Polyamic acid-containing solution and method for producing a polyamic acid-containing solution

Abstract

The present invention relates to a method for producing a poly(amic acid)-containing liquid, in which a prepolymer-containing liquid, which contains an amic acid prepolymer, a diamine, and a tetracarboxylic acid dianhydride are used to obtain the poly(amic acid)-containing liquid.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for producing a polyamic acid-containing liquid, a polyamic acid-containing liquid, and methods for producing a polyimide, a molded body, and a printed circuit board.

Background Art

[0002] Polyimide is widely used in fields such as automobiles, electronic components, and displays because of its high heat resistance, chemical resistance, high mechanical properties, and low dielectric constant. For example, semi-aromatic polyimides having a structure derived from an aliphatic or alicyclic diamine and a structure derived from an aromatic tetracarboxylic dianhydride, or a structure derived from an aromatic diamine and an aliphatic or alicyclic acid dianhydride, are expected to be applied to high-frequency antennas, substrates such as FPCs (flexible printed circuit boards), and coil insulation coatings for inverter-driven motors with increasing high frequencies and high voltages.

[0003] Patent Document 1 discloses a solvent-insoluble polyimide film using a dimer diamine in an amount of more than 15 mol% and less than 50 mol% based on the total diamine component. Patent Document 1 also discloses that a polyamic acid solution can be obtained as an optically uniform solution by, for example, blending a polyamic acid solution in a nitrogen-containing polar solvent so that substantially equimolar amounts of a tetracarboxylic dianhydride and a diamine are present, and subjecting the mixture to a polymerization reaction at 10 to 70°C.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] This disclosure provides a method for easily producing a polyamic acid-containing liquid that can yield a polyimide exhibiting excellent dielectric properties. Furthermore, this disclosure provides a polyamic acid-containing liquid that can yield a polyimide exhibiting excellent dielectric properties and also exhibits excellent film-forming properties. In addition, this disclosure provides a method for manufacturing a polyimide, a molded article, and a printed circuit board exhibiting excellent dielectric properties. [Means for solving the problem]

[0006] Examples of embodiments are listed below. The present invention is not limited to the following embodiments. One embodiment relates to a method for producing a polyamic acid-containing liquid, which includes obtaining a polyamic acid-containing liquid using a prepolymer-containing liquid containing an amidic acid prepolymer including an aromatic diamine-derived structure and a tetracarboxylic dianhydride-derived structure, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride.

[0007] Another embodiment relates to a method for producing a polyamic acid-containing liquid, which includes a prepolymer-containing liquid containing an amidic acid prepolymer comprising a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a polyamic acid-containing liquid containing a polyamic acid using a diamine and a tetracarboxylic dianhydride.

[0008] Another embodiment comprises a polyamic acid containing structures derived from aliphatic or alicyclic diamines and structures derived from tetracarboxylic dianhydrides, and a solvent. This relates to a polyamic acid-containing solution that satisfies either or both of the following conditions (1) and (2). (1) The content of components derived from amines and carboxylic acid anhydrides is 20.0% by mass or more, and the turbidity is 2.5 NTU or less. (2) The content of the polyamic acid is 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent.

[0009] Another embodiment comprises a polyamic acid containing structures derived from aliphatic or alicyclic diamines and structures derived from tetracarboxylic dianhydrides, and a solvent. The present invention relates to a polyamic acid-containing solution that satisfies either or both of the following conditions (3) and (4). (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from the amine and carboxylic acid anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more. (4) The ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is 18.0% by mass or more.

[0010] Other embodiments relate to the polyamic acid-containing liquid used for insulating materials, heat-resistant insulating materials, or printed circuit boards. Several other embodiments relate to methods for manufacturing polyimides, molded articles, and printed circuit boards using the polyamic acid-containing solution described above. [Effects of the Invention]

[0011] This disclosure provides a method for easily producing a polyamic acid-containing liquid that can yield a polyimide exhibiting excellent dielectric properties. Furthermore, this disclosure provides a polyamic acid-containing liquid that can yield a polyimide exhibiting excellent dielectric properties and also exhibits excellent film-forming properties. Moreover, this disclosure provides a method for manufacturing a polyimide, a molded article, and a printed circuit board exhibiting excellent dielectric properties. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will now be described. The present invention is not limited to the following embodiments. Furthermore, the following embodiments can be implemented individually or in combination. Combinations of multiple embodiments are also included in the present invention.

[0013] In numerical ranges described stepwise within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, the upper or lower limits of numerical ranges described within this disclosure may be replaced with the values ​​shown in the examples. A numerical value may be selected from the upper and lower limits described stepwise within this disclosure to form a stepped numerical range. Also, the upper and lower limits described within this disclosure may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In this disclosure, each structure in the polymer may contain multiple types of that structure. When multiple types of structures exist in the polymer, the content or amount of each structure means the total content or amount of those multiple types of structures present in the polymer, unless otherwise specified. In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended function of that process is achieved. In this disclosure, the term "layer" includes not only layers that are formed over the entire region in which the layer exists, but also layers that are formed over only a portion of that region when the region in which the layer exists is observed.

[0014] <Method for producing a polyamic acid-containing solution> A method for producing a polyamic acid-containing solution includes obtaining a polyamic acid-containing solution using a prepolymer-containing solution containing an amidic acid prepolymer, a diamine, and a tetracarboxylic dianhydride.

[0015] In some embodiments, a method for producing a polyamic acid-containing solution includes obtaining a polyamic acid-containing solution using a prepolymer-containing solution containing an amidic acid prepolymer including structures derived from aromatic diamines and structures derived from tetracarboxylic dianhydrides, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride. In this disclosure, this production method may be referred to as "production method R".

[0016] In some other embodiments, a method for producing a polyamic acid-containing solution includes obtaining a polyamic acid-containing solution using a prepolymer-containing solution containing an amidoic acid prepolymer comprising structures derived from aliphatic or alicyclic diamines and structures derived from tetracarboxylic dianhydrides, a diamine, and a tetracarboxylic dianhydride. In this disclosure, this method may be referred to as "production method L".

[0017] Polyamic acids are typically synthesized by addition condensation, i.e., polymerization of diamines with tetracarboxylic dianhydrides. Polymerization of aromatic diamines with tetracarboxylic dianhydrides generally proceeds readily at room temperature. However, polymerization of diamines, including aliphatic or alicyclic diamines, with tetracarboxylic dianhydrides presents a problem of precipitate formation, hindering the reaction. Aliphatic or alicyclic diamines are considerably more basic than aromatic diamines. The precipitate is thought to contain a salt formed from unreacted aliphatic or alicyclic diamines exhibiting high basicity, and carboxylic acids (i.e., ring-opened carboxylic dianhydrides) produced during the addition condensation process, or polyamic acids having carboxyl groups obtained by addition condensation.

[0018] According to the present disclosure, even when the diamine contains an aliphatic or alicyclic diamine, the reaction can be advanced by a simple operation of using an amic acid prepolymer, a diamine, and a tetracarboxylic dianhydride to suppress salt formation, dissolve the formed salt, or both. Thereby, a polyamic acid-containing solution containing a polyamic acid containing a structure derived from an aliphatic or alicyclic diamine can be easily produced. Further, according to some embodiments, a polyamic acid-containing solution containing a polyamic acid at a high concentration can be produced in a short time.

[0019] [Production method R] Production method R includes obtaining a polyamic acid-containing solution containing a polyamic acid by using a prepolymer-containing solution containing an amic acid prepolymer containing a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride (in the present disclosure, this may be referred to as "step R2"). Production method R can further include preparing a prepolymer-containing solution containing an amic acid prepolymer containing a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride (in the present disclosure, this may be referred to as "step R1"). In the present disclosure, the tetracarboxylic dianhydride may be referred to as "acid dianhydride". In the present disclosure, an amic acid prepolymer containing a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride may be referred to as an "aromatic prepolymer", and a prepolymer-containing solution containing an aromatic prepolymer may be referred to as an "aromatic prepolymer-containing solution". Production method R can include any steps other than step R1 and step R2.

[0020] According to production method R, even when an aliphatic or alicyclic diamine is used, the polymerization can proceed. One reason for this is speculated as follows. In production method R, an aromatic prepolymer, an aliphatic or alicyclic diamine, and an acid dianhydride are reacted to obtain a polyamic acid. The aliphatic or alicyclic diamine forms salts with the aromatic prepolymer and the acid dianhydride, respectively. When the composition of the polyamic acid to be obtained is the same, in production method R, since a salt of the aliphatic or alicyclic diamine and the aromatic prepolymer is formed, compared with the case of obtaining a polyamic acid using an aromatic diamine and an aliphatic or alicyclic diamine and an acid dianhydride, the amount of the salt of the aliphatic or alicyclic diamine and the acid dianhydride is reduced. Due to the influence of the structure, the salt of the aromatic prepolymer is more soluble than the salt of the acid dianhydride. In production method R, a salt of the aromatic prepolymer that is easily soluble is formed, and the formation of a salt of the acid dianhydride that is difficult to dissolve is suppressed. That is, production method R is a method of promoting the dissolution of the entire salt by reducing the poorly soluble salt and including the easily soluble salt, and thereby the polymerization reaction can proceed. However, the present invention is not limited by this speculation.

[0021] In step R1, an aromatic prepolymer-containing solution is prepared. In some embodiments, step R1 may be to prepare an aromatic prepolymer-containing solution using a prepolymer-containing solution containing an amic acid prepolymer containing a structure derived from a previously prepared aromatic diamine and a structure derived from an acid dianhydride (step R1-s). Alternatively, in some embodiments, step R1 may be to obtain an aromatic prepolymer-containing solution containing an aromatic prepolymer using an aromatic diamine, an acid dianhydride, and a solvent (step R1-i).

[0022] In step R2, a polyamic acid-containing solution is obtained using an aromatic prepolymer-containing solution, an aliphatic or alicyclic diamine, and an acidic dianhydride. An aromatic diamine may be used further. For example, step R2 may be obtained by adding an aliphatic or alicyclic diamine and an acidic dianhydride to the aromatic prepolymer-containing solution to obtain a polyamic acid-containing solution containing polyamic acid (step R2-a). An aliphatic or alicyclic diamine, an acidic dianhydride, and an aromatic diamine may be added to the aromatic prepolymer-containing solution. In a method in which only one of an aliphatic or alicyclic diamine or an acidic dianhydride is added to the aromatic prepolymer-containing solution, the polymerization reaction is difficult to proceed because it is easily affected by the water present in the reaction system or because poorly soluble salts are easily formed.

[0023] Examples of embodiments of manufacturing method R include manufacturing method Rs, which includes steps R1-s and R2-a, and manufacturing method Ri, which includes steps R1-i and R2-a. In manufacturing method Ri, preferably, step R2-a is performed immediately following step R1-i.

[0024] In step R1-s, for example, a prepolymer-containing solution containing an amide acid prepolymer containing a pre-prepared aromatic diamine-derived structure and an acid dianhydride-derived structure can be used as is in step R2. Alternatively, in step R1-s, for example, a pre-prepared prepolymer-containing solution can be diluted or concentrated as needed to adjust the concentration and then used in step R2. The pre-prepared prepolymer-containing solution used in step R1-s may be, for example, a pre-prepared prepolymer-containing solution or a commercially available prepolymer-containing solution. The prepolymer-containing solution can be prepared by known methods for producing polyamic acid solutions, the method for producing polyamic acid-containing solutions according to this disclosure, and the like.

