JP2915301B2 - Polyimide precursor composition, polyimide composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel thixotropic polyimide precursor composition suitable for screen printing, a process for producing the same, and a novel polyimide composition obtained therefrom.

[0002]

2. Description of the Related Art Polyimide is coated on the surface of various materials as a heat-resistant material.
A polyimide containing aminophenoxy) phenyl) sulfone as an essential component is known from JP-B-48-18960, and describes that the coating film is excellent in abrasion resistance and alkali resistance. As a method of forming a relief pattern on a coating film, a method of performing patterning by wet or dry processing after spin coating, or a method of performing patterning simultaneously with coating by screen printing, and the like are known.
From the viewpoint of shortening the process, the latter screen printing method is desired.

The coating material used is preferably a Newtonian fluid in spin coating. In screen printing, in order to achieve both a filling property of the plate pattern into the opening and a shape retaining property of the formed relief pattern. It is preferred that the Bingham fluid be thixotropic.

It is known that such characteristics required for screen printing can be obtained by a system in which a filler powder is mixed and dispersed in a general Newtonian fluid. Also, a composition in which an inorganic or organic powder is kneaded with these varnishes is known.

However, the polyamic acid solution or polyimide varnish used is made to have a high concentration in order to enhance the shape retention of the pattern. As a result, the filler powder is uniformly mixed with the solution having a necessarily high viscosity. It is difficult to knead and disperse, and Japanese Patent Publication No. 2-1192 discloses a mixed solution of a tetracarboxylic acid component and a diamine component at 150 ° C.
Polymerization under the above heating, to prepare a suspension solution containing a polyimide fine powder functioning as a filler powder, and subsequently by adding and reacting tetracarboxylic acid and diamine in this suspension solution, the polyimide fine powder is A method for obtaining a well dispersed polyimide precursor varnish is disclosed.

Further, the relief pattern formed from the polyimide composition in which the filler powder is dispersed is inferior in mechanical strength as compared with polyimide in which the filler is not kneaded, and is therefore disclosed in JP-A-4-85379 and JP-A-4-153261. Japanese Patent Application Laid-Open No. 4-248871 discloses that a polyimide powder prepared or isolated chemically or physically is roll-kneaded with a polyamic acid varnish so that the filler powder is dispersed at room temperature to secure printing characteristics. It describes a polyimide composition in which the filler powder forms a homogeneous composition with the varnish resin during firing to improve the mechanical strength.

[0007]

Problems to be Solved by the Invention Japanese Unexamined Patent Publication No. 4-8 / 1990
The compositions containing bis (4- (3-aminophenoxy) phenyl) sulfone described in the specifications of JP-A-5379 and JP-A-4-248871 have a thixotropic property due to dispersion of a filler powder, and a screen. It is suitable for printing, but in its production, the filler powder must be dispersed in a high-viscosity liquid by stirring, mixing, kneading, and other mechanical treatments to maintain productivity and stabilize quality. It involves a big problem. Furthermore, the composition in which the filler powder is dispersed to exhibit thixotropy has insufficient filling properties in the plate openings in high-definition screen printing.

An object of the present invention is to provide a polyimide precursor composition containing bis (4- (3-aminophenoxy) phenyl) sulfone as an essential component, by imparting thixotropy to the screen printing, which is excellent in forming a relief pattern. It is an object of the present invention to provide a polyimide precursor composition for use and to provide a simple production method thereof.

[0009]

Means for Solving the Problems The present inventors have conducted research on applying a polyimide resin composition to a printing paste. As a result, a specific polyimide precursor composition generally imparts thixotropic properties. In order to convert the paste composition into a translucent or opaque homogeneous paste composition by simply heating without adding fine particles and the like, the paste composition obtained particularly at a high solid content is a good one. The present inventors have found that they exhibit thixotropy and have characteristics suitable for screen printing, and have completed the present invention.

That is, the polyimide precursor composition of the present invention comprises bis (4- (3-aminophenoxy) phenyl)
Min aromatic diamine formed containing sulfone 70 mol% or more of <br/> aromatic tetracarboxylic acid component oxygenated solvent as the solvent
Mix and mix aromatic diamine component and aromatic tetracarboxylic acid
A thixotropy coefficient obtained by heat-treating a polyamic acid solution obtained by reacting the components is a polyimide precursor composition of 1.5 or more, more preferably a polyamic acid solution, the following A, B, C3 components It is a polyimide precursor composition as a constituent element. A: benzenetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, terphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride or an aromatic tetracarboxylic acid in which a reactive derivative thereof is 50 mol% or more. carboxylic acid component B: 70 mol% or more is bis (4- (3-aminophenoxy) phenyl) sulfo down, siloxy diamine is 10 mol% or less than 1 mol%, the tetracarboxylic acid component (a) 1 mole of 0.95 to 1.05 mol amount of diamine component C: lactone having a boiling point of 180 ° C. or more and 300 ° C. or less The polyimide precursor composition of the present invention may be used as a paste for screen printing. In consideration of the shape retention of the relief pattern, its solid content concentration is 20% by weight or more, preferably 25% by weight or more. There, the plate pattern 60 wt% from the upper limit of the viscosity range in consideration of filling of the openings or less, preferably 50 wt% or less.

The polyimide precursor composition of the present invention is a polyimide precursor composition comprising the above three components and an unsaturated compound. Of the aromatic tetracarboxylic acid component used in the present invention, preferably 50 mol% or more is benzenetetracarboxylic acid, for example, pyromellitic acid, trifluoromethylbenzenetetracarboxylic acid, bistrifluoromethylbenzenetetracarboxylic acid, difluoro One or two or more selected from reactive derivatives such as biphenyltetracarboxylic acid, terphenyltetracarboxylic acid or benzophenonetetracarboxylic acid such as benzenetetracarboxylic acid or anhydrides and esters thereof. Other tetracarboxylic acids that can be used at less than 50 mol% as the tetracarboxylic acid component include, but are not particularly limited to, hexafluoroisopropylidene diphthalic acid, oxydiphthalic acid, cyclobutanetetracarboxylic acid, bicyclo (2,2,2) oct-7. Examples thereof include reactive derivatives such as -ene-2,3,5,6-tetracarboxylic acid or anhydrides and esters thereof, and two or more of these may be used in combination. If used, a polyimide precursor composition having a uniform thixotropy cannot be obtained by heat treatment.

The diamine component used in the polyimide precursor composition according to the present invention is particularly preferably such that at least 70 mol% of bis (4-
(3-aminophenoxy) phenyl) sulfo Ri emissions at Oh <br/>, particularly preferable 10 mole% or more than 1 mol% is siloxy diamine, as the siloxy diamine,
Although not particularly limited, 1,3-bis (3-aminopropyl) -1,1,2,2-tetramethyldisiloxane,
1,3-bis (3-aminobutyl) -1,1,2,2-
Examples include tetramethyldisiloxane, bis (4-aminophenoxy) dimethylsilane, and 1,3-bis (4-aminophenoxy) tetramethyldisiloxane, and two or more of these can be used in combination.

The amount of siloxydiamine used is preferably 1 to 10 mol% of the diamine component, more preferably 1 to 5 mol% of the diamine component used. 1 diamine component
If the amount is less than 10 mol%, the effect of improving the adhesion is poor, and 10 mol%.
If it exceeds, the heat resistance is lowered without improving the adhesiveness, which is not preferable.

The diamine component which can be used in less than 30 mol% is not particularly limited, but o-, m-, p-phenylenediamine, 2,4-diaminotoluene, 2,5-
Diaminotoluene, 2,4-diaminoxylene, 2,4
-Diaminodulene, dimethyl-4,4'-diaminodiphenyl, dialkyl-4,4'-diaminodiphenyl, dimethoxy-4,4'-diaminodiphenyl, diethoxy-4,4'-diaminodiphenyl, 4,4'- Diaminodiphenylmethane, 4,4′-diaminodiphenylether, 3,4′-diaminodiphenylether,
4,4'-diaminodiphenylsulfone, 3,3'-
Diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone,
1,3-bis (3-aminophenoxy) benzene, 1,
3-bis (4-aminophenoxy) benzene, 1,4-
Bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis (4-
(4-aminophenoxy) phenyl) sulfone, 2,
2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy)
Phenyl) hexafluoropropane, 2,2-bis (4
-(3-aminophenoxy) phenyl) propane, 2,
2-bis (4- (3-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (4-amino-2-trifluoromethylphenoxy) phenyl) hexafluoropropane, 2,2-bis ( 4- (3-amino-5-trifluoromethylphenoxy) phenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 4,4′-bis (4
-Aminophenoxy) octafluorobiphenyl, 2,
2'-bis (trifluoromethyl) diaminodiphenyl, 3,5-diaminobenzotrifluoride, 2,5-
Diaminobenzotrifluoride, 3,3'-bistrifluoromethyl-4,4'-diaminobiphenyl, 3,
3'-bistrifluoromethyl-5,5'-diaminobiphenyl, bis (trifluoromethyl) -4,4'-diaminodiphenyl, bis (fluorinated alkyl) -4,
4'-diaminodiphenyl, dichloro-4,4'-diaminodiphenyl, dibromo-4,4'-diaminodiphenyl, bis (fluorinated alkoxy) -4,4'-diaminodiphenyl, diphenyl-4,4'-diaminodiphenyl 4,4′-bis (4-aminotetrafluorophenoxy) tetrafluorobenzene, 4,4′-bis (4
-Aminotetrafluorophenoxy) octafluorobiphenyl, 4,4'-binaphthylamine, 4,4'-diaminobenzanilide, 4,4'-diamino (N-alkyl) benzanilide and the like, and two or more of these can be used in combination. You can also.

When bis (4- (3-aminophenoxy) phenyl) sulfone is used in an amount of 70 mol% or more, even when the above diamine is used, it is subjected to a heat treatment so as to obtain a paste suitable for screen printing to have thixotropic properties. Can be obtained.

In general, when an aromatic polyamic acid is prepared in an oxygen-containing solvent, for example, γ-butyrolactone, a complex or oligomer precipitates as a solid, and a homogeneous solution cannot be obtained promptly. However, the polyamic acid according to the present invention is excellent in solubility and can quickly give a homogeneous solution without precipitation even in an oxygen-containing solvent such as γ-butyrolactone.

The solvent used in the present invention is an oxygen-containing solvent.
It is preferable that the oxygen-containing solvent has a boiling point of not less than 300 ° C. and not more than 300 ° C.

In a solvent mainly composed of an amide-based solvent such as N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, etc., which are generally used as a solvent for polyimide or its precursor and have a large dissolving power, The polyamic acid according to the present invention merely causes a decrease in viscosity by heat treatment, and does not exhibit the thixotropic property required for screen printing.

Preferred examples of the oxygen-containing solvent include lactones such as γ-butyrolactone, α-methyl-γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, and ε-caprolactone.
In addition, carbonates such as ethylene carbonate and propylene carbonate, esters such as butyl acetate, ethyl cellosolve acetate, butyl cellosolve acetate, ethers such as dibutyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether, methyl isobutyl ketone, cyclohexanone, acetophenone Ketones, alcohols such as butanol, octanol, and ethyl cellosolve, as well as chain or cyclic amide, urea, sulfoxide, sulfone, hydrocarbon, and halogen solvents, polyamic acid solutions, polyimides It can be added in a range that does not affect the stability of the precursor composition.

The choice of solvent is particularly important when a maleimide compound is selected as the unsaturated compound. Because,
The maleimide compound is unstable due to a Michael addition reaction with an aromatic diamine or a polyamic acid even in the absence of a catalyst in an amide solvent, but has a relatively low reactivity in an oxygen-containing solvent such as γ-butyrolactone and is stable. is there. Therefore, it is relatively easy to prepare a polyamic acid solution containing a maleimide compound in an oxygen-containing solvent, and it is stable without gelling during storage.

The unsaturated compound used in the polyimide precursor composition of the present invention is preferably a maleimide compound, an acetylene compound, a vinyl compound or an allyl compound.
Bismaleimide is preferable as the maleimide compound,
Particularly preferred are, for example, 2,2′-bis (4
-Maleimidophenyl) hexafluoropropane, 2,
2'-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane, 2,2'-bis (4-
Fluorinated bismaleimides such as (2-trifluoromethyl-4-maleimidophenoxy) phenyl) hexafluoropropane and 4,4′-bis (4-maleimidophenoxy) octafluorobiphenyl can be exemplified, but other usable bismaleimides For example, 4,
4'-Bismaleimide diphenylmethane, 4,4'-Bismaleimide diphenyl ether, 4,4'-Bismaleimide benzanilide, 2,2'-Bis (4- (4-maleimidophenoxy) phenyl) propane and the like can be mentioned. . As the acetylene compound, for example, THERMID ^™ MC-600, IP-600, IP-610, I
P-630, LR-600, FA-700 (Kanebo
Acetylene-terminal-added polyimide such as NSC Co., Ltd. products). It is also possible to use two or more of the above unsaturated compounds in combination.

The addition of the unsaturated compound in the polyimide precursor composition of the present invention may be carried out by using a substrate material other than metal, for example,
It is particularly effective in improving the adhesiveness to glass, ceramics, organic materials, etc., but in particular, fluorine-containing bismaleimide and acetylene-terminated isoimide oligomer (for example, THERMID ^™ IP-600) having high solubility are increased in concentration,
It is preferable from the viewpoint of film forming property and the like. Further, in the step of desolvation after applying the polyimide precursor composition to the substrate, the non-fluorinated maleimide compound may crystallize and cause a whitening phenomenon of the film, but the fluorinated maleimide compound is a non-fluorinated maleimide compound It has a lower melting point, higher compatibility with polyamic acid, and a higher curing start temperature of the polyimide precursor composition, and is preferable because such a phenomenon does not occur.

In the present invention, the maleimide can also be used as a maleimide prepolymer. As the maleimide prepolymer, bismaleimide alone, bismaleimide-
Bismaleimide prepolymers such as diamines, bismaleimide-biscyanates or bismaleimide-biscyanamides are preferred, and in particular comprise one or more of fluorinated bismaleimides, fluorinated diamines, fluorinated viscyanates, and fluorinated biscyanamides Fluorinated maleimide prepolymers are preferred.

The amount of the unsaturated compound used is preferably in the range of 5 to 30% by weight, more preferably 10 to 20% by weight, based on the total resin solid content of the tetracarboxylic acid component and the diamine component. When the amount is less than 5% by weight, the adhesive effect is poor, and when the amount is more than 30% by weight, the mechanical properties of the formed film are deteriorated without improving the adhesive effect.

Hereinafter, as a method for producing the polyimide precursor composition of the present invention, a case where a maleimide compound is contained will be described. However, when the compound is not used or when the above-mentioned unsaturated compound is used, those skilled in the art can easily prepare the polyimide precursor composition. It is of course possible to make conceivable changes to.

The heat treatment in the method for producing the polyimide precursor composition of the present invention is operationally called cooking, which is similar to the operation used for adjusting the molecular weight, that is, viscosity, and involves mechanical operations such as stirring. 60 ° C or higher without
By heating at 50 ° C. or lower for a predetermined time, the polyimide precursor composition containing the oxygen-containing solvent becomes translucent or opaque, and particularly when the solid content concentration is 25% by weight or more, a homogeneous paste having thixotropic properties. This is an extremely simple method of forming a liquid composition.

That is, in general, when producing a polyamic acid solution having a high concentration and a high viscosity, a special device is required for a device for sequentially adding components, a stirrer for a reactor, and the like.
Further, it is not always easy to uniformly knead and disperse an organic or inorganic powder for imparting thixotropy to a viscous polyamic acid solution once withdrawn from the reactor or once prepared, and particularly for a small variety of various kinds. In the production, there were difficulties in the production such as complicated washing and drying of the reactor every time the product was changed, but such a problem hardly occurs in the method of the present invention.

The conditions of the heat treatment vary depending on the composition of the polyamic acid solution, the solid content concentration, the volume, and the viscoelastic properties of the paste required for the polyimide precursor composition to be produced, and are determined by the heat treatment temperature and time. , 60 ° C ~
It is desirable to heat-treat at 150 ° C, more preferably 80 ° C to 120 ° C, for about 1 to 48 hours. When the temperature is 60 ° C. or lower, the conversion rate is low, and when the temperature is 150 ° C. or higher, the conversion rate is too fast. Therefore, it is not easy to adjust the viscoelastic properties showing appropriate screen printability, and the time or temperature of the heat treatment is insufficient. In this case, the separation of the paste from the plate and the shape retention of the relief pattern are lacking. Undesirably occurs.

In some cases, the heat treatment includes cooling as a post-treatment of the heating operation and standing at around room temperature.
That is, depending on the operating conditions such as the diamine component, the tetracarboxylic acid component, the solvent, and / or the mixing and heating, the translucent or opaque solution may not occur immediately by simply heating but may occur after a certain period of time. It is.
Usually, cooling need not be particularly controlled, and natural cooling may be performed. However, in some cases, it is preferable to adjust the cooling rate. The term "around room temperature" means that there is no particular need to be a limited temperature, and usually a temperature of about 0 to 50 ° C may be sufficient. The standing is performed until the appearance of the polyamic acid solution no longer changes.
It is performed over a period of time to several tens of days, but since there is no need to add operations such as stirring and shaking, there is no difference from ordinary storage.

It is not clear why the heat treatment of the polyamic acid of the present invention makes it translucent or opaque and develops thixotropic properties. However, the polyamic acid solution is partially dehydrated and ring-closed to form polyamic acid imide.
It is presumed that the interaction between the polyamidoimide chains and / or between the polyamidoimide chains and the solvent resulted in a microscopic structure.

The polyamic acid solution to be subjected to the heat treatment can be prepared by a conventionally known method. At this time, the diamine component and the tetracarboxylic acid component are charged into the reactor in advance, and then the solvent is added.When the solvent is added, the viscosity is partially increased due to rapid polymerization before being uniformly dissolved. However, in order to obtain a uniform polyamic acid solution, tetracarboxylic acid is usually added to a solution in which a diamine component is dissolved because there is a problem that a solid block partially forms and the solid block does not easily dissolve because of forming a complex. A method of sequentially adding the components or a method of sequentially adding the diamine component to a solution in which the tetracarboxylic acid component is dissolved is preferable.

Generally, a method of sequentially adding a tetracarboxylic acid component to a solution in which a diamine component is dissolved has been adopted because the solubility of a tetracarboxylic acid anhydride generally used as a tetracarboxylic acid component is low. You.

When a maleimide compound is added, the diamine, particularly a siloxydiamine having a strong nucleophilicity, and the maleimide compound easily cause a Michael addition reaction to cause precipitation or gelation of an insoluble solid. In consideration of stability, it is desirable that the maleimide compound be mixed and dissolved with the tetracarboxylic acid component. However, if each component is mixed shortly after addition,
There is no particular limitation on the order in which the maleimide compound is mixed with the other components, and a method of mixing the maleimide compound with the tetracarboxylic acid component oligomerized with the diamine component, or after adding the tetracarboxylic anhydride to the diamine solution Any method such as a method of further mixing and dissolving the maleimide compound and a method of mixing and dissolving the maleimide compound and the diamine together can be adopted.

Preferably used for screen printing, 20
In the preparation of a polyamic acid solution having a high solid content of not less than 1% by weight, uniform stirring and mixing is not easy because the solution viscosity is too high. However, there is a problem that bubbles are caught by stirring and mixing even if a homogeneous product is obtained.

In order to solve this problem, solutions in which a tetracarboxylic acid component and a diamine component are mixed and dissolved are prepared in advance, and the mixed solution obtained when each of the component solutions is weighed in a container so as to be substantially equivalent. Observation of the behavior revealed that high-concentration tetracarboxylic acid solutions, especially oligomerized tetracarboxylic acid solutions obtained by adding diamine to tetracarboxylic acid and diamine solutions, were mixed quickly due to the viscosity difference between these solutions. However, two-phase separation was observed with a low solution viscosity, and it was found that when this was stirred by a stirrer equipped with stirring blades, the biting of bubbles was remarkable. Therefore, it has been found that when the mixed solution separated into the two layers is rapidly and uniformly mixed by a revolving centrifugal method and then polymerized, a high-viscosity, homogeneous solution free of bubble entrapment can be easily obtained. Was.

The solution of the tetracarboxylic acid component and the diamine component used in the present invention has a much lower solution viscosity than the polyamic acid solution obtained by mixing and aging them. By performing the filter treatment at the stage of (1), a polyamic acid having an extremely small content of particles, which is a problem in forming a thin film, can be obtained, which is preferable.

Also, a reaction product such as a partial anhydride, ester or oligomer of tetracarboxylic acid obtained from tetracarboxylic anhydride and less than 0.5 equivalent of water, alcohol or diamine can be used as a tetracarboxylic acid component. Is useful for adjusting the degree of polymerization and viscosity in a high-concentration low-viscosity solution of a tetracarboxylic acid component or a high-concentration solution of a polyamic acid solution. However, a reaction product solution with a diamine of 0.5 equivalent or more is not preferable because it is not easy to handle, such as poor quantitativeness of pumping due to an increase in viscosity when the concentration is high.

For the purpose of adjusting the degree of polymerization and viscosity at a predetermined concentration, it is convenient to mix a solvent prepared by adding water or alcohol. The degree of polymerization of the oligomerized tetracarboxylic acid component can also be adjusted by cooking at 50 to 100 ° C. for about 1 hour. At this time, when an unsaturated compound is present, the unsaturated compound is prepolymerized. Although the degree of polymerization increases, there is no particular problem.

The alcohol that can be used for the purpose of forming the ester is not particularly limited as long as it is usually used as an organic solvent. For example, methanol, ethanol, isopropanol, methyl cellosolve, ethyl cellosolve, diethylene glycol monomethyl Ether and the like can be exemplified.

The production of the polyimide precursor composition of the present invention is preferably carried out in a dry atmosphere such as nitrogen, hydrogen, helium or dry air. However, when an oxygen-containing solvent such as γ-butyrolactone is used, the production is relatively low. The effect of target moisture is small.

The polyimide precursor composition of the present invention produced in this manner is manufactured by RHEOLAB MC manufactured by Physica.
20 (cone / plate method or cylinder method, 22
° C. Hereinafter, the same conditions unless otherwise noted. ), When the steady shear rate is 20 sec ^-1 and 0.5 sec.
The difference in the apparent viscosities shown at ec ^-1 is large and shows remarkable thixotropy.

As a value representing the thixotropy, a thixotropy coefficient [η _0.5 / η ₂₀ ] (when the steady-state shear rate is 0.
The apparent viscosity [eta _0.5] in 5 sec ^-1, the steady shear rate and divided by the apparent viscosity [eta _20] in 20sec ^-1. This value is preferably 1.5 or more for good screen printing characteristics.
-1000 is more preferable, and 1.5-250 is still more preferable.

In general, it is known that in a substance exhibiting thixotropic properties, the measured viscosity reflects the history up to the viscosity measurement.
It is desirable that the thixotropy coefficient obtained based on the ultimate viscosity lowered with the application of shear stress is sufficiently large. For example, as described in detail in the embodiment, 20 sec
It is preferable to have a thixotropy coefficient of 1.5 or more also based on the ultimate viscosity after application of a shear stress of ⁻¹ and reduced.

The novel thixotropic polyimide precursor composition of the present invention has a thickness of 0.1 after firing.
~ 100μm relief pattern can be formed,
By selecting the monomer to be used, setting the preparation conditions of the tetracarboxylic acid component, setting the solid content, and setting the heat treatment conditions, it is possible to adjust the viscoelastic properties appropriate for the plate shape to be used and the desired film thickness in a wide range. .

Preferred Polyimide Precursor Composition of the Invention
The range of viscoelastic properties is 0.5 sec ^-1Apparent viscosity
Degree [η_0.5Is approximately 150 poise or more and 25,000 po
Is less than 20 seconds^-1Apparent viscosity [η
₂₀] Is approximately 10 poise to 5000 poise
You. [Η_0.5] Is 150 poise or [η₂₀] Is 10 points
If the size is smaller than the size, the shape retention of the pattern is inferior and [η_0.5]
Is 25,000 poise or [η₂₀] Got 5,000 poise
If it exceeds, the filling property is inferior and is not preferred.

By selecting a paste having this viscoelastic characteristic range, from a thin film to a thick film, under appropriate screen printing conditions, the filling property into the plate pattern opening, which is excellent in practicality, and the shape of the formed relief pattern Retention is obtained.

The relief pattern of the polyimide precursor composition of the present invention formed by screen printing is converted into a polyimide relief pattern by baking after removing the solvent, and the polyimide composition is excellent in coating adhesion, mechanical properties and the like. A coated body can be obtained.

Desolvation conditions are, depending on the coating film thickness, in the range of 50 to 200 ° C. for 1 to 150 minutes in an inert atmosphere such as air or nitrogen or hydrogen. 10
In the case of a thin film of less than μm, there is no problem even in a short period of time of not less than 30 minutes at a high temperature of not less than 100 ° C. The above-mentioned low-temperature long-time treatment is preferable.

The firing conditions are 250 to 450 ° C., preferably 300 to 400 ° C., and more preferably 320 to 380 ° C., depending on the coating film thickness. Also,
The time required for baking depends on the coating thickness, but 10
Minutes to 5 hours, preferably 20 minutes to 3 hours, more preferably 30 minutes to 2 hours. Since the calcination is a process of condensing the polyamic acid into a polyimide, the above-mentioned 250 is used.
If the temperature exceeds 10 ° C. or 10 minutes, imidization does not proceed sufficiently, and the intrinsic physical properties of the polyimide such as the mechanical strength and heat resistance of the formed coating film are undesirably deteriorated. On the other hand, when the temperature exceeds 450 ° C. or 5 hours, the decomposition of polyimide occurs and the mechanical strength decreases, which is not preferable.

The substrate on which the polyimide composition of the present invention is coated may be copper, aluminum, silicon or an alloy thereof or a metal such as stainless steel, alumina, glass, borosilicate glass, quartz, zirconia, mullite, nitride, or the like. Ceramic materials such as silicon, and semiconductor materials such as barium titanate, lithium niobate, tantalum niobate, gallium arsenide, and indium phosphide can be used without limitation. In addition, polyimide,
Aromatic polyamide, polyphenylene, polyxylylene,
It is also possible to coat a substrate coated with a heat-resistant polymer compound such as polyphenylene oxide, polysulfone, polyamide imide, polyester imide, polybenzimidazole, polyquinazolinedione, and polybenzoxazinone.

Non-limiting examples of more specific applications of the polyimide composition of the present invention include monolithic ICs on a substrate made of silicon wafer, gallium arsenide, etc., such as DRAM, SRAM, CPU, etc. Devices such as hybrid ICs, thermal heads, image sensors, multi-chip high-density mounting boards formed on substrates, flexible wiring boards, various wiring boards such as rigid wiring boards, interlayer insulating films or surface protection, α-ray shielding, etc. Although it can be used as a protective film having various purposes, it is not limited to these applications.

Hereinafter, the present invention will be described in detail with reference to Examples, but the embodiments are not limited thereto.

[0053]

【Example】

Example 1 386.9 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
Of bis (4- (3-aminophenoxy) phenylsulfone (hereinafter referred to as "BAPS"; 894.5 mmol)
l) and 507.3 g of pyromellitic dianhydride (hereinafter referred to as “PMDA” 2325 mmol) were added, 1522 g of γ-butyrolactone was added, and 1
After stirring for an hour, an oligomer solution of tetracarboxylic anhydride was prepared. Similarly, 604.7 g of BAPS (1398)
mmol) and 17.66 g of 1,3-bis (3-aminopropyl) tetramethyldisiloxane (hereinafter referred to as “TMD
S ". 71.6 mmol) and 1060 g
(Gamma) -butyrolactone was added and dissolved by stirring at room temperature to prepare a diamine component solution.

After clarifying the relationship between the set flow rate and set time of the precision metering pump and the amount of liquid supply and confirming the quantitativeness, each of the prepared tetracarboxylic anhydride oligomer solution and diamine component solution was 43. 1ml /
1.34 min and 53.3 ml / min at a flow rate of min
Was set to 0.77 minutes, and approximately equimolar amounts of the tetracarboxylic acid component and the diamine component were metered into a 150 ml polyethylene bottle and sealed. At this stage, the two liquids were phase-separated, and no increase in viscosity, that is, progress of polymerization was observed.

The rotation and centrifugal mixer (Co., Ltd.)
The mixture was rapidly mixed and polymerized by SNB-350 (manufactured by IKS) to obtain a transparent viscous polyamic acid solution having a solid content of 37.0% by weight.

The same operation was carried out on the same tetracarboxylic anhydride oligomer solution and diamine component solution.
After repeating 0 times, the metered injection amounts of the tetracarboxylic acid oligomer solution and the diamine component solution were 71.538 g (42.375 mmol) as the average value of each.
And the molar ratio (tetracarboxylic acid component / diamine component) was 1.000 ± 0.003 at 48.514 g (42.388 mmol), and the apparent viscosity of the obtained polyamic acid solution measured at 1 Hz after 24 hours was measured. The value measured by the cone / plate method at 22 ° C. with RHEOLMC 20 manufactured by Physica Co., unless otherwise indicated, measurement at 1 Hz.
It was a homogenous solution with 800 ± 500 poise and no biting of bubbles. 0.5 sec ^-1 and 20 sec of this solution
There was almost no difference in the apparent viscosity at c ⁻¹ , and the thixotropic coefficient was 1.2.

When 30 bottles of the polyamic acid solution prepared here were placed in an oven at 90 ° C. and heated for 7 hours, an orange-brown transparent polyimide precursor composition solution was obtained. At that time, the apparent viscosity was 200 poise and the thixotropy coefficient was 1. However, after natural cooling, the solution was allowed to stand at room temperature and was converted into a brown paste one week later.
The apparent viscosities at 5 sec ^-1 and 20 sec ^-1 were 3800 ± 200 poise and 600 ± 30 poise, respectively, and the thixotropic coefficient was 6.3. Shear stress is applied at 20 sec ^-1 for 1 minute, and the ultimate value of the decreasing viscosity is 0.
1000 ± 5 at 5 sec ^-1 and 20 sec ^-1 respectively
The average thixotropy coefficient at 0 poise and 500 ± 30 poise was approximately 2.0.

As a screen printability evaluation of this paste, 100 μm obtained by punching five 0.2 mm × 20.0 mm strip-shaped patterns at 5 mm intervals in the squeegee moving direction.
When 25 sheets were continuously printed on a glass substrate using a stainless steel plate having a thickness of m, a good relief pattern was obtained without any defects such as missing, chipping, stringing, and bleeding. The glass substrate was placed in an oven, kept at 70 ° C. for 1 hour, then heated to 350 ° C. for 2 hours, and then fired for 1 hour to have a film thickness of 35 to 37 μm. The difference between the pattern size of the plate and that of the formed glass pattern was ± 50 for both the glass substrate patterns both vertically and horizontally.
μm or less, and the difference between the relief surface size and the substrate surface size is 500
It was within μm, and the shape retention of the pattern was also good.

Silicon, alumina and polyimide coating Each substrate of silicon was coated with the polyimide precursor composition paste prepared above by a doctor blade method so as to have a thickness of about 5 μm after firing, and then heated at 350 ° C. for 1 hour.
After firing for about 5 hours, a substrate coated with a polyimide composition film of about 5 μm was obtained. JISK 100 1mm grids
Prepared according to -5400, 121 ° C, 2.2 kg / c
A pressure cooker test was conducted for 100 hours under the conditions of m ^{2, and} the adhesion was evaluated by a tape peel test after the treatment. As a result, no peeling was observed on any of the substrates, and good adhesion was exhibited.

Example 2 38.57 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube.
BAPS (89.19 mmol), 39.41 g of P
MDA (180.7 mmol), 17.68 g of 2,
22′-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane (hereinafter referred to as “OFM”; 15 wt% of the total solid content) was charged and 221.6.
g of γ-butyrolactone and stirred at 60 ° C. for 1 hour,
An oligomer solution of tetracarboxylic anhydride was prepared.
Similarly, 111.0 g of BAPS (256.7 mmol
l) 4.081 g of TMDS (16.4 mmol),
266.6 g of γ-butyrolactone was added and dissolved by stirring at room temperature to prepare a diamine component solution. 317.3 g of tetracarboxylic anhydride oligomer solution and diamine solution 1
27.5 g was weighed into a container with a syringe and centrifuged with stirring under the same apparatus and conditions as in Example 1 to obtain a polyamic acid solution having a solid content of 30 wt% and an apparent viscosity of 4000 poise.

Heat treatment in an oven at 110 ° C. for 3 hours
As a result, a brown paste was obtained for 0.5 sec.
^-1And 20 sec^-1Apparent viscosity at 550 each
The thixotropic coefficient is 1 at 0 poise and 380 poise.
4.5. 20 sec ^-1With shear stress for 1 minute
The value of the viscosity that decreases is 0.5 sec.^-1And 2
0 sec^-1At 770 poise and 160 poi respectively
And the thixotropic coefficient was 4.8.

When this paste was evaluated for screen printability in the same manner as in Example 1, no defect such as omission, chipping, stringing or bleeding was observed, and a good relief pattern was obtained. Similarly, the film subjected to the baking treatment had a film thickness of 30 to 32 μm, and the pattern shape retention was as good as in Example 1. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Example 3 19.24 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (44.50 mmol) and 14.26 g of 2,2'-bis (trifluoromethyl) -4,4'diaminodiphenyl (hereinafter referred to as "ABL").
mmol) and 38.81 g of PMDA (177.9 mm
ol) and 16.62 g of OFM (15 wt% based on polyamic acid) were added, 207.1 g of γ-butyrolactone was added, and the mixture was stirred at 60 ° C. for 1 hour to prepare a tetracarboxylic anhydride oligomer solution. Similarly, 111.0 g
BAPS (256.7 mmol), 4.081 g T
MDS (16.4 mmol) and 266.6 g of γ-butyrolactone were added and dissolved by stirring at room temperature to prepare a diamine component solution. 296.1 g of an oligomer solution of tetracarboxylic anhydride and 123.9 g of a diamine solution were weighed into a container with a syringe and mixed by centrifugal stirring to obtain a polyamic acid solution having a solid content of 30 wt% and an apparent viscosity of 4,700 poise.

A heat treatment was performed in an oven at 100 ° C. for 8 hours.
As a result, a brown paste was obtained for 0.5 sec.
^-1And 20 sec^-1Apparent viscosity is 360
Thixotropic coefficient is 1 at 0 poise and 220 poise
6.4. 20 sec ^-1With shear stress for 1 minute
The value of the viscosity that decreases is 0.5 sec.^-1And 2
0 sec^-1850 poise and 110 poi respectively
And the thixotropic coefficient was 7.7.

When this paste was evaluated for screen printability in the same manner as in Example 1, no defect such as missing, chipping, stringing or bleeding was observed, and a good relief pattern was obtained. Similarly, the film subjected to the baking treatment had a film thickness of 30 to 32 μm, and the pattern shape retention was as good as in Example 1. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Comparative Example 1 33.83 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (78.22 mmol), 44.36 g of P
MDA (203.4 mmol) and 158.6 g of γ-butyrolactone were added, and the mixture was stirred at 60 ° C. for 1 hour to prepare a tetracarboxylic anhydride oligomer solution. Similarly 1
1.88 g of BAPS (27.46 mmol), 29.
23 g of ABL (91.27 mmol), 1.152 g
Of TMDS (6.08 mmol) and 86.5 g of γ-butyrolactone were added thereto and dissolved by stirring at room temperature to prepare a diamine component solution. 84.1 g of an oligomer solution of tetracarboxylic anhydride and 46.0 g of a diamine solution were weighed into a container with a syringe, and mixed by centrifugation with stirring.
A polyamic acid solution having 3 wt% and an apparent viscosity of 10400 poise was obtained.

Heat treatment was performed in a 90 ° C. oven for 15 hours.
As a result, a brown transparent polyimide precursor composition solution
Obtained. The apparent viscosity at that time was 90 poise and thixot
The ropy coefficient was 1, but it was left at room temperature.
One week later, it turned into a brownish paste.
5 sec^-1And 20 sec^-1The apparent viscosity at
Thixotropic person at 270 poise and 190 poise
The number was 1.4. 20 sec^-1Shear stress for 1 minute
The ultimate value of the multiplied and reduced viscosity is 0.5 sec. ^-1and
20 sec^-1At 210 poise and 160 poise respectively.
And the thixotropic coefficient was 1.3.

When the screen printability of this paste was evaluated in the same manner as in Example 1, no defect such as omission or chipping was observed. However, stringing was observed between the plate and the glass substrate.
Bleeding occurred, and a good relief pattern was not obtained. A film obtained by baking it in the same manner as in Example 1 has a film thickness of 30.
However, the pattern shape was not sufficiently maintained. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Example 4 8.243 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (19.06 mmol) and 8.076 g of 3,3′-diaminodiphenylsulfone (hereinafter referred to as “D
DS ". 32.53 mmol) and 29.26 g of PMDA (134.1 mmol) were charged and 84.7 g
Of γ-butyrolactone was added and stirred at 60 ° C. for 1 hour to prepare a tetracarboxylic anhydride oligomer solution. Similarly, 33.96 g of BAPS ( 78.52 mmol),
1.005 g of TMDS (4.04 mmol), 64.
9 g of γ-butyrolactone was added and dissolved by stirring at room temperature to prepare a diamine component solution. 130.2 g of an oligomer solution of tetracarboxylic anhydride and 99.8 g of a diamine solution
Was weighed into a container with a syringe, and mixed by centrifugal stirring to obtain a polyamic acid solution having a solid content of 35 wt% and an apparent viscosity of 5,900 poise.

When heat treatment was performed in an oven at 110 ° C. for 7 hours, a brown transparent polyimide precursor composition solution was obtained. Although time thixotropy coefficient apparent viscosity of 40 poise was 1 thereof, apparent at 0.5 sec ^-1 and 20sec ^-1 converted into brown paste at room temperature about 24 hours after was allowed to stand as it is The viscosities were 830 poise and 170 poise, respectively, and the thixotropic coefficient was 4.9. 20sec ^-1 multiplied by 1 minute shear stress, the achieved value of viscosity to decrease, at 0.5 sec ^-1 and 20sec ^-1, respectively 390 poise and 16
At 0 poise, the thixotropic coefficient was 2.4.

The paste was evaluated for screen printability in the same manner as in Example 1. As a result, a good relief pattern was obtained without any defects such as missing, chipping, stringing, and bleeding. Similarly, the film subjected to the baking treatment had a film thickness of 33 to 35 μm, and the pattern shape retention was as good as in Example 1. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Example 5 12.96 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (29.97 mmol), 16.99 g P
MDA (77.91 mmol) was charged, 44.7 g of γ-butyrolactone was added, and the mixture was stirred at 60 ° C. for 1 hour to prepare a tetracarboxylic anhydride oligomer solution. Similarly, 25.38 g of BAPS (58.69 mmol),
0.451 g of TMDS (1.82 mmol), 36.
9 g of γ-butyrolactone was added and dissolved by stirring at room temperature to prepare a diamine component solution. Separately, 10.04 g of THERMID IP-610 was dissolved in 30.2 g of γ-butyrolactone to prepare a THERMID solution. 74.6 g of tetracarboxylic anhydride oligomer solution and diamine solution 4
9.9 g and 30.3 g of the thermid solution were weighed into a container with a syringe and mixed by centrifugal stirring under the same apparatus and conditions as in Example 1 to obtain a polyamic acid solution having a solids concentration of 37 wt% and exhibiting a rubbery state.

A heat treatment was performed for 9 hours in an oven at 90 ° C., and the mixture was allowed to stand at room temperature for 1 week. The apparent viscosity was 30 poise and the thixotropic coefficient was 1, but the heat treatment was further performed in an oven at 110 ° C. for 3 hours. When performed, the paste was converted to a brownish paste, and 0.5 sec ^-1 and 20 sec.
The apparent viscosities at sec ^-1 were 4200 poise and 350 poise, respectively, and the thixotropic coefficient was 12.1. 20sec ^-1 multiplied by 1 minute shear stress, reaches values of reduction for viscosity at 0.5 sec ^-1 and 20sec ^-1,
The thixotropy coefficient was 2.3 at 680 poise and 290 poise, respectively.

The paste was evaluated for screen printability in the same manner as in Example 1. As a result, a good relief pattern was obtained without any defects such as missing, chipping, stringing, and bleeding. Similarly, the film subjected to the baking treatment had a film thickness of 35 to 37 μm, and the pattern shape retention was as good as in Example 1. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Example 6 10.61 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (24.53 mmol), 10.44 g of P
MDA (47.84 mmol), 4.690 g of biphenyltetracarboxylic dianhydride (15.94 mmol)
Was added, and 60.1 g of γ-butyrolactone was added thereto.
The mixture was stirred at 1 ° C. for 1 hour to prepare a tetracarboxylic anhydride oligomer solution. Similarly, 16.15 g of BAPS (3
7.34 mmol), 0.476 g of TMDS (1.9
1mmol) and 38.9 g of γ-butyrolactone were added and dissolved by stirring at room temperature to prepare a diamine component solution. 85.8 g of an oligomer solution of tetracarboxylic anhydride and 55.5 g of a diamine solution were weighed into a container with a syringe, and mixed by centrifugal stirring under the same apparatus and conditions as in Example 1. The solid content was 30 wt%, and the apparent viscosity was 1300. A poise polyamic acid solution was obtained.

Heat treatment in an oven at 110 ° C. for 23 hours gave a brown transparent polyimide precursor composition solution. Apparent in apparent viscosity at that time is the thixotropic factor of 50 poise was 1, as it is converted to brown paste after about 1 month was allowed to stand at room temperature for 0.5 sec ^-1 and 20sec ^-1 The viscosities were 3600 poise and 210 poise, respectively, and the thixotropic coefficient was 17.1. Shear stress is applied for 1 minute at 20 sec ⁻¹ , and the ultimate value of the decreasing viscosity is 0.5 sec.
^{At -1} and 20 sec ^-1 , the thixotropic coefficient was 2.2 at 260 and 120 poise, respectively.

When this paste was evaluated for screen printability in the same manner as in Example 1, no defect such as missing, chipping, stringing, or bleeding was observed, and a good relief pattern was obtained. Similarly, the film subjected to the baking treatment had a film thickness of 30 to 32 μm, and the pattern shape retention was as good as in Example 1. When the same pressure cooker test as in Example 1 was performed, no peeling was observed.

Comparative Example 2 33.50 g in a glass four-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube.
BAPS (77.46 mmol), 43.92 g of P
MDA (201.3 mmol) was charged and 180.4 g
Of N-methylpyrrolidone and stirred at 60 ° C. for 1 hour,
An oligomer solution of tetracarboxylic anhydride was prepared.
Similarly, 64.56 g of BAPS (149.3 mmo)
l) 1.901 g TMDS (7.65 mmol),
155.1 g of N-methylpyrrolidone was added and dissolved by stirring at room temperature to prepare a diamine component solution. 257.8 g of the tetracarboxylic anhydride oligomer solution and 175.0 g of the diamine solution were weighed into a container with a syringe, and mixed by centrifugal stirring under the same apparatus and conditions as in Example 1. The solid content was 30 wt%, and the apparent viscosity was 280. A poise polyamic acid solution was obtained.

When a heat treatment was performed in an oven at 90 ° C. for 15 hours, an orange or brown transparent polyimide precursor composition solution was obtained. At that time, the apparent viscosity was 6 poises, the thixotropy coefficient was 1, and 25 at room temperature.
After standing for one day, the viscosity increased to 94 poise, but the thixotropic coefficient remained at one.

Since the obtained solution did not show the thixotropy required for screen printing, a test for evaluating the screen printability was not conducted.

[0081]

As described in Examples, the polyimide precursor composition of the present invention exhibits a favorable screen printability, and exhibits excellent adhesion and the like when a polyimide film is formed by firing. Since it has heat resistance, heat resistance, low moisture absorption, low dielectric constant, mechanical strength, chemical stability etc. required as a polyimide composition for screen printing used in electronics, electricity, optics, precision industry, etc. The polyimide precursor composition is useful, and as is apparent from the examples, has a remarkable effect that it can be produced by an extremely simple apparatus and operation.

──────────────────────────────────────────────────の Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C08G 73/10 C08L 79/08 C09D 179/08 B41M 1/12 C09D 11/10 CA (STN) REGISTRY (STN )

Claims (12)

(57) [Claims] 1. A bis (4- (3-aminophenoxy) phenyl) soluble aromatic diamine growth minutes lactones aromatic tetracarboxylic acid component comprising sulfone 70 mol% or more
A mixture of the aromatic diamine component and the aromatic tetraca
A polyimide precursor composition having a thixotropy coefficient of 1.5 or more obtained by heat-treating a polyamic acid solution obtained by reacting a rubonic acid component . (2) bis (4- (3-aminophenoxy) phenyl
Aromatic diamine containing at least 70 mol% of phenyl) sulfone
Component, aromatic tetracarboxylic acid component and unsaturated compound
Lactones are mixed as a solvent, and aromatic diamine component and
The polyimide precursor composition according to claim 1, which has a thixotropic property obtained by heat-treating a polyamic acid solution obtained by reacting an aromatic tetracarboxylic acid component with an unsaturated compound . 3. A thixotropic factor polyimide precursor composition according to any one of claims 1 to 2, characterized in that it is 1.5 to 250. 4. The aromatic tetracarboxylic acid component is benzenetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, terphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride or a reactivity thereof. any of claims 1 to 3, characterized in that it consists of other tetracarboxylic dianhydride and 50 mol% or more of the derivatives or less than 50 mole percent of a reactive derivative thereof
The polyimide precursor composition of crab according. 5. The method according to claim 1, wherein the aromatic diamine component is bis (4- (3
- to claim 1, characterized in aminophenoxy) phenyl) sulfo 10 mol% of 70 mol% or more siloxy diamine compound of emissions and to consist of other diamine
5. The polyimide precursor composition according to any one of 4 . 6. A solvent, boiling point of lactones is 300 ° C. or less 180 ° C. or higher, according to claim 1, wherein less than 80% by weight of the polyimide precursor composition
The polyimide precursor composition according to any one of the above. 7. The unsaturated compound is a maleimide compound, an acetylene compound, a vinyl compound, or an allyl compound, wherein the unsaturated compound accounts for 5 to 30% by weight of the total weight of the aromatic tetracarboxylic acid component and the aromatic diamine component. The polyimide precursor composition according to claim 2, wherein 8. bis (4- (3-aminophenoxy) phenyl) soluble aromatic diamine growth minutes aromatic tetracarboxylic acid components amount lactones containing sulfone 70 mol% or more
A mixture of the aromatic diamine component and the aromatic tetraca
The thixotropy coefficient obtained by heat-treating the polyamic acid solution obtained by reacting the rubonic acid component is 1.5.
The method for producing a polyimide precursor composition described above. 9. The method for producing a polyimide precursor composition according to claim 8, wherein the heat treatment is performed at 60 to 150 ° C. 10. A polyimide composition obtained by applying the polyimide precursor composition according to claim 1 to a substrate and firing the composition. 11. A screen printing ink comprising the polyimide precursor composition according to claim 1. 12. A screen printing method using the screen printing ink according to claim 11. Description: