KR20200089287A - Polyimide resin, polyimide varnish and polyimide film - Google Patents

Abstract

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine, wherein structural unit A is derived from a compound represented by the following formula (a-1) (A-1) ), and a structural unit (A-2) derived from a compound represented by the following formula (a-2), and a structural unit (A-3) derived from a compound represented by the following formula (a-3). , The polyimide resin containing the structural unit (B-1) derived from the compound represented by the following formula (b-1), and the polyimide varnish and polyimide film containing the polyimide resin.

Description

Polyimide resin, polyimide varnish and polyimide film

The present invention relates to polyimide resins, polyimide varnishes and polyimide films.

Since the polyimide resin has excellent mechanical properties and heat resistance, various uses have been studied in fields such as electrical and electronic parts. For example, it is desired to replace a glass substrate used for an image display device such as a liquid crystal display or an OLED display with a plastic substrate for the purpose of weight reduction or flexibility of a device, and a polyimide resin suitable as the plastic material. Research is also ongoing. Color-transparency is also required for polyimide resins for this purpose, and further, high dimensional stability to heat (i.e., low coefficient of linear thermal expansion) is also required to cope with the high-temperature process of the manufacturing process of an image display device.

As a polyimide resin having a low coefficient of linear thermal expansion, for example, in Patent Document 1, first tetracarboxylic acid components such as pyromellitic anhydride and 3,3',4,4'-diphenylsulfonetetracarboxylic acid A polyimide resin synthesized from a second tetracarboxylic acid component such as dianhydride and a tolidine sulfone skeleton diamine component is described, and Patent Document 2 synthesizes from a diamine compound containing a benzoxazole group and an aromatic tetracarboxylic acid dianhydride The polyimide resin to be used is described.

In recent years, in the field of microelectronics, laser peeling processing, called laser lift-off (LLO), has attracted attention as a method of peeling the resin film from the support in the support on which the resin film is laminated. Therefore, in order to make the polyimide film compatible with laser peeling, laser peeling property is also required for the polyimide film. In order to be able to cope with peeling processing by XeCl excimer laser having a wavelength of 308 nm, it is required that the polyimide film has excellent properties of absorbing light having a wavelength of 308 nm (that is, the light transmittance at a wavelength of 308 nm is small). .

Furthermore, the polyimide film is also required to be resistant to organic solvents such as polar solvents (organic solvent resistance). When the film having poor organic solvent resistance is exposed to an organic solvent such as a polar solvent, the film may change shape due to elution or swelling of the surface.

Japanese Patent Publication 2010-053336 Japanese Patent Publication 2015-093915

The present invention has been made in view of the above circumstances, and the subject of the present invention is that mechanical properties and heat resistance are good, and furthermore, it is possible to form a film excellent in colorless transparency, heat dimensional stability, laser peelability and organic solvent resistance. It is to provide a polyimide resin and a polyimide varnish and a polyimide film containing the polyimide resin.

The present inventors have found that a polyimide resin containing a combination of specific structural units can solve the above problems and have completed the invention.

That is, the present invention relates to the following [1] to [5].

[One]

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine,

The structural unit A is a structural unit (A-1) derived from a compound represented by the following formula (a-1), and a structural unit (A-2) derived from a compound represented by the following formula (a-2), The structural unit (A-3) derived from the compound represented by the following formula (a-3) is included,

A polyimide resin in which the structural unit B contains a structural unit (B-1) derived from a compound represented by the following formula (b-1).

[Formula 1]

[2]

The proportion of the structural unit (A-1) in the structural unit A is 10 to 80 mol%,

The proportion of the structural unit (A-2) in the structural unit A is 10 to 80 mol%,

The polyimide resin according to the above [1], wherein the proportion of the structural unit (A-3) in the structural unit A is 10 to 80 mol%.

[3]

The polyimide resin according to the above [1] or [2], wherein the proportion of the structural unit (B-1) in the structural unit B is 50 mol% or more.

[4]

The polyimide varnish formed by dissolving the polyimide resin according to any one of [1] to [3] above in an organic solvent.

[5]

The polyimide film containing the polyimide resin in any one of said [1]-[3].

According to the present invention, it is possible to form a film having good mechanical properties and heat resistance, and furthermore, excellent in colorless transparency, heat dimensional stability, laser peelability, and organic solvent resistance. On the other hand, in the present invention, the excellent colorless transparency means that the total light transmittance is high, the yellow index is small, and the excellent dimensional stability to heat means a low linear thermal expansion coefficient.

[Polyimide resin]

The polyimide resin of the present invention is a polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine, in which the structural unit A is represented by the following formula (a-1) The structural unit (A-1) derived, the structural unit (A-2) derived from the compound represented by the following formula (a-2), and the structural unit derived from the compound represented by the following formula (a-3) (A-3) and the structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1).

[Formula 2]

<Structural Unit A>

The structural unit A is a structural unit derived from tetracarboxylic dianhydride in the polyimide resin, and is a structural unit (A-1) derived from a compound represented by formula (a-1) and formula (a-2). The structural unit (A-2) derived from the compound represented by and the structural unit (A-3) derived from the compound represented by Formula (a-3) are included. Colorless transparency and dimensional stability are improved by the structural unit (A-1), laser peelability and organic solvent resistance are improved by the structural unit (A-2), and by the structural unit (A-3) , Colorless transparency is improved.

The compound represented by the formula (a-1) is norbonan-2-spiro-α-cyclopentanone-α'-spiro-2”-norbonan-5,5”,6,6”-tetracarboxylic acid It is an anhydride.

The compound represented by formula (a-3) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride.

The compound represented by formula (a-2) is biphenyltetracarboxylic dianhydride (BPDA), and specific examples thereof include 3,3',4,4'- represented by the following formula (a-2s): Biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), represented by the following formula (a-2a) And 2,2',3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) represented by -2i).

[Formula 3]

The proportion of the structural unit (A-1) in the structural unit A is preferably 10 to 80 mol%, more preferably 15 to 55 mol%, still more preferably 20 to 45 mol%, particularly Preferably it is 22.5-40 mol%.

The proportion of the structural unit (A-2) in the structural unit A is preferably 10 to 80 mol%, more preferably 20 to 60 mol%, further preferably 25 to 50 mol%, particularly Preferably it is 27.5-45 mol%.

The proportion of the structural unit (A-3) in the structural unit A is preferably 10 to 80 mol%, more preferably 25 to 65 mol%, still more preferably 30 to 55 mol%, particularly Preferably it is 32.5-50 mol%.

The proportion of the total of the structural units (A-1) to (A-3) in the structural unit A is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol. % Or more, particularly preferably 99 mol% or more. The upper limit of the ratio of the sum of the constituent units (A-1) to (A-3) is not particularly limited, that is, 100 mol%. The structural unit A may consist of only the structural unit (A-1), the structural unit (A-2), and the structural unit (A-3).

The structural unit A may include structural units other than the structural units (A-1) to (A-3). The tetracarboxylic acid dianhydride that gives such a structural unit is not particularly limited, but aromatic tetracarboxylic dianhydride such as pyromellitic dianhydride and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride ( However, the compound represented by Formula (a-2) is excluded); Alicyclic tetracarboxylic dianhydride, such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride (except for compounds represented by formula (a-1) and compounds represented by formula (a-3)) do); And aliphatic tetracarboxylic dianhydride, such as 1,2,3,4-butane tetracarboxylic dianhydride, is mentioned.

On the other hand, in this specification, an aromatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing one or more aromatic rings, and includes one or more alicyclic tetracarboxylic dianhydrides, and also an aromatic ring It means tetracarboxylic dianhydride which does not contain, and aliphatic tetracarboxylic dianhydride means tetracarboxylic dianhydride which does not contain an aromatic ring or an alicyclic ring.

The structural units arbitrarily included in the structural unit A (that is, structural units other than the structural units (A-1) to (A-3)) may be one type, or two or more types.

<Structural Unit B>

The structural unit B is a structural unit derived from diamine in the polyimide resin, and includes a structural unit (B-1) derived from a compound represented by formula (b-1). By the structural unit (B-1), mechanical properties and dimensional stability are improved.

The compound represented by formula (b-1) is 2,2'-bis(trifluoromethyl)benzidine.

The proportion of the structural unit (B-1) in the structural unit B is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably It is 99 mol% or more. The upper limit of the proportion of the structural unit (B-1) is not particularly limited, that is, 100 mol%. The constituent unit B may consist of only the constituent unit (B-1).

The structural unit B may include structural units other than the structural unit (B-1). The diamine conferring such a constitutional unit is not particularly limited, but 1,4-phenylenediamine, p-xylylenediamine, 3,5-diaminobenzoic acid, 2,2'-dimethylbiphenyl-4,4' -Diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)hexafluoropropane, bis(4-aminophenyl)sulfone, 4,4'-diaminobenzanilide, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4 -Aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl) terephthalamide, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis [4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, and 9,9-bis(4-aminophenyl)fluorene Aromatic diamines such as compounds (excluding compounds represented by formula (b-1)); Alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; And aliphatic diamines, such as ethylenediamine and hexamethylenediamine, are mentioned.

On the other hand, in this specification, an aromatic diamine means a diamine containing one or more aromatic rings, and an alicyclic diamine means a diamine containing one or more alicyclics and does not contain an aromatic ring, and is an aliphatic diamine. It means a diamine containing neither an aromatic ring nor an alicyclic ring.

The structural units arbitrarily included in the structural unit B (that is, structural units other than the structural unit (B-1)) may be one type or two or more types.

The number average molecular weight of the polyimide resin of the present invention is preferably from 5,000 to 100,000 in terms of the mechanical strength of the resulting polyimide film. On the other hand, the number average molecular weight of the polyimide resin can be obtained, for example, from a standard polymethyl methacrylate (PMMA) conversion value by gel filtration chromatography measurement.

The polyimide resin of the present invention can form a film having good mechanical properties and good heat resistance, and furthermore, colorless transparency, heat dimensional stability, laser peelability, and organic solvent resistance. The favorable physical property values of the film which can be formed using the polyimide resin of the present invention are as follows.

The tensile strength is preferably 80 MPa or more, more preferably 100 MPa or more, and even more preferably 110 MPa or more.

The tensile modulus is preferably 2.5 GPa or more, more preferably 3.0 GPa or more, and still more preferably 3.2 GPa or more.

The glass transition temperature (Tg) is preferably 320°C or higher, more preferably 340°C or higher, and even more preferably 350°C or higher.

The total light transmittance is preferably 88% or more, more preferably 89% or more, and even more preferably 90% or more, when the film has a thickness of 10 μm.

When the yellow index (YI) is a 10 μm-thick film, it is preferably 2.9 or less, more preferably 2.7 or less, and even more preferably 2.5 or less.

The linear thermal expansion coefficient (CTE) is a CTE of 100 to 250°C, preferably 25 ppm/°C or less, more preferably 20 ppm/°C or less, and even more preferably 12 ppm/°C or less.

The light transmittance at a wavelength of 308 nm is preferably 1.0% or less, more preferably 0.6% or less, and even more preferably 0.4% or less, when a film having a thickness of 10 μm is used. The smaller the light transmittance at the wavelength 308 nm, the better the laser peelability by the XeCl excimer laser having a wavelength of 308 nm.

On the other hand, the tensile modulus, tensile strength, glass transition temperature (Tg), total light transmittance, yellow index (YI), linear thermal expansion coefficient (CTE) in the present invention, and light transmittance at a wavelength of 308 nm are specifically examples. It can be measured by the method described in.

[Method for manufacturing polyimide resin]

The polyimide resin of the present invention is a compound that gives the above-mentioned structural unit (A-1), a compound that gives the above-mentioned structural unit (A-2), and a compound that gives the above-mentioned structural unit (A-3) It can be produced by reacting a tetracarboxylic acid component containing and a diamine component containing a compound that gives the above-mentioned structural unit (B-1).

Examples of the compound that gives the structural unit (A-1) include a compound represented by formula (a-1), but are not limited thereto, and may be derivatives thereof in a range that gives the same structural unit. As the corresponding derivative, tetracarboxylic acid corresponding to the tetracarboxylic acid dianhydride represented by formula (a-1) (that is, nobornane-2-spiro-α-cyclopentanone-α'-spiro-2”-novo O-5,5”,6,6”-tetracarboxylic acid), and alkyl esters of the tetracarboxylic acid. As the compound that gives the structural unit (A-1), a compound represented by formula (a-1) (ie, dianhydride) is preferable.

Similarly, as the compound that gives the structural unit (A-2), a compound represented by formula (a-2) may be mentioned, but is not limited thereto, and may be a derivative thereof in a range that gives the same structural unit. . Examples of the derivatives include tetracarboxylic acids corresponding to the tetracarboxylic acid dianhydride represented by formula (a-2) and alkyl esters of the tetracarboxylic acids. As a compound that gives the structural unit (A-2), a compound represented by formula (a-2) (ie, dianhydride) is preferable.

Similarly, as the compound conferring the structural unit (A-3), a compound represented by the formula (a-3) may be mentioned, but is not limited thereto, and may be a derivative thereof within a range that gives the same structural unit. . Examples of the derivatives include tetracarboxylic acids corresponding to tetracarboxylic dianhydrides represented by formula (a-3) and alkyl esters of the tetracarboxylic acids. As a compound that gives the structural unit (A-3), a compound represented by formula (a-3) (ie, an dianhydride) is preferable.

Examples of the compound that gives the structural unit (B-1) include a compound represented by formula (b-1), but are not limited thereto, and may be derivatives thereof in the range to which the same structural unit is applied. Diisocyanate corresponding to the diamine represented by Formula (b-1) is mentioned as this derivative. As a compound that gives the structural unit (B-1), a compound represented by formula (b-1) (ie, diamine) is preferable.

The tetracarboxylic acid component preferably contains 10 to 80 mol% of the compound that gives the structural unit (A-1), more preferably 15 to 55 mol%, and even more preferably 20 to 45 mol% %, and particularly preferably 22.5 to 40 mol%.

The tetracarboxylic acid component preferably contains 10 to 80 mol% of the compound that gives the structural unit (A-2), more preferably 20 to 60 mol%, and more preferably 25 to 50 mol%. %, and particularly preferably 27.5 to 45 mol%.

The tetracarboxylic acid component preferably contains 10 to 80 mol% of the compound that gives the structural unit (A-3), more preferably 25 to 65 mol%, and even more preferably 30 to 55 mol% %, and particularly preferably 32.5 to 50 mol%.

As for the tetracarboxylic acid component, the compound that gives the structural unit (A-1), the compound that gives the structural unit (A-2), and the compound that gives the structural unit (A-3) in total, preferably 50 It contains at least mol%, more preferably at least 70 mol%, more preferably at least 90 mol%, particularly preferably at least 99 mol%. The upper limit of the total content of the compound that gives the structural unit (A-1), the compound that gives the structural unit (A-2), and the compound that gives the structural unit (A-3) is not particularly limited, that is, It is 100 mol%. The tetracarboxylic acid component may consist only of a compound that gives a structural unit (A-1), a compound that gives a structural unit (A-2), and a compound that gives a structural unit (A-3).

The tetracarboxylic acid component may contain a compound other than the compound that gives any one of the structural units (A-1) to (A to 3), and as the compound, the aromatic tetracarboxylic dianhydride, alicyclic Formula tetracarboxylic acid dianhydride, aliphatic tetracarboxylic acid dianhydride, and derivatives thereof (tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.) are mentioned.

The compound optionally included in the tetracarboxylic acid component (that is, a compound other than a compound that gives any one of the structural units (A-1) to (A to 3)) may be one type, or two or more types.

The diamine component preferably contains 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more of the compound that gives the structural unit (B-1), particularly Preferably it contains 99 mol% or more. The upper limit of the content of the compound giving the structural unit (B-1) is not particularly limited, that is, 100 mol%. The diamine component may consist of only the compound that gives the structural unit (B-1).

The diamine component may contain a compound other than the compound that gives the structural unit (B-1), and the compound may include aromatic diamines, alicyclic diamines, and aliphatic diamines, and derivatives thereof (diisocyanate, etc.). Can be mentioned.

The compound optionally included in the diamine component (that is, a compound other than the compound that gives the structural unit (B-1)) may be one type, or two or more types.

In the present invention, it is preferable that the diamine component is 0.9 to 1.1 moles per 1 mole of the tetracarboxylic acid component in the amount ratio of the tetracarboxylic acid component and the diamine component used in the production of the polyimide resin.

In addition, in the present invention, in addition to the above-described tetracarboxylic acid component and diamine component, a terminal sealant may be used for the production of the polyimide resin. As the terminal blocker, monoamines or dicarboxylic acids are preferred. As an input amount of the terminal sealing agent to be introduced, 0.0001 to 0.1 mol is preferable with respect to 1 mol of the tetracarboxylic acid component, and 0.001 to 0.06 mol is particularly preferable. Examples of the monoamine terminal blocker include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, and 3-methylbenzylamine. , 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Of these, benzylamine and aniline can be suitably used. Dicarboxylic acids are preferred as the terminal sealing agent for dicarboxylic acids, and some of them may be closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, Cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. are recommended. Of these, phthalic acid and phthalic anhydride can be suitably used.

The method for reacting the above-mentioned tetracarboxylic acid component and diamine component is not particularly limited, and a known method can be used.

As a specific reaction method, (1) a method of introducing a tetracarboxylic acid component, a diamine component, and a reaction solvent into a reactor, stirring at room temperature to 80°C for 0.5 to 30 hours, and then raising the temperature to perform an imidization reaction, ( 2) After dissolving the diamine component and the reaction solvent in a reactor, a tetracarboxylic acid component is added, and if necessary, the mixture is stirred at room temperature to 80°C for 0.5 to 30 hours, and then heated to perform an imidization reaction. And (3) a method in which a tetracarboxylic acid component, a diamine component, and a reaction solvent are introduced into a reactor, and the temperature is directly raised to perform an imidization reaction.

The reaction solvent used for the production of the polyimide resin may be any one capable of dissolving the resulting polyimide without inhibiting the imidation reaction. For example, aprotic solvents, phenol solvents, ether solvents, carbonate solvents, and the like can be given.

As specific examples of the aprotic solvent, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazoli Amide-based solvents such as dinon and tetramethyl urea, lactone-based solvents such as γ-butyrolactone and γ-valerolactone, hexamethylphosphoricamide (hexamethylphosphamide), and hexamethylphosphine triamide Phosphoric amide solvents, dimethylsulfone, dimethylsulfoxide, sulfur-containing solvents such as sulfolane, acetone, cyclohexanone, ketone-based solvents such as methylcyclohexanone, amine solvents such as picoline and pyridine, acetic acid (2- And ester-based solvents such as methoxy-1-methylethyl).

Specific examples of the phenolic solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, and 2,6 Xylenol, 3,4-xylenol, 3,5-xylenol, and the like.

As specific examples of the ether-based solvent, 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxy Ethoxyethoxy)ethyl] ether, tetrahydrofuran, 1,4-dioxane, and the like.

In addition, specific examples of the carbonate-based solvent include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

Among the reaction solvents, an amide-based solvent or a lactone-based solvent is preferable. Moreover, the said reaction solvent can also be used individually or in mixture of 2 or more types.

In the imidization reaction, it is preferable to perform the reaction while removing water generated during production using a Dean Stark apparatus or the like. By performing such an operation, the polymerization degree and the imidation rate can be further increased.

In the above imidization reaction, a known imidization catalyst can be used. A base catalyst or an acid catalyst is mentioned as an imidation catalyst.

As the base catalyst, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine , Organic base catalysts such as triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline, inorganic bases such as potassium hydroxide or sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate And catalysts.

In addition, as the acid catalyst, crotonic acid, acrylic acid, trans-3-hexenoic acid (Trans-3-3), cinnamic acid, benzoic acid, methyl benzoic acid, oxic benzoic acid, terephthalic acid, benzenesulfonic acid, paratoluenesulfonic acid, naphthalenesulf And phonic acid. The imidization catalysts may be used alone or in combination of two or more.

Among the above, from the viewpoint of handling properties, it is preferable to use a base catalyst, more preferably an organic base catalyst, more preferably triethylamine, and particularly preferably a combination of triethylamine and triethylenediamine. Do.

The temperature of the imidation reaction is preferably 120 to 250°C, more preferably 160 to 200°C, from the viewpoint of suppression of reaction rate and gelation. In addition, the reaction time is preferably 0.5 to 10 hours after the start of the outflow of generated water.

[Polyimide Varnish]

The polyimide varnish of the present invention is obtained by dissolving the polyimide resin of the present invention in an organic solvent. That is, the polyimide varnish of the present invention includes the polyimide resin and the organic solvent of the present invention, and the polyimide resin is dissolved in the organic solvent.

The organic solvent may be one in which the polyimide resin is dissolved, and is not particularly limited, but it is preferable to use the above-mentioned compound alone or in combination of two or more as a reaction solvent used in the production of the polyimide resin.

The polyimide varnish of the present invention may be a polyimide solution itself in which the polyimide resin obtained by the polymerization method is dissolved in a reaction solvent, or a dilution solvent may be further added to the polyimide solution.

Since the polyimide resin of the present invention has solvent solubility, it can be a high concentration varnish stable at room temperature. The polyimide varnish of the present invention preferably contains 5 to 40 mass% of the polyimide resin of the present invention, and more preferably 10 to 30 mass%. The viscosity of the polyimide varnish is preferably 1 to 200 Pa·s, and more preferably 5 to 150 Pa·s. The viscosity of the polyimide varnish is a value measured at 25°C using an E-type viscometer.

In addition, the polyimide varnish of the present invention, inorganic filler, adhesion promoter, release agent, flame retardant, UV stabilizer, surfactant, leveling agent, antifoaming agent, fluorescent whitening agent, crosslinking agent, to the extent that does not impair the required characteristics of the polyimide film, It may also contain various additives such as polymerization initiators and photosensitizers.

The method for producing the polyimide varnish of the present invention is not particularly limited, and a known method can be applied.

[Polyimide Film]

The polyimide film of the present invention includes the polyimide resin of the present invention. Therefore, the polyimide film of the present invention has good mechanical properties and heat resistance, and is further excellent in colorless transparency, dimensional stability to heat, laser peelability, and organic solvent resistance. The favorable physical property values of the polyimide film of the present invention are as described above.

There is no restriction|limiting in particular in the manufacturing method of the polyimide film of this invention, A well-known method can be used. For example, the polyimide varnish of the present invention is coated on a smooth support such as a glass plate, metal plate, or plastic, or molded into a film, and then heated with an organic solvent such as a reaction solvent or dilution solvent contained in the varnish. And the like. If necessary, a release agent may be previously applied to the surface of the support.

As a method of removing the organic solvent contained in the varnish by heating, the following method is preferable. That is, after the organic solvent is evaporated at a temperature of 120° C. or lower to form a self-supporting film, the self-supporting film is peeled from the support, the ends of the self-supporting film are fixed, and the temperature is higher than the boiling point of the organic solvent used It is preferred to dry in to produce a polyimide film. In addition, it is preferable to dry under a nitrogen atmosphere. The pressure of the dry atmosphere may be any of reduced pressure, normal pressure and pressurization. From the viewpoint of imparting organic solvent resistance to the polyimide film, the heating temperature when the self-supporting film is dried to produce a polyimide film is preferably 320°C or higher, and more preferably 340°C or higher. Do. The upper limit of the heating temperature is not particularly limited, but is preferably 400°C or lower.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the application and the like, but is preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and more preferably 10 to 80 μm. When the thickness is 1 to 250 μm, practical use as a freestanding film becomes possible.

The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and viscosity of the polyimide varnish.

The polyimide film of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members. The polyimide film of the present invention is particularly suitably used as a substrate for an image display device such as a liquid crystal display or an OLED display.

Example

Hereinafter, the present invention will be specifically described by examples. However, the present invention is not limited at all by these examples.

The solid content concentration of the polyimide varnish obtained in Examples and Comparative Examples and each physical property of the polyimide film were measured by the method shown below.

(1) Solid content concentration

The measurement of the solid content concentration of the polyimide varnish was performed by heating the sample at 320 DEG C x 120 min in "MMF-1" by a small electric machine manufactured by As One Corporation, and calculated from the mass difference between the samples before and after heating.

(2) Film thickness

The film thickness was measured using a micrometer manufactured by Mitsutoyo Corporation.

(3) Tensile strength, tensile modulus

The measurement was carried out in accordance with JIS K7127, and was performed using a tensile tester "Stragraph VG-1E" manufactured by Toyo Seiki Co., Ltd.

(4) Glass transition temperature (Tg)

Using the thermomechanical analysis device ``TMA/SS6100'' manufactured by Hitachi Hi-Tech Science Co., Ltd., the sample is 2mm×20mm in tension mode, the load is 0.1N, and the temperature is raised to Tg or higher under the condition of 10℃/min to remove residual stress. Then, TMA measurement was performed from 50°C to 400°C under the same conditions to obtain Tg.

(5) Total light transmittance, yellow index (YI)

The measurement was carried out in accordance with JIS K7361-1, and a color and turbidity simultaneous measuring instrument "COH400" manufactured by Nippon Electric Industries, Ltd. was used.

(6) Coefficient of thermal expansion (CTE)

Using a thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi Hi-Tech Science Co., Ltd., the TMA measurement was performed under the condition of a sample size of 2 mm x 20 mm, a load of 0.1 N, and a heating rate of 10°C/min in a tensile mode. The CTE was obtained.

(7) Light transmittance at wavelength 308 nm

It was measured using an ultraviolet visible near infrared spectrophotometer "UV-3100PC" manufactured by Shimadzu Corporation.

(8) Organic solvent resistance

The obtained film was immersed in an organic solvent for a predetermined time, and the organic solvent resistance was evaluated. On the other hand, as an organic solvent, a mixed solvent of N-methyl-2-pyrrolidone (NMP), which is a stripping solution for removing the photoresist layer, and 2-aminoethanol (mixed at a mass ratio of 1:1) was used.

The evaluation criteria of organic solvent resistance were as follows.

E: The film surface was dissolved in less than 10 minutes by immersion in an organic solvent.

D: The film surface was dissolved in 10 minutes or more and less than 20 minutes by immersion in an organic solvent.

C: The film surface was dissolved in 20 minutes or more and less than 30 minutes by immersion in an organic solvent.

B: The film surface dissolved in 30 minutes or more and less than 40 minutes by immersion in an organic solvent.

A: After immersing in an organic solvent for 40 minutes, the film surface did not dissolve and there was no change.

From a practical point of view, it is preferable that the film surface does not dissolve for 10 minutes or more and does not change, and the above evaluation E is a rejected level.

The acid dianhydride and diamine used in Examples and Comparative Examples, and their abbreviations are as follows.

<mountain dianhydride>

CpODA: Novonan-2-spiro-α-cyclopentanone-α'-spiro-2”-novonan-5,5”,6,6”-tetracarboxylic dianhydride (manufactured by JX Energy Corporation; formula (a Compound represented by -1))

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation; compound represented by formula (a-2))

HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.; compound represented by formula (a-3))

<diamine>

TFMB: 2,2'-bis(trifluoromethyl) benzidine (manufactured by Wakayama Chemical Co., Ltd.; compound represented by formula (b-1))

<Example 1>

In a 1L 5-neck round bottom flask equipped with a stainless half moon type stirring wing, nitrogen introduction tube, Dean Stark with a cooling tube, thermometer, and glass end cap, TFMB is 32.024 g (0.100 mol) and γ-butyrolactone. (Mitsubishi Chemical Co., Ltd.) was added 73.799 g, and the solution was stirred at an internal temperature of 70° C. under a nitrogen atmosphere and at a rotation speed of 200 rpm to obtain a solution.

To this solution, 11.53 g (0.030 mol) of CpODA, 8.826 g (0.030 mol) of BPDA, 8.967 g (0.040 mol) of HPMDA, and 18.450 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) are collectively. After the addition, 5.06 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) and 0.056 g of triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added as an imidization catalyst, heated with a mantle heater, and reacted within about 20 minutes. The temperature was raised to 190°C. The remaining components were collected and the temperature in the reaction system was maintained at 190°C and refluxed for 5 hours while adjusting the rotational speed to increase the viscosity.

Thereafter, 164.99 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) was added, the temperature in the reaction system was cooled to 120° C., and then stirred for about 3 hours to homogenize, and a polyimide varnish having a solid content concentration of 10% by mass was added. Got. Subsequently, the obtained polyimide varnish was applied onto a glass plate, held on a hot plate at 80° C. for 20 minutes, and then heated under a nitrogen atmosphere at 350° C. in a hot air dryer for 30 minutes to evaporate the solvent to obtain a thickness of 10 μm. A film was obtained. Table 1 shows the results.

<Example 2>

A polyimide varnish was produced in the same manner as in Example 1, except that the amount of CpODA was changed from 0.030 mol to 0.025 mol and the amount of BPDA was changed from 0.030 mol to 0.035 mol, and polyimide having a solid content concentration of 10% by mass Got a varnish. Using the obtained polyimide varnish, a film was produced in the same manner as in Example 1 to obtain a film having a thickness of 20 μm. Table 1 shows the results.

<Example 3>

A polyimide varnish was produced in the same manner as in Example 1, except that the amount of BPDA was changed from 0.030 mol to 0.035 mol, and the amount of HPMDA was changed from 0.040 mol to 0.035 mol, and polyimide having a solid content concentration of 10 mass%. Got a varnish. Using the obtained polyimide varnish, a film was produced in the same manner as in Example 1 to obtain a film having a thickness of 14 μm. Table 1 shows the results.

<Comparative Example 1>

A polyimide varnish was produced in the same manner as in Example 1, except that only 0.100 mol of CpODA was used as the acid dianhydride, to obtain a polyimide varnish having a solid content concentration of 10% by mass. Using the obtained polyimide varnish, a film was produced in the same manner as in Example 1 to obtain a film having a thickness of 14 μm. Table 1 shows the results.

<Comparative Example 2>

In a 500 mL 5-neck round bottom flask equipped with a stainless steel half moon type stirring blade, nitrogen introduction tube, Dean Stark with a cooling tube, thermometer, and glass end cap, TFMB 32.024 g (0.100 mol) and N,N-dimethyl 73.993 g of formamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added and stirred at a temperature of 50° C. under a nitrogen atmosphere and 200 rpm to obtain a solution.

To this solution, 29.420 g (0.100 mol) of BPDA and 18.498 g of N,N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were added in batch, dissolved over about 20 minutes, and the rotational speed increased to viscosity. It was stirred at room temperature for 5 hours while adjusting to time.

Thereafter, 165.442 g of N,N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added, stirred for about 1 hour, and homogenized to obtain a polyamic acid varnish having a solid content concentration of 20% by mass. Subsequently, the obtained polyamic acid varnish was applied onto a glass plate, held on a hot plate at 80°C for 20 minutes, and then heated under a nitrogen atmosphere at 350°C in a hot air dryer for 30 minutes to imidize the polyamic acid. Together, the solvent in the varnish was evaporated to obtain a film with a thickness of 7 μm. Table 1 shows the results.

<Comparative Example 3>

A polyimide varnish was produced in the same manner as in Example 1, except that only 0.100 mol of HPMDA was used as the acid dianhydride, to obtain a polyimide varnish having a solid content concentration of 10% by mass. Using the obtained polyimide varnish, a film was produced in the same manner as in Example 1 to obtain a film having a thickness of 10 μm. Table 1 shows the results.

[Table 1]

As shown in Table 1, the polyimide films of Examples 1 to 3 have good mechanical properties and heat resistance, and are further excellent in colorless transparency, heat dimensional stability, laser peelability, and organic solvent resistance.

On the other hand, in the polyimide film of Comparative Example 1, the laser peeling property was significantly inferior, and the organic solvent resistance was also a level of practical failure. The polyimide film of Comparative Example 2 is slightly inferior in colorless transparency, and its dimensional stability against heat is greatly inferior. The polyimide film of Comparative Example 3 is significantly inferior in dimensional stability to heat and laser peelability.

Claims (5)

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine,
The structural unit A is a structural unit (A-1) derived from a compound represented by the following formula (a-1), and a structural unit (A-2) derived from a compound represented by the following formula (a-2), Constituent unit (A-3) derived from a compound represented by the following formula (a-3),
The polyimide resin in which the structural unit B contains the structural unit (B-1) derived from the compound represented by the following formula (b-1).
[Formula 1]

According to claim 1,
The proportion of the structural unit (A-1) in the structural unit A is 10 to 80 mol%,
The proportion of the structural unit (A-2) in the structural unit A is 10 to 80 mol%,
The polyimide resin whose ratio of the structural unit (A-3) in the structural unit A is 10 to 80 mol%. The method according to claim 1 or 2,
The polyimide resin whose ratio of the structural unit (B-1) in the structural unit B is 50 mol% or more. A polyimide varnish comprising the polyimide resin according to any one of claims 1 to 3 dissolved in an organic solvent. A polyimide film comprising the polyimide resin according to any one of claims 1 to 3.