[0025] Step R1-i may be, for example, the following method: First, an aromatic diamine is dissolved in a solvent to prepare an aromatic diamine solution. Next, an acidic dianhydride is added to the aromatic diamine solution and stirred. The stirring time is, for example, 5 minutes to 5 hours, 10 minutes to 3 hours, or 30 minutes to 2 hours. The stirring temperature is, for example, 10 to 50°C, 15 to 40°C, or 20 to 35°C.

[0026] The acidic dianhydride may be added to the aromatic diamine solution in its entirety at once, or it may be added to the aromatic diamine solution in two or more separate additions. The number of additions may be, for example, 10 or fewer, 7 or fewer, or 4 or fewer. The interval between additions may be, for example, 5 minutes or more, or 10 minutes or more. The interval between additions may be, for example, 120 minutes or less, 60 minutes or less, 30 minutes or less, or 15 minutes or less.

[0027] Aromatic diamines have low basicity, making it difficult for them to form salts with acidic dianhydrides. Therefore, in step R1-i, an aromatic prepolymer-containing solution with a high concentration of aromatic prepolymers can be easily prepared.

[0028] Step R2-a may include, for example, the following method: First, an aliphatic or alicyclic diamine is dissolved in a solvent to prepare an aliphatic or alicyclic diamine solution. Next, the aliphatic or alicyclic diamine solution and an acidic dianhydride are added to the aromatic prepolymer-containing liquid prepared in step R1 and stirred. The stirring time is, for example, 10 minutes or more, 1 hour or more, or 3 hours or more. The stirring time is, for example, 72 hours or less, 48 ​​hours or less, 24 hours or less, 12 hours or less, or 5 hours or less. The stirring temperature is, for example, 10-50°C, 15-40°C, or 20-35°C. If a stirring bar is used for stirring, the rotation speed is, for example, 50-2,000 min⁻¹. -1 200-1,000 min -1 , or 300-800 min -1 That is the case.

[0029] Depending on the amount of aromatic prepolymer and the aliphatic or alicyclic diamine and acidic dianhydride added, as well as the method of addition, salt usually precipitates upon addition. The stirring time is preferably longer than the time required for the salt to dissolve. On the other hand, from the viewpoint of manufacturing efficiency, a shorter stirring time is preferable. According to manufacturing method R, since the salt can be dissolved in a short time, a polyamic acid-containing solution can be produced efficiently. The salt can be dissolved in a short time if the stirring temperature is high. Therefore, stirring may be performed while heating. On the other hand, from the viewpoint of easy production, stirring without heating is preferable. According to manufacturing method R, since the salt can be dissolved in a short time without heating, polyamic acid can be produced efficiently. The salt can be dissolved in a short time if an additive that can dissolve salts, such as acetic acid, is used. Therefore, stirring may be performed in the presence of an additive that can dissolve salts. On the other hand, from the viewpoint of easy production, stirring without using an additive is preferable. According to manufacturing method R, since the salt can be dissolved in a short time without using an additive, polyamic acid can be produced efficiently.

[0030] The aliphatic or alicyclic diamine solution and the acidic dianhydride may be added simultaneously to the aromatic prepolymer-containing solution, or they may be added separately. The aliphatic or alicyclic diamine solution, the acidic dianhydride, or both the aliphatic or alicyclic diamine solution and the acidic dianhydride may be added to the aromatic prepolymer-containing solution in their entirety at once, or they may be added in two or more separate additions. If added in two or more additions, the number of additions may be, for example, 10 or fewer, 7 or fewer, or 4 or fewer. The interval between additions may be, for example, 5 minutes or more, or 10 minutes or more. Alternatively, there may be no particular restriction on the number of additions when added in two or more additions, and the solution may be added dropwise over a predetermined time or the solid may be added in small amounts. The predetermined time may be, for example, 10 to 60 minutes. When adding both an aliphatic or alicyclic diamine solution and an acidic dianhydride to an aromatic prepolymer-containing solution in two or more separate additions, the number of additions may be the same or different.

[0031] Aliphatic or alicyclic diamines and aromatic diamines may be added to the aromatic prepolymer-containing solution. In this case, the aliphatic or alicyclic diamines and aromatic diamines may be added to the aromatic prepolymer-containing solution simultaneously or separately. The aromatic diamines may be added to the aromatic prepolymer-containing solution in their entirety at once, or they may be added to the aromatic prepolymer-containing solution in two or more separate additions.

[0032] When steps R1-i and R2-a are performed consecutively, it is preferable to start adding at least one of the aliphatic or alicyclic diamine solution and the acidic dianhydride while stirring is continuing in step R1-i, or within, for example, 60 minutes after stopping stirring. When steps R1-i and R2-a are performed consecutively, the aliphatic or alicyclic diamine solution and the acidic dianhydride may be added to the container in which the aromatic prepolymer-containing liquid was obtained in step R1-i and stirred.

[0033] The aromatic prepolymer may contain any structure other than those derived from aromatic diamines and acid dianhydrides. For example, the aromatic prepolymer may contain any diamine-derived structure, such as those derived from aliphatic or alicyclic diamines. The content of the aromatic diamine-derived structure is, for example, more than 50% by mass, 70% or more by mass, 90% or more by mass, or 100% by mass, based on the total mass of all diamine-derived structures.

[0034] The mass-average molecular weight of the aromatic prepolymer is preferably 500 to 80,000, more preferably 1,000 to 50,000, and even more preferably 5,000 to 30,000. The mass-average molecular weight may be 20,000 or less, or 10,000 or less. When the mass-average molecular weight is 500 or more, the salt formed by the aromatic prepolymer and the aliphatic or alicyclic diamine tends to have low crystallinity and be easily soluble. When the mass-average molecular weight is 80,000 or less, it is possible to prevent the viscosity from becoming too high, the miscibility with the acidic dianhydride and the aliphatic or alicyclic diamine is good, and the dissolution rate of the salt tends to be increased. In this disclosure, the mass-average molecular weight can be determined by measuring it by gel permeation chromatography (GPC) and converting it using a calibration curve for standard polystyrene. Specifically, the mass-average molecular weight can be measured by the method described in the examples.

[0035] From the viewpoint of preventing the viscosity from becoming too high, the aromatic prepolymer content in the aromatic prepolymer-containing liquid is, for example, 30.0% by mass or less, 20.0% by mass or less, 12.0% by mass or less, or 8.0% by mass or less, based on the mass of the aromatic prepolymer-containing liquid. From the viewpoint of dissolving the salt in a short time, the aromatic prepolymer content is, for example, 3.0% by mass or more, 5.0% by mass or more, or 10.0% by mass or more, based on the mass of the aromatic prepolymer-containing liquid.

[0036] The mass ratio of the aromatic prepolymer used in manufacturing method R is, from the viewpoint of dissolving the salt in a short time, for example, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, 30.0% by mass or more, or 40.0% by mass or more, relative to the mass of the obtained polyamic acid. The mass ratio of the aromatic prepolymer is, considering the amount of aliphatic or alicyclic diamine and acidic dianhydride used, for example, 70.0% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, or 30% by mass or less, relative to the mass of the polyamic acid.

[0037] In particular, when obtaining a polyamic acid-containing solution with a high polyamic acid content, the aromatic prepolymer content in the aromatic prepolymer-containing solution is, for example, 15.0% by mass or more, 18.0% by mass or more, or 20.0% by mass or more, based on the mass of the aromatic prepolymer-containing solution. The aromatic prepolymer content is, for example, 30.0% by mass or less, or 25.0% by mass or less, based on the mass of the aromatic prepolymer-containing solution.

[0038] In particular, when obtaining a polyamic acid-containing solution with a high polyamic acid content, the mass ratio of the aromatic prepolymer used in production method R is, for example, 50.0% by mass or more, 65.0% by mass or more, or 65.0% by mass or more, relative to the mass of the obtained polyamic acid. The mass ratio of the aromatic prepolymer is, for example, 90.0% by mass or less, 80% by mass or less, or 75.0% by mass or less, relative to the mass of the polyamic acid, taking into account the amount of aliphatic or alicyclic diamines and acidic dianhydrides used.

[0039] The polyamic acid-containing solution obtained by manufacturing method R typically contains polyamic acid and a solvent. The polyamic acid content is not particularly limited and can be set to an appropriate content depending on the application of the polyamic acid-containing solution. Manufacturing method R makes it possible to produce a polyamic acid-containing solution with a high polyamic acid content. The polyamic acid content may be, for example, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, or 25.0% by mass or more, based on the total mass of the polyamic acid and the solvent. The polyamic acid content may be, for example, 50.0% by mass or less, 40.0% by mass or less, or 30.0% by mass or less, based on the total mass of the polyamic acid and the solvent.

[0040] The polyamic acid obtained by manufacturing method R contains at least a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from an acidic dianhydride. The polyamic acid may further contain any other structures. In manufacturing method R, monomers such as diamines and acidic dianhydrides can be selected and used depending on the structure contained in the desired polyamic acid. Preferred embodiments (e.g., types, content, etc.) of the polyamic acid-containing solution and the polyamic acid contained therein, as well as amines such as diamines, acids such as acidic dianhydrides, and solvents that can be used in manufacturing method R will be described later.

[0041] [Manufacturing method L] The manufacturing method L includes obtaining a polyamic acid-containing liquid containing a polyamic acid using a prepolymer-containing liquid containing an amidic acid prepolymer that includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride, and a diamine and an acid dianhydride (in this disclosure, this may be referred to as "step L2"). The manufacturing method L may further include preparing a prepolymer-containing liquid containing an amidic acid prepolymer that includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride (in this disclosure, this may be referred to as "step L1"). In this disclosure, the amidic acid prepolymer that includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride may be referred to as an "aliphatic or alicyclic prepolymer," and the prepolymer-containing liquid containing an aliphatic or alicyclic prepolymer may be referred to as an "aliphatic or alicyclic prepolymer-containing liquid." The manufacturing method L may include any steps other than steps L1 and L2.

[0042] According to manufacturing method L, if an aliphatic or alicyclic diamine is not used, polymerization can proceed because no salt of the aliphatic or alicyclic diamine is formed. Alternatively, according to manufacturing method L, polymerization can proceed even when an aliphatic or alicyclic diamine is used. One reason for this is presumed to be as follows: In manufacturing method L, when the diamine contains an aliphatic or alicyclic diamine, polyamic acid is obtained by reacting the aliphatic or alicyclic prepolymer with the aliphatic or alicyclic diamine and the acidic dianhydride. The aliphatic or alicyclic diamine forms salts with the aliphatic or alicyclic prepolymer and the acidic dianhydride, respectively. If the composition of the polyamic acid to be obtained is the same, in manufacturing method L, a salt is formed between the aliphatic or alicyclic diamine and the aliphatic or alicyclic prepolymer, so the amount of salt between the aliphatic or alicyclic diamine and the acidic dianhydride is less compared to when polyamic acid is obtained using the aliphatic or alicyclic diamine and the acidic dianhydride. Salts of aliphatic or alicyclic prepolymers dissolve more easily than salts of acid dianhydrides due to their structure. In manufacturing method L, easily soluble salts of aliphatic or alicyclic prepolymers are formed, while the formation of poorly soluble salts of acid dianhydrides is suppressed. In other words, manufacturing method L, when the diamine contains an aliphatic or alicyclic diamine, is a method that promotes the dissolution of the entire salt by reducing the amount of poorly soluble salts and including the amount of easily soluble salts, thereby allowing the polymerization reaction to proceed. However, the present invention is not limited by this assumption.

