Polyimide precursor, polyimide, method for producing the same, and use thereof

Abstract

The present application provides a kind of polyimide precursor, polyimide, its preparation method and application.The polyimide precursor has the repeat unit structure shown in formula I, the polyimide has the repeat unit structure shown in formula II:Wherein, R a It represents the residue of tetracarboxylic dianhydride component, and the residue of tetracarboxylic dianhydride component includes the residue of 9,9-bis(3,4-dicarboxyphenyl) fluorene dianhydride component;R b It represents the residue of aromatic diamine. The polyimide formed by the polyimide precursor, or the polyimide having the repeat unit shown in formula II has good solubility in various solvents, thereby giving it good processability; and the polyimide film provided by the present application has higher light transmittance, lower yellowness index, excellent thermal stability, higher glass transition temperature and good mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, and more specifically to a polyimide precursor, a polyimide and a method for preparing the same, a composition for forming a polyimide film, a polyimide film, a transparent structure, and an apparatus containing the transparent structure. Background Technology

[0002] The application of materials in the electronics field has relatively stringent requirements, including their structural, optical, thermal, electronic, and other properties. With the rapid development of the commercial electronics market, even more demanding requirements are being placed on the materials used. Polyimide is a typical polymer material in various electronic applications. The flexibility of polyimide allows it to replace glass in traditional electronic display devices, enabling the fabrication of flexible electronic devices.

[0003] For polyimide-based materials to be used in displays, the main physical properties required are optical and mechanical properties. Methods to prepare polyimides with excellent optical and mechanical properties have been reported, such as introducing various aliphatic groups and bulky groups into polyimides to improve their transparency; however, this results in a sacrifice of mechanical properties. Therefore, a multi-faceted strategy is needed to adjust the properties of transparent polyimides. Furthermore, the application of transparent polyimides involves diverse processing procedures, thus placing certain demands on the processability of high-performance transparent polyimides. Traditional rigid polyimides possess advantages such as extremely high heat resistance and high glass transition temperature; achieving high transparency and processability based on these advantages is a breakthrough that needs to be achieved.

[0004] Therefore, there is a need to develop a technology for polyimide that produces polyimide with good optical properties without compromising its excellent mechanical and physical properties; and it is hoped that the solubility of polyimide in common organic solvents can be improved, thereby making it processable in a variety of processes and thus applicable to various display materials, including materials that replace modified glass. Summary of the Invention

[0005] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions:

[0006] One objective of this invention is to provide a polyimide precursor having a repeating unit structure as shown in Formula I.

[0007]

[0008] Among them, R aRepresents a tetracarboxylic dianhydride component residue, and said tetracarboxylic dianhydride component residue includes 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residue; R b It represents an aromatic diamine residue.

[0009] That is, R in at least one repeating unit structure of the polyimide precursor a It consists of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianone component residues.

[0010] In some embodiments, the content of the 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residues in the polyimide precursor is 5-100 mol% of the total content of the tetracarboxylic acid dianhydride component residues. When the content of the 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residues is within the specified range, the polyimide and polyimide film formed based on the polyimide precursor have superior performance.

[0011] In some embodiments, the tetracarboxylic dianhydride component residues also include aromatic dianhydride component residues and / or alicyclic dianhydride component residues that are different from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

[0012] In some embodiments, R is formed b Aromatic diamine monomers include diamine compounds represented by formula III and / or formula IV:

[0013]

[0014] R1, R2, and R3 are independently selected from hydrogen, hydroxyl, cyano, halogen, alkyl, heteroalkyl, alkoxy, heteroalkoxy, haloalkyl, haloalkoxy, silyl, silanoxy, hydrocarbon aryl, substituted hydrocarbon aryl, heteroaryl, or substituted heteroaryl.

[0015] In some embodiments, the sources of the aromatic dianhydride component residues, which are different from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, include 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4-BPDA), 2,3,3′,4′-biphenyltetracarboxylic dianhydride (3,4-BPDA), 2,2′,3,3′-biphenyltetracarboxylic dianhydride (3,3-BPDA), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 3,4′-oxobisphthalic anhydride (3,4-ODPA), 4,4′-oxodiphthalic anhydride (4,4-ODPA), and 4,4′-sulfonyldiphthalic anhydride. One or more of the following: (SDPA), (isopropylidene diphenoxy)bis(phthalic anhydride) (BPADA), pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), bis(carboxyphenyl)dimethylsilane dianhydride (SIDA), 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride (DSDA), N-[4-[4-[(1,3-dioxo-2-benzofuran-5-carbonyl)amino]-2-(trifluoromethyl)phenyl]-3-(trifluoromethyl)phenyl]-1,3-dioxo-2-benzofuran-5-carboxamide (TA-TFMB) and / or their derivatives;

[0016] In some embodiments, the alicyclic dianhydride component residues are derived from one or more of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (HPMDA), 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride (DMCBDA), norcamphene-2-spiro-α-cyclopentanone-α′-spiro-2"-norcamphene-5,5″,6,6″-tetracarboxylic dianhydride (CpODA) and / or derivatives thereof.

[0017] In some embodiments, the diamine compound represented by Formula III and / or Formula IV is 5-100 mol of the aromatic diamine monomer.

[0018] In some embodiments, the diamine compound represented by Formula III includes one or more of the following compounds:

[0019]

[0020] In some embodiments, the diamine compound of formula IV includes one or more of the following compounds:

[0021]

[0022] In some embodiments, R is formed b Aromatic diamine monomers include diamine compounds represented by formula III-1.

[0023]

[0024] In some embodiments, R is formed b Aromatic diamine monomers include diamine compounds represented by formula IV-1.

[0025]

[0026] A second objective of this invention is to provide a polyimide having a repeating unit structure as shown in Formula II:

[0027]

[0028] Wherein, Ra represents a tetracarboxylic acid dianhydride component residue, and the tetracarboxylic acid component residue includes 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residue; R b It represents an aromatic diamine residue.

[0029] That is, R in at least one repeating unit structure of the polyimide a It consists of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianone component residues.

[0030] In some embodiments, the content of the 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residues in the polyimide is 5-100 mol% of the total content of the tetracarboxylic acid dianhydride component residues. When the content of the 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residues is within the above range, the polyimide has good solubility in some solvents, thereby giving it good processability.

[0031] In some embodiments, the polyimide has a solubility of 2 wt% or more, for example 3 wt% or more, for example 2 to 40 wt% in the following solvents: the solvents include one or more combinations of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), m-cresol, 1,4-dioxane, γ-butyrolactone and / or derivatives thereof.

[0032] In some embodiments, the glass transition temperature T of the polyimide is... g Greater than 300℃.

[0033] In some embodiments, the yellowness index (YI) of the polyimide is less than 15.0.

[0034] Further embodiments of the polyimide, such as the content of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residues, the specific selection of aromatic dianhydride component residues and / or alicyclic dianhydride component residues, and the formation of R... b Further technical solutions, such as the content and specific selection of aromatic diamine monomers, diamine compounds represented by Formula III and / or Formula IV, have been specifically described in the above-mentioned "A Polyimide Precursor" and will not be repeated here.

[0035] A third objective of this invention is to provide a method for preparing the polyimide precursor described in any of the above technical solutions, comprising: providing a first mixed reaction system containing tetracarboxylic dianhydride, an aromatic diamine, and a solvent, wherein the tetracarboxylic dianhydride includes 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride; and subjecting the first mixed reaction system to a polymerization reaction at a temperature of -10 to 80°C to obtain the polyimide precursor.

[0036] In some embodiments, the molar ratio of the tetracarboxylic dianhydride to the aromatic diamine is 0.98–1.02:0.98–1.02.

[0037] The fourth objective of this invention is to provide a method for preparing polyimide according to any of the above technical solutions, wherein the preparation method includes a chemical method and a solvothermal method;

[0038] The chemical method includes: imidizing the polyimide precursor described in any of the above technical solutions to obtain the polyimide;

[0039] The solvothermal method includes: providing a second mixed reaction system containing tetracarboxylic dianhydride, an aromatic diamine, and a solvent, wherein the tetracarboxylic dianhydride includes 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride; and subjecting the second mixed reaction system to a polymerization reaction at a temperature of 150–200°C to obtain the polyimide.

[0040] In some embodiments, the molar ratio of the tetracarboxylic dianhydride to the aromatic diamine is 0.98–1.02:0.98–1.02.

[0041] The fifth objective of this invention is to provide a liquid composition comprising:

[0042] The polyimide precursor and / or polyimide described in any of the above technical solutions;

[0043] At least one aprotic solvent.

[0044] In some embodiments, the aprotic solvent includes one or more combinations of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, m-cresol, 1,4-dioxane, γ-butyrolactone and / or derivatives thereof.

[0045] In some embodiments, the aprotic solvent is a high-boiling-point solvent with a boiling point above 100°C.

[0046] The sixth objective of this invention is to provide a polyimide film comprising the polyimide described in any of the above-mentioned technical solutions, or the polyimide film being obtained by curing the liquid composition.

[0047] In some embodiments, the 10 μm thick polyimide film has a glass transition temperature greater than 300°C and a yellowness index less than 15.0.

[0048] In some embodiments, the polyimide film has a total transmittance of over 80.0% in the wavelength range of 360-780 nm.

[0049] In some embodiments, the haze of the polyimide film is below 2.0%.

[0050] In some embodiments, the modulus of the polyimide film is 4.0 GPa or higher.

[0051] The polyimide film provided by this invention has a flexible feature, and therefore can be used as a substitute for glass, for example, as a substitute for glass in electronic devices.

[0052] The seventh objective of this invention is to provide a transparent structure, which includes the polyimide film described in any of the above technical solutions.

[0053] An eighth object of the present invention is to provide an apparatus having a transparent component, the apparatus comprising the transparent structure described in any of the foregoing technical solutions.

[0054] In some embodiments, the transparent structure can be used in components such as the device substrate, the substrate of the color filter, the cover film, the cover layer, the active display, the TFT layer, and / or the touch screen panel.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects:

[0056] (1) The polyimide precursor and polyimide structure provided by the present invention contain 9,9-bis(3,4-dicarboxyphenyl)fluorenidine (BPAF) component residues, which can improve the solubility of polyimide and make it have high solubility in a variety of solvents, thereby giving the polyimide good processability.

[0057] (2) The polyimide film provided by the present invention has high light transmittance, low yellowness index, excellent thermal stability, high glass transition temperature and good mechanical properties. The polyimide structure contains bulky 9,9-bis(3,4-dicarboxyphenyl)fluorene dihydric anhydride (BPAF) component residues and a large number of trifluoromethyl (-CF3) side groups. The bulky groups weaken the formation of electron transfer complexes and improve its optical properties.

[0058] (3) The polyimide film provided by the present invention contains a terphenyl structure, which can improve the brittleness problem of polyimide synthesized from 9,9-bis(3,4-dicarboxyphenyl)fluorenidine anhydride (BPAF), and endow the polyimide structure in the present invention with good flexibility characteristics, and thus can be used as a flexible substitute for glass in various equipment devices.

[0059] (4) Furthermore, the present invention has found that when the polyimide further has alicyclic dianhydride component residues, the alicyclic dianhydride forms a non-conjugated structure in the polymer chain, which can effectively reduce the formation of charge transfer complexes and further improve optical and physical properties, but will sacrifice some heat resistance properties. Attached Figure Description

[0060] Figure 1 This is the DMA test curve of the polyimide film of Example 83 of the present invention;

[0061] Figure 2 This is the TMA test curve of the polyimide film of Example 83 of the present invention.

[0062] Those skilled in the art will understand that the objects in the figures are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some objects in the figures may be enlarged relative to others to aid in understanding the embodiments. Detailed Implementation

[0063] The embodiments described in this specification can be modified in various other forms. The embodiments described in this specification are exemplary and not limiting. After reading this specification, those skilled in the art will understand that other aspects and embodiments are possible without departing from the scope of the invention.

[0064] 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 pertains. While similar or equivalent methods and materials described herein may be used in the practice or testing of embodiments of the invention, suitable methods and materials are described below. Unless a specific paragraph is quoted, all publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety, and in case of conflict, this specification, including definitions, shall prevail. Furthermore, materials, methods, and examples are illustrative only and are not intended to be limiting.

[0065] Beyond the scope described herein, many details regarding specific materials, processing behaviors, and circuits are conventional and can be found in books, articles, and other sources in the fields of organic light-emitting diode displays, photodetectors, photovoltaics, and semiconductor components.

[0066] The composition according to a specific embodiment is described below.

[0067] According to one specific embodiment, the polyimide precursor and the polyimide comprise units derived from aromatic diamines and units derived from tetracarboxylic dianhydrides.

[0068] The tetracarboxylic dianhydride comprises 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), and the aromatic diamine may comprise compounds represented by Formula III-1.

[0069]

[0070] By combining the use of compound III-1 as an aromatic diamine with 9,9-bis(3,4-dicarboxyphenyl)fluorenic anhydride (BPAF), a polyimide with good solubility in a solvent can be provided, thereby giving the polyimide good processability; and the polyimide has excellent mechanical and physical properties and optical and physical properties.

[0071] Although not bound by any specific theory, both the compound of formula III-1 and BPAF contain aromatic rings, which can increase the carbon content of the polyimide resin, thus providing a film with superior mechanical and physical properties while also possessing adequate optical and physical properties.

[0072] The aromatic diamine can be used alone as a compound of formula III-1, or it can be mixed with other aromatic diamines commonly used in the art as needed. For example, in addition to a compound of formula III-1, a second aromatic diamine different from that of formula III-1 may also be included.

[0073] The second aromatic diamine may, for example, contain substituted or unsubstituted C.6-30 Aromatic rings, wherein the aromatic ring can be a monocyclic ring; or a fused ring of two or more aromatic rings; or two or more aromatic rings connected by a single bond, C-bond, or C-bond. 1-5 The aromatic diamine may contain a non-fused ring linked by an alkylene group, an O group, or a C=O group. Alternatively, a fluorine substituent may be introduced into the second aromatic diamine, and the use of an aromatic diamine with a fluorine substituent can help improve the optical properties of a polyimide film prepared from the composition of one specific embodiment. Further, the second aromatic diamine may comprise an aromatic ring substituted with one or more trifluoroalkyl groups, which may be further substituted with other substituents besides the trifluoroalkyl group or remain unsubstituted.

[0074] The second aromatic diamine is selected, for example, from 2,2'-bis(trifluoromethyl)benzidine (TFMB), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (4BDAF), 2,2-bis(4-aminophenyl)hexafluoropropane (FA), 3,4′-diaminodiphenyl ether (ODA), 4,4′-diaminodiphenylmethane (pMDA), m-diphenylaminomethane (mMDA), 1,3-bis(3-aminophenoxy)benzene (133APB), 1,3-bis(4-aminophenyl)benzene The aromatic diamine may be one or more of the following: 1,4-bis(4-aminophenoxy)benzene (134APB), 1,4-bis(4-aminophenoxy)benzene (144APB), bis(4-aminophenyl)sulfone (4DDS), bis(3-aminophenyl)sulfone (3DDS), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (6HMDA), 2,6-diaminotoluene (2,6-DMT), 3,5-diaminotoluene (3,5-DMT), and their derivatives, or mixtures thereof, and is not necessarily limited thereto. More specifically, the second aromatic diamine may comprise 2,2'-bis(trifluoromethyl)benzidine (TFMB).

[0075] The aromatic diamine can be used alone as a compound of formula III-1, or it can be used in combination with a compound of formula III-1 and a second aromatic diamine. When a compound of formula III-1 and a second aromatic diamine are used in combination, although their mixing ratio is not limited, the content of compound III-1 can be, for example, more than 1 mol%, more than 2 mol%, more than 5 mol%, more than 10 mol%, more than 20 mol%, more than 30 mol%, more than 40 mol%, more than 50 mol%, more than 55 mol%, more than 60 mol%, or more than 70 mol%, and for example, less than 99 mol%, less than 98 mol%, less than 95 mol%, less than 90 mol%, less than 80 mol%, less than 75 mol%, less than 70 mol%, less than 65 mol%, less than 60 mol%, or less than 50 mol%, but is not necessarily limited to these.

[0076] The aromatic dianhydride can be used alone with the BPAF, or it can be mixed with other dianhydrides commonly used in the art as needed. For example, other dianhydrides can be selected from aromatic dianhydrides other than BPAF, wherein the aromatic dianhydride refers to a dianhydride containing at least one aromatic ring, which can be a monocyclic ring, a fused ring of two or more aromatic rings, or a non-fused ring of two or more aromatic rings connected by a single bond, a substituted or unsubstituted C1-5 alkylene group, O, or C=O.

[0077] Specifically, other aromatic dianhydrides can be selected from, for example, 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4-BPDA), 2,3,3′,4′-biphenyltetracarboxylic dianhydride (3,4-BPDA), 2,2′,3,3′-biphenyltetracarboxylic dianhydride (3,3-BPDA), 4,4′-(hexafluoroisopropylidene) phthalic anhydride (6FDA), 3,4′-oxobisphthalic anhydride (3,4-ODPA), 4,4′-oxobisphthalic anhydride (4,4-ODPA), 4,4′-sulfonyl phthalic anhydride (SDPA), (isopropylidene diphenoxy) bis(o- One or more of the following dianhydrides containing an aromatic ring, or mixtures thereof: phthalic anhydride (BPADA), pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), bis(carboxyphenyl)dimethylsilane dianhydride (SIDA), 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride (DSDA), N-[4-[4-[(1,3-dioxo-2-benzofuran-5-carbonyl)amino]-2-(trifluoromethyl)phenyl]-3-(trifluoromethyl)phenyl]-1,3-dioxo-2-benzofuran-5-carboxamide (TA-TFMB) or derivatives thereof.

[0078] Other dianhydrides may also be selected from alicyclic dianhydrides. These alicyclic dianhydrides can be any alicyclic dianhydride commonly used in the art, and the type is not limited. The alicyclic dianhydride refers to a dianhydride containing at least one alicyclic ring, which may be a monocyclic ring, or two or more fused alicyclic rings, or two or more alicyclic rings connected by a single bond, a substituted or unsubstituted C1-5 alkylene group, O, or C=O.

[0079] Specifically, the alicyclic dianhydride may be, for example, one or more alicyclic dianhydrides selected from 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (HPMDA), 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride (DMCBDA), norcamphene-2-spiro-α-cyclopentanone-α′-spiro-2"-norcamphene-5,5″,6,6″-tetracarboxylic dianhydride (CpODA) and their derivatives, or mixtures thereof. More specifically, the alicyclic dianhydride may comprise 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA).

[0080] When the alicyclic dianhydride forms a non-conjugated structure in the polymer chain, the formation of charge-transfer complexes can be effectively reduced, thereby improving optical and physical properties.

[0081] When further comprising aromatic dianhydrides and / or alicyclic dianhydrides other than BPAF, the mixing ratio is not limited. However, for example, based on the total molar number of the aromatic dianhydrides (units derived from aromatic dianhydrides) and alicyclic dianhydrides (units derived from alicyclic dianhydrides), the content of alicyclic dianhydrides (units derived from alicyclic dianhydrides) can be 1 mol% or more, 2 mol% or more, 5 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 55 mol% or more, 60 mol% or more, or 70 mol% or more, and can be 99 mol% or less, 98 mol% or less, 95 mol% or less, 90 mol% or less, 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, 60 mol% or less, or 50 mol% or less. However, it is not limited to the above ranges.

[0082] The above content range is an example exemplified to meet the desired physical properties and can be varied depending on the composition of the monomer, and is not limited thereto.

[0083] According to one specific embodiment, the liquid composition provided by the present invention comprises the aforementioned polyimide precursor and / or polyimide, and a solvent.

[0084] The liquid composition may contain a commonly used solvent. The solvent may be an organic solvent, specifically a polar solvent, and more specifically, a combination of two or more selected from N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethyl cellosolve, methyl cellosolve, acetone, ethyl acetate, m-cresol, 1,4-dioxane, γ-butyrolactone (GBL), and their derivatives, but is not limited thereto.

[0085] The polyimide precursor provided by the present invention can be dissolved in the solvent to form a liquid composition; and the polyimide provided by the present invention also has good solubility in the solvent, and therefore can also form a liquid composition.

[0086] The liquid composition described herein can be used to form polyimide films. Based on the good solubility of the polyimide provided by this invention, it has good processability, and polyimide films can be directly formed using the liquid composition based on the polyimide.

[0087] In addition to the components described above, the composition may also contain additives as needed. These additives may be for improving film formation, adhesion, optical and physical properties, mechanical and physical properties, flame retardancy, etc., and may include, for example, flame retardants, tackifiers, inorganic particles, antioxidants, UV stabilizers, and / or plasticizers, but are not limited thereto.

[0088] The composition can be prepared by precipitation after the addition of all monomers comprising the aromatic diamine and the aromatic dianhydride.

[0089] According to one specific embodiment, the polyimide film provided by the present invention comprises the polyimide described above, or is obtained by curing the liquid composition described above.

[0090] At this point, the total transmittance of the polyimide film according to a specific embodiment, measured in the 360-780nm range according to ASTM D1003 standard, may be 80.0% or higher, 84.0% or higher, 87.0% or higher, 87.5% or higher, 88.0% or higher, 88.3% or higher, 88.5% or higher, 89.0% or higher, 89.5% or higher, or 90.0% or higher, but is not necessarily limited to these values.

[0091] Furthermore, the haze of the polyimide film according to a specific embodiment, as measured according to ASTM D1003, may be less than 2.0%, less than 1.5%, less than 1.3%, less than 1.2%, less than 1.0%, less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, or less than 0.4%, but is not necessarily limited to these.

[0092] Furthermore, the yellow index of the polyimide film according to a specific embodiment, as measured according to ASTM E313, may be less than 15.0, less than 14.5, less than 12.0, less than 10.0, less than 7.0, less than 6.5, less than 6.0, less than 5.8, less than 5.5, less than 5.0, less than 4.5, or less than 4.0, but is not necessarily limited to this.

[0093] Furthermore, according to a specific embodiment of the polyimide film, the modulus measured according to ASTM D882 standard can be above 4.0 GPa, above 4.5 GPa, above 5.0 GPa, above 5.5 GPa, above 6.0 GPa, above 6.5 GPa, above 6.8 GPa, above 7.0 GPa, above 7.5 GPa, above 8.0 GPa, or above 9.5 GPa.

[0094] The physical properties of the polyimide can be obtained by measuring a polyimide film that has undergone a drying process at 80-100°C, 85-95°C, or about 90°C, or by measuring a polyimide film that has undergone a drying process at a high temperature of 110-160°C, 120-160°C, 130-150°C, or about 140°C.

[0095] According to one specific embodiment, the polyimide film is prepared by utilizing a liquid composition comprising the polyimide precursor and / or polyimide described in this invention, wherein the polyimide precursor and / or polyimide comprises a combination of units derived from a compound of formula III-1 and units derived from BPAF, thereby providing a film that simultaneously meets the desired physical properties of a transmittance of ≥87.0%, a haze of ≤2.0%, a yellowness index of ≤15.0, and a modulus of ≥4.0 GPa.

[0096] The thickness of the polyimide film can be 1-500μm, 10-250μm, 10-100μm, 20-100μm or 20-80μm, but is not necessarily limited to these.

[0097] According to one specific embodiment, the polyimide film can be prepared by coating a liquid composition comprising a polyimide precursor and / or polyimide and a solvent of the above embodiment onto a substrate, followed by drying and / or stretching, or by a solution casting method.

[0098] More specifically, the preparation may include the following steps: imidizing the polyimide precursor of one embodiment above to prepare a polyimide resin; and coating a resin composition solution in which the polyimide resin is dissolved in an organic solvent to form a film.

[0099] The organic solvent may be, for example, any one or more polar solvents selected from N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethyl cellosolve, methyl cellosolve, acetone, ethyl acetate, m-cresol, 1,4-dioxane, γ-butyrolactone (GBL) and their derivatives, but is not necessarily limited thereto.

[0100] The imidization can be carried out chemically using one or more of an imidization catalyst and a dehydrating agent. The imidization catalyst can be one or more of a pyridine, isoquinoline, and β-quinoline. Furthermore, the dehydrating agent can be one or more of a acetic anhydride, phthalic anhydride, and maleic anhydride. The imidization catalyst and dehydrating agent can be any commonly used imidization catalyst and dehydrating agent, and are not necessarily limited to the types mentioned above.

[0101] Furthermore, in the step of preparing the polyimide resin, additives such as flame retardants, tackifiers, inorganic particles, antioxidants, UV stabilizers, and plasticizers can be mixed into the polyimide precursor (i.e., polyamic acid) solution to prepare the polyimide resin. Additionally, after imidization, the resin is purified using a solvent to obtain a solid compound, and this solid compound is dissolved in the solvent to obtain a polyimide resin composition. In this case, the solvent may contain, for example, DMAc, but is not limited to this.

[0102] The film-forming step involves coating a polyimide resin composition onto a substrate and then heat-treating it to form a film. The substrate can be, for example, glass, stainless steel, or film. Coating can be performed using a die coater, air knife coating, reverse roller coating, spraying, blade coating, casting, gravure coating, spin coating, etc.

[0103] The heat treatment can be performed in steps, for example. It can be carried out by a stepwise heat treatment, involving a primary drying at 70-160°C for 1 minute to 2 hours followed by a secondary drying at 150-450°C for 1 minute to 2 hours. However, it is not necessarily limited to the above-mentioned temperature and time conditions. For example, the primary drying can be performed at 25-220°C, 80-150°C, 70-110°C, 130-150°C, 90°C, 120°C, or 140°C for 1-300 minutes, 10-150 minutes, 10-90 minutes, 20-60 minutes, or 30 minutes, respectively; and the secondary drying can be performed at 200-500°C, 200-300°C, 220-300°C, or 250-300°C for 1-300 minutes, 10-150 minutes, 10-90 minutes, 30-90 minutes, or 40-80 minutes, respectively. In this case, during the step-by-step heat treatment, the temperature can preferably be increased within the range of 1-20°C / min during the transition between each step. Furthermore, the heat treatment can be carried out in a separate vacuum oven or an oven filled with inert gas, etc., and is not necessarily limited to these methods. Additionally, coating can be performed using an applicator to form a film on the support.

[0104] According to one specific embodiment, the polyimide film has the effect of suppressing optical degradation (clouding) even when the drying process is carried out at a high temperature of about 140°C during the first drying, thus ensuring productivity sufficient for mass production.

[0105] The following examples and experimental cases are illustrated in detail. However, the examples and experimental cases described below are only for illustrating a part of a specific implementation and should not be construed as limiting the technology described herein.

[0106] Measurement methods

[0107] 1. Light transmittance (total light transmittance)

[0108] For the membranes prepared in this paper, the total transmittance (%) was measured in the entire wavelength range of 360–780 nm using an UltraScan VIS spectrophotometer (Hunter Lab, USA) with the CIE standard light source D65.

[0109] 2. Haze

[0110] For the membranes prepared in this paper, the haze value (%) was measured using a CIE standard light source D65 and an UltraScan VIS spectrophotometer (Hunter Lab, USA).

[0111] 3. Yellow Index (YI)

[0112] For the membranes prepared in this paper, the yellow index was measured using a CIE standard light source D65 and an UltraScan VIS spectrophotometer (Hunter Lab, USA).

[0113] 4. Modulus

[0114] For the polyamide-imide films with a length of 50 mm and a width of 10 mm prepared in the examples and comparative examples, the modulus (GPa) was measured under the condition of stretching at 2 mm / min at 25°C.

[0115] Example 1

[0116] This embodiment provides a soluble polyimide and its preparation method:

[0117] Under nitrogen protection, compound III-1, BPAF, and m-cresol were added to a three-necked flask and stirred at 100°C until completely dissolved (<2h). A water separator was then installed, and the mixture was slowly heated to 185°C and reacted for another 2h to obtain a red, viscous first polyimide solution. The polyimide solution was cooled to room temperature, and then pyromellitic dianhydride (PMDA) and 20 mol% benzoic acid were added. The mixture was stirred at 100°C until completely dissolved (<2h), and a water separator was then installed. The temperature was slowly increased to 185℃ and the reaction was continued for 10 hours to obtain a second polyimide solution. The molar ratio of BPAF to PMDA was 80:20, and the total molar ratio of BPAF and PMDA to the molar ratio of compound III-1 was 1:1. The second polyimide solution was added dropwise to 5 times the amount of ethanol to obtain white fibrous polyimide. After purification, the polyimide was dissolved in N,N-dimethylacetamide (DMAc) to obtain a 10.0% by weight polyimide solution.

[0118] The 10.0% by weight polyimide solution obtained above was filtered through a filter, coated onto a clean glass substrate, softened on a hot plate at 90°C, placed in a nitrogen-purged oven and heated in stages to the maximum curing temperature, the glass plate was removed from the oven, immersed in water and manually delaminated to obtain a polyimide film sample.

[0119] Example 2

[0120] This embodiment provides a polyimide precursor (polyamic acid) and its preparation method:

[0121] Under a nitrogen atmosphere and with a mechanical stirrer, N,N-dimethylacetamide (DMAC) and compound III-1 were added to a reactor and stirred thoroughly. Then, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) was added and stirred thoroughly until dissolved. After that, 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4-BPDA) was added to obtain a mixed reaction system, wherein the total molar ratio of BPAF and 4,4-BPDA to compound III-1 was 1:1, and the molar ratio of BPAF to 4,4-BPDA was 30:70.

[0122] The reactor temperature was maintained below 50°C, and the mixed reaction system was stirred for 24 hours to dissolve and react, forming a polyamic acid solution. During the polymerization reaction, an appropriate amount of DMAC was added to adjust the viscosity of the solution, ensuring that the solution remained uniform and free of foaming. Finally, the polyamic acid content was controlled to be 10.0% by weight.

[0123] The obtained polyamic acid solution was filtered through a filter, coated onto a clean glass substrate, softened on a hot plate at 90°C, and then placed in a nitrogen-purged oven and heated in stages to the maximum curing temperature. The glass plate was then removed from the oven, immersed in water, and manually delaminated to obtain a polyimide film sample.

[0124] Example 3

[0125] The polyamic acid solution was prepared using the same method as in Example 2, except that the molar ratio of BPAF to 4,4-BPDA was 50:50.

[0126] Acetic anhydride (the amount of acetic anhydride added is 2-3 times the theoretical amount of ammonium functional groups) and pyridine (the amount of pyridine added is 2-3 times the theoretical amount of ammonium functional groups) are added to the obtained polyamic acid solution to obtain a mixed reaction system. The mixed reaction system is stirred for 24 hours to carry out the reaction and obtain a polyimide solution, which is transparent.

[0127] The polyimide solution was added dropwise to 5 times the volume of ethanol to obtain white fibrous polyimide. After purification, the polyimide was dissolved in DMAC to obtain a 10.0% by weight polyimide solution. The solution was filtered and coated onto a clean glass substrate. It was then softened on a hot plate at 90°C and placed in a nitrogen-purged oven. The substrate was heated in stages to the maximum curing temperature. The glass substrate was then removed from the oven, immersed in water, and manually delaminated to obtain a polyimide film sample.

[0128] Examples 4 to 24

[0129] Examples 4 to 24 differ from Example 3 only in that the dianhydride (different aromatic dianhydrides), diamine monomer and their amounts are changed according to Table 1, while the rest are the same as in Example 1.

[0130] Examples 25 to 28

[0131] Examples 24 to 28 differ from Example 2 only in that the dianhydride (for different alicyclic dianhydrides), diamine monomer, and their amounts are varied as shown in Table 1, while the rest are the same as in Example 1.

[0132] Examples 29 to 41

[0133] Examples 29 to 41 differ from Example 2 only in that the dianhydride, diamine monomer (different aromatic diamines) and their amounts are varied as shown in Table 1, while the rest are the same as in Example 1.

[0134] Examples 42 to 47

[0135] Examples 42 to 47 differ from Example 1 only in that the dianhydride, diamine monomer (IV-1), and their amounts are varied as shown in Table 1, while the rest are carried out in the same manner as Example 1.

[0136] Examples 48 to 82

[0137] Examples 48 to 82 differ from Example 2 only in that the dianhydrides (including aromatic and alicyclic dianhydrides), diamine monomers, and their amounts are varied as shown in Table 1, while the rest are carried out in the same manner as in Example 2.

[0138] Example 83

[0139] The only difference between Example 83 and Example 1 is that the dianhydride (including three aromatic dianhydrides), diamine monomer and their amounts are changed according to Table 1, while the rest are the same as in Example 1. Figure 1 This is the DMA test curve of the polyimide film in this embodiment; Figure 2 This is the TMA test curve of the polyimide film in this embodiment.

[0140] Examples 84 to 91

[0141] Examples 83 to 91 differ from Example 1 in that the synthesis is carried out in the same manner as Example 1, except that the compounds of Formula III, dianhydrides, diamine monomers and their amounts are changed according to Table 1.

[0142] Examples 92 to 102

[0143] Examples 92 to 102 differ from Example 1 in that the synthesis is carried out according to the transformation of compound IV, dianhydride, diamine monomer and their amounts as shown in Table 1, while the rest are the same as in Example 1.

[0144] Comparative Example 1

[0145] The only difference between Comparative Example 1 and Example 1 is that only 6 FDA was used for the dianhydride; otherwise, the procedures were the same as in Example 1.

[0146] Comparative Example 2

[0147] The only difference between Comparative Example 2 and Example 1 is that the molar ratio of 6FDA to PMDA in dianhydride is 2:98, while the rest of the procedures are the same as in Example 1.

[0148] Comparative Example 3

[0149] The only difference between Comparative Example 3 and Example 1 is that 6FDA was used instead of dianhydride and diamine was replaced with IV-1. The rest of the procedures were the same as in Example 1.

[0150] Comparative Example 4

[0151] The only difference between Comparative Example 4 and Example 1 is that the molar ratio of 6FDA:PMDA in the dianhydride is 2:98, and the diamine is replaced with IV-1. The rest of the procedures are the same as in Example 1.

[0152] Comparative Example 5

[0153] The only difference between Comparative Example 5 and Example 1 is that the molar ratio of 6FDA:4,4-BPDA in the dianhydride is 50:50, and the molar ratio of III-1:TFMB in the diamine is 2:98. The rest of the procedures are the same as in Example 1.

[0154] Comparative Example 6

[0155] The only difference between Comparative Example 6 and Example 1 is that the molar ratio of 6FDA to 4,4-BPDA in the dianhydride is 50:50, and the molar ratio of IV-1 to TFMB in the diamine is 2:98. The rest of the procedures are the same as in Example 1.

[0156] Comparative Example 7

[0157] The only difference between Comparative Example 7 and Example 1 is that the molar ratio of PMDA to 4,4-BPDA in the dianhydride is 50:50, and the molar ratio of IV-1 to TFMB in the diamine is 50:50. The rest of the procedures are the same as in Example 1.

[0158] Table 1. Dianhydride, diamine monomers and their contents used in the embodiments of the present invention.

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] Table 2. Curing temperature and related properties of the polyimide films in the embodiments and comparative examples of the present invention.

[0165]

[0166]

[0167]

[0168]

[0169] Note: The curing temperature in Table 2 represents the maximum curing temperature; T d1％ Temperature representing 1% weight loss; average transmittance test range is 360-780 nm.

[0170] The results of the solubility tests of the polyimides prepared in Examples 1-102 and Comparative Examples 1-7 in different solvents are shown in Table 3. Test conditions: 10 mg of the sample was dissolved in 1 mL of solvent at room temperature or after heating, and the solubility was observed after standing for 24 hours. In Table 1, "++" indicates soluble at room temperature; "+" indicates soluble upon heating to the boiling point; and "+-" indicates partially soluble even upon heating to the boiling point.

[0171] Table 3. Solubility of polyimides in relevant solvents in the examples and comparative examples.

[0172]

[0173]

[0174]

[0175] It should be noted that not all of the operations described above in the general description or examples are necessary; some specific operations may not be necessary, and one or more other operations may be performed in addition to those described. Furthermore, the order of the listed operations does not necessarily represent the order in which they are performed.

[0176] Those skilled in the art will understand that various modifications and changes can be made without departing from the scope of the invention as defined in the claims. Therefore, the specification and drawings should be considered exemplary rather than limiting, and all such modifications are included within the scope of the invention.

[0177] The benefits, other advantages, and solutions to problems have been described above with reference to specific embodiments. However, the benefits, advantages, solutions to problems, and any one or more features that may cause any benefit, advantage, or solution to appear or make it more apparent shall not be construed as key, essential, or fundamental features of any or all claims.

[0178] It should be understood that, for clarity, certain features described herein in the context of individual embodiments may also be provided in combination in a single embodiment. Conversely, for brevity, the various features described in the context of a single embodiment may also be provided individually or in any sub-combination. The use of numerical values ​​within the various ranges specified herein is expressed as approximations, as if both the minimum and maximum values ​​within the range were preceded by the expression "approximately". In this way, slightly higher and lower than the ranges reached can achieve substantially the same results as values ​​within these ranges. Moreover, the disclosure of these ranges is intended as a continuous range including each value between the minimum and maximum average values, including fractional values ​​that may be produced when some components of a value are mixed with components of different values. Furthermore, when wider and narrower ranges are disclosed, it is in the intention of the invention to match the minimum value from one range with the maximum value from another range, and vice versa.

Claims

1. A polyimide precursor, characterized by: The polyimide precursor has a repeating unit structure shown in Formula I, ； wherein R a represents a tetracarboxylic dianhydride component residue including a combination of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residue and 3,3',4,4'-biphenyltetracarboxylic dianhydride component residue, optionally pyromellitic dianhydride component residue, wherein the mole percentage of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride component residue is 20 to 50 mol% of the tetracarboxylic dianhydride component residue; R b Represents aromatic diamine residues, forming R b The aromatic diamine monomer includes 60 mol% of at least one of the diamine compounds represented by formulas III-1 to III-9, and 40 mol% of 2,2'-bis(trifluoromethyl)benzidine; 。 2. A polyimide, characterized by: The polyimide has a repeating unit structure shown in Formula II: ； wherein R a represents a tetracarboxylic dianhydride component residue including a combination of a 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride component residue and a 3,3',4,4'-biphenyltetracarboxylic dianhydride component residue, optionally a pyromellitic dianhydride component residue, wherein the mole percentage of the 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride component residue is 20 to 50 mol% of the tetracarboxylic dianhydride component residue; R b Represents aromatic diamine residues, forming R b The aromatic diamine monomer includes 60 mol% of at least one of the diamine compounds represented by formulas III-1 to III-9, and 40 mol% of 2,2'-bis(trifluoromethyl)benzidine; 。 3. The polyimide of claim 2, wherein: The solubility of the polyimide in the following solvents is 2-40 wt%, the solvents including a combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-pyrrolidone, dimethyl sulfoxide, m-cresol, 1,4-dioxane, gamma-butyrolactone.

4. The polyimide of claim 2, wherein: The polyimide has a glass transition temperature Tg g greater than 450 o C.

5. The polyimide of claim 2, wherein: The yellow index YI value of the polyimide is less than 15.

0.

6. The method of producing the polyimide precursor according to claim 1, characterized by, Comprising: The first mixed reaction system containing the tetracarboxylic dianhydride, aromatic diamine and solvent is subjected to a polymerization reaction under a temperature condition of -10 ~ 80℃ to obtain the polyimide precursor.

7. The method of claim 6, wherein: The molar ratio of the tetracarboxylic dianhydride to the aromatic diamine is 0.98 ~ 1.02: 0.98 ~ 1.

02.

8. The process for the preparation of the polyimide according to any one of claims 2 to 5, characterized in that: The preparation method includes a chemical method and a solvothermal method; The chemical method includes: subjecting the polyimide precursor of claim 1 to imidization to obtain the polyimide; The solvothermal method includes: performing a polymerization reaction on a second mixed reaction system containing the tetracarboxylic dianhydride, the aromatic diamine, and a solvent at a temperature condition of 150 ~ 220 o C to obtain the polyimide.

9. The production method according to claim 8, characterized by, In the solvothermal method, the molar ratio of the tetracarboxylic dianhydride to the aromatic diamine is 0.98 ~ 1.02: 0.98 ~ 1.

02.

10. A liquid composition characterized in that, Comprising: The polyimide precursor of claim 1 and / or the polyimide of any one of claims 2-5; At least one aprotic solvent.

11. The liquid composition according to claim 10, characterized in that: The aprotic solvent includes a combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-pyrrolidone, dimethyl sulfoxide, m-cresol, 1,4-dioxane, gamma-butyrolactone.

12. A polyimide film characterized by, The polyimide film is obtained by curing the liquid composition of any one of claims 10-11.

13. The polyimide film according to claim 12, characterized by: said polyimide film having a thickness of 10 μm has a glass transition temperature greater than 450 o a glass transition temperature of C and a yellowness index of less than 15.0; And / or, the total light transmittance of the polyimide film in the wavelength range of 360-780 nm is 80.0% or more; And / or, the haze of the polyimide film is 2.0% or less; And / or, the modulus of the polyimide film is 4.0 GPa or more.

14. A transparent structure, characterized by: The transparent structure includes the polyimide film of claim 12 or 13.

15. An apparatus having a transparent component, characterized by The device includes the transparent structure of claim 14.

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