Polyimide precursor composition and method for producing insulating coating layer using same

Abstract

The object of the present invention is to provide a method for forming a polyimide insulating coating layer without defects even when the temperature is rapidly increased. The present invention provides a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride, and a diamine component, and a solvent, wherein the polyamic acid has a water vapor permeability coefficient of 1.7 g mm / (m 2 The present invention relates to a polyimide precursor composition for forming a polyimide insulating coating layer, which is capable of producing a polyimide film having a film life of greater than 24 h.

Description

[Technical field]

[0001] The present invention relates to a polyimide precursor composition capable of efficiently producing a polyimide insulating coating layer having excellent heat resistance and mechanical properties, and a method for producing an insulating coating layer using the same. [Background technology]

[0002] Polyimide resins are known as resins with extremely excellent heat resistance and are widely used in various fields. For example, they are used as insulating layers for electric wires with high requirements because they have a low dielectric constant and excellent mechanical properties in addition to high heat resistance. Patent Document 1 describes an insulated electric wire characterized in that an insulating layer made of imidized polyamic acid obtained by reacting biphenyltetracarboxylic dianhydride with 4,4'-diaminodiphenyl ether is provided on a core wire, and describes that this polyimide insulated electric wire has excellent resistance to thermal degradation.

[0003] Polyimide may become crystalline depending on the combination of the tetracarboxylic acid component and the diamine component, and as a result, the conditions for imidizing the polyamic acid, which is a polyimide precursor, may be limited. For example, when 3,3',4,4'-biphenyltetracarboxylic dianhydride is used as the tetracarboxylic acid component, a crystalline polyimide resin is easily obtained, but depending on the imidization conditions, partial crystallization is likely to occur, especially when imidization is performed by a short-time heat treatment with rapid temperature increase. Therefore, when a polyimide layer is formed by imidizing a polyamic acid using 3,3',4,4'-biphenyltetracarboxylic dianhydride as the tetracarboxylic acid component, it may not be possible to increase the temperature increase rate and increase productivity.

[0004] A method for forming a polyimide insulating coating layer by imidizing a polyamic acid using 3,3',4,4'-biphenyltetracarboxylic dianhydride as the tetracarboxylic acid component, in which a polyimide insulating coating layer can be formed without crystallization even when the temperature is rapidly increased, is described in Patent Document 2. Specifically, Patent Document 2 describes a method for producing a polyimide insulating coating layer, which includes a step of applying a polyimide precursor composition to a substrate and baking the composition, in which the polyimide precursor composition contains a polyamic acid using 3,3',4,4'-biphenyltetracarboxylic dianhydride as the tetracarboxylic acid component and a basic compound selected from the group consisting of imidazoles and amine compounds, and in the baking step, the polyimide precursor composition is heated for 10 to 180 seconds, the average heating rate from 100°C to 280°C is 5°C / s or more, and the maximum heating temperature is 300 to 500°C. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 61-273806 [Patent Document 2] International Publication No. 2014 / 142173 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a method for forming a polyimide insulating coating layer without defects even when the temperature is rapidly raised when a polyimide insulating coating layer is formed by imidizing a polyamic acid using 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride as a tetracarboxylic acid component. That is, the present invention aims to provide a polyimide precursor composition that can form an insulating coating layer of a polyimide resin having excellent heat resistance and mechanical properties in a short time without causing crystallization, and to provide an industrially advantageous method for producing an insulating coating layer by using the polyimide precursor composition to form an insulating coating layer of a polyimide resin having excellent heat resistance and mechanical properties in a short time without causing crystallization. [Means for solving the problem]