[0043] In step L1, an aliphatic or alicyclic prepolymer-containing solution is prepared. In some embodiments, step L1 may be the preparation of an aliphatic or alicyclic prepolymer-containing solution using a prepolymer-containing solution containing an amidic acid prepolymer that includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride (step L1-s). Alternatively, in some embodiments, step L1 may be the preparation of an aliphatic or alicyclic prepolymer-containing solution containing an aliphatic or alicyclic prepolymer using an aliphatic or alicyclic diamine, an acid dianhydride, and a solvent (step L1-i).

[0044] In step L2, a polyamic acid-containing solution is obtained using an aliphatic or alicyclic prepolymer-containing solution, a diamine, and an acidic dianhydride. The diamine may include either or both aliphatic or alicyclic diamines and aromatic diamines. For example, step L2 may be obtained by adding a diamine and an acidic dianhydride to an aliphatic or alicyclic prepolymer-containing solution to obtain a polyamic acid-containing solution containing polyamic acid (step L2-a). In a method in which only one of the diamine or acidic dianhydride is added to an aliphatic or alicyclic prepolymer-containing solution, the polymerization reaction is difficult to proceed because it is easily affected by the water present in the reaction system or because poorly soluble salts are easily formed.

[0045] Examples of embodiments of manufacturing method L include manufacturing method Ls, which includes steps L1-s and L2-a, and manufacturing method Li, which includes steps L1-i and L2-a. In manufacturing method Li, preferably, step L2-a is performed immediately following step L1-i.

[0046] The descriptions of steps R1-s, R1-i, and R2-a in manufacturing method R can be applied to steps L1-s, L1-i, and L2-a in manufacturing method L, with necessary modifications. For example, the methods, times, temperatures, etc., in steps L1-s, L1-i, and R2-a can be the same as those given in steps R1-s, R1-i, and R2-a.

[0047] However, in step L1-i, since aliphatic or alicyclic diamines tend to form salts with acidic dianhydrides, the amounts of aliphatic or alicyclic diamine, acidic dianhydride, and solvent used may be adjusted to prevent salt precipitation and keep the concentration of the resulting aliphatic or alicyclic prepolymer-containing solution low. The aliphatic or alicyclic prepolymer content is particularly preferably 15.0% by mass or less, based on the mass of the aliphatic or alicyclic prepolymer-containing solution.

[0048] In step L2-a, when adding an alicyclic or aliphatic diamine and an aromatic diamine as diamines to an aliphatic or alicyclic prepolymer-containing liquid, it is preferable to add an alicyclic or aliphatic diamine solution and a solid aromatic diamine to the aliphatic or alicyclic prepolymer-containing liquid, or to add a solution containing an alicyclic or aliphatic diamine and an aromatic diamine.

[0049] Aliphatic or alicyclic prepolymers may contain any structures other than those derived from aliphatic or alicyclic diamines and acid dianhydrides. For example, an aliphatic or alicyclic prepolymer may contain any diamine-derived structures, such as those derived from aromatic diamines. The content of aliphatic or alicyclic diamine-derived structures is, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass, based on the mass of all diamine-derived structures.

[0050] The mass-average molecular weight of the aliphatic or alicyclic prepolymer is preferably 500 to 80,000, more preferably 1,000 to 50,000, and even more preferably 5,000 to 30,000. The mass-average molecular weight may be 10,000 or more, 20,000 or more, or 30,000 or more. When the mass-average molecular weight is 500 or more, the salt formed by the aliphatic or alicyclic prepolymer and the aliphatic or alicyclic diamine tends to have low crystallinity and be easily soluble. When the mass-average molecular weight is 80,000 or less, it is possible to prevent the viscosity from becoming too high, improve miscibility with the acidic dianhydride and diamine, and tend to increase the dissolution rate of the salt.

[0051] From the viewpoint of dissolving the salt in a short time, the content of the aliphatic or alicyclic prepolymer in the aliphatic or alicyclic prepolymer-containing solution is, for example, 15.0% by mass or less, 13.0% by mass or less, 10.0% by mass or less, or 8.0% by mass or less, based on the mass of the aliphatic or alicyclic prepolymer-containing solution. From the viewpoint of dissolving the salt in a short time, the content of the aliphatic or alicyclic prepolymer is, for example, 3.0% by mass or more, 5.0% by mass or more, or 10.0% by mass or more, based on the mass of the aliphatic or alicyclic prepolymer-containing solution.

[0052] The mass ratio of the aliphatic or alicyclic prepolymer used in manufacturing method L is, from the viewpoint of dissolving the salt in a short time, for example, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, 30.0% by mass or more, or 40.0% by mass or more, relative to the mass of the obtained polyamic acid. The mass ratio of the aliphatic or alicyclic prepolymer is, considering the amount of diamine and acidic dianhydride used, for example, 70.0% by mass or less, 60% by mass or less, 50.0% by mass or less, 40.0% by mass or less, or 30.0% by mass or less, relative to the mass of the polyamic acid.

[0053] The polyamic acid-containing solution obtained by manufacturing method L typically contains polyamic acid and a solvent. The polyamic acid content is not particularly limited and can be set to an appropriate content depending on the application of the polyamic acid-containing solution. Manufacturing method L allows for the production of polyamic acid-containing solutions containing high concentrations of polyamic acid. The polyamic acid content may be, for example, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, or 25.0% by mass or more, based on the mass of the polyamic acid-containing solution. The polyamic acid content may also be, for example, 50.0% by mass or less, 40.0% by mass or less, or 30.0% by mass or less, based on the mass of the polyamic acid-containing solution.

[0054] The polyamic acid obtained by manufacturing method L contains at least a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acidic dianhydride. The polyamic acid may further contain any other structure. For example, the polyamic acid may contain any diamine-derived structure, such as a structure derived from an aromatic diamine. In manufacturing method L, monomers such as diamines and acidic dianhydrides may be selected and used depending on the structure contained in the desired polyamic acid. Preferred embodiments (e.g., types, content, etc.) of the polyamic acid-containing solution and the polyamic acid contained therein, as well as amines such as diamines, acids such as acidic dianhydrides, and solvents that can be used in manufacturing method L will be described later.

[0055] <Polyamic acid-containing solution> The polyamic acid-containing solution contains a polyamic acid and a solvent, including structures derived from aliphatic or alicyclic diamines and structures derived from acid dianhydrides. The polyamic acid may contain any structures other than those derived from aliphatic or alicyclic diamines, such as structures derived from amines other than those derived from acid dianhydrides, and structures derived from carboxylic acid anhydrides other than those derived from acid dianhydrides. The polyamic acid may further contain diamine-derived structures such as those derived from aromatic diamines. The acid dianhydride-derived structures preferably include structures derived from pyromellitic dianhydrides.

[0056] A high polyamic acid content is preferable in the polyamic acid-containing solution. A high polyamic acid content reduces the amount of solvent that volatilizes when using the polyamic acid-containing solution to manufacture molded articles, such as films, making it easier to obtain films with more uniform in-plane film thickness. A high polyamic acid content also increases the viscosity of the polyamic acid-containing solution, allowing for the production of films with thicker film thicknesses depending on the application.

[0057] In some embodiments, the content of components derived from amines and carboxylic acid anhydrides in the polyamic acid-containing solution is, for example, 20.0% by mass or more, based on the mass of the polyamic acid-containing solution. In some embodiments, the ratio of the mass of components derived from amines and carboxylic acid anhydrides obtained by heating the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is, for example, 18.0% by mass or more. When one or both of these content and / or ratios are large, a polyamic acid-containing solution with high viscosity tends to be obtained.

[0058] Examples of components derived from amines and carboxylic acid anhydrides (hereinafter sometimes referred to as "monomer-derived components") include polyamic acids, salts of aliphatic or alicyclic diamines with carboxylic acids, salts of aliphatic or alicyclic diamines with amide acid prepolymers, and polyimides. The monomer-derived components include at least one selected from these.

[0059] In some embodiments, the polyamic acid content in the polyamic acid-containing solution is, for example, 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent. In some embodiments, the ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is, for example, 18.0% by mass or more. When one or both of these content and / or ratios are high, good film-forming properties tend to be obtained.

[0060] Depending on the method of producing the polyamic acid-containing liquid, precipitates such as salts derived from monomers may be formed during the manufacturing process. If the precipitates do not dissolve, they will remain as solids in the polyamic acid-containing liquid. It is preferable that the polyamic acid-containing liquid does not contain solids, or if it contains solids, the content is small. When the polyamic acid-containing liquid does not contain solids or has a small content of solids, it is easier to obtain a uniform film with excellent surface flatness when using the polyamic acid-containing liquid to produce a molded article, such as a film.

[0061] In some embodiments, the turbidity of the polyamic acid-containing solution is, for example, 2.5 NTU (Nephelometric Turbidity Unit) or less. Lower turbidity tends to result in better film formation. Generally, a higher solid content in the polyamic acid-containing solution leads to higher turbidity.

[0062] In a preferred embodiment, the polyamic acid-containing solution contains a polyamic acid having structures derived from aliphatic or alicyclic diamines and structures derived from acidic dianhydrides, and a solvent, satisfying at least one of the following (1) to (4). For example, the polyamic acid-containing solution satisfies either or both of the following (1) and (2), or either or both of the following (3) or (4). (1) The content of components derived from amines and carboxylic acid anhydrides is 20.0% by mass or more, and the turbidity is 2.5 NTU or less. (2) The polyamic acid content is 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent. (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of components derived from amines and carboxylic acid anhydrides obtained by heating the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is 18.0% by mass or more. (4) The ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is 18.0% by mass or more.

[0063] The content of monomer-derived components in the polyamic acid-containing solution is preferably 20.0% by mass or more, 20.1% by mass or more, 20.2% by mass or more, 20.5% by mass or more, 21.0% by mass or more, 23.0% by mass or more, 25.0% by mass or more, or 25.1% by mass or more, based on the mass of the polyamic acid-containing solution. There is no particular upper limit to the content of monomer-derived components in the polyamic acid. The content of monomer-derived components is, for example, 50.0% by mass or less, 40.0% by mass or less, 30.0% by mass or less, 28.0% by mass or less, or 26.0% by mass or less, based on the mass of the polyamic acid-containing solution.

[0064] The ratio of monomer-derived components obtained by heating the polyamic acid-containing solution is preferably 18.0% by mass or more, 18.3% by mass or more, 18.5% by mass or more, 19.0% by mass or more, 20.0% by mass or more, 22.0% by mass or more, 22.5% by mass or more, 23.0% by mass or more, or 23.5% by mass or more, based on the mass of the polyamic acid-containing solution. There is no particular upper limit to the ratio of monomer-derived components in the polyamic acid. The ratio of monomer-derived components is, for example, 48.0% by mass or less, 38.0% by mass or less, 28.0% by mass or less, 26.0% by mass or less, or 24.0% by mass or less, based on the mass of the polyamic acid-containing solution.

