JP2000234023A - Polyimide precursor solution, its production, coating film obtained from it, and production of the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-concentration low-viscosity polyimide precursor solution by dissolving in a solvent a solute being a salt comprising a carboxylic acid having a specified structure and a diamine having a specified structure and to obtain a coating film having good properties. SOLUTION: Provided is a polyimide precursor solution prepared by dissolving a solute being a salt comprising 1 mol of (A) a carboxylic acid represented by formula I and 0.95-1.05 mol of (B) a diamine in a polar solvent such as N-methylpyrrolidone. After the solution is adjusted to a concentration of at least 30 wt.% and a viscosity of 100 P or below, it is applied to a substrate and imidized by heating to 200 deg.C or higher. Component A is prepared by reacting 1 mol of a tetracarboxylic acid dianhydride with 0.1-0.95 mol of a diamine, and component B is prepared by reacting 1 mol of a diamine with 0.1-0.95 mol of a tetracarboxylic acid dianhydride. In the formulae, R and R''' are each a tetravalent aromatic residue having a six-membered carbocyclic ring; R' and R'''' are each a divalent aromatic residue having a six-membered carbocyclic ring; R" is hydrogen or a 6C or lower monovalent organic group; and (n) and (m) are each 1-20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyimide precursor solution and a method for producing the same, and more particularly, to a polyimide coating film obtained from the polyimide precursor solution and a method for producing the same.

[0002]

2. Description of the Related Art Polyimides are useful for applications in the electronics field and are used as insulating films and protective coatings on semiconductor devices. In particular, wholly aromatic polyimides have greatly contributed to higher densities, multifunctionality, and the like in flexible circuit boards and integrated circuits because of their excellent heat resistance, mechanical properties, and electrical properties. As described above, when forming an interlayer insulating film or a protective film of a fine circuit, a polyimide precursor solution has been conventionally used. As the polyimide precursor solution, a polyamic acid solution represented by the following general formula is known.

[0003]

Embedded image

[0004] These polyamic acid solutions are produced by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride in a solvent.
No. 10999, JP-A-62-275165,
JP-A-64-5057, JP-B-2-38149, JP-B-2-38150, JP-A-1-299
871, JP-A-58-122920, JP-B1-34454, JP-A-58-185624, Journal of Polymer Science, Macromolecular Re.
views Vol.11 P.199 (1976), U.S. Pat.
No. 8, JP-B-3-4588, JP-B7-3
0247, JP-A-7-41556, JP-A-7-62095, JP-A-7-133349, JP-A-7-149896, JP-A-6-207
No. 014, JP-B-7-17870, JP-B-7
-17871, IBM Technical Disclosure Bulle
As disclosed in tinVol.20 No.6 P.2041 (1977) and the like, an aprotic polar solvent is used as a solvent, and as disclosed in JP-A-6-1915, a water-soluble solvent is used. Various solutions have been proposed, such as those using a mixed solvent selected from a water-soluble ether compound, a water-soluble alcohol compound, a water-soluble ketone compound and water.

As the polyimide precursor as a solute in the polyimide precursor solution, various polymers other than polyamic acid are known. For example, Macuromole
cules Vol.22 P.4477 (1989) and Polyimides and Other H
igh Temperature Polymers.P. 45 (1991) discloses a polyamic acid ester represented by the following general formula,

[0006]

Embedded image

[0007] Macuromolecules Vol.24 P.3475 (1991) discloses a trimethylsilyl polyamic acid ester represented by the following general formula:

[0008]

Embedded image

[0009] Journal of Polymer Science Part B Vol.
8 P.29 (1970), Journal of PolymerScience Part BV
ol.8 P.559 (1970), Chemical Society of Japan Vol.1972 P.1992, J
ournal of Polymer Science Polymer Chemistry Editio
n Vol.13 P.365 (1975) discloses bis (diethylamide) polyamic acid represented by the following formula.

[0010]

Embedded image

Each of the above polyimide precursor solutions is a solution of a polymer having a high degree of polymerization. When obtaining a polyimide coating film from these polymer solutions, generally, this polymer solution is coated on a substrate such as copper or glass, and the solvent is removed and imidation is performed by heating to obtain a polyimide coating film.

However, when a solution of a polymer having a high polymerization degree is applied as described above, the concentration of the solute must be reduced in order to obtain a viscosity at which the solution can be applied because of the degree of polymerization. was there. Also, to increase productivity, increasing the solute concentration increases the viscosity of the solution,
There is a problem that coating cannot be performed, and even if coating can be performed, there is a problem that a coating film or a film having excellent mechanical and thermal properties cannot be obtained. further,
The polymer solution is hard to withstand long-term storage, and it is extremely difficult to store the polymer solution for a long period of time while maintaining its degree of polymerization.

[0013]

In view of the above situation, an object of the present invention is to provide a polyimide precursor solution having a high concentration and a low viscosity, a method for producing the same, a polyimide coating film having good physical properties obtained therefrom, and a method for producing the same. It is to provide a method.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, when a specific monomer or oligomer is combined, even if it is not a polymer, a solution containing such a monomer or oligomer can be obtained well. It has been found that a polyimide coating having excellent physical properties can be obtained. That is, a polyimide precursor solution containing a monomer or oligomer salt composed of a carboxylic acid represented by the following general formula (1) and a diamine represented by the general formula (2) dissolves the monomer or oligomer salt at a high concentration. Despite the fact that it has a low viscosity, it has been found that a polyimide coating film of high strength can be obtained from this solution, and the present invention has been achieved based on these findings. Such a finding is a completely surprising finding in view of the fact that only a polyimide precursor having a high degree of polymerization has been known for constituting a polyimide precursor solution.

That is, the gist of the present invention is, first, that a salt comprising a carboxylic acid represented by the following general formula (1) and a diamine represented by the following general formula (2) is dissolved in a solvent as a solute. Which is a polyimide precursor solution.

[0016]

Embedded image

[In the formula, R and R ′ ″ represent a tetravalent aromatic residue having at least one carbon 6-membered ring, and may be the same or different, and the four carbonyl groups are Linked directly to different carbon atoms in the residue, two out of four are paired, bonded to adjacent carbon atoms in the carbon six-membered ring, R ′ and R ″ ″ Represents a divalent aromatic residue having at least one carbon 6-membered ring, which may be the same or different, R '' represents hydrogen or a monovalent organic group having 7 or less carbon atoms, n and m shows the integer of 1-20. ]

Second, 0.1 to 0.95 mol of a diamine represented by the following general formula (4) is reacted with 1 mol of a tetracarboxylic dianhydride represented by the following general formula (3) in a solvent. Then, a carboxylic dianhydride represented by the following general formula (5) is produced, and water or an alcohol is added to open the terminal acid anhydride group to form a carboxylic acid represented by the general formula (1). In a solvent or in another solvent system, 0.1 to 0.95 mol of a tetracarboxylic dianhydride represented by the following general formula (7) is reacted with 1 mol of a diamine represented by the following general formula (6). The diamine represented by the formula (2) is combined with the diamine represented by the general formula (2) so as to be 0.95 to 1.05 mol per 1 mol of the carboxylic acid represented by the general formula (1). Characterized by being dissolved in a solvent as a salt It is a manufacturing method of the body solution.

[0019]

Embedded image

[In the formula, R and R ′ ″ represent a tetravalent aromatic residue having at least one carbon 6-membered ring, and may be the same or different, and the four carbonyl groups are R 'and R "" are directly linked to different carbon atoms in the group, two of four are in pairs, and are bonded to adjacent carbon atoms in a six-membered carbon ring. Represents a divalent aromatic residue having at least one carbon 6-membered ring and may be the same or different, and R ″ represents hydrogen or a monovalent organic group having 7 or less carbon atoms, and n and m Represents an integer of 1 to 20. ]

Third, in a solvent, 0.1 to 1.95 mol of water or alcohol is added to 1 mol of tetracarboxylic dianhydride represented by the following general formula (3) to form one of the acid anhydride groups. And then adding 0.95 to 1.05 mol of a diamine represented by the following general formula (4) to form a carboxylic acid represented by the following general formula (1) and a diamine represented by the following general formula (2 ′) And dissolving them as a salt in a solvent.

[0022]

Embedded image

[Wherein, R represents a tetravalent aromatic residue having at least one carbon 6-membered ring, and the four carbonyl groups are directly linked to different carbon atoms in the R group. Two of them are paired and are bonded to adjacent carbon atoms in the six-membered carbon ring, and R ′ represents a divalent aromatic residue having at least one six-membered carbon ring; 'Represents hydrogen or a monovalent organic group having 7 or less carbon atoms, and n and m are 1 to
Indicates an integer of 20. Fourth, a polyimide coating film obtained from the polyimide precursor solution. Fifth, there is provided a method for producing a polyimide coating film, which comprises applying the polyimide precursor solution onto a substrate and heating the solution to imidize the polyimide precursor solution.

In the polyimide precursor solution,
In the general formulas (1) and (2), R and R ′ ″
Is a at least one member selected from the following group A, and R ′ and R ″ ″ are at least one member selected from the following group B, respectively.

[0025]

Embedded image

Further, the following polyimide precursor solution is a more preferred embodiment. That is, in the general formulas (1) and (2), a polyimide precursor solution in which R, R ', R "", and R "" is the following,

[0027]

Embedded image

In the general formulas (1) and (2),
R, R ′, R ′ ″, a polyimide precursor solution in which R ″ ″ is respectively:

[0029]

Embedded image

In the general formulas (1) and (2),
R, R ′, R ′ ″, a polyimide precursor solution in which R ″ ″ is respectively:

[0031]

Embedded image

In the general formulas (1) and (2),
A polyimide precursor solution in which R, R ', R'", and R""are the following is a more preferred embodiment.

[0033]

Embedded image

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. First, terms used in the present invention will be described. (1) Polyimide An organic polymer in which 80 mol% or more of the repeating unit of the polymer chain has an imide structure. And this organic polymer shows heat resistance. (2) Polyimide precursor An organic compound that becomes a polyimide by ring closure by heating or chemical action. Here, ring closure means that an imide ring structure is formed.

(3) Polyimide Precursor Solution The polyimide precursor is dissolved in a solvent, and contains a carboxylic acid represented by the general formula (1) and a diamine represented by the general formula (2) or a diamine represented by the general formula (2 ′). It is one in which a salt comprising the diamine shown is dissolved in a solvent as a solute. The diamine represented by the general formula (2 ′) is included in the diamine represented by the general formula (2). Here, the solvent is 25 ° C.
Means a liquid compound.

(4) Viscosity The rotational viscosity at 20 ° C. was measured using a DVL-BII type digital viscometer (B type viscometer) manufactured by Tokimec Co., Ltd. (5) Solute concentration It is a numerical value expressing the weight ratio of the polyimide precursor in the solution in percentage. (6) Polyimide coating film A polyimide coating solution obtained by coating the polyimide precursor solution of the present invention on a substrate such as copper, aluminum, or glass, heating and imidizing the polyimide precursor,
Among the polyimide coating films, those used in close contact with the substrate are referred to as polyimide coatings, and those used after being peeled off from the substrate are referred to as polyimide films.

Next, the present invention will be described. In the polyimide precursor solution of the present invention, a salt comprising a carboxylic acid represented by the general formula (1) and a diamine represented by the general formula (2) is dissolved in a solvent as a solute. In the carboxylic acid represented by the general formula (1), R represents a tetravalent aromatic residue having at least one carbon 6-membered ring, and four carbonyl groups represent R
It is directly linked to different carbon atoms in the group, two of the four are paired, and are bonded to adjacent carbon atoms in a 6-membered carbon ring, and specific examples of R include: Are included.

[0038]

Embedded image

The following are preferred as R.

[0040]

Embedded image

The following are more preferred as R.

[0042]

Embedded image

R ′ represents a divalent aromatic residue having at least one carbon 6-membered ring. Specific examples of R ′ include the following.

[0044]

Embedded image

The following are preferred as R '.

[0046]

Embedded image

The following are more preferred as R '.

[0048]

Embedded image

Examples of R ″ include hydrogen or a group derived from an alcohol described below, and a methyl group and an ethyl group are particularly preferable.

In the diamine represented by the general formula (2),
R "" represents a tetravalent aromatic residue containing at least one carbon 6-membered ring, and the four carbonyl groups are directly connected to different carbon atoms in the R "" group, and Are in pairs and are bonded to adjacent carbon atoms in the carbon 6-membered ring, and specific examples of R ″ ′ include those described above as R. Those shown are listed. Further, in a salt comprising a carboxylic acid represented by the general formula (1) and a diamine represented by the general formula (2),
R and R '''may be the same or different.

R ″ ″ represents a divalent aromatic residue having at least one carbon 6-membered ring. Specific examples of R ″ ″ include those described as R ′ above, and preferred examples also include those described above as R ′. Further, in the salt comprising the carboxylic acid represented by the general formula (1) and the diamine represented by the general formula (2), the same or different R ′ and R ″ ″ may be used. Good. In the diamine represented by the general formula (2 ′), R and R ′ are the same as those described above for R and R ′.

In the polyimide precursor solution of the present invention,
As the solvent, any solvent can be used as long as it dissolves a salt composed of a carboxylic acid represented by the general formula (1) and a diamine represented by the general formula (2) or the general formula (2 ′).

For example, aprotic polar solvents, ether compounds, water-soluble alcohol compounds and the like can be mentioned. Examples of the aprotic polar solvent include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, and the like. Methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene Glycol, triethylene glycol monoethyl ether,
Tetraethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, polypropylene glycol, tetrahydrofuran , Dioxane, 1,2-dimethoxyethane,
Diethylene glycol dimethyl ether, diethylene glycol diethyl ether and the like, and as the water-soluble alcohol compound, methanol, ethanol, 1-
Propanol, 2-propanol, tert-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, , 5-pentanediol, 2-butene-1,4-
Diols, 2-methyl-2,4-pentanediol,
Examples thereof include 1,2,6-hexanetriol and diacetone alcohol, and the above-mentioned solvents can be used alone or in combination of two or more. Among these, particularly preferred examples include N-methylpyrrolidone as a sole solvent,
N, N-dimethylformamide, N, N-dimethylacetamide, diethylene glycol monomethyl ether,
Examples of the mixed solvent include N-methylpyrrolidone and diethylene glycol monomethyl ether, N-methylpyrrolidone and methanol, N-methylpyrrolidone and 2-methoxyethanol, and the like.

In the present invention, the concentration of the polyimide precursor in the polyimide precursor solution is preferably 30% by weight or more.
It is more preferably at least 35% by weight, even more preferably at least 40% by weight. The viscosity of the polyimide precursor solution is 1
00 poise or less is preferable, 85 poise or less is more preferable, and 60 poise or less is further preferable.

To prepare the polyimide precursor solution in the present invention, a carboxylic acid represented by the general formula (1) or a carboxylic acid represented by the general formula (1) is added to the general formula (2) or the general formula (2 ′). The diamines shown are prepared or mixed in the same system in order or simultaneously, or prepared in separate systems and the respective solutions are mixed. Here, as a preferred example, a solution of a carboxylic acid represented by the general formula (1) is produced by reacting a tetracarboxylic dianhydride with a diamine and water or an alcohol in an aprotic polar compound. A method of preparing a diamine represented by the general formula (2) in the same system to obtain a polyimide precursor solution will be described.

First, in the aprotic polar compound, one mole of the aromatic tetracarboxylic dianhydride represented by the general formula (3) having R as a skeleton is represented by the general formula (4) having R 'as a skeleton. Are reacted with each other to produce a carboxylic dianhydride represented by the general formula (5). The reaction temperature at this time is preferably −30 to 70 ° C., and more preferably −20 to 40 ° C. Next, water or an alcohol is added to the reaction solution to open the acid anhydride group of the carboxylic dianhydride represented by the general formula (5) to obtain a carboxylic acid solution represented by the general formula (1). The reaction temperature at this time is preferably from 0 to 80 ° C, more preferably from 20 to 70 ° C. With respect to the amount of water or alcohol to be added, the molar amount or a slightly excessive amount is added to the anhydride group of the carboxylic acid dianhydride represented by the general formula (5). At this time, if necessary, dimethylaminoethanol or the like may be used as a catalyst.

The alcohols used here include the following, and among them, methyl alcohol and ethyl alcohol are preferred.

[0058]

Embedded image

Thereafter, an aromatic diamine represented by the general formula (6) having R ″ ″ as a skeleton and an aromatic tetracarboxylic acid represented by the general formula (7) having R ″ ′ as a skeleton are further added to the reaction solution. A dianhydride is added and reacted to form a diamine represented by the general formula (2). The reaction temperature at this time is -30 to 7
0 ° C is preferred, and -20 to 40 ° C is more preferred.

The reaction of the tetracarboxylic dianhydride with the diamine to obtain the carboxylic acid represented by the general formula (1) is carried out by adding 0.1 to 0.1 mol of the diamine to 1 mol of the tetracarboxylic dianhydride.
0.95 mol is preferred, more preferably 0.45-
0.9 mole. If the diamine is less than 0.1 or more than 0.95 mole per mole of tetracarboxylic dianhydride, the carboxylic acid represented by the general formula (1) tends to be difficult to obtain. The reaction of the tetracarboxylic dianhydride with the diamine to obtain the diamine represented by the general formula (2) is carried out in the range of 0.1 to 0.1 mol of the tetracarboxylic dianhydride with respect to 1 mol of the diamine.
95 mol is preferred, more preferably 0.45 to 0.9
Is a mole. If the amount of the tetracarboxylic dianhydride is less than 0.1 mol or more than 0.95 mol per 1 mol of the diamine, the diamine represented by the general formula (2) tends to be difficult to obtain. Further, the mixing ratio of the carboxylic acid represented by the general formula (1) and the diamine represented by the general formula (2) is preferably 0.95 to 1.05 mol of the diamine per 1 mol of the carboxylic acid. Outside this range, the desired salt tends to be difficult to obtain.

In synthesizing the carboxylic acid represented by the general formula (1) and the diamine represented by the general formula (2), the order of mixing the monomer and the solvent may be any order. When a mixed solvent is used as a solvent, different monomers are dissolved or suspended in each solvent, mixed, and reacted at a predetermined temperature and time under stirring to obtain a compound represented by the general formula (1). ) Or a diamine represented by the general formula (2). Further, for example, in an aprotic polar compound, 0.1 to 0.95 mol of water or alcohol is added to 1 mol of the aromatic tetracarboxylic dianhydride represented by the general formula (3) having R as a skeleton. In addition, a part of the acid anhydride group is ring-opened, and 0.95 to 1.05 mol of an aromatic diamine represented by the general formula (4) having R 'as a skeleton is added, and the compound is represented by the general formula (1). Even if a carboxylic acid and a diamine represented by the general formula (2 ′) are generated and dissolved as a salt,
Can be prepared. Regarding the reaction conditions at this time, the reaction temperature of the aromatic tetracarboxylic dianhydride with water or alcohol is preferably 0 to 80 ° C, more preferably 20 to 70 ° C. In this case, if necessary, dimethylaminomethanol or the like may be used as a catalyst. The reaction temperature at the time of adding the diamine is preferably −30 to 70 ° C.,
40 ° C. is more preferred.

Further, the polyimide precursor solution of the present invention may contain, if necessary, fillers such as organosilane, pigment, conductive carbon black and metal particles, abrasives, dielectrics, lubricants and the like. Other known additives can be added as long as the effects of the present invention are not impaired. Also, other polymers and, for example, water-insoluble ethers, alcohols,
Solvents such as ketones, esters, halogenated hydrocarbons, and hydrocarbons can be added as long as the effects of the present invention are not impaired.

The polyimide coating is obtained by applying a polyimide precursor solution to a substrate by various methods, drying and removing the solvent, obtaining a polyimide precursor coating, and imidizing the polyimide precursor. . The imidization is preferably performed by heating, and is performed by heating at 200 ° C. or higher, preferably 250 ° C. or higher, more preferably 300 ° C. or higher, for 5 minutes or longer, preferably 30 minutes or longer. To mold a polyimide film from a polyimide precursor solution, extrude it from a slit-shaped nozzle, apply it on a substrate with a bar coater, etc., dry it to remove the solvent, imidize it, It can be manufactured by peeling off from. To obtain a polyimide coating, a polyimide precursor solution is applied onto a substrate by a conventionally known spin coating method, spray coating method, immersion method, or the like, dried, and the solvent is removed, followed by imidization. .

The polyimide precursor solution or polyimide coating film of the present invention (polyimide film or polyimide coating)
Is used, for example, in the production of heat-resistant insulating tapes, heat-resistant adhesive tapes, high-density magnetic recording bases, capacitors, films for FPC (flexible printed circuit boards), and the like. Further, for example, it is used for manufacturing molding materials and molded products such as sliding members filled with fluororesin or graphite, structural members reinforced with glass fiber or carbon fiber, bobbins of small coils, sleeves, and tubes for terminal insulation. . It is also used for manufacturing laminated materials such as insulating spacers for power transistors, magnetic head spacers, spacers for power relays, and spacers for transformers. In addition, for wire and cable insulation coating,
It is used to manufacture enamel coating materials such as solar cells, low-temperature storage tanks, space insulation, integrated circuits, slot liners, and the like. Further, it is used for the production of ultrafiltration membranes, reverse osmosis membranes, and gas separation membranes. It is also used for the production of heat-resistant yarns, woven fabrics and nonwoven fabrics.

[0065]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 2.96 g of 4,4'-diaminodiphenyl ether (1
4.8 mmol) with N, N-dimethylacetamide 4
It melt | dissolved in 5.0 g and stirred at room temperature. To this, 6.45 (29.6 mmol) of pyromellitic dianhydride was added over 1 minute, and the mixture was stirred at room temperature for 1 hour. 1.42 g of methanol
(44.4 mmol) and 0.07 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a carboxylic acid represented by the following formula.

[0067]

Embedded image

After cooling to room temperature, 5.93 g (29.6 mmol) of 4,4'-diaminodiphenyl ether was added and dissolved, and pyromellitic dianhydride 3.23 was added thereto.
g (14.8 mmol) was added over 1 minute, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). The viscosity of this solution was measured and found to be 1.49 poise. Using a film applicator, this solution was cast on a glass plate to a thickness of 50 μm, and dried at 80 ° C. for 5 hours under a nitrogen atmosphere.
Heat imidization was performed at 300 ° C. for 5 hours in a nitrogen atmosphere.
When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is 13.1 μm, and the tensile strength is 9.6 kg.
/ Mm ² .

Example 2 3.89 g of 4,4'-diaminodiphenyl ether (1
9.4 mmol) with N, N-dimethylacetamide 4
It melt | dissolved in 5.0 g and stirred at room temperature. To this, 5.65 (25.9 mmol) of pyromellitic dianhydride was added over 1 minute, and the mixture was stirred at room temperature for 1 hour. 0.62 g of methanol
(19.4 mmol) and 0.03 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours. After cooling to room temperature, 5.19 g (25.9 mmol) of 4,4′-diaminodiphenyl ether was added and dissolved,
To this, 4.24 g of pyromellitic dianhydride (19.4 m
mol) for 1 minute, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). When the viscosity of this solution was measured, it was determined that 9.
It was 18 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then dried under a nitrogen atmosphere.
Heat imidation was performed at 00 ° C. for 5 hours. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is 13.8
μm, and the tensile strength was 10.2 kg / mm ² .

Example 3 29.02 g of 4,4'-diaminodiphenyl ether
(145 mmol) was dissolved in 300 g of N, N-dimethylacetamide and stirred at room temperature. To this, 35.13 (161 mmol) of pyromellitic dianhydride was added over 1 minute, and the mixture was stirred at room temperature for 1 hour. 1.55 g of methanol
(48.3 mmol) and 0.08 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours. After cooling to room temperature, 32.25 g (161 mmol) of 4,4′-diaminodiphenyl ether was added and dissolved,
31.62 g of pyromellitic dianhydride (145 m
mol) for 1 minute, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). When the viscosity of this solution was measured,
It was 3.6 poise. Using a film applicator, this solution was cast on a glass plate with a thickness of 50 μm,
After drying at 80 ° C. for 5 hours in a nitrogen atmosphere, heat imidization was performed at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is 14.
2 μm, and the tensile strength was 11.0 kg / mm ² .

Example 4 9.68 g of pyromellitic dianhydride (44.4 mmol)
l) was suspended in 45 g of N, N-dimethylacetamide, and 1.42 g (44.4 mmol) of methanol and 0.073 g of dimethylaminoethanol were added.
The mixture was stirred on a water bath for 2 hours. 8.89 g (44.4 mmol) of 4,4′-diaminodiphenyl ether was added, and the mixture was further stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). When the viscosity of this solution was measured, it was 0.319 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film was 13.5 μm, and the tensile strength was 9.5 kg / mm ² .

Example 5 9.87 g (45.2 mmol) of pyromellitic dianhydride
l) was suspended in 45 g of N, N-dimethylacetamide, and 0.0725 g (22.6 mmol) of methanol and 0.036 g of dimethylaminoethanol were added.
The mixture was stirred on a 0 ° C. water bath for 2 hours. 9.06 g (45.2 mmol) of 4,4′-diaminodiphenyl ether was added, and the mixture was further stirred for 2 hours on a 70 ° C. water bath to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). When the viscosity of this solution was measured, it was 1.30 poise.
This solution was cast on a glass plate to a thickness of 50 μm using a film applicator, and the solution was cast at 80 ° C. in a nitrogen atmosphere at 5 ° C.
After drying for an hour, imidization was performed by heating at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film was 13.7 μm, and the tensile strength was 9.8 kg / mm ² .

Comparative Example 1 16.4 g of 4,4'-diaminodiphenyl ether
(80.0 mmol) was dissolved in 78.05 g of N, N-dimethylacetamide and kept at room temperature. To this, 17.45 g (80.0 mmol) of pyromellitic dianhydride was added in 2 portions.
The solution was gelled as it was added slowly over time and stirring continued for another 6 hours. (Solute concentration 30% by weight)

Example 6 4.38 g of 4,4'-diaminodiphenyl ether (2
1.9 mmol) with N, N-dimethylacetamide 5
It was dissolved in 0.0 g and stirred at room temperature. To this, biphenyltetracarboxylic dianhydride 12.88 (43.8 mm
ol) for 1 minute and stirred at room temperature for 1 hour. 2.10 g (65.7 mmol) of methanol and 0.11 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a carboxylic acid represented by the following formula.

[0075]

Embedded image

After cooling to room temperature, 8.76 g (43.8 mmol) of 4,4'-diaminodiphenyl ether was added and dissolved, and 6.44 g (21.9 mmol) of biphenyltetracarboxylic dianhydride was added thereto for 1 minute. In addition,
After stirring on a 70 ° C. water bath for 2 hours, a uniform yellow-orange transparent solution was obtained (solute concentration: 40% by weight). When the viscosity of this solution was measured, it was 8.06 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film was 16.1 μm, and the tensile strength was 18.7 kg / mm ² .

Example 7 5.72 g of 4,4'-diaminodiphenyl ether (2
8.6 mmol) with N, N-dimethylacetamide 5
It was dissolved in 0.0 g and stirred at room temperature. To this, 11.21 g of biphenyltetracarboxylic dianhydride (38.1 m
mol) for 1 minute and stirred at room temperature for 1 hour. 0.92 g (9.53 mmol) of methanol and 0.05 g of dimethylaminoethanol were added, and 2
Stirred for hours. After cooling to room temperature, 7.63 g (38.1 mmol) of 4,4'-diaminodiphenyl ether
Was added and dissolved. To this, 8.40 g (28.6 mmol) of biphenyltetracarboxylic dianhydride was added over 1 minute, and the mixture was stirred for 2 hours on a 70 ° C. water bath to obtain a uniform yellow-orange transparent solution. (Solute concentration 40% by weight). When the viscosity of this solution was measured, it was 109 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film was 15.8 μm, and the tensile strength was 18.2 kg / mm ² .

Comparative Example 2 16,4 g of 4,4'-diaminodiphenyl ether
(80.0 mmol) was dissolved in 92.2 g of N, N-dimethylacetamide and kept at room temperature. 23.5 g of biphenyltetracarboxylic dianhydride (80.0 mmol
1) was added slowly over 2 hours and stirring was continued for another 6 hours, at which time the solution gelled. (Solute concentration 30% by weight)

Example 8 2.03 g of paraphenylenediamine (18.8 mmol)
1) was dissolved in 55.0 g of N, N-dimethylacetamide and stirred at room temperature. To this was added 11.05 (37.6 mmol) of biphenyltetracarboxylic dianhydride for 1 minute, and the mixture was stirred at room temperature for 1 hour. Methanol 1.80
g (56.4 mmol) and 0.09 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a carboxylic acid represented by the following formula.

[0080]

Embedded image

After cooling to room temperature, 4.06 g (37.6 mmol) of paraphenylenediamine was added and dissolved.
5.52 g of biphenyltetracarboxylic dianhydride was added to this.
(18.8 mmol) was added over 1 minute, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 30% by weight). When the viscosity of this solution was measured, it was 1.08 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is 12.7 μm, and the tensile strength is 25.6 kg.
/ Mm ² .

Example 9 2.67 g of paraphenylenediamine (24.7 mmol)
1) was dissolved in 55.0 g of N, N-dimethylacetamide and stirred at room temperature. To this, biphenyltetracarboxylic dianhydride 9.68 (32.9 mmol) was added over 1 minute, and the mixture was stirred at room temperature for 1 hour. 0.79 g of methanol
(24.7 mmol) and 0.04 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours. After cooling to room temperature, 3.56 g of paraphenylenediamine
(32.9 mmol) was added and dissolved, and 7.26 g (24.7 mm) of biphenyltetracarboxylic dianhydride was added thereto.
ol) in 1 minute and stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 3).
0% by weight). When the viscosity of this solution was measured, 8.2
5 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours under a nitrogen atmosphere, and then dried under a nitrogen atmosphere.
Heat imidation was performed at 0 ° C. for 5 hours. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is 12.9μ.
m, and the tensile strength was 27.3 kg / mm ² .

Comparative Example 3 8.7 g (80.0 mmol) of paraphenylenediamine
Is dissolved in 75.1 g of N, N-dimethylacetamide,
It was kept at room temperature. To this, 23.5 g (80.0 mmol) of biphenyltetracarboxylic dianhydride was gradually added over 2 hours, and stirring was further continued for 6 hours, whereby the solution gelled. (Solute concentration 30% by weight)

Example 10 4.25 g of 3,4'-diaminodiphenyl ether (2
1.2 mmol) with N-methyl-2-pyrrolidone 5
It was dissolved in 0.0 g and stirred at room temperature. To this, oxydiphthalic dianhydride 13.2 (42.4 mmol) was added over 1 minute, and the mixture was stirred at room temperature for 1 hour. 2.04 methanol
g (63.8 mmol) and 0.10 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a carboxylic acid represented by the following formula.

[0085]

Embedded image

After cooling to room temperature, 8.50 g (42.4 mmol) of 3,4'-diaminodiphenyl ether was added and dissolved, and oxydiphthalic dianhydride 6.5 was added thereto.
8 g (21.2 mmol) was added over 1 minute, and the mixture was stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration: 40% by weight). The viscosity of this solution was measured and found to be 11.1 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. This polyimide film has a thickness of 15.1 μm and a tensile strength of 14.1 μm.
It was 3 kg / mm ² .

Example 11 3.55 g of 3,4′-diaminodiphenyl ether (1
7.8 mmol) with N-methyl-2-pyrrolidone 5
It was dissolved in 0.0 g and stirred at room temperature. To this was added 7.34 g (23.7 mmol) of oxydiphthalic dianhydride in 1
And stirred at room temperature for 1 hour. Methanol 0.5
7 g (17.8 mmol) and 0.03 g of dimethylaminoethanol were added, and the mixture was stirred on a 70 ° C. water bath for 2 hours. After cooling to room temperature, 4.74 g (23.7 mmol) of 3,4'-diaminodiphenyl ether was added and dissolved, and 5.51 g of oxydiphthalic dianhydride was added thereto.
7.8 mmol) over 1 minute and stirred on a 70 ° C. water bath for 2 hours to obtain a uniform yellow-orange transparent solution (solute concentration 30% by weight). When the viscosity of this solution was measured, it was 4.2 poise. This solution was cast on a glass plate with a thickness of 50 μm using a film applicator, dried at 80 ° C. for 5 hours in a nitrogen atmosphere, and then heated and imidized at 300 ° C. for 5 hours in a nitrogen atmosphere. When the obtained coating film was peeled off from the glass plate, a polyimide film was obtained. The thickness of this polyimide film is
13.1 μm and tensile strength of 14.4 kg / m
m ² .

Comparative Example 4 16,00 g of 3,4'-diaminodiphenyl ether
(80.0 mmol) in N-methyl-2-pyrrolidone 9
Dissolved in 5.2 g and kept at room temperature. To this, 24.8 g (80.0 mmol) of oxydiphthalic dianhydride was gradually added over 2 hours, and stirring was further continued for 6 hours. As a result, the solution gelled. (Solute concentration 30% by weight)

[0089]

As described above, the polyimide precursor solution of the present invention has a low viscosity even though the solute is not a polymer but a monomer or oligomer salt and is dissolved at a high concentration. It is. Further, the polyimide coating film obtained from the polyimide precursor solution of the present invention has good physical properties. Therefore, the present invention has an excellent effect in a spin coating method used for forming an interlayer insulating film of a large-scale integrated circuit or the like or a protective film. Further, according to the method for producing a polyimide precursor solution of the present invention, the polyimide precursor solution can be easily produced, and according to the method for producing a polyimide film, a polyimide film can be easily produced. .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiro Eguchi 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Central Research Laboratory (72) Inventor Fumiko Okui 23 Uji Kozakura, Uji City, Kyoto Unitika Central In the laboratory (72) Inventor Keitaro Seto 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Central Research Laboratory (72) Inventor Soichiro Kishimoto 23 Uji Kozakura Uji City, Kyoto Prefecture Unitika Central Research Laboratory (72) Invention Person Yoshiaki Echigo 23 Uji Kozakura, Uji City, Kyoto Prefecture Inside Unitika's Central Research Laboratory

Claims (7)

[Claims] 1. A polyimide precursor solution, wherein a salt comprising a carboxylic acid represented by the following general formula (1) and a diamine represented by the following general formula (2) is dissolved in a solvent as a solute. Embedded image [In the formula, R and R ′ ″ represent a tetravalent aromatic residue having at least one carbon 6-membered ring, and may be the same or different. , Two of four are paired, are bonded to adjacent carbon atoms in a six-membered carbon ring, and R ′ and R ″ ″ are at least One carbon 6
A divalent aromatic residue having a membered ring, which may be the same or different, R '' represents hydrogen or a monovalent organic group having 7 or less carbon atoms, and n and m are integers of 1 to 20 Is shown. ] 2. In the general formulas (1) and (2), R and R ″ ″ are each at least one selected from the following group A, and R ′ and R ″ ″ are each The polyimide precursor solution according to claim 1, wherein the solution is at least one selected from the following group B: Embedded image 3. The polyimide precursor solution according to claim 1, wherein the solute concentration is 30% by weight or more and the viscosity is 100 poises or less. 4. In a solvent, 0.1 to 0.95 mol of a diamine represented by the following general formula (4) is reacted with 1 mol of a tetracarboxylic dianhydride represented by the following general formula (3), A carboxylic acid dianhydride represented by the following general formula (5) is generated, and water or an alcohol is added to open a terminal acid anhydride group to form a carboxylic acid represented by the general formula (1). In another solvent system, 0.1 to 0.95 mol of a tetracarboxylic dianhydride represented by the following general formula (7) is reacted with 1 mol of a diamine represented by the following general formula (6) to form a compound represented by the general formula ( The diamine represented by the formula (2) is combined with the diamine represented by the formula (2) in an amount of 0.95 to 1.05 mol per 1 mol of the carboxylic acid represented by the formula (1) to form a salt. 2. The polymer according to claim 1, wherein the polymer is dissolved in a solvent. A method for producing a imide precursor solution. Embedded image [In the formula, R and R ′ ″ represent a tetravalent aromatic residue having at least one carbon 6-membered ring, and may be the same or different. Linked directly to different carbon atoms, two of four being paired, linked to adjacent carbon atoms in a six-membered carbon ring, and R ′ and R ″ ″ are at least 1 A divalent aromatic residue having two carbon 6-membered rings, which may be the same or different, R '' represents hydrogen or a monovalent organic group having 7 or less carbon atoms, and n and m are 1 to Indicates an integer of 20. ] 5. In a solvent, 0.1 to 1.95 mol of water or an alcohol is added to 1 mol of a tetracarboxylic dianhydride represented by the following general formula (3) to partially remove an acid anhydride group. The ring is opened, and the diamine represented by the following general formula (4)
A carboxylic acid represented by the following general formula (1) and a diamine represented by the following general formula (2 ′) are formed by adding 5 to 1.05 mol, and these are dissolved in a solvent as a salt. A method for producing a polyimide precursor solution according to claim 1. Embedded image [Wherein, R represents a tetravalent aromatic residue having at least one carbon 6-membered ring, and four carbonyl groups are directly linked to different carbon atoms in the R group, and two of the four Each of which is paired and is attached to an adjacent carbon atom in the six-membered carbon ring, R ′ is a divalent aromatic residue having at least one six-membered carbon ring, and R ″ is hydrogen Alternatively, it represents a monovalent organic group having 7 or less carbon atoms, and n and m each represent an integer of 1 to 20. ] 6. A polyimide coating film obtained from the polyimide precursor solution according to claim 1. 7. A method for producing a polyimide coating film, comprising applying the polyimide precursor solution according to claim 1 onto a substrate, and heating and imidizing the substrate.