KR20230044202A - Polyimide resins, polyamic acids, varnishes and polyimide films - Google Patents

Abstract

(식 중, R은 각각 독립적으로, 메틸기, 또는 트리플루오로메틸기이고, n은 1~4의 정수이다.)A polyimide resin having structural unit A derived from tetracarboxylic dianhydride and structural unit B derived from diamine, wherein structural unit A contains structural unit (A1) derived from a compound represented by the following formula (a1) , A polyimide resin containing a structural unit (B1) in which the structural unit B is derived from a compound represented by the following formula (b1).

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

Description

Polyimide resins, polyamic acids, varnishes and polyimide films

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

BACKGROUND ART Polyimide resins are being examined for various uses in fields such as electric/electronic components. For example, it is desired to replace a glass substrate used in an image display device such as a liquid crystal display or an OLED display with a plastic substrate for the purpose of reducing the weight or flexibility of the device, and a polyimide film suitable as the plastic substrate research is in progress.

For example, in Patent Document 1, for the purpose of obtaining a polyimide having a low moisture absorption and expansion coefficient and a low water absorption, particularly used as an insulating film of a substrate for flexible printed wiring, polyimide obtained from ester group-containing tetracarboxylic dianhydride and diamine An esterimide precursor varnish and a polyesterimide film formed by imidizing the varnish are disclosed.

Japanese Unexamined Patent Publication No. 2014-001394

In recent years, in displays where the device type of TFT is LTPS (Low Temperature Polysilicon TFT), which is being developed with the goal of high definition of liquid crystal display or OLED display, the process temperature exceeds 400 ° C., Polyimide used as a substrate is required to have heat resistance capable of withstanding high temperatures of 400°C or higher. Furthermore, reduction of the coefficient of linear expansion is also required for the reason that peeling in the joint surface or deformation of the product is disturbed due to the difference in the coefficient of linear thermal expansion with the inorganic layer constituting the device. In addition, a new type of display is being developed due to the advancement of display technology, and, for example, in a display using a transparent display or UDC (under display camera) technology, a low yellowness is required for a substrate.

Under these circumstances, aromatic polyimide resins are excellent in heat resistance and linear expansion coefficient that withstand high temperatures, but have a problem of easy yellowing, and a polyimide film having heat resistance, low linear expansion coefficient, and low yellowness has been desired.

The present invention has been made in view of such a situation, and an object of the present invention is a polyimide resin capable of obtaining a polyimide film having a low yellowness while maintaining a low linear expansion coefficient and excellent heat resistance, a polyamide acid as a precursor thereof, It is to provide a varnish and a polyimide film.

The inventors of the present invention have discovered 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 [15].

[One]

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine, wherein the structural unit A contains a structural unit (A1) derived from a compound represented by the following formula (a1) , A polyimide resin containing a structural unit (B1) in which the structural unit B is derived from a compound represented by the following formula (b1).

[Formula 1]

(In the formula, R each independently represents a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

[2]

The polyimide resin according to [1] above, wherein the structural unit (A1) derived from a compound represented by the formula (a1) is a structural unit (A11) derived from a compound represented by the following formula (a11).

[Formula 2]

[3]

The polyimide resin according to [1] or [2] above, wherein the ratio of the structural unit (A1) in the structural unit A is 50 to 100 mol%.

[4]

The polyimide resin according to any one of [1] to [3] above, wherein the ratio of the structural unit (B1) in the structural unit B is 50 to 100 mol%.

[5]

The polyimide resin according to any one of [1] to [4] above, having a glass transition temperature (Tg) of 400°C or higher.

[6]

The polyimide resin according to any one of [1] to [5] above, wherein the yellow index (YI) at a film thickness of 10 µm is 20 or less.

[7]

A polyamic acid having a structural unit AA derived from tetracarboxylic dianhydride and a structural unit BA derived from diamine,

The structural unit AA includes a structural unit (AA1) derived from a compound represented by the following formula (a1),

A polyamic acid in which the structural unit BA contains a structural unit (BA1) derived from a compound represented by the following formula (b1).

[Formula 3]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

[8]

The polyimide acid according to [7] above, wherein the structural unit (AA1) derived from the compound represented by the formula (a1) is the structural unit (AA11) derived from the compound represented by the following formula (a11).

[Formula 4]

[9]

The polyimide acid according to the above [7] or [8], wherein the ratio of the structural unit (AA1) in the structural unit AA is 50 to 100 mol%.

[10]

The polyimide acid according to any one of [7] to [9] above, wherein the ratio of the structural unit (BA1) in the structural unit BA is 50 to 100 mol%.

[11]

A varnish obtained by dissolving the polyamic acid according to any one of [7] to [10] above in an organic solvent.

[12]

The varnish according to the above [11], further comprising a compound represented by the following formula (y1).

[Formula 5]

[13]

A polyimide film obtained by applying the varnish according to the above [11] or [12] onto a support and heating it.

[14]

A method for producing a polyimide film, wherein the varnish according to [11] or [12] is applied onto a support and heated.

[15]

A polyimide film containing the polyimide resin according to any one of the above [1] to [6].

It is an object of the present invention to provide a polyimide resin capable of obtaining a polyimide film having a low yellowness while maintaining a low linear expansion coefficient and excellent heat resistance, a polyamic acid as a precursor thereof, a varnish, and a polyimide film.

[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,

structural unit A contains a structural unit (A1) derived from a compound represented by the following formula (a1);

The structural unit B contains a structural unit (B1) derived from a compound represented by the following formula (b1).

[Formula 6]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

<Component A>

Structural unit A is a structural unit derived from tetracarboxylic dianhydride occupying a polyimide resin.

Structural unit A includes a structural unit (A1) derived from a compound represented by the following formula (a1).

[Formula 7]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

In the formula (a1), each R is independently a methyl group or a trifluoromethyl group, preferably a methyl group.

n is an integer of 1 to 4, preferably n is 3.

That is, the structural unit (A1) derived from the compound represented by the formula (a1) contains the structural unit (A11) derived from the compound represented by the following formula (a11) from the viewpoint of heat resistance and yellowness reduction. it is desirable Further, the structural unit (A1) derived from the compound represented by the formula (a1) is a structural unit (A11) derived from a compound represented by the following formula (a11) from the viewpoint of heat resistance and yellowness reduction. desirable.

[Formula 8]

The compound represented by formula (a11) is 2,2',3,3',5,5'-hexamethyl[1,1'-biphenyl]-4,4'-diyl=bis(1,3- dioxo-1,3-dihydro-2-benzofuran-5-carboxylate) (TMPBP-TME).

When structural unit A contains the structural unit derived from the compound represented by formula (a11), yellowness can also be reduced, making the film of this invention excellent heat resistance and a low linear thermal expansion coefficient.

The ratio of the structural unit (A1) in the structural unit A is preferably 40 mol% or more, more preferably 50 mol% or more, from the viewpoint of maintaining a low linear thermal expansion coefficient and reducing yellowness. is 70 mol% or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. Although the upper limit of the ratio is not particularly limited, it is 100 mol% or less. The ratio of the structural unit (A1) in the structural unit A may be 100 mol%, and it is preferable that the structural unit A consists only of the structural unit (A1).

When a structural unit (A11) derived from a compound represented by formula (a11) is included as the structural unit (A1), the proportion of the structural unit (A11) in the structural unit A is preferably 40 mol% or more, , More preferably, it is 50 mol% or more, still more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. Although the upper limit of the ratio is not particularly limited, it is 100 mol% or less. The ratio of structural unit (A11) in structural unit A may be 100 mol%, and it is preferable that structural unit A consists only of structural unit (A11).

When structural unit A contains the structural unit derived from the compound represented by formula (a11) within the said range, yellowness can also be reduced, making the film of this invention excellent heat resistance and a low linear thermal expansion coefficient.

Structural unit A may also contain structural units other than structural unit (A1) within the range which does not impair the effect of this invention. The tetracarboxylic acid dianhydride giving such a structural unit is not particularly limited, but p-phenylene bis(trimellitate) anhydride (TAHQ), which is a compound represented by the following formula (a2), and the following formula (a3) 4,4'-bis(1,3-dioxobenzofuran-5-ylcarbonyloxy)biphenyl (BP-TME) as a compound represented by 9,9-bis as a compound represented by the following formula (a4) (3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF), pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoro Isopropylidene) diphthalic anhydride, 3,3',4,4'-diphenylsulfotetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2', aromatic tetracarboxylic acid dianhydrides such as 3,3'-benzophenone tetracarboxylic acid dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo [2.2.2] octa-7-ene-2,3,5,6-tetracarboxylic dianhydride, and dicyclohexyltetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α' alicyclic tetracarboxylic acid dianhydrides such as -spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid dianhydride; and aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride, among these, preferably aromatic tetracarboxylic dianhydride, more preferably the following formula (a2 ) p-phenylene bis (trimellitate) anhydride (TAHQ), a compound represented by 4,4'-bis (1,3-dioxobenzofuran-5-yl, a compound represented by the following formula (a3)) It is selected from the group consisting of carbonyloxy) biphenyl (BP-TME) and 9,9-bis (3,4-dicarboxyphenyl) fluorene diacid anhydride (BPAF), which is a compound represented by the following formula (a4) At least one, and from the viewpoint of stretching, more preferably p-phenylenebis(trimellitate) anhydride (TAHQ), which is a compound represented by the following formula (a2), and 4 compounds represented by the following formula (a3) At least one selected from the group consisting of 4'-bis(1,3-dioxobenzofuran-5-ylcarbonyloxy)biphenyl (BP-TME), and from the viewpoint of strength and elongation, more preferably is p-phenylenebis(trimellitate) anhydride (TAHQ), which is a compound represented by the following formula (a2).

[Formula 9]

p-phenylenebis(trimellitate) anhydride (TAHQ), which is the compound represented by the formula (a2), and 4,4'-bis(1,3-dioxobenzofuran, which is the compound represented by the formula (a3)) -5-ylcarbonyloxy)biphenyl (BP-TME) and 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF), which is a compound represented by the formula (a4) A structural unit derived from at least one compound selected from the group is used as the structural unit (A2).

When the structural unit A contains the structural unit (A2), the ratio of the structural unit (A2) in the structural unit A is preferably 1 to 60 mol% from the viewpoint of maintaining a low linear thermal expansion coefficient and low yellowness. , more preferably 10 to 50 mol%, still more preferably 10 to 30 mol%.

Structural units other than the structural unit (A1) arbitrarily included in the structural unit A may be one kind or two or more kinds.

Meanwhile, in the present specification, aromatic tetracarboxylic acid dianhydride means tetracarboxylic acid dianhydride containing one or more aromatic rings, and alicyclic tetracarboxylic acid dianhydride includes one or more alicyclic rings, and also aromatic rings. It means a tetracarboxylic acid dianhydride that does not contain, and the aliphatic tetracarboxylic acid dianhydride means a tetracarboxylic acid dianhydride that does not contain an aromatic ring or an alicyclic ring.

<Component B>

The structural unit B includes a structural unit (B1) derived from a compound represented by the following formula (b1).

It is considered that, by including the structural unit (B1), the structural unit B has excellent heat resistance, a low linear thermal expansion coefficient, and excellent thermal physical properties, but also has a low yellowness, high colorlessness, and low residual stress. .

[Formula 10]

The compound represented by formula (b1) is 4-aminophenyl-4'-aminobenzoate (4-BAAB).

The ratio of the structural unit (B1) in the structural unit B is preferably 50 mol% or more, more preferably 70 mol%, from the viewpoint of improving low yellowness, low residual stress, low linear thermal expansion coefficient, and heat resistance. % or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, and is 100 mol% or less. The ratio of the structural unit (B1) in the structural unit B may be 100 mol%, and it is preferable that the structural unit B consists only of the structural unit (B1).

The structural unit B may also contain structural units other than the structural unit (B1).

The diamine giving such a structural unit is not particularly limited, but 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA) which is a compound represented by the following formula (b2) ), 4,4'-diaminodiphenyl ether, 9,9-bis (4-aminophenyl) fluorene, 2,2'-bis (trifluoromethyl) benzidine, 1,4-phenylenediamine, p -xylylenediamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 1, 4-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenylsulfone, 3,4' -Diaminodiphenyl ether, 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, 2,2-bis(3-amino-4-hydroxyphenyl)hexa aromatic diamines such as fluoropropane and 1,4-bis(4-aminophenoxy)benzene; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine. Among these, aromatic diamines are preferred, and 2,2'-bis(trifluoro methyl)-4,4'-diaminodiphenyl ether (6FODA).

[Formula 11]

A structural unit derived from 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA), which is the compound represented by the formula (b2), is designated as the structural unit (B2).

When the structural unit B contains the structural unit (B2), the ratio of the structural unit (B2) in the structural unit B is preferably 1 to 50 mol%, more preferably 10 to 50 mol%, from the viewpoint of transparency. 30 mol%.

Meanwhile, in the present specification, aromatic diamine means diamine containing one or more aromatic rings, and alicyclic diamine means diamine containing one or more alicyclic rings and not containing aromatic rings. Aliphatic diamine means diamine containing one or more alicyclic rings. It means diamine containing neither an aromatic ring nor an alicyclic ring.

Structural units other than the structural unit (B1) arbitrarily included in the structural unit B may be one kind or two or more kinds.

The polyimide resin of the present invention may also contain structures other than the polyimide chain (a structure formed by imide bonding of structural units A and B). Examples of structures other than the polyimide chain that can be contained in the polyimide resin include structures containing an amide bond.

The polyimide resin of the present invention preferably contains a polyimide chain (a structure formed by imide bonding of structural units A and B) as a main structure. Therefore, the proportion of the polyimide chain in the polyimide resin of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably It is 99 mass % or more and may be 100 mass %.

By using the polyimide resin of the present invention, a film with low yellowness can be formed while maintaining a low linear expansion coefficient and excellent heat resistance. Suitable physical property values of the polyimide resin of the present invention are as follows. On the other hand, the physical property values at a film thickness of 10 μm below are the physical property values when the polyimide resin of the present invention is molded into a film having a thickness of 10 μm.

The total light transmittance at a film thickness of 10 μm is preferably 80% or more, more preferably 83% or more, still more preferably 85% or more.

The yellow index (YI) at a film thickness of 10 µm is preferably 20 or less, more preferably 15 or less, still more preferably 12 or less.

The coefficient of linear expansion (CTE) is in the range of 100-400°C, preferably 25 ppm/°C or less, more preferably 23 ppm/°C or less, 20 ppm/°C or less, still more preferably 18 ppm/°C or less.

The glass transition temperature (Tg) is preferably 400°C or higher, more preferably 420°C or higher, still more preferably 430°C or higher.

On the other hand, the above-mentioned physical property values in the present invention can be specifically measured by the method described in Examples.

[Polyamic acid, method for producing polyamic acid, and method for producing polyimide resin]

The polyimide resin of the present invention can be produced by reacting a tetracarboxylic acid component containing the compound imparting the structural unit A described above with a diamine component containing the compound imparting the structural unit (B1) described above. there is.

It is preferable to manufacture the polyimide resin of this invention by the method of imidating (dehydration ring closure) the polyamic acid which is a precursor of the said polyimide resin. Specifically, it is preferable to obtain a polyimide resin by applying or molding a polyamic acid contained in a varnish described later on a support, removing the organic solvent by heating, and imidating (dehydration ring closure) by heating. Production of the polyimide film, which is a film-like polyimide resin, will be described later. On the other hand, polyamic acid is a product of polyaddition reaction between the above-mentioned tetracarboxylic acid component and the above-mentioned diamine component.

That is, the polyamic acid used as a precursor of the polyimide resin of the present invention is a polyamic acid having a structural unit AA derived from tetracarboxylic dianhydride and a structural unit BA derived from diamine, wherein the structural unit AA is represented by the following formula ( It is preferable that it is a polyamic acid containing the structural unit (AA1) derived from the compound represented by a1), and structural unit BA containing the structural unit (BA1) derived from the compound represented by the following formula (b1).

[Formula 12]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.)

In the formula (a1), each R is independently a methyl group or a trifluoromethyl group, preferably a methyl group.

n is an integer of 1 to 4, preferably n is 3.

Among the compounds (tetracarboxylic acid component) that give the structural unit A in the polyimide of the present invention, a compound represented by formula (a1), which is a compound that gives the structural unit (A1) described above, as a preferable compound. However, it is not limited thereto, and may be a derivative thereof within the scope of giving the same structural unit. Examples of the derivative include tetracarboxylic acid corresponding to tetracarboxylic dianhydride represented by formula (a1) and alkyl esters of the tetracarboxylic acid. As a compound which gives structural unit (A1), the compound represented by formula (a1) (ie, dianhydride) is preferable.

Especially, the compound represented by formula (a11) is more preferable.

The tetracarboxylic acid component may also contain compounds other than the compound providing the structural unit (A1), and the compounds include the above-mentioned aromatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, and aliphatic tetracarboxylic acid dianhydride. carboxylic acid dianhydrides, and derivatives thereof (tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.).

Among them, as the compound other than the compound giving the structural unit (A1), preferably aromatic tetracarboxylic dianhydride, more preferably p-phenylene bis(trimellitate) which is a compound represented by formula (a2) ) Anhydride (TAHQ), 4,4'-bis (1,3-dioxobenzofuran-5-ylcarbonyloxy) biphenyl (BP-TME), which is a compound represented by formula (a3), and formula (a4 ) is at least one selected from the group consisting of 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF), which is a compound represented by

1 type or 2 or more types of compounds other than the compound which gives the structural unit (A1) arbitrarily contained in the tetracarboxylic acid component may be sufficient as it.

The tetracarboxylic acid component (acid dianhydride component) contains a compound that provides the structural unit (A1), and the proportion of the compound that provides the structural unit (A1) in the tetracarboxylic acid component is preferably 40 mol%. or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, and is 100 mol% or less. The ratio of the compound giving the structural unit (A1) in the tetracarboxylic acid component may be 100 mol%, and it is preferable that the tetracarboxylic acid component consists only of the compound giving the structural unit (A1).

When the compound represented by formula (a11) is included as the tetracarboxylic acid component (a compound giving structural unit (A11)), the ratio of the compound represented by formula (a11) in the tetracarboxylic acid component is preferably is 40 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 99 mol% or more. Although the upper limit of the ratio is not particularly limited, it is 100 mol% or less. The proportion of the compound represented by the formula (a11) in the tetracarboxylic acid component may be 100 mol%, and the tetracarboxylic acid component preferably consists only of the compound represented by the formula (a11).

When the tetracarboxylic acid component contains the compound represented by formula (a11) within the above range, the yellowness can be reduced while the film of the present invention has excellent heat resistance and low linear thermal expansion coefficient.

p-phenylenebis(trimellitate) anhydride (TAHQ), which is the compound represented by the formula (a2), and 4,4'-bis(1,3-dioxobenzofuran, which is the compound represented by the formula (a3)) -5-ylcarbonyloxy)biphenyl (BP-TME) and 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF), which is a compound represented by the formula (a4) A structural unit derived from at least one compound selected from the group is used as the structural unit (A2).

The tetracarboxylic acid component may contain a compound giving the structural unit (A2), and when the tetracarboxylic acid component contains a compound giving the structural unit (A2), the structural unit in the tetracarboxylic acid component ( The ratio of the compound giving A2) is preferably 1 to 60 mol%, more preferably 10 to 50 mol%, still more preferably 10 to 50 mol%, from the viewpoint of maintaining a low linear thermal expansion coefficient and achieving a low degree of yellowness. 30 mol%.

Among the compounds (diamine component) that impart the structural unit B in the polyimide of the present invention, examples of the compound imparting the structural unit (B1) include compounds represented by formula (b1), but are not limited thereto. and may be derivatives thereof within the scope of giving the same structural units. Examples of the derivative include diisocyanate corresponding to the compound represented by formula (b1). As a compound which gives structural unit (B1), the compound represented by formula (b1) (namely, diamine) is preferable.

The diamine component may contain compounds other than the compound that provides the structural unit (B1), and examples of the compound include the above-mentioned aromatic diamines, alicyclic diamines, and aliphatic diamines, and diisocyanates corresponding to them. can

Among them, aromatic diamine is preferred, and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA), which is a compound represented by formula (b2), is more preferred. .

The diamine component is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% of the compound giving the structural unit (B1). more than % The upper limit of the ratio is not particularly limited, and is 100 mol% or less. 100 mol% may be sufficient as the ratio of the compound which provides structural unit (B1) in a diamine component, and it is preferable that a diamine component consists only of the compound which provides structural unit (B1).

A structural unit derived from 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA), which is the compound represented by the formula (b2), is designated as the structural unit (B2).

The diamine component may contain a compound that imparts the structural unit (B2), and when the diamine component contains a compound that imparts the structural unit (B2), the compound that imparts the structural unit (B2) in the diamine component. The ratio of is preferably 1 to 50 mol%, more preferably 10 to 30 mol%, from the viewpoint of transparency.

On the other hand, the compound giving the structural unit AA in the polyamic acid described above is the same as the compound giving the structural unit A in the polyimide of the present invention described in the present section, and the preferred compound and ratio are the same, and the above The compounds giving the structural unit BA in the polyamic acid described above have the same preferred compounds and ratios as the compounds giving the structural unit B in the polyimide of the present invention described in this section.

In the present invention, the addition ratio of the tetracarboxylic acid component and the diamine component used in the production of the polyimide resin is preferably 0.9 to 1.1 moles of the diamine component per 1 mole of the tetracarboxylic acid component, and more preferably 0.95 to 1.10 moles. And, it is more preferably 1.00 to 1.08 moles, and even more preferably 1.01 to 1.08 moles. Since the stability of polyamic acid can be improved by setting it as the said input amount ratio, it is preferable.

In addition, in the present invention, in addition to the tetracarboxylic acid component and the diamine component described above, an end capping agent can also be used for the production of the polyimide resin. As the end capping agent, monoamines or dicarboxylic acids are preferable. The amount of the end capping agent to be introduced is preferably 0.0001 to 0.1 mol, particularly preferably 0.001 to 0.06 mol, per 1 mol of the tetracarboxylic acid component. Examples of the monoamine endcapping agent include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine , 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc. are recommended. Among these, benzylamine and aniline can be used conveniently. As the dicarboxylic acid endcapping agent, dicarboxylic acids are preferable, and some of them may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid and the like are recommended. Among these, phthalic acid and phthalic anhydride can be used conveniently.

There is no particular restriction on the method of reacting the above-mentioned tetracarboxylic acid component and diamine component for obtaining polyamic acid, and a known method can be used.

As a specific reaction method, a method in which a tetracarboxylic acid component, a diamine component, and a solvent are introduced into a reactor and stirred at 0 to 120°C, preferably 5 to 80°C for 1 to 72 hours can be exemplified.

When the reaction is carried out at 80°C or lower, the molecular weight of the polyamic acid obtained is less likely to fluctuate depending on the temperature history during polymerization, and the progress of thermal imidation can be suppressed, so that the polyamic acid is stable. can be manufactured with

The solvent used for production of the polyamic acid may be any solvent capable of dissolving the resulting polyamic acid. Examples thereof include aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents.

Specific examples of the aprotic solvent include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazoli Amide-based solvents such as dinon and tetramethylurea, lactone-based solvents such as γ-butyrolactone and γ-valerolactone, phosphorus-containing amide-based solvents such as hexamethylphosphoricamide and hexamethylphosphinetriamide, and dimethylsulfone. , Sulfur-containing solvents such as dimethyl sulfoxide and sulfolane, ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone and methylcyclohexanone, and ester solvents such as acetic acid (2-methoxy-1-methylethyl) etc. can be mentioned.

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

Specific examples of the ether solvent include 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethyl) ether, oxyethoxy) ethyl] ether, tetrahydrofuran, 1,4-dioxane, and the like.

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

Among the above reaction solvents, amide-based solvents or lactone-based solvents are preferred, amide-based solvents are more preferred, and N-methyl-2-pyrrolidone is still more preferred. These reaction solvents may be used alone or in combination of two or more.

By the above method, a polyamic acid solution containing polyamic acid dissolved in a solvent is obtained.

The concentration of the polyamic acid in the resulting polyamic acid solution is usually 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 10 to 30% by mass in the polyamic acid solution.

The number average molecular weight of the polyamic acid is preferably 5,000 to 300,000 from the viewpoint of mechanical strength of the resulting polyimide film. On the other hand, the number average molecular weight of polyamic acid can be obtained from standard polymethyl methacrylate (PMMA) conversion values measured by gel filtration chromatography, for example.

The polyamic acid obtained as described above is a polyamic acid having a structural unit AA derived from tetracarboxylic dianhydride and a structural unit BA derived from diamine, wherein the structural unit AA is represented by the formula (a1) It is preferable that the structural unit BA include the structural unit (BA1) derived from the compound represented by the formula (b1).

The structural unit (AA1) derived from the compound represented by the formula (a1) preferably contains the structural unit (AA11) derived from the compound represented by the formula (a11) from the viewpoint of heat resistance and yellowness reduction. do. Further, the structural unit (AA1) derived from the compound represented by the formula (a1) is further a structural unit (AA11) derived from the compound represented by the formula (a11) from the viewpoint of heat resistance and yellowness reduction. desirable.

The ratio of the structural unit (AA1) in the structural unit AA is preferably 40 mol% or more, more preferably 50 mol% or more, from the viewpoint of maintaining a low linear thermal expansion coefficient and reducing yellowness. is 70 mol% or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. Although the upper limit of the ratio is not particularly limited, it is 100 mol% or less. The proportion of the structural unit (AA1) in the structural unit AA may be 100 mol%, and the structural unit A preferably consists only of the structural unit (AA1).

When the structural unit (AA1) contains the structural unit (AA11) derived from the compound represented by formula (a11), the proportion of the structural unit (AA11) in the structural unit A is preferably 40 mol% or more, , More preferably, it is 50 mol% or more, still more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. Although the upper limit of the ratio is not particularly limited, it is 100 mol% or less. The proportion of the structural unit (AA11) in the structural unit AA may be 100 mol%, and the structural unit AA is preferably composed only of the structural unit (AA11).

When the structural unit AA includes a structural unit derived from a compound represented by formula (a11) within the above range, the yellowness can be reduced while the film of the present invention has excellent heat resistance and low linear thermal expansion coefficient.

The ratio of the structural unit (BA1) in the structural unit BA is preferably 50 mol% or more, more preferably 70 mol%, from the viewpoint of improving low yellowness, low residual stress, low linear thermal expansion coefficient, and heat resistance. % or more, more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, and is 100 mol% or less. The proportion of the structural unit (BA1) in the structural unit BA may be 100 mol%, and the structural unit BA is preferably composed only of the structural unit (BA1).

[Varnish]

The varnish of the present invention is formed by dissolving the polyamic acid described above, which is a precursor of the polyimide resin of the present invention, in an organic solvent. That is, the varnish of the present invention contains polyamic acid, which is a precursor of the polyimide resin of the present invention, and an organic solvent, and the polyamic acid is dissolved in the organic solvent.

The organic solvent may be one in which polyamic acid is dissolved, and is not particularly limited, but it is preferable to use the above-mentioned compounds alone or in a mixture of two or more as the solvent used for producing polyamic acid.

The varnish of the present invention may be the above-described polyamic acid solution itself, or may be a polyamic acid solution in which a diluting solvent is further added.

The varnish of the present invention may further contain an imidation catalyst and a dehydration catalyst from the viewpoint of efficiently advancing imidation of the polyamic acid of the present invention. As the imidation catalyst, any imidation catalyst having a boiling point of 40°C or more and 180°C or less is sufficient, and an amine compound having a boiling point of 180°C or less is mentioned as a preferable one. If the imidation catalyst has a boiling point of 180° C. or lower, there is no fear that the film is colored and the appearance is damaged during drying at a high temperature after film formation. In addition, if the imidation catalyst has a boiling point of 40°C or higher, the possibility of volatilization before sufficiently imidation can be avoided.

Pyridine or picoline is mentioned as an amine compound suitably used as an imidation catalyst. The imidation catalyst may be used alone or in combination of two or more.

Examples of the dehydration catalyst include acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride; carbodiimide compounds such as dicyclohexylcarbodiimide; etc. can be mentioned. You may use these individually or in combination of 2 or more types.

Since the polyamic acid contained in the varnish of the present invention has solvent solubility, a high-concentration varnish stable at room temperature can be obtained. It is preferable that the varnish of this invention contains 3-40 mass % of polyamic acid, and it is more preferable that it contains 5-30 mass %. The viscosity of the varnish is preferably 0.1 to 100 Pa·s, and more preferably 0.1 to 20 Pa·s. The viscosity of the varnish is a value measured at 25°C using an E-type viscometer.

In addition, the varnish of the present invention contains an inorganic filler, an adhesion promoter, a release agent, a flame retardant, a UV stabilizer, a surfactant, a leveling agent, an antifoaming agent, an optical whitening agent, a crosslinking agent, and a polymerization initiator within a range that does not impair the required properties of the polyimide film. , various additives such as photosensitizers may be included.

The varnish of the present invention is an optional additive, especially from the viewpoint of reducing the linear expansion coefficient, preferably further contains tetraalkoxysilane, and more preferably further contains a compound represented by the following formula (y1) .

[Formula 13]

In short, the varnish of the present invention preferably contains polyamic acid, which is a precursor of the polyimide resin of the present invention, tetraalkoxysilane, and an organic solvent, and the polyamic acid and tetraalkoxysilane are dissolved in the organic solvent. . The varnish of the present invention more preferably contains a polyamic acid, which is a precursor of the polyimide resin of the present invention, a compound represented by the above formula (y1), and an organic solvent, and contains the polyamic acid and the above formula (y1) The indicated compounds are dissolved in the corresponding organic solvent.

The compound represented by the formula (y1) is tetraethoxysilane.

Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane (a compound represented by the formula (y1)), tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane. At least one selected from the group consisting of silane, tetraethoxysilane (a compound represented by the formula (y1)) and tetraisopropoxysilane is preferable, and tetramethoxysilane and tetraethoxysilane (a compound represented by the formula (y1)) At least one selected from the group consisting of) is more preferable, and tetraethoxysilane (the compound represented by the formula (y1)) is still more preferable.

By including the tetraalkoxysilane, preferably the compound represented by the above formula (y1), the polyimide film produced using the varnish of the present invention can be reduced in yellowness while maintaining a low linear expansion coefficient and excellent heat resistance. can Among them, the coefficient of linear expansion can be greatly reduced.

When the varnish of the present invention contains tetraalkoxysilane, the amount of tetraalkoxysilane is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, based on 100 parts by mass of polyamic acid, More preferably, it is 3-15 mass parts, More preferably, it is 5-12 mass parts.

When the varnish of the present invention contains the compound represented by the formula (y1), the amount of the compound represented by the formula (y1) is preferably 1 to 30 parts by mass relative to 100 parts by mass of polyamic acid. , It is more preferably 2 to 20 parts by mass, still more preferably 3 to 15 parts by mass, and still more preferably 5 to 12 parts by mass.

The manufacturing method of the varnish of this invention is not specifically limited, A well-known method can be applied.

[Polyimide film and manufacturing method of polyimide film]

The polyimide film of the present invention contains the polyimide resin of the present invention. That is, it has structural unit A derived from tetracarboxylic dianhydride and structural unit B derived from diamine, and structural unit A contains structural unit (A1) derived from the compound represented by the formula (a1), Unit B includes a polyimide resin containing a structural unit (B1) derived from a compound represented by the formula (b1). Moreover, it is preferable that the polyimide film of this invention consists substantially of the polyimide resin of this invention. Therefore, the polyimide film of the present invention has a low yellowness while maintaining a low linear expansion coefficient and excellent heat resistance. Suitable physical property values of the polyimide film of the present invention are as described above.

The polyimide film of the present invention is preferably produced using a varnish obtained by dissolving the polyamic acid described above in an organic solvent. Further, the polyimide film of the present invention is more preferably produced using a varnish in which the above-mentioned polyamic acid is dissolved in an organic solvent and contains tetraalkoxysilane, and the above-mentioned polyamic acid is dissolved in an organic solvent. , It is more preferable to prepare using a varnish containing the compound represented by the formula (y1).

The method for producing a polyimide film using the varnish of the present invention is not particularly limited, and a known method can be used. Among them, a method of applying the varnish of the present invention on a support and then heating is preferable. Specifically, after applying the varnish of the present invention on a smooth support such as a glass plate, metal plate, or plastic, or molding it into a film form, , Organic solvents such as reaction solvents and diluents contained in the varnish are removed by heating to obtain a polyamic acid film, and the polyamic acid in the polyamic acid film is imidized (dehydration ring closure) by heating, Then, a polyimide film can be manufactured by peeling from a support body.

In this way, the polyimide film of the present invention is preferably obtained by applying the varnish of the present invention on a support and heating it.

The heating temperature when drying the polyamic acid varnish (varnish containing polyamic acid) to obtain a polyamic acid film is preferably 50 to 150°C. The heating temperature when imidizing the polyamic acid by heating is preferably 350 to 450°C, more preferably 380 to 420°C. The heating time is usually 1 minute to 6 hours, preferably 5 minutes to 2 hours, and more preferably 15 minutes to 1 hour. By setting it as such temperature and time, the physical properties of the polyimide film obtained become favorable.

The heating atmosphere includes air gas, nitrogen gas, oxygen gas, hydrogen gas, nitrogen/hydrogen mixed gas, and the like. In order to suppress coloring of the obtained polyimide resin, nitrogen gas having an oxygen concentration of 100 ppm or less and a hydrogen concentration of 0.5 A nitrogen/hydrogen mixed gas containing less than % is preferred.

On the other hand, the method of imidation is not limited to thermal imidation, and chemical imidation can also be applied.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the application and the like, and is preferably in the range of 1 to 250 μm, more preferably in the range of 5 to 100 μm, and still more preferably in the range of 7 to 50 μm. When the thickness is 1 to 250 μm, practical use as a self-supporting film becomes possible.

The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and viscosity of the 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 this invention is used especially suitably as a board|substrate of image display apparatuses, such as a liquid crystal display and an OLED display.

Among them, the polyimide film of the present invention is excellent in heat resistance and can be suitably used for LTPS-TFT (low-temperature polysilicon TFT) substrates requiring a high process temperature. That is, the polyimide film of the present invention is preferably a polyimide film for LTPS-TFT (low-temperature polysilicon TFT) substrates. The LTPS-TFT (low-temperature polysilicon TFT) substrate containing the polyimide film of the present invention is composed of a laminate in which the polyimide film and at least one selected from the group consisting of a metal film layer, a semiconductor film layer, and an insulating film layer are laminated. . Since the LTPS-TFT (low-temperature polysilicon TFT) substrate includes the polyimide film of the present invention, it has excellent transparency. That is, the LTPS-TFT (low temperature polysilicon TFT) substrate is suitable for a transparent display or a display using UDC (under display camera) technology. In addition, the polyimide film of the present invention is suitable for a LTPS-TFT (low temperature polysilicon TFT) substrate used for a display using a transparent display or UDC (under display camera) technology.

Example

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

<Film properties and evaluation>

Physical properties and evaluation of the films obtained in Examples and Comparative Examples were measured and evaluated by the methods shown below. These results are shown in Table 1.

(1) Film thickness

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

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

The total light transmittance and YI were measured in accordance with JIS K7136 and YI ASTM E313-05 (D light source, 65°) using a color/turbidity simultaneous measuring instrument "COH7700" manufactured by Nippon Denshoku Kogyo Co., Ltd.

(3) Glass transition temperature (Tg)

Using a thermomechanical analyzer "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., in the tensile mode, the sample size was 3 mm × 20 mm, the load was 20 mN, under nitrogen flow (flow rate 200 mL / min), and the heating rate was 10 ° C / min. , The temperature was raised from 40°C to 550°C, the elongation of the test piece was measured, and the glass transition temperature was obtained by extrapolation of the inflection point of the elongation.

(4) Coefficient of linear thermal expansion (CTE)

Using a thermomechanical analyzer "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., TMA measurement was performed by raising the temperature from 40 °C to 550 °C under the conditions of a sample size of 3 mm × 20 mm, a load of 20 mN, and a heating rate of 10 °C/min in tensile mode. was performed and the CTE at 100 to 400°C was obtained.

(5) 5% weight reduction temperature (Td 5%)

A differential thermal thermogravimetric simultaneous measuring device "TG/DTA6200" manufactured by Hitachi High-Tech Sciences Co., Ltd. was used. The temperature of the sample was raised to 40 to 550°C at a heating rate of 10°C/min, and compared with the weight at 300°C, the temperature at which the weight decreased by 1% was defined as the 1% weight loss temperature. The weight loss temperature is excellent as the number increases.

(6) Tensile strength, tensile modulus of elasticity, elongation

Tensile strength, tensile modulus of elasticity, and elongation were measured in accordance with JIS K7127:1999 using a tensile tester "Strograph VG-1E" manufactured by Toyo Seiki Co., Ltd. The distance between chucks was 50 mm, the size of the specimen was 10 mm × 70 mm, and the test speed was 20 mm/min.

The tetracarboxylic acid component and diamine component used in Examples and Comparative Examples, and their abbreviations, etc. are as follows.

<Tetracarboxylic acid component>

TMPBP-TME: (manufactured by Honshu Chemical Industry Co., Ltd.; compound represented by formula (a11))

TAHQ: p-phenylenebis(trimelitate) anhydride (manufactured by Manac Co., Ltd., compound represented by formula (a2))

BP-TME: (manufactured by Honshu Chemical Industry Co., Ltd.; compound represented by formula (a3))

s-BPDA: 3,3',4,4'-biphenyl tetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation)

<Diamine component>

4-BAAB: 4-aminophenyl-4-aminobenzoate (manufactured by Nippon Sunryang Chemical Co., Ltd.; compound represented by formula (b1))

6FODA: 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (manufactured by ChinaTech (Tianjin) Chemical Co., Ltd., compound represented by formula (b2))

The symbol of the solvent used in Examples and Comparative Examples is as follows.

NMP: N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation)

The symbol of the additive used in the Example, etc. are as follows.

TEOS: tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd., a compound represented by formula (y1))

Example 1

10.107 g (0.044 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 27.393 g (0.044 mol) of TMPBP-TME and 42.500 g of NMP were charged at once, and the mixture was maintained at an internal temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

Subsequently, the obtained polyamic acid varnish was applied on a glass plate by spin coating, held at 80°C for 20 minutes on a hot plate, and then heated in a nitrogen atmosphere at 400°C in a hot air dryer for 60 minutes (heating rate 5°C/min), the solvent was evaporated, and further thermal imidation was carried out to obtain a polyimide film. The results are shown in Table 1.

Example 2

7.885 g (0.035 mol) of 4-BAAB, 2.904 g (0.009 mol) of 6FODA in a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap ) and 170.000 g of NMP were added, the temperature was raised to 80° C. in the system using a mantle heater, and stirring was performed at a rotation speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 26.711 g (0.043 mol) of TMPBP-TME and 42.500 g of NMP were charged at once, and the mixture was maintained at an internal temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 3

10.636 g (0.047 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL five-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 14.412 g (0.023 mol) of TMPBP-TME, 12.452 g (0.023 mol) of BP-TME, and 42.500 g of NMP were charged at once, and the mixture was maintained at a system temperature of 80° C. for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 4

11.164 g (0.049 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 15.128 g (0.024 mol) of TMPBP-TME, 11.209 g (0.024 mol) of TAHQ, and 42.500 g of NMP were charged at once, and the mixture was maintained at a system temperature of 80° C. for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 5

10.312 g (0.045 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 22.358 g (0.036 mol) of TMPBP-TME, 4.829 g (0.009 mol) of BP-TME, and 42.500 g of NMP were added at once, and maintained at a system temperature of 80° C. for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 6

10.505 g (0.046 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet pipe, a Dean Stark equipped with a cooling pipe, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 22.776 g (0.037 mol) of TMPBP-TME, 4.219 g (0.009 mol) of TAHQ, and 42.500 g of NMP were added at once, and the mixture was maintained at a system temperature of 80° C. for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 7

10.472 g (0.046 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 27.028 g (0.044 mol) of TMPBP-TME and 42.500 g of NMP were charged at once, and the mixture was maintained at a system temperature of 80° C. for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 8

10.543 g (0.046 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 26.957 g (0.044 mol) of TMPBP-TME and 42.500 g of NMP were charged at once, and the mixture was maintained at an internal temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Example 9

TEOS was added to 100 g of the polyamic acid varnish having a solid content concentration of 15 mass% obtained in Example 1 so that 10 parts by mass of TEOS was added to 100 parts by mass of polyamic acid, and the mixture was stirred and homogenized for 30 minutes to obtain a varnish.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Comparative Example 1

11.223 g (0.049 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 26.277 g (0.049 mol) of BP-TME and 42.500 g of NMP were charged at once, and the mixture was held at an internal temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Comparative Example 2

16.383 g (0.072 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 21.117 g (0.072 mol) of s-BPDA and 42.500 g of NMP were charged at once, and the mixture was maintained at a system temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

Comparative Example 3

12.467 g (0.055 mol) of 4-BAAB and 170.000 g of NMP were added to a 300 mL 5-necked round bottom flask equipped with a stainless steel half-moon-shaped stirring blade, a nitrogen inlet tube, a Dean Stark equipped with a cooling tube, a thermometer, and a glass end cap. , The system temperature was raised to 80 ° C. with a mantle heater, and the mixture was stirred at a rotational speed of 200 rpm under a nitrogen atmosphere to obtain a solution.

To this solution, 25.033 g (0.055 mol) of TAHQ and 42.500 g of NMP were charged at once, and the mixture was held at an internal temperature of 80°C for 10 minutes. After confirming the dissolution, the mixture was cooled to 25°C and stirred at 25°C for 5 hours to obtain a polyamic acid varnish having a solid content concentration of 15% by mass.

A film was obtained by the same method as in Example 1 using the obtained varnish.

[Table 1]

As can be seen from the results shown in Table 1, the polyimide film containing the polyimide resin of the present invention is a film made of an aromatic polyimide resin having excellent heat resistance and a low linear expansion coefficient, but has a low yellowness and yellowing. this is suppressed.

On the other hand, as can be seen from Example 9, when TEOS is used as an additive, it can be seen that a particularly low coefficient of linear expansion is exhibited.

Claims (15)

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine,
structural unit A contains a structural unit (A1) derived from a compound represented by the following formula (a1);
A polyimide resin in which the structural unit B contains a structural unit (B1) derived from a compound represented by the following formula (b1).
[Formula 1]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.) According to claim 1,
The structural unit (A1) derived from the compound represented by the said formula (a1) is a structural unit (A11) derived from the compound represented by the following formula (a11), polyimide resin.
[Formula 2]

According to claim 1 or 2,
The polyimide resin whose ratio of the structural unit (A1) in structural unit A is 50-100 mol%. According to any one of claims 1 to 3,
The polyimide resin whose ratio of the structural unit (B1) in structural unit B is 50-100 mol%. According to any one of claims 1 to 4,
A polyimide resin having a glass transition temperature (Tg) of 400° C. or higher. According to any one of claims 1 to 5,
A polyimide resin having a yellow index (YI) of 20 or less at a film thickness of 10 µm. A polyamic acid having a structural unit AA derived from tetracarboxylic dianhydride and a structural unit BA derived from diamine,
The structural unit AA includes a structural unit (AA1) derived from a compound represented by the following formula (a1),
A polyamic acid in which the structural unit BA contains a structural unit (BA1) derived from a compound represented by the following formula (b1).
[Formula 3]

(In the formula, R is each independently a methyl group or a trifluoromethyl group, and n is an integer of 1 to 4.) According to claim 7,
A polyimide acid in which the structural unit (AA1) derived from the compound represented by the formula (a1) is a structural unit (AA11) derived from the compound represented by the following formula (a11).
[Formula 4]

According to claim 7 or 8,
Polyimide acid whose ratio of structural unit (AA1) in structural unit AA is 50-100 mol%. According to any one of claims 7 to 9,
Polyimide acid whose ratio of the structural unit (BA1) in structural unit BA is 50-100 mol%. A varnish obtained by dissolving the polyamic acid according to any one of claims 7 to 10 in an organic solvent. According to claim 11,
A varnish further comprising a compound represented by the following formula (y1).
[Formula 5]

A polyimide film obtained by applying the varnish according to claim 11 or 12 on a support and heating it. A method for producing a polyimide film comprising applying the varnish according to claim 11 or 12 onto a support and heating the varnish. A polyimide film comprising the polyimide resin according to any one of claims 1 to 6.