[0065] The content and ratio of monomer-derived components can be adjusted by changing the amounts of diamine, acidic dianhydride, and solvent used in the preparation of the polyamic acid-containing solution. The content and ratio of components derived from amines and carboxylic acid anhydrides can be measured by the method described in the examples. The formula for correcting the water content may be used by appropriately changing the type of monomer and the average molecular weight.

[0066] The polyamic acid content may be, preferably, 20.0% by mass or more, 20.1% by mass or more, 20.2% by mass or more, 20.5% by mass or more, 21.0% by mass or more, 23.0% by mass or more, 25.0% by mass or more, or 25.1% by mass or more, based on the mass of the polyamic acid-containing solution. There is no particular upper limit to the polyamic acid content. The polyamic acid content may be, for example, 50.0% by mass or less, 40.0% by mass or less, 30.0% by mass or less, 28.0% by mass or less, or 26.0% by mass or less, based on the mass of the polyamic acid-containing solution.

[0067] The ratio of polyimide obtained by heating the filtrate of the polyamic acid-containing liquid is preferably 18.0% by mass or more, 18.3% by mass or more, 18.5% by mass or more, 19.0% by mass or more, 20.0% by mass or more, 22.0% by mass or more, 22.5% by mass or more, 23.0% by mass or more, or 23.5% by mass or more, based on the mass of the polyamic acid-containing liquid. There is no particular upper limit to the ratio of polyimide. The ratio of polyimide is, for example, 48.0% by mass or less, 38.0% by mass or less, 28.0% by mass or less, 26.0% by mass or less, or 24.0% by mass or less, based on the mass of the polyamic acid-containing liquid.

[0068] A polyamic acid-containing solution with a high polyamic acid content or a high polyimide ratio can be easily produced, for example, by the manufacturing method of the embodiment described above. The polyamic acid content and polyimide ratio can be measured using the filtrate obtained by filtering the polyamic acid-containing solution to remove solids such as salts derived from monomers. A 150-mesh stainless steel filter can be used for filtration. Specifically, the polyamic acid content and polyimide ratio can be measured by the method described in the examples. The calculation formula for correcting the water content can be used by appropriately changing the type of monomer and the average molecular weight.

[0069] The polyamic acid content and polyimide ratio may be the content or ratio at the temperature at which the polyamic acid-containing solution is actually used, respectively. Alternatively, the temperature of the polyamic acid-containing solution when determining these content and ratio may differ from the temperature at which the polyamic acid-containing solution is actually used. These content and ratio may be, for example, the content or ratio at a temperature of 20 to 35°C of the polyamic acid-containing solution, preferably at a temperature of 25°C. In this case, the polyamic acid-containing solution can be filtered at a temperature of 20 to 35°C (preferably 25°C), and the content or ratio can be measured using the resulting filtrate.

[0070] The turbidity of the polyamic acid-containing solution is preferably 2.5 NTU or less, 2.0 NTU or less, 1.5 NTU or less, 1.0 NTU or less, 0.5 NTU or less, or 0 NTU. In this disclosure, turbidity is the turbidity based on a formazin standard solution measured by a transmitted scattering light method. Specifically, turbidity can be measured by the method described in the examples. Generally, the lower the turbidity, the lower the content of solids such as salts. The turbidity may be the turbidity at the temperature when the polyamic acid-containing solution is actually used. Alternatively, the temperature of the polyamic acid-containing solution when determining the turbidity may be different from the temperature when the polyamic acid-containing solution is actually used. For example, the turbidity may be the turbidity when the temperature of the polyamic acid-containing solution is any of 20 to 35°C, and preferably the turbidity when the temperature of the polyamic acid-containing solution is 25°C.

[0071] The viscosity (ηinh) of the polyamic acid-containing solution is preferably 0.3 dL / g or higher, more preferably 0.5 dL / g or higher, and even more preferably 0.6 dL / g or higher. The viscosity of the polyamic acid-containing solution is, for example, 1.5 dL / g or less, 1.3 dL / g or less, or 1.0 dL / g or less. The viscosity of the polyamic acid-containing solution is the viscosity measured at 30°C using an Ostwald viscometer. The viscosity can be specifically measured by the method described in the examples.

[0072] The mass-average molecular weight of the polyamic acid is preferably 5,000 to 130,000, more preferably 10,000 to 120,000, even more preferably 15,000 to 110,000, and particularly preferably more than 15,000 and 100,000 or less. When the mass-average molecular weight is within the above range, good film-forming properties tend to be obtained.

[0073] In polyamic acid, the content of structures derived from aliphatic or alicyclic diamines is preferably 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid, for example, 30% by mass or more, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 100% by mass. When it is 20% by mass or more, excellent dielectric properties tend to be obtained. The content of structures derived from aliphatic or alicyclic diamines may be, for example, 80% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total mass of all diamine-derived structures contained in the polyamic acid.

[0074] In polyamic acid, the content of structures derived from aromatic diamines is preferably 80% by mass or less, based on the total mass of all diamine-derived structures contained in the polyamic acid, for example, 70% by mass or less, 50% by mass or less, 30% by mass or less, 20% by mass or less, or 0% by mass. If the polyamic acid contains structures derived from aromatic diamines, the content of structures derived from aromatic diamines may be 20% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid, from the viewpoint of mechanical strength.

[0075] In polyamic acid, the content of structures derived from pyromellitic dianhydride is preferably 50% by mass or more, based on the total mass of all dianhydride-derived structures contained in the polyamic acid, for example, 70% by mass or more, or 85% by mass or more, or 100% by mass.

[0076] In polyamic acid, it is preferable that the content of structures derived from aliphatic or alicyclic diamines is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid, and the content of structures derived from acidic dianhydrides is 50% by mass or more, based on the total mass of all tetracarboxylic dianhydride-derived structures contained in the polyamic acid. The molar ratio of diamine-derived structures to acidic dianhydride-derived structures is, for example, 1.00:0.90 to 1.00:1.10, and preferably 1.00:0.95 to 1.00:1.05.

[0077] Examples of structures derived from diamines and acidic dianhydrides that polyamic acids can contain will be described later. Of the aliphatic or alicyclic diamine-derived structures, those derived from alicyclic diamines are preferable, and those derived from dimer amines are more preferable. When a polyamic acid contains a dimer amine-derived structure, the dielectric constant and dielectric loss tangent of the polyimide can be reduced. Polyimides with low dielectric constant and dielectric loss tangent can suppress transmission loss, making them suitable for applications such as substrates for FPCs and high-frequency antennas.

[0078] The polyamic acid-containing solution contains a solvent. The polyamic acid-containing solution may contain any components other than polyamic acid and the solvent. Examples of solvents that the polyamic acid-containing solution may contain will be described later. The solvent may be a polar organic solvent, and it is preferable that it contains an amide-based solvent containing an amide bond.

[0079] The method for producing the polyamic acid-containing solution is not particularly limited, but the production method of the above embodiment can be preferably used.

[0080] <Diamine> The diamines that can be used in the method for producing the polyamic acid-containing solution of the above embodiment, and the diamines in the "diamine-derived structural units" contained in the polyamic acid-containing solution of the above embodiment, may include aromatic diamines, aliphatic or alicyclic diamines, or both.

[0081] In this disclosure, an aromatic diamine may be a diamine having at least one aromatic ring and two amino groups bonded to at least one aromatic ring. If an aromatic diamine has two or more aromatic rings, the two or more aromatic rings may be identical to each other or different to each other. If an aromatic diamine has two or more aromatic rings, the two amino groups may be bonded to one aromatic ring, or the two amino groups may be bonded to different aromatic rings. An aromatic diamine may further have at least one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups.

[0082] In this disclosure, an aliphatic or alicyclic diamine may be a diamine having at least one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups, and two amino groups, and not being an aromatic diamine. The aliphatic or alicyclic diamine may further have at least one aromatic ring. At least one of the two amino groups is bonded to the aliphatic hydrocarbon group or alicyclic hydrocarbon group. Both of the two amino groups may be bonded to the aliphatic hydrocarbon group or alicyclic hydrocarbon group, or only one of the two amino groups may be bonded to the aliphatic or alicyclic diamine. If the aliphatic or alicyclic diamine has two or more groups selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups, the two or more groups may be identical to each other or different to each other. When an aliphatic or alicyclic diamine has two or more groups selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups, the two amino groups may be bonded to one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups, or the two amino groups may each be bonded to different groups selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups. Amino groups bonded to aliphatic or alicyclic hydrocarbon groups are more basic than amino groups bonded to aromatic rings and therefore more likely to form salts with carboxylic acids.

[0083] Examples of aromatic diamines include 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 4,4'-(biphenyl-2,5-diylbisoxy)bisaniline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, and bis(4-(4-aminophenoxy)phenyl)sulfon 4,4'-Diamino-3,3'-Diamino-2,2'-Diamino-2,3'-Diamino-3,3'-Dihydroxybiphenyl, 4,4 Nodiphenyl sulfide, N-(4-aminophenoxy)-4-aminobenzamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, bis(3-aminophenyl)sulfone, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether, 5-trifluoromethyl-1,3-benzenediamine, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis Examples of diamines having an aromatic hydrocarbon group or an aromatic heterocyclic group include [4-{4-amino-2-(trifluoromethyl)phenoxy}phenyl]hexafluoropropane, 2-trifluoromethyl-p-phenylenediamine, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 4,4'-(9-fluorenylidene)dianiline, 2,7-diaminofluorene, 1,5-diaminonaphthalene, and 3,7-diamino-2,8-dimethyldibenzothiophene 5,5-dioxide.

[0084] Examples of aliphatic or alicyclic diamines include: Diamines having saturated aliphatic hydrocarbon groups, such as 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,14-diaminotetradecane, and 1,16-diaminohexadecane; Diamines having unsaturated aliphatic hydrocarbon groups, such as 1,9-diaminononene, 1,10-diaminodecene, 1,11-diaminoundecene, 1,12-diaminododecene, 1,14-diaminotetradecene, and 1,16-diaminohexadecene; 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, isophoronediamine, bis(aminomethyl)norbornane, 1,3-diaminoadamantane, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, 3,3',5,5'-tetraethyl-4,4'-diaminodicyclohexylmethane, 3,5-diethyl-3',5'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexyl ether, 3,3'-dimethyl-4,4'-diaminodicyclohexyl Ether, 3,3'-diethyl-4,4'-diaminodicyclohexyl ether, 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexyl ether, 3,3',5,5'-tetraethyl-4,4'-diaminodicyclohexyl ether, 3,5-diethyl-3',5'-dimethyl-4,4'-diaminodicyclohexyl ether, 2,2-bis(4-aminocyclohexyl)propane saturated propane such as 2,2-bis(3-methyl-4-aminocyclohexyl)propane, 2,2-bis(3-ethyl-4-aminocyclohexyl)propane, 2,2-bis(3,5-dimethyl-4-aminocyclohexyl)propane, 2,2-bis(3,5-diethyl-4-aminocyclohexyl)propane, and 2,2-(3,5-diethyl-3',5'-dimethyl-4,4'-diaminodicyclohexyl)propane. alicyclic Diamines containing hydrocarbon groups; Diamines having unsaturated alicyclic hydrocarbon groups, such as bis(aminomethyl)norbornene and 4,4'-diaminodicyclohexenylmethane; Diamines derived from dimers (also called dimer acids) of unsaturated fatty acids such as monounsaturated fatty acids like crotonic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, and nervonic acid; diunsaturated fatty acids such as linoleic acid, eicosadienoic acid, and docosadienoic acid; and triunsaturated fatty acids such as linolenic acid, pinolenic acid, eleostearic acid, meadic acid, dihomo-γ-linolenic acid, and eicosatrienoic acid; and dimer amines such as hydrogenated diamines in which the carbon-carbon double bond contained within the molecule is hydrogenated. These are some examples.

