Methylenedianiline-based polyimide film and manufacturing method thereof

Abstract

The present invention provides a polyimide film comprising, as polymeric units, dianhydride monomers comprising pyromellitic dianhydride (PMDA), and diamine monomers comprising 4,4'-methylenedianiline (MDA), meta-phenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA), and para-phenylenediamine (PPD), the tensile strength and percent elongation of the polyimide film being 180 MPa or greater and 90% or greater, respectively.

Description

Methylenedianiline-based polyimide film and method for manufacturing the same

[0001] The present invention relates to a methylenedianiline-based polyimide film and a method for manufacturing the same. More specifically, it relates to a polyimide film with excellent mechanical properties and a method for manufacturing the same by including a high content of methylenedianiline (4,4'-Methylenedianiline, MDA).

[0002] Polyimide (PI) is a polymer material based on imide rings with excellent chemical stability and a rigid aromatic main chain, possessing the highest levels of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials. As an insoluble and infusible ultra-high heat-resistant resin, polyimide resin is used in various forms such as films, resins, molded parts, adhesives, and insulators in the electrical, electronic, automotive, and aerospace industries due to its high glass transition temperature, excellent heat oxidation resistance, heat resistance, radiation resistance, low-temperature properties, chemical resistance, and electrical properties. In particular, the battery (especially secondary battery) market is experiencing rapid growth following the recent expansion of the electric vehicle market.

[0003] In manufacturing a secondary battery, the outer surface of an electrode assembly is wrapped with tape to secure the electrode assembly (sometimes referred to as a 'jelly roll') so that it does not unravel, so that the electrode assembly is housed within a cylindrical or pouch-type battery case. That is, tape is applied to wrap the outer surface of an electrode assembly in which a positive plate, a separator, and a negative plate are stacked in sequence, and such tape is generally referred to as a finishing tape.

[0004] Polyimide films with excellent heat resistance can be used as resins for such finishing tapes. Generally, polyimide (PI) films are formed by film-forming polyimide resin. Polyimide resin refers to a high-heat-resistant resin produced by solution polymerizing aromatic dianhydrides with aromatic diamines or aromatic diisocyanates to produce polyamic acid derivatives, and then converting them into imides by ring-closing dehydration at high temperatures.

[0005] Conventional polyimide resins for finishing tapes mainly used 4,4'-diaminodiphenyl ether (ODA) as an aromatic diamine, but when a large amount of ODA was used, the cost increased, leading to reduced economic feasibility, and there were problems such as reduced physical properties like tensile strength or elastic modulus due to the flexible structure of ODA.

[0006] Accordingly, there is a need to develop polyimide films with improved physical properties, such as tensile strength, while maintaining elongation and reducing the ODA content.

[0007] The present invention aims to provide a polyimide film and a method for manufacturing the same, which reduces costs by using methylenedianiline (4,4'-Methylenedianiline, MDA) and improves mechanical properties (elongation and tensile strength) by controlling the structure of the polyimide through an optimal monomer combination.

[0008] In addition, the present invention aims to provide a polyimide film having excellent mechanical properties (elongation and tensile strength) as a block copolymer comprising two or more blocks, and a method for manufacturing the same.

[0009] In addition, the present invention aims to provide a molded article comprising a polyimide film.

[0010] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be illustrated and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0011] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0012] Where in this specification, when a quantity, concentration, or other value or parameter is given as an enumeration of a range, a preferred range, a preferred upper limit, and a preferred lower limit, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value are specifically disclosed, regardless of whether the range is disclosed separately.

[0013] Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, the range and the scope of the invention within that range are not intended to be limited to the specific value mentioned when defining the range.

[0014] In this specification, "dianhydride" is intended to include its precursor or derivative, and is also referred to as "dianhydride," "dianhydride," or "acid dianhydride." Although these may not technically be dianhydrides, they will nevertheless react with a diamine to form a polyamic acid, which can then be converted into a polyimide.

[0015] In this specification, "diamine" is intended to include its precursors or derivatives, which may not technically be diamines but nevertheless will react with dianhydrides to form polyamic acids, which can then be converted into polyimides.

