JP2013082774A - Transparent polyimide film and production process thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide film useful as a film material for products or part of the member thereof for which transparency and heat resistance are required.SOLUTION: A polyamide acid having a periodic structure is synthesized by polymerizing a unit containing an alicyclic structure and a unit not containing an alicyclic structure separately, mixing them, and reacting their terminals. The polyimide film having a high light transmittance, low turbidity and yellowing and excellent transparency and heat resistance is obtained by producing a film from the polyamide acid.

Description

  The present invention relates to a transparent polyimide film having heat resistance and high transparency and less turbidity and yellowness.

  In recent years, with the rapid progress of displays such as liquid crystal, organic EL, and electronic paper, and electronics such as solar cells and touch panels, devices have been required to be thinner and lighter, and more flexible. . In these devices, various electronic elements such as thin transistors and transparent electrodes are formed on a glass plate. By changing this glass material to a film material, the panel itself becomes flexible, thin and lightweight. Can be achieved. However, there has been no film material that can withstand the high temperature of the formation process of electronic devices.

  Since polyimide has high insulation performance and heat resistance, it has been applied to semiconductors and electronic components. In order to improve the physical properties of this polyimide, it is conceivable to mix polyimides with different properties. However, since polyimide has a large molecular cohesive force, it is easy to obtain a phase separation structure with a simple blend, and the transparency is impaired. There was a problem.

  On the other hand, Patent Document 1 proposes a polyimide mixed film in which polyimides are gently entangled and bonded in order to suppress phase separation. However, in this method, the principle has not been elucidated, so that there has been a problem that phase separation cannot always be suppressed.

  In addition, Patent Document 2 discloses a novel polyimide copolymer having an alicyclic structure. However, the effect of improving the transparency by individually polymerizing amic acid is also disclosed. Not.

  As described above, there has been no transparent, colorless and heat-resistant plastic film that can be used for liquid crystal, organic EL, electronic paper and other displays, solar cells, touch panels, and the like. It has been a factor that hinders improvement in breakage resistance, thinning and weight reduction, and further flexibility.

JP 2001-240744 A JP 2003-155342 A

  The present invention has been accomplished in view of the above circumstances, and an object thereof is to obtain a polyimide film having excellent heat resistance and transparency.

  The configuration of the present invention is as follows.

  1). A transparent polyimide film having a unit containing an alicyclic structure and a unit not containing an alicyclic structure in the same molecular chain.

  2). The transparent polyimide film according to 1), wherein a unit containing an alicyclic structure and a unit not containing an alicyclic structure are individually polymerized.

  3). By reacting a unit containing an alicyclic structure and a unit not containing an alicyclic structure with each other, a periodic copolymer in which each unit is alternately arranged in the same molecular chain is formed 1) Or the transparent polyimide film as described in 2).

  4). The transparent polyimide film according to any one of 1) to 3), wherein the unit containing an alicyclic structure comprises an acid dianhydride having an alicyclic structure and an aromatic diamine.

  5). The transparent polyimide film according to any one of 1) to 4), wherein a unit containing an alicyclic structure is represented by the following formula (1).

In the general formula, R ¹ represents a tetravalent organic group selected from the following general formula (2).

6). The transparent polyimide film according to 5), wherein the repeating unit represented by the general formula (1) is a tetravalent organic group in which the structure of R ¹ is selected from the following formula (3).

  7). The transparent polyimide film according to any one of 1) to 6), wherein a unit not containing an alicyclic structure is represented by the following general formula (4).

In the general formula, R ² represents a tetravalent organic group selected from the following formula (5).

8). The transparent polyimide film according to 7), wherein the repeating unit represented by the general formula (4) is a tetravalent organic group in which the structure of R ² is selected from the following general formula (6).

  9). The transparent polyimide film according to any one of 1) to 8), wherein the total light transmittance is 80% or more and YI is 20 or less.

  10). The transparent polyimide film according to any one of 1) to 9), wherein the transmittance at a light wavelength of 400 nm is 15% or more and the transmittance at a light wavelength of 420 nm is 40% or more.

  11). Any one of 1) to 10), wherein a polyamic acid obtained by reacting a unit containing an alicyclic structure and a unit not containing an alicyclic structure is imidized using an imidizing agent and a dehydrating catalyst. The transparent polyimide film of crab.

  12). 11. The transparent polyimide film according to 11), wherein the addition amount of the dehydrating agent is the dehydrating agent mole number / the amide group mole number in the polyamic acid = 10 to 0.01.

  13). The transparent polyimide film according to 11) or 12), wherein the amount of the imidizing agent added is imidizing agent / mole number of amide groups in polyamic acid = 10 to 0.01.

  14). The method for producing a transparent polyimide film according to any one of 1) to 13), comprising a unit containing an alicyclic structure and a unit not containing an alicyclic structure.

  According to the present invention, since a transparent polyimide film having excellent heat resistance and transparency and less turbidity and yellowness can be obtained, it can be used in fields and products where heat resistance and transparency are effective.

The present invention is described in detail below.
The present invention is a transparent copolymer composed of a cyclic copolymer in which units obtained by reacting after a unit containing an alicyclic structure and a unit not containing an alicyclic structure are separately bonded to each other. It is a polyimide film.
The polyimide film manufactured by this invention is a repeating unit represented by the unit which has an alicyclic structure shown by General formula (1), and / or the unit which does not have an alicyclic structure shown by General formula (4). A polyimide film containing

R ¹ in the general formula (1) is a tetravalent organic group having a specific structure selected from the general formula (2).

Of the tetravalent organic groups listed in general formula (2), cyclohexane or bicyclohexane shown in general formula (3) is particularly preferable.

The polyimide fill containing the repeating unit of the general formula (1) and / or (4) includes an acid dianhydride compound having a structure of R ¹ or R ² and, for example, 2,2′-bis (trifluoromethyl) benzidine ( Polyamide acid unit containing an alicyclic structure and a polyamic acid unit not containing an alicyclic structure are synthesized using a diamine having a specific structure having a methyl trifluoride group such as TFMB), and then both units are reacted. The polyamic acid periodic copolymer (block copolymer) obtained in this way can be obtained by imidization.

  Specific examples of the acid dianhydride having cyclohexane or biscyclohexane include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,1′-bicyclohexane-3,3 ′, 4,4. '-Tetracarboxylic dianhydride is mentioned.

  The general formula (1) is preferably produced using an acid dianhydride having the entire acid component having the structure of the general formula (2), but not only the structure of the general formula (2) but also one or more types. An acid dianhydride having no general formula (2) can be used in combination. Other acid dianhydrides that can be used in combination without having the structure of the general formula (2) may be used within a range not exceeding 70 mol%, preferably 50 mol%, or even 25 mol% of the acid dianhydride. . When using 2 or more types of acid dianhydrides, they may be regularly arranged or may be present in the polyimide randomly.

  Other acid dianhydrides that can be used in combination include, for example, ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 3, 3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether Dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3 Dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3 Hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 1,3-bis [(3 , 4-Dicarboxy) benzoyl] benzene dianhydride, 1,4-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 2,2-bis {4- [4- (1,2- Dicarboxy) phenoxy] phenyl} propane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, bis {4- [4- (1, 2-Dicarboxy) phenoxy] pheni } Ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, 4,4′-bis [4- (1,2-dicarboxy) phenoxy] biphenyl Dianhydride, 4,4′-bis [3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride Bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, Bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, bis { 4- [3- (1 , 2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3,3,3 -Hexaflupropane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3,3,3-propane dianhydride, 2 , 3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2 , 3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7 , 8-Phenanthrenetetracarboxylic dianhydride And the like.

R ² in general formula (4) is a tetravalent organic group having a specific structure listed in general formula (5).

Two or more kinds of acid dianhydrides having a tetravalent organic group listed in general formula (5) can be used in combination. Of the tetravalent organic groups listed in general formula (5), benzene or biphenyl shown in general formula (6) is particularly preferable.

  Specific compounds having benzene or biphenyl may include pyromellitic dianhydride and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, respectively. Among them, 3,3 ′ 4,4′-biphenyltetracarboxylic dianhydride is preferred.

  In the general formula (4), it is preferable that all the acid dianhydride components to be used are produced using an acid dianhydride having the structure of the general formula (5), but not only the structure of the general formula (5). One or more acid dianhydrides having no structure of the general formula (5) can be used in combination. Other acid dianhydrides that can be used in combination without having the structure of the general formula (5) may be used within a range not exceeding 70 mol%, preferably 50 mol%, and further not exceeding 25 mol% of the acid dianhydride. . When using 2 or more types of acid dianhydrides, they may be regularly arranged or may be present in the polyimide randomly.

  Examples of other acid dianhydrides that can be used in combination include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) ) Propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) Ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl)- 1,1 1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, , 3-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 1,4-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 2,2-bis {4- [ 4- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, bis {4 -[4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, 4,4′- Bis [4- (1,2-dicarboxy) phenol Noxy] biphenyl dianhydride, 4,4′-bis [3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} Ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfone Anhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride Bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} -1 , 1,1 , 3,3,3-hexaflupropane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3,3,3- Propane dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic acid Anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride 1,2,7,8-phenanthrenetetracarboxylic dianhydride and the like.

The ratio of R ¹ in the general formula (1) and R ^{2 in} the general formula (4) is preferably 95 to 15: 5 to 85. Furthermore, 85-35: 15-65 are preferable. Among these, it is preferable that R ¹ exceeds 50 in terms of transmittance and YI. Among them, the ratio of R ¹ and R ² is preferably 85 to 65:15 to 35, and particularly preferably 85 to 75:15 to 25.

  As a method for producing the polyimide of the present invention, a method of synthesizing a polyamic acid which is a precursor from an acid dianhydride and a diamine, and adding a dehydrating agent or an imidizing agent thereto to obtain a polyimide film, or polyamic acid There is a method of forming in a state and then imidizing by heating without using a dehydrating agent or an imidizing agent. Among them, the method of obtaining a polyimide film by adding a dehydrating agent or an imidizing agent is preferable for controlling the moldability and physical properties of the film.

  As the imidizing agent, tertiary amines such as aliphatic tertiary amines, aromatic tertiary amines, and heterocyclic tertiary amines are preferably used. Among these, it is preferable to use any one of pyridine, picoline, isoquinoline, and diethylpyridine. These catalysts are preferably used alone or in combination.

  Examples of the dehydrating agent include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides such as phthalic anhydride. These dehydrating agents are preferably used alone or in combination. Of these, aliphatic acid anhydrides are preferred from the standpoints of cost, availability, and solubility.

  About the addition amount of a dehydrating agent and an imidizing agent, the dehydrating agent mole number / mole number of amide groups in polyamic acid = 10 to 0.01 is preferable, and the imidizing agent / mole number of amide groups in polyamic acid = 10 to 0.01. Is preferred. More preferably, the number of moles of dehydrating agent / the number of moles of amide groups in the polyamic acid is preferably 5 to 0.5, and the number of moles of amide groups in the imidizing agent / polyamic acid is preferably 5 to 0.5.

  It is preferable to mix the dehydrating agent and the imidizing agent directly into the polyamic acid. In the method of immersing a polyamic acid film in a solution of a dehydrating agent or imidizing agent, it takes time for the dehydrating agent or imidizing agent to permeate the entire film, and the imidation rate at the surface and in the deep part is different and uneven. It becomes difficult to obtain the polyimide film according to the present invention.

  Although it is possible to obtain a film having a total light transmittance of 80% or more of the polyimide film according to the present invention, it is 83% or more and further 86 by optimizing the amount of dehydrating agent and chemical imidizing agent and baking conditions. % Film or more can also be obtained. If the total light transmittance is low, the transparency of the film may be impaired. The light transmittance can be maintained when the thickness of the polyimide film is in the range of about 5 to 200 μm.

  Although it is possible to obtain a film having a haze of 20% or less according to the present invention, it is 15% or less, more preferably 10% or less, by optimizing the amount of dehydrating agent and chemical imidizing agent and baking conditions. It is also possible to obtain a film. If the haze is high, the transparency of the film may be impaired. The haze can be maintained when the thickness of the polyimide film is in the range of about 5 to 200 μm.

  The polyimide film according to the present invention can obtain a film having light transmittances of 15% or more and 40% or more at wavelengths of 400 nm and 420 nm, respectively. It is also possible to obtain films of 18% or more and 45% or more, respectively 20% or more and 50% or more, respectively, by optimizing the above. If the transmittance at 400 nm and 420 nm is low, the transparency of the film may be impaired. The transmittance at 400 nm and 420 nm can be maintained when the thickness of the polyimide film is in the range of about 5 to 200 μm. In addition, the polyimide film according to the present invention can have good transmittance at 400 nm and 420 nm as described above.

  Although it is possible to obtain a film having a YI (yellow index) of 20 or less of the polyimide film according to the present invention, it is also possible to obtain a film of 18 or less or even 15 or less by optimizing the baking conditions. . When YI is high, a film may become yellow and transparency may be impaired.

Next, the method for synthesizing the polyimide according to the present invention will be illustrated more specifically, but the present invention is not limited thereto.
For example, 1,1′-bicyclohexane-3,3 ′, 4,4′-tetracarboxylic dianhydride (BPDA-H) as an acid component of a unit containing an alicyclic structure, for example, 2,2 ′ as a diamine component An example of synthesizing polyimide using bis (trifluoromethyl) benzidine (TFMB) will be described. First, while stirring dimethylacetamide (DMAc) in which TFMB is dissolved, BPDA-H less than the number of moles of TFMB is gradually added to obtain an amine-terminated polyamic acid.

  For example, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) as an acid component of a unit not containing an alicyclic structure, and for example, 2,2′-bis (trifluoromethyl) benzidine as a diamine component An example of synthesizing polyimide using (TFMB) will be described. First, while stirring DMAc in which TFMB is dissolved, BPDA larger than the number of moles of TFMB is gradually added to obtain an acid-terminated polyamic acid.

  After the polyamic acid of the unit containing the obtained alicyclic structure and the polyamic acid of the unit not containing the alicyclic structure are mixed, the polyamic acid of the periodic copolymer is obtained, and the temperature is lowered to 0 ° C. or lower. It can be obtained by adding an imidizing agent, a dehydrating agent and a DMAc solution and stirring vigorously.

  The polyamic acid obtained as described above can be applied onto a substrate such as glass, film, or belt, dried, formed into a coating film, and heated to obtain a film-like polyimide.

In performing application or the like on the substrate, the polyamic acid is preferably degassed under vacuum or using a centrifugal precipitator or the like.
In heating, for example, a film-like polyimide can be obtained by heating in the range of 200 ° C. to 400 ° C., further 220 to 350 ° C., particularly 240 to 320 ° C. When the heating temperature exceeds 400 ° C., molecular rearrangement occurs in the film, crystallization is accelerated, and the transparency of the film may not be ensured. Moreover, since the solvent in a film may not completely volatilize when heating temperature is 200 degrees C or less, it is preferable to avoid.

[Evaluation of YI]
It measured using Nippon Denshoku Industries Co., Ltd. Spectro Color Meter SE-2000.

[Evaluation of haze and total light transmittance]
The test was carried out using NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd. The measurement was performed three times, and the average value was taken as the measured value of the film.

[Evaluation of transmittance at 420 nm]
It measured using the JASCO Corporation ultraviolet visible spectrophotometer V-560.

[Create film]
After the polyamic acid solution obtained by the synthesis of the precursor solution was brought to 0 ° C., a mixed solution consisting of acetic anhydride / β-picoline / DMAc (weight ratio 35/7/8) (dehydrating agent / mole amide group in polyamic acid Number = 3.75, imidizing agent / mole number of amide groups in polyamic acid = 0.75) with respect to the polyamic acid solution, 35% by weight, and vigorously stirred while maintaining at 0 ° C. Casted. After heating this resin film at 100 ° C. for 10 minutes, the self-supporting gel film is peeled off from the aluminum foil and fixed to the tenter clip, and dried at 100 ° C. for 10 minutes, 200 ° C. for 10 minutes, 250 ° C. for 30 minutes. -Imidized to obtain a polyimide film having a thickness of 50 μm.

Example 1 (BPDA / BPDA-H / TFMB = 60/40/100)
TFMB 5.2 g (16.2 mmol) was put into a 100 ml separable flask, dissolved in 32 g of dehydrated DMAc, and stirred under cooling in an ice bath under a nitrogen stream. BPDA 5.5g (18.7mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and precursor solution A1 was obtained.

TFMB 4.8 g (15.0 mmol) was put into a 100 ml separable flask, dissolved in 26 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA-H3.8g (12.4mmol) was added there, and it stirred at 100 degreeC for 10 minutes, and then stirred at room temperature for 1 hour, and precursor solution B1 was obtained.
The obtained precursor solutions A1 and B1 were mixed at room temperature for 40 hours to obtain a polyamic acid as a periodic copolymer, which was formed into a film by the above film preparation method, and the physical properties were measured. The results are shown in Table 1.

Example 2 (BPDA / BPDA-H / TFMB = 30/70/100)
1.6 g (5.0 mmol) of TFMB was put into a 100 ml separable flask, dissolved in 13 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. Thereto, 2.8 g (9.5 mmol) of BPDA was added, and after completion of the addition, the mixture was stirred for 40 hours to obtain a precursor solution A2.

  TFMB 8.4 g (26.2 mmol) was put into a 100 ml separable flask, dissolved in 45 g of dehydrated DMAc, and stirred under cooling in an ice bath under a nitrogen stream. Thereto was added 6.7 g (21.9 mmol) of BPDA-H, and the mixture was stirred at 100 ° C. for 10 minutes and then at room temperature for 1 hour to obtain a precursor solution B2.

  The obtained precursor solutions A2 and B2 were mixed as described above to obtain a polyamic acid as a periodic copolymer, formed into a film by the above-mentioned film preparation method, and measured for physical properties. The results are shown in Table 1.

Example 3 (BPDA / BPDA-H / TFMB = 20/80/100)
TFMB 0.8 g (2.5 mmol) was put into a 100 ml separable flask, dissolved in 7 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA 1.5g (5.1mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and precursor solution A3 was obtained.

TFMB (7.2 g, 22.5 mmol) was put into a 100 ml separable flask, dissolved in 40 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA-H6.1g (19.9 mmol) was added there, and it stirred at 100 degreeC for 10 minutes, Then, it stirred at room temperature for 1 hour, and precursor solution B3 was obtained.
The obtained precursor solutions A3 and B3 were mixed as described above to obtain a polyamic acid as a periodic copolymer, which was formed into a film by the above film preparation method, and the physical properties were measured. The results are shown in Table 1.

Comparative Example 1 (BPDA / BPDA-H / TFMB = 60/40/100)
4.5 g (14.1 mmol) of TFMB was put into a 100 ml separable flask, dissolved in 17 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA4.1g (14.1mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and precursor solution A4 was obtained.

3 g (9.4 mmol) of TFMB was put into a 100 ml separable flask, dissolved in 19 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA-H2.9g (9.4mmol) was added there, and it stirred at 100 degreeC for 10 minutes, Then, it stirred at room temperature for 1 hour, and precursor solution B4 was obtained.
After the obtained precursor solutions A4 and B4 were mixed as described above, they were formed into a film by the above-mentioned film preparation method, and the physical properties were measured. The results are shown in Table 1.

Comparative Example 2 (BPDA / BPDA-H / TFMB = 30/70/100)
4.5 g (14.0 mmol) of TFMB was put into a 100 ml separable flask, dissolved in 17 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA4.2g (14.0mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and precursor solution A5 was obtained.

10.5 g (32.7 mmol) of TFMB was put into a 100 ml separable flask, dissolved in 44 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. Thereto, 10.0 g (32.7 mmol) of BPDA-H was added, stirred at 100 ° C. for 10 minutes, and then stirred at room temperature for 1 hour to obtain a precursor solution B5.
After the obtained precursor solutions A5 and B5 were mixed as described above, they were formed into a film by the film preparation method, and the physical properties were measured. The results are shown in Table 1.

Comparative Example 3 (BPDA / BPDA-H / TFMB = 20/80/100)
TFMB 2.2 g (7.0 mmol) was put into a 100 ml separable flask, dissolved in 9 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA 2.1g (7.0 mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and precursor solution A6 was obtained.

TFMB 9.0 g (28.0 mmol) was put into a 100 ml separable flask, dissolved in 38 g of dehydrated DMAc, and stirred under cooling in an ice bath under a nitrogen stream. Thereto was added 8.6 g (28.0 mmol) of BPDA-H, and the mixture was stirred at 100 ° C. for 10 minutes and then at room temperature for 1 hour to obtain a precursor solution B.
After the obtained precursor solutions A6 and B6 were mixed as described above, they were formed into a film by the film preparation method, and the physical properties were measured. The results are shown in Table 1.

Comparative Example 4 (BPDA / TFMB = 100/100)
TFMB 10.0 g (31.2 mmol) was put into a 100 ml separable flask, dissolved in 40 g of dehydrated DMAc, and stirred while cooling in an ice bath under a nitrogen stream. BPDA9.2g (31.2 mmol) was added there, and it stirred for 40 hours after completion | finish of addition, and obtained the precursor solution.
The obtained precursor solution was formed into a film by the above film preparation method, and the physical properties were measured. The results are shown in Table 1.

  From the results in Table 1, since the polyimide film of the present invention is a film having good heat resistance and transparency, fields and products in which these characteristics are effective, for example, inorganic thin films and inorganic microstructures on the surface It can be applied to a film member having, for example, a film for a thin film transistor formed from silicon, a metal oxide, or an organic material, a color filter film, a film with a transparent electrode, a gas barrier film, a film in which inorganic glass or organic glass is laminated. These members are suitable for, for example, films for liquid crystal displays, films for organic EL, films for electronic paper, films for solar cells, films for touch panels, and the like.

Claims (14)

A transparent polyimide film having a unit containing an alicyclic structure and a unit not containing an alicyclic structure in the same molecular chain. The transparent polyimide film according to claim 1, wherein a unit containing an alicyclic structure and a unit not containing an alicyclic structure are individually polymerized. The periodic copolymer in which each unit is alternately arranged in the same molecular chain is formed by reacting a unit containing an alicyclic structure and a unit not containing an alicyclic structure with each other. The transparent polyimide film according to 1 or 2. The transparent polyimide film according to any one of claims 1 to 3, wherein the unit containing an alicyclic structure comprises an acid dianhydride having an alicyclic structure and an aromatic diamine. The transparent polyimide film according to any one of claims 1 to 4, wherein the unit containing an alicyclic structure is represented by the following formula (1).

In the general formula, R ¹ represents a tetravalent organic group selected from the following general formula (2).

The transparent polyimide film according to claim 5, wherein the repeating unit represented by the general formula (1) is a tetravalent organic group in which the structure of R ¹ is selected from the following formula (3).

The transparent polyimide film according to any one of claims 1 to 6, wherein the unit not containing an alicyclic structure is represented by the following general formula (4).

In the general formula, R ² represents a tetravalent organic group selected from the following formula (5).

The transparent polyimide film according to claim 7, wherein the repeating unit represented by the general formula (4) is a tetravalent organic group in which the structure of the R ² is selected from the following general formula (6). .

The transparent polyimide film according to any one of claims 1 to 8, wherein the total light transmittance is 80% or more and YI is 20 or less. The transparent polyimide film according to any one of claims 1 to 9, wherein the transmittance at a light wavelength of 400 nm is 15% or more and the transmittance at a light wavelength of 420 nm is 40% or more. The imidization agent and dehydration catalyst are used to imidize polyamic acid obtained by reacting a unit containing an alicyclic structure and a unit not containing an alicyclic structure, according to any one of claims 1 to 10 The transparent polyimide film of crab. The transparent polyimide film according to claim 11, wherein the addition amount of the dehydrating agent is the dehydrating agent mole number / the amide group mole number in the polyamic acid = 10 to 0.01. The transparent polyimide film according to claim 11 or 12, wherein an addition amount of the imidizing agent is imidizing agent / mole number of amide groups in polyamic acid = 10 to 0.01. The method for producing a transparent polyimide film according to claim 1, comprising a unit containing an alicyclic structure and a unit not containing an alicyclic structure.