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

Abstract

The present disclosure relates to a method for producing a polyamic acid-containing solution, which comprises obtaining a polyamic acid-containing solution containing a polyamic acid using a prepolymer-containing solution containing an amic acid prepolymer, a diamine, and a tetracarboxylic acid dianhydride.

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, a polyimide, a molded body, and a printed circuit board. Background Art

[0002] Polyimide is widely used in the fields of automobiles, electronic components, displays, etc. due to its high heat resistance, chemical resistance, high mechanical properties, and low dielectric constant. For example, semi-aromatic polyimide 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 can be expected to be used in high-frequency antennas, substrates such as FPC (flexible printed circuit boards), and coil insulation films of inverter drive motors that are advancing in high frequency and high voltage.

[0003] Patent Document 1 discloses a solvent-insoluble polyimide film, wherein more than 15 mol% and less than 50 mol% of a dimer diamine is used relative to the total diamine components. Patent Document 1 also discloses that, for example, by mixing tetracarboxylic dianhydride and diamine in substantially equimolar amounts in a nitrogen-containing polar solvent and performing a polymerization reaction at 10 to 70° C., a polyamic acid solution can be obtained as an optically uniform solution.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-76072 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present disclosure provides a method for easily producing a polyamic acid-containing liquid capable of obtaining a polyimide exhibiting excellent dielectric properties. In addition, the present disclosure provides a polyamic acid-containing liquid capable of obtaining a polyimide exhibiting excellent dielectric properties and exhibiting excellent film-forming properties. Furthermore, the present disclosure provides a method for producing a polyimide exhibiting excellent dielectric properties, a molded article, and a printed circuit board.

[0009] Means for solving problems

[0010] Examples of the embodiments are given below. The present invention is not limited to the following embodiments.

[0011] One embodiment relates to a method for producing a polyamic acid-containing liquid, comprising: obtaining a polyamic acid-containing liquid containing polyamic acid using a prepolymer-containing liquid 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 tetracarboxylic dianhydride.

[0012] Another embodiment relates to a method for producing a polyamic acid-containing liquid, comprising: obtaining a polyamic acid-containing liquid containing polyamic acid using a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from tetracarboxylic dianhydride, a diamine, and tetracarboxylic dianhydride.

[0013] Another embodiment relates to a polyamic acid-containing liquid, comprising a polyamic acid including a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent.

[0014] Satisfies one or both of the following (1) and (2).

[0015] (1) The content of the component derived from amine and carboxylic anhydride is 20.0% by mass or more, and the turbidity is 2.5 NTU or less.

[0016] (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.

[0017] Another embodiment relates to a polyamic acid-containing liquid, comprising a polyamic acid including a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent.

[0018] Satisfy one or both of the following (3) and (4).

[0019] (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from amine and carboxylic anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0020] (4) The ratio of the mass of the polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0021] Some other embodiments relate to the polyamic acid-containing liquid used for an insulating material, a heat-resistant insulating material, or a printed circuit board.

[0022] Some other embodiments relate to methods for producing a polyimide, a molded article, and a printed circuit board, wherein the polyamic acid-containing liquid is used.

[0023] Effects of the Invention

[0024] According to the present disclosure, a method for easily producing a polyamic acid-containing liquid capable of obtaining a polyimide exhibiting excellent dielectric properties can be provided. In addition, according to the present disclosure, a polyamic acid-containing liquid capable of obtaining a polyimide exhibiting excellent dielectric properties and exhibiting excellent film-forming properties can be provided. Furthermore, according to the present disclosure, a method for producing a polyimide exhibiting excellent dielectric properties, a molded article, and a printed circuit board can be provided. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described. The present invention is not limited to the following embodiments. In addition, the following embodiments can be implemented individually or in combination. The combination of multiple embodiments is also included in the present invention.

[0026] In the numerical range recorded in stages in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the upper limit or lower limit of other numerical ranges. In addition, the upper limit or lower limit of the numerical range recorded in the present disclosure can also be replaced by the value shown in the embodiment. It is also possible to select a certain numerical value from the numerical value of the upper limit and the numerical value of the lower limit recorded in stages in the present disclosure, respectively, and set it as the numerical range of stages. In addition, the numerical value of the upper limit and the numerical value of the lower limit recorded in the present disclosure can also be replaced by the value shown in the embodiment.

[0027] In the present disclosure, each component may contain a plurality of corresponding substances. When a plurality of corresponding substances exist in a composition, the content or content of each component refers to the total content or content of the plurality of substances present in the composition unless otherwise specified.

[0028] In the present disclosure, each structure in a polymer may also include multiple structures that match. When multiple structures that match each structure exist in a polymer, the content or content of each structure refers to the total content or content of the multiple structures present in the polymer unless otherwise specified.

[0029] The term "step" in the present disclosure includes not only steps that are independent of other steps but also steps that cannot be clearly distinguished from other steps as long as the intended effect of the step can be achieved.

[0030] The term "layer" in the present disclosure includes, when observing a region where the layer exists, not only a layer formed in the entire region but also a layer formed only in a part of the region.

[0031] <Method for producing polyamic acid-containing liquid>

[0032] The method for producing a polyamic acid-containing liquid includes obtaining a polyamic acid-containing liquid containing polyamic acid using a prepolymer-containing liquid containing an amic acid prepolymer, a diamine, and a tetracarboxylic dianhydride.

[0033] In some embodiments, the method for producing a polyamic acid-containing liquid includes: using a prepolymer-containing liquid 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 to obtain a polyamic acid-containing liquid. In the present disclosure, this production method is sometimes referred to as "production method R".

[0034] In other embodiments, the method for producing a polyamic acid-containing liquid includes: using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aliphatic or alicyclic diamine and a structure derived from tetracarboxylic dianhydride, a diamine, and tetracarboxylic dianhydride to obtain a polyamic acid-containing liquid. In the present disclosure, this production method is sometimes referred to as "production method L".

[0035] Polyamic acid is usually synthesized by addition condensation, that is, polymerization of diamine and tetracarboxylic dianhydride. In the polymerization of aromatic diamine and tetracarboxylic dianhydride, the reaction is generally carried out easily at room temperature. However, in the polymerization of diamine and tetracarboxylic dianhydride containing aliphatic or alicyclic diamine, there is a problem of generating precipitates and being difficult to react. The alkalinity of aliphatic or alicyclic diamines is quite high compared with aromatic diamines. It is believed that the precipitate includes a salt formed by unreacted aliphatic or alicyclic diamines showing high alkalinity and carboxylic acid (that is, ring-opened carboxylic dianhydride) produced in the process of addition condensation or polyamic acid having a carboxyl group obtained by addition condensation.

[0036] According to the present disclosure, even when the diamine contains an aliphatic or alicyclic diamine, the reaction can be carried out by suppressing the formation of salts or dissolving the formed salts or both by using a simple operation such as using an amic acid prepolymer, a diamine and a tetracarboxylic dianhydride. Thus, a polyamic acid-containing liquid containing a polyamic acid having a structure derived from an aliphatic or alicyclic diamine can be easily manufactured. In addition, according to several embodiments, a polyamic acid-containing liquid containing a polyamic acid at a high concentration can be manufactured in a short time.

[0037] [Manufacturing method R]

[0038] The manufacturing method R includes: using a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aromatic diamine and a structure derived from tetracarboxylic dianhydride, an aliphatic or alicyclic diamine, and tetracarboxylic dianhydride to obtain a polyamic acid-containing liquid (sometimes referred to as "step R2" in the present disclosure). The manufacturing method R may further include: preparing a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aromatic diamine and a structure derived from tetracarboxylic dianhydride (sometimes referred to as "step R1" in the present disclosure). In the present disclosure, tetracarboxylic dianhydride is sometimes 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 tetracarboxylic dianhydride is sometimes referred to as an "aromatic prepolymer", and a prepolymer-containing liquid containing an aromatic prepolymer is sometimes referred to as an "aromatic prepolymer-containing liquid". The manufacturing method R may include any steps other than step R1 and step R2.

[0039] According to the manufacturing method R, even when an aliphatic or alicyclic diamine is used, polymerization can be performed. One of the reasons is as follows. In the manufacturing 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 a salt with the aromatic prepolymer and the acid dianhydride, respectively. In the case where the composition of the polyamic acid to be obtained is the same, in the manufacturing method R, due to the formation of a salt of an aliphatic or alicyclic diamine and an aromatic prepolymer, the amount of the salt of an aliphatic or alicyclic diamine and an acid dianhydride is reduced compared to the case where an aromatic diamine and an aliphatic or alicyclic diamine and an acid dianhydride are used to obtain polyamic acid. The salt of an aromatic prepolymer is easily dissolved compared to the salt of an acid dianhydride due to the influence of the structure. In the manufacturing method R, a salt of an aromatic prepolymer that is easily soluble is formed, and the formation of a salt of an acid dianhydride that is difficult to dissolve is suppressed. That is, the 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, thereby enabling the polymerization reaction to proceed. However, the present invention is not limited to this assumption.

[0040] In step R1, an aromatic prepolymer-containing liquid is prepared. In some embodiments, in step R1, a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from an acid dianhydride can be used to prepare the aromatic prepolymer-containing liquid (step R1-s). Alternatively, in some embodiments, in step R1, an aromatic prepolymer-containing liquid containing an aromatic prepolymer can be obtained using an aromatic diamine, an acid dianhydride, and a solvent (step R1-i).

[0041] In step R2, an aromatic prepolymer containing liquid, an aliphatic or alicyclic diamine and an acid dianhydride are used to obtain a polyamic acid containing liquid. Aromatic diamines may also be further used. For example, in step R2, an aliphatic or alicyclic diamine and an acid dianhydride may be added to an aromatic prepolymer containing liquid to obtain a polyamic acid containing liquid (step R2-a). An aliphatic or alicyclic diamine, an acid dianhydride, and then an aromatic diamine may also be added to an aromatic prepolymer containing liquid. In the method of adding only one of an aliphatic or alicyclic diamine or an acid dianhydride to an aromatic prepolymer containing liquid, it is difficult to carry out a polymerization reaction because it is easily affected by the moisture present in the reaction system or it is easy to generate insoluble salts.

[0042] Examples of the embodiment of the production method R include a production method Rs including steps R1-s and R2-a and a production method Ri including steps R1-i and R2-a. In the production method Ri, it is preferred that step R2-a is performed continuously with step R1-i.

[0043] In step R1-s, for example, a prepolymer-containing liquid prepared in advance and containing an amic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from an acid dianhydride can be directly used as the aromatic prepolymer-containing liquid used in step R2. Alternatively, in step R1-s, for example, the prepolymer-containing liquid prepared in advance can be diluted or concentrated as needed to adjust the concentration and used as the aromatic prepolymer-containing liquid used in step R2. The prepolymer-containing liquid prepared in advance and used in step R1-s can be, for example, a prepolymer-containing liquid prepared separately or a commercially available prepolymer-containing liquid. The prepolymer-containing liquid can be prepared by a known method for preparing a polyamic acid solution, a method for preparing a polyamic acid-containing liquid disclosed in the present invention, or the like.

