JP2597214B2 - Polyimide siloxane composition and film for coating film formation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a tetracarboxylic acid component containing 2,3,3 ', 4'-biphenyltetracarboxylic acid or its dianhydride as a main component. 60-75 mol% of diaminopolysiloxane
A special polyimide siloxane having solubility, adhesion, heat resistance, and non-curl property obtained by polymerizing and imidizing a diamine component comprising 25 to 40 mol% of an aromatic diamine is used in a specific organic solvent. A solution composition (a printing ink, a printing ink, or the like) that is capable of forming a protective film on a flexible wiring board by screen printing or the like, which is uniformly dissolved.
Coating varnish) and a film obtained by drying by heating.

[Description of Prior Art]

The use of an aromatic polyimide or the like as an electrically insulating protective film has already been widely known in applications such as an insulating film for a solid-state device, a passivation film, a semiconductor integrated circuit, and an interlayer insulating film such as a flexible wiring board. ing. However, in general, since aromatic polyimide is hardly dissolved in an organic solvent, it is used as a solution of a precursor of aromatic polyimide (aromatic polyamic acid) to form a coating film, and then drying and imidization are performed. It is necessary to form a protective film of aromatic polyimide by performing heat treatment at a considerably high temperature for a long time, and there is a problem that the electric or electronic member to be protected is thermally deteriorated.

On the other hand, as an aromatic polyimide soluble in an organic solvent, for example, a polyimide as described in JP-B-57-41491 is known, and the polyimide is a silicon wafer, a glass plate, a flexible substrate, or the like. Since the adhesion to the substrate (adhesion) was not sufficient, it was necessary to take a method such as treating the substrate or the like in advance with an adhesion promoter.

In order to solve the above-mentioned problems, a precursor of polyimidesiloxane using diaminopolysilicon as a diamine component is disclosed in, for example, JP-A-57-143328,
Although disclosed in JP-A-58-13631, these polyimidesiloxane precursors have a disadvantage that the coating film must be treated at a high temperature for imidization of the polymer.

Also, JP-A-61-118424 and JP-A-61-207438
JP-A-63-225629 and JP-A-1-121325 disclose soluble polyimide siloxanes. However, each of these polyimide siloxanes has several stages in its production process, has a production problem that it takes a long time to produce, does not contain any aromatic diamine as an amine component, and has low heat resistance. Problem,
There is a problem that the solubility in various organic solvents is not always sufficient, or there is a problem that the flexible substrate is largely curled when an organic solvent solution of these polyimidesiloxanes is applied on a flexible copper-clad substrate and dried. Was.

[Problems to be solved]

An object of the present invention is to provide a polyimide siloxane solution composition having high solubility in an organic solvent, necessary heat resistance, and non-curlness when a protective film is formed, and which can be easily produced. And a film which is a cured product thereof.

[Means to solve the problem]

The first invention of the present application relates to 2,3,3 ', 4'-biphenyltetracarboxylic acid, its acid ester or its acid dianhydride.
An aromatic tetracarboxylic acid component containing up to 100 mol%;
The following (a) and (b) obtained by polymerizing and imidizing a diamine component consisting of 60 to 75 mol% of diaminopolysiloxane and 25 to 40 mol% of a polycyclic aromatic diamine having 2 to 4 benzene rings. ) And a logarithmic viscosity of 0.05 to 3 (0.5 g / 100 ml N
-Methyl-2-pyrrolidone, 30 ° C.) in an organic solvent having a boiling point of 140 to 280 ° C. in an amount of 5 to 50% by weight.
(The polymer concentration in the solution), and that there is substantially no warpage in the warp test measured by forming a protective film of polyimidesiloxane on the aromatic polyimide film. The present invention relates to a polyimide siloxane composition for forming a low curl coating film.

(A) 60-75 mol% In (a), in a total of 100 mol% of (1) and (2),
(1) is 80 to 100 mol%, and (2) is 0 to 20 mol%.

(B) 25-40 mol% In (b), a total of 100 mol% of (3) and (4)
(3) is 80 to 100 mol%, and (4) is 0 to 20 mol%.

In the above formula, X is R ₁ represents a plurality of methylene groups having 2 to 6 carbon atoms or a phenylene group, R ₂ independently represents an alkyl group or a phenyl group having 1 to 3 carbon atoms, l is an integer of 3 to 30 Show, Y
Represents a divalent organic residue.

Further, the second invention of the present application is to apply the polyimide siloxane composition for forming a low-curl coating film to a substrate,
It relates to a film obtained by drying by heating.

The polyimidesiloxane represented by the above general formula in the present invention includes, for example, phenol solvents, amide solvents (pyrrolidone solvents, formamide solvents, acetamide solvents, etc.), oxane solvents (dioxane, trioxane, etc.), glyme solvents (Eg, methyl diglyme, methyl triglyme) having sufficient solubility in an organic polar solvent and a relatively low viscosity polyimide siloxane solution (for coating) from the polyimide siloxane and the organic polar solvent. Varnish) can be easily prepared.

Further, the polyimide siloxane according to the present invention does not substantially cause curling when the solution composition is coated on a substrate such as a silicon wafer or a flexible wiring substrate and dried to form a protective film. The protective film has excellent adhesion to each of the above-mentioned substrates, and it is not necessary to pre-treat the substrate with an adhesion promoter such as a silane coupling agent beforehand.For example, passivation films for ICs and LSIs Alternatively, the protective film can be formed for applications such as a junction coat of a diode without performing the above pretreatment.

In the composition of the present invention, the organic solvent has a boiling point of
180 ° C. or higher, especially an organic solvent of 200 ° C. or higher (for example,
When methyltriglyme is used, the dissipation due to evaporation of the solvent is extremely reduced, so that the storage stability is improved, and the preparation of the solution composition (printing ink) for forming the protective film (roll kneading, etc.) ) Is easier,
Alternatively, the silkscreen printing can be suitably performed without any trouble using the printing ink, and therefore, it is optimal.

Further, the polyimide siloxane in the present invention,
While maintaining excellent mechanical strength and electrical insulation,
Since it has high heat resistance, it can be suitably used as a surface protective film or an interlayer insulating film of various electric or electronic components (particularly, flexible wiring boards).

The polyimidesiloxane composition (solution composition) of the present invention is applied to the surface of a substrate, such as a flexible wiring board, which is various electric or electronic members, by a known means, and then dried and heated at a relatively low temperature. Thereby, a protective film (thickness: about 0.5 to 500 μm) having excellent performance can be formed.

The method for producing the polyimidesiloxane in the present invention includes, for example, (a) an aromatic tetracarboxylic acid component mainly containing 2,3,3 ', 4'-biphenyltetracarboxylic acids; Diaminopolysiloxane represented by Wherein l is from 3 to 30, preferably from 4 to 20, 60 to 75 mol%, and ii) 25 to 40 mol% of aromatic diamine
And a diamine component consisting of, approximately equimolar, in an organic polar solvent, by heating to a high temperature of 120 ° C. or higher, and polymerizing and imidizing in one step, or a method of producing a polyimide siloxane, or the two components described above. Is polymerized in a substantially equimolar, organic polar solvent at a low temperature of 80 ° C. or less to produce a polyamic acid (polyimide precursor), and the polyamic acid is subjected to an appropriate condition (chemical imidization or high-temperature heating). Imidation) to produce a polyimide siloxane.

In the aromatic tetracarboxylic acid component, 20 mol% or less, particularly 15 mol%, based on the total tetracarboxylic acid component
The "other aromatic tetracarboxylic acid compounds" which can be used together with 2,3,3 ', 4'-biphenyltetracarboxylic acids in the following ratios include 3,3', 4,4'-biphenyl Tetracarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 3,3', 4,4'-biphenylethertetracarboxylic acid, pyromellitic acid, or dianhydride of those acids, or And esterified products of these acids.

As the diaminopolysiloxane represented by the above general formula, R ₁ in the general formula is a divalent hydrocarbon residue consisting of “a plurality of methylene groups” having 2 to 6 carbon atoms, particularly 3 to 5 carbon atoms, or a phenylene group. It is preferable that R ₂ is independently an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, or a propyl group, or a phenyl group, and further, 1 is 3 to 30, preferably 4 to 20, Particularly, it is preferably about 5 to 15.

As the diaminopolysiloxane represented by the above general formula, for example, a compound represented by the following general formula (l is 3 to 30, preferably 4 to 20) can be suitably mentioned.

Y, which is a divalent organic residue in the general formulas (3) and (4), is a residue of a polycyclic aromatic diamine having 2 to 4 benzene rings. Examples of the polycyclic aromatic diamine include 4,4'-diaminodiphenyl ether and 4,4'-
Diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, o-tolidine, o-dianisidine (above,
A polycyclic aromatic diamine compound having two benzene rings),
1,4-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) benzene (the above is a polycyclic aromatic diamine compound having three benzene rings), bis [4-
(4-aminophenoxy) phenyl] sulfone, or
2,2-bis [4- (4-aminophenoxy) phenyl]
Propane (the above is a polycyclic aromatic diamine compound having four benzene rings) is used.

The aromatic diamine may be a polycyclic aromatic diamine compound having 2 to 4 benzene rings and a benzene ring in an amount of 20 mol% or less, particularly 16 mol% or less based on the total aromatic diamine. It is also possible to use one aromatic diamine compound having one benzene ring. Examples of such an aromatic diamine compound having one benzene ring include paraphenylenediamine, metaphenylenediamine, 2,4-diaminotoluene, and 3,4-diaminotoluene. Examples thereof include 5-diaminobenzoic acid, 2,6-diaminobenzoic acid, and 3,5-diaminobenzyl allylate.

In the polyimide siloxane of the present invention,
If the content ratio of the “main chain unit based on diaminopolysiloxane” is too small relative to the total diamine component, the solubility of such a polyimidesiloxane may be reduced, or the use of a solution of such a polyimidesiloxane may cause the polyimide to become flexible. When a protective film is formed on a wiring board, it is not suitable because it becomes greatly curled.On the other hand, if the content of the “main chain unit based on diaminopolysiloxane” is too large, polymer heat resistance, mechanical It is not suitable because the physical properties are reduced.

As the organic polar solvent used in the method for producing the polyimide siloxane, for example, dimethyl sulfoxide,
Sulfoxide solvents such as diethylsulfoxide, N, N
-Dimethylformamide, formamide solvents such as N, N-diethylformamide, N, N-dimethylacetamide, acetamido solvents such as N, N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-
Pyrrolidone, pyrrolidone solvents such as N-vinyl-2-pyrrolidone, glyme solvents such as methyldiglyme, methyltridiglyme, hexamethylenephosphoramide, γ-butyllactone, cyclohexanone, etc., or phenol, o-, m -Or phenolic solvents such as p-cresol, xylenol, halogenated phenols (such as parachlorophenol and parabromophenol), and catechol.

Polyimide siloxane in the present invention is preferably a high molecular weight polymer, for example, concentration: 0.5 g /
The logarithmic viscosity (indicating the degree of polymerization of the polymer) measured at a measurement temperature of 30 ° C. in a polymer solution of 100 ml (N-methyl-2-pyrrolidone) is 0.05 to 3, particularly 0.1 to 2 The imidation ratio of polyimide siloxane (the ratio of “imide bond” by infrared absorption spectroscopy) is about 90% or more, particularly 95 to 100%.
%, And the absorption peak of “amide-acid bond” is not substantially found in the IR chart.

The organic solvent used in the polyimide siloxane composition (solution composition) for forming a low-curl coating film of the present invention has a boiling point of 140 to 280 ° C among the organic polar solvents used in the above-described method for producing a polyimide siloxane. For example, an organic polar solvent such as a pyrrolidone-based solvent or a glyme-based solvent can be used, and xylene, ethyl cellosolve, dioxane, or the like may be partially incorporated in the organic polar solvent.

Further, the composition of the present invention may contain an inorganic filler such as wollastonite, silica, and talc, a polymer filler, or an inorganic or organic dye.

In the polyimide siloxane composition of the present invention, the concentration of the above-mentioned polyimide siloxane is 5 to 50% by weight, particularly 10 to 50% by weight.
The solution viscosity is preferably 40% by weight, and the solution viscosity (rotation speed) at 25 ° C is preferably 0.01 to 10,000 poise, particularly preferably 0.1 to 1000 poise.

The polyimide siloxane composition of the present invention is a polyimide siloxane polymerization solution obtained by polymerizing and imidizing the aromatic tetracarboxylic acid component and the diamine component in an organic polar solvent in a single step as described above. Or a solution obtained by diluting the polymerization solution to an appropriate concentration with the same organic solvent as the polymerization solvent.

Alternatively, the polyimide siloxane composition can be prepared by once separating and isolating powdery polyimide siloxane from the above-mentioned polymerization solution, and uniformly dissolving the isolated polyimide siloxane powder in an organic solvent.

The polyimide siloxane composition for forming a low-curl coating film according to the present invention comprises an object to be coated (a flexible circuit board,
Semiconductor, etc.), at room temperature or under heating, spin coating machine,
By a method using a dispenser or a printing machine or the like, apply to a uniform thickness to form a coating film composed of the solution composition, and then apply the coating film to about 50 ° C. or more, particularly 60 to 250 ° C.
By drying at about the temperature, a solidified film (protective film) of polyimidesiloxane can be formed.

The polyimide siloxane composition for forming a coating film of the present invention makes it possible to obtain a flexible substrate having substantially no warp and little or no curl in a protective film by a warp test described later.

In this specification, the warp test was performed on a 75 μm-thick aromatic polyimide film (manufactured by Ube Industries, Ltd., UPILEX S-
75) A 100 μm-thick spacer made of polyethylene terephthalate (PET) is arranged on the top, and the polyimidesiloxane solution composition is bar-coated with a laboratory coating rod within a range surrounded by the spacer,
Forming a coating layer of the solution composition, and finally, coating the coating layer on the substrate at 80 ° C. for 30 minutes, 150 ° C. for 30 minutes, and 200
Drying and heat treatment (baking) at 30 ° C. for 30 minutes to form a protective film made of polyimide siloxane (average thickness: 40 μm), and the resulting polyimide film having the protective film formed thereon (length: 100 mm × width) : 50mm) “Radius of curvature”
Means what was done by measuring

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Each test method in Examples and Comparative Examples is as follows.

The solubility of the polyimide siloxane, polyimide siloxane powder 0.2g, at 20 ℃, added to methyl diglyme 0.8g, left to observe the state of dissolution, when dissolved within 1 hour ◎, If dissolved within 1 day,
The case where the solvent partially swells in the polymer is indicated by △, and the case where the solvent is completely insoluble even for one week is indicated by ×.

The starting temperature of thermal decomposition of polyimide siloxane is
Measured with a 951 thermogravimeter.

The mechanical strength of polyimide siloxane
A 200 μm spacer was arranged as a frame, and a 30% by weight polymer solution was cast on the glass plate to form a thin film. The thin film was heated at 80 ° C. for 30 minutes, 150 ° C. for 30 minutes, and 200 ° C.
And a heat treatment for 30 minutes to form a film having a thickness of about 50 μm. The polyimide siloxane film was subjected to a tensile strength tester (Tensilon UTM-11-20 manufactured by Orientec, Inc.) using a universal tensile tester. The elongation and initial elasticity were measured.

Example 1 [Production of polyimide siloxane] A glass separable flask having a capacity of 2,
3 ', 4'-biphenyltetracarboxylic dianhydride (a-B
(PDA) 147.2 (500 mmol) and 1274 g of N-methyl-2-pyrrolidone (NMP) were dissolved in a-BPDA, and the solution was stirred at room temperature while diaminopolysiloxane (DAPS) [Shin-Etsu X-22-16, manufactured by Silicon Corporation
_{1AS, R :-( CH 2) 3} -, R 2: methyl group, l = 9] 304.9g
(346.5 mmol) and 530 g of diglyme in 3
0 minutes, while passing nitrogen gas at a polymerization temperature of 190 ° C,
Moreover, the polymerization reaction was carried out for 3 hours while refluxing methyl diglyme to remove water, and the reaction solution was once returned to room temperature and stirred, and the cooled reaction solution was added to the reaction solution.
2,2-bis [4- (4-aminophenoxy) phenyl]
Propane (BAPP) 62.19 g (151.25 mmol) and NMP 500 g
Solution was added dropwise over 30 minutes, and the reaction temperature was 200
The reaction was carried out at ℃ 210 ° C. for 6 hours.

Finally, add the reaction to 20 methanol,
Precipitate for 30 minutes using a disperser, isolate the polymer powder by filtration with a polymer, and perform "washing for 10 minutes using a disperser in 10 methanol" twice on the polymer powder. For 8 hours to obtain 428.9 g of a polyimidesiloxane powder.

The polyimide siloxane obtained as described above is
The logarithmic viscosity (30 ° C.) was 0.24, and the imidization ratio was substantially 100%.

(Preparation of polyimide siloxane solution composition)

3.5 g of polyimide siloxane manufactured as described above
Was dissolved in 7 g of methyldiglyme at room temperature to prepare a solution composition of polyimidesiloxane having a polymer concentration of 35% by weight in which the polyimidesiloxane was uniformly dissolved in methyldiglyme.

The solution composition had a solution viscosity (rotational viscosity) of 3500 centipoise at 25 ° C.

[Coating operation of solution composition: formation of protective film]

100 μm thick PET on a flexible wiring board (line width: about 300 μm, wiring density: 60%) using a 75 μm thick aromatic polyimide film (Ubelex S-75, manufactured by Ube Industries, Ltd.) as a substrate And a polyimide coating solution (N) within the area surrounded by the spacer.
o.3) by bar coating to form a coating layer of the solution composition, and finally, the coating layer on the substrate at 80 ℃ for 30 minutes,
By drying and heating (baking) at 150 ° C. for 30 minutes and 180 ° C. for 30 minutes, a protective film (average thickness: 40 μm) made of polyimidesiloxane was formed.

The flexible wiring board on which the protective layer is formed is substantially free of curl, and the adhesion between the protective layer and the wiring board shows no adhesion at all according to a board test (peeling off with an adhesive tape). There was no problem and both were firmly bonded.

In another warp test, the polyimide film on which the protective film was formed had a “warp radius of curvature” of 100 mm or more, and was substantially free from warpage (no warpage).

Examples 2-3 and Comparative Examples 1-5 As the aromatic tetracarboxylic acid component, an aromatic tetracarboxylic acid compound of the type shown in Table 1 was used, and as the diamine component, the type and amount (mol) shown in Table 1 were used. Ratio) of diaminopolysiloxane and polyimide siloxane (imidization rate: 95%) in the same manner as in Example 1.
Above) were manufactured respectively.

For those polyimide siloxanes, logarithmic viscosity,
Table 1 shows the heat resistance, solubility, and mechanical properties.

Since the polyimide siloxanes obtained in Comparative Examples 1 and 2 are substantially insoluble in organic solvents such as NMP and dioxane, a solution composition of the polyimide siloxane cannot be prepared. Could not be formed, so that the mechanical properties could not be measured and the warpage test could not be performed.

In addition, since the polyimide siloxanes obtained in Comparative Examples 3 and 4 are not sufficiently dissolved in methyldiglyme, a solution composition of the polyimide siloxane was prepared using a solvent: NMP, and a polyimide siloxane film was prepared. Was formed and the mechanical properties of the film were measured.

Except for using “soluble polyimide siloxanes” produced as described above, in the same manner as in Example 1,
Polyimide siloxane solution composition (polymer concentration: 35
% By weight).

 Table 1 shows the solution viscosity (25 ° C.) of each solution composition.

A coating operation was performed in the same manner as in Example 1 except that the above-described solution compositions were used, and the state of the state was observed.
Further, a warpage test was separately conducted, and the results (good / bad quality of coating operation, radius of curvature of curvature) are shown in Table 1.

The abbreviations used in Table 1 have the following meanings.

a-BPDA; 2,3,3 ', 4'-diphenyltetracarboxylic dianhydride PMDA; pyromellitic dianhydride BTDA; 3,4,3', 4'-benzophenonetetracarboxylic dianhydride BAPP; 2,2-bis [4- (4-aminophenoxy) phenyl] propane DAPS; diaminopolysiloxane (X-22-161AS) Example 4 In preparing a solution composition, the polyimide siloxane prepared in Example 1 was used, and as an organic solvent:
A solution composition was prepared in the same manner as in Example 1 except that methyltriglyme having a boiling point of 216 ° C was used. The solution composition had a solution viscosity (rotational viscosity) at 25 ° C. of 4000 centipoise.

Using the solution composition described above, coating is performed by a screen printing method (using a stainless screen with a screen thickness of 81 μm and a film thickness of 16 μm using a 200 mesh) using a flexible wiring board having through holes formed therein. Further, except that the conditions of drying and heat treatment of the applied film were set to 80 ° C. for 30 minutes, 150 ° C. for 30 minutes, and 200 ° C. for 30 minutes, protection was performed on the flexible wiring board in the same manner as in Example 1. A film (average thickness: 40 μm) was formed. The screen printing can be performed favorably, and the flexible wiring board on which the protective layer is formed is substantially free of curl as in Example 1. The adhesion between them was also good.

Further, in a warpage test separately performed using the solution composition, the polyimide film on which the protective film was formed,
The “warp radius of curvature” was 100 mm or more, and there was substantially no warpage (no warpage).

(Operation and effect of the present invention)

The polyimide siloxane for forming a coating film of the present invention is a flexible polymer having a considerably high proportion of structural units based on diaminopolysiloxane, and thus retains heat resistance, electrical properties, and mechanical properties. In addition, its solubility in organic solvents (especially solubility in methyldiglyme and methyltriglyme) is extremely excellent.
A polyimide siloxane solution composition obtained by uniformly dissolving the polyimide siloxane in an organic solvent such as methyl diglyme or methyl triglyme is applied to an aromatic polyimide film used for a substrate such as a flexible wiring board. It is possible to form a heat-resistant and electrically insulating protective film firmly adhered to the substrate by drying and heat treatment, and in that case, the substrate is substantially free from warpage. .

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-11631 (JP, A) JP-A-2-91124 (JP, A) JP-A-1-121325 (JP, A) JP-A-61- 42573 (JP, A) JP-A-63-317554 (JP, A)

Claims (2)

(57) [Claims] 1. An aromatic tetracarboxylic acid component containing 80 to 100 mol% of 2,3,3 ', 4'-biphenyltetracarboxylic acid, an acid ester or an acid dianhydride thereof, and a diaminopolysiloxane 60 to 100%. The following structural units (a) and (b) obtained by polymerizing and imidizing a diamine component consisting of 75 mol% and 25 to 40 mol% of a polycyclic aromatic diamine having 2 to 4 benzene rings, Of polyimidesiloxane having a logarithmic viscosity of 0.05 to 3 (0.5 g / 100 ml N-methyl-2-pyrrolidone, 30 ° C.) in an organic solvent having a boiling point of 140 to 280 ° C. % (Concentration of polymer in the solution) is uniformly dissolved, and there is substantially no warpage in the warp test measured by forming a protective film of polyimide siloxane on the aromatic polyimide film. Characterized by Karl coating polyimide siloxane composition for forming. (A) 60-75 mol% In (a), in a total of 100 mol% of (1) and (2),
(1) is 80 to 100 mol%, and (2) is 0 to 20 mol%. (B) 25-40 mol% In (b), a total of 100 mol% of (3) and (4)
(3) is 80 to 100 mol%, and (4) is 0 to 20 mol%. In the above formula, X is R ₁ represents a plurality of methylene groups having 2 to 6 carbon atoms or a phenylene group, R ₂ independently represents an alkyl group or a phenyl group having 1 to 3 carbon atoms, l is an integer of 3 to 30 Show, Y
Represents a divalent organic residue. 2. An aromatic tetracarboxylic acid component containing 80 to 100 mol% of 2,3,3 ', 4'-biphenyltetracarboxylic acid, an acid ester or an acid dianhydride thereof, and a diaminopolysiloxane 60 to 100%. The following structural units (a) and (b) obtained by polymerizing and imidizing a diamine component consisting of 75 mol% and 25 to 40 mol% of a polycyclic aromatic diamine having 2 to 4 benzene rings, A polyimidesiloxane having a logarithmic viscosity of 0.05 to 3 (0.5 g / 100 ml N-methyl-2-pyrrolidone, 30 ° C.) is added to an organic solvent having a boiling point of 140 to 280 ° C. in an amount of 5 to 50% by weight. % (Concentration of polymer in the solution) is uniformly dissolved, and furthermore, there is substantially no warpage in a warp test measured by forming a protective film of polyimidesiloxane on the aromatic polyimide film. Curl film formation After the polyimide siloxane composition applied to a substrate, dried by heating formed by film. (A) 60-75 mol% In (a), in a total of 100 mol% of (1) and (2),
(1) is 80 to 100 mol%, and (2) is 0 to 20 mol%. (B) 25-40 mol% In (b), a total of 100 mol% of (3) and (4)
(3) is 80 to 100 mol%, and (4) is 0 to 20 mol%. In the above formula, X is R ₁ represents a plurality of methylene groups having 2 to 6 carbon atoms or a phenylene group, R ₂ independently represents an alkyl group or a phenyl group having 1 to 3 carbon atoms, l is an integer of 3 to 30 Show, Y
Represents a divalent organic residue.