TW202328293A - Polyimide resin, 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 (A1) selected from the group consisting of structural units (A11) derived from a compound represented by formula (a11) below and structural units (A12) derived from a compound represented by formula (a12) below, and a structural unit (A2) derived from a compound represented by formula (a2) below, and the structural unit B includes a structural unit (B1) derived from a compound represented by formula (b1) below.

Description

Polyimide resin, varnish and polyimide film

The present invention relates to polyimide resin, varnish and polyimide film.

Because of its excellent mechanical properties, polyimide resin has been studied for its various applications 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, and polyimide, which is suitable as the plastic material, is also being developed. Resin research. Transparency is also required for polyimide resins used in this way, and further, high heat resistance is also required so that it can cope with high-temperature processing in the manufacturing steps of image display devices.

In addition, in recent years, in the field of microelectronics, laser lift-off processing called laser lift-off (LLO) has attracted attention as a method of peeling the resin film from the support on which the resin film is laminated. . In order to make polyimide film suitable for laser peeling processing, the development of polyimide film with excellent laser peeling property is also carried out.

For example, in Patent Document 1, for the purpose of improving mechanical properties, heat resistance, transparency, dimensional stability, and laser peelability, it is disclosed that a compound derived from norbornane-2-spiro-α-cyclopentanone-α'- Structural units of spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, structural units derived from 2,2'-bis(trifluoromethyl)benzidine, etc. polyimide resin. [Prior Art Literature] [Patent Document]

[Patent Document 1] International Publication No. 2019/065523

[Problem to be Solved by the Invention]

For polyimide films used in image display devices, good optical properties such as colorless transparency are required, and as mentioned above, high heat resistance is also required so that they can cope with high-temperature processing in the manufacturing steps of image display devices. In particular, the TFT device type LTPS (Low Temperature Polysilicon TFT) has a processing temperature exceeding 400°C, and the polyimide used as the substrate requires heat resistance that can withstand several times of high temperature processing above 400°C. Those with high glass transition temperature and high decomposition temperature have excellent short-term heat resistance, but in order to withstand several times or long-term high-temperature treatment as mentioned above, a polyimide film with small weight loss during high-temperature treatment is required. Furthermore, in order to be able to cope with laser peeling processing, laser peelability is also required. In particular, in order to be able to cope with the exfoliation process performed by the XeCl excimer laser with a wavelength of 308nm, the polyimide film is required to have excellent characteristics of absorbing light with a wavelength of 308nm (that is, the light transmittance at a wavelength of 308nm is small). Therefore, the object of the present invention is to provide a polyimide resin, a polyimide varnish, and a polyimide varnish capable of forming a thin film with excellent heat resistance, especially a small weight loss during high-temperature treatment, and excellent laser peelability, and excellent heat resistance, In particular, it is a polyimide film with small weight loss during high temperature treatment and excellent laser peelability. [Means to solve the problem]

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

That is, the present invention relates to the following <1> to <18>. <1> A polyimide resin having a constitutional unit A derived from a tetracarboxylic dianhydride and a constitutional unit B derived from a diamine, wherein the constitutional unit A includes a constitutional unit selected from a compound represented by the following formula (a11) (A11) and at least one structural unit (A1) from the group consisting of a structural unit (A12) derived from a compound represented by the following formula (a12), and a structural unit derived from a compound represented by the following general formula (a2) (A2), the constituent unit B comprises a constituent unit (B1) derived from a compound represented by the following general formula (b1); (In formula (b1), R is each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, a trifluoromethyl group, or a hydroxyl group.) <2> The polyimide resin as in <1>, However, the ratio of the structural unit (B1) in the structural unit B is 15 mol% or more. <3> The polyimide resin according to <1> or <2>, wherein the constituent unit B further includes a constituent unit (B2) derived from a compound represented by the following formula (b2); <4> The polyimide resin according to <3>, wherein the molar ratio [(B1)/(B2)] of the constituent unit (B1) to the constituent unit (B2) in the constituent unit B is 15/85 to 70/30. <5> The polyimide resin according to any one of <1> to <4>, wherein the structural unit (A11) includes a structural unit (A111) derived from a compound represented by the following formula (a111); <6> The polyimide resin according to any one of <1> to <5>, wherein the structural unit (A2) includes a structural unit (A2s) derived from a compound represented by the following formula (a2s); <7> The polyimide resin according to any one of <1> to <6>, wherein the structural unit (B1) includes a structural unit (B11) derived from a compound represented by the following formula (b11); <8> The polyimide resin according to any one of <1> to <7>, wherein the molar ratio of the structural unit (A1) to the structural unit (A2) in the structural unit A is [(A1)/( A2)] is 30/70 to 85/15. <9> A varnish obtained by dissolving the polyimide resin described in any one of <1> to <8> in an organic solvent. <10> An imine-amic acid copolymer comprising a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2); [Chemical 6] (wherein, ^A1 is at least one selected from the group consisting of the group represented by the following formula (3) and the group represented by the following formula (4), and ^A2 is the group represented by the following formula (5); B ¹ and B ² are divalent groups, and any one of B ¹ and B ² includes a group represented by the following formula (6); X ¹ and X ² are each independently a hydrogen atom and an alkane with 1 to 6 carbon atoms group, or an alkylsilyl group with 3 to 9 carbon atoms.) [Chemical 7] <11> A varnish obtained by dissolving the imide-amic acid copolymer described in <10> in an organic solvent. <12> The varnish according to <11>, further comprising an imidazole compound represented by the following general formula (7). [chemical 8] (In formula (7), L ¹ and L ² are each independently a hydrogen atom, an alkyl group with 1 to 6 carbons, a carboxyl group, and a hydroxyl group, and n is an integer of 1 to 4.) <13> a polyimide The resin is obtained by imidizing the amide acid moiety in the amide-amide acid copolymer of <10>. <14> A polyimide film containing the polyimide resin according to any one of <1> to <8> and <13>. <15> For the polyimide film as described in <14>, the weight loss rate after maintaining at 430°C for 1 hour does not reach 1.0%, and the glass transition temperature is above 410°C. <16> The polyimide film according to <14> or <15>, which is used as a transparent substrate constituting a display device. <17> A method for producing a polyimide film, comprising coating a varnish such as <9>, <11> or <12> on a support and heating. <18> An image display device comprising the polyimide film according to any one of <14> to <16> as a transparent substrate. [Effect of Invention]

According to the present invention, it is possible to provide a polyimide resin, a polyimide varnish, and a polyimide varnish capable of forming a film having excellent heat resistance, especially a small weight loss during high temperature treatment, and excellent laser peelability, and excellent heat resistance, especially high temperature. It is a polyimide film with small weight loss during processing and excellent laser peelability.

[Polyimide Resin] The polyimide resin of the present invention has a constituent unit A derived from tetracarboxylic dianhydride and a constituent unit B derived from diamine. The structural unit (A11) of the compound and at least one structural unit (A1) from the group consisting of the structural unit (A12) of the compound represented by the following formula (a12), and the structural unit (A1) derived from the following general formula (a2) In the structural unit (A2) of the compound, the structural unit B includes a structural unit (B1) derived from a compound represented by the following general formula (b1). [chemical 9] (In formula (b1), R is each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, a trifluoromethyl group, or a hydroxyl group.)

In addition, the reason why the polyimide resin of the present invention is excellent in heat resistance, especially the reason why the weight loss is small at the time of high temperature treatment has not yet been determined, but it is thought to be as follows. It is considered that even if some part of the carbon-carbon bond in the multi-alicyclic structure of the polyimide resin of the present invention causes homolytic cleavage due to heat, the generated free radicals are still fixed to the matrix by a plurality of carbon atoms middle. Therefore, it is considered that rebonding occurs, and as a result, it becomes difficult to generate decomposition. It is considered that by such a mechanism, excellent heat resistance is exhibited. In addition, the reason why the polyimide resin of the present invention can form a polyimide film excellent in laser peelability is not yet determined, but it is thought to be as follows. It is considered that not only the structural unit (A1) but also the structural unit (A2) derived from the compound represented by the formula (a2) is included as a structural unit derived from tetracarboxylic dianhydride, whereby absorption of the irradiated laser wavelength can be obtained High, that is, resins with low transmittance. Therefore, it is considered that ablation occurs uniformly at the interface with the glass substrate, and the laser ablation property is excellent.

<Constituent unit A> The structural unit A is the structural unit derived from the tetracarboxylic dianhydride which occupies in a polyimide resin. The constitutional unit A contains at least one composition selected from the group consisting of a constitutional unit (A11) derived from a compound represented by the following formula (a11) and a constitutional unit (A12) derived from a compound represented by the following formula (a12) A unit (A1) and a structural unit (A2) derived from a compound represented by the following general formula (a2). When the structural unit A contains the structural unit (A1) and the structural unit (A2), the heat resistance of a film can be improved. In particular, it can suppress weight loss during high-temperature treatment, and can further improve the laser peelability of the film. [chemical 10]

When the structural unit A contains the structural unit (A1), the heat resistance of the film can be improved. In particular, weight loss during high-temperature treatment can be suppressed. The compound represented by the formula (a11) is decahydro-1,4:5,8-dimethylonaphthalene-2,3,6,7-tetracarboxylic dianhydride (DNDA). When the structural unit A contains the structural unit (A11), the transparency and the heat resistance of the film can be improved. In particular, weight loss during high-temperature treatment can be suppressed. The compound represented by formula (a12) is bicyclooctane-2,3,5,6-tetracarboxylic anhydride (BODA). When the structural unit A contains the structural unit (A12), the transparency and the heat resistance of the film can be improved. In particular, weight loss during high-temperature treatment can be suppressed. The structural unit (A1) preferably includes the structural unit (A11), more preferably the structural unit (A11).

The structural unit (A11) preferably includes a structural unit (A111) derived from a compound represented by the following formula (a111), more preferably a structural unit (A111) derived from a compound represented by the following formula (a111). When the structural unit (A11) contains the structural unit (A111), the transparency and the heat resistance of the film can be improved. In particular, weight loss during high-temperature treatment can be suppressed. In addition, the compound represented by formula (a111) is one type of stereoisomers of the compound represented by formula (a11). [chemical 11]

When the constituent unit A contains the constituent unit (A2), the laser peelability of the film can be improved. The compound represented by formula (a2) is biphenyltetracarboxylic dianhydride (BPDA). Specific examples thereof include 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a2s), and 2,3,3' represented by the following formula (a2a). , 4'-biphenyltetracarboxylic dianhydride (a-BPDA), and 2,2',3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) represented by the following formula (a2i). Among them, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a2s) is preferable. That is, the structural unit (A2) preferably includes a structural unit (A2s) derived from a compound represented by the following formula (a2s), more preferably a structural unit (A2s) derived from a compound represented by the following formula (a2s). [chemical 12]

The molar ratio [(A1)/(A2)] of the constituent unit (A1) to the constituent unit (A2) in the constituent unit A is preferably 30/70 to 85/15, more preferably 50/50 to 85/15, More preferably, it is 55/45 to 85/15, and more preferably, it is 55/45 to 65/35. By setting this molar ratio, transparency and the heat resistance of a film can be improved. In particular, weight loss during high-temperature treatment can be suppressed.

The ratio of the constituent unit (A1) in the constituent unit A is preferably 30-85 mole %, more preferably 50-85 mole %, further preferably 55-85 mole %, still more preferably 55-65 mole % %. The ratio of the constituent unit (A2) in the constituent unit A is preferably 15 to 70 mole%, more preferably 15 to 50 mole%, further preferably 15 to 45 mole%, still more preferably 35 to 45 mole% %. The total ratio of the constituent unit (A1) and the constituent unit (A2) in the constituent unit A is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and is preferably Less than 100 mole%. The structural unit A may consist only of a structural unit (A1) and a structural unit (A2).

The structural unit A may contain structural units other than the structural unit (A1) and the structural unit (A2). There are no particular limitations on tetracarboxylic dianhydrides that give such constituent units, and examples include aromatic tetracarboxylic dianhydrides excluding compounds represented by formula (a2), compounds excluding compounds represented by formula (a11), and excluding compounds represented by formula (a11). (a12) Alicyclic tetracarboxylic dianhydride and aliphatic tetracarboxylic dianhydride of the compound represented. In addition, in this specification, an aromatic tetracarboxylic dianhydride means the tetracarboxylic dianhydride containing one or more aromatic rings, and an alicyclic tetracarboxylic dianhydride means containing one or more alicyclic rings, and The meaning of the tetracarboxylic dianhydride which does not contain an aromatic ring, and the aliphatic tetracarboxylic dianhydride mean the meaning of the tetracarboxylic dianhydride which does not contain an aromatic ring and an alicyclic ring. The structural unit arbitrarily contained in the structural unit A may be 1 type, and may be 2 or more types.

<Constituent Unit B> The structural unit B is a structural unit derived from diamine that occupies in the polyimide resin. Structural unit B contains a structural unit (B1) derived from a compound represented by the following formula (b1). [chemical 13] (In formula (b1), R is each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, a trifluoromethyl group, or a hydroxyl group.)

When the constituent unit B contains the constituent unit (B1), the heat resistance of the film can be improved. In particular, it can suppress weight loss during high-temperature treatment, and can further improve the laser peelability and optical isotropy of the film. In formula (b1), R is each independently at least one selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, a trifluoromethyl group, and a hydroxyl group, preferably hydrogen atom. Specific examples of the compound represented by the formula (b1) include 9,9-bis(4-aminophenyl) fluorine, 9,9-bis(3-fluoro-4-aminophenyl) fluorine, 9,9-bis(3-methyl-4-aminophenyl) fluorene and the like are preferably 9,9-bis(4-aminophenyl) fluorine (BAFL) represented by the following formula (b11). That is, it is preferable that the constitutional unit (B1) includes a constitutional unit (B11) derived from a compound represented by the following formula (b11), and it is more preferable that the constitutional unit (B1) is a constitutional unit (B11) derived from a compound represented by the following formula (b11). ). [chemical 14]

The ratio of the constituent unit (B1) in the constituent unit B is preferably at least 15 mol%, more preferably at least 30 mol%, and more preferably at least 50 mol% in consideration of the laser peelability and heat resistance of the film , more preferably 70 mol % or more, further preferably 80 mol % or more, further preferably 90 mol % or more, further preferably 95 mol % or more, and further preferably 100 mol % or less. The structural unit B may consist only of a structural unit (B1).

The constitutional unit B may consist only of the constitutional unit (B1), and may also contain constitutional units other than the constitutional unit (B1), preferably as a constitutional unit other than the constitutional unit (B1), and further includes a compound represented by the following formula (b2) The constituent unit (B2). [chemical 15] The compound represented by formula (b2) is 2,2'-bis(trifluoromethyl)benzidine (TFMB). When the structural unit B contains the structural unit (B2), the transparency can be improved while maintaining heat resistance.

In the case where the constituent unit B contains the constituent unit (B2), the molar ratio [(B1)/(B2)] of the constituent unit (B1) to the constituent unit (B2) in the constituent unit B is preferably 15/85 to 70/ 30, more preferably 15/85-50/50, more preferably 30/70-50/50, still more preferably 30/70-45/55. By setting this molar ratio, the heat resistance and laser peelability of a film can be improved, and transparency can be improved further.

In the case where the constituent unit B contains the constituent unit (B2), the ratio of the constituent unit (B1) in the constituent unit B is preferably 15 to 70 mole%, more preferably 15 to 50 mole%, and still more preferably 30 to 50 mole%. 50 mol%, more preferably 30-45 mol%. The ratio of the constituent unit (B2) in the constituent unit B is preferably 30-85 mole %, more preferably 50-85 mole %, further preferably 50-70 mole %, still more preferably 55-70 mole % %. The total ratio of the constituent unit (B1) and the constituent unit (B2) in the constituent unit B is preferably at least 50 mol %, more preferably at least 70 mol %, further preferably at least 90 mol %, and is preferably Less than 100 mole%. The structural unit B may consist only of a structural unit (B1) and a structural unit (B2).

The structural unit B may contain structural units other than the structural unit (B1) and the structural unit (B2). There are no particular limitations on the diamines given to such constituent units, but examples include aromatic diamines, alicyclic diamines, and excluding compounds represented by formula (b2), which exclude compounds represented by formula (b11) and Aliphatic diamines. In addition, in this specification, an aromatic diamine means a diamine containing one or more aromatic rings, and an alicyclic diamine means a diamine containing one or more alicyclic rings without an aromatic ring. Diamine means the diamine which does not contain an aromatic ring and does not contain an alicyclic ring. The structural units other than the structural unit (B1) and the structural unit (B2) contained arbitrarily in the structural unit B may be 1 type, and may be 2 or more types.

＜Characteristics of polyimide resin＞ The number average molecular weight of the polyimide resin is preferably 5,000 to 300,000 in view of the mechanical strength of the obtained polyimide film. In addition, the number average molecular weight of a polyimide resin can be calculated|required by the standard polymethylmethacrylate (PMMA) conversion value obtained by gel filtration chromatography measurement, for example.

The polyimide resin may contain structures other than the polyimide chain (the structure in which the structural unit A and the structural unit B are imide-bonded). As a structure other than the polyimide chain which may be contained in a polyimide resin, the structure etc. which contain an amide bond are mentioned, for example. The polyimide resin preferably contains a polyimide chain (a structure in which the constituent unit A and the constituent unit B are imide-bonded) as a main structure. Therefore, the ratio of the polyimide chains in the polyimide resin is preferably at least 50% by mass, more preferably at least 70% by mass, more preferably at least 90% by mass, and still more preferably at least 99% by mass. In addition, it is preferably 100% by mass or less. The polyimide resin may consist only of polyimide chains.

[Manufacturing method of polyimide resin] The method for producing the polyimide resin of the present invention is not particularly limited, and it is preferably any one of the two methods described below. The first production method of the present invention is a method for obtaining a polyimide resin by reacting the compound (tetracarboxylic acid component) imparting the constituent unit A and the compound (diamine component) imparting the constituent unit B above. . By this method, a polyimide resin can be directly obtained from a tetracarboxylic acid component and a diamine component. The second production method of the present invention is to imidize the amide acid moiety in the imide-amic acid copolymer having an imide repeating structural unit and an amic acid repeating structural unit, thereby obtaining a polyamide. imide resin method. Each method will be described below.

＜The first production method of polyimide resin＞ According to this production method, the tetracarboxylic acid component comprising the compound imparting the structural unit (A1) and the compound imparting the structural unit (A2) are reacted with the diamine component comprising the compound imparting the structural unit (B1) , can produce polyimide resin.

As the compound to which the structural unit (A1) is given, the compound represented by the formula (a11) and the compound represented by the formula (a12) can be mentioned, but it is not limited to these, and it can also be derived to the extent that the same structural unit can be given things. As this derivative, the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by formula (a11), and the alkyl ester of this tetracarboxylic acid are mentioned. Among them, tetracarboxylic dianhydride represented by formula (a11) is preferable. Moreover, as this derivative, the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by formula (a12), and the alkyl ester of this tetracarboxylic acid are mentioned. Among them, tetracarboxylic dianhydride represented by formula (a12) is preferable.

Similarly, compounds represented by the formula (a2) may be mentioned as the compound to which the structural unit (A2) is given, but are not limited thereto, and derivatives thereof may be used as long as the same structural unit can be given. As this derivative, the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by formula (a2), and the alkyl ester of this tetracarboxylic acid are mentioned. Among them, tetracarboxylic dianhydride represented by formula (a2) is preferable.

The molar ratio [(A1)/(A2)] of the compound giving the constituent unit (A1) to the compound giving the constituent unit (A2) in the tetracarboxylic acid component is preferably 30/70 to 85/15, more preferably 50 /50-85/15, more preferably 55/45-85/15, more preferably 55/45-65/35.

The ratio of the compound imparting the constituent unit (A1) in the tetracarboxylic acid component is preferably 30 to 85 mol%, more preferably 50 to 85 mol%, further preferably 55 to 85 mol%, and still more preferably 55 mol%. ~65 mole %. The ratio of the compound imparting the constituent unit (A2) in the tetracarboxylic acid component is preferably 15 to 70 mol%, more preferably 15 to 50 mol%, further preferably 15 to 45 mol%, and still more preferably 35 mol%. ~45 mole %. In the tetracarboxylic acid component, the total ratio of the compound imparting the structural unit (A1) and the compound imparting the structural unit (A2) is preferably 50 mol % or more, more preferably 70 mol % or more, and still more preferably 90 mol % The above, and in addition, preferably 100 mol% or less. The tetracarboxylic acid component may consist only of the compound which imparts a structural unit (A1) and the compound which imparts a structural unit (A2).

The tetracarboxylic-acid component may contain tetracarboxylic dianhydride other than the compound given to a structural unit (A1) and the compound given to a structural unit (A2). Such tetracarboxylic dianhydrides are not particularly limited, and examples include aromatic tetracarboxylic dianhydrides excluding compounds represented by formula (a2), compounds represented by formula (a11) and compounds represented by formula (a12). Alicyclic tetracarboxylic dianhydride and aliphatic tetracarboxylic dianhydride. The tetracarboxylic dianhydride contained arbitrarily in the tetracarboxylic acid component may be 1 type, and may be 2 or more types.

Examples of the compound to which the structural unit (B1) is given include compounds represented by the formula (b1), but are not limited thereto, and derivatives thereof may be used as long as the same structural unit can be given. As this derivative, the diisocyanate corresponding to the compound (diamine) represented by formula (b1) is mentioned. Among them, compounds represented by formula (b1) (that is, diamines) are preferable.

The ratio of the compound imparting the constituent unit (B1) in the diamine component is preferably at least 15 mol %, more preferably at least 30 mol %, further preferably at least 50 mol %, still more preferably at least 70 mol % , and further preferably at least 80 mol %, further preferably at least 90 mol %, still more preferably at least 95 mol %, and further preferably at most 100 mol %. The diamine component may consist only of the compound which imparts a structural unit (B1).

The diamine component may contain structural units other than the compound giving the structural unit (B1), and preferably further contains a compound giving the structural unit (B2) derived from the compound represented by the formula (b2).

When the diamine component contains a compound that imparts a structural unit (B2), the molar ratio of the compound that imparts a structural unit (B1) to the compound that imparts a structural unit (B2) in the diamine component [(B1)/(B2) ] is preferably 15/85-70/30, more preferably 15/85-50/50, more preferably 30/70-50/50, further preferably 30/70-45/55.

When the diamine component contains a compound that imparts the structural unit (B2), the ratio of the compound that imparts the structural unit (B1) in the diamine component is preferably 15 to 70 mol%, more preferably 15 to 50 mol%, More preferably, it is 30 to 50 mol%, and still more preferably, it is 30 to 45 mol%. The ratio of the compound to which the constituent unit (B2) is given in the diamine component is preferably 30 to 85 mol %, more preferably 50 to 85 mol %, further preferably 50 to 70 mol %, still more preferably 55 to 55 mol % 70 mole%. In the diamine component, the ratio of the total of the compound imparting the structural unit (B1) and the compound imparting the structural unit (B2) is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 90 mol% The above, and in addition, preferably 100 mol% or less. The diamine component may consist only of the compound which imparts a structural unit (B1) and the compound which imparts a structural unit (B2).

The diamine component may contain diamines other than the compound to give the structural unit (B1) and the compound to give the structural unit (B2). There are no particular limitations on the diamines given to such constituent units, but examples include aromatic diamines, alicyclic diamines, and aliphatic diamines excluding compounds represented by formula (b11) and compounds represented by formula (b2). family of diamines. The diamines other than the structural unit (B1) and the structural unit (B2) contained arbitrarily in the diamine component may be 1 type, and may be 2 or more types.

In the present invention, the addition ratio of the tetracarboxylic acid component and the diamine component used in the manufacture of the polyimide resin is preferably 0.9-1.1 mol of the diamine component relative to 1 mol of the tetracarboxylic acid component.

In addition, in the present invention, in the production of the polyimide resin, a terminal blocking agent may be used in addition to the above-mentioned tetracarboxylic acid component and diamine component. The end-capping agent is preferably monoamine or dicarboxylic acid. The amount of the capping agent to be introduced is preferably 0.0001-0.1 mole, more preferably 0.001-0.06 mole, relative to 1 mole of the tetracarboxylic acid component. In terms of 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 and aniline. The dicarboxylic acid-type end-blocking agent is preferably a dicarboxylic acid, and a part thereof may be ring-closed. Examples include phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, Carboxylic acid, cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc., preferably phthalic acid, o- Phthalic anhydride.

The method of making the said tetracarboxylic-acid component and diamine component react is not specifically limited, A well-known method can be used. As for the specific reaction method, (1) add the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, stir at 0-80°C for 0.5-30 hours, and then raise the temperature to carry out imidization The method of reaction, (2) After adding the diamine component and the reaction solvent into the reactor to dissolve it, add the tetracarboxylic acid component, and stir at room temperature 0-80°C for 0.5-30 hours as required, and then raise the temperature to carry out the imide (3) adding the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, and immediately raising the temperature to carry out the imidization reaction, etc.

The reaction solvent used in the manufacture of polyimide resin is not harmful to the imidization reaction and can dissolve the generated polyimide. Examples thereof include aprotic solvents, phenol-based solvents, ether-based solvents, carbonate-based solvents, and the like.

Specific examples of the aprotic solvent include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), N -Amide-based solvents such as methylcaprolactam, 1,3-dimethylimidazolidinone, and tetramethylurea, lactone-based solvents such as γ-butyrolactone (GBL) and γ-valerolactone, hexa Phosphorus-containing amide-based solvents such as methylphosphoramide and hexamethylphosphinetriamide, sulfur-containing solvents such as dimethylphosphonium, dimethylsulfoxide, and cyclobutylene, acetone, cyclohexanone, methyl Ketone solvents such as cyclohexanone, amine solvents such as picoline and pyridine, ester solvents such as acetic acid (2-methoxy-1-methylethyl ester), and the like.

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, propylene carbonate, and the like. Among the above-mentioned reaction solvents, aprotic solvents are preferred, and amide-based solvents and lactone-based solvents are more preferred. Moreover, the said reaction solvent can be used individually or in mixture of 2 or more types.

Dean-Stark apparatus or the like is preferably used for the imidization reaction, and the reaction is performed while removing water generated during production. By performing such an operation, the degree of polymerization and the imidization rate can be further increased.

In the above imidization reaction, a known imidization catalyst can be used. As an imidization catalyst, an alkali catalyst or an acid catalyst is mentioned. In terms of alkali catalysts, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, trimethylpyridine, Ethylamine (TEA), tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline and other organic base catalysts, hydrogenation Potassium, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate and other inorganic alkali catalysts. In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, Toluenesulfonic acid, naphthalenesulfonic acid, etc. These imidization catalysts may be used individually or in combination of 2 or more types. Among the above, an alkali catalyst is preferably used in consideration of operability, an organic alkali catalyst is more preferably used, and at least one selected from the group consisting of triethylamine and triethylenediamine is further preferably used.

The temperature of the imidization reaction is preferably from 120 to 250°C, more preferably from 160 to 200°C, in consideration of the reaction rate and inhibition of gelation. In addition, the reaction time is preferably 0.5 to 10 hours from the start of distilling off the produced water.

<Manufacturing method of polyimide varnish and polyimide film> The polyimide varnish of the present invention is obtained by dissolving the polyimide resin of the present invention in an organic solvent. That is, the polyimide varnish of the present invention 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 dissolves the polyimide resin, and it is preferable to use the above-mentioned compounds used as reaction solvents in the production of the polyimide resin alone or in combination of two or more. The polyimide varnish of the present invention may be the polyimide solution itself obtained by dissolving the polyimide resin obtained by the polymerization method in the reaction solvent, or may further dilute the polyimide solution with a solvent And the winner.

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 to 40% by mass of the polyimide resin of the present invention, more preferably 10 to 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, surfactants, Various additives such as leveling agent, defoaming agent, fluorescent whitening agent, crosslinking agent, polymerization initiator, photosensitizer, etc. The method for producing the polyimide varnish of the present invention is not particularly limited, and known methods can be used.

The method for producing the polyimide film of the present invention is not particularly limited, and known methods can be used. For example, a method of applying the varnish of the present invention to a support and heating it may be mentioned. Specifically, a method in which organic solvents such as reaction solvents and dilution solvents contained in the varnish are removed by heating after coating on a smooth support such as a glass plate, metal plate, or plastic, and the like.

As a coating method, well-known coating methods, such as spin coating, slit coating, and knife coating, are mentioned. Among them, slit coating is ideal in view of controlling intermolecular alignment and improving chemical resistance and workability. For the method of removing the organic solvent contained in the varnish by heating, it is preferably at a temperature above the boiling point of the organic solvent used after evaporating the organic solvent at a temperature below 150°C to become non-viscosity (not particularly limited, It is preferably 200-500°C) for drying. In addition, drying is preferably carried out under an air atmosphere or a nitrogen atmosphere. The pressure of the dry environment may be any 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, and examples include laser peeling and the method of using a peeling layer (pre-coating a release agent on the surface of the support). method), the method of adding a stripping agent.

<Second production method of polyimide resin> According to this production method, polyimide can be obtained by imidizing the amide acid moiety in the amide-amic acid copolymer having the amide repeating structural unit and the amide acid repeating structural unit. Amine resin. The obtained polyimide resin is the polyimide resin described in the above [polyimide resin], and the ideal range is also the same. The above-mentioned imine-amic acid copolymer will be described below.

<Amide-amic acid copolymer> The imine-amic acid copolymer of the present invention used in this production method is a precursor of polyimide resin, and preferably contains a repeating unit represented by the following formula (1) , and a repeating unit represented by the following formula (2). [chemical 16] (wherein, ^A1 is at least one selected from the group consisting of the group represented by the following formula (3) and the group represented by the following formula (4), and ^A2 is the group represented by the following formula (5). B ¹ and B ² are divalent groups, and any one of B ¹ and B ² includes a group represented by the following formula (6).) [Chem. 17]

In formula (1), A is at least ^one selected from the group consisting of the group represented by formula (3) and the group represented by formula (4), preferably including the group represented by formula (3), more preferably is the base expressed by formula (3). In formula (1) and formula (2), B ¹ and B ² are divalent groups, preferably divalent hydrocarbon groups that may also be substituted, more preferably divalent aromatic hydrocarbon groups that may also be substituted. Any one of ^B1 and ^B2 contains the group represented by the following formula (6), preferably ^B2 contains the group represented by the following formula (6), more preferably ^B1 and ^B2 both contain the group represented by the following formula (6) base. In addition, ^B2 is more preferably a group represented by the following formula (6). In formula (2), X ¹ and X ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbons, or an alkylsilyl group having 3 to 9 carbons.

The molar ratio [(1)/(2)] of the repeating unit represented by formula (1) to the repeating unit represented by formula (2) is preferably 5/95 to 60/40.

(Method for producing imide-amic acid copolymer) The above-mentioned imide-amic acid copolymer is preferably produced by a method having the following steps 1 and 2. Step 1: Reaction of the tetracarboxylic acid component and the diamine component constituting the repeating unit represented by formula (1) to obtain an oligomer having an imide repeating structural unit Step 2: react the oligomer obtained in step 1 with the tetracarboxylic acid component and the diamine component constituting the repeating unit represented by formula (2), to obtain an amide having an imide repeating structural unit and an amic acid repeating structural unit Imine-amic acid copolymer By the production method having the above steps 1 and 2, it is possible to produce a copolymer capable of forming a polyimide film having excellent heat resistance, especially a small weight loss during high temperature treatment, and further excellent laser peelability. Hereinafter, a method for producing an imide-amic acid copolymer will be described.

(tetracarboxylic acid component and diamine component) The tetracarboxylic acid component constituting the repeating unit represented by formula (1) contains at least one selected from the group consisting of compounds represented by formula (a11) and compounds represented by formula (a12). The tetracarboxylic acid component constituting the repeating unit represented by formula (1) preferably includes a compound represented by formula (a11). The tetracarboxylic acid component constituting the repeating unit represented by the formula (1) is more preferably at least one selected from the group consisting of the compound represented by the formula (a11) and the compound represented by the formula (a12), more preferably the compound represented by the formula A compound represented by (a11). The compound represented by formula (a11) preferably includes the compound represented by formula (a111), more preferably the compound represented by formula (a111).

The diamine component constituting the repeating unit represented by formula (1) is not limited, and preferably contains at least one selected from the group consisting of compounds represented by formula (b1) and compounds represented by formula (b2), and more It is preferably a compound represented by formula (b1), and is more preferably a compound represented by formula (b1). The tetracarboxylic acid component and diamine component which comprise the repeating unit represented by formula (1) may contain the tetracarboxylic dianhydride and diamine other than the said compound in the range which does not impair the effect of this invention.

The tetracarboxylic acid component constituting the repeating unit represented by formula (2) includes a compound represented by formula (a2). The tetracarboxylic acid component constituting the repeating unit represented by formula (2) is preferably a compound represented by formula (a2). The compound represented by formula (a2) preferably includes the compound represented by formula (a2s), more preferably the compound represented by formula (a2s).

The diamine component constituting the repeating unit represented by formula (2) is not limited, and preferably contains at least one selected from the group consisting of compounds represented by formula (b1) and compounds represented by formula (b2), more preferably It includes the compound represented by formula (b1), more preferably includes the compound represented by formula (b1) and the compound represented by formula (b2), more preferably includes the compound represented by formula (b1) and the compound represented by formula (b2). In the tetracarboxylic acid component and diamine component which comprise the repeating unit represented by formula (2), you may contain tetracarboxylic dianhydride and diamine other than the said compound in the range which does not impair the effect of this invention.

(solvent) The solvent used in the production of the above-mentioned copolymer may be any solvent as long as it can dissolve the formed copolymer. Specific examples of the reaction solvent are as described in the above [polyimide resin]. Among the above reaction solvents, an amide-based solvent or a lactone-based solvent is preferred, an amide-based solvent is more preferred, and N-methyl-2-pyrrolidone is further preferred. The above reaction solvents may be used alone or in combination of two or more.

(step 1) Step 1 is a step of obtaining an oligomer having an imide repeating structural unit by reacting a tetracarboxylic acid component constituting a repeating unit represented by formula (1) and a diamine component. The tetracarboxylic acid component used in step 1 contains the tetracarboxylic acid component which comprises the repeating unit represented by said formula (1). The diamine component used in step 1 contains the diamine component which comprises the repeating unit represented by formula (1). The addition ratio of the composition used in step 1 is that the molar ratio (diamine/tetracarboxylic acid) of the diamine component relative to the tetracarboxylic acid component should be 0.9～2 moles, more preferably 1.01～2 moles, More preferably, it is 1.05 to 1.9 mol, and still more preferably, it is 1.1 to 1.7 mol.

The method of reacting the tetracarboxylic acid component and the diamine component to obtain the oligomer in step 1 is not particularly limited, and a known method can be used. As for the specific reaction method, it is the same as the description of <the first method of producing polyimide resin>.

In the above imidization reaction, a known imidization catalyst can be used. Specific examples of the imidization catalyst are as described in <The first method for producing polyimide resin>, and the ideal range is also the same.

The temperature of the imidization reaction is preferably from 120 to 250°C, more preferably from 160 to 200°C, in consideration of the reaction rate and inhibition of gelation. In addition, the reaction time is preferably 0.5 to 10 hours from the start of distilling off the produced water.

The oligomer obtained in step 1 has a repeating unit represented by formula (1). The oligomer obtained in step 1 preferably has carboxyl groups at both ends of the main chain of the molecular chain. The carboxyl group mentioned here also includes derivatives. By the above-mentioned method, a solution containing an oligomer dissolved in a solvent is obtained. The solution containing the oligomer obtained in step 1 may contain at least a part of the components used as tetracarboxylic acid components and diamine components in step 1 as unreacted monomers within the range that does not impair the effect of the present invention.

(step 2) Step 2 is to react the oligomer obtained in step 1 with the tetracarboxylic acid component and the diamine component constituting the repeating unit represented by the formula (2), to obtain an amide having an imide repeating structural unit and an amic acid repeating structural unit. The step of imine-amic acid copolymer. The tetracarboxylic acid component used in step 2 contains the above-mentioned tetracarboxylic acid component constituting the repeating unit represented by formula (2). The diamine component used in step 2 contains the diamine component which comprises the repeating unit represented by formula (2). The unreacted tetracarboxylic acid component remaining in the solution containing the oligomer obtained in step 1 can be used as the tetracarboxylic acid component in step 2, or the remaining unreacted tetracarboxylic acid component in the solution containing the oligomer obtained in step 1 The unreacted diamine component was used as the diamine component of step 2. In addition, in step 1, there are amine groups at both ends of the main chain of the molecular chain of the oligomer, and when a compound represented by formula (b1) is used as the diamine component used in step 1, step 2 may also use only Tetracarboxylic acid component.

The method of reacting the oligomer obtained in step 1, the tetracarboxylic acid component and the diamine component constituting the repeating unit represented by formula (2) to obtain the copolymer in step 2 is not particularly limited, and known methods can be used . As far as the specific reaction method is concerned, (1) add the oligomer, diamine component, tetracarboxylic acid component, and solvent obtained in step 1 into the reactor, usually at 0-120°C, preferably at 5-5°C The method of stirring in the range of 80°C for 1 to 72 hours, etc. In the case of reaction below 80°C, the molecular weight of the copolymer obtained in step 2 will not change depending on the temperature history during polymerization, and the progress of thermal imidization can also be suppressed, so the copolymer can be produced stably.

Amide-amic acid copolymer is a copolymer with amide acid repeating structural unit and imide repeating structural unit, and the copolymer is the oligomer obtained in step 1, and the tetracarboxylic acid component in step 2 and Product of polyaddition reaction of diamine component.

By the above method, a copolymer solution containing an imide-amic acid copolymer dissolved in a solvent can be obtained. The concentration of the copolymer in the obtained copolymer solution is usually 1 to 50% by mass, preferably 3 to 35% by mass, more preferably 10 to 30% by mass.

The number average molecular weight of the imide-amic acid copolymer is preferably 5,000 to 500,000 in consideration of the mechanical strength of the obtained polyimide film. In addition, the number average molecular weight of a copolymer can be calculated|required by the standard polymethylmethacrylate (PMMA) equivalent value obtained by gel filtration chromatography measurement, for example.

(Copolymer varnish, method for producing polyimide resin, and method for producing polyimide film) In the second method for producing polyimide resin, the polyimide resin is obtained by imidizing the amide acid moiety in the above-mentioned copolymer which will be the precursor of the polyimide resin, usually A polyimide resin in the form of a film is obtained by subjecting the copolymer solution (varnish) to an imidization reaction and forming it into a film shape. Therefore, in this section, a method for producing a copolymer solution (varnish) and a polyimide film which is a polyimide resin in a film shape will be described. Copolymer varnish is the precursor of polyimide resin, which is obtained by dissolving a copolymer with imide repeating structural unit and amic acid repeating structural unit in an organic solvent. That is, the copolymer varnish contains a copolymer and an organic solvent, and the copolymer is dissolved in the organic solvent. The organic solvent is not particularly limited as long as it dissolves the copolymer, and it is preferable to use the compounds used as solvents in the production of the above-mentioned copolymer alone or in combination of two or more. The copolymer varnish may be the above-mentioned copolymer solution itself, or may be obtained by adding a solvent for dilution to the copolymer solution.

The copolymer varnish can further contain an imidization catalyst and a dehydration catalyst from the viewpoint of making the imidization of the amide acid moiety in the copolymer proceed more efficiently. As the imidization catalyst, an imidization catalyst having a boiling point of 40° C. to 180° C. is preferable, and an amine compound having a boiling point of 180° C. or lower is more preferable. If it is an imidization catalyst with a boiling point of 180° C. or lower, there is no possibility of coloring of the film and impairing the appearance after the film is formed and dried at high temperature. Moreover, if it is an imidization catalyst whose boiling point is 40 degreeC or more, the possibility of volatilization before imidation fully progresses can be avoided. Pyridine or picoline are examples of amine compounds suitable as imidization catalysts. The aforementioned imidization catalysts may be used alone or in combination of two or more. Examples of the dehydration catalyst include acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride; carbodiimide compounds such as dicyclohexylcarbodiimide; and the like. These can be used individually or in combination of 2 or more types.

The copolymer contained in the copolymer varnish has solvent solubility, so it can be made into a high-concentration varnish. The copolymer varnish preferably contains 5 to 40% by mass of the copolymer, more preferably 10 to 30% by mass. The viscosity of the copolymer varnish is preferably 0.1-100Pa･s, more preferably 0.1-20Pa･s. The viscosity of the copolymer varnish is the value measured at 25°C with an E-type viscometer. In addition, the copolymer varnish may also contain inorganic fillers, adhesion promoters, flame retardants, ultraviolet stabilizers, leveling agents, defoamers, fluorescent Various additives other than the above-mentioned resin additives, such as brighteners, crosslinking agents, polymerization initiators, photosensitizers, and adhesion-imparting agents. The method for producing the varnish is not particularly limited, and known methods can be used.

The copolymer varnish preferably further contains an imidazole compound represented by the following general formula (7). [chemical 18] (In formula (7), L ¹ and L ² are each independently a hydrogen atom, an alkyl group with 1 to 6 carbons, a carboxyl group, or a hydroxyl group, and n is an integer of 1 to 4.)

By containing the imidazole compound represented by the above-mentioned general formula (7), it is possible to efficiently obtain the constituent unit A derived from tetracarboxylic dianhydride having the constituent unit (A1) and the constituent unit (A2), and the constituent unit ( B1) A polyimide film composed of a polyimide resin derived from the structural unit B of diamine. The obtained polyimide film is excellent in heat resistance and strength.

In formula (7), ^L1 and ^L2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbons, a carboxyl group, and a hydroxyl group, preferably selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbons. At least one member selected from the group consisting of a hydrogen atom and a methyl group is more preferably at least one member selected from the group consisting of a hydrogen atom and a methyl group, and more preferably a hydrogen atom. Further more preferably, L ¹ is a methyl group and L ² is a hydrogen atom. In formula (7), n is an integer of 1 to 4, preferably an integer of 1 or 2, more preferably 1.

Among the imidazole compounds represented by the above general formula (7), preferably at least one selected from the group consisting of imidazole compounds represented by the following formula (7-1) and imidazole compounds represented by the following formula (7-2) , more preferably an imidazole compound represented by the following formula (7-1). The imidazole compound represented by the following formula (7-1) is 1-benzyl-2-methylimidazole, and the imidazole compound represented by the following formula (7-2) is 1-benzyl imidazole. That is, the imidazole compound represented by the above general formula (7) is preferably at least one selected from the group consisting of 1-benzyl imidazole and 1-benzyl-2-methylimidazole, more preferably 1- Benzyl-2-methylimidazole. [chemical 19]

In the copolymer varnish, the content of the imidazole compound represented by the above formula (7) is preferably 0.1 to 100 parts by mass, more preferably 1.0 to 50 parts by mass, with respect to 100 parts by mass of the imide-amic acid copolymer. It is preferably 4.0 to 40 parts by mass, more preferably 10 to 30 parts by mass.

The method for producing the polyimide film of the present invention is not particularly limited, and known methods can be used. For example, a method of applying the above-mentioned varnish on a support and heating it may be mentioned. Specifically, a method of removing organic solvents such as reaction solvents and dilution solvents contained in the varnish by heating after coating on a smooth support such as a glass plate, a metal plate, or plastic, and the like. In the case of using a copolymer varnish, after removing the organic solvent, it is further heated to carry out imidization. The heating temperature for drying the copolymer varnish to obtain a copolymer film is preferably 50 to 150°C. The heating temperature for imidization by heating the copolymer can be selected from the range of preferably 200 to 500°C, more preferably 250 to 450°C, and still more preferably 300 to 400°C. In addition, the heating time is usually 1 minute to 6 hours, preferably 5 minutes to 2 hours, more preferably 15 minutes to 1 hour. The heating environment can include air, nitrogen, oxygen, hydrogen, nitrogen/hydrogen mixed gas, etc. In order to suppress the coloring of the obtained polyimide resin, nitrogen with an oxygen concentration of 100ppm or less and nitrogen/hydrogen with a hydrogen concentration of 0.5% or less are preferred. hydrogen gas mixture. In addition, the imidization method is not limited to thermal imidization, and chemical imidization can also be used.

The method of peeling the polyimide film formed on the support from the support is not particularly limited, and examples include the laser lift-off method and the method of using a sacrifice layer for peeling (coating a release layer on the surface of the support in advance). The method of molding agent), the method of adding release agent.

[Polyimide film] The polyimide film of the present invention contains the above-mentioned polyimide resin. Therefore, the polyimide film of the present invention has excellent heat resistance, especially a small weight loss during high-temperature treatment, and excellent laser peelability.

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

The polyimide film of the present invention has excellent heat resistance, and especially the weight loss is small during high temperature treatment. The suitable physical property values which the polyimide film of this invention has are as follows. The weight loss rate after maintaining at 430° C. for 1 hour is preferably less than 1.0%, more preferably less than 0.5%, and still more preferably less than 0.3%. The glass transition temperature is preferably 410°C or higher, more preferably 420°C or higher, and still more preferably 430°C or higher. In addition, the said physical property value in this invention can be measured specifically by the method as described in an Example.

The polyimide film of the present invention can be suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members. The polyimide film of the present invention is suitable for use as a substrate of display devices such as liquid crystal displays and OLED displays, and is more suitable for use as a transparent substrate constituting a display device.

[Image display device] The image display device of the present invention comprises the polyimide film of the present invention as a transparent substrate. The image display device of the present invention has, for example, a transparent substrate made of the polyimide film of the present invention, and a display portion provided on the transparent substrate. There are no particular limitations on the display system, and for example, TFT elements, organic EL elements, color filters, LEDs, transistors, electron emission elements, electronic inks, electrophoretic elements, GLV (grid light valve, grating light valve), MEMS (micro electromechanical system, micro electro mechanical system) display elements, using DMD (digital micro mirror device, digital micro mirror device), DMS (digital micro shutter, digital micro shutter), IMOD (interference modulation device, interferometric modulator) components, electrowetting (electrowetting) components, piezoelectric ceramic displays, carbon nanotube display components, etc. As for the image display device of this invention, a liquid crystal display, an OLED display, a touch panel etc. are mentioned, for example. The image display device of the present invention can be manufactured based on known information, except that the polyimide film of the present invention is used as a transparent substrate. The image display device of the present invention uses the polyimide film of the present invention having excellent heat resistance as a transparent substrate, so cracks in the inorganic film and coloring of the transparent substrate are less likely to occur, and the reliability is excellent. [Example]

The present invention will be described in detail below by means of examples. However, the present invention is not limited by these embodiments.

[Film properties and evaluation] The various physical properties of the polyimide films obtained in Examples and Comparative Examples were measured by the methods shown below. In addition, the polyimide film was evaluated by the method shown below. In addition, the polyimide film used for each physical-property measurement and evaluation was performed using the film peeled by the method of following "(8) The minimum energy density which can be peeled off." The film that cannot be peeled off by this method is soaked in water at 40°C for 5 minutes and peeled off. After removing the moisture on the surface with a clean paper, heat it in a hot air dryer at 80°C for 10 minutes in the atmosphere to remove the moisture. After that, it is used in the measurement and evaluation of various physical properties.

(1) Film thickness The film thickness of the polyimide film in the examples and comparative examples is for the polyimide film peeled off from the glass plate, using a contact displacement sensor "SA-S110" manufactured by CITIZEN FINEDEVICE CO., LTD. To measure.

＜Optical properties＞ (2) Total light transmittance, and yellow index (YI) The total light transmittance and YI of the polyimide films of Examples and Comparative Examples are measured for the polyimide films peeled off from the glass plate. The total light transmittance follows JIS K7361-1, and YI follows ASTM E313-05 (D light source, 65°) were all measured using the color and turbidity simultaneous measuring device "COH7700" manufactured by Nippon Denshoku Kogyo Co., Ltd.

(3) Thickness retardation (Rth) (evaluation of optical isotropy) The thickness retardation (Rth) of the polyimide film in Examples and Comparative Examples was measured using an ellipsometer "M-220" manufactured by JASCO Co., Ltd. for the polyimide film peeled from the glass plate. Determination. The value of the thickness retardation was measured at a measurement wavelength of 590nm. In addition, when Rth is set as nx for the largest in-plane refractive index of the polyimide film, ny for the smallest one, nz for the refractive index in the thickness direction, and d for the thickness of the film, the following formula Expresser. Rth=[{(nx+ny)/2}-nz]×d

＜Thermal characteristics (heat resistance)＞ (4) Glass transition temperature (Tg) The glass transition temperature (Tg) of the polyimide film of the Example and the comparative example was calculated|required by the following method using the polyimide film peeled from the glass plate as a test piece. Using the thermomechanical analysis device "TMA 7100C" manufactured by Hitachi High-Tech Corporation, the temperature was raised enough to remove the residual stress under the conditions of the test piece size 4mm×20mm, load 0.1N, and heating rate 10°C/min in tensile mode temperature to remove residual stress, and then cooled to room temperature. After that, the elongation of the test piece was measured under the same conditions as the above-mentioned treatment for removing the residual stress, and the glass transition temperature was obtained by extrapolation of the inflection point of the elongation. (5) 1% weight loss temperature (Td1%) The 1% weight loss temperature (Td1%) of the polyimide film of the Example and the comparative example was obtained by the method mentioned later using the polyimide film peeled off from the glass plate as a sample. A differential thermogravimetric simultaneous measuring device "NEXTA STA200RV" manufactured by Hitachi High-Tech Corporation was used. The sample was heated from 40°C to 150°C at a heating rate of 10°C/min, maintained at 150°C for 30 minutes to remove moisture, and then raised to 550°C at a rate of 10°C/min. The temperature at which the weight decreased by 1% compared with the weight after maintaining at 150° C. for 30 minutes was defined as the 1% weight loss temperature (Td1%). The larger the value of the temperature coefficient of weight loss, the better the heat resistance. (6) Weight reduction rate at 430°C The weight loss rate at 430° C. of the polyimide films of Examples and Comparative Examples was determined by the method described below using the polyimide film peeled off from the glass plate as a sample. A differential thermogravimetric simultaneous measuring device "NEXTA STA200RV" manufactured by Hitachi High-Tech Corporation was used. Raise the temperature of the sample from 40°C to 150°C at a heating rate of 10°C/min, maintain at 150°C for 30 minutes to remove moisture, then raise the temperature to a predetermined temperature (430°C) at a rate of 10°C/min, and maintain at this temperature for 1 hour. The ratio of the weight decreased while maintaining 430° C. for 1 hour to the weight before maintaining 1 hour was defined as the 430° C. weight loss rate. The smaller the coefficient value of the 430° C. weight loss rate, the better the heat resistance.

<Laser lift-off (LLO) peelability> (7) Light transmittance at a wavelength of 308nm The imine thin film was obtained by the method described later. Measurement was performed using an ultraviolet-visible-near-infrared spectrophotometer "UV-3100PC" manufactured by Shimadzu Corporation. The smaller the value of the light transmittance at a wavelength of 308nm, the better the LLO stripping property. In addition, "<0.1" in Table 1 means "less than 0.1%". (8) The minimum energy density that can be peeled is evaluated by irradiating excimer laser (oscillating gas: XeCl, wavelength 308nm) on the glass plate side of the laminate (glass plate/polyimide film) obtained in Examples and Comparative Examples LLO strippability. The LLO conditions are set to overlap 50%, frequency 60Hz, beam size 14mm×1mm, and the energy density is gradually increased by 10mJ/ ^cm2 for laser irradiation, and the minimum energy density that can strip polyimide is measured. The results are shown in Tables 1 and 2. In the examples and comparative examples of this test, AN-wizusFC (0.5mmt) was used as the glass plate. In addition, when the energy density reached 400 mJ/cm ² , the irradiation was terminated, and the evaluation result of those who could not be peeled was "unable to peel". The lower the minimum energy density capable of peeling polyimide, the better the LLO peelability. That is, the efficiency is good and the productivity is good.

<Abbreviation of ingredients, etc.> The tetracarboxylic-acid component and diamine component used in the Example and the comparative example, and its abbreviation are as follows.

(tetracarboxylic acid component) DNDA: (4arH,8acH)-Decahydro-1t,4t:5c,8c-Dimethylonaphthalene-2t,3t,6c,7c-tetracarboxylic dianhydride (manufactured by DAXIN; compound represented by formula (a111)) BODA: Bicyclooctane-2,3,5,6-tetracarboxylic anhydride (manufactured by DAXIN; compound represented by formula (a12)) s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Co., Ltd., compound represented by formula (a2s)) CpODA: norbornane-2-spiro-α-cyclopentanone-α′-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride (manufactured by ENEOS Co., Ltd. )

(diamine component) BAFL: 9,9-bis(4-aminophenyl) terpene (manufactured by JFE Chemical Co., Ltd., compound represented by formula (b11)) TFMB: 2,2'-bis(trifluoromethyl)benzidine (manufactured by SEIKA CORPORATION., compound represented by formula (b2))

The abbreviations of solvents and catalysts used in Examples and Comparative Examples are as follows. GBL: γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) NMP: N-methyl-2-pyrrolidone (manufactured by Tokyo Junyaku Kogyo Co., Ltd.) TEA: Triethylamine (manufactured by Kanto Chemical Co., Ltd.) TEDA: Triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

＜Manufacture of polyimide resin, varnish and polyimide film＞ [Example 1] Add 13.938g (0.040 mole ) of BAFL, 19.214g (0.060 moles) of TFMB, and 93.686g of GBL were stirred at 200rpm at an internal temperature of 70°C under a nitrogen atmosphere to obtain a solution. To this solution, 18.137g (0.060 mol) of DNDA, 11.769g (0.040 mol) of s-BPDA, and 19.908g of GBL were added at once, and then 5.060g of TEA, 0.056g of TEDA and 3.513g of GBL were heated with a heating pack, and the temperature in the reaction system was raised to 190°C for about 20 minutes. While collecting the distilled components and adjusting the rotational speed according to the increase in viscosity, the temperature in the reaction system was maintained at 190° C. and refluxed for 5 hours. After that, 417.978 g of GBL was added, and the temperature inside the reaction system was cooled to 120° C., then stirred for about 3 hours to make it homogenized, and a polyimide varnish with a solid content concentration of 10% by mass was obtained. Then, apply the obtained polyimide varnish to a glass plate, keep it on a hot plate at 80°C for 20 minutes, and then, under a nitrogen atmosphere, heat at 400°C in a hot air dryer for 30 minutes to evaporate the solvent and obtain polyimide imide film. Table 1 shows the physical properties and evaluation results of the film.

[Examples 2 to 7 and Comparative Examples 1 to 5] In Example 1, except having changed the tetracarboxylic-acid component and diamine component into the tetracarboxylic-acid component and diamine component of Table 1, it carried out similarly to Example 1, and obtained the polyimide film. Table 1 shows the physical properties and evaluation results of the film.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative Example 5 Polyimide resin (the number indicates molar ratio) Tetracarboxylic acid component DNDA (a111) 60 60 60 45 70 50 100 100 100 BODA(a12) 45 s-BPDA(a2s) 40 40 40 55 55 30 50 40 30 CpODA 60 70 Diamine component BAFL(b11) 40 20 60 40 40 100 100 40 40 0 100 100 TFMB(b2) 60 80 40 60 60 60 60 100 Polyimide film evaluation - Film thickness [µm] 9.5 8.7 9.5 9.5 8.4 9.1 8.8 9.0 10.1 9.6 9.3 9.2 optical properties Total light transmittance[%] 88.9 89.2 88.7 88.5 88.4 88.2 87.7 89.1 89.8 90.7 88.3 88.8 YI 3.9 3.2 4.4 5.0 4.9 4.8 7.1 3.7 1.1 1.0 4.5 1.1 Rth 326 395 243 381 362 58 90 314 175 327 69 12 thermal properties Tg[°C] 433 423 452 420 418 475 470 414 460 422 450 471 Td1%[℃] 503 484 520 496 507 518 526 471 511 504 502 525 Weight reduction rate[%](430℃) 0.23 0.34 0.17 0.28 0.32 0.20 0.21 2.93 0.62 0.33 1.40 0.25 LLO peelability Light transmittance[%](308nm) 0.1 0.1 0.1 0.1 0.1 <0.1 <0.1 0.1 2.7 28.5 <0.1 0.8 The minimum energy density that can be stripped [mJ/cm ² ] 230 230 220 190 200 230 200 230 Can't peel off Can't peel off 230 Can't peel off

As shown in Table 1, the polyimide film of the example has excellent heat resistance, especially the weight loss during high temperature treatment is small, and the laser stripping property is also excellent.

[Example 8] Add 9.607g (0.030 mole ) of TFMB, 10.454g (0.030 moles) of BAFL, and 84.394g of NMP were stirred at a rotation speed of 200rpm in a nitrogen atmosphere at a temperature of 70°C to obtain a solution. To this solution, after adding 15.114g (0.050 moles) of DNDA and 17.934g of NMP at one time, add 0.253g of TEA as an imidization catalyst, and 3.165g of NMP, and heat it with a heating bag, The temperature in the reaction system was raised to 190° C. for about 20 minutes. While collecting the distilled components, the temperature in the reaction system was maintained at 190° C. and reflux was performed for 1 hour. Thereafter, 98.368 g of NMP was added, the temperature in the reaction system was cooled to 50° C., and a solution containing an oligomer having an imide repeating structural unit was obtained. To the obtained solution, 14.711 g (0.050 mol) of s-BPDA, 12.810 g (0.040 mol) of TFMB, and 39.713 g of NMP were added at once, and stirred at 50° C. for 5 hours. Afterwards, NMP was added and homogenized so that the solid content concentration became about 10% by mass, and further, 1-benzyl-2-imidazole became 15 mass parts with respect to 100 mass parts of imide-amic acid copolymer. 1-benzyl-2-imidazole is added in portions and homogenized to obtain a copolymer (imide-amic acid copolymer) having repeating structural units of imide and repeating structural units of amic acid. varnish. Then, the obtained varnish was coated on a glass plate by spin coating, maintained on a hot plate at 80°C for 20 minutes, and then heated in a hot air dryer at 400°C for 60 minutes in a nitrogen atmosphere to evaporate the solvent to obtain a poly imide film. Table 2 shows the physical properties and evaluation results of the film.

[Table 2] Example 8 Amide-amic acid copolymer (number indicates molar ratio) imide moiety Tetracarboxylic acid component DNDA (a111) 50 Diamine component BAFL(b1) 30 TFMB(b2) 30 Amino acid moiety Tetracarboxylic acid component s-BPDA(a2s) 50 Diamine component TFMB(b2) 40 Additives (numbers represent parts by mass relative to 100 parts by mass of the copolymer) imidazole compound 1-Benzyl-2-imidazole 15 Polyimide film evaluation - Film thickness [µm] 8.7 optical properties Total light transmittance[%] 88.4 YI 5.6 Rth 157 thermal properties Tg[°C] 417 Td1%[℃] 500 Weight reduction rate[%] (430℃) 0.56 LLO peelability Light transmittance[%](308nm) 0.1 The minimum irradiation energy density that can be stripped [mJ/cm ² ] 200

As shown in Table 2, the polyimide film of the example has excellent heat resistance, especially the weight loss during high temperature treatment is small, and the laser stripping property is also excellent.

Claims (18)

A polyimide resin having a constitutional unit A derived from a tetracarboxylic dianhydride and a constitutional unit B derived from a diamine, the constitutional unit A comprising a constitutional unit (A11) selected from a compound represented by the following formula (a11) and at least one structural unit (A1) derived from the group consisting of the structural unit (A12) of the compound represented by the following formula (a12), and the structural unit (A2) derived from the compound represented by the following general formula (a2) , the constituent unit B comprises a constituent unit (B1) derived from a compound represented by the following general formula (b1); In formula (b1), R is each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, a trifluoromethyl group, or a hydroxyl group. The polyimide resin according to claim 1, wherein the ratio of the constituent unit (B1) in the constituent unit B is 15 mol% or more. The polyimide resin as claimed in claim 1 or 2, wherein the constituent unit B further comprises a constituent unit (B2) from a compound represented by the following formula (b2); . The polyimide resin according to claim 3, wherein the molar ratio [(B1)/(B2)] of the constituent unit (B1) to the constituent unit (B2) in the constituent unit B is 15/85 to 70/30 . The polyimide resin according to any one of claims 1 to 4, wherein the constituent unit (A11) comprises a constituent unit (A111) derived from a compound represented by the following formula (a111); . The polyimide resin according to any one of claims 1 to 5, wherein the constituent unit (A2) comprises a constituent unit (A2s) derived from a compound represented by the following formula (a2s); . The polyimide resin according to any one of claims 1 to 6, wherein the constituent unit (B1) comprises a constituent unit (B11) derived from a compound represented by the following formula (b11); . The polyimide resin according to any one of claims 1 to 7, wherein the molar ratio [(A1)/(A2)] of the constituent unit (A1) to the constituent unit (A2) in the constituent unit A is 30 /70～85/15. A varnish, which is formed by dissolving the polyimide resin according to any one of claims 1 to 8 in an organic solvent. A kind of imine-amic acid copolymer, containing the repeating unit represented by following formula (1) and the repeating unit represented by following formula (2); In the formula, ^A1 is at least one selected from the group consisting of the group represented by the following formula (3) and the group represented by the following formula (4), and ^A2 is the group represented by the following formula (5); B ¹ and ^B2 are divalent groups, and any one of B1 ^{and B2} includes a group represented by the following formula (6); ^X1 and ^X2 are each independently a hydrogen atom and an alkyl group with 1 to 6 carbon atoms , or an alkylsilyl group with 3 to 9 carbon atoms; . A varnish, which is formed by dissolving the imide-amic acid copolymer in claim 10 in an organic solvent. The varnish as claimed in item 11 further contains an imidazole compound represented by the following general formula (7); In formula (7), L ¹ and L ² are each independently a hydrogen atom, an alkyl group having 1-6 carbons, a carboxyl group, or a hydroxyl group, and n is an integer of 1-4. A polyimide resin, which is formed by imidizing the amide acid part in the amide-amide acid copolymer as claimed in claim 10. A polyimide film containing the polyimide resin according to any one of Claims 1 to 8 and 13. For example, the polyimide film of claim 14 has a weight loss rate of less than 1.0% after being maintained at 430°C for 1 hour, and a glass transition temperature of 410°C or higher. The polyimide film as claimed in claim 14 or 15, which is used as a transparent substrate constituting a display device. A method for producing a polyimide film, comprising coating the varnish according to claim 9, 11 or 12 on a support and heating. An image display device comprising the polyimide film according to any one of Claims 14 to 16 as a transparent substrate.