[0044] As step R1-i, for example, the following method can be cited. First, an aromatic diamine is dissolved in a solvent to prepare an aromatic diamine solution. Then, an acid 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.

[0045] The acid dianhydride may be added to the aromatic diamine solution in one addition, or may be added to the aromatic diamine solution in two or more additions. The number of additions may be, for example, 10 or less, 7 or less, or 4 or less. The interval between each addition may be, for example, 5 or more minutes, or 10 or more minutes. The interval between each addition may be, for example, 120 or less minutes, 60 or less minutes, 30 or less minutes, or 15 or less minutes.

[0046] Aromatic diamines have low basicity and therefore are unlikely to form salts with acid dianhydrides. Therefore, in step R1-i, an aromatic prepolymer-containing liquid containing an aromatic prepolymer at a high concentration can be easily prepared.

[0047] As step R2-a, for example, the following method can be listed. First, an aliphatic or alicyclic diamine is dissolved in a solvent to prepare an aliphatic or alicyclic diamine solution. Then, the aliphatic or alicyclic diamine solution and the acid dianhydride are added to the aromatic prepolymer-containing liquid prepared in step R1, and stirred. The stirring time is, for example, more than 10 minutes, more than 1 hour, or more than 3 hours. The stirring time is, for example, less than 72 hours, less than 48 hours, less than 24 hours, less than 12 hours, or less than 5 hours. The stirring temperature is, for example, 10 to 50°C, 15 to 40°C, or 20 to 35°C. When a stirrer is used during stirring, the rotation speed is, for example, 50 to 2,000 min -1 、200~1,000min -1 , or 300~800min -1 .

[0048] Although it also varies depending on the amount of the aromatic prepolymer and the added aliphatic or alicyclic diamine and acid dianhydride, the method of addition, etc., the salt is usually precipitated by addition. The stirring time is preferably longer than the time required for the dissolution of the salt. On the other hand, from the viewpoint of manufacturing efficiency, the stirring time is preferably short. According to the manufacturing method R, since the salt can be dissolved in a short time, the polyamic acid-containing liquid can be efficiently manufactured. The higher the stirring temperature, the more the salt can be dissolved in a short time. Therefore, it is also possible to stir while heating. On the other hand, from the viewpoint of being able to easily manufacture, it is preferably stirred without heating. According to the manufacturing method R, since the salt can be dissolved in a short time without heating, the polyamic acid can be efficiently manufactured. If an additive such as acetic acid that can dissolve the salt is used, the salt can be dissolved in a short time. Therefore, it is also possible to stir in the presence of an additive that can dissolve the salt. On the other hand, from the viewpoint of being able to easily manufacture, it is preferably stirred without using an additive. According to the manufacturing method R, since the salt can be dissolved in a short time without using an additive, the polyamic acid can be efficiently manufactured.

[0049] The aliphatic or alicyclic diamine solution and the acid dianhydride can be added to the aromatic prepolymer-containing liquid at the same time, or they can be added separately. The aliphatic or alicyclic diamine solution, the acid dianhydride, or both the aliphatic or alicyclic diamine solution and the acid dianhydride can be added to the aromatic prepolymer-containing liquid in one amount, or the whole amount can be added to the aromatic prepolymer-containing liquid in two or more times. The number of times divided into two or more times is, for example, 10 times or less, 7 times or less, or 4 times or less. The interval between each time is, for example, 5 minutes or more, or 10 minutes or more. The interval between each time is, for example, 120 minutes or less, 60 minutes or less, 30 minutes or less, or 15 minutes or less. Alternatively, there is no particular limitation on the number of times divided into two or more times, and the solution can be added dropwise for a specified time or the solid can be added in small amounts. The specified time is, for example, 10 to 60 minutes. When both the aliphatic or alicyclic diamine solution and the acid dianhydride are added to the aromatic prepolymer-containing liquid in two or more portions, the number of portions may be the same or different.

[0050] In the aromatic prepolymer-containing liquid, an aliphatic or alicyclic diamine and an aromatic diamine may also be added. In this case, the aliphatic or alicyclic diamine and the aromatic diamine may be added to the aromatic prepolymer-containing liquid at the same time, or may be added separately. The aromatic diamine may be added to the aromatic prepolymer-containing liquid in its entirety at once, or may be added to the aromatic prepolymer-containing liquid in its entirety at least twice.

[0051] When the step R1-i and the step R2-a are performed continuously, it is preferred to start adding at least one of the aliphatic or alicyclic diamine solution and the acid dianhydride while continuing the stirring in the step R1-i or after stopping the stirring, for example, within 60 minutes. When the step R1-i and the step R2-a are performed continuously, the aliphatic or alicyclic diamine solution and the acid dianhydride may be added to the container in which the aromatic prepolymer-containing liquid is obtained in the step R1-i and stirred.

[0052] The aromatic prepolymer may contain any structure other than the structure derived from the aromatic diamine and the structure derived from the acid dianhydride. For example, the aromatic prepolymer may contain any structure derived from diamine, such as a structure derived from an aliphatic or alicyclic diamine. The content of the structure derived from the aromatic diamine is, for example, more than 50% by mass, 70% by mass or more, 90% by mass or more, or 100% by mass, based on the mass of all structures derived from diamine.

[0053] The mass average molecular weight of the aromatic prepolymer is preferably 500 to 80,000, more preferably 1,000 to 50,000, and further preferably 5,000 to 30,000. The mass average molecular weight may also 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 has a tendency to be easily soluble due to low crystallinity. When the mass average molecular weight is 80,000 or less, the viscosity can be prevented from becoming too high, and there is a tendency that the miscibility with the acid dianhydride and the aliphatic or alicyclic diamine becomes good and the dissolution rate of the salt becomes easy to increase. In the present disclosure, the mass average molecular weight can be measured by gel permeation chromatography (GPC) and converted using a standard curve of standard polystyrene. The mass average molecular weight can be specifically measured by the method described in the examples.

[0054] From the viewpoint of preventing the viscosity from becoming too high, the content of the aromatic prepolymer in the aromatic prepolymer-containing liquid is, for example, 30.0 mass % or less, 20.0 mass % or less, 12.0 mass % or less, or 8.0 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 content of the aromatic prepolymer is, for example, 3.0 mass % or more, 5.0 mass % or more, or 10.0 mass % or more, based on the mass of the aromatic prepolymer-containing liquid.

[0055] From the viewpoint of dissolving the salt in a short time, the mass ratio of the aromatic prepolymer used in the production method R is, for example, 10.0 mass % or more, 15.0 mass % or more, 20.0 mass % or more, 30.0 mass % or more, or 40.0 mass % or more relative to the mass of the obtained polyamic acid. Considering the usage amounts of the aliphatic or alicyclic diamine and the acid dianhydride, the mass ratio of the aromatic prepolymer is, for example, 70.0 mass % or less, 60 mass % or less, 50 mass % or less, 40 mass % or less, or 30 mass % or less relative to the mass of the polyamic acid.

[0056] In particular, when obtaining a polyamic acid-containing liquid having a high content of polyamic acid, the content of the aromatic prepolymer in the aromatic prepolymer-containing liquid 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 liquid. The content of the aromatic prepolymer 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 liquid.

[0057] In particular, when obtaining a polyamic acid-containing liquid having a high polyamic acid content, the mass ratio of the aromatic prepolymer used in the production method R to the mass of the obtained polyamic acid is, for example, 50.0 mass % or more, 65.0 mass % or more, or 65.0 mass % or more. Considering the amount of aliphatic or alicyclic diamine and acid dianhydride used, the mass ratio of the aromatic prepolymer to the mass of the polyamic acid is, for example, 90.0 mass % or less, 80 mass % or less, or 75.0 mass % or less.

[0058] The polyamic acid containing liquid obtained by manufacturing method R usually contains polyamic acid and solvent. The content of polyamic acid is not particularly limited, and can be set to a suitable content according to the purpose of the polyamic acid containing liquid. If manufacturing method R is utilized, it is possible to manufacture a polyamic acid containing liquid containing polyamic acid at a high content. The content of polyamic acid is based on the total mass of polyamic acid and solvent, for example, it can be 10.0 mass % or more, 15.0 mass % or more, 20.0 mass % or more, or 25.0 mass % or more. The content of polyamic acid is based on the total mass of polyamic acid and solvent, for example, it can be 50.0 mass % or less, 40.0 mass % or less, or 30.0 mass % or less.

[0059] The polyamic acid obtained by manufacturing method R at least includes a structure derived from an aromatic diamine, a structure derived from an aliphatic or alicyclic diamine, and a structure derived from an acid dianhydride. The polyamic acid may further include an arbitrary structure. In manufacturing method R, as long as monomers such as diamines and acid dianhydrides are selected and used according to the structure contained in the polyamic acid as the target. Preferred embodiments (such as types, content, etc.) of polyamic acid-containing liquid and the polyamic acid contained therein, and amines such as diamines, acid dianhydrides, and solvents that can be used in manufacturing method R are described below.

[0060] [Manufacturing method L]

[0061] The manufacturing method L includes: using a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride, a diamine, and an acid dianhydride to obtain a polyamic acid-containing liquid (sometimes referred to as "step L2" in the present disclosure). The manufacturing method L may further include: preparing a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride (sometimes referred to as "step L1" in the present disclosure). In the present disclosure, the amic acid prepolymer containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride is sometimes referred to as an "aliphatic or alicyclic prepolymer", and the prepolymer-containing liquid containing an aliphatic or alicyclic prepolymer is sometimes referred to as an "aliphatic or alicyclic prepolymer-containing liquid". The manufacturing method L may include any steps other than step L1 and step L2.

[0062] According to manufacturing method L, when aliphatic or alicyclic diamine is not used, since the salt of aliphatic or alicyclic diamine is not formed, polymerization can be performed. Alternatively, according to manufacturing method L, even when aliphatic or alicyclic diamine is used, polymerization can be performed. One of the reasons is as follows. In manufacturing method L, when diamine contains aliphatic or alicyclic diamine, aliphatic or alicyclic prepolymer and aliphatic or alicyclic diamine react with acid dianhydride to obtain polyamic acid. Aliphatic or alicyclic diamine and aliphatic or alicyclic prepolymer and acid dianhydride form salts respectively. In the case where the composition of the polyamic acid to be obtained is the same, in manufacturing method L, due to the formation of aliphatic or alicyclic diamine and aliphatic or alicyclic prepolymer salt, the amount of aliphatic or alicyclic diamine and acid dianhydride salt is reduced compared to the case where aliphatic or alicyclic diamine and acid dianhydride are used to obtain polyamic acid. The salt of aliphatic or alicyclic prepolymer is easily soluble compared with the salt of acid dianhydride due to the influence of the structure. In the manufacturing method L, the salt of aliphatic or alicyclic prepolymer that is easily soluble is formed, and the formation of the salt of acid dianhydride that is difficult to dissolve is suppressed. That is, the manufacturing method L is a method for promoting the dissolution of the entire salt by reducing the poorly soluble salt and including the easily soluble salt when the diamine contains aliphatic or alicyclic diamine, thereby enabling the polymerization reaction. However, the present invention is not limited to this speculation.

[0063] In step L1, an aliphatic or alicyclic prepolymer-containing liquid is prepared. In some embodiments, step L1 can use a prepolymer-containing liquid containing an amic acid prepolymer containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride to prepare an aliphatic or alicyclic prepolymer-containing liquid (step L1-s). Alternatively, in some embodiments, step L1 can use an aliphatic or alicyclic diamine, an acid dianhydride, and a solvent to obtain an aliphatic or alicyclic prepolymer-containing liquid (step L1-i).

[0064] In step L2, a liquid containing aliphatic or alicyclic prepolymer, a diamine and an acid dianhydride are used to obtain a liquid containing polyamic acid. The diamine may include one or both of an aliphatic or alicyclic diamine and an aromatic diamine. For example, in step L2, a diamine and an acid dianhydride may be added to an aliphatic or alicyclic prepolymer containing liquid to obtain a polyamic acid-containing liquid containing polyamic acid (step L2-a). As for the method of adding only one of a diamine or an acid dianhydride to an aliphatic or alicyclic prepolymer containing liquid, it is difficult to carry out a polymerization reaction because it is easily affected by the moisture present in the reaction system or easily generates insoluble salts.

[0065] Examples of the embodiment of the production method L include a production method Ls including steps L1-s and L2-a and a production method Li including steps L1-i and L2-a. In the production method Li, it is preferred that step L2-a is performed continuously with step L1-i.

[0066] The description of step R1-s, step R1-i, and step R2-a in the manufacturing method R can be applied to step L1-s, step L1-i, and step L2-a in the manufacturing method L, with necessary changes. For example, as the method, time, temperature, etc. in step L1-s, step L1-i, and step L2-a, the examples listed in step R1-s, step R1-i, and step R2-a can be used.

[0067] However, in step L1-i, from the perspective that aliphatic or alicyclic diamines easily form salts with acid dianhydrides, the amounts of aliphatic or alicyclic diamines, acid dianhydrides, and solvents used may be adjusted in a manner that prevents the precipitation of salts, thereby suppressing the concentration of the obtained aliphatic or alicyclic prepolymer-containing liquid to a relatively low level. The content of the aliphatic or alicyclic prepolymer is based on the mass of the aliphatic or alicyclic prepolymer-containing liquid, and is particularly preferably 15.0% by mass or less.

[0068] In step L2-a, when alicyclic or aliphatic diamine and aromatic diamine are added as diamines to a liquid containing an aliphatic or alicyclic prepolymer, it is preferred to add an alicyclic or aliphatic diamine solution and a solid aromatic diamine to the liquid containing an aliphatic or alicyclic prepolymer, or to add a solution containing an alicyclic or aliphatic diamine and an aromatic diamine.

[0069] The aliphatic or alicyclic prepolymer may contain any structure other than the structure derived from the aliphatic or alicyclic diamine and the structure derived from the acid dianhydride. For example, the aliphatic or alicyclic prepolymer may contain any structure derived from diamine, such as a structure derived from an aromatic diamine. The content of the structure derived from the aliphatic or alicyclic diamine 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 structures derived from diamines.

[0070] 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 further preferably 5,000 to 30,000. The mass average molecular weight may also 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 has a tendency to be easily soluble due to low crystallinity. When the mass average molecular weight is 80,000 or less, the viscosity can be prevented from becoming too high, and there is a tendency that the miscibility with the acid dianhydride and the diamine becomes good and the dissolution rate of the salt becomes easy to increase.

[0071] 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 liquid 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 liquid. 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 liquid.

[0072] From the viewpoint of dissolving the salt in a short time, the mass ratio of the aliphatic or alicyclic prepolymer used in the production method L is, for example, 10.0 mass % or more, 15.0 mass % or more, 20.0 mass % or more, 30.0 mass % or more, or 40.0 mass % or more relative to the mass of the obtained polyamic acid. Considering the usage amounts of the diamine and the acid dianhydride, the mass ratio of the aliphatic or alicyclic prepolymer is, for example, 70.0 mass % or less, 60 mass % or less, 50.0 mass % or less, 40.0 mass % or less, or 30.0 mass % or less relative to the mass of the polyamic acid.

[0073] The polyamic acid containing liquid obtained by manufacturing method L usually contains polyamic acid and solvent. The content of polyamic acid is not particularly limited, and can be set to a suitable content according to the purpose of the polyamic acid containing liquid. According to manufacturing method L, it is possible to manufacture a polyamic acid containing liquid containing polyamic acid at a high concentration. The content of polyamic acid is based on the mass of the polyamic acid containing liquid, for example, it can be 10.0 mass % or more, 15.0 mass % or more, 20.0 mass % or more, or 25.0 mass % or more. The content of polyamic acid is based on the mass of the polyamic acid containing liquid, for example, it can be 50.0 mass % or less, 40.0 mass % or less, or 30.0 mass % or less.

[0074] The polyamic acid obtained by the manufacturing method L at least includes a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride. The polyamic acid may further include any structure. For example, the polyamic acid may include any structure derived from a diamine, such as a structure derived from an aromatic diamine. In the manufacturing method L, it is sufficient to select and use monomers such as diamines and acid dianhydrides according to the structure contained in the polyamic acid as the target. The preferred embodiments (such as types, contents, etc.) of the polyamic acid-containing liquid and the polyamic acid contained therein, and amines such as diamines, acids such as acid dianhydrides, and solvents that can be used in the manufacturing method L are described below.

[0075] <Polyamic acid containing liquid>

[0076] The polyamic acid-containing liquid contains a polyamic acid and a solvent containing a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride. The polyamic acid may contain any structure such as a structure derived from an amine other than the structure derived from an aliphatic or alicyclic diamine, a structure derived from a carboxylic anhydride other than the structure derived from an acid dianhydride. The polyamic acid may further contain a structure derived from a diamine such as a structure derived from an aromatic diamine. The structure derived from an acid dianhydride preferably contains a structure derived from pyromellitic dianhydride.

[0077] The content of polyamic acid contained in the polyamic acid containing liquid is preferably large. If the content of polyamic acid is large, when the polyamic acid containing liquid is used, for example, to manufacture a film as a formed body, the amount of solvent volatilized is reduced, and a film with a more uniform film thickness in the surface is easily obtained. If the content of polyamic acid is large, the viscosity of the polyamic acid containing liquid can be increased, and a film with a large film thickness can be manufactured according to the purpose.

[0078] In some embodiments, the content of the components derived from amines and carboxylic anhydrides in the polyamic acid-containing liquid is, for example, 20.0% by mass or more, based on the mass of the polyamic acid-containing liquid. In some embodiments, the ratio of the mass of the components derived from amines and carboxylic anhydrides obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is, for example, 18.0% by mass or more. When one or both of the content and the ratio are large, there is a tendency to obtain a polyamic acid-containing liquid with high viscosity.

[0079] Examples of components derived from amines and carboxylic anhydrides (hereinafter sometimes referred to as "components derived from monomers") include polyamic acid, salts of aliphatic or alicyclic diamines and carboxylic acids, salts of aliphatic or alicyclic diamines and amic acid prepolymers, polyimides, etc. The component derived from monomers includes at least one selected from these.

[0080] In several embodiments, the content of polyamic acid in the polyamic acid containing liquid is based on the total mass of polyamic acid and solvent, for example, 20.0 mass % or more. In several embodiments, the mass of the polyimide obtained by heating the filtrate of the polyamic acid containing liquid relative to the mass of the polyamic acid containing liquid is, for example, 18.0 mass % or more. When one or both of the content and the ratio are large, there is a tendency to obtain good film-forming properties.

[0081] According to the manufacturing method of the polyamic acid containing liquid, precipitates such as salts derived from monomers are sometimes produced during the manufacturing process. When the precipitate is insoluble, it becomes residual as a solid in the polyamic acid containing liquid. The polyamic acid containing liquid preferably does not contain solids or has a small content rate when containing solids. If the polyamic acid containing liquid does not contain solids or has a small content rate, then when using the polyamic acid containing liquid, for example, to manufacture a film as a formed body, it is easy to obtain a uniform film with excellent surface flatness.

[0082] In some embodiments, the turbidity of the polyamic acid-containing liquid is, for example, 2.5 NTU (Nephelometric Turbidity Unit) or less. When the turbidity is small, there is a tendency to obtain good film-forming properties. If the content of solids in the polyamic acid-containing liquid is large, the turbidity usually increases.

[0083] In a preferred embodiment, the polyamic acid-containing liquid contains a polyamic acid having a structure derived from an aliphatic or alicyclic diamine and a structure derived from an acid dianhydride and a solvent, and satisfies at least one of the following (1) to (4). For example, the polyamic acid-containing liquid satisfies one or both of the following (1) and (2), or satisfies one or both of the following (3) or (4).

[0084] (1) The content of the component derived from amine and carboxylic anhydride is 20.0% by mass or more, and the turbidity is 2.5 NTU or less.

[0085] (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.

[0086] (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from amine and carboxylic anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0087] (4) The ratio of the mass of the polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0088] The content of the component derived from the monomer in the polyamic acid containing liquid is based on the mass of the polyamic acid containing liquid, preferably 20.0 mass %, 20.1 mass %, 20.2 mass %, 20.5 mass %, 21.0 mass %, 23.0 mass %, 25.0 mass %, or 25.1 mass %. The upper limit of the content of the component derived from the monomer in the polyamic acid is not particularly limited. The content of the component derived from the monomer is based on the mass of the polyamic acid containing liquid, for example, 50.0 mass %, 40.0 mass %, 30.0 mass %, 28.0 mass %, or 26.0 mass %.

[0089] The ratio of the component derived from the monomer obtained by heating the polyamic acid containing liquid is based on the mass of the polyamic acid containing liquid, preferably 18.0 mass %, 18.3 mass %, 18.5 mass %, 19.0 mass %, 20.0 mass %, 22.0 mass %, 22.5 mass %, 23.0 mass % or more, or 23.5 mass %. The upper limit of the ratio of the component derived from the monomer in the polyamic acid is not particularly limited. The ratio of the component derived from the monomer is based on the mass of the polyamic acid containing liquid, for example, 48.0 mass %, 38.0 mass %, 28.0 mass %, 26.0 mass % or 24.0 mass %.

[0090] The content and ratio of the components derived from the monomers can be adjusted by changing the amount of diamine, acid dianhydride and solvent used in the preparation of the polyamic acid-containing liquid. The content and ratio of the components derived from amines and carboxylic anhydrides can be measured by the method described in the examples. It should be noted that the calculation formula for correcting the water content can be adjusted as long as the type and average molecular weight of the monomer used are appropriately changed.

