JPH0368056B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a soluble polyimide that has high heat resistance, is soluble in organic solvents, and can be formed into a film. Prior Art It is already known that polyimide polymers have excellent properties such as heat resistance and chemical resistance, and are particularly useful for wire coatings, films, adhesives, etc. used at high temperatures. Useful for applications. Conventionally, methods for producing polyimide include producing polyamic acid from a tetracarboxylic acid component and a diamine component, molding the polyamic acid, and then imidizing the polyamic acid using various methods. A method (two-step manufacturing method for polyimide) is known. However, although polyamic acid, which is the intermediate described above, has excellent heat resistance, it has poor stability during storage and needs to be stored at low temperatures because it increases viscosity and gels even at room temperature. .
Furthermore, if left for a long period of time, a portion of the polyimide undergoes dehydration and ring closure, resulting in insolubilization and cloudiness, which is a drawback. A method for producing and processing an imide polymer that corrects these drawbacks can be achieved by synthesizing a high molecular weight, solvent-soluble polyimide. Regarding this soluble polyimide, for example, Japanese Patent Publication No. 47-37706 and Japanese Patent Application Laid-open No. 56-36520,
Examples are disclosed in which an aliphatic compound is used as the tetracarboxylic acid component or the diamine component. However, in both cases, heat resistance, which is the most important feature of polyimide, decreases. In addition, in the case of the polyimide described in JP-A-50-113597, although high heat resistance can be maintained, the only agents in which this polyimide is soluble are phenolic solvents such as m-cresol and xylenol. . With such solvents, it is difficult to dissolve polyimide at a high concentration, and it is difficult to produce a polyimide film with excellent mechanical properties. Problems to be Solved by the Invention An object of the present invention is to first provide a polyimide that is soluble in organic solvents, including solubility not limited to phenolic solvents, and that maintains high heat resistance. . Means for Solving the Problems This invention is intended to solubilize polyimide. However, solubility and heat resistance have contradictory characteristics, and generally, as solubility increases, heat resistance decreases. Therefore, in the present invention, research has been conducted to make the polyimide soluble while maintaining a high glass transition temperature and decomposition temperature, and the following soluble polyimide has been developed. That is, the present invention is substantially represented by the formula -(X-Y-), where X represents (A) and (B), and the molar ratio of (A) and (B) is from 1:99 to 70:30, Y is a polyimide having a chain member represented by (C), and 0.5 g of the polyimide is o-
The intrinsic viscosity (ηinh) based on the value measured at 30℃ of a solution dissolved in 100ml of chlorphenol is 0.25dl/
It is a soluble polyimide characterized by having a molecular weight of at least 100 g. Effect Structure X constituting the above-mentioned soluble polyimide is
It consists of component (A) and component (B), and structure Y is component (C). The structures of polymers synthesized from these components include polymers -(A-C-) and -(B-
C-) is considered, but although polymer (A-C-) has good heat resistance, it has no solubility in solvents. In addition, in the case of polymer (B-C-), although it is soluble in a solvent, its heat resistance decreases. Therefore, in the present invention, it is limited to polyimide having the above-mentioned structure, and it has both heat resistance and solubility. A polyimide that is composed of components (A) and (B) is a polyimide that combines the above (A) and (B).
The molar ratio of (B) is from 1:99 to 70:30, preferably 1:
It is better to have a ratio of 60:40 to 99. (A) Component is pyromellitic acid dianhydride, (B)
Ingredients: benzophenonetetracarboxylic acid 2
Obtained using anhydride. As component (C),
It can be obtained using 9,9-bis(4-aminophenyl)fluorene or a derivative thereof in which a substituent such as an alkyl group is introduced into the aromatic ring portion thereof. In addition, the polyimide of the present invention can be prepared by dissolving 0.5 g of polyimide in 100 ml of o-chlorophenol.
Intrinsic viscosity (ηinh) measured at 30℃ is 0.25
dl/g or more, preferably 0.30 dl/g or more, more preferably 0.35 dl/g or more. If the intrinsic viscosity is less than 0.25 dl/g, the degree of polymerization will be low, resulting in poor moldability and processability. That is, it is difficult to form into a film or the like, and its physical properties such as tensile strength are sufficient. The soluble polyimide of the present invention can be dissolved in at least one of dimethylacetamide, N-methylpyrrolidone, m-cresol, o-chlorophenol, and methylene chloride. Furthermore, in polyimide
In the ratio of component (A) to component (B), as the proportion of component (B) increases, solubility also increases. In order to produce this soluble polyimide, for example, m-cresol or o-chlorophenol is used as a solvent, and pyromellitic acid 2 is added to a 9,9-bis(4-aminophenyl)fluorene solution.
A mixture of anhydride and benzophenonetetracarboxylic dianhydride is gradually added as a solid, and then for example at 20-50°C for 2-4 hours, at 120-180°C for 1-3 hours, and at 180-220°C for 1 hour. It can be obtained by heating for about 3 hours. At this time, the water produced in the final stage of reaction must be removed from the system using azeotropy or the like. By the method described above, a polyimide with high heat resistance and solubility can be obtained. Examples and comparative examples of the present invention will be shown below and explained in more detail. Examples Example 1 0.65 g of pyromellitic acid dianhydride, 0.95 g of benzophenonetetracarboxylic acid dianhydride, namely A,
The molar ratio of component B is 5:5, and these and 9,9-
2.09 g of bis(4-aminophenyl)fluorene was suspended in 40 ml of m-cresol, stirred at 40°C for 2 hours while passing N ₂ gas, and after confirming that it had become a homogeneous solution, the mixture was stirred at 150°C for 2 hours. The solution was further heated to 190° C., a distillation device was attached to the reaction apparatus, and m-cresol was added to the reaction system in an amount equal to the amount of distilled liquid, while stirring for 2 hours and cooling to room temperature. The obtained solution was homogeneous and was cast onto a glass plate to form a film. The film-like polyimide did not exhibit a glass transition temperature, had a softening temperature of 555°C, and had excellent heat resistance. This polyimide was dissolved in dimethylacetamide, N-methylpyrrolidone, m-cresol, and methylene chloride, respectively. In addition, the intrinsic viscosity (ηinh) was measured using a solution of 0.5 g of the obtained polyimide dissolved in 100 ml of o-chlorophenol in a constant temperature water bath at 30°C.
It was 0.53 dl/g. The infrared absorption spectrum of the obtained polyimide clearly showed absorption by imide rings at 1720 and 1780 cm ^-1 . Examples 2 to 6 Polyimides were produced in the same manner as in Example 1, except that the amounts of pyromellitic dianhydride (A) and benzophenonetetracarboxylic dianhydride (B) were changed as follows. The results of Example 1 are also shown in Table 1. The decomposition onset temperature is the temperature at which weight loss begins as measured on a thermobalance (TG). The tensile strength of the polyimide of Example 3 is 10.0Kgf/
mm ² tensile modulus 410Kgf/mm ² , volume resistivity 2.6×10 ¹⁵
Ωcm, total light transmission amount was 86.5%.

[Table] Comparative Examples 1, 2 1.30 g of pyromellitic acid dianhydride using the same conditions as Example 1, with only the A component instead of the A and B components of the raw material.
(Comparative Example 1) and using only 1.93 g of benzophenonetetracarboxylic dianhydride as the B component (Comparative Example 2). The product of Comparative Example 1 showed no solubility in organic solvents. In addition, when benzophenonetetracarboxylic dianhydride of Comparative Example 2 was used, it showed solubility in dimethylacetamide, methylene chloride, N-methylpyrrolidone, and m-cresol, and had an intrinsic viscosity (ηinh) of 0.41 dl/g. The glass transition temperature was 360°C. Comparative Example 3 A benzophenonetetracarboxylic acid type polyimide was synthesized using a conventional two-step method. To a solution of 2.09 g of 9,9-bis(4-aminophenyl)fluorene dissolved in 40 ml of dimethylacetamide, benzophenonetetracarboxylic acid 2
1.93 g of anhydride was added slowly. Thereafter, after stirring at room temperature for 20 hours, the obtained polyamic acid was cast onto a glass plate and a polyimide film was produced by a conventional method of accelerating the reaction by firing, that is, heating. The glass transition temperature of the obtained polyimide is 340℃
It was hot. Effects of the Invention There are almost no soluble polyimides currently in practical use. Although polyimide has excellent physical properties, its range of use is limited, probably because it has considerable disadvantages in terms of processing, such as solubility. Therefore, polyamic acid, which is a precursor of polyimide, has been used so far and polyimide is produced by firing, but the polyimide of the present invention has improved solubility in solvents, which conventional polyimide had, and Since it has good heat resistance, it is widely used in electrical and electrolytic decomposition, etc. Furthermore, the polyimide of the present invention is a novel product that overcomes the problems of existing polyimides, and can be widely applied to various uses such as heat-resistant paints, coatings, and hollow fibers, and is industrially useful.

Claims (1)

[Claims] 1 Substantially represented by the formula -(X-Y-), where X is (A)
and (B), with a molar ratio of (A) and (B) of 1:99.
70:30, Y is a polyimide having a chain member represented by (C), and the value is measured at 30°C from a solution of 0.5 g of the polyimide dissolved in 100 ml of o-chlorophenol. A soluble polyimide having an intrinsic viscosity (ηinh) of 0.25 dl/g or more. 2. The soluble polyimide according to claim 1, wherein the molar ratio of structural formulas (A) and (B) is within the range of 1:99 to 60:40. 3. A soluble polyimide according to claim 1 or 2, which dissolves in one or more solvents among dimethylacetamide, N-methylpyrrolidone, m-cresol, o-chlorophenol, and methylene chloride.