TWI775946B - Polyimide powder, polyimide coating and polyimide film - Google Patents

Abstract

The present invention is a polyimide powder, which is composed of a mixture of polyimide powder A and polyimide powder B, and is a polyimide powder soluble in organic solvents. It is characterized in that the polyimide powder A and the polyimide powder B are respectively composed of a structural unit derived from at least one kind of aromatic diamine compound and a structural unit derived from at least one kind of tetracarboxylic dianhydride. It is composed of polyimide, and the polyimide powder A is composed of (a-1) a reduced viscosity of 1.2 dL/g or more and less than 2.1 dL/g, or (a-2) 100,000 g/mol or more and It is composed of polyimide with a weight-average molecular weight of less than 250,000 g/mol, and the polyimide powder B has a reduced viscosity of (b-1) 2.1 dL/g or more and 3.0 dL/g or less, or (b -2) It is composed of polyimide with a weight average molecular weight of 250,000 g/mol or more and 500,000 g/mol or less, and the weight ratio of polyimide powder A/polyimide powder B is 10/90～90/ In the range of 10, the reduced viscosity measured for the mixture of polyimide powder A and polyimide powder B is in the range of 1.7 to 2.5 dL/g, or for polyimide powder A and polyimide powder B The weight average molecular weight measured by mixing the amine powder B is in the range of 160,000 to 350,000 g/mol. The polyimide powder is soluble in organic solvents and has excellent handleability. Coatings dissolved in an organic solvent at a concentration give a polyimide film with excellent heat resistance, transparency and mechanical properties.

Description

Polyimide powder, polyimide coating and polyimide film

The present invention relates to polyimide powders and polyimide coatings and polyimide films obtained by using the same, especially for use in display applications or electronic material applications, providing both extremely excellent heat resistance and transparency. Polyimide powder and polyimide coating of polyimide film.

Polyimide resins, as polymers with excellent heat resistance, are used in a wide range of fields requiring heat resistance or high reliability, such as aerospace, electrical insulation, and electronics. In addition, in recent years, transparent polyimide having both heat resistance and transparency has been proposed. For example, Patent Document 1 proposes a soluble polyimide, which is synthesized from a specific monomer containing a fluorine atom and is suitable for optical waveguides and has excellent transparency. imine. Patent Document 2 proposes a transparent polyimide that is soluble in an organic solvent using a specific alicyclic diamine. However, Patent Document 1 and Patent Document 2 do not disclose the polyimide powder, and since the polyimide described in Patent Document 2 uses an alicyclic diamine as a raw material, it lacks heat resistance and has Problems with coloring due to heating.

As a powder of polyimide, a method of depositing a block-shaped polyimide resin by adding a poor solvent such as water or methanol to a coating material of soluble polyimide is disclosed (Patent Document 3).

Moreover, in patent document 4, the powder of the imide compound of polyamic acid obtained by polymerizing diamines and acid dianhydrides is proposed.

However, the powder of the polyimide described in Patent Document 3 or Patent Document 4 is based on the fact that the molar amount of the diamines and the molar amount of the acid anhydride are basically the same as the raw material monomers. However, in the case of such a production method, the degree of polymerization of the polyamic acid greatly varies due to only the weighing error of the monomer, the dissolved residue of the monomer, and the fluctuation of the purity of the monomer. As a result, there is a problem that the degree of polymerization of the obtained polyimide powder cannot be stabilized. In order to prevent this, a method of polymerizing polyamic acid by slightly shifting the molar ratio of diamine and acid anhydride from 1 is adopted. However, even in this case, it is affected by the amount of water contained in the solvent. Problems that cause changes in the degree of aggregation. In addition, in the stage of the polyamic acid solution, even if it is a solution with the same degree of polymerization, even in the subsequent steps of imidization, powderization, drying, etc., the degree of polymerization may be caused by the splitting of the polymer. Change the situation of the problem.

In this way, when the polyimide powder with varying degrees of polymerization is directly dissolved in a solvent and used as a polyimide solution (coating), the viscosity of the polyimide coating changes significantly, and a stable polyimide film cannot be obtained. film formation, and there is a problem of lowering the mechanical properties of the resulting polyimide film. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 4-235505 [Patent Document 2] Japanese Patent Laid-Open No. 2000-169579 [Patent Document 3] Japanese Patent Laid-Open No. 2004-285355 [Patent Document 4] Japanese Patent Publication 2013-523939

[The problem to be solved by the invention]

The object of the present invention is to provide a polyimide film excellent in heat resistance, transparency and mechanical properties, a polyimide powder and a polyimide coating that are soluble in organic solvents and excellent in handleability. [means to solve the problem]

The present inventors found that by mixing polyimide powder A and polyimide powder B having different reduction viscosities or weight average molecular weights in a specific range of weight ratios, it is possible to obtain heat-resistant, transparent The present invention has been completed by a polyimide film having excellent properties and mechanical properties, a polyimide powder having good handleability, and a polyimide coating.

According to the present invention, a polyimide powder, a polyimide coating material, a method for producing a polyimide coating material, and a polyimide film shown below are provided. [1] A polyimide powder, which is composed of a mixture of polyimide powder A and polyimide powder B, and is a polyimide powder soluble in an organic solvent, which is It is characterized in that the polyimide powder A and the polyimide powder B are respectively composed of a structural unit derived from at least one kind of aromatic diamine compound and a structural unit derived from at least one kind of tetracarboxylic dianhydride. The polyimide powder A is composed of (a-1) a reduced viscosity of 1.2 dL/g or more and less than 2.1 dL/g, or (a-2) 100,000 g/mol or more and It is composed of polyimide with a weight-average molecular weight of less than 250,000 g/mol. -2) It is composed of polyimide with a weight average molecular weight of 250,000 g/mol or more and 500,000 g/mol or less, and the weight ratio of polyimide powder A/polyimide powder B is 10/90～90/ In the range of 10, the reduced viscosity measured for the mixture of polyimide powder A and polyimide powder B is in the range of 1.7 to 2.5 dL/g, or for polyimide powder A and polyimide powder B The weight average molecular weight measured by mixing the amine powder B is in the range of 160,000 to 350,000 g/mol. [2] The polyimide powder according to [1], wherein the polyimide powder A is made of a polyimide powder having (a-1) a reduced viscosity of 1.2 dL/g or more and less than 2.1 dL/g It is composed of polyimide, and the polyimide powder B is composed of (b-1) a polyimide having a reducing viscosity of not less than 2.1 dL/g and not more than 3.0 dL/g. The reduced viscosity measured by mixing A and the polyimide powder B was in the range of 1.7 to 2.5 dL/g. [3] The polyimide powder according to [1], wherein the polyimide powder A has (a-2) a weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol The polyimide powder B is composed of (b-2) a polyimide having a weight average molecular weight of not less than 250,000 g/mol and not more than 500,000 g/mol. The weight average molecular weight measured by mixing the powder A and the polyimide powder B is in the range of 160,000 to 350,000 g/mol. [4] The polyimide powder according to any one of [1] to [3], which is based on the at least one kind of aromatic diamine compound and includes at least one kind of aromatic diamine compound having a fluorine group . [5] The polyimide powder according to any one of [1] to [4], which is based on the aforementioned at least one type of tetracarboxylic dianhydride and contains at least one type of aromatic tetracarboxylic acid having a fluorine group Dianhydride. [6] The polyimide powder according to any one of [1] to [5], wherein the polyimide powder A and the polyimide powder B are composed of a polyimide derived from the same aromatic diamine The structural unit of the compound is composed of a polyimide derived from the structural unit of the same tetracarboxylic dianhydride. [7] The polyimide powder according to any one of [1] to [6], wherein both the polyimide powder A and the polyimide powder B are made of p-polyimide Polymerization, chemical imidization reaction, and polyimide produced by the steps of forming and drying the precipitated powder of polyimide. [8] The polyimide powder according to any one of [1] to [7], wherein the average particle diameter measured for the mixture of the polyimide powder A and the polyimide powder B It is the range of 0.02-0.8mm. [9] The polyimide powder according to any one of [1] to [8], wherein a polyimide film having a thickness of 50 μm obtained by film formation from a solution dissolved in an organic solvent has a concentration of 85% or more The total light transmittance and the yellowness in the range of -3 to 3 (Yellow Index). [10] A polyimide coating, characterized in that the polyimide powder of any one of [1] to [9] is dissolved in an organic solvent at a concentration of 1 to 30% by weight. [11] A method for producing a polyimide paint according to [10], which comprises a paint in which polyimide powder A is dissolved in an organic solvent at a concentration of 1 to 30% by weight, and A paint in which polyimide powder B is dissolved in an organic solvent at a concentration of 1 to 30% by weight, and the weight ratio of polyimide powder A/polyimide powder B is 10/90 to The polyimide powder A is mixed in a 90/10 range, wherein the polyimide powder A is composed of a structural unit derived from at least one kind of aromatic diamine compound and a structure derived from at least one kind of tetracarboxylic dianhydride. unit, and has a reduced viscosity of (a-1) 1.2 dL/g or more and less than 2.1 dL/g, or (a-2) 100,000 g/mol or more and less than 250,000 g/mol It is composed of polyimide having a weight average molecular weight, and the polyimide powder B is composed of a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride. , and has a reduced viscosity of (b-1) 2.1 dL/g or more and 3.0 dL/g or less, or (b-2) a weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol that is soluble in organic solvents of polyimide. [12] The method for producing a polyimide coating material according to [11], wherein the coating material is a coating material obtained by dissolving the polyimide powder A in an organic solvent at a concentration of 1 to 30% by weight, In contrast to the coating material in which the polyimide powder B is dissolved in an organic solvent at a concentration of 1 to 30% by weight, the polyimide powder A is composed of a compound having an aromatic diamine compound derived from at least one species. A structural unit and a structural unit derived from at least one type of tetracarboxylic dianhydride, and having (a-1) a polyimide having a reduced viscosity of 1.2 dL/g or more and less than 2.1 dL/g soluble in an organic solvent Formed, the polyimide powder B is composed of a structural unit derived from at least one kind of aromatic diamine compound and a structural unit derived from at least one kind of tetracarboxylic dianhydride, and has a soluble organic solvent. (b-1) It is composed of polyimide with a reduced viscosity of not less than 2.1dL/g and not more than 3.0dL/g. [13] The method for producing a polyimide coating material according to [11], wherein the coating material is a coating material obtained by dissolving the polyimide powder A in an organic solvent at a concentration of 1 to 30% by weight, In contrast to the coating material in which the polyimide powder B is dissolved in an organic solvent at a concentration of 1 to 30% by weight, the polyimide powder A is composed of a compound having an aromatic diamine compound derived from at least one species. A structural unit and a structural unit derived from at least one type of tetracarboxylic dianhydride, and having a weight-average molecular weight of (a-2) soluble in an organic solvent of 100,000 g/mol or more and less than 250,000 g/mol Consisting of amines, the polyimide powder B has a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride, and is soluble in an organic solvent (b-2) is composed of polyimide having a weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol. [14] A polyimide film, which is obtained from the polyimide coating described in [10]. [15] The polyimide film according to [14], wherein the total light transmittance is 85% or more, and the yellowness is in the range of -3 to 3. [Effect of invention]

According to the present invention, it is possible to provide a polyimide powder and a polyimide coating material that provide a polyimide film having excellent heat resistance or mechanical properties and also excellent in transparency.

The polyimide powder of the first embodiment of the present invention is prepared by mixing the polyimide powder A and the polyimide powder B in a weight ratio, that is, the polyimide powder A/polyimide powder The imide powder B is mixed at a ratio of 10/90 to 90/10, and the reduced viscosity measured for the resulting mixture is adjusted to be in the range of 1.7 to 2.5 dL/g, or the weight measured for the resulting mixture The average molecular weight is adjusted in the range of 160,000 to 350,000 g/mol, and the polyimide powder A is produced by using an aromatic diamine compound and a tetracarboxylic dianhydride (a-1) The reduced viscosity is 1.2 dL/g or more and less than 2.1dL/g of polyimide, or (a-2) polyimide with a weight-average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol, the polyimide The imine powder B is composed of (b-1) polyimide with reduced viscosity of 2.1dL/g or more and 3.0dL/g or less, or (b-2) weight average molecular weight of 250,000g/mol or more and 500,000g/mol It consists of the following polyimide.

The polyimide coating of the second embodiment of the present invention is prepared by mixing polyimide powder A and polyimide powder B in a weight ratio, that is, polyimide powder A/polyimide powder The imine powder B is mixed at a ratio of 10/90 to 90/10, and the reduced viscosity measured for the resulting mixture is adjusted to a range of 1.7 to 2.5 dL/g, or the weight measured for the resulting mixture is adjusted A polyimide powder having an average molecular weight adjusted to a range of 160,000 to 350,000 g/mol is produced by dissolving it in an organic solvent at a concentration of 1 to 30% by weight, and the polyimide powder A is made of (a-1) Reduced viscosity of 1.2 dL/g or more and less than 2.1 dL/g, or (a-2) Weight average molecular weight of 100,000 g/mol, produced using an aromatic diamine compound and tetracarboxylic dianhydride The polyimide powder B is composed of a polyimide of more than 250,000 g/mol and less than 250,000 g/mol. Or (b-2) It consists of polyimide whose weight average molecular weight is 250,000 g/mol or more and 500,000 g/mol or less. In addition, the polyimide coating can also be dissolved in an organic solvent by dissolving the aforementioned polyimide powder A and polyimide powder B in a concentration of 1 to 30%, respectively, and then using the solute as a solution. The polyimide A and the polyimide B were mixed so that the weight ratio of the polyimide A/polyimide B=10/90 to 90/10, and produced.

1. Raw materials 1.1. Aromatic diamine compound As the aromatic diamine compound used for the production of the polyimide powder of the present invention, it can be given by the reaction with the tetracarboxylic dianhydride used in combination. As the aromatic diamine compound of polyimide dissolved in a solvent such as N,N-dimethylacetamide (DMAC), any aromatic diamine compound can be used. Specifically, m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diamine group Diphenyl sulfide, 3,4'-diamino diphenyl sulfide, 4,4'-diamino diphenyl sulfide, 3,3'-diamino diphenyl sulfide, 3,4'-diphenyl sulfide Amino diphenyl sulfone, 4,4'-diamino diphenyl sulfone, 3,3'-diamino benzophenone, 3,3'-diamino diphenylmethane, 3,4' -Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl) Propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3 - Hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl)-2-(4 -aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminobenzene) oxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy) base) biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 3,4'-bis(3-aminophenoxy)biphenyl, bis[4-(4 -aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide , bis[3-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy) base) phenyl] bis[4-(4-aminophenyl) bis[3-(3-aminophenoxy)phenyl] bis[4-(3-aminophenyl) bis[4-(3-aminophenyl) ) bismuth, bis[4-(3-aminophenoxy)phenyl] ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy) base)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, bis[3-(3- Aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane , 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis [4-(3-Aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)benzene base]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3, 3-Hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,3-bis[4 -(4-Amino-6-trifluoromethylphenoxy)-α,α-di Methylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 2,2'-dimethyl base-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4, 4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, etc. These aromatic diamine compounds may be used alone, or two or more kinds of aromatic diamine compounds may be used. Furthermore, from the viewpoint of transparency, heat resistance, and solubility in a solvent, 2,2-bis(4-aminophenyl)-1,1,1,2,2-bis(4-aminophenyl)-1,1,1, 3,3,3-hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl) -2-(4-Aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1 ,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4- Aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy) -α,α-Dimethylbenzyl]benzene, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl) An aromatic diamine compound having a fluorine group such as -4,4'-diaminobiphenyl, and at least one type of the aromatic diamine compound to be used is preferably an aromatic diamine compound having a fluorine group, particularly preferably It is 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. By using an aromatic diamine compound having a fluorine group, the solubility in transparency, heat resistance, mechanical properties, and organic solvent is facilitated.

1.2. Tetracarboxylic dianhydride Also, as the tetracarboxylic dianhydride used in the production of the polyimide powder of the present invention, it is the same as the above-mentioned aromatic diamine compound, if it is given a soluble solvent (such as N, Any tetracarboxylic dianhydride of polyimide such as N-dimethylacetamide (DMAC)) can be used, and specifically, 4,4'-(1,1,1,3, 3,3-hexafluoropropane-2,2-diyl) diphthalic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 1,4-hydroquinone dibenzoate-3,3',4,4'-tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3 ',4,4'-diphenyl ether tetracarboxylic dianhydride, etc. These tetracarboxylic dianhydrides may be used alone, or two or more types of tetracarboxylic dianhydrides may be used. Furthermore, from the viewpoint of heat resistance, mechanical properties, transparency, and solubility in solvents, it is preferable to use 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2 - Tetracarboxylic dianhydride having at least one type of fluorine group, such as diphthalic dianhydride.

2. The manufacturing method of polyimide powder The polyimide powder of the present invention can use aromatic diamine compound and tetracarboxylic dianhydride as raw materials, through the polymerization of polyimide, and the imidization reaction , powdering and drying steps.

2.1. Polymerization of polyamic acid The polymerization of polyamic acid can be obtained by reacting the above-mentioned aromatic diamine compound and tetracarboxylic dianhydride by dissolving the solvent in which the polyamic acid is soluble. conduct. As the solvent used for the polymerization of p-polyamic acid, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3- Solvents for dimethyl-2-tetrahydroimidazolone, dimethyl sulfoxide, etc.

The polymerization reaction of the polyamic acid is preferably carried out while stirring in a reaction vessel equipped with a stirring device. For example, a method of dissolving a predetermined amount of an aromatic diamine compound in the above-mentioned solvent, adding tetracarboxylic dianhydride while stirring, and reacting to obtain a polyamic acid can be exemplified. The method of dissolving tetracarboxylic dianhydride in the solvent and stirring A method of obtaining a polyamic acid while adding an aromatic diamine compound and reacting, a method of alternately adding an aromatic diamine compound and a tetracarboxylic dianhydride and reacting to obtain a polyamic acid, etc.

The temperature for the polymerization reaction of the polyamic acid is not particularly limited, but it is preferably carried out at a temperature of 0 to 70°C, more preferably 10 to 60°C, and even more preferably 20 to 50°C. By carrying out the polymerization reaction within the above-mentioned range, a polyamic acid having little coloration and excellent transparency can be obtained.

In addition, although the aromatic diamine compound and tetracarboxylic dianhydride used in the polymerization of the polyamic acid are roughly used in molar amounts, in order to control the polymerization degree of the obtained polyamic acid, a specified reduction viscosity or The polyimide of the weight average molecular weight can also change the molar amount of the tetracarboxylic dianhydride/the molar amount (molar ratio) of the aromatic diamine compound within the range of 0.95 to 1.05. Furthermore, for polymerization, the reduced viscosity is 1.2 dL/g or more and less than 2.1 dL/g, the weight average molecular weight is 100,000 g/mol or more and less than 250,000 g/mol, or the reduced viscosity is 2.1 dL/g or more and 3.0 dL /g or less, or polyamide acid with a weight-average molecular weight of 250,000 g/mol or more and 500,000 g/mol or less of polyimide, the molar ratio of the tetracarboxylic acid and the aromatic diamine compound or the ratio in the solvent is well controlled. It is important to manufacture with moisture content etc. The molar ratio of the tetracarboxylic dianhydride to the aromatic diamine compound is preferably in the range of 1.001 to 1.02, more preferably 1.002 to 1.015. In this way, the degree of polymerization of the obtained polyamic acid can be stabilized by only a little excess of tetracarboxylic dianhydride, and the unit derived from tetracarboxylic dianhydride can be arranged at the end of the polymer, as a result, it becomes possible to give Polyimide with little coloration and excellent transparency.

It is preferable that the concentration of the resulting polyamic acid solution maintains the viscosity of the solution appropriately, and is adjusted to an appropriate concentration (for example, about 10 to 30 wt %) so as to facilitate the operation in the subsequent steps.

2.2. Imidization reaction The polyamic acid in the polyamic acid solution obtained below was imidized. The imidization can be performed by thermal imidization by heating a polyimide solution, or chemical imidization using an imidizing agent, or the like. In addition, from the viewpoint of the ease of control of the reduced viscosity or weight average molecular weight of the obtained polyimide, or from the viewpoint of obtaining the characteristics of the polyimide such as good heat resistance, mechanical properties, and transparency, it is preferably Imidization by chemical imidization. As the imidizing agent used in the chemical imidization reaction, carboxylic anhydrides such as acetic anhydride, propionic anhydride, succinic anhydride, phthalic anhydride, benzoic anhydride, etc. can be used, which are easy to remove from cost and after the reaction. From the viewpoint of properties, acetic anhydride is preferably used. The equivalent of the imidizing agent to be used is more than the equivalent of the amide bond of the polyamic acid for chemical imidization, preferably 1.1 to 5 times the equivalent of the amide bond, more preferably 1.5 to 4 times. As described above, the imidization reaction can be efficiently performed even at a relatively low temperature by using a small excess of the imidization agent for the imide bond.

In addition, in the chemical imidization reaction, as the imidization accelerator, aliphatic and aromatic such as pyridine, picoline, quinoline, isoquinoline, trimethylamine, and triethylamine can be used. family or heterocyclic tertiary amines. By using such amines, the imidization reaction can be carried out efficiently at a low temperature, and as a result, it becomes possible to suppress the coloration during the imidization reaction, and a more transparent polyimide can be obtained.

Although the chemical imidization reaction temperature is not particularly limited, it is preferably 10°C or higher and lower than 50°C, more preferably 15°C or higher and lower than 45°C. By carrying out the chemical imidization reaction at a temperature of 10°C or more and less than 50°C, the cleavage of the polyimide before imidization is suppressed, the control of the reduction viscosity or the weight average molecular weight is facilitated, and the polyimide is suppressed. The coloration of imine can obtain polyimide with excellent transparency.

2.3. Powderization Next, powderization of the polyimide in the polyimide solution obtained by imidization is performed. Although the powdering of polyimide can be carried out by any method, adding a poor solvent of polyimide to precipitate the polyimide and forming the powder is preferable because the method is simple. When a poor solvent is added for the precipitation and powdering of polyimide, as the poor solvent, any poor solvent that can precipitate polyimide can be used. The solvent of the so-called polyimide solution is expected to be miscible, so specifically , water, methanol, ethanol, etc. can be used. Furthermore, by using methanol as a poor solvent, it is preferable that a stable polyimide powder can be obtained in a good yield.

When performing precipitation and powdering of polyimide by a poor solvent, the amount of the poor solvent to be used must be sufficient for precipitation and powdering of polyimide, although the structure of polyimide is considered. , the solvent of the polyimide solution, the concentration of the polyimide solution, etc., but usually it is more than 0.5 times the weight of the polyimide solution used, preferably more than 0.8 times the weight of the polyimide solution, more Preferably, it is a lean solvent in a weight of 1 times or more the weight of the polyimide solution. The polyimide powder in a stable shape can be obtained in a high yield by using a lean solvent of 0.5 times or more the weight of the polyimide solution. In addition, it is usually 10 times or less the weight of the polyimide solution used, preferably 7 times or less the weight of the polyimide solution, more preferably 5 times or less the weight of the polyimide solution, and still more preferably the polyimide solution. A lean solvent with a weight of 4 times or less the weight of the imine solution.

When the powdering of the polyimide is carried out by adding a poor solvent to the polyimide solution as described above, it is preferably carried out by a method of dropping the poor solvent while stirring the polyimide solution. In order to facilitate the diffusion of the poor solvent, the polyimide solution is desirably adjusted to a concentration of preferably about 5 to 30% by weight, more preferably about 10 to 20% by weight. In addition, although the preferred average particle size of the polyimide powder obtained by the present invention is 0.02-0.8 mm, the average particle size can be controlled by the addition rate of the poor solvent to the polyimide solution.

In the present invention, the temperature for powdering polyimide is not particularly limited, but when precipitation and powdering are performed by adding a poor solvent, the evaporation of the poor solvent is suppressed and the precipitation is efficiently performed. See, it is preferable to carry out at the temperature of 50 degrees C or less, and it is more preferable to carry out at 40 degrees C or less.

2.4. Drying The polyimide powder obtained below is dried to remove the solvent, imidization agent, imidization accelerator, poor solvent, etc. The drying system removes the above-mentioned polyimide solvent, imidization agent, and imidization accelerator in advance by filtering the polyimide powder through a filter device in advance, and then washing it if necessary. It is preferable to carry out the drying later, in view of efficient drying.

The drying of the above-mentioned polyimide powder can be carried out at any temperature if it can remove the residues of the polyimide solvent, imidization agent, imidization accelerator, poor solvent, etc. When a poor solvent having hydroxyl groups such as methanol and ethanol is used as the above-mentioned poor solvent, and immediately drying at a temperature of 100°C or higher, the carboxylic acid group or carboxylic acid anhydride group in the polyimide reacts with the above-mentioned poor solvent, resulting in the formation of The ester bond may cause a decrease in heat resistance, and coloration may further introduce the problem of a decrease in molecular weight. Accordingly, the drying step is preferably performed in two stages or more from a temperature below 100°C and a temperature from 100 to 350°C, or from a temperature below 100°C to a temperature from 100°C to 350°C. In addition, the drying of the polyimide powder can be performed under normal pressure, and there is no problem even if it is performed under reduced pressure.

3. Polyimide Powder The polyimide powder of the first embodiment of the present invention can be obtained by mixing the polyimide powder A and the polyimide powder B in a weight ratio. Mix the polyimide powder A/polyimide powder B=10/90 to 90/10, and adjust the reduced viscosity measured for the resulting mixture to 1.7 to 2.5 dL/g, preferably 1.8～2.4dL/g, more preferably 1.9～2.3dL/g, particularly preferably 2.0～2.2dL/g, or the weight average molecular weight measured for the obtained mixture is adjusted to 160,000～350,000g/mol, preferably 200,000-330,000 g/mol, more preferably 220,000-310,000 g/mol, particularly preferably 240,000-290,000 g/mol, and the polyimide powder A is obtained by the above-mentioned method (a- 1) Polyimide with reduced viscosity of 1.2dL/g or more and less than 2.1dL/g, preferably 1.4dL/g or more and less than 2.1dL/g, or (a-2) Weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol, preferably 150,000 g/mol or more and less than 250,000 g/mol of polyimide, the polyimide powder B is composed of (b-1) Polyimide with reduced viscosity of 2.1dL/g or more and 3.0dL/g or less, preferably 2.1dL/g or more and 2.8dL/g or less, or (b-2) weight average molecular weight of 250,000g/mol or more and 500,000g /mol or less, preferably 250,000 g/mol or more and 400,000 g/mol or less of polyimide.

For the mixing of the polyimide powder, for example, the method of using a rotary mixer, the method of using a horizontal stirring mixer, the method of using a vertical stirring mixer, etc., can be used to uniformly mix the polyimide powder A. It is carried out by any method with polyimide powder B.

4. Polyimide coating The polyimide coating of the second embodiment of the present invention can be prepared by mixing the polyimide powder in any organic solvent soluble in polyimide at a concentration of 1 to 30 wt %. The polyimide powder system is obtained by dissolving the above-mentioned polyimide powder A and polyimide powder B at a specified weight ratio, and the reduced viscosity of the first embodiment is 1.7～ 2.5dL/g, or a weight average molecular weight of 160,000 to 350,000 g/mol.

In addition, the polyimide coating of the present invention can also be mixed in an organic solvent with 1 to 30% by weight of the polyimide powder A and the polyimide powder B in the powder state. After the concentration is dissolved as the polyimide solution, the weight ratio of the polyimide A and the polyimide B as the solute is in the range of 10/90 to 90/10, and the individual polyimide solutions are mixed to become the polyimide solution. The purpose of the polyimide coating.

5. Polyimide Properties (1 Powder Properties) The reduction viscosity of the polyimide constituting the polyimide powder A before mixing is 1.2 dL/g or more and less than 2.1 dL/g, which constitutes the polyimide The reducing viscosity of the polyimide of the imine powder B is 2.1 dL/g or more and 3.0 dL/g or less. For the first implementation of the present invention after mixing the polyimide powder A and the polyimide powder B The measured reducing viscosity of the polyimide powder of this embodiment is 1.7-2.5dL/g, preferably 1.8-2.4dL/g, more preferably 1.9-2.3dL/g, particularly preferably 2.0-2.2dL/g g. When the reduced viscosity measured for the polyimide powder is less than 1.7 dL/g, the mechanical properties such as the tensile strength, elongation, and bending resistance of the finally obtained polyimide film are impaired, and the polyimide The hygroscopicity may increase, and when the reduced viscosity exceeds 2.5 dL/g, the viscosity of the polyimide solution is too high, resulting in a problem that handling becomes difficult.

Furthermore, in the present invention, by mixing the polyimide powder A composed of the polyimide with a low reduction viscosity and the polyimide powder B composed of the polyimide with a high reduction viscosity, the The control of the reduced viscosity of the mixed polyimide becomes easier, and the mechanical properties of the obtained polyimide film are better than those obtained from the unmixed polyimide powder. The advantage of the tendency to have more excellent mechanical properties.

Or the weight average molecular weight of the polyimide constituting the polyimide powder A before mixing is 100,000 g/mol or more and less than 250,000 g/mol, and the weight of the polyimide constituting the polyimide powder B The average molecular weight is 250,000 g/mol or more and 500,000 g/mol or less, measured on the polyimide powder of the first embodiment of the present invention after mixing the polyimide powder A and the polyimide powder B The weight average molecular weight is 160,000-350,000 g/mol, preferably 200,000-330,000 g/mol, more preferably 220,000-310,000 g/mol, particularly preferably 240,000-290,000 g/mol. When the weight-average molecular weight measured for the polyimide powder is less than 160,000 g/mol, the mechanical properties such as tensile strength, elongation, and bending resistance of the final polyimide film are impaired, and the polyimide film is not suitable for polyimide. There is a possibility that the moisture absorption of the amine may increase, and when the weight average molecular weight exceeds 350,000 g/mol, the viscosity of the polyimide solution is too high, and there is a problem that handling becomes difficult.

Moreover, in the present invention, by mixing the polyimide powder A composed of the low weight average molecular weight polyimide and the polyimide powder B composed of the high weight average molecular weight polyimide , it is easy to control the weight average molecular weight exhibited by the mixed polyimide, and the mechanical properties of the obtained polyimide film are better than those obtained from the unmixed polyimide powder. It is an advantage of the tendency that the mechanical properties of the amine film are more excellent.

Moreover, the average particle diameter of the polyimide powder is preferably 0.02 to 0.8 mm, more preferably 0.03 to 0.6 mm. If the average particle size is in the range of 0.02 to 0.8 mm, residual volatile components such as solvent, poor solvent, imidizing agent, etc. in the polyimide powder can be efficiently removed, and it is easy to obtain a product with very little coloration and excellent transparency. Polyimide.

The average particle size of the polyimide powder of the present invention can be measured by a laser diffraction/scattering particle size distribution analyzer.

7. Polyimide Properties (2 Coating Properties) In the polyimide coating of the second embodiment of the present invention, the polyimide powder A and the polyimide powder B can be mixed with polyimide. The weight ratio of powder A/polyimide powder B is mixed in the range of 10/90 to 90/10, that is, the polyimide powder, which is the first embodiment of the present invention, is 1 to 30 by weight. The polyimide powder A is obtained by dissolving it in an organic solvent so that the concentration of Powder B is composed of polyimide having a reduced viscosity of not less than 2.1 dL/g and not more than 3.0 dL/g.

Or in the polyimide coating of the second embodiment of the present invention, the polyimide powder A and the polyimide powder B can be mixed with the polyimide powder A/polyimide powder B. The polyimide powder, which is the first embodiment of the present invention obtained by mixing the weight ratio in the range of 10/90 to 90/10, is obtained by dissolving it in an organic solvent so as to have a concentration of 1 to 30 parts by weight, The polyimide powder A is composed of polyimide with a weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol, and the polyimide powder B is composed of a weight average molecular weight of 250,000 g /mol or more and 500,000 g/mol or less of polyimide.

In addition, the polyimide paint of the present invention may be a paint in which the polyimide powder A is dissolved in an organic solvent at a concentration of 1 to 30% by weight, and the polyimide powder B may be 1 The paint is dissolved in an organic solvent at a concentration of ~30% by weight, and the weight ratio of the polyimide powder A and the polyimide powder B in solution is A/B=10/90～90/10 obtained by mixing.

The organic solvent used in the polyimide coating of the present invention can be any solvent if it can dissolve the polyimide powder, and N,N-dimethylacetamide, N , N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, 2-butanone, acetonitrile, etc. In addition, the organic solvent used in the polyimide paint of the present invention can be used alone, or it can be mixed with two or more kinds of solvents. The body is fine. Moreover, as long as solubility can be maintained, even if it contains components other than organic solvents, such as water, it does not matter.

8. Polyimide properties (3 film properties) For the transparency of the polyimide powder or polyimide coating of the present invention, the polyimide powder can be dissolved in N, After using N-dimethylacetamide (DMAC) as a polyimide coating, a film formed by a casting method so as to have a thickness of 50 μm after drying was used, and the total light transmission measured by a spectrocolorimeter was used. rate and obtained by yellowness. Furthermore, the total light transmittance of the polyimide film obtained from the polyimide powder or polyimide coating of the present invention is preferably 85% or more, more preferably 90% or more. Moreover, it is preferable that it is -3 to 3, it is more preferable that it is -2 to 2, and it is still more preferable that it is -1.5 to 1.5 with respect to yellowness. When the total light transmittance is less than the above lower limit, or when the yellowness is outside the above range, it may be difficult to provide a film having excellent transparency for use in optical applications such as displays. Moreover, the imidization rate of the polyimide constituting the polyimide powder of the present invention is preferably 90% or more, more preferably 95% or more. The imidization rate can be determined by Fourier transform infrared spectroscopy (FT-IR method) of the polyimide film obtained by the above method. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

(Method for measuring the reduction viscosity of polyimide) A polyimide solution was prepared by dissolving polyimide powder in N,N-dimethylacetamide (DMAC) so as to have a concentration of 0.5 g/dL . Using an Ubbelohde viscometer, the outflow time (T) of the polyimide solution at a temperature of 30° C. and the outflow time (T0) of the DMAC alone as the solvent were measured, and the reduced viscosity was obtained by the following formula. Reduced viscosity (dL/g)=(T-T0)/T0/0.5

(Measurement method of weight average molecular weight of polyimide) Prepare a tetrahydrofuran solution of polyimide with a concentration of 1 mg/mL, and use a size exclusion chromatography apparatus (HLC-8320GPC manufactured by Tosoh Corporation) to elute: Measured under the conditions of tetrahydrofuran (stabilizer-free), column: TSKgel SuperHM-M (two tubes in-line), detector: differential refractometer, measurement temperature: 40°C, flow rate: 0.6 mL/min, injection volume: 40 μL. The molecular weight was calculated as a relative molecular weight value converted from a standard substance (standard substance: standard polystyrene 12 points (molecular weight 504 to 1,090,000), calibration curve: a cubic approximation curve).

(Measuring Method of Average Particle Size of Polyimide Powder) Using a laser diffraction/scattering particle size distribution analyzer (LA-950V2 manufactured by Horiba Seisakusho Co., Ltd.), it was measured using ethanol as a dispersing medium.

(Measuring method of total light transmittance and yellowness of polyimide) (1) Preparation method of film sample for measurement Polyimide powder was made into the amount specified in the following Examples or Comparative Examples. Dissolved in N,N-dimethylacetamide. Next, using an applicator, a film was formed on a smooth glass plate so as to have a thickness of 50 μm after drying, and the temperature was increased at 5°C/min from 130°C to 260°C after holding it in a hot air oven at 130°C for 60 minutes. , and further dried at 260° C. for 10 minutes, then taken out from the hot air oven, cooled to room temperature, and peeled off from the glass plate as a polyimide film sample for measurement.

(2) Measurement of total light transmittance Using a spectrocolorimeter (manufactured by Konica Minolta Co., Ltd., CM-5), according to ASTM E 1164, under the conditions of light source C and viewing angle of 2°, when the film thickness is 50 μm the total light transmittance.

(3) Measurement of yellowness (YI) Using a spectrocolorimeter (manufactured by Konica Minolta Co., Ltd., CM-5), according to ASTM D 1925, under the conditions of light source C and viewing angle of 2°, at 360 to 740 nm The wavelength range was scanned, and the yellowness (YI) at a film thickness of 50 μm was obtained.

(Measuring method of tensile strength and elongation of polyimide film) By the same method as the manufacturing method of the polyimide film used in the measurement of the total light transmittance and yellowness of polyimide, to The polyimide film was prepared in such a way that the polyimide film did not have the disadvantage that foreign matter, air bubbles, etc. would not enter. Next, the obtained polyimide film was cut into a size of 10 mm×150 mm using a feather blade, and 10 test pieces were prepared. The obtained test piece was subjected to a tensile test using a tensile tester (Autograph AGS-X load cell 500N manufactured by Shimadzu Corporation) at a distance between the chucks of 50 mm and a tensile speed of 50 mm/min, and the time of breaking was measured. For the tensile strength and elongation, the average value of 10 tests was obtained as the individual tensile strength and elongation.

(Example X1) 461 g of solvent N,N-dimethylacetamide (DMAC) (containing 100 ppm of water. Hereinafter, in all Example X and Comparative Example X used the same DMAC) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), an aromatic diamine compound having a fluorine group. ) 64.047 g (0.2000 moles) were stirred to dissolve TFMB in DMAC. Next, while stirring the inside of the separable flask, under nitrogen flow, tetracarboxylic dianhydride 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl) Diphthalic acid dianhydride (6FDA) 89.737 g (0.2020 mol) was divided into about 10 minutes, and the polymerization reaction was carried out while continuously stirring for 6 hours while adjusting the temperature so that the temperature was in the temperature range of 20 to 40°C. A viscous polyamide solution was obtained. The molar ratio of the used tetracarboxylic dianhydride/aromatic diamine compound was 1.01, and the concentration of the polyamic acid solution was 25% by weight.

410 g of DMAC was added to the obtained polyamic acid solution, and after diluting so that the concentration of polyamic acid became 15% by weight, 25.83 g of isoquinoline was added as an imidization accelerator, and the polyamic acid solution was stirred while stirring. Maintained at a temperature range of 30 to 40°C, as an imidizing agent, 122.5 g (1.20 mol) of acetic anhydride was slowly added dropwise to it for about 10 minutes, and then the liquid temperature was maintained at 30 to 40 °C. The stirring was continued at °C for 12 hours, and the chemical imidization reaction was carried out to obtain a polyimide solution.

Next, 1,000 g of a polyimide solution containing the obtained imidization agent and imidization accelerator was transferred to a 5-L separable flask equipped with a stirring device and a stirring blade, and kept at 120 rpm while being stirred at a speed of 120 rpm. At a temperature of 15 to 25°C, 1500 g of methanol was dropped thereon at a rate of 10 g/min. When about 800 g of methanol was put in, the turbidity of the polyimide solution was confirmed, and the precipitation of powdery polyimide was confirmed. Next, 1500 g of methanol in total was put in to complete the precipitation of polyimide.

Next, the contents of the separable flask were filtered off by a suction filtration device, and further washed and filtered using 1000 g of methanol.

Then, 50 g of the filtered polyimide powder was dried at 50° C. for 24 hours using a dryer equipped with a local exhaust device, and further dried at 260° C. for 2 hours to remove residual volatile components to obtain polyimide. Imine powder (a-1). The reduced viscosity measured for the polyimide powder (a-1) was 1.52 dL/g.

Next, similarly to the polyimide powder (a-1), 460 g of DMAC and 64.047 g (0.200 mol) of TFMB were put into a 2 L separable flask and stirred to dissolve TFMB in DMAC. Next, 6FDA89.204 g (0.2008 mol) was poured into the separable flask while stirring the inside of the separable flask under nitrogen flow for about 10 minutes, and the stirring was continued for 6 hours while adjusting the temperature to be in the temperature range of 20 to 40°C. A polymerization reaction was carried out to obtain a viscous polyamide solution. The molar ratio of the used tetracarboxylic dianhydride/aromatic diamine compound was 1.004, and the concentration of the polyamic acid solution was 25% by weight.

Then, chemical imidization, powderization, and drying were carried out in the same manner as the polyimide powder (a-1) to obtain a polyimide powder composed of polyimide having a reduced viscosity of 2.54 dL/g. body (b-1).

20 g of the obtained polyimide powder (a-1) and 20 g of the polyimide powder (b-1) were placed in a rotary mixer for more than 1 hour and fully mixed to obtain the intended polyimide imine powder. The reduced viscosity measured for the obtained polyimide powder was 2.03 dL/g, and the average particle size was 0.06 mm.

Next, mix the polyimide powder (a-1) and the polyimide powder (b-1), and dissolve 20 g of the obtained polyimide powder in 80 g of DMAC to obtain a uniform polyimide solution Then, using an applicator, a film was applied to a glass plate, and DMAC was dried under predetermined conditions, and then peeled off from the glass plate to prepare a polyimide film having a thickness of 50 μm. The total light transmittance of the obtained polyimide film was as high as 90%, the yellowness was 1.3, the discoloration was not observed even by visual observation, and the transparency was extremely excellent. In addition, as a result of the tensile test of the polyimide film, it was excellent in a tensile strength of 160 MPa and an elongation of 70%.

(Example X2) In addition to using 16 g of polyimide powder (a-1) composed of polyimide having a reduced viscosity of 1.52 dL/g obtained in Example X1, the reduced viscosity of 2.54 dL/g was used. 24 g of polyimide powder (b-1) composed of The weight ratio was carried out in the same manner as in Example X1 except that the polyimide powder (a-1)/polyimide powder (b-1)=40/60.

The reduced viscosity measured for the obtained polyimide powder was 2.13 dL/g, and the average particle size was 0.06 mm. Moreover, the total light transmittance of the 50-μm-thick polyimide film obtained from the polyimide powder was as high as 90%, the yellowness was 1.3, and the transparency was extremely excellent. In addition, the tensile strength of the polyimide film was 165 MPa. An elongation of 72% was considered excellent.

(Example X3) In addition to using 14 g of polyimide powder (a-1) composed of polyimide having a reduced viscosity of 1.52 dL/g obtained in Example X1, a reduced viscosity of 2.54 dL/g was used. 26g of polyimide powder (b-1) composed of The weight ratio was carried out in the same manner as in Example X1 except that the weight ratio was polyimide powder (a-1)/polyimide powder (b-1)=35/65.

The reduced viscosity measured for the obtained polyimide powder was 2.18 dL/g, and the average particle size was 0.06 mm. Moreover, the total light transmittance of the 50-μm-thick polyimide film obtained from the polyimide powder was as high as 91%, the yellowness was 1.3, and the transparency was extremely excellent. In addition, the tensile strength of the polyimide film was 160 MPa. An elongation of 70% was considered excellent.

(Example X4) Except that the usage amount of 6FDA used in the synthesis of the polyimide powder (a-1) was not 89.737g (0.2020 mol), but 89.559 g (0.2016 mol), The polyimide powder (a-1) was synthesized in the same manner as in Example X1 except that the molar ratio of the tetracarboxylic dianhydride/aromatic diamine compound was set to 1.008, and the reduced viscosity was 1.83. Polyimide powder (a-1) composed of dL/g of polyimide.

Next, 30 g of the obtained polyimide powder (a-1) with a reduced viscosity of 1.83 dL/g and 10 g of the polyimide powder (b-1) with a reduced viscosity of 2.54 dL/g obtained in Example X1 , it takes more than 1 hour to fully mix in the mixing device of the rotary type, and the weight ratio of polyimide powder (a-1)/polyimide powder (b-1) is 75/25. imine powder.

The reduced viscosity measured for the obtained polyimide powder was 2.01 dL/g, and the average particle size was 0.08 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 91%, a yellowness of 1.3, no discoloration was observed even by visual observation, and it was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 155 MPa, and the elongation was 65%.

(Example X5) Except that the usage amount of 6FDA used in the synthesis of the polyimide powder (b-1) was not 89.204g (0.2008 mol), but 89.293 g (0.2010 mol), The polyimide powder (b-1) was synthesized in the same manner as in Example X1 except that the molar ratio of the tetracarboxylic dianhydride/aromatic diamine compound was set to 1.005, and the reduced viscosity was 2.26. Polyimide powder (b-1) composed of dL/g polyimide.

Next, 10 g of the polyimide powder (a-1) with a reduced viscosity of 1.52 dL/g obtained in Example X1 and the polyimide powder (b-1) with a reduced viscosity of 2.26 dL/g obtained in this example were combined. 30g, put it into the mixing device of the rotary type and spend more than 1 hour to mix thoroughly to obtain a polyimide powder (a-1)/polyimide powder (b-1) with a weight ratio of 25/75. Imide powder.

The reduced viscosity measured for the obtained polyimide powder was 2.08 dL/g, and the average particle size was 0.09 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 90%, a yellowness of 1.3, and no discoloration was observed even by visual inspection, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 158 MPa, and the elongation was 68%.

(Example X6) Except that the amount of DMAC used in the synthesis of the polyimide powder (a-1) was not 461 g but 485 g, as the aromatic diamine compound, 64.047 g (0.2000 g (0.2000 g) TFMB was replaced mol), use TFMB51.238g (0.1600 mol) and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane (BAPP-F) 20.738g (0.0400mol), the amount of DMAC used for dilution before the chemical imidization reaction was not set at 410g but set at 431g, the other was carried out in the same way as in Example X1 Synthesis of polyimide powder (a-1), as an aromatic diamine compound, obtains TFMB and BAPP-F, and as a tetracarboxylic dianhydride, obtains a compound with a reduced viscosity of 1.59 dL/g synthesized by 6FDA Polyimide powder (a-1) composed of polyimide.

20 g of the obtained polyimide powder (a-1) with a reduced viscosity of 1.59 dL/g and 20 g of the polyimide powder (b-1) with a reduced viscosity of 2.54 dL/g obtained in Example X1 were put into It takes more than 1 hour to fully mix in the mixing device of the rotary type, and the weight ratio of the polyimide powder (a-1)/polyimide powder (b-1) is 50/50 to obtain the polyimide powder.

The reduced viscosity measured for the obtained polyimide powder was 2.07 dL/g, and the average particle size was 0.10 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 89%, a yellowness of 1.4, and no discoloration was observed even by visual observation, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 150 MPa, and the elongation was 60%.

(Example X7) A polyimide coating A and a polyimide coating B were prepared. The polyimide coating A was the polyimide powder with a reduced viscosity of 1.52 dL/g obtained in Example X1 (a -1) 20 g is dissolved in 80 g of DMAC, the polyimide coating B is to dissolve 20 g of the polyimide powder (b-1) with a reduced viscosity of 2.54 dL/g obtained in Example X1 in 80 g of DMAC, Mixing polyimide coating A50g (polyimide powder (a-1) 10g dissolved solute) and polyimide coating B50g (polyimide powder (b-1) 10g dissolved solute), and The intended polyimide paint was obtained.

The obtained polyimide coating was determined to have a concentration of 0.5 g/dL, and the measured reduced viscosity was 2.03 dL/g.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 90%, a yellowness of 1.3, and no discoloration was observed even by visual inspection, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 165 MPa, and the elongation was 70%.

(Comparative Example X1) Only 20 g of the polyimide powder (a-1) with a reduced viscosity of 1.52 dL/g synthesized in Example X1 was dissolved in 80 g of DMAC to obtain a uniform polyimide solution, and then used When the applicator coats the film on the glass plate, after drying DMAC under the specified conditions, the polyimide film with a thickness of 50 μm is peeled off from the glass plate, and the total light transmittance of the obtained polyimide film is 89%, yellow Degree of 1.8, tensile strength of 125MPa, and elongation as low as 20%.

(Comparative Example X2) Only when 20 g of the polyimide powder (b-1) with a reduced viscosity of 2.54 dL/g synthesized in Example X1 was dissolved in 80 g of DMAC, the viscosity of the polyimide coating was too high, making it difficult to A paint suitable for the viscosity of the coating film. Therefore, after further adding 60 g of DMAC as a 12.5% coating material, the film was coated on a glass plate using an applicator, and after drying DMAC under the specified conditions, it was peeled off from the glass plate to prepare a polyimide film with a thickness of 50 μm. Although the total light transmittance of the obtained polyimide film was 90% and the yellowness was 1.3, the tensile strength was 145 MPa and the elongation was 40%, which was lower than that of Example X above.

The results are gathered in Table 1.

(Example Y1) Into a 2L separable flask made of glass equipped with a stirring device and a stirring blade, put 461 g of solvent N,N-dimethylacetamide (DMAC) (containing 100 ppm of water. Hereinafter, in all Example Y and Comparative Example Y used the same DMAC) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), an aromatic diamine compound having a fluorine group. ) 64.047 g (0.2000 moles) were stirred to dissolve TFMB in DMAC. Next, while stirring the inside of the separable flask, under nitrogen flow, tetracarboxylic dianhydride 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl) Diphthalic acid dianhydride (6FDA) 89.737 g (0.2020 mol) was divided into about 10 minutes, and the polymerization reaction was carried out while continuously stirring for 6 hours while adjusting the temperature so that the temperature was in the temperature range of 20 to 40°C. A viscous polyamide solution was obtained. The molar ratio of the used tetracarboxylic dianhydride/aromatic diamine compound was 1.01, and the concentration of the polyamic acid solution was 25% by weight.

410 g of DMAC was added to the obtained polyamic acid solution, and after diluting so that the concentration of polyamic acid became 15% by weight, 25.83 g of isoquinoline was added as an imidization accelerator, and the polyamic acid solution was stirred while stirring. It was kept in a temperature range of 30 to 40°C, and as an imidizing agent, 122.5 g (1.20 mol) of acetic anhydride was slowly added dropwise to it for about 10 minutes, and then the liquid temperature was kept at 30 to 40 The stirring was continued at °C for 12 hours, and the chemical imidization reaction was carried out to obtain a polyimide solution.

Next, 1,000 g of a polyimide solution containing the obtained imidization agent and imidization accelerator was transferred to a 5-L separable flask equipped with a stirring device and a stirring blade, and kept at 120 rpm while being stirred at a speed of 120 rpm. At a temperature of 15 to 25°C, 1500 g of methanol was dropped thereon at a rate of 10 g/min. When about 800 g of methanol was put in, the turbidity of the polyimide solution was confirmed, and the precipitation of powdery polyimide was confirmed. Next, 1500 g of methanol in total was put in to complete the precipitation of polyimide.

Next, the contents of the separable flask were filtered off by a suction filtration device, and further washed and filtered using 1000 g of methanol.

Then, 50 g of the filtered polyimide powder was dried at 50° C. for 24 hours using a dryer equipped with a local exhaust device, and further dried at 260° C. for 2 hours to remove residual volatile components to obtain polyimide. Imine powder (a-2). The weight average molecular weight measured for the polyimide powder (a-2) was 195,000 g/mol.

Next, similarly to the polyimide powder (a-2), 460 g of DMAC and 64.047 g (0.200 mol) of TFMB were put into a 2 L separable flask and stirred to dissolve TFMB in DMAC. Next, 6FDA89.204 g (0.2008 mol) was poured into the separable flask while stirring the inside of the separable flask under nitrogen flow for about 10 minutes, and the stirring was continued for 6 hours while adjusting the temperature to be in the temperature range of 20 to 40°C. A polymerization reaction was carried out to obtain a viscous polyamide solution. The molar ratio of the used tetracarboxylic dianhydride/aromatic diamine compound was 1.004, and the concentration of the polyamic acid solution was 25% by weight.

Then, chemical imidization, powderization, and drying were carried out in the same manner as the polyimide powder (a-2) to obtain a polyimide composed of polyimide having a weight average molecular weight of 342,000 g/mol. Powder (b-2).

20 g of the obtained polyimide powder (a-2) and 20 g of the polyimide powder (b-2) were placed in a rotary mixer for more than 1 hour and fully mixed to obtain the intended polyimide imine powder. The weight average molecular weight measured for the obtained polyimide powder was 259,000 g/mol, and the average particle diameter was 0.06 mm.

Next, mix the polyimide powder (a-2) and the polyimide powder (b-2), and dissolve 20 g of the obtained polyimide powder in 80 g of DMAC to obtain a uniform polyimide solution Then, using an applicator, a film was applied to a glass plate, and DMAC was dried under predetermined conditions, and then peeled off from the glass plate to prepare a polyimide film having a thickness of 50 μm. The total light transmittance of the obtained polyimide film was as high as 90%, the yellowness was 1.3, the discoloration was not observed even by visual observation, and the transparency was extremely excellent. In addition, as a result of the tensile test of the polyimide film, a tensile strength of 160 MPa and an elongation of 70% were excellent.

(Example Y2) In addition to using 16 g of polyimide powder (a-2) composed of polyimide having a weight-average molecular weight of 195,000 g/mol obtained in Example Y1, a weight-average molecular weight of 342,000 g was used. 24 g of polyimide powder (b-2) composed of polyimide/mol, the mixing ratio of polyimide powder (a-2) and polyimide powder (b-2) , except that the weight ratio became polyimide powder (a-2)/polyimide powder (b-2)=40/60, the same procedure as in Example Y1 was carried out.

The weight average molecular weight measured for the obtained polyimide powder was 269,000 g/mol, and the average particle diameter was 0.06 mm. Moreover, the total light transmittance of the 50-μm-thick polyimide film obtained from the polyimide powder was as high as 90%, the yellowness was 1.3, and the transparency was extremely excellent. In addition, the tensile strength of the polyimide film was 165 MPa. Excellent elongation of 72%.

(Example Y3) In addition to using 14 g of the polyimide powder (a-2) composed of the polyimide having a weight average molecular weight of 195,000 g/mol obtained in Example Y1, a weight average molecular weight of 342,000 g was used. 26 g of polyimide powder (b-2) composed of polyimide/mol, the mixing ratio of polyimide powder (a-2) and polyimide powder (b-2) , except that the weight ratio is polyimide powder (a-2)/polyimide powder (b-2)=35/65, the same procedure as in Example Y1 was carried out.

The weight average molecular weight measured for the obtained polyimide powder was 280,000 g/mol, and the average particle diameter was 0.06 mm. Moreover, the total light transmittance of the 50-μm-thick polyimide film obtained from the polyimide powder was as high as 91%, the yellowness was 1.3, and the transparency was extremely excellent. In addition, the tensile strength of the polyimide film was 160 MPa. The elongation is excellent at 70%.

(Example Y4) Except that the usage amount of 6FDA used in the synthesis of the polyimide powder (a-2) is not 89.737g (0.2020 mol), but 89.559 g (0.2016 mol), The polyimide powder (a-2) was synthesized in the same manner as in Example Y1, except that the molar ratio of the tetracarboxylic dianhydride/aromatic diamine compound was set to 1.008, and the weight average molecular weight was Polyimide powder (a-2) composed of 210,000 g/mol of polyimide.

Next, 30 g of the obtained polyimide powder (a-2) with a weight average molecular weight of 210,000 g/mol and the polyimide powder (b-2) with a weight average molecular weight of 342,000 g/mol obtained in Example Y1 were combined. ) 10g, put it into the mixing device of the rotary type and spend more than 1 hour to mix thoroughly, and the weight ratio of the obtained polyimide powder (a-2)/polyimide powder (b-2) is 75/25. Polyimide powder.

The weight average molecular weight measured for the obtained polyimide powder was 255,000 g/mol, and the average particle diameter was 0.08 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 91%, a yellowness of 1.3, no discoloration was observed even by visual observation, and it was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 155 MPa, and the elongation was 65%.

(Example Y5) Except that the usage amount of 6FDA used in the synthesis of the polyimide powder (b-2) is not 89.204g (0.2008 mol), but 89.293 g (0.2010 mol), The polyimide powder (b-2) was synthesized in the same manner as in Example Y1 except that the molar ratio of the tetracarboxylic dianhydride/aromatic diamine compound was set to 1.005, and the result was obtained with a weight-average molecular weight of Polyimide powder (b-2) composed of 292,000 g/mol of polyimide.

Next, 10 g of the polyimide powder (a-2) with a weight average molecular weight of 195,000 g/mol obtained in Example Y1 and the polyimide powder (b) with a weight average molecular weight of 292,000 g/mol obtained in this example -2) 30g, put it into a rotary type mixing device and spend more than 1 hour to mix thoroughly, and the weight ratio of the obtained polyimide powder (a-2)/polyimide powder (b-2) is 25/ 75 of polyimide powder.

The weight average molecular weight measured for the obtained polyimide powder was 268,000 g/mol, and the average particle diameter was 0.09 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 90%, a yellowness of 1.3, and no discoloration was observed even by visual inspection, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 158 MPa, and the elongation was 68%.

(Example Y6) Except that the amount of DMAC used in the synthesis of the polyimide powder (a-2) was not 461 g but 485 g, as an aromatic diamine compound, substituted TFMB64.047 g (0.2000 g) mol), use TFMB51.238g (0.1600 mol) and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoro Propane (BAPP-F) 20.738g (0.0400mol), the amount of DMAC used for dilution before the chemical imidization reaction was not set at 410g but set at 431g, the other was carried out in the same way as in Example Y1 Synthesis of polyimide powder (a-2), as aromatic diamine compound, obtained TFMB and BAPP-F, and as tetracarboxylic dianhydride, obtained by using 6FDA synthesis weight average molecular weight of 205,000g/ Polyimide powder (a-2) composed of mol of polyimide.

20 g of the obtained polyimide powder (a-2) with a weight average molecular weight of 205,000 g/mol and the polyimide powder (b-2) with a weight average molecular weight of 342,000 g/mol obtained in Example Y1 20g, put it into the mixing device of the rotary type and spend more than 1 hour to mix thoroughly, and obtain the polyimide powder (a-2)/polyimide powder (b-2) with a weight ratio of 50/50. Imide powder.

The weight average molecular weight measured for the obtained polyimide powder was 261,000 g/mol, and the average particle diameter was 0.10 mm.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example X1 had a high total light transmittance of 89%, a yellowness of 1.4, and no discoloration was observed even by visual observation, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 150 MPa, and the elongation was 60%.

(Example Y7) A polyimide coating A and a polyimide coating B were prepared. The polyimide coating A is a polyimide powder with a weight-average molecular weight of 195,000 g/mol obtained in Example Y1 ( a-2) 20g is dissolved in 80g of DMAC, the polyimide coating B is to dissolve 20g of the polyimide powder with a weight average molecular weight of 342,000g/mol obtained in Example Y1 (b-2) in 80g DMAC, mixed polyimide coating A50g (polyimide powder (a-2) 10g dissolved solute) and polyimide coating B50g (polyimide powder (b-2) 10g dissolved solute) ) to obtain the intended polyimide coating.

The weight average molecular weight of the polyimide dissolved in the obtained polyimide coating material was 259,000 g/mol.

Hereinafter, the polyimide film with a thickness of 50 μm produced in the same manner as in Example Y1 had a high total light transmittance of 90%, a yellowness of 1.3, and no discoloration was observed even by visual observation, which was extremely excellent in transparency. In addition, the tensile strength of the polyimide film was 165 MPa, and the elongation was 70%.

(Comparative Example Y1) Only after dissolving 20 g of the polyimide powder (a-2) with a weight average molecular weight of 195,000 g/mol synthesized in Example Y1 in 80 g of DMAC to obtain a uniform polyimide solution, After coating the film on a glass plate with an applicator, drying DMAC under the specified conditions, and peeling off the glass plate to make a polyimide film with a thickness of 50 μm, the total light transmittance of the obtained polyimide film is 89%. The yellowness was 1.8, the tensile strength was 125 MPa, and the elongation was as low as 20%.

(Comparative Example Y2) Only when 20 g of polyimide powder (b-2) with a weight average molecular weight of 342,000 g/mol synthesized in Example Y1 was dissolved in 80 g of DMAC, the viscosity of the polyimide coating was too high, It is difficult to make a coating suitable for the viscosity of the coating film. Therefore, after further adding 60 g of DMAC as a 12.5% coating material, the film was coated on a glass plate using an applicator, and after drying DMAC under the specified conditions, it was peeled off from the glass plate to prepare a polyimide film with a thickness of 50 μm. Although the total light transmittance of the obtained polyimide film was 90% and the yellowness was 1.3, when the tensile strength was 145 MPa and the elongation was 40%, compared with the above-mentioned Example Y, the results were lower.

[產業上之可利用性]The results are gathered in Table 2.

[Industrial Availability]

If the polyimide powder or polyimide coating according to the present invention is used, it is possible to manufacture polyimide having excellent heat resistance, mechanical properties and transparency, especially suitable for use in displays or electronic materials. The imine film has extremely high industrial value.

Claims (11)

A polyimide powder, which is composed of a mixture of polyimide powder A and polyimide powder B, and is a polyimide powder soluble in organic solvents, characterized by a polyimide powder. Imide powder A and polyimide powder B, each composed of a polyimide having a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride Consists of amines, at least one kind of aromatic diamine compound, including at least one kind of aromatic diamine compound having a fluorine group, and at least one kind of tetracarboxylic dianhydride, including at least one kind of fluorine group. Aromatic tetracarboxylic dianhydride, polyimide powder A is composed of polyimide having a reducing viscosity of (a-1) 1.2dL/g or more and less than 2.1dL/g, polyimide Powder B is composed of (b-1) polyimide having a reducing viscosity of not less than 2.1 dL/g and not more than 3.0 dL/g, and the weight of the aforementioned polyimide powder A/polyimide powder B The ratio is in the range of 10/90 to 90/10, and the reduced viscosity measured for the mixture of the polyimide powder A and the polyimide powder B is in the range of 1.7 to 2.5 dL/g. A polyimide powder, which is composed of a mixture of polyimide powder A and polyimide powder B, and is a polyimide powder soluble in organic solvents, characterized by a polyimide powder. Imide powder A and polyimide powder B, respectively Consisting of a polyimide having a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride, in the at least one type of aromatic diamine compound, Contains at least one kind of aromatic diamine compound having fluorine group, at least one kind of tetracarboxylic dianhydride described above, contains at least one kind of aromatic tetracarboxylic dianhydride having fluorine group, polyimide powder A series It is composed of polyimide having a weight average molecular weight of (a-2) 100,000 g/mol or more and less than 250,000 g/mol, and the polyimide powder B is composed of (b-2) 250,000 g/mol It is composed of polyimide with a weight average molecular weight of 500,000 g/mol or less, and the weight ratio of the polyimide powder A/polyimide powder B is in the range of 10/90 to 90/10. The weight average molecular weight measured by mixing the imide powder A and the polyimide powder B is in the range of 160,000 to 350,000 g/mol. The polyimide powder according to claim 1 or 2, wherein the polyimide powder A and the polyimide powder B are composed of structural units derived from the same aromatic diamine compound and derived from the same It is composed of polyimide which is the structural unit of tetracarboxylic dianhydride. As claimed in claim 1 or 2, the polyimide powder, wherein, the polyimide powder A and the polyimide powder B are both obtained through the polymerization of polyimide, chemical imidization reaction, Formation of powder due to precipitation of polyimide and It consists of the polyimide produced in the drying step. The polyimide powder according to claim 1 or 2, wherein the average particle size measured for the mixture of the polyimide powder A and the polyimide powder B is in the range of 0.02 to 0.8 mm. The polyimide powder of claim 1 or 2, wherein the polyimide film with a thickness of 50 μm obtained from a solution dissolved in an organic solvent for film formation has a total light transmittance of 85% or more and a total light transmittance of -3~ Yellowness in the range of 3 (Yellow Index). A polyimide coating is characterized in that in an organic solvent, the polyimide powder according to any one of claims 1 to 6 is dissolved at a concentration of 1 to 30% by weight. A method for producing a polyimide paint, comprising: dissolving polyimide powder A in an organic solvent at a concentration of 1 to 30 wt %; and dissolving polyimide powder B in a manner of The paint dissolved in the organic solvent at a concentration of 1 to 30% by weight is mixed so that the weight ratio of the polyimide powder A/polyimide powder B is in the range of 10/90 to 90/10, and the polyimide powder is mixed. The imide powder A is composed of a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride, and is soluble in an organic solvent and has (a-1 ) 1.2dL/g or more and less than 2.1dL/g of polyimide with a reduced viscosity, the polyimide powder B is composed of A structural unit derived from at least one kind of aromatic diamine compound and a structural unit derived from at least one kind of tetracarboxylic dianhydride, and having (b-1) 2.1 dL/g or more 3.0 dL/g soluble in organic solvent The following polyimide with reduced viscosity is composed of at least one type of aromatic diamine compound, at least one type of aromatic diamine compound having a fluorine group, and at least one type of tetracarboxylic dianhydride, At least one kind of aromatic tetracarboxylic dianhydride having a fluorine group is contained. A method for producing a polyimide paint, comprising: dissolving polyimide powder A in an organic solvent at a concentration of 1 to 30 wt %; and dissolving polyimide powder B in a manner of The paint dissolved in the organic solvent at a concentration of 1 to 30% by weight is mixed so that the weight ratio of the polyimide powder A/polyimide powder B is in the range of 10/90 to 90/10, and the polyimide powder is mixed. The imide powder A is composed of a structural unit derived from at least one type of aromatic diamine compound and a structural unit derived from at least one type of tetracarboxylic dianhydride, and is soluble in an organic solvent and has (a-2 ) 100,000 g/mol or more and less than 250,000 g/mol of polyimide having a weight-average molecular weight of less than 250,000 g/mol, the polyimide powder B having a structural unit derived from at least one kind of aromatic diamine compound and Consists of (b-2) Polyimide having a weight average molecular weight of 100,000 g/mol or more and less than 250,000 g/mol, which is derived from at least one structural unit of tetracarboxylic dianhydride and is soluble in organic solvents , in the aforementioned at least one kind of aromatic diamine compound, including at least one kind of aromatic diamine compound having a fluorine group, At least 1 type of aromatic tetracarboxylic dianhydride having a fluorine group is included in the at least 1 type of tetracarboxylic dianhydride. A polyimide film, which is obtained by film-making as the polyimide coating of claim 7. The polyimide film of claim 10, wherein the total light transmittance is 85% or more, and the yellowness is in the range of -3 to 3.