[0091] The content of polyamic acid is based on the mass of the polyamic acid containing liquid, preferably 20.0 mass %, 20.1 mass %, 20.2 mass %, 20.5 mass %, 21.0 mass %, 23.0 mass %, 25.0 mass %, or 25.1 mass %. The upper limit of the content of polyamic acid is not particularly limited. The content of polyamic acid is based on the mass of the polyamic acid containing liquid, for example, 50.0 mass %, 40.0 mass %, 30.0 mass %, 28.0 mass %, or 26.0 mass %.

[0092] The ratio of the polyimide obtained by heating the filtrate containing liquid of polyamic acid is based on the mass of liquid contained in polyamic acid, preferably 18.0 mass %, 18.3 mass %, 18.5 mass %, 19.0 mass %, 20.0 mass %, 22.0 mass %, 22.5 mass %, 23.0 mass % or more, or 23.5 mass %. The upper limit of the ratio of polyimide is not particularly limited. The ratio of polyimide is based on the mass of liquid contained in polyamic acid, for example, 48.0 mass %, 38.0 mass %, 28.0 mass %, 26.0 mass % or less, or 24.0 mass %.

[0093] The polyamic acid containing liquid with a large content of polyamic acid or a ratio of polyimide can be easily manufactured by the manufacturing method of the above-mentioned embodiment, for example. The content of polyamic acid and the ratio of polyimide can be measured using the filtrate obtained by filtering the polyamic acid containing liquid and removing solids such as salts derived from monomers. For filtration, a 150-mesh filter made of stainless steel can be used. The content of polyamic acid and the ratio of polyimide can be measured specifically by the method described in the embodiment. It should be noted that the calculation formula for correcting the amount of water can be used as long as the type and average molecular weight of the monomer used are appropriately changed.

[0094] The content of polyamic acid and the ratio of polyimide can be the content or ratio at the temperature when the polyamic acid-containing liquid is actually used. Alternatively, the temperature of the polyamic acid-containing liquid when these contents and ratios are obtained may be different from the temperature when the polyamic acid-containing liquid is actually used. These contents and ratios can be, for example, the content or ratio when the temperature of the polyamic acid-containing liquid is any one of 20 to 35°C, preferably the content or ratio when the temperature of the polyamic acid-containing liquid is 25°C. In this case, as long as the temperature of the polyamic acid-containing liquid is set to any one of 20 to 35°C (preferably 25°C) and filtered, the obtained filtrate can be used to measure the content or ratio.

[0095] The turbidity of the polyamic acid-containing liquid is preferably 2.5NTU or less, 2.0NTU or less, 1.5NTU or less, 1.0NTU or less, or 0.5NTU or less, or 0NTU. In the present disclosure, the turbidity is the turbidity based on the formazine standard solution measured by the transmission scattered light method. The turbidity can be specifically measured by the method described in the embodiment. Generally, the smaller the turbidity, the lower the content of solids such as salts. The turbidity can be the turbidity at the temperature when the polyamic acid-containing liquid is actually used. Alternatively, the temperature of the polyamic acid-containing liquid when the turbidity is calculated may be different from the temperature when the polyamic acid-containing liquid is actually used. The turbidity can be, for example, the turbidity when the temperature of the polyamic acid-containing liquid is any one of 20 to 35°C, preferably the turbidity when the temperature of the polyamic acid-containing liquid is 25°C.

[0096] The viscosity (ηinh) of the polyamic acid-containing liquid is preferably 0.3 dL / g or more, more preferably 0.5 dL / g or more, and further preferably 0.6 dL / g or more. The viscosity of the polyamic acid-containing liquid 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 liquid is a viscosity measured at 30° C. using an Oswald viscometer. Specifically, the viscosity can be measured by the method described in the examples.

[0097] The mass average molecular weight of the polyamic acid is preferably 5,000 to 130,000, more preferably 10,000 to 120,000, further 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.

[0098] In polyamic acid, the content of the structure derived from aliphatic or alicyclic diamine is based on the mass of all structures derived from diamine contained in polyamic acid, preferably 20 mass % or more, for example, 30 mass % or more, 50 mass % or more, 70 mass % or more, or 80 mass % or more, or 100 mass %. In the case of 20 mass % or more, there is a tendency to obtain excellent dielectric properties. The content of the structure derived from aliphatic or alicyclic diamine is based on the mass of all structures derived from diamine contained in polyamic acid, for example, 80 mass % or less, 60 mass % or less, 50 mass % or less, or 40 mass % or less.

[0099] In the polyamic acid, the content of the structure derived from the aromatic diamine is based on the mass of all the structures derived from the diamine contained in the polyamic acid, and is preferably 80% by mass or less, for example, 70% by mass or less, 50% by mass or less, 30% by mass or less, or 20% by mass or less, or 0% by mass. In the case where the polyamic acid contains a structure derived from the aromatic diamine, from the viewpoint of mechanical strength, the content of the structure derived from the aromatic diamine is based on the mass of all the structures derived from the diamine contained in the polyamic acid, and can be 20% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more.

[0100] In the polyamic acid, the content of the structure derived from pyromellitic dianhydride is preferably 50 mass % or more, for example 70 mass % or more, 85 mass % or more, or 100 mass %, based on the mass of all structures derived from acid dianhydride contained in the polyamic acid.

[0101] In the polyamic acid, the content of the structure derived from the aliphatic or alicyclic diamine is 20% by mass or more based on the mass of all the structures derived from the diamine contained in the polyamic acid, and the content of the structure derived from the acid dianhydride is preferably 50% by mass or more based on the mass of all the structures derived from the tetracarboxylic dianhydride contained in the polyamic acid. The molar ratio of the structure derived from the diamine to the structure derived from the acid dianhydride is, for example, 1.00:0.90 to 1.00:1.10, and preferably 1.00:0.95 to 1.00:1.05.

[0102] Examples of structures derived from diamines and structures derived from acid dianhydrides that may be included in polyamic acid are described below. The structure derived from aliphatic or alicyclic diamines preferably includes a structure derived from alicyclic diamines, and more preferably includes a structure derived from dimer diamines. In the case where polyamic acid includes a structure derived from dimer diamines, the dielectric constant and dielectric loss tangent of the polyimide can be reduced. Polyimides with low dielectric constants and dielectric loss tangents can suppress transmission losses, and are therefore suitable for applications such as substrates such as FPCs and high-frequency antennas.

[0103] The polyamic acid-containing liquid contains a solvent. The polyamic acid-containing liquid may contain any component other than the polyamic acid and the solvent. Examples of solvents that may be contained in the polyamic acid-containing liquid are described below. The solvent may be a polar organic solvent, preferably an amide-based solvent containing an amide bond.

[0104] The method for producing the polyamic acid-containing liquid is not particularly limited, but the production method of the above-described embodiment can be preferably used.

[0105] <Diamine>

[0106] The diamine usable in the method for producing the polyamic acid-containing liquid of the above embodiment and the diamine in the "structural unit derived from diamine" contained in the polyamic acid contained in the polyamic acid-containing liquid of the above embodiment may include aromatic diamine, aliphatic or alicyclic diamine, or both.

[0107] In the present disclosure, the aromatic diamine may be a diamine having at least one aromatic ring and two amino groups bonded to the at least one aromatic ring. When the aromatic diamine has two or more aromatic rings, the two or more aromatic rings may be the same as each other, or may be different from each other. When the 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. The aromatic diamine may further have at least one group selected from an aliphatic hydrocarbon group and an alicyclic hydrocarbon group.

[0108] In the present disclosure, the 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 conforming to the 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 the alicyclic hydrocarbon group. Both of the two amino groups may be bonded to the aliphatic hydrocarbon group or the alicyclic hydrocarbon group, or only one of the two amino groups may be bonded to the aliphatic or alicyclic diamine. In the case where 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 the same as each other, or may be different from each other. In the case where the 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 be bonded to different groups selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups. The amino group bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group has stronger basicity than the amino group bonded to an aromatic ring, and therefore easily forms a salt with a carboxylic acid.

[0109] Examples of aromatic diamines include 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 4,4'-(biphenyl-2,5-diylbisoxy)dianiline, 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, bis(4-(4-aminophenoxy)phenyl)propane, ) phenyl) sulfone, bis(4-(3-aminophenoxy) phenyl) sulfone, 1,3-bis(4-aminophenoxy) neopentane, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-bis(4-aminophenoxy) biphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, bis(4-amino-3-carboxyphenyl) methane, 4,4'-diaminodiphenyl sulfone, 3,3'-di Aminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, N-(4-aminophenoxy)-4-aminoaniline, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, bis(3-aminophenyl) sulfone, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether, 5-trifluoromethyl-1,3-phenylenediamine, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl) diamines having an aromatic hydrocarbon group or an aromatic heterocyclic group, such as 2,2-bis[4-{4-amino-2-(trifluoromethyl)phenoxy}phenyl]hexafluoropropane, 2-trifluoromethyl-p-phenylenediamine, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 4,4'-(9-fluorenylidene)diphenylamine, 2,7-diaminofluorene, 1,5-diaminonaphthalene and 3,7-diamino-2,8-dimethyldibenzothiophene 5,5-dioxide.

[0110] Examples of aliphatic or alicyclic diamines include:

[0111] Diamines having a saturated aliphatic hydrocarbon group 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;

[0112] Diamines having an unsaturated aliphatic hydrocarbon group such as 1,9-diaminononene, 1,10-diaminodecene, 1,11-diaminoundecene, 1,12-diaminododecene, 1,14-diaminotetradecene, and 1,16-diaminohexadecene;

[0113] 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'-diaminodi Cyclohexylmethane, 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, 2,2-bis(3-methyl diamines having a saturated aliphatic hydrocarbon group such as 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;

[0114] Diamines having an unsaturated alicyclic hydrocarbon group, such as bis(aminomethyl)norbornene and 4,4'-diaminodicyclohexenylmethane;

[0115] Diamines derived from monounsaturated fatty acids such as crotonic acid, myristic 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; dimers (also called dimer acids) of unsaturated fatty acids such as triunsaturated fatty acids such as linolenic acid, pinolenic acid, elaeolic acid, mead acid, dihomo-γ-linolenic acid, and eicosatrienoic acid; and dimer diamines such as hydrogenated diamines obtained by hydrogenating carbon-carbon double bonds contained in the molecules of these diamines.

[0116] From the viewpoint of reducing the dielectric constant, the diamine preferably includes an alicyclic diamine. In particular, the diamine more preferably includes at least one selected from dimer diamines (unhydrogenated dimer diamines and hydrogenated dimer diamines). In the case where the polyamic acid includes a structure derived from dimer diamine, 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.

