TW202039630A - Polyimide resin powder and method for producing polyimide resin powder - Google Patents

Abstract

The present invention provides a polyimide resin powder which is not susceptible to aggregation during preparation of a varnish, and which exhibits high solubility in a varnish. A polyimide resin powder which has a repose angle of 37.0 DEG or less, and which is configured such that if A ([mu]m) is the average perimeter and B ([mu]m2) is the average area of the particles of the polyimide resin powder as calculated by means of image analysis of the polyimide resin powder, the ratio of the square of A to B, namely A2/B is from 14.0 to 30.0.

Description

Polyimide resin powder and manufacturing method of polyimide resin powder

The present invention relates to a polyimide resin powder and a method for manufacturing the polyimide resin powder.

At present, image display devices such as liquid crystal display devices and organic EL display devices are not only used in televisions, but also widely used in various applications such as mobile phones and smart watches. Previously, as the front panel of such an image display device, glass has been used, but the glass is very rigid and easy to break, so it is difficult to be used as a front panel material for a flexible display.

Therefore, it is studied to use polymer materials as a material to replace glass. The panel tends to exhibit flexibility before the polymer material is included, so it can be expected to be used in various applications. Various resins having flexibility can be cited, for example, polyimide resins.

When using polyimide-based resins to manufacture polymer materials such as films, from the viewpoint of reducing the volume during transportation, manufacturing polyimide-based resins in powder form and transporting the powder to the film formation site , Use the polyimide resin varnish prepared by using the powder to form a film.

As a method for producing such polyimide resin powder, there are the following methods: using a polyimide resin containing a polyimide precursor or chemically imidizing the polyimide precursor A poor solvent such as methanol is added to the reaction liquid to precipitate polyimide-based resin powder (for example, Patent Document 1). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2018-28073

[The problem to be solved by the invention]

When producing a polyimide resin film using polyimide resin powder, the polyimide resin must be dissolved in a solvent to prepare a varnish. However, depending on the shape or surface characteristics of the polyimide resin powder, the polyimide resin powder may agglomerate and cause agglomeration during the preparation of the varnish, or it may not be able to obtain sufficient solubility in the varnish. Happening.

Therefore, the subject of the present invention is to provide a polyimide-based resin powder that is not easy to agglomerate when preparing a varnish and has high solubility in the varnish. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the inventors focused on the various characteristic values and shapes of the polyimide-based resin powder and the production conditions of the polyimide-based resin powder, and conducted intensive research. As a result, it was discovered that the polyimide resin powder having an angle of repose of 37.0° or less and the average perimeter and average area of the particles calculated by image analysis in a specific relationship solves the above-mentioned problems, thereby completing the present invention .

That is, the present invention includes the following preferable aspects. [1] A polyimide-based resin powder whose angle of repose is 37.0° or less. If the average perimeter of the particles of the polyimide-based resin powder calculated by image analysis is A μm, the average area Set as B μm ² , the ratio of the square of A to B (A ² /B) is 14.0-30.0. [2] The polyimide resin powder as described in [1] above, wherein the surface roughness of the particles of the polyimide resin powder calculated by image analysis is Ra μm and the average If the circle equivalent radius is set to Zc μm, the ratio of Ra to Zc (Ra/Zc) does not reach 0.19. [3] The polyimide-based resin powder as described in [1] or [2] above, wherein the average area of particles of the polyimide-based resin powder calculated by image analysis (B μm ² ) It is 2,000～500,000 μm ² . [4] The polyimide resin powder according to any one of [1] to [3] above, wherein the average circle equivalent of particles of the polyimide resin powder calculated by image analysis The radius (Zc μm) is 50 to 800 μm. [5] The polyimide resin powder according to any one of [1] to [4] above, wherein the weight average molecular weight of the polyimide resin is 200,000 or more. [6] The polyimide resin powder as described in any one of [1] to [5] above, wherein the chromaticity of the polyimide resin powder is based on the L ^* a ^* b ^* color system In the color difference measurement, satisfy L ^＊ ≧90, -10≦a ^＊ ≦10 and -10≦b ^＊ ≦10. [7] A method for producing polyimide resin powder, which at least includes the following steps: while dissolving the polyimide resin in a good solvent under the condition that the speed of the tip of the stirring blade is 3.40 m/sec or less The intermediate resin solution is stirred while adding at least one poor solvent to the resin solution to precipitate the polyimide resin. [8] The method for producing a polyimide resin powder according to the above [7], wherein the rotation speed of the stirring blade in the stirring is 100 rpm or less. [Effects of Invention]

The polyimide resin of the present invention is not easy to agglomerate during the preparation of the varnish and has high solubility in the varnish.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiment described here, and various changes can be made without departing from the scope of the present invention.

<Polyimide-based resin powder> The polyimide-based resin powder of the present invention has an angle of repose of 37.0° or less. If the polyimide-based resin powder has a particle size calculated by image analysis If the average perimeter is A μm and the average area is B μm ² , the ratio of the square of A to B (A ² /B) is 14.0-30.0. Here, in this specification, the so-called polyimide resin means selected from polyimide resin, polyimide imide resin, polyimide precursor resin, and polyimide imide precursor resin At least one resin in the group consisting of. The polyimide resin is a resin containing repeating structural units containing an amide group, and the polyimide resin is a resin containing repeating structural units containing both an amide group and an amide group. In addition, the polyimide precursor resin and the polyimide imide precursor resin provide the polyimide resin and the polyimide imide resin as a precursor for the imidization of the polyimide resin and the polyimide resin respectively through imidization. It is a resin also known as polyamide acid. In this specification, the above-mentioned polyimide precursor resin and the above-mentioned polyimide precursor resin are also collectively referred to as "polyimide resin".

The angle of repose of the polyimide resin powder of the present invention is 37.0° or less. When the angle of repose of the polyimide resin powder exceeds 37.0°, the fluidity of the polyimide resin powder during the preparation of the varnish is low, and it tends to exist in agglomerates. Therefore, for example, put it in the varnish solvent When polyimide-based resin powder is used, aggregates (lumps) of polyimide-based resin powder are likely to be generated. If an agglomerate of polyimide resin powder is generated during the production of the varnish, the polyimide resin powder existing on the surface of the agglomerate is swelled by the varnish solvent, but is present inside the agglomerate The polyimide resin powder is still in a powder state. As a result, the varnish solvent is less likely to penetrate from the surface of the aggregate to the inside, and the aggregate remains in the varnish. When using a varnish containing such agglomerates to manufacture an optical film, there are cases where the agglomerates remain in the optical film, which may impair the optical properties of the optical film. In addition, when an optical film is manufactured after passing the varnish through the filter, the filter may be clogged. In addition, by using a filter to remove agglomerates containing polyimide resin powder, the resin concentration in the varnish will be lower than the original intended concentration, and the resin concentration in the varnish of each manufacturing batch may be different. The issue of stability.

The angle of repose of the polyimide resin powder of the present invention is 37.0° or less, and from the viewpoint of easily suppressing the generation of agglomerates during the preparation of the varnish, it is preferably 36.0° or less. The lower limit of the angle of repose of the polyimide resin powder of the present invention is not particularly limited. It is usually about 25° or more. From the viewpoint of workability such as picking, it is preferably 27° or more, and more Preferably, it is 30° or more. The angle of repose can be measured using a powder property evaluation device (for example, a powder tester PT-X from Hosokawa Micron Co., Ltd.), and can be measured, for example, by the method described in the examples.

It is believed that the angle of repose is affected by the particle shape, particle size, and surface properties of the polyimide resin powder. As a method of setting the angle of repose within the above-mentioned range, a method of producing polyimide-based resin powder by the production method of the present invention described later can be cited. It is believed that when a poor solvent is added to a resin solution containing a polyimide resin to precipitate the polyimide resin powder, the polyimide resin is precipitated as fine primary particles, and the primary particles may become secondary depending on the situation. The particles and tertiary particles agglomerate and become polyimide resin powder. When the stirring speed of stirring the resin solution is too fast, the particle size of the primary particles tends to be further reduced. Therefore, the surfaces of secondary particles and tertiary particles tend to have fine irregularities. As a result, it is considered that the obtained polyimide-based resin powder tends to have a larger angle of repose. In addition, it is considered that when a poor solvent is added to the polyimide-based resin solution to precipitate the polyimide-based resin powder, the precipitation rate of the polyimide-based resin powder is relatively high (specifically, to the polyimide-based resin powder). When the poor solvent added to the imine-based resin solution is added at a faster rate, when a poor solvent with low solubility for polyimine-based resin is used, and/or when the precipitation temperature is lowered, polyamide The imine-based resin is likely to precipitate as fine primary particles, and there is also a tendency for the angle of repose to increase. In addition, it is believed that when the precipitation rate of the polyimide resin powder is relatively fast, impurities are likely to be mixed into the polyimide resin powder. In this case, it is considered that there is a problem on the surface of the polyimide resin powder. The smoothness decreases and the angle of repose increases. Therefore, by controlling these conditions, the angle of repose of the polyimide-based resin powder can be adjusted to a desired range.

If the average perimeter of the particles calculated by image analysis for the polyimide resin powder of the present invention is A μm and the average area is B μm ² , then the ratio of the square of A to B (A ² /B) is 14.0～30.0. The ratio calculated from A ² /B is related to the amount of concavities and convexities that can be visualized by image analysis. When the value of the ratio is larger, it means that there are many concavities and convexities that can be visualized by image analysis. When the ratio (A ² /B) is less than 14.0, it is considered that the solubility of the polyimide resin powder in the varnish is insufficient. In addition, when the ratio (A ² /B) exceeds 30.0, the polyimide resin powders are likely to aggregate with each other. For example, when the polyimide resin powder is put into the varnish solvent, the polyimide resin powder is likely to be produced. Agglomerates (agglomerates) of resin powder. From the standpoint that it is easy to improve the solubility of the polyimide resin powder in the varnish, and it is easy to inhibit the aggregation of the polyimide resin powder, the ratio (A ² /B) is preferably 16-28 , More preferably 18-25.

It is considered that when the ratio (A ² /B) is 14.0 to 30.0, the polyimide-based resin powder has moderately concavities and convexities that can be seen by image analysis. It is considered that when the ratio (A ² /B) is less than 14.0, the polyimide-based resin powder has too few concavities and convexities that can be seen by image analysis. Therefore, the polyimide-based resin powder After the body is put into the varnish solvent, the contact area between the polyimide-based resin powder and the varnish solvent becomes small, and the solubility is insufficient. On the other hand, it is considered that when the ratio (A ² /B) exceeds 30.0, the polyimide-based resin powder has too many irregularities that can be seen by image analysis. Therefore, the polyimide-based resin powder The agglomeration between the particles of the body becomes higher, and when the polyimide-based resin powder is put into the varnish solvent, the particles are not easily disintegrated to produce agglomerates. When the ratio (A ² /B) is 14.0 to 30.0, agglomerates are not easily generated, and the contact area between the varnish solvent and the resin powder can be sufficiently ensured, and the solubility can be improved.

As a method of adjusting the ratio (A ² /B) to the above-mentioned range, a method of producing a polyimide-based resin powder by the production method of the present invention described later can be cited. It is believed that the ratio (A ² /B), like the angle of repose, tends to increase when the stirring speed of the resin solution is too fast when the resin powder is precipitated. Therefore, it can be adjusted by adjusting the stirring conditions. To the required range above.

The polyimide-based resin powder of the present invention can be observed with an optical microscope, and the obtained image can be analyzed by the method described below to determine the average perimeter (A μm) and average area (B μm ² ), and the surface roughness (Ra μm) and average circle equivalent radius (Zc μm) described later. The particle image analysis method will be described with reference to FIG. 1.

Observe the polyimide resin powder with an optical microscope, and obtain an optical microscope image of the particles with a pixel size of 3 μm/pixel or less. The observation magnification can be appropriately selected according to the particle diameter (equivalent circle radius, etc.) of the polyimide-based resin powder, which can grasp the shape of the particles and the magnification of the concavity and convexity. It is not particularly limited. It is preferably at least 50 times Magnification observation. Secondly, transfer the obtained optical microscope image to a computer and use image analysis software for processing. As a method of processing using image analysis software, first, if necessary, smoothing and/or shadow correction are performed on the optical microscope image. Then, the optical microscope image is grayed out, and binarized based on a specific threshold (for example, the middle value of the maximum brightness and the minimum brightness in the image) to obtain a binarized image. At this time, visually checking the binary image, it was confirmed that the area corresponding to the particle image of the polyimide-based resin powder was successfully separated from the other areas. In the case of unclear separation, adjust the threshold for binarization. In this way, the binary image of the particle is obtained. For example, the image shown in (a) in Figure 1 is obtained. Based on the image, the perimeter and area are measured by the particle analysis of the image analysis software. The measurement of the perimeter and area is preferably carried out for more than 50 particles, more preferably more than 100 particles, and the average value can be used as the average perimeter (A μm) and average area (B μm ² ) of the particles. As image analysis software, you can choose Image J or Photoshop.