[0007] The present invention relates to the following items: 1. A polyimide precursor composition comprising a polyamic acid and a solvent, The polyamic acid is a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride and a diamine component, and the water vapor permeability coefficient is 1.7 g mm / (m 2 1. A polyimide precursor composition for forming a polyimide insulating coating layer, which is capable of producing a polyimide film having a hardness of greater than 100% (24 h). 2. A polyimide precursor composition for forming a polyimide insulating coating layer according to item 1, wherein the tetracarboxylic acid component contains 2,3,3',4'-biphenyltetracarboxylic dianhydride, and the diamine component contains p-phenylenediamine and 4,4'-diaminodiphenyl ether, or 50 to 100 mol % of either one of them. 3. A polyimide precursor composition for forming a polyimide insulating coating layer according to item 1, wherein the tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the diamine component comprises one or more diamines selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, and contains 30 to 100 mol % of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane. 4. A polyimide precursor composition for forming a polyimide insulating coating layer according to item 1, wherein the tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the diamine component is composed of one or more diamines selected from the group consisting of 4,4'-diaminodiphenyl ether and 4,4'-methylenebis(2,6-xylidine), and contains 20 to 100 mol % of 4,4'-methylenebis(2,6-xylidine).

[0008] 5. A method for producing a polyimide insulating coating layer, comprising the steps of applying a polyimide precursor composition to a substrate and baking the composition, The polyimide precursor composition contains a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride and a diamine component, and the polyamic acid has a water vapor permeability coefficient of 1.7 g mm / (m) by being heat-treated under conditions of a maximum heating temperature of 300 to 500°C. 2 -24h) and can produce polyimide films with a longer life. In the baking process, The time for heating the polyimide precursor composition is 10 to 180 seconds, The average heating rate from 100°C to 280°C is 5°C / s or more. A method for producing an insulating coating layer, characterized in that the maximum heating temperature is 300 to 500°C. 6. The method for producing an insulating coating layer according to item 5, wherein the tetracarboxylic acid component contains 2,3,3',4'-biphenyltetracarboxylic dianhydride, and the diamine component contains p-phenylenediamine and 4,4'-diaminodiphenyl ether, or 50 to 100 mol % of either one of them. 7. A method for producing an insulating coating layer according to item 5, wherein the tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the diamine component comprises one or more diamines selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, and contains 30 to 100 mol % of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane. 8. The method for producing an insulating coating layer according to item 5, wherein the tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the diamine component is composed of one or more diamines selected from the group consisting of 4,4'-diaminodiphenyl ether and 4,4'-methylenebis(2,6-xylidine), and contains 20 to 100 mol % of 4,4'-methylenebis(2,6-xylidine). Effect of the Invention

[0009] According to the present invention, a polyimide precursor composition can be provided that can form an insulating coating layer of a polyimide resin having excellent heat resistance and mechanical properties in a short time without causing crystallization. That is, by using the polyimide precursor composition of the present invention, an insulating coating layer of a polyimide resin having excellent heat resistance and mechanical properties can be formed in a short time without causing crystallization. The polyimide precursor composition of the present invention and the method for producing an insulating coating layer of the present invention using the same can be particularly suitably applied to the production of an insulated wire, and can efficiently produce an insulated wire having excellent heat resistance and a defect-free insulating coating layer with high reliability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The polyimide precursor composition of the present invention uses 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride as a tetracarboxylic acid component, and is characterized by containing a polyamic acid that provides a polyimide film having a specific water vapor permeability coefficient.

[0011] The polyamic acid used in the present invention can be obtained by reacting a tetracarboxylic acid component (the tetracarboxylic acid component also includes a tetracarboxylic dianhydride) with a diamine component in a solvent, for example, in water or an organic solvent, or in a mixed solvent of water and an organic solvent.

[0012] This polyamic acid is obtained from a tetracarboxylic acid component containing 50 to 100 mol % of biphenyltetracarboxylic dianhydride and a diamine component. Biphenyltetracarboxylic dianhydride is a general term including a plurality of isomers, and includes 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, and 2,2',3,3'-biphenyltetracarboxylic dianhydride. In the present invention, in particular, a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride and a diamine component is used.

[0013] In addition, the polyamic acid used in the present invention has a water vapor permeability coefficient of 1.7 g mm / (m 2 It is possible to produce polyimide films with a film thickness of greater than 24h.