[0117] In polyamic acid, the content of the structure derived from aliphatic or alicyclic diamine is based on the mass of all structures derived from diamine contained in polyamic acid, preferably 20% by mass or more. More preferably, 30% by mass or more, 50% by mass or more, 70% by mass or more, or 90% by mass or more, or 100% by mass. The content of the structure derived from aliphatic or alicyclic diamine is based on the mass of all structures derived from diamine contained in polyamic acid, and is less than 100% by mass, for example, less than 90% by mass, or less than 70% by mass.

[0118] <Tetracarboxylic dianhydride>

[0119] The tetracarboxylic dianhydride usable in the method for producing the polyamic acid-containing liquid of the above-mentioned embodiment and the tetracarboxylic dianhydride in the “structural unit derived from tetracarboxylic dianhydride” contained in the polyamic acid contained in the polyamic acid-containing liquid of the above-mentioned embodiment may include aromatic tetracarboxylic dianhydride, aliphatic or alicyclic tetracarboxylic dianhydride, or both thereof.

[0120] In the present disclosure, the aromatic tetracarboxylic dianhydride may be a compound having at least one aromatic ring and two anhydride groups bonded to at least one aromatic ring. When the aromatic tetracarboxylic dianhydride has two or more aromatic rings, the two or more aromatic rings may be the same as each other, or may be different from each other. When the aromatic tetracarboxylic dianhydride has two or more aromatic rings, the two anhydride groups may be bonded to one aromatic ring, or the two anhydride groups may be bonded to different aromatic rings. The aromatic tetracarboxylic dianhydride may further have at least one group selected from an aliphatic hydrocarbon group and an alicyclic hydrocarbon group.

[0121] In the present disclosure, the aliphatic or alicyclic tetracarboxylic dianhydride may be a diamine having at least one group selected from aliphatic hydrocarbon groups and alicyclic hydrocarbon groups and two anhydride groups and not corresponding to aromatic tetracarboxylic dianhydride. The aliphatic or alicyclic tetracarboxylic dianhydride may further have at least one aromatic ring.

[0122] Examples of the aromatic tetracarboxylic dianhydride 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, 2,2 ...ethane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 2,2-bis(3, 3-dicarboxyphenyl) propane dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride, bis(3,4-dicarboxyphenyl) ether dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4-(p-phenylenedioxy)diphthalic dianhydride, 4,4-(m-phenylenedioxy)diphthalic dianhydride 2,2',6,6'-biphenyltetracarboxylic 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 dianhydride, 4,4'-(hexafluorophenyl) Tetracarboxylic dianhydrides having an aromatic hydrocarbon group include tetracarboxylic dianhydrides such as 1,2,5,6-naphthalene dicarboxylic dianhydride, 1,4,5,8-naphthalene dicarboxylic dianhydride, 2,3,6,7-naphthalene dicarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride and 1,2,7,8-phenanthrene tetracarboxylic dianhydride.

[0123] Examples of aliphatic or alicyclic tetracarboxylic dianhydrides include:

[0124] Tetracarboxylic dianhydrides having a saturated aliphatic hydrocarbon group, such as ethylenetetracarboxylic dianhydride and butanetetracarboxylic dianhydride;

[0125] Tetracarboxylic dianhydrides having a saturated alicyclic hydrocarbon group, such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride;

[0126] 1,1-bis(2,3-dicarboxycyclohexyl)ethane dianhydride, bis(2,3-dicarboxycyclohexyl)methane dianhydride, bis(3,4-dicarboxycyclohexyl)methane dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic 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'-bicyclohexyltetracarboxylic dianhydride Tetracarboxylic dianhydrides having an alicyclic hydrocarbon group such as hexyltetracarboxylic dianhydride, 1,2,5,6-decahydronaphthalene dicarboxylic dianhydride, 1,4,5,8-decahydronaphthalene dicarboxylic dianhydride, 2,3,6,7-decahydronaphthalene dicarboxylic dianhydride, octahydrobiphenylene-4a,8b:4b,8a-tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, and 5-(2,5-dioxotetrahydrofuranyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride.

[0127] In the polyamic acid, the tetracarboxylic dianhydride preferably contains aromatic tetracarboxylic dianhydride. In particular, the tetracarboxylic dianhydride preferably contains at least one selected from the group consisting of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0128] The content of the structure derived from pyromellitic dianhydride is preferably 50% by mass or more based on the mass of the structure derived from tetracarboxylic dianhydride contained in the above-mentioned polyamic acid. More preferably, it is 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, or 100% by mass. The content of the structure derived from pyromellitic dianhydride is 100% by mass or less based on the mass of the structure derived from tetracarboxylic dianhydride contained in the polyamic acid, for example, 90% by mass or less, or 70% by mass or less.

[0129] <Other monomers>

[0130] In the manufacturing method of the polyamic acid containing liquid of the above-mentioned embodiment, any monomer such as amine other than diamine and acid anhydride other than tetracarboxylic dianhydride can be used. The polyamic acid contained in the polyamic acid containing liquid of the above-mentioned embodiment can contain any structure such as the structure derived from amine other than diamine and the structure derived from acid anhydride other than tetracarboxylic dianhydride. As examples of amines, diamines, monoamines, amines with more than three functions, etc. can be listed. As examples of acid anhydrides, tetracarboxylic dianhydride, dicarboxylic anhydride, tricarboxylic anhydride, etc. can be listed.

[0131] In the polyamic acid, the content of the structure derived from diamine is based on the mass of all the structures derived from amine contained in the polyamic acid, for example, 90% by mass or more, 95% by mass or more, or 100% by mass. In the polyamic acid, the content of the structure of tetracarboxylic dianhydride is based on the mass of all the structures derived from anhydride contained in the polyamic acid, for example, 90% by mass or more, 95% by mass or more, or 100% by mass.

[0132] <Solvent>

[0133] Examples of solvents that can be used in the method for producing the polyamic acid-containing liquid of the above-mentioned embodiment and solvents that can be contained in the polyamic acid-containing liquid of the above-mentioned embodiment include polar organic solvents such as N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), 3-methoxy-N,N-dimethylpropaneamide (MPA), N,N'-dimethylformamide, N,N'-dimethylpropyleneurea [1,3-dimethyl-3,4,5,6-tetrahydropyrimidin-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-dimethylpropaneamide (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-dimethylpropaneamide (MPA) and dimethylacetamide (DMAc).

[0134] <Polyamic acid-containing liquid for insulating materials, heat-resistant insulating materials, or printed circuit boards>

[0135] The polyamic acid-containing liquid can be preferably used as an insulator composition, a heat-resistant insulator composition, or a printed circuit board composition. These compositions can further contain polyamide, polyethersulfone, acrylic polymer, epoxy compound, isocyanate compound, melamine compound, filler, defoamer, preservative, surfactant and other arbitrary components according to the application. The composition can be manufactured, for example, by mixing and stirring the polyamic acid-containing liquid with any component used as needed. The content of polyamic acid can be set to a range suitable for the application of the composition. The content of polyamic acid is based on the mass of the composition, for example, 5 to 30 mass%, 8 to 25 mass%, or 10 to 23 mass%.

[0136] <Polyimide>

[0137] Polyimide can be obtained by dehydration cyclization of polyamic acid (sometimes referred to as "imidization"). The method for producing polyimide includes: obtaining polyimide using a polyamic acid-containing liquid. The imidization method is not particularly limited. From the perspective of simplicity, a method of heating the polyamic acid-containing liquid can be preferably used. The heating temperature is, for example, 250 to 400°C.

[0138] <Molded body, insulator, or heat-resistant insulator>

[0139] Polyamic acid can be used to manufacture molded bodies, insulators and heat-resistant insulators. The manufacturing method of molded bodies, insulators and heat-resistant insulators includes: using polyamic acid containing liquid to obtain them. There is no particular restriction on the shape of the molded body, insulator and heat-resistant insulator, and it can be a shape suitable for the purpose. For example, it can be a film, a plate, a film, a layer, etc. The molded body, insulator and heat-resistant insulator can be used for various electronic components and mechanical parts.

[0140] <Printed substrate>

[0141] Polyamic acid can be used to manufacture printed circuit boards. The method for manufacturing printed circuit boards includes: using a polyamic acid-containing liquid to obtain a printed circuit board. Examples of printed circuit boards include printed wiring boards and printed circuit boards. Examples of printed circuit boards include flexible substrates and rigid substrates. Examples of printed circuit boards include single-sided substrates, double-sided substrates, and multilayer substrates. For example, polyamic acid-containing liquids can be used to obtain materials, protective films, insulating layers, etc. of these substrates.

[0142] Examples of flexible substrates include substrates having a base film and a base film obtained by using a polyamic acid-containing liquid. Other examples of flexible substrates include substrates having a base film and a heat-resistant insulating layer formed on the base film and at least a heat-resistant insulating layer obtained by using a polyamic acid-containing liquid.

[0143] <Example of Implementation>

[0144] Preferred examples of the embodiments of the present invention are listed below. The embodiments of the present invention are not limited to the following examples.

[0145] [1] A method for producing a polyamic acid-containing liquid, comprising: obtaining a polyamic acid-containing liquid containing polyamic acid using a prepolymer-containing liquid containing an amic acid prepolymer, a diamine, and a tetracarboxylic acid. In the present disclosure, the amic acid prepolymer is a polyamic acid containing a structure derived from a diamine and a structure derived from a tetracarboxylic acid.

[0146] [2] The method for producing a polyamic acid-containing liquid according to [1] above, comprising any one of the following steps (1) or (2).

[0147] (1) A polyamic acid-containing liquid containing a polyamic acid is obtained using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride, an aliphatic or alicyclic diamine, and tetracarboxylic dianhydride.

[0148] (2) A polyamic acid-containing liquid containing a polyamic acid is obtained using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aliphatic or alicyclic diamine and a structure derived from tetracarboxylic dianhydride, a diamine, and tetracarboxylic dianhydride.

[0149] Preferred embodiments of the above step (1) include the following [3] to

[10] . Preferred embodiments of the above step (2) include the following

[11] to

[17] .

[0150] The obtained polyamic acid is preferably any one of the following

[18] to

[31] .

[0151] [3] A method for producing a polyamic acid-containing liquid, comprising: obtaining a polyamic acid-containing liquid containing polyamic acid using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride, an aliphatic or alicyclic diamine, and tetracarboxylic dianhydride.

[0152] [4] The method for producing a polyamic acid-containing liquid according to [3], comprising: obtaining the prepolymer-containing liquid using an aromatic diamine, tetracarboxylic dianhydride and a solvent; and

[0153] The polyamic acid-containing liquid is obtained by adding the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid.

[0154] [5] The 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 portions.

[0155] [6] The method for producing a polyamic acid-containing liquid according to any one of [3] to [5], wherein the content of the amic acid prepolymer in the prepolymer-containing liquid is 30.0% by mass or less.

[0156] [7] The method for producing a polyamic acid-containing liquid according to any one of [3] to [6], wherein the mass of the amic acid prepolymer is 10.0% by mass or more relative to the mass of the polyamic acid.