Furthermore, for the binary image of the particle ((a) in Fig. 1), a barycenter-surface distance curve is obtained ((c) in Fig. 1). As a method of obtaining the center of gravity-surface distance curve, specifically, first, for the binarized image of one particle image, the center of gravity (1 point) and the points on the surface of the particle (a plurality of points) are respectively obtained. Furthermore, the so-called point on the surface of the particle refers to the point on the outline of the particle image in the binary image. Then, any one point on the surface is set as the starting point, and the distance between the starting point and the center of gravity (the distance between the center of gravity and the surface) is measured. Secondly, the point on the surface adjacent to the right side of the starting point from the observation of the center of gravity is set as the secondary point, and the distance between the starting point and the secondary point, the secondary point and the center of gravity (the distance between the center of gravity and the surface) is calculated. Similarly, the point on the surface adjacent to the right side of the secondary point from the observation of the center of gravity is set as the secondary point, and the distance between the secondary point and the secondary point, and the distance between the secondary point and the center of gravity (the distance between the center of gravity and the surface) is calculated. This operation is repeated until it returns to the starting point. In this way, for a plurality of points on the surface of the particle, the distance between the point and the adjacent point and the distance between the point and the center of gravity (center of gravity-distance between the surface) are calculated. In this case, the distance from the starting point to a specific point i on the surface is defined as the sum of the distances that pass through the adjacent surfaces one by one from the starting point until the point i is reached. For the results obtained for a plurality of points on the surface, the distance from the starting point is the horizontal axis, and the distance between the point of the surface and the center of gravity (center of gravity-the distance between the surface) is the vertical axis. Carry out the drawing to obtain the graph (center of gravity-distance curve between surfaces) as shown in (c) in Figure 1.

According to the center of gravity-surface distance curve obtained by the above method for one particle, a reference circle corresponding to the surface (contour) of the particle is set. Specifically, the average value of the distance between the center of gravity and the surface is set to Zc', and a circle with the center of gravity as the center and the radius of Zc' is set as the reference circle ((b) in FIG. 1). The radius of the reference circle set in the above manner, that is, the average value (Zc' μm) of the distance between the center of gravity and the surface is set as the circle equivalent radius of one particle. In addition, when the number of points on the measured surface is set to n, and the distance between the i-th point and the center of gravity (center of gravity-distance between the surface) is set to Z(i) μm, the following formula ( 1) Calculate the surface roughness (Ra' μm) of the one particle. [Number 1]

The above measurement is performed on a plurality of particles (preferably 50 or more, more preferably 100 or more particles), and the equivalent circle radius (Zc' μm) of each particle obtained and the surface roughness (Ra' The average value of μm is set as the average circle equivalent radius of the particles (Zc μm) and the surface roughness of the particles (Ra μm). In addition, the ratio (Ra/Zc) is calculated from the average circle equivalent radius of the particles (Zc μm) and the surface roughness (Ra μm) of the particles.

In the polyimide resin powder of the present invention, as described above, it is considered that the primary particles become secondary particles depending on the situation, and the tertiary particles agglomerate to form individual particles in the polyimide resin powder. For example, when the primary particles agglomerate to form secondary particles, the surface of the primary particles may also have irregularities, and the surface of the secondary particles may have irregularities caused by the size and shape of the primary particles. In this case, it is considered that the above-mentioned angle of repose is affected by both the unevenness on the surface of the primary particle and the unevenness on the surface of the secondary particle. Furthermore, it is considered that the aforementioned angle of repose is affected by various factors such as the state of the functional groups on the surface of the primary particles and the amount of impurities contained in the polyimide-based resin powder. On the other hand, the ratio (A ² /B) is related to the amount of irregularities that can be seen by image analysis as described above. Depending on the size or shape of the primary particles and secondary particles, the irregularities on the surface of the primary particles will not The influence ratio (A ² /B), but there is also the influence ratio of the unevenness of the secondary particle surface (A ² /B). Therefore, in the polyimide resin powder of the present invention, it is important that the angle of repose is 37.0° or less and the ratio (A ² /B) is 14.0 to 30.0.

The average perimeter (A μm) of particles calculated by image analysis of the polyimide resin powder of the present invention is preferably 200-3,500 μm, more preferably 300-2,500 μm, and still more preferably 500 ~2,000 μm, more preferably 750-1,500 μm. When the average perimeter is above the above lower limit, the powder is not easy to fly and the operability is easy to improve. When the average circumference is below the above upper limit, the solubility in the solvent is easy to improve.

The average area of particles (B μm ² ) calculated by image analysis of the polyimide resin powder of the present invention is preferably 2,000-500,000 μm ² , more preferably 5,000-200,000 μm ² , and more preferably It is 8,000～100,000 μm ² . When the average area is above the above lower limit, the powder is not easy to fly, and the operability is easy to improve. When the average area is below the above upper limit, the solubility in the solvent is easy to improve.

If the surface roughness of the particles calculated by image analysis of the polyimide resin powder of the present invention is set to Ra μm, and the average circle equivalent radius is set to Zc μm, the ratio of Ra to Zc (Ra /Zc) From the viewpoint of easily suppressing aggregation of particles of the polyimide resin powder, it is preferably less than 0.19, and more preferably 0.18 or less. In addition, the lower limit of the ratio (Ra/Zc) is preferably 0.10 or more from the viewpoint of solubility in a solvent, more preferably 0.12 or more, and still more preferably 0.14 or more.

The surface roughness (Ra μm) of the particles calculated by image analysis of the polyimide resin powder of the present invention is preferably 5 to 120 μm, more preferably 10 to 80 μm, and still more preferably 12 ~50 μm. When the surface roughness of the particles is more than the above lower limit, the solubility in the solvent is likely to increase, and when the particle surface roughness is below the above upper limit, it is easy to suppress aggregation of the particles of the polyimide resin powder.

The average circle equivalent radius (Zc μm) calculated by image analysis of the polyimide resin powder of the present invention is preferably 50-800 μm, more preferably 80-500 μm, and still more preferably 100- 350 μm, particularly preferably 110-350 μm. When the particle equivalent radius is above the above lower limit, the powder is not easy to fly and the operability is easy to improve. When the particle is below the above upper limit, the solubility in the solvent is easy to improve.

The polyimide resin powder of the present invention preferably satisfies L ^* ≧90, -10≦a in the color difference measurement based on the L ^* a ^* b ^* color system (according to JIS Z 8781-4: 2013) ^＊ ≦10 and -10≦b ^＊ ≦10. In the above-mentioned color difference measurement, L ^* is preferably 90 or more, more preferably 93 or more, and even more preferably 95 or more from the viewpoint of easily improving the transparency and visibility of the polymer material finally obtained. The upper limit of L ^* is not particularly limited, as long as it is 100 or less. In the above color difference measurement, a ^* represents an index of redness. From the viewpoint of easily improving the visibility of the polymer material finally obtained, it is preferably -10 or more and 10 or less, more preferably -7 or more and 7 or less, and more Preferably, it is above -5 and below 5. In the above-mentioned color difference measurement, b ^* represents an index of blueness. From the viewpoint of easily improving the visibility of the polymer material finally obtained, it is preferably -10 or more and 10 or less, more preferably -5 or more and 10 or less, and further Preferably it is -3 or more and 8 or less. The above-mentioned color difference can be measured using a color difference meter, for example, by the method described in the examples.

The weight-average molecular weight of polyimide resin is easy to reduce the viewpoint of cohesiveness when preparing varnish from polyimide resin powder, and it is easy to increase the surface hardness of the film obtained by using polyimide resin powder. From the viewpoint of buckling resistance, in terms of standard polystyrene, it is preferably 200,000 or more, more preferably 250,000 or more, still more preferably 300,000 or more, still more preferably 350,000 or more, and particularly preferably 360,000 or more. The weight average molecular weight of the polyimide-based resin can easily improve the solubility of the polyimide-based resin powder in solvents, and it is easy to improve the extensibility of the film obtained by using the polyimide-based resin powder. From the viewpoint of workability, it is preferably 1,000,000 or less, more preferably 800,000 or less, still more preferably 700,000 or less, and particularly preferably 500,000 or less. The weight average molecular weight can be measured by, for example, GPC, and can be calculated by standard polystyrene conversion, and can be calculated, for example, by the method described in the examples.

<Method for producing polyimide resin powder> The method for producing polyimide resin powder of the present invention can obtain a powder having an angle of repose and ratio (A ² /B) within the above range. It is not particularly limited. For example, it can be produced by a method for producing polyimide resin powder at least including the following steps. The resin solution prepared by dissolving the amine resin in the good solvent is stirred, and at least one poor solvent is added to the resin solution to precipitate the polyimide resin. The present invention also provides a method for producing the above-mentioned polyimide resin powder.

The manufacturing method of the present invention includes at least the following steps: (1) While stirring the resin solution obtained by dissolving the polyimide resin in a good solvent under the condition that the speed at the tip of the stirring blade is 3.40 m/sec or less, add at least one type of defect to the resin solution The solvent causes the polyimide-based resin to precipitate. Hereinafter, this step is also referred to as "step (1)".

As long as the resin solution obtained by dissolving the polyimide-based resin in a good solvent is a solution in which the polyimide-based resin is dissolved in the good solvent, the production method and the like are not particularly limited. The resin solution can be a reaction solution obtained by polymerizing monomers in a solvent, which is a good solvent for polyimide resins, or dissolving the isolated polyimide resin The solution obtained in a good solvent. From the viewpoint of easy production of the polyimide-based resin solution, it is preferable to perform the polymerization reaction of the monomers in a good solvent described later, and use the obtained reaction solution as the polyimide-based resin solution.

The good solvent contained in the polyimide resin solution refers to a solvent that easily dissolves the polyimide resin. For example, the solubility of the polyimide resin at room temperature (20-30°C) is 1% by mass The above solvent. The good solvent contained in the polyimide resin solution may be one solvent or a mixture of two or more solvents. As a good solvent, for example, acetone, N,N-dimethylformamide (DMF), dimethyl sulfide (DMSO), γ-butyrolactone (GBL), N,N-dimethyl ethyl Diamide (DMAc). The solubility of the good solvent to the polyimide resin is preferably 3% by mass or more, more preferably 5% by mass or more from the viewpoint of volumetric efficiency. The upper limit of the solubility of the good solvent to the polyimide resin is not particularly limited. From the viewpoint of reducing the amount of poor solvent used, it is preferably 40% by mass or less, and more preferably 25% by mass or less.

In terms of the content of the good solvent in the polyimide resin solution, it is preferably 60% by mass or more relative to the total amount of the polyimide resin solution from the viewpoint of easy adjustment to a viscosity that is easy to handle in operation. Preferably, it is 75% by mass or more. In addition, the content of the good solvent in the polyimide-based resin solution can reduce the amount of poor solvent used, relative to the total amount of the polyimide-based resin solution, preferably 98% by mass or less, and more Preferably, it is 95% by mass or less.

The content of the polyimide resin in the polyimide resin solution is, from the viewpoint of volumetric efficiency, relative to the total amount of the polyimide resin solution, preferably 1% by mass or more, more preferably 3 Above mass%. In addition, the content of the polyimide resin in the polyimide resin solution is preferably adjusted to a viscosity that is easy to handle in operation, relative to the total amount of the polyimide resin solution. 20% by mass or less, more preferably 10% by mass or less.

The manufacturing method of the present invention includes at least the following steps: while stirring the above-mentioned resin solution, at the same time adding at least one poor solvent to the resin solution to precipitate the polyimide-based resin.

Poor solvents for polyimide resins refer to solvents that are not easy to dissolve polyimide resins. For example, the solubility of polyimide resins at room temperature (20-30°C) is less than 1% by mass Solvent. The poor solvent may be one solvent or a mixture of two or more solvents. Examples of poor solvents include methanol, 2-propanol, ethyl acetate, tetrahydrofuran, toluene, hexane, and water.

Whether the solvent used is a good solvent or a poor solvent can be confirmed by the following method. Add polyimide resin to the solvent so that it becomes 1% by mass, and heat and/or stir as necessary to dissolve the resin in the solvent. If the solution is uniform at room temperature (20-30°C) If it is transparent, the solvent is judged to be a good solvent, and it is judged to be a poor solvent when there is an insoluble residue or the previously dissolved resin precipitates again. For example, in this embodiment, the solvent is measured and placed in a container and stirred, and the polyimide-based resin is added so as to become 1% by mass, and stirred at room temperature (24° C.) for 3 hours. As a result, if the solution is uniform and transparent, it is judged to be a good solvent, and if there is an insoluble residue, it is judged to be a poor solvent.

In the production method of the present invention, at least one poor solvent is added to the resin solution prepared by dissolving the polyimide resin in the good solvent to precipitate the polyimide resin. The added poor solvent may be one type or two or more types. In addition, the number of additions may be one time, or two or more times.

If a poor solvent is added to a resin solution prepared by dissolving a polyimide resin in a good solvent, the overall solubility of the solvent to the polyimide resin will decrease, thereby making the polyimide resin that cannot be completely dissolved The amine resin precipitates as a powder. Immediately after adding the poor solvent, a high concentration of the poor solvent appears locally, and then the poor solvent diffuses into the entire resin solution. If the concentration of the poor solvent is locally too high, the polyimide-based resin powder will be precipitated locally, and the polyimide-based resin powder will easily be mixed with impurities. In addition, it may be difficult to obtain powder because the solidified polyimide-based resin contains a solvent. In order to reduce the local concentration of the poor solvent, it is better to add the poor solvent while stirring the resin solution. However, when the stirring speed is too high, the fine unevenness of the polyimide resin powder may become excessive. , There are cases where the fluidity of polyimide resin powder is reduced. From the viewpoint of easily suppressing aggregation during the preparation of the varnish of the polyimide-based resin powder, it is preferable that the speed on the front end of the stirring blade is preferably 3.40 m/sec or less, more preferably 3.20 m/sec or less , It is more preferable to add a poor solvent to the resin solution while stirring under stirring conditions of 3.00 m/sec or less.

The production method of the present invention only needs to include at least adding at least one poor solvent to the resin solution prepared by dissolving the polyimide resin in the good solvent under the above-mentioned stirring conditions (the tip speed of the stirring blade) to make the polyimide resin The step of resin precipitation is sufficient. In the overall step of adding at least one poor solvent to the resin solution to precipitate the polyimide resin, the tip speed of the stirring blade can be set within the above-mentioned preferred range. In at least a part, the tip speed of the stirring blade is set within the above-mentioned preferable range. The length of time for setting the tip speed of the stirring blade within the above-mentioned preferable range can be appropriately adjusted according to the production scale of the polyimide resin powder, etc. Regarding the time when the tip speed of the stirring blade is set within the above-mentioned preferred range, from the viewpoint of easy production of polyimide-based resin powders that are not easy to agglomerate during the preparation of varnishes and have high solubility in varnishes, When the time required for the entire step of adding a poor solvent is set to 100%, it is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, and even more preferably 80% or more, especially Is more than 90%.

The front end speed of the stirring blade (V m/sec) is calculated from the rotation speed (X rpm) of the stirring blade and the diameter (D mm) of the stirring blade by the following formula. V[m/sec]=(X[rpm]/60)×(D[mm]/1000)×π

From the viewpoint of easily suppressing the increase in the local concentration of the poor solvent and the viewpoint of improving the solubility of the polyimide-based resin in the varnish, the lower limit of the tip speed is preferably 1.50 m/sec or more, more preferably 1.70 m/sec or more, more preferably 1.90 m/sec or more.

From the viewpoint of maintaining the solubility of the polyimide resin powder in the varnish and easily inhibiting aggregation during the preparation of the varnish, the rotation speed (X rpm) of the stirring blade is preferably 100 rpm or less, more preferably 90 rpm or less, more preferably 85 rpm or less, still more preferably 80 rpm or less, and particularly preferably 75 rpm or less. From the viewpoint of easily suppressing the increase in the local concentration of the poor solvent, the rotation speed of the stirring blade is preferably 30 rpm or more, more preferably 40 rpm or more, still more preferably 50 rpm or more, and particularly preferably 60 rpm or more.

The diameter (D mm) of the stirring blade is not particularly limited, and it is preferably adjusted within the range such that the front end speed and the rotation speed are within the above-mentioned preferable range. From this viewpoint, the diameter of the stirring blade is preferably 300 to 1,500 mm, more preferably 500 to 1,200 mm, and still more preferably 600 to 800 mm.

The method of adding the poor solvent is not particularly limited, but from the viewpoint of easily suppressing the increase in the local concentration of the poor solvent and easily controlling the addition rate, it is preferable to add it by a dropping method. In addition, from the viewpoint that it is easy to suppress the increase in the local concentration of the poor solvent and to increase the production efficiency of the polyimide resin powder, for example, it is possible to exemplify the use of multiple nozzles or nozzles with multiple branches. The method of adding by way, the method of adding using a shower nozzle, the dipping method of adding while the spray port of the alcohol solvent is immersed in the polyimide-based resin solution, the method of installing a dispersion plate at the tip of the nozzle Wait.

Regarding the addition of the poor solvent, one type of poor solvent may be added, or two or more solvents may be added. In addition, after adding the first poor solvent, it may be carried out by adding the second and third poor solvents according to the situation. In the production method of the present invention, for example, when the first poor solvent and the second poor solvent are added, the first poor solvent and the second poor solvent may each be one solvent or a mixture of two or more solvents. The first poor solvent and the second poor solvent may be different from each other, one may be one substance, the other may be a mixture of two or more substances, or both may be a mixture of two or more substances . Furthermore, the first poor solvent and the second poor solvent may be a mixture of two or more substances that are different from each other only in the mixing ratio. Moreover, a poor solvent whose composition changes continuously can also be used.

Regarding the addition of the poor solvent, from the viewpoint that it is easy to suppress the solvent contained in the precipitated polyimide-based resin powder, and the polyimide-based resin powder is easily produced efficiently, it is preferable to divide it twice Add two or more poor solvents above. When adding it in two or more times, it is preferable to add it in the order that the solubility to the polyimide-based resin becomes lower. For example, it is more preferable to add a solvent whose main component is an alcohol with 1 to 4 carbon atoms as the first poor solvent, and then add a solvent whose main component is water as the second poor solvent to precipitate the polyimide-based resin. When the polyimide resin is precipitated by this method, it is easy to slow down the change rate of solubility caused by the addition of a poor solvent, and it is easy to adjust the rate of solidification and precipitation of the polyimide resin. In addition, in this specification, the "solvent mainly composed of an alcohol with 1 to 4 carbon atoms" is also referred to as an "alcohol solvent", and the "solvent mainly composed of water" is also referred to as an "aqueous solvent" . In addition, in this specification, the "main component" means that it accounts for 70% by mass or more.

When the first poor solvent and the second poor solvent are added, the ratio of the alcohol having 1 to 4 carbons in the first poor solvent is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably More than 90% by mass. The ratio of water in the second poor solvent is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more.

Regarding the amount of poor solvent added, for example, the amount of polyimide resin in the polyimide resin solution is set to M (kg), the amount of good solvent is set to N (kg), in step ( 1) When the amount of the first poor solvent (preferably alcohol solvent) in contact with the polyimide resin solution is set to Z (kg), it is preferable that the mass ratio of each component satisfies the relational formula ( i) and (ii): 5≦N/M≦40 (i) 20≦Z/M≦100 (ii).

N/M in formula (i) represents the relationship between the amount of good solvent in the polyimide resin solution and the amount of polyimide resin. Furthermore, when a mixture of two or more solvents is used as a good solvent, the total mass is N. From the viewpoint of dissolving the polyimide resin in the polyimide resin solution and easily adjust it to a viscosity that is easy to handle, N/M is preferably 5 or more, more preferably 10 or more, and still more preferably 15 or more. From the viewpoint that the polyimide resin is easily precipitated in the step of adding the first poor solvent to precipitate the polyimide resin, N/M is preferably 40 or less, more preferably 35 or less, and still more preferably Below 30.

Z/M in formula (ii) represents the amount of polyimide resin in the polyimide resin solution and the amount of the polyimine resin solution and the first poor solvent added to the resin solution relationship. In addition, when two or more solvents are used as the first poor solvent, the total mass is set to Z. From the viewpoint of making the polyimide resin powder easy to precipitate, Z/M is preferably 23 or more, more preferably 25 or more, and still more preferably 30 or more. From the viewpoint of reducing waste, Z/M is preferably 90 or less, more preferably 85 or less, and still more preferably 80 or less.

It is preferable to add a second poor solvent (preferably an aqueous solvent) after adding the first poor solvent. By adding the second poor solvent after the first poor solvent is added, it is easy to suppress that the precipitated polyimide-based resin powder contains solvents such as a good solvent and the first poor solvent. As a result, it is easy to efficiently produce polyimide resin powder. Regarding the amount of the second poor solvent added, it is easy to reduce the amount of solvents such as the good solvent and the first poor solvent contained in the precipitated polyimide resin powder. The amount of polyimide resin in the resin solution is set to M (kg), the amount of good solvent is set to N (kg), and the first poor solvent (preferably alcohol) is added to the polyimide resin solution. When the amount of solvent) is set to Z ₁ (kg), and the amount of the second poor solvent (preferably an aqueous solvent) added is set to Z ₂ (kg), it is preferable that the mass ratio of each component satisfies the relationship Formulas (i), (iii) and (iv): 5≦N/M≦40 (i) 10≦Z ₁ /M≦50 (iii) 3≦Z ₂ /M≦30 (iv).

The N/M in formula (i) is related to the addition of the first poor solvent, as described above.

Z ₁ /M in formula (iii) represents the relationship between the amount of polyimide resin in the polyimide resin solution and the amount of the first poor solvent added to the polyimide resin solution. In addition, when a mixture of two or more solvents is used as the first poor solvent, the total mass is Z ₁ . From the standpoint that it is easy to suppress the rapid change in the solubility of the polyimide resin in the subsequent step of adding the second poor solvent, Z ₁ /M is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more . From the viewpoint of preventing excessive precipitation of the polyimide-based resin in the step of adding the first poor solvent, and the polyimide-based resin is easily precipitated as a powder when the second poor solvent is added, Z ₁ /M is preferable It is 50 or less, more preferably 40 or less, and still more preferably 35 or less.

Z ₂ /M in the formula (iv) represents the relationship between the amount of polyimide resin in the polyimide resin solution and the amount of the second poor solvent added. In addition, when a mixture of two or more solvents is used as the second poor solvent, the total mass is Z ₂ . From the viewpoint of easy precipitation of the polyimide-based resin as a powder, Z ₂ /M is preferably 3 or more, more preferably 5 or more, and still more preferably 8 or more. From the viewpoint of easily making the powder drying conditions milder or reducing the amount of waste liquid, Z ₂ /M is preferably 30 or less, more preferably 25 or less, and still more preferably 22 or less.

In addition to the above-mentioned step (1), the manufacturing method of the present invention may further include: (2) solid-liquid separation of the obtained mixture to obtain a polyimide resin combination containing the precipitated polyimide resin (A) step (hereinafter also referred to as "step (2)"); (3) the step of contacting the polyimide resin composition (a) with a poor solvent (hereinafter also referred to as "step (3) )”); and/or (4) drying step (hereinafter also referred to as “step (4)”).

Step (2) is a step of subjecting the obtained mixture to solid-liquid separation to obtain a polyimine resin composition (a) containing the precipitated polyimine resin. In step (2), if the mixture obtained in step (1) is subjected to solid-liquid separation, a polyimide resin containing the precipitated polyimide resin contained in the mixture and a part of the solvent contained in the mixture can be obtained. Amide resin composition. The polyimide resin composition is also called a wet cake composition, and is an intermediate for obtaining polyimine resin powder. In this specification, the polyimide-based resin composition obtained in step (2) is also referred to as "polyimine-based resin composition (a)".

The method of solid-liquid separation is not particularly limited. For example, the method is generally called filtration. Specifically, it can include: separation by gravity through a filter with different permeability of the precipitate and solvent; The method of separation; the method of separation by pressure difference. Examples of filters that can be used include centrifugal filters, druck filters, etc. The polyimide-based resin composition (a) thus obtained contains the precipitated polyimine-based resin powder, a good solvent, and the poor solvent contacted in step (1). Then, the step (4) of drying the polyimide-based resin composition (a) can be carried out to obtain polyimide-based resin powder, and the subsequent step (3) can also be used to make the polyimide After the resin composition (a) is in contact with the poor solvent, the step (4) of drying the obtained polyimide resin composition is further performed to obtain a polyimide resin powder. Among them, in the case of using the reaction solution in the production of polyimide resin from monomers as the polyimide resin solution to produce polyimide resin powder, it is easy to reduce the polyimide resin composition From the viewpoint of the amount of impurities contained in the substance, it is preferable to perform the contact step with the poor solvent in step (3). By reducing the amount of impurities contained in the polyimide-based resin composition, it is easy to reduce the amount of impurities in the polyimide-based resin powder obtained by drying the resin composition. As a result, it is easy to reduce the amount of impurities in the polyimide-based resin powder. Adjust the angle of repose and ratio (A ² /B) of the imine-based resin powder to the required range, and it is easy to produce a polyimide-based resin powder that is not easy to agglomerate during the preparation of varnish and has high solubility in the varnish .

Step (3) is a step of contacting the polyimide resin composition (a) with at least one poor solvent. Through step (3), the precipitated polyimide resin powder can be washed. In step (3), one type of poor solvent may be used, or two or more types of poor solvent may be used. In addition, the number of times of contact with the poor solvent may be one time, or two or more times. In addition, contact and solid-liquid separation may be continuously performed. Specifically, regarding step (3), you can add a poor solvent to the polyimide-based resin composition (a) while filtering at the same time, or you can add it to the polyimide-based resin composition (a) After mixing the poor solvent, the mixture is subjected to solid-liquid separation. As the poor solvent used in step (3), the solvent described as the poor solvent added in step (1) is similarly applicable. From the viewpoint of ease of reducing the amount of impurities contained in the polyimide-based resin composition, it is preferable to use an alcohol-based solvent in step (3). The contact method with the poor solvent is not particularly limited. For example, a poor solvent may be added to the polyimide resin composition (a), or the polyimide resin composition (a) may be mixed with the poor solvent. After the contact, by a method generally called filtration, specifically, through a filter with different permeability between the precipitate and the solvent, the method of separation by gravity, the method of separation by centrifugal force, and the method of separation by pressure In the method of separation, the obtained mixture is subjected to solid-liquid separation to obtain a polyimide resin composition. The polyimide-based resin composition obtained in step (3) is also referred to as "polyimine-based resin composition (a')".

Step (4) is a step of drying the polyimide resin composition (a) obtained in step (2) or the polyimide resin composition (a') obtained in step (3). The polyimide-based resin composition (a) or (a') is dried to remove the solvent in the composition to obtain a polyimide-based resin powder. The polyimide resin composition is also called a wet cake composition, and is an intermediate for obtaining polyimide resin powder. The drying conditions are not particularly limited as long as the solvent in the polyimide resin composition (a) or (a') can be removed. For example, it may be heating at a temperature of about 50 to 250°C under reduced pressure or atmospheric pressure. Conditions such as 1 to 48 hours.

＜Polyimide resin＞ The polyimide resin of the present invention may be at least one resin selected from the group consisting of polyimide resin, polyimide resin, and polyimide resin. The polyimide resin may be one type of polyimine resin, or two or more types of polyimide resin. From the viewpoint of film forming properties, the polyimide-based resin is preferably a polyimide resin. The polyimide resin is preferably an aromatic polyimide resin. The so-called polyimide resin is aromatic, which means that the structural unit constituting the polyimide resin is preferably 60 mol% or more, more preferably 80 mol% or more, and more preferably 85 mol% The above are structural units containing aromatic structures.

In a preferred embodiment of the present invention, the polyimide resin is preferably a polyimide resin having a structural unit represented by formula (1), or a structural unit represented by formula (1) and formula (2) Polyimide resin of the structural unit represented. The formula (1) and formula (2) are described below. The description of formula (1) is about both polyimide resin and polyimide resin, and the description of formula (2) is about polyimide resin. Amine imine resin. [化1]

The structural unit represented by formula (1) is a structural unit formed by the reaction of a tetracarboxylic acid compound and a diamine compound, and the structural unit represented by formula (2) is a structural unit formed by the reaction of a dicarboxylic acid compound and a diamine compound. In a preferred aspect of the present invention in which the polyimide resin is an aromatic polyimide resin, it is preferable to constitute the structural unit represented by formula (1) and the structure represented by formula (2) At least one of the tetracarboxylic acid compound, diamine compound, and dicarboxylic acid compound of the structural unit is an aromatic compound (aromatic tetracarboxylic acid compound, aromatic diamine compound, and/or aromatic dicarboxylic acid compound).

In formula (2), Z is a divalent organic group, preferably a hydrocarbon group with 1 to 8 carbons, a hydrocarbon group with 1 to 8 carbons substituted by fluorine, an alkoxy group with 1 to 6 carbons, or Fluorine-substituted alkoxy-substituted divalent organic groups of 4-40 carbons, more preferably hydrocarbon groups of 1-8 carbons, hydrocarbon groups of 1-8 carbons substituted by fluorine, A C1-C6 alkoxy group or a fluorine-substituted C1-C6 alkoxy group substituted with a cyclic structure of a C4-C40 divalent organic group. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. Examples of the organic group of Z include: formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), Among the bonding bonds of the groups represented by formula (28) and formula (29), two non-adjacent groups are substituted with hydrogen atoms, and a bivalent chain hydrocarbon group with 6 or less carbon atoms, as the heterocyclic structure of Z, A group having a thiophene ring skeleton can be exemplified. From the viewpoint of easily lowering the YI value, which is an index indicating the yellowness of an optical film, the group represented by formula (20) to formula (27) and a group having a thiophene ring skeleton are preferable.

[式(20')～式(29')中，W¹ 及＊如式(20)～式(29)中之定義] 所表示之2價有機基。再者，式(20)～式(29)及式(20')～式(29')中之環上之氫原子可經碳數1～8之烴基、經氟取代之碳數1～8之烴基、碳數1～6之烷氧基、經氟取代之碳數1～6之烷氧基取代。 樹脂於式(b)中之Z含有上述式(20')～式(29')之任一者所表示之結構單元之情形時，該樹脂含有該結構單元、並且進而含有下式(d1)：

[式(d1)中，R²⁴ 相互獨立地表示氫原子、鹵素原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R²⁵ 表示R²⁴ 或-C(=O)-＊，＊表示鍵結鍵] 所表示之源自羧酸之結構單元就容易提高清漆之成膜性、容易使所獲得之光學膜具有均勻性之觀點而言較佳。 於R²⁴ 中，作為碳數1～6之烷基、碳數1～6之烷氧基及碳數6～12之芳基，分別可列舉關於後述式(3)中之R¹ ～R⁸ 所例示者。作為結構單元(d1)，具體而言，可列舉：R²⁴ 及R²⁵ 均為氫原子之結構單元(源自二羧酸化合物之結構單元)，R²⁴ 均為氫原子、R²⁵ 表示-C(=O)-＊之結構單元(源自三羧酸化合物之結構單元)等。 於本發明之一實施形態中，聚醯胺醯亞胺樹脂可包含複數種Z，複數種Z相互可相同，亦可不同。尤其就容易提昇由聚醯亞胺系樹脂粉體獲得之膜之表面硬度及光學特性之觀點而言、以及容易防止清漆製備時之凝集之觀點而言，較佳為Z之至少一部分係以式(3a)：

[式(3a)中，R^g 及R^h 相互獨立地表示鹵素原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R^g 及R^h 所含之氫原子可相互獨立地被取代為鹵素原子，A、m及＊係與式(3)中之A、m及＊相同，t及u相互獨立地為0～4之整數] 表示，更佳為係以式(3) [化2]

[式(3)中，R¹ ～R⁸ 相互獨立地表示氫原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R¹ ～R⁸ 所含之氫原子可相互獨立地被取代為鹵素原子， A相互獨立地表示單鍵、-O-、-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -、-SO₂ -、-S-、-CO-或-N(R⁹ )-，R⁹ 表示氫原子、可經鹵素原子取代之碳數1～12之1價烴基， m為0～4之整數， ＊表示鍵結鍵] 表示。As the organic group of Z, it is more preferably formula (20'), formula (21'), formula (22'), formula (23'), formula (24'), formula (25'), formula (26') , Formula (27'), formula (28') and formula (29'):

[In formula (20') to formula (29'), W ¹ and * are as defined in formula (20) to formula (29)] A divalent organic group represented. Furthermore, the hydrogen atoms in the ring in formulas (20) to (29) and (20') to (29') can be substituted by hydrocarbon groups with 1 to 8 carbons, and carbons 1 to 8 substituted by fluorine The hydrocarbyl group, the alkoxy group having 1 to 6 carbon atoms, and the alkoxy group having 1 to 6 carbon atoms substituted by fluorine. When the Z of the resin in formula (b) contains the structural unit represented by any of the above formulas (20') to (29'), the resin contains the structural unit and further contains the following formula (d1) :

[In formula (d1), R ²⁴ independently represents a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons or an aryl group with 6 to 12 carbons, and R ²⁵ represents R ²⁴ or -C(=O)-*, ＊represents the bonding bond] The structural unit derived from the carboxylic acid represented by it is easy to improve the film-forming property of the varnish, and it is easy to make the obtained optical film have uniformity. The words are better. In R ²⁴ , examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons include R ¹ to R ⁸ in the formula (3) described below, respectively. Exemplified. As the structural unit (d1), specifically, a structural unit in which R ²⁴ and R ²⁵ are both hydrogen atoms (a structural unit derived from a dicarboxylic acid compound), R ²⁴ is a hydrogen atom, and R ²⁵ represents -C (=O)-*The structural unit (the structural unit derived from the tricarboxylic acid compound), etc. In one embodiment of the present invention, the polyimide resin may include a plurality of types of Z, and the plurality of types of Z may be the same or different from each other. In particular, from the viewpoint of easy improvement of the surface hardness and optical properties of the film obtained from the polyimide resin powder, and the viewpoint of easy prevention of aggregation during the preparation of the varnish, it is preferable that at least a part of Z is represented by the formula (3a):

[In formula (3a), R ^g and R ^h independently represent a halogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons, R ^g and The hydrogen atoms contained in R ^h can be substituted with halogen atoms independently of each other. A, m and * are the same as A, m and * in formula (3), and t and u are independently integers from 0 to 4] It is better to use formula (3) [化2]

[In formula (3), R ¹ to R ⁸ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons, R ¹ to The hydrogen atoms contained in R ⁸ can be independently substituted with halogen atoms, and A independently represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, R ⁹ represents a hydrogen atom, which can be substituted by a halogen atom The monovalent hydrocarbon group with 1-12 carbon atoms, m is an integer of 0-4, and * represents a bonding bond].

In formula (3) and formula (3a), A represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, from the viewpoint of the buckling resistance of the film obtained by using polyimide resin powder In particular, it preferably represents -O- or -S-, and more preferably represents -O-. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or carbon The number of aryl groups from 6 to 12. R ^g and R ^h independently represent a halogen atom, an alkyl group having 1 to 6 carbons, an alkoxy group having 1 to 6 carbons, or an aryl group having 6 to 12 carbons. Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, tertiary butyl, n-pentyl, and 2-methyl Butyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, etc. Examples of alkoxy groups having 1 to 6 carbon atoms include: methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tertiary butoxy, and pentoxy , Hexyloxy, cyclohexyloxy, etc. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, naphthyl, biphenyl and the like. From the viewpoint of the surface hardness and flexibility of the film obtained by using the polyimide resin powder, R ¹ to R ⁸ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more It preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably represents a hydrogen atom. Here, the hydrogen atoms contained in R ¹ to R ⁸ , R ^g and R ^h may be substituted with halogen atoms independently of each other. R ⁹ represents a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of monovalent hydrocarbon groups having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, tertiary butyl, n-pentyl, 2-methyl Butyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, tertiary octyl, n-nonyl, n-decyl, etc., which can be substituted by halogen atoms . As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned. The polyimide resin may contain a plurality of types of A, and the plurality of types of A may be the same or different from each other.

In the formula (3a), t and u are independently an integer of 0-4, preferably an integer of 0-2, more preferably 0 or 1, and even more preferably 0. In formula (3) and formula (3a), m is an integer in the range of 0-4. If m is in this range, it is easy to make the film obtained by using polyimide resin powder have flex resistance or elasticity The modulus becomes good. Moreover, in formula (3) and formula (3a), m is preferably an integer in the range of 0-3, more preferably 0-2, still more preferably 0 or 1, and particularly preferably 0. If m is in this range, it is easy to improve the buckling resistance or elastic modulus of the film. In addition, Z may include one or two or more structural units represented by formula (3) or formula (3a). From the viewpoint of improving the elastic modulus and buckling resistance of the optical film, and reducing the YI value, it may Contains two or more structural units with different values of m, preferably two structural units with different values of m. In this case, from the viewpoint of easily realizing the higher elastic modulus, buckling resistance and lower YI value of the film obtained by using polyimide resin powder, it is preferable that the resin is in Z Contains a structural unit derived from terephthalic acid or isophthalic acid as a structural unit represented by formula (3) or formula (3a) where m is 0, more preferably contains the structural unit and further contains a formula where m is 1 (3) or a structural unit represented by formula (3a).

所表示之結構單元作為式(3)所表示之結構單元。於該情形時，容易提昇使用聚醯亞胺系樹脂粉體所獲得之膜之表面硬度及耐屈曲性，容易降低YI值。In a preferred embodiment of the present invention, the resin has a structural unit in which m=0 and R ⁵ to R ⁸ are hydrogen atoms as the structural unit represented by formula (3). In a more preferred embodiment of the present invention, the resin has a structural unit in which m=0 and R ⁵ to R ⁸ are hydrogen atoms, and the formula (3'): [化 3]

The structural unit represented is the structural unit represented by formula (3). In this case, it is easy to increase the surface hardness and buckling resistance of the film obtained by using the polyimide-based resin powder, and it is easy to reduce the YI value.

In a preferred embodiment of the present invention, when the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) of the polyamide imide resin is set to 100 mol%, the formula The ratio of the structural unit represented by (3) or formula (3a) is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, and even more preferably 50 mol% % Or more, particularly preferably 60 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, and still more preferably 80 mol% or less. If the ratio of the structural unit represented by the formula (3) or formula (3a) is more than the above lower limit, it is easy to increase the surface hardness of the film obtained by using the polyimide-based resin powder, and it is easy to increase the buckling resistance or elasticity Modulus. If the ratio of the structural units represented by the formula (3) or formula (3a) is less than the above upper limit, it is easy to suppress the resin-containing content caused by the hydrogen bond between the amide bonds derived from the formula (3) or formula (3a) The viscosity of the varnish increases, which easily improves the processability of the film. Moreover, it is also preferable to contain the structural unit represented by formula (2) which has Z represented by formula (3) where m is 0, and further contain the structural unit represented by said formula (d1).

In addition, when the polyamide imide resin has a structural unit of formula (3) or formula (3a) with m=1 to 4, the structure represented by formula (1) of the polyamide imide resin When the total of the unit and the structural unit represented by formula (2) is set to 100 mol%, the ratio of the structural unit of formula (3) or formula (3a) where m is 1 to 4 is preferably 2 mol% or more, More preferably 4 mol% or more, further preferably 6 mol% or more, particularly preferably 8 mol% or more, and preferably 70 mol% or less, more preferably 50 mol% or less, and still more preferred It is 30 mol% or less, more preferably 15 mol% or less, and particularly preferably 12 mol% or less. If the ratio of the structural units of formula (3) or formula (3a) in which m is 1 to 4 is more than the above lower limit, it is easy to increase the surface hardness and buckling resistance of the film obtained using the polyimide resin powder. If the ratio of the structural units of formula (3) or formula (3a) where m is 1 to 4 is below the above upper limit, it is easy to suppress the hydrogen bond originating from the amide bond of formula (3) or formula (3a) The viscosity of the resin-containing varnish increases, which easily improves the processability of the film. Furthermore, the content of the structural unit represented by formula (1), formula (2), formula (3), or formula (3a) can be measured using, for example, ¹ H-NMR, or can also be calculated based on the addition ratio of raw materials.

In a preferred embodiment of the present invention, the Z in the polyimide resin is preferably 30 mol% or more, more preferably 40 mol% or more, and still more preferably 45 mol% or more , More preferably 50 mol% or more, and particularly preferably 70 mol% or more, is a structural unit represented by formula (3) or formula (3a) or formula (3a) in which m is 0-4. If the above lower limit of Z is a structural unit represented by formula (3) where m is 0 to 4, it is easy to increase the surface hardness of the film obtained by using polyimide resin powder, and it is also easy to improve the buckling resistance And elastic modulus. Moreover, as long as 100 mol% or less of Z in the polyimide resin is a structural unit represented by formula (3) where m is 0-4. In addition, the ratio of structural units represented by formula (3) or formula (3a) in which m in the resin is 0 to 4 can be measured using, for example, ¹ H-NMR, or can be calculated based on the addition ratio of raw materials.

In a preferred embodiment of the present invention, the Z in the polyimide resin is preferably 5 mol% or more, more preferably 8 mol% or more, and still more preferably 10 mol% or more , Particularly preferably, 12 mol% or more is expressed by formula (3) or formula (3a) where m is 1 to 4. If the above lower limit of Z of the polyimide resin is expressed by the formula (3) or formula (3a) where m is 1 to 4, it is easy to improve the film obtained by using the polyimide resin powder Surface hardness, and easy to improve buckling resistance and elastic modulus. In addition, Z is preferably 90 mol% or less, more preferably 70 mol% or less, more preferably 50 mol% or less, and particularly preferably 30 mol% or less, and m is 1 to 4 The formula (3) or formula (3a) is expressed. If the upper limit of Z or lower is represented by formula (3) where m is 1 to 4, it is easy to suppress the hydrogen bond originating from formula (3) or formula (3a) where m is 1 to 4 between the amide bonds The viscosity of the resin-containing varnish increases, which easily improves the processability of the film. In addition, the ratio of structural units represented by formula (3) or formula (3a) in which m in the resin is 1 to 4 can be measured using, for example, ¹ H-NMR, or can be calculated based on the addition ratio of raw materials.

In formula (1) and formula (2), X independently represents a divalent organic group, preferably a divalent organic group having 4 to 40 carbons, more preferably a carbon number of 4 to 40 having a cyclic structure The divalent organic base. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. Regarding the aforementioned organic group, the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. In one embodiment of the present invention, the polyimide resin or polyimide resin may include multiple types of X, and the multiple types of X may be the same or different from each other. Examples of X include: formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17), and formula (18) The group represented; the hydrogen atom in the group represented by the formula (10) ~ formula (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and a chain with a carbon number of 6 or less式hydrocarbyl.

[化1]

In formulas (10) to (18), * represents a bonding bond, and V ¹ , V ² and V ³ independently represent a single bond, -O-, -S-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -CO- or -N(Q)-. Here, Q represents a monovalent hydrocarbon group having 1 to 12 carbons which may be substituted with a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include the groups described for R ⁹ above. An example is as follows: V ¹ and V ³ are single bonds, -O- or -S-, and V ² is -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -or -SO ₂ -. The bonding positions of V ¹ and V ² with respect to each ring, and the bonding positions of V ² and V ³ with respect to each ring are independent of each other. Preferably, they are meta or para with respect to each ring, and more preferably are para. .

Among the bases represented by formulas (10) to (18), from the viewpoint of easily improving the surface hardness and buckling resistance of a film obtained by using polyimide resin powder, formula (13) is preferred , Formula (14), Formula (15), Formula (16), and Formula (17) are more preferably groups represented by Formula (14), Formula (15), and Formula (16). In addition, V ¹ , V ² and V ³ are independently preferably single bonds, -O- or from the viewpoint of easily improving the surface hardness and flexibility of the film obtained by using the polyimide resin powder. -S-, more preferably a single bond or -O-.

[式(4)中，R¹⁰ ～R¹⁷ 相互獨立地表示氫原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R¹⁰ ～R¹⁷ 所含之氫原子可相互獨立地被取代為鹵素原子，＊表示鍵結鍵] 所表示之結構單元。若式(1)及式(2)中之複數個X之至少一部分係式(4)所表示之基，則容易提高使用聚醯亞胺系樹脂粉體所獲得之膜之表面硬度及透明性。In a preferred embodiment of the present invention, at least a part of the plurality of X in formula (1) and formula (2) is formula (4): [化5]

[In formula (4), R ¹⁰ to R ¹⁷ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons, R ¹⁰ to The hydrogen atoms contained in R ¹⁷ can be substituted with halogen atoms independently of each other, and * represents the structural unit represented by the bonding bond]. If at least a part of the plural X in formula (1) and formula (2) is the base represented by formula (4), it is easy to improve the surface hardness and transparency of the film obtained by using polyimide resin powder .

In the formula (4), R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, and a carbon number of 1 to 6 The alkoxy group or the aryl group with 6-12 carbons. Examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, or aryl groups having 6 to 12 carbons include the alkyl groups having 1 to 6 carbons in formula (3), and carbon number 1. Exemplified by ∼6 alkoxy or carbon 6-12 aryl groups. R ¹⁰ to R ¹⁷ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Here, R ¹⁰ to R ¹⁷ include The hydrogen atoms can be substituted with halogen atoms independently of each other. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. From the viewpoints of the surface hardness, transparency, and flex resistance of the optical film, it is more preferred that R ¹⁰ to R ¹⁷ independently represent a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group, and more Preferably, R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ represent a hydrogen atom, R ¹¹ and R ¹⁷ represent a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and R is particularly preferred. ¹¹ and R ¹⁷ represent methyl or trifluoromethyl.

所表示之結構單元，即，複數個X之至少一部分係式(4')所表示之結構單元。於該情形時，藉由含有氟元素之骨架來提高聚醯亞胺系樹脂粉體於溶劑中之溶解性。又，容易降低清漆之黏度，容易提昇光學膜之加工性。又，藉由含有氟元素之骨架，容易提昇使用聚醯亞胺系樹脂粉體所獲得之膜之光學特性。In a preferred embodiment of the present invention, the structural unit represented by formula (4) is formula (4'): [化6]

The structural unit represented, that is, at least a part of the plurality of Xs is the structural unit represented by formula (4'). In this case, the solubility of the polyimide resin powder in the solvent is improved by the skeleton containing the fluorine element. In addition, it is easy to reduce the viscosity of the varnish, and it is easy to improve the processability of the optical film. In addition, the fluorine-containing skeleton makes it easy to improve the optical properties of the film obtained using the polyimide-based resin powder.

In a preferred embodiment of the present invention, X in the polyimide resin is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more. It is represented by formula (4), especially formula (4'). If X in the above-mentioned range in the polyimide resin is represented by formula (4), especially formula (4'), it is easy to improve the polyimide resin powder by the skeleton containing the fluorine element Solubility in solvents. In addition, it is easy to reduce the viscosity of the varnish, and it is easy to improve the processability of the film obtained by using the polyimide resin powder. Furthermore, with the fluorine element-containing skeleton, it is easy to improve the optical properties of the film obtained by using the polyimide resin powder. Furthermore, it is preferable that 100 mol% or less of X in the polyimide resin is represented by formula (4), especially formula (4'). X in the polyimide resin can be formula (4), especially formula (4'). The ratio of the structural unit represented by the formula (4) of X in the above resin can be measured using, for example, ¹ H-NMR, or can also be calculated based on the addition ratio of the raw materials.

In the formula (1), Y represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms, and more preferably a tetravalent organic group having 4 to 40 carbon atoms having a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic, and heterocyclic structures. The above-mentioned organic group is an organic group in which the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In this case, the carbon number of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1-8. In one embodiment of the present invention, the polyimide-based resin may include multiple types of Y, and the multiple types of Y may be the same or different from each other. As Y, the following formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( 28) and the group represented by the formula (29); the hydrogen atom in the group represented by the formula (20) ~ formula (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; And tetravalent chain hydrocarbon group with carbon number 6 or less.

[化7]

In formulas (20) to (29), * represents a bonding bond, W ¹ represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom can be substituted with a fluorine atom, and a specific example includes a phenylene group.

Among the groups represented by formulas (20) to (29), from the viewpoint of the surface hardness and buckling resistance of a film obtained by using polyimide resin powder, formulas (26) and The group represented by formula (28) or formula (29) is more preferably a group represented by formula (26). In addition, W ¹ is preferably a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ independently of each other, from the viewpoints that it is easy to increase the surface hardness and buckling resistance of the optical film, and to decrease the YI value. -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably a single bond, -O-, -CH ₂ -, -CH(CH ₃ )- , -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -, more preferably a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) ₂ -.

[式(5)中，R¹⁸ ～R²⁵ 相互獨立地表示氫原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R¹⁸ ～R²⁵ 所含之氫原子可相互獨立地被取代為鹵素原子，＊表示鍵結鍵] 及/或式(9)

[式(9)中，R³⁵ ～R⁴⁰ 相互獨立地表示氫原子、碳數1～6之烷基或碳數6～12之芳基，R³⁵ ～R⁴⁰ 所含之氫原子可相互獨立地被取代為鹵素原子，＊表示鍵結鍵] 表示。若複數個式(1)中之Y之至少一部分係以式(5)及/或式(9)表示，則容易提昇光學膜之耐摩擦性、彈性模數及光學特性。In a preferred embodiment of the present invention, Y in the polyimide resin is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more. Formula (26) represents. If Y in the above-mentioned range in the polyimide-based resin is in the formula (26), preferably W ¹ is a single bond, -C(CH ₃ ) ₂ -or -C(CF ₃ ) _2- 26). More preferably, W ¹ is a single bond or -C(CF ₃ ) ₂ -expressed by the formula (26), it is easy to improve the friction resistance, elastic modulus and flex resistance of the optical film, and it is easy to reduce the optical film The YI value. The ratio in which Y in the polyimide-based resin is a structural unit represented by formula (26) can be measured using, for example, ¹ H-NMR, or can also be calculated based on the addition ratio of raw materials. In a preferred embodiment of the present invention, at least a part of the plural Y in formula (1) is represented by formula (5): [化8]

[In formula (5), R ¹⁸ to R ²⁵ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons, and R ¹⁸ to The hydrogen atoms contained in R ²⁵ can be substituted with halogen atoms independently of each other, * represents a bonding bond] and/or formula (9)

[In formula (9), R ³⁵ to R ⁴⁰ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons or an aryl group having 6 to 12 carbons, and the hydrogen atoms contained in R ³⁵ to R ⁴⁰ may be independent of each other Ground is substituted with a halogen atom, * represents a bonding bond]. If at least a part of Y in a plurality of formulas (1) is represented by formulas (5) and/or formulas (9), it is easy to improve the friction resistance, elastic modulus, and optical properties of the optical film.

In the formula (5), R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbons, and a carbon number of 1 to 6 The alkoxy group or the aryl group with 6-12 carbons. Examples of alkyl groups having 1 to 6 carbons, alkoxy groups having 1 to 6 carbons, and aryl groups having 6 to 12 carbons include the above-mentioned alkyl groups having 1 to 6 carbons and carbon numbers in the formula (3). The alkoxy group of 1 to 6 or the aryl group of 6 to 12 carbons are exemplified. R ¹⁸ to R ²⁵ independently of each other preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Here, R ¹⁸ to R ²⁵ include The hydrogen atoms can be substituted with halogen atoms independently of each other. As this halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. From the viewpoint of easy improvement of the surface hardness, flex resistance, and transparency of the optical film, R ¹⁸ to R ²⁵ are independent of each other and are preferably a hydrogen atom, a methyl group, a fluorine group, a chlorine group, or a trifluoromethyl group. More preferably, R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ and R ²⁵ are hydrogen atoms, R ²¹ and R ²² are hydrogen atoms, methyl, fluoro, chloro, or trifluoromethyl, and most preferably R ²¹ and R ²² are methyl or trifluoromethyl.

即，複數個Y之至少一部分為式(5')及/或式(9')所表示之結構單元。於該情形時，藉由含有氟元素之骨架而容易提高聚醯亞胺系樹脂粉體於溶劑中之溶解性。又，容易降低清漆之黏度，容易提昇膜之加工性。又，藉由含有氟元素之骨架，容易提昇使用聚醯亞胺系樹脂粉體所獲得之膜之光學特性。In a preferred embodiment of the present invention, the structural unit represented by formula (5) is the base represented by formula (5'), and the structural unit represented by formula (9) is the base represented by formula (9') . [化9]

That is, at least a part of a plurality of Y is a structural unit represented by formula (5') and/or formula (9'). In this case, it is easy to improve the solubility of the polyimide resin powder in the solvent by the skeleton containing the fluorine element. In addition, it is easy to reduce the viscosity of the varnish, and it is easy to improve the processability of the film. In addition, the fluorine-containing skeleton makes it easy to improve the optical properties of the film obtained using the polyimide-based resin powder.

In a preferred embodiment of the present invention, Y in the polyimide resin is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more. Formula (5), especially formula (5') is represented. If Y in the above-mentioned range in the polyimide resin is represented by formula (5), especially formula (5'), it is easy to improve the polyimide resin powder by the skeleton containing the fluorine element Solubility in solvents. In addition, it is easy to reduce the viscosity of the varnish, and it is easy to improve the processability of the film. Furthermore, with the fluorine-containing skeleton, it is easy to improve the optical properties of the film obtained by using the polyimide-based resin powder. Furthermore, it is preferable that 100 mol% or less of Y in the polyimide resin is represented by formula (5), especially formula (5'). Y in the polyimide resin may be formula (5), especially formula (5'). The ratio of the structural unit represented by the formula (5) of Y in the polyimide-based resin can be measured using, for example, ¹ H-NMR, or can be calculated based on the addition ratio of the raw materials.

The polyimide resin may include the structural unit represented by the formula (30) and/or the structural unit represented by the formula (31), and may also include the structural unit represented by the formula (1) and formula (2) The structural unit represented by formula (30) and/or the structural unit represented by formula (31). [化10]

In formula (30), Y ¹ is a tetravalent organic group, preferably an organic group in which the hydrogen atom in the organic group can be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples of Y ^{1 include} : formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) ) And the group represented by the formula (29); the hydrogen atom in the group represented by the formula (20) ~ formula (29) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and A tetravalent chain hydrocarbon group with 6 or less carbon atoms. In one embodiment of the present invention, the polyimide-based resin may include a plurality of Y ¹ , and the plurality of Y ¹ may be the same or different from each other.

In formula (31), Y ² is a trivalent organic group, preferably an organic group in which the hydrogen atom in the organic group can be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ² , the above-mentioned formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula ( 28) A group in which any one of the bonding bonds of the group represented by the formula (29) is substituted with a hydrogen atom; and a trivalent chain hydrocarbon group with 6 or less carbon atoms. In one embodiment of the present invention, the polyimide-based resin may include multiple types of Y ² , and the multiple types of Y ² may be the same or different from each other.

In formula (30) and formula (31), X ¹ and X ² are independently a divalent organic group, preferably an organic group in which a hydrogen atom in the organic group can be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples of X ¹ and X ² include the above-mentioned formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), and formula (17) And the group represented by the formula (18); the hydrogen atom in the group represented by the formula (10) to the formula (18) is substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; and carbon Chain hydrocarbon group with number 6 or less.

In one embodiment of the present invention, the polyimide-based resin includes structural units represented by formula (1) and/or formula (2), and optionally represented by formula (30) and/or formula (31) The structural unit. In addition, from the viewpoints of the optical properties, surface hardness, and buckling resistance of the film obtained by using the polyimide resin powder, in the above polyimide resin, the formulas (1) and (2) The structural unit represented is based on all structural units represented by formula (1) and formula (2), and optionally formula (30) and formula (31), preferably 80 mol% or more, more preferably 90 mol% Ear% or more, more preferably 95 mol% or more. Furthermore, in the polyimide resin, the structural units represented by formula (1) and formula (2) are based on formula (1) and formula (2), as well as formula (30) and/or formula ( 31) All the structural units indicated are usually 100% or less. In addition, the said ratio can be measured using, for example, ¹ H-NMR, or it can also be calculated based on the addition ratio of raw materials.

In one embodiment of the present invention, the content of the polyimide resin in the film obtained by using the polyimide resin powder relative to 100 parts by mass of the film, preferably 10 parts by mass or more, more preferably It is 30 parts by mass or more, more preferably 50 parts by mass or more, and preferably 99.5 parts by mass or less, more preferably 95 parts by mass or less. If the content of the polyimide resin is within the above range, it is easy to improve the optical properties and elastic modulus of the film obtained by using the polyimide resin powder.

In the polyamide imide resin, the content of the structural unit represented by formula (2) is 1 mol of the structural unit represented by formula (1), preferably 0.1 mol or more, more preferably 0.5 mol Above, it is more preferably 1.0 mol or more, more preferably 1.5 mol or more, and preferably 6.0 mol or less, more preferably 5.0 mol or less, and still more preferably 4.5 mol or less. If the content of the structural unit represented by the formula (2) is more than the above lower limit, it is easy to increase the surface hardness of the film obtained using the polyimide-based resin powder. Moreover, if the content of the structural unit represented by the formula (2) is below the above upper limit, the viscosity increase caused by the hydrogen bond between the amide bonds in the formula (2) is suppressed, and the processability of the optical film is easily improved.

In a preferred embodiment of the present invention, the polyimide-based resin may contain halogen atoms such as fluorine atoms that can be introduced via the above-mentioned fluorine-containing substituents. When the polyimide-based resin contains halogen atoms, it is easy to increase the elastic modulus of the film containing the polyimide-based resin, and it is easy to reduce the YI value. If the elastic modulus of the film is high, when the film is used in, for example, a flexible display device, it is easy to suppress damage and wrinkles of the film. Moreover, if the YI value of the film is low, the transparency and visibility of the film are easily improved. The halogen atom is preferably a fluorine atom. As a preferable fluorine-containing substituent for making a polyimide resin contain a fluorine atom, a fluorine group and a trifluoromethyl group are mentioned, for example.

Regarding the content of halogen atoms in the polyimide resin, based on the mass of the polyimide resin, it is preferably 1-40% by mass, more preferably 5-40% by mass, and still more preferably 5 ～30% by mass. If the content of halogen atoms is more than the above lower limit, it is easy to further increase the elastic modulus of the film containing the polyimide-based resin, it is easy to reduce the water absorption, it is easy to further reduce the YI value, and it is easy to further improve the transparency and visibility. If the content of halogen atoms is less than the above upper limit, it is easy to synthesize resin.

The imidization rate of the polyimide resin is preferably 90% or more, more preferably 93% or more, and still more preferably 96% or more. From the viewpoint of easy improvement of the optical homogeneity of the film containing the polyimide-based resin, the imidization rate is preferably at least the above lower limit. In addition, the upper limit of the imidization rate is 100% or less. The imidization rate represents the value of the molar amount of the amide bond in the polyimine resin relative to the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyimine resin. The ratio. Furthermore, when the polyimide resin contains a tricarboxylic acid compound, it means that the molar amount of the amide bond in the polyimide resin and the polyimide resin is relative to the polyimide resin. The ratio of the value of twice the molar amount of the structural unit derived from the tetracarboxylic acid compound to the total molar amount of the structural unit derived from the tricarboxylic acid compound in the resin. In addition, the imidization rate can be determined by IR method, NMR method, etc., for example, the NMR method can be measured by the method described in the examples.

A commercially available product can also be used for the polyimide resin. Examples of commercially available products of polyimide resins include NEOPRIM (registered trademark) manufactured by Mitsubishi Gas Chemical Co., Ltd., KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd., and the like.

[式(3'')中，R¹ ～R⁸ 相互獨立地表示氫原子、碳數1～6之烷基、碳數1～6之烷氧基或碳數6～12之芳基，R¹ ～R⁸ 所含之氫原子可相互獨立地被取代為鹵素原子， A表示單鍵、-O-、-CH₂ -、-CH₂ -CH₂ -、-CH(CH₃ )-、-C(CH₃ )₂ -、-C(CF₃ )₂ -、-SO₂ -、-S-、-CO-或-N(R⁹ )-， R⁹ 表示氫原子、可經鹵素原子取代之碳數1～12之1價烴基， m為0～4之整數， R³¹ 及R³² 相互獨立地表示羥基、甲氧基、乙氧基、正丙氧基、異丙氧基、正丁氧基、第二丁氧基、第三丁氧基或氯原子]<Method for producing polyimide resin> Polyimide resin can be produced by using, for example, tetracarboxylic acid compounds and diamine compounds as main raw materials, and polyimide resin can be produced by, for example, tetracarboxylic acid compounds and diamine compounds. Acid compounds and diamine compounds are produced as main raw materials. Here, the dicarboxylic acid compound preferably contains at least the compound represented by formula (3''). [化11]

[In formula (3''), R ¹ to R ⁸ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbons, an alkoxy group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons, R The hydrogen atoms contained in ¹ to R ⁸ can be independently substituted with halogen atoms. A represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-,- C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ⁹ )-, R ⁹ represents a hydrogen atom, which can be substituted by a halogen atom A monovalent hydrocarbon group with 1-12 carbon atoms, m is an integer of 0-4, R ³¹ and R ³² independently represent hydroxyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy Group, second butoxy group, third butoxy group or chlorine atom]

In a preferred embodiment of the present invention, the dicarboxylic acid compound is a compound represented by formula (3") in which m is 0. As the dicarboxylic acid compound, in addition to the compound represented by formula (3'') where m is 0, it is more preferable to use a compound represented by formula (3'') where A is an oxygen atom. Furthermore, in another preferred embodiment, the dicarboxylic acid compound is a compound represented by formula (3") in which R ³¹ and R ³² are chlorine atoms. In addition, a diisocyanate compound may be used instead of the diamine compound.

As a diamine compound used for manufacturing a resin, aliphatic diamine, aromatic diamine, and mixtures of these can be mentioned, for example. Furthermore, in this embodiment, the so-called "aromatic diamine" means a diamine in which an amine group is directly bonded to an aromatic ring, and a part of its structure may also contain an aliphatic group or other substituents. The aromatic ring may be a monocyclic ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a sulphur ring, but should not be limited to these. Among these, a benzene ring is preferred. In addition, the term "aliphatic diamine" refers to a diamine in which an amine group is directly bonded to an aliphatic group, and a part of the structure may contain an aromatic ring or other substituents.

As aliphatic diamines, for example, acyclic aliphatic diamines such as hexamethylene diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl) Group) cyclohexane, nor-diamine and 4,4'-diaminodicyclohexylmethane and other cyclic aliphatic diamines. These can be used alone or in combination of two or more.

Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2 ,6-Diaminonaphthalene and other aromatic diamines with one aromatic ring, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'- Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diamine Diphenyl benzene, 3,3'-diamino diphenyl benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, double [4-(4-Aminophenoxy)phenyl] ash, bis[4-(3-aminophenoxy)phenyl] ash, 2,2-bis[4-(4-aminophenoxy) Yl)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethane) Phenyl)-4,4'-diaminobiphenyl (sometimes referred to as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminobenzene) Group) 茀, 9,9-bis(4-amino-3-methylphenyl) 茀, 9,9-bis(4-amino-3-chlorophenyl) 茀, 9,9-bis(4 -Amino-3-fluorophenyl) Aromatic diamines having two or more aromatic rings, such as chlorophyll. These can be used alone or in combination of two or more.

The aromatic diamine is preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl ether, 4,4'-diaminodiphenyl benzene, 3,3'-diaminodiphenyl benzene, 1,4-bis(4-aminophenoxy)benzene, bis[4 -(4-Aminophenoxy) phenyl] ash, bis[4-(3-aminophenoxy) phenyl] ash, 2,2-bis[4-(4-aminophenoxy) Phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4 ,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylene, 1,4-bis(4-aminophenoxy) Benzene, bis[4-(4-aminophenoxy)phenyl] sulfide, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethyl Benzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl. These can be used alone or in combination of two or more.

Among the above-mentioned diamine compounds, from the viewpoints of high surface hardness, high transparency, high flexibility, high bending resistance, and low coloring properties of the optical film, it is preferable to use aromatic diamine compounds having a biphenyl structure. One or more of the group consisting of amines. More preferably, use selected from 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-diaminodiphenyl ether is composed of more than one kind, and more preferably 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB ).

Examples of the tetracarboxylic acid compound used for the production of the resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride, and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. The tetracarboxylic acid compound may be used alone or in combination of two or more kinds. In addition to the dianhydride, the tetracarboxylic acid compound may be a tetracarboxylic acid compound analog such as a chlorine compound.

Specific examples of aromatic tetracarboxylic dianhydrides include: non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic tetracarboxylic dianhydrides Acid dianhydride. Examples of non-condensed polycyclic aromatic tetracarboxylic dianhydrides include: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid Dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3' -Biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2 -Bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene )Diphthalic dianhydride (sometimes referred to as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl) ) Ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3, 4-Dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride, 4, 4'-(m-phenylenedioxy) diphthalic dianhydride. Moreover, as the monocyclic aromatic tetracarboxylic dianhydride, for example, 1,2,4,5-benzenetetracarboxylic dianhydride can be cited; as the condensed polycyclic aromatic tetracarboxylic dianhydride, for example, Enumerate: 2,3,6,7-naphthalenetetracarboxylic dianhydride.

Among them, preferably, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride , 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-di Carboxyphenyl) propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis( 3,4-Dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, double (2,3-Dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy) diphthalic dianhydride and 4,4'-(m-phenylenedioxy) Diphthalic dianhydride, more preferably: 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2' ,3,3'-Biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), bis(3,4-dicarboxyphenyl)methane Dianhydride and 4,4'-(p-phenylenedioxy) diphthalic dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or acyclic aliphatic tetracarboxylic dianhydride. The so-called cyclic aliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure. Specific examples thereof include: 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride and other cycloalkane tetracarboxylic dianhydrides, bicyclic [2.2.2]octane -7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride and their positional isomers. These can be used alone or in combination of two or more. Specific examples of acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butane tetracarboxylic dianhydride and 1,2,3,4-pentane tetracarboxylic dianhydride, etc. These can be used alone or in combination of two or more. In addition, cycloaliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride may be used in combination.

Among the above-mentioned tetracarboxylic dianhydrides, from the viewpoints of high surface hardness, high transparency, high flexibility, high buckling resistance, and low coloration of the optical film, 4,4'-oxydiphthalene is preferred Dicarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3, 3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 4 ,4'-(hexafluoroisopropylidene)diphthalic dianhydride and mixtures thereof, more preferably 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4 '-(Hexafluoroisopropylidene) diphthalic dianhydride and mixtures thereof, and more preferably 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA ).

As the dicarboxylic acid compound used to produce the resin, terephthalic acid, 4,4'-oxybisbenzoic acid, or these chlorinated compounds can be preferably used. In addition to terephthalic acid or 4,4'-oxybisbenzoic acid or these chlorine compounds, other dicarboxylic acid compounds can also be used. Examples of other dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and these related chlorinated compounds, acid anhydrides, etc., and two or more of them can be used in combination. Specific examples include: isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; chain hydrocarbon dicarboxylic acid with carbon number 8 or less An acid compound and two benzoic acids are connected via a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene, and the compound And other chlorinated compounds. As a specific example, 4,4'-oxybis(benzoic acid chloride) and terephthalic acid chloride are preferred, and 4,4'-oxybis(benzoic acid chloride) and terephthalic acid chloride are more preferred. Formaldehyde and chlorine are used in combination.

Furthermore, the above-mentioned polyimide-based resins may be used in addition to the above-mentioned tetracarboxylic acid compounds within the range that does not impair the various physical properties of the optical components, and further use tetracarboxylic acids, tricarboxylic acids, and these anhydrides and derivatives The result of the reaction.

Examples of tetracarboxylic acids include water adducts of anhydrides of the above-mentioned tetracarboxylic acid compounds.

Examples of tricarboxylic acid compounds include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, and these related chlorinated compounds, acid anhydrides, and the like, and two or more of them can be used in combination. Specific examples include: anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and benzoic acid via a single bond,- O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -or phenylene-linked compound.

In the production of the resin, the usage amount of the diamine compound, the tetracarboxylic acid compound and/or the dicarboxylic acid compound can be appropriately selected according to the required ratio of each structural unit of the polyimide resin.

In the production of the resin, the reaction temperature of the diamine compound, the tetracarboxylic acid compound, and the dicarboxylic acid compound is not particularly limited, and is, for example, 5 to 350°C, preferably 20 to 200°C, and more preferably 25 to 100°C. The reaction time is also not particularly limited, and it is, for example, about 30 minutes to 10 hours. If necessary, the reaction can be carried out under an inert gas environment or under reduced pressure. In a preferred aspect, the reaction is carried out while stirring under normal pressure and/or an inert gas environment. Furthermore, the reaction is preferably carried out in a solvent that is inert to the reaction. The solvent is not particularly limited as long as it does not affect the reaction. Examples include water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and 1-methoxy Alcohol solvents such as -2-propanol, 2-butoxyethanol, propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, γ-valerolactone , Propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone and other ketone solvents; pentane , Hexane, heptane and other aliphatic hydrocarbon solvents; alicyclic hydrocarbon solvents such as ethyl cyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ethers such as tetrahydrofuran and dimethoxyethane Solvents; chlorinated solvents such as chloroform and chlorobenzene; amine-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; dimethyl sulfide, dimethyl sulfide, Sulfur-containing solvents such as cyclobutane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations (mixed solvents) of these. Among these, from the viewpoint of solubility, an amide-based solvent can be preferably used.

In the imidization step in the production of polyimide resins, imidization can be carried out in the presence of an imidization catalyst. Examples of the imidization catalyst include: aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, N -Alicyclic amines such as butylpyrrolidine, N-butylpiperidine and N-propylhexahydroazepine (monocyclic); azabicyclo[2.2.1]heptane, azabicyclo[3.2.1 ]Octane, azabicyclo[2.2.2]octane and azabicyclo[3.2.2]nonane and other alicyclic amines (polycyclic); and pyridine, 2-methylpyridine (2-methylidine) , 3-methylpyridine (3-methylidine), 4-methylpyridine (4-methylidine), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine Aromatic amines such as pyridine, 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and isoquinoline. Furthermore, from the viewpoint of facilitating the promotion of the imidization reaction, it is preferable to use the imidization catalyst and acid anhydride together. The acid anhydrides include commonly used acid anhydrides used in the imidization reaction, and specific examples thereof include aliphatic anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic anhydrides such as phthalic anhydride. .

Polyimide resins can be isolated (separated and refined) by conventional methods, such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography and other separation methods, or a combination of these separation methods. In a preferred aspect, a large amount of alcohol such as methanol is added to the reaction liquid containing the transparent polyimide resin to precipitate the resin, and the resin can be isolated by concentration, filtration, drying, etc.

The polyimide resin powder produced by the production method of the present invention can be used, for example, as an optical member. As an optical member, an optical film is mentioned, for example. Since this optical member is excellent in flexibility, flex resistance, and surface hardness, it is suitable for use as a front panel of an image display device, especially a front panel of a flexible display (hereinafter sometimes referred to as a window film). The optical member may be a single layer or multiple layers. When the optical member has multiple layers, each layer may have the same composition or different compositions.

When an optical member is obtained by using the polyimide resin powder manufactured by the manufacturing method of the present invention, the content of the polyimide resin in the optical member relative to the total mass of the optical member is preferably It is 40% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more, and usually 100% by mass or less. If the content of the polyimide-based resin is greater than or equal to the above lower limit, the flexural resistance of the optical member is good.

(Inorganic material) In addition to the polyimide-based resin, the optical member may further contain inorganic materials such as inorganic particles. Examples of the inorganic material include inorganic particles such as titanium oxide particles, aluminum oxide particles, zirconium oxide particles, and silicon oxide particles, and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate. From the viewpoint of the stability of the varnish containing the polyimide-based resin used to manufacture the optical member, the inorganic material is preferably inorganic particles, and among them, silicon oxide particles are preferred. Inorganic particles can be combined with each other by molecules with siloxane bonds.

The average primary particle size of the inorganic particles is generally 1-100 nm or more, preferably 5 to 80 nm, more preferably 7-50 nm from the viewpoints of transparency of the optical member, mechanical properties, and inhibition of the aggregation of inorganic particles. , More preferably 10-30 nm. In the present invention, the average primary particle size can be determined by measuring the 10-point average value of the directional diameter based on the transmission electron microscope.

Regarding the content rate of the inorganic material in the optical member, based on the total mass of the optical member, it is preferably 0% by mass or more and 90% by mass or less, more preferably 0.01% by mass or more and 60% by mass or less, and more preferably 5 More than 40% by mass. If the content of the inorganic material is within the above range, there is a tendency that the optical member has both transparency and mechanical properties.

(Ultraviolet absorber) The optical member may contain one kind or two or more kinds of ultraviolet absorbers. The ultraviolet absorber can be appropriately selected from those generally used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may include a compound that absorbs light with a wavelength below 400 nm. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone compounds, salicylate compounds, benzotriazole compounds, and triazole compounds. By containing the ultraviolet absorber in the optical member, the deterioration of the polyimide-based resin is suppressed, and therefore the visibility of the optical member can be improved. In addition, in this specification, the term "system compound" refers to a derivative of the compound whose index indicates the "system compound". For example, the so-called "benzophenone-based compound" refers to a compound having benzophenone as the parent skeleton and a substituent bonded to the benzophenone.

When the optical member contains an ultraviolet absorber, the content of the ultraviolet absorber relative to the total mass of the optical member is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 3% by mass or more, And it is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass or less. The appropriate content varies with the UV absorber used. If the content of the UV absorber is adjusted so that the light transmittance of 400 nm becomes about 20-60%, the light resistance of the optical member can be improved and transparency can be obtained. Optical components with high performance.

(Other additives) The optical member may further contain other additives. Examples of other components include antioxidants, release agents, stabilizers, bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, and levelers.

The content of other additives relative to the mass of the optical member is preferably from 0% by mass to 20% by mass, and more preferably from 0% by mass to 10% by mass.

The thickness of the optical member and the optical film therein is appropriately adjusted according to the application, and is usually 10 to 1,000 μm, preferably 15 to 500 μm, more preferably 20 to 400 μm, and still more preferably 25 to 300 μm. Furthermore, in the present invention, the thickness can be measured with a contact type digital gauge.

The total light transmittance Tt of the optical component is preferably 70% or more, more preferably 80% or more, further preferably 85% or more, particularly preferably 90% or more, and usually 100% or less. If the total light transmittance Tt of the optical member is greater than or equal to the above lower limit, it is easy to ensure sufficient visibility when the optical member is assembled into an image display device. The total light transmittance is measured using a haze meter in accordance with JIS K 7361-1:1997, for example. The haze of the optical member is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, still more preferably 0.8% or less, particularly preferably 0.5% or less, especially more preferably 0.3 % Or less, and usually 0% or more. If the haze of the optical member is below the above upper limit, it is easy to ensure sufficient visibility when the optical member is assembled into a flexible electronic device such as an image display device. In addition, the haze can be measured using a haze meter in accordance with JIS K 7105:1981. Polyimine resin dissolved in the polyimide resin solution (a) used in the production method of the present invention, and/or powder of the polyimide resin obtained by the production method of the present invention It is preferable to have the above-mentioned total light transmittance Tt and/or haze. The total light transmittance Tt and/or haze of the polyimide-based resin and the polyimide-based resin powder is measured by the shape of the molded body, for example, the film.

(Method of manufacturing optical components) Using the polyimide-based resin powder manufactured by the manufacturing method of the present invention, the above-mentioned optical member, such as an optical film, can be manufactured. The manufacturing method is not particularly limited. For example, by including the following steps: (a) A step of forming a coating film by coating a solution containing polyimide resin (polyimide resin varnish) obtained by dissolving polyimide resin powder in a solvent on a substrate (coating Cloth steps), and (b) The step of drying the applied solution (polyimide resin varnish) to form an optical member and the optical film (polyimide resin film) (forming step) The manufacturing method of manufacturing optical components. Steps (a) and (b) can usually be carried out in this order.

In the coating step, the polyimide resin powder is dissolved in a solvent, the above-mentioned ultraviolet absorber and other additives are added as necessary, and stirred, thereby preparing a solution containing polyimide resin (polyimide resin). Varnish of resin).

The solvent used for preparing the varnish is not particularly limited as long as it can dissolve the polyimide resin. Examples of the solvent include: amide-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; lactone-based solvents such as γ-butyrolactone and γ-valerolactone Solvents; sulfur-containing solvents such as dimethyl sulfide, dimethyl sulfide, and cyclobutyl sulfide; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof. Among these solvents, from the viewpoint of solubility, an amide-based solvent or a lactone-based solvent is preferred. In addition, water, alcohol-based solvents, ketone-based solvents, acyclic ester-based solvents, ether-based solvents, etc. may be contained in the varnish.

Then, for example, a well-known roll-to-roll or batch method can be used, using a varnish of a polyimide resin, and forming a coating film on a substrate such as a resin substrate, SUS tape, or glass substrate by casting.

In the forming step, the coating film is dried and then peeled from the base material, whereby the optical member can be formed. After the peeling, a drying step of drying the optical member can be further performed. The drying of the coating film can usually be carried out at a temperature of 50 to 350°C. If necessary, the coating film can be dried in an inert gas environment or under reduced pressure.

It is also possible to perform a surface treatment step of performing surface treatment on at least one surface of the optical component. Examples of surface treatments include UV ozone treatment, plasma treatment, and corona discharge treatment.

As an example of a resin substrate, PET film, PEN film, polyimide film, polyimide imide film, etc. are mentioned. Among them, from the viewpoint of excellent heat resistance, PET films, PEN films, polyimide films, and other polyimide films are preferred. Furthermore, from the viewpoint of adhesion to an optical member and cost, a PET film is more preferable.

Using the polyimide resin powder obtained by the manufacturing method of the present invention, an optical member can be manufactured. This kind of optical component has high elastic modulus and flexibility. In a preferred embodiment of the present invention, the elastic modulus of the above-mentioned optical member is preferably 3.0 GPa or more, more preferably 4.0 GPa or more, still more preferably 5.0 GPa or more, particularly preferably 6.0 GPa or more, and more preferably It is 10.0 GPa or less, more preferably 8.0 GPa or less, and still more preferably 7.0 GPa or less. If the elastic modulus of the optical member is below the above upper limit, when the flexible display is bent, damage to other members caused by the above optical member can be suppressed. For the modulus of elasticity, for example, Autograph AG-IS manufactured by Shimadzu Corporation, for a test piece with a width of 10 mm, the stress-strain curve can be measured at a distance between the chucks of 50 mm and a tensile speed of 20 mm/min ( Hereinafter, it may be referred to as SS curve), and it is measured from its slope. Polyimine resin dissolved in the polyimide resin solution (a) used in the production method of the present invention, and/or powder of the polyimide resin obtained by the production method of the present invention It preferably has the above-mentioned elastic modulus. The modulus of elasticity of the polyimide resin and the polyimide resin powder is measured by the shape of the molded body, for example, the film. The preparation method of the measurement sample and the detailed description of the measurement method are as described in the examples.

The above-mentioned optical member and the optical film therein have excellent flexural resistance. In a preferred embodiment of the present invention, when the optical member is subjected to R=1 mm and 135° bending measurement at a speed of 175 cpm under a load of 0.75 kgf, the number of reciprocating bending times until breaking is preferably 10,000 or more. It is more preferably 20,000 times or more, still more preferably 30,000 times or more, still more preferably 40,000 times or more, and particularly preferably 50,000 times or more. If the number of reciprocating bending of the optical member is more than the above lower limit, wrinkles that may be generated when the optical member is bent can be further suppressed. Furthermore, there is no limit to the number of reciprocating bending of the optical member. Generally, as long as it can be bent 1,000,000 times, it has sufficient practicality. The number of reciprocating bending times can be obtained, for example, using a test piece (optical member) having a thickness of 50 μm and a width of 10 mm using an MIT bending fatigue tester (model 0530) manufactured by Toyo Seiki Seisakusho Co., Ltd. Polyimine resin dissolved in the polyimide resin solution (a) used in the production method of the present invention, and/or powder of the polyimide resin obtained by the production method of the present invention It is preferable to have the above-mentioned flexural resistance. The flexural resistance of the polyimide resin and the polyimide resin powder is measured by the shape of the molded body (for example, a film).

The above-mentioned optical member can exhibit excellent transparency. Therefore, the above-mentioned optical member is very useful as an image display device, especially a front panel (window film) of a flexible display. In a preferred embodiment of the present invention, the YI value of the optical member according to JIS K 7373:2006 is preferably 5 or less, more preferably 3 or less, further preferably 2.5 or less, particularly preferably 2.0 or less, and generally 0 or more. An optical member whose YI value is less than the above upper limit contributes to achieving high visibility of display devices and the like. Polyimine resin dissolved in the polyimide resin solution (a) used in the production method of the present invention, and/or powder of the polyimide resin obtained by the production method of the present invention It preferably has the above-mentioned YI value. The YI value of the polyimide resin and the polyimide resin powder is measured by the shape of the molded body, for example, the film. The preparation method of the measurement sample and the detailed description of the measurement method are as described in the examples.

The above-mentioned optical member may include functional layers such as an ultraviolet absorbing layer, an adhesive layer, a hue adjustment layer, and a refractive index adjustment layer, and a hard coat layer.

Optical components such as optical films manufactured using the polyimide resin powder of the present invention are used as the front panel of an image display device, especially the front panel of a flexible display, especially the window film of a windable display or a foldable display it works. The above-mentioned optical member can be used as a front panel to be arranged on the visible side surface of an image display device, especially a flexible display. The front panel has the function of protecting the image display elements in the flexible display. The image display device equipped with the above-mentioned optical components has high flexibility and flex resistance, and at the same time has high surface hardness, so it will not damage other components when bending, and the optical components themselves are not prone to wrinkles, and thus The surface damage can be advantageously suppressed.

Examples of image display devices include wearable devices such as televisions, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, meters, bulletin boards, clocks, and smart watches. Examples of flexible displays include image display devices with flexible characteristics, such as televisions, smart phones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, gauges, bulletin boards, clocks, and Wearable devices, etc. [Example]

Hereinafter, the present invention will be explained in more detail through examples. As long as there is no special record, the "%" and "parts" in the examples mean mass% and mass parts. First, the evaluation method will be explained.

(Determination of weight average molecular weight (Mw)) Gel permeation chromatography (GPC) was used for the determination. The preparation method and measurement conditions of the measurement sample are as follows. (1) Sample preparation method Weigh 20 mg of resin and add 10 mL of DMF (10 mmol/LM lithium bromide) to completely dissolve it. This solution was filtered using a chromatography disc (pore size 0.45 μm) to prepare a sample solution. (2) Measurement conditions Device: HLC-8020GPC String: protection string + TSKgelα-M (300 mm×7.8 mm diameter)×2 pieces +α-2500 (300 mm×7.8 mm diameter)×1 pieces Eluent: DMF (add 10 mmol/L lithium bromide) Flow rate: 1.0 mL/min Detector: RI detector Column temperature: 40℃ Injection volume: 100 μL Molecular weight standard: standard polystyrene

(Measurement of chromaticity) The polyimide resin powder is put into a petri dish as a measurement sample. The color difference meter "CR-5" manufactured by Konica Minolta Co., Ltd. is used to measure the color under the following measurement conditions Degree (according to JIS Z 8781-4:2013). <Measurement conditions> Observation conditions: 2° field of view (CIE1931) Observation light source: C Color system: L ^＊ a ^＊ b ^＊ Color space color difference formula: ΔE ^＊ ab (CIE1976) Color difference formula index: No measurement type: Petri dish measurement measurement Diameter Φ: 30 mm

(Confirmation of the solubility of resin in solvent) Regarding the resin powder described in Synthesis Example 1 below, the solubility in the solvent was confirmed by the following method. Weigh 9.9 g of solvent into a 30 mL glass spiral tube, and then place it on a magnetic stirrer for stirring. 0.1 g of resin powder was added thereto, and the mixture was stirred at room temperature (24°C) for 3 hours to confirm the solubility. As a result, the resin powder was dissolved in DMAc, but not dissolved in methanol and ion exchange water. Therefore, DMAc is a good solvent, and methanol and ion exchange water are poor solvents.

(Measurement of Angle of Repose) The polyimide resin powder is passed through a 710 μm sieve from a funnel of a certain height and then dropped onto a horizontal substrate. The bus bar of the polyimide resin powder piled in a cone shape on the substrate is measured. The angle formed by the surface of the substrate serves as the angle of repose. Measuring device: powder tester PT-X (manufactured by Hosokawa Micron Co., Ltd.)

(Image analysis of polyimide resin powder) For polyimide resin powder, a digital microscope (VHX-2000) manufactured by KEYENCE Co., Ltd. was used to obtain an optical microscope image at a magnification of 100 times. The image size is set to 1,600 pixel×1,200 pixel, and the pixel size is set to 2.2 μm/pixel. Transfer the obtained optical microscope image to a computer, and use image analysis software Image J to perform image processing. Binarization is performed based on the intermediate value of the maximum brightness and the minimum brightness in the image, and it is visually confirmed that the area corresponding to the particle image of the polyimide resin powder has been successfully separated from the other areas. In order to be able to analyze accurately, the binary image is filled (Fill Holes). After that, in order to exclude the incomplete polyimide resin powder particles located at the end of the image from the particle analysis, perform Analyze Particles under the condition of Exclude on edges, and calculate The perimeter, area, and center of gravity coordinates of particles of more than 100 polyimide resin powders. Calculate the obtained average perimeter and area, and set the average perimeter (A μm) and average area (B μm ² ) of the particles of the polyimide-based resin powder, respectively. Next, use the data analysis software Igor Pro to read the image after the above processing, and perform Image Analyze Particles to obtain the surface points (points on the outline) of each particle of the polyimide resin powder The coordinates. From the coordinates of the center of gravity and the coordinates of each point on the surface, the center of gravity-surface distance curve of each particle is obtained. According to the center of gravity-surface distance curve, calculate the average value of the center of gravity-surface distance, that is, the equivalent circle radius of one particle (Zc' μm) and the surface roughness of one particle (Ra' μm). Then, calculate the average circle equivalent radius (Zc' μm) and surface roughness (Ra' μm) obtained for more than 100 particles, and set it as the average circle equivalent of the particles of the polyimide resin powder Radius (Zc μm) and particle surface roughness (Ra μm). Also, from the obtained results, the ratio of the surface roughness Ra of the particles to the average circle equivalent radius Zc (Ra/Zc) was calculated.

(Evaluation of the production of aggregates during the production of varnish (evaluation of aggregation)) [Production of γ-butyrolactone (GBL) dispersed silica sol] 327.9 parts of methanol-dispersed silica sol (primary particle size 25 nm, solid content of silica 30.5 mass%) and 223.4 parts of γ-butyrolactone (GBL) were put into the reaction vessel. The temperature in the vessel was set to 45°C, the pressure in the reaction vessel was set to 400 hPa and maintained for 1 hour, and then the pressure in the reaction vessel was set to 250 hPa and maintained for 1 hour to evaporate the methanol. Furthermore, the pressure in the reaction vessel was set to 250 hPa, and the temperature in the vessel was raised to 70°C and heated for 30 minutes. As a result, GBL dispersed silica sol was obtained. The solid content of the obtained GBL dispersed silica sol was 28.9% by mass. [Production of varnish solution] Add GBL-dispersed silica sol, Sumisorb (registered trademark) 340 as a UV absorber, and Sumiplast (registered trademark) Violet B as a brightener to the γ-butyrolactone in the reaction vessel to make a uniform solution and then flow into it. The polyimide resin powders produced in Examples 1, 2 and Comparative Examples were prepared into varnish solutions so that the solid content became 10.2%. The mass ratio of polyimide resin and silica is 60:40, and Sumisorb 340 is 5.5 parts with respect to 100 parts of the total amount of polyimide resin and silica. Sumiplast Violet B is 35 ppm based on the total amount of polyimide resin and silica. [Evaluation of Agglutination] After transferring the varnish solution in the reaction vessel to another vessel, visually observe the condition of the residue in the reaction vessel. The aggregation properties were evaluated based on the following criteria. ○: After taking out the varnish solution from the reaction vessel, no solid matter remains in the vessel. ×: After the varnish solution was taken out from the reaction container, solid matter remained in the container.

(Evaluation of the solubility of polyimide resin powder) Weigh 19.4 g of DMAc into a glass spiral tube with a volume of 50 mL. Then, while stirring the DMAc with a magnetic stirrer, 0.6 g of polyimide-based resin powder was poured into the DMAc. The state of the solution after 1 hour after mixing of the powder was observed, and the solubility was evaluated based on the following evaluation criteria. [Evaluation of solubility] ○: The solution is transparent and has good solubility. ×: The solution is opaque and has poor solubility.

[Example 1] Nitrogen gas is introduced into the fully dried reaction vessel equipped with a stirrer and a thermometer, and the inside of the vessel is replaced with nitrogen. Add 1907.2 parts of dimethylacetamide (DMAc) to the container, add 111.94 parts of 2,2'-bis(trifluoromethyl)benzidine (TFMB) and 4,4'-(hexafluoroisopropylidene) 46.84 parts of diphthalic dianhydride (6FDA) were reacted. Then, 10.37 parts of 4,4'-oxybis(benzyl chloride) (OBBC) and 42.79 parts of terephthalate chloride (TPC) were added and reacted. Then, 37.66 parts of acetic anhydride was added, and after stirring for 15 minutes, 11.45 parts of 4-methidine was added, and the reaction vessel was heated to 70° C., and further stirred for 3 hours to obtain a reaction liquid. The reaction solution was cooled down to below 40°C, while stirring the reaction solution by rotating the stirring blade (diameter 750 mm) at a rotation speed of 74.4 rpm and a tip speed of 2.92 m/sec, 3794.5 parts of methanol was added dropwise to the reaction solution , Then 1419.4 parts of ion-exchanged water was added dropwise to precipitate a white solid. The precipitated white solid was collected by centrifugal filtration and washed with methanol, thereby obtaining a wet cake containing polyimide resin. The obtained wet cake was dried at 78°C under reduced pressure, thereby obtaining polyimide resin powder (1).

[Example 2] When methanol and ion-exchanged water were added dropwise to the reaction solution, the rotation speed of the stirring blade was changed to 74.6 rpm, and the tip speed was changed to 2.93 m/sec, except that the polyamide was obtained in the same manner as in Example 1. Imine resin powder (2).

[Comparative Example 1] Nitrogen gas is introduced into the fully dried reaction vessel equipped with a stirrer and a thermometer, and the inside of the vessel is replaced with nitrogen. Add 1907.2 parts of DMAc, 111.94 parts of TFMB and 46.82 parts of 6FDA to the container, and stir. Then, 10.37 parts of OBBC and 38.54 parts of TPC were added and stirred. 1907.2 parts of DMAc and 4.3 parts of TPC were added to the produced reaction liquid, and it stirred. Then, 31.80 parts of diisopropylethylamine and 75.32 parts of acetic anhydride were added, and after stirring for 30 minutes, 22.90 parts of 4-methylpyridine was added, and the reaction vessel was heated to 75° C. and stirred for 3 hours to obtain a reaction liquid. The reaction solution was cooled down to below 40°C, while the stirring blade (diameter 850 mm) was rotated at 85 rpm and the tip speed of 3.78 m/sec to stir the reaction solution, 5722.2 parts of methanol was added dropwise to the reaction solution Then, 2861.7 parts of ion-exchanged water was added dropwise to precipitate a white solid. The precipitated white solid was collected by centrifugal filtration and washed with methanol, thereby obtaining a wet cake containing polyimide resin. The obtained wet cake was dried at 78°C under reduced pressure, thereby obtaining polyimide resin powder (3).

For polyimide resin powders (1)～(3), measure the weight average molecular weight, chroma, angle of repose, the average perimeter (A μm) and average area of the resin powder particles based on image analysis (B μm ² ), the ratio of the square of A to B (A ² /B), surface roughness (Ra μm), average circle equivalent radius (Zc μm), the ratio of Ra to Zc (Ra/Zc). In addition, the agglutinability and solubility were evaluated based on the aforementioned evaluation criteria. The obtained results are shown in Table 1 and Table 2.

[Table 1] Weight average molecular weight Angle of repose [°] Average circumference [μm] Average area [μm ² ] A ² /B Agglutination Solubility Example 1 418,000 33.4 910 39,228 21.11 〇 〇 2 365,000 35.4 1,062 48,189 23.40 〇 〇 Comparative example 1 357,000 39.8 1,039 31,929 33.81 X 〇

[Table 2] Chroma Ra [μm] Zc [μm] Ra/Zc L* a* b* Example 1 98.50 -3.13 7.41 16.77 111.1 0.151 2 98.65 -3.11 7.24 22.05 125.3 0.176 Comparative example 1 97.59 -2.53 7.11 20.18 102.4 0.197

As shown in Table 1 and Table 2, the polyimide resin powders of Examples 1 and 2 were obtained while rotating the stirring blade to stir the reaction solution under the condition that the tip speed was 3.40 m/sec or less. The angle of repose of the imide-based resin powder is 37.0° or less, and the ratio (A ² /B) is 14.0-30.0. It is confirmed that it is a polyamide that is not easy to agglomerate when preparing a varnish and has high solubility in the varnish. Amine resin powder. On the other hand, the polyimide-based resin powder was precipitated while the stirring blade was rotated under the condition that the tip speed exceeded 3.40 m/sec and 3.78 m/sec to agitate the reaction liquid. As a result, the polymer of Comparative Example 1 was obtained. The angle of repose of the imine-based resin powder exceeds 37.0°, and the ratio (A ² /B) exceeds 30.0. Although the polyimide resin powder system has good solubility in the varnish, it is a powder that is easy to agglomerate when preparing the varnish.

Figure 1 (a) ~ (c) are diagrams for explaining the method of particle image analysis.

Claims (8)

A polyimide-based resin powder whose angle of repose is 37.0° or less. If the average perimeter of the particles of the polyimide-based resin powder calculated by image analysis is set to A μm and the average area is set to B μm ² , the ratio of the square of A to B (A ² /B) is 14.0-30.0. The polyimide resin powder of claim 1, wherein if the surface roughness of the particles of the polyimide resin powder calculated by image analysis is set to Ra μm, and the average circle equivalent radius is set to Zc μm, the ratio of Ra to Zc (Ra/Zc) does not reach 0.19. The polyimide resin powder of claim 1 or 2, wherein the average area of particles (B μm ² ) of the polyimide resin powder calculated by image analysis is 2,000 to 500,000 μm ² . The polyimide resin powder of any one of claims 1 to 3, wherein the average circle equivalent radius (Zc μm) of the particles of the polyimide resin powder calculated by image analysis is 50 ~800 μm. The polyimide resin powder according to any one of claims 1 to 4, wherein the weight average molecular weight of the polyimide resin is 200,000 or more. Such as the polyimide resin powder of any one of claims 1 to 5, wherein the chromaticity of the polyimide resin powder satisfies L in the color difference measurement based on the L ^* a ^* b ^* color system ^＊ ≧90, -10≦a ^＊ ≦10 and -10≦b ^＊ ≦10. A manufacturing method of polyimide resin powder, which at least includes the following steps: one side is prepared by dissolving polyimide resin in a good solvent under the condition that the speed of the front end of the stirring blade is below 3.40 m/sec. While stirring the resin solution, at least one poor solvent is added to the resin solution to precipitate the polyimide resin. The method for producing polyimide resin powder according to claim 7, wherein the rotation speed of the stirring blade in the stirring is 100 rpm or less.

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