Polyamic acid composition and polyimide prepared from same

Abstract

The present disclosure provides a polyamic acid composition comprising: a polyamic acid including a dianhydride monomer and a diamine monomer as polymerization units; and an additive containing imidazole, in which the amount of the additive is 0.01 to 5 parts by weight based on 100 parts by weight of the polyamic acid.

Description

Technical Field

[0001] This disclosure relates to a polyamic acid composition and a polyimide prepared therefrom. More specifically, this disclosure relates to a polyamic acid composition that, by comprising an additive containing imidazole, enables the preparation of a polyimide with excellent mechanical properties. Background Technology

[0002] Generally, polyimide (PI) is a polymer material based on an imine ring with excellent chemical stability and a rigid aromatic backbone. It possesses the highest heat resistance, chemical resistance, electrical insulation, and weather resistance among organic materials and can be prepared in various forms such as films, fibers, and membranes. Due to these properties, polyimide is widely used as an advanced material and insulating coating in many fields, such as electronics, semiconductors, displays, automobiles, and aerospace materials.

[0003] Recently, as various electronic devices have become thinner, lighter, and smaller, lightweight and highly flexible polyimide films have been widely studied as display substrates that can replace traditional insulating materials in circuit boards or glass substrates in displays.

[0004] Polyimide can be prepared by the following steps: dissolving an acid dianhydride with two anhydride groups in a solvent and a diamine with two amino groups in a solvent to synthesize a polyimide precursor called polyamic acid (PAA). The precursor is then coated and dried, and heat-treated at a temperature of about 350°C to induce imidization.

[0005] Meanwhile, traditional polyamic acid compositions have problems because their structure is like a string of beads. Although they are electrospinnable during electrospinning, their mechanical properties are poor.

[0006] Therefore, it is necessary to develop a polyimide with improved electrospinnability, relatively high molecular weight and excellent mechanical properties. Summary of the Invention

[0007] [Technical Issues] The purpose of this disclosure is to provide a polyimide with relatively high molecular weight and excellent mechanical properties, and a polyamic acid composition capable of preparing such a polyimide.

[0008] Furthermore, another object of this disclosure is to provide a polyamic acid composition that has improved electrospinnability without the need for chemical crosslinking.

[0009] Furthermore, another object of this disclosure is to provide a polyamic acid composition capable of preparing a polyimide that can be used as a secondary battery separator, membrane, film, or coating material.

[0010] [Technical Solution] Various modifications and implementation schemes can be made in this disclosure, and specific implementation schemes are illustrated and described in detail with reference to the accompanying drawings. However, it should be understood that this is not intended to limit this disclosure to the specific implementation schemes, but rather to include all modifications, equivalents, and substitutions within the spirit and scope of this disclosure.

[0011] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, singular expressions should include plural expressions. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, quantities, steps, operations, components, parts or combinations thereof described in this specification, and should not be construed as excluding the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts or combinations thereof.

[0012] When quantities, concentrations, or other values ​​or parameters in this document are given in the form of ranges, preferred ranges, or lists of desired upper and lower limits, they should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value and any lower or preferred value, regardless of whether the range is disclosed individually.

[0013] Unless otherwise stated, when numerical ranges are described herein, they are intended to indicate the endpoints of the range and the scope of protection of the original invention within that range, and are not limited to the specific values ​​described when the range is defined.

[0014] As used herein, “dianhydride” is intended to include its precursors or derivatives, also known as “dianhydride acid,” “dianhydride,” or “acid dianhydride.” Technically, these products may not be dianhydrides, but they can still react with diamines to form polyamic acids, which can be converted back into polyimides.

[0015] As used herein, “diamine” is intended to include its precursors or derivatives, which may not technically be diamines but can still react with dianhydrides to form polyamic acids, which can then be converted back into polyimides.

[0016] 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 related to this disclosure. It should be further understood that terms commonly defined in dictionaries should be interpreted according to their meaning as understood in the relevant technical field and in the context of this disclosure, rather than according to idealized or overly formalized meanings, unless otherwise expressly defined herein. Specific details of implementing this disclosure will be described below.

[0017] This disclosure relates to a polyamic acid composition and a polyimide prepared therefrom.

[0018] Specifically, this disclosure provides a polyamic acid composition comprising: polyamic acid including dianhydride monomer and diamine monomer as polymerization units; and an additive containing imidazole, wherein the amount of the additive is 0.01 to 5 parts by weight based on 100 parts by weight of polyamic acid.

[0019] In this article, imidazole is the imidazole represented by the following structural formula 1: [Structure 1] .

[0020] In this document, the polyamic acid composition may contain the following additives in amounts: 0.01 to 5 parts by weight, preferably 0.01 to 3 parts by weight, 0.01 to 2.5 parts by weight, 0.01 to 2 parts by weight, 0.01 to 1.5 parts by weight, 0.01 to 1 part by weight, 0.01 to 0.5 parts by weight, 0.01 to 0.15 parts by weight, 0.1 to 5 parts by weight, 0.1 to 3 parts by weight, 0.1 to 2.5 parts by weight, 0.1 to 2 ... 1.5 parts by weight, 0.1 to 1 part by weight, 0.1 to 0.5 parts by weight, 0.15 to 5 parts by weight, 0.15 to 3 parts by weight, 0.15 to 2.5 parts by weight, 0.15 to 2 parts by weight, 0.15 to 1.5 parts by weight, 0.15 to 1 part by weight, 0.1 to 0.5 parts by weight, 0.2 to 5 parts by weight, 0.2 to 3 parts by weight, 0.2 to 2.5 parts by weight, 0.2 to 2 parts by weight, 0.2 to 1.5 parts by weight, 0.2 to 1 part by weight Parts by weight, 0.1 to 0.5 parts by weight, 0.3 to 5 parts by weight, 0.3 to 3 parts by weight, 0.3 to 2.5 parts by weight, 0.3 to 2 parts by weight, 0.3 to 1.5 parts by weight, 0.3 to 1 part by weight, 0.1 to 0.5 parts by weight, 0.4 to 5 parts by weight, 0.4 to 3 parts by weight, 0.4 to 2.5 parts by weight, 0.4 to 2 parts by weight, 0.4 to 1.5 parts by weight, 0.4 to 1 part by weight, 0.4 to 0.5 parts by weight, 0.5 to 5 parts by weight The amounts are: parts by weight, 0.5 to 3 parts by weight, 0.5 to 2.5 parts by weight, 0.5 to 2 parts by weight, 0.5 to 1.5 parts by weight, 0.5 to 1 part by weight, 1 to 5 parts by weight, 1 to 3 parts by weight, 1 to 2.5 parts by weight, 1 to 2 parts by weight, 1 to 1.5 parts by weight or 3 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, 0.2 to 2.5 parts by weight, 0.3 to 2 parts by weight, 0.4 to 1.5 parts by weight, and most preferably 0.5 to 1 part by weight.

[0021] When the amount of additive is less than 0.01 parts by weight, it is not preferred because the mechanical properties deteriorate; and when the amount of additive is greater than 5 parts by weight, the viscosity and molecular weight decrease under room temperature or frozen storage conditions, resulting in storage difficulties and poor electrospinning properties, which is also not preferred.

[0022] The imidazole contained in this disclosure is not used as an imidization catalyst, but as an additive to improve the electrospinnability of polyamic acid. Even based on 100 parts by weight of polyamic acid, a small amount of additive, only 0.01 to 5 parts by weight, can significantly improve electrospinning stability, and the polyimide films prepared therefrom exhibit excellent mechanical properties.

[0023] Dianone monomers may include at least one selected from the following: biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxophthalic dianhydride (ODPA), diphenyl sulfone-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'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(triphenyltriacrylic acid monoester anhydride), p-biphenylenebis(triphenyltriacrylic acid monoester anhydride), meta-triacrylic acid... The dianhydride comprises biphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride, and preferably may contain at least one selected from biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA), and more preferably biphenyltetracarboxylic dianhydride (BPDA).

[0024] Specifically, based on a total of 100 mol% of dianhydride monomers, the dianhydride monomers may contain 90 mol% or more of biphenyltetracarboxylic acid dianhydride (BPDA). By containing 90 mol% or more of biphenyltetracarboxylic acid dianhydride, polyimides with excellent desired mechanical properties can be prepared.

[0025] Simultaneously, the dianhydride monomer may comprise biphenyl tetracarboxylic dianhydride (BPDA), and may further comprise at least one selected from the following: pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxyphthalic dianhydride (ODPA), diphenyl sulfone-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'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane The following are dianhydrides: p-phenylene bis(triphenyltriglyceride monoester anhydride), p-biphenylene bis(triphenyltriglyceride monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride. Preferably, it may further include pyromellitic dianhydride (PMDA).

[0026] The diamine monomer may comprise at least one selected from the following: 4,4'-diaminodiphenyl ether (4,4'-ODA), 1,4-diaminobenzene (PPD), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-bitoluidine), 2,2-diaminophenoxyphenylpropane (BAPP), m-phenylenediamine, 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'-diaminobenzoylaniline, 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'-diaminodibenzophenone, 4,4'-diaminodibenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-di... Aminodiphenylmethane, 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'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 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'-bis(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,4-bis(4-aminophenyl sulfone)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]one, bis[4-(3-aminophenoxy)phenyl]one, bis[4-(4-aminophenoxy)phenyl]one, 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]propane The mixture comprises 1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and preferably may contain at least one selected from 1,4-diaminobenzene (PPD) and 4,4'-diaminodiphenyl ether (ODA).

[0027] Based on a total of 100 mol% of diamine monomers, the diamine monomers may contain 50 mol% or more of 1,4-diaminobenzene (PPD), specifically 50 to 100 mol%, 55 to 90 mol%, 60 to 85 mol%, 65 to 80 mol%, or 68 to 75 mol%. When the amount of 1,4-diaminobenzene (PPD) is 100 mol%, the amount of 4,4′-diaminodiphenyl ether (ODA) may be 0 mol.

[0028] Based on a total of 100 mol% of diamine monomers, the diamine monomers may contain 50 mol% or less of 4,4′-diaminodiphenyl ether (ODA), specifically 0 to 50 mol%, 10 to 45 mol%, 15 to 40 mol%, 20 to 35 mol%, or 25 to 32 mol%. When the amount of 4,4′-diaminodiphenyl ether (ODA) is 0 mol%, the amount of 1,4-diaminobenzene (PPD) may be 100 mol.

[0029] In other words, based on a total of 100 mol% diamine monomers, the sum of the amounts of 1,4-diaminobenzene (PPD) and 4,4′-diaminodiphenyl ether (ODA) can be 100 mol.

[0030] Polyimides with excellent desired mechanical properties can be prepared by using 50 mol% or more of 1,4-diaminobenzene (PPD) (50 mol% or less of 4,4'-diaminodiphenyl ether (ODA)) as a diamine monomer.

[0031] In one embodiment, the polyamic acid may comprise biphenyl tetracarboxylic dianhydride (BPDA), 1,4-diaminobenzene (PPD), and 4,4′-diaminodiphenyl ether (ODA) as polymerization units.

[0032] In one embodiment, the polyamic acid may comprise biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), 1,4-diaminobenzene (PPD), and 4,4′-diaminodiphenyl ether (ODA) as polymerization units.

[0033] The molar ratio of dianhydride monomer to diamine monomer can be 6:4 to 4:6, preferably 5.5:4.5 to 4.5:6.5, and more preferably 5:5.

[0034] The polyamic acid may contain 90 to 110 mol%, preferably 95 to 105 mol%, more preferably 98 to 102 mol%, and even more preferably 99 to 101 mol% of a diamine monomer.

[0035] The polyamic acid may contain 90 to 110 mol%, preferably 95 to 105 mol%, more preferably 98 to 102 mol%, and even more preferably 100 mol% of dianhydride monomer.

[0036] Based on 100 mol% of diamine monomer, polyamic acid may contain 95 to 105 mol% of dianhydride monomer. For example, the lower limit of the amount of dianhydride monomer 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.

[0037] The polyamic acid composition may further contain a solvent.

[0038] The solvent may contain at least one selected from the following: N,N′-dimethylacetamide (DMAc), N,N'-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), diethylacetamide (DEAc), N-ethyl-2-pyrrolidone (NEP), N,N′-diethylformamide (DEF), dimethylpropionamide (DMPA), and γ-butyrolactone (GBL). Preferably, N,N′-dimethylacetamide (DMAc) may be used.

[0039] The viscosity of the polyamic acid composition can be from 5,000 to 300,000 cP.

[0040] The weight-average molecular weight (Mw) of the polyamic acid composition is preferably from 10,000 to 500,000 (g / mol), more preferably from 100,000 to 400,000 (g / mol), 150,000 to 350,000 (g / mol), 180,000 to 320,000 (g / mol), and even more preferably from 200,000 to 300,000 (g / mol). A molecular weight of 10,000 to 500,000 (g / mol) is preferred because it facilitates electrospinning and improves process stability. It is confirmed that the molecular weight of the polyamic acid composition disclosed herein is higher than that of conventional polyamic acid compositions without imidazole.

[0041] In one embodiment, the modulus of the cured polyamic acid composition can be 4 GPa or higher. For example, the lower limit of the modulus can be 4.5 GPa or higher, 4.7 GPa or higher, or 5 GPa or higher. Furthermore, there is no particular limitation on the upper limit of the modulus, but it can be 18 GPa or lower, 17 GPa or lower, 16 GPa or lower, or 15 GPa or lower. The modulus can be determined by preparing a sample with a length of 220 mm and a width of 15 mm, measuring the modulus using an Instron 5564 Universal Testing Machine (UTM) from INSTRON at a rate of 10 mm / min, and calculating the average value of 10 samples.

[0042] In one embodiment, the tensile strength of the cured polyamic acid composition can be 180 MPa or higher. For example, the lower limit of the tensile strength can be 190 MPa or higher, 195 MPa or higher, 200 MPa or higher, 205 MPa or higher, 210 MPa or higher, 215 MPa or higher, or 220 MPa or higher. Furthermore, there is no particular limitation on the upper limit of the tensile strength, but it can be 400 MPa or lower. The tensile strength can be determined by preparing samples with a length of 220 mm and a width of 15 mm, measuring the tensile strength using an INSTRON Instron 5564 UTM according to ASTM D-882, at a gripping interval of 50 mm and a rate of 10 mm / min, and calculating the average value of 10 samples.

[0043] In one embodiment, the elongation of the cured polyamic acid composition can be 9% or higher. For example, the lower limit of elongation can be 10% or higher, 11% or higher, 12% or higher, 12.5% ​​or higher, 12.8% or higher, or 13% or higher. Furthermore, there is no particular limitation on the upper limit of elongation, but it can be 80% or lower. In one embodiment, the elongation can be determined by preparing a sample with a length of 220 mm and a width of 15 mm, and measuring the elongation at a rate of 10 mm / min according to ASTM D-882 using an Instron 5564 UTM from INSTRON.

[0044] Another embodiment of this disclosure provides a polyimide comprising a cured product of a polyamic acid composition.

[0045] Another embodiment of this disclosure provides a polyimide film prepared using a polyamic acid composition.

[0046] The thickness of the polyimide film can be appropriately selected considering the application, operating environment, and physical properties of the polyimide film. For example, the thickness of the polyimide film can be 1 to 100 µm, 15 to 70 µm, 25 to 50 µm, or 30 to 45 µm, but is not limited to these.

[0047] [Beneficial Effects] The polyamic acid compositions according to this disclosure can provide polyimides with relatively high molecular weight and excellent mechanical properties.

[0048] Furthermore, the polyamic acid composition according to this disclosure can improve electrospinnability (processability) by using an additive containing imidazole without chemical crosslinking.

[0049] Furthermore, the polyamic acid compositions according to this disclosure and the polyimides prepared therefrom can be used in secondary battery separators, membranes, films, or coating materials. Attached Figure Description

[0050] Figure 1 These are scanning electron microscope (SEM) images of the polyamic acid composition prepared according to Examples 1-1 after electrospinning.

[0051] Figure 2 These are scanning electron microscope (SEM) images of the polyamic acid compositions prepared according to Examples 1-2 after electrospinning.

[0052] Figure 3 The images are scanning electron microscope (SEM) images of the polyamic acid composition prepared according to Comparative Example 1-1 after electrospinning.

[0053] Figure 4 Images are shown of polyamic acid compositions prepared according to Examples 1-2, Examples 1-5 and Comparative Examples 1-6 after storage in a freezer (-15°C). Detailed Implementation

[0054] Examples are provided to facilitate understanding of the invention. The following examples are provided merely for a more illustrative purpose, and the scope of the invention is not limited to these examples.

[0055] <Example 1. Polyamic Acid Composition> Example 1-1 Under a nitrogen atmosphere at 35°C, 70 mol% of 1,4-diaminobenzene (PPD) was added to and dissolved in an organic solvent of N,N′-dimethylacetamide (DMAc). Then, 100 mol% of biphenyltetracarboxylic acid dianhydride (BPDA) was added, and the mixture was stirred for 3 hours. Subsequently, 30 mol% of 4,4′-diaminodiphenyl ether (ODA) was added to obtain polyamic acid. Imidazole (1,500 ppm, equivalent to 0.15 parts by weight per 100 parts of the obtained polyamic acid) was mixed with the obtained polyamic acid as an additive, and the mixture was stirred for 1 hour to prepare a polyamic acid composition.

[0056] Examples 1-2 to 1-9 and Comparative Examples 1-1 to 1-6 Each polyamic acid composition was prepared using the same method as in Examples 1-1, except that, as shown in Table 1, the types and amounts of dianhydride monomers and diamine monomers used, as well as the types and amounts of additives used, were varied.

[0057] According to Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-6, the types and amounts of monomers / additives used in preparing the polyamic acid compositions are shown in Table 1 below.

[0058] [Table 1]

[0059] The abbreviations in Table 1 are as follows: BPDA: Biphenyltetracarboxylic acid dianhydride PMDA: Pyromellitic dianhydride PPD: p-phenylene diamine ODA: 4,4′-Diaminodiphenyl ether.

[0060] <Example 2: Polyimide Film> Example 2-1 Using spin coating, the polyamic acid composition prepared according to Examples 1-1 was coated onto a glass substrate to a thickness of 20 µm, and the temperature was gradually increased to 90 °C, 170 °C, 200 °C and 400 °C to obtain a polyimide film.

[0061] Examples 2-2 to 2-9 and Comparative Examples 2-1 to 2-6 Polyimide films were prepared using the same method as in Examples 2-1, except that the polyamic acid composition was changed to the polyamic acid compositions of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-6, respectively.

[0062] <Experimental Example> Experimental Example 1. Confirmation of the molecular weight of the polyamic acid composition To confirm the change in molecular weight with respect to the amount of imidazole, the weight-average molecular weight (Mw) of the polyamic acid compositions prepared according to Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-6 is shown in Table 2 below.

[0063] Specifically, gel permeation chromatography (GPC) analysis was performed to confirm the weight-average molecular weight (Mw) of the polyamic acid compositions prepared according to Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-6. Analysis was performed using an Agilent 1260 Infinity II GPC / SEC system and an Agilent PLgel hybrid-C column (300 × 7.5 mm, 5 mm). N-methyl-2-pyrrolidone (NMP) was used as the mobile phase at a flow rate of 1.0 mL / min and a column temperature of 50 °C. A differential refractive index detector was used as the detector. The sample was dissolved in NMP at a concentration of 2 mg / mL, filtered through a 0.20 μm PTFE filter, and then injected. Molecular weight calibration was performed using monodisperse polystyrene standards.

[0064] [Table 2]

[0065] According to Table 2, it was confirmed that in the same polyamic acid composition (BPDA 100mol%, PPD 70mol%, ODA 30mol%), the molecular weight of the polyamic acid composition also increased with the increase of imidazole content.

[0066] Experimental Example 2. Mechanical Performance Evaluation To compare the mechanical properties (modulus, tensile strength, and elongation) after the addition of imidazole, the physical properties of polyimide films (Examples 2-1 and 2-2, Comparative Examples 2-1, 2-4, and 2-5) prepared from polyamic acid compositions (Examples 1-1 and 1-2, Comparative Examples 1-1, 1-4, and 1-5) having the same amounts of dianhydride monomer and diamine monomer were confirmed by the following methods.

[0067] (1) Modulus For the polyimide films in Examples 2-1 and 2-2 and Comparative Examples 2-1, 2-4, and 2-5, polyimide film samples with a length of 220 mm and a width of 15 mm were prepared, and the modulus was measured using an Instron 5564 universal testing machine (UTM) from INSTRON at a rate of 10 mm / min. The average value of the 10 samples was calculated and is shown in Table 3 below.

[0068] (2) Tensile strength For the polyimide films in Examples 2-1 and 2-2 and Comparative Examples 2-1, 2-4, and 2-5, polyimide film samples with a length of 220 mm and a width of 15 mm were prepared. Tensile strength was determined using an Instron 5564 Universal Testing Machine (UTM) from INSTRON, according to ASTM D-882, at a gripping interval of 50 mm and a rate of 10 mm / min. The average values ​​for the 10 samples were calculated and are shown in Table 3 below.

[0069] (3) Elongation For the polyimide films in Examples 2-1 and 2-2 and Comparative Examples 2-1, 2-4, and 2-5, polyimide film samples with a length of 220 mm and a width of 15 mm were prepared, and the elongation was measured at a rate of 10 mm / min using an Instron 5564 UTM from INSTRON according to ASTM D-882. The average values ​​of the samples were calculated and are shown in Table 3 below.

[0070] [Table 3]

[0071] According to Table 3, it can be confirmed that when imidazole is used as an additive (Examples 2-1 and 2-2), the polyimide film prepared from a polyamic acid composition having 100 mol% BPDA, 70 mol% PPD, and 30 mol% ODA has a modulus of 6 GPa or higher, a tensile strength of 230 MPa or higher, and an elongation of 17% or higher. On the other hand, it can be confirmed that when no additive is used (Comparative Example 2-1) or when 2-phenylimidazole and 1,2-dimethylimidazole are used as additives (Comparative Examples 2-4 and 2-5), the mechanical properties are lower than those when imidazole is used as an additive (Examples 2-1 and 2-2).

[0072] Experimental Example 3. Processability Assessment (1) Confirmation of electrospinning capability Based on images obtained by scanning electron microscopy (SEM) after electrospinning, the electrospinnability (processability) of the polyamic acid compositions according to Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-6 was evaluated, and the results are shown in Table 4 below.

[0073] Figure 1 These are SEM images of the polyamic acid composition prepared according to Example 1-1 after electrospinning. Figure 2 These are SEM images of the polyamic acid compositions prepared according to Examples 1-2 after electrospinning, and Figure 3 The image shows a SEM image of the polyamic acid composition prepared according to Comparative Example 1-1 after electrospinning.

[0074] according to Figure 1 It was confirmed that the polyamic acid composition prepared according to Examples 1-1 contained a small amount (1,500 ppm) of imidazole, thus slightly improving electrospinning properties, but making it difficult to form a web structure. Therefore, as Figure 1 As shown, when electrospinnability is improved but it is difficult to form a web structure, it is indicated by ○ in Table 4 below.

[0075] At the same time, Figure 2 It was confirmed that the polyamic acid compositions prepared according to Examples 1-2 contained 5,000 ppm imidazole, thus further improving electrospinnability. Therefore, as... Figure 2 As shown, when the electrospinnability is improved and a network structure can be formed, it is indicated by ◎ in Table 4 below.

[0076] On the other hand, Figure 3 It was confirmed that Comparative Example 1-1, which did not contain imidazole in the same diamine monomer and dianhydride monomer composition, had many bead-like structures. Therefore, as... Figure 3 As shown, when electrospinnability is not improved, resulting in numerous beaded structures, this is indicated by △ in Table 4 below. The presence of numerous beaded structures is undesirable due to poor mechanical properties.

[0077] [Table 4]

[0078] In Table 4, the meaning of each symbol is as follows: ◎This indicates that the electrospinning property is improved, enabling the formation of a network structure. ○ The indicator shows that electrospinning properties are improved, but it is still difficult to form a network structure. △ indicates that due to the lack of improved electrospinning properties, numerous bead-like structures are formed. The X indicator indicates that electrospinning cannot be performed.

[0079] According to Table 4, it can be confirmed that the polyamic acid composition of this disclosure exhibits improved electrospinnability by containing imidazole, especially when the amount of imidazole is 0.5 parts by weight (5,000 ppm) or 1 part by weight (10,000 ppm) per 100 parts by weight of polyamic acid, the electrospinnability is improved to the extent that a network structure can be formed.

[0080] (2) Confirmation of frozen storage Figure 4 Images of Examples 1-2, 1-5, and Comparative Examples 1-6 after storage in a freezer (-15°C) are shown.

[0081] according to Figure 4 It was observed that Examples 1-2 containing 5,000 ppm imidazole showed no change over time after being stored in a freezer for 7 days, while Examples 1-5 containing 50,000 ppm imidazole did not show any haze within 2 days of frozen storage, but haze appeared after 2 days or longer.

[0082] Meanwhile, it was confirmed that Comparative Examples 1-6, containing 51,000 ppm imidazole, formed gels after 6 hours.

[0083] These results confirm that stable transparency can be maintained for two days or longer when the imidazole concentration is 50,000 ppm or less, but when the concentration exceeds this range, fogging and gel formation occur within just 6 hours, rapidly reducing frozen storage performance. Therefore, it is confirmed that even a minute difference of approximately 1,000 ppm can result in significant differences in stability.

[0084] In other words, the polyamic acid composition according to this disclosure includes an appropriate amount of imidazole-containing additives, so that it does not change over time even after frozen storage, thereby maintaining good electrospinnability (processability).

[0085] In this specification, detailed descriptions of content that can be fully understood and inferred by those skilled in the art have been omitted. Besides the specific exemplary embodiments described herein, various changes and modifications can be made without altering the technical spirit or basic configuration of this disclosure. Therefore, this disclosure can also be implemented in ways different from those specifically described and illustrated herein, as will be understood by those skilled in the art.

Claims

1. A polyamic acid composition comprising: Polyamic acid, comprising dianhydride monomers and diamine monomers as polymerization units; and Additives containing imidazole, The amount of the additive is 0.01 to 5 parts by weight, based on 100 parts by weight of the polyamic acid.

2. The polyamic acid composition according to claim 1, wherein the polyamic acid composition comprises 0.1 to 3 parts by weight of the additive, based on 100 parts by weight of the polyamic acid.

3. The polyamic acid composition according to claim 2, wherein the polyamic acid composition contains 0.5 to 1 part by weight of the additive, based on 100 parts by weight of the polyamic acid.

4. The polyamic acid composition according to claim 1, wherein the dianhydride monomer comprises at least one selected from the group consisting of: Biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), diphenyl sulfone-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'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylene bis(triphenylene oxide monophosphate) The anhydrides include: terphenyl bis(triphenyltriacrylic acid monoester anhydride), terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride.

5. The polyamic acid composition according to claim 1, wherein the dianhydride monomer comprises 90 mol% or more of biphenyltetracarboxylic acid dianhydride (BPDA) based on a total of 100 mol% of the dianhydride monomer.

6. The polyamic acid composition according to claim 1, wherein the diamine monomer comprises at least one selected from the group consisting of: 4,4'-Diaminodiphenyl ether (4,4'-ODA), 1,4-Diaminobenzene (PPD), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-bitoluidine), 2,2-diaminophenoxyphenylpropane (BAPP), m-phenylenediamine, 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'-diaminobenzoylaniline, 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'-diaminodiphenyl ketone, 4,4'-diaminodiphenyl ketone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzphenone, 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'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 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'-bis(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,3-bis(4-aminophenyl sulfone)benzene, 1,4-bis(4-aminophenyl sulfone)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]one, bis[3- [4-aminophenoxy]phenyl]one, bis[4-(3-aminophenoxy)phenyl]one, bis[4-(4-aminophenoxy)phenyl]one, 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-(4-aminophenoxy)phenyl]sulfone, bis[4-(3 ... -(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, 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, [3-(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, 2,2-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.

7. The polyamic acid composition according to claim 1, wherein the diamine monomer comprises 50 mol% or more of 1,4-diaminobenzene (PPD) based on a total of 100 mol% of the diamine monomer.

8. The polyamic acid composition according to claim 1, wherein the diamine monomer comprises 50 mol% or less of 4,4′-diaminodiphenyl ether (ODA) based on a total of 100 mol% of the diamine monomer.

9. The polyamic acid composition according to claim 1, wherein the modulus of the polyamic acid composition after curing is 4 GPa or higher.

10. The polyamic acid composition according to claim 1, wherein the tensile strength of the polyamic acid composition after curing is 180 MPa or higher.

11. The polyamic acid composition according to claim 1, wherein the elongation of the polyamic acid composition after curing is 9% or higher.

12. A polyimide comprising a cured product of the polyamic acid composition according to any one of claims 1 to 11.

13. A polyimide film prepared by using a polyamic acid composition according to any one of claims 1 to 11.

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