[0085] From the viewpoint of reducing dielectric constant, the diamine preferably includes an alicyclic diamine. In particular, it is more preferable that the diamine includes at least one selected from dimeramines (unhydrogenated dimeramines and hydrogenated dimeramines). When the polyamic acid contains a structure derived from a dimeramine, the dielectric constant and dielectric loss tangent of the polyimide can be reduced. From the viewpoint of maintaining mechanical strength, the diamine preferably includes an aromatic diamine.

[0086] In polyamic acid, the content of structures derived from aliphatic or alicyclic diamines is preferably 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid. More preferably, it is 30% by mass or more, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass. The content of structures derived from aliphatic or alicyclic diamines is 100% by mass or less, based on the total mass of all diamine-derived structures contained in the polyamic acid, for example, 90% by mass or less, or 70% by mass or less.

[0087] <Tetracarboxylic acid dianhydride> The tetracarboxylic dianhydride that can be used in the method for producing the polyamic acid-containing liquid of the above embodiment, and the tetracarboxylic dianhydride in the "structural unit derived from tetracarboxylic dianhydride" contained in the polyamic acid-containing liquid of the above embodiment, may include aromatic tetracarboxylic dianhydride, aliphatic or alicyclic tetracarboxylic dianhydride, or both.

[0088] In this disclosure, an aromatic tetracarboxylic dianhydride may be a compound having at least one aromatic ring and two acid anhydride groups bonded to at least one aromatic ring. If the aromatic tetracarboxylic dianhydride has two or more aromatic rings, the two or more aromatic rings may be identical or different. If the aromatic tetracarboxylic dianhydride has two or more aromatic rings, the two acid anhydride groups may be bonded to one aromatic ring, or the two acid anhydride groups may be bonded to different aromatic rings. The aromatic tetracarboxylic dianhydride may further have at least one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups.

[0089] In this disclosure, an aliphatic or alicyclic tetracarboxylic dianhydride has at least one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups, and two acid anhydride groups, and does not fall under the category of an aromatic tetracarboxylic dianhydride. Tetracarboxylic acid dianhydride This may be the case. The aliphatic or alicyclic tetracarboxylic dianhydride may further have at least one aromatic ring.

[0090] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, and 2,2-bis(2,3-dicarboxyphenyl phenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 4,4-(p-phenylenedioxy)diphthalic acid dianhydride, 4,4-(m-phenylenedioxy)di Phthalic acid dianhydride, 2,2',6,6'-biphenyltetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic acid dianhydride, 4,4'-(hexafluorotrimethylene)-diphthalic acid dianhydride, Examples of tetracarboxylic dianhydrides having aromatic hydrocarbon groups include 4,4'-(octafluorotetramethylene)-diphthalic acid dianhydride, 1,2,5,6-naphthalenedicarboxylic acid dianhydride, 1,4,5,8-naphthalenedicarboxylic acid dianhydride, 2,3,6,7-naphthalenedicarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride.

[0091] Examples of aliphatic or alicyclic tetracarboxylic dianhydrides include: Tetracarboxylic acid dianhydrides having saturated aliphatic hydrocarbon groups, such as ethylenetetracarboxylic acid dianhydride and butanetetracarboxylic acid dianhydride; Tetracarboxylic acid dianhydrides having saturated alicyclic hydrocarbon groups, such as 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, and 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride; 1,1-Bis(2,3-Dicarboxycyclohexyl)ethane dianhydride, Bis(2,3-Dicarboxycyclohexyl)methane dianhydride, Bis(3,4-Dicarboxycyclohexyl)methane dianhydride, 3,3',4,4'-Bicyclohexyltetracarboxylic acid dianhydride, 2,2-Bis(3,4-Dicarboxycyclohexyl)propane dianhydride, 2,2-Bis(2,3-Dicarboxycyclohexyl)propane dianhydride, Bis(3,4-Dicarboxycyclohexyl)sulfone dianhydride, Bis(3,4-Dicarboxycyclohexyl)ether dianhydride, Bis(2,3-Dicarboxycyclohexyl)ether dianhydride, 2,2',6,6'-Bicyclohexyl Tetracarboxylic acid dianhydrides having alicyclic hydrocarbon groups, such as lohexyltetracarboxylic acid dianhydride, 1,2,5,6-decahydronaphthalenedicarboxylic acid dianhydride, 1,4,5,8-decahydronaphthalenedicarboxylic acid dianhydride, 2,3,6,7-decahydronaphthalenedicarboxylic acid dianhydride, octahydrobiphenylene-4a,8b:4b,8a-tetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic acid dianhydride, and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride. These are some examples.

[0092] In polyamic acids, the tetracarboxylic dianhydride preferably includes an aromatic tetracarboxylic dianhydride. In particular, the tetracarboxylic dianhydride preferably includes at least one selected from pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0093] Preferably, the content of structures derived from pyromellitic dianhydride is 50% by mass or more, based on the total mass of structures derived from all tetracarboxylic dianhydrides contained in the polyamic acid. More preferably, it is 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass. The content of structures derived from pyromellitic dianhydride is 100% by mass or less, based on the total mass of structures derived from all tetracarboxylic dianhydrides contained in the polyamic acid, for example, 90% by mass or less, or 70% by mass or less.

[0094] <Other monomers> The method for producing the polyamic acid-containing solution in the above-described embodiment can use any monomer, such as amines other than diamines and acid anhydrides other than tetracarboxylic dianhydrides. The polyamic acid contained in the polyamic acid-containing solution in the above-described embodiment may include any structure, such as a structure derived from an amine other than a diamine or a structure derived from an acid anhydride other than tetracarboxylic dianhydride. Examples of amines include diamines, monoamines, and trifunctional or higher amines. Examples of acid anhydrides include tetracarboxylic dianhydrides, dicarboxylic anhydrides, and tricarboxylic anhydrides.

[0095] In polyamic acid, the content of structures derived from diamines is, for example, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total mass of all amine-derived structures contained in the polyamic acid. In polyamic acid, the content of structures derived from tetracarboxylic dianhydrides is, for example, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total mass of all acid anhydride-derived structures contained in the polyamic acid.

[0096] <Solvent> Examples of solvents that can be used in the method for producing the polyamic acid-containing liquid of the above-described embodiment, and solvents that the polyamic acid-containing liquid of the above-described embodiment may contain, include polar organic solvents such as N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), 3-methoxy-N,N-dimethylpropanamide (MPA), N,N'-dimethylformamide, N,N'-dimethylpropylene urea [1,3-dimethyl-3,4,5,6-tetrahydropyridimine-2(1H)-one], dimethyl sulfoxide, dimethylacetamide (DMAc), diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. The solvent preferably contains at least one selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), 3-methoxy-N,N-dimethylpropanamide (MPA), and dimethylacetamide (DMAc), and more preferably contains at least one selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), 3-methoxy-N,N-dimethylpropanamide (MPA), and dimethylacetamide (DMAc).

[0097] <Polyamic acid-containing liquid for insulating materials, heat-resistant insulating materials, or printed circuit boards> Polyamic acid-containing liquids can be preferably used as insulating compositions, heat-resistant insulating compositions, or printed circuit board compositions. Depending on the application, these compositions may further contain any components such as polyamides, polyethersulfones, acrylic polymers, epoxy compounds, isocyanate compounds, melamine compounds, fillers, defoamers, preservatives, and surfactants. The compositions can be manufactured, for example, by mixing and stirring the polyamic acid-containing liquid with any components used as needed. The polyamic acid content can be within a range suitable for the application of the composition. The polyamic acid content is, for example, 5-30% by mass, 8-25% by mass, or 10-23% by mass, based on the mass of the composition.

[0098] <Polyimide> Polyimides can be obtained by dehydrating and cyclizing (sometimes called "imidization") polyamic acids. A method for producing polyimides includes obtaining polyimides using a polyamic acid-containing solution. The method of imidization is not particularly limited. A method of heating the polyamic acid-containing solution is preferred because it is simple. The heating temperature is, for example, 250 to 400°C.

[0099] <Molded body, insulator, or heat-resistant insulator> Polyamic acid can be used in the manufacture of molded articles, insulators, and heat-resistant insulators. Methods for manufacturing molded articles, insulators, and heat-resistant insulators include obtaining them using a polyamic acid-containing liquid. There are no particular restrictions on the shape of the molded articles, insulators, and heat-resistant insulators; any shape suitable for the application is acceptable. For example, they may be in the form of films, plates, membranes, or layers. Molded articles, insulators, and heat-resistant insulators can be used in various electronic and mechanical components.

[0100] <Printed circuit board> Polyamic acid can be used in the manufacture of printed circuit boards (PCBs). A method for manufacturing a PCB includes obtaining a PCB using a polyamic acid-containing solution. Examples of PCBs include printed wiring boards and printed circuit boards. Examples of PCBs include flexible boards and rigid boards. Examples of PCBs include single-sided boards, double-sided boards, and multilayer boards. For example, materials, protective films, insulating layers, etc., for these boards can be obtained using a polyamic acid-containing solution.

[0101] An example of a flexible substrate is a substrate comprising a base film, the base film of which is obtained using a polyamic acid-containing liquid. Another example of a flexible substrate is a substrate comprising a base film and a heat-resistant insulating layer formed on the base film, the heat-resistant insulating layer of which is obtained using a polyamic acid-containing liquid.

[0102] <Example of an embodiment> Preferred examples of embodiments of the present invention are listed below. Embodiments of the present invention are not limited to the following examples.

[0103] [1] A prepolymer-containing solution containing an amidic acid prepolymer, a diamine, and a tetracarboxylic acid dianhydride A method for producing a polyamic acid-containing liquid, comprising obtaining a polyamic acid-containing liquid using and . In this disclosure, the amidoic acid prepolymer has a structure derived from a diamine and a tetracarboxylic acid dianhydride It is a polyamic acid containing the derived structure. [2] A method for producing the polyamic acid-containing liquid described in [1] above, comprising either step (1) or step (2) below. (1) To obtain a polyamic acid-containing solution containing a polyamic acid using a prepolymer-containing solution that includes an aromatic diamine-derived structure and a tetracarboxylic dianhydride-derived structure, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride. (2) A prepolymer-containing solution containing an amidic acid prepolymer that includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a polyamidic acid-containing solution containing a polyamidic acid using a diamine and a tetracarboxylic dianhydride. A preferred embodiment of step (1) above includes the following [3] to

[10] . A preferred embodiment of step (2) above includes the following

[11] to

[17] . The resulting polyamic acid is preferably one of the following

[18] to

[31] .