[0157] [8] The method for producing a polyamic acid-containing liquid according to any one of [3] to [7] above, wherein the content of the amic acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or more, and the mass of the amic acid prepolymer is 50.0% by mass or more relative to the mass of the polyamic acid.

[0158] [9] The method for producing a polyamic acid-containing liquid according to any one of [3] to [8], wherein the amic acid prepolymer further includes a structure derived from an aliphatic or alicyclic diamine.

[0159]

[10] A method for producing a polyamic acid-containing liquid, which satisfies any one of the above-mentioned embodiments [3] to [9] and any one of the following embodiments

[18] to

[31] .

[0160]

[11] A method for producing a polyamic acid-containing liquid, comprising: using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aliphatic or alicyclic diamine and a structure derived from tetracarboxylic dianhydride, a diamine, and tetracarboxylic dianhydride to obtain a polyamic acid-containing liquid.

[0161]

[12] The method for producing a polyamic acid-containing liquid according to

[11] , comprising: obtaining the prepolymer-containing liquid using an aliphatic or alicyclic diamine, tetracarboxylic dianhydride and a solvent; and

[0162] The polyamic acid-containing liquid is obtained by adding the diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid.

[0163]

[13] The 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 portions.

[0164]

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

[11] to

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

[0165]

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

[11] to

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

[0166]

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

[11] to

[15] , wherein the amic acid prepolymer further includes a structure derived from an aromatic diamine.

[0167]

[17] A method for producing a polyamic acid-containing liquid, which satisfies any one of the above-mentioned embodiments

[11] to

[16] and any one of the following embodiments

[18] to

[31] .

[0168]

[18] A polyamic acid-containing liquid comprising a polyamic acid having a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent,

[0169] Satisfies one or both of the following (1) and (2).

[0170] (1) The content of the component derived from amine and carboxylic anhydride is 20.0% by mass or more, and the turbidity is 2.5 NTU or less.

[0171] (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.

[0172]

[19] The polyamic acid-containing liquid according to

[18] above, which satisfies the above (1).

[0173]

[20] The polyamic acid-containing liquid according to

[18] or

[19] above, which satisfies the above (2).

[0174]

[21] A polyamic acid-containing liquid comprising a polyamic acid having a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent,

[0175] Satisfy one or both of the following (3) and (4).

[0176] (3) The turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from amine and carboxylic anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0177] (4) The ratio of the mass of the polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

[0178]

[22] The polyamic acid-containing liquid according to

[21] , which satisfies the above (3). The polyamic acid-containing liquid may further satisfy any one of

[18] to

[20] .

[0179]

[23] The polyamic acid-containing liquid according to

[21] or

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

[18] to

[20] .

[0180]

[24] The polyamic acid-containing liquid according to any one of

[18] to

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

[0181]

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

[18] to

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

[0182]

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

[18] to

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

[0183]

[27] The polyamic acid-containing liquid according to

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

[0184]

[28] The polyamic acid-containing liquid according to any one of

[24] to

[27] , wherein the content of the structure derived from the aliphatic or alicyclic diamine is 20% by mass or more based on the mass of all the structures derived from the diamine contained in the polyamic acid,

[0185] The content of the structure derived from pyromellitic dianhydride is 50% by mass or more based on the mass of all the structures derived from tetracarboxylic dianhydride contained in the polyamic acid.

[0186]

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

[18] to

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

[0187]

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

[18] to

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

[0188]

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

[18] to

[30] , which is used for an insulating material, a heat-resistant insulating material, or a printed circuit board.

[0189]

[32] A method for producing a polyimide, comprising obtaining a polyimide using the polyamic acid-containing liquid according to any one of

[18] to

[31] above.

[0190]

[33] A method for producing a molded article, comprising: obtaining a molded article using the polyamic acid-containing liquid according to any one of

[18] to

[31] above.

[0191]

[34] A method for producing a printed circuit board, comprising: obtaining a printed circuit board using the polyamic acid-containing liquid according to any one of

[18] to

[31] above.

[0192] Example

[0193] The embodiments of the present invention will be specifically described by way of examples. However, the embodiments of the present invention are not limited to the following examples.

[0194] The abbreviations used in the examples are shown below.

[0195] PMDA: Pyromellitic Dianhydride

[0196] ODA: Oxydiphenylamine

[0197] PACM: p-Diaminodicyclohexylmethane

[0198] NBDA: Norbornanediamine

[0199] DDA: dimer diamine (molecular weight 534.99, "PRIAMINE1075", Croda Japan Co., Ltd.)

[0200] DMAc: dimethylacetamide

[0201] <Preparation and evaluation of polyamic acid-containing liquid (1)>

[0202] A polyamic acid-containing liquid was prepared using the production method Rs or the production method Ls, and the evaluation was performed.

[0203] [Example 1]

[0204] In aeration device, in 50mL spiral tube, prepare the amic acid prepolymer containing the amic acid prepolymer (0.586g) shown in the table 1 and the dehydration DMAc (4.696g) and contain liquid. Then, ODA (0.295g, 1.47mmol), PACM (0.575g, 2.73mmol) and dehydration DMAc (4.683g) are dropped into the sample bottle, stirred, and prepared diamine solution. The amic acid prepolymer contains the whole amount of adding diamine solution and PMDA (0.910g, 0.417mmol) in liquid, at room temperature, stir for 24 hours, obtain polyamic acid and contain liquid 1.

[0205] [Example 2]

[0206] In ventilator, in 50mL spiral tube, prepare the amic acid prepolymer containing the amic acid prepolymer (0.588g) shown in the table 1 and dehydration DMAc (4.694g) and contain liquid.Then, PACM (0.863g, 4.10mmol) and dehydration DMAc (4.683g) are dropped into the sample bottle, stir, and prepare diamine solution. The amic acid prepolymer contains the whole amount of adding diamine solution and PMDA (0.900g, 0.410mmol) in liquid, at room temperature stirred 8 hours, obtained polyamic acid and contained liquid 2.

[0207] [Example 3]

[0208] In aeration device, in 50mL spiral tube, prepare the amic acid prepolymer containing the amic acid prepolymer (0.588g) shown in the table 1 and the amic acid prepolymer of dehydration DMAc (4.694g) and contain liquid.Then, PACM (0.863g, 4.10mmol) and dehydration DMAc (4.683g) are dropped into sample bottle, stirred, and diamine solution is prepared.Afterwards, diamine solution and PMDA (0.900g, 4.10mmol) are respectively divided into 4 equal parts, while the amic acid prepolymer is stirred, every 10 minutes is divided into 4 times and added to the amic acid prepolymer and contain liquid, at room temperature, stir for 8 hours in total, obtain polyamic acid and contain liquid 3.The stirring time is the time from the 1st addition to the end of stirring.

[0209] [Example 4]

[0210] In aeration device, in 50mL spiral tube, prepare the amic acid prepolymer containing the amic acid prepolymer (0.586g) shown in Table 1 and dehydration DMAc (7.027g) containing liquid. Then, ODA (0.575g, 2.87mmol), PACM (0.288g, 1.37mmol) and dehydration DMAc (2.342g) are dropped into sample bottle, stirred, and diamine solution is prepared. Afterwards, in amic acid prepolymer containing liquid, add diamine solution and PMDA (0.923g, 4.23mmol) total amount, at room temperature stirred 3 hours, obtain polyamic acid containing liquid 4.

[0211] [Example 5]

[0212] In ventilator, in 50mL spiral tube, prepare the amic acid prepolymer containing the amic acid prepolymer (0.360g) shown in the table 1 and dehydration DMAc (6.123g) and contain liquid. Then, ODA (0.575g, 2.87mmol), PACM (0.400g, 1.90mmol) and dehydration DMAc (3.278g) are dropped into the sample bottle, stirred, and prepared diamine solution. The amic acid prepolymer contains the whole amount of adding diamine solution and PMDA (1.04g, 4.77mmol) in liquid, at room temperature stirred 24 hours, obtained polyamic acid and contained liquid 5.

[0213] [Method for measuring content, turbidity, etc. of polyamic acid]

[0214] The content of polyamic acid, turbidity of the polyamic acid-containing liquid, etc. were measured by the following method. The measurement results are shown in Table 1. Since the precipitates generated during the polymerization reaction dissolved in the polyamic acid-containing liquids of Examples 1 to 5, no solid residue was recovered by filtration.

[0215] (Polyamic acid content ((2) in the table))

[0216] The content of the polyamic acid is measured by the following procedure.

[0217] The polyamic acid-containing liquid (25°C) is filtered under pressure using a stainless steel mesh (150 mesh, "Stainless Steel Mesh #150" (material: SUS316, mesh number: 150, wire diameter: 0.06mm, mesh: 0.109mm, opening rate: 41.6%, weaving method: plain weave), Tantore Co., Ltd.), and the solid residue is removed to obtain a polyamic acid solution as a filtrate. 1.5g (initial mass) is measured from the polyamic acid solution using a high-precision electronic balance and added to an aluminum dish. The polyamic acid solution added to the aluminum dish is heated at 200°C for 2 hours to volatilize the solvent, and the polyamic acid is dehydrated and ring-closed to obtain polyimide. The value obtained by measuring the polyimide with a high-precision electronic balance is set as the mass after heating. The NV2 value (mass %) (Nonvolatile content) is obtained by dividing the mass after heating by 1.5g (initial mass) and multiplying by 100. The amount of water reduced by the dehydration cyclization reaction of polyamic acid is corrected by the following calculation formula to obtain the content of polyamic acid. The average molecular weight of diamine is calculated using the molecular weight and molar fraction of each diamine in the structure derived from "diamine" contained in polyamic acid. The average molecular weight of tetracarboxylic dianhydride is calculated using the molecular weight and molar fraction of each tetracarboxylic dianhydride in the structure derived from "tetracarboxylic dianhydride" contained in polyamic acid.

[0218] Polyamic acid content (mass %) =

[0219] 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}

[0220] (Content ratio of components derived from amine and carboxylic anhydride ((1) in the table))

[0221] The NV1 value (mass %) is obtained by the same procedure as above (content of polyamic acid), except that the unfiltered polyamic acid-containing liquid is heated. The NV1 value (mass %) is used in the above calculation formula instead of the NV2 value (mass %), and the average molecular weight of the diamines in the components derived from amines and carboxylic anhydrides contained in the polyamic acid-containing liquid and the average molecular weight of the tetracarboxylic dianhydride are used to obtain the content of the components derived from amines and carboxylic anhydrides relative to the mass of the polyamic acid-containing liquid.

[0222] (Ratio of the mass of polyimide ((4) in the table))

[0223] The NV2 value (mass %) obtained above is defined as the ratio of the mass of the polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid.

[0224] (Content ratio of components derived from amine and carboxylic anhydride after heating ((3) in the table))

[0225] The NV1 value (mass %) obtained above is defined as the ratio of the mass of the components derived from amine and carboxylic anhydride obtained by heating the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid.

[0226] (Turbidity)

[0227] Turbidity was measured using a transmission scattered light method and was determined based on a calibration curve using a formazin standard solution. The measurement conditions are shown below.

[0228] Measuring device: Spectrophotometer "COH400" (Nippon Denshoku Industries Co., Ltd.)

[0229] Light source: tungsten lamp, color temperature 2500 degrees (absolute temperature)

[0230] Cell size (optical path length): 10mm

[0231] Acceptance angle relative to incident light: 90±30°

[0232] Peak of sensitivity characteristics: 500nm

[0233] Sample temperature: 25°C

[0234] (Viscosity)

[0235] The viscosity (ηinh) was measured using an Oswald viscometer in a thermostatic bath KINEMATIC VISCOSITY BATH TV-5S (THOMAS KAGAKU CO., LTD.) The polyamic acid was dissolved in DMAc to a concentration of 0.5 g / dL to prepare a sample, and the flow time was measured at 30°C.

[0236] (Mass average molecular weight)

[0237] The mass average molecular weight was measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene. The calibration curve was approximated by a cubic equation using a set of five samples of standard polystyrene ("TSK standard POLYSTYRENE", Tosoh Corporation). The GPC conditions are shown below.

[0238] GPC device: High-efficiency GPC device "HLC-8320GPC" (Tosoh Corporation)

[0239] Detector: Ultraviolet absorption detector "UV-8320" (Tosoh Corporation)

[0240] Column: "Gelpack GL-S300MDT-5" (2 columns in total) (Showa Denko Materials Co., Ltd.)

[0241] Eluent: THF / DMF=1 / 1 (volume ratio)+LiBr(0.06mol / L)+H3PO4(0.06mol / L)

[0242] Flow rate: 1mL / min

[0243] Column size: 8mm I.D.×300mm

[0244] Sample concentration: 5mg / 1mL

[0245] Injection volume: 5μL

[0246] Measurement temperature: 40℃

[0247] <Evaluation of polyamic acid-containing liquid>

[0248] (Film Production)

[0249] A film was produced by the following procedure using a polyamic acid-containing liquid (varnish).

[0250] The surface of a commercially available glass substrate is degreased with acetone, and a film applicator with a film thickness adjustment function is used to apply a varnish of polyamic acid in such a way that the film thickness after imidization becomes 25 μm. The applied varnish is pre-dried at 80° C. for 60 minutes using a hot plate (heating plate) to form a layer of polyamic acid. Next, the layer of polyamic acid is heated at 350° C. for 1 hour in a nitrogen atmosphere using an inert gas oven to obtain a film 1 of polyimide. After the glass substrate formed with the film is immersed in warm water for about 15 minutes, the film 1 is peeled off from the glass substrate.

[0251] Furthermore, a polyimide film 2 was obtained by the same procedure as above except that the polyamic acid-containing liquid (varnish) was applied so that the film thickness after imidization would be 50 μm, and the film 2 was peeled from the glass substrate.

[0252] (Relative dielectric constant and dielectric loss tangent)

[0253] The film 1 was cut into 60 mm × 60 mm size, dried at 125°C for 1 hour, and then measured immediately. The dielectric properties (dielectric constant Dk and dielectric loss tangent Df) of the film were measured by the cavity resonator method (TE mode). For the measurement, a compact USB vector network analyzer ("MS46122B", ANRITSU Corporation) was used. The conditions were set at a frequency of 10 GHz and a measurement temperature of 25°C.

[0254] (Film-forming property)

[0255] Film 1 and Film 2 were cut into 140 mm long x 70 mm wide, and the film thickness was measured at 15 points (5 points long and 3 points wide at intervals of 20 to 30 mm) using a high-precision digital micrometer ("MDH-25MB", Mitutoyo Co., Ltd.), and evaluated according to the following criteria.

[0256] ◎: When coating was performed so that the film thickness after imidization was 50 μm, the variation in the in-plane distribution of the film thickness was within 50 μm±3 μm (that is, the film thickness at all 15 points was 47 to 53 μm.)

[0257] ○: When coating is performed so that the film thickness after imidization becomes 25 μm, the variation in the in-plane distribution of the film thickness is within 25 μm±3 μm (that is, the film thickness at all 15 points is 22 to 28 μm.)

[0258] ×: When coating is performed so that the film thickness after imidization becomes 25 μm, the unevenness of the film thickness distribution in the plane is greater than 25 μm±3 μm (that is, the film thickness at one or more points is less than 22 μm or greater than 28 μm).

[0259]

[0260] <Preparation and evaluation of polyamic acid-containing liquid (2)>

[0261] A polyamic acid-containing liquid was prepared using the production method Ri or the production method Li, and the evaluation was performed.

[0262] [Example 6]

[0263] In ventilation device, ODA (0.575g, 2.87mmol), PMDA (0.586g, 2.67mmol) and dehydration DMAc (7.025g) are dropped into 50mL spiral tube, stirred 1 hour. In addition, PACM (0.575g, 2.73mmol) and dehydration DMAc (2.342g) are dropped into sample bottle, stirred, and prepared diamine solution. Afterwards, in spiral tube, drop into the whole amount of diamine solution and PMDA (0.637g, 2.92mmol), at room temperature, add up to stirring in 24 hours, obtain polyamic acid and contain liquid 6.

[0264] [Example 7]

[0265] ODA (0.626 g, 3.13 mmol), PMDA (0.634 g, 2.91 mmol) and dehydrated DMAc (9.366 g) were put into a 50 mL spiral tube in a ventilation device and stirred for 1 hour. In addition, NBDA (0.626 g, 4.06 mmol) and dehydrated DMAc (1.873 g) were put into a sample bottle and stirred to prepare a diamine solution. Afterwards, the total amount of diamine solution and PMDA (0.933 g, 4.28 mmol) was put into the spiral tube and stirred for a total of 8 hours at room temperature to obtain a polyamic acid-containing liquid 7.

[0266] [Example 8]

[0267] In aeration device, ODA (0.870g, 4.34mmol), PMDA (0.220g, 1.01mmol) and dehydration DMAc (7.025g) are dropped into 50mL spiral tube, stirred 1 hour. In addition, DDA (0.378g, 0.71mmol) and dehydration DMAc (2.342g) are dropped into sample bottle, stirred, and prepared diamine solution. Afterwards, in spiral tube, drop into the whole amount of diamine solution and PMDA (0.881g, 4.04mmol), at room temperature, add up to 8 hours stirring, thus obtain polyamic acid containing liquid 8.

[0268] [Example 9]

[0269] In a ventilator, ODA (0.703g, 3.51mmol), PMDA (0.204g, 0.94mmol) and dehydration DMAc (7.025g) are dropped into a 50mL spiral tube, stirred for 1 hour. In addition, DDA (0.626g, 1.17mmol) and dehydration DMAc (2.342g) are dropped into a sample bottle, stirred, and diamine solution is prepared. Afterwards, in a spiral tube, diamine solution and PMDA (0.817g, the whole amount of 3.74mmol) are dropped into, at room temperature, stirred for 3 hours, thus obtaining polyamic acid containing liquid 9.

[0270] [Example 10]

[0271] In aeration device, ODA (0.402g, 2.01mmol), PMDA (0.175g, 0.80mmol) and dehydration DMAc (7.025g) are dropped into 50mL spiral tube, stirred 1 hour. In addition, DDA (1.073g, 2.01mmol) and dehydration DMAc (2.342g) are dropped into sample bottle, stirred, and prepared diamine solution. Afterwards, in spiral tube, drop into the whole amount of diamine solution and PMDA (0.700g, 3.21mmol), at room temperature add up to stirring in 3 hours, thus obtain polyamic acid and contain liquid 10.

[0272] [Example 11]

[0273] In a ventilator, ODA (0.288g, 1.44mmol), PACM (0.288g, 1.37mmol), PMDA (0.613g, 2.81mmol) and dehydration DMAc (8.429g) are dropped into a 50mL spiral tube, stirred for 1 hour. In addition, PACM (0.288g, 1.37mmol) and dehydration DMAc (0.937g) are dropped into a sample bottle, stirred, and diamine solution is prepared. Afterwards, in a spiral tube, diamine solution, ODA (0.288g, 1.44mmol) and PMDA (0.610g, 2.80mmol) are dropped into the whole amount, stirred for 8 hours at room temperature, thus obtaining polyamic acid containing liquid 11.

[0274] [Example 12]

[0275] In a ventilation device, PACM (0.575 g, 2.73 mmol), PMDA (0.596 g, 2.73 mmol) and dehydrated DMAc (9.366 g) were put into a 50 mL spiral tube and stirred for 1 hour. Then, the total amount of ODA (0.575 g, 2.87 mmol) and PMDA (0.627 g, 2.87 mmol) were put into the spiral tube and stirred for 3 hours at room temperature to obtain a polyamic acid-containing liquid 12.

[0276] [Example 13]

[0277] In ventilation device, PACM (0.575g, 2.73mmol), PMDA (0.596g, 2.73mmol) and dehydration DMAc (8.429g) are dropped into 50mL spiral tube, stirred 1 hour. In addition, PACM (0.288g, 1.37mmol) and dehydration DMAc (0.937g) are dropped into sample bottle, stirred, and prepared diamine solution. Afterwards, in spiral tube, drop into the whole amount of diamine solution, ODA (0.288g, 1.44mmol) and PMDA (0.627g, 2.87mmol), at room temperature, add up to 8 hours stirring, thus obtain polyamic acid and contain liquid 13.

[0278] [Example 14]

[0279] In a ventilator, PACM (0.577g, 2.74mmol), PMDA (0.598g, 2.74mmol) and dehydration DMAc (8.429g) are dropped into a 50mL spiral tube, stirred for 1 hour. In addition, PACM (0.577g, 2.74mmol) and DMAc (0.937g) are dropped into a sample bottle, stirred, and diamine solution is prepared. Afterwards, in a spiral tube, the whole amount of diamine solution and PMDA (0.637g, 2.92mmol) is dropped into, at room temperature, stirred for 8 hours, thus obtaining polyamic acid containing liquid 14.

[0280] [Example 15]

[0281] In aeration device, PACM (0.288g, 1.37mmol) and dehydration DMAc (4.683g) are dropped into 50mL spiral tube, stirred, and prepared diamine solution 1. Then, PMDA (0.300g, 1.37mmol) is added in diamine solution 1, stirred for 10 minutes. In addition, PACM (0.863g, 4.10mmol) and dehydration DMAc (4.683g) are dropped into sample bottle, stirred, and prepared diamine solution 2. Afterwards, PMDA (0.900g, 4.10mmol) and diamine solution 2 are divided into 3 equal parts respectively, while stirring in spiral tube, every 10 minutes is divided into 3 times and added to spiral tube, at room temperature, stirred for 8 hours in total, and obtained polyamic acid containing liquid 15. The stirring time is the time from the 1st addition to the end of stirring.

