JP6016561B2 - POLYIMIDE PRECURSOR, RESIN COMPOSITION CONTAINING THE SAME, POLYIMIDE FILM AND ITS MANUFACTURING METHOD, AND LAMINATE AND ITS MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to, for example, a polyimide precursor and a resin composition containing the polyimide precursor, a polyimide film and a manufacturing method thereof, and a laminate and a manufacturing method thereof, which are used for a substrate for a flexible device.

  Generally, a polyimide (PI) film is a polyimide resin film. Polyimide resin is a solution polymerization of an aromatic dianhydride and an aromatic diamine, and after producing a polyimide precursor, ring closure dehydration at high temperature, thermal imidization, or chemical imidization using a catalyst, It is a highly heat-resistant resin that is manufactured.

  Polyimide resin is an insoluble and infusible super heat-resistant resin, and has excellent characteristics such as heat oxidation resistance, heat resistance, radiation resistance, low temperature resistance, chemical resistance, etc. It is used in a wide range of fields including electronic materials such as films, semiconductors, and electrode protection films for TFT-LCDs, and recently, it is also used for display materials such as optical fibers and liquid crystal alignment films.

  However, polyimide resins are colored brown or yellow due to high aromatic ring density, have low transmittance in the visible light region, and have been difficult to use in fields where transparency is required.

  Patent Document 1 reports that a polyimide having a novel structure in which transmittance and hue transparency are improved by using an acid dianhydride and a diamine containing a specific structure.

JP 2000-198843 A

  However, the mechanical characteristics and thermal characteristics of polyimide described in Patent Document 1 are not sufficient for use as, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, and a flexible display substrate.

  In particular, the polyimide described in Patent Document 1 is characterized by a high coefficient of linear expansion (hereinafter also referred to as CTE). When the CTE is high, the degree of expansion and contraction of the film in response to a temperature change in the TFT process or the like increases, resulting in damage to the inorganic film used in the device, and the device capability is reduced. For this reason, in order to use a polyimide resin for a substrate for forming a TFT, a substrate for forming a color filter, an alignment film, a transparent substrate for flexible display, etc., it must be colorless and transparent and have a low CTE.

  The present invention has been made in view of the above-described problems, and is a polyimide precursor that can produce a polyimide film that is colorless and transparent, has a low CTE, and is excellent in mechanical properties and thermal stability. An object is to provide a body, a resin composition containing the same, a polyimide film and a method for producing the same, and a laminate and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has obtained a polyimide having a specific structure imidized with excellent transparency, low linear expansion coefficient, mechanical properties and thermal stability. Based on this finding, the present inventors have made the present invention. That is, the present invention is as follows.

The polyimide precursor of the present invention includes a component derived from pyromellitic dianhydride (PMDA) and a component derived from 4,4′-oxydiphthalic dianhydride (ODPA) as components derived from acid dianhydride. In addition, 60 mol% or more of the total acid dianhydride-derived component is contained, and the component derived from 2,2′-bis (trifluoromethyl) benzidine (TFMB) as the component derived from diamine is 60 mol% or more of the total diamine component. wherein, prior to SL ratio of moles of component derived from PMDA and the number of moles of components derived from the ODPA (PMDA / OPDA) is 80 / 20-50 / 50 der is, component and from the ODPA from the PMDA and the number of moles of the sum of the components, the ratio of the moles of components derived from the TFMB {(PMDA + ODPA) / TFMB} , characterized in that a 100 / 99.9 to 100/95

  With this configuration, (1) PMDA and OPDA are contained in a predetermined ratio or more as components derived from acid dianhydride, (2) TFMB is contained in a predetermined ratio or more as a diamine-derived component, and (3) PMDA / OPDA is Since it satisfies the predetermined range, it is possible to produce a polyimide film which is colorless and transparent, has a low coefficient of linear expansion, and is excellent in mechanical properties and thermal stability properties.

In the polyimide precursor of the present invention, the weight average molecular weight is preferably 5000 or more. Moreover, in the polyimide precursor of this invention, it is preferable that a weight average molecular weight is 5000-1 million.

  Further, in the polyimide precursor of the present invention, the polyimide film obtained by dissolving in a solvent and spreading on the surface of the support and then imidizing at 350 ° C. in a nitrogen atmosphere has a yellowness of 12 or less and a linear expansion coefficient of 25 ppm or less. And it is preferable that breaking strength is 250 Mpa or more.

  Moreover, it is preferable that the polyimide precursor of this invention is used for manufacture of a flexible device.

  The resin composition of the present invention comprises the polyimide precursor of the present invention described above and a solvent.

  The polyimide film of the present invention is formed by developing the resin composition of the present invention described above on the surface of a support, and then imidizing the polyimide precursor by heating the support and the resin composition. It is characterized by that.

  The method for producing a polyimide film of the present invention comprises the steps of developing the resin composition of the present invention described above on the surface of a support, and imidizing the polyimide precursor by heating the support and the resin composition. Forming a polyimide film and peeling the polyimide film from the support to obtain the polyimide film.

  The laminate of the present invention comprises a support and a polyimide film, the resin composition of the present invention described above is developed on the surface of the support, and the polyimide is heated by heating the support and the resin composition. It is obtained by imidizing a precursor to form the polyimide film.

  The method for producing a laminate of the present invention comprises the steps of developing the resin composition of the present invention described above on the surface of a support, and imidizing the polyimide precursor by heating the support and the resin composition. Forming a polyimide film and obtaining a laminate composed of the support and the polyimide film.

  According to the present invention, it is possible to produce a polyimide film that is colorless and transparent, has a low coefficient of linear expansion, and is excellent in mechanical properties and thermal stability.

  Hereinafter, an embodiment of the present invention (hereinafter abbreviated as “embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  The polyimide precursor according to the present embodiment is derived from pyromellitic dianhydride (PMDA) as a component derived from acid dianhydride and from 4,4′-oxydiphthalic dianhydride (ODPA). Including 60 mol% or more of the components derived from the total acid dianhydride in total, and the component derived from 2,2′-bis (trifluoromethyl) benzidine (TFMB) as the component derived from diamine, The ratio (PMDA / OPDA) of the mole number of the PMDA-derived component and the mole number of the ODPA-derived component (PMDA / OPDA) is 80/20 to 50/50.

<Acid dianhydride-derived component>
The polyimide precursor according to the present embodiment includes, as a component derived from acid dianhydride, a component derived from pyromellitic dianhydride (hereinafter referred to as PMDA), and 4,4′-oxydiphthalic dianhydride ( (Hereinafter referred to as ODPA). The content of the component derived from PMDA and OPDA is preferably 60 mol% or more of the component derived from total acid dianhydride from the viewpoint of obtaining suitable yellowness, CTE and breaking strength of the polyimide film, and 70% or more. Is more preferably 80% or more, and may be 100%.

  As acid dianhydrides other than PMDA and OPDA, for example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), 4- (2, 5-Dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), 4,4 ′-(4,4′-isopropylidenediphenoxy) Bis (phthalic anhydride) (HBDA), 3,3′-4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA), bicyclo [2.2.2] oct-7-ene-2,3,5 , 6-tetracarboxylic dianhydride, 1R, 2S, 4S, 5R-cyclohexanetetracarboxylic dianhydride, 1S, 2S, 4R, 5R-cyclohexanetetracarboxylic dianhydride 1,2,3,4-cyclopentane tetracarboxylic acid dianhydride, and it may include one or more selected from 1,2,3,4-cyclobutane tetracarboxylic dianhydride.

<Diamine-derived component>
Moreover, the polyimide precursor which concerns on this Embodiment contains the component derived from 2,2'-bis (trifluoromethyl) benzidine (henceforth TFMB) as a diamine component. The component derived from TFMB is preferably 60 mol% or more, more preferably 70 mol% or more, from the viewpoint of obtaining suitable yellowness, CTE and breaking strength of the component polyimide film derived from all diamines. More preferably, it is at least 100% by mole.

  As components derived from diamines other than TFMB, for example, 2,2-bis [4- (4-aminophenoxy) -phenyl] propane (BAPP), 3,3′-bis (trifluoro), as long as the performance is not impaired. Methyl) -4,4′-diaminobiphenyl (3,3′-TFDB), bis [4- (4-aminophenoxy) phenyl) sulfone (BAPS), bis [4- (3-aminophenoxy) phenyl) sulfone ( BAPS-M) (, bis (3-aminophenyl) sulfone (3DDS), bis (4-aminophenyl) sulfone (4DDS), 1,3-bis (3-aminophenoxy) benzene (APB-133), 1, 4-bis (4-aminophenoxy) benzene (APB-134), 2,2′-bis [3 (3-aminophenoxy) phenyl] hexafluo Propane (3-BDAF), 2,2′-bis [4 (4-aminophenoxy) phenyl] hexafluoropropane (4-BDAF), 2,2′-bis (3-aminophenyl) hexafluoropropane (3 3′-6F), 2,2′-bis (4-aminophenyl) hexafluoropropane (4,4′-6F), oxydianiline (ODA), 1,3-bis (3-aminopropyl) 1, One or more selected from 1,3,3-tetramethyldisiloxane, 4,4′-methylenebis (4-cyclohexylamine), and 1,4-diaminocyclohexane may be included.

<PMDA / OPDA ratio>
Further, the polyimide precursor according to the present embodiment has a ratio of the number of moles of the component derived from PMDA to the number of moles of the component derived from ODPA (hereinafter referred to as PMDA / OPDA) of 80/20 to 50/50. It is. When the PMDA / OPDA is 80/20 or less, the yellowness of the polyimide film obtained by imidization at 350 ° C. in a nitrogen atmosphere can be lowered, and this is preferable from the viewpoint of improving the transparency of the hue. Moreover, the molecular weight of a polyimide precursor becomes high and it is preferable also at the point of mechanical physical property.

  When it is 50/50 or more, the CTE of the polyimide film obtained by imidization at 350 ° C. in a nitrogen atmosphere can be lowered, which is preferable. Moreover, it is also preferable from the viewpoint of obtaining a suitable breaking strength by sufficiently containing a component derived from PMDA.

<Ratio of acid dianhydride-derived component and diamine-derived component>
Furthermore, in the polyimide precursor according to the present embodiment, the ratio {(PMDA + ODPA) / TFMB} of the sum of the number of moles of the component derived from PMDA and the component derived from ODPA to the number of moles of the component derived from TFMB is 100 / It is preferable that it is 99.9-100 / 95 in the viewpoint of obtaining suitable yellowness, CTE, and breaking strength in a polyimide film.

<Resin composition>
The polyimide precursor which concerns on this Embodiment as mentioned above is used as a resin composition (varnish) which melt | dissolved this in the solvent.

  As a more preferred embodiment, the resin composition is prepared by reacting an acid dianhydride component and a diamine component by dissolving them in a solvent, for example, an organic solvent. It can be produced as a solution. Here, the conditions during the reaction are not particularly limited. For example, the reaction temperature is −20 to 100 ° C., and the reaction time is 2 to 48 hours. Moreover, it is preferable that it is inert atmosphere, such as argon and nitrogen, at the time of reaction.

  Moreover, if a solvent is a solvent which melt | dissolves a polyamic acid, it will not specifically limit. As a known reaction solvent, one kind selected from m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), acetone, and diethyl acetate The above polar solvents are useful. Of these, NMP and DMAc are preferable. In addition, a low-boiling solution such as tetrahydrofuran (THF) or chloroform, or a low-absorbing solvent such as γ-butyrolactone may be used.

  The weight average molecular weight of the polyimide precursor is preferably 5000 or more and 1000000 or less, more preferably 50000 or more and 500000 or less, and further preferably 70000 or more and 250,000 or less. When the weight average molecular weight is 5000 or more, the strength and elongation of the resin layer obtained using the resin composition is improved, and the mechanical properties are excellent. When the weight average molecular weight is 1,000,000 or less, coating can be performed without bleeding at a desired film thickness during processing such as coating. In particular, from the viewpoint of obtaining low CTE and low yellowness (YI value), the molecular weight is preferably 50,000 or more. Here, the weight average molecular weight refers to a molecular weight measured by gel permeation chromatography using polystyrene having a known number average molecular weight as a standard.

<Polyimide film>
The polyimide film according to the present embodiment develops the resin composition containing the polyimide precursor and the solvent according to the present embodiment on the surface of the support, and then heats the support and the resin composition. It is formed by imidizing a polyimide precursor. More specifically, as described above, a polyamic acid solution obtained by dissolving and reacting an acid dianhydride component and a diamine component in an organic solvent can be used.

  Here, the support is, for example, an inorganic substrate such as a glass substrate such as an alkali-free glass substrate, but is not particularly limited.

  More specifically, the polyimide precursor solution described above is spread and dried on the adhesive layer formed on the main surface of the inorganic substrate, and cured at a temperature of 300 to 500 ° C. in an inert atmosphere. A polyimide film can be formed.

  Here, examples of the developing method include known coating methods such as spin coating, slit coating, and blade coating. In addition, after the polyamic acid solution is spread on the adhesive layer, the heat treatment is performed at a temperature of 300 ° C. or lower for 1 to 300 minutes mainly for the purpose of solvent removal, and further at 300 ° C. to 550 under an inert atmosphere such as nitrogen. The polyamic acid is converted to a polyimide by heat treatment at a temperature of 1 ° C. for 1 minute to 300 minutes.

  Moreover, the thickness of the polyimide film according to the present embodiment is not particularly limited, and is preferably in the range of 10 to 50 μm, more preferably 15 to 25 μm.

<Laminated body>
The laminate according to the present embodiment includes a support and a polyimide film, the resin composition according to the present embodiment is developed on the surface of the support, and the support and the resin composition are heated to obtain a polyimide precursor. It is obtained by imidizing the body to form a polyimide film.

  This laminated body is used for manufacturing a flexible device, for example. More specifically, a semiconductor device can be formed on a polyimide film, and then a support can be peeled off to obtain a flexible device including a flexible transparent substrate made of a polyimide film.

  As described above, the polyimide precursor according to the present embodiment includes (1) PMDA and OPDA as a component derived from acid dianhydride in a predetermined ratio or more, and (2) TFMB as a component derived from diamine in a predetermined ratio. Since it is contained and (3) PMDA / OPDA is within a predetermined range, the polyimide film produced using this is colorless and transparent, has a low CTE, and further has mechanical properties. In addition, since it has excellent thermal stability, it is suitable for use on a transparent substrate of a flexible display.

  More specifically, when a flexible display is formed, a flexible substrate is formed thereon using a glass substrate as a support, and a TFT or the like is formed thereon. The process of forming the TFT on the substrate is typically performed at a wide range of temperatures of 150 to 650 ° C., but in order to actually realize the desired performance, the inorganic material is mainly used at around 350 ° C. Are used to form a TFT-IGZO (InGaZnO) oxide semiconductor or a TFT (a-Si-TFT, poly-Si-TFT).

  At this time, if the CTE of the flexible substrate is higher than that of the glass substrate, problems such as warpage or breakage of the glass substrate, peeling of the flexible substrate from the glass substrate when shrinking during normal temperature cooling after expansion in a high temperature TFT process Occurs. In general, since the thermal expansion coefficient of the glass substrate is smaller than that of the resin, the lower the linear expansion coefficient of the flexible substrate, the better. The polyimide film according to the present embodiment takes into account this point, It is preferable that an average linear expansion coefficient (CTE) measured at 100 to 300 ° C. is 25.0 ppm / ° C. or less according to the TMA method on the basis of 15 to 25 μm.

  In addition, the polyimide film according to the present embodiment has a yellowness (YI value) of 12 or less, and a transmittance of 550 nm when measured with an ultraviolet spectrophotometer on the basis of a film thickness of 15 to 25 μm. The transmittance is preferably 85% or more.

  In addition, the polyimide film according to the present embodiment has a breaking strength of 250 MPa or more on the basis of a film thickness of 15 to 25 μm from the viewpoint of improving yield by being excellent in breaking strength when handling a flexible substrate. It is preferable.

  The polyimide film according to the present embodiment satisfying the above physical properties is used as a transparent substrate for flexible displays, in particular, the use of which is limited by the yellow color of the existing polyimide film. Furthermore, for example, it can be used in fields requiring transparency, such as a protective film or a light-diffusing sheet and coating film (for example, TFT-LCD interlayer, gate insulating film, and liquid crystal alignment film) in TFT-LCD It is. When the polyimide according to this embodiment is applied as the liquid crystal alignment film, it contributes to an increase in the aperture ratio, and a TFT-LCD with a high contrast ratio can be manufactured.

  The polyimide film and laminate produced using the polyimide precursor according to the present embodiment are particularly suitable as a substrate, for example, for the production of semiconductor insulation films, TFT-LCD insulation films, electrode protection films, and flexible devices. Can be used. Here, examples of the flexible device include a flexible display, a flexible solar cell, flexible lighting, and a flexible battery.

  EXAMPLES Hereinafter, although this invention is further explained in full detail based on an Example, these are described for description and the range of this invention is not limited to the following Example.

  Various evaluations in Examples and Comparative Examples were performed as follows.

(Measurement of weight average molecular weight)
The weight average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions. As the solvent, N, N-dimethylformamide (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) was used, and 24.8 mmol / L lithium bromide monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) before the measurement. , Purity 99.5%) and 63.2 mmol / L phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) were used. A calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).
Column: Shodex KD-806M (manufactured by Showa Denko KK)
Flow rate: 1.0 mL / min Column temperature: 40 ° C
Pump: PU-2080 Plus (manufactured by JASCO)
Detector: RI-2031Plus (RI: differential refractometer, manufactured by JASCO)
UV-2075 Plus (UV-VIS: UV-Visible Absorber, manufactured by JASCO)

(Production of laminate and isolated film)
Polyamic acid is coated on a non-alkali glass substrate (thickness 0.7 mm) with a bar coater, leveled at room temperature for 5 to 10 minutes, heated in a hot air oven at 140 ° C. for 60 minutes, and further in a nitrogen atmosphere And heated at 350 ° C. for 60 minutes to prepare a laminate. The film thickness of the resin composition of the laminate was 20 μm. After curing at 350 ° C. (curing treatment), the laminate was allowed to stand at room temperature for 24 hours, and the polyimide film was peeled off from the glass to isolate the film. In the following evaluation of breaking strength, yellowness and linear expansion coefficient, this polyimide film cured at 350 ° C. was used as a sample.

(Evaluation of breaking strength)
A polyimide film having a sample length of 5 × 50 mm and a thickness of 20 μm cured at 350 ° C. was subjected to tensile measurement at a speed of 100 mm / min using a tensile tester (manufactured by A & D Co., Ltd .: RTG-1210).

(Evaluation of yellowness (YI value))
A polyimide film with a thickness of 20 μm cured at 350 ° C. was measured with a D65 light source by Nippon Denshoku Industries Co., Ltd. (Spectrophotometer: SE600).

(Evaluation of linear expansion coefficient (CTE))
The polyimide film cured at 350 ° C. was subjected to a thermomechanical analysis using a thermomechanical analyzer (TMA-50) manufactured by Shimadzu Corporation under a load of 5 g, a heating rate of 10 ° C./min, and under a nitrogen atmosphere (flow rate 20 ml / min). The elongation of the test piece in the temperature range of 50 to 450 ° C. was measured, and the CTE of the polyimide film at 100 to 300 ° C. was determined.

[Example 1]
In a 500 ml separable flask under nitrogen atmosphere, 9.00 g (28.1 mmol) of 2,2'-bis (trifluoromethyl) benzidine (TFMB) and 63.1 g of N-methyl-2-pyrrolidone (NMP) were placed. TFMB was stirred and dissolved. Then, 5.00 g (22.9 mmol) of pyromellitic dianhydride (PMDA) and 1.78 g (5.7 mmol) of 4,4′-oxydiphthalic dianhydride (ODPA) were added and stirred at 80 ° C. for 4 hours. An NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. Table 1 shows the weight average molecular weight (Mw) of the polyamic acid in the obtained varnish and the CTE, YI value and breaking strength of the film cured at 350 ° C.

[Example 2]
Example 1 except that TFMB was changed to 8.22 g (25.7 mmol), NMP 58.6 g, PMDA 4.00 g (18.3 mmol), and ODPA 2.44 g (7.9 mmol). And got a varnish. Table 1 shows the weight average molecular weight (Mw) of the polyamic acid in the obtained varnish and the film physical properties of the film cured at 350 ° C., that is, the CTE, YI value and breaking strength.

[Example 3]
Except for changing TFMB to 8.64 g (27.0 mmol), NMP 63.6 g, PMDA 3.00 g (13.8 mmol), and ODPA 4.27 g (13.8 mmol), the same as Example 1. And got a varnish. Table 1 shows the weight average molecular weight (Mw) of the polyamic acid in the obtained varnish and the CTE, YI value and breaking strength of the film cured at 350 ° C.

[Comparative Example 1]
Example 1 except that TFMB was changed to 8.79 g (27.4 mmol), NMP was changed to 60.6 g, PMDA was changed to 5.50 g (25.2 mmol), and ODPA was changed to 0.87 g (2.8 mmol). And got a varnish. Table 1 shows the weight average molecular weight (Mw) of the obtained varnish and the CTE, YI value and breaking strength of the film cured at 350 ° C.

[Comparative Example 2]
Example 1 except that TFMB was changed to 8.63 g (26.9 mmol), NMP 65.6 g, PMDA 1.80 g (8.3 mmol), and ODPA 5.97 g (19.2 mmol). And got a varnish. Table 1 shows the weight average molecular weight (Mw) of the polyamic acid in the obtained varnish and the CTE, YI value and breaking strength of the film cured at 350 ° C.

As shown in Table 1, it was confirmed that Examples 1 to 3 satisfy the following conditions simultaneously in film physical properties.
(1) CTE is 25 ppm or less (2) YI value is 12 or less (3) Breaking strength is 250 MPa or more

  On the other hand, in Comparative Example 1, the YI value was increased by increasing the PMDA component, and the breaking strength was decreased by decreasing the molecular weight of the polyimide precursor. In Comparative Example 2, the rupture strength was low due to an increase in the ODPA component, and the coefficient of thermal expansion (CTE) was high.

  From this result, when PMDA / OPDA is in the range of 80/20 to 50/50, the polyimide film is colorless and transparent, has a low coefficient of linear expansion, and has excellent mechanical and thermal stability properties. It was confirmed that can be manufactured.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously.

  The present invention can be suitably used as a substrate, for example, in the production of semiconductor insulating films, TFT-LCD insulating films, electrode protective films, and flexible displays.

Claims (10)

As a component derived from acid dianhydride, a component derived from pyromellitic dianhydride (PMDA) and a component derived from 4,4′-oxydiphthalic dianhydride (ODPA) are combined and derived from total acid dianhydride. Containing 60 mol% or more of the ingredients of
As a component derived from diamine, a component derived from 2,2′-bis (trifluoromethyl) benzidine (TFMB) is included in an amount of 60 mol% or more of the total diamine component ,
The ratio of the moles of components derived from the the number of moles of components from the previous SL PMDA ODPA (PMDA / OPDA) is Ri 80 / 20-50 / 50 der,
The ratio {(PMDA + ODPA) / TFMB} of the sum of the number of moles of the component derived from the PMDA and the component derived from the ODPA to the number of moles of the component derived from the TFMB is 100 / 99.9 to 100/95. A polyimide precursor characterized by 2. The polyimide precursor according to claim 1, having a weight average molecular weight of 5000 or more. The polyimide precursor according to claim 1 or 2, wherein the weight average molecular weight is from 5,000 to 1,000,000. After dissolving in a solvent and spreading on the surface of the support, the polyimide film obtained by imidization at 350 ° C. in a nitrogen atmosphere has a yellowness of 12 or less, a linear expansion coefficient of 25 ppm or less, and a breaking strength of 250 MPa or more. the polyimide precursor according to any one of claims 1 to 3, characterized in that. It is used for manufacture of a flexible device, The polyimide precursor in any one of Claims 1-4 characterized by the above-mentioned. A resin composition comprising the polyimide precursor according to any one of claims 1 to 5 and a solvent. A polyimide film formed by spreading the resin composition according to claim 6 on a surface of a support, and then imidizing the polyimide precursor by heating the support and the resin composition. . Spreading the resin composition according to claim 6 on the surface of the support;
Heating the support and the resin composition to imidize the polyimide precursor to form a polyimide film;
Peeling the polyimide film from the support to obtain the polyimide film;
The manufacturing method of the polyimide film characterized by comprising. A support and a polyimide film are provided, the resin composition according to claim 6 is spread on the surface of the support, the support and the resin composition are heated to imidize the polyimide precursor, and the polyimide. A laminate obtained by forming a film. Developing the resin composition according to claim 6 on the surface of the support;
Heating the support and the resin composition to imidize the polyimide precursor to form a polyimide film, and obtaining a laminate composed of the support and the polyimide film; and
The manufacturing method of the laminated body characterized by comprising.