TW201412552A - Transparent polyimido laminate, method for producing the same, optical film, method for producing flexible device, touch panel display, liquid crystal display and organic EL display - Google Patents

Abstract

A method for producing the transparent polyimido laminate having the support substrate and the transparent polyimido layer laminated on the support substrate is provided. The method includes: (a) coating a solution containing a polyimido precursor on the support substrate, wherein the solution containing the polyimido precursor contains a polyimido precursor obtained by reacting a tetracarboxylic acid component and a diamine component, and a solvent; and (b) heating a polyimido precursor film containing the coating of the solution containing the polyimido precursor at a temperature higher than or equal to the glass transformation temperature of the transparent polyimido layer, wherein the glass transformation temperature of the transparent polyimido layer is 260 DEG C or more, a transparency of all light is 80% or more, a haze value is 5% or less, an absolute value of b value in the L*a*b color system is 5 or less, the in-plane phase difference is 10 nm or less, and the peeling strength when the transparent polyimido layer is peeled from the support substrate is 0.005 to 0.20 kN/m.

Description

Transparent polyimine laminate and manufacturing method thereof

The present invention relates to a transparent polyimine laminate and a method of producing the same.

Since the polyimide resin has excellent heat resistance and mechanical properties, a polyimide film is applied to a substrate or the like of various flexible printed wiring boards. One of the methods for producing the polyimide film is a casting method. The casting method is the following method: (i) coating a polyimide precursor on a support substrate, (ii) imidizing the polyimide precursor by heat treatment, (iii) self-supporting substrate The polyimine film was peeled off to obtain a polyimide film. The support substrate is usually a glass substrate, but it has been proposed to set the support substrate to a metal plate or a non-thermoplastic resin (Patent Documents 1 to 3).

Conventionally, inorganic glass as a transparent material is used for a panel substrate or the like in a display such as a liquid crystal display element or an organic electroluminescence (EL) display element. However, the inorganic glass has a high specific gravity (weight) and thus has low bendability or impact resistance. Therefore, for substrates requiring flexible liquid crystal display elements or organic EL display elements, polyethylene terephthalate (PET) or polyethylene naphthalate is widely used. (Polyethylene naphthalate, PEN) film. However, the heat resistance of these films is low, and the temperature at which various elements are formed is limited. Therefore, a substrate having higher heat resistance is sought.

On the other hand, a panel substrate in which a polyimide film excellent in light weight, impact resistance, workability, and flexibility is applied to a flexible element has been studied. However, the polyimide film obtained by the techniques of Patent Documents 1 to 3 described above has low light transmittance and is difficult to be applied to a panel substrate of a flexible display. On the other hand, a polyimide film obtained by reacting bis(trifluoromethyl)benzidine with a tetracarboxylic acid component has been proposed as a film having high transparency and heat resistance (Patent Document 4).

Prior technical literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2011-56825

Patent Document 2: Japanese Patent Laid-Open Publication No. 2004-322441

Patent Document 3: Japanese Patent Laid-Open No. 11-10664

Patent Document 4: Japanese Patent Laid-Open Publication No. 2012-40836

However, the polyimide film of Patent Document 4 produced by the casting method is difficult to peel off from the support substrate (glass substrate), and in order to peel off the polyimide film, the support substrate and the polyimide film must be impregnated. The laser light is irradiated in water or at the interface of the support substrate and the polyimide film.

The present invention has been made in view of such circumstances. An object of the present invention is to provide a transparent polyimine laminate and a method for producing the same, the above transparent polyimide layer laminate A transparent polyimide layer having high light transmittance, small in-plane retardation, and easy peeling on a self-supporting substrate.

First, the present invention relates to a method for producing a transparent polyimide polyimide laminate.

[1] A method for producing a transparent polyimide polyimide laminate, which is a method for producing a transparent polyimide polyimide laminate comprising a support substrate and a transparent polyimide layer laminated on the support substrate, The method includes the steps of: a) applying a solution containing a polyimide precursor to the support substrate, wherein the solution containing the polyimide precursor contains a polymerization reaction between a tetracarboxylic acid component and a diamine component. a ruthenium imine precursor and a solvent; and b) a polyimide film precursor comprising a coating film of the above polyimine-containing precursor solution at a temperature above the glass transition temperature of the transparent polyimide layer a step of heating the film; and the glass transition temperature of the transparent polyimide layer is 260 ° C or higher, the total light transmittance is 80% or more, and the haze value is 5% or less, b in the L*a*b color system The absolute value of the value is 5 or less, and the in-plane retardation is 10 nm or less, and the peel strength when the transparent polyimide layer is peeled off from the support substrate is 0.005 kN/m to 0.20 kN/m.

[2] The method for producing a transparent polyimine laminate according to [1], wherein the support substrate is a flexible substrate.

[3] The method for producing a transparent polyimine laminate according to [1] or [2], wherein the solution containing the polyimide precursor further contains a release agent.

[4] The method for producing a transparent polyimine laminate according to any one of [1] to [3] wherein the atmosphere is in a temperature range exceeding 200 ° C in the above step b) The oxygen concentration of (atomosphere) is set to 5 vol% or less.

[5] The method for producing a transparent polyimine laminate according to any one of [1] to [3] wherein the atmosphere is decompressed in a temperature range of more than 200 ° C in the step b).

[6] The method for producing a transparent polyimine laminate according to any one of [1] to [5] wherein the step b) is to raise the temperature from 150 ° C or lower to more than 200 ° C. The step of heating the quinone imine precursor film, and setting the average temperature increase rate in the temperature range of 150 ° C to 200 ° C in the above step b) to 0.25 ° C / min to 50 ° C / min.

The method for producing a transparent polyimine laminate according to any one of the above aspects, wherein the polyimine precursor is a tetracarboxylic acid component (A) and a diamine component. (B) a compound obtained by the reaction, wherein the tetracarboxylic acid component (A) contains one or more kinds of tetracarboxylic dianhydride represented by the following formula (a), and the diamine component (B) is selected from the group consisting of One or more diamines in the group consisting of the compounds represented by the formulae (b-1) to (b-3),

(In the formula (a), R ¹ represents a tetravalent group having 4 to 27 carbon atoms, and represents an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensation. a polycyclic aromatic group, or a non-condensed polycyclic aliphatic group represented by a cyclic aliphatic group directly or by a crosslinker, or an aromatic group directly or by a crosslinker Non-condensed polycyclic aromatic group),

[8] The method for producing a transparent polyimine laminate according to [7], wherein the polyimine precursor has a repeating unit represented by the following formula (1), and is in the formula (1) The 1,4-bismethylenecyclohexane skeleton (X) includes a trans form represented by the formula (X1) and a cis form represented by the formula (X2), and a content ratio of the trans form to the cis form ( Trans-body + cis-form = 100%) is 60% ≦ trans-body ≦ 100%, 0% ≦ cis-body ≦ 40%,

(In the formula (1), R ¹⁰ represents a tetravalent group having 4 to 27 carbon atoms, and represents an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensation. a polycyclic aromatic group, or a non-condensed polycyclic aliphatic group represented by a cyclic aliphatic group directly or by a crosslinker, or an aromatic group directly or by a crosslinker Non-condensed polycyclic aromatic groups).

[9] The method for producing a transparent polyimine laminate according to any one of [1] to [6] wherein the polyamidene precursor is a polyphthalamide block and a polyimine. a block poly-pyridinium imide, the poly-proline block is composed of a repeating structural unit represented by the following general formula (G), and the polyimine block is represented by the following formula (H) consisting of the repeated structural units represented,

(In the general formula (G) and the general formula (H), R ⁶ and R ⁸ each independently represent a tetravalent group having 4 to 27 carbon atoms, and represent an aliphatic group, a monocyclic aliphatic group, and a condensed polycyclic fat. a group-based, monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group represented by a cyclic aliphatic group directly or by a crosslinker, or an aromatic a non-condensed polycyclic aromatic group which is bonded to each other directly or by a crosslinker; in the formula (H), R ⁷ is a divalent group having a carbon number of 4 to 51, and is an aliphatic group or a single ring. An aliphatic group (excluding 1,4-cyclohexylene), a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensed polycyclic aromatic group, or a cyclic aliphatic group directly or borrowed A non-condensed polycyclic aliphatic group which is linked to each other by a crosslinker, or a non-condensed polycyclic aromatic group which is an aromatic group directly or by a crosslinker.

[10] The method for producing a transparent polyimine laminate according to any one of [1] to [9] wherein the step a) is to apply the above-mentioned support to the support substrate which is wound from a roll. a step of a solution of the polyimide precursor, and the above step b) comprises the step of winding the transparent polyimide laminate onto the roll after heating of the polyimide film of the polyimide.

Second, the present invention relates to the following transparent polyimide laminates or optical films.

[11] A transparent polyimine laminate which is obtained by the production method according to any one of the above [1] to [9].

[12] An optical film obtained by peeling a transparent polyimide layer from a support substrate of the transparent polyimide laminate according to [11] above.

Thirdly, the present invention relates to a method for producing a transparent polyimide film, a method for producing a flexible member, and various display devices.

[13] A method for producing a transparent polyimide film, comprising: peeling a transparent polyimide layer from a support substrate of the transparent polyimide laminate according to the above [11], thereby obtaining a transparent polyimide The step of the amine film.

[14] A method for producing a flexible member, comprising: forming a member on the transparent polyimide layer of the transparent polyimide layer according to [11]; and forming the member The step of peeling off the transparent polyimide layer from the support substrate.

[15] A method for producing a flexible member, comprising the step of forming an element on a transparent polyimide film obtained by the production method according to [11] above.

[16] A touch panel display obtained by the method for producing a flexible element according to [14] or [15] above.

[17] A liquid crystal display obtained by the method for producing a flexible member according to [14] or [15] above.

[18] An organic EL display obtained by the method for producing a flexible member according to [14] or [15] above.

According to the present invention, a transparent polyimide polyimide laminate having a transparent polyimide layer which can be easily peeled off from a support substrate, has high light transmittance, and has a small in-plane retardation can be obtained.

1‧‧‧ Polyimine precursor film

1'‧‧‧Transparent Polyimine Layer

10‧‧‧heating furnace

11‧‧‧Support substrate

12‧‧‧Transparent Polyimine Laminates

13‧‧‧ components

14‧‧‧Other substrates

20‧‧‧ Coating device

21‧‧‧Ring belt

30‧‧‧ Roll body

Fig. 1 is a side view showing an example of a manufacturing apparatus for producing a long transparent polyimide laminate by the production method of the present invention.

2 is a schematic cross-sectional view showing an example of a method of producing a flexible member using the transparent polyimide laminate of the present invention.

Fig. 3 is a schematic cross-sectional view showing another example of a method for producing a flexible member using the transparent polyimide laminate of the present invention.

4 is a schematic cross-sectional view showing another example of a method of producing a flexible member using the transparent polyimide laminate of the present invention.

A. Method for producing transparent polyimine laminate

In the manufacturing method of the present invention, a transparent polyimine laminate is produced, the transparent polyimide laminate layer comprising a support substrate and a transparent polyimide layer, and the transparent polyimide layer is peeled off from the support substrate The peel strength at the time is 0.005 kN/m to 0.20 kN/m, preferably 0.01 kN/m to 0.15 kN/m, and more preferably 0.05 kN/m to 0.10 kN/m. The peel strength is a value measured in accordance with Japanese Industrial Standards (JIS) C-6471 (peeling angle: 90°).

As described above, when the polyimide film is formed on the support substrate by a usual casting method, it is difficult to separate the obtained polyimide film from the support substrate, and it is necessary to impregnate the polyimide film and the support substrate. The laser is irradiated to the interface in the water or at the interface between the support substrate and the polyimide film to perform the peeling. Further, if the film is peeled off from the support substrate after the element is formed on the polyimide film, stress may be applied to the element, or water may adhere to the element to damage the element.

On the other hand, in the transparent polyimine laminate produced by the production method of the present invention, the peeling strength of the transparent polyimide layer and the support substrate is small. Therefore, even after the element is formed on the transparent polyimide layer, the transparent polyimide layer can be easily peeled off from the support substrate.

The manufacturing method of the present invention includes the following two steps.

a) a step of applying a solution containing a polyimide precursor to a support substrate, wherein the solution containing the polyimide precursor contains a polyimine obtained by reacting a tetracarboxylic acid component and a diamine component Precursors and solvents

b) a step of heating the polyimide film precursor film containing the coating film of the above solution containing the polyimide precursor at a temperature higher than the glass transition temperature of the transparent polyimide layer

The transparent polyimide laminate of the present invention can be produced, for example, in the form of a long transparent polyimide laminate 30 by the apparatus shown in FIG. The manufacturing apparatus shown in FIG. 1 includes a coating device 20 for a polyimide precursor, an endless belt 21, and a plurality of heating furnaces 10 arranged along the moving direction of the endless belt 21. On the support substrate 11 wound from the roll, the polyimide precursor is applied by the coating device 20 to form a coating film 1 of the polyimide precursor. Then, the coating film of the polyimide precursor is imidized by the heating furnace 10, and the transparent polyimide polyimide laminated body which laminated the support base material 11 and the transparent polyimine layer 1' is obtained. Thereafter, a long strip of transparent polyimide laminate was taken up to form a roll body 30.

1. About step a)

A solution containing a polyimide precursor is prepared, and the solution containing the polyimide precursor contains a polyimide precursor and a solvent obtained by reacting a tetracarboxylic acid component and a diamine component. The type of the polyimide precursor contained in the solution containing the polyimide precursor is not particularly limited, and from the viewpoint of improving the total light transmittance of the obtained transparent polyimide layer, it is preferably The polyimine precursor has an alicyclic group in its main chain. A solution containing a polybendimimine precursor containing such a polyimide precursor is described in detail below.

The prepared solution containing the polyimide precursor is applied to a support substrate. The support substrate is not particularly limited as long as it has solvent resistance and heat resistance. support The support substrate is preferably one having a good peelability from the transparent polyimide layer, and is preferably a flexible substrate containing a metal or a heat-resistant polymer film. Examples of the flexible substrate comprising a metal include: copper, aluminum, stainless steel, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zirconium, gold, cobalt, titanium, lanthanum, zinc, lead, tin, A metal foil of tantalum, niobium, indium or an alloy of these metals. A release agent may also be applied to the surface of the metal foil.

Further, examples of the flexible substrate including the heat resistant polymer film include a polyimine film, an aromatic polyamide film, a polyether ether ketone film, and a polyether ether oxime film. The flexible substrate including the heat resistant polymer film may further contain a release agent or an antistatic agent, and may be coated with a release agent or an antistatic agent on the surface. The support substrate is preferably a polyimide film in terms of good releasability with the obtained transparent polyimide layer and high heat resistance and solvent resistance.

The ten-point average roughness (Rz) of the surface of the support substrate is preferably less than 0.4 μm, more preferably 0.2 μm or less, and still more preferably 0.1 μm or less. When the ten-point average roughness of the surface of the support substrate is small, the haze value of the transparent polyimide layer formed on the support substrate tends to be small. The ten-point average roughness (Rz) of the surface of the support substrate is a value measured in the width direction of the support substrate in accordance with the value measured in accordance with JIS B-0601.

Further, it is preferable that the surface of the support substrate does not contain defects such as adhesion of foreign matter or streaky flaws. Even if the above-mentioned ten-point average roughness (Rz) is low, when the defects are present on the support substrate, the haze value of the obtained transparent polyimide layer is likely to become large. Defects on the surface of the support substrate can be evaluated by using "number of defects per unit area". Defects can be confirmed by visual observation. Support substrate per 210 The number of defects contained in the mm × 297 mm (A4 size) is preferably 10 or less, more preferably 5 or less, and still more preferably 1 or less.

The shape of the support substrate is appropriately selected depending on the shape of the transparent polyimide laminate to be produced, and may be a single sheet or an elongated strip. The thickness of the support substrate is preferably from 5 μm to 150 μm, more preferably from 10 μm to 70 μm. If the thickness of the support substrate is less than 5 μm, wrinkles may be generated in the support substrate during the application of the solution containing the polyimide precursor, or the support substrate may be broken.

The application of the solution containing the polyimide precursor to the support substrate is not particularly limited as long as it is a solution capable of coating a solution containing a polyimide precursor with a certain film thickness. Examples of the coating device include a die coater, a comma coater, a roll coater, a gravure coater, a curtain coater, a spray coater, and a lip coater ( Lip coater) and so on.

The thickness (coating film thickness) of the coating film of the solution containing the polyimide precursor is based on the thickness of the desired transparent polyimide layer or the polyimine in the solution containing the polyimide precursor The concentration of the precursor is appropriately selected.

2. About step b)

In the step b), the coating film of the solution containing the polyamidiamine precursor formed on the support substrate in the above step a), that is, the polyimide precursor film is heated. Specifically, it is preferably a step of: i) heating the surface of the polyimide precursor film from a temperature of 150 ° C or lower to a temperature exceeding 200 ° C; and further ii) obtaining the transparent poly The temperature of the bismuth imide layer above the glass transition temperature (certain temperature) is heated for a certain period of time.

i) The temperature at which the usual polyimine precursor is subjected to hydrazine imidation is from 150 ° C to 200 ° C. Therefore, if the temperature of the polyimide precursor film is rapidly increased to 200 ° C or higher, the polyimide film precursor on the surface of the coating film is subjected to volatilization before the solvent is volatilized from the polyimide film. Amination. Further, the solvent in the coating film is foamed, or irregularities are generated on the surface of the coating film when the solvent is released to the outside. Therefore, it is preferred to gradually increase the temperature of the polyimide precursor film in a temperature range of from 150 ° C to 200 ° C. Specifically, it is preferable to set the temperature increase rate in the temperature range of 150 ° C to 200 ° C to 0.25 ° C / min to 50 ° C / min, more preferably 1 ° C / min to 40 ° C / min, and further preferably 2 ° C /min~30°C/min.

The temperature rise may be a continuous temperature increase or a stepwise (sequential) temperature increase, and it is preferable to set the continuous temperature increase in terms of suppressing the appearance defect of the obtained transparent polyimide layer. Further, the temperature increase rate may be constant over the entire temperature range as described above, or may be changed midway.

In an example of a method of heating a monolithic polyimide precursor film while heating, there is a method of increasing the temperature in the oven for heating the polyimide precursor film. In this case, the rate of temperature increase is adjusted by the setting of the oven. Further, when the temperature is raised to face the elongated polyimide precursor film, for example, as shown in FIG. 1, a plurality of pairs are arranged in the transport (moving) direction of the support substrate 11. The heating furnace 10 in which the yttrium imine precursor film 1 is heated; the temperature of the heating furnace 10 is changed in accordance with each heating furnace 10. For example, the temperature of each heating furnace 10 may be increased along the moving direction of the support substrate 11. In this case, the temperature increase rate is adjusted by the conveyance speed of the support base material 11.

Ii) Heating the polyimide precursor film while heating the temperature, and then heating at a temperature (certain temperature) above the glass transition temperature of the obtained transparent polyimide layer for a certain period of time. The temperature at this time is not particularly limited as long as it is at least the glass transition temperature of the obtained transparent polyimide layer, and is more preferably a temperature higher than the glass transition temperature of the obtained transparent polyimide layer by 5 to 30 ° C. Further, it is preferred that the glass transition temperature of the obtained transparent polyimide layer is higher by 5 ° C to 20 ° C. The polyimine precursor can be sufficiently imidized by heating at a temperature above the glass transition temperature of the resulting transparent polyimide layer for a certain period of time. Further, since the glass is heated at a temperature higher than the glass transition temperature of the obtained transparent polyimide layer for a certain period of time, the transparent polyimide layer is softened, and the solvent inside the transparent polyimide layer is sufficiently volatilized. The heating time at a temperature higher than the glass transition temperature is appropriately selected depending on the heating temperature, the thickness of the polyimide precursor film, the amount of the solvent contained in the solution containing the polyimide precursor, and the like. It is usually about 0.5 hours to 2 hours.

The heating method for heating the polyimide precursor film at a certain temperature is not particularly limited, and for example, heating is performed using an oven or the like which has been adjusted to a constant temperature. Further, the long polyimine precursor film is heated by a heating furnace or the like held at a constant temperature.

Polyimine is easily oxidized if it is heated at a temperature exceeding 200 °C. If the polyimine is oxidized, the resulting transparent polyimide layer undergoes yellowing, and the total light transmittance of the transparent polyimide layer decreases. Therefore, in the temperature range exceeding 200 ° C, it is preferred to (i) set the oxygen concentration of the heating atmosphere to 5 vol% or less, or (ii) decompress the heating atmosphere.

(i) When the oxygen concentration in the heating atmosphere is set to 5 vol% or less, the oxidation reaction of the polyimine is suppressed. The oxygen concentration in the temperature range of more than 200 ° C is more preferably 3% by volume or less, and still more preferably 1% by volume or less. The method for lowering the oxygen concentration is not particularly limited, and may be a method of introducing an inert gas into a heating atmosphere. The oxygen concentration in the atmosphere is measured using a commercially available oxygen concentration meter (for example, a zirconia oxygen concentration meter).

(ii) Further, by decompressing the heated atmosphere, the oxidation reaction of the polyimine is also suppressed. When the heating atmosphere is depressurized, the pressure in the atmosphere is preferably set to 5 kPa or less, more preferably 1 kPa or less. When the heated atmosphere is depressurized, the polyimine precursor film is heated by a vacuum oven or the like.

The b-9 imidization ratio of the transparent polyimide layer at the end of the heating step is preferably 90% or more, more preferably 93% or more, and still more preferably 95% or more. If the imidization ratio is less than 90%, it is possible to carry out oxime imidization when a transparent polyimide layer is used, and release water from the transparent polyimide layer. The ruthenium amination ratio can be calculated from the measured value of the infrared ray (IR) absorption spectrum of the transparent polyimide layer. Specifically, it is calculated by the following method.

The transparent polyimide layer was peeled off from the support substrate, and its IR absorption spectrum was measured. Then, the ratio of the absorption peak height of 1370 cm ^-1 (the CN stretching vibration of the quinone ring) to the absorption peak height of 1500 cm ^-1 (the peak (base) obtained by the C=C stretching vibration of the benzene ring) was calculated. A. On the other hand, a polyimine precursor film containing a solution of the polyimide-containing precursor having the same composition was produced, and it was heated at 270 ° C for 2 hours or more to be completely imidized. The IR absorption spectrum of the film was also measured, and the absorption peak height of 1370 cm ^-1 (CN stretching vibration of the quinone ring) was calculated in the same manner as the absorption peak height of 1500 cm ^-1 (C=C stretching vibration of the benzene ring) The ratio B of the obtained peak (reference). Then, the value of the ratio A with respect to the ratio B (ratio A/ratio B) × 100 (%) was determined, and this was taken as the ruthenium iodization ratio.

On the other hand, at the end of the step b), the amount of the solvent remaining in the transparent polyimine layer (the mass of the remaining solvent × 100 / the mass of the transparent polyimide layer) is preferably 1.0% by mass or less. It is more preferably 0.8% by mass or less, and still more preferably 0.5% by mass or less. If the residual amount of the solvent exceeds 1.0% by mass, it is possible to release the solvent from the transparent polyimide layer when the transparent polyimide layer is used. The residual amount of the solvent is determined by peeling off the transparent polyimide layer on the self-supporting substrate, thermally decomposing the transparent polyimide layer by an electric furnace type thermal decomposition furnace, or the like by gas chromatography mass spectrometry. The components obtained by thermal decomposition were analyzed.

After the completion of the above heating, when the obtained transparent polyimide polyimide laminate is in the form of a strip, the transparent polyimide polyimide laminate may be wound up as described above to form a roll.

3. About the solution containing the polyimide precursor

The solution containing the polyimine precursor coated in the step a) contains a polyimide precursor and a solvent, and if necessary, a release agent. When the release agent is contained in the solution containing the polyimide precursor, the peeling property of the transparent polyimide layer in the transparent polyimide laminate and the support substrate is improved. Further, the solution containing the polyimide precursor may contain various additives as needed.

3-1. Polyimine precursor

The polyimine precursor is obtained by reacting a tetracarboxylic acid component (A) with a diamine component (B). The concentration of the polyimine precursor contained in the solution containing the polyimide precursor is preferably from 5% by mass to 50% by mass, more preferably from 10% by mass to 40% by mass. When the concentration of the polyimide precursor is more than 50% by mass, the viscosity of the solution containing the polyimide precursor may become too high, and application to the support substrate may become difficult. On the other hand, when the concentration of the polyimide precursor is less than 5% by mass, the viscosity of the solution containing the polyimide precursor may be too low, and the polyimide film may not be coated. The thickness required. Further, drying of the solvent takes time, and the production efficiency of the polyimide film is deteriorated.

3-1-1. Tetracarboxylic acid component (A)

The tetracarboxylic acid component (A) constituting the polyimide precursor has a tetracarboxylic dianhydride represented by the following formula (a). The tetracarboxylic acid component (A) may contain only one tetracarboxylic dianhydride represented by the formula (a), or may contain two or more kinds.

In the formula (a), R ¹ represents a tetravalent organic group having 4 to 27 carbon atoms. R ¹ may be an aliphatic group; a monocyclic aliphatic group; a condensed polycyclic aliphatic group; a monocyclic aromatic group; a condensed polycyclic aromatic group; a cyclic aliphatic group directly or by a crosslinker A non-condensed polycyclic aliphatic group which is bonded to each other; a non-condensed polycyclic aromatic group in which an aromatic group is directly or by a crosslinker.

The tetracarboxylic dianhydride represented by the formula (a) is particularly preferably an aromatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride.

Examples of the aromatic tetracarboxylic dianhydride represented by the formula (a) include: pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)thioether dianhydride, double (3, 4-Dicarboxyphenyl)ruthenic anhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-double (3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1 , 4-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 4,4'-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3, 4-Dicarboxyphenoxy)phenyl]propane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane II Anhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride , bis(2,3-dicarboxyphenyl) sulfide dianhydride, bis(2,3-dicarboxyphenyl)ruthenic anhydride, 1,3-bis(2,3-dicarboxyphenoxy)benzene Anhydride, 1,4 -bis(2,3-dicarboxyphenoxy)phthalic anhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxybenzylidene)benzene Dihydride, 1,4-bis(3,4-dicarboxybenzylidene)phthalic anhydride, 1,3-bis(2,3-dicarboxybenzylidene)phthalic anhydride, 1,4-double (2,3-dicarboxybenzimidyl)phthalic anhydride, 4,4'-m-xylylenediamine phthalic anhydride diazodiphenylmethane-3,3',4,4'-tetracarboxylic acid Diacetate, diazodiphenylmethane-2,2',3,3'-tetracarboxylic acid Dianhydride, 2,3,6,7-thioxanthone tetracarboxylic dianhydride, 2,3,6,7-nonanetetracarboxylic dianhydride, 2,3,6,7-oxaxanthene Xanthone tetracarboxylic dianhydride and the like.

Examples of the alicyclic tetracarboxylic dianhydride represented by the formula (a) include: cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2 , 4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2 , 3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride Bicyclo[2.2.1]heptane-2,3,5-tricarboxylic acid-6-acetic acid dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3-(1,2), 5,6-tetracarboxylic dianhydride, decahydro-1,4,5,8-dimethylnaphthalene-2,3,6,7-tetracarboxylic dianhydride, 4-(2,5-dioxo Tetrahydrofuran-3-yl)-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, and the like.

When the tetracarboxylic dianhydride represented by the formula (a) contains an aromatic ring such as a benzene ring, a part or all of the hydrogen atom in the aromatic ring may be a fluorine group, a methyl group, a methoxy group or a trifluoromethyl group. Substituted with a trifluoromethoxy group or the like. In the case where the tetracarboxylic dianhydride represented by the formula (a) contains an aromatic ring such as a benzene ring, the structure of the tetracarboxylic acid may be selected from the group consisting of an ethynyl group and a benzocyclobutene. a group which becomes a crosslinking point in -4'- group, vinyl group, allyl group, cyano group, isocyanate group, nitrilo, and isopropenyl group. In particular, in the tetracarboxylic dianhydride represented by the general formula (a), a vinyl group, a vinylidene group, an exoacetylene group or the like is a crosslinking point insofar as the moldability is not impaired. The group is grouped into the backbone of the backbone.

In addition to the tetracarboxylic dianhydride represented by the above formula (a), the tetracarboxylic acid component (A) may contain a hexacarboxylic acid trianhydride or an octacarboxylic acid tetrahydride. When these acid anhydrides are contained, a branched chain is introduced into the obtained polyimine. These acid anhydrides can only It contains one kind, and it can also contain two or more types.

3-1-2. Diamine component (B)

The diamine component (B) constituting the polyimide precursor is a diamine represented by the following formula (b-1) to formula (b-3). The diamine component (B) may contain only one type of diamine represented by the following formula (b-1) to formula (b-3), or may contain two or more types. Further, the diamine component (B) may contain a diamine (b-4) other than the diamine represented by the formula (b-1) to the formula (b-3).

Among the cyclohexane skeletons of cyclohexanediamine represented by the formula (b-1), there are the following two geometric isomers (cis/trans). The trans form is represented by the following formula (Z-1), and the cis form is represented by the following formula (Z-2).

The cis/trans group of the cyclohexane skeleton in the formula (Z-1) is preferably from 50/50 to 0/100, more preferably from 30/70 to 0/100. If the proportion of the trans is higher, the molecular weight of the polyimide precursor is generally increased. Therefore, the strength of the film is easily improved.

The cis/trans ratio of the cyclohexane-derived unit contained in the polyimide precursor is determined by nuclear magnetic resonance spectroscopy.

The position of the aminomethyl group of the norbornanediamine represented by the formula (b-2) is not particularly limited. For example, the norbornanediamine represented by the formula (b-2) may further contain a structural isomer having a different position of the aminomethyl group or an optical isomer containing the S body or the R body. These isomers can also be included in any ratio.

In the 1,4-bismethylenecyclohexane skeleton (X) of 1,4-bis(aminomethyl)cyclohexane represented by the formula (b-3), there are two geometric isomers ( Cis-type/trans-body). The trans form is represented by the following formula (X1), and the cis form is represented by the following formula (X2).

The cis/trans ratio of the unit derived from 1,4-bis(aminomethyl)cyclohexane is preferably from 40/60 to 0/100, more preferably from 20/80 to 0/100. The glass transition temperature of the polyimine containing the diamine represented by the formula (b-3) in the constituent component is controlled by the above cis/trans ratio, and if the ratio of the trans form (X1) is increased, Then, the glass transition temperature of the polyimide is increased.

The cis/trans ratio of the unit derived from 1,4-bis(aminomethyl)cyclohexane contained in the polyimide precursor is determined by nuclear magnetic resonance spectroscopy.

The diamine component (B) may contain a diamine (b-4) represented by the following formula other than the diamine represented by the above formula (b-1) to formula (b-3).

In the formula (b-4), R' is a divalent group having 4 to 51 carbon atoms. R' may be an aliphatic group; a monocyclic aliphatic group (wherein a 1,4-cyclohexylene group, a group represented by the following formula (X), and a group represented by the following formula (Y)) Except for the group); condensation polycyclic An aliphatic group; a monocyclic aromatic group; a condensed polycyclic aromatic group; a non-condensed polycyclic aliphatic group in which a cyclic aliphatic group is bonded directly or by a crosslinker; an aromatic group directly or A non-condensed polycyclic aromatic group formed by linking crosslinkers.

Examples of the diamine represented by the above formula (b-4) include a diamine having a benzene ring, a diamine having an aromatic substituent, a diamine having a spirobiindan ring, and a decane. Diamines, ethylene glycol diamines, alkylenediamines, alicyclic diamines, and the like.

Examples of the diamine having a benzene ring include: <1> a diamine having one benzene ring such as p-phenylenediamine, m-phenylenediamine, p-xylenediamine or m-xylenediamine; <2>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'-diaminodiphenylanthracene, 3,4'-diamino Diphenylanthracene, 4,4'-diaminodiphenylanthracene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-di Aminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodi Phenylmethane, 3,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2-( 3-aminophenyl)-2-(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl)-2-(4-aminophenyl) )-1,1,1,3,3,3-hexafluoropropane, 1,1-bis(3-aminophenyl)-1-phenylethane, 1,1-di(4-aminobenzene) a diamine having two benzene rings, such as 1-phenylethane or 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane; <3 >1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1 , 4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzimidyl)benzene, 1,3-bis(4-aminobenzylidene)benzene, 1 , 4-bis(3-aminobenzimidyl)benzene, 1,4-bis(4-aminobenzimidyl)benzene, 1,3-bis(3-amino-α,α-dimethyl Benzyl)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-di-trifluoromethylbenzyl)benzene 1,3-double 4-amino-α,α-di-trifluoromethylbenzyl)benzene, 1,4-bis(3-amino-α,α-di-trifluoromethylbenzyl)benzene, 1,4- Bis(4-amino-α,α-di-trifluoromethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzonitrile, 2,6-bis(3-aminobenzene a diamine having three benzene rings such as oxy)pyridine; <4>4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy) Biphenyl, bis[4-(3-aminophenoxy)phenyl]one, bis[4-(4-aminophenoxy)phenyl]one, bis[4-(3-aminophenoxy) Phenyl] thioether, bis[4-(4-aminophenoxy)phenyl] sulfide, bis[4-(3-aminophenoxy)phenyl]indole, bis[4-( 4-aminophenoxy)phenyl]indole, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2 , 2-double [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 a diamine having 4 benzene rings such as 1,3,3,3-hexafluoropropane; <5>1,3-bis[4-(3-aminophenoxy)benzylidene]benzene, 1 , 3-bis[4-(4-aminophenoxy)benzylidene]benzene, 1,4-bis[4-(3-aminophenoxy)benzylidene]benzene, 1,4 - bis[4-(4-aminophenoxy)benzylidene]benzene, 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene , 1,3-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α a diamine having 5 benzene rings, such as α-dimethylbenzyl]benzene, 1,4-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene; <6>4,4'-bis[4-(4-aminophenoxy)benzylidene]diphenyl ether, 4,4'-bis[4-(4-amino-α,α- Dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenylphosphonium, 4 a diamine having 6 benzene rings such as 4'-bis[4-(4-aminophenoxy)phenoxy]diphenylphosphonium.

Examples of the diamine having an aromatic substituent include: 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'- Diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, and the like.

Examples of the diamine having a spirobifluorene ring include: 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spiro Indole, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobifluorene, and the like.

Examples of the oxane diamines include: 1,3-bis(3-aminopropyl)tetramethyl Dioxane, 1,3-bis(4-aminobutyl)tetramethyldioxane, α,ω-bis(3-aminopropyl)polydimethyloxane, α,ω - bis(3-aminobutyl)polydimethyloxane or the like.

Examples of ethylene glycol diamines include: bis(aminomethyl)ether, bis(2-aminoethyl)ether, bis(3-aminopropyl)ether, bis[(2-aminocarbyl) Oxy)ethyl]ether, bis[2-(2-aminoethoxy)ethyl]ether, bis[2-(3-aminopropoxy)ethyl]ether, 1,2-double ( Aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane, 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1, 2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl)ether, diethylene glycol bis(3-aminopropyl)ether , triethylene glycol bis(3-aminopropyl)ether, and the like.

Examples of alkylenediamines include: ethyl diamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-di Aminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminodecane, 1,10-diaminodecane, 1,11-di Aminoundecane, 1,12-diaminododecane, and the like.

Examples of the alicyclic diamines include: cyclobutanediamine, cyclohexanediamine, bis(aminomethyl)cyclohexane [except 1,4-bis(aminomethyl)cyclohexane Bis(aminomethyl)cyclohexane], diaminobicycloheptane, diaminomethylbicycloheptane (including norbornane diamines such as norbornanediamine), diaminooxybicyclo Heptane, diaminomethyloxybicycloheptane (containing oxabornane diamine), isophorone diamine, diaminotricyclodecane, diaminomethyltricyclodecane, double (Aminocyclohexyl)methane [or methylene bis(cyclohexylamine)], bis(aminocyclohexyl)isopropylidene, and the like.

3-1-3. Preferred Polyimine Precursor

The polyimine precursor contained in the solution containing the polyimide precursor is only the above The tetracarboxylic acid component (A) is not particularly limited as long as it reacts with the above diamine component (B), and the polyamidene precursor is preferably a block polyamidimide, and the block is polycondensed. The bismuth imidate is a polyamic acid block of a tetracarboxylic dianhydride represented by the above formula (a) and a diamine represented by the formula (b-1) (by the following formula (G) And the dicarboxylic acid dianhydride represented by the formula (a) and the diamine represented by any one of the formula (b-2), the formula (b-3) or the formula (b-4) The polyimine block (indicated by the following general formula (H)) is bonded.

In the general formula (G) and the general formula (H), R ⁶ and R ⁸ each independently represent a tetravalent group having 4 to 27 carbon atoms. R ⁶ and R ⁸ may be independently aliphatic; monocyclic aliphatic; condensed polycyclic aliphatic; monocyclic aromatic; or condensed polycyclic aromatic; cycloaliphatic directly Or a non-condensed polycyclic aliphatic group which is linked to each other by a crosslinker; a non-condensed polycyclic aromatic group in which an aromatic group is directly or by a crosslinker. Specifically, it is the same as R ¹ in the tetracarboxylic dianhydride represented by the above formula (a).

Further, in the formula (H), R ⁷ represents a divalent group having 4 to 51 carbon atoms. R ⁷ may be an aliphatic group; a monocyclic aliphatic group (excluding 1,4-cyclohexylene); a condensed polycyclic aliphatic group; a monocyclic aromatic group or a condensed polycyclic aromatic group; A non-condensed polycyclic aliphatic group in which a cyclic aliphatic group is directly or by a cross-linking member; a non-condensed polycyclic aromatic group in which an aromatic group is bonded to each other directly or by a cross-linking member. Specifically, it may be the same as R' of the diamine represented by the above formula (b-4) or a group represented by the following formula (X) or formula (Y).

R ⁷ in the formula (H) is particularly preferably a norbornane (group represented by the above formula (Y)). In other words, the polyimine block represented by the formula (H) is preferably a block of a polyimine containing the diamine represented by the above formula (b-2).

m and n in the formula (G) and the formula (H) represent the number of repetitions of the repeating structural unit of each block. The average value of m and the average value of n are each independently preferably from 2 to 1,000, and more preferably from 5 to 500.

The ratio of m to n is preferably the average value of m: the average value of n = 9:1 to 1:9, more preferably the average value of m: the average value of n = 8:2 to 2:8. When the ratio of the number of repetitions m of the repeating structural unit represented by the formula (G) is at least a certain value, the thermal expansion coefficient of the obtained polyimide film becomes small. In addition, if the ratio of the number of repetitions m is constant or more, The visible light transmittance of the obtained polyimide film is improved. On the other hand, since cyclohexanediamine is usually expensive, if the ratio of the number of repetitions of the repeating structural unit represented by the formula (G) is reduced, the cost can be reduced.

The total number of repeating structural units represented by the formula (G) contained in the block polyphosphonium imide of the polyimine precursor may be better than the total number of repeating structural units represented by the formula (H). (G): (H) = 9:1 to 1:9, more preferably (G): (H) = 8:2 to 2:8.

3-2. Solvent

The solvent contained in the solution containing the polyimide precursor is not particularly limited as long as it can dissolve the tetracarboxylic acid component (A) and the diamine component (B). For example, it may be an aprotic polar solvent or a water-soluble alcohol solvent.

Examples of the aprotic polar solvent include: N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl azine, six Methylphosphoniumamine, 1,3-dimethyl-2-imidazolidinone, etc.; 2-methoxyethanol, 2-ethoxyethanol, 2-(methoxymethoxy) as an ether compound Ethoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl Ether, triethylene glycol, triethylene glycol monoethyl ether, tetraethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, Dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, polypropylene glycol, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether Wait.

Examples of the water-soluble alcohol-based solvent include methanol, ethanol, and 1-propanol. 2-propanol, tert-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 1,2,6-hexanetriol, diacetone alcohol, and the like.

The solution containing the polyimide precursor may contain only one of the solvents, or may contain two or more kinds. The solvent preferably contains N,N-dimethylacetamide, N-methyl-2-pyrrolidone or a mixture of the solvents.

3-3. Release agent

The solution containing the polyimide precursor may also contain a release agent. The release agent contained in the solution containing the polyimide precursor is not particularly limited as long as it can improve the release property of the support substrate and the transparent polyimide layer, and may be a known internal mold release agent. Examples of the internal mold release agent include aliphatic alcohols, fatty acid esters, triglycerides, fluorine-based surfactants, higher fatty acid metal salts, and phosphate-based release agents. From the viewpoint of not impairing the transparency of the obtained transparent polyimide layer, a phosphate-based release agent is preferred. Examples of the phosphate ester-based release agent include the compounds described in JP-A-2000-256377.

The amount of the releasing agent contained in the solution containing the polyimide precursor is preferably 0.01 parts by mass relative to 100 parts by mass of the polyimine precursor contained in the solution containing the polyimide precursor. 0.38 parts by mass, more preferably 0.02 parts by mass to 0.30 parts by mass, further preferably 0.04 parts by mass to 0.20 parts by mass. When the amount of the releasing agent is less than 0.01 parts by mass, the peeling strength when the transparent polyimide layer is peeled off from the supporting substrate is increased. On the other hand, when the amount of the releasing agent exceeds 0.38 parts by mass, it is difficult to apply the solution containing the polyimide precursor to the supporting substrate.

3-4. Other additives

As described above, in the solution containing the polyimide precursor, various additives may be contained in a range that does not impair the transparency and heat resistance of the obtained transparent polyimide layer. Examples of various additives include: an antioxidant, a heat stabilizer, an antistatic agent, a flame retardant, and an ultraviolet absorber.

3-5. Method for preparing solution containing polyimine precursor

The solution containing the polyimine precursor is obtained by reacting the above tetracarboxylic acid component (A) with the above diamine component (B) in the above solvent. When the number of moles of the diamine component (B) in the solvent is set to x and the number of moles of the tetracarboxylic acid component (A) is set to y, y/x is preferably 0.9 to 1.1, more preferably 0.95. 1.05, and then preferably 0.97~1.03, especially preferably 0.99~1.01. By polymerizing the tetracarboxylic acid component (A) and the diamine component (B) in such a ratio, the molecular weight (degree of polymerization) of the polyimide precursor can be appropriately adjusted.

The order of the polymerization reaction is not particularly limited. For example, first, a container equipped with a stirrer and a nitrogen gas introduction pipe is prepared. The solvent to be described later is placed in a nitrogen-substituted container, and the diamine is added so that the solid content concentration of the obtained polyamidene precursor is 50% by mass or less, and the temperature is adjusted, stirred, and dissolved. In this solution, the tetracarboxylic acid component (A) is added so that the molar ratio becomes 1 with respect to the diamine component (B), and the temperature is adjusted and stirred for about 1 to 50 hours, whereby the polyazide can be obtained. A solution of a polyamide precursor containing a polyimide precursor.

In the case where the polyimine precursor is set to the block polyamidimide, for example, a polyimine solution having an acid anhydride at the end is added to the polyamine acid solution having an amine at the end, and stirring is performed. In order to produce polyphosphonium imide. The diamine unit of polyproline is preferably a cyclohexane-containing diamine (diamine represented by the above formula (b-1) or (b-3)); polyimine The diamine unit is preferably a diamine (diamine represented by the above formula (b-2) or (b-4)) other than the cyclohexane-containing diamine. The reason for this is that polycycloimine containing cyclohexane in the structure (diamine represented by (b-1) or (b-3)) may be difficult to dissolve in a solvent. Polylysine is produced by the above method. Further, the release agent is appropriately added as needed.

4. About the transparent polyimide layer

The transparent polyimide layer in the transparent polyimide laminate obtained by the above method has a total light transmittance of 80% or more, more preferably 83% or more, still more preferably 85% or more. When the total light transmittance is 80% or more, the transparent polyimide layer can be applied to applications requiring transparency. The total light transmittance of the transparent polyimide layer is adjusted by the type of polyimine, the oxygen concentration or pressure of the atmosphere in the above step b), and the like. In particular, by reducing the oxygen concentration of the atmosphere in the temperature range of more than 200 ° C in step b) or lowering the pressure of the atmosphere, the oxidation of the polyimine is suppressed, and the total light transmittance of the transparent polyimide layer is improved. The total light transmittance is a peeling of the transparent polyimide layer on the self-supporting substrate, and the transparent polyimide layer is measured in accordance with JIS-K7105 and using the light source D65.

Further, the in-plane phase difference of the transparent polyimide layer in the transparent polyimide layer laminate is 10 nm or less, preferably 5 nm or less, and more preferably 3 nm or less. When the in-plane phase difference of the transparent polyimide layer is 10 nm or less, the transparent polyimide layer can be applied to a panel substrate or the like of a flexible display device. If the above steps b) After the end of the hydrazine imidization, or the solvent is volatilized, the in-plane phase difference is likely to become large. Therefore, in order to reduce the in-plane retardation, it is preferred to sufficiently increase the ruthenium imidization ratio at the end of the above step b), and to sufficiently reduce the amount of residual solvent at the end of the step b). The in-plane phase difference is a value measured by a photoelastic constant measuring device at 25 ° C with light having a wavelength of 550 nm. Specifically, the transparent polyimide layer is peeled off from the support substrate, and the refractive index of the transparent polyimide layer is measured by a photoelastic constant measuring device, and the direction in which the refractive index is maximized is set to the X axis, and the X The direction in which the axis is perpendicular is set to the Y axis. Then, when the refractive index in the X-axis direction is set to nx, the refractive index in the Y-axis direction is set to ny, and the thickness of the transparent polyimide layer is set to d, the value represented by (nx-ny) × d is taken as In-plane phase difference.

The glass transition temperature (Tg) of the transparent polyimide layer in the transparent polyimide laminate is 260 ° C or higher, preferably 270 ° C or higher, and more preferably 300 ° C or higher. When the glass transition temperature of the transparent polyimide layer is 260 ° C or higher, the transparent polyimide layer can also be applied to applications requiring high heat resistance. For example, the temperature at which the electronic component is usually formed is 250 ° C, and the transparent polyimide layer obtained in the present invention can also be applied to a panel substrate or the like of an apparatus including such an electronic component. The glass transition temperature of the transparent polyimide layer is adjusted, for example, by the equivalent of the quinone imine group contained in the polyimide, the structure of the diamine component constituting the polyimide, or the structure of the tetracarboxylic dianhydride component. . The above glass transition temperature was measured using a Thermomechanical Analyzer (TMA).

The transparent polyimide layer in the transparent polyimide laminate has a haze value of 5% or less, preferably 3% or less, and further preferably 1% or less. If the transparent polyimide layer When the haze value is 5% or less, the transparent polyimide layer can be applied to various optical films. The haze value of the transparent polyimide layer is adjusted by the heating conditions of the solution containing the polyimide precursor, the crystallinity of the polyimide, the surface roughness of the support substrate, and the like.

Further, the absolute value of the b value expressed by the L*a*b color system of the transparent polyimide layer in the transparent polyimide composition is preferably 5 or less, preferably 3 or less. On the other hand, the b value is preferably a positive value (0 or more). The L*a*b color system is based on JIS Z 8729. If the b value is positive, it means that the transparent polyimide layer has a yellow color, and if the b value is a negative value, it means that the transparent polyimide layer has a blue color. Moreover, most of the usual polyimide membranes have a large b value and are yellow or brownish brown. On the other hand, the transparent polyimine layer in the transparent polyimine laminate of the present invention has an absolute value of b value of 5 or less and less coloration. Therefore, the polyimide layer can also be applied to substrates or the like of various displays.

The thickness of the transparent polyimide layer in the transparent polyimide laminate is not particularly limited, and is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm. The transparent polyimide layer having such a thickness can be used as a substrate for various flexible elements and the like.

Here, the present invention also provides a polyimide film having a glass transition temperature of 260 ° C or higher, a total light transmittance of 80% or more, a haze value of 5% or less, and b in an L*a*b color system. The absolute value of the value is 5 or less, and the in-plane phase difference is 10 nm or less. The polyimine film preferably contains a transparent polyimide layer obtained by the above-described method for producing a transparent polyimide laminate. Further, the physical properties of the polyimide film are preferably in the same range as the above polyimine layer.

B. Use of transparent polyimide polyimide laminates

The transparent polyimide film obtained by peeling the transparent polyimide layer of the above transparent polyimide layer laminate from the support substrate can be applied to a substrate or an optical film of various flexible elements. Further, the transparent polyimide film is particularly suitable for a substrate of a flexible display because it has a high total light transmittance and a very small in-plane phase difference. Examples of the flexible display include a touch panel, a liquid crystal display, an organic EL display, and the like.

The touch panel is generally a panel body including (i) a transparent substrate having a transparent electrode (detection electrode layer), (ii) an adhesive layer, and (iii) a transparent substrate having a transparent electrode (drive electrode layer). The transparent polyimide film can be applied to any one of a transparent substrate on the side of the detection electrode layer and a transparent substrate on the side of the drive electrode layer.

Further, the liquid crystal cell of the liquid crystal display device is generally provided with a laminated structure in which (i) a first transparent plate, (ii) a liquid crystal material sandwiched by a transparent electrode, and (iii) a second transparent plate are sequentially laminated. Panel body. The transparent polyimide film can be applied to any of the first transparent plate and the second transparent plate. Further, the above transparent polyimide film can also be applied to a substrate for a color filter in a liquid crystal display device.

The organic EL panel is usually a panel in which a transparent substrate, an anode transparent electrode layer, an organic EL layer, a cathode reflective electrode layer, and a counter substrate are sequentially laminated. The transparent polyimide film can be applied to any of the transparent substrate and the counter substrate.

The transparent polyimide layer (transparent polyimide film) of the above transparent polyimide laminate can be easily peeled off from the support substrate. Therefore, when the flexible display is obtained, the transparent polyimide layer can be peeled off and the component is formed on the transparent polyimide layer. The transparent polyimide layer can be peeled off from the support substrate after the component is formed on the transparent polyimide layer.

When the transparent polyimide layer is peeled off from the support substrate, foreign matter may be adsorbed on the transparent polyimide layer by peeling electrification or damage to the element. Therefore, it is preferred to carry out measures for preventing charging of the transparent polyimide polyimide laminate. Specifically, it is preferred to (a) add an antistatic agent to the solution containing the polyimide precursor; (b) apply an antistatic agent to the support substrate; (c) precursor containing the polyimine A static eliminating member (for example, a static eliminating bar, a wire removing wire, an ion blowing type static eliminating device, etc.) is provided in the coating device of the solution of the solution or the peeling device of the transparent polyimide layer. These countermeasures may be used alone or in combination.

The method of forming an element on a transparent polyimide layer includes the following three methods. Further, in any of the methods, the method of forming the element is not particularly limited, and may be a known method.

(i) the first method

As shown in the schematic cross-sectional view of Fig. 2, the first method is a method in which a transparent polyimide film (transparent polyimide layer) is peeled off from the support substrate 11 of the transparent polyimide laminate 12 (Fig. 2 (a)), the element 13 is formed on the transparent polyimide film 1' (Fig. 2 (b)). In the first method, the peeled transparent polyimide film 1' may be bonded to another substrate (not shown), and then the element 13 may be formed on the transparent polyimide film 1'.

(ii) the second method

As shown in the schematic cross-sectional view of Fig. 3, the second method is the following method: After the element 13 is formed on the transparent polyimide layer 1' of the substrate 11 (Fig. 3(a)), the transparent polyimide film (transparent polyimide layer) is peeled off from the support substrate 11. ((b) of Fig. 3), a transparent polyimide film 1' in which the element 13 is formed is obtained ((c) of Fig. 3). In the second method, the stress applied to the transparent polyimide layer 1' when the element 13 is formed is easily absorbed by the support substrate 11. Therefore, the transparent polyimide layer 1' is less likely to be broken or broken when the element 13 is formed.

(iii) the third method

As shown in the schematic cross-sectional view of Fig. 4, the third method is a method in which the support substrate 11 side of the transparent polyimide laminate 12 is bonded to another substrate 14 (Fig. 4 (a)). Various elements 13 are formed on the transparent polyimide layer 1' (Fig. 4(b)), and a transparent polyimide film (transparent polyimide layer) 1' is peeled off from the support substrate 11 (Fig. 4 ( c)), a polyimide film 1' in which the element 13 is formed is obtained ((d) of Fig. 4). In the third method, since the other substrate 14 is bonded to the transparent polyimide laminate 12, the transparent polyimide laminate 12 is not bent when the element 13 is produced. Therefore, the element 13 can be formed on the transparent polyimide layer 1' by various methods. Further, in the third method, the stress applied to the transparent polyimide layer 1' when the element 13 is formed is also easily absorbed by the support substrate 11. Therefore, the transparent polyimide layer 1' is less likely to be broken or broken when the element 13 is formed.

The other substrate 14 to be bonded to the transparent polyimide laminate 12 is not particularly limited as long as it has a rigid substrate, and may be a glass substrate, a metal substrate, a ceramic substrate, a resin substrate or the like. The bonding method of the support substrate 11 of the transparent polyimide laminate 12 and the other substrate 14 is not particularly limited, and for example, an adhesive may be used. The method of bonding, etc.

5. Other

The method for producing the above polyimine laminate can also be applied to a method for producing a resin laminate having a support substrate and various resin layers. Specifically, it can be set as a method of producing a resin laminate including the steps of: (a) applying a varnish containing various resins to a support substrate; and (b) heat-hardening the coating film of the varnish. A step of. According to the method for producing a resin laminate, a resin film which can be easily peeled off from the support substrate can be obtained. Examples of the various resins include a polyimine resin (polyimine precursor) other than the above, an aromatic polyamide resin, a polyether ether ketone resin, and a polyether oxime resin.

Example

Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the invention is not limited by the embodiments. In the examples and comparative examples, the peeling strength, the ruthenium iodide ratio, the residual amount of the solvent, the glass transition temperature, the total light transmittance, the haze value, and the b value in the L*a*b color system were measured by the following methods. , in-plane phase difference and ten point average roughness of the supporting substrate.

1) Peel strength

The transparent polyimide laminate produced in the examples and the comparative examples was cut into a length of 50 mm and a width of 3.5 mm. The transparent polyimide polyimide laminate was measured for peel strength in accordance with the method specified in JIS C-6471. Specifically, the short side end of the transparent polyimide laminate was gripped and peeled off from the support substrate under the conditions of a peeling angle of 90° and a peeling speed of 50 mm/min, and the stress at the time of peeling was measured. The stress is made by Shimadzu Corporation The tensile tester EZ-S and the tape peeling test apparatus were used for measurement.

2) 醯 imidization rate

The transparent polyimide phase layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples, and the ruthenium imidization ratio of the transparent polyimide layer was calculated as follows. In addition, the IR absorption spectrum was measured by a Fourier transform infrared (FT-IR) spectroscope (FT/IR 300E, manufactured by JASCO Corporation) to mount a multi-reflective infrared spectrometer (ATR PR0410- M, manufactured by Japan Spectroscopic Corporation).

The IR absorption spectrum of each of the transparent polyimide layers produced in the examples and the comparative examples was measured. Then, the absorption peak height of 1370 cm ^-1 (the CN stretching vibration of the quinone ring) and the absorption peak height of 1500 cm ^-1 (the peak obtained by the C=C stretching vibration of the benzene ring (reference) were calculated for each film. ) The ratio A. On the other hand, a transparent polyimine layer was produced in the same manner as in each of the examples and the comparative examples, and the mixture was heated at 270 ° C for 2 hours or more to be completely imidized. The IR absorption spectrum of each of these films was measured, and the absorption peak height of 1370 cm ^-1 (CN stretching vibration of the quinone ring) was calculated in the same manner as described above with respect to the absorption peak height of 1500 cm ^-1 (C = from the benzene ring) The ratio B of the peak (reference) obtained by the C stretching vibration.

Then, the ratio of the ratio A of the corresponding film to the ratio B (ratio A/ratio B) × 100 (%) was determined, and this was taken as the ruthenium iodization ratio.

3) Solvent residuals

The transparent polyimine layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples, and the solvent residual amount of the transparent polyimide layer was measured. When measuring, will Electric furnace type thermal decomposition furnace (manufactured by Shimadzu Corporation, PYR-2A (thermal decomposition temperature: 320 ° C)) and gas chromatography mass spectrometer (manufactured by Shimadzu Corporation, GC-8A (tubular Uniport HP 80/100 KG-02) ) to determine the amount of solvent contained in the film. At this time, the temperature of the injector and detector of the apparatus was set to 200 ° C, and the column temperature was set to 170 ° C.

4) Total light transmittance

The transparent polyimide layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples, and the total light transmittance of the transparent polyimide layer was measured. Specifically, the measurement was carried out by a light source D65 in accordance with JIS-K-7105 and using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.

5) Fog value

The transparent polyimine layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples, and the haze value of the transparent polyimide layer was measured. Specifically, the measurement was carried out by a light source D65 in accordance with JIS-K-7105 and using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.

6) b value

The transparent polyimine layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples, and the b value of the transparent polyimide layer was measured. For the measurement, a color difference meter (measuring head: CM-2500d, manufactured by Konica Minolta Co., Ltd.) was used, and a C light source, a 2° field of view, and a Specular Component Included (SCI) mode were used. The b value of the transparent polyimide layer on the calibration white plate was measured 3 times. The b value is set to the average of 3 measurements.

7) In-plane phase difference R0

The transparent polyimine layer was peeled off from the transparent polyimide laminate produced in the examples and the comparative examples. The in-plane phase difference of the transparent polyimide layer was measured by the X and Y modes of the photoelastic constant measuring device PEL-3A-102C manufactured by Uniopt. The measurement temperature was set to 25 ° C, and the measurement wavelength was set to 550 nm. Specifically, the refractive index of the polyimide film is measured by a photoelastic constant measuring device, and the direction in which the refractive index is maximized is set to the X axis, and the direction perpendicular to the X axis is set to the Y axis, and the X axis direction is derived. The refractive index nx and the refractive index ny in the Y-axis direction. Further, when the thickness of the film is set to d, the value represented by (nx - ny) × d is taken as the in-plane phase difference.

8) Ten point average roughness of the support substrate

The ten point average roughness of the support substrate used in the examples and the comparative examples was measured in accordance with JIS B0601. At this time, the cut off value was set to 0.25 mm, the measurement length was set to 2.5 mm, and the width direction of the support substrate was measured by a surface roughness/contour shape measuring machine (Surfcom 1400D, manufactured by Tokyo Precision Co., Ltd.). The ten point average roughness.

The abbreviations of the compounds used in the examples and comparative examples are as follows.

[Diamine component]

14BAC: 1,4-bis(aminomethyl)cyclohexane

NBDA: norbornane diamine

ODA: 4,4'-diaminodiphenyl ether

CHDA: trans-1,4-cyclohexanediamine

[tetracarboxylic acid component]

PMDA: pyromellitic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

[solvent]

DMAc: N,N-dimethylacetamide

NMP: N-methyl-2-pyrrolidone

(Synthesis Example 1)

14 BAC 469.4 g (3.3 mol) and DMAc 5761 g were added to a 300 mL five-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube. Powdered BPDA 970.9 g (3.3 mol) was added to the mixture. After the addition of BPDA, the reaction vessel was placed in an oil bath maintained at 120 ° C for 5 minutes. Salt was precipitated about 3 minutes after the addition of BPDA, but then rapidly dissolved. The mixture was further stirred at room temperature for 18 hours to obtain a solution containing a polyimide precursor.

(Synthesis Example 2)

To a 300 mL five-neck separable flask equipped with a thermometer, a stirrer, a nitrogen gas introduction tube, and a dropping funnel, PMDA 39.7 g (0.180 mol) and DMAc 130 g were added and stirred to obtain a slurry of PMDA. On the other hand, a mixed solution of NBDA 27.8 g (0.180 mol) and DMAc 27.8 g was prepared. The mixed solution was added dropwise to the slurry while maintaining the temperature at a constant temperature for 120 minutes. Thereafter, the mixture was stirred at 50 ° C for 5 hours to obtain a solution containing a polyimide precursor.

(Synthesis Example 3)

300 mL five-port separable with thermometer, stirrer and nitrogen inlet tube In a flask, 14 BAC of 14.1 g (0.099 mol), NBDA 1.7 g (0.011 mol), and DMAc 189 g were added and stirred. Powdered BPDA 29.1 g (0.099 mol) and PMDA 2.4 g (0.011 mol) were added to the mixture. After the addition of BPDA and PMDA, the reaction vessel was placed in an oil bath maintained at 120 ° C for 5 minutes. After about 3 minutes after the addition of BPDA and PMDA, salt was precipitated, but it quickly dissolved. The mixture was further stirred at room temperature for 18 hours to obtain a solution containing a polyimide precursor.

(Synthesis Example 4)

To a 300 mL five-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube, ODA 10.0 g (0.050 mol) and DMAc 119 g were added and stirred. In the mixture, a powdery PMDA of 10.9 g (0.050 mol) was added while maintaining a constant temperature. Thereafter, the mixture was stirred at 50 ° C for 5 hours to obtain a solution containing a polyimide precursor.

(Synthesis Example 5)

. Synthesis of proline oligomer solution

To a 300 mL five-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube, 11.4 g (0.100 mol) of CHDA and 116 g of a solvent NMP were added, and the mixture was stirred until the solution became transparent. To this solution, BPDA 27.1 g (0.092 mol) was charged in a powdery state, and the reaction vessel was allowed to stand in an oil bath maintained at 120 ° C for 5 minutes. The salt was temporarily precipitated after loading BPDA. Thereafter, the salt dissolves into a uniform system and the viscosity of the solution increases. After taking out from the oil bath, the mixture was further stirred at room temperature for 18 hours to obtain a solution of a proline oligomer having an amine group derived from CHDA at the end.

. Synthesis of quinone imine oligomer solution

NBDA 11.1 g (0.072 mol) and NMP 94.5 g were added to a 300 mL five-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube, and the mixture was stirred until the solution became transparent. To this solution, 29.28 g (0.100 mol) of BPDA was charged while maintaining the powder state, and the reaction vessel was allowed to stand in an oil bath maintained at 120 ° C for 5 minutes. After the BPDA was loaded, the salt was temporarily precipitated. Thereafter, it was confirmed that the salt re-dissolved as the viscosity increased to become a uniform transparent solution.

A condensing tube and a Dean-Stark type concentrator were attached to the separable flask, and 80.0 g of xylene was added to the reaction solution, and the dehydration heat was carried out at 180 ° C for 4 hours while stirring. Amination reaction. After the reaction, xylene was distilled off to obtain a quinone imine oligomer solution having an acid anhydride structure derived from BPDA at the end.

. Synthesis of block polyphosphonium imide solution

40.0 g of the above proline acid oligomer solution was mixed with 9.99 g of the above-mentioned quinone imine oligomer solution, and made by a high-viscosity material stirring defoaming mixer (Japan Unix Co., Ltd., product name: UM -118) Stir for 10 minutes to obtain a block polyphosphonium imide solution.

(Example 1)

On a polyimide (PI) film (UPILEX 50S (50 μm)) manufactured by Ube Industries, which was fixed on a glass substrate with Kapton tape, using a doctor blade ( The doctor blade) was applied to coat the solution containing the polyimide precursor prepared in Synthesis Example 1. Then, it will contain a glass substrate and a support base. A sample of the material and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours, and was produced on a glass substrate. Transparent polyimine laminate. The resulting transparent polyimide layer had a thickness of 30 μm.

The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.039 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 260 ° C, the total light transmittance was 87%, the in-plane retardation (R0) was 0.8 nm, the oxime imidization ratio was 98%, and the solvent remained. The amount was 0.2% by mass.

(Example 2)

A transparent polyimide polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the oxygen concentration in the inert oven was changed to 5.0%. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.039 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 261 ° C, the total light transmittance was 87%, the in-plane retardation (R0) was 0.8 nm, the oxime imidization ratio was 98%, and the solvent remained. The amount was 0.2% by mass.

(Example 3)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the temperature increase rate was changed to 10 ° C / min. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate is 0.032 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 260 ° C, the total light transmittance was 87%, the in-plane retardation (R0) was 0.7 nm, the oxime imidization ratio was 95%, and the solvent remained. The amount was 0.5% by mass.

(Example 4)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 3 except that the maximum temperature of the inert oven was changed to 280 ° C and the temperature increase rate was set to 2 ° C / min. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.040 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 261 ° C, the total light transmittance was 86%, the in-plane retardation (R0) was 0.7 nm, and the oxime imidization ratio was 100%, which was not detected. Residual solvent.

(Example 5)

On the polyimine film (UPILEX 50S) manufactured by Ube Industries, Inc., which was fixed on a glass substrate by using Kapton tape, the polyimide containing the synthetic polyimide prepared in Synthesis Example 1 was coated with a doctor blade. A solution of the precursor. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 20%, and the temperature was raised to 180 ° C in 75 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 180 ° C for 2 hours. Thereafter, the sample was transferred to a vacuum oven, and the temperature was adjusted to 1 kPa or less by full vacuum, and then the temperature was raised. The pressure-reducing oven was heated from 30 ° C for 60 minutes to 270 ° C (temperature rising rate of 4 ° C / min), and further protected at 270 ° C A transparent polyimide laminate was formed on a glass substrate for 1 hour.

The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.031 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 260 ° C, the total light transmittance was 86%, the in-plane retardation (R0) was 0.5 nm, the oxime imidization ratio was 96%, and the solvent remained. The amount was 0.7% by mass.

(Example 6)

On the polyimine film (UPILEX 50S) manufactured by Ube Industries Co., Ltd., which was fixed on a glass substrate by using Kapton tape, the polyimide contained in Synthesis Example 2 was coated with a doctor blade. A solution of the precursor. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 300 ° C in 135 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 300 ° C for 2 hours to be fabricated on a glass substrate. Transparent polyimine laminate.

The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.029 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 290 ° C, the total light transmittance was 88%, the in-plane retardation (R0) was 0.3 nm, the oxime imidization ratio was 98%, and the solvent remained. The amount was 0.6% by mass.

(Example 7)

The same procedure as in Example 1 was carried out except that the solution containing the polyimine precursor used was changed to the one prepared in Synthesis Example 3, and the temperature increase rate was set to 2 ° C/min. A transparent polyimide laminate was formed on the glass substrate. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide laminate removed from the glass substrate was 0.041 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 266 ° C, the total light transmittance was 88%, the in-plane retardation (R0) was 0.6 nm, the oxime imidization ratio was 96%, and the solvent remained. The amount was 0.3% by mass.

(Reference example 1)

The solution containing the polyimine precursor prepared in Synthesis Example 1 was applied onto an aluminum foil (50 μm) made of Tokai-Alumi on a glass substrate by using Kapton tape. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours, and was produced on a glass substrate. Transparent polyimine laminate. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.19 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 261 ° C, the total light transmittance was 85%, the in-plane retardation (R0) was 1.4 nm, the oxime imidization rate was 99%, and the solvent remained. The amount was 0.1% by mass.

(Reference example 2)

The release agent Zelec UN 0.01 g manufactured by DuPont was formulated in 100 g of the solution containing the polyimine precursor prepared in Synthesis Example 1 (equivalent to 500 ppm relative to the solid content) Polyimide containing exfoliating component A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 8 except that the solution of the precursor was used. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.007 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 260 ° C, the total light transmittance was 85%, the in-plane retardation (R0) was 1.1 nm, the oxime imidization rate was 99%, and the solvent remained. The amount was 0.1% by mass.

(Reference Example 3)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 9 except that the support substrate used was changed to stainless steel (Stainless Steel, SUS) 304 (50 μm). The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.009 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 262 ° C, the total light transmittance was 86%, the in-plane retardation (R0) was 1.2 nm, the oxime imidization rate was 99%, and the solvent remained. The amount was 0.2% by mass.

(Example 8)

The polyimine-containing precursor solution prepared in Synthesis Example 1 was continuously and directly cast and coated on a polyimine film manufactured by Ube Industries, using a die coater (UPILEX 50S (50 μm). In the drying furnace in which the oxygen concentration is controlled to 0.0%, the temperature is gradually increased (the temperature increase rate is equivalent to 5 ° C / min), and the heating is carried out until the maximum temperature is 270 ° C to prepare a transparent polyimide laminate. . The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.039 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 261 ° C, the total light transmittance was 87%, the in-plane retardation (R0) was 2.0 nm, the oxime imidization ratio was 97%, and the solvent remained. The amount was 0.8% by mass.

(Example 9)

A polyimine film (UPILEX 50S (50 μm, Rz=0.03 μm)) manufactured by Ube Industries, Inc., which was fixed on a glass substrate with a Kapton tape, and coated with a doctor blade. A block polyphosphonium imide solution prepared in 5. Next, a sample containing the glass substrate, the support substrate, and the block polyimide film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours, and was produced on a glass substrate. Transparent polyimine laminate. The transparent polyimide layer of the obtained transparent polyimide laminate had a thickness of 30 μm. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.030 kN/m.

The peeled transparent polyimide film has a glass transition temperature (Tg) of 286 ° C, a total light transmittance of 85%, a haze value of 1.0%, a b value of 1.8, and an in-plane retardation (R0) of 0.9 nm. The hydrazine imidation ratio was 98%, and the solvent residual amount was 0.5% by mass.

(Comparative Example 1)

The solution containing the polyimine precursor used was changed to the one prepared in Synthesis Example 4, and the temperature was raised to 300 ° C in 135 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and at 300 ° C A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the film was kept for 2 hours. Removed from the glass substrate The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide laminate was 0.025 kN/m.

The glass transition temperature (Tg) of the transparent polyimide film after peeling was not detected, the total light transmittance was 78%, the in-plane retardation (R0) was 0.9 nm, and the oxime imidization ratio was 95%. The residual amount was 0.9% by mass.

(Comparative Example 2)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the oxygen concentration in the inert oven was changed to 10.0%. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.031 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 259 ° C, the total light transmittance was 79%, the in-plane retardation (R0) was 0.8 nm, the oxime imidization ratio was 97%, and the solvent remained. The amount was 0.5% by mass.

(Comparative Example 3)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the maximum temperature of the inert oven was changed to 230 °C. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.010 kN/m.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 250 ° C, the total light transmittance was 90%, the in-plane retardation (R0) was 0.8 nm, the oxime imidization ratio was 78%, and the solvent remained. The amount was 3.0% by mass.

(Comparative Example 4)

A transparent polyimide laminate was produced on a glass substrate in the same manner as in Example 1 except that the support substrate used was changed to a copper foil (NA-DFF (12 μm)) manufactured by Mitsui Mining and Mining. Attempts were made to peel off the transparent polyimide layer from the copper foil (support substrate) of the transparent polyimide laminate laminated from the glass substrate, but it was not peelable.

(Comparative Example 5)

On a aluminum foil (support substrate; 50 μm) made of Tokai Aluminum fixed on a glass substrate by using Kapton tape, a solution containing the polyimine precursor prepared in Synthesis Example 1 was applied by a doctor blade to 100 g. A solution containing a release component containing a polyimide component having a release component of Zelec UN 0.10 g (corresponding to 5000 ppm relative to a solid content) was prepared. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours. In the transparent polyimide laminate which was taken out from the oven, the transparent polyimide layer on the support substrate was partially aggregated by "uneven coating", and it was confirmed that film formation was difficult.

(Comparative Example 6)

The solution containing the polyimine precursor prepared in Synthesis Example 1 was applied onto a glass substrate directly using a doctor blade. Then, a sample containing the glass substrate and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours, and was produced on a glass substrate. Transparent polyimide layer. The resulting transparent polyimide layer had a thickness of 30 μm.

Attempts have been made to peel off the transparent polyimide layer from the glass substrate, but it is difficult to easily peel off. Therefore, the glass substrate/transparent polyimide layer was immersed in distilled water to peel off the transparent polyimide film from the glass substrate.

The glass transition temperature (Tg) of the peeled transparent polyimide film was 260 ° C, the total light transmittance was 87%, the in-plane retardation (R0) was 0.8 nm, the oxime imidization ratio was 98%, and the solvent remained. The amount was 0.1% by mass.

(Comparative Example 7)

A polyimine film (UPILEX 50S (50 μm, Rz=0.03 μm)) manufactured by Ube Industries, Inc., which was fixed on a glass substrate with a Kapton tape, and coated with a doctor blade. A solution containing a polybendimimine precursor prepared in 1. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 200 ° C in 85 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 200 ° C for 2 hours. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.008 kN/m.

The peeled transparent polyimide film was fixed to the entire circumference of a stainless steel metal frame by Kapton tape. This was placed in an inert oven, and the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 250 ° C in 110 minutes from 30 ° C (temperature up rate was 2 ° C / min). Then, it was kept at 250 ° C for 2 hours to obtain a transparent polyimide film having a film thickness of 30 μm. The obtained transparent polyimide film had a glass transition temperature (Tg) of 258 ° C, a total light transmittance of 87%, a haze value of 3.7%, a b value of 0.9, and an in-plane retardation (R0) of 80 nm. The imidization rate is 88%, solvent The residual amount was 1.5% by mass.

(Comparative Example 8)

A polyimine film (UPILEX 50S (50 μm, Rz=0.03 μm)) manufactured by Ube Industries, Inc., which was fixed on a glass substrate with a Kapton tape, and coated with a doctor blade. A solution containing a polybendimimine precursor prepared in 1. Then, a sample containing the glass substrate, the support substrate, and the polyimide precursor film was placed in an inert oven. Thereafter, the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours, and was produced on a glass substrate. Transparent polyimine laminate. The peeling strength of the interface of the support substrate/transparent polyimide layer of the transparent polyimide layer laminated body removed from the glass substrate was 0.039 kN/m.

The peeled film was fixed to the entire circumference of a stainless steel metal frame by Kapton tape. This was placed in an inert oven, and the oxygen concentration in the inert oven was controlled to 0.0%, and the temperature was raised to 270 ° C in 120 minutes from 30 ° C (temperature rising rate was 2 ° C / min), and further maintained at 270 ° C for 2 hours. A transparent polyimide film having a film thickness of 30 μm was obtained. The obtained transparent polyimide film had a glass transition temperature (Tg) of 260 ° C, a total light transmittance of 88%, a haze value of 1.5%, a b value of 0.8, and an in-plane retardation (R0) of 12 nm. The imidization ratio was 100%, and no solvent was detected.

As shown in Table 1, the polyimide precursor was heated at a temperature higher than the glass transition temperature of the obtained transparent polyimide layer (Examples 1 to 9 and Reference Examples 1 to 1) 3. In Comparative Example 2, Comparative Example 6, and Comparative Example 8), the residual amount of the solvent was 1.0% by mass or less, and the ruthenium iodide ratio was also 95% or more. On the other hand, when heating was performed at a temperature lower than the glass transition temperature of the obtained transparent polyimide layer (Comparative Example 3 Comparative Example 7), the residual amount of the solvent was 3.0% by mass, and the ruthenium was imidized. The rate is less than 90%, and the drying of the solvent or the ruthenium imidization of the polyimide precursor is insufficient.

Further, the polyimide substrate was heated at a temperature higher than the glass transition temperature on the support substrate to obtain a polyimide film (Examples 1 to 9, Reference Example 1 to Reference Example 3, Comparative Example 1, and Comparative Example 2). In the case of Comparative Example 6), the in-plane retardation was 10 nm or less. On the other hand, after heating on the support substrate at a temperature lower than the glass transition temperature, the polyimide film is peeled off from the support substrate, and it is fixed to the metal frame and further heated (Comparative Example) 7), or heating on the support substrate at a temperature above the glass transition temperature, the polyimine film is peeled off from the support substrate, fixed on the metal frame and further at a temperature above the glass transition temperature In the case of heating (Comparative Example 8), the in-plane retardation exceeded 10 nm. If the in-plane phase difference exceeds 10 nm, the use as an optical film is limited.

Further, when the support substrate was set to a polyimide film (Examples 1 to 9, Comparative Example 1 to Comparative Example 3, Comparative Example 7, and Comparative Example 8), the substrate was peeled off from the support substrate. The peel strength at the time of the polyimide layer was 0.041 kN/m or less, and the peelability of the transparent polyimide layer was good.

On the other hand, when the support substrate was set to an aluminum substrate, the peel strength when the transparent polyimide layer was peeled off from the support substrate was 0.19 kN/m, which was relatively high (Reference Example 1). On the other hand, even when the support substrate is set to an aluminum substrate, if the release agent is contained in the solution containing the polyimide precursor (Reference Example 2), the peel strength is remarkably lowered. However, if the amount of the releasing agent is too large, the solution containing the polyimine precursor cannot be uniformly applied (Comparative Example 5). In the case where the SUS plate is used as the support substrate and the release agent is contained in the solution containing the polyimide precursor, the peeling strength at the time of peeling off the transparent polyimide layer from the support substrate is low, and the peeling property is low. Good (Reference Example 3).

On the other hand, in the case where the support substrate is set to a copper foil and the solution containing the polyimide precursor does not contain a release agent (Comparative Example 4), the support substrate and the transparent polyimide layer are The peel strength is high and the peeling cannot be performed. Further, when the support substrate was set as the glass substrate (Comparative Example 6), the peeling strength of the support substrate and the transparent polyimide layer was high, and the transparent polyimide layer could not be peeled off without being immersed in water.

Further, when the support substrate is an aluminum substrate or a SUS plate, the ten-point average roughness (Rz) of the surface of the support substrate is rough, and the transparent polyimide layer formed on the support substrate is fogged. The value tends to become high (Reference Example 1 to Reference Example 3).

Further, in the case where the main chain of the polyimine contains an alicyclic group, the total light transmittance is high (Comparative Examples 1 to 9 and Reference Example 1 to Reference Example 3, Comparative Example 3, and Comparative Example 6) Example 8). On the other hand, the wholly aromatic transparent polyimide film (Comparative Example 1) had a low total light transmittance. In addition, even if the main chain of the polyimine contains an alicyclic group, the oxygen concentration in the solution containing the polyimide precursor is increased. In the case of 5 vol% (Comparative Example 2), the total light transmittance was lowered. It is presumed that the polyimine is oxidized upon heating and the film is yellowed.

[Industrial availability]

The transparent polyimide film obtained from the transparent polyimide laminate of the present invention has a high total light transmittance and a small in-plane retardation. Therefore, it can be applied to a substrate for a touch panel, a substrate for a color filter, a substrate for a liquid crystal cell, and a substrate for a flexible display such as an organic EL display substrate.

1‧‧‧ Polyimine precursor film

1'‧‧‧Transparent Polyimine Layer

10‧‧‧heating furnace

11‧‧‧Support substrate

20‧‧‧ Coating device

21‧‧‧Ring belt

30‧‧‧ Roll body

Claims (18)

A method for producing a transparent polyimide polyimide laminate, which is a method for producing a transparent polyimide polyimide laminate comprising a support substrate and a transparent polyimide layer laminated on the support substrate; a step of applying a solution containing a polyimide precursor to the support substrate, wherein the solution containing the polyimide precursor contains a polyimine obtained by reacting a tetracarboxylic acid component and a diamine component a precursor and a solvent; and b) heating the polyimide film of the coating film containing the solution of the polyimine precursor-containing solution at a temperature above the glass transition temperature of the transparent polyimide layer And the glass transition temperature of the transparent polyimide layer is 260 ° C or higher, the total light transmittance is 80% or more, the haze value is 5% or less, and the absolute value of b in the L*a*b color system is absolute. When the value is 5 or less and the in-plane retardation is 10 nm or less, the peel strength when the transparent polyimide layer is peeled off from the support substrate is 0.005 kN/m to 0.20 kN/m. The method for producing a transparent polyimide laminate according to claim 1, wherein the support substrate is a flexible substrate. The method for producing a transparent polyimine laminate according to claim 1, wherein the solution containing the polyimide precursor further contains a release agent. The method for producing a transparent polyimide laminate according to claim 1, wherein the oxygen concentration in the atmosphere is set to 5 vol% or less in a temperature range of more than 200 ° C in the step b). The method for producing a transparent polyimine laminate according to claim 1, wherein the atmosphere is decompressed in a temperature range of more than 200 ° C in the above step b). The method for producing a transparent polyimine laminate according to claim 1, wherein the step b) is heating from 150 ° C to more than 200 ° C to heat the polyimide precursor film. The step of setting the average temperature increase rate in the temperature range of 150 ° C to 200 ° C in the above step b) is set to 0.25 ° C / min to 50 ° C / min. The method for producing a transparent polyimine laminate according to claim 1, wherein the polyimine precursor is a compound obtained by reacting a tetracarboxylic acid component (A) with a diamine component (B). The tetracarboxylic acid component (A) contains one or more kinds of tetracarboxylic dianhydride represented by the following formula (a), and the diamine component (B) contains a compound selected from the following formula (b-1). One or more diamines in the group consisting of the compounds represented by formula (b-3), In the formula (a), R ¹ represents a tetravalent group having 4 to 27 carbon atoms, and represents an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensation. a cyclic aromatic group, or a non-condensed polycyclic aliphatic group in which a cyclic aliphatic group is directly or by a crosslinker, or an aromatic group is directly or by a crosslinker Non-condensed polycyclic aromatic group, The method for producing a transparent polyimine laminate according to claim 7, wherein the polyimine precursor has a repeating unit represented by the following formula (1), in the formula (I) The 1,4-bismethylenecyclohexane skeleton (X) includes a trans form represented by the formula (X1) and a cis form represented by the formula (X2), and the content ratio of the trans form to the cis form is 60% ≦ trans-body ≦ 100%, 0% ≦ 式 body ≦ 40%, of which trans-body + cis-form = 100%, In the formula (I), R ¹⁰ represents a tetravalent group having 4 to 27 carbon atoms, and represents an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensation. a cyclic aromatic group, or a non-condensed polycyclic aliphatic group in which a cyclic aliphatic group is directly or by a crosslinker, or an aromatic group is directly or by a crosslinker Non-condensed polycyclic aromatic groups. The method for producing a transparent polyimine laminate according to claim 1, wherein the polyimine precursor is a block polyamine having a polyphthalic acid block and a polyimine block. The hydrazide imine, the poly phthalic acid block is composed of a repeating structural unit represented by the following general formula (G), and the polyfluorene imide block is a repeat represented by the following general formula (H) Constructed by structural units, In the general formula (G) and the general formula (H), R ⁶ and R ⁸ are each independently a tetravalent group having 4 to 27 carbon atoms, and represent an aliphatic group, a monocyclic aliphatic group, or a condensed polycyclic fat. a group-based, monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group represented by a cyclic aliphatic group directly or by a crosslinker, or an aromatic a non-condensed polycyclic aromatic group which is bonded to each other directly or by a crosslinker; in the formula (H), R ⁷ is a divalent group having a carbon number of 4 to 51, and is an aliphatic group or a single ring. An aliphatic group (excluding 1,4-cyclohexylene), a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensed polycyclic aromatic group, or a cyclic aliphatic group directly or borrowed A non-condensed polycyclic aliphatic group which is linked to each other by a crosslinker, or a non-condensed polycyclic aromatic group which is an aromatic group directly or by a crosslinker. The method for producing a transparent polyimide laminate according to claim 1, wherein the step a) is to apply the solution containing the polyimide precursor to the support substrate rolled up from the roll. And the step b) includes the step of winding the transparent polyimide polyimide laminate onto the roll after heating the polyimine precursor film. A transparent polyimine laminate obtained by the method for producing a transparent polyimide laminate according to claim 1 of the patent application. An optical film obtained by peeling off a transparent polyimide layer from a support substrate of a transparent polyimide laminate according to claim 11 of the patent application. A method for producing a transparent polyimide film, comprising: peeling off a transparent polyimide layer from a support substrate of a transparent polyimide laminate according to claim 11 to obtain a transparent polyimide The step of the membrane. A method of producing a flexible member, comprising: forming a component on the transparent polyimide layer of the transparent polyimide layer according to claim 11; and forming the component The step of peeling off the transparent polyimide layer from the support substrate. A method of producing a flexible member, comprising the step of forming an element on a transparent polyimide film obtained by the production method according to claim 11 of the patent application. A touch panel display obtained by the method of manufacturing a flexible member according to claim 14 or 15. A liquid crystal display obtained by the method for producing a flexible member according to claim 14 or 15. An organic EL display obtained by the method of producing a flexible member according to claim 14 or 15.