[0104] [3] A method for producing a polyamic acid-containing solution, comprising obtaining a polyamic acid-containing solution using a prepolymer-containing solution containing an amidic acid prepolymer including an aromatic diamine-derived structure and a tetracarboxylic dianhydride-derived structure, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride. [4] Obtaining the prepolymer-containing liquid using an aromatic diamine, a tetracarboxylic dianhydride, and a solvent, A method for producing the polyamic acid-containing liquid according to [3] above, comprising adding the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid to obtain the polyamic acid-containing liquid. [5] A method for producing a polyamic acid-containing liquid according to [3] or [4], comprising adding one or both of the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more separate additions. [6] A method for producing a polyamic acid-containing liquid according to any one of [3] to [5] above, wherein the content of the amide acid prepolymer in the prepolymer-containing liquid is 30.0% by mass or less. [7] A method for producing a polyamic acid-containing liquid according to any one of [3] to [6] above, wherein the mass of the amide acid prepolymer relative to the mass of the polyamic acid is 10.0% by mass or more. [8] A method for producing a polyamic acid-containing liquid according to any one of [3] to [7] above, wherein the content of the amide acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or more, and the mass of the amide acid prepolymer relative to the mass of the polyamic acid is 50.0% by mass or more. [9] A method for producing a polyamic acid-containing liquid according to any one of [3] to [8] above, wherein the amidic acid prepolymer further comprises a structure derived from an aliphatic or alicyclic diamine.

[10] A method for producing a polyamic acid-containing liquid that satisfies any embodiment of [3] to [9] above and any embodiment of

[18] to

[31] below.

[0105]

[11] A method for producing a polyamic acid-containing solution, comprising obtaining a polyamic acid-containing solution using a prepolymer-containing solution containing an amidic acid prepolymer having a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a diamine and a tetracarboxylic dianhydride.

[12] Obtaining the prepolymer-containing liquid using an aliphatic or alicyclic diamine, a tetracarboxylic dianhydride, and a solvent, A method for producing the polyamic acid-containing liquid according to

[11] above, comprising adding the diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid to obtain the polyamic acid-containing liquid.

[13] A method for producing a polyamic acid-containing liquid according to

[11] or

[12] , comprising adding one or both of the diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more separate additions.

[14] A method for producing a polyamic acid-containing liquid according to any one of

[11] to

[13] above, wherein the content of the amide acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or less.

[15] A method for producing a polyamic acid-containing liquid according to any one of

[11] to

[14] above, wherein the mass of the amide acid prepolymer relative to the mass of the polyamic acid is 10.0% by mass or more.

[16] A method for producing a polyamic acid-containing liquid according to any one of

[11] to

[15] above, wherein the amidic acid prepolymer further comprises a structure derived from an aromatic diamine.

[17] A method for producing a polyamic acid-containing liquid that satisfies any of the embodiments described in

[11] to

[16] above and any of the embodiments described in

[18] to

[31] below.

[0106]

[18] A polyamic acid containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent, A polyamic acid-containing solution that satisfies either or both of the following conditions (1) and (2). (1) The content of components derived from amines and carboxylic acid anhydrides is 20.0% by mass or more, and the turbidity is 2.5 NTU or less. (2) The content of the polyamic acid is 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent.

[19] A polyamic acid-containing solution according to

[18] above, satisfying the above (1).

[20] A polyamic acid-containing solution according to

[18] or

[19] above, satisfying the above (2).

[21] A polyamic acid containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent, A polyamic acid-containing solution that satisfies either or both of the following conditions (3) and (4). (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from the amine and carboxylic acid anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more. (4) The ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing solution to the mass of the polyamic acid-containing solution is 18.0% by mass or more.

[22] A polyamic acid-containing solution as described in

[21] above, satisfying (3) above. The polyamic acid-containing solution may further satisfy any of

[18] to

[20] above.

[23] A polyamic acid-containing solution according to

[21] or

[22] above, which satisfies (4) above. The polyamic acid-containing solution may further satisfy any of

[18] to

[20] above.

[24] A polyamic acid-containing solution according to any one of

[18] to

[23] above, wherein the structure derived from the tetracarboxylic dianhydride includes a structure derived from pyromellitic dianhydride.

[25] The polyamic acid-containing solution according to any one of

[18] to

[24] above, wherein the polyamic acid further comprises a structure derived from an aromatic diamine.

[26] The polyamic acid-containing solution according to any one of

[18] to

[25] above, wherein the content of the aliphatic or alicyclic diamine-derived structure is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid.

[27] The polyamic acid-containing solution according to

[24] , wherein the content of the structure derived from pyromellitic dianhydride is 50% by mass or more, based on the total mass of all tetracarboxylic dianhydride-derived structures contained in the polyamic acid.

[28] The content of the aliphatic or alicyclic diamine-derived structure is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid. A polyamic acid-containing solution according to any one of the above

[24] to

[27] , wherein the content of the structure derived from pyromellitic dianhydride is 50% by mass or more, based on the total mass of all tetracarboxylic dianhydride-derived structures contained in the polyamic acid.

[29] The polyamic acid-containing solution according to any one of

[18] to

[28] above, wherein the aliphatic or alicyclic diamine-derived structure includes a structure derived from an alicyclic diamine.

[30] The polyamic acid-containing solution according to any one of

[18] to

[29] above, wherein the aliphatic or alicyclic diamine-derived structure includes a dimer amine-derived structure.

[31] A polyamic acid-containing liquid according to any of

[18] to

[30] above, for use as an insulating material, a heat-resistant insulating material, or a printed circuit board.

[0107]

[32] A method for producing polyimide, comprising obtaining polyimide using a polyamic acid-containing solution described in any of

[18] to

[31] above.

[33] A method for producing a molded article, comprising obtaining a molded article using a polyamic acid-containing liquid as described in any of

[18] to

[31] above.

[34] A method for manufacturing a printed circuit board, comprising obtaining a printed circuit board using a polyamic acid-containing solution described in any of

[18] to

[31] above. [Examples]

[0108] Embodiments of the present invention will be specifically described by reference to examples. Embodiments of the present invention are not limited to the following examples.

[0109] The abbreviations used in the examples represent the following: PMDA: Pyromellitic dianhydride ODA: Oxydianiline PACM: Paradiaminodicyclohexylmethane NBDA: Norbornanediamine DDA: Dimer amine (molecular weight 534.99, "PRIAMINE1075", Croda Japan Co., Ltd.) DMAc: Dimethylacetamide

[0110] <Preparation and evaluation of polyamic acid-containing solutions (1)> Polyamic acid-containing solutions were prepared and evaluated using either manufacturing method Rs or manufacturing method Ls.

[0111] [Example 1] In a fume hood, a solution containing the amide acid prepolymer (0.586 g) and dehydrated DMAc (4.696 g) shown in Table 1 was prepared in a 50 mL screw-cap tube. Next, ODA (0.295 g, 1.47 mmol), PACM (0.575 g, 2.73 mmol), and dehydrated DMAc (4.683 g) were placed in a sample bottle and stirred to prepare a diamine solution. The diamine solution and the entire amount of PMDA (0.910 g, 0.417 mmol) were added to the amide acid prepolymer solution, and the mixture was stirred at room temperature for a total of 24 hours to obtain polyamic acid solution 1.

[0112] [Example 2] In a fume hood, a solution containing the amide acid prepolymer (0.588 g) and dehydrated DMAc (4.694 g) shown in Table 1 was prepared in a 50 mL screw-cap tube. Next, PACM (0.863 g, 4.10 mmol) and dehydrated DMAc (4.683 g) were placed in a sample bottle and stirred to prepare a diamine solution. The diamine solution and the entire amount of PMDA (0.900 g, 0.410 mmol) were added to the amide acid prepolymer solution, and the mixture was stirred at room temperature for 8 hours to obtain polyamic acid solution 2.

[0113] [Example 3] In a fume hood, a solution containing the amide acid prepolymer (0.588 g) and dehydrated DMAc (4.694 g) shown in Table 1 was prepared in a 50 mL screw-cap tube. Next, PACM (0.863 g, 4.10 mmol) and dehydrated DMAc (4.683 g) were placed in a sample bottle and stirred to prepare a diamine solution. Subsequently, the diamine solution and PMDA (0.900 g, 4.10 mmol) were divided into four equal parts and added to the amide acid prepolymer solution in four separate additions at 10-minute intervals while stirring the amide acid prepolymer. The mixture was stirred at room temperature for a total of 8 hours to obtain polyamic acid solution 3. The stirring time is the time from the first addition to the end of stirring.

[0114] [Example 4] In a fume hood, a solution containing the amide acid prepolymer (0.586 g) and dehydrated DMAc (7.027 g) shown in Table 1 was prepared in a 50 mL screw-cap tube. Next, ODA (0.575 g, 2.87 mmol), PACM (0.288 g, 1.37 mmol), and dehydrated DMAc (2.342 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the entire amount of the diamine solution and PMDA (0.923 g, 4.23 mmol) were added to the amide acid prepolymer solution, and the mixture was stirred at room temperature for 3 hours to obtain polyamic acid solution 4.

[0115] [Example 5] In a fume hood, a solution containing the amide acid prepolymer (0.360 g) and dehydrated DMAc (6.123 g) shown in Table 1 was prepared in a 50 mL screw-cap tube. Next, ODA (0.575 g, 2.87 mmol), PACM (0.400 g, 1.90 mmol), and dehydrated DMAc (3.278 g) were placed in a sample bottle and stirred to prepare a diamine solution. The diamine solution and the entire amount of PMDA (1.04 g, 4.77 mmol) were added to the amide acid prepolymer solution, and the mixture was stirred at room temperature for 24 hours to obtain polyamic acid solution 5.

[0116] [Methods for measuring polyamic acid content, turbidity, etc.] The polyamic acid content and turbidity of the polyamic acid-containing solution were measured using the following method. The measurement results are shown in Table 1. In Examples 1-5, the polyamic acid-containing solutions contained precipitates formed during the polymerization reaction, so solid residue could not be recovered by filtration.

[0117] (Polyamic acid content (indicated as (2) in the table)) The polyamic acid content was measured using the following procedure. A polyamic acid-containing solution (25°C) was pressure-filtered using a stainless steel mesh (150 mesh, "Stainless Mesh #150" (Material: SUS316, Mesh count: 150, Wire diameter: 0.06 mm, Mesh opening: 0.109 mm, Open area: 41.6%, Weave: Plain weave), tantore Co., Ltd.) to remove solid residue and obtain a polyamic acid solution as filtrate. 1.5 g (initial mass) was weighed from the polyamic acid solution using a high-precision electronic balance and added to an aluminum petri dish. The polyamic acid solution added to the aluminum petri dish was heated at 200°C for 2 hours to evaporate the solvent and dehydrate and cyclize the polyamic acid to obtain polyimide. The value obtained by weighing the polyimide with a high-precision electronic balance was taken as the post-heating mass. The NV2 value (mass%) (Nonvolatile content) was obtained by dividing the post-heating mass by 1.5 g (initial mass) and multiplying by 100. The polyamic acid content was determined by correcting for the amount of water lost due to the dehydration and cyclization reaction of polyamic acid using the following formula. The average molecular weight of diamines was calculated using the molecular weight and mole fraction of each diamine in the structure derived from the "diamine" contained in polyamic acid. The average molecular weight of tetracarboxylic dianhydrides was calculated using the molecular weight and mole fraction of each tetracarboxylic dianhydride in the structure derived from the "tetracarboxylic dianhydride" contained in polyamic acid. Polyamic acid content (mass %) = NV2 value × {(average molecular weight of diamine) + (average molecular weight of tetracarboxylic dianhydride)} / {(average molecular weight of diamine) + (average molecular weight of tetracarboxylic dianhydride) - molecular weight of water 18.01 × 2}

[0118] (Content of components derived from amines and carboxylic acid anhydrides (indicated as (1) in the table)) The NV1 value (mass%) was determined using the same procedure as above (for polyamic acid content), except that the unfiltered polyamic acid-containing solution was heated. Using the NV1 value (mass%) instead of the NV2 value (mass%) in the above calculation formula, the content of components derived from amines and carboxylic acid anhydrides relative to the mass of the polyamic acid-containing solution was determined using the average molecular weight of diamines and the average molecular weight of tetracarboxylic dianhydrides in the components derived from amines and carboxylic acid anhydrides contained in the polyamic acid-containing solution.

[0119] (Ratio of polyimide mass (indicated as (4) in the table)) The NV2 value (mass%) obtained above was defined as the ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing solution to the mass of the polyamic acid-containing solution.

[0120] (Content of components derived from amines and carboxylic acid anhydrides after heating (Table (3))) The NV1 value (mass%) obtained above was defined as the ratio of the mass of components derived from amines and carboxylic acid anhydrides obtained by heating the polyamic acid-containing solution to the mass of the polyamic acid-containing solution.

[0121] (Turbidity) Turbidity was measured using the transmitted-scatter light method and determined based on a calibration curve using formazin standard solution. The measurement conditions are as follows. Measurement device: Spectrocolorimeter "COH400" (Nippon Denshoku Industries Co., Ltd.) Light source: Tungsten lamp, color temperature 2500 degrees (absolute temperature) Cell dimensions (optical path length): 10mm Angle of reception relative to incident light: 90±30° Peak sensitivity characteristic: 500nm Sample temperature: 25℃

[0122] (viscosity) Viscosity (ηinh) measurements were performed using an Ostwald viscometer in a KINEMATIC VISCOSITY BATH TV-5S (THOMAS KAGAKU CO.,Ltd.). Samples were prepared by dissolving polyamic acid in DMAc to a concentration of 0.5 g / dL, and the flow time was measured at 30°C.

[0123] (mass average molecular weight) The mass-average molecular weight was measured by gel permeation chromatography (GPC) and converted using a calibration curve for standard polystyrene. The calibration curve was approximated by a cubic equation using a set of five standard polystyrene samples ("TSK standard POLYSTYRENE," Tosoh Corporation). The GPC conditions are shown below. GPC equipment: High-speed GPC system "HLC-8320GPC" (Tosoh Corporation) Detector: UV-8320 ultraviolet absorption detector (Tosoh Corporation) Column: "Gelpack GL-S300MDT-5" (2 pieces total) (Showa Denko Materials Co., Ltd.) Eluent: THF / DMF=1 / 1 (volume ratio) + LiBr (0.06mol / L) + H3PO4 (0.06mol / L) Flow rate: 1mL / min Column size: 8mm I.D. × 300mm Sample concentration: 5 mg / 1 mL Injection volume: 5μL Measurement temperature: 40℃

[0124] <Evaluation of polyamic acid-containing solution> (Film production) A film was prepared using a polyamic acid-containing solution (varnish) according to the following procedure. The surface of a commercially available glass substrate was degreased with acetone, and polyamic acid varnish was applied using a film applicator with a film thickness adjustment function to achieve a film thickness of 25 μm after imidization. The applied varnish was pre-dried using a hot plate at 80°C for 60 minutes to form a polyamic acid layer. Next, the polyamic acid layer was heated in an inert gas oven under a nitrogen atmosphere at 350°C for 1 hour to obtain polyimide film 1. After immersing the glass substrate on which the film was formed in warm water for about 15 minutes, film 1 was peeled off the glass substrate. Furthermore, polyimide film 2 was obtained using the same procedure as above, except that a polyamic acid-containing solution (varnish) was applied so that the film thickness after imidization was 50 μm, and film 2 was peeled off from the glass substrate.

[0125] (Relative permittivity and dielectric loss tangent) Film 1 was cut to a size of 60 mm x 60 mm, dried at 125°C for 1 hour, and then quickly measured. The dielectric properties of the film (dielectric constant Dk and dielectric loss tangent Df) were measured using the cavity resonator method (TE mode). A compact USB vector network analyzer ("MS46122B", Anritsu Corporation) was used for the measurements. The conditions were a frequency of 10 GHz and a measurement temperature of 25°C.

[0126] (Film forming property) After cutting Film 1 and Film 2 to 140 mm x 70 mm, the film thickness was measured at 15 points (5 vertical and 3 horizontal points at 20-30 mm intervals) using a high-precision digital micrometer ("MDH-25MB", Mitutoyo Corporation), and evaluated according to the following criteria. ◎: When the coating is applied so that the film thickness after imidization is 50 μm, the variation in the in-plane distribution of film thickness is within 50 μm ± 3 μm (i.e., the film thickness at all 15 points is between 47 and 53 μm). ○: When the film thickness after imidization is applied to 25 μm, the variation in the in-plane distribution of film thickness is within 25 μm ± 3 μm (i.e., the film thickness at all 15 points is between 22 and 28 μm). ×: When the coating is applied so that the film thickness after imidization is 25 μm, the variation in the in-plane distribution of film thickness is greater than 25 μm ± 3 μm (i.e., the film thickness at one or more points is less than 22 μm or greater than 28 μm).

[0127] [Table 1]

[0128] <Preparation and evaluation of polyamic acid-containing solution (2)> Polyamic acid-containing solutions were prepared and evaluated using either the Ri or Li manufacturing method.

[0129] [Example 6] In a fume hood, ODA (0.575 g, 2.87 mmol), PMDA (0.586 g, 2.67 mmol), and anhydrous DMAc (7.025 g) were placed in a 50 mL screw-cap tube and stirred for 1 hour. Separately, PACM (0.575 g, 2.73 mmol) and anhydrous DMAc (2.342 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the entire contents of the diamine solution and PMDA (0.637 g, 2.92 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 24 hours to obtain polyamic acid-containing solution 6.

[0130] [Example 7] In a fume hood, ODA (0.626 g, 3.13 mmol), PMDA (0.634 g, 2.91 mmol), and anhydrous DMAc (9.366 g) were charged into a 50 mL screw-cap tube and stirred for 1 hour. Separately, NBDA (0.626 g, 4.06 mmol) and anhydrous DMAc (1.873 g) were charged into a sample bottle and stirred to prepare a diamine solution. Then, the entire contents of the diamine solution and PMDA (0.933 g, 4.28 mmol) were charged into a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 7.

[0131] [Example 8] In a fume hood, ODA (0.870 g, 4.34 mmol), PMDA (0.220 g, 1.01 mmol), and dehydrated DMAc (7.025 g) were placed in a 50 mL screw-cap tube and stirred for 1 hour. Separately, DDA (0.378 g, 0.71 mmol) and dehydrated DMAc (2.342 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the entire contents of the diamine solution and PMDA (0.881 g, 4.04 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 8.

[0132] [Example 9] In a fume hood, ODA (0.703 g, 3.51 mmol), PMDA (0.204 g, 0.94 mmol), and dehydrated DMAc (7.025 g) were placed in a 50 mL screw-cap tube and stirred for 1 hour. Separately, DDA (0.626 g, 1.17 mmol) and dehydrated DMAc (2.342 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the entire contents of the diamine solution and PMDA (0.817 g, 3.74 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 3 hours to obtain polyamic acid-containing solution 9.

[0133] [Example 10] In a fume hood, ODA (0.402 g, 2.01 mmol), PMDA (0.175 g, 0.80 mmol), and dehydrated DMAc (7.025 g) were placed in a 50 mL screw-cap tube and stirred for 1 hour. Separately, DDA (1.073 g, 2.01 mmol) and dehydrated DMAc (2.342 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the diamine solution and the entire amount of PMDA (0.700 g, 3.21 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 3 hours to obtain polyamic acid-containing solution 10.

[0134] [Example 11] In a fume hood, ODA (0.288g, 1.44 mmol), PACM (0.288g, 1.37 mmol), PMDA (0.613g, 2.81 mmol), and dehydrated DMAc (8.429g) were charged into a 50 mL screw-cap tube and stirred for 1 hour. Separately, PACM (0.288g, 1.37 mmol) and dehydrated DMAc (0.937 g) were charged into a sample bottle and stirred to prepare a diamine solution. Then, the entire amounts of the diamine solution, ODA (0.288g, 1.44 mmol), and PMDA (0.610g, 2.80 mmol) were charged into a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 11.

[0135] [Example 12] PACM (0.575 g, 2.73 mmol), PMDA (0.596 g, 2.73 mmol), and anhydrous DMAc (9.366 g) were placed in a 50 mL screw-cap tube in a fume hood and stirred for 1 hour. Then, the entire amounts of ODA (0.575 g, 2.87 mmol) and PMDA (0.627 g, 2.87 mmol) were placed in the screw-cap tube and stirred at room temperature for a total of 3 hours to obtain polyamic acid-containing solution 12.

[0136] [Example 13] PACM (0.575 g, 2.73 mmol), PMDA (0.596 g, 2.73 mmol), and dehydrated DMAc (8.429 g) were placed in a 50 mL screw-cap tube in a fume hood and stirred for 1 hour. Separately, PACM (0.288 g, 1.37 mmol) and dehydrated DMAc (0.937 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the entire amounts of the diamine solution, ODA (0.288 g, 1.44 mmol), and PMDA (0.627 g, 2.87 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 13.

[0137] [Example 14] PACM (0.577 g, 2.74 mmol), PMDA (0.598 g, 2.74 mmol), and anhydrous DMAc (8.429 g) were placed in a 50 mL screw-cap tube in a fume hood and stirred for 1 hour. Separately, PACM (0.577 g, 2.74 mmol) and DMAc (0.937 g) were placed in a sample bottle and stirred to prepare a diamine solution. Then, the diamine solution and the entire amount of PMDA (0.637 g, 2.92 mmol) were placed in a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 14.

[0138] [Example 15] In a fume hood, PACM (0.288 g, 1.37 mmol) and dehydrated DMAc (4.683 g) were placed in a 50 mL screw-cap tube and stirred to prepare diamine solution 1. Next, PMDA (0.300 g, 1.37 mmol) was added to diamine solution 1 and stirred for 10 minutes. Separately, PACM (0.863 g, 4.10 mmol) and dehydrated DMAc (4.683 g) were placed in a sample bottle and stirred to prepare diamine solution 2. Then, PMDA (0.900 g, 4.10 mmol) and diamine solution 2 were each divided into three equal parts and added to screw-cap tubes at 10-minute intervals in three separate additions while stirring the contents of the screw-cap tubes. The mixture was stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 15. The stirring time is the time from the first addition to the end of stirring.

