps, and in some non-limiting embodiments at least about 10,000 cps.

[0123] The liquid compositions comprising the polyamic acid solutions disclosed herein can be prepared using a variety of available methods for the introduction of the components (i.e., monomers, additives, and solvents). Some methods for producing liquid compositions comprising polyamic acid solutions include the following: (a) A method in which the diamine component and the dianhydride component are premixed together and then added portionwise to the solvent while the mixture is being stirred. (b) A method in which the solvent is added to a stirred mixture of the diamine and dianhydride components (as opposed to (a) above). (c) A method in which the diamine is dissolved exclusively in a solvent and then the dianhydride is added to it in a ratio that makes it possible to control the reaction rate. (d) A method in which the dianhydride component is dissolved exclusively in a solvent and then the amine component is added thereto in a ratio that makes it possible to control the reaction rate. (e) A method in which the diamine component and the dianhydride component are dissolved separately in a solvent and then these solutions are mixed in a reactor. (f) A process in which a polyamic acid containing an excess of an amine component and another polyamic acid containing an excess of a dianhydride component are preformed and then reacted with each other in a reactor in a manner that allows for the preparation of, inter alia, non-random or block copolymers. (g) A method in which a specific portion of the amine component and dianhydride component are reacted first, followed by the remaining diamine component, or vice versa. (h) A process in which the components are added, partially or as a whole, in any order to any part or all of the solvent, and further in which any part or all of the components may be added as a solution in any part or all of the solvent. (i) One of the dianhydride components is first reacted with one of the diamine components to form a first polyamic acid. The other dianhydride component is then reacted with the other amine component to form a second polyamic acid. The polyamic acids are then combined in one of several ways prior to film formation.

[0124] One or more phosphorus-containing additives can be added to the polyamic acid solution either before or after the polymerization step initiated above. In some non-limiting embodiments, a polyamic acid solution composition containing one or more phosphorus-containing additives can be obtained by first introducing the phosphorus-containing additives into a solvent and stirring it for a preselected period of time, which can be greater than 2 hours, greater than 4 hours in some non-limiting embodiments, greater than 8 hours in some non-limiting embodiments, greater than 10 hours, greater than 15 hours in some non-limiting embodiments, greater than 20 hours, greater than 25 hours in some non-limiting embodiments, or greater than 30 hours in some non-limiting embodiments. One or more tetracarboxylic acid components and one or more diamine components disclosed herein are then introduced to the solvent / additive mixture in this "pretreatment" protocol.

[0125] In another non-limiting embodiment, the polyamic acid solution composition containing one or more phosphorus-containing additives can be obtained by first adding one or more tetracarboxylic acid components and one or more diamine components to a selected solvent to allow formation of a polyamic acid solution, and finally introducing one or more phosphorus-containing additives, which is sometimes referred to as "post-treatment."

[0126] Generally speaking, a liquid composition comprising polyamic acid can be obtained from any one of the methods for preparing a polyamic acid solution disclosed above.

[0127] The liquid composition can then be optionally filtered one or more times to reduce particle content. Polyimide films produced from such filtered solutions exhibit a reduced number of defects, which can result in superior performance in the electronics applications disclosed herein. Evaluation of filtration efficiency can be performed by laser particle counter testing, in which a representative sample of the polyamic acid solution is cast onto a 5-inch silicon wafer. After soft baking / drying, the film is evaluated for particle content by any number of laser particle counting techniques on equipment commercially available and known in the art.

[0128] In some non-limiting embodiments, the liquid composition is prepared and filtered to have a particle content of less than 40 particles, in some non-limiting embodiments, less than 30 particles, in some non-limiting embodiments, less than 20 particles, in some non-limiting embodiments, less than 10 particles, in some non-limiting embodiments, between 2 and 8 particles, and in some non-limiting embodiments, between 4 and 6 particles, as measured by laser particle counter testing.

[0129] An exemplary preparation of a liquid composition containing a polyamic acid solution is provided in the Examples.

[0130] The overall polyamic acid composition can be represented by notations commonly used in the art, for example, a polyamic acid having a tetracarboxylic acid component that is 100% ODPA and a diamine component that is 90 mole % Bis-P and 10 mole % TFMB is represented as follows: ODPA / / Bis-P / TFMB 100 / / / 90 / 10.

[0131] 3. Polyimide film A polyimide film is provided which is produced from the liquid composition described above.

[0132] The polyimide may be represented by Formula II [ka] (In the formula, R a are the same or different in each occurrence and represent one or more tetracarboxylic acid moiety residues; R b are the same or different in each occurrence and represent one or more diamine residues. The polyimide film has a repeating unit structure of the formula: The polyamic acid film is produced by a method including, in order and without repetition, the steps of: coating a substrate with a polyamic acid solution containing one or more tetracarboxylic acid components and one or more diamine components in a high-boiling aprotic solvent; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals.

[0133] R in Formula I a and R b All of the above-described embodiments of R a and R b applies equally to

[0134] Polyimide films are produced by coating the liquid composition onto a substrate and then imidizing it. This can be accomplished by a thermal conversion process or a chemical conversion process. Any known coating method can be used.

[0135] Some fluorinated diamines are known to have low reactivity. To form polyimide films with sufficient molecular weight using these low-reactivity diamines, multiple polymerization steps are used. Typically, a polyamic acid solution is prepared using the low-reactivity diamine, the solution is coated and then imidized, and the imidized product is dissolved, recoated, and re-imidized. Additional dissolving, recoating, and re-imidization steps are repeated several times.

[0136] In some non-limiting embodiments of the polyimide film, the polyimide polymer has a weight average molecular weight (M) based on gel permeation chromatography using polystyrene standards of greater than 100,000, in some non-limiting embodiments greater than 150,000, in some non-limiting embodiments greater than 200,000, in some non-limiting embodiments greater than 250,000, in some non-limiting embodiments greater than 300,000, in some non-limiting embodiments between 100,000 and 400,000, in some non-limiting embodiments between 200,000 and 400,000, in some non-limiting embodiments between 250,000 and 350,000, and in some non-limiting embodiments between 200,000 and 300,000. W )

[0137] In some non-limiting embodiments of the polyimide film, the in-plane coefficient of thermal expansion (CTE) is less than 45 ppm / °C, in some non-limiting embodiments less than 30 ppm / °C, in some non-limiting embodiments less than 20 ppm / °C, in some non-limiting embodiments less than 15 ppm / °C, in some non-limiting embodiments 0 ppm / °C to 15 ppm / °C, in some non-limiting embodiments 0 ppm / °C to 10 ppm / °C, and in some non-limiting embodiments 4 ppm / °C to 7 ppm / °C, from 50°C to 250°C.

[0138] In some embodiments of the polyimide film, the in-plane coefficient of thermal expansion (CTE) is less than 45 ppm / °C, in some non-limiting embodiments less than 30 ppm / °C, in some non-limiting embodiments less than 20 ppm / °C, in some non-limiting embodiments less than 15 ppm / °C, in some non-limiting embodiments between 0 ppm / °C and 15 ppm / °C, in some non-limiting embodiments between 0 ppm / °C and 10 ppm / °C, and in some non-limiting embodiments between 4 ppm / °C and 8 ppm / °C, from 50°C to 300°C.

[0139] In some embodiments of the polyimide film, the in-plane coefficient of thermal expansion (CTE) is less than 45 ppm / °C, in some non-limiting embodiments less than 30 ppm / °C, in some non-limiting embodiments less than 20 ppm / °C, in some non-limiting embodiments less than 15 ppm / °C, in some non-limiting embodiments 0 ppm / °C to 15 ppm / °C, in some non-limiting embodiments 0 ppm / °C to 10 ppm / °C, and in some non-limiting embodiments 3 ppm / °C to 9 ppm / °C, from 50°C to 350°C.

[0140] In some embodiments of the polyimide film, the in-plane coefficient of thermal expansion (CTE) is less than 45 ppm / °C, in some non-limiting embodiments less than 30 ppm / °C, in some non-limiting embodiments less than 20 ppm / °C, in some non-limiting embodiments less than 15 ppm / °C, in some non-limiting embodiments between 0 ppm / °C and 15 ppm / °C, and in some non-limiting embodiments between 6 ppm / °C and 12 ppm / °C, from 50°C to 400°C.

