CN-122011384-A - Polyamide acid solution, preparation method thereof and polyimide film

Abstract

The invention discloses a polyamic acid solution, a preparation method thereof and a polyimide film. The preparation method of the polyamic acid solution comprises the steps of mixing diamine, dianhydride, an auxiliary agent and a solvent to obtain a reaction system, and reacting the reaction system to obtain the polyamic acid solution, wherein the auxiliary agent comprises a composition of fatty acid and polypeptide, and the mass ratio of the fatty acid to the polypeptide is 1 (0.01-0.6). The method can lead the polyamic acid solution to have higher solid content, lower dynamic viscosity, proper molecular weight, better storage stability and better film forming property by introducing the auxiliary agent in the preparation process of the polyamic acid solution.

Inventors

• DONG XIAO
• LUO CHEN
• DONG YUE
• WANG JINKE
• Abuduheli Yakefu

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260512

Application Date

20241112

Claims (15)

1. 1. A method for preparing a polyamic acid solution, comprising the steps of: (I) Mixing diamine, dianhydride, an auxiliary agent and a solvent to obtain a reaction system; (II) reacting the reaction system obtained in the step (I) to obtain the polyamic acid solution; Wherein the auxiliary agent comprises a composition of fatty acid and polypeptide, and the mass ratio of the fatty acid to the polypeptide is 1 (0.01-0.6).
2. 2. The method for producing a polyamic acid solution according to claim 1, wherein the mass ratio of the auxiliary agent to the total amount of diamine and dianhydride is (0.01 to 0.5): 1.
3. 3. The method for producing a polyamic acid solution according to claim 1, wherein the fatty acid comprises a fatty acid having 4 or more carbon atoms.
4. 4. The method for producing a polyamic acid solution according to claim 3, wherein the fatty acid comprises one or more of sebacic acid, tridecylic acid, adipic acid, octadecanoic acid, hexadecanoic acid, butyric acid, caproic acid, capric acid and caprylic acid.
5. 5. The method for producing a polyamic acid solution according to claim 1, wherein the polypeptide comprises a polypeptide comprising 3 to 30 amino acid molecules.
6. 6. The method for producing a polyamic acid solution according to claim 5, wherein the polypeptide comprises one or more of a lysine polypeptide, a palmitoyl tripeptide, a palmitoyl tetrapeptide, a palmitoyl pentapeptide, an acetyl tripeptide, an acetyl tetrapeptide, an acetyl pentapeptide, an acetyl hexapeptide, an acetyl heptapeptide, and an acetyl octapeptide.
7. 7. The method for producing a polyamic acid solution according to claim 1, wherein the solvent comprises one or more of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide and hexamethylphosphoric triamide.
8. 8. The method for producing a polyamic acid solution according to claim 1, wherein the diamine comprises one or more of m-phenylenediamine, p-phenylenediamine, 4' -diaminodiphenyl ether, hydroquinone diether diamine, 4' -diaminodiphenyl sulfide, 4' -diaminodiphenyl methane, ethylenediamine, 1, 6-hexamethylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, and bisphenol a diether diamine.
9. 9. The method for producing a polyamic acid solution according to claim 1, wherein the dianhydride comprises one or more of pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, 3', 4' -benzophenone tetracarboxylic dianhydride, triphenyl diether dianhydride, diphenyl ether dianhydride, diphenyl sulfide dianhydride, 3', 4' -diphenyl ether tetracarboxylic dianhydride, hydroquinone diether dianhydride, hexafluorodianhydride, resorcinol diether dianhydride, bisphenol a diether dianhydride and 4,4' -oxydiphthalic dianhydride.
10. 10. The method for producing a polyamic acid solution according to claim 1, wherein the molar ratio of the diamine and the dianhydride is (0.99 to 1.01): (0.99 to 1.01), and the total mass of the diamine and the dianhydride is 10 to 30% of the total mass of the reaction system.
11. 11. The method for producing a polyamic acid solution according to claim 1, wherein the system temperature in steps (I) and (II) is-15 to 50 ℃.
12. 12. The method for producing a polyamic acid solution according to claim 1, wherein the reaction time in step (II) is 1 to 10 hours.
13. 13. A polyamic acid solution prepared by the method for preparing a polyamic acid solution according to any one of claims 1 to 12.
14. 14. The polyamic acid solution according to claim 13, wherein the polyamic acid solution has a kinetic viscosity of 10000cP or less, and/or The polyamic acid solution has a solid content of 10wt% or more, and/or The polyamic acid solution has a weight-average molecular weight of 30000 to 90000, and/or The polyamide acid solution has a change rate of weight average molecular weight of 1% or less before and after 960 hours of storage in an environment where the temperature is 25 ℃ and the pressure is normal pressure.
15. 15. A polyimide film obtained by subjecting the polyamic acid solution according to claim 13 or 14 to at least imidization treatment.

Description

Polyamide acid solution, preparation method thereof and polyimide film Technical Field The invention relates to the technical field of synthesis of polyamide acid, in particular to a polyamide acid solution, a preparation method thereof and a polyimide film. Background Polyimide (Polyimide) is a heterocyclic polymer (R-CO-NH-CO-R') containing imide groups in a molecular structure, has excellent heat resistance, strong corrosion resistance, good ageing resistance, good wear resistance, good insulating property, high insulation resistance, high heat distortion temperature and good thermal stability, can be used in a range from room temperature to 300 ℃, and is suitable for application under ultrahigh temperature, ultrahigh vacuum, corrosive environment and the like. Polyimide is mainly applied to the industries of aerospace, automobile manufacturing, medical appliances, pressure vessels, gas separation, flexible display and the like. The preparation method of polyimide comprises a one-step method, a two-step method and a three-step method, and most of the prior industrial production uses a simple two-step method, namely, aromatic dianhydride and diamine are polymerized in an aprotic polar solvent to obtain a polyamic acid solution, and then the polyamic acid solution is subjected to heat treatment or chemical imidization to obtain polyimide. The properties of the precursor, polyamide acid, therefore determine the quality of the final product. The solid content and viscosity of the polyamic acid solution are important factors influencing the processability, because in industrial production, the polyamic acid solution is synthesized and then needs to be subjected to spraying, casting, spinning and other methods to prepare products such as coatings, films and the like, and the proper viscosity and solid content can enable the performances of the products to be more excellent. In the actual operation process, a large number of hydrogen bonds are easy to form in the molecular chains and among the molecular chains of the polyamic acid, and the polyelectrolyte effect is enhanced by ionization of carboxylic acid groups, so that the polyamic acid solution with high solid content is usually extremely high in kinetic viscosity and even gelled, and is unfavorable for subsequent processing and application. Reducing the solids content of the polyamic acid solution can reduce its kinetic viscosity to some extent, but this approach can increase the amount of solvent used, affecting product quality resulting in reduced production efficiency. Thus, the preparation of low viscosity and high solids polyamide acid solutions is the basis for subsequent processing. In addition, molecular weight is one of the important factors affecting the properties of polyamic acid, and the molecular weight of polyamic acid can generally be between 3 and 9 ten thousand, which can exhibit better processability, but the relation among molecular weight, solid content and viscosity is affected by polymerized monomers, auxiliary agents, method selection and the like. In addition, the polyamic acid solution spontaneously degrades during storage. The essential reason for this degradation process is that the carboxylic acid hydroxyl groups in the polyamic acid and the amide carbonyl groups in the molecules undergo a depolymerization reaction through nucleophilic addition, and the moisture existing in the system hydrolyzes the acid anhydride end groups formed by depolymerization of the molecular chains to form two carboxylic acid groups, and this irreversible reaction causes a change in the properties of the polyamic acid, resulting in a short shelf life of the slurry and poor batch stability. The prior method for prolonging the preservation time of the polyamide acid mainly comprises dry preparation, ultralow-temperature storage, molecular sieve water absorption, molecular chain end capping and the like. However, the methods have the problems of complicated process, high reagent toxicity, high process cost and the like. CN101558102a is used for a method for preparing a polyamic acid solution and a polyamic acid solution. The method comprises reacting diamine with a molar excess of tetracarboxylic dianhydride relative to the amount of diamine in a solvent containing water in an amount exceeding 1/3 times the molar amount of tetracarboxylic dianhydride, thereby preparing a polyamic acid solution, and subsequently adding diamine and/or tetracarboxylic dianhydride to the polyamic acid solution so that the molar amount of diamine component becomes substantially equal to the molar amount of tetracarboxylic acid component, and further reacting the resulting mixture, thereby preparing a polyamic acid solution. The method can regulate the polyamic acid to have a given low molecular weight by regulating the water content of the reaction system, so that a polyamic acid solution having a high concentration and a low viscosity can be prepared with good reproducibilit