[0282] [Example 16]

[0283] NBDA (0.575 g, 3.73 mmol), PMDA (0.586 g, 2.69 mmol) and dehydrated DMAc (8.429 g) were placed in a 50 mL spiral tube in a ventilation device and stirred for 1 hour. In addition, PACM (0.575 g, 2.73 mmol) and dehydrated DMAc (0.937 g) were placed in a sample bottle to prepare a diamine solution. After that, the diamine solution and PMDA (0.637 g, 2.92 mmol) were added to the spiral tube 2 times and 3 times every 10 minutes, respectively, and stirred for a total of 8 hours at room temperature to obtain a polyamic acid solution 16. The diamine solution was divided into 2 equal parts and divided into 2 times, and PMDA was divided into 3 times at a ratio of 5:4:1.

[0284] [Comparative Example 1]

[0285] PACM (1.151 g, 5.47 mmol) and dehydrated DMAc (9.366 g) were put into a 50 mL spiral tube in a ventilation device to prepare a diamine solution. Afterwards, PMDA (1.195 g, 5.48 mmol) was added in 4 portions every 10 minutes. After addition, the mixture was stirred at room temperature for a total of 24 hours to obtain a polyamic acid-containing liquid.

[0286] [Comparative Example 2]

[0287] PACM (0.342 g, 1.62 mmol) and dehydrated DMAc (9.366 g) were placed in a 50 mL spiral tube in a ventilation device to prepare a diamine solution. After that, the total amount of ODA (0.797 g, 3.98 mmol) and PMDA (1.221 g, 5.60 mmol) were added. After the addition, the mixture was stirred at room temperature for a total of 24 hours to obtain a polyamic acid-containing liquid.

[0288] [Method for measuring content, turbidity, etc. of polyamic acid]

[0289] The measurement was performed in the same manner as in Preparation and Evaluation of Polyamic Acid-Containing Liquid (1). The measurement results are shown in Tables 2-1 to 2-3. In the polyamic acid-containing liquids of Examples 6 to 16, no solid residue was recovered by filtration because the precipitate generated during the polymerization reaction was dissolved.

[0290] <Evaluation of polyamic acid-containing liquid>

[0291] Evaluation was performed in the same manner as in Preparation and Evaluation of Polyamic Acid-Containing Liquid (1). The evaluation results are shown in Table 2. In addition, in Comparative Examples 1 and 2, films could not be produced using the polyamic acid-containing liquid.

[0292]

[0293]

[0294]

[0295] <Preparation and evaluation of polyamic acid-containing liquid (3)>

[0296] [Example 17]

[0297] (Preparation of polyamic acid-containing liquid 17a)

[0298] The polyamic acid-containing liquid 17a was prepared using the production method Ri.

[0299] ODA (24.5 g, 0.122 mol), PMDA (7.11 g, 0.033 mol) and dehydrated DMAc (300.0 g) were put into a 500 mL three-necked flask in a ventilation device and stirred for 1 hour. In addition, DDA (21.8 g, 0.041 mol) and dehydrated DMAc (20.0 g) were put into a sample bottle and stirred to prepare diamine solution a. Afterwards, the total amount of diamine solution a and PMDA (26.6 g, 0.122 mol) was put into a spiral tube and stirred for a total of 8 hours at room temperature to obtain a polyamic acid-containing liquid 17a.

[0300] (Preparation of polyamic acid-containing liquid 17b)

[0301] The polyamic acid-containing liquid 17a is used as the aromatic prepolymer-containing liquid, and the polyamic acid-containing liquid 17b is prepared by the production method Rs.

[0302] ODA (10.2 g, 0.051 mol) and PMDA (2.97 g, 0.014 mol) were added to a 500 mL three-necked flask containing polyamic acid liquid 17a, and stirred for 1 hour. In addition, DDA (9.10 g, 0.017 mol) and dehydrated DMAc (18.2 g) were added to a sample bottle and stirred to prepare diamine solution b. Afterwards, the total amount of diamine solution b and PMDA (11.1 g, 0.051 mol) was added to a spiral tube, and stirred for a total of 8 hours at room temperature to obtain polyamic acid liquid 17b.

[0303] [Method for measuring the content, turbidity, etc. of polyamic acid]

[0304] The viscosity was measured in the same manner as in Preparation and Evaluation of Polyamic Acid-Containing Liquid (1) except that the viscosity was measured by the following method. The measurement results are shown in Table 3. In the polyamic acid-containing liquid of Example 17, no solid residue was recovered by filtration because the precipitate generated during the polymerization reaction was dissolved.

[0305] (Viscosity)

[0306] The viscosity was measured using a rotary B-type viscometer ("TVB-10M", Toki Sangyo Co., Ltd.) at a temperature of the polyamic acid-containing liquid of 30° C. using a No. 3 rotor.

[0307] <Evaluation of polyamic acid-containing liquid>

[0308] The evaluation results are shown in Table 3.

[0309]

Claims

1. A method for producing a polyamic acid-containing liquid, comprising the steps of obtaining a polyamic acid-containing liquid using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aromatic diamine and a structure derived from a tetracarboxylic dianhydride, an aliphatic or alicyclic diamine, and a tetracarboxylic dianhydride.

2. The method for producing a polyamic acid-containing liquid according to claim 1, wherein The method comprises the following steps: using aromatic diamine, tetracarboxylic dianhydride and a solvent to obtain the prepolymer-containing liquid; and The polyamic acid-containing liquid is obtained by adding the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid.

3. The method for producing a polyamic acid-containing liquid according to claim 1 or 2, wherein: The method comprises the step of adding one or both of the aliphatic or alicyclic diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more portions.

4. The method for producing a polyamic acid-containing liquid according to any one of claims 1 to 3, wherein The content of the amic acid prepolymer in the prepolymer-containing liquid is 30.0% by mass or less.

5. The method for producing a polyamic acid-containing liquid according to any one of claims 1 to 4, wherein The ratio of the mass of the amic acid prepolymer to the mass of the polyamic acid is 10.0 mass % or more.

6. The method for producing a polyamic acid-containing liquid according to any one of claims 1 to 5, wherein The content of the amic acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or more, and the mass of the amic acid prepolymer is 50.0% by mass or more relative to the mass of the polyamic acid.

7. The method for producing a polyamic acid-containing liquid according to any one of claims 1 to 6, wherein The amic acid prepolymer further includes a structure derived from an aliphatic or alicyclic diamine.

8. A method for producing a polyamic acid-containing liquid, comprising the steps of obtaining a polyamic acid-containing liquid using a prepolymer-containing liquid containing an amic acid prepolymer having a structure derived from an aliphatic or alicyclic diamine and a structure derived from tetracarboxylic dianhydride, a diamine, and tetracarboxylic dianhydride.

9. The method for producing a polyamic acid-containing liquid according to claim 8, wherein: The method comprises the following steps: obtaining the prepolymer-containing liquid by using an aliphatic or alicyclic diamine, a tetracarboxylic dianhydride and a solvent; and The polyamic acid-containing liquid is obtained by adding the diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid.

10. The method for producing a polyamic acid-containing liquid according to claim 8 or 9, wherein: The method comprises the step of adding one or both of the diamine and the tetracarboxylic dianhydride to the prepolymer-containing liquid in two or more portions.

11. The method for producing a polyamic acid-containing liquid according to any one of claims 8 to 10, wherein The content of the amic acid prepolymer in the prepolymer-containing liquid is 15.0% by mass or less.

12. The method for producing a polyamic acid-containing liquid according to any one of claims 8 to 11, wherein The ratio of the mass of the amic acid prepolymer to the mass of the polyamic acid is 10.0 mass % or more.

13. The method for producing a polyamic acid-containing liquid according to any one of claims 8 to 12, wherein The amic acid prepolymer further includes a structure derived from an aromatic diamine.

14. A polyamic acid-containing liquid comprising a polyamic acid having a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent, Satisfies one or both of the following (1) and (2), (1) The content of components derived from amines and carboxylic 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.

15. The polyamic acid-containing liquid according to claim 14, wherein Satisfies the above (1).

16. The polyamic acid-containing liquid according to claim 14 or 15, wherein Satisfies the above (2).

17. A polyamic acid-containing liquid comprising a polyamic acid having a structure derived from an aliphatic or alicyclic diamine and a structure derived from a tetracarboxylic dianhydride, and a solvent, Satisfies one or both of the following (3) and (4), (3) the turbidity is 2.5 NTU or less, and the ratio of the mass of the components derived from amine and carboxylic 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 the polyimide obtained by heating the filtrate of the polyamic acid-containing liquid to the mass of the polyamic acid-containing liquid is 18.0 mass % or more.

18. The polyamic acid-containing liquid according to claim 17, wherein Satisfies the above (3).

19. The polyamic acid-containing liquid according to claim 17 or 18, wherein Satisfies the above (4).

20. The polyamic acid-containing liquid according to any one of claims 14 to 19, wherein The structure derived from tetracarboxylic dianhydride includes a structure derived from pyromellitic dianhydride.

21. The polyamic acid-containing liquid according to any one of claims 14 to 20, wherein The polyamic acid further includes a structure derived from an aromatic diamine.

22. The polyamic acid-containing liquid according to any one of claims 14 to 21, wherein The content of the structure derived from the aliphatic or alicyclic diamine is 20% by mass or more based on the mass of all the structures derived from the diamine contained in the polyamic acid.

23. The polyamic acid-containing liquid according to any one of claims 20 to 22, wherein The content of the structure derived from pyromellitic dianhydride is 50% by mass or more based on the mass of all structures derived from tetracarboxylic dianhydride contained in the polyamic acid.

24. The polyamic acid-containing liquid according to any one of claims 20 to 23, wherein The content of the structure derived from the aliphatic or alicyclic diamine is 20% by mass or more based on the mass of all the structures derived from the diamine contained in the polyamic acid. The content of the structure derived from pyromellitic dianhydride is 50% by mass or more based on the mass of all structures derived from tetracarboxylic dianhydride contained in the polyamic acid.

25. The polyamic acid-containing liquid according to any one of claims 14 to 24, wherein The structure derived from an aliphatic or alicyclic diamine includes a structure derived from an alicyclic diamine.

26. The polyamic acid-containing liquid according to any one of claims 14 to 25, wherein The structure derived from an aliphatic or alicyclic diamine includes a structure derived from a dimer diamine.

27. The polyamic acid-containing liquid according to any one of claims 14 to 26, wherein The polyamic acid-containing liquid is used for printing a substrate. 28 . A method for producing a polyimide, comprising the step of obtaining a polyimide using the polyamic acid-containing liquid according to claim 14 . 29 . A method for producing a molded article, comprising the step of obtaining a molded article using the polyamic acid-containing liquid according to claim 14 . 30 . A method for producing a printed circuit board, comprising the step of obtaining a printed circuit board using the polyamic acid-containing liquid according to claim 14 .

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