[0139] [Example 16] In a fume hood, NBDA (0.575 g, 3.73 mmol), PMDA (0.586 g, 2.69 mmol), and anhydrous DMAc (8.429 g) were placed in 50 mL screw-cap tubes and stirred for 1 hour. Separately, PACM (0.575 g, 2.73 mmol) and anhydrous DMAc (0.937 g) were placed in sample bottles to prepare diamine solutions. Then, the diamine solutions and PMDA (0.637 g, 2.92 mmol) were added to the screw-cap tubes in two and three separate additions, respectively, every 10 minutes, and stirred at room temperature for a total of 8 hours to obtain polyamic acid solution 16. The diamine solution was divided into two equal parts, and the PMDA was divided into three parts in a ratio of 5:4:1.

[0140] [Comparative Example 1] A diamine solution was prepared by charging PACM (1.151 g, 5.47 mmol) and anhydrous DMAc (9.366 g) into a 50 mL screw-cap tube in a fume hood. Then, PMDA (1.195 g, 5.48 mmol) was added in four portions at 10-minute intervals. After the addition, the mixture was stirred at room temperature for a total of 24 hours to obtain a polyamic acid-containing solution.

[0141] [Comparative Example 2] In a fume hood, PACM (0.342 g, 1.62 mmol) and anhydrous DMAc (9.366 g) were charged into a 50 mL screw-cap tube to prepare a diamine solution. Then, the total amounts of ODA (0.797 g, 3.98 mmol) and PMDA (1.221 g, 5.60 mmol) were added. After addition, the mixture was stirred at room temperature for a total of 24 hours to obtain a polyamic acid-containing solution.

[0142] [Methods for measuring polyamic acid content, turbidity, etc.] The polyamic acid-containing solutions were measured in the same manner as in (1) for preparation and evaluation. The measurement results are shown in Tables 2-1 to 2-3. In the polyamic acid-containing solutions of Examples 6 to 16, the precipitates formed during the polymerization reaction were dissolved, so the solid residue could not be recovered by filtration.

[0143] <Evaluation of polyamic acid-containing solution> The polyamic acid-containing solution was prepared and evaluated in the same manner as in (1). The evaluation results are shown in Table 2. In Comparative Examples 1 and 2, it was not possible to produce a film using the polyamic acid-containing solution.

[0144] [Table 2-1]

[0145] [Table 2-2]

[0146] [Table 2-3]

[0147] <Preparation and evaluation of polyamic acid-containing solutions (3)> [Example 17] (Preparation of polyamic acid-containing solution 17a) Polyamic acid-containing solution 17a was prepared using manufacturing method Ri. In a fume hood, ODA (24.5 g, 0.122 mol), PMDA (7.11 g, 0.033 mol), and dehydrated DMAc (300.0 g) were placed in a 500 mL three-necked flask and stirred for 1 hour. Separately, DDA (21.8 g, 0.041 mol) and dehydrated DMAc (20.0 g) were placed in a sample bottle and stirred to prepare diamine solution a. Then, the entire contents of diamine solution a and PMDA (26.6 g, 0.122 mol) were placed in a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 17a.

[0148] (Preparation of polyamic acid-containing solution 17b) Polyamic acid-containing solution 17a was used as the aromatic prepolymer-containing solution, and polyamic acid-containing solution 17b was prepared according to the manufacturing method Rs. In a 500 mL three-necked flask containing polyamic acid-containing solution 17a, ODA (10.2 g, 0.051 mol) and PMDA (2.97 g, 0.014 mol) were charged and stirred for 1 hour. Separately, DDA (9.10 g, 0.017 mol) and dehydrated DMAc (18.2 g) were charged into a sample bottle and stirred to prepare diamine solution b. Then, the entire contents of diamine solution b and PMDA (11.1 g, 0.051 mol) were charged into a screw-cap tube and stirred at room temperature for a total of 8 hours to obtain polyamic acid-containing solution 17b.

[0149] [Methods for measuring polyamic acid content, turbidity, etc.] The viscosity was measured in the same manner as in (1) for the preparation and evaluation of the polyamic acid-containing solution, except that the viscosity was measured by the following method. The measurement results are shown in Table 3. In Example 17, the polyamic acid-containing solution contained precipitates formed during the polymerization reaction, so the solid residue could not be recovered by filtration.

[0150] (viscosity) Viscosity was measured using a rotary type B viscometer ("TVB-10M", Toki Sangyo Co., Ltd.) with the polyamic acid-containing liquid at a temperature of 30°C and using rotor No. 3.

[0151] <Evaluation of polyamic acid-containing solution> The polyamic acid-containing solution was prepared and evaluated in the same manner as in (1). The evaluation results are shown in Table 3.

[0152] [Table 3]

Claims

1. The process involves obtaining a polyamic acid-containing solution containing a prepolymer containing an amidic acid prepolymer that includes structures derived from aromatic diamines and structures derived from tetracarboxylic dianhydrides, and using an aliphatic or alicyclic diamine and a tetracarboxylic dianhydride to obtain a polyamic acid-containing solution. A method for producing a polyamic acid-containing liquid, wherein the content of the amide acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or more, and the mass of the amide acid prepolymer relative to the mass of the polyamic acid is 50.0% by mass or more.

2. Obtaining the prepolymer-containing liquid using an aromatic diamine, a tetracarboxylic dianhydride, and a solvent, A method for producing a polyamic acid-containing liquid according to claim 1, comprising adding the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid to obtain the polyamic acid-containing liquid.

3. A method for producing a polyamic acid-containing liquid according to claim 1, comprising adding one or both of the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more separate additions.

4. A method for producing a polyamic acid-containing liquid according to claim 1, wherein the content of the amidic acid prepolymer in the prepolymer-containing liquid is 30.0% by mass or less.

5. A method for producing a polyamic acid-containing liquid according to claim 1, wherein the ratio of the mass of the amide acid prepolymer to the mass of the polyamic acid is 90.0% by mass or less.

6. The method for producing a polyamic acid-containing liquid according to claim 1, wherein the amidic acid prepolymer further comprises a structure derived from an aliphatic or alicyclic diamine.

7. A prepolymer-containing solution containing an amidic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride, and a polyamidic acid-containing solution containing a polyamidic acid using an aliphatic or alicyclic diamine and a tetracarboxylic dianhydride, A method for producing a polyamic acid-containing solution, wherein the amidic acid prepolymer further comprises a structure derived from an aliphatic or alicyclic diamine.

8. Obtaining the prepolymer-containing liquid using an aromatic diamine, a tetracarboxylic dianhydride, and a solvent, A method for producing a polyamic acid-containing liquid according to claim 7, comprising adding the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid to obtain the polyamic acid-containing liquid.

9. A method for producing a polyamic acid-containing liquid according to claim 7, comprising adding one or both of the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more separate additions.

10. The method for producing a polyamic acid-containing liquid according to claim 7, wherein the content of the amidic acid prepolymer in the prepolymer-containing liquid is 30.0% by mass or less.

11. The method for producing a polyamic acid-containing liquid according to claim 7, wherein the ratio of the mass of the amide acid prepolymer to the mass of the polyamic acid is 10.0% by mass or more.

12. The polyamic acid comprises a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from a tetracarboxylic dianhydride. A method for producing a polyamic acid-containing liquid according to claim 1, wherein the polyamic acid-containing liquid contains a solvent and satisfies one or both of the following conditions (1) and (2). (1) The content of components derived from amines and carboxylic acid anhydrides is 20.0% by mass or more, and the turbidity is 2.5 NTU or less. (2) The content of the polyamic acid is 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent.

13. A method for producing a polyamic acid-containing liquid according to claim 12, which satisfies (1) above.

14. A method for producing a polyamic acid-containing liquid according to claim 12, which satisfies (2) above.

15. The polyamic acid comprises a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from a tetracarboxylic dianhydride. A method for producing a polyamic acid-containing liquid according to claim 7, wherein the polyamic acid-containing liquid contains a solvent and satisfies one or both of the following conditions (1) and (2). (1) The content of components derived from amines and carboxylic acid anhydrides is 20.0% by mass or more, and the turbidity is 2.5 NTU or less. (2) The content of the polyamic acid is 20.0% by mass or more, based on the total mass of the polyamic acid and the solvent.

16. The polyamic acid comprises a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from a tetracarboxylic dianhydride. A method for producing a polyamic acid-containing liquid according to claim 1, wherein the polyamic acid-containing liquid contains a solvent and satisfies one or both of the following conditions (3) and (4). (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from the amine and carboxylic acid anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more. (4) The ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more.

17. A method for producing a polyamic acid-containing liquid according to claim 16, which satisfies (3) above.

18. A method for producing a polyamic acid-containing liquid according to claim 16, which satisfies (4) above.

19. The polyamic acid comprises a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from a tetracarboxylic dianhydride, A method for producing a polyamic acid-containing liquid according to claim 7, wherein the polyamic acid-containing liquid contains a solvent and satisfies one or both of the following conditions (3) and (4). (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from the amine and carboxylic acid anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more. (4) The ratio of the mass of polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0% by mass or more.

20. A method for producing a polyamic acid-containing solution according to any one of claims 12 to 19, wherein the structure derived from the tetracarboxylic dianhydride includes a structure derived from pyromellitic dianhydride.

21. A method for producing a polyamic acid-containing liquid according to any one of claims 12 to 19, wherein the content of the aromatic diamine-derived structure is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid.

22. A method for producing a polyamic acid-containing liquid according to any one of claims 12 to 19, wherein the content of the aliphatic or alicyclic diamine-derived structure is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid.

23. The method for producing a polyamic acid-containing liquid according to claim 20, wherein the content of the structure derived from pyromellitic dianhydride is 50% by mass or more, based on the total mass of all tetracarboxylic dianhydride-derived structures contained in the polyamic acid.

24. The content of the aliphatic or alicyclic diamine-derived structure is 20% by mass or more, based on the total mass of all diamine-derived structures contained in the polyamic acid. A method for producing a polyamic acid-containing liquid according to claim 20, wherein the content of the structure derived from pyromellitic dianhydride is 50% by mass or more, based on the total mass of all tetracarboxylic dianhydride-derived structures contained in the polyamic acid.

25. A method for producing a polyamic acid-containing solution according to any one of claims 12 to 19, wherein the aliphatic or alicyclic diamine-derived structure includes a structure derived from an alicyclic diamine.

26. A method for producing a polyamic acid-containing solution according to any one of claims 12 to 19, wherein the aliphatic or alicyclic diamine-derived structure includes a dimeramine-derived structure.

27. ​​The method for producing a polyamic acid-containing liquid according to any one of claims 1 to 19, wherein the polyamic acid-containing liquid is for use in printed circuit boards.

28. A method for producing a polyimide, comprising obtaining a polyamic acid-containing liquid by the method for producing a polyamic acid-containing liquid described in any one of Claims 1 to 19, and obtaining a polyimide using the polyamic acid-containing liquid.

29. A method for producing a molded article, comprising obtaining a polyamic acid-containing liquid by the method for producing a polyamic acid-containing liquid described in any one of Claims 1 to 19, and obtaining a molded article using the polyamic acid-containing liquid.

30. A method for producing a printed circuit board, comprising obtaining a polyamic acid-containing liquid by the method for producing a polyamic acid-containing liquid described in any one of Claims 1 to 19, and obtaining a printed circuit board using the polyamic acid-containing liquid.

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