[0014] The tetracarboxylic acid component used in the present invention is mainly composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride, i.e., 50 to 100 mol %, more preferably 70 to 100 mol %. In particular, from the viewpoint of heat resistance and mechanical properties, it is preferable to use 3,3',4,4'-biphenyltetracarboxylic dianhydride as the main component. As described above, when 3,3',4,4'-biphenyltetracarboxylic dianhydride is used as the tetracarboxylic acid component, partial crystallization is likely to occur when imidization is performed by a short-term heat treatment with rapid temperature increase. However, according to the present invention, the polyamic acid has a water vapor permeability coefficient of 1.7 g·mm / (m 2 In the case where a polyimide film having a thickness greater than 100 nm (24 h) can be produced, a polyimide layer can be formed without crystallization even when the temperature is raised rapidly.

[0015] In the present invention, 2,2',3,3'-biphenyltetracarboxylic dianhydride may be used in a range of 50 mol% or less, or a tetracarboxylic acid component (tetracarboxylic dianhydride) other than biphenyltetracarboxylic dianhydride may be used in a range of 50 mol% or less. The tetracarboxylic dianhydride that can be used in combination with biphenyltetracarboxylic dianhydride in the present invention is not particularly limited, but aromatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides are preferred in terms of the characteristics of the resulting polyimide. For example, pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, oxydiphthalic dianhydride, diphenylsulfonetetracarboxylic dianhydride, p-terphenyltetracarboxylic dianhydride, m-terphenyltetracarboxylic dianhydride, cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and the like can be preferably mentioned. When a tetracarboxylic acid component other than biphenyltetracarboxylic dianhydride is used, it is particularly preferable to use 4,4'-oxydiphthalic dianhydride or pyromellitic dianhydride in view of the properties of the resulting polyimide. The above-mentioned tetracarboxylic acid dianhydride does not need to be one type, and may be a mixture of multiple types.

[0016] Diamines that can be used in the present invention are not particularly limited, but include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl-4,4'-biphenyldiamine, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl ether, 4,4 ... 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl ,4'-Diaminodiphenyl sulfone, 4,4'-diaminodiphenylpropane, 2,4-diaminotoluene, bis(4-amino-3-carboxyphenyl)methane, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,4-bis(β-amino-tert-butyl)toluene, bis(p-β-amino-tert-butylphenyl)ether, bis(p-β-methyl-6-aminophen aromatic diamines such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-methylenebis(2,6-xylidine), α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, diamines containing alicyclic structures such as di(p-aminocyclohexyl)methane and 1,4-diaminocyclohexane, hexamethylenediamine, , heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,Suitable examples of the diamine include aliphatic diamines such as 17-diaminoeicosadecane, 1,10-diamino-1,10-dimethyldecane, and 1,12-diaminooctadecane. The diamines mentioned above do not have to be of one type, and may be a mixture of multiple types.

[0017] Among the above, the aromatic diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, m-xylylenediamine, p-xylylenediamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, More preferred are p-phenyl]propane, 4,4'-methylenebis(2,6-xylidine), and α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, and more preferred are aliphatic diamines such as hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 2,11-diaminododecane, and 1,12-diaminooctadecane. Of these, it is particularly preferred to use at least one of p-phenylenediamine and 4,4'-diaminodiphenyl ether in view of the properties of the resulting polyimide.

[0018] The polyamic acid used in the present invention has a water vapor permeability coefficient of 1.7 g mm / (m 2 It is necessary to be able to manufacture polyimide films with a water vapor permeability coefficient of 1.8 g mm / (m 2 It is preferable that a polyimide film having a water vapor permeability coefficient of less than this value can be produced. If imidization is performed by a short heat treatment with rapid heating in the production of a polyimide insulating coating layer, partial crystallization is likely to occur.

[0019] Here, crystallization in the imidization process will be described. In the imidization process, the evaporation of the solvent and the imidization reaction occur in parallel. When the temperature rise rate is high, the amount of solvent evaporated is small relative to the progress of the imidization reaction, and the amount of remaining solvent is relatively large. When the imidization of the polyamic acid progresses and imide bonds are formed, the solubility of the molecular chain in the solvent decreases. Therefore, in a state where the amount of remaining solvent is relatively large, the molecular chain is likely to crystallize and precipitate. On the other hand, when the temperature rise rate is low, the amount of solvent evaporated is large relative to the progress of the imidization reaction, and the remaining solvent is small, so crystallization is unlikely to occur. Since the polyamic acid used in the polyimide precursor composition of the present invention can obtain a polyimide resin that is easily permeable to gas, the solvent is easily evaporated, and the problem of crystallization is unlikely to occur under conditions of a high temperature rise rate.

[0020] The water vapor permeability coefficient of the polyimide film obtained by heat treatment under conditions of a maximum heating temperature of 300 to 500°C is 1.7 g mm / (m 2 Examples of polyamic acids having a molecular weight greater than 24 h include polyamic acids containing 2,3,3',4'-biphenyltetracarboxylic dianhydride as a tetracarboxylic acid component. In this case, the diamine component preferably contains 50 to 100 mol % of paraphenylenediamine and / or 4,4'-diaminodiphenyl ether.

[0021] Further, the polyamic acid may be a polyamic acid containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride as a tetracarboxylic acid component, and containing 30 to 100 mol % of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane as a diamine component, which is composed of one or more diamines selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane.

[0022] Further, the polyamic acid may be a polyamic acid containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride as a tetracarboxylic acid component, and containing 20 to 100 mol % of 4,4'-methylenebis(2,6-xylidine) as a diamine component, which is composed of one or more diamines selected from the group consisting of 4,4'-diaminodiphenyl ether and 4,4'-methylenebis(2,6-xylidine).

[0023] The polyamic acid used in the present invention can be obtained as a polyamic acid solution by reacting approximately equimolar amounts of tetracarboxylic dianhydride and diamine in a solvent at a relatively low temperature of 100° C. or less, preferably 80° C. or less, in order to suppress the imidization reaction.

[0024] Although not limited thereto, the reaction temperature is usually 25° C. to 100° C., preferably 40° C. to 80° C., and more preferably 50° C. to 80° C., and the reaction time is about 0.1 to 24 hours, and preferably about 2 to 12 hours. By setting the reaction temperature and reaction time within the above ranges, a high molecular weight polyamic acid solution can be easily obtained with high production efficiency.

[0025] The reaction can be carried out in an air atmosphere, but is usually carried out in an inert gas atmosphere, preferably nitrogen gas atmosphere.

[0026] The approximately equimolar amounts of tetracarboxylic dianhydride and diamine are, specifically, such that the molar ratio [tetracarboxylic dianhydride / diamine] is about 0.90 to 1.10, and preferably about 0.95 to 1.05.

[0027] The solvent used in the present invention may be any solvent capable of polymerizing polyamic acid, and may be a water solvent or an organic solvent. The solvent may be a mixture of two or more kinds, and a mixed solvent of two or more kinds of organic solvents or a mixed solvent of water and one or more kinds of organic solvents may be suitably used.

[0028] The organic solvent that can be used in the present invention is not particularly limited, but examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, hexamethylphosphorotriamide, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, tetrahydrofuran, bis[2-(2-methoxyethoxy)ethyl]ether, 1,4-dioxane, dimethyl sulfoxide, dimethyl sulfone, diphenyl ether, sulfolane, diphenyl sulfone, tetramethylurea, anisole, m-cresol, phenol, and γ-butyrolactone.

[0029] The solvent used in this reaction may be the solvent contained in the polyimide precursor composition of the present invention.

[0030] The polyamic acid used in the present invention is not limited, but it is preferable that the logarithmic viscosity measured at a temperature of 30° C. and a concentration of 0.5 g / 100 mL is 0.2 or more, preferably 0.4 or more, and particularly preferably 0.6 or more. If the logarithmic viscosity is lower than the above range, it may be difficult to obtain a polyimide with high properties because the molecular weight of the polyamic acid is low.

[0031] The polyimide precursor composition used in the present invention has a solids concentration attributable to polyamic acid that is not limited, but is preferably 5% by mass to 45% by mass, more preferably 5% by mass to 40% by mass, and even more preferably more than 5% by mass to 30% by mass, based on the total amount of polyamic acid and solvent. If the solids concentration is lower than 5% by mass, handling during use may become difficult, and if it is higher than 45% by mass, the solution may lose fluidity.

[0032] In addition, the solution viscosity at 30°C of the polyimide precursor composition used in the present invention is not limited, but is preferably 1000 Pa·sec or less, more preferably 0.5 to 500 Pa·sec, even more preferably 1 to 300 Pa·sec, and particularly preferably 2 to 200 Pa·sec, which is suitable for ease of handling.

[0033] The polyimide precursor composition becomes polyimide by removing the solvent and imidizing (dehydration ring closure) by heat treatment, and by using the polyimide precursor composition of the present invention as described above, it becomes possible to adopt a process of heating in a short time and baking at a high temperature to form a polyimide insulating coating layer. Here, heating in a short time and baking at a high temperature refers to, for example, a process in which the polyimide precursor composition is heated for 10 to 180 seconds, the temperature is raised under conditions of an average heating rate from 100°C to 280°C of 5°C / s or more, and the maximum heating temperature is 300 to 500°C.

[0034] In the present invention, the polyimide insulating coating layer is formed by applying the polyimide precursor composition as described above to a substrate by a known method and heating (baking). In this baking step, the time for heating the polyimide precursor composition (time in the heating furnace when heating in a heating furnace) is set to 10 to 180 seconds, the average heating rate from 100°C to 280°C is set to 5°C / s or more, and the maximum heating temperature can be set to 300 to 500°C. The upper limit of the average heating rate from 100°C to 280°C is not particularly limited, but is preferably, for example, 50°C / s or less.

[0035] In the present invention, the average heating rate from 100°C to 300°C may be 5°C / s or more (i.e., from 100°C to 300°C within 40 seconds), and the average heating rate from 100°C to the maximum heating temperature (300 to 500°C) may be 5°C / s or more. The average heating rate up to 100°C is not particularly limited, but may be 5°C / s or more.

[0036] In the present invention, there are no limitations on the conditions for heating from room temperature to the maximum heating temperature as long as the average heating rate from 100°C to 280°C is 5°C / s or more (i.e., within 36 seconds from 100°C to 280°C), and the temperature may be raised at a constant rate, or the rate may be changed during the heat treatment, or the temperature may be raised in stages.

[0037] The heat treatment for imidization can be carried out, for example, in an air atmosphere or an inert gas atmosphere.

[0038] The polyimide precursor composition of the present invention can also be heat-treated under conditions other than those mentioned above to form a polyimide insulating coating layer.

[0039] The substrate is not particularly limited and may be appropriately selected depending on the application. The thickness of the polyimide insulating coating layer is also not particularly limited and may be appropriately selected depending on the application.

[0040] The polyimide insulating coating layer obtained by the present invention is an insulating member (coating layer) having high voltage resistance, heat resistance, and moist heat resistance, and is therefore particularly suitable for use in electric and electronic parts, the automotive field, the aerospace field, and the like, and can also be used in the fields of coils for hybrid vehicle motors and ultra-small motors. EXAMPLES

[0041] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0042] The methods for measuring the properties used in the following examples are as follows. <Solid content concentration> The sample solution (w 1 The sample was heated in a hot air dryer at 120°C for 10 minutes, 250°C for 10 minutes, and then 350°C for 30 minutes, and the mass after the heat treatment (the mass was w 2 The solid content concentration [mass %] was calculated by the following formula.

[0043] Solid content concentration [mass%]=(w2 / w 1 ) x 100 <Solution viscosity (rotational viscosity)> Measurement was performed at 30°C using a Tokimec E-type viscometer. <Observation of the state of the insulating coating layer (coating film evaluation)> The state of the resulting coating layer was visually observed. A completely free coating layer was rated as good, and a coating layer with a cloudy area of ​​more than 10% was rated as cloudy. "Cloudy" indicates that at least a portion of the polyimide resin was crystallized. <Measurement of heating rate> In the coating layer formation process, the time required for the sample temperature to change from 100°C to 280°C was measured using a measurement unit NR-TH08 manufactured by Keyence Corporation and analysis software WAVE LOGGER. <Water vapor permeability coefficient> The measurements were carried out at 40°C and a relative humidity of 90% in accordance with JIS K7129 Method B. <Elastic modulus, tensile strength, tensile elongation> The prepared polyimide precursor composition was applied onto a glass substrate, heated in a hot air oven at 80°C for 30 minutes, and then heated at 350°C for 30 minutes to cure the composition, producing a polyimide film having a thickness of approximately 25 μm. The obtained polyimide film was cut into a width of 10 mm and a length of 100 mm to prepare a test piece. The tensile modulus, tensile strength, and tensile elongation of the test piece were measured using a tensile tester (Orientec; Tensilon RTG-1225) under the conditions of a temperature of 25°C, a humidity of 50% RH, a crosshead speed of 50 mm / min, and a chuck distance of 50 mm.

[0044] The abbreviations of the compounds used in the following examples are explained below. s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride a-BPDA: 2,3,3',4'-biphenyltetracarboxylic dianhydride ODA: 4,4'-diaminodiphenyl ether PPD: p-phenylenediamine BAPP: 2,2'-bis[4-(4-aminophenoxy)phenyl]propane MDX: 4,4'-methylenebis(2,6-xylidine) NMP: N-methyl-2-pyrrolidone

[0045] Example 1 396 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 40.05 g (0.2 mol) of ODA was added thereto and stirred at 50°C for 1 hour to dissolve. 58.84 g (0.2 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0046] This polyimide precursor composition was applied onto a polyimide film with a thickness of 50 μm. The obtained sample was placed on a SUS plate that had been preheated to 380° C. and held for 1 minute to create an insulating coating layer with a thickness of approximately 25 μm. The time it took for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (heating rate: 15° C. / s). The state observation and property evaluation results for the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0047] Example 2 396 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 40.05 g (0.2 mol) of ODA was added thereto and stirred at 50° C. for 1 hour to dissolve. 47.08 g (0.16 mol) of s-BPDA and 11.77 g (0.04 mol) of a-BPDA were added to this solution and stirred at 50° C. for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0048] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0049] Comparative Example 1 396 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 40.05 g (0.2 mol) of ODA was added thereto and stirred at 50° C. for 1 hour to dissolve. 52.96 g (0.18 mol) of s-BPDA and 5.88 g (0.02 mol) of a-BPDA were added to this solution and stirred at 50° C. for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0050] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0051] Comparative Example 2 396 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 40.05 g (0.2 mol) of ODA was added thereto and stirred at 50°C for 1 hour to dissolve. 58.84 g (0.2 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0052] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0053] Example 3 386 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 25.95 g (0.24 mol) of PPD was added thereto and stirred at 50°C for 1 hour to dissolve. 70.61 g (0.24 mol) of a-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.2 mass% and a solution viscosity of 5.0 Pa s.

[0054] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0055] Example 4 386 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 25.95 g (0.24 mol) of PPD was added thereto and stirred at 50° C. for 1 hour to dissolve. 35.31 g (0.12 mol) of s-BPDA and 35.31 g (0.12 mol) of a-BPDA were added to this solution and stirred at 50° C. for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.2 mass% and a solution viscosity of 5.0 Pa s.

[0056] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0057] Comparative Example 3 386 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 25.95 g (0.24 mol) of PPD was added thereto and stirred at 50° C. for 1 hour to dissolve. 42.37 g (0.14 mol) of s-BPDA and 28.25 g (0.10 mol) of a-BPDA were added to this solution and stirred at 50° C. for 3 hours to obtain a polyimide precursor composition with a solid content of 18.2 mass% and a solution viscosity of 5.0 Pa s.

[0058] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0059] Comparative Example 4 386 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 25.95 g (0.24 mol) of PPD was added thereto and stirred at 50°C for 1 hour to dissolve. 70.61 g (0.24 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid concentration of 18.2 mass% and a solution viscosity of 5.0 Pa s.

[0060] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 1.

[0061] Example 5 395 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, and 57.47 g (0.14 mol) of BAPP was added thereto and stirred at 50°C for 1 hour to dissolve. 41.19 g (0.14 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solids concentration of 19.0 mass% and a solution viscosity of 5.0 Pa s.

[0062] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0063] Example 6 401 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, followed by 22.17 g (0.05 mol) of BAPP and 25.23 g (0.13 mol) of ODA, which were then stirred at 50°C for 1 hour to dissolve. 52.96 g (0.18 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solids concentration of 18.7 mass% and a solution viscosity of 5.0 Pa s.

[0064] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0065] Comparative Example 5 386 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, followed by the addition of 14.78 g (0.04 mol) of BAPP and 28.83 g (0.14 mol) of ODA, and the mixture was stirred at 50°C for 1 hour to dissolve. 52.96 g (0.18 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solids concentration of 18.7 mass% and a solution viscosity of 5.0 Pa s.

[0066] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0067] Example 7 393 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, to which 45.98 g (0.11 mol) of BAPP and 5.19 g (0.05 mol) of PPD were added and stirred at 50°C for 1 hour to dissolve. 47.08 g (0.16 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid content of 18.8 mass% and a solution viscosity of 5.0 Pa s.

[0068] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0069] Comparative Example 6 397 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, followed by 41.87 g (0.10 mol) of BAPP and 7.35 g (0.07 mol) of PPD, which were then stirred at 50°C for 1 hour to dissolve. 50.02 g (0.17 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solids concentration of 18.8 mass% and a solution viscosity of 5.0 Pa s.

[0070] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0071] Example 8 In a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, 404 g of NMP was added as a solvent, followed by 10.18 g (0.04 mol) of MDX and 32.04 g (0.16 mol) of ODA, which were then stirred at 50°C for 1 hour to dissolve. 58.84 g (0.2 mol) of s-BPDA was added to this solution, which was then stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid content of 18.6 mass% and a solution viscosity of 5.0 Pa s.

[0072] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0073] Comparative Example 7 400 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, 5.09 g (0.02 mol) of MDX and 36.04 g (0.18 mol) of ODA were added to the solution, and the mixture was stirred at 50°C for 1 hour to dissolve the mixture. 58.84 g (0.20 mol) of s-BPDA was added to the solution, and the mixture was stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid content of 18.6 mass% and a solution viscosity of 5.0 Pa s.

[0074] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0075] Comparative Example 8 392 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, to which 30.53 g (0.12 mol) of MDX and 8.65 g (0.08 mol) of PPD were added and dissolved by stirring at 50°C for 1 hour. 58.84 g (0.2 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid content of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0076] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0077] Comparative Example 9 399 g of NMP was added as a solvent to a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet tubes, followed by 26.71 g (0.11 mol) of MDX and 11.35 g (0.11 mol) of PPD, which were then stirred at 50°C for 1 hour to dissolve. 61.79 g (0.21 mol) of s-BPDA was added to this solution and stirred at 50°C for 3 hours to obtain a polyimide precursor composition with a solid content of 18.5 mass% and a solution viscosity of 5.0 Pa s.

[0078] Using this polyimide precursor composition, an insulating coating layer was produced in the same manner as in Example 1. The time required for the sample temperature to rise from 100° C. to 280° C. was 12 seconds (temperature rise rate: 15° C. / s). The results of observation of the state and evaluation of the properties of the obtained polyimide precursor composition and insulating coating layer are shown in Table 2.

[0079] [Table 1]

[0080] [Table 2]

Claims

1. A polyimide precursor composition comprising a polyamic acid and a solvent, The polyamic acid is a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride and a diamine component, and the water vapor permeability coefficient is 1.7 g mm / (m ２ The polyimide precursor composition does not contain a basic compound selected from the group consisting of imidazoles and amine compounds, and the diamine component is a compound represented by the following formula (1): 【Chemistry 1】 (wherein A is a direct bond or a bridging group; R １ ~R ４ represents a substituent selected from a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 6 carbon atoms, and a carboalkoxy group; R １ and R ２ At least one of R is not a hydrogen atom. ３ and R ４ At least one of is not a hydrogen atom.) A polyimide precursor composition for forming an electric wire insulating coating layer, which does not contain a compound represented by the following formula (1) in an amount of 0.5 to 40 mol %.

2. the tetracarboxylic acid component comprises 2,3,3',4'-biphenyltetracarboxylic dianhydride; 2. The polyimide precursor composition for forming an electric wire insulating coating layer according to claim 1, wherein the diamine component contains 50 to 100 mol % of paraphenylenediamine and 4,4'-diaminodiphenyl ether, or either one of them.

3. The tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2. The polyimide precursor composition for forming a wire insulating coating layer according to claim 1, wherein the diamine component comprises one or more diamines selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, and contains 30 to 100 mol % of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane.

4. The tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2. The polyimide precursor composition for forming a wire insulating coating layer according to claim 1, wherein the diamine component comprises one or more diamines selected from the group consisting of 4,4'-diaminodiphenyl ether and 4,4'-methylenebis(2,6-xylidine), and contains 20 to 100 mol % of 4,4'-methylenebis(2,6-xylidine).

5. The polyimide precursor composition for forming a wire insulating covering layer according to any one of claims 1 to 4, wherein the polyimide film is not cloudy when visually observed.

6. A method for producing an electric wire insulating coating layer, comprising a step of applying a polyimide precursor composition to a substrate, which is an electric wire, and baking the composition, The polyimide precursor composition contains a polyamic acid obtained from a tetracarboxylic acid component containing 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride and / or 2,3,3',4'-biphenyltetracarboxylic dianhydride and a diamine component, and does not contain a basic compound selected from the group consisting of imidazoles and amine compounds. When the polyamic acid is heat-treated under conditions of a temperature rise time from 100°C to 280°C of 12 seconds and a maximum heating temperature of 380°C, the water vapor permeability coefficient is 1.7 g mm / (m 2 ・It is possible to produce a polyimide film having a film thickness greater than 24 h. In the baking process, The time for heating the polyimide precursor composition is 10 to 180 seconds; The average heating rate from 100° C. to 280° C. is 5° C. / s or more; A method for producing a wire insulating coating layer, characterized in that the maximum heating temperature is 300 to 500°C.

7. the tetracarboxylic acid component comprises 2,3,3',4'-biphenyltetracarboxylic dianhydride; 7. The method for producing a wire insulating covering layer according to claim 6, wherein the diamine component contains 50 to 100 mol % of paraphenylenediamine and / or 4,4'-diaminodiphenyl ether.

8. The tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, 7. The method for producing a wire insulating coating layer according to claim 6, wherein the diamine component comprises one or more diamines selected from the group consisting of paraphenylenediamine, 4,4'-diaminodiphenyl ether, and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, and contains 30 to 100 mol % of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane.

9. The tetracarboxylic acid component contains 50 to 100 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride, The method for producing a wire insulating coating layer according to claim 6, wherein the diamine component comprises one or more diamines selected from the group consisting of 4,4'-diaminodiphenyl ether and 4,4'-methylenebis(2,6-xylidine), and contains 20 to 100 mol% of 4,4'-methylenebis(2,6-xylidine).

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