JP2018187914A - Laminate, method for producing display device and flexible display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate that can prevent a display device from turning yellow due to thermal hysteresis in the production process.SOLUTION: A laminate has a support substrate, and a display device substrate disposed on the support substrate and containing a polyimide having a predetermined structure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminate used for manufacturing a display device, and relates to a laminate having a polyimide film.

  Polyimide is widely applied to insulating materials for electronic components because it has the top performance among organic materials such as heat resistance, dimensional stability, and insulation characteristics. Chip coating films and flexible printed wiring in semiconductor devices It has been actively used as a base material for plates.

  Conventionally, as a method for forming a polyimide film, a method in which a polyamic acid varnish is applied on a substrate and subjected to an imidization reaction by heating or the like is generally used. Moreover, in the polyimide which has a structure soluble in a solvent, the method of apply | coating a polyimide varnish directly on a base material is used.

  In recent years, with the development of display devices, the demand for flat panel display devices such as liquid crystal display devices and organic EL display devices has increased. Recently, in addition to televisions and personal computers, multifunctional terminals such as smartphones and tablet terminals are widely used, and the market for flat panel display devices is increasing. In such a situation, research on each member constituting the flat panel display device has been actively conducted.

  For example, due to demands for thinning, lightening, and flexibility of display devices, attempts have been made to change the glass currently used as a base material to a resin film. A flexible display device using a member in which functional layers are laminated has been proposed (for example, Patent Document 1). Since the flexible display device can be freely deformed, for example, a rollable mobile display device can be realized, and there is an advantage that a display device more suitable for mobile can be obtained. Moreover, a flexible display apparatus can be manufactured by a continuous process using a long film, for example, and also has the advantage that it is excellent in productivity.

Polyimide is one of materials that are highly heat resistant, lightweight, strong, and has been studied as a material that can replace glass early on, but there are still problems to be studied.
One of them is transparency. There is a problem that polyimide is yellowed by oxidation when heated in the atmosphere. Therefore, heating in an inert atmosphere is recommended to maintain transparency. On the other hand, a polyimide varnish containing a polyimide having a structure soluble in a solvent is a solution of a polyimide in a state where the thermosetting treatment is completed, so when forming a polyimide film using a polyimide varnish, Although there is little concern about yellowing due to heating in the atmosphere, the solvent resistance is reduced, so it is not suitable for forming a functional layer on a polyimide film by a coating method. In addition, the polyimide film can be used for a display device that requires a process involving heating because of its high heat resistance, but when a display device is manufactured using the polyimide film, heat is generated in the manufacturing process of the display device. There is a problem that yellowing occurs due to the history.

JP 2011-027822 A

  The present invention has been made in view of the above circumstances, and provides a laminated body that is used for manufacturing a display device and that can suppress yellowing due to a thermal history in a manufacturing process of the display device. The main purpose is to do.

  In order to achieve the above object, the present invention includes a supporting base material, an aromatic ring that is disposed on the supporting base material, and represented by the following general formula (1) and the following general formula (3). And a substrate for a display device containing a polyimide having at least one structure selected from the group consisting of the following structures.

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.)

  According to the present invention, since the base material for display device contains polyimide having a predetermined structure, yellowing due to oxidation in the heating process can be suppressed, so the display device using the laminate of the present invention. In the case of manufacturing, it is possible to suppress yellowing due to the heat history in the manufacturing process of the display device.

  Moreover, in this invention, it is preferable that the thickness of the said base material for display apparatuses exists in the range of 3 micrometers or more and 12 micrometers or less. When the thickness of the base material for a display device is in the above range, desired flexibility can be realized.

  Moreover, the laminated body of this invention may have the adhesion layer arrange | positioned between the said support base material and the said base material for display apparatuses.

  Furthermore, the laminated body of this invention may have the functional layer arrange | positioned on the said base material for display apparatuses. Even in the case of performing the heating step when forming the functional layer, yellowing due to the thermal history of the display device substrate can be suppressed as in the above case.

In the present invention, the polyimide has a structure represented by the general formula (3). In the general formula (3), R ⁵ is 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue. R ⁶ represents a 2,2′-bis (trifluoromethyl) benzidine residue, and the laminate of the present invention includes, as the functional layer, in order from the display device substrate side, the stress relaxation layer, It is preferable to have two or more barrier layers. Such a polyimide is preferable in terms of high transparency and a low yellowness YI value. Further, the barrier property can be improved by the two or more barrier layers and the stress relaxation layer.

In the present invention, the polyimide has a structure represented by the general formula (3). In the general formula (3), R ⁵ is 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue. R ⁶ represents a 4,4′-diaminodiphenylsulfone residue, and the laminate of the present invention has, as the functional layer, a stress relaxation layer and two or more layers in order from the substrate side for the display device. And may have a barrier layer. Such a polyimide is preferable in terms of high transparency. Further, the barrier property can be improved by the two or more barrier layers and the stress relaxation layer.

In the present invention, the polyimide has a structure represented by the general formula (3). In the general formula (3), R ⁵ is 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue. R ⁶ represents a paraphenylenediamine residue, and the laminate of the present invention comprises, as the functional layer, a stress relaxation layer and two or more barrier layers in order from the substrate side for the display device. You may have. Such a polyimide is preferable in terms of high transparency. Further, the barrier property can be improved by the two or more barrier layers and the stress relaxation layer.

In the present invention, the polyimide has a structure represented by the general formula (1). In the general formula (1), R ¹ is 2,3 ′, 3,4′-biphenyltetracarboxylic acid. Represents a residue, R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue, and the laminate of the present invention serves as the functional layer in order from the substrate side for the display device in the order of the stress relaxation layer. And two or more barrier layers. Such a polyimide is preferable in terms of high transparency. Further, the barrier property can be improved by the two or more barrier layers and the stress relaxation layer.

In the present invention, the polyimide has a first structure represented by the general formula (1) and a second structure represented by the general formula (1). In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. In the general formula (1), R ¹ represents a pyromellitic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. Preferably, the content of the first structure is 90 mol% or more based on the total of the structures represented by the general formula (1) and the general formula (3), The content of the structure of 2 is represented by the general formula (1) and the general formula (3). 10 mol% or less may be sufficient with respect to the sum total of the structure to be made. As described above, the first structure is preferable in that the transparency is high and the yellowness YI value is low. Therefore, when the content of the first structure and the second structure is in the above range, transparency can be improved and yellowing due to thermal history can be suppressed.

In the present invention, the polyimide has a first structure represented by the general formula (1) and a second structure represented by the general formula (1). In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. In the general formula (1), R ¹ represents a pyromellitic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. Preferably, the content of the first structure is 50 mol% or more and 95 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). And the content of the second structure is the above general formula (1) and the above general 5 mol% or more and 50 mol% or less may be sufficient with respect to the sum total of the structure represented by Formula (3). As described above, the first structure is preferable in that the transparency is high and the yellowness YI value is low. The second structure is suitable for improving rigidity and is preferable in that the linear thermal expansion coefficient is low. Therefore, when the content of the first structure and the second structure is in the above range, transparency can be improved, yellowing due to thermal history can be suppressed, and linear thermal expansion can be reduced. .

In the present invention, the polyimide has a first structure represented by the general formula (1) and a third structure represented by the general formula (1). In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. In the general formula (1), R ¹ represents a 3,3 ′, 4,4′-biphenyltetracarboxylic acid residue, and R ² represents 2,2′-. It is also preferable that the structure represents a bis (trifluoromethyl) benzidine residue, and the content of the first structure is based on the total of the structures represented by the general formula (1) and the general formula (3). And the content of the third structure is not less than 90 mol% and the general formula (1 And the total of the structure represented by the general formula (3), may be 10 mol% or less. As described above, the first structure is preferable in that the transparency is high and the yellowness YI value is low. Therefore, when the content of the first structure and the third structure is in the above range, transparency can be improved and yellowing due to thermal history can be suppressed.

In the present invention, the polyimide has a first structure represented by the general formula (1) and a third structure represented by the general formula (1). In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. In the general formula (1), R ¹ represents a 3,3 ′, 4,4′-biphenyltetracarboxylic acid residue, and R ² represents 2,2′-. It is also preferable that the structure represents a bis (trifluoromethyl) benzidine residue, and the content of the first structure is based on the total of the structures represented by the general formula (1) and the general formula (3). And the content of the third structure is 30 mol or more and 95 mol% or less. The total of the structure represented by the general formula (1) and the general formula (3), may be 70 mol% or less 5 mole or more. As described above, the first structure is preferable in that the transparency is high and the yellowness YI value is low. The third structure is suitable for improving the rigidity and is preferable in terms of a low linear thermal expansion coefficient. Therefore, when the content of the first structure and the third structure is in the above range, transparency can be improved, yellowing due to thermal history can be suppressed, and linear thermal expansion can be reduced. .

  Moreover, this invention arrange | positions on the surface on the opposite side or the said functional layer of the said functional layer of the said base material for display apparatuses, the functional layer formed on the said base material for display apparatuses, and the said base material for display apparatuses A display device having a display panel, comprising a structure including an aromatic ring on a support substrate and represented by the general formula (1) and the general formula (3). A preparation step of preparing the display device substrate containing polyimide having at least one structure selected from the group, and a functional layer formation for forming the functional layer on the display device substrate after the preparation step There is provided a method for manufacturing a display device comprising a step and a peeling step of peeling the support substrate after the functional layer forming step.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to suppress yellowing by the heat history in the manufacturing process of a display apparatus because the base material for display apparatuses contains the polyimide which has a predetermined structure.

  Furthermore, the present invention provides a display device comprising a polyimide having an aromatic ring and having at least one structure selected from the group consisting of the structures represented by the general formula (1) and the general formula (3). Substrate, a functional layer disposed on the display device substrate, and a display panel disposed on the surface opposite to the functional layer of the display device substrate or on the functional layer A flexible display device is provided.

  According to the present invention, since the base material for display device contains polyimide having a predetermined structure, yellowing due to the heat history in the manufacturing process of the flexible display device can be suppressed, so that good display quality is obtained. be able to.

  The present invention has an effect that yellowing due to a heat history in a manufacturing process of a display device can be suppressed by including a polyimide having a predetermined structure in the display device base material.

It is a schematic sectional drawing which shows an example of the laminated body of this invention. It is a schematic sectional drawing which shows the other example of the laminated body of this invention. It is a schematic sectional drawing which shows the other example of the laminated body of this invention. It is a schematic sectional drawing which shows the other example of the laminated body of this invention. It is a schematic sectional drawing which shows the other example of the laminated body of this invention. It is a schematic process drawing which shows an example of the manufacturing method of the display apparatus of this invention. It is a schematic process drawing which shows the other example of the manufacturing method of the display apparatus of this invention. It is a schematic sectional drawing which shows an example of the flexible display apparatus of this invention.

  Hereinafter, the laminate, the manufacturing method of the display device, and the flexible display device of the present invention will be described.

I. Laminated body The laminated body of this invention is arrange | positioned on the said support base material and the said support base material, contains an aromatic ring, and is from the structure represented by following General formula (1) and following General formula (3). It is a member characterized by having a display device substrate containing polyimide having at least one structure selected from the group consisting of:

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.)

  The laminated body of this invention can be used for manufacture of the display apparatus which requires the process with a heating using the high heat resistance of the base material for display apparatuses which is a polyimide film. Since the polyimide having the above structure has low reactivity with oxygen, it is presumed that the chemical structure of the polyimide is difficult to change. In addition, the polyimide having the above structure includes at least one selected from the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a linking group that cleaves the electronic conjugation between aromatic rings. Since it can be contained, the movement of electric charges in the polyimide skeleton can be inhibited, and a decrease in transparency can be suppressed. Specifically, when the polyimide contains (i) a fluorine atom, the electronic state in the polyimide skeleton can be made difficult to transfer charges, and the transparency is improved. Further, when the polyimide contains (ii) an aliphatic ring, the transfer of charges in the skeleton can be inhibited by breaking the π-electron conjugation in the polyimide skeleton, and the transparency is improved. Furthermore, when the polyimide contains a linking group that cleaves the electron conjugation between aromatic rings (iii), it is possible to inhibit the movement of charges in the skeleton by breaking the π electron conjugation in the polyimide skeleton, Transparency is improved. Therefore, even when a heating process in the atmosphere is performed, for example, in the case of manufacturing a display device using the laminate of the present invention, a process involving heating in an air atmosphere when forming a functional layer on a substrate for a display device. Even if it goes, it is possible to suppress changes in optical characteristics, in particular, the yellowness YI value and the total light transmittance. In addition, when manufacturing a display device using the laminate of the present invention, it is not necessary to carry out a process involving heating in an inert atmosphere in order to maintain transparency. There is an advantage that can be suppressed.

Furthermore, as described in the first aspect described later, when the display device substrate is disposed on the support substrate, a polyimide precursor solution containing polyamic acid is applied onto the support substrate and temporarily dried. In addition, after forming the polyimide precursor coating film, the polyimide precursor coating film is imidized by heat treatment to form a polyimide film, even if this heat treatment is performed in an air atmosphere, as in the above case, Changes in optical characteristics, particularly yellowness YI value and total light transmittance can be suppressed. Similarly, since it is not necessary to perform the heat treatment in an inert atmosphere in order to maintain transparency, it is possible to suppress equipment costs and costs for atmospheric control.
Moreover, when forming a polyimide film using a polyimide precursor solution, after raising temperature to predetermined | prescribed temperature, in order to fully advance imidation, it is common to hold | maintain at that temperature for a fixed time. On the other hand, in the polyimide having the above structure, imidization sufficiently proceeds by raising the temperature to the glass transition temperature or higher, so that the heat treatment holding time can be shortened and the production cost can be reduced.

Here, polyimide containing an aromatic ring not only has excellent heat resistance, but also has a linear thermal expansion coefficient that is as small as that of metal, ceramics, or glass due to its rigid skeleton. However, as the inventors proceed with research, polyimides with high rigidity and low linear thermal expansion have a rigid chemical structure. As a result, polyimide films with high rigidity and low linear thermal expansion have large optical properties. It was confirmed that mechanical distortion (birefringence) was generated. On the other hand, the polyimide film with small birefringence has low rigidity and large linear thermal expansion, and it has been found that the linear thermal expansion and birefringence of the polyimide film are in a trade-off relationship. A polyimide film having a rigid skeleton and high orientation has a high rigidity and a small linear thermal expansion, but the birefringence increases due to the orientation of the rigid chemical structure, while the polyimide film having a skeleton with a low linearity. Since the film has a low linearity chemical structure randomly arranged, the polarization component is present isotropically, so the birefringence is small, but the rigidity is low and the linear thermal expansion is presumed.
On the other hand, according to the present invention, a polyimide containing an aromatic ring and having a specific rigid chemical structure is selected. Further, the chemical structure of the tetracarboxylic acid component and the diamine component, and the predetermined chemical structure are selected. By appropriately selecting the introduction ratio of the tetracarboxylic acid component and the diamine component, the linear thermal expansion coefficient of the substrate for a display device, which is a polyimide film, can be lowered and the birefringence can be reduced.

  Thus, a substrate for a display device having high heat resistance, transparency, low linear thermal expansion, and reduced optical distortion is suitable for a display device, and the laminate of the present invention is preferably used for production of a display device. be able to.

  The laminated body of this invention can be divided roughly into two aspects. Hereinafter, the laminate of the present invention will be described separately for each embodiment.

A. 1st aspect The laminated body of this aspect is a structure which is arrange | positioned on the said support base material and the said support base material, contains an aromatic ring, and is represented by the said General formula (1) and the said General formula (3). And a substrate for a display device containing a polyimide having at least one structure selected from the group consisting of:

Hereinafter, the laminated body of this aspect is demonstrated, referring a figure.
FIG. 1 is a schematic cross-sectional view showing an example of the laminate of this embodiment. As shown in FIG. 1, the laminated body 1 has the support base material 2 and the base material 3 for display apparatuses which contains the polyimide which is arrange | positioned on the support base material 2 and has a predetermined structure.

  In this embodiment, the display device substrate is disposed directly on the support substrate. For example, a polyimide precursor solution containing a polyamic acid is applied onto the support substrate and temporarily dried to obtain a polyimide precursor. After forming the coating film, the polyimide precursor coating film is imidized by heat treatment to form a polyimide film, whereby a display device substrate can be formed directly on the support substrate.

  According to this aspect, as described above, even when the heat treatment for producing the substrate for a display device, which is a polyimide film, is performed in an air atmosphere, the optical characteristics, in particular, the yellowness YI value and the change in the total light transmittance are changed. Can be suppressed. In addition, since it is not necessary to perform this heat treatment in an inert atmosphere in order to maintain transparency, it is possible to suppress equipment costs and costs for atmospheric control. Further, the heat treatment holding time can be shortened, and the production cost can be reduced.

  Moreover, according to this aspect, since the base material for display apparatuses can be formed by apply | coating a polyimide precursor solution on a support base material, it can aim at the thin film of the base material for display apparatuses, and flexibility Can be improved. Therefore, the laminated body of this aspect is suitable for manufacturing a flexible display device.

  Hereinafter, each structure in the laminated body of this aspect is demonstrated.

1. Base material for display device The base material for display device in this aspect is a member which contains the polyimide which is arrange | positioned on a support base material and has a predetermined structure.

  Hereinafter, each structure in the base material for display apparatuses is demonstrated.

(1) Polyimide The polyimide used in the present invention is a polyimide containing an aromatic ring, and contains an aromatic ring in at least one of a tetracarboxylic acid component and a diamine component. Furthermore, the polyimide used in the present invention has at least one structure selected from the group consisting of structures represented by the following general formula (1) and the following general formula (3).

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.)

Here, the tetracarboxylic acid residue means a residue obtained by removing four carboxyl groups from tetracarboxylic acid, and represents the same structure as a residue obtained by removing acid dianhydride structure from tetracarboxylic dianhydride. .
Moreover, a diamine residue means the residue remove | excluding two amino groups from diamine.

In the general formula (1), R ¹ is a tetracarboxylic acid residue, and can be a residue obtained by removing an acid dianhydride structure from a tetracarboxylic dianhydride as described later.

Specific examples of the tetracarboxylic dianhydride include cyclohexanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, dicyclohexane-3,4,3 ′, 4′-tetracarboxylic dianhydride, pyro Merit acid dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2 -Bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1 -Bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2- Bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1 , 3,3,3-hexafluoropropane dianhydride, 1,3-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 1,4-bis [(3,4-dicarboxy) benzoyl Benzene dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, 2,2-bis {4- [3- (1,2- Dicarboxy) phenoxy] phenyl} propane Water, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride 4,4′-bis [4- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, 4,4′-bis [3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4 -[4- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [ 4- (1,2-dicarboxy ) Phenoxy] phenyl} sulfide dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, 3,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, 3,3 ′-(hexafluoroisopropylidene) diphthalic anhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1, 4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4, 9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid Anhydride, and the like.
These may be used alone or in combination of two or more.

As R ¹ in the general formula (1), from the viewpoint of improving transparency, (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a linking group that cleaves the electron conjugation between aromatic rings. It is preferable to include at least one selected from the group consisting of: The polyimide containing an aromatic ring tends to have a reduced transmittance depending on the absorption wavelength of the aromatic ring. However, when R ¹ contains at least one of the above (i) to (iii), the transparency is improved. Because it can. Since the reason why the transparency is improved by including at least one of the above (i) to (iii) is described above, description thereof is omitted here.
Examples of the linking group that cleaves the electron conjugation between aromatic rings (iii) include, for example, an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an amide bond, a sulfonyl bond, a sulfinyl bond, and fluorine substitution. And a divalent linking group such as an alkylene group which may be used.

R ¹ in the general formula (1) is, among others, 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, 3,3 ′, 4,4′-biphenyltetra, from the viewpoint of improving transparency. Carboxylic acid residue, pyromellitic acid residue, 2,3 ′, 3,4′-biphenyltetracarboxylic acid residue, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid residue, 3,3 ′, Including at least one selected from the group consisting of 4,4′-diphenylsulfonetetracarboxylic acid residue, 4,4′-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue Further, 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, 4,4′-oxydiphthalic acid residue, and 3,3 ′, 4,4′-diphenylsulfone tetracar Preferably contains at least one selected from the group consisting of phosphate residues.
In R ¹ , these suitable residues are preferably contained in a total amount of 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

As described later, since the polyimide preferably contains a fluorine atom from the viewpoint of improving transparency, the tetracarboxylic acid residue preferably contains a fluorine atom. Therefore, it is particularly preferable that R ¹ includes a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue.
In R ¹ , this suitable residue is preferably contained in an amount of 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

  Further, at least selected from the group consisting of 3,3 ′, 4,4′-biphenyltetracarboxylic acid residue, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid residue, and pyromellitic acid residue A group of tetracarboxylic acid residues (group A) suitable for improving rigidity such as one kind, 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, 2,3 ′, 3,4 '-Biphenyltetracarboxylic acid residue, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid residue, 4,4'-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid It is also preferable to use a mixture of a tetracarboxylic acid residue group (group B) suitable for improving transparency, such as at least one selected from the group consisting of residues.

  In this case, the content ratio of the tetracarboxylic acid residue group (group A) suitable for improving rigidity and the tetracarboxylic acid residue group (group B) suitable for improving transparency is transparent. The tetracarboxylic acid residue group (group A) suitable for improving the rigidity is 0.05 mol or more per 1 mol of the tetracarboxylic acid residue group (group B) suitable for improving the property. It may be less than or equal to 1 mol, more preferably between 0.1 and 5 mol, and particularly between 0.3 and 4 mol.

  In the above case, as described later, the polyimide preferably contains a fluorine atom from the viewpoint of improving the transparency, and therefore a tetracarboxylic acid residue group (group B) suitable for improving the transparency. ) Preferably contains a fluorine atom. Therefore, it is particularly preferable that the tetracarboxylic acid residue group (group B) suitable for improving transparency contains 4,4 '-(hexafluoroisopropylidene) diphthalic acid residue.

R ² in the general formula (1) is, among others, 4,4′-diaminodiphenylsulfone residue, 3,4′-diaminodiphenylsulfone residue, and the above general formula (2) from the viewpoint of improving transparency. It is preferably at least one divalent group selected from the group consisting of divalent groups represented by the following formula: 4,4′-diaminodiphenylsulfone residue, 3,4′-diaminodiphenylsulfone The residue and R ³ and R ⁴ are preferably at least one divalent group selected from the group consisting of a divalent group represented by the above general formula (2), which is a perfluoroalkyl group. .

As described later, since the polyimide preferably contains a fluorine atom from the viewpoint of improving transparency, the diamine residue preferably contains a fluorine atom. Therefore, it is more preferable that R ² includes a divalent group represented by the above general formula (2) in which R ³ and R ⁴ are perfluoroalkyl groups. Furthermore, in the general formula (2), when R ³ and R ⁴ are perfluoroalkyl groups, the perfluoroalkyl group is preferably a trifluoromethyl group. That is, R ² particularly preferably includes a 2,2′-bis (trifluoromethyl) benzidine residue.

As a preferable structure represented by the general formula (1), for example, in the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents 2,2 A structure representing a '-bis (trifluoromethyl) benzidine residue; R ¹ represents a 4,4'-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 4,4'-diaminodiphenylsulfone residue. And a structure in which R ¹ represents a 2,3 ′, 3,4′-biphenyltetracarboxylic acid residue and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. These polyimides are preferably used from the viewpoint of improving transparency.

Particularly, in the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue. Is preferred. In this structure, both the tetracarboxylic acid residue and the diamine residue contain a fluorine atom. Such a polyimide is preferable because of its high transparency and low yellowness YI value.

Further, in the structure represented by the general formula (1), as described above, a tetracarboxylic acid residue group (group A) suitable for improving rigidity and suitable for improving transparency. It is also preferable to use a mixture of a tetracarboxylic acid residue group (group B). Specifically, in the general formula (1), the polyimide has a structure in which R ¹ is a tetracarboxylic acid residue group (group A) suitable for improving rigidity, and the general formula (1). , R ¹ is a tetracarboxylic acid residue group (group B) suitable for improving transparency.

In the above case, polyimide, a first structure represented by the general formula (1), in the general formula (1), R ¹ is 4,4 '- represents a (hexafluoroisopropylidene) diphthalic acid residue , R ² has a structure representing a 2,2′-bis (trifluoromethyl) benzidine residue, and as a second structure represented by the general formula (1), in the general formula (1), R ¹ Preferably represents a pyromellitic acid residue and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue.
In this case, the content of the first structure is 90 mol% or more based on the total of the structures represented by the general formula (1) and the general formula (3). The content may be 10 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). As described above, the first structure is preferable from the viewpoint of high transparency and low yellowness YI value. Therefore, when the content of the first structure and the second structure is in the above range, transparency can be improved and yellowing due to thermal history can be suppressed.
In this case, the content of the first structure is 50 mol% or more and 95 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). The content of the second structure may be 5 mol% or more and 50 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). As described above, the first structure is preferable from the viewpoint of high transparency and low yellowness YI value. The second structure is suitable for improving rigidity and is preferable in that the linear thermal expansion coefficient is low. Therefore, when the content of the first structure and the second structure is in the above range, transparency can be improved, yellowing due to thermal history can be suppressed, and linear thermal expansion can be reduced. .

In the above case, the polyimide has, as the first structure represented by the general formula (1), in the general formula (1), R ¹ is 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue. And R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue, and the third structure represented by the general formula (1) is represented by the general formula (1): It is also preferable that R ¹ represents a 3,3 ′, 4,4′-biphenyltetracarboxylic acid residue and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue.
In this case, the content of the first structure is 90 mol% or more based on the total of the structures represented by the general formula (1) and the general formula (3). The content may be 10 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). As described above, the first structure is preferable from the viewpoint of high transparency and low yellowness YI value. Therefore, when the content of the first structure and the third structure is in the above range, transparency can be improved and yellowing due to thermal history can be suppressed.
In this case, the content of the first structure is 30 mol% or more and 95 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). The content of the third structure may be 5 mol% or more and 70 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). As described above, the first structure is preferable from the viewpoint of high transparency and low yellowness YI value. The third structure is suitable for improving the rigidity and is preferable in terms of a low linear thermal expansion coefficient. Therefore, when the content of the first structure and the third structure is in the above range, transparency can be improved, yellowing due to thermal history can be suppressed, and linear thermal expansion can be reduced. .

In the general formula (3), R ⁶ is a diamine residue, which can be a residue obtained by removing two amino groups from a diamine as described later.

  Specific examples of the diamine include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3 ′. -Diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzanilide, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3 , 4'-di Minodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2, 2-di (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3,3,3- Hexafluoropropane, 2- (3-aminophenyl) -2- (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-di (3-aminophenyl)- 1-phenylethane, 1,1-di (4-aminophenyl) -1-phenylethane, 1- (3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane, 1,3-bis (3-Aminophenoxy) benze 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminobenzoyl) ) Benzene, 1,3-bis (4-aminobenzoyl) benzene, 1,4-bis (3-aminobenzoyl) benzene, 1,4-bis (4-aminobenzoyl) benzene, 1,3-bis (3- Amino-α, α-dimethylbenzyl) benzene, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-amino-α, α-dimethylbenzyl) benzene, 1 , 4-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,3-bis (4-amino-) , Α-ditrifluoromethylbenzyl) benzene, 1,4-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (4-amino-α, α-ditrifluoromethylbenzyl) Benzene, 2,6-bis (3-aminophenoxy) benzonitrile, 2,6-bis (3-aminophenoxy) pyridine, N, N′-bis (4-aminophenyl) terephthalamide, 9,9-bis ( 4-aminophenyl) fluorene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4 ′ -Diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-bi (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, Bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide,

Bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-amino) Phenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3 3,3-hexafluoropropane, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (4-aminophenoxy) benzoyl] ben 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-amino Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (3-aminophenoxy) -Α, α-dimethylbenzyl] benzene, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 4,4'-bis [4- (4-aminophenoxy) benzoyl ] Diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzen) ) Phenoxy] diphenylsulfone, 4,4′-bis [4- (4-aminophenoxy) phenoxy] diphenylsulfone, 3,3′-diamino-4,4′-diphenoxybenzophenone, 3,3′-diamino-4 , 4′-Dibiphenoxybenzophenone, 3,3′-diamino-4-phenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 6,6′-bis (3-aminophenoxy) -3,3 3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, , 3-bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-aminobutyl) tetramethyldisiloxane, α, ω-bis ( -Aminopropyl) polydimethylsiloxane, α, ω-bis (3-aminobutyl) polydimethylsiloxane, bis (aminomethyl) ether, bis (2-aminoethyl) ether, bis (3-aminopropyl) ether, bis ( 2-aminomethoxy) ethyl] ether, bis [2- (2-aminoethoxy) ethyl] ether, bis [2- (3-aminoprotoxy) ethyl] ether,

trans-cyclohexanediamine, trans-1,4-bismethylenecyclohexanediamine, 2,6-bis (aminomethyl) bicyclo [2,2,1] heptane, 2,5-bis (aminomethyl) bicyclo [2,2, 1] and heptane. In addition, a diamine obtained by substituting some or all of the hydrogen atoms on the aromatic ring of the diamine with a substituent selected from a fluoro group, a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group is also used. Can do.
These may be used alone or in combination of two or more.

As R ⁶ in the general formula (3), from the viewpoint of improving transparency, (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a linking group that cleaves the electron conjugation between aromatic rings. It is preferable to include at least one selected from the group consisting of: The polyimide containing an aromatic ring has a tendency that the transmittance decreases depending on the absorption wavelength of the aromatic ring. However, when R ⁶ contains at least one of the above (i) to (iii), the transparency is improved. Because it can. In addition, about the reason that transparency improves by including at least one of the above (i) to (iii), and the specific example of the linking group that cleaves the electron conjugation between the aromatic rings (iii) above, Since it was mentioned above, explanation here is omitted.

R ⁶ in the general formula (3) is, among others, 2,2′-bis (trifluoromethyl) benzidine residue, bis [4- (4-aminophenoxy) phenyl] sulfone from the viewpoint of improving transparency. Residue, 4,4′-diaminodiphenylsulfone residue, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane residue, bis [4- (3-aminophenoxy) phenyl] sulfone residue Group, 4,4′-diamino-2,2′-bis (trifluoromethyl) diphenyl ether residue, 1,4-bis [4-amino-2- (trifluoromethyl) phenoxy] benzene residue, 2,2 -Bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane residue, 4,4′-diamino-2- (trifluoromethyl) diphen The group consisting of a ruether residue, 4,4′-diaminobenzanilide residue, N, N′-bis (4-aminophenyl) terephthalamide residue, and 9,9-bis (4-aminophenyl) fluorene residue It preferably contains at least one divalent group selected from: 2,2′-bis (trifluoromethyl) benzidine residue, bis [4- (4-aminophenoxy) phenyl] sulfone residue, And at least one divalent group selected from the group consisting of 4,4′-diaminodiphenylsulfone residues.
In R ⁶ , these suitable residues are preferably contained in a total amount of 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

In general formula (3), R ⁶ may contain a paraphenylenediamine residue.

As described later, since the polyimide preferably contains a fluorine atom from the viewpoint of improving transparency, the diamine residue preferably contains a fluorine atom. Therefore, R ⁶ particularly preferably contains a 2,2′-bis (trifluoromethyl) benzidine residue.
In R ⁶ , these suitable residues are preferably contained in a total amount of 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

  In addition, bis [4- (4-aminophenoxy) phenyl] sulfone residue, 4,4′-diaminobenzanilide residue, N, N′-bis (4-aminophenyl) terephthalamide residue, paraphenylenediamine residue A group of diamine residues suitable for improving rigidity (group C), such as at least one selected from the group consisting of a group, a metaphenylenediamine residue, and a 4,4′-diaminodiphenylmethane residue; 2,2′-bis (trifluoromethyl) benzidine residue, 4,4′-diaminodiphenylsulfone residue, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane residue, bis [ 4- (3-aminophenoxy) phenyl] sulfone residue, 4,4′-diamino-2,2′-bis (trifluoromethyl) diphenylate Residue, 1,4-bis [4-amino-2- (trifluoromethyl) phenoxy] benzene residue, 2,2-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoro Such as at least one selected from the group consisting of a propane residue, a 4,4′-diamino-2- (trifluoromethyl) diphenyl ether residue, and a 9,9-bis (4-aminophenyl) fluorene residue It is also preferable to mix and use a diamine residue group (group D) suitable for improving transparency.

  In this case, the content ratio of the diamine residue group (group C) suitable for improving rigidity and the diamine residue group (group D) suitable for improving transparency improves transparency. The diamine residue group (group C) suitable for improving rigidity is preferably 0.05 mol or more and 9 mol or less with respect to 1 mol of the diamine residue group (group D) suitable for Among these, it is preferably 0.1 mol or more and 5 mol or less, and particularly preferably 0.3 mol or more and 4 mol or less.

In general formula (3), R ⁵ preferably contains a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue from the viewpoint of improving transparency.
In R ⁵ , a suitable residue is preferably contained in an amount of 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

As a preferable structure represented by the general formula (3), for example, in the general formula (3), R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ represents 2,2 A structure representing a '-bis (trifluoromethyl) benzidine residue; R ⁵ represents a 4,4'-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ represents a 4,4'-diaminodiphenylsulfone residue. And a structure in which R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue and R ⁶ represents a paraphenylenediamine residue. These polyimides are preferably used from the viewpoint of improving transparency.

In particular, in the general formula (3), R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ represents a 2,2′-bis (trifluoromethyl) benzidine residue. Is preferred. In this structure, both the tetracarboxylic acid residue and the diamine residue contain a fluorine atom. Such a polyimide is preferable because of its high transparency and low yellowness YI value.

In the structures represented by the general formula (1) and the general formula (3), n and n ′ each independently represent the number of repeating units and are 1 or more.
The number of repeating units n in the polyimide may be appropriately selected depending on the structure so that the display device shows a preferable glass transition temperature described later, and is not particularly limited.
The average number of repeating units is usually from 10 to 2000, and preferably from 15 to 1000.

  Here, the substrate for a display device includes an aromatic ring and has at least one structure selected from the group consisting of the structures represented by the general formula (1) and the general formula (3). It can be confirmed by analyzing the decomposition product of polyimide using a gas chromatograph mass spectrometer. For example, the structure of the polyimide can be confirmed by decomposing the sample with an alkaline aqueous solution or supercritical methanol, and performing a qualitative analysis of the obtained decomposition product using a gas chromatograph mass spectrometer or the like.

Specifically, the following analysis methods can be used. That is, pretreatment is performed as follows, and the polyimide film (base material for display device) is decomposed with supercritical methanol to obtain a polyimide decomposition product, and the entire qualitative analysis is performed on the polyimide decomposition product using GC-MS. I do.
<Pretreatment>
(I) The base material for a display device is shaved with a scalpel, and a few μg (about 1/10 in internal volume) of the shaved base material for a display device is put into a glass tube (Glass capsule b: manufactured by Frontier LAB).
(Ii) 15 μL of methanol is injected into the glass tube containing the sample with a microsyringe.
(Iii) A glass tube containing a base material sample for display device and methanol is sealed with a burner.
(Iv) Place the sealed glass tube in an electric furnace at 280 ° C. and leave it for 10 hours.
(V) Remove the glass tube from the electric furnace and open it.
(Vi) Collect all the liquid in the glass tube with a micro syringe and inject it into the cup for GCMS.
<Gas chromatograph mass spectrometry>
Equipment used: GCMS: GCMS2020 (manufactured by Shimadzu Corporation)
Electric furnace: W shot pyrolyzer (manufactured by FLONTIER LAB)
Electric furnace temperature: 320 ° C
Inlet temperature: 320 ° C
Oven conditions: Hold at 50 ° C. for 5 minutes −Raise at 10 ° C./minute −Hold at 320 ° C. for 15 minutes
Ion source temperature: 260 ° C
Measurement mass range: m / z: 40-650
Column: UA (Ultra Alloy) -5 Length: 30 m Inner diameter: 0.25 mm Film thickness: 0.25 μm

The polyimide used in the present invention includes at least one structure selected from the group consisting of the structure represented by the general formula (1) and the general formula (3), including an aromatic ring, Further, a polyimide containing a fluorine atom is preferably used from the viewpoint of improving transparency.
The fluorine atom content ratio is preferably such that the ratio (F / C) of the number of fluorine atoms (F) and the number of carbon atoms (C) measured on the polyimide surface by X-ray photoelectron spectroscopy is 0.01 or more, Further, it is preferably 0.05 or more. On the other hand, if the fluorine atom content is too high, the inherent heat resistance of the polyimide may be reduced, so the ratio (F / C) of the number of fluorine atoms (F) to the number of carbon atoms (C) is 1 or less. Preferably, it is preferably 0.8 or less.
Here, the said ratio by the measurement of X-ray photoelectron spectroscopy (XPS) can be calculated | required from the value of atomic% of each atom measured using an X-ray photoelectron spectrometer (for example, Thermo Scientific Thea Probe). .

In addition, a polyimide in which 70% or more of hydrogen atoms bonded to carbon atoms contained in polyimide are hydrogen atoms directly bonded to an aromatic ring is preferably used from the viewpoint of improving transparency. The proportion of hydrogen atoms (number) directly bonded to the aromatic ring in the total hydrogen atoms (number) bonded to carbon atoms contained in the polyimide is further preferably 80% or more, and more preferably 85% or more. It is preferable that
Such a polyimide is preferable from the viewpoint of little change in optical characteristics, particularly total light transmittance and yellowness YI value, even after a heating step in the air. When polyimide is a polyimide in which more than 70% of the hydrogen atoms bonded to carbon atoms contained in the polyimide are hydrogen atoms directly bonded to the aromatic ring, the chemical structure of the polyimide changes due to low reactivity with oxygen. It is estimated that it is difficult. In addition, when manufacturing a display device using the laminate of the present invention, it is not necessary to carry out a process involving heating in an inert atmosphere in order to maintain transparency, so that it is necessary to control equipment costs and atmosphere. There is an advantage that the cost can be suppressed.
Here, the ratio of the hydrogen atoms (number) directly bonded to the aromatic ring in the total hydrogen atoms (number) bonded to the carbon atoms contained in the polyimide is determined by high-performance liquid chromatography or gas chromatography mass of the polyimide decomposition product. It can be determined using an analyzer and NMR. For example, the sample is decomposed with an alkaline aqueous solution or supercritical methanol, and the resulting decomposition product is separated by high performance liquid chromatography, and a qualitative analysis of each separated peak is performed by a gas chromatograph mass spectrometer, NMR, etc. The ratio of hydrogen atoms (numbers) directly bonded to the aromatic ring in the total hydrogen atoms (numbers) contained in the polyimide can be determined by performing determination using high performance liquid chromatography.

  Further, the polyimide used in the present invention may contain a polyamide structure in a part thereof as long as the effects of the present invention are not impaired. Examples of the polyamide structure which may be included include a polyamideimide structure containing a tricarboxylic acid residue such as trimellitic anhydride and a polyamide structure containing a dicarboxylic acid residue such as terephthalic acid.

  A polyimide is obtained by reacting a tetracarboxylic acid component and a diamine component. It is preferable to obtain imidization by obtaining a polyamic acid by polymerization of a tetracarboxylic acid component and a diamine component. The imidization may be performed by thermal imidization or chemical imidization. Moreover, it can also manufacture by the method which used thermal imidation and chemical imidization together.

(2) Characteristics and configuration of base material for display device The base material for display device may contain other components as long as the effects of the present invention are not impaired. Examples of other components include binder resins other than the polyimide having the above-described predetermined structure, photosensitive polyimide resins, and the like. In addition, various organic or inorganic low-molecular or high-molecular compounds may be included from the viewpoint of imparting processing characteristics and various functionalities. For example, dyes, surfactants, leveling agents, plasticizers, fine particles and the like can be used. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, inorganic fine particles such as colloidal silica, carbon, and layered silicate, and these may have a porous or hollow structure. The function or form includes pigments, fillers, fibers, and the like.

  When the base material for display apparatuses contains the other said component, it is preferable that the mixture ratio exists in the range of 0.1 to 20 mass%. When the mixing ratio of the other components is within the above range, the effects of the other components can be sufficiently exhibited.

The glass transition temperature of the substrate for display device can be appropriately adjusted according to the material constituting the substrate for display device, and is not particularly limited, but is preferably 250 ° C. or higher from the viewpoint of heat resistance, Furthermore, it is preferable that it is 270 degreeC or more. On the other hand, it is preferably 400 ° C. or lower, more preferably 380 ° C. or lower, from the viewpoint of reducing the heat treatment temperature when producing the display device substrate.
The glass transition temperature is determined from the peak temperature of tan δ (tan δ = loss elastic modulus (E ″) / storage elastic modulus (E ′)) by dynamic viscoelasticity measurement. As the dynamic viscoelasticity measurement, for example, with a dynamic viscoelasticity measuring device RSA III (TA Instruments Japan Co., Ltd.), the measurement range is 25 ° C. or higher and 400 ° C. or lower, the frequency is 1 Hz, the temperature is increased. This can be done at a rate of 5 ° C./min. Further, the measurement can be performed with a sample width of 5 mm and a distance between chucks of 20 mm.

It is preferable that the base material for display apparatuses has a low linear thermal expansion coefficient from a viewpoint of dimensional stability. When the functional layer is disposed on the substrate for the display device, it is possible to suppress a decrease in adhesion with the functional layer, and when the functional layer is in a pattern shape, a positional deviation from the functional layer is possible. Can be suppressed. The specific linear thermal expansion coefficient of the substrate for display device is, for example, preferably within a range of −10 ppm / ° C. to 40 ppm / ° C., more preferably 20 ppm / ° C. or less, and 10 ppm / ° C. The following is more preferable.
Here, the linear thermal expansion coefficient in the present invention can be obtained by a thermomechanical analyzer (TMA). Using a thermomechanical analyzer (for example, Thermo Plus TMA8310 (manufactured by Rigaku Corporation)), the heating rate is 10 ° C./min, and the tensile load is 1 g / 25000 μm ² so that the load per cross-sectional area of the evaluation sample is the same. .

  Moreover, it is preferable that the base material for display apparatuses has flexibility. The flexibility of the base material for display device can be appropriately adjusted according to the material constituting the base material for display device, the thickness of the base material for display device, etc. Using a desktop durability tester (Yuasa System Equipment Co., Ltd. DLDMMLH-FS), a planar body U-shaped folding test with a bending radius of 3 mm (R = 3 mm) was performed 100,000 times, and then the substrate for a display device was used. It is preferable that no cracks or scratches occur, and the change in the total light transmittance of the substrate for display device before and after the planar body U-shaped folding test is preferably within 10%.

Moreover, the base material for display apparatuses is 5 mm or less in diameter of the mandrel which begins to crack and bend | fold according to the bending resistance test (cylindrical mandrel method) as described in JIS K5600-5-1 from the point of flexibility. It is preferable that the mandrel has a diameter of 2 mm or less.
The bending resistance test can be performed according to JIS K5600-5-1 type 1, and a coating film bending tester No. 514 (manufactured by Yasuda Seiki Seisakusho) can be used. As a measurement sample, for example, a rectangular sample having a size of 100 mm × 50 mm can be used after being conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%.

  Although the thickness of the base material for display devices can be suitably adjusted according to the use of the laminate of this embodiment, etc., from the viewpoint of flexibility, it is preferably within the range of 3 μm or more and 12 μm or less, especially 3 μm or more. It is preferably within a range of 10 μm or less.

  As will be described later, when the functional layer is disposed on the display device substrate, the display device substrate includes, for example, a saponification treatment, a glow discharge treatment, a corona discharge treatment, an ultraviolet treatment, a flame treatment, and the like. Processing may be performed.

(3) Forming method of base material for display device As a forming method of the base material for display device, for example, a polyimide precursor solution containing polyamic acid is applied on a supporting base material and temporarily dried, and then the polyimide precursor coating is applied. Examples include a method including a polyimide precursor coating film forming step for forming a film and an imidization step in which the polyimide precursor coating film is imidized by heat treatment and the polyimide precursor coating film is used as a polyimide film.
Hereinafter, the polyimide precursor coating film forming step and the imidization step will be described.

(A) Polyimide precursor coating film forming step The polyimide precursor coating film forming step is a step of forming a polyimide precursor coating film by applying a polyimide precursor solution containing a polyamic acid on a supporting substrate and pre-drying it. It is.

  As a method of applying the polyimide precursor solution on the support substrate, a general application method can be used, for example, spin coating method, die coating method, dip coating method, bar coating method, gravure printing method, screen printing. The law etc. can be used.

  As a method of temporarily drying the polyimide precursor solution coated on the support substrate, for example, a method of drying to such an extent that a desired polyimide precursor coating film is obtained is preferable. That is, it is preferable that the solvent is contained in a desired range so that the content of the solvent contained in the polyimide precursor coating film is within a desired range, and drying is performed so that imidization does not proceed.

  As a specific method of temporary drying, a method of drying the polyimide precursor solution coated on the supporting substrate by heating can be mentioned. As the heating method at this time, for example, a known apparatus or method such as an oven or a hot plate can be used. The heating temperature is preferably such that the polyimide precursor solution applied on the supporting substrate can be temporarily dried and imidization does not proceed. The specific heating temperature can be appropriately adjusted according to the composition of the polyimide precursor solution, the heating time, and the like. For example, the heating temperature is preferably in the range of 40 ° C. or higher and 200 ° C. or lower. It is preferable that it is in the range of not higher than ° C., particularly preferably in the range of 80 ° C. or higher and 120 ° C. or lower. Furthermore, the heating time can be appropriately adjusted according to the heating temperature or the like, and can be set to about 90 seconds to 90 minutes, for example. When the heating temperature at the time of temporary drying is within the above range, a desired polyimide precursor coating film can be obtained.

The weight average molecular weight of the polyamic acid depends on its use, but is preferably in the range of 3,000 to 1,000,000, for example, in the range of 5,000 to 500,000. Is more preferable, and it is further preferable to be within the range of 10,000 to 500,000. By having the said minimum, sufficient intensity | strength can be obtained when a polyimide precursor coating film or a polyimide film is formed using the polyimide precursor solution containing a polyamic acid. Moreover, by having the said upper limit, the fall of the solubility of a polyamic acid can be suppressed, and the polyimide precursor coating film or polyimide film with a smooth surface and uniform film thickness can be obtained.
The weight average molecular weight refers to a value in terms of polystyrene by gel permeation chromatography (GPC), and may be the molecular weight of the polyamic acid itself or the molecular weight after imidization treatment.

The content of polyamic acid in the polyimide precursor solution is preferably 50% by mass or more, more preferably 70% by mass or more, based on the entire solid content of the polyimide precursor solution.
In addition, solid content of a polyimide precursor solution is all components other than a solvent, and a liquid monomer component is also contained in solid content.

The polyimide precursor solution usually contains a solvent in addition to the polyamic acid described above. The solvent is preferably a solvent that can uniformly disperse or dissolve the polyamic acid. For example, ethers such as diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol mono Glycol monoethers such as ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether (so-called cellosolves); ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclopentanone, cyclohexanone; ethyl acetate, butyl acetate, n-acetate Propyl acetate i-propiate , N-butyl acetate, i-butyl acetate, acetate esters of the above glycol monoethers (for example, methyl cellosolve acetate, ethyl cellosolve acetate), esters such as methoxypropyl acetate, ethoxypropyl acetate, dimethyl oxalate, methyl lactate, ethyl lactate Alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, glycerin; methylene chloride, 1,1-dichloroethane, 1,2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloro Halogenated hydrocarbons such as pentane, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene; N, N-dimethylformamide, N, N-diethylphenol Amides such as muamide, N, N-dimethylacetamide, N, N-diethylacetamide; Pyrrolidones such as N-methylpyrrolidone; Lactones such as γ-butyrolactone; Sulfoxides such as dimethylsulfoxide; Other organic polar solvents Etc. Furthermore, aromatic hydrocarbons such as benzene, toluene and xylene, and other organic nonpolar solvents are also included. These solvents are used alone or in combination.
Among them, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexa Polar solvents such as methylphosphoamide, N-acetyl-2-pyrrolidone, pyridine, dimethyl sulfone, tetramethylene sulfone, dimethyltetramethylene sulfone, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone It is mentioned as a suitable thing.

  The polyimide precursor solution contains, for example, polyamic acid, a solvent, etc., but may contain other components as necessary. Since the other components have been described above, description thereof is omitted here.

  The thickness of the polyimide precursor coating film can be appropriately adjusted according to the use of the laminate of this embodiment, but can be, for example, 3 μm or more and 50 μm or less, and can be 4 μm or more and 20 μm or less. In particular, it can be 5 μm or more and 15 μm or less. When the thickness of the polyimide precursor coating film is within the above range, a polyimide film having a desired thickness can be obtained, and by using a coating method, the polyimide film can be thinned as in the above range. It becomes possible to plan.

(B) Imidization process An imidation process is a process which imidizes by heat-treating a polyimide precursor coating film, and makes a polyimide precursor coating film a polyimide film.

  As a method of heat-treating the polyimide precursor coating film, for example, a method of heating using an oven, a hot plate or the like can be mentioned.

  In general, it is said that imidization of polyamic acid gradually proceeds from about 150 ° C., and imidization is almost completed at a temperature of 200 ° C. or higher. On the other hand, in order to obtain a higher degree of reliability, it is necessary to advance imidization more completely. In that case, a temperature close to the glass transition temperature of the finally obtained polyimide film, in particular, the polyimide film It is preferable to perform heating at a temperature higher than the glass transition temperature.

  The heat treatment temperature is preferably adjusted as appropriate according to the glass transition temperature of the polyimide film for the purpose of favorably progressing imidization. The specific heat treatment temperature is preferably in the range of 210 ° C. or more and 380 ° C. or less, for example, preferably in the range of 260 ° C. or more and 370 ° C. or less, and particularly in the range of 280 ° C. or more and 360 ° C. or less. It is preferable that

  The heat treatment time can be appropriately adjusted according to the above-described heat treatment temperature, polyimide film material, and the like, and is not particularly limited. For example, the heat treatment time may be about 30 minutes to 120 minutes.

  The heat treatment may be performed in either an inert atmosphere or an air atmosphere. In the case of an inert atmosphere such as nitrogen or argon, oxidation of the polyimide film can be prevented. On the other hand, the cost can be reduced in the case of an air atmosphere. In addition, the polyimide used for this invention has little influence of oxygen with respect to an optical characteristic, and even if it does not use an inert atmosphere, a highly transparent polyimide film is obtained.

In the imidization step, it is preferable that imidization proceeds more completely. The imidation ratio of the polyimide precursor coating film is preferably such that the polyimide precursor coating film can be cured to form a polyimide film, and specifically, 80% or more is preferable. % Or more, preferably 100%, that is, not containing polyamic acid.
The imidization rate can be confirmed using, for example, an infrared absorption spectrum. Specifically, it can be determined by quantifying from the peak area of the C═O double bond derived from the imide bond contained in the polyimide film.

2. Support base material The support base material used for this aspect is a member which supports the base material for display apparatuses.

  As the material of the support base material, for example, a material that can be applied with a polyimide precursor solution on the surface can be adopted. Specifically, a flexible material such as quartz glass, Pyrex (registered trademark) glass, or synthetic quartz plate can be used. Inorganic substrates having no property are listed.

  For example, when the support substrate is peeled from the laminate, a release treatment can be performed on the surface on the side in contact with the display device substrate in order to exhibit excellent peelability. Examples of the release treatment method include a method of forming a release layer on the surface of the support substrate. The release layer can be formed by applying and drying a release agent. Examples of the release agent used at this time include, for example, a melamine resin release agent, a silicone resin release agent, a fluororesin release agent, a cellulose resin release agent, a urea resin release agent, and a polyolefin resin. Examples include release agents, paraffin release agents, acrylic resin release agents, and composite release agents thereof.

  The thickness of the supporting base material is preferably a thickness that can support each member and can be peeled off from the laminate as necessary. The specific thickness of the support substrate can be appropriately adjusted according to the flexibility of the laminate, that is, the material constituting the laminate, and is not particularly limited. For example, it can be 3 μm or more and 50 μm or less.

3. Functional layer In this aspect, the functional layer 4 may be arrange | positioned on the base material 3 for display apparatuses, as illustrated in FIG.

A functional layer can be suitably selected according to the use of the layered product of this mode. Examples of the functional layer include a barrier layer, a sensor electrode, a black matrix, a colored portion, an anchor layer, a decorative portion, an overcoat layer, a TFT, and a stress relaxation layer. The functional layer may be a single layer, or a plurality of types of functional layers may be laminated.
Especially, it is preferable that a functional layer is a layer which performs the process accompanied by the heating for the formation, especially the process accompanied by the heating of 100 degreeC or more and 240 degrees C or less under an air atmosphere. This is because yellowing of the display device substrate due to a process involving heating can be effectively suppressed. Examples of such a functional layer include a black matrix, a colored portion, a barrier layer, an anchor layer, and a decorative portion. Moreover, as a material of such a functional layer, for example, an ultraviolet curable resin or a thermosetting resin is preferably used.
Hereinafter, specific examples of the functional layer will be described.

(1) Barrier layer When the laminate of this embodiment is used in a display device, the barrier layer can suppress the intrusion of oxygen, water vapor, or the like, or protect the display device substrate from a chemical solution.

The material of the barrier layer may be an inorganic material or an organic material. Among these, an organic material is preferably used because a process involving heating is performed.
Examples of the inorganic material used for the barrier layer include inorganic oxides, inorganic nitrides, inorganic oxynitrides, and inorganic carbides. Specific examples of inorganic oxides include silicon oxide, indium oxide, aluminum oxide, titanium oxide, tantalum oxide, zinc oxide, magnesium oxide, tin oxide, yttrium oxide, germanium oxide, calcium oxide, boron oxide, strontium oxide, and oxide. Examples include barium, lead oxide, zirconium oxide, sodium oxide, lithium oxide, and potassium oxide. Examples of the inorganic nitride include silicon nitride, aluminum nitride, titanium nitride, and silicon carbonitride. Examples of inorganic oxynitrides include silicon oxynitride. Moreover, silicon carbide etc. are mentioned as an inorganic carbide. These may be used alone or in combination of two or more.
Moreover, as an organic material used for a barrier layer, the resin material which has alkali resistance or acid resistance is mentioned. Specific examples include polycarbonate resins, polyolefin resins, acrylic resins, urethane resins, silicone resins, polyester resins, and epoxy resins.

  Furthermore, the barrier layer may be an inorganic-organic mixed barrier layer containing a polymer composition and a metal compound. Examples of the metal compound include monovalent metals such as Li, Na, K, and Rb, oxides of divalent or higher metals such as Mg, Ca, Zn, Cu, Co, Fe, Ni, Al, and Zr, and hydroxide. Inorganic salts such as carboxylic acid salts, carbonates and sulfates, and organic acid salts such as carboxylates and sulfonic acids. Examples of the polymer composition include a crosslinked product of polycarboxylic acid and polyalcohol, a crosslinked product of polycarboxylic acid and polyamine, and the like. Specific examples of the polycarboxylic acid, polyalcohol, and polyamine include materials described in International Publication No. 2014/042133. Note that the metal compound contained in the inorganic-organic mixed barrier layer may be one kind or plural kinds.

  The barrier layer may be one layer or two or more layers may be laminated. In the case of two or more layers, the material of each barrier layer may be different. For example, a barrier layer containing an inorganic material and a barrier layer containing an organic material may be alternately laminated.

  In addition, as will be described later, when the laminate of this embodiment has a stress relaxation layer and a barrier layer in order from the display device substrate side as a functional layer, the material of the barrier layer adjacent to the stress relaxation layer is An organic material is preferable. When the thickness of the stress relaxation layer is relatively thin, the unevenness on the surface of the substrate for display device may be reproduced as it is in the stress relaxation layer, but there is a barrier layer containing an organic material adjacent to the stress relaxation layer. When arranged, the surface can be smoothed by the barrier layer.

  Furthermore, as will be described later, when the laminate of this embodiment has a stress relaxation layer and two or more barrier layers in order from the display device substrate side as the functional layer, as described above, the stress relaxation The material of the first barrier layer adjacent to the layer is preferably an organic material. Moreover, the material of each barrier layer may differ as mentioned above, for example, the barrier layer containing an inorganic material and the barrier layer may be laminated | stacked alternately. That is, since the material of the first barrier layer adjacent to the stress relaxation layer is preferably an organic material, a barrier layer containing an organic material and a barrier layer containing an inorganic material in this order from the stress relaxation layer side. And may be alternately stacked.

  In the case of two or more barrier layers, the number of barrier layers may be two or more, but may be, for example, two or more and six or less.

  The method for forming the barrier layer can be appropriately selected depending on the material of the barrier layer. For example, when the barrier layer contains an inorganic material, a sputtering method, a vacuum deposition method, a plasma CVD method, and the like can be given. When the barrier layer contains an organic material, it is applied to a display device substrate using a coating method such as spin coating, roll coating, or gravure roll coating, or the barrier layer is formed independently and used for a display device. The method etc. which are bonded together via the adhesion layer etc. to the surface of a substrate are mentioned. Moreover, when a barrier layer is an inorganic-organic mixed barrier layer, a sol-gel method is mentioned.

  The thickness of the barrier layer can be appropriately adjusted according to the material of the barrier layer, the use of the laminate of this embodiment, and the like, and is not particularly limited.

(2) Sensor electrode When the functional layer is a sensor electrode, the laminate of this embodiment can be used as a touch sensor panel.

  The sensor electrode may have transparency or may have opacity. When the sensor electrode has transparency, it can be a transparent conductive layer. On the other hand, when the sensor electrode is opaque, it can be a mesh electrode with a fine line. In addition, the sensor electrode is preferably formed in a pattern, and specifically, it is preferably a mesh electrode with a fine line.

  Examples of the material of the sensor electrode include silver, gold, copper, chromium, platinum, aluminum alone, or an alloy mainly composed of any of these. As the metal alloy, an alloy of silver, palladium and copper called APC is widely used. As the metal composite, a three-layer structure of molybdenum, aluminum, and molybdenum called MAM is also applicable. Furthermore, for example, a conductive polymer such as PEDOT-PSS can be used. Furthermore, a transparent conductive material such as tin oxide, indium tin oxide called ITO, or indium zinc oxide called IZO can be used.

  When the sensor electrode is a fine mesh mesh electrode, the thickness, line width, pitch, aperture ratio, etc. of the sensor electrode can be appropriately adjusted according to the use of the laminate of this embodiment, Since it can be the same as that of the sensor electrode, description thereof is omitted here. Since the sensor electrode is a mesh electrode with a fine line, even if the material used for the sensor electrode is an opaque metal material, it can be an apparently transparent sensor electrode.

  As a method for forming the sensor electrode, for example, first, a conductive layer is formed using a conductive material that is a constituent material of the sensor electrode, and then a resist pattern is formed on the conductive layer, and the resist pattern is used as a mask to conduct electricity. A method of etching the layer is mentioned. At this time, for example, a dry process such as a vacuum deposition method, a sputtering method, a CVD method, or an ion plating method can be used as a method for forming the conductive layer.

  When the functional layer is a sensor electrode, an invisible layer or a shock absorbing layer that can suppress bone appearance of the transparent electrode layer that is the sensor electrode may be formed.

(3) Black matrix When the functional layer is a black matrix, the laminate of this embodiment can be used as a light shielding member.

  The black matrix can contain, for example, a binder resin and a black pigment. Examples of the black pigment include titanium black such as low-order titanium oxide and titanium oxynitride, and carbon black. Moreover, it is preferable that binder resin used as the main component of a black matrix contains photosensitive resin. Examples of the photosensitive resin include 1 photosensitive resin having a photoreactive group such as a reactive vinyl group such as an acrylic resin, an epoxy resin, a polyimide resin, a polyvinyl cinnamate resin, and a cyclized rubber. More than one species can be used. In the acrylic resin, for example, a photosensitive resin composed of an alkali-soluble resin, a polyfunctional acrylate monomer, a photopolymerization initiator, and other additives can be used as the resin component of the binder resin. The binder resin can contain various known additives such as a photosensitizer, a dispersant, a surfactant, a stabilizer, and a leveling agent in addition to the materials described above.

  The thickness, line width, light shielding property, etc. of the black matrix can be adjusted as appropriate according to the use of the laminate of this embodiment, and can be the same as that of a general black matrix. Omitted.

  The method for forming the black matrix is appropriately selected depending on the material, and includes, for example, a photolithography method.

(4) Colored portion When the functional layer is a colored portion, the laminate of this embodiment can be used as a color filter.
Further, as described above, when the functional layer is a black matrix, a colored portion may be formed as another functional layer in the opening of the patterned black matrix. Also in this case, the laminate of this embodiment can be used as a color filter.
In addition, since a coloring part can be made to be the same as that of the coloring part used for a general color filter, description here is abbreviate | omitted.

(5) Anchor layer An anchor layer is a layer which can improve the platemaking property and adhesiveness of the other functional layer arrange | positioned on an anchor layer. With the anchor layer, it is possible to prevent other functional layers from being peeled off from the base material for display device and other functional layers from cracking.

The anchor layer preferably has a predetermined transparency. When the laminated body of this embodiment is used for a display device, it is possible to suppress a decrease in transmittance due to provision of an anchor layer. Specifically, the visible light transmittance of the anchor layer is, for example, preferably 75% or more, more preferably 85% or more, and particularly preferably 95% or more.
The visible light transmittance was measured by using a infrared visible ultraviolet spectrophotometer (UV3100PC manufactured by Shimadzu Corporation) and measuring the spectral transmittance in a wavelength range of 380 nm to 780 nm according to JIS A5759-2008. It can be calculated by a calculation formula defined in the above.

Examples of the material of the anchor layer include curable resins such as ionizing radiation curable resins and thermosetting resins. Examples of the ionizing radiation curable resin include polymers having at least one ionizing radiation curable functional group selected from the group consisting of a vinyl group, a (meth) acryloyl group, an allyl group, and an epoxy group. Specifically, acrylic (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, and the like can be given. Examples of the thermosetting resin include phenol / formaldehyde resin, urea / formaldehyde resin, melamine / formaldehyde resin, resin obtained by curing acrylic polyol with isocyanate, resin obtained by curing polyester polyol with isocyanate, and acrylic acid with melamine. Examples include cured resins.
In addition to the curable resin described above, examples of the material for the anchor layer include silicon oxide and silicon nitride.

  When a curable resin is used as the material for the anchor layer, the anchor layer can be formed by applying and curing the anchor layer forming composition on the substrate for a display device. Examples of the coating method at this time include general methods such as a gravure coating method, a roll coating method, a comma coating method, a gravure printing method, a screen printing method, and a gravure reverse roll coating method. When silicon oxide or silicon nitride is used as the material for the anchor layer, the anchor layer can be formed using a sputtering method, an ion beam method, an ion plating method, or the like.

  The thickness of the anchor layer is not limited as long as it can improve the heat resistance of the laminate of this embodiment and the adhesion of other functional layers disposed on the anchor layer, but it exhibits flexibility in particular. It is preferable that the adhesion of other functional layers can be improved and cracks of other functional layers can be suppressed. Specifically, the thickness of the anchor layer is preferably 3 μm or less, more preferably 2 μm or less, and particularly preferably 0.8 μm or less. When the thickness of the anchor layer is within the above range, it is possible to sufficiently obtain the effects of improving the heat resistance of the laminate of this embodiment and improving the adhesion of other functional layers. Moreover, the thickness of an anchor layer can be 0.1 micrometer or more, for example. When the thickness of the anchor layer is within the above range, the anchor layer can be formed on the entire surface of the display device substrate, and the function as the anchor layer can be exhibited.

(6) Decoration part A decoration part is a layer which can improve the external appearance of a display apparatus by exhibiting a predetermined color. As a color which a decoration part exhibits, it can select suitably according to the design etc. of the display apparatus in which the laminated body of this aspect is used.
When a functional layer is a decoration part, the laminated body of this aspect can be used as a decorating member.

  As a material of the decoration part, it can select suitably according to the color which a decoration part exhibits. When the decorating part is a black decorating part exhibiting black, the material of the black decorating part can be the same as the material of the above-described black matrix, and thus description thereof is omitted here. Moreover, when the decoration part is a white decoration part that exhibits white, for example, titanium oxide, silica, talc, kaolin, clay, barium sulfate, calcium hydroxide, or the like is used as the material of the white decoration part. it can.

  As a formation method of a decoration part, a decoration part is formed by patterning a decoration layer by sputtering method, a vacuum evaporation method, the apply | coating method etc., and patterning a decoration layer by the photolithographic method after that, for example. A method is mentioned.

  The thickness of the decorative portion can be appropriately adjusted according to the use of the laminate of this embodiment, and is not particularly limited.

(7) Overcoat layer The material of the overcoat layer can be the same as that of a general overcoat layer. Examples thereof include organic materials such as acrylic resins, phenolic resins, fluorine resins, epoxy resins, cardo resins, vinyl resins, imide resins, and novolac resins.

  The thickness of the overcoat layer can be appropriately adjusted according to the use of the laminate of this embodiment, and is not particularly limited.

  Examples of the method for forming the overcoat layer include a method of applying a composition for forming an overcoat layer. As a coating method, generally known coating methods can be applied. For example, a coating method such as spin coating, roll coating, cast coating and the like can be mentioned.

(8) TFT
When the functional layer is a TFT, the laminate of this embodiment can be used as a TFT array.
As the TFT, a general one can be used.

(9) Stress relaxation layer The polyimide contained in the base material for display devices in the present invention includes an aromatic ring and has a rigid molecular structure. Therefore, when a functional layer is disposed on a display device substrate, cracks and warpage may occur due to the difference between the expansion and contraction of the display device substrate and the functional layer. In addition, even when the functional layer disposed on the display device base material is an organic film, the difference in expansion and contraction between the display device base material and the functional layer in the process of forming the functional layer is large. In the case where the functional layer is destroyed by the interaction of stress generated in the layer, a crack is generated in the functional layer, and even if the functional layer is not destroyed, warping may occur. On the other hand, when the stress relaxation layer is located adjacent to the display device base material, the display device base material and the other substrate in the process of forming another functional layer disposed on the stress relaxation layer are provided. Stress can be relaxed by the stress relaxation layer due to the difference in expansion and contraction with the functional layer. Therefore, when another functional layer is disposed on the stress relaxation layer, generation of cracks and warpage can be suppressed. That is, it is preferable that the laminated body of this aspect has a stress relaxation layer and another functional layer in order from the display apparatus base material side as a functional layer.

  Furthermore, also when arrange | positioning the base material for display apparatuses on a support base material, there exists a tendency for curvature to generate | occur | produce by the stress of the base material for display apparatuses. On the other hand, by arranging the stress relaxation layer on the display device substrate, it is possible to suppress the occurrence of warpage when the display device substrate is disposed on such a support substrate. .

  In addition, since the generation of cracks and warpage can be suppressed by the stress relaxation layer, even if the functional layer has a thin line width such as a black matrix or wiring, a fine functional layer is disposed without causing breakage. can do.

  Examples of other functional layers disposed on the stress relaxation layer include a barrier layer, a sensor electrode, a black matrix, a colored portion, a decorative portion, and an overcoat layer.

  Moreover, it is preferable that the material of the functional layer adjacent to a stress relaxation layer among other functional layers arrange | positioned on a stress relaxation layer is an organic material. When the thickness of the stress relaxation layer is relatively thin, the unevenness on the surface of the substrate for display device may be reproduced as it is in the stress relaxation layer, but there is a functional layer containing an organic material adjacent to the stress relaxation layer. When arranged, the surface can be smoothed by this functional layer. Examples of the organic material include a resin material, and specific examples include an ultraviolet curable resin and a thermosetting resin.

  Especially, it is preferable that the other functional layer arrange | positioned on a stress relaxation layer is a barrier layer. That is, it is preferable that the laminated body of this aspect has a stress relaxation layer and a barrier layer in order from the base material side for display apparatuses as a functional layer. The stress relaxation layer relieves the stress caused by the expansion / contraction difference between the display device substrate and the barrier layer during the formation process of the barrier layer, thereby preventing the barrier layer from cracking and warping and reducing the barrier properties. be able to. Further, when another functional layer is further disposed on the barrier layer, the stress relaxation layer causes stress due to a difference in expansion and contraction between the display device substrate and the other functional layer in the process of forming the other functional layer. By relaxing, it is possible to suppress the occurrence of cracks and warpage in other functional layers.

  In particular, the laminate of this embodiment preferably has, as a functional layer, a stress relaxation layer and two or more barrier layers in order from the display device substrate side. For example, the laminated body 1 shown in FIG. 3 has the support base material 2, the display device base material 3, and the functional layer 4 in this order. In order, it has a stress relaxation layer 21 and two barrier layers 22 and 23. The stress relaxation layer relieves the stress caused by the expansion / contraction difference between the display device substrate and the barrier layer during the formation process of the barrier layer, thereby preventing the barrier layer from cracking and warping and reducing the barrier properties. In addition, the barrier property can be improved by increasing the number of barrier layers stacked.

  The stress relaxation layer is not particularly limited as long as it can relieve stress. Examples of the material include inorganic oxides, inorganic nitrides, inorganic carbides, inorganic sulfides, and inorganic materials. Examples thereof include oxynitrides, inorganic oxycarbides, and inorganic carbonitrides. Specifically, selected from the group consisting of silicon carbide, silicon oxide, silicon oxide carbide, silicon carbonitride, silicon nitride, silicon nitride oxide, aluminum oxide, indium tin oxide, indium zinc oxide, zinc oxide, and tin oxide. At least one can be mentioned.

  The thickness of the stress relaxation layer is, for example, 10 nm from the point of relaxing stress caused by the difference between the expansion and contraction of the other functional layer and the expansion and contraction of the substrate for display device when another functional layer is disposed on the stress relaxation layer. Of these, 50 nm or more is preferable, and 100 nm or more is particularly preferable. Further, the thickness of the stress relaxation layer can be, for example, 5000 nm or less, preferably 3000 nm or less, from the viewpoint of bending resistance of the laminate, transparency, time required for forming the stress relaxation layer, and the like. In particular, it is preferably 2000 nm or less.

  Moreover, it is preferable that a stress relaxation layer has a structure from which a density differs in the thickness direction. In this case, the stress relaxation layer may have a structure in which layers having different densities are stacked, or may have a structure in which the density gradually changes in the thickness direction. Due to the presence of a dense interface or density change inside the stress relaxation layer, the stress caused by the difference in expansion and contraction between the layers above and below the stress relaxation layer is more dispersed, and the stress relaxation is made more effective. The

  As a method for forming the stress relaxation layer, for example, a vacuum film forming method such as a sputtering method or a vapor deposition method can be used.

4). Structure of laminated body The laminated body of this aspect may have other members as needed in addition to the above-mentioned members.

  The laminated body of this aspect can be variously configured according to the functional layer.

5. Use of laminated body The laminated body of this aspect is used for manufacture of a display apparatus. Examples of the display device include an organic EL display device, a liquid crystal display device, and electronic paper. Especially, it can use suitably for a flexible display apparatus.

B. 2nd aspect The laminated body of this aspect is arrange | positioned on the support base material, the said adhesion layer arrange | positioned on the said support base material, and the said adhesion layer, contains an aromatic ring, and the said General formula (1) And a substrate for a display device containing a polyimide having at least one structure selected from the group consisting of the structure represented by the general formula (3).

  FIG. 4 is a schematic cross-sectional view showing an example of the laminate of this embodiment. As shown in FIG. 4, the laminate 1 includes a support base 2, an adhesive layer 5 disposed on the support base 2, and a display device base 3 disposed on the adhesive layer 5. ing.

  In addition, since it is the same as that of the said 1st aspect about the structure of a support base material, a laminated body, and the use of a laminated body, description here is abbreviate | omitted. Hereinafter, the other structure in the laminated body of this aspect is demonstrated.

1. Base material for display device The base material for display device in this aspect is a member which contains the polyimide which is arrange | positioned on the adhesion layer and has a predetermined structure.

  The thickness of the base material for display devices can be appropriately adjusted according to the use of the laminate of this embodiment, and is preferably in the range of 12 μm to 100 μm, for example.

  As a method of arranging the display device substrate on the support substrate through the adhesive layer, for example, using a display device substrate prepared in advance, the display device substrate is provided on the support substrate through the adhesive layer. The method of bonding a base material is mentioned.

  In addition, about the characteristic, a structure, etc. of a polyimide and the base material for display apparatuses, since it is the same as that of the said 1st aspect, description here is abbreviate | omitted.

2. Adhesive layer Examples of the adhesive layer used in this embodiment include an ultraviolet curable adhesive layer made of an ultraviolet curable resin material and cured by irradiation with ultraviolet light, and a pressure sensitive adhesive layer made of a pressure sensitive adhesive. Can be mentioned.

  The ultraviolet curable resin material used for the ultraviolet curable adhesive layer is not particularly limited as long as it is a material that can be cured by irradiating ultraviolet rays having a wavelength in the range of 100 nm to 450 nm, for example. For example, monofunctional monomers such as reactive ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, and polyfunctional monomers, polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate , Triethylene (polypropylene) glycol (meth) diacrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Isocyanuric acid EO-modified diacrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenolfluorene derivative, Scan phenoxyethanol fluorene (meth) acrylate, bisphenol fluorene Epo Kiki (meth) acrylate. Here, (meth) acrylate is a notation meaning acrylate or methacrylate. Only one kind of these ultraviolet curable resins may be used, or two or more kinds may be mixed and used.

  Examples of the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer include, for example, an adhesive main agent, a rubber latex of styrene-butadiene rubber (SBR) or acrylonitrile-butadiene rubber (NBR) obtained by soap-free emulsion polymerization, or polyacryl. Examples thereof include acrylic resin latexes such as acid esters, and, if necessary, as latex by further usual emulsion polymerization, styrene-butadiene rubber (SBR), carboxy-modified SBR (XSBR), acrylonitrile-butadiene rubber (NBR), Alternatively, an acrylic resin latex adhesive such as acrylic modified natural rubber (PMMA-NR) or polyacrylic acid ester is used in combination, and a filler such as resin particles made of polystyrene or the like as a filler, or a conventionally known one. A mixture of these fillers can be used.

  It is preferable that the pressure-sensitive adhesive layer has such a degree of adhesiveness that the support substrate can be peeled off. That is, the peel strength of the adhesive layer with respect to the supporting substrate by the 180-degree peel test specified in JIS K6854-2 is preferably 10 N / 25 mm width or more, more preferably 15 N / 25 mm width or more, particularly 20 N / 25 mm width or more is preferable. The peel strength of the adhesive layer is, for example, preferably 50 N / 25 mm width or less, more preferably 45 N / 25 mm width or less, and particularly preferably 40 N / 25 mm width or less.

3. Functional layer In this aspect, the functional layer 4 may be arrange | positioned on the base material 3 for display apparatuses so that it may illustrate in FIG.
Note that the functional layer is the same as that in the first aspect, and the description thereof is omitted here.

II. Manufacturing method of display device The manufacturing method of a display device of the present invention is opposite to the base material for display device, the functional layer formed on the base material for display device, and the functional layer of the base material for display device. A display device having a display panel disposed on a side surface or the functional layer, comprising an aromatic ring on a support substrate, and the general formula (1) and the general formula A preparation step of preparing a base material for a display device containing polyimide having at least one structure selected from the group consisting of the structure represented by (3), and after the preparation step, on the base material for display device It is a manufacturing method characterized by having a functional layer formation process which forms a functional layer, and a peeling process which peels off the support substrate after the functional layer formation process.

  6A to 6D are process diagrams showing an example of a method for manufacturing a display device of the present invention. First, as shown to Fig.6 (a), the preparatory process which forms the base material 3 for display apparatuses containing the polyimide which has a predetermined structure directly on the support base material 2 is performed. Next, as shown in FIG. 6B, a functional layer forming step for forming the functional layer 4 on the display device substrate 3 is performed. Subsequently, as shown in FIGS. 6B to 6C, a peeling process for peeling the support base material 2 is performed. Next, as shown in FIG.6 (d), the bonding process which bonds the display panel 11 through the adhesive layer 12 to the surface from which the support base material 2 was peeled is performed. In this way, the display device 10 is obtained.

  7A to 7D are process diagrams showing another example of the method for manufacturing a display device of the present invention. First, as shown to Fig.7 (a), the preparation process which forms the base material 3 for display apparatuses containing the polyimide which has a predetermined structure directly on the support base material 2 is performed. Next, as shown in FIG. 7B, a functional layer forming step for forming the functional layer 4 on the display device substrate 3 is performed. Next, as shown in FIG.7 (c), the bonding process which bonds the display panel 11 to the surface in which the functional layer 4 is formed through the adhesive layer 12 is performed. Then, as shown to FIG.7 (c)-(d), the peeling process which peels the support base material 2 is performed. In this way, the display device 10 is obtained.

  According to the present invention, as described in “I. Laminate” above, heating is performed in an air atmosphere in the manufacturing process of a display device by using a base material for a display device containing polyimide having a predetermined structure. Even if the accompanying process is performed, it is possible to suppress changes in the optical characteristics of the display device substrate, in particular, the yellowness YI value and the total light transmittance. Therefore, good display quality can be obtained. Moreover, since it is not necessary to carry out a process involving heating in an inert atmosphere in order to maintain transparency, it is possible to suppress equipment costs and expenses for controlling the atmosphere.

  The method for manufacturing a display device of the present invention can be roughly divided into two modes. Hereinafter, the laminate of the present invention will be described separately for each embodiment.

A. Third Aspect The method for producing a display device according to this aspect is selected from the group consisting of a structure containing an aromatic ring and represented by the general formula (1) and the general formula (3) on a support substrate. A preparation step of preparing a substrate for display device containing polyimide having at least one kind of structure, a functional layer formation step of forming a functional layer on the substrate for display device after the preparation step, and the function A manufacturing method comprising: a peeling step of peeling the support substrate after the layer forming step; and a bonding step of bonding the display panel to the surface from which the support substrate is peeled after the peeling step. is there.
Hereafter, each process in the manufacturing method of the display apparatus of this aspect is demonstrated.

1. Preparatory process The preparatory process in this aspect is a process of preparing the base material for display layers containing the polyimide which has a predetermined structure on a support base material.

Examples of a method for preparing a display device substrate on a support substrate include a method of directly forming a display device substrate on a support substrate, or a display device substrate prepared in advance on a support substrate. There is a method of arranging the materials.
Among these, a method of directly forming a display device substrate on a supporting substrate is preferable. Even if the heat treatment for forming the display device substrate directly on the support substrate is performed in an air atmosphere, changes in optical characteristics, particularly the yellowness YI value and the total light transmittance can be suppressed. In addition, since it is not necessary to perform this heat treatment in an inert atmosphere in order to maintain transparency, it is possible to suppress equipment costs and costs for atmospheric control. Further, the heat treatment holding time can be shortened, and the production cost can be reduced. Further, it is possible to reduce the thickness of the display device substrate.

  The method for forming the display device substrate directly on the support substrate and the method for arranging the display device substrate prepared in advance on the support substrate are described in detail in the above "I. Laminate". Therefore, the description here is omitted.

2. Functional layer formation process The functional layer formation process in this aspect is a process of forming a functional layer on the base material for display apparatuses after the said preparation process. When the functional layer has a pattern shape, the functional layer is also patterned.
In addition, since it described in detail in said "I. laminated body" about the functional layer and its formation method, description here is abbreviate | omitted.

3. Peeling process The peeling process in this aspect is a process of peeling a support base material after a functional layer formation process.

  As a method for peeling the supporting substrate, for example, a method of peeling the supporting substrate by a physical method, or a laser beam that is irradiated with laser light from the supporting substrate side and transmitted through the supporting substrate is a display device substrate. And a method of peeling the support base material and the display device base material.

In the case of a method of irradiating a laser beam from the support substrate side and peeling the support substrate and the display device substrate, the laser beam can break the bond at the interface between the support substrate and the display device substrate. A laser having such a wavelength range can be used. Specifically, it is preferable that the wavelength region of the laser light is an ultraviolet region. For example, the ultraviolet region is preferably in the range of 300 nm to 400 nm, more preferably in the range of 320 nm to 380 nm, and particularly preferably in the range of 340 nm to 360 nm. Examples of such laser light include excimer lasers such as XeCl and XeF, solid lasers such as YAG and YVO ₄ , and semiconductor lasers. For example, when a substrate for a display device is produced using a transparent polyimide precursor solution, an excimer laser of 308 nm or a solid laser of 355 nm can be used.

  The laser light irradiation method is preferably a method that can sufficiently irradiate laser light to the interface between the support base material and the display device base material, in one direction on a plan view of the support base material, There is a method of scanning while moving the exposure apparatus.

  In order to peel the supporting substrate from the display device substrate satisfactorily, a laser absorbing layer that absorbs laser light may be disposed in advance between the supporting substrate and the display device substrate. The material of the laser absorption layer is preferably a material capable of causing laser ablation when irradiated with laser light. The specific material of such a laser absorption layer can be appropriately selected according to the type of laser light and the like, and can be the same as that generally used as a laser absorption layer. Description of is omitted. Further, the thickness and the forming method of the laser absorption layer can be the same as those of a general laser absorption layer, and thus description thereof is omitted here.

4). Bonding step The bonding step in this embodiment is a step of bonding the display panel to the surface from which the support base material has been peeled after the peeling step.

  The method of bonding the display panel to the surface of the display device substrate from which the support substrate is peeled can be the same as the bonding method used in a general display device manufacturing method, for example, an adhesive. The method of crimping | bonding both through a layer is mentioned.

The material of the pressure-sensitive adhesive layer preferably has a predetermined transparency. Among them, it is preferable to have predetermined flexibility. Examples of such a material for the pressure-sensitive adhesive layer include general materials such as a photocurable resin and a thermosetting resin.
The thickness of the pressure-sensitive adhesive layer is preferably a thickness that can exert the adhesive force as the pressure-sensitive adhesive layer, and can be appropriately adjusted according to the material of the pressure-sensitive adhesive layer. In addition, about the thickness of a specific adhesive layer, since it can be made to be the same as that of the adhesive layer used for a general display apparatus, description here is abbreviate | omitted.

  When the display panel is bonded, it may be bonded to a desired position by using an alignment mark attached to the surfaces of the display panel and the display device substrate. Note that the alignment marks can be the same as those generally used in the manufacturing process of the display device, and thus description thereof is omitted here.

The display panel is typically a liquid crystal display panel or an electroluminescent (EL) panel, but may be an electronic paper panel, a display device using a cathode ray tube, or various known display panels.
The above-described display panel can be the same as that used in a general display device, and thus a specific description thereof is omitted here.

5. Other Steps The manufacturing method of the display device according to this aspect may include other steps as necessary in addition to the steps described above. In addition, about another process, since the process etc. which are used for the manufacturing method of a general display apparatus are mentioned, description here is abbreviate | omitted.

B. Fourth aspect A method for producing a display device according to this aspect is selected from the group consisting of a structure containing an aromatic ring and represented by the general formula (1) and the general formula (3) on a support substrate. A preparation step of preparing a substrate for display device containing polyimide having at least one kind of structure, a functional layer formation step of forming a functional layer on the substrate for display device after the preparation step, and the function A manufacturing method comprising: a bonding step of bonding a display panel to a surface on which the functional layer is formed after the layer forming step; and a peeling step of peeling the support substrate after the bonding step. It is.
Note that the preparation step and the functional layer formation step are the same as those in the third aspect, and thus description thereof is omitted here. Hereinafter, other steps in the method for manufacturing the display device of this aspect will be described.

1. Bonding step The bonding step in this embodiment is a step of bonding the display panel to the surface on which the functional layer is formed after the functional layer forming step.

The method of bonding the display panel to the surface on which the functional layer is formed can be the same as the bonding method used in the general manufacturing method of a display device. For example, both are bonded via an adhesive layer. The method of crimping is mentioned.
In addition, since it is the same as that of the said 3rd aspect about an adhesive layer, the bonding method, and a display panel, description here is abbreviate | omitted.

2. Peeling process The peeling process in this aspect is a process of peeling a support base material after a bonding process.
In addition, since it is the same as that of the said 3rd aspect about the peeling method of a support base material, description here is abbreviate | omitted.

3. Other Steps The manufacturing method of the display device according to this aspect may include other steps as necessary in addition to the steps described above. In addition, about another process, since the process etc. which are used for the manufacturing method of a general display apparatus are mentioned, description here is abbreviate | omitted.

III. Flexible display device The flexible display device of the present invention includes an aromatic ring and has at least one structure selected from the group consisting of the structures represented by the general formula (1) and the general formula (3). A substrate for display device containing polyimide, a functional layer disposed on the substrate for display device, and a surface opposite to the functional layer of the substrate for display device or disposed on the functional layer And a display panel.

  FIG. 8A is a schematic sectional view showing an example of the flexible display device of the present invention. As shown in FIG. 8A, a flexible display device 10A includes a display device substrate 3 containing polyimide having a predetermined structure, a functional layer 4 formed on the display device substrate 3, and a display. It has the display panel 11 arrange | positioned through the adhesive layer 12 in the surface on the opposite side to the functional layer 4 of the base material 3 for apparatuses.

  FIG. 8B is a schematic cross-sectional view showing another example of the flexible display device of the present invention. As shown in FIG. 8B, the flexible display device 10A includes a display device substrate 3 containing polyimide having a predetermined structure, a functional layer 4 formed on the display device substrate 3, and a function. The display panel 11 is disposed on the layer 4 via the pressure-sensitive adhesive layer 12.

  According to the present invention, as described in the above “I. Laminate”, the substrate for display device containing polyimide having a predetermined structure is used to manufacture the flexible display device of the present invention. Even through the heating step, it is possible to suppress changes in the optical characteristics of the display device substrate, in particular, the yellowness YI value and the total light transmittance. Therefore, good display quality can be obtained.

  Since each configuration of the flexible display device has been described in detail in “I. Laminate” and “II. Manufacturing method of display device”, description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

[Example 1]
(Preparation of polyimide precursor solution)
A 500 mL separable flask was charged with 364 g of dehydrated N, N-dimethylacetamide (DMAC) and 38.4 g of 2,2′-bis (trifluoromethyl) benzidine (TFMB), and a mechanical stirrer at 25 ° C. Stir with. Thereto, 52.9 g of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) was gradually added to synthesize a polyimide precursor solution A.

(Formation of polyimide film)
On the glass substrate, the polyimide precursor solution A was apply | coated using the spin coat method. Then, it was temporarily dried for 3 minutes on a 100 degreeC hotplate, and the polyimide precursor coating film was formed. Next, the temperature was increased to 350 ° C. in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min, held at 350 ° C. for 1 hour, and then cooled to room temperature to form a 10 μm thick polyimide film. Thereby, the laminated body in which the polyimide film was formed on the glass base material was obtained.

[Example 2]
In the formation of the polyimide film of Example 1, a polyimide film was formed in the same manner as in Example 1 except that heat treatment was performed in an air atmosphere to obtain a laminate.

[Comparative Example 1]
A tetracarboxylic dianhydride containing an aromatic ring, which does not correspond to the tetracarboxylic acid residue of R ⁵ in the above formula (3), and a diamine containing an aromatic ring there are, to prepare a polyimide precursor solution B prepared using a diamine does not correspond to the diamine residue of R ² in the formula (1).
In Example 1, a polyimide film was formed in the same manner as in Example 1 except that the polyimide precursor solution B was used instead of the polyimide precursor solution A to obtain a laminate.

[Comparative Example 2]
In the formation of the polyimide film of Comparative Example 1, a polyimide film was formed in the same manner as in Comparative Example 1 except that heat treatment was performed in an air atmosphere to obtain a laminate.

[Evaluation]
About the laminated body of an Example and a comparative example, the polyimide film was peeled from the glass base material, and the total light transmittance, haze value, YI value, birefringence (Rth), and linear thermal expansion coefficient of the polyimide film were measured. The results are shown in Table 1.
Moreover, the qualitative analysis of a polyimide film is also performed, and the polyimide film of Examples 1 and 2 contains an aromatic ring, and consists of the group which consists of a structure represented by the said General formula (1) and the said General formula (3). It was confirmed to contain a polyimide having at least one selected structure.

(Total light transmittance)
Based on JIS K7361-1, it measured with the haze meter (HM150 by Murakami Color Research Laboratory). Moreover, the conversion value in thickness 10micrometer was calculated | required by the Lambert Beer law as follows.
Specifically, according to Lambert Beer's law, the transmittance T is
Log ₁₀ (1 / T) = kcb
(K = constant specific to substance, c = concentration, b = optical path length).
For the transmittance of the film, so even if the film thickness is changed density is also constant c assuming a constant, the above formula, Log 10 using constants f _{(1 / T)} = fb
(F = kc). Here, if the transmittance at a certain film thickness is known, a specific constant f of each substance can be obtained. Accordingly, the transmittance at a desired film thickness can be obtained by substituting a constant specific to f and a target film thickness into b using the equation of T = 1/10 ^{f · b} .

(Haze value)
The haze value was measured by a method based on JIS K7136 using a haze meter (HM150, manufactured by Murakami Color Research Laboratory).

(YI value)
The YI value was determined in accordance with JIS K7105-1981, using an ultraviolet-visible near-infrared spectrophotometer (JASCO Corp. V-7100), using a C light source conforming to JIS Z8701-1999 as a light source with a field of view of 2 degrees. Determined by the method.

(Birefringence)
Using a phase difference measuring device (manufactured by Oji Scientific Instruments, product name “KOBRA-WR”), the thickness direction retardation value (Rth) of the polyimide film was measured with light at 23 ° C. and a wavelength of 590 nm. For the thickness direction retardation value (Rth), a phase difference value at 0 ° incidence and a phase difference value at an incidence angle of 40 ° were measured, and a thickness direction retardation value Rth was calculated from these retardation values. The retardation value at an oblique incidence of 40 degrees was measured by making light having a wavelength of 590 nm incident on the polyimide film from a direction inclined by 40 degrees from the normal line of the polyimide film.
The birefringence of the polyimide film was determined by substituting it into the formula: Rth / d (polyimide film thickness (nm)).

(Linear thermal expansion coefficient)
The linear thermal expansion coefficient was determined by using a thermomechanical analyzer (for example, Thermo Plus TMA8310 (manufactured by Rigaku Corporation)) at a heating rate of 10 ° C./min and a tensile load of 1 g so that the load per cross-sectional area of the evaluation sample was the same. / 25000 μm ² , the dimensional change from 25 ° C. to 400 ° C. was measured. The linear thermal expansion coefficient was obtained by calculating the linear thermal expansion coefficient in the range of 100 ° C. to 150 ° C. when the temperature was raised. The sample width was 5 mm and the distance between chucks was 15 mm.

(Qualitative analysis)
Pretreatment was performed as follows, the polyimide film was decomposed with supercritical methanol to obtain a polyimide decomposition product, and the entire qualitative analysis was performed on the polyimide decomposition product using GC-MS.
<Pretreatment>
(I) The base material for display device is shaved with a scalpel, and a few μg (about 1/10 in internal volume) of the shaved base material for display device is put into a glass tube (Glass capsule b: made by Frontier LAB).
(Ii) 15 μL of methanol is injected into the glass tube containing the sample with a microsyringe.
(Iii) A glass tube containing a base material sample for display device and methanol is sealed with a burner.
(Iv) Place the sealed glass tube in an electric furnace at 280 ° C. and leave it for 10 hours.
(V) Remove the glass tube from the electric furnace and open it.
(Vi) Collect all the liquid in the glass tube with a micro syringe and inject it into the cup for GCMS.
<Gas chromatograph mass spectrometry>
Equipment used: GCMS: GCMS2020 (manufactured by Shimadzu Corporation)
Electric furnace: W shot pyrolyzer (manufactured by FLONTIER LAB)
Electric furnace temperature: 320 ° C
Inlet temperature: 320 ° C
Oven conditions: Hold at 50 ° C. for 5 minutes −Raise at 10 ° C./minute − Hold at 320 ° C. for 15 minutes Interface temperature: 320 ° C.
Ion source temperature: 260 ° C
Measurement mass range: m / z: 40-650
Column: UA (Ultra Alloy) -5 Length: 30 m Inner diameter: 0.25 mm Film thickness: 0.25 μm

  In the polyimide films of Examples 1 and 2, the increase in YI value was small even when the heat treatment was performed in an air atmosphere as compared to the case where the heat treatment was performed in a nitrogen atmosphere. On the other hand, in the polyimide films of Comparative Examples 1 and 2, when the heat treatment was performed in an air atmosphere, the YI value was greatly increased as compared to the case where the heat treatment was performed in a nitrogen atmosphere. Thereby, in the case of the polyimide film containing the polyimide having a predetermined structure, it has been clarified that the change in the YI value is small even after the heat treatment in the air atmosphere.

[Example 3]
A polyimide film was formed using the polyimide precursor solution A of Example 1. That is, the polyimide precursor solution A was applied onto a glass substrate using a spin coat method. Then, it was temporarily dried for 3 minutes on a 100 degreeC hotplate, and the polyimide precursor coating film was formed. Next, the temperature was increased to 350 ° C. in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min, held at 350 ° C. for 1 hour, and then cooled to room temperature to form a 10 μm thick polyimide film. Thereby, the laminated body in which the polyimide film was formed on the glass base material was obtained.
Next, the laminate was fired at 230 ° C. in the air atmosphere for 30 minutes to 120 minutes. The firing conditions assume the conditions for forming the black matrix and the colored layer of the color filter.
About the laminated body before baking and after baking, the polyimide film was peeled from the glass base material, and the YI value of the polyimide film was measured. The results are shown in Table 2.

[Comparative Example 3]
A polyimide film was formed using the polyimide precursor solution B of Comparative Example 1. That is, the polyimide precursor solution B was applied onto a glass substrate using a spin coat method. Then, it was temporarily dried for 3 minutes on a 100 degreeC hotplate, and the polyimide precursor coating film was formed. Next, the temperature was increased to 350 ° C. in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min, held at 350 ° C. for 1 hour, and then cooled to room temperature to form a 10 μm thick polyimide film. Thereby, the laminated body in which the polyimide film was formed on the glass base material was obtained.
Next, the laminate was baked in a nitrogen atmosphere at 230 ° C. for 30 minutes to 120 minutes.
About the laminated body before baking and after baking, the polyimide film was peeled from the glass base material, and the YI value of the polyimide film was measured. The results are shown in Table 2.

  In the polyimide film of Example 3, the increase in YI value was small even after the thermal history after the polyimide film was formed. On the other hand, in the polyimide film of Comparative Example 3, the YI value greatly increased due to the thermal history after the polyimide film was formed even in a nitrogen atmosphere. Thereby, in the case of the polyimide film containing the polyimide which has a predetermined structure, it became clear that even if it passes through the thermal history after polyimide film formation, there is little change of YI value.

[Example 4]
(Preparation of polyimide precursor solution)
A 500 mL separable flask was charged with 364 g of dehydrated N, N-dimethylacetamide (DMAC) and 38.4 g of 2,2′-bis (trifluoromethyl) benzidine (TFMB), and a mechanical stirrer at 25 ° C. Stir with. Thereto, 52.9 g of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) was gradually added to synthesize a polyimide precursor solution.

(Formation of polyimide film)
On the glass substrate, the polyimide precursor solution A was apply | coated using the spin coat method. Then, it was temporarily dried for 3 minutes on a 100 degreeC hotplate, and the polyimide precursor coating film was formed. Next, the temperature was increased to 350 ° C. in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min, held at 350 ° C. for 1 hour, and then cooled to room temperature to form a 10 μm thick polyimide film. Thereby, the laminated body in which the polyimide film was formed on the glass base material was obtained.

[Examples 5 to 12]
(Preparation of polyimide precursor solution)
In Example 4, instead of 2,2′-bis (trifluoromethyl) benzidine (TFMB) and 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), the molar ratios shown in the following Table 3 were used. A polyimide precursor solution was synthesized in the same manner as in Example 4 except that a tetracarboxylic dianhydride component and a diamine component were used.

The abbreviations in Table 3 are as follows.
6FDA: 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride aBPDA: 2,3 ′, 3,4′-biphenyltetracarboxylic dianhydride sBPDA: 3,3 ′, 4,4′-biphenyl Tetracarboxylic acid dianhydride PMDA: pyromellitic dianhydride TFMB: 2,2′-bis (trifluoromethyl) benzidine DDS: 4,4′-diaminodiphenyl sulfone PPD: paraphenylenediamine

(Formation of polyimide film)
In the same manner as in Example 4, a polyimide film was formed to obtain a laminate.

[Evaluation]
About the laminated body of Examples 4-12, the polyimide film was peeled from the glass base material similarly to Example 1, and the total light transmittance, haze value, and YI value of the polyimide film were measured. In addition, about the polyimide film of Example 4, it was set as the average value of 5 samples.

  Moreover, the qualitative analysis of a polyimide film is performed similarly to Example 1, and the polyimide film of Examples 4-12 contains an aromatic ring, and is represented by the said General formula (1) and the said General formula (3). It was confirmed that it contains a polyimide having at least one structure selected from the group consisting of the following structures.

  The polyimide films of Examples 4 to 12 all had high transparency. Furthermore, the YI value of the polyimide film of Example 4 was also low.

[Example 13]
(Preparation of polyimide precursor solution)
A 500 ml separable flask was charged with 225.0 g of dehydrated N-methylpyrrolidone and 24.4 g of 2,2′-bis (trifluoromethyl) benzidine (TFMB), and stirred at 25 ° C. with a mechanical stirrer. . Thereto, 31.8 g of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) was gradually added to synthesize a polyimide precursor solution.

(Formation of polyimide film)
The polyimide precursor solution is applied onto a glass substrate, dried in a circulating oven at 120 ° C. for 10 minutes to form a polyimide precursor resin coating film, and then the resin coating film is heated at a heating rate of 10 ° C./min in a nitrogen atmosphere. The temperature was raised to 350 ° C. below (oxygen concentration of 100 ppm or less), held at 350 ° C. for 1 hour, and then cooled to room temperature to form a 10 μm thick polyimide film.

(Formation of stress relaxation layer)
The glass substrate on which the polyimide film was formed was held in a holder in a film forming chamber of a sputtering apparatus manufactured by Canon Anelva. While this holder was rotated about an axis perpendicular to the mold holding surface, silicon oxide was deposited on the polyimide layer under the following sputtering conditions to form a stress relaxation layer.
<Sputtering conditions>
-Film formation target: SiO ₂
・ Power value: 900W
-Reaction gas: Ar (flow rate = 30.0 sccm)
O ₂ (flow rate = 10.0 sccm)
・ Film thickness: 300nm

(Formation of barrier layer)
First, a copolymer resin solution was prepared as follows. That is, 63 parts by weight of methyl methacrylate (MMA), 12 parts by weight of acrylic acid (AA), 6 parts by weight of 2-hydroxyethyl methacrylate (HEMA), and 88 parts by weight of diethylene glycol dimethyl ether (DMDG) in the polymerization tank. After the parts were charged, stirred and dissolved, 7 parts by weight of 2,2′-azobis (2-methylbutyronitrile) was added and dissolved uniformly. Then, it stirred at 85 degreeC under nitrogen stream for 2 hours, and also was made to react at 100 degreeC for 1 hour. Further, 7 parts by weight of glycidyl methacrylate (GMA), 0.4 parts by weight of triethylamine, and 0.2 parts by weight of hydroquinone were added to the obtained solution, and the mixture was stirred at 100 ° C. for 5 hours to obtain a copolymer resin solution ( A solid content of 50%) was obtained.

Next, the following materials were stirred and mixed at room temperature to prepare an ultraviolet curable resin composition.
<Composition of UV curable resin composition>
-Copolymer resin solution (solid content 50%) ... 16 parts by weight-Dipentaerythritol pentaacrylate (Sartomer SR399) ... 24 parts by weight-Orthocresol novolac type epoxy resin (Oilized Shell Epoxy Epicoat 180S70) ... 4 weights Parts 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one ... 4 parts by weight diethylene glycol dimethyl ether 52 parts by weight

  This ultraviolet curable resin composition was applied onto the stress relaxation layer and cured by irradiating with ultraviolet rays to form a 1.0 μm thick barrier layer.

(Formation of black matrix and colored part)
Next, a black matrix and a colored portion were formed on the barrier layer. In forming the black matrix and the colored portion, first, a lattice-shaped black matrix was formed by a photolithography method using a resin composition for a light shielding layer having the following composition. The black matrix had a thickness of about 1 μm, a line width of 10 μm, and a red-colored portion, a green-colored portion, and a blue-colored portion having repeating stripe-shaped openings with a pitch of 75 μm.

In the preparation of the light shielding layer resin composition, the following components were first mixed and sufficiently dispersed in a sand mill to prepare a black pigment dispersion.
<Composition of black pigment dispersion>
・ Black pigment: 23 parts by weight ・ Polymer dispersing agent (Bicchemy Japan Co., Ltd. Disperbyk 111): 2 parts by weight ・ Solvent (diethylene glycol dimethyl ether): 75 parts by weight

Next, the following amounts of components were sufficiently mixed to obtain a resin composition for a light shielding layer.
<Composition of resin composition for light shielding layer>
-Black pigment dispersion liquid-61 parts by weight-UV curable resin composition-20 parts by weight-Diethylene glycol dimethyl ether-30 parts by weight

  Next, using a resin composition for red colored portion, a resin composition for green colored portion, and a resin composition for blue colored portion having the following composition, the black matrix is coated by a photolithography method so that the coating thickness becomes 2.0 μm. A relief-type pattern was provided in the opening to form a red colored portion, a green colored portion, and a blue colored portion.

<Resin composition for red colored portion>
・ C. I. Pigment Red 254 ... 7 parts by weight-Polysulfonic acid type polymer dispersant ... 3 parts by weight-UV curing resin composition described above ... 23 parts by weight--3-methoxybutyl acetate ... 67 parts by weight

<Green colored part resin composition>
・ C. I. Pigment Green 58: 7 parts by weight C.I. I. Pigment Yellow 138 1 part by weight, polysulfonic acid type polymer dispersant 3 parts by weight UV curable resin composition 22 parts by weight, 3-methoxybutyl acetate 67 parts by weight

<Resin composition for blue colored layer>
・ C. I. Pigment Blue 1 5 parts by weight, polysulfonic acid type polymer dispersant 3 parts by weight UV curable resin composition 25 parts by weight, 3-methoxybutyl acetate 67 parts by weight

(Peeling process)
About the laminated body obtained as mentioned above, the member for display apparatuses was produced by peeling from a glass substrate.

[Example 14]
(Preparation of polyimide precursor solution)
In Example 13, instead of 2,2′-bis (trifluoromethyl) benzidine (TFMB), an equimolar amount of 4,4′-diaminodiphenyl sulfone (DDS) was used. A polyimide precursor solution was synthesized in the same manner as described above.

(Preparation of display device members)
A display device member was produced in the same manner as in Example 13 except that the polyimide precursor solution was used.

[Example 15]
(Preparation of polyimide precursor solution)
In Example 13, instead of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), an equimolar amount of 2,3,3 ′, 4′-biphenyltetracarboxylic diacid anhydride was used. A polyimide precursor solution was synthesized in the same manner as in Example 13 except that the product (aBPDA) was used.

(Preparation of display device members)
A display device member was produced in the same manner as in Example 13 except that the polyimide precursor solution was used.

[Example 16]
(Preparation of polyimide precursor solution)
In Example 13, instead of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2′-bis (trifluoromethyl) benzidine (TFMB), an equimolar amount of 2 , 3,3 ′, 4′-biphenyltetracarboxylic dianhydride (aBPDA) and 4,4′-diaminodiphenylsulfone (DDS) were used in the same manner as in Example 13 to obtain a polyimide precursor. A body solution was synthesized.

(Preparation of display device members)
A display device member was produced in the same manner as in Example 13 except that the polyimide precursor solution was used.

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Support base material 3 ... Base material for display apparatuses 4 ... Functional layer 5 ... Adhesive layer 10 ... Display apparatus 10A ... Flexible display apparatus 11 ... Display panel 12 ... Adhesive layer 21 ... Stress relaxation layer 22, 23 ... barrier layer

Claims (14)

A support substrate;
A polyimide that is disposed on the support substrate, includes an aromatic ring, and has at least one structure selected from the group consisting of structures represented by the following general formula (1) and the following general formula (3): A laminate having a display device substrate.

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.)   2. The laminate according to claim 1, wherein the thickness of the substrate for a display device is in a range of 3 μm to 12 μm.   The laminate according to claim 1, further comprising an adhesive layer disposed between the support substrate and the display device substrate.   It has a functional layer arrange | positioned on the said base material for display apparatuses, The laminated body in any one of Claim 1 to 3 characterized by the above-mentioned. The polyimide has a structure represented by the general formula (3), and in the general formula (3), R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ Represents a 2,2′-bis (trifluoromethyl) benzidine residue,
The laminate according to claim 4, wherein the functional layer includes a stress relaxation layer and two or more barrier layers in order from the display device substrate side. The polyimide has a structure represented by the general formula (3), and in the general formula (3), R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ Represents a 4,4′-diaminodiphenylsulfone residue;
The laminate according to claim 4, wherein the functional layer includes a stress relaxation layer and two or more barrier layers in order from the display device substrate side. The polyimide has a structure represented by the general formula (3), and in the general formula (3), R ⁵ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ⁶ Represents a paraphenylenediamine residue,
As the functional layer, it has two or more barrier layers,
The laminate according to claim 4, wherein the functional layer includes a stress relaxation layer and two or more barrier layers in order from the display device substrate side. The polyimide has a structure represented by the general formula (1). In the general formula (1), R ¹ represents a 2,3 ′, 3,4′-biphenyltetracarboxylic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue;
The laminate according to claim 4, wherein the functional layer includes a stress relaxation layer and two or more barrier layers in order from the display device substrate side. The polyimide has a first structure represented by the general formula (1) and a second structure represented by the general formula (1),
In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents 2,2′-bis (trifluoromethyl). A structure representing a benzidine residue;
In the general formula (1), the second structure is a structure in which R ¹ represents a pyromellitic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue.
The content of the first structure is 90 mol% or more based on the total of the structures represented by the general formula (1) and the general formula (3), and the content of the second structure is The amount is 10 mol% or less based on the total of the structures represented by the general formula (1) and the general formula (3), according to any one of claims 1 to 4. Laminated body. The polyimide has a first structure represented by the general formula (1) and a second structure represented by the general formula (1),
In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents 2,2′-bis (trifluoromethyl). A structure representing a benzidine residue;
In the general formula (1), the second structure is a structure in which R ¹ represents a pyromellitic acid residue, and R ² represents a 2,2′-bis (trifluoromethyl) benzidine residue.
The content of the first structure is 50% or more and 95 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3), Content is 5 mol% or more and 50 mol% or less with respect to the sum total of the structure represented by the said General formula (1) and the said General formula (3). The laminated body in any one of to. The polyimide has a first structure represented by the general formula (1) and a third structure represented by the general formula (1),
In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents 2,2′-bis (trifluoromethyl). A structure representing a benzidine residue;
Said third structure is in the general formula (1), ^{R 1} is 3,3 ', represents a 4,4'-biphenyl tetracarboxylic acid residue, ^{R 2} is 2,2-bis (trifluoromethyl ) Is a structure representing a benzidine residue,
The content of the first structure is 90 mol% or more based on the total of the structures represented by the general formula (1) and the general formula (3), and the content of the third structure is The amount is 10 mol% or less based on the total of the structures represented by the general formula (1) and the general formula (3), according to any one of claims 1 to 4. Laminated body. The polyimide has a first structure represented by the general formula (1) and a third structure represented by the general formula (1),
In the general formula (1), R ¹ represents a 4,4 ′-(hexafluoroisopropylidene) diphthalic acid residue, and R ² represents 2,2′-bis (trifluoromethyl). A structure representing a benzidine residue;
Said third structure is in the general formula (1), ^{R 1} is 3,3 ', represents a 4,4'-biphenyl tetracarboxylic acid residue, ^{R 2} is 2,2-bis (trifluoromethyl ) Is a structure representing a benzidine residue,
The content of the first structure is 30 mol% or more and 95 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3), and the third structure The content of is 5 mol% or more and 70 mol% or less with respect to the total of the structures represented by the general formula (1) and the general formula (3). The laminate according to any one of 4 to 4. A substrate for a display device, a functional layer formed on the substrate for a display device, and a display panel disposed on the surface of the substrate for the display device opposite to the functional layer or on the functional layer; A method of manufacturing a display device having
The above-mentioned polyimide containing at least one structure selected from the group consisting of the structure represented by the following general formula (1) and the following general formula (3), which contains an aromatic ring on the support substrate A preparation step of preparing a substrate for a display device;
After the preparation step, a functional layer forming step of forming the functional layer on the display device substrate;
And a peeling step of peeling off the support substrate after the functional layer forming step.

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.) A base material for a display device comprising a polyimide having an aromatic ring and having at least one structure selected from the group consisting of structures represented by the following general formula (1) and the following general formula (3):
A functional layer disposed on the substrate for the display device;
A flexible display device comprising: a surface of the substrate for display device opposite to the functional layer, or a display panel disposed on the functional layer.

(In the general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 ′. -Represents at least one divalent group selected from the group consisting of a diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, and a divalent group represented by the following general formula (2). n represents the number of repeating units and is 1 or more.)

(In General Formula (2), R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

(In the general formula (3), R ⁵ represents a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3 ′, 4′-tetracarboxylic acid residue, and 4,4 ′. -(Hexafluoroisopropylidene) at least one tetravalent group selected from the group consisting of diphthalic acid residues, R ⁶ represents a divalent group which is a diamine residue, n 'represents the number of repeating units, 1 or more.)

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