TW201927943A - Coating solution for glass substrate - Google Patents

Abstract

The present invention provides a coating solution having a good preservation stability, which can sufficiently ensure adhesive properties to a glass substrate even when a heating rate is accelerated in thermal curing of a polyamic acid (PAA) film and be easily peeled off from the glass substrate as a polyimide film after the thermal curing. The present invention relates to a coating solution for a glass substrate, comprising a PAA, an amide solvent and an alkoxysilane compound and having the following characteristic: (1) a content of the alkoxysilane compound is more than 5 ppm and less than 100 ppm with respect to a mass of the PAA; and (2) a molecular weight of the alkoxysilane compound is 100 or more and 300 or less.

Description

Coating solution for glass substrate

The present invention relates to a coating solution containing polyamic acid (PAA) as a precursor of polyimide (PI), and the coating solution is applied to a glass substrate.

Previously, in the fields of liquid crystal displays (LCD), plasma display panels (PDP), organic EL displays (OLED), flat panel displays (FPD), and electronic devices such as electronic paper, electronic components were mainly formed on glass substrates. However, since the glass substrate is rigid and lacks toughness, it is difficult to become flexible.

Therefore, a method of using a PI film having flexibility and having good heat resistance and dimensional stability as a flexible substrate has been proposed. For example, it has been proposed to use a PAA solution as a precursor of PI, dry it to form a PAA coating film, and heat-harden it to produce a state in which a PI film is laminated and integrated on a glass substrate. That is, after the electronic component is formed on the surface of the PI film laminated on the glass substrate, the PI film is finally peeled from the glass substrate, thereby making a flexible substrate. During the above-mentioned thermal curing process, when the PAA coating film formed on the glass substrate is converted into a PI film, the coating film may be peeled from the glass substrate, or air bubbles may remain on the surface of the formed PI film. In particular, in order to improve production efficiency, this problem becomes apparent when the temperature rise rate during thermal curing is increased.

Therefore, it is necessary to sufficiently ensure the adhesion of the PAA coating film to the glass substrate during thermal curing. As a method to ensure the tightness, it is known to adjust the PAA A method of preparing a PI film by applying a solution containing an alkoxysilane compound on a glass substrate, and then thermally curing the PAA coating film. For example, Patent Document 1 (Example) discloses an example of a PAA solution prepared by blending 200 to 500 ppm of an alkoxysilane compound and 500 to 800 ppm of a polysiloxane-based surfactant with respect to the PAA mass. Patent Document 2 (Claim 1) discloses a method for improving the adhesion between a PI film and a glass substrate by using a PAA solution prepared by blending an alkoxysilane compound at a concentration of 100 to 20,000 ppm with respect to the PAA quality. Patent Document 3 (Claim 1) discloses an alkoxysilane modified by heating a PAA solution prepared by mixing 500 to 1,000 ppm of an alkoxysilane compound with respect to the mass of the PAA to about 50 ° C. Method of improving the PAA solution and improving the adhesion between the PI film and the glass substrate.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6067740

[Patent Document 2] Japanese Patent No. 6172139

[Patent Document 3] International Publication No. 2016/024457

However, in the previously disclosed method, since a large amount of an alkoxysilane compound is blended in the PAA solution, there is a concern that the mechanical properties, electrical properties, and optical properties of the obtained PI film may be impaired. In addition, the adhesion between the PI film and the glass substrate becomes too strong, and after the electronic element is formed on the surface of the PI film, it may be difficult to peel off the polyimide film from the glass substrate at the end. Furthermore, the viscosity of these PAA solutions may change during storage, and it is difficult to ensure good storage stability. Qualitative issues.

Therefore, the present invention is to solve the above problems, and an object of the present invention is to provide a coating solution, which can sufficiently secure the adhesion to a glass substrate even if the temperature of the PAA coating film is heat-cured, and heat-cured. It can be easily peeled off from the glass substrate in the form of a PI film, and its storage stability is good.

The present inventors have made intensive research in order to solve the above-mentioned problems, and as a result, they have found that the above-mentioned problems are solved by using a PAA solution containing a specific amount of a specific alkoxysilane compound, and the present invention has been completed.

The present invention has the following gist.

<1> A coating solution for a glass substrate, comprising a PAA, an amidine-based solvent, and an alkoxysilane compound, characterized in that: 1) the content of the alkoxysilane compound exceeds 5 ppm relative to the mass of the PAA and Less than 100 ppm; 2) The molecular weight of the alkoxysilane compound is 100 or more and 300 or less.

<2> A method for manufacturing a coating solution for a glass substrate, which comprises a polyamidoacid (PAA) which is a precursor of polyimide (PI), a fluorene-based solvent, and an alkoxysilane compound. The method for producing a coating solution is characterized in that when an alkoxysilane compound having a molecular weight of 100 or more and 300 or less is prepared in a PAA solution, the compounding amount of the alkoxysilane compound is set to more than 5 ppm relative to the mass of the PAA. It is less than 100 ppm, and the compounding amount of the alkoxysilane compound is adjusted according to the thickness of the target PI film.

<3> A method for manufacturing a laminated body including a PI film and a glass substrate, which is coated with a coating solution such as <1> on a glass substrate, dried, and then heat-hardened. And forming a polyimide (PI) film on a glass substrate, which is characterized in that it is thermally cured by continuously increasing the temperature, and the upper limit temperature during thermal curing is set to 350 ° C or higher and 500 ° C or lower. .

By using the PAA solution of the present invention, when the PAA coating film is thermally hardened, the adhesion to the glass substrate can be sufficiently ensured even if the temperature rise rate is increased. The PI film after heat curing can be easily peeled from the glass substrate in the form of a PI film. Therefore, the PAA solution can be preferably used as a solution for manufacturing a flexible substrate including a PI film formed with electronic components.

Hereinafter, the present invention will be described in detail.

The PAA solution of the present invention is coated on a glass substrate. As the glass substrate, for example, a substrate containing soda-lime glass, borosilicate glass, or alkali-free glass can be used. Among these, an alkali-free glass substrate can be preferably used. These glass substrates may be subjected to a known surface treatment such as a silane coupling agent treatment.

The thickness of the glass substrate is preferably 0.3 to 5.0 mm. If the thickness is less than 0.3 mm, the operability of the substrate may be reduced. Moreover, when thickness is more than 5.0 mm, productivity may fall.

The PAA solution of the present invention is obtained by blending an alkoxysilane compound in a PAA solution obtained by subjecting a tetracarboxylic acid and a diamine as raw materials to a polymerization reaction in an amidine solvent. Here, the term "approximately equal moles" refers to 0.9 moles or more and 1.0 moles of diamine relative to 1 mole of tetracarboxylic acids. the following.

Examples of the tetracarboxylic acids (tetracarboxylic acids, dianhydrides or esters thereof) include pyromellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acids, 4,4'-hexa Fluoroisopropylidenephthalic acid, 2,3,3 ', 4'-biphenyltetracarboxylic acid, 2,2', 3,3'-biphenyltetracarboxylic acid, 4,4'-oxybisphthalic acid, 3,3 ', 4,4'-benzophenone tetracarboxylic acids, 3,3', 4,4'-diphenylphosphonium tetracarboxylic acids, terphenyltriphenyltetracarboxylic acids, m-triphenyltetracarboxylic acids Wait. These tetracarboxylic acids can be used as a monomer or as a mixture. Among these, from the viewpoints of heat resistance and dimensional stability of the obtained PI, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dicarboxylic acid are preferred. Anhydride (PMDA), 4,4'-hexafluoroisopropylidenephthalic dianhydride (6FDA) and mixtures thereof.

Examples of the diamine include p-phenylenediamine (PDA), m-phenylenediamine, 4,4'-oxydiphenylamine (ODA), and 3,3'-bistrifluoromethyl-4,4'-di Aminobiphenyl (TFMB), 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diamine Diphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,2-bis (aniline) ethane, diaminodiphenylphosphonium, diamine Benzamidine aniline, diaminobenzoate, diaminodiphenyl sulfide, 2,2-bis (p-aminophenyl) propane, 2,2-bis (p-aminophenyl) hexafluoro Propane, 1,5-diaminonaphthalene, diaminotoluene, diaminotrifluorotoluene, 1,4-bis (p-aminophenoxy) benzene, 4,4'-bis (p-aminophenoxy) Group) biphenyl, diaminoanthraquinone, 4,4'-bis (3-aminophenoxyphenyl) diphenylfluorene and the like. These aromatic diamines can be used as a monomer or as a mixture. Among these, from the viewpoints of heat resistance and dimensional stability of the obtained PI, PDA, ODA, TFMB, and a mixture of these are preferable.

Examples of the amidine-based solvent include N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), and N, N-dimethylacetamide (DMAc). Wait. These solvents may be used alone or in the form of a mixture. Of these, the PAA From the viewpoint of solubility, NMP, DMAc, and a mixture thereof are preferred. These solvents are preferably dehydrated, and the water content thereof is preferably 500 ppm or less, and more preferably 200 ppm or less. With this setting, the water content in the PAA solution can be reduced, and hydrolysis of the alkoxysilane compound during storage can be prevented.

The reaction temperature when producing a PAA solution is preferably -30 to 70 ° C, and more preferably -15 to 60 ° C. In this reaction, the order of adding the monomer and the solvent is not particularly limited, and may be any order. The solid content concentration of PAA is preferably 1 to 50% by mass, and more preferably 5 to 30% by mass. The PAA can also be partially imidized. Regarding the viscosity of the PAA solution obtained in this way, from the viewpoint of coatability, the solution viscosity at 30 ° C is preferably set to 3 Pa. s or more and 100Pa. s or less. Moreover, these PAA solutions can also use a commercial item. As commercially available products, it is preferable to use "U Imide Varnish AH, AR" (manufactured by Unigeco), "YuPia-ST" (manufactured by Ube Kosan Co., Ltd.), and "PI-2611" (Hitachi Chemical DuPont MicroSystems) Manufacturing) etc. These are NMP solutions of PAA obtained using BPDA as an acid component and PDA as a diamine component.

The PAA solution of the present invention can be obtained by compounding an alkoxysilane compound in the PAA solution obtained in the manner described above. Here, the compounded amount of the alkoxysilane compound must be more than 5 ppm and less than 100 ppm based on the mass of the PAA. Furthermore, the molecular weight of the alkoxysilane compound must be 100 or more and 300 or less.

Examples of such an alkoxysilane compound include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, and N-2- (aminoethyl) -3- Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane (APMS), 3-aminopropyltriethoxysilane (APES), 3-triethoxysilane-N- ( 1,3-dimethyl-butylene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 2- (3,4-ethoxy (Cyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldi Ethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxy Silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3 -Ureidopropyltriethoxysilane (UPES), 3-ureidopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Isocyanatopropyltriethoxysilane and the like. Among these, 3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, and mixtures thereof are preferable.

By formulating the compounding amount and molecular weight of the alkoxysilane compound as described above, when the PAA coating film is thermally cured, the adhesion to the glass substrate can be sufficiently ensured even if the temperature is increased, and after thermal curing, , Can be easily peeled from the glass substrate in the form of PI film. In addition, by setting it as such, a PAA solution having good storage stability can be prepared. The compounded amount of the alkoxysilane compound can be confirmed by liquid chromatography mass spectrometry (LC-MS).

The PAA solution of the present invention can also be partially modified with an alkoxysilane compound by heating it to about 50 ° C.

In the PAA solution of the present invention, since the compounding amount of the alkoxysilane compound is set to the above-mentioned range, the adhesion and peelability to the glass substrate can be ensured even if the heating rate is increased, so it is preferably substantially Some other additives, such as those disclosed in Patent Document 1, are prepared to impair the mechanical properties of the PI film. Surfactants such as polysiloxane surfactants and fluorine-based surfactants. Here, the term "substantially not blended" means that the blended amount does not reach 1 ppm. By doing so, the original good mechanical, electrical, and optical properties of PI can be ensured.

In the PAA solution of the present invention, fine particles such as silicon dioxide and aluminum oxide can also be blended in a range that does not impair the transparency and other optical characteristics of the PI film. The volume average particle diameter (by a dynamic light scattering method) of these fine particles is preferably 10 nm or more and 100 nm or less. The blending amount is preferably 5 mass% or more and 20 mass% or less based on the mass of the PAA.

In the PAA solution of the present invention, other polymers may be added within a range that does not impair the effect of the present invention.

The PAA solution of the present invention is formed by laminating a PAA coating film into a PI film by coating on a glass substrate, drying and heat curing, and then forming a PI film by forming electronic components on the surface. It can be made into a flexible substrate by peeling it from a glass substrate.

When the PAA solution of the present invention is applied to a glass substrate, it is preferable to adjust the compounded amount of the alkoxysilane compound according to the thickness of the target PI film. That is, it is preferable that the smaller the thickness of the PI film, the lower the blending amount. In addition, it is preferable that the larger the thickness of the PI film, the higher the blending amount. By setting in this way, the adhesiveness to the glass substrate and the peelability from the glass substrate can be more fully ensured, and the blending amount of the alkoxysilane compound can be minimized according to the thickness.

As a method for applying the PAA solution to a glass substrate, known methods such as table coating, dip coating, bar coating, spin coating, die coating, and spray coating can be used in a continuous or batch manner. Coating.

When drying and heat curing, you can use ordinary hot air dryer, infrared Line lights and so on. The drying temperature is preferably set to 40 ° C to 150 ° C, and the drying time is preferably set to about 5 to 30 minutes.

Preferably, the dried coating film is continuously heated, and the PAA coating film is thermally cured to form a PI film. By continuously increasing the temperature, the effect obtained by blending an alkoxysilane compound exceeding 5 ppm and not exceeding 100 ppm with respect to the PAA solution can be made more effective. In the case of thermal curing, it is preferably performed under an atmosphere of an inert gas such as nitrogen or argon. Regarding the temperature increase rate during thermal curing, from the viewpoints of the balance between the adhesion of the PAA coating film to the glass substrate, the peelability of the PI film from the glass substrate, and the productivity, it is preferably 1 ° C / min ~ 15 ° C / It is performed at min, and more preferably at 3 ° C / min to 10 ° C / min. The upper limit temperature at the time of temperature increase is preferably 350 ° C or higher and 500 ° C or lower.

The adhesion between the PAA coating film obtained from the PAA solution of the present invention and the glass substrate is good. Therefore, even if the temperature increase rate during temperature increase is set to a relatively fast temperature increase rate of 3 ° C / min to 10 ° C / min, It can also prevent bubbles or bulging in the PAA coating film.

The laminated body obtained in the manner as described above can easily peel the PI film from the glass substrate after forming an electronic element on the surface of the PI film, and thus can be used for the manufacture of electronic devices.

The thickness of the PI film after peeling from the glass substrate is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less. When the PAA solution of the present invention is used, the amount of alkoxysilane can be adjusted, and even when the thickness is relatively thick, for example, about 30 μm, it can be thermally cured without generating bubbles or bulging. For example, when the target PI film has a thickness of 10 μm or more (especially 15 μm or more and 40 μm or less), it is preferable to set the compounding amount of the alkoxysilane compound to 25 ppm or more (especially 25 ppm or more and less than 100). ppm).

As the electronic component, all the electronic components used in the field of the previous electronic devices can be used. The method for forming the electronic device may be a method known in the field of electronic devices using a PI film as a flexible substrate.

Examples of the electronic device include flexible devices such as a flat panel display (FPD) such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic EL display (OLED), and an electronic paper.

[Example] <PAA solution A-1>

As PAA solution A-1, U IMIDE VARNISH AR (NMP solution for BPDA / PDA) was prepared. The viscosity of the PAA solution at 30 ° C was 4.3 Pa. The solid content concentration of s and PAA was 19.1% by mass relative to the mass of A-1.

<PAA solution B-1>

In a glass reaction vessel, a PDA (0.600 mol) was put into a NMP (polymerization solvent) having a water content of 200 ppm or less under a nitrogen atmosphere, and the PDA was dissolved. While cooling the solution to below 30 ° C with a cannula, slowly add BPDA (0.612 moles), and then polymerize at 60 ° C for 100 minutes to obtain a solution viscosity of 75Pa at 25 ° C. s, and the PAA solid content concentration is 20% by mass of the PAA solution with respect to the mass of B-1.

<PAA solution C-1>

In a glass reaction vessel, under a nitrogen atmosphere, PDA (0.550 mol) and ODA (0.050 mol) was charged with NMP (polymerization solvent) having a water content of 200 ppm or less, and the PDA and ODA were dissolved. While cooling the solution to below 30 ° C with a cannula, slowly adding BPDA (0.605 moles), and then polymerizing at 60 ° C for 100 minutes, thereby obtaining a solution viscosity of 98.5Pa at 25 ° C. s, and the PAA solid content concentration of the PAA solution is 20% by mass based on the mass of C-1.

<PAA solution D-1>

In a glass reaction vessel, under a nitrogen atmosphere, PDA (0.5 mol) and TFMB (0.1 mol) were charged into NMP (polymerization solvent) having a water content of 200 ppm or less, and the PDA and TFMB were dissolved. While cooling the solution to below 30 ° C with a cannula, slowly add BPDA (0.505 mol) and 6FDA (0.1 mol), and then polymerize at 60 ° C for 100 minutes to obtain a temperature of 25 ° C. The solution viscosity was 86.4Pa. s, and the PAA solid content concentration is 20% by mass of the PAA solution with respect to the mass of D-1.

<Example 1>

In A-1, 3-aminopropyltrimethoxysilane (APMS molecular weight: 179.3) was added to the mass of PAA at room temperature (25 ° C) by 30 ppm and stirred to obtain a uniform PAA solution ( A-2).

On the surface of an alkali-free glass substrate (20 cm square) with a thickness of 0.7 mm, apply A-2 by table coating, dry at 45 ° C for 10 minutes, dry at 70 ° C for 5 minutes, and 150 ° C. Then, it was dried for 5 minutes to form a PAA coating film. Then, the PAA coating film was thermally hardened by increasing the temperature to 450 ° C. at a temperature rising rate of 0.5 ° C./minute or 5 ° C./minute under a nitrogen gas flow, and maintaining the temperature at 450 ° C. for 10 minutes. In this way, obtained in glass A laminated body of a PI film having a thickness of 18 μm was formed on a glass substrate. The adhesion between the glass substrate and the PI film in the laminate was evaluated according to the following criteria, and the evaluation results are shown in Table-1.

<Adhesion evaluation>

When a uniform PI film can be formed on the glass substrate after heat curing, set it to "◎"; when the PI film is partially bulged on the glass substrate after heat curing, or if there are more than one part peeled off , Set to "△" (practical problems).

In addition, the peelability between the glass substrate and the PI film in the laminate was evaluated according to the following criteria, and the evaluation results are shown in Table-1.

<Evaluation of Peelability>

A 2.5 cm portion of the PI film from the end of the four sides was cut out with a cutter, and a PI film with an adhesive was attached to the end of the sample of the PI film having a square cut of 15 cm on one side. When the PI tape was pulled, When the PI film that is in close contact with the glass substrate can be easily peeled off, it is set to "◎"; when peeling off, there is a case where it is stuck (that is, the PI film is more secure at the interface between the PI film and the glass substrate When it adheres to a glass substrate and prevents peeling), it is set to "(delta)" (a practical problem).

<Example 2>

A PAA solution (A-3) was obtained in the same manner as in Example 1 except that the blended amount of APMS was 75 ppm with respect to the mass of PAA. In the same manner as in Example 1, a laminated body was produced and A-3 was evaluated. The evaluation results are shown in Table-1.

<Examples 3 and 4>

As the alkoxysilane, 3-aminopropyltriethoxysilane (APES molecular weight: 221.4) was used to prepare a PAA solution (A-4 ~ A-5) Except that, in the same manner as in Example 1, a laminated body was produced and evaluated. The evaluation results are shown in Table-1.

<Example 5>

A PAA solution (A-6) having an APMS compounding amount of 10 ppm based on the mass of the PAA and a thickness of the PI film of 9 μm was prepared. A laminated body was produced in the same manner as in Example 1 except that Evaluation. The evaluation results are shown in Table-1.

<Example 6>

A PAA solution (A-7) having a blending amount of APMS of 95 ppm relative to the mass of the PAA was prepared, and the thickness of the PI film was set to 21 μm. Except for this, a laminated body was produced in the same manner as in Example 1 and performed Evaluation. The evaluation results are shown in Table-1.

<Examples 7 and 8>

In B-1, 30 ppm and 75 ppm of APES were added to the PAA mass and stirred to obtain uniform PAA solution (B-2) and PAA solution (B-3), respectively. Using these solutions, a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1.

<Examples 9 and 10>

Because of C-1, add 20ppm and 40ppm APMS to PAA mass The mixture was stirred to obtain uniform PAA solution (C-2) and PAA solution (C-3). Using these solutions, a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1.

<Examples 11 to 13>

A laminated body was produced and evaluated in the same manner as in Example 1 except that the thickness of the PI film was set to 27 μm using A-6, A-7, and C-2. The evaluation results are shown in Table-1.

<Example 14>

By adding 20 ppm of 3-ureidopropyltriethoxysilane (UPES molecular weight: 264) to A-1 and stirring, a uniform PAA solution (A-8) was obtained. Using A-8, a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1.

<Example 15>

By adding 80 ppm of AMPS to D-1 and stirring, a uniform PAA solution (D-2) was obtained. Using D-2, a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1.

The PAA solutions used in Examples 1 to 15 were stored at 25 ° C for 10 days. As a result, the viscosity change rate of all the solutions was less than 5%, and good storage stability was confirmed.

<Comparative Examples 1, 2>

As the alkoxysilane, 3-aminopropyltriethoxysilane (APES molecular weight: 221.4) was used, and a PAA solution (A-9 and A- 10) Except for this, a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1. After the A-9 and A-10 were stored at 25 ° C for 10 days, the viscosity change rate was more than 5% in both PAA solutions.

<Comparative Examples 3 to 5>

As the alkoxysilane, bis (3-trimethoxysilylpropyl) -N-methylamine (BTMM molecular weight: 355.6) was used, and PAA was prepared by setting the compounded amount to the compounded amount described in Table-1. Except for the solutions (A-11 to A-13), a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1. After storing each of A-11 ~ A-13 at 25 ° C for 10 days, the viscosity change rate did not reach 5%.

<Comparative Examples 6 to 8>

Except having used A-1, B-1, and C-1 which do not contain an alkoxysilane as a PAA solution, it carried out similarly to Example 1, each produced the laminated body, and evaluated it. The evaluation results are shown in Table-1. The viscosity change rate of each of A-1, B-1, and C-1 after storage at 25 ° C for 10 days did not reach 5%.

<Comparative Example 9>

A PAA solution (A-14) having an APES blending amount of 5 ppm based on the mass of the PAA was prepared, and a laminated body was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table-1. After storing A-14 at 25 ° C for 10 days, the viscosity change rate did not reach 5%.

<Comparative Example 10>

A PAA solution (A-15) having an APMS compounding amount of 5 ppm based on the mass of the PAA and a thickness of the PI film of 10 μm was prepared. A laminated body was produced in the same manner as in Example 1 and was performed. Evaluation. The evaluation results are shown in Table-1. After storing A-15 at 25 ° C for 10 days, the viscosity change rate did not reach 5%.

In the case where the PAA solution of the present invention is used according to the examples, it can be judged that the formulation of the alkoxysilane compound is adjusted by adjusting the thickness of the PI film It is possible to ensure good adhesion and peelability even when the temperature rise rate during thermal curing is accelerated to 5 ° C / min. This situation is clear from the comparison between Example 11 and Example 12, or the comparison between Example 9 and Example 13. In addition, in the comparison between Example 1 and Example 2, or the comparison between Example 3 and Example 4, even if the compounded amount of the alkoxysilane compound was changed to 30 ppm and 75 ppm, the same adhesion and peelability were obtained. The result. The above-mentioned case is as described above, and the blending amount of the alkoxysilane compound is more preferably set to a smaller blending amount of 30 ppm. In addition, it was judged that the storage stability of the PAA solution of the present invention was good.

(Industrial availability)

The PAA solution of the present invention can be preferably used as a solution for manufacturing a flexible substrate including a PI film formed with electronic components.

Claims (3)

A coating solution for a glass substrate, which comprises a polyamidoacid (PAA), a fluorene-based solvent, and an alkoxysilane compound, characterized in that: 1) the content of the alkoxysilane compound relative to the PAA The mass is more than 5 ppm and less than 100 ppm; 2) The molecular weight of the alkoxysilane compound is 100 or more and 300 or less. A method for manufacturing a coating solution for a glass substrate, comprising a polyamic acid (PAA) which is a precursor of polyimide (PI), a fluorene-based solvent, and an alkoxysilane compound. The method for producing a solution is characterized in that when an alkoxysilane compound having a molecular weight of 100 or more and 300 or less is prepared in a PAA solution, the compounding amount of the alkoxysilane compound is more than 5 ppm and less than the mass of PAA. 100ppm, and the amount of alkoxysilane compound is adjusted according to the thickness of the target PI film. A method for manufacturing a laminated body including a PI film and a glass substrate, wherein a polyimide (PI) film is formed by applying a coating solution of claim 1 to a glass substrate and drying and then thermosetting the glass substrate. On a glass substrate, it is characterized by performing thermal curing by continuously increasing the temperature, and setting the upper limit temperature during thermal curing to 350 ° C or higher and 500 ° C or lower.