[0141] In some embodiments of the polyimide film, the in-plane coefficient of thermal expansion (CTE) is less than 45 ppm / °C, in some non-limiting embodiments less than 30 ppm / °C, in some non-limiting embodiments less than 20 ppm / °C, in some non-limiting embodiments less than 15 ppm / °C, in some non-limiting embodiments between 0 ppm / °C and 15 ppm / °C, and in some non-limiting embodiments between 8 ppm / °C and 14 ppm / °C, from 50°C to 450°C.

[0142] In some non-limiting embodiments of the polyimide film, the glass transition temperature (T g ) is greater than 250°C, in some embodiments greater than 300°C, and in some embodiments greater than 350°C for polyimide films cured at temperatures greater than 300°C.

[0143] In some non-limiting embodiments of the polyimide film, the glass transition temperature (T g ) is greater than 400°C, in some embodiments greater than 410°C, and in some embodiments greater than 450°C for polyimide films cured at temperatures greater than 375°C.

[0144] In some non-limiting embodiments of the polyimide film, the glass transition temperature (T g ) is greater than 430°C, in some embodiments greater than 450°C, and in some embodiments greater than 480°C for polyimide films cured at temperatures greater than 400°C.

[0145] In some non-limiting embodiments of the polyimide film, the 0.5% TGA weight loss temperature is greater than 350°C, in some non-limiting embodiments greater than 400°C, in some non-limiting embodiments greater than 450°C, in some non-limiting embodiments greater than 500°C, and in some non-limiting embodiments greater than 550°C.

[0146] In some non-limiting embodiments, the polyimide film has a 1% TGA weight loss temperature greater than 350°C, greater than 400°C, greater than 450°C, greater than 500°C, and greater than 550°C.

[0147] In some non-limiting embodiments of the polyimide film, the tensile modulus is from 1.5 GPa to 15.0 GPa, in some non-limiting embodiments from 1.5 GPa to 12.0 GPa, and in some non-limiting embodiments from 3 GPa to 8 GPa.

[0148] In some non-limiting embodiments, the polyimide film has a tensile strength of 100 MPa to 250 MPa, in some non-limiting embodiments, 150 MPa to 225 MPa, and in some non-limiting embodiments, 175 MPa to 200 MPa.

[0149] In some non-limiting embodiments of the polyimide film, the elongation at break is greater than 10%, in some non-limiting embodiments greater than 15%, in some non-limiting embodiments greater than 20%, and in some non-limiting embodiments greater than 25%.

[0150] In some non-limiting embodiments of the polyimide film, the optical retardation at 550 nm is less than 500, in some non-limiting embodiments less than 200, and in some non-limiting embodiments less than 150.

[0151] In some non-limiting embodiments of the polyimide film, the birefringence at 633 nm is less than 0.15, in some embodiments less than 0.10, and in some non-limiting embodiments less than 0.05.

[0152] In some non-limiting embodiments of the polyimide film, the haze is less than 1.0%, in some non-limiting embodiments, less than 0.5%, and in some non-limiting embodiments, less than 0.25%.

[0153] In some non-limiting embodiments of the polyimide film, b* is less than 10, in some non-limiting embodiments, less than 7.5, in some non-limiting embodiments, less than 5, and in some non-limiting embodiments, less than 3. In some non-limiting embodiments of the polyimide film, YI is less than 20, in some non-limiting embodiments, less than 15, in some non-limiting embodiments, less than 10, and in some non-limiting embodiments, less than 5.

[0154] In some non-limiting embodiments of the polyimide film, the transmittance at 400 nm is greater than 40%, in some non-limiting embodiments greater than 50%, and in some non-limiting embodiments greater than 60%.

[0155] In some non-limiting embodiments of the polyimide film, the transmittance at 430 nm is greater than 60%, and in some non-limiting embodiments, greater than 70%.

[0156] In some non-limiting embodiments of the polyimide film, the transmittance at 450 nm is greater than 70%, and in some non-limiting embodiments, greater than 80%.

[0157] In some non-limiting embodiments of the polyimide film, the transmittance at 550 nm is greater than 70%, and in some non-limiting embodiments, greater than 80%.

[0158] In some non-limiting embodiments of the polyimide film, the transmittance at 750 nm is greater than 70%, in some non-limiting embodiments greater than 80%, and in some non-limiting embodiments greater than 90%.

[0159] In some non-limiting embodiments of the polyimide film, the average transmittance from 380 nm to 780 nm is greater than 70%, in some non-limiting embodiments greater than 80%, and in some non-limiting embodiments greater than 90%.

[0160] Any of the above-described embodiments for polyimide films can be combined with one or more other embodiments, as long as they are not mutually exclusive.

[0161] Polyimide films are prepared from polyamic acid solutions by chemical or thermal conversion processes. The polyimide films disclosed herein, particularly when used as flexible replacements for glass in electronic devices, are prepared by thermal or modified thermal conversion processes as opposed to chemical conversion processes.

[0162] Chemical conversion processes are described in U.S. Patent Nos. 5,166,308 and 5,298,331, which are incorporated by reference in their entireties. In such processes, conversion chemicals are added to a polyamic acid solution. Conversion chemicals found to be useful in the present invention include, but are not limited to, (i) one or more dehydrating agents, such as fatty acid anhydrides (e.g., acetic anhydride) and acid anhydrides; and (ii) one or more catalysts, such as aliphatic tertiary amines (e.g., triethylamine), tertiary amines (e.g., dimethylaniline), and heterocyclic tertiary amines (e.g., pyridine, picoline, isoquinoline). The acid anhydride used to dehydrate the material is typically used in slight molar excess over the amount of amic acid groups present in the polyamic acid solution. The amount of acetic anhydride used is typically about 2.0 to 3.0 moles per equivalent of polyamic acid. Generally, an equivalent amount of tertiary amine catalyst is used.

[0163] The thermal conversion process may or may not use a converting chemical (i.e., a catalyst) to convert the cast polyamic acid solution to a polyimide. If a converting chemical is used, the process may be considered a modified thermal conversion process. In both types of thermal conversion processes, only thermal energy is used to heat the film both to dry the film of solvent and to carry out the imidization reaction. Generally, thermal conversion processes with or without a converting catalyst are used to produce the polyimide films disclosed herein.

[0164] Specific process parameters are preselected with the understanding that it is not just the film composition that produces the properties of interest. Rather, the cure temperature and temperature ramp profile also play an important role in achieving the most desirable properties for the intended uses disclosed herein. The polyamic acid must be imidized at a maximum temperature that is at or above the temperature of any subsequent processing steps (e.g., deposition of inorganic or other layers required to produce a functional display), but below the temperature at which significant thermal decomposition / discoloration of the polyimide occurs. It should also be mentioned that an inert atmosphere is generally preferred when particularly high processing temperatures are used for imidization.

[0165] For the polyamic acids / polyimides disclosed herein, when subsequent processing temperatures above 300°C are required, temperatures between 300°C and 320°C are typically used. In some non-limiting embodiments where subsequent processing temperatures are higher, temperatures above 320°C are used, in some non-limiting embodiments, temperatures above 350°C are used, in some non-limiting embodiments, temperatures above 400°C are used, and in some non-limiting embodiments, temperatures above 450°C are used. Selection of the appropriate curing temperature allows for a fully cured polyimide that achieves the best balance of thermal and mechanical properties. Due to this very high temperature, an inert atmosphere is required. Typically, an oxygen level in the oven of less than 100 ppm should be used. Very low oxygen levels allow the highest curing temperatures to be used without significant degradation / discoloration of the polymer. Catalysts that accelerate the imidization process are effective in achieving higher levels of imidization at cure temperatures of about 200°C to 300°C. This approach allows for the T of polyimides to be improved. g It may optionally be used when flexible devices are made with an upper cure temperature below .

[0166] The amount of time in each latent cure step is also an important process consideration. Generally, the time used for the highest temperature cure should be kept to a minimum. For a 320°C cure, for example, the cure time can be up to an hour or so under an inert atmosphere, but at higher cure temperatures, this time should be reduced to avoid thermal degradation. Generally speaking, higher temperatures will dictate shorter times. Those skilled in the art will recognize the balance between temperature and time to optimize the properties of the polyimide for a particular end use.

[0167] In some non-limiting embodiments, the liquid composition is converted into a polyimide film via a thermal conversion process.

[0168] In some non-limiting embodiments of the thermal conversion process, the polyamic acid solution is coated onto the substrate such that the resulting film has a soft-baked thickness of less than 50 μm, in some non-limiting embodiments, less than 40 μm, in some non-limiting embodiments, less than 30 μm, in some non-limiting embodiments, less than 20 μm, in some non-limiting embodiments, between 10 μm and 20 μm, in some non-limiting embodiments, between 15 μm and 20 μm, and in some non-limiting embodiments, 18 μm. In some non-limiting embodiments of the thermal conversion process, the polyamic acid solution is coated onto the substrate such that the resulting film has a soft-baked thickness of less than 10 μm.

[0169] In some non-limiting embodiments of the thermal conversion process, the coated workpiece is soft-baked on a hotplate in proximity mode, where nitrogen gas is used to hold the coated workpiece directly above the hotplate. In some non-limiting embodiments of the thermal conversion process, the coated workpiece is soft-baked on a hotplate in full-contact mode, where the coated workpiece is in direct contact with the hotplate surface. In some non-limiting embodiments of the thermal conversion process, the coated workpiece is soft-baked on a hotplate using a combination of proximity and full-contact modes.

[0170] In some non-limiting embodiments of the thermal conversion process, the coated substrate is soft baked using a hot plate set at 80°C, in some non-limiting embodiments 90°C, in some non-limiting embodiments 100°C, in some non-limiting embodiments 110°C, in some non-limiting embodiments 120°C, in some non-limiting embodiments 130°C, and in some non-limiting embodiments 140°C.

[0171] In some non-limiting embodiments of the thermal conversion process, the coated substrate is soft baked for a total time of more than 10 minutes, in some non-limiting embodiments less than 10 minutes, in some non-limiting embodiments less than 8 minutes, in some non-limiting embodiments less than 6 minutes, in some non-limiting embodiments 4 minutes, in some non-limiting embodiments less than 4 minutes, and in some non-limiting embodiments less than 2 minutes.

[0172] In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at two preselected temperatures for two preselected time intervals, which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at three preselected temperatures for three preselected time intervals, which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at four preselected temperatures for four preselected time intervals, which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at five preselected temperatures for five preselected time intervals, which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at six preselected temperatures for six preselected time intervals, which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at seven preselected temperatures for seven preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at eight preselected temperatures for eight preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at nine preselected temperatures for nine preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the thermal conversion process, the soft-baked coated base material is then cured at ten preselected temperatures for ten preselected time intervals, each of which can be the same or different.

[0173] In some non-limiting embodiments of the thermal conversion process, the preselected temperature is greater than 80°C, in some non-limiting embodiments, 100°C, in some non-limiting embodiments, greater than 100°C, in some non-limiting embodiments, 150°C, in some non-limiting embodiments, greater than 150°C, in some non-limiting embodiments, 200°C, in some non-limiting embodiments, greater than 200°C, in some non-limiting embodiments, greater than 250°C, in some non-limiting embodiments, greater than 250°C, in some non-limiting embodiments, greater than 300°C, in some non-limiting embodiments, greater than 300°C, in some non-limiting embodiments, greater than 350°C, in some non-limiting embodiments, greater than 350°C, in some non-limiting embodiments, greater than 400°C, in some non-limiting embodiments, greater than 400°C, in some non-limiting embodiments, greater than 450°C, and in some non-limiting embodiments, greater than 450°C.

[0174] In some non-limiting embodiments of the thermal conversion process, one or more of the preselected time intervals is 2 minutes, in some non-limiting embodiments, 5 minutes, in some non-limiting embodiments, 10 minutes, in some non-limiting embodiments, 15 minutes, in some non-limiting embodiments, 20 minutes, in some non-limiting embodiments, 25 minutes, in some non-limiting embodiments, 30 minutes, in some non-limiting embodiments, 35 minutes, in some non-limiting embodiments, 40 minutes, in some non-limiting embodiments, 45 minutes, in some non-limiting embodiments, 50 minutes, in some non-limiting embodiments, 55 minutes, in some non-limiting embodiments, 60 minutes, in some non-limiting embodiments, greater than 60 minutes, in some non-limiting embodiments, between 2 minutes and 60 minutes, in some limiting embodiments, between 2 minutes and 90 minutes, and in some non-limiting embodiments, between 2 minutes and 120 minutes.

[0175] In some embodiments of the thermal conversion process, a method for producing a polyimide film comprises, in order, the following steps: coating a substrate with a liquid composition comprising a polyamic acid; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications such as those disclosed herein.

[0176] In some embodiments of the thermal conversion process, a method for producing a polyimide film comprises, in order, the following steps: coating a substrate with a liquid composition comprising a polyamic acid; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications such as those disclosed herein.

[0177] In some embodiments of the thermal conversion process, a method for producing a polyimide film comprises, in order, the following steps: coating a substrate with a liquid composition comprising a polyamic acid solution; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications such as those disclosed herein.

[0178] Typically, the liquid composition / polyimide disclosed herein is coated and cured on a supporting glass substrate to facilitate processing through the remainder of the display manufacturing process. At some point during the process, as determined by the display manufacturer, the polyimide coating is removed from the supporting glass substrate by mechanical or laser peeling processes. These processes separate the polyimide as a film with the deposited display layers from the glass, allowing for flexible formats. Often, this polyimide film with the deposited layers is then bonded to a thicker, yet still flexible, plastic film to provide support for subsequent fabrication of the display.

[0179] A modified thermal conversion process is also provided in which the conversion catalyst generally causes the imidization reaction to proceed at a lower temperature than would be possible in the absence of such conversion catalyst.

[0180] In some non-limiting embodiments, the liquid composition is converted to a polyimide film by a modified thermal conversion process. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further comprises a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further comprises a conversion catalyst selected from the group consisting of tertiary amines. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further comprises a conversion catalyst selected from the group consisting of tributylamine, dimethylethanolamine, isoquinoline, 1,2-dimethylimidazole, N-methylimidazole, 2-methylimidazole, 2-ethyl-4-imidazole, 3,5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 5-methylbenzimidazole, and the like.

[0181] In some non-limiting embodiments of the modified thermal conversion process, the conversion catalyst is present at 5 weight percent or less, in some non-limiting embodiments 3 weight percent or less, in some non-limiting embodiments 1 weight percent or less, and in some non-limiting embodiments 1 weight percent of the polyamic acid solution.

[0182] In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains tributylamine as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains dimethylethanolamine as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains isoquinoline as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 1,2-dimethylimidazole as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 3,5-dimethylpyridine as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 5-methylbenzimidazole as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains N-methylimidazole as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 2-methylimidazole as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 2-ethyl-4-imidazole as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 3,4-dimethylpyridine as a conversion catalyst. In some non-limiting embodiments of the modified thermal conversion process, the liquid composition further contains 2,5-dimethylpyridine as a conversion catalyst.

[0183] In some non-limiting embodiments of the modified thermal conversion process, the liquid composition is coated onto a substrate such that the resulting film has a soft-baked thickness of less than 50 μm, in some non-limiting embodiments less than 40 μm, in some non-limiting embodiments less than 30 μm, in some non-limiting embodiments less than 20 μm, in some non-limiting embodiments 10 μm to 20 μm, in some non-limiting embodiments 15 μm to 20 μm, and in some non-limiting embodiments less than 10 μm.

[0184] In some non-limiting embodiments of the modified thermal conversion process, the coated substrate is soft-baked on a hotplate in proximity mode, where nitrogen gas is used to hold the coated substrate directly above the hotplate. In some non-limiting embodiments of the modified thermal conversion process, the coated substrate is soft-baked on a hotplate in full-contact mode, where the coated substrate is in direct contact with the hotplate surface. In some non-limiting embodiments of the modified thermal conversion process, the coated substrate is soft-baked on a hotplate using a combination of proximity mode and full-contact mode.

[0185] In some non-limiting embodiments of the modified thermal conversion process, the coated substrate is soft baked using a hot plate set at 80°C, in some non-limiting embodiments 90°C, in some non-limiting embodiments 100°C, in some non-limiting embodiments 110°C, in some non-limiting embodiments 120°C, in some non-limiting embodiments 130°C, and in some non-limiting embodiments 140°C.

[0186] In some non-limiting embodiments of the modified thermal conversion process, the coated substrate is soft baked for a total time of more than 10 minutes, in some non-limiting embodiments, less than 10 minutes, in some non-limiting embodiments, less than 8 minutes, in some non-limiting embodiments, less than 6 minutes, in some non-limiting embodiments, less than 4 minutes, in some non-limiting embodiments, less than 4 minutes, and in some non-limiting embodiments, less than 2 minutes.

[0187] In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at two preselected temperatures for two preselected time intervals, which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at three preselected temperatures for three preselected time intervals, which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at four preselected temperatures for four preselected time intervals, which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at five preselected temperatures for five preselected time intervals, which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at six preselected temperatures for six preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at seven preselected temperatures for seven preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at eight preselected temperatures for eight preselected time intervals, each of which can be the same or different. In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated base material is then cured at nine preselected temperatures for nine preselected time intervals, each of which can be the same or different.In some non-limiting embodiments of the modified thermal conversion process, the soft-baked coated substrate is then cured at 10 preselected temperatures for 10 preselected time intervals, each of which can be the same or different.

[0188] In some non-limiting embodiments of the modified thermal conversion process, the preselected temperature is greater than 80°C, in some non-limiting embodiments, 100°C, in some non-limiting embodiments, greater than 100°C, in some non-limiting embodiments, 150°C, in some non-limiting embodiments, greater than 150°C, in some non-limiting embodiments, 200°C, in some non-limiting embodiments, greater than 200°C, in some non-limiting embodiments, 220°C, in some non-limiting embodiments, greater than 220°C, in some non-limiting embodiments, 230°C, in some non-limiting embodiments, greater than 230°C, in some non-limiting embodiments, 240°C, in some non-limiting embodiments, greater than 240°C, in some non-limiting embodiments, 250°C, and ...40°C, in some non-limiting embodiments, 250°C, and in some non-limiting embodiments, greater than 220°C, in some non-limiting embodiments, 230°C, in some non-limiting embodiments, greater than 230°C, in some non-limiting embodiments, 240°C, in some non-limiting embodiments, greater than 240°C, in some non-limiting embodiments, 250°C, and in some non-limiting embodiments, greater than 220°C In some non-limiting embodiments, the temperature is greater than 250°C, and in some non-limiting embodiments, 260°C, and in some non-limiting embodiments, greater than 260°C, and in some non-limiting embodiments, 270°C, and in some non-limiting embodiments, greater than 270°C, and in some non-limiting embodiments, 280°C, and in some non-limiting embodiments, greater than 280°C, and in some non-limiting embodiments, 290°C, and in some non-limiting embodiments, greater than 290°C, and in some non-limiting embodiments, 300°C, and in some non-limiting embodiments, less than 300°C, and in some non-limiting embodiments, less than 290°C, and in some non-limiting embodiments, less than 280°C, and in some non-limiting embodiments, less than 270°C, and in some non-limiting embodiments, less than 260°C, and in some non-limiting embodiments, less than 250°C.

[0189] In some non-limiting embodiments of the modified thermal conversion process, one or more of the preselected time intervals is 2 minutes, in some non-limiting embodiments, 5 minutes, in some non-limiting embodiments, 10 minutes, in some non-limiting embodiments, 15 minutes, in some non-limiting embodiments, 20 minutes, in some non-limiting embodiments, 25 minutes, in some non-limiting embodiments, 30 minutes, in some non-limiting embodiments, 35 minutes, in some non-limiting embodiments, 40 minutes, in some non-limiting embodiments, 45 minutes, in some non-limiting embodiments, 50 minutes, in some non-limiting embodiments, 55 minutes, in some non-limiting embodiments, 60 minutes, in some non-limiting embodiments, greater than 60 minutes, in some non-limiting embodiments, between 2 minutes and 60 minutes, in some non-limiting embodiments, between 2 minutes and 90 minutes, and in some non-limiting embodiments, between 2 minutes and 120 minutes.

[0190] In some non-limiting embodiments of the modified thermal conversion process, a method for producing a polyimide film includes, in order, the following steps: coating a substrate with a liquid composition including a conversion chemical; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications, such as those disclosed herein.

[0191] In some non-limiting embodiments of the modified thermal conversion process, a method for producing a polyimide film comprises, in order, the following steps: coating a substrate with a liquid composition comprising a conversion chemical; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications, such as those disclosed herein.

[0192] In some non-limiting embodiments of the modified thermal conversion process, a method for producing a polyimide film consists essentially of the following steps, in order: coating a substrate with a liquid composition including a conversion chemical; soft-baking the coated substrate; and treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals, whereby the polyimide film exhibits satisfactory properties for use in electronic applications, such as those disclosed herein.

[0193] 5. Electronic Devices The polyimide films disclosed herein may be suitable for use in multiple layers in electronic display devices, such as OLED and LCD displays. Non-limiting examples of such layers include device substrates, touch panels, substrates for color filter sheets, cover films, etc. The specific material property requirements for each application are unique and can be addressed by appropriate composition and processing conditions for the polyimide films disclosed herein.

[0194] In some embodiments, a flexible alternative to glass in electronic devices is a polyimide film having repeating units of Formula II detailed above.

[0195] Organic electronic devices that may benefit from one or more layers containing at least one compound described herein include, but are not limited to, (1) devices that convert electrical energy into radiation (e.g., light-emitting diodes, light-emitting diode displays, lighting devices, luminaires, or diode lasers), (2) devices that detect signals through electronic processes (e.g., photodetectors, photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes, infrared detectors, and biosensors), (3) devices that convert radiation into electrical energy (e.g., photovoltaic devices or solar cells), (4) devices that convert light of one wavelength to light of a longer wavelength (e.g., downconverting phosphor devices), and (5) devices that include one or more electronic components containing one or more organic semiconductor layers (e.g., transistors or diodes). Other uses of the compositions according to the present invention include coating materials for memory storage devices, antistatic films, biosensors, electrochemical devices, energy storage devices such as solid electrolyte capacitors and rechargeable batteries, and electromagnetic shielding applications.

[0196] An example of a polyimide film that can serve as a flexible alternative to glass as described herein is shown in FIG. 1. The flexible film 100 can have the properties described in the embodiments of the present disclosure. In some embodiments, a polyimide film that can serve as a flexible alternative to glass is included in an electronic device. FIG. 2 illustrates an example where an electronic device 200 is an organic electronic device. The device 200 has a substrate 100, an anode layer 110 and a second electrical contact layer, a cathode layer 130, and a photoactive layer 120 therebetween. Optionally, additional layers may be present. The layer adjacent to the anode layer may be a hole injection layer (not shown), sometimes referred to as a buffer layer. The layer adjacent to the hole injection layer may be a hole transport layer (not shown) comprising a hole transport material. The layer adjacent to the cathode layer may be an electron transport layer (not shown) comprising an electron transport material. Optionally, the device may employ one or more additional hole-injection or hole-transport layers (not shown) next to the anode 110 and / or one or more additional electron-injection or electron-transport layers (not shown) next to the cathode 130. Layers 110-130 are individually and collectively referred to as organic active layers. Additional layers that may or may not be present include color filters, touch panels, and / or cover sheets. In addition to the substrate 100, one or more of these layers may also be fabricated from the polyimide films disclosed herein.

[0197] The different layers are discussed further herein with reference to Figure 2. However, the discussion applies to other configurations as well.

[0198] In some embodiments, the different layers have thicknesses in the following ranges: substrate 100, 5 to 100 microns; anode 110, 500 to 5,000 Å, and in some embodiments, 1,000 to 2,000 Å; hole injection layer (not shown), 50 to 2,000 Å, and in some embodiments, 200 to 1,000 Å; hole transport layer (not shown), 50 to 3,000 Å, and in some embodiments, 200 to 2,000 Å; photoactive layer 120, 10 to 2,000 Å, and in some embodiments, 100 to 1,000 Å; electron transport layer (not shown), 50 to 2,000 Å, and in some embodiments, 100 to 1,000 Å; and cathode 130, 200 to 10,000 Å, and in some embodiments, 300 to 5,000 Å. The desired ratio of layer thicknesses will depend on the exact nature of the materials used.

[0199] In some embodiments, organic electronic devices (OLEDs) contain flexible alternatives to glass as disclosed herein.

[0200] In some embodiments, an organic electronic device includes a substrate, an anode, a cathode, and a photoactive layer therebetween, and further includes one or more additional organic active layers. In some embodiments, the additional organic active layer is a hole transport layer. In some embodiments, the additional organic active layer is an electron transport layer. In some embodiments, the additional organic layer is both a hole transport layer and an electron transport layer.

[0201] The anode 110 is an electrode that is particularly efficient for injecting positive charge carriers. The anode can be fabricated from materials containing, for example, metals, mixed metals, alloys, metal oxides, or mixed-metal oxides, or it can be conductive polymers and mixtures thereof. Suitable metals include Group 11 metals, Groups 4, 5, and 6 metals, and Groups 8-10 transition metals. If the anode is optically transparent, mixed-metal oxides of Groups 12, 13, and 14 metals, such as indium tin oxide, are commonly used. The anode can also include organic materials such as polyaniline, as described in "Flexible light-emitting diodes made from soluble conducting polymers," Nature, Vol. 357, pp. 477-479 (June 11, 1992). At least one of the anode and cathode must be at least partially transparent so that the generated light can be observed.

[0202] An optional hole injection layer can include a hole injection material. The terms "hole injection layer" or "hole injection material" are intended to mean an electrically conductive or semiconducting material, which may have one or more functions in an organic electronic device, including, but not limited to, planarization of underlying layers, charge transport and / or charge injection properties, scavenging of impurities such as oxygen or metal ions, and other aspects to promote or improve the performance of an organic electronic device. The hole injection material can be a polymer, oligomer, or small molecule, and can be in the form of a solution, dispersion, suspension, emulsion, colloidal mixture, or other composition.

[0203] The hole injection layer is often formed of a polymeric material, such as polyaniline (PANI) or polyethylenedioxythiophene (PEDOT), doped with a protonic acid. The protonic acid may be, for example, poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), or the like. The hole injection layer 120 may include charge-transfer compounds, such as copper phthalocyanine and tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ). In some embodiments, the hole injection layer 120 is fabricated from a dispersion of a conductive polymer and a colloid-forming polymeric acid. Such materials are described, for example, in published U.S. Patent Applications 2004-0102577, 2004-0127637, and 2005-0205860.

[0204] Other layers may contain hole transport materials. Examples of hole transport materials for the hole transport layer are summarized in, for example, Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 18, pp. 837-860, 1996, by Y. Wang. Both hole transport small molecules and hole transport polymers can be used. Commonly used hole transport molecules include, but are not limited to, 4,4',4''-tris(N,N-diphenyl-amino)-triphenylamine (TDATA); 4,4',4''-tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine (MTDATA); N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD); 4,4'-bis(carbazol-9-yl)biphenyl (CBP); 1,3-bis(carbazol-9-yl)benzene (mCP); 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC); N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biphenyl]-4,4'-diamine (ETPD); tetrakis(3-methylphenyl)-N,N,N ',N'-2,5-Phenylenediamine (PDA); α-phenyl 4-N,N-diphenylaminostyrene (TPS); p(diethylamino)benzaldehyde diphenylhydrazone (DEH); triphenylamine (TPA); bis[4(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP); 1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino) phenyl]pyrazoline (PPR or DEASP); 1,2 trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB); N,N,N',N'-tetrakis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TTB); N,N'-bis(naphthalen-1-yl)-N,N'-bis-(phenyl)benzidine (α-NPB); and porphyrin compounds, such as copper phthalocyanine.Commonly used hole-transporting polymers include, but are not limited to, polyvinylcarbazole, (phenylmethyl)polysilane, poly(dioxythiophene), polyaniline, and polypyrrole. It is also possible to obtain hole-transporting polymers by doping hole-transporting molecules such as those described above into polymers such as polystyrene and polycarbonate. In some cases, triarylamine polymers, particularly triarylamine-fluorene copolymers, are used. In some cases, the polymers and copolymers are crosslinkable. Examples of crosslinkable hole-transporting polymers can be found, for example, in published U.S. Patent Application Publication No. 2005-0184287 and published PCT Application WO 2005 / 052027. In some embodiments, the hole-transporting layer is doped with a p-type dopant, such as tetrafluorotetracyanoquinodimethane and perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride.

[0205] Depending on the application of the device, photoactive layer 120 may be a light-emitting layer that is activated by an applied voltage (such as in a light-emitting diode or light-emitting electrochemical cell), a layer of material that absorbs light and emits light having a longer wavelength (such as in a down-converting phosphor device), or a layer of material that responds to radiant energy and generates a signal with or without an applied bias voltage (such as in a photodetector or photovoltaic device).

[0206] In some non-limiting embodiments, the photoactive layer includes a light-emitting compound as a photoactive material. In some non-limiting embodiments, the photoactive layer further includes a host material. Examples of host materials include, but are not limited to, chrysene, phenanthrene, triphenylene, phenanthroline, naphthalene, anthracene, quinoline, isoquinoline, quinoxaline, phenylpyridine, carbazole, indolocarbazole, furan, benzofuran, dibenzofuran, benzodifuran, and metal quinolinate complexes. In some non-limiting embodiments, the host material is deuterated.

[0207] In some non-limiting embodiments, the photoactive layer comprises (a) a dopant capable of electroluminescence having an emission maximum between 380 and 750 nm, (b) a first host compound, and (c) a second host compound. Suitable second host compounds are described above.

[0208] In some non-limiting embodiments, the photoactive layer includes only (a) a dopant capable of electroluminescence having an emission maximum between 380 and 750 nm, (b) a first host compound, and (c) a second host compound, in which case there are no additional materials present that would substantially alter the principle of operation or distinguishing properties of the layer.

[0209] In some non-limiting embodiments, the first host is present in a higher concentration, by weight, in the photoactive layer than the second host.

[0210] In some non-limiting embodiments, the weight ratio of the first host to the second host in the photoactive layer is in the range of 10:1 to 1:10, in some non-limiting embodiments, the weight ratio is in the range of 6:1 to 1:6, in some embodiments, in the range of 5:1 to 1:2, and in some embodiments, in the range of 3:1 to 1:1.

[0211] In some non-limiting embodiments, the weight ratio of dopant to total host is in the range of 1:99 to 20:80, and in some embodiments, in the range of 5:95 to 15:85.

[0212] In some non-limiting embodiments, the photoactive layer includes (a) a red-emitting dopant, (b) a first host compound, and (c) a second host compound.

[0213] In some non-limiting embodiments, the photoactive layer includes (a) a green-emitting dopant, (b) a first host compound, and (c) a second host compound.

[0214] In some non-limiting embodiments, the photoactive layer includes (a) a yellow-emitting dopant, (b) a first host compound, and (c) a second host compound.

[0215] The optional layer can function to facilitate electron transport and also serve as a confinement layer to prevent exciton quenching at layer interfaces, hi some non-limiting embodiments, this layer promotes electron mobility and reduces exciton quenching.

[0216] In some non-limiting embodiments, such layers include other electron-transporting materials. Examples of electron-transporting materials that can be used in the optional electron-transporting layer include metal chelated oxinoid compounds, including metal quinolate derivatives such as tris(8-hydroxyquinolato)aluminum (AlQ), bis(2-methyl-8-quinolinolato)(p-phenylphenolato)aluminum (BAlq), tetrakis-(8-hydroxyquinolato)hafnium (HfQ), and tetrakis-(8-hydroxyquinolato)zirconium (ZrQ); and 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD). Examples of suitable electron transport materials include azole compounds such as 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), and 1,3,5-tri(phenyl-2-benzimidazole)benzene (TPBI); quinoxaline derivatives such as 2,3-bis(4-fluorophenyl)quinoxaline; phenanthrolines such as 4,7-diphenyl-1,10-phenanthroline (DPA) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (DDPA); triazines; fullerenes; and mixtures thereof. In some embodiments, the electron transport material is selected from the group consisting of metal quinolates and phenanthroline derivatives. In some embodiments, the electron transport layer further comprises an n-type dopant. N-dopant materials are well known. n-Dopants include, but are not limited to, Group 1 and Group 2 metals; Group 1 and Group 2 metal salts, such as LiF, CsF, and Cs2CO3; Group 1 and Group 2 metal organic compounds, such as Li quinolate; and molecular n-dopants, such as leuco dyes, metal complexes, such as W2(hpp)4 (where hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido-[1,2-a]-pyrimidine) and cobaltocene, tetrathianaphthacene, bis(ethylenedithio)tetrathiafulvalene, heterocyclic radicals or diradicals, and dimers, oligomers, polymers, dispiro compounds, and polycycles of heterocyclic radicals or diradicals.

[0217] An optional electron injection layer may be deposited over the electron transport layer. Examples of electron injection materials include, but are not limited to, Li-containing organometallic compounds, LiF, Li2O, Li quinolate, Cs-containing organometallic compounds, CsF, Cs2O, and Cs2CO3. This layer may react with the underlying electron transport layer, the overlying cathode, or both. When an electron injection layer is present, the amount of material deposited is generally in the range of 1 to 100 Å, and in some embodiments, 1 to 10 Å.

[0218] The cathode 130 is an electrode that is particularly efficient for injecting electrons or negative charge carriers. The cathode can be any metal or nonmetal that has a lower work function than the anode. Materials for the cathode can be selected from the Group 1 alkali metals (e.g., Li, Cs), Group 2 (alkaline earth) metals, rare earth elements and lanthanides, and Group 12 metals, including the actinides. Materials such as aluminum, indium, calcium, barium, samarium, and magnesium, as well as combinations, can be used.

[0219] It is known to have other layers in organic electronic devices. For example, a layer (not shown) for controlling the amount of positive charge injected and / or for providing bandgap matching of the layers, or for functioning as a protective layer, may be present between the anode 110 and the hole injection layer (not shown). Layers known in the art, such as copper phthalocyanine, silicon oxynitride, fluorocarbons, silanes, or ultrathin layers of metals, such as Pt, can be used. Alternatively, some or all of the anode layer 110, active layer 120, or cathode layer 130 can be surface treated to increase charge carrier transport efficiency. The selection of materials for each of the constituent layers is preferably determined by balancing the positive and negative charges in the emitter layer to provide a device with high electroluminescence efficiency.

[0220] It is understood that each functional layer may be composed of two or more layers.

[0221] The device layers can generally be formed by any deposition technique or combination of techniques, including vapor deposition / PECVD, liquid deposition, and thermal transfer. Substrates such as glass, plastic, and metal can be used. Conventional deposition techniques can be used, such as thermal evaporation, chemical vapor deposition, etc.

[0222] As an alternative to vapor deposition techniques, the organic layers can be applied from solutions or dispersions in suitable solvents using conventional coating or printing techniques, including, but not limited to, coating, dip coating, roll-to-roll techniques, inkjet printing, continuous nozzle printing, screen printing, gravure printing, and the like.

[0223] For liquid deposition methods, the appropriate solvent for a particular compound or related class of compounds can be readily determined by one skilled in the art. For some applications, it is desirable for the compound to be dissolved in a non-aqueous solvent. Such non-aqueous solvents include those listed in C1-C6. 20 They can be relatively polar, such as alcohols, ethers, and acid esters, or C1-C 12 The solvent may be relatively non-polar, such as an alkane or an aromatic compound such as toluene, xylene, trifluorotoluene, etc. Other suitable liquids for use in producing a liquid composition containing the novel compound as any of the solutions or dispersions described herein include, but are not limited to, chlorinated hydrocarbons (e.g., methylene chloride, chloroform, chlorobenzene), aromatic hydrocarbons (e.g., substituted and unsubstituted toluene and xylene), trifluorotoluene, etc., polar solvents (e.g., tetrahydrofuran (THP), N-methylpyrrolidone), esters (e.g., ethyl acetate), alcohols (e.g., isopropanol), ketones (e.g., cyclopentatone), and mixtures thereof. Suitable solvents for electroluminescent materials are described, for example, in published PCT application WO 2007 / 145979.

[0224] In some non-limiting embodiments, the device is fabricated by liquid deposition of the hole injection layer, hole transport layer, and photoactive layer, and by vapor deposition of the anode, electron transport layer, electron injection layer, and cathode onto a flexible substrate.

[0225] It is understood that the efficiency of the device can be improved by optimizing other layers within the device. For example, more efficient cathodes such as Ca, Ba, or LiF can be used. Shaped substrates and novel hole transport materials that result in lower operating voltages or increase quantum efficiency can also be applied. Additional layers can also be added to adjust the energy levels of the various layers and promote electroluminescence.

[0226] In some non-limiting embodiments, the device has the following structure, in order: substrate, anode, hole injection layer, hole transport layer, photoactive layer, electron transport layer, electron injection layer, cathode.

[0227] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. Furthermore, the materials, methods, and examples are illustrative only and not intended to be limiting. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. [Example]

[0228] The concepts described herein are further illustrated in the following examples, which are not intended to limit the scope of the invention as claimed.

[0229] Example The concepts described herein are further illustrated in the following examples, which are not intended to limit the scope of the invention as claimed.

[0230] Typical synthesis of parent polyamic acid Preparation of a liquid composition based on PMDA / 6FDA / TFMB 80 / 20 / 100 in NMP. 40.0 g of TFMB (0.125 mol) and 220 mL of 1-methyl-2-pyrrolidone (NMP) were placed in a 1 L reaction flask equipped with a nitrogen inlet and outlet, a mechanical stirrer, and a thermocouple. The mixture was stirred at room temperature under a nitrogen atmosphere for approximately 30 minutes. Then, 11.098 g (0.025 mol) of 6FDA was slowly added in small portions to the stirred solution of diamine, followed by 21.251 g (0.0974 mol) of PMDA and 60 mL of NMP in small portions. The rate of dianhydride addition was controlled to keep the maximum reaction temperature below 30°C. After dianhydride addition was complete, an additional 90 mL of NMP was used to wash any remaining dianhydride powder from the vessel and reaction flask walls. The resulting mixture was stirred for 7 days. Solution viscosity was monitored by removing a small sample from the reaction flask for testing using a Brookfield cone and plate viscometry. Viscosity was adjusted by adding NMP and PMDA (0.001-0.0026 mol). The final viscosity of the polymer solution was 4577 cps at 25 °C.

[0231] Example 1 PMDA / 6FDA / / TFMB80 / 20 / / 100 containing 3 wt% trihexylphosphine (THP). The liquid composition PMDA / 6FDA / / TFMB80 / 20 / / 100 prepared above was mixed with 3 wt% trihexylphosphine in a Thinky mixer (500 rpm / 30 s, 101.3 kPa, 2000 rpm / 90 s, 30 kPa). A polyimide film (Film 1) was prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 min), and curing in an oven with an O2 level of ≤50 ppm in N2. The maximum curing temperature was 410°C.

[0232] Example 2 PMDA / 6FDA / / TFMB80 / 20 / / 100 containing 3 wt% trihexylphosphine (THP). The liquid composition PMDA / 6FDA / / TFMB80 / 20 / / 100 prepared above was mixed with 3 wt% trihexylphosphine in a Thinky mixer (500 rpm / 30 s, 101.3 kPa, 2000 rpm / 90 s, 30 kPa). A polyimide film (Film 2) was prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 min), and curing in an oven with an O2 level of ≤50 ppm in N2. The maximum curing temperature was 430°C.

[0233] Comparative Examples 1 and 2 Comparative polyimide films 1 and 2 were prepared from the PMDA / 6FDA / / TFMB80 / 20 / / 100 liquid compositions prepared as above and cured in Examples 1 and 2, respectively, without the addition of trihexylphosphine (THP).

[0234] Characterization of polyimide films A Hunter Lab spectrophotometer was used to measure b*, yellowness index, and % transmittance (%T) over the wavelength range of 360 nm to 780 nm. Thermal measurements of the films were performed using a combination of thermogravimetric and thermomechanical analysis appropriate for the specific parameters reported herein. Mechanical properties were measured using Instron equipment.

[0235] The properties of the polyimide films are reported in Table 1.

[0236] [Table 1]

[0237] In all cases, the film's T g is over 450°C, which is T g was the upper limit of the measuring instrument used to measure it.

[0238] Table 1 shows that polyimide films made from liquid compositions containing 3 wt. % trihexylphosphine (THP) exhibit improved transparency (lower b* / YI and higher average transmittance) compared to samples without the additive. The presence of the additive does not adversely affect other measured film properties.

[0239] Example 3 PMDA / BPDA / 6FDA / FSTD (fluoroalkyl-substituted terphenyldiamine) 50 / 45 / 5 / 100 containing 2 wt% bis(2,4,4-trimethylpentyl)phosphinic acid (BPA). FSTD and liquid compositions based thereon are described, for example, in published patent application WO 2020 / 219411. The liquid composition was prepared in a manner similar to that used to prepare the parent polyamic acid associated with Examples 1 and 2 above. A polyimide film (Film 3) was fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N oven with an O2 level of ≤50 ppm. The maximum cure temperature was 450°C.

[0240] Example 4 PMDA / BPDA / 6FDA / / FSTD / TFMB (fluoroalkyl-substituted terphenyldiamine) 50 / 45 / 5 / / 50 / 50 containing 2 wt% bis(2,4,4-trimethylpentyl)phosphinic acid (BPA). FSTD and liquid compositions based thereon are described, for example, in published patent application WO 2020 / 219411. The liquid composition was prepared in a manner similar to that used to prepare the parent polyamic acid associated with Examples 1 and 2 above. A polyimide film (Film 4) was fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven with an O2 level of ≤50 ppm. The maximum cure temperature was 450°C.

[0241] Comparative Examples 3 and 4 Comparative Polyimide Films 3 and 4 were prepared from the liquid compositions prepared as described above and cured in Examples 3 and 4, respectively, without the addition of bis(2,4,4-trimethylpentyl)phosphine (BPA).

[0242] The properties of the polyimide films were measured as described above and are reported in Table 2.

[0243] [Table 2]

[0244] Table 2 shows that the samples containing bis(2,4,4-trimethylpentyl)phosphinic acid additive exhibit improved transparency (lower b* / YI and higher transmittance) compared to the samples without additive. A decrease in CTE is also observed with the addition of bis(2,4,4-trimethylpentyl)phosphinic acid.

[0245] Examples 5 to 10 BPDA / 6FDA / / FSTD (fluoroalkyl-substituted terphenyl diamine) 98 / 2 / / 100 containing various amounts of trihexylphosphine oxide (THPO), di-n-hexylphosphinic acid (DHPA), and hexyl dihexylphosphinate (HDHP) as shown in Table 3. FSTD and liquid compositions based thereon are described, for example, in published patent application WO 2020 / 219411. The liquid compositions were prepared in a manner similar to that used to prepare the parent polyamic acids associated with Examples 1 and 2 above. Polyimide films (Films 5–10) were fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N oven with O levels ≤50 ppm. The maximum cure temperature was 450°C. Comparative Film 5 was fabricated from a liquid composition containing a non-phosphorus-containing additive.

[0246] The properties of the polyimide films were measured as described above and are reported in Table 3.

[0247] [Table 3]

[0248] Table 3 shows that the samples containing the phosphorus-containing additive and the additive mixture exhibit improved transparency (lower b* / YI and higher transmittance) compared to the samples without the additive.

[0249] Example 11 PMDA / BPDA / 6FDA / TFMB 40 / 40 / 20 / 100 containing 2 wt% bis(2,4,4-trimethylpentyl)phosphinic acid (BPA). A 1-L reaction flask equipped with a nitrogen inlet and outlet, a mechanical stirrer, and a thermocouple was charged with 30.0 g of TFMB (0.0937 mol) and 142 mL of 1-methyl-2-pyrrolidinone (NMP). The mixture was stirred at room temperature (25 °C) under nitrogen for approximately 20 minutes to obtain a colorless solution. Then, 8.323 g (0.0187 mol) of 6FDA was slowly added in small portions to the stirred solution of diamine with 50 mL of NMP, followed by the addition of 11.025 g (0.0375 mol) of sBPDA and 50 mL of NMP in small portions. Finally, 7.765 g (0.0356 mol) of PMDA was slowly added in small portions to the stirred solution. The rate of dianhydride addition was controlled to keep the maximum reaction temperature below 28 °C. After dianhydride addition was complete, an additional 50 mL of NMP was used to wash any remaining dianhydride powder from the vessel and reaction flask walls, and the resulting mixture was stirred for 7 days. Using a Brookfield cone and plate viscometry, the solution viscosity was monitored by removing a small sample from the reaction flask for testing. The viscosity was adjusted by adding NMP and PMDA (0.001 to 0.0017 mol). The final viscosity of the polymer solution was 4874 cps at 25 °C.

[0250] Example 11 contained 2 wt. % bis(2,4,4-trimethylpentyl)phosphinic acid, which was added to the above composition and mixed using a Thinky mixer (500 rpm / 30 s, 101.3 kPa, 2000 rpm / 90 s, 30 kPa). A polyimide film (Film 11) was prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 min), and curing in a N2 oven with an O2 level of ≤ 50 ppm. The maximum cure temperature was 450°C.

[0251] Comparative Example 11 was prepared similarly without the addition of bis(2,4,4-trimethylpentyl)phosphinic acid to produce Comparative Film 11.

[0252] The films were characterized as described above and the results are shown in Table 4.

[0253] [Table 4]

[0254] Table 4 shows that the samples containing bis(2,4,4-trimethylpentyl)phosphinic acid additive exhibit improved transparency (lower b* / YI and higher transmittance) compared to the samples without additive. A decrease in CTE is also observed with the addition of bis(2,4,4-trimethylpentyl)phosphinic acid.

[0255] Examples 12-13 Brown polyamic acid compositions BPDA / / PPD(100 / / 100) (Example 12) and PMDA / BPDA / / PPD(60 / 40 / / 100) (Example 13) were prepared as disclosed, for example, in U.S. Patent Application Publication No. 2008-0044639. Example 12 contained 3 wt.% triphenylphosphine (TPP) in BPDA / / PPD(100 / / 100), and Example 13 contained 3 wt.% triphenylphosphine (TPP) in PMDA / BPDA / / PPD(60 / 40 / / 100). The TPP in these compositions was added and mixed using a Thinky mixer (500 rpm / 30 s, 101.3 kPa, 2000 rpm / 90 s, 30 kPa). Polyimide films were prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven with an O2 level of ≤ 50 ppm. The maximum cure temperature in each case was 475°C. Corresponding comparative examples were prepared without the addition of TPP.

[0256] The films were characterized as described above and the results are shown in Table 5.

[0257] [Table 5]

[0258] Table 5 shows that the improvements in thermal and optical properties realized by the addition of TPP additives to compositions for brown polyimide films may be less than those realized in compositions resulting in clear polyimide films, if any improvements are realized at all.

[0259] Examples 14 to 51 The polyamic acid liquid composition of Example 3 was prepared as described above by replacing bis(2,4,4-trimethylpentyl)phosphinic acid with the phosphorus-containing additives shown in Table 6. All phosphorus-containing additives were used at 3 wt%. Polyimide films were fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven with an O2 level of ≤ 50 ppm. The maximum cure temperature was 430°C.

[0260] Table 6 reports the additives used in each example, the percent change in coefficient of thermal expansion (CTE) relative to the parent polyimide, and the percent change in yellowness index (YI) relative to the parent polyimide.

[0261] [Table 6]

[0262] [Table 7]

[0263] Table 6 shows that the use of 3 wt. % of the phosphorus-containing additives listed therein can produce polyimide films with excellent thermal properties (lower CTE), excellent optical properties (lower YI), or both.

[0264] Examples 52 to 58 The polyamic acid liquid compositions reported in Table 7 were prepared as in the above examples, with the addition of 3 wt. % (di-tert-butylphosphino)biphenyl additive in all cases. Polyimide films were prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven with an O2 level of ≤ 50 ppm using the conditions reported in Table 6.

[0265] Table 7 reports the composition used for each example, the cure temperature and cure time, the percent change in coefficient of thermal expansion (CTE) relative to the parent polyimide, and the percent change in yellowness index (YI) relative to the parent polyimide.

[0266] [Table 8]

[0267] Table 7 shows that the use of 3 wt% (di-tert-butylphosphino)biphenyl additive can produce a variety of polyimide films with superior thermal properties (lower CTE), superior optical properties (lower YI), or both.

[0268] Example 59 BPDA / PMDA / ODPA / 6FDA / / FSTD / CHDA45 / 50 / 10 / 5 / / 95 / 5 containing 3 wt. % trihexylphosphine was prepared in a manner similar to that described hereinabove. Polyimide films were fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven at 430°C for 5 minutes with an O2 level of ≤50 ppm. Films fabricated from liquid compositions containing the phosphorus-containing additive are observed to exhibit a 24% reduction in CTE and a 15% reduction in yellowness index compared to similar films fabricated without trihexylphosphine.

[0269] Example 60 BPDA / PMDA / 6FDA / / FSTD / CHDA40 / 55 / 5 / / 95 / 5 containing 3 wt. % trihexylphosphine was prepared in a manner similar to that described hereinabove. Polyimide films were fabricated by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes) and curing in a N2 oven at 430°C for 5 minutes with an O2 level of ≤50 ppm. Films fabricated from the liquid composition containing the phosphorus-containing additive are observed to exhibit a 27% reduction in CTE and a 9% reduction in Yellowness Index compared to similar films fabricated without trihexylphosphine.

[0270] Example 61 and Example 62 In the above examples, the dianhydride and diamine were introduced into the reaction vessel and allowed to react before the phosphorus-containing additive was introduced into the liquid composition. This example demonstrates that the phosphorus-containing additive can be added to the reaction solvent before the dianhydride and diamine are added, and still realize the benefits of polyimide film properties (thermal, light, etc.).

[0271] The polyimide was based on a polyamic acid solution with the composition PMDA / BPDA / 6FDA / / FSTD50 / 45 / 5 / / 100 in NMP. The additive was 0.2% trihexylphosphine, and the composition was prepared as follows: In a glovebox, 400 g of 1-methyl-2-pyrrolidinone (NMP) and 0.80 g of trihexylphosphine (THP) were placed in a 500 mL bottle, and the resulting 0.2% solution was stirred at room temperature for 72 hours. This solution was used in the subsequent polymerization.

[0272] A 500 mL reactor equipped with nitrogen inlets and outlets, a mechanical stirrer, and a thermocouple was charged with 160 g of a 0.2% THP / NMP solution under a nitrogen atmosphere, followed by 33.62 g of FSTD. The mixture was stirred at room temperature for approximately 15 minutes. Then, 8.36 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was slowly added to the reaction, followed by 1.40 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). After stirring for 10 minutes, 6.61 g of pyromellitic dianhydride (PMDA) was added in small increments, maintaining the reaction temperature below 30 °C. An additional 40.0 g of THP solution was then used to wash down any residual monomer powder from the vessel and reaction flask walls. After stirring for 24 hours at room temperature, additional PMDA (0.206 g) was added to increase the molecular weight of the polymer. Solution viscosity was monitored using a Brookfield cone and plate viscometry by removing small samples from the reaction flask at regular intervals for testing. The mixture was stirred for an additional 80 hours at room temperature to allow the polymer to equilibrate. During this time, the polymer solution was diluted twice with 0.2% THP / NMP solution (a total of 80.5 g added) to reduce the polymer viscosity. The final viscosity of the polymer solution was 11,730 cp at 25°C.

[0273] Table 8 shows a comparison of PI films (cured at 430°C) of samples treated with trihexylphosphine at the beginning of polymerization (pre-treatment) and at the end of polymerization (post-treatment).

[0274] [Table 9]

[0275] Table 8 shows that the addition of phosphorus-containing additives can improve thermal and optical properties, whether the additive is introduced before or after the polymerization of the polyamic acid.

[0276] Examples 63 to 72 The polyamic acid liquid compositions of Examples 3 and 14-51 were prepared as described above, except that (di-tert-butylphosphino)biphenyl was used as the phosphorus-containing additive. The additive loading for each example is reported in Table 9. Polyimide films were prepared by spin coating, followed by soft baking on a hotplate (100°C for 4 minutes), and curing in a N2 oven with an O2 level of ≤50 ppm for the times and temperatures reported in Table 9.

[0277] Table 9 also reports the % change in coefficient of thermal expansion (CTE) relative to the parent polyimide from 100°C to 350°C, and the % change in yellowness index (YI) relative to the parent polyimide.

[0278] [Table 10]

[0279] Examples 73 to 75 The polyamic acid liquid compositions of Examples 63-72 were prepared as described above, except that trihexylphosphine was used as the phosphorus-containing additive. The additive loading for each example is reported in Table 10. Polyimide films were prepared by spin coating, followed by soft baking on a hot plate (100°C for 4 minutes), and curing in a N2 oven with an O2 level of ≤50 ppm for the times and temperatures reported in Table 10.

[0280] Table 10 also reports the percent change in coefficient of thermal expansion (CTE) relative to the parent polyimide from 100°C to 350°C, and the percent change in yellowness index (YI) relative to the parent polyimide.

[0281] [Table 11]

[0282] Examples 76 to 78 The polyamic acid liquid composition of Example 4 was prepared as described above, except that trihexylphosphine was used as the phosphorus-containing additive. The additive loading for each example is reported in Table 11. Polyimide films were prepared by spin coating, followed by soft baking on a hot plate (100°C for 4 minutes), and curing in a N2 oven with an O2 level of ≤ 50 ppm for the time and temperature reported in Table 11.

[0283] Table 11 also reports the % change in coefficient of thermal expansion (CTE) relative to the parent polyimide from 100°C to 350°C, and the % change in yellowness index (YI) relative to the parent polyimide.

[0284] [Table 12]

[0285] Tables 6-11 show that the thermal and optical properties of the polyimide films disclosed herein can be adjusted by considering the composition of the polyamic acid solution, the selection and amount of phosphorus-containing additive, and the curing conditions.

[0286] It should be noted that not all of the acts described above in the summary or examples are required, that some of the particular acts may not be required, and that one or more additional acts may be performed in addition to those described. Furthermore, the order in which the acts are listed is not necessarily the order in which the acts are performed.

[0287] In the foregoing specification, the concepts have been described with reference to specific embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the invention as set forth in the following claims. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention.

[0288] Benefits, other advantages, and solutions to problems have been described above with respect to particular embodiments. However, the benefits, advantages, solutions to problems, and any features that may give rise to or make more pronounced any benefit, advantage, or solution should not be construed as critical, required, or essential features of any or all claims.

[0289] It should also be appreciated that, for clarity, certain features are described herein in the context of separate embodiments, but may also be provided in combination in a single embodiment. Conversely, for brevity, various features described in the context of a single embodiment may also be provided individually or in any subcombination. The use of various ranges of numerical values ​​specified herein is described as approximations, as if the minimum and maximum values ​​within the stated ranges were both preceded by the word "about." In this format, slight variations above and below the stated ranges can be used to achieve substantially the same results as values ​​within the range. Furthermore, the disclosure of these ranges is intended to be a continuous range, including every value between the minimum and maximum average values, including fractional values ​​that may occur when some components of one value are mixed with components of a different value. Furthermore, when broader and narrower ranges are disclosed, it is within the contemplation of the invention to combine the minimum value from one range with the maximum value from another range, and vice versa.

Claims

1. Formula II 【Chemical 1】 (In the formula, R ａ are the same or different in each occurrence and represent one or more tetracarboxylic acid moiety residues; R ｂ are the same or different in each occurrence and represent one or more diamine residues. A polyimide film comprising the repeating unit structure Furthermore, The polyimide film is subjected to the following steps: coating a polyamic acid solution containing one or more tetracarboxylic acid components, one or more diamine components, and one or more phosphorus-containing additives in a high-boiling aprotic solvent onto a substrate; soft-baking the coated substrate; treating the soft-baked coated substrate at a plurality of preselected temperatures for a plurality of preselected time intervals; in that order, without repetition,

2. 10. The polyimide film of claim 1, wherein the polyamic acid solution comprising one or more tetracarboxylic acid components, one or more diamine components, and one or more phosphorus-containing additives in a high-boiling aprotic solvent is prepared according to a method of first adding the phosphorus-containing additive to the high-boiling aprotic solvent, stirring the resulting solution for a preselected time, and then adding the one or more tetracarboxylic acid components and the one or more diamine components.

3. 2. The polyimide film of claim 1, wherein the polyamic acid solution comprising one or more tetracarboxylic acid components, one or more diamine components, and one or more phosphorus-containing additives in a high-boiling aprotic solvent is prepared according to a method of first adding the one or more tetracarboxylic acid components and the one or more diamine components to the high-boiling aprotic solvent to form the polyamic acid solution, and then introducing the one or more phosphorus-containing additives into the polyamic acid solution.

4. 2. The polyimide film according to claim 1, wherein the maximum preselected temperature is 400°C or higher.

5. The polyimide film of claim 4 , wherein the method is carried out in an inert atmosphere.

6. 6. The polyimide film of claim 5, wherein the film has a CTE less than 10 ppm / °C, a b* less than 5, a yellowness index less than 8, and an average transmittance greater than 85% from 380 nm to 780 nm.

7. 10. An electronic device, wherein the polyimide film having the repeating unit of formula II according to claim 1 is used for a device component selected from the group consisting of a device substrate, a substrate for a color filter sheet, a cover film, and a touch screen panel.

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