[0016] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application. Specific details for the implementation of the above invention are described below.

[0017] The present invention relates to a polyimide film with excellent mechanical properties (elongation and tensile strength) and a method for manufacturing the same by introducing methylenedianiline (4,4'-Methylenedianiline, MDA).

[0018] polyimide film

[0019] Specifically, the present invention provides a polyimide film comprising a dianhydride monomer including pyromellitic dianhydride (PMDA) and a diamine monomer including 4,4'-methylenedianiline (MDA), metaphenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA), and paraphenylenediamine (PPD) as polymerization units, having a tensile strength of 180 MPa or more and an elongation of 90% or more.

[0020] The above tensile strength is measured using an INSTRON Instron 5564 UTM device, and preferably, the lower limit may be 181 MPa or higher, 182 MPa or higher, 183 MPa or higher, 184 MPa or higher, or 185 MPa or higher, and the upper limit is not specifically limited but may be 400 MPa or lower.

[0021] The above elongation is measured using an INSTRON Instron 5564 UTM device, and preferably, the lower limit may be 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, or 100%, and the upper limit is not specifically limited but may be 300% or less.

[0022] In addition, the content of the 4,4'-methylenedianiline (MDA) in the total diamine monomer may be 60 mol% or more and less than 100 mol%, and preferably the upper limit may be 99 mol% or less, 95 mol% or less, 90 mol% or less, 85 mol% or less, 83 mol% or less, 80 mol% or less, 78 mol% or less, 75 mol% or less, 74 mol% or less, 73 mol% or less, 72 mol% or less, 71 mol% or less, or 70 mol% or less.

[0023] If the MDA content is less than 60 mol%, it is not desirable because the cost reduction effect is negligible, and if it is 100 mol%, it is not desirable because the elongation is reduced compared to the oxygen (O) bond of ODA with a similar structure, since the component connecting the ring is carbon (C).

[0024] In addition, the content of metaphenylenediamine (MPD) among the total diamine monomers may be 5 mol% to 30 mol%, preferably the lower limit may be 6 mol% or more, 7 mol% or more, 8 mol% or more, 9 mol% or more, or 10 mol% or more, and the upper limit may be 29 mol% or less, 28 mol% or less, 27 mol% or less, 26 mol% or less, 25 mol% or less, 24 mol% or less, 23 mol% or less, 22 mol% or less, 21 mol% or less, 20 mol% or less, 19 mol% or less, 18 mol% or less, 17 mol% or less, 16 mol% or less, or 15 mol% or less.

[0025] If the above MPD content is less than 5 mol%, it is undesirable because it cannot provide sufficient structural twisting, and if it exceeds 30 mol%, the flexibility of the chain itself decreases, which is undesirable for securing elongation.

[0026] In addition, the content of the 4,4'-diaminodiphenyl ether (ODA) among the total diamine monomers may be 1 mol% to 30 mol%, preferably the lower limit may be 2 mol% or more, 3 mol% or more, 4 mol% or more, or 5 mol% or more, and the upper limit may be 25 mol% or less, 23 mol% or less, 20 mol% or less, 18 mol% or less, 17 mol% or less, 16 mol% or less, 15 mol% or less, 14 mol% or less, 13 mol% or less, 12 mol% or less, 11 mol% or less, or 10 mol% or less.

[0027] If the above ODA content is less than 1 mol%, the flexibility of the chain is insufficient and is undesirable, and if it exceeds 30 mol%, the strength of the chain is reduced and is undesirable.

[0028] In addition, the paraphenylenediamine (PPD) content in the total diamine monomer may be 1 mol% to 30 mol%, preferably the lower limit may be 2 mol% or more, 3 mol% or more, 4 mol% or more, 5 mol% or more, 6 mol% or more, 7 mol% or more, 8 mol% or more, 9 mol% or more, or 10 mol% or more, and the upper limit may be 25 mol% or less, 24 mol% or less, 23 mol% or less, 22 mol% or less, 21 mol% or less, 20 mol% or less, 19 mol% or less, 18 mol% or less, 17 mol% or less, 16 mol% or less, or 15 mol% or less.

[0029] If the above PPD content is less than 1 mol%, it is undesirable because sufficient strength cannot be secured, and if it exceeds 30 mol%, the flexibility of the chain decreases, which is undesirable for securing elongation.

[0030] In one embodiment, based on a total content of 100 mol% of the total diamine monomer, the content of 4,4'-methylenedianiline (MDA) is 60 to 80 mol%; metaphenylenediamine (MPD) is 5 to 20 mol%; paraphenylenediamine (PPD) is 5 to 20 mol%; and 4,4'-diaminodiphenyl ether (ODA) is 5 to 15 mol%.

[0031] The 4,4'-methylenedianiline (MDA) applied to the polyimide film of the present invention is an aromatic diamine having a structure similar to 4,4'-diaminodiphenyl ether (ODA) and is the most accessible diamine monomer in terms of cost. However, due to differences in structural flexibility and chemical bond strength, there is a problem in that the elongation and tensile strength of the polyimide (PI) are somewhat lower compared to ODA. Accordingly, the present invention achieves an improvement in tensile strength while maintaining elongation through the control of the PI structure by using diamine monomers including MDA, MPD, ODA, and PPD. In particular, tensile strength can be improved by setting the MDA content higher than the ODA content.

[0032] In addition, the polyimide film may contain 90 to 110 mol% of the dianhydride monomer, preferably 95 to 105 mol%, more preferably 98 to 102 mol%, and even more preferably 100 mol%.

[0033] The molar ratio of the above dianhydride monomer to the above diamine monomer may be 1:2 to 2:1, and preferably 1:1.

[0034] In addition, the polyimide film may be a block copolymer composed of two or more blocks. For example, the expression “-(A)a-(B)b-(C)c-(D)d-”, which is a block copolymer of polymerization units A to D, means that the same polymerization units are connected continuously in the form of -(AAABBBBBCCCCDDD)-, and a, b, c, and d represent the ratios of polymerization units A, B, C, and D.

[0035] In addition, the polyimide film may be a block copolymer comprising: a first block comprising a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD) as polymerization units; and a second block comprising a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) as polymerization units.

[0036] Specifically, the above polyimide film includes a first block (MDA / MPD / PMDA) and a second block (ODA / PPD / PMDA) structure, thereby enabling excellent mechanical properties (tensile strength of 180 MPa or more, elongation of 90% or more). In addition, the first block containing MDA / MPD / PMDA forms a structural twist by mixing the MPD-PMDA structure with the MDA-PMDA structure, and can increase elongation by securing free space for polymer chains, while the second block containing ODA / PPD / PMDA can increase strength due to the omnidirectional ring structure of PPD-PMDA and secure elongation by utilizing the flexible structure of ODA-PMDA.

[0037] In addition, with respect to 100 mol% of the total diamine monomer, the content of the first diamine monomer may be 65 mol% to 99 mol%, and the content of the second diamine monomer may be 1 mol% to 35 mol%.

[0038] In addition, the thickness of the polyimide film can be appropriately selected considering the application, usage environment, and physical properties of the polyimide film. For example, the thickness of the polyimide film may be 1 to 100 μm, 15 to 70 μm, 25 to 50 μm, or 30 to 45 μm, but is not limited thereto.

[0039] Another embodiment of the present invention provides a polyimide film that is a block copolymer comprising: a first block comprising a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD) as polymerization units; and a second block comprising a second dianhydride monomer and a second diamine monomer as polymerization units.

[0040] In addition, with respect to 100 mol% of the total diamine monomer, the content of the first diamine monomer may be 65 mol% to 99 mol%, and the content of the second diamine monomer may be 1 mol% to 35 mol%.

[0041] In addition, the second block may include a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD).

[0042] In addition, among the total diamine monomers, the content of the 4,4'-methylenedianiline (MDA) may be 60 mol% or more and less than 100 mol%, the content of the metaphenylenediamine (MPD) may be 5 mol% to 30 mol%, the content of the 4,4'-diaminodiphenyl ether (ODA) may be 1 mol% to 30 mol%, and the content of the paraphenylenediamine (PPD) may be 1 mol% to 30 mol%.

[0043] The tensile strength of the above polyimide film may be 180 MPa or more and the elongation may be 90% or more, the tensile strength is measured using an INSTRON Instron 5564 UTM device and the elongation is measured using an INSTRON Instron 5564 UTM device.

[0044] Another embodiment of the present invention provides a molded article comprising the polyimide film.

[0045] The above-mentioned molded article may be any one selected from the group consisting of secondary batteries, fuel cells, solar cells, electric vehicles, electronic circuit boards, semiconductors, displays, liquid crystal alignment films, motor windings, paints, optical components, heat dissipation materials, and electromagnetic shielding materials, but is not limited thereto. The molded article comprising the polyimide film of the present invention can be widely used in a wide range of industrial fields suitable for the physical properties and characteristics of the molded article.

[0046] Method for manufacturing polyimide film

[0047] The present invention comprises the step of (a) preparing a polyimide film comprising, as polymerization units, a dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a diamine monomer comprising 4,4'-methylenedianiline (MDA), metaphenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA), and paraphenylenediamine (PPD); and

[0048] A method for manufacturing a polyimide film having a tensile strength of 180 MPa or more and an elongation of 90% or more is provided.

[0049] Specifically, the tensile strength is measured using an INSTRON Instron 5564 UTM device, and preferably, the lower limit may be 181 MPa or higher, 182 MPa or higher, 183 MPa or higher, 184 MPa or higher, or 185 MPa or higher, and the upper limit is not specifically limited but may be 400 MPa or lower.

[0050] In addition, the above elongation is measured using an INSTRON Instron 5564 UTM device, and preferably, the lower limit may be 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, or 100%, and the upper limit is not specifically limited but may be 300% or less.

[0051] In addition, the polyimide film may be a block copolymer composed of two or more blocks.

[0052] Additionally, step (a) may include: (a-1) a step of preparing a first block comprising a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD) as polymerization units; and (a-2) a step of preparing a second block comprising a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) as polymerization units.

[0053] Additionally, after step (a-2), the method may further include: (a-3) a step of mixing the first block and the second block to prepare a polyamic acid solution; and (a-4) a step of imidizing the polyamic acid solution to prepare a polyimide film which is a block copolymer.

[0054] In addition, with respect to 100 mol% of the total diamine monomer, the content of the first diamine monomer may be 65 mol% to 99 mol%, and the content of the second diamine monomer may be 1 mol% to 35 mol%.

[0055] In addition, among the total diamine monomers, the content of the 4,4'-methylenedianiline (MDA) may be 60 mol% or more and less than 100 mol%, the content of the metaphenylenediamine (MPD) may be 5 mol% to 30 mol%, the content of the 4,4'-diaminodiphenyl ether (ODA) may be 1 mol% to 30 mol%, and the content of the paraphenylenediamine (PPD) may be 1 mol% to 30 mol%.

[0056] Each of the above first block and second block can be manufactured in the presence of a solvent.

[0057] The above solvent may include one or more selected from the group consisting of N,N'-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), diethylacetamide (DEAc), N-ethyl-2-pyrrolidone (NEP), N,N'-diethylformamide (DEF), dimethylpropanamide (DMPA), and gamma-butyrolactone (GBL), and preferably N,N'-dimethylformamide (DMF) may be used.

[0058] The above polyamic acid solution is at a temperature of 23℃ and 1s -1 The viscosity measured under shear rate conditions can be in the range of 200 to 500,000 cP. Specifically, the lower limit of the viscosity of the polyamic acid solution may be 1,000 cP or more, 5,000 cP or more, 10,000 cP or more, 20,000 cP or more, 50,000 cP or more, 80,000 cP or more, 100,000 cP or more, 150,000 cP or more, 170,000 cP or more, 180,000 cP or more, or 190,000 cP or more, and the upper limit may be 480,000 cP or less, 450,000 cP or less, 400,000 cP or less, 380,000 cP or less, 350,000 cP or less, 320,000 cP or less, 300,000 cP or less, or 250,000 cP or less. By controlling the viscosity range of the above polyamic acid solution, a polyimide film with excellent processability and desired physical properties can be manufactured.

[0059] The above polyamic acid solution may have a solid content of 10 to 50 weight% based on 100 weight% of the polyamic acid solution. The lower weight% limit of the solid content may be 11, 12, 13, 14, 15, 16, 17, or 18 weight% or more, and the upper weight% limit of the solid content may be 45, 40, 35, 30, 27, 25, 23, 21, or 20 weight% or less. By controlling the solid content of the above polyamic acid solution, the increase in viscosity can be controlled and the process time during the curing process can be shortened.

[0060] In step (a-4), a dehydrating agent and a catalyst may be added to the polyamic acid solution to imidize the polyamic acid solution. The dehydrating agent is not particularly limited as long as it can promote a ring-closing reaction through dehydration of the polyamic acid, and examples of the dehydrating agent include acetic anhydride. The catalyst is not particularly limited as long as it can promote a ring-closing reaction of the polyamic acid, and examples of the catalyst include tertiary amines, such as quinoline, isoquinoline (IQ), β-picoline (BP), etc.

[0061] The imidation reaction performed in step (a-4) above has an imidation rate of 97 to 100%, preferably 98 to 100%, more preferably 99 to 100%, and most preferably 100%.

[0062] After step (a-4), (a-5) a step of drying the polyimide film may be additionally included.

[0063] In addition, the above drying may be performed by one or more combinations selected from the group consisting of natural drying, pressurized drying, hot air drying, spray drying, film drying, vacuum drying, freeze drying, spray freeze drying, electromagnetic wave drying, and flash drying methods.

[0064] The polyimide film and the method for manufacturing the same according to the present invention can reduce costs by introducing methylenedianiline (4,4'-Methylenedianiline, MDA) and improve mechanical properties (elongation and tensile strength) by controlling the structure of the polyimide by deriving an optimal monomer combination.

[0065] In addition, the polyimide film according to the present invention contains a high content of MDA, thereby increasing price competitiveness and providing excellent productivity and process efficiency.

[0066] In addition, the molded article comprising the polyimide film of the present invention has the effect of being widely used in a wide range of industrial fields (especially secondary batteries).

[0067] Examples are provided to aid in understanding the present invention. The following examples are provided merely to facilitate a better understanding of the invention, and the scope of the invention is not limited by these examples.

[0068] <Example>

[0069] [Preparation of Polyamic Acid Solution]

[0070] Preparation Example 1

[0071] A solvent dimethylformamide (DMF) was introduced into a 500 ml reactor equipped with a stirrer and a nitrogen injection / discharge pipe, and a first diamine monomer containing 70 mol% of 4,4'-methylenedianiline (MDA) and 10 mol% of metaphenylenediamine (MPD) and a first dianhydride monomer containing 75 mol% of pyromellitic dianhydride (PMDA) were introduced and reacted at 25°C for 2 hours to prepare a first solution containing a first block (MDA / MPD / PMDA).

[0072] Next, the solvent dimethylformamide (DMF) was introduced into a 500 ml reactor equipped with a stirrer and a nitrogen injection / discharge tube, and a second diamine monomer containing 7.5 mol% of 4,4'-diaminodiphenyl ether (ODA) and 12.5 mol% of paraphenylenediamine (PPD) and a second dianhydride monomer containing 22 mol% of pyromellitic dianhydride (PMDA) were introduced and reacted at 25°C for 2 hours to prepare a second solution containing a second block (ODA / PPD / PMDA).

[0073] Subsequently, the first solution and the second solution were mixed, and 3 mol% of PMDA was additionally added and reacted at 25°C for 2 hours to prepare a polyamic acid solution (solid content 18.5 wt%, viscosity at 23°C 200,000 cP).

[0074] Preparation Examples 2 and 3

[0075] A polyamic acid solution was prepared in the same manner as in Preparation Example 1, except that the content ratios of MDA, MPD, ODA, PPD, and PMDA were adjusted as shown in Table 1 below.

[0076] Manufacturing Comparative Example 1

[0077] A polyamic acid solution of a random structure was prepared by adding the solvent dimethylformamide (DMF) to a 500 ml reactor equipped with a stirrer and a nitrogen injection / discharge pipe, adding 100 mol% of 4,4'-methylenedianiline (MDA) and 100 mol% of pyromellitic dianhydride (PMDA), and reacting at 25°C for 2 hours.

[0078] Comparative Manufacturing Example 2

[0079] A polyamic acid solution of a random structure was prepared in the same manner as in Comparative Example 1, except that 85 mol% of 4,4'-methylenedianiline (MDA) and 15 mol% of metaphenylenediamine (MPD) were used instead of 100 mol% of 4,4'-methylenedianiline (MDA) as in Comparative Example 1.

[0080] Manufacturing Comparative Example 3

[0081] A polyamic acid solution of a random structure was prepared in the same manner as in Comparative Example 1, except that 70 mol% of 4,4'-methylenedianiline (MDA) and 30 mol% of metaphenylenediamine (MPD) were used instead of 100 mol% of 4,4'-methylenedianiline (MDA) as in Comparative Example 1.

[0082] Comparative Manufacturing Example 4

[0083] A polyamic acid solution of a random structure was prepared in the same manner as in Comparative Example 1, except that 70 mol% of 4,4'-methylenedianiline (MDA) and 30 mol% of paraphenylenediamine (PPD) were used instead of 100 mol% of 4,4'-methylenedianiline (MDA) as in Comparative Example 1.

[0084] Comparative Manufacturing Example 5

[0085] A polyamic acid solution of a random structure was prepared in the same manner as in Comparative Example 1, except that 70 mol% of 4,4'-methylenedianiline (MDA) and 30 mol% of 4,4'-diaminodiphenyl ether (ODA) were used instead of 100 mol% of 4,4'-methylenedianiline (MDA) in Comparative Example 1.

[0086] Comparative Manufacturing Example 6

[0087] A solvent dimethylformamide (DMF) was added to a 500 ml reactor equipped with a stirrer and a nitrogen injection / discharge pipe, and 70 mol% of 4,4'-methylenedianiline (MDA), 10 mol% of metaphenylenediamine (MPD), 10 mol% of 4,4'-diaminodiphenyl ether (ODA), 10 mol% of paraphenylenediamine (PPD), and 100 mol% of pyromellitic dianhydride (PMDA) were added and reacted at 25°C for 2 hours to prepare a polyamic acid solution of a random structure.

[0088] Manufacturing Comparative Example 7

[0089] A solvent dimethylformamide (DMF) was added to a 500 ml reactor equipped with a stirrer and a nitrogen injection / discharge pipe, and 60 mol% of 4,4'-methylenedianiline (MDA), 15 mol% of metaphenylenediamine (MPD), 10 mol% of 4,4'-diaminodiphenyl ether (ODA), 15 mol% of paraphenylenediamine (PPD), and 100 mol% of pyromellitic dianhydride (PMDA) were added and reacted at 25°C for 2 hours to prepare a polyamic acid solution of a random structure.

[0090] [Manufacture of Polyimide Film]

[0091] Example 1

[0092] A polyamic acid solution prepared according to Preparation Example 1 was mixed with a catalyst (IQ, isoquinoline or BP, β-picoline) and a dehydrating agent (AA, acetic anhydride) to prepare a mixed solution, and the degassed mixed solution was applied to a glass plate. Subsequently, the solvent-to-solid ratio was calculated using an applicator and the solution was applied to the surface to ensure uniform distribution. Afterward, a polyimide film was prepared by curing under conditions of 130°C (4 min) → 280°C (4 min) → 420°C (4 min). At this time, the film thickness was prepared to be 25 μm.

[0093] Examples 2 and 3

[0094] A polyimide film was prepared in the same manner as in Example 1, except that instead of using the polyamic acid solution prepared according to Preparation Example 1 in Example 1, the polyamic acid solutions prepared according to Preparation Examples 2 and 3, respectively, were used.

[0095] Comparative Examples 1 to 7

[0096] A polyimide film was prepared in the same manner as in Example 1, except that instead of using the polyamic acid solution prepared according to Preparation Example 1 in Example 1, each of the polyamic acid solutions prepared according to Preparation Comparative Examples 1 to 7 was used.

[0097]

[0098] Table 1 below describes the composition and content of the dianhydride monomer and diamine monomer used to prepare the polyimide films according to Examples 1 to 3 and Comparative Examples 1 to 7, as well as their structures.

[0099] Classification PAA Solution Anhydrous Monomer (mol%) Diamine Monomer (mol%) Structure PMDAMDAMPDODAPPD First Block Second Block Example 1 Preparation Example 1 10070107.512.5MDA / MPD / PMDAODA / PPD / PMDA Example 2 Preparation Example 2 10070101010MDA / MPD / PMDAODA / PPD / PMDA Example 3 Preparation Example 3 10060151015MDA / MPD / PMDAODA / PPD / PMDA Comparative Example 1 Preparation Comparative Example 1 100100---Random Comparative Example 2 Preparation Comparative Example 2 1008515--Random Comparative Example 3 Preparation Comparative Example 3 1007030--Random Comparative Example 4 Preparation Comparative Example 410070--30 Random Comparative Example 5 Manufacturing Comparative Example 5 10070-30-Random Comparative Example 6 Manufacturing Comparative Example 6 10070101010 Random Comparative Example 7 Manufacturing Comparative Example 7 10060151015 Random

[0100] <Experimental Example>

[0101] Experimental Example 1: Evaluation of Physical Properties of Polyimide Film

[0102] (1) Tensile strength

[0103] Using an INSTRON Instron 5564 UTM instrument, samples with a length of 400 mm and a width of 10 mm were prepared, and the tensile strength of the polyimide films prepared according to the examples and comparative examples was measured at a speed (20 mm / min), and the average of 10 samples was calculated. The results are shown in Table 2 below.

[0104] (2) Elongation

[0105] The elongation of the polyimide films according to the examples and comparative examples was measured under room temperature conditions using the ASTM D882 method with an INSTRON Instron 5564 UTM instrument. The results are shown in Table 2 below.

[0106] Classification Tensile Strength (Mpa) Elongation (%) Example 1 195 100 Example 2 185 110 Example 3 185 105 Comparative Example 1 140 55 Comparative Example 2 150 95 Comparative Example 3 140 110 Comparative Example 4 210 60 Comparative Example 5 130 70 Comparative Example 6 170 90 Comparative Example 7 180 85

[0107] According to Table 2, it was confirmed that the polyimide films according to Examples 1 to 3, which include the first block (MDA / MPD / PMDA) and the second block (ODA / PPD / PMDA), have a tensile strength of 180 MPa or more and an elongation of 90% or more.

[0108] Meanwhile, in the case of Comparative Examples 1 to 5, which contain only some of the four types of diamines, it was confirmed that the tensile strength was less than 180 MPa (Comparative Examples 1 to 3 and Comparative Example 5) or the elongation was less than 90% (Comparative Examples 1, 4, and 5). In addition, in the case of Comparative Examples 6 and 7, which contain a random structure rather than a block structure with the same composition as Examples 2 and 3, it was confirmed that the tensile strength was less than 180 MPa (Comparative Example 6) or the elongation was less than 90% (Comparative Example 7).

[0109] From these results, the polyimide film according to the present invention was able to achieve excellent mechanical properties (tensile strength of 180 MPa or more, elongation of 90% or more) by including a first block (MDA / MPD / PMDA) and a second block (ODA / PPD / PMDA) structure. Specifically, the first block of the polyimide film according to the present invention, which includes MDA / MPD / PMDA, forms a structural twist by mixing the MPD-PMDA structure with the MDA-PMDA structure and can increase elongation by securing a free space for polymer chains, and the second block, which includes ODA / PPD / PMDA, can increase strength due to the omnidirectional ring structure of PPD-PMDA and secure elongation by utilizing the flexible structure of ODA-PMDA.

[0110] Therefore, the present invention can simultaneously improve elongation and tensile strength through monomer structure control by including MDA / MPD / ODA / PPD / PMDA as polymerization units. In addition, by significantly improving mechanical properties while manufacturing polyimide films economically, PI materials can be applied to a wider variety of fields.

[0111] The specification omits detailed descriptions of matters that can be sufficiently recognized and inferred by those skilled in the art of the present invention, and various modifications are possible within the scope of not altering the technical concept or essential configurations of the present invention, in addition to the specific examples described in this specification. Accordingly, the present invention may be implemented in a manner different from that specifically described and exemplified in this specification, and this is a matter that can be understood by those skilled in the art.

Claims

1. A dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a diamine monomer comprising 4,4'-methylenedianiline (MDA), metaphenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA), and paraphenylenediamine (PPD) as polymerization units, Polyimide film having a tensile strength of 180 MPa or more and an elongation of 90% or more.

2. In Paragraph 1, A polyimide film having a 4,4'-methylenedianiline (MDA) content of 60 mol% or more and less than 100 mol% among the total diamine monomers.

3. In Paragraph 1, A polyimide film having a metaphenylenediamine (MPD) content of 5 mol% to 30 mol% among the total diamine monomers.

4. In Paragraph 1, A polyimide film having a content of 4,4'-diaminodiphenyl ether (ODA) of 1 mol% to 30 mol% among the total diamine monomers.

5. In Paragraph 1, A polyimide film having a paraphenylenediamine (PPD) content of 1 mol% to 30 mol% among the total diamine monomers.

6. In Paragraph 1, A polyimide film in which the above polyimide film is a block copolymer composed of two or more blocks.

7. In Paragraph 1, The above polyimide film A first block comprising, as polymerization units, a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD); and A polyimide film that is a block copolymer comprising a second block comprising a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) as polymerization units.

8. In Paragraph 7, Based on 100 mol% of total diamine monomer, The content of the first diamine monomer is 65 mol% to 99 mol%, and A polyimide film having a second diamine monomer content of 1 mol% to 35 mol%.

9. A first block comprising, as polymerization units, a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD); and A polyimide film that is a block copolymer comprising a second block including a second dianhydride monomer and a second diamine monomer as polymerization units.

10. In Paragraph 9, Based on 100 mol% of total diamine monomer, The content of the first diamine monomer is 65 mol% to 99 mol%, and A polyimide film having a second diamine monomer content of 1 mol% to 35 mol%.

11. In Paragraph 9, A polyimide film having a 4,4'-methylenedianiline (MDA) content of 60 mol% or more and less than 100 mol% among the total diamine monomers.

12. In Paragraph 9, A polyimide film having a metaphenylenediamine (MPD) content of 5 mol% to 30 mol% among the total diamine monomers.

13. In Paragraph 9, A polyimide film wherein the second block comprises a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD).

14. In Paragraph 13, A polyimide film having a content of 4,4'-diaminodiphenyl ether (ODA) of 1 mol% to 30 mol% among the total diamine monomers.

15. In Paragraph 13, A polyimide film having a paraphenylenediamine (PPD) content of 1 mol% to 30 mol% among the total diamine monomers.

16. In Paragraph 9, A polyimide film having a tensile strength of 180 MPa or more and an elongation of 90% or more.

17. (a) a step of preparing a polyimide film comprising, as polymerization units, a dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a diamine monomer comprising 4,4'-methylenedianiline (MDA), metaphenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD); and A method for manufacturing a polyimide film having a tensile strength of 180 MPa or more and an elongation of 90% or more.

18. In Paragraph 17, A method for manufacturing a polyimide film in which the content of the 4,4'-methylenedianiline (MDA) among the total diamine monomers is 60 mol% or more and less than 100 mol%.

19. In paragraph 18, step (a) (a-1) a step of preparing a first block comprising a first dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a first diamine monomer comprising 4,4'-methylenedianiline (MDA) and metaphenylenediamine (MPD) as polymerization units; and (a-2) a step of preparing a second block comprising a second dianhydride monomer comprising pyromellitic dianhydride (PMDA) and a second diamine monomer comprising 4,4'-diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) as polymerization units; a method for manufacturing a polyimide film comprising: