JP7070128B2 - A method for manufacturing a laminate, a polyimide film, a surface material for a display, a touch panel member, a liquid crystal display device, an organic electroluminescence display device, a polyimide film, a method for manufacturing a laminate, and a method for manufacturing a surface material for a display. - Google Patents

Description

The present invention relates to a laminate, a polyimide film, a surface material for a display, a touch panel member, a liquid crystal display device, an organic electroluminescence display device, a method for manufacturing a polyimide film, a method for manufacturing a laminate, and a method for manufacturing a surface material for a display.

Generally, a polyimide resin is a highly heat-resistant resin obtained by subjecting a polyamic acid (polyamic acid) obtained by a condensation reaction between an aromatic tetracarboxylic acid anhydride and an aromatic diamine to a dehydration ring closure reaction (imidization reaction). ..
Since the polyimide resin is generally colored yellow or brown, it has been difficult to use it in fields requiring high transparency such as display applications and optical applications.

In recent years, research for obtaining a polyimide having high transparency has been advanced, and it is being studied to apply a polyimide having improved transparency to a display member.
The polyimide film is generally produced by applying a polyamic acid (polyamic acid) solution or a polyimide solution, which is a polyimide precursor, onto a support such as an endless belt or a drum and drying the film.
For example, Patent Document 1 describes, as a method for efficiently producing a polyimide film having excellent heat resistance, transparency, surface smoothness, and optical properties, with a mirror surface gloss of a predetermined value or more and a rough surface. The polyimide-based resin B layer is laminated on the surface of the solvent-soluble resin A layer laminated on the surface of the metal material having a (Rz) of less than or equal to a predetermined value, and the polyimide-based resin B layer is obtained from the obtained metal laminate B. A method of peeling to obtain a polyimide-based film is disclosed.

International Publication No. 2015/186594 Pamphlet

As described above, the polyimide film is superior in heat resistance and the like as compared with other resin films, and is a material that is particularly attracting attention in the field of electronics.
Above all, the transparent polyimide film with improved transparency is expected to be applied to liquid crystal displays, organic EL displays, etc. as a material to replace glass, and was developed with the aim of applying it to flexible devices that take advantage of the characteristics of resin films. Is underway.

A polyimide film is generally used by laminating a functional layer such as a hard coat layer on the surface thereof. For example, when a polyimide film is used for display applications or optical applications, the polyimide film is often arranged on the surface side. Therefore, a laminate in which a functional layer such as the above-mentioned hard coat layer is laminated on the surface of the polyimide film. It is commonly used as.
However, the polyimide film may not always have sufficient adhesion to the functional layer, and in this case, the quality as a laminate is deteriorated, or a part of the functional layer is made of the polyimide film. There is a problem that it peels off and hinders stable production.

Further, when the laminate of the polyimide film is used in a field such as a display application or an optical application, it is required to improve the appearance as the laminate. However, fine streaks may be generated on the surface of the polyimide film in a predetermined direction, and when such streaks appear on the surface of the polyimide film, the appearance of the laminated body is inferior.
Further, when the laminate of the polyimide film is used in a field such as a display application or an optical application, improvement of its optical characteristics is also required.

The present invention has been made in view of the above problems, and is a laminate in which the polyimide film and the functional layer have excellent adhesion, the appearance is good, and the optical characteristics are excellent, and the polyimide used in the laminate. A method for producing a laminate including a film, a surface material for a display which is the polyimide film, a touch panel member, a liquid crystal display device, an organic electroluminescence display device, a method for producing the polyimide film, and a method for producing the polyimide film. An object of the present invention is to provide a method for producing a surface material for a liquid crystal display, which comprises a method for producing the polyimide film or a method for producing the laminate.

(Laminated body)
The laminate of the present invention is a long polyimide film, and when one surface of the polyimide film is used as the first surface, the polyimide is viewed in a field of 700 μm × 700 μm in the first surface. Of the first region (A1) arbitrarily extracted so as to extend in a direction orthogonal to the longitudinal direction of the film and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The average value (Wa1 _ave ) of the surface waviness (Wa1) and the width extending in the direction along the longitudinal direction of the polyimide film and perpendicular to the longitudinal direction are narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) arbitrarily extracted so as to be 20 nm or less, and is in the first plane. It has a polyimide film having a surface roughness (Sa) of 1 nm or more and 10 nm or less in a field of 71 μm × 95 μm, and a functional layer laminated in contact with the first surface of the polyimide film.

In the laminated body of the present invention, the functional layer may be a hard coat layer.

In the laminate of the present invention, the hard coat layer contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound from the viewpoint of improving the adhesion between the polyimide film and the functional layer. preferable.

In the laminate of the present invention, the radically polymerizable compound is a compound having two or more (meth) acryloyl groups in one molecule, and the cationically polymerizable compound has at least one molecule of an epoxy group and an oxetanyl group. A compound having two or more of them is preferable from the viewpoint of improving the adhesion between the polyimide film and the functional layer.

In the laminated body of the present invention, it is preferable that the laminated body has a haze value of 2.0 or less according to JIS K-7105 from the viewpoint of improving optical characteristics.

(Polyimide film)
The polyimide film of the present invention has a long shape, and is a polyimide film for forming a functional layer for forming a functional layer on the first surface when one surface is used as the first surface. In a 700 μm × 700 μm field of view in the first plane, the polyimide film extends in a direction orthogonal to the longitudinal direction, and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) arbitrarily extracted so as to be, extends in the direction along the longitudinal direction of the polyimide film, and is orthogonal to the longitudinal direction. Difference from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) arbitrarily extracted so that the width in the direction to be formed is narrower than the length in the longitudinal direction (Wa1 _ave- ). Wa2 _ave ) is 20 nm or less, and the surface roughness (Sa) in the field of view of 71 μm × 95 μm in the first plane is 1 nm or more and 10 nm or less.

In the polyimide film of the present invention, a haze value based on JIS K-7105 is preferably 2.0 or less from the viewpoint of improving optical characteristics.

(Surface material for display)
The surface material for a display of the present invention is the polyimide film of the present invention or the laminate of the present invention.

The surface material for a display of the present invention may be for a flexible display.

(Touch panel member)
The touch panel member of the present invention is electrically formed by the polyimide film of the present invention, a transparent electrode composed of a plurality of conductive portions arranged on one surface side of the polyimide film, and at least one side of an end portion of the conductive portion. It comprises a plurality of fetch lines to be connected.

The touch panel member of the present invention may have a functional layer laminated in contact with the first surface of the polyimide film.

(Liquid crystal display device)
The liquid crystal display device of the present invention has a liquid crystal display unit having a liquid crystal layer formed between substrates arranged so as to face each other, and the polyimide film of the present invention arranged on one side of the liquid crystal display unit. ..

The liquid crystal display device of the present invention may have a functional layer laminated in contact with the first surface of the polyimide film.

(Organic electroluminescence display device)
The organic electroluminescence display device of the present invention has an organic electroluminescence display unit having an organic electroluminescence layer formed between substrates arranged opposite to each other, and the book arranged on one side of the organic electroluminescence display unit. It has the polyimide film of the present invention.

The organic electroluminescence display device of the present invention may have a functional layer laminated in contact with the first surface of the polyimide film.

(Manufacturing method of polyimide film)
In the method for producing a polyimide film of the present invention, the surface of a long support is polished so as to extend in a direction orthogonal to the longitudinal direction of the support in a 700 μm × 700 μm field of view of the surface of the support. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (B1) arbitrarily extracted so that the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. A second region (arbitrarily extracted so that the width extending along the longitudinal direction of the support and the width in the direction orthogonal to the longitudinal direction is narrower than the length in the longitudinal direction). The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface swell (Wa2) of B2) is set to 20 nm or less, and the surface roughness (Sa) of the surface of the support in a field of view of 71 μm × 95 μm. ) Is 1 nm or more and 10 nm or less, and
A polyimide precursor composition containing a polyimide precursor and an organic solvent is applied to the surface of the support to form a coating film of the polyimide precursor composition, or a polyimide composition containing a polyimide and an organic solvent. Is applied to the surface of the support to form a coating film of the polyimide composition, and the organic solvent is removed from the coating film of the polyimide precursor composition and contained in the coating film of the polyimide precursor composition. It comprises a step of forming a polyimide film by imidizing the polyimide precursor or removing the organic solvent from the coating film of the polyimide composition.

In the method for producing a polyimide film of the present invention, it is preferable that the polyimide film has a haze value of 2.0 or less in accordance with JIS K-7105 from the viewpoint of improving optical characteristics.

(Manufacturing method of laminated body)
The method for producing a laminate of the present invention includes a step of preparing a polyimide film obtained by the method for producing a polyimide film of the present invention and a surface for forming a functional layer on the surface of the polyimide film on the side in contact with the support. It includes a step of forming a coating film of the composition and a step of curing the coating film.

In the method for producing a laminated body of the present invention, the composition for forming a functional layer may be a composition for forming a hard coat layer.

In the method for producing a laminate of the present invention, the composition for forming a hard coat layer must contain at least one of a radically polymerizable compound and a cationically polymerizable compound to ensure adhesion between the polyimide film and the functional layer. It is preferable from the viewpoint of improvement.

(Manufacturing method of surface material for display)
The method for manufacturing a surface material for a display of the present invention includes a step of manufacturing a polyimide film by the manufacturing method of the present invention, or a step of manufacturing a laminate by the manufacturing method of the present invention.

According to the present invention, the polyimide film and the functional layer have excellent adhesion, a good appearance, and an excellent optical property, a polyimide film used for the laminate, the laminate, or the polyimide film. A surface material for a display, a touch panel member, a liquid crystal display device, an organic electroluminescence display device, a method for manufacturing the polyimide film, a method for manufacturing a laminate including the method for manufacturing the polyimide film, and a method for manufacturing the polyimide film or the above. It is possible to provide a method for manufacturing a surface material for a display including a method for manufacturing a laminate.

FIG. 1 is a plan view for explaining the structure of the polyimide film included in the laminate according to the present invention. FIG. 2 is an interference fringe image of a polyimide film acquired by a scanning white interference microscope. FIG. 3 shows the interference fringe image shown in FIG. 2 extending in a direction along the longitudinal direction of the polyimide film to be measured, and the width in the direction orthogonal to the longitudinal direction is wider than the length in the longitudinal direction. It is an image extracted so as to be narrow. FIG. 4 is a schematic plan view showing an example of the touch panel member 10 of the present invention. FIG. 5 is a cross-sectional view taken along the line AA'of the touch panel member 10 shown in FIGS. 4 (A) and 4 (B). 6 (A) is a schematic plan view of the first laminated body 201, and FIG. 6 (B) is a schematic plan view of the second laminated body 202. FIG. 7 is shown in FIGS. 6 (A) and 6 (B) of the touch panel member 20 formed by laminating the laminated body 201 shown in FIG. 6 (A) and the laminated body 202 shown in FIG. 6 (B). It is sectional drawing at the position shown by the line AA'. FIG. 8 is a schematic cross-sectional view showing an example of the liquid crystal display device 100 of the present invention. FIG. 9 is a schematic cross-sectional view showing an example of the liquid crystal display device 200 of the present invention. FIG. 10 is a schematic cross-sectional view showing an example of the organic electroluminescence display device 300 of the present invention. It is a schematic sectional drawing which shows an example of the organic electroluminescence display device 400 of this invention.

I. Laminate
The laminate of the present invention is a long polyimide film, and when one surface of the polyimide film is used as the first surface, the polyimide is viewed in a field of 700 μm × 700 μm in the first surface. Of the first region (A1) arbitrarily extracted so as to extend in a direction orthogonal to the longitudinal direction of the film and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The average value (Wa1 _ave ) of the surface waviness (Wa1) and the width extending in the direction along the longitudinal direction of the polyimide film and perpendicular to the longitudinal direction are narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) arbitrarily extracted so as to be 20 nm or less, and is in the first plane. It has a polyimide film having a surface roughness (Sa) of 1 nm or more and 10 nm or less in a field of 71 μm × 95 μm, and a functional layer laminated in contact with the first surface of the polyimide film.

In the following description, a region extending in a direction orthogonal to the longitudinal direction of the polyimide film and having a width in the longitudinal direction narrower than a length in a direction orthogonal to the longitudinal direction is defined as "in the longitudinal direction". The first region (A1) extending in the orthogonal direction is called "(see FIG. 1).
Further, in the following description, a region extending in a direction along the longitudinal direction of the polyimide film and having a width in a direction orthogonal to the longitudinal direction narrower than the length in the longitudinal direction is referred to as "longitudinal direction". The second region (A2) extending in the direction along the above line (see FIG. 1).

According to the present invention, when one surface of the polyimide film is used as the first surface, it is arbitrarily extracted in a field of view of 700 μm × 700 μm in the first surface, and “extended in a direction orthogonal to the longitudinal direction”. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the "existing first region (A1)" and the second "extending in the longitudinal direction" arbitrarily extracted in the 700 μm × 700 μm visual field. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the region (A2) is 20 nm or less, and the surface in the field of view of 71 μm × 95 μm in the first plane. By having a polyimide film having a roughness (Sa) of 1 nm or more and 10 nm or less, the first surface of the polyimide film and the functional layer have excellent adhesion, the appearance is good, and the optical characteristics are improved. An excellent laminate can be obtained.

In FIG. 1, the "first region extending in the direction orthogonal to the longitudinal direction" of the polyimide film 1 is indicated by A1, and the "second region extending in the longitudinal direction" is indicated by A2. show.

Conventionally, the polyimide film has been required to have surface smoothness. On the other hand, when a functional layer such as a hard coat layer is laminated on the surface of the polyimide film, if the surface smoothness of the polyimide film is too high, sufficient adhesion between the polyimide film and the functional layer cannot be obtained. There are problems that a part of the functional layer is peeled off from the polyimide film, the quality of the laminated body is deteriorated, and stable production is hindered.
In order to improve the adhesion between the polyimide film and the functional layer, it is effective to slightly reduce the surface smoothness of the adhesive surface of the polyimide film with respect to the functional layer. The surface smoothness of the polyimide film is controlled by controlling the polishing state of the support to which the polyamic acid (polyamic acid) solution or the polyimide solution, which is the polyimide precursor solution, is applied in the manufacturing process to improve the surface smoothness of the support. It can be improved or lowered by adjusting.
However, when a polyimide film is produced by applying a polyamic acid solution or a polyimide solution on a support having reduced surface smoothness as described above, the surface of the polyimide film is covered with the above-mentioned polyamic acid solution or the polyimide solution. Fine streaks are likely to be formed so as to extend in the direction along the flow direction of the support coated with the polyimide solution. When such a streak becomes apparent on the surface of the polyimide film, the appearance of the polyimide film or its laminate is inferior.
Further, when a polyimide film is produced by applying a polyamic acid solution or a polyimide solution on a support having reduced surface smoothness as described above, the surface state of the support is reflected. The haze value of the polyimide film may increase, and the optical properties of the laminate may deteriorate.

The laminate according to the present invention is an arbitrary polyimide film constituting the laminate, when one surface of the polyimide film is used as the first surface, in a field of view of 700 μm × 700 μm in the first surface. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the extracted "first region (A1) extending in the direction orthogonal to the longitudinal direction" and the "700 μm × 700 μm" field of view were arbitrarily extracted. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the "second region (A2) extending in the longitudinal direction" is 20 nm or less, and the first By having a polyimide film having a surface roughness (Sa) of 1 nm or more and 10 nm or less in a field of view of 71 μm × 95 μm in one plane, high adhesion can be obtained between the polyimide film and the functional layer, and , The appearance of streaks on the surface of the polyimide film is suppressed, a good appearance can be obtained in the laminated body, and excellent optical characteristics can be obtained.

1. 1. Main Configuration of Laminates The laminate of the present invention will be described in detail below.
The laminate of the present invention has the above-mentioned long polyimide film and a functional layer laminated in contact with the first surface of the polyimide film.
The laminate of the present invention may be one in which the functional layer is in contact with and laminated only on the first surface of the polyimide film, or the functional layer is in contact and laminated on both sides of the polyimide film. It may be a thing.

2. 2. Polyimide film The polyimide film possessed by the laminate of the present invention is a long polyimide film, and when one surface of the polyimide film is used as the first surface, 700 μm × 700 μm in the first surface. The average value (Wa1 _ave ) of the surface swell (Wa1) of the "first region (A1) extending in the direction orthogonal to the longitudinal direction" arbitrarily extracted in the field of view of No. 1 and the field of view of 700 μm × 700 μm. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the "second region (A2) extending along the longitudinal direction" extracted in the above is 20 nm or less. Moreover, the surface roughness (Sa) in the field of view of 71 μm × 95 μm in the first plane is 1 nm or more and 10 nm or less.

In the following description, "surface waviness (Wa)" and "surface roughness (Sa)" refer to values determined by measurement as follows.
The terms used in the following explanations of "method for measuring surface waviness" and "method for measuring surface roughness" are based on the provisions of ISO 25178.

(Measuring method of surface waviness)
Using a scanning white interference microscope (for example, "Vert Scan" manufactured by Hitachi High-Tech Science Co., Ltd.), an image of interference fringes in a region including a 700 μm × 700 μm visual field region is acquired on the surface of the object to be measured (for example). (See FIG. 2), the original surface of the object to be measured is determined from the interference contrast fringe image in the field of view of 700 μm × 700 μm in the acquired image.
Next, a surface filter (S-filter) treatment is performed from the obtained original surface to obtain a foundation surface, and then a predetermined surface filter treatment is performed on the foundation surface to obtain a contour curved surface (waviness curved surface). demand.
Next, a predetermined region is defined for the contour curved surface (waviness curved surface), the average plane of the defined predetermined region is the XY plane, the height direction is the Z axis, and the contour curved surface (waviness curved surface) is Z = f1 (waviness curved surface). When expressed by x, y), the value given by the following formula (1) expressed in nm units is called "surface waviness (Wa)".

(Measuring method of surface roughness)
Using a scanning white interference microscope (for example, "Vert Scan" manufactured by Hitachi High-Tech Science Co., Ltd.), an image of interference fringes in a region including a viewing area of 71 μm × 95 μm is acquired and acquired on the surface of the object to be measured. The original surface of the object to be measured is determined from the interference fringe image in the field of view of 71 μm × 95 μm in the image.
Next, a surface filter (S-filter) treatment is performed from the obtained original surface to obtain a foundation surface, and then an L-filter treatment is performed on the foundation surface to obtain a contour curved surface (roughness curved surface). Find a certain SL plane.
Next, a predetermined region is defined for the SL plane (contoured curved surface (roughness curved surface)), the average plane of the defined predetermined region is the XY plane, and the height direction is the Z axis, and the SL plane is defined. When (contour curved surface (roughness curved surface)) is expressed by Z = f2 (x, y), the value given by the following equation (2) expressed in nm units is called "surface roughness (Sa)". ..

The polyimide film of the laminate of the present invention has a first surface having a surface roughness (Sa) of 1 nm or more and 10 nm or less in a field of view of 71 μm × 95 μm.

Since the surface roughness (Sa) of at least the first surface of the polyimide film is 1 nm or more, the polyimide film has excellent adhesion to a functional layer formed in contact with the first surface of the polyimide film. Has. The surface roughness (Sa) of the first surface is preferably 1.1 nm or more, and more preferably 1.2 nm or more, from the viewpoint of improving the adhesion of the polyimide film to the functional layer.
Further, since the surface roughness (Sa) of at least the first surface of the polyimide film is 10 nm or less, an excessive increase in haze value in the polyimide film is suppressed. Therefore, excellent optical characteristics can be obtained as a laminated body. The surface roughness (Sa) of the first surface is preferably 6 nm or less, and more preferably 4 nm or less, from the viewpoint of suppressing an increase in the haze value of the polyimide film.
The polyimide film has a surface roughness (Sa) of 1.2 nm or more and 4 nm or less in a field of view of 71 μm × 95 μm from the viewpoint of improving the adhesion to the functional layer and suppressing the increase in the haze value. It is preferable to have.

As described above, the polyimide film possessed by the laminate of the present invention is a long polyimide film, which is arbitrarily extracted in the field of view of 700 μm × 700 μm in the first plane, and is “direction orthogonal to the longitudinal direction”. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the "first region (A1) extending in" and the "extending in the longitudinal direction" arbitrarily extracted in the 700 μm × 700 μm field of view. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the "two regions (A2)" is 20 nm or less.

Generally, the surface of the long polyimide film has a direction along the flow direction of the support coated with the polyamic acid solution or the polyimide solution in the manufacturing process, that is, a direction along the longitudinal direction of the long polyimide film. In addition, streaks tend to occur. In such a streak, the surface waviness (Wa1) of the first region (A1) extending in the direction orthogonal to the longitudinal direction is increased, and the average value (Wa1 _ave ) of the surface waviness (Wa1) is increased. As the difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) extending in the longitudinal direction increases, it becomes apparent on the surface of the polyimide film. It will be easier.
The cause of the increase in the difference (Wa1 _ave -Wa2 _ave ) between the average value (Wa1 _ave ) of the surface waviness (Wa1) and the average value (Wa2 _ave ) of the surface waviness (Wa2) is the polyimide film after film formation. In order to slightly increase the surface roughness of the support, the polishing state of the support to which the polyimide precursor solution or the polyimide solution is applied is adjusted to slightly reduce the surface smoothness of the support. The overall shape is reflected in the polyimide film after film formation.
The polyimide film of the laminate of the present invention has an average value (Wa1 _ave ) of surface waviness (Wa1) of the first region (A1) extending in a direction orthogonal to the longitudinal direction and extending in a direction along the longitudinal direction. Since the difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the existing second region (A2) is 20 nm or less, the surface roughness is kept in the above-mentioned range. , The streaks on the surface of the film are said to be inconspicuous.
From the viewpoint of suppressing the generation of streaks on the surface of the polyimide film, the average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) and the surface waviness (Wa2) of the second region (A2). The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of) is preferably 15 nm or less, more preferably 10 nm or less, and further preferably 5 nm or less.
Further, from the viewpoint of suppressing deterioration of the appearance of the surface of the polyimide film, the average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) and the surface waviness of the second region (A2). The difference (Wa1 _ave − Wa2 _ave ) from the average value (Wa2 _ave ) of (Wa2) is preferably −20 nm or more, and more preferably −10 nm or more.

The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) extending in the direction orthogonal to the longitudinal direction of the polyimide film, and the second extending in the longitudinal direction of the polyimide film. The average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) can be calculated as follows.
First, a scanning white interference microscope (for example, "Vert Scan" manufactured by Hitachi High-Tech Science Co., Ltd.) is used to acquire an interference fringe image of a region including a visual field region of 700 μm × 700 μm on the surface of the polyimide film (for example). , See FIG. 2).
Next, in the interference fringe image in the field of view of 700 μm × 700 μm in the acquired image, it extends in the direction orthogonal to the longitudinal direction of the polyimide film to be measured, and the width in the longitudinal direction is orthogonal to the longitudinal direction. The first region (A1) is arbitrarily extracted so as to be narrower than the length in the direction to be used.
Next, the raw surface of the polyimide film was determined from the interference fringe image of the first region (A1) arbitrarily extracted, and from the basic surface of the obtained raw surface, the procedure described in the above-mentioned method for measuring surface waviness was used. , Find the contour curved surface (waviness curved surface). Next, from the obtained contour curved surface (waviness curved surface), the surface waviness (Wa1) of the first region (A1) is calculated by the procedure described in the above-mentioned method for measuring surface waviness.
Next, the position where the first region (A1) is extracted from the above-mentioned interference fringe image in the field of 700 μm × 700 μm is extracted by shifting it from the previous extraction position in the longitudinal direction of the polyimide film to be measured. The surface waviness (Wa1) of the first region (A1) is calculated by repeating the same procedure as above for the extracted interference fringe image of the first region (A1).
The above-mentioned step of calculating the surface waviness (Wa1) of the first region (A1) was repeated a plurality of times while shifting the extraction position of the first region (A1), and the first region (A1) obtained in each was repeated. By calculating the average value of the surface undulation (Wa1), the average value (Wa1 _ave ) of the surface undulation (Wa1) of the first region (A1) is obtained.

Further, the surface waviness (Wa2) of the second region (A2) extending in the longitudinal direction of the polyimide film is the average value (Wa1) of the surface waviness (Wa1) of the first region (A1) described above. The polyimide film to be measured in the interference fringe image in the 700 μm × 700 μm visual field in the interference fringe image (for example, see FIG. 2) of the region including the 700 μm × 700 μm visual field region acquired at the time of calculation of _ave ). The second region (A2) is arbitrarily extracted so that the width extending along the longitudinal direction of the above-mentioned direction and the width in the direction orthogonal to the longitudinal direction is narrower than the length in the longitudinal direction (A2). For example, (see FIG. 3), the extracted second region (A2) is calculated by performing the same procedure as described in the calculation of the surface waviness (Wa1) of the first region (A1) described above. be able to.
Next, the position for extracting the second region (A2) from the above-mentioned interference fringe image in the field of 700 μm × 700 μm is extracted by shifting it from the previous extraction position in the lateral direction of the polyimide film to be measured. Then, for the extracted interference fringe image of the second region (A2), the same procedure as above is repeated to calculate the surface waviness (Wa2) of the second region (A2).
The above-mentioned step of calculating the surface waviness (Wa2) of the second region (A2) was repeated a plurality of times while shifting the extraction position of the second region (A2), and the second region (A2) obtained in each was repeated. By calculating the average value of the surface undulation (Wa2), the average value (Wa2 _ave ) of the surface undulation (Wa2) of the second region (A2) is obtained.

The polyimide film of the laminate of the present invention contains at least polyimide, and may further contain additives and other resins other than polyimide, if necessary, as long as the effects of the present invention are not impaired.

(1) Polyimide Polyimide is obtained by reacting a tetracarboxylic acid component with a diamine component. It is preferable to obtain polyamic acid by polymerization of a tetracarboxylic acid component and a diamine component and imidize it. The imidization may be performed by thermal imidization or chemical imidization. It can also be produced by a method in which thermal imidization and chemical imidization are used in combination.

As a specific example of the tetracarboxylic acid component, tetracarboxylic acid dianhydride is preferably used, and cyclohexanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, dicyclohexane-3, 4, 3', 4 '-Tetracarboxylic acid dianhydride, pyromellitic acid dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride , 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride, 2,2-bis (3,4-dicarboxy) Phenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ) Sulfonhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) Methan dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) Carboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 1,3-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 1,4-bis [ (3,4-dicarboxy) benzoyl] benzene dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, 2,2-bis {4 -[3- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [ 3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, 4,4'-bis [4- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, 4,4'-bis [ 3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [3- (1) , 2-Dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfonate dianhydride, bis {4- [3- (1,2) -Dicarboxy) phenoxy] phenyl} su Luhon dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride Anhydride, 4,4'-(hexafluoroisopropylidene) diphthalic acid anhydride, 3,4'-(hexafluoroisopropyridene) diphthalic acid anhydride, 3,3'-(hexafluoroisopropyridene) diphthalic acid anhydride , 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 1, , 2,3,4-benzenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1, Examples thereof include 2,7,8-phenanthrentetracarboxylic acid dianhydride.
These can be used alone or in combination of two or more.

Specific examples of the diamine component include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3. '-Diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone , 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzanilide, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-Diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) ) Benzene, 2,2-di (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3 , 3,3-Hexafluoropropane, 2- (3-aminophenyl) -2- (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-di (3) -Aminophenyl) -1-phenylethane, 1,1-di (4-aminophenyl) -1-phenylethane, 1- (3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) Benzene, 1,3-bis (3-aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, 1,4-bis (3-aminobenzoyl) benzene, 1,4-bis (4-amino) Benzoyl) benzene, 1,3-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-) Amino-α, α-dimethylbenzyl) benzene, 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene , 1,3-bis (4) -Amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (4-amino-α, α-ditri) Fluoromethylbenzyl) benzene, 2,6-bis (3-aminophenoxy) benzonitrile, 2,6-bis (3-aminophenoxy) pyridine, N, N'-bis (4-aminophenyl) terephthalamide, 9, 9-Bis (4-aminophenyl) fluorene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 3,3'-dichloro- 4,4'-Diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-bis (3-aminophenoxy) Biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3) -Aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide,

Bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-amino) Phenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-Aminophenoxy) Benzene] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3 3,3-Hexafluoropropane, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,4-bis [ 4- (3-Aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) -α, α-dimethyl Benzene] Benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] Benzene, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 4,4'-bis [4- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'- Bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, 4,4' -Bis [4- (4-aminophenoxy) phenoxy] diphenylsulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3, 3'-Diamino-4-phenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 6,6'-bis (3-aminophenoxy) -3,3,3', 3'-tetramethyl-1 , 1'-spirobiindan, 6,6'-bis (4-aminophenoxy) -3,3,3', 3'-tetramethyl-1,1'-spirobiindan, 1,3-bis (3-aminopropyl) Tetramethyldisiloxane, 1,3-bis (4-aminobutyl) tetramethyldisiloxane, α, ω -Bis (3-aminopropyl) polydimethylsiloxane, α, ω-bis (3-aminobutyl) polydimethylsiloxane, bis (aminomethyl) ether, bis (2-aminoethyl) ether, bis (3-aminopropyl) Ether, bis (2-aminomethoxy) ethyl] ether, bis [2- (2-aminoethoxy) ethyl] ether, bis [2- (3-aminoprotoxy) ethyl] ether,

trans-cyclohexanediamine, trans-1,4-bismethylenecyclohexanediamine, 2,6-bis (aminomethyl) bicyclo [2,2,1] heptane, 2,5-bis (aminomethyl) bicyclo [2,2] 1] Heptane, or a diamine in which a part or all of the hydrogen atom on the aromatic ring of the above amine is substituted with a substituent selected from a fluoro group, a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group. Can also be used.
It should be noted that these diamines can be used alone or in combination of two or more.

Above all, from the viewpoint of improving the light transmittance and the impact resistance of the produced polyimide film, it contains an aromatic ring, and (i) a fluorine atom, (ii) an aliphatic ring, and (iii). ) It is preferable to contain a polyimide containing at least one selected from the group consisting of a structure in which aromatic rings are linked to each other by a sulfonyl group or an alkylene group which may be substituted with a fluorine atom. Since the polyimide contains an aromatic ring, the orientation is increased and the rigidity is improved, so that the impact resistance is improved, but the transmittance tends to decrease depending on the absorption wavelength of the aromatic ring.
When (i) a fluorine atom is contained in the polyimide, it is possible to make it difficult for the electronic state in the polyimide skeleton to transfer charge, and thus the light transmittance of the polyimide film is improved.
When the (ii) aliphatic ring is contained in the polyimide, the light transmittance of the polyimide film is improved in that the transfer of charges in the skeleton can be inhibited by breaking the conjugation of π electrons in the polyimide skeleton.
When the polyimide contains a structure in which (iii) aromatic rings are linked to each other with an alkylene group which may be substituted with a sulfonyl group or a fluorine atom, the transfer of charge in the skeleton by breaking the conjugation of π electrons in the polyimide skeleton. The light transmittance of the polyimide film is improved from the point that it can inhibit the above.

Among them, a polyimide containing an aromatic ring and containing a fluorine atom is preferably used from the viewpoint of improving the light transmission property and the impact resistance of the produced polyimide film.
As for the content ratio of fluorine atoms, the ratio (F / C) of the number of fluorine atoms (F) to the number of carbon atoms (C) measured on the polyimide surface by X-ray photoelectron spectroscopy is preferably 0.01 or more. Further, it is preferably 0.05 or more. On the other hand, if the content ratio of fluorine atoms is too high, the heat resistance inherent in polyimide may deteriorate. Therefore, the ratio (F / C) of the number of fluorine atoms (F) to the number of carbon atoms (C) is 1 or less. It is preferably 0.8 or less, and more preferably 0.8 or less.
Here, the ratio of each atom measured by X-ray photoelectron spectroscopy (XPS) is determined from the value of the atomic% of each atom measured using an X-ray photoelectron spectrometer (for example, Theta Probe of Thermo Scientific). Can be done.

Further, the polyimide has a tetracarboxylic acid residue having an aromatic ring when the total of the tetracarboxylic acid residue and the diamine residue is 100 mol%, because the impact resistance of the produced polyimide film is improved. The total amount of diamine residues having a group and an aromatic ring is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 75 mol% or more.

Further, in the polyimide, at least one of the tetracarboxylic acid residue and the diamine residue may contain an aromatic ring and a fluorine atom from the viewpoint of improving the impact resistance and light transmission of the produced polyimide film. It is preferable that both the tetracarboxylic acid residue and the diamine residue further contain an aromatic ring and a fluorine atom.
The polyimide has a tetracarboxylic acid residue having an aromatic ring and a fluorine atom and a diamine residue having an aromatic ring and a fluorine atom when the total of the tetracarboxylic acid residue and the diamine residue is 100 mol%. The total is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 75 mol% or more.

Further, the fact that 50% or more of the hydrogen atoms bonded to the carbon atoms contained in the polyimide are polyimides that are hydrogen atoms directly bonded to the aromatic ring improves the light transmittance of the produced polyimide film and also. , It is preferably used from the viewpoint of improving rigidity. The ratio of the hydrogen atoms (number) directly bonded to the aromatic ring to the total hydrogen atoms (number) bonded to the carbon atoms contained in the polyimide is preferably 60% or more, more preferably 70% or more. Is preferable.
When 50% or more of the hydrogen atoms bonded to the carbon atoms contained in the polyimide are the hydrogen atoms directly bonded to the aromatic ring, the polyimide is stretched at, for example, 200 ° C. or higher even after being heated in the atmosphere. However, it is preferable because the optical characteristics of the produced polyimide film, particularly the change in the total light transmittance and the yellowness YI value are small.
When 50% or more of the hydrogen atoms bonded to the carbon atoms contained in the polyimide are the hydrogen atoms directly bonded to the aromatic ring, the reactivity with oxygen is low, so that the chemical structure of the polyimide changes. It is presumed that it is difficult to do.
Utilizing its high heat resistance, polyimide film is often used for devices that require a processing process that involves heating, but 50% or more of the hydrogen atoms bonded to carbon atoms contained in polyimide are in the aromatic ring. In the case of polyimide, which is a hydrogen atom to be directly bonded, it is not necessary to carry out these subsequent steps in an inert atmosphere in order to maintain transparency, so there is an advantage that equipment costs and costs for atmosphere control can be suppressed. There is.
Here, the ratio of the hydrogen atoms (number) directly bonded to the aromatic ring to the total hydrogen atoms (number) bonded to the carbon atoms contained in the polyimide is determined by high-speed liquid chromatography and gas chromatograph mass of the decomposition product of the polyimide. It can be determined using an analyzer and NMR.
For example, the sample is decomposed with an alkaline aqueous solution or supercritical methanol, the obtained decomposition product is separated by high performance liquid chromatography, and the qualitative analysis of each separated peak is performed by a gas chromatograph mass analyzer, NMR, etc. The ratio of hydrogen atoms (number) directly bonded to the aromatic ring can be determined from the total hydrogen atoms (number) contained in the polyimide by performing the procedure using high performance liquid chromatography and quantifying the amount.

Further, from the viewpoint of improving the bending resistance, a polyimide containing a silicon atom can be preferably used.
As the polyimide containing a silicon atom used in the present invention, the diamine residue having a silicon atom is preferably 1 mol% or more and 50 mol% or less, more preferably 2.5 mol%, of the total amount of diamine residues. A polyimide containing 40 mol% or more, more preferably 5 mol% or more and 30 mol% or less, is preferably used.

As the diamine residue having a silicon atom, a diamine residue having one or two silicon atoms in the main chain is preferable.
Examples of the diamine having one silicon atom in the main chain include a diamine represented by the following general formula (A). Examples of the diamine having two silicon atoms in the main chain include diamines represented by the following general formula (B).

（一般式（Ａ）及び一般式（Ｂ）において、Ｌはそれぞれ独立して、直接結合又は－Ｏ－結合であり、Ｒ^１０はそれぞれ独立して、置換基を有していても良く、酸素原子又は窒素原子を含んでいても良い炭素数１以上２０以下の１価の炭化水素基を表す。Ｒ^１１はそれぞれ独立して、置換基を有していても良く、酸素原子又は窒素原子を含んでいても良い炭素数１以上２０以下の２価の炭化水素基を表す。）

(In the general formula (A) and the general formula (B), L may be an independent direct bond or an —O— bond, and R ¹⁰ may be independent and have a substituent, and oxygen may be used. It represents a monovalent hydrocarbon group having 1 or more and 20 or less carbon atoms which may contain an atom or a nitrogen atom. R ¹¹ may independently have a substituent and may contain an oxygen atom or a nitrogen atom. It represents a divalent hydrocarbon group having 1 or more and 20 or less carbon atoms which may be contained.)

Examples of the monovalent hydrocarbon group represented by R ¹⁰ include an alkyl group having 1 to 20 carbon atoms, an aryl group, and a combination thereof. The alkyl group may be linear, branched or cyclic, and may be linear or a combination of branched and cyclic.
The alkyl group having 1 or more and 20 or less carbon atoms is preferably an alkyl group having 1 or more and 10 or less carbon atoms, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. Examples thereof include a t-butyl group, a pentyl group and a hexyl group. The cyclic alkyl group is preferably a cycloalkyl group having 3 to 10 carbon atoms, and specific examples thereof include a cyclopentyl group and a cyclohexyl group. The aryl group is preferably an aryl group having 6 to 12 carbon atoms, and specific examples thereof include a phenyl group, a tolyl group, and a naphthyl group. Further, the monovalent hydrocarbon group represented by R10 may be an aralkyl group, and examples thereof include a benzyl group, a phenylethyl group and a phenylpropyl group.
Examples of the hydrocarbon group that may contain an oxygen atom or a nitrogen atom include an ether bond, a carbonyl bond, an ester bond, an amide bond, and an imino of a divalent hydrocarbon group described later and the monovalent hydrogen group. Groups bonded by at least one of the bonds (-NH-) can be mentioned.
The substituent that the monovalent hydrocarbon group represented by ^R10 may have is not particularly limited as long as the effect of the present invention is not impaired, and for example, a halogen atom such as a fluorine atom or a chlorine atom. , Hydrocarbons and the like.

The monovalent hydrocarbon group represented by R ¹⁰ is preferably an alkyl group having 1 or more and 3 or less carbon atoms or an aryl group having 6 or more and 10 or less carbon atoms from the viewpoint of impact resistance and bending resistance. .. The alkyl group having 1 or more and 3 or less carbon atoms is more preferably a methyl group, and the aryl group having 6 or more and 10 or less carbon atoms is more preferably a phenyl group.

Examples of the divalent hydrocarbon group represented by R ¹¹ include an alkylene group having 1 to 20 carbon atoms, an arylene group, and a group in combination thereof. The alkylene group may be linear, branched or cyclic, and may be linear or a combination of branched and cyclic.
The alkylene group having 1 or more and 20 or less carbon atoms is preferably an alkylene group having 1 or more and 10 or less carbon atoms. Examples thereof include a group obtained by combining a cyclic or branched alkylene group with a cyclic alkylene group.
The arylene group is preferably an arylene group having 6 to 12 carbon atoms, and examples of the arylene group include a phenylene group, a biphenylene group, a naphthylene group and the like, and further have a substituent for an aromatic ring described later. You may be.
Divalent hydrocarbon groups that may contain an oxygen atom or a nitrogen atom include ether bonds, carbonyl bonds, ester bonds, amide bonds, and imino bonds (-NH-) of the divalent hydrocarbon groups. Examples include at least one bonded group.
The substituent that the divalent hydrocarbon group represented by R11 may have is the same as the substituent that the monovalent hydrocarbon group represented by ^R10 may have. good.

The divalent hydrocarbon group represented by R ¹¹ is preferably an alkylene group having 1 or more and 6 or less carbon atoms or an arylene group having 6 or more and 10 or less carbon atoms from the viewpoint of impact resistance and bending resistance. Further, it is more preferably an alkylene group having 2 or more and 4 or less carbon atoms.

As the diamine having one or two silicon atoms in the main chain, the diamine having two silicon atoms is preferable from the viewpoint of light transmission, impact resistance and bending resistance, and further 1, 3 -Bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-aminobutyl) tetramethyldisiloxane, 1,3-bis (5-aminopentyl) tetramethyldisiloxane, etc. are easily available. It is preferable from the viewpoint of achieving both light transmission and impact resistance.

From the viewpoint of impact resistance and bending resistance, the molecular weight of the diamine residue having one or two silicon atoms in the main chain is preferably 1000 or less, more preferably 800 or less, and more preferably 500 or less. It is even more preferable, and it is particularly preferable that it is 300 or less.
The diamine residue having one or two silicon atoms in the main chain may be used alone or in combination of two or more.

Examples of the polyimide contained in the polyimide film include a polyimide having a structure represented by the following general formula (1).

（一般式（１）において、Ｒ^１はテトラカルボン酸残基である４価の基を表し、Ｒ^２はジアミン残基である２価の基を表す。ｎは繰り返し単位数を表す。）

(In the general formula (1), R ¹ represents a tetravalent group which is a tetracarboxylic acid residue, R ² represents a divalent group which is a diamine residue, and n represents the number of repeating units.)

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

Examples of R ¹ in the general formula (1) include residues obtained by removing four carboxyl groups or an acid dianhydride structure from the above-mentioned tetracarboxylic acid component, and as R ² in the general formula (1). For example, a residue obtained by removing two amino groups from the above-mentioned diamine component can be mentioned.

Further, as the R ² of the general formula (1), for example, a divalent group represented by the following general formula (2) can be mentioned.

（一般式（２）において、Ｒ^ａ及びＲ^ｂはそれぞれ独立に、水素原子、アルキル基、又はパーフルオロアルキル基を表す。）

(In the general formula (2), Ra and R ^b independently represent ^a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

In the structure represented by the general formula (1), n represents the number of repeating units and is 1 or more. The number of repeating units n in the polyimide can be appropriately selected depending on the structure so that the polyimide film shows a preferable glass transition temperature described later, and is not particularly limited.
The average number of repeating units is usually 10 to 2000, and more preferably 15 to 1000.

Further, in the polyimide, the structure represented by the general formula (1) is preferably 95% or more, more preferably 98% or more, and 100% of the total number of repeating units of the polyimide. Is even more preferable.
The polyimide may have a structure different from the structure represented by the general formula (1) in a part thereof as long as the effect of the present invention is not impaired. Examples of the structure different from the structure represented by the general formula (1) include a polyamide structure. Examples of the polyamide structure that may be contained include a polyamide-imide structure containing a tricarboxylic acid residue such as trimellitic acid anhydride and a polyamide structure containing a dicarboxylic acid residue such as terephthalic acid.

The polyimide film preferably has a polyimide content of 50% by mass or more, more preferably 60% by mass or more, based on the total amount of the polyimide film. The upper limit of the content of the polyimide may be appropriately adjusted depending on the contained components.

From the viewpoint of heat resistance, the polyimide contained in the polyimide film preferably has a glass transition temperature of 250 ° C. or higher, more preferably 270 ° C. or higher. On the other hand, from the viewpoint of reducing the baking temperature, the glass transition temperature is preferably 400 ° C. or lower.
For the glass transition temperature of polyimide, use a dynamic viscoelastic modulus measuring device RSA-G2 (TA Instruments Japan Co., Ltd.), set the measuring range to -150 ° C or higher and 490 ° C or lower, and use tension as a deformation mode. Select, perform dynamic viscoelastic measurement with a frequency of 1 Hz, a temperature rise rate of 5 ° C / min, a sample width of 5 mm, and a chuck-to-chuck distance of 20 mm. Obtain the curve of E')) and obtain the temperature of the peak peak. The measurement conditions of the dynamic viscoelasticity measuring device are set as follows. When there are a plurality of peaks on the tanδ curve, the temperature at the apex of the peak having the maximum peak value is defined as the glass transition temperature. When analyzing peaks and inflections, the data is quantified and analyzed from the numerical values without visual evaluation.
<Measurement conditions for RSA-G2>
(Initial value)
Axial force: 3.0 g
Sensitivity: 1.0 g
Proportional force Mode: Force Tracking
Axial Force> Dynamic Force: 1.5%
Minimum axial force: 2.0 g
Projected Extension Below: 0 Pa
(Auto stream)
Mode: Embedded
Strine adjust: 20.0%
Minimum strine: 0.01%
Maximum stripe: 3.0%
Minimum force: 1.5 g
Maximum force: 200.0 g
(Test parameters)
Sampling rate: 10pts / s
Straight%: 0.1%
Frequency: Single point
Frequency 1Hz
As a sample for measuring the tan δ curve, a polyimide film that was left to stand in an environment of 23 ° C ± 2 ° C RH 30 to 50% for 24 hours was sampled to a size of 10 cm square or more, and the central part of the film was sampled with a razor or a scalpel. Using a cutting jig with a slit in a width of 5 mm, a material cut into a width of 5 mm × a length of 50 mm (so that the sample length becomes 20 mm at the time of chucking) is used. The width is measured using a caliper, and the average value measured three times at different positions is recorded. At this time, if a part of the width measurement has a fluctuation range of 3% or more of the average value, the sample is not used.

(2) Additives The polyimide film may further contain additives, if necessary, in addition to the polyimide. Examples of the additive include a silica filler for facilitating winding, a surfactant for improving film forming property and defoaming property, and the like.

Further, the polyimide film may contain a resin other than polyimide as long as the effect of the present invention is not impaired. Examples of the other resin include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyimide resins, polyamide resins, polyamideimide resins, polyphenylene sulfide resins, polyether ether ketone resins, and polyether sulfone resins. , Polycarbonate resin, polyetherimide resin, epoxy resin, phenol resin, glass-epoxy resin, polyphenylene ether resin, acrylic resin, polyolefin resin such as polyethylene and polypropylene, polycycloolefin such as polynorbornene and the like.
When the polyimide film contains a resin other than polyimide, the content of the other resin is preferably 50% by mass or less, more preferably 30% by mass or less, based on the total amount of the polyimide layer. It is preferably 0% by mass, and particularly preferably 0% by mass.

(3) Characteristics of Polyimide Film The polyimide film contained in the laminate of the present invention preferably has a total light transmittance of 90% or more, and further preferably 91% or more, as measured in accordance with JIS K7361-1. preferable. Since the transmittance is high as described above, the transparency is improved and the material can be used as a substitute for glass.
The polyimide film contained in the laminate of the present invention preferably has a total light transmittance of 90% or more, more preferably 91% or more, as measured in accordance with JIS K7361-1 when the thickness is 5 μm or more and 100 μm or less. Is preferable.
Further, the polyimide film of the laminate of the present invention preferably has a total light transmittance of 90% or more, and further 91% or more, as measured in accordance with JIS K7631-1 at a thickness of 50 μm ± 5 μm. It is preferable to have.
The total light transmittance measured according to JIS K7361-1 can be measured by, for example, a haze meter (for example, HM150 manufactured by Murakami Color Technology Laboratory). From the measured value of the total light transmittance of a certain thickness, the converted value of the total light transmittance of different thickness can be obtained by Lambertbert's law, and it can be used.

Specifically, according to Lambert-Beer's law, the transmittance T is
Log10 (1 / T) = kcb
It is represented by (k = substance-specific constant, c = concentration, b = optical path length).
In the case of film transmittance, c is also a constant assuming that the density is constant even if the film thickness changes. Therefore, in the above equation, Log10 (1 / T) = fb using the constant f.
It can be expressed as (f = kc). Here, if the transmittance at a certain film thickness is known, the unique constant f of each substance can be obtained. Therefore, by substituting the constant unique to f and the target film thickness into b using the equation of T = 1/10 f · b, the transmittance at the desired film thickness can be obtained.

Further, the polyimide film contained in the laminate of the present invention preferably has a haze value based on JIS K-7105 of 2.0 or less, more preferably 1.2 or less, from the viewpoint of light transmission. It is more preferably 1.0 or less, and even more preferably 0.5 or less. Such a low haze value improves light transmission and can be a substitute for glass.
It is preferable that the haze value can be achieved when the thickness of the polyimide film is 5 μm or more and 100 μm or less.
Further, the polyimide film of the laminate of the present invention preferably has a haze value of 2.0 or less, more preferably 1.2 or less, in accordance with JIS K-7105 at a thickness of 50 μm ± 5 μm. , 1.0 or less, and even more preferably 0.5 or less.
The haze value can be measured by a method according to JIS K-7105, and can be measured by, for example, a haze meter HM150 manufactured by Murakami Color Technology Laboratory.
From the measured value of the haze value of a certain thickness, the haze value of a different thickness is determined by the haze value at each wavelength measured at 5 nm intervals between 380 nm and 780 nm of a sample of a specific film thickness and the above method. The diffusion transmittance of each wavelength is calculated from the total light transmittance of each measured wavelength, and the converted value of the diffusion transmittance at each wavelength having a different thickness is obtained according to Lambert-Bale's law as in the case of the total light transmittance. The haze value can be calculated and used as the ratio of the diffuse transmittance to the total light transmittance.

Further, the polyimide film of the laminate of the present invention preferably has a yellowness (YI value) of 5.0 or less, preferably 3.0 or less, calculated in accordance with JIS K7373-2006. More preferably, it is more preferably 2.0 or less.
Since the polyimide film of the laminate of the present invention has such a low yellowness, yellowish coloring is suppressed, light transmission is improved, and it can be used as a glass substitute material.
The polyimide film of the laminate of the present invention preferably has a yellowness (YI value) of 5.0 or less, preferably 3.0 or less, when the thickness is 5 μm or more and 100 μm or less, and the yellowness (YI value) calculated in accordance with the JIS K7373-2006 is 5.0 or less. It is more preferably 0 or less, and further preferably 2.0 or less.
Further, the polyimide film of the laminate of the present invention preferably has a thickness of 50 μm ± 5 μm and a yellowness (YI value) of 5.0 or less calculated in accordance with the JIS K7373-2006. It is more preferably 0.0 or less, and further preferably 2.0 or less.
The yellowness (YI value) is based on JIS K7373-2006, using an ultraviolet-visible near-infrared spectrophotometer (Nippon Spectroscopy Co., Ltd. V-7100), and by a spectrophotometric method, auxiliary illumination C. Tristimulus values X, Y, Z in the XYZ colorimetric system were obtained based on the transmittance measured at 1 nm intervals in the range of 250 nm or more and 800 nm or less using a two-degree visual field, and the values of X, Y, Z were obtained. It can be calculated from the following formula.
YI = 100 (1.2769X-1.592Z) / Y
From the measured value of the yellowness of a certain thickness, the yellowness of a different thickness is the above-mentioned total for each transmittance at each wavelength measured at 5 nm intervals between 380 nm and 780 nm of a sample of a specific film thickness. Similar to the light transmittance, the converted value of each transmittance at each wavelength having a different thickness can be obtained by Lambertvale's law, and can be calculated and used based on the converted value.

A preferable form of the polyimide film possessed by the laminate of the present invention is the ratio (F / C) of the number of fluorine atoms (F) to the number of carbon atoms (C) on the film surface measured by X-ray photoelectron spectroscopy of the polyimide film. ) Is preferably 0.01 or more and 1 or less, and more preferably 0.05 or more and 0.8 or less.
Further, the ratio (F / N) of the number of fluorine atoms (F) to the number of nitrogen atoms (N) on the film surface measured by the X-ray photoelectron spectroscopy of the polyimide film of the laminate of the present invention is 0.1 or more. It is preferably 20 or less, and more preferably 0.5 or more and 15 or less.
Further, the ratio (F / Si) of the number of fluorine atoms (F) to the number of silicon atoms (Si) on the film surface measured by X-ray photoelectron spectroscopy of the polyimide film of the laminate of the present invention is 1 or more and 50 or less. It is preferable that the amount is 3 or more and 30 or less.
Here, the above ratio measured by X-ray photoelectron spectroscopy (XPS) is determined from the value of the atomic% of each atom of the polyimide film measured using an X-ray photoelectron spectrometer (for example, Theta Probe of Thermo Scientific). be able to.

Further, the atomic% of the silicon atom (Si) on the surface of the film measured by X-ray photoelectron spectroscopy of the polyimide film of the laminate of the present invention is preferably 0.1 or more and 10 or less, and more preferably 0.2 or more and 5 or less. preferable.
In the present invention, each atomic concentration of the polyimide film measured by X-ray photoelectron spectroscopy (XPS) can be measured using an X-ray photoelectron spectroscope (for example, Thetera Probe of Thermo Scientific).

Further, the glass transition temperature of the polyimide film of the laminate of the present invention is preferably 150 ° C. or higher, and more preferably 200 ° C. or higher, from the viewpoint of heat resistance. On the other hand, from the viewpoint of reducing the baking temperature, it is preferably 400 ° C. or lower, and more preferably 380 ° C. or lower. Further, the polyimide film of the laminate of the present invention preferably has one glass transition temperature in a temperature range of 150 ° C. or higher and 400 ° C. or lower.
For the glass transition temperature, a dynamic viscoelastic modulus measuring device RSA-G2 (TA Instruments Japan Co., Ltd.) was used, the measuring range was set to -150 ° C or higher and 490 ° C or lower, and tension was applied as a deformation mode. The dynamic viscoelastic modulus was measured with a frequency of 1 Hz, a temperature rise rate of 5 ° C./min, a sample width of 5 mm, and a chuck-to-chuck distance of 20 mm. Obtain the curve of (E')) and obtain the temperature of the peak peak. The measurement conditions of the dynamic viscoelasticity measuring device are set as follows. When there are a plurality of peaks on the tanδ curve, the temperature at the apex of the peak having the maximum peak value is defined as the glass transition temperature. When analyzing peaks and inflections, the data is quantified and analyzed from the numerical values without visual evaluation.
<Measurement conditions for RSA-G2>
(Initial value)
Axial force: 3.0 g
Sensitivity: 1.0 g
Proportional force Mode: Force Tracking
Axial Force> Dynamic Force: 1.5%
Minimum axial force: 2.0 g
Projected Extension Below: 0 Pa
(Auto stream)
Mode: Embedded
Strine adjust: 20.0%
Minimum strine: 0.01%
Maximum stripe: 3.0%
Minimum force: 1.5 g
Maximum force: 200.0 g
(Test parameters)
Sampling rate: 10pts / s
Straight%: 0.1%
Frequency: Single point
Frequency 1Hz
As a sample for measuring the tan δ curve, a polyimide film that was left to stand in an environment of 23 ° C ± 2 ° C RH 30 to 50% for 24 hours was sampled to a size of 10 cm square or more, and the central part of the film was sampled with a razor or a scalpel. Using a cutting jig with a slit in a width of 5 mm, a material cut into a width of 5 mm × a length of 50 mm (so that the sample length becomes 20 mm at the time of chucking) is used. The width is measured using a caliper, and the average value measured three times at different positions is recorded. At this time, if a part of the width measurement has a fluctuation range of 3% or more of the average value, the sample is not used.

Further, the polyimide film possessed by the laminate of the present invention has a tensile elastic modulus at 25 ° C., which is measured by measuring a 15 mm × 40 mm test piece in accordance with JIS K7127-1989 with a tensile speed of 10 mm / min and a chuck distance of 20 mm. It is preferably 1.8 GPa or more. Since the high tensile elastic modulus provides sufficient surface hardness as a protective film, the polyimide film of the laminate of the present invention can be suitably used as a surface material. The tensile elastic modulus is preferably 2.0 GPa or more, and more preferably 2.4 GPa or more.
The tensile elastic modulus was determined by cutting a test piece having a width of 15 mm and a length of 40 mm from a polyimide film using a tensile tester (for example, manufactured by Shimadzu Corporation: Autograph AG-X 1N, load cell: SBL-1KN) and at 25 ° C. The tensile speed is 10 mm / min, and the distance between chucks is 20 mm. The thickness of the polyimide film used to determine the tensile elastic modulus is preferably 50 μm ± 5 μm.

Further, in the polyimide film possessed by the laminate of the present invention, the internal angle measured in the test is 120 ° or more when the static bending test is performed according to the following static bending test method because of its excellent bending resistance. It is preferably 125 ° or more, more preferably 130 ° or more, and even more preferably 130 ° or more.
[Static bending test method]
A polyimide film test piece cut into a size of 15 mm × 40 mm is bent at the position of half of the long side, and a metal piece (100 mm × 30 mm × 6 mm) having a thickness of 6 mm is sandwiched between both ends of the long side of the test piece from the upper and lower surfaces. Arranged and fixed with tape so that the overlap margins on both ends of the test piece and the upper and lower surfaces of the metal piece are 10 mm each, sandwiched between glass plates (100 mm x 100 mm x 0.7 mm) from above and below. , The test piece is fixed in a bent state with an inner diameter of 6 mm. At that time, a dummy test piece is sandwiched between the metal piece and the glass plate where the test piece does not exist, and the glass plate is fixed with tape so as to be parallel to each other. The test piece fixed in the bent state in this way was allowed to stand for 24 hours in an environment of 60 ± 2 ° C. and 93 ± 2% relative humidity (RH), and then the glass plate and the fixing tape were removed. Release the force applied to the test piece. Then, one end of the test piece is fixed, and the internal angle of the test piece is measured 30 minutes after the force applied to the test piece is released.

Further, the polyimide film of the laminate of the present invention has excellent hygroscopicity and bending resistance under high humidity. Therefore, when the dynamic bending test is performed according to the following dynamic bending test method, the polyimide film has excellent bending resistance. The internal angle of the test piece is preferably 155 ° or more, and more preferably 160 ° or more.
[Dynamic bending test method]
The test piece of the polyimide film cut out to a size of 20 mm × 100 mm is fixed to the endurance test system in a constant temperature and humidity chamber (manufactured by Yuasa System Equipment, planar body no-load U-shaped expansion and contraction test jig DMX-FS) with tape. .. The test piece was set so that the distance between both ends of the long side of the test piece in a bent state similar to the static bending test, that is, the bent state was 6 mm (fixed in a bent state with an inner diameter of 6 mm). Then, in an environment of 60 ± 2 ° C. and 93 ± 2% relative humidity (RH), bending is repeated 200,000 times at 90 times per minute.
Then, the test piece is removed, one end of the obtained test piece is fixed, and the internal angle of the test piece is measured 30 minutes after repeating bending 200,000 times.

Further, in the polyimide film of the laminate of the present invention, when the adhesion test is performed according to the following adhesion test method, the coating film does not peel off, which is a kind of the polyimide film and the functional layer. It is preferable from the viewpoint of adhesion to the coat layer and the surface hardness of the laminated body in which the hard coat layer, which is a functional layer, is laminated adjacent to the polyimide film.
[Adhesion test method]
A composition for adhesion evaluation prepared by adding 10 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone to 100 parts by mass of pentaerythritol triacrylate to a 40% by mass methyl isobutyl ketone solution of pentaerythritol triacrylate. A cured film having a thickness of 10 μm is formed by applying it on a test piece of a polyimide film cut into a size of 10 cm × 10 cm and irradiating it with ultraviolet rays at an exposure amount of 200 mJ / cm ² under a nitrogen stream to cure it. A cross-cut test based on JIS K 5600-5-6 is performed on the cured film, and after repeating the peeling operation with tape 5 times, the presence or absence of peeling of the coating film is observed.

In the polyimide film of the laminate of the present invention, the pencil hardness is preferably 2B or more, more preferably B or more, and even more preferably HB or more.
The pencil hardness of the polyimide film is determined by adjusting the humidity of the measurement sample for 2 hours under the conditions of a temperature of 25 ° C. and a relative humidity of 60%, and then using a test pencil specified by JIS-S-6006, JIS K5600-5-4. It can be performed by performing a pencil hardness test (0.98 N load) specified in (1999) on the film surface and evaluating the highest pencil hardness that does not damage the film. For example, a pencil scratch coating film hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

Further, the polyimide film of the laminate of the present invention preferably has a birefringence of 0.020 or less in the thickness direction at the wavelength of 590 nm.
Since the optical distortion is reduced due to the small birefringence, it is possible to suppress the deterioration of the display quality of the display when the polyimide film is used as the surface material for the display. The birefringence index in the thickness direction at a wavelength of 590 nm is preferably smaller, preferably 0.015 or less, more preferably 0.010 or less, and even more preferably less than 0.008. ..
The birefringence in the thickness direction of the polyimide film of the laminate of the present invention at a wavelength of 590 nm can be determined as follows.
First, the thickness direction retardation value (Rth) of the polyimide film is measured with light at 25 ° C. and a wavelength of 590 nm using a phase difference measuring device (for example, manufactured by Oji Measuring Instruments Co., Ltd., product name “KOBRA-WR”). do.
For the thickness direction retardation value (Rth), the phase difference value incident at 0 degree and the phase difference value incident at an angle of 40 degrees are measured, and the thickness direction retardation value Rth is calculated from these phase difference values. The retardation value of the oblique 40-degree incident is measured by injecting light having a wavelength of 590 nm onto the retardation film from a direction inclined by 40 degrees from the normal of the retardation film.
The birefringence in the thickness direction of the polyimide film can be obtained by substituting it into the formula: Rth / d. The d represents the film thickness (nm) of the polyimide film.
The thickness direction retardation value is nx for the refractive index in the slow-phase axial direction (the direction in which the refractive index is maximized in the in-plane direction of the film) in the in-plane direction of the film, and the phase-advancing axial direction (the film surface) in the film surface. When the refractive index in the inward direction (the direction in which the refractive index is minimized) is ny and the refractive index in the thickness direction of the film is nz, it is expressed as Rth [nm] = {(nx + ny) /2-nz} × d. be able to.

The thickness of the polyimide film of the laminate of the present invention may be appropriately selected depending on the intended use, but is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more. .. On the other hand, it is preferably 200 μm or less, more preferably 150 μm or less, and further preferably 100 μm or less.
If the thickness is thin, the strength is lowered and the film is easily broken, and if the thickness is thick, the difference between the inner diameter and the outer diameter at the time of bending becomes large, and the load on the film becomes large, so that the bending resistance may decrease.

The polyimide film of the laminate of the present invention may be subjected to surface treatment such as saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet treatment, and flame treatment.

3. 3. Functional layer The functional layer of the laminate of the present invention is a layer that is laminated in contact with the first surface of the polyimide film described above.
Examples of the functional layer include a hard coat layer laminated for improving the surface hardness of the polyimide film.

As the hard coat layer, for example, a layer containing at least one polymer of a radically polymerizable compound and a cationically polymerizable compound can be used.

(1) Radical polymerizable compound The radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group contained in the radically polymerizable compound may be any functional group capable of causing a radical polymerization reaction, and is not particularly limited, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specific examples thereof include a vinyl group and a (meth) acryloyl group. When the radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different from each other.

The number of radically polymerizable groups contained in one molecule of the radically polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer.
As the radically polymerizable compound, a compound having a (meth) acryloyl group is preferable from the viewpoint of high reactivity, and a polyfunctional acrylate monomer having 2 to 6 (meth) acryloyl groups in one molecule is used. Preferred compounds have a molecular weight of several hundred to several thousand and have several (meth) acryloyl groups in the molecule called a compound called, urethane (meth) acrylate, polyester (meth) acrylate, or epoxy (meth) acrylate. Can be used.
In addition, in this specification, (meth) acryloyl represents each of acryloyl and methacryloyl, and (meth) acrylate represents each of acrylate and methacrylate.

Specific examples of the radically polymerizable compound include vinyl compounds such as divinylbenzene; ethylene glycol di (meth) acrylate, bisphenol A epoxy di (meth) acrylate, and 9,9-bis [4- (2-(2-(. Meta) acryloyloxyethoxy) phenyl] fluorene, alkylene oxide-modified bisphenol A di (meth) acrylate (for example, ethoxylated (ethylene oxide modified) bisphenol A di (meth) acrylate), trimethyl propantri (meth) acrylate, tri Methylol ethanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Polyacrylate polyacrylates such as dipentaerythritol hexa (meth) acrylates, diacrylates such as bisphenol A diglycidyl ether diacrylates, epoxy acrylates such as hexanediol diglycidyl ether diacrylates, hydroxyl groups such as polyisocinates and hydroxyethyl acrylates. Examples thereof include urethane acrylate obtained by the reaction of the contained acrylate.

(2) Cationicly polymerizable compound The cationically polymerizable compound is a compound having a cationically polymerizable group. The cationically polymerizable group contained in the cationically polymerizable compound may be any functional group capable of causing a cationic polymerization reaction, and is not particularly limited, and examples thereof include an epoxy group, an oxetanyl group, and a vinyl ether group. When the cationically polymerizable compound has two or more cationically polymerizable groups, the cationically polymerizable groups may be the same or different from each other.

The number of cationically polymerizable groups contained in one molecule of the cationically polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hardcoat layer.
Further, as the cationically polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as the cationically polymerizable group is preferable. A cyclic ether group such as an epoxy group or an oxetanyl group is preferable because the shrinkage associated with the polymerization reaction is small. Further, among the cyclic ether groups, compounds having an epoxy group are easily available, compounds having various structures are easily available, the durability of the obtained hard coat layer is not adversely affected, and compatibility with radically polymerizable compounds is easily controlled. There is an advantage. Of the cyclic ether groups, the oxetanyl group has a higher degree of polymerization than the epoxy group and has low toxicity, and when the obtained hard coat layer is combined with a compound having an epoxy group, the cation in the coating film There are advantages such as increasing the network formation rate obtained from the polymerizable compound and forming an independent network without leaving unreacted monomers in the film even in a region mixed with the radically polymerizable compound.

Examples of the cationically polymerizable compound having an epoxy group include polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or a cyclohexene ring or cyclopentene ring-containing compound with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Alicyclic epoxy resin obtained by epoxidation; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long chain polybasic acid, homopolymer of glycidyl (meth) acrylate, An aliphatic epoxy resin such as a copolymer; a glycidyl ether produced by reacting bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or derivatives such as alkylene oxide adducts and caprolactone adducts thereof with epichlorohydrin. And novolak epoxy resin and the like, and examples thereof include glycidyl ether type epoxy resin derived from bisphenols.

Examples of the alicyclic epoxy resin include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (UVR-6105, UVR-6107, UVR-6110) and bis-3,4-epoxycyclohexylmethyl adipate. (UVR-6128) (The above is the trade name in parentheses and is manufactured by Dow Chemical Co., Ltd.).

Examples of the glycidyl ether type epoxy resin include sorbitol polyglycidyl ether (Denacol EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-614B, Denacol EX-622) and polyglycerol polyglycidyl ether (Denacol EX). -512, Denacol EX-521), Pentaeryth Little Polyglycidyl Ether (Denacol EX-411), Diglycerol Polyglycidyl Ether (Denacol EX-421), Gglycerol Polyglycidyl Ether (Denacol EX-313, Denacol EX-314), Trimethylol Propanepolyglycidyl Ether (Denacol EX-321), Resoltinol Diglycidyl Ether (Denacol EX-201), Neopentyl Glycol Diglycidyl Ether (Denacol EX-211), 1,6 Hexanodiol Diglycidyl Ether (Denacol EX-) 212), Hydrodibisphenol A Diglycidyl Ether (Denacol EX-252), Ethylene Glycol Diglycidyl Ether (Denacol EX-810, Denacol EX-811), Polyethylene Glycol Diglycidyl Ether (Denacol EX-850, Denacol EX-851, Denacol EX-821),
Propropylene glycol glycidyl ether (Denacol EX-911), Polypropylene glycol glycidyl ether (Denacol EX-941, Denacol EX-920), Allyl glycidyl ether (Denacol EX-111), 2-Ethylhexyl glycidyl ether (Denacol EX-121), phenyl Glycyzyl ether (Denacol EX-141), Phenol glycidyl ether (Denacol EX-145), Butylphenyl glycidyl ether (Denacol EX-146), Diglycidyl phthalate (Denacol EX-721), Hydroquinone diglycidyl ether (Denacol EX-203) , Diglycidyl terephthalate (Denacol EX-711), Glycidyl phthalimide (Denacol EX-731), Dibromophenyl glycidyl ether (Denacol EX-147), Dibromoneopentyl glycol diglycidyl ether (Denacol EX-221) The product name is made by Nagase Chemtex.).

Other commercially available epoxy resins include Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 828EL, Epicoat 828XA, Epicoat 834, Epicoat 801 and Epicoat 801P, Epicoat 802, Epicoat 815, Epicoat 815XA, and Epicoat 816A. Epicoat 819, Epicoat 834X90, Epicoat 1001B80, Epicoat 1001X70, Epicoat 1001X75, Epicoat 1001T75, Epicoat 806, Epicoat 806P, Epicoat 807, Epicoat 152, Epicoat 154, Epicoat 871, Epicoat 191P, Epicoat YX310, Epicoat DX255, Epicoat YX8000 Etc. (The above product name is made by Japan Epoxy Resin).

Examples of the cationically polymerizable compound having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane (OXT-101) and 1,4-bis-3-ethyloxetane-3-ylmethoxymethylbenzene (OXT-121). , Bis-1-ethyl-3-oxetanylmethyl ether (OXT-221), 3-ethyl-3--2-ethylhexyloxymethyloxetane (OXT-212), 3-ethyl-3-phenoxymethyloxetane (OXT-) 211) (above, the trade name in parentheses is made by Toa Synthetic), and the trade names include Ethanacole EHO, Ethanacole OXBP, Ethanacole OXTP, and Ethanacole OXMA (above, trade name, manufactured by Ube Kosan).

(3) Polymerization Initiator The polymer of at least one of the radically polymerizable compound and the cationically polymerizable compound contained in the hard coat layer of the laminate of the present invention is, for example, the radically polymerizable compound and the cationically polymerizable compound. It can be obtained by adding a polymerization initiator to at least one of the compounds, if necessary, and carrying out a polymerization reaction by a known method.

As the polymerization initiator, a radical polymerization initiator, a cationic polymerization initiator, a radical, a cationic polymerization initiator and the like can be appropriately selected and used. These polymerization initiators are decomposed by at least one of light irradiation and heating to generate radicals or cations to promote radical polymerization and cation polymerization.

The radical polymerization initiator may be any kind as long as it can release a substance that initiates radical polymerization by at least one of light irradiation and heating. For example, examples of the photoradical polymerization initiator include imidazole derivatives, bisimidazole derivatives, N-arylglycine derivatives, organic azido compounds, titanosenes, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, thioxanthone derivatives and the like. And more specifically,
1,3-Di (tert-butyldioxycarbonyl) benzophenone, 3,3', 4,4'-tetrakis (tert-butyldioxycarbonyl) benzophenone, 3-phenyl-5-isooxazolone, 2-mercaptobenzimidazole , Bis (2,4,5-triphenyl) imidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name: Irgacure 651, manufactured by Ciba Japan Co., Ltd.), 1-hydroxy-cyclohexyl -Phenyl-ketone (trade name: IrgaCure 184, manufactured by Ciba Japan Co., Ltd.), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1-one (trade name: Irgacure 369, Ciba) -Japan Co., Ltd.), bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium) (commodity Examples include, but are not limited to, Irugacure 784, manufactured by Ciba Japan Co., Ltd., etc.

In addition to the above, commercially available products can be used, specifically, Irgacure 907, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 500, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870 manufactured by Ciba Japan Co., Ltd. 、イルガキュアＯＸＥ０１、ＤＡＲＯＣＵＲ ＴＰＯ、ＤＡＲＯＣＵＲ１１７３、日本シイベルヘグナー（株）製のＳｐｅｅｄｃｕｒｅＭＢＢ、ＳｐｅｅｄｃｕｒｅＰＢＺ、ＳｐｅｅｄｃｕｒｅＩＴＸ、ＳｐｅｅｄｃｕｒｅＣＴＸ、ＳｐｅｅｄｃｕｒｅＥＤＢ、Ｅｓａｃｕｒｅ ＯＮＥ、Ｅｓａｃｕｒｅ ＫＩＰ１５０、Ｅｓａｃｕｒｅ ＫＴＯ４６、日本化薬（株）製のＫＡＹＡＣＵＲＥ ＤＥＴＸ－Ｓ、ＫＡＹＡＣＵＲＥ ＣＴＸ , KAYACURE BMS, KAYACURE DMBI and the like.

Further, the cationic polymerization initiator may be any material as long as it can release a substance that initiates cationic polymerization by at least one of light irradiation and heating. Examples of the cationic polymerization initiator include sulfonic acid ester, imide sulfonate, dialkyl-4-hydroxysulfonium salt, aryl sulfonic acid-p-nitrobenzyl ester, silanol-aluminum complex, (η6-benzene) (η5-cyclopentadienyl). Examples thereof include iron (II), and more specific examples thereof include, but are not limited to, benzointosilate, 2,5-dinitrobenzyltosylate, and N-tosiphthalateimide.

Examples of the agent used as both the radical polymerization initiator and the cationic polymerization initiator include aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, triazine compounds, iron arene complexes and the like. More specifically, chlorides, bromides, borofluorides, hexafluorosulfonium salts, hexafluorosylides of iodoniums such as diphenyliodonium, ditriliodonium, bis (p-tert-butylphenyl) iodonium, and bis (p-chlorophenyl) iodonium. Iodonium salts such as antimonate salts, sulfonium chlorides such as triphenylsulfonium, 4-tert-butyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, bromides, borofluoride salts, hexafluorophosphate salts, hexafluoroantimonates. Sulfonium salts such as salts, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2- Examples thereof include, but are not limited to, 2,4,6-substituted-1,3,5 triazine compounds such as methyl-4,6-bis (trichloromethyl) -1,3,5-triazine. ..

(4) Additive The hard coat layer of the laminate of the present invention is, if necessary, an antistatic agent, an antiglare agent, an antifouling agent, and an inorganic or organic material for improving hardness, in addition to the polymer. It may contain additives such as fine particles, a leveling agent, and various sensitizers.

The hard coat layer may be provided with functions such as antireflection property and antiglare property. The function can be imparted, for example, by subjecting the hard coat layer to a known surface treatment or by incorporating an additive such as inorganic or organic fine particles.

Further, in the laminated body of the present invention, in addition to the polyimide film and the hard coat layer, other layers such as gel containing urethane, acrylic resin and the like are further added as a functional layer as long as the effect of the present invention is not impaired. It may be laminated.

Further, the functional layer is not limited to the hard coat layer, and may be, for example, an antireflection layer or an antiglare layer, and is a primer layer for improving the adhesion between the polyimide film and the hard coat layer. May be good.
Further, the functional layer may be a single layer or may include a plurality of layers. Further, the functional layer may be a layer having a single function, or may include a layer having different functions from each other.

The overall thickness of the laminate of the present invention may be appropriately selected depending on the intended use, but is preferably 10 μm or more, and more preferably 40 μm or more from the viewpoint of strength. On the other hand, from the viewpoint of bending resistance, it is preferably 300 μm or less, and more preferably 250 μm or less.
Further, in the laminated body of the present invention, the thickness of each functional layer may be appropriately selected depending on the intended use, but is preferably 2 μm or more and 80 μm or less, and more preferably 3 μm or more and 50 μm or less. Further, from the viewpoint of curl prevention, functional layers such as a hard coat layer may be formed on both sides of the polyimide film.

(5) Characteristics of Laminated Body The laminated body of the present invention preferably has a pencil hardness of the surface on the laminated body side of HB or more, more preferably F or more, and even more preferably H or more.
The pencil hardness of the laminate of the present invention can be measured in the same manner as the pencil hardness of the polyimide film.

The laminated body of the present invention preferably has a total light transmittance of 85% or more, more preferably 88% or more, and further more than 90%, as measured in accordance with JIS K7361-1. Is preferable. Since the transmittance is high as described above, the transparency is improved and the material can be used as a substitute for glass.
The total light transmittance of the laminate of the present invention can be measured in the same manner as the total light transmittance measured in accordance with JIS K7361-1 of the polyimide film.

The laminate of the present invention preferably has a yellowness (YI value) calculated in accordance with JIS K7373-2006 of 5.0 or less, more preferably 3.0 or less, and 2.0 or less. The following is even more preferable.
In the laminated body of the present invention, the yellowness (YI value) can be measured in the same manner as the yellowness (YI value) calculated in accordance with JIS K7373-2006 of the polyimide film.

The haze value of the laminate of the present invention according to JIS K-7105 is preferably 5.0 or less, more preferably 2.0 or less, and 1.2 or less from the viewpoint of light transmission. It is more preferably 1.0 or less, still more preferably 0.5 or less.
The haze value of the laminate of the present invention according to JIS K-7105 can be measured in the same manner as the haze value of the polyimide film.

The birefringence in the thickness direction of the laminate of the present invention at a wavelength of 590 nm is preferably 0.020 or less, preferably 0.015 or less, more preferably 0.010 or less, and even more. It is preferably less than 0.008.
The birefringence of the laminate of the present invention can be measured in the same manner as the birefringence in the thickness direction of the polyimide film at a wavelength of 590 nm.

(6) Use of Laminated Body The use of the laminated body of the present invention is not particularly limited, and it can be used as a member such as a base material or a surface material in which a glass product such as a thin plate glass has been conventionally used. Since the laminate of the present invention has improved adhesion, appearance, and optical characteristics between the polyimide film and the functional layer, it can be suitably used as a member such as a base material or a surface material for a display.
Specifically, the laminate of the present invention is used for, for example, a thin and bendable flexible type organic EL display, a mobile terminal such as a smartphone or a wristwatch type terminal, a display device inside an automobile, a flexible panel used for a wristwatch, or the like. It can be suitably used. Further, the laminate of the present invention includes a member for an image display device such as a liquid crystal display device and an organic EL display device, a member for a touch panel, a flexible printed substrate, a member for a solar cell panel such as a surface protective film and a substrate material, and an optical waveguide. It can also be applied to members for materials and other semiconductor-related members.

II. Polyimide film The polyimide film of the present invention has a long shape, and is a polyimide film for forming a functional layer for forming a functional layer on the first surface when one surface is used as the first surface. In the field of 700 μm × 700 μm in the first plane, the polyimide film extends in a direction orthogonal to the longitudinal direction, and the width in the longitudinal direction is larger than the length in the direction orthogonal to the longitudinal direction. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) arbitrarily extracted so as to be narrow, and the polyimide film extending in the longitudinal direction and extending in the longitudinal direction. The difference (Wa1) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) arbitrarily extracted so that the width in the direction orthogonal to is narrower than the length in the longitudinal direction. _ave -Wa2 _ave ) is 20 nm or less, and the surface roughness (Sa) in the field of 71 μm × 95 μm in the first plane is 1 nm or more and 10 nm or less.
Since the specific structure of the polyimide film of the present invention is the same as the structure and characteristics of the polyimide film described in "I. Laminate", detailed description thereof will be omitted.
The polyimide film of the present invention exhibits excellent adhesion to the functional layer, has a good appearance, and has excellent optical characteristics.

The use of the polyimide film of the present invention is not particularly limited, and for example, it can be used in the same manner as the above-mentioned use of the laminate of the present invention.

III. Method for manufacturing a polyimide film In the method for manufacturing a polyimide film of the present invention, the surface of a long support is polished so as to be orthogonal to the longitudinal direction of the support in a 700 μm × 700 μm field of view of the surface of the support. The average of the surface waviness (Wa1) of the first region (B1) arbitrarily extracted so as to extend in the direction in which the surface is formed and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The value (Wa1 _ave ) and the width extending along the longitudinal direction of the support and orthogonal to the longitudinal direction were arbitrarily extracted so as to be narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (B2) is set to 20 nm or less, and in a field of view of 71 μm × 95 μm on the surface of the support. A step of setting the surface roughness (Sa) to 1 nm or more and 10 nm or less, and
A polyimide precursor composition containing a polyimide precursor and an organic solvent is applied to the surface of the support to form a coating film of the polyimide precursor composition, or a polyimide composition containing a polyimide and an organic solvent. To form a coating film of the polyimide composition by applying
The organic solvent is removed from the coating film of the polyimide precursor composition and the polyimide precursor contained in the coating film of the polyimide precursor composition is imidized, or the organic is said from the coating film of the polyimide composition. It comprises a step of forming a polyimide film by removing the solvent.

(First manufacturing method)
The method for producing a polyimide film of the present invention is, for example, as a first production method, in which the surface of a long support is polished so that the surface of the support has a visual field of 700 μm × 700 μm. The surface waviness of the first region (B1) arbitrarily extracted so as to extend in the direction orthogonal to the longitudinal direction and to have the width in the longitudinal direction narrower than the length in the direction orthogonal to the longitudinal direction (B1). The average value (Wa1 _ave ) of Wa1) and the width extending along the longitudinal direction of the support and perpendicular to the longitudinal direction are narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (B2) arbitrarily extracted is 20 nm or less, and 71 μm × 71 μm on the surface of the support. A step of setting the surface roughness (Sa) to 1 nm or more and 10 nm or less in a field of view of 95 μm ((1-1) surface polishing step of the support) and
A step of preparing a polyimide precursor composition containing a polyimide precursor and an organic solvent ((1-2) polyimide precursor composition preparation step) and
A step of applying the polyimide precursor composition to the surface of the support to form a coating film of the polyimide precursor composition ((1-3) a step of forming a coating film of the polyimide precursor composition).
A step of removing the organic solvent from the coating film of the polyimide precursor composition and imidizing the polyimide precursor contained in the coating film of the polyimide precursor composition ((1-4) coating of the polyimide precursor composition). A production method comprising a film drying step and (1-5) imidization step) can be mentioned.

(1-1) Surface Polishing Step of Support As the support, any material having a smooth surface and having heat resistance and solvent resistance can be used without particular limitation. Examples of the material of the support include an inorganic material such as a glass plate, a metal plate whose surface is mirror-treated, a synthetic resin, and the like.
The shape of the support is selected by the coating method, and may be, for example, a plate shape or a foil shape, a drum shape or a belt shape, a sheet shape that can be wound on a roll, or the like. .. From the viewpoint of continuous productivity such as roll-to-roll processing, the shape of the support is preferably sheet-like, foil-like, or the like.

The metal material constituting the metal plate is not particularly limited, but copper, SUS, aluminum, steel, nickel, a composite metal obtained by combining these, and the like can be used. Further, a material obtained by treating the surface of the above-mentioned metal material with another metal material such as zinc or a chromium compound can also be used as a support. Among these, SUS can be preferably used from the viewpoint of ease of use.
Further, as the metal material, for example, it is also possible to use a stainless steel BA material obtained by cold-rolling the above-mentioned SUS, performing a brilliant heat blunting treatment, and further performing a light cold-rolling treatment.

For example, when the support is in the form of a foil, copper foil, steel foil, SUS foil, aluminum foil, nickel foil and the like can be used without particular limitation. Further, a composite metal foil obtained by combining these, a metal foil treated with another metal such as zinc or a chromium compound, or the like can also be used. Among these, SUS foil can be preferably used from the viewpoint of ease of use.

The metal leaf can be used in various shapes such as a cut sheet shape, a roll shape, or an endless belt shape. The metal foil is preferably in the form of a roll.

When the support is a roll-shaped metal leaf or a sheet that can be wound around a roll, its length is not particularly limited.
When the support is a roll-shaped metal leaf or a sheet that can be wound around a roll, the width thereof is not particularly limited, but is preferably 100 mm or more and 3000 mm or less, preferably 300 mm or more and 2000 mm or less. It is more preferably 500 mm or more and 1500 mm or less, and particularly preferably 500 mm or more and 1300 mm or less.

When an inorganic material such as a glass plate or a synthetic resin is used as the material of the support, it is preferable to use a material having a glass transition temperature higher than the heating temperature in the drying step and the imidization step described later. Specifically, it is preferable to use an inorganic material or synthetic resin having a glass transition temperature of 60 ° C. or higher, more preferably 110 ° C. or higher.
By using a support having a glass transition temperature higher than the heating temperature in the drying step and the imidization step described later, the viscosity of the support becomes high when the heat treatment is performed in the drying step and the imidization step. It is possible to suppress a phenomenon in which the support rises excessively and the support is separated internally when the polyimide film is peeled from the support, and a part of the support adheres to the polyimide film.
The measurement of the glass transition temperature can be performed in the same manner as the measurement of the glass transition temperature described in the polyimide film.

In the surface polishing step of the support, by polishing the surface of the support described above, the surface of the support extends in a direction orthogonal to the longitudinal direction of the support in a field of view of 700 μm × 700 μm, and is described above. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (B1) arbitrarily extracted so that the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction, and the support. The surface of the second region (B2) arbitrarily extracted so that the width extending along the longitudinal direction of the body and the width in the direction orthogonal to the longitudinal direction is narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the swell (Wa2) is 20 nm or less, and the surface roughness (Sa) of the surface of the support in a field of view of 71 μm × 95 μm is 1 nm or more. It should be 10 nm or less.

The surface waviness (Wa1) of the first region (B1) of the support and its average value (Wa1 _ave ) are calculated, and the surface waviness (Wa2) of the second region (B2) of the support and its average value (Wa2) are calculated. The calculation of Wa2 _ave ) and the calculation of the surface roughness (Sa) of the support are the surface waviness (Wa1) of the first region (A1) of the polyimide film and its average value (Wa1), respectively, as described in the above-mentioned polyimide film. _Ave ) is calculated, the surface waviness (Wa2) of the second region (A2) of the polyimide film and its average value (Wa2 _ave ) are calculated, and the surface roughness (Sa) of the polyimide film is calculated in the same manner. Can be done.

From the viewpoint of suppressing the generation of streaks on the surface of the obtained polyimide film, the average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (B1) and the surface waviness of the second region (B2) (B2). The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of Wa2) is preferably 15 nm or less, more preferably 10 nm or less, and further preferably 5 nm or less.
Further, from the viewpoint of suppressing deterioration of the appearance of the surface of the obtained polyimide film, the average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (B1) and the surface of the second region (B2). The difference (Wa1 _ave − Wa2 _ave ) from the average value (Wa2 _ave ) of the swell (Wa2) is preferably −20 nm or more, and more preferably −10 nm or more.

The method for polishing the surface of the support can be appropriately selected according to the shape of the support, and can be performed by, for example, roll polishing, buffing, electrolytic abrasive grain polishing, or the like.

For example, when rolling a long windable support (for example, SUS foil), a polishing roll is placed between the unwinding roll that sends out the support and the winding roll that winds up the support. Polishing can be performed by moving the support while contacting the surface of the polishing roll so that the support scratches the surface of the rotating polishing roll, and winding the support with the take-up roll.
Further, the surface of the support may be polished by passing the support between the pressing roll and the polishing roll arranged so as to face the polishing roll.

In this case, the surface state of the support can be adjusted as described above by, for example, adjusting the surface pressure of the support with respect to the polishing roll, the tension applied to the support, and the moving speed of the support.
The surface pressure of the support is not particularly limited, but is preferably adjusted in the range of, for example, 0.1 to 10 kg / 500 mm, preferably 1 to 5 kg / 500 mm. The tension applied to the support is preferably adjusted in the range of 10 to 50 N / m. Further, it is preferable to adjust the moving speed of the support in the range of 5 to 40 m / min.

When buffing a long windable support (for example, SUS foil or stainless steel BA material), the following can be performed, for example.
First, the support is fixed to the support base of the polishing machine by a mechanical chuck or a vacuum chuck. Next, after applying a buff abrasive to the surface of the buff or the surface of the support, the buff is placed on a wide polishing head, and the buff is rotated at high speed while reciprocating the polishing head on the surface of the support. The surface can be polished by contacting them.

Further, when buffing a long windable support (for example, SUS foil or stainless steel BA material), the following can be performed, for example.
First, a support is placed on the surface of a transport member such as a transport belt, and then the support is moved in a certain direction by the transport member. Next, after applying a buff abrasive to the surface of the buff or the surface of the support, the buff is placed on a wide polishing head, and the buff is constantly rotated at a high speed with the polishing head fixed at a predetermined position. Surface polishing can be performed by bringing the buff into contact with the surface of the support that moves in the direction.

Examples of the buff include cotton buff, iron buff, sisal buff, nerbuff, felt buff and the like.
The types of buffs are classified into loose buffs, bias buffs, solid buffs, sewing buffs, fold buffs, etc., depending on the fiber direction and the laminated composition, and any of these can be used.
Among them, the bias buff can be preferably used because it is easy to adjust the thickness and the like. Further, the fold buff can be suitably used because the polishing strength can be adjusted by adjusting the folding condition of the fold.

The buffing agent is roughly classified into a solid buffing agent (rod-shaped buffing agent) and a liquid buffing agent, and any of them can be used.
Examples of the solid buff abrasive (rod-shaped buff abrasive) include oil-based solid buff abrasives and non-oil-based solid buff abrasives, but oil-based solid buff abrasives are generally used. The oil-based solid buffing agent is formed into a rod shape or the like by blending an appropriate amount of each of animal, vegetable or mineral oils and fats such as fatty acid, hydrogenated oil or pine oil and an abrasive. Can be used. As the abrasive, for example, tripoli, diatomaceous earth fine powder, iron oxide, alumina (calcined alumina, molten alumina fine powder), chromium oxide, diatomaceous earth and the like can be used.
Further, the particle size of the abrasive can be appropriately selected and used according to the intended use.

The weight ratio of oils and fats to the total amount of the rod-shaped buff abrasive (solid buff abrasive) is preferably 20 to 30% from the viewpoint of achieving both the lubricating action and the scattering prevention effect on the buff surface and the polishing ability. ..
The rod-shaped buffing agent (solid buffing agent) may be applied to the buff surface by hand by an operator or by using an automatic solid buffing agent applying device.

For example, when the above-mentioned oil-based solid buff abrasive is pressed against the surface of the buff, the oil and fat contained in the solid buff abrasive is melted by the frictional heat generated during the pressing, and the abrasive contained in the solid buff abrasive is used. Moves to the surface of the buff. When the surface of the buff is brought into contact with the support in such a state, an oil film of melted oil and fat is formed on the surface of the support. Therefore, it is possible to smoothly polish the surface of the support while preventing the polishing material from biting into the surface of the support.

The liquid buffing agent is, for example, an emulsion-type polishing agent obtained by mixing the same abrasives and oils and fats used in the above-mentioned solid buffing agent (rod-shaped buffing agent) with water and emulsifying them. It can be suitably used.
Further, as the liquid buffing agent, it is also possible to use, for example, a greasy or non-greasy type as a liquid buffing agent other than the emulsion type.

The weight ratio of the fats and oils to the total amount of the liquid buff abrasive is preferably 20 to 30% from the viewpoint of achieving both the lubricating action and the scattering prevention effect on the buff surface and the polishing ability.
The liquid buffing agent may be applied to the buff surface or the surface of the workpiece by spray application using an air spray, an airless spray, a pressure-increasing spray in a spray gun, or the like, or by brush coating or roll coating. May be good.

When buffing is performed, for example, the surface condition of the support is adjusted by adjusting the number of reciprocating movements of the polishing head, the transport speed of the transport member, and appropriately selecting the type and particle size of the abrasive to be mixed with the polishing agent. Can be adjusted as described above.
The number of reciprocating movements of the polishing head and the transport speed of the transport member may be appropriately adjusted according to the surface condition of the target support.

(1-2) Polyimide Precursor Composition Preparation Step The polyimide precursor composition prepared in the first production method contains a polyimide precursor and an organic solvent, and if necessary, contains additives and the like. May be.
The polyimide precursor is a polyamic acid obtained by polymerizing a tetracarboxylic acid component and a diamine component. In the first production method, the tetracarboxylic acid component and the diamine component used in the polyimide precursor are not particularly limited, and examples thereof include the above-mentioned tetracarboxylic acid component and the diamine component.

The number average molecular weight of the polyimide precursor is preferably 2000 or more, and more preferably 4000 or more, from the viewpoint of the strength of the film. On the other hand, if the number average molecular weight is too large, the viscosity becomes high and the workability may be deteriorated. Therefore, it is preferably 1,000,000 or less, and more preferably 500,000 or less.
The number average molecular weight of the polyimide precursor can be determined by NMR (for example, manufactured by BRUKER, AVANCE III). For example, a polyimide precursor solution is applied to a glass plate and dried at 100 ° C. for 5 minutes, then 10 mg of solid content is dissolved in 7.5 ml of a dimethyl sulfoxide-d6 solvent, NMR measurement is performed, and the mixture is bonded to an aromatic ring. The number average molecular weight can be calculated from the peak intensity ratio of hydrogen atoms.

Further, the polyimide precursor preferably has a weight average molecular weight of 2000 or more, and more preferably 4000 or more, from the viewpoint of strength when formed into a film. On the other hand, if the weight average molecular weight is too large, the viscosity becomes high and the workability such as filtration may be deteriorated. Therefore, it is preferably 1,000,000 or less, and more preferably 500,000 or less.
For the weight average molecular weight of the polyimide precursor, the polyimide precursor is prepared as a solution of N-methylpyrrolidone (NMP) having a concentration of 0.5% by weight, and the solution is filtered through a syringe filter (pore size: 0.45 μm) to develop the solution. As a solvent, a 10 mmol% LiBr-NMP solution having a water content of 500 ppm or less was used, and a GPC device (HLC-8120 manufactured by Tosoh Co., Ltd., detector: differential refractometer (RID) detector, column used: GPC LF-804 manufactured by SHODEX) was used. (Connected in series), the measurement is performed under the conditions of a sample injection amount of 50 μL, a solvent flow rate of 0.4 mL / min, a column temperature of 37 ° C., and a detector temperature of 37 ° C. The weight average molecular weight of the polyimide is a polystyrene standard sample having the same concentration as the sample (weight average molecular weight: 364,700, 204,000, 103,500, 44,360,27,500, 13,030, 6,300, 3, It is a conversion value with respect to the standard polystyrene measured with reference to 070). Compare the elution time with the calibration curve to determine the weight average molecular weight.

The polyimide precursor solution can be obtained by reacting the above-mentioned tetracarboxylic acid component and diamine component in an organic solvent.
The organic solvent used for the synthesis of the polyimide precursor (polyamic acid) is not particularly limited as long as the above-mentioned tetracarboxylic acid component and diamine component can be dissolved, and for example, an aprotonic polar solvent or a water-soluble alcohol solvent may be used. Can be used. In the present invention, among others, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, etc. It is preferable to use an organic solvent containing a nitrogen atom of γ-butyrolactone or the like. Among them, it is preferable to use an organic solvent containing a nitrogen atom, and it is more preferable to use N, N-dimethylacetamide, N-methyl-2-pyrrolidone or a combination thereof. The organic solvent is a solvent containing a carbon atom.
The polyimide precursor solution may be prepared by dissolving a pre-synthesized solid polyimide precursor in an organic solvent.

Further, when the polyimide precursor solution is prepared by combining two or more kinds of diamines, an acid dianhydride may be added to a mixed solution of two or more kinds of diamines to synthesize polyamic acid, or two kinds of diamines may be synthesized. The above diamine components may be added to the reaction solution step by step at an appropriate molar ratio to control the sequence in which each raw material is incorporated into the polymer chain to some extent.
When a diamine having one or two silicon atoms in the main chain is used, for example, one silicon atom or one silicon atom in the main chain is used in a reaction solution in which a diamine having one or two silicon atoms in the main chain is dissolved. By adding an acid dianhydride having a molar ratio of 0.5 equal to that of two diamines and reacting them, an amide reacted with a diamine having one or two silicon atoms in the main chain at both ends of the acid dianhydride. An acid may be synthesized, the remaining diamine may be added in whole or in part thereof, and an acid dianhydride may be added to polymerize the polyamic acid.
When polymerized by this method, a diamine having one or two silicon atoms in the main chain is introduced into the polyamic acid in a linked form via one acid dianhydride. Polymerizing a polyamic acid by such a method is from the viewpoint that the positional relationship of the amic acid having one or two silicon atoms in the main chain can be specified to some extent, and a film having excellent impact resistance and bending resistance can be easily obtained. preferable.

When synthesizing the polyimide precursor (polyamic acid), Y / X is 0.9 when the number of moles of the diamine component to be polymerized in the above-mentioned organic solvent is X and the number of moles of the tetracarboxylic acid component is Y. It is preferably 1.1 or more, more preferably 0.95 or more and 1.05 or less, further preferably 0.97 or more and 1.03 or less, and 0.99 or more and 1.01 or less. It is particularly preferable to do so. Within such a range, the molecular weight (degree of polymerization) of the polyamic acid obtained can be appropriately adjusted.
The procedure of the polymerization reaction can be appropriately selected and used by a known method, and is not particularly limited.

The polyimide precursor composition may be prepared by using the polyimide precursor solution obtained by the synthetic reaction as it is and mixing it with other components as needed, or drying the organic solvent of the polyimide precursor solution. It may be prepared by dissolving it in another organic solvent.

The polyimide precursor composition may contain an additive in the polyimide precursor solution, if necessary. As the additive, the same one as described in the above-mentioned polyimide film can be used.

The organic solvent used in the polyimide precursor composition is not particularly limited as long as the polyimide precursor can be dissolved. For example, it contains nitrogen atoms such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone. Organic solvents; γ-butylolactone; and mixed solvents thereof can be used, but among them, it is preferable to use an organic solvent containing a nitrogen atom.

The content of the polyimide precursor in the polyimide precursor composition is 50% by mass in the solid content of the polyimide precursor composition from the viewpoint of forming a polyimide film having a uniform coating film and handleable strength. The above is preferable, and more preferably 60% by mass or more, and the upper limit may be appropriately adjusted depending on the contained components.
The organic solvent in the polyimide precursor composition is preferably 40% by mass or more, more preferably 50% by mass or more in the polyimide precursor composition from the viewpoint of forming a uniform coating film and a polyimide film. It is preferably 99% by mass or less.

Further, it is preferable that the water content of the polyimide precursor composition is 1000 ppm or less because the storage stability of the polyimide precursor composition is improved and the productivity can be improved. If the polyimide precursor composition contains a large amount of water, the polyimide precursor may be easily decomposed.
The water content of the polyimide precursor composition can be determined using a Karl Fisher Moisture Meter (for example, Mitsubishi Chemical Corporation, trace moisture measuring device CA-200 type).

The viscosity of the polyimide precursor composition at 25 ° C. is preferably 500 cps or more and 100,000 cps or less from the viewpoint of forming a uniform coating film and a polyimide film.
The viscosity of the polyimide precursor composition can be measured using a viscometer (for example, TVE-22HT, Toki Sangyo Co., Ltd.) at 25 ° C. with a sample volume of 0.8 ml.

(1-3) Polyimide precursor composition coating film forming step The polyimide precursor composition is applied to the surface of the support whose surface has been polished in the surface polishing step of the support (1-1), and the polyimide is applied. A coating film of the precursor composition is formed.

The coating means is not particularly limited as long as it can be coated with a desired film thickness, and for example, known ones such as a die coater, a comma coater, a roll coater, a gravure coater, a curtain coater, a spray coater, and a lip coater can be used. ..
The coating may be performed by a single-wafer coating device or a roll-to-roll coating device.

(1-4) Polyimide precursor composition coating film drying step After the polyimide precursor composition is applied to the support, the temperature is 150 ° C. or lower, preferably 30 ° C. or higher and 120 ° C. until the coating film becomes tack-free. The organic solvent in the coating film is dried below. By setting the drying temperature of the organic solvent to 150 ° C. or lower, the imidization of the polyamic acid can be suppressed.

The drying time may be appropriately adjusted according to the film thickness of the polyimide precursor coating film, the type of organic solvent, the drying temperature, etc., but is usually 1 minute to 60 minutes, preferably 2 minutes to 30 minutes. Is preferable. If it exceeds the upper limit, it is not preferable from the viewpoint of the production efficiency of the polyimide film. On the other hand, if it is below the lower limit, the appearance of the obtained polyimide film may be affected by the rapid drying of the organic solvent.

The method for drying the organic solvent is not particularly limited as long as the organic solvent can be dried at the above temperature, and for example, an oven, a drying oven, a hot plate, infrared heating, or the like can be used.
When a high degree of control of optical properties is required, the atmosphere of the organic solvent during drying is preferably an inert gas atmosphere. The inert gas atmosphere is preferably a nitrogen atmosphere, preferably an oxygen concentration of 100 ppm or less, and more preferably 50 ppm or less. Heat treatment in the air can oxidize the film, causing it to color or reduce its performance.

(1-5) Imidization Step The polyimide precursor contained in the polyimide precursor composition is imidized. When the manufacturing method has a stretching step, the imidization step may be performed on the polyimide precursor in the polyimide precursor coating before the stretching step, or the polyimide precursor coating after the stretching step. It may be performed on the polyimide precursor inside, or on both the polyimide precursor in the polyimide precursor coating film before the stretching step and the polyimide precursor existing in the film after the stretching step. good.
In the first production method, the polyimide precursor is imidized by heating. The imidization temperature may be appropriately selected according to the structure of the polyimide precursor. Usually, the temperature rise start temperature is preferably 30 ° C. or higher, and more preferably 100 ° C. or higher. On the other hand, the temperature rise end temperature is preferably 250 ° C. or higher.
From the viewpoint of optical characteristics, moisture absorption, dimensional stability, solvent resistance, etc., it is preferable that the temperature rise end temperature is within the range of the glass transition temperature of the polyimide imimized with the polyimide precursor ± 30 ° C., and the polyimide glass. The transition temperature is more preferably within the range of ± 20 ° C., and the transition temperature is more preferably within the range of ± 15 ° C. of the glass transition temperature of the polyimide. If the imidization temperature is too high, the polyimide film may be colored by oxidation in the skeleton of the polyimide or the polyimide precursor, and if the imidization temperature is too low, the imidization may not proceed sufficiently. be.

The temperature rising rate is preferably appropriately selected depending on the film thickness of the obtained polyimide layer, and when the film thickness of the polyimide layer is thick, it is preferable to slow down the temperature rising rate.
From the viewpoint of the production efficiency of the polyimide film, the temperature is preferably 5 ° C./min or more, and more preferably 10 ° C./min or more. On the other hand, the upper limit of the temperature rising rate is usually 50 ° C./min, preferably 40 ° C./min or less, and more preferably 30 ° C./min or less. It is preferable to set the temperature rise rate from the viewpoint of suppressing poor appearance and decrease in strength of the film, controlling whitening due to the imidization reaction, and improving light transmission.

The temperature rise may be continuous or stepwise, but it is preferable to raise the temperature continuously from the viewpoints of suppressing poor appearance and strength deterioration of the film and controlling whitening associated with the imidization reaction. Further, the temperature rