TW202124531A - Polyimide resin, polyimide varnish, and polyimide film - Google Patents

Abstract

A polyimide resin having a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine, wherein the structural unit A includes a structural unit (A-1) derived from the compound represented by formula (a-1) shown below, and the structural unit B includes a structural unit (B-1) derived from the compound represented by formula (b-1) shown below and a structural unit (B-2) derived from the compound represented by formula (b-2) shown below.

Description

Polyimide resin, polyimide varnish and polyimide film

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

Some people have discussed the various applications of polyimide resins in the fields of electrical and electronic parts. For example, for the purpose of reducing the weight and flexibility of the device, it is expected to replace the glass substrate used in image display devices such as liquid crystal displays and OLED displays with plastic substrates. Research on polyimide films suitable as plastic substrates is underway. conduct. In an image display device, when the light emitted from the display element is emitted through the plastic substrate, the plastic substrate is required to be colorless and transparent. When the light passes through the retardation film or polarizing plate (such as liquid crystal display, touch panel, etc.) ), in addition to colorless transparency, high optical isotropy (that is, low Rth) is also required.

In order to meet such performance, the development of polyimide resins of various compositions is underway. For example, Patent Document 1 discloses a polyimide film for the purpose of obtaining a polyimide film that contains polyimide that has good solvent solubility and is excellent in processability, is colorless, transparent, and has excellent toughness, including 3, The structure composed of the combination of 3'-diaminodiphenyl sulfide and other specific diamines is used as the diamine component. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2016/158825

[The problem to be solved by the invention]

As mentioned above, good optical properties such as colorless transparency and optical isotropy are required for polyimide films. Especially for applications such as liquid crystal displays, optical isotropy is important. On the other hand, since polyimide has a rigid and strong molecular structure, breakage becomes a problem when manufacturing films or when using products with movable parts. If a component with high flexibility is introduced into the molecule in order to suppress breakage, or an additive is added to the resin, the optical properties generally decrease. In this way, a polyimide film with good optical properties and ductility is required. In addition, chemical resistance is also important. For example, when a varnish for forming the resin layer is applied to the polyimide film in order to form another resin layer (e.g., color filter, resist) on the polyimide film, the polyimide film The amine film requires resistance to the solvent contained in the varnish. If the solvent resistance of the polyimide film is insufficient, the film may lose its function as a substrate due to the dissolution and swelling of the film. However, as mentioned above, in order to ensure the optical properties, the polyimide film must be prepared in the form of a solution, and it is difficult to balance these properties. In this way, there is a need for a polyimide resin that can maintain the optical properties of the obtained polyimide film, especially the optical isotropy, and at the same time, obtain a polyimide film with flexibility and excellent chemical resistance. The subject of the present invention is to provide polyimide resins, polyimide varnishes, and polyimide films that can form films that are excellent in optical isotropy, and also excellent in flexibility and chemical resistance. [Means to solve the problem]

The inventors of the present invention found that a polyimide resin containing a combination of a structural unit derived from a specific tetracarboxylic dianhydride and a structural unit derived from two specific diamines can solve the above-mentioned problems, and completed the present invention.

That is, the present invention relates to the following <1> to <8>. <1> A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from a diamine, and the structural unit A includes a structural unit (A) derived from a compound represented by the following formula (a-1) -1), The structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1) and a structural unit (B-2) derived from a compound represented by the following formula (b-2).

[化1]

<2> The polyimide resin as in the above <1>, wherein the ratio of the structural unit (B-1) in the structural unit B is 5 to 80 mol%, and the structural unit (B-2) in the structural unit B The ratio of) is 20 to 95 mol%. <3> The polyimide resin such as <1> or <2>, wherein the molar ratio of the structural unit (B-1) and the structural unit (B-2) in the structural unit B [(B-1) /(B-2)] is 5/95～80/20. <4> The polyimide resin according to any one of the above <1> to <3>, wherein the structural unit A further includes a structural unit selected from the compound represented by the following formula (a-2-1) (A-2-1), and at least one of the group consisting of the structural unit (A-2-2) from the compound represented by the following formula (a-2-2).

[化2]

<5> The polyimide resin according to any one of the above <1> to <4>, wherein the structural unit B further includes a structural unit selected from the compound represented by the following formula (b-3-1) ( B-3-1), and at least one of the group consisting of the structural unit (B-3-2) from the compound represented by the following formula (b-3-2).

(式(b-3-1)中，Z¹ 及Z² 各自獨立地表示也可含有氧原子之2價脂肪族基、或2價芳香族基，R¹ 及R² 各自獨立地表示1價芳香族基或1價脂肪族基，R³ 及R⁴ 各自獨立地表示1價脂肪族基，R⁵ 及R⁶ 各自獨立地表示1價脂肪族基或1價芳香族基，m及n各自獨立地表示1以上之整數，m與n的和為2～1000之整數。惟，R¹ 及R² 之至少一者表示1價芳香族基。)[化3]

(In formula (b-3-1), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group that may also contain an oxygen atom, and R ¹ and R ² each independently represent a monovalent group An aromatic group or a monovalent aliphatic group, R ³ and R ⁴ each independently represent a monovalent aliphatic group, R ⁵ and R ⁶ each independently represent a monovalent aliphatic group or a monovalent aromatic group, m and n each independently It independently represents an integer of 1 or more, and the sum of m and n is an integer of 2 to 1000. However, ^{at least one of R 1} and R ² represents a monovalent aromatic group.)

<6> The polyimide resin according to the above <5>, wherein R ¹ and R ^{2 in} the formula (b-3-1) are phenyl groups. <7> A polyimide varnish obtained by dissolving the polyimide resin of any one of the above <1> to <6> in an organic solvent. <8> A polyimide film containing the polyimide resin of any one of the above <1> to <6>. [Effects of Invention]

According to the present invention, it is possible to provide a polyimide resin, a polyimide varnish, and a polyimide film that can form a film having excellent optical isotropy, flexibility and chemical resistance.

[Polyimide resin] The polyimide resin of the present invention has a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from a diamine, and the structural unit A includes a structural unit (A-1) derived from a compound represented by the following formula (a-1) ), the structural unit B includes the structural unit (B-1) derived from the compound represented by the following formula (b-1) and the structural unit (B-2) derived from the compound represented by the following formula (b-2).

[化4]

In addition, the reason why the polyimide resin of the present invention can maintain optical isotropy while being excellent in flexibility and chemical resistance is not certain. It is believed that the polyimide resin of the present invention has an alicyclic structure at an appropriate ratio. , Ether skeleton and aromatic, so it can maintain optical isotropy while being excellent in flexibility and chemical resistance. Among them, since the structure contains a structural unit derived from a small diamine having an alicyclic structure, the concentration of the imine group increases, the optical isotropy can be maintained, and the chemical resistance is very excellent.

＜Construction Unit A＞ The structural unit A is a structural unit derived from tetracarboxylic dianhydride which is occupied in the polyimide resin. The structural unit A includes the structural unit (A-1) derived from the compound represented by the following formula (a-1).

[化5]

The compound represented by the formula (a-1) is 4,4'-oxydiphthalic anhydride. Since the constituent unit A includes the constituent unit (A-1), the chemical resistance and toughness of the film can be improved.

The ratio of the constituent unit (A-1) in the constituent unit A is preferably 40 mol% or more, more preferably 50 mol% or more, more preferably 55 mol% or more, and more preferably 60 mol% above. Considering the toughness of the film, it is more preferably 70 mol% or more. The upper limit of the ratio of the constituent unit (A-1) is not particularly limited, that is, it is 100 mol%. The structural unit A may consist of only the structural unit (A-1).

The structural unit A may include structural units other than the structural unit (A-1). From the viewpoint of heat resistance, in addition to the structural unit (A-1), the structural unit A preferably further contains a structural unit (A-2-1) selected from the compound represented by the following formula (a-2-1) , And a structural unit (A-2) derived from at least one of the group consisting of the structural unit (A-2-2) of the compound represented by the following formula (a-2-2). That is, the structural unit (A-2-1) and the structural unit (A-2-2) are collectively referred to as the structural unit (A-2).

[化6]

The compound represented by the formula (a-2-1) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride. The compound represented by the formula (a-2-2) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6'' -Tetracarboxylic dianhydride. Considering the viewpoint of improving heat resistance, chemical resistance and optical isotropy, the ratio of the constituent unit (A-2) in constituent unit A is preferably 10-50 mol%, more preferably 15-45 mol%, It is more preferably 20-40 mol%. When the structural unit A includes the structural unit (A-2), considering the viewpoint of improving heat resistance, chemical resistance, and optical isotropy, the structural unit (A-1) and the structural unit (A-2) in the structural unit A The molar ratio [(A-1)/(A-2)] is preferably 50/50 to 90/10, more preferably 55/45 to 85/15, and even more preferably 60/40 to 80/20.

The structural unit A may include structural units other than the structural unit (A-1) and the structural unit (A-2). The tetracarboxylic dianhydride providing such a structural unit is not particularly limited, and examples include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 9,9 '-Bis(3,4-dicarboxyphenyl) dianhydride, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride and other aromatic tetracarboxylic dianhydrides (exclusive formula (a-1) the compound represented); alicyclic tetracarboxylic dianhydride such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride (except formula (a-2-1) and formula (a -2-2) The compound represented by); and aliphatic tetracarboxylic dianhydride such as 1,2,3,4-butanetetracarboxylic dianhydride. In addition, in this specification, aromatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing more than one aromatic ring, and alicyclic tetracarboxylic dianhydride refers to containing more than one alicyclic ring and does not contain aromatic Cyclic tetracarboxylic dianhydride and aliphatic tetracarboxylic dianhydride refer to tetracarboxylic dianhydride that does not contain aromatic or alicyclic rings. The structural unit arbitrarily included in the structural unit A may be one type or two or more types.

＜Construction unit B＞ The structural unit B is a structural unit derived from a diamine in the polyimide resin, and includes a structural unit (B-1) derived from the compound represented by the following formula (b-1) and derived from the following formula (b-2) The structural unit (B-2) of the indicated compound.

式(b-1)表示之化合物係4,4’-二胺基-2,2’-雙三氟甲基二苯基醚。 藉由構成單元B包含構成單元(B-1)，可改善薄膜的光學等向性及無色透明性。[化7]

The compound represented by the formula (b-1) is 4,4'-diamino-2,2'-bistrifluoromethyl diphenyl ether. Since the constituent unit B includes the constituent unit (B-1), the optical isotropy and colorless transparency of the film can be improved.

The compound represented by the formula (b-2) is bis(aminomethyl)cyclohexane, and specific examples thereof include 1,3-bis(aminomethyl) represented by the following formula (b-2a) Cyclohexane, 1,4-bis(aminomethyl)cyclohexane represented by the following formula (b-2b).

考量耐有機溶劑性、耐熱性之觀點，式(b-2)表示之化合物之順：反比宜為0：100～80：20，更宜為0.1：99.9～70：30，又更宜為0.5：99.5～60：40，又更宜為1：99～20：80。 藉由構成單元B包含構成單元(B-2)，可改善薄膜之光學等向性、柔軟性及耐藥品性。[化8]

Considering the organic solvent resistance and heat resistance, the cis:inverse ratio of the compound represented by formula (b-2) is preferably 0:100～80:20, more preferably 0.1:99.9～70:30, and even more preferably 0.5 ：99.5～60:40, and more preferably 1:99～20:80. Since the constituent unit B includes the constituent unit (B-2), the optical isotropy, flexibility, and chemical resistance of the film can be improved.

The ratio of the constituent unit (B-1) in the constituent unit B is preferably 5 to 80 mol%, more preferably 10 to 70 mol%, and more preferably 30 to 60 mol%. The ratio of the constituent unit (B-2) in the constituent unit B is preferably 20 to 95 mol%, more preferably 30 to 90 mol%, and even more preferably 40 to 70 mol%. The total ratio of the constituent units (B-1) and (B-2) in the constituent unit B is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. The upper limit of the total ratio of the constituent units (B-1) and (B-2) is not particularly limited, that is, 100 mol%. The structural unit B may consist of only the structural unit (B-1) and the structural unit (B-2). Considering the viewpoint of improving the optical isotropy and chemical resistance, the molar ratio of the structural unit (B-1) and the structural unit (B-2) in the structural unit B [(B-1)/(B-2)] It is preferably 5/95～80/20, more preferably 10/90～70/30, and even more preferably 30/70～60/40

The structural unit B may include structural units other than the structural units (B-1) and (B-2). In addition to the structural units (B-1) and (B-2), the structural unit B preferably further contains a structural unit (B-3-1) selected from the compound represented by the following formula (b-3-1) , A structural unit (B-3) derived from at least one of the group consisting of the structural unit (B-3-2) of the compound represented by the following formula (b-3-2). That is, the structural unit (B-3-1) and the structural unit (B-3-2) are collectively referred to as the structural unit (B-3). Among them, the structural unit B preferably further includes the structural unit (B-3-1) derived from the compound represented by the following formula (b-3-1).

[化9]

In formula (b-3-1), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group that may also contain an oxygen atom, and R ¹ and R ² each independently represent a monovalent aromatic group A group or a monovalent aliphatic group, R ³ and R ⁴ each independently represent a monovalent aliphatic group, R ⁵ and R ⁶ each independently represent a monovalent aliphatic group or a monovalent aromatic group, m and n are each independently Ground represents an integer of 1 or more, and the sum of m and n is an integer of 2 to 1000. However, ^{at least one of R 1} and R ² represents a monovalent aromatic group. In addition, in formula (b-3-1), the two or more distinct repeating units described in [], regardless of the order of [], can be in any of random, alternating or block forms. And repeat in order.

In the formula (b-3-1), the divalent aliphatic group or the divalent aromatic group ^{in Z 1} and Z ^{2 may be substituted with a fluorine atom.} The divalent aliphatic group includes a divalent saturated or unsaturated aliphatic group having 1 to 20 carbon atoms, and an aliphatic group containing an oxygen atom. The carbon number of the divalent aliphatic group is preferably 3-20. As for the divalent saturated aliphatic group, alkylene groups having 1 to 20 carbon atoms, such as methylene, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, octa Methylene, decamethylene, dodecamethylene, etc. The divalent unsaturated aliphatic group includes an alkenylene group having 2 to 20 carbon atoms, such as an ethylene group, an propylene group, and an alkylene group having an unsaturated double bond at the end. The aliphatic group containing an oxygen atom includes an alkoxy group and an aliphatic group having an ether bond. As the alkoxyl group, propyleneoxy group and trimethyleneoxy group can be exemplified. Examples of the divalent aromatic group include an arylene group having 6 to 20 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, and the like. Specific examples of the arylene groups having 6 to 20 carbon atoms in Z ¹ and Z ² include: o-phenylene, meta-phenylene, p-phenylene, 4,4'-biphenylene , 2,6-naphthylene and so on. As for Z ¹ and Z ² , the trimethylene group and the p-phenylene group are particularly preferable, and the trimethylene group is more preferable.

In the formula (b-3-1), ^{the monovalent aliphatic group among R 1} to R ⁶ includes a monovalent saturated or unsaturated aliphatic group. Examples of monovalent saturated aliphatic groups include alkyl groups having 1 to 22 carbon atoms, and examples include methyl, ethyl, and propyl groups. Examples of the monovalent unsaturated aliphatic group include alkenyl groups having 2 to 22 carbon atoms, such as vinyl groups and propenyl groups. These groups may also be substituted by fluorine atoms. ^{Regarding the monovalent aromatic group in R 1} , R ² , R ⁵ and R ⁶ of the formula (b-3-1), examples include: an aryl group with 6 to 20 carbons, an aryl group with 7 to 30 carbons, and An aryl group substituted by an alkyl group, an aralkyl group having 7 to 30 carbon atoms, etc. As for the monovalent aromatic group, an aryl group is preferable, and a phenyl group is more preferable. At least one of R ¹ and R ² represents a monovalent aromatic group, preferably R ¹ and R ² are both monovalent aromatic groups, and more preferably R ¹ and R ² are both phenyl groups. R ³ and R ⁴ are preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group. R ⁵ and R ⁶ are preferably a monovalent aliphatic group, more preferably a methyl group.

As above, among the compounds represented by the formula (b-3-1), the compound represented by the following formula (b-3-11) is preferred.

(式(b-3-11)中，m及n分別與式(b-3-1)之m及n為同義，理想的範圍亦相同。)[化10]

(In formula (b-3-11), m and n have the same meaning as m and n in formula (b-3-1), and the ideal range is also the same.)

The m in formula (b-3-1) and formula (b-3-11) represents the repeating number of siloxane units bonded with at least one monovalent aromatic group, formula (b-3- 1) and in formula (b-3-11), n represents the repeating number of the siloxane unit to which the monovalent aliphatic group is bonded. In formula (b-3-1) and formula (b-3-11), m and n each independently represent an integer of 1 or more, and the sum of m and n (m+n) represents an integer of 2 to 1000. The sum of m and n is preferably an integer of 3 to 500, more preferably 3 to 100, and even more preferably an integer of 3 to 50. The ratio of m/n in formula (b-3-1) and formula (b-3-11) is preferably 5/95～50/50, more preferably 10/90～40/60, and even more preferably 20 /80～30/70.

The functional group equivalent (amine equivalent) of the compound represented by the formula (b-3-1) is preferably 150-5,000 g/mol, more preferably 400-4,000 g/mol, and even more preferably 500-3,000 g/mol. In addition, the functional group equivalent refers to the mass of the compound represented by the formula (b-3-1) per 1 mole of the functional group (amine group).

Among the compounds represented by the formula (b-3-1), those that can be obtained as commercially available products include "X-22-9409" and "X-22-1660B manufactured by Shin-Etsu Chemical Co., Ltd. ", "X-22-161A", "X-22-161B", etc.

Since the constituent unit B includes the constituent unit (B-3-1), the colorless transparency, optical isotropy, and flexibility of the film can be improved.

The formula (b-3-2) is 4,4'-diaminodiphenyl sulfide. Since the constituent unit B includes the constituent unit (B-3-2), the colorless transparency, toughness, and chemical resistance of the film can be improved.

When the structural unit B includes the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3), the structural unit (B-1) and the structural unit (B-2) in the structural unit B The total ratio should be 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more, and the ratio of the constituent unit (B-3) in the constituent unit B should be 0.1-30 mol% %, more preferably 1-25 mol%, more preferably 2-20 mol%, and still more preferably 3-15 mol%. The total ratio of constituent unit (B-1), constituent unit (B-2) and constituent unit (B-3) in constituent unit B should be 80 mol% or more, more preferably 90 mol% or more, especially It is more than 99 mol%. The upper limit of the total ratio of the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3) is not particularly limited, and is 100 mol%. The structural unit B may be composed of only the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3).

When structural unit B includes structural unit (B-1), structural unit (B-2), and structural unit (B-3-1), structural unit (B-1) and structural unit (B-2) in structural unit B The total ratio of) should be 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more, and the ratio of the constituent unit (B-3-1) in the constituent unit B should be 0.1 ～30 mol%, more preferably 1-25 mol%, still more preferably 2-20 mol%, still more preferably 3-15 mol%, and still more preferably 3-10 mol%. The total ratio of the structural unit (B-1), the structural unit (B-2) and the structural unit (B-3-1) in the structural unit B should be 80 mol% or more, more preferably 90 mol% or more, Particularly, it is more than 99 mol%. The upper limit of the total ratio of the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3-1) is not particularly limited, that is, 100 mol%. The structural unit B may be composed of only the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3-1).

When structural unit B includes structural unit (B-1), structural unit (B-2), and structural unit (B-3-2), structural unit (B-1) and structural unit (B-2) in structural unit B The total ratio of) should be 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more, considering the colorless transparency, toughness, and chemical resistance of the film, the constituent unit B The ratio of the constituent unit (B-3-2) is preferably 2-30 mol%, more preferably 3-30 mol%, more preferably 10-30 mol%, and more preferably 15-30 mol% Ear%, and more preferably 15-25 mole%. The total ratio of the structural unit (B-1), the structural unit (B-2) and the structural unit (B-3-2) in the structural unit B is preferably 80 mol% or more, more preferably 90 mol% or more, Particularly, it is more than 99 mol%. The upper limit of the total ratio of the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3-2) is not particularly limited, that is, 100 mol%. The structural unit B may be composed of only the structural unit (B-1), the structural unit (B-2), and the structural unit (B-3-2).

The structural unit (B-3) may be only the structural unit (B-3-1), or only the structural unit (B-3-2), or may be the structural unit (B-3-1) and the structural unit ( The combination of B-3-2).

The structural unit B may also include structural units other than the structural units (B-1), (B-2), and (B-3). There are no particular limitations on the diamine providing the constituent units in this way, and examples include 1,4-phenylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, and 2,2'- Dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2-bis(4-amino) Phenyl) hexafluoropropane, 4,4'-diaminobenzaniline, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H- Indene-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)p-xylylenedimethamide , 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-( Aromatic diamines such as 4-aminophenoxy)phenyl)hexafluoropropane, and 9,9-bis(4-aminophenyl)stilbene (except for compounds represented by formula (b-1), formula (b-3-1) the compound represented by the formula (b-3-2)); alicyclic diamine (except the compound represented by the formula (b-2)); and ethylene diamine and hexa Aliphatic diamines such as methylene diamine. In addition, in this specification, aromatic diamine refers to diamine containing more than one aromatic ring, alicyclic diamine refers to diamine containing more than one alicyclic ring and no aromatic ring, aliphatic diamine Refers to diamines that do not contain aromatic or alicyclic rings. The structural units other than the structural units (B-1), (B-2), and (B-3) optionally included in the structural unit B may be one type or two or more types.

＜Characteristics of polyimide resin＞ Considering the mechanical strength of the obtained polyimide film, the number average molecular weight of the polyimide resin is preferably 5,000-300,000. In addition, the number average molecular weight of the polyimide resin can be obtained by, for example, a standard polymethyl methacrylate (PMMA) conversion value obtained by gel filtration chromatography measurement.

The polyimide resin may also include a structure other than the polyimine chain (a structure in which the structural unit A and the structural unit B are bonded via an imine). Regarding the structure other than the polyimide chain that can be contained in the polyimide resin, for example, a structure containing an amide bond or the like can be mentioned. The polyimide resin preferably contains a polyimine chain (a structure in which the constituent unit A and the constituent unit B are bonded via an imine) as a main structure. Therefore, the ratio of the polyimide chains in the polyimide resin is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 99% by mass or more.

The polyimide resin composition of the present invention containing the above-mentioned polyimide resin can form a film with excellent colorless transparency, optical isotropy, and chemical resistance. The ideal physical properties of the film are as follows .

When the total light transmittance is made into a film with a thickness of 10μm, it is preferably 88% or more, more preferably 88.5% or more, and even more preferably 89% or more. When the yellow index (YI) is made into a film with a thickness of 10 μm, it is preferably 4.5 or less, more preferably 3.0 or less, more preferably 2.0 or less, and more preferably 1.5 or less. The absolute value of the thickness retardation (Rth) is preferably 70 nm or less, more preferably 60 nm or less, and even more preferably 50 nm or less when a film with a thickness of 10 μm is formed.

In addition, a film that can be formed using the above-mentioned polyimide resin has good mechanical properties and heat resistance, and has the following ideal physical property values. The film formed by using the polyimide resin of the present invention has good mechanical properties and heat resistance, and has the following ideal physical properties. The tensile strength is preferably 70 MPa or more, more preferably 80 MPa or more, and even more preferably 90 MPa or more. The coefficient of tensile elasticity is preferably 2.0 GPa or more, more preferably 2.5 GPa or more, and even more preferably 3.0 GPa or more. The elongation at break is preferably 8% or more, more preferably 10% or more, and even more preferably 15% or more. The glass transition temperature (Tg) is preferably 200°C or higher, more preferably 230°C or higher, and even more preferably 250°C or higher. In addition, the above-mentioned physical property values in the present invention can be specifically measured by the methods described in the examples.

<Method for manufacturing polyimide resin> In the present invention, the polyimide resin can be prepared by combining a tetracarboxylic acid component containing a compound providing the above-mentioned structural unit (A-1) with a compound providing the above-mentioned structural unit (B-1) and providing the above-mentioned structural unit ( It is produced by reacting the diamine component of the compound of B-2).

As for the compound providing the structural unit (A-1), the compound represented by the formula (a-1) can be cited, but it is not limited to these, and its derivative may be provided within the range that the same structural unit can be provided. As for the derivative, the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-1) (that is, 4,4'-oxydiphthalic acid), and the alkane of the tetracarboxylic acid ester. Among them, tetracarboxylic dianhydride represented by formula (a-1) is preferable.

The tetracarboxylic acid component preferably contains 40 mol% or more of the compound providing the constituent unit (A-1), more preferably 50 mol% or more, and more preferably 70 mol% or more. The upper limit of the content of the compound providing the constituent unit (A-1) is not particularly limited, that is, 100 mol%. The tetracarboxylic acid component may be composed only of the compound providing the structural unit (A-1).

The tetracarboxylic acid component may also contain compounds other than the compound providing the constituent unit (A-1).

The tetracarboxylic acid component may contain a compound that provides the structural unit (A-2) in addition to the compound that provides the structural unit (A-1). As for the compound providing the constituent unit (A-2), the compound represented by the formula (a-2-1) and the compound represented by the formula (a-2-2) can be cited, but it is not limited to these, and the same can be provided. The range of the constituent unit may also be a derivative thereof. The derivatives include tetracarboxylic acids corresponding to the compounds represented by formulas (a-2-1) and (a-2-2) and alkyl esters of the tetracarboxylic acids. As far as the compound providing the constituent unit (A-2) is concerned, the compound represented by the formula (a-2-1) and the formula (a-2-2) (that is, the dianhydride) is preferable.

When the tetracarboxylic acid component contains a compound that provides the constituent unit (A-2), the tetracarboxylic acid component preferably contains 10-50 mol% of the compound that provides the constituent unit (A-2), more preferably 15-45 mol% , And more preferably 20-40 mol%.

The compound arbitrarily contained in the tetracarboxylic acid component other than the compound providing the structural unit (A-1) is not limited to the compound providing the structural unit (A-2). For such arbitrary compounds, the above-mentioned aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides, and their derivatives (tetracarboxylic, tetracarboxylic dianhydrides, Alkyl esters of carboxylic acids, etc.). The compound other than the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2) optionally contained in the tetracarboxylic acid component may be one type or two or more types.

As for the compound providing the structural unit (B-1), the compound represented by the formula (b-1) can be cited, but it is not limited to these, and its derivative may be provided within the range that the same structural unit can be provided. The derivatives include diisocyanates corresponding to the compounds (diamines) represented by formula (b-1). Among them, it is preferably a compound represented by formula (b-1) (that is, diamine). Similarly, with regard to the compound providing the structural unit (B-2), the compound represented by the formula (b-2) can be cited, but it is not limited to these, and its derivatives may also be provided within the range of providing the same structural unit . The derivatives include diisocyanates corresponding to the compounds (diamines) represented by formula (b-2). As far as the compound providing the constituent unit (B-2) is concerned, it is preferably a compound represented by the formula (b-2) (that is, a diamine).

The diamine component preferably contains 5 to 80 mol% of the compound providing the constituent unit (B-1), more preferably 10 to 70 mol%, and more preferably 30 to 60 mol%. The diamine component preferably contains 20 to 95 mole% of the compound providing the constituent unit (B-2), more preferably 30 to 90 mole%, and more preferably 40 to 70 mole%. The diamine component should preferably contain 50 mol% or more, more preferably 70 mol% or more, and more preferably the total of the compound providing the constituent unit (B-1) and the compound providing the constituent unit (B-2) Contains more than 90 mol%. The upper limit of the total content of the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2) is not particularly limited, that is, 100 mol%. The diamine component may consist only of the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2).

The diamine component may contain compounds other than the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2).

In addition to the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2), the diamine component may further contain a compound providing the structural unit (B-3). As for the compound providing the constituent unit (B-3), the compound represented by the formula (b-3-1) and the compound represented by the formula (b-3-2) can be cited, but it is not limited to these, and the same The range of the constituent unit may also be a derivative thereof. The derivatives include diisocyanates corresponding to the diamine represented by the formula (b-3-1) and diisocyanates corresponding to the diamine represented by the formula (b-3-2). As for the compound providing the constituent unit (B-3), the compound represented by the formula (b-3-1) and the compound represented by the formula (b-3-2) (that is, diamine) are preferable.

As far as the compound providing the constituent unit (B-3) is concerned, it may be only the compound represented by the formula (b-3-1), or only the compound represented by the formula (b-3-2), or may be of the formula ( Combination of the compound represented by b-3-1) and the compound represented by formula (b-3-2).

When the diamine component contains a compound that provides the constituent unit (B-3), the diamine component preferably contains 0.1-30 mol% of the compound that provides the constituent unit (B-3), and more preferably contains 1-25 mol% , And more preferably contains 5-25 mol%. When the diamine component contains a compound that provides the structural unit (B-3), in the diamine component, the compound that provides the structural unit (B-1), the compound that provides the structural unit (B-2), and the compound that provides the structural unit (B- 3) The total content of the compounds is preferably 80 mol% or more, more preferably 90 mol% or more, and more preferably 99 mol% or more. The upper limit of the total content of the compound providing structural unit (B-1), the compound providing structural unit (B-2), and the compound providing structural unit (B-3) is not particularly limited, that is, 100 mol %. The diamine component may be composed only of the compound providing the structural unit (B-1), the compound providing the structural unit (B-2), and the compound providing the structural unit (B-3).

Compounds other than the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2) optionally contained in the diamine component are not limited to the compound providing the structural unit (B-3). Such arbitrary compounds include the above-mentioned aromatic diamines, alicyclic diamines, and aliphatic diamines, and derivatives of these (diisocyanates, etc.). The compound other than the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2) optionally contained in the diamine component may be one type or two or more types.

In the present invention, the feed 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 mol of the diamine component relative to 1 mol of the tetracarboxylic acid component.

In addition, in the production of the polyimide resin in the present invention, in addition to the aforementioned tetracarboxylic acid component and diamine component, an end-capping agent may also be used. The blocking agent is preferably monoamine or dicarboxylic acid. Regarding the feed amount of the capping agent to be introduced, it is preferably 0.0001 to 0.1 mol, and more preferably 0.001 to 0.06 mol relative to 1 mol of the tetracarboxylic acid component. For monoamine blocking agents, for example: methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine , 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc., preferably benzylamine, aniline. The dicarboxylic acid type blocking agent is preferably a dicarboxylic acid type, and a part of the ring may be closed. Examples include: phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone two Formic acid, cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc., preferably phthalic acid, phthalic anhydride .

The method of reacting the said tetracarboxylic acid component and a diamine component is not specifically limited, A well-known method can be used. Specific reaction methods include: (1) The tetracarboxylic acid component, the diamine component, and the reaction solvent are fed to the reactor, stirred at 0 to 80°C for 0.5 to 30 hours, and thereafter heated and carried out. The method of imidization reaction, (2) After the diamine component and the reaction solvent are fed into the reactor and dissolved, the tetracarboxylic acid component is added, and the mixture is stirred at 0～80℃ for 0.5～30 hours, and then the temperature is raised. And the method of carrying out the imidization reaction, (3) the method of feeding the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, immediately raising the temperature and carrying out the imidization reaction, etc.

The reaction solvent used in the production of the polyimide resin may be one that does not hinder the imidization reaction and can dissolve the polyimide produced. For example, aprotic solvents, phenolic solvents, ether solvents, carbonate solvents, etc. may be mentioned.

Specific examples of aprotic solvents include: N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), Amine-based solvents such as N-methylcaprolactone, 1,3-dimethylimidazolidinone, and tetramethylurea; lactone-based solvents such as γ-butyrolactone (GBL) and γ-valerolactone; Phosphorus-containing amine-based solvents such as hexamethylphosphamide and hexamethylphosphine triamide; sulfur-containing solvents such as dimethyl sulfonium, dimethyl sulfide, and cyclobutane; Ketone solvents such as cyclohexanone; amine solvents such as picoline and pyridine; ester solvents such as acetic acid (2-methoxy-1-methylethyl).

Specific examples of phenolic solvents 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. Specific examples of ether solvents include: 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy) ) Ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, etc. In addition, specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate. Among the above-mentioned reaction solvents, aprotic solvents are preferred, and amide solvents and lactone solvents are more preferred. Moreover, the said reaction solvent may be used individually or in mixture of 2 or more types.

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

In the above-mentioned imidization reaction, a well-known imidization catalyst can be used. As for the imidization catalyst, an alkali catalyst or an acid catalyst can be mentioned. As for the alkali catalyst, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, Organic base catalysts such as triethylamine (TEA), tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline, etc.; potassium hydroxide or hydroxide Sodium, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate and other inorganic base catalysts. In addition, as the acid catalyst, crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, P-toluenesulfonic acid, naphthalenesulfonic acid, etc. The said imidization catalyst may be used individually or in combination of 2 or more types. From the viewpoint of operability, among the above, it is better to use an alkali catalyst, more preferably to use an organic alkali catalyst, and more preferably to use triethylamine.

Considering the viewpoints of inhibiting reaction rate and gelation, the temperature of the imidization reaction is preferably 120-250°C, more preferably 160-200°C. In addition, the reaction time is preferably 0.5 to 10 hours after the start of the distillation of the produced water.

[Polyimide varnish] The polyimide varnish of the present invention is formed by dissolving the polyimide resin of the present invention in an organic solvent. That is, the polyimide varnish of the present invention contains the polyimide resin of the present invention and an organic solvent, and the polyimide resin is dissolved in the organic solvent. The organic solvent is not particularly limited as long as it can dissolve the polyimide resin, and the above-mentioned compound is preferably used as a reaction solvent used in the production of the polyimide resin, singly or as a mixture of two or more. The polyimide varnish of the present invention can be the polyimide solution itself obtained by dissolving the polyimide resin obtained by the polymerization method in the reaction solvent, or it can also be the polyimide solution that is further added with a solvent and diluted Become.

The polyimide resin of the present invention has solvent solubility, so it can be made into a high-concentration varnish that is stable at room temperature. The polyimide varnish of the present invention preferably contains 5-40% by mass of the polyimide resin of the present invention, and more preferably contains 10-30% by mass. The viscosity of the polyimide varnish is preferably 1～200Pa･s, more preferably 1～100Pa･s. The viscosity of the polyimide varnish is measured at 25°C with an E-type viscometer. In addition, the polyimide varnish of the present invention may also contain inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, and interface materials within the range that does not impair the required characteristics of the polyimide film. Various additives such as active agent, leveling agent, defoaming agent, fluorescent whitening agent, cross-linking agent, polymerization initiator, sensitizer, etc. The manufacturing method of the polyimide varnish of this invention is not specifically limited, A well-known method can be used.

[Polyimide film] The polyimide film of the present invention contains the polyimide resin of the present invention. Therefore, the polyimide film of the present invention is excellent in optical isotropy, flexibility, and chemical resistance. The ideal physical properties of the polyimide film of the present invention are as described above. The manufacturing method of the polyimide film of this invention is not specifically limited, 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, a metal plate, or plastic, or formed into a film, and then heated to remove the reaction solvent and diluting solvent contained in the varnish And other organic solvent methods.

The coating method includes well-known coating methods such as spin coating, slit coating, and knife coating. Among them, considering the viewpoint of controlling the intermolecular alignment and improving chemical resistance and workability, slit coating is preferable. As far as the method of removing the organic solvent contained in the varnish by heating is concerned, it is preferable to evaporate the organic solvent at a temperature below 150°C and become non-viscous, and then at a temperature above the boiling point of the organic solvent (not particularly limited, preferably 200～500℃) for drying. Moreover, it is suitable to dry in an air environment or a nitrogen environment. The pressure of the dry environment can be any one of reduced pressure, normal pressure, and increased pressure. The method of peeling the polyimide film formed on the support from the support is not particularly limited. Examples include the laser peeling method and the method of using a sacrificial layer for peeling (pre-coating a release agent on the surface of the support). Method), the method of adding a stripping agent.

In addition, the polyimide film of the present invention can also be produced using a polyimide varnish obtained by dissolving polyimide acid in an organic solvent. The polyimide contained in the aforementioned polyimide varnish is the precursor of the polyimide resin of the present invention, is the tetracarboxylic acid component containing the compound of the above-mentioned providing structural unit (A-1), and contains the above-mentioned providing The product of the addition polymerization reaction of the compound of the constituent unit (B-1) and the diamine component that provides the compound of the constituent unit (B-2). The polyimide resin of the present invention can be obtained as the final product by carrying out imidization (dehydration and ring closure) of the polyimide acid. As for the organic solvent contained in the aforementioned polyimide varnish, the organic solvent contained in the polyimide varnish of the present invention can be used. In the present invention, the polyamide varnish may be the polyamide solution itself obtained by the addition polymerization reaction of the tetracarboxylic acid component and the diamine component in the reaction solvent, or the polyamide acid solution may be further It is made by adding solvent and diluting.

The method of manufacturing a polyimide film using a polyamide varnish is not particularly limited, and a known method can be used. For example, a polyamide varnish can be coated on a smooth support such as a glass plate, a metal plate, or a plastic or formed into a thin film, and the organic solvents such as the reaction solvent and the dilution solvent contained in the varnish can be removed by heating to obtain the polyamide The polyamide film is then heated by heating the polyamide acid in the polyamide acid film to be imidized to produce the polyimide film. The heating temperature when drying the polyamic acid varnish to obtain the polyamic acid film is preferably 50 to 120°C. Regarding the heating temperature when the polyamide acid is imidized by heating, it is preferably 200 to 400°C. In addition, the method of imidization is not limited to thermal imidization, and chemical imidization may be used.

The thickness of the polyimide film of the present invention can be appropriately selected according to the application, etc., and is preferably 1 to 250 μm, more preferably 5 to 100 μm, more preferably 8 to 80 μm, and more preferably 10 to 80 μm. With a thickness of 1 to 250 μm, it can be used practically as a self-supporting film. The thickness of the polyimide film can be easily controlled by adjusting the solid content and viscosity of the polyimide varnish.

The polyimide film of the present invention can be ideally used as a film for various components such as color filters, flexible displays, semiconductor parts, and optical components. The polyimide film of the present invention is particularly suitable for use as a substrate for image display devices such as liquid crystal displays and OLED displays. [Example]

Hereinafter, the present invention will be specifically explained using examples. However, the present invention is not limited in any way by these embodiments.

＜Film properties and evaluation＞ The physical properties of the films obtained in the examples and comparative examples were measured by the methods shown below.

(1) Film thickness The film thickness is measured using a micrometer manufactured by Mitutoyo Corporation.

(2) Tensile strength, tensile modulus of elasticity, and tensile elongation at break (evaluation of flexibility at tensile elongation at break) The tensile strength, tensile modulus of elasticity and tensile elongation at break are measured in accordance with JIS K7127: 1999, using a tensile testing machine "STROGRAPH VG-1E" manufactured by Toyo Seiki Co., Ltd. The distance between the clamps was 50 mm, the size of the test piece was 10 mm×70 mm, and the test speed was 20 mm/min.

(3) Glass transition temperature (Tg) Using the thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., in the tensile mode, the sample size is 2mm×20mm, the load is 0.1N, and the heating rate is 10°C/min. The temperature is increased enough to remove The temperature of the residual stress is sufficient to remove the residual stress, and then it is cooled to room temperature. After that, under the same conditions as the aforementioned treatment for removing residual stress, the elongation of the test piece was measured, and the glass transition temperature was determined when the inflection point of the elongation was observed.

(4) Total light transmittance, and yellow index (YI) The total light transmittance and YI are measured in accordance with JIS K7136, using the color-turbidity simultaneous tester "COH7700" manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Haze The measurement was performed in accordance with JIS K7361-1, using the color-turbidity simultaneous measuring device "COH7700" manufactured by Nippon Denshoku Industries Co., Ltd.

(6) Thickness retardation (Rth) (evaluation of optical isotropy) The thickness phase difference (Rth) was measured using an ellipsometer "M-220" manufactured by JASCO Corporation. The value of the thickness retardation at the measurement wavelength of 590 nm is measured. In addition, Rth is to make the largest in-plane refractive index of the polyimide film be nx, the smallest one is ny, the refractive index in the thickness direction is nz, and the thickness of the film is d, which is expressed by the following formula . The Rth obtained by converting the thickness of the film to 10μm is also calculated. Rth={[(nx+ny)/2]-nz}×d

(7) Solvent resistance (evaluation of chemical resistance) The polyimide film formed by forming a film on a glass plate is immersed in a solvent at room temperature to confirm whether there is any change on the surface of the film. In addition, propylene glycol monomethyl ether acetate (PGMEA) was used as a solvent. The evaluation criteria of solvent resistance are as follows. ○: There is no change in the surface of the film. △: There are some microcracks on the surface of the film. ×: Cracks occurred on the film surface, or the film surface was dissolved.

＜Abbreviation of ingredients, etc.＞ The tetracarboxylic acid component and diamine component used in Examples and Comparative Examples, and their abbreviations are as follows.

(Tetracarboxylic acid component) ODPA: 4,4'-oxydiphthalic anhydride (manufactured by MANAC Co., Ltd.; compound represented by formula (a-1)) HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.; compound represented by formula (a-2-1)) CpODA: Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride (manufactured by JXTG Energy Co., Ltd.) ；The compound represented by the formula (a-2-2)) 6FDA: 4,4’-(hexafluoroisopropylene) diphthalic anhydride

(Diamine component) 6FODA: 4,4'-diamino-2,2'-bistrifluoromethyl diphenyl ether (manufactured by ChinaTech Chemical (Tianjin) Co., Ltd.; compound represented by formula (b-1)) 1,3-BAC: 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd.; compound represented by formula (b-2a)) 1,4-BAC: 1,4-bis(aminomethyl)cyclohexane (compound represented by formula (b-2b); cis ratio 40%) 1,4-BACT: 1,4-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd.; compound represented by formula (b-2b); cis rate 85%) X-22-9409: (manufactured by Shin-Etsu Chemical Co., Ltd.; compound represented by formula (b-3-1)) 4,4'-DDS: 4,4'-diaminodiphenyl sulfide (manufactured by SEIKA Co., Ltd.; compound represented by formula (b-3-2)) 3,3'-DDS: 3,3'-diaminodiphenyl sulfide (manufactured by SEIKA Co., Ltd.) TFMB: 2,2'-bis(trifluoromethyl)benzidine (manufactured by SEIKA Co., Ltd.)

<Production of polyimide resin, varnish and polyimide film> Example 1 Add 16.812 g (0.0500 mol) of 6FODA, 7.113 g (0.0500 mol) of 1,4-BACT and 65.935 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) Introductory tube, Dean-Stark device equipped with cooling tube, thermometer, and glass end cap in a 300mL 5-neck round-bottomed round bottom flask. Stir at 200 rpm at a system internal temperature of 70°C under nitrogen. And get the solution. 31.021 g (0.100 mol) of ODPA and 16.484 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) were added to the solution at a time, and 0.506 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an alcohol. The imidization catalyst is heated by a heating mantle, and the temperature in the reaction system rises to 190°C in about 20 minutes. Collect the distilled components, adjust the rotation speed according to the increase in viscosity, and keep the temperature in the reaction system at 190°C and reflux for about 5 hours. Then, 208.517 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added so that the solid content concentration was 15% by mass, and the temperature in the reaction system was cooled to 100° C., and then further stirred for about 1 hour. It is homogenized and a polyimide varnish is obtained. Then, the obtained polyimide varnish was coated on a glass plate by spin coating, and kept at 80°C for 20 minutes on a hot plate. After that, it was heated at 300°C in a hot air dryer under a nitrogen atmosphere for 30 minutes (increasing temperature). Speed 5°C/min) to evaporate the solvent to obtain a thin film.

Example 2 The amount of ODPA was changed from 31.021g (0.100 mol) to 24.817g (0.080 mol), and 7.688g (0.020 mol) of CpODA was added, except that the same method as in Example 1 was used to produce polyamide Amine varnish, a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 3 Change the amount of 6FODA from 16.812g (0.0500 mol) to 16.429g (0.04886 mol), and change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 6.950g (0.04886 mol), and add 2.941 g (0.00228 mol) of X-22-9409, except that the polyimide varnish was produced by the same method as in Example 2, and a polyimide varnish with a solid content concentration of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 4 Change the amount of 6FODA from 16.812g (0.0500 mol) to 16.012g (0.04762 mol), and change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 6.774g (0.04762 mol), and add 6.140 g (0.00476 mol) of X-22-9409, except that the polyimide varnish was produced by the same method as in Example 2, and a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 5 Change the amount of ODPA from 31.021g (0.100 mol) to 15.511g (0.050 mol), add 19.219g (0.050 mol) of CpODA, and change the amount of 6FODA from 16.812g (0.0500 mol) to 15.980g ( 0.04753 mol), change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 6.760g (0.04753 mol), and add 6.386g (0.00495 mol) of X-22-9409, except that In addition, a polyimide varnish was produced by the same method as in Example 1, and a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 6 The amount of ODPA was changed from 31.021g (0.100 mol) to 15.511g (0.050 mol), and 11.209g (0.050 mol) of HPMDA was added, except that the same method as in Example 1 was used to produce polyamide Amine varnish, a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 7 Except that CpODA 7.688g (0.020 mol) was changed to HPMDA 4.483 (0.020 mol), a polyimide varnish was produced by the same method as in Example 2, and a polyimide varnish with a solid content of 15% by mass was obtained. Amine varnish. Using the obtained polyimide varnish, a film was obtained in the same manner as in Example 1.

Example 8 Change the amount of 6FODA from 16.812g (0.0500 mol) to 6.725g (0.020 mol), and change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 11.380g (0.080 mol), except that Otherwise, a polyimide varnish was produced by the same method as in Example 6, and a polyimide varnish with a solid content of 15% by mass was obtained. Then, the obtained polyimide varnish was coated on a glass plate by spin coating, and kept at 80°C for 20 minutes on a hot plate. After that, it was heated in a hot air dryer at 240°C for 60 minutes in an air environment to make The solvent evaporates to obtain a thin film.

Example 9 Except that 1,4-BACT 7.113g (0.0500 mol) was changed to 1,3-BAC 7.113g (0.0500 mol), a polyimide varnish was produced by the same method as in Example 1 to obtain a solid Polyimide varnish with a component concentration of 15% by mass. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Example 10 Change the amount of 6FODA from 16.812g (0.0500 mol) to 13.450g (0.0400 mol), and change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 8.535g (0.0600 mol), except that Otherwise, a polyimide varnish was produced by the same method as in Example 6, and a polyimide varnish with a solid content of 15% by mass was obtained. Then, the obtained polyimide varnish was coated on a glass plate by spin coating, and kept at 80°C for 20 minutes on a hot plate. After that, it was heated in a hot air dryer at 260°C for 30 minutes in an air environment. The solvent evaporates to obtain a thin film.

Example 11 Except that 1,4-BACT 7.113g (0.0500 mol) was changed to 1,4-BAC 7.113g (0.0500 mol), a polyimide varnish was produced by the same method as in Example 6 to obtain a solid Polyimide varnish with a component concentration of 15% by mass. Using the obtained polyimide varnish, a film was obtained in the same manner as in Example 10.

Example 12 The amount of 6FODA was changed from 16.812g (0.0500 mol) to 10.087g (0.0300 mol), and 4.966g (0.0200 mol) of 4,4'-DDS was added. Except that, the same method as in Example 6 was used. Methods A polyimide varnish was produced, and a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained in the same manner as in Example 10.

Comparative example 1 Except that 16.812 g (0.0500 mol) of 6FODA was changed to 16.012 g (0.0500 mol) of TFMB, a polyimide varnish was produced by the same method as in Example 1, and a polyimide with a solid content concentration of 15% by mass was obtained. Imine varnish. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Comparative example 2 Change the amount of 6FODA from 16.812g (0.0500 mol) to 33.624g (0.100 mol), and change the amount of 1,4-BACT from 7.113g (0.0500 mol) to 0g (0 mol), except that In addition, a polyimide varnish was produced by the same method as in Example 1, and a polyimide varnish with a solid content of 15% by mass was obtained. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Comparative example 3 Except that 16.812 g (0.0500 mol) of 6FODA was changed to 12.415 g (0.0500 mol) of 3,3'-DDS, a polyimide varnish was produced by the same method as in Example 9 to obtain a solid content concentration of 15 Polyimide varnish of mass%. Using the obtained polyimide varnish, a film was obtained in the same manner as in Example 1.

Comparative example 4 A polyimide varnish was produced by the same method as in Example 1, except that 31.021 g (0.100 mol) of ODPA was changed to 44.424 g (0.100 mol) of 6FDA, and a polyimide with a solid content of 15% by mass was obtained. Imine varnish. Using the obtained polyimide varnish, a film was obtained by the same method as in Example 1.

Comparative example 5 Change ODPA 31.021g (0.100 mol) to HPMDA 22.417g (0.100 mol), change the amount of 6FODA from 16.812g (0.0500 mol) to 33.624g (0.100 mol), and change the amount of 1,4-BACT Except changing from 7.113 g (0.0500 mol) to 0 g (0 mol), a polyimide varnish was produced by the same method as in Example 1, and a polyimide varnish with a solid content concentration of 15% by mass was obtained. . Using the obtained polyimide varnish, a film was obtained in the same manner as in Example 10.

For the polyimide films obtained in the examples and comparative examples, the aforementioned physical property measurement and evaluation were carried out. The results are shown in Table 1.

[Table 1]

As shown in Table 1, it can be seen that the polyimide films of the examples have good optical isotropy, and are also excellent in flexibility and chemical resistance.

Claims (8)

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from a diamine, and the structural unit A includes a structural unit (A-1) derived from a compound represented by the following formula (a-1) , The structural unit B includes the structural unit (B-1) derived from the compound represented by the following formula (b-1) and the structural unit (B-2) derived from the compound represented by the following formula (b-2),

. Such as the polyimide resin of claim 1, wherein the ratio of the structural unit (B-1) in the structural unit B is 5 to 80 mol%, and the ratio of the structural unit (B-2) in the structural unit B is 20 to 95 mole%. Such as the polyimide resin of claim 1 or 2, wherein the molar ratio of the structural unit (B-1) and the structural unit (B-2) in the structural unit B [(B-1)/(B-2) )] is 5/95～80/20. The polyimide resin according to any one of claims 1 to 3, wherein the structural unit A further comprises a structural unit (A-2-1) selected from the compound represented by the following formula (a-2-1) ), and at least 1 from the group consisting of the constituent unit (A-2-2) of the compound represented by the following formula (a-2-2),

. The polyimide resin according to any one of claims 1 to 4, wherein the constituent unit B further comprises a constituent unit selected from the compound represented by the following formula (b-3-1) (B-3-1 ), and at least 1 from the group consisting of the constituent unit (B-3-2) of the compound represented by the following formula (b-3-2),

In formula (b-3-1), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group that may also contain an oxygen atom, and R ¹ and R ² each independently represent a monovalent aromatic group A group or a monovalent aliphatic group, R ³ and R ⁴ each independently represent a monovalent aliphatic group, R ⁵ and R ⁶ each independently represent a monovalent aliphatic group or a monovalent aromatic group, m and n are each independently Ground represents an integer of 1 or more, and the sum of m and n is an integer of 2 to 1000, but ^{at least one of R 1} and R ² represents a monovalent aromatic group. The polyimide resin of claim 5, wherein R ¹ and R ^{2 in} the formula (b-3-1) are phenyl groups. A polyimide varnish made by dissolving the polyimide resin of any one of claims 1 to 6 in an organic solvent. A polyimide film containing the polyimide resin according to any one of claims 1 to 6.