Polyimide precursor comprising eco-friendly solvent and polyimide film having excellent substrate adhesion and excellent heat resistance characteristics manufactured therefrom

Abstract

The present invention provides a polyimide precursor comprising: a polyamic acid including a dianhydride monomer and a diamine monomer as polymerization units; and an eco-friendly solvent, wherein the diamine monomer includes a first diamine monomer and a second diamine monomer, the first diamine monomer is different from the second diamine monomer, the second diamine monomer includes 3,4'-diaminodiphenylether (3,4'-ODA), and the diamine monomer includes 80-99.9 mol% of the first diamine monomer and 0.01-20 mol% of the second diamine monomer with respect to a total of 100 mol% of the diamine monomer.

Description

Polyimide precursor containing an eco-friendly solvent and polyimide film manufactured therefrom having excellent substrate adhesion and excellent heat resistance properties

[0001] The present invention relates to a polyimide precursor comprising an environmentally friendly solvent and a polyimide film manufactured therefrom, which has excellent substrate adhesion and excellent heat resistance. More particularly, the present invention relates to a polyimide precursor comprising 3,4'-diaminodiphenyl ether (3,4'-ODA) and a polyimide film manufactured therefrom, which has excellent substrate adhesion and excellent heat resistance.

[0002] Polyimide (PI) is a polymer material characterized by excellent heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials, based on a rigid aromatic backbone and an imide ring with excellent chemical stability. It can be manufactured into various forms, such as films, fibers, and membranes. These properties make polyimide widely used in advanced materials and insulating coatings for electrical and electronic applications, semiconductors, displays, automobiles, aviation, and space applications.

[0003] Specifically, for display applications, polyimide must be transparent. To reduce the defect rate due to residual stress on the substrate during the heat treatment process for display manufacturing, its coefficient of thermal expansion must not be negative at temperatures above 350°C. Furthermore, for display applications, polyimide must exhibit excellent adhesion to silicon wafers, glass, or metal.

[0004] Meanwhile, polyimides can be manufactured by dissolving an acid dianhydride having two acid anhydride groups per molecule and a diamine having two amino groups per molecule in a solvent, synthesizing a polyimide precursor called polyamic acid (PAA), followed by coating, drying, and heat treating at a temperature of about 350°C to imidize. In this case, polyimides are manufactured in solvents currently classified as hazardous, such as N-methylpyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc). NMP is a particularly good solvent for certain polyimide or polyamic acid polymers, dissolving such polymers that other solvents cannot. However, NMP is a reproductive toxicant, or reprotoxin. In the electronics industry, many polymer applications require spin coating, slot-die coating, or other deposition techniques that require the polymer to remain in solution until the solvent is removed for film casting. The viscosity of such polymer compositions must be compatible with these deposition techniques. This requirement limits the range of solvents available for polyimides. A need exists for a suitable solvent to replace NMP for use with polyimides in the manufacture of electronic devices.

[0005] Therefore, there is a need to develop a polyimide that maintains the basic properties of current polyimide while having high substrate adhesion and excellent heat resistance, and is manufactured using a suitable solvent that can replace NMP.

[0006] The present inventors have completed the present invention by confirming that a polyimide precursor containing 3,4'-ODA and a polyimide film produced therefrom have excellent appearance (no bubbles), high substrate adhesion, and excellent heat resistance.

[0007] The present invention aims to provide a polyimide precursor using an environmentally friendly solvent and having excellent appearance (no bubbles), high substrate adhesion, and excellent heat resistance, and a polyimide film manufactured therefrom.

[0008] In addition, the present invention aims to provide a transparent polyimide precursor for a display and a polyimide film manufactured therefrom.

[0009] The polyimide precursor according to the present invention and the polyimide film manufactured therefrom utilize an environmentally friendly solvent and have the effects of excellent appearance (no bubbles), high substrate adhesion, and excellent heat resistance.

[0010] Specifically, the polyimide precursor according to the present invention and the polyimide film manufactured therefrom include 3,4'-ODA, which causes a polymer chain having a more linear structure than 4,4'-ODA, thereby increasing the packing density of the polymer chain, and as the packing density increases, there is an effect of having higher substrate adhesion and superior heat resistance properties.

[0011] In addition, the polyimide precursor according to the present invention and the polyimide film manufactured therefrom have an effect that can be applied to displays.

[0012] The present invention is susceptible to various modifications and embodiments. Therefore, specific embodiments are illustrated and described in detail. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0013] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0014] When amounts, concentrations, or other values ​​or parameters are given herein as a range, preferred range, or enumeration of an upper preferred value and a lower preferred value, it should be understood that this specifically discloses any range formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed.

[0015] When a range of numerical values ​​is mentioned in this specification, unless otherwise stated, it is intended that the endpoints of the range and the scope of the invention within the range are not limited to the specific values ​​mentioned in defining the range.

[0016] As used herein, "dianhydride" is intended to include precursors or derivatives thereof, also referred to as "dianhydric acids," "dianhydrides," or "acid dianhydrides." While these may not technically be dianhydrides, they will nonetheless react with diamines to form polyamic acids, which can then be converted to polyimides.

[0017] As used herein, "diamine" is intended to include precursors or derivatives thereof, which may not technically be diamines, but which will nonetheless react with a dianhydride acid to form a polyamic acid, which in turn can be converted to a polyimide.

[0018] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be construed in an idealized or overly formal sense unless explicitly defined herein. Specific details for implementing the invention are described below.

[0019] The present invention relates to a polyimide precursor containing an environmentally friendly solvent and a polyimide film manufactured therefrom having excellent substrate adhesion and excellent heat resistance properties.

[0020] polyimide precursor

[0021] The present invention provides a polyimide precursor comprising a polyamic acid comprising a dianhydride monomer and a diamine monomer as polymerization units; and an eco-friendly solvent; wherein the diamine monomer comprises a first diamine monomer and a second diamine monomer, the first diamine monomer and the second diamine monomer are different from each other, the second diamine monomer comprises 3,4'-diaminodiphenyl ether (3,4'-ODA), and the diamine monomer comprises 80 to 99.9 mol% of the first diamine monomer and 0.01 to 20 mol% of the second diamine monomer based on 100 mol% of the total of the diamine monomers.

[0022] Specifically, the diamine monomer may contain 80 to 99.9 mol% of the first diamine monomer based on 100 mol% of the total diamine monomer, and for example, the lower limit may be 83 mol% or more, 85 mol% or more, 87 mol% or more, 90 mol% or more, 91 mol% or more, 92 mol% or more, 93 mol% or more, 94 mol% or more, or 95 mol% or more, and the upper limit may be 99.7 mol% or less, 99.5 mol% or less, 99 mol% or less, 98.7 mol% or less, 98.5 mol% or less, 98.3 mol% or less, 98 mol% or less, 97.7 mol% or less, 97.5 mol% or less, 97.3 mol% or less, 97.2 mol% or less, 97.1 mol% or less, or 97 mol% or less.

[0023] The above diamine monomer may contain 0.01 to 20 mol% of the second diamine monomer based on 100 mol% of the total diamine monomer, and for example, the lower limit may be 0.03 mol% or more, 0.05 mol% or more, 1 mol% or more, 1.3 mol% or more, 1.5 mol% or more, 1.7 mol% or more, 2 mol% or more, 2.3 mol% or more, 2.5 mol% or more, 2.7 mol% or more, 2.8 mol% or more, 2.9 mol% or more, or 3 mol% or more, and the upper limit may be 17 mol% or less, 15 mol% or less, 13 mol% or less, 10 mol% or less, 9 mol% or less, 8 mol% or less, 7 mol% or less, 6 mol% or less, or 5 mol% or less.

[0024] When the first diamine monomer is less than 80 mol% (the second diamine monomer is more than 20 mol%) based on 100 mol% of the total diamine monomer, the substrate adhesion of the produced polyimide film is low and the heat resistance is poor, which is undesirable. When the first diamine monomer is more than 99.9 mol% (the second diamine monomer is less than 0.01 mol%), the substrate adhesion and heat resistance of the produced polyimide film are poor, which is undesirable.

[0025] The above-mentioned eco-friendly solvent may include at least one selected from the group consisting of dimethylpropionamide (DMPA), 3-methoxy-N,N-dimethylpropanamide, tetramethyl urea (TMU), N-ethyl-2-pyrrolidone (NEP), and diethyl formamide (DEF), and preferably may include dimethylpropionamide (DMPA). The DMPA is an eco-friendly organic solvent that can be processed without a separate purification process after the polymerization reaction, thereby reducing costs.

[0026] The above dianhydride monomers are biphenyl tetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), bis(3,4-dicarboxyphenyl)sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-Phenylenebis(trimellitic monoester acid anhydride), p-Biphenylenebis(trimellitic monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-Bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-Bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-Bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-Bis〔(3,4-dicarboxy phenoxy)phenyl〕propane dianhydride (BPADA), 2,3,6,7-naphthalene tetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic It may include at least one selected from the group consisting of dianhydride and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride, and preferably biphenyl tetracarboxylic dianhydride (BPDA).

[0027] The above first diamine monomer is 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (4,4'-ODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2-bisaminophenoxyphenylpropane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-Diaminodiphenylmethane, 4,4'-Diaminodiphenylmethane, 2,2-Bis(3-aminophenyl)propane, 2,2-Bis(4-aminophenyl)propane, 2,2-Bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-Bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-Diaminodiphenylsulfoxide, 3,4'-Diaminodiphenylsulfoxide, 4,4'-Diaminodiphenylsulfoxide, 1,3-Bis(3-aminophenyl)benzene, 1,3-Bis(4-aminophenyl)benzene, 1,4-Bis(3-aminophenyl)benzene, 1,4-Bis(4-aminophenyl)benzene, 1,3-Bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-Diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis〔2-(4-aminophenyl)isopropyl〕benzene, 1,4-bis〔2-(3-aminophenyl)isopropyl〕benzene, 1,4-bis〔2-(4-aminophenyl)isopropyl〕benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-Bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis〔3-(3-aminophenoxy)phenyl〕ether, bis〔3-(4-aminophenoxy)phenyl〕ether, bis〔4-(3-aminophenoxy)phenyl〕ether, bis〔4-(4-aminophenoxy)phenyl〕ether, bis〔3-(3-aminophenoxy)phenyl〕ketone, bis〔3-(4-aminophenoxy)phenyl〕ketone, bis〔4-(3-aminophenoxy)phenyl〕ketone, bis〔3-(3-aminophenoxy)phenyl〕sulfide, bis〔3-(4-aminophenoxy)phenyl〕sulfide, Bis〔4-(3-aminophenoxy)phenyl〕sulfide, bis〔4-(4-aminophenoxy)phenyl〕sulfide, bis〔3-(3-aminophenoxy)phenyl〕sulfone, bis〔3-(4-aminophenoxy)phenyl〕sulfone, bis〔4-(3-aminophenoxy)phenyl〕sulfone, bis〔4-(4-aminophenoxy)phenyl〕sulfone, bis〔3-(3-aminophenoxy)phenyl〕methane, bis〔3-(4-aminophenoxy)phenyl〕methane, bis〔4-(3-aminophenoxy)phenyl〕methane, bis〔4-(4-aminophenoxy)phenyl〕methane, 2,2-bis〔3-(3-aminophenoxy)phenyl〕propane, 2,2-bis〔3-(4-aminophenoxy)phenyl〕propane, 2,2-bis〔4-(3-aminophenoxy)phenyl〕propane, 2,2-bis〔3-(3-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane, 2,2-bis〔3-(4-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane, 2,It may include at least one selected from the group consisting of 2-bis〔4-(3-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane and 2,2-bis〔4-(4-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane, and preferably at least one selected from the group consisting of 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (4,4'-ODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) and 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), and more preferably 1,4-diaminobenzene (PPD). When the first diamine monomer includes 1,4-diaminobenzene (PPD), a polyimide film manufactured from the polyimide composition has excellent heat resistance properties.

[0028] Even more preferably, the dianhydride monomer may be biphenyl tetracarboxylic dianhydride (BPDA), the first diamine monomer may be 1,4-diaminobenzene (PPD), and the second diamine monomer may be 3,4'-diaminodiphenyl ether (3,4'-ODA). When the dianhydride monomer is biphenyl tetracarboxylic dianhydride (BPDA), the first diamine monomer is 1,4-diaminobenzene (PPD), and the second diamine monomer is 3,4'-diaminodiphenyl ether (3,4'-ODA), a polyimide film manufactured from the polyimide composition has an effect of having excellent heat resistance properties.

[0029] The molar ratio of the above-mentioned dihydride monomer and the above-mentioned diamine monomer may be 1:2 to 2:1, and preferably 1:1.

[0030] The polyamic acid may contain 95 to 105 mol% of the dianhydride monomer based on 100 mol% of the diamine monomer, and for example, the lower limit may be 95.5 mol% or more, 96 mol% or more, 96.5 mol% or more, 97 mol% or more, 97.5 mol% or more, 98 mol% or more, 98.5 mol% or more, 99 mol% or more, or 99.5 mol% or more, and the upper limit may be 105 mol% or less, 104 mol% or less, 103 mol% or less, 102 mol% or less, 101 mol% or less, or 100 mol% or less.

[0031] Another embodiment of the present invention provides a method for producing the polyimide precursor.

[0032] Method for manufacturing polyimide precursor

[0033] The present invention provides a method for producing a polyimide precursor, comprising the steps of producing a polyamic acid by polymerizing a dianhydride monomer and a diamine monomer in an eco-friendly solvent, and producing a polyimide precursor comprising a polyamic acid and an eco-friendly solvent; wherein the diamine monomer includes a first diamine monomer and a second diamine monomer, the first diamine monomer and the second diamine monomer are different from each other, the second diamine monomer includes 3,4'-diaminodiphenyl ether (3,4'-ODA), and the diamine monomer includes 80 to 99.9 mol% of the first diamine monomer and 0.01 to 20 mol% of the second diamine monomer based on 100 mol% of the total of the diamine monomers.

[0034] Specifically, the diamine monomer may contain 80 to 99.9 mol% of the first diamine monomer based on 100 mol% of the total diamine monomer, and for example, the lower limit may be 83 mol% or more, 85 mol% or more, 87 mol% or more, 90 mol% or more, 91 mol% or more, 92 mol% or more, 93 mol% or more, 94 mol% or more, or 95 mol% or more, and the upper limit may be 99.7 mol% or less, 99.5 mol% or less, 99 mol% or less, 98.7 mol% or less, 98.5 mol% or less, 98.3 mol% or less, 98 mol% or less, 97.7 mol% or less, 97.5 mol% or less, 97.3 mol% or less, 97.2 mol% or less, 97.1 mol% or less, or 97 mol% or less.

[0035] The above diamine monomer may contain 0.01 to 20 mol% of the second diamine monomer based on 100 mol% of the total diamine monomer, and for example, the lower limit may be 0.03 mol% or more, 0.05 mol% or more, 1 mol% or more, 1.3 mol% or more, 1.5 mol% or more, 1.7 mol% or more, 2 mol% or more, 2.3 mol% or more, 2.5 mol% or more, 2.7 mol% or more, 2.8 mol% or more, 2.9 mol% or more, or 3 mol% or more, and the upper limit may be 17 mol% or less, 15 mol% or less, 13 mol% or less, 10 mol% or less, 9 mol% or less, 8 mol% or less, 7 mol% or less, 6 mol% or less, or 5 mol% or less.

[0036] When the first diamine monomer is less than 80 mol% (the second diamine monomer is more than 20 mol%) based on 100 mol% of the total diamine monomer, the substrate adhesion of the produced polyimide film is low and the heat resistance is poor, which is undesirable. When the first diamine monomer is more than 99.9 mol% (the second diamine monomer is less than 0.01 mol%), the substrate adhesion and heat resistance of the produced polyimide film are poor, which is undesirable.

[0037] The step of manufacturing the above polyimide precursor may include (a) a step of mixing an dianhydride monomer in an environmentally friendly solvent to prepare a solution; and (b) a step of adding a first diamine monomer to the solution, and then adding a second diamine monomer, mixing them, and reacting them to prepare a solution including a polyamic acid.

[0038] The reaction of step (b) can be carried out at room temperature (20 to 25°C) for 4 to 24 hours, preferably 8 to 20 hours, more preferably 12 to 18 hours, and even more preferably 15 to 17 hours. By carrying out the reaction for 4 to 24 hours, a polyamic acid and / or polyimide having a target repeating unit can be formed, and when looking at the degree to which the production amount of polyamic acid increases with time, a solution containing polyamic acid can be efficiently prepared.

[0039] Another embodiment of the present invention provides a polyimide precursor manufactured by the method for manufacturing the polyimide precursor.

[0040] polyimide film

[0041] The present invention provides a polyimide film comprising a cured product of the polyimide precursor.

[0042] The thickness of the above polyimide film can be appropriately selected in consideration of the purpose, usage environment, physical properties, etc. of the polyimide film. For example, the thickness of the polyimide film can be 1 to 100 μm, 5 to 50 μm, 7 to 30 μm, 8 to 20 μm, or 9 to 15 μm, but is not limited thereto.

[0043] The adhesion of the polyimide film to the a-Si substrate may be 1.0 to 2.5 N / cm, for example, the lower limit of the adhesion may be 1.1 N / cm, 1.15 N / cm, 1.2 N / cm, 1.25 N / cm, 1.28 N / cm, 1.3 N / cm, 1.32 N / cm, 1.35 N / cm, 1.37 N / cm, 1.38 N / cm, 1.39 N / cm or 1.40 N / cm or more, and the upper limit of the adhesion may be 2.4 N / cm, 2.3 N / cm, 2.25 N / cm, 2.2 N / cm, 2.15 N / cm, 2.1 N / cm, 2.05 N / cm, 2.03 N / cm or 2.00 N / cm or less.

[0044] The above adhesive strength may be measured using INSTRON's UTM 5546 model under conditions of 90° Peel mode and Cross Head Speed ​​50 mm / min after cutting a polyimide film on an a-Si substrate to 100x10 mm.

[0045] The coefficient of thermal expansion (CTE) of the polyimide film may be 1 to 10 ppm / ℃, for example, the lower limit of the coefficient of thermal expansion may be 1.5 ppm / ℃, 1.8 ppm / ℃, 2.0 ppm / ℃, 2.3 ppm / ℃, 2.5 ppm / ℃, 2.7 ppm / ℃, 3.0 ppm / ℃, 3.2 ppm / ℃, 3.3 ppm / ℃, 3.4 ppm / ℃ or 3.5 ppm / ℃ or more, and the upper limit of the coefficient of thermal expansion may be 9.7 ppm / ℃, 9.5 ppm / ℃, 9.4 ppm / ℃, 9.3 ppm / ℃, 9.2 ppm / ℃, 9.1 ppm / ℃, 9.0 ppm / ℃, 8.9 ppm / ℃ or 8.8 ppm / ℃ or less.

[0046] The above coefficient of thermal expansion (CTE) may be obtained using a thermomechanical analyzer. Specifically, the polyimide film may be cut to a width of 5 mm and a length of 16 mm, and then, under a nitrogen atmosphere, a tension of 0.02 N is applied, the temperature is increased from room temperature to 470°C at a heating rate of 10°C / min, and then cooled again at a rate of 10°C / min, and the slope in the range from 100°C to 460°C may be measured.

[0047] The 1% thermal decomposition temperature (Td) of the above polyimide film may be 300 to 600°C, 350 to 600°C, 400 to 600°C, 450 to 600°C, 500 to 600°C, or 550 to 600°C.

[0048] The above 1% thermal decomposition temperature (Td) may be measured using a thermogravimetric analyzer. Specifically, the polyimide film may be heated to 150°C at a rate of 10°C / min in a nitrogen atmosphere, then maintained isothermally for 30 minutes to remove moisture, and then heated to 600°C at a rate of 10°C / min to measure the temperature at which a 1% weight loss occurs.

[0049] Another embodiment of the present invention provides a display including the polyimide film.

[0050] To aid in understanding the present invention, examples are presented. The following examples are provided solely to facilitate a better understanding of the present invention, and the scope of the present invention is not limited by the examples.

[0051] <Example: Manufacturing of polyimide film>

[0052] Example 1

[0053] A solution was prepared by mixing 100 mol% of dimethylpropionamide (DMPA), an environmentally friendly solvent, and biphenyl tetracarboxylic dianhydride (BPDA) in a reactor.

[0054] Thereafter, 97 mol% of 1,4-diaminobenzene (PPD) was added to the solution, and then 3 mol% of 3,4'-diaminodiphenyl ether (3,4'-ODA) was added and mixed, and then reacted at 25°C for 16 hours to produce a polyimide precursor containing polyamic acid and an eco-friendly solvent (DMPA). Here, the dianhydride monomer (BPDA) and the diamine monomer (PPD and 3,4'-ODA) are used in equimolar amounts. Specifically, the dianhydride monomer is used in a total of 100 mol% based on a total of 100 mol% of the diamine monomer.

[0055] Next, using a spin-coater, the solvent and solid ratio was calculated, and the appropriate rpm and time were set to apply the polyimide precursor onto the a-Si sacrificial layer substrate. Thereafter, the temperature was increased from 120°C to 470°C at a rate of 10°C / min, maintained at 470°C for 45 minutes, and then cooled to 25°C to cure, thereby obtaining a polyimide film. At this time, the film thickness was manufactured to be 10 μm.

[0056] Examples 2 and 3

[0057] A polyimide film was manufactured in the same manner as in Example 1, except that the contents of each monomer were different, as shown in Table 1 below.

[0058] Comparative Examples 1 to 8

[0059] A polyimide film was manufactured in the same manner as in Example 1, except that the content and type of each monomer were different, as shown in Table 1 below.

[0060] Table 1 below shows the types and contents of monomers used in manufacturing polyimide films according to Examples 1 to 3 and Comparative Examples 1 to 8, and the thicknesses of the manufactured polyimide films.

[0061] Classification Anhydride Monomer System 1 Diamine 2 Diamine Thickness (μm) Type Content (mol%) Type Content (mol%) Type Content (mol%) Example 1 BPDA 100 PPD 97 3,4'-ODA 3 10.0 Example 2 95 3,4'-ODA 5 10.0 Example 3 80 3,4'-ODA 2 010.2 Comparative Example 1 100--10.0 Comparative Example 2 97 4,4'-ODA 3 9.9 Comparative Example 3 95 4,4'-ODA 5 10.2 Comparative Example 4 97 TFMB 39.9 Comparative Example 5 95 TFMB 59.7 Comparative Example 6 97 m-Tb 39.8 Comparative Example 7 95 m-Tb 59.7 Comparative Example 8 7 53,4'-ODA 2 5 10.0

[0062] The abbreviations for the substances used in Table 1 above are as follows.

[0063] BPDA: Biphenyl tetracarboxylic dianhydride

[0064] PPD: 1,4-diaminobenzene

[0065] 3,4'-ODA: 3,4'-diaminodiphenyl ether

[0066] 4,4'-ODA: 4,4'-diaminodiphenyl ether

[0067] TFMB: 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl

[0068] m-Tb: 2,2'-dimethyl-4,4'-diaminobiphenyl

[0069] <Experimental Example: Evaluation of Physical Properties of Polyimide Film>

[0070] Experimental Example 1. Checking the Appearance of Polyimide Film

[0071] The appearance of the polyimide film was evaluated by visually observing the surface of the polyimide film manufactured in the examples and comparative examples to check whether bubbles were generated, and the results are shown in Table 2 according to the criteria below.

[0072] ○: No bubbles in 110 x 110mm glass substrate (excellent appearance)

[0073] ×: 3 or more bubbles in 110 x 110mm glass substrate (appearance defect)

[0074] Experimental Example 2. Adhesive Force Measurement

[0075] The adhesion of the polyimide films manufactured in Examples and Comparative Examples to polyimide-coated substrates was measured. The adhesion was measured using an INSTRON UTM 5546 model under conditions of 90° Peel mode and Cross Head Speed ​​of 50 mm / min after cutting the polyimide films on the a-Si substrate to 100 x 10 mm. The measurement results are shown in Table 2 below.

[0076] Experimental Example 3. Measurement of Coefficient of Thermal Expansion (CTE)

[0077] The coefficient of thermal expansion (CTE) was measured using a TA thermomechanical analyzer model Q400. The polyimide films manufactured in the examples and comparative examples were cut into 5 mm wide and 16 mm long pieces, and then, under a nitrogen atmosphere, a tension of 0.02 N was applied, the temperature was increased from room temperature to 470°C at a heating rate of 10°C / min, and then cooled again at a rate of 10°C / min, and the slope in the section from 100°C to 460°C was measured. The measurement results are shown in Table 2 below.

[0078] Experimental Example 4. Measurement of 1% thermal decomposition temperature (1% Td)

[0079] TA's thermogravimetric analysis Q50 model was used, and the polyimide films manufactured in the above examples and comparative examples were heated to 150°C at a rate of 10°C / min in a nitrogen atmosphere, and then maintained isothermally for 30 minutes to remove moisture. Thereafter, the temperature was increased to 600°C at a rate of 10°C / min, and the temperature at which a 1% weight loss occurred was measured, and the results are shown in Table 2 below.

[0080] Table 2 below shows the appearance, adhesive strength, coefficient of thermal expansion (CTE), and 1% thermal decomposition temperature (1% Td) values ​​of the polyimide films of Examples 1 to 3 and Comparative Examples 1 to 8.

[0081] ClassificationExternal Adhesion (N / cm)CTE (ppm / ℃)1% Td(℃)Example 1○1.413.7575Example 2○1.895.5577Example 3○1.908.8568Comparative Example 1×0.225.0569Comparative Example 2○0.2010.7571Comparative Example 3○0.2111.0571Comparative Example 4○1.275.7571Comparative Example 5○0.0110.0564Comparative Example 6×0.963.4566Comparative Example 7○0.966.8563Comparative Example 8○0.7810.8567

[0082] According to Table 2, it can be confirmed that the polyimide films of Examples 1 to 3 contain a small amount (3 to 20 mol%) of 3,4'-ODA, thereby having better adhesive strength than when the polyimide films do not contain a second diamine monomer (Comparative Example 1), contain a small amount of another diamine monomer (4,4'-ODA, TFMB, m-Tb) as the second diamine monomer (Comparative Examples 2 to 7), or contain an excessive amount (25 mol%) of 3,4'-ODA (Comparative Example 8).

[0083] In addition, it can be confirmed that the polyimide films of Examples 1 to 3 have excellent appearance (no bubbles) and heat resistance properties.

[0084] Specifically, when comparing Examples 1 and 2 and Comparative Examples 2 and 3, in which the same content of 3,4'-ODA and 4,4'-ODA was used, it was confirmed that the polyimide film including 3,4'-ODA had a lower coefficient of thermal expansion (CTE) and a higher 1% thermal decomposition temperature.

[0085] This is because the structure of 3,4'-ODA forms a polymer chain having a more linear structure than 4,4'-ODA, which has the effect of increasing the packing density of the polymer chain during heat curing. As the packing density increases, the polyimide film containing 3,4'-ODA has the effect of having higher substrate adhesion and superior heat resistance.

[0086] The specification omits detailed descriptions of matters that would be readily apparent and inferred by those skilled in the art. Furthermore, various modifications, other than the specific examples described herein, are possible without altering the technical spirit or essential configuration of the invention. Therefore, the present invention may be practiced in ways other than those specifically described and exemplified herein, as will be readily apparent to those skilled in the art.

Claims

1. Polyamic acid comprising an dianhydride monomer and a diamine monomer as polymerization units; and Contains environmentally friendly solvents; The above diamine monomer comprises a first diamine monomer and a second diamine monomer, The above first diamine monomer and the above second diamine monomer are different from each other, The second diamine monomer comprises 3,4'-diaminodiphenyl ether (3,4'-ODA), A polyimide precursor, wherein the diamine monomer comprises 80 to 99.9 mol% of the first diamine monomer and 0.01 to 20 mol% of the second diamine monomer, based on 100 mol% of the total diamine monomer.

2. In paragraph 1, A polyimide precursor, wherein the eco-friendly solvent comprises at least one selected from the group consisting of dimethylpropionamide (DMPA), 3-methoxy-N,N-dimethylpropanamide, tetramethyl urea (TMU), N-ethyl-2-pyrrolidone (NEP), and diethyl formamide (DEF).

3. In paragraph 1, The above dianhydride monomers are biphenyl tetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), bis(3,4-dicarboxyphenyl)sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-Phenylenebis(trimellitic monoester acid anhydride), p-Biphenylenebis(trimellitic monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-Bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-Bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-Bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-Bis〔(3,4-dicarboxy phenoxy)phenyl〕propane dianhydride (BPADA), 2,3,6,7-Naphthalene tetracarboxylic acid dianhydride, 1,4,5,8-Naphthalene tetracarboxylic A polyimide precursor comprising at least one selected from the group consisting of dianhydride and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride.

4. In paragraph 3, A polyimide precursor, wherein the above-mentioned dihydride monomer comprises biphenyl tetracarboxylic dianhydride (BPDA).

5. In paragraph 1, The above first diamine monomer is 1,4-diaminobenzene (PPD), 4,4'-diaminodiphenyl ether (4,4'-ODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2-bisaminophenoxyphenylpropane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-Tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-Diaminodiphenylmethane, 4,4'-Diaminodiphenylmethane, 2,2-Bis(3-aminophenyl)propane, 2,2-Bis(4-aminophenyl)propane, 2,2-Bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-Bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-Diaminodiphenylsulfoxide, 3,4'-Diaminodiphenylsulfoxide, 4,4'-Diaminodiphenylsulfoxide, 1,3-Bis(3-aminophenyl)benzene, 1,3-Bis(4-aminophenyl)benzene, 1,4-Bis(3-aminophenyl)benzene, 1,4-Bis(4-aminophenyl)benzene, 1,3-Bis(4-aminophenoxy)benzene (TPE-R), 1,4-Bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-Diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis〔2-(4-aminophenyl)isopropyl〕benzene, 1,4-bis〔2-(3-aminophenyl)isopropyl〕benzene, 1,4-bis〔2-(4-aminophenyl)isopropyl〕benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-Bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis〔3-(3-aminophenoxy)phenyl〕ether, bis〔3-(4-aminophenoxy)phenyl〕ether, bis〔4-(3-aminophenoxy)phenyl〕ether, bis〔4-(4-aminophenoxy)phenyl〕ether, bis〔3-(3-aminophenoxy)phenyl〕ketone, bis〔3-(4-aminophenoxy)phenyl〕ketone, bis〔4-(3-aminophenoxy)phenyl〕ketone, bis〔3-(3-aminophenoxy)phenyl〕sulfide, bis〔3-(4-aminophenoxy)phenyl〕sulfide, Bis〔4-(3-aminophenoxy)phenyl〕sulfide, bis〔4-(4-aminophenoxy)phenyl〕sulfide, bis〔3-(3-aminophenoxy)phenyl〕sulfone, bis〔3-(4-aminophenoxy)phenyl〕sulfone, bis〔4-(3-aminophenoxy)phenyl〕sulfone, bis〔4-(4-aminophenoxy)phenyl〕sulfone, bis〔3-(3-aminophenoxy)phenyl〕methane, bis〔3-(4-aminophenoxy)phenyl〕methane, bis〔4-(3-aminophenoxy)phenyl〕methane, bis〔4-(4-aminophenoxy)phenyl〕methane, 2,2-bis〔3-(3-aminophenoxy)phenyl〕propane, 2,2-bis〔3-(4-aminophenoxy)phenyl〕propane, 2,2-Bis〔4-(3-aminophenoxy)phenyl〕propane, 2,2-bis〔3-(3-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane, 2,2-bis〔3-(4-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane, 2,A polyimide precursor comprising at least one selected from the group consisting of 2-bis〔4-(3-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane and 2,2-bis〔4-(4-aminophenoxy)phenyl〕-1,1,1,3,3,3-hexafluoropropane.

6. In paragraph 5, A polyimide precursor, wherein the first diamine monomer comprises 1,4-diaminobenzene (PPD).

7. In paragraph 1, The above dianhydride monomer is biphenyl tetracarboxylic dianhydride (BPDA), The above first diamine monomer is 1,4-diaminobenzene (PPD), A polyimide precursor, wherein the second diamine monomer is 3,4'-diaminodiphenyl ether (3,4'-ODA).

8. A step of manufacturing a polyamic acid by polymerizing an dianhydride monomer and a diamine monomer in an eco-friendly solvent, thereby manufacturing a polyimide precursor including a polyamic acid and an eco-friendly solvent; The above diamine monomer comprises a first diamine monomer and a second diamine monomer, The above first diamine monomer and the above second diamine monomer are different from each other, The second diamine monomer comprises 3,4'-diaminodiphenyl ether (3,4'-ODA), A method for producing a polyimide precursor, wherein the diamine monomer comprises 80 to 99.9 mol% of the first diamine monomer and 0.01 to 20 mol% of the second diamine monomer based on 100 mol% of the total diamine monomer.

9. In paragraph 8, The step of manufacturing the above polyimide precursor (a) a step of preparing a solution by mixing an dianhydride monomer in an eco-friendly solvent; and (b) a step of adding a first diamine monomer to the solution, and then adding a second diamine monomer, mixing them, and reacting them to produce a solution containing polyamic acid; A method for producing a polyimide precursor, comprising:

10. In paragraph 9, A method for producing a polyimide precursor, wherein the reaction of step (b) is performed at room temperature (20 to 25°C) for 4 to 24 hours.

11. A polyimide film comprising a cured product of a polyimide precursor according to Article 1.

12. In paragraph 11, A polyimide film having a thickness of 1 to 100 μm.

13. In paragraph 11, A polyimide film having an adhesive strength of 1.0 to 2.5 N / cm to an a-Si substrate.

14. In paragraph 11, A polyimide film having a coefficient of thermal expansion (CTE) of 1 to 10 ppm / ℃.

15. In paragraph 11, A polyimide film having a 1% thermal decomposition temperature (Td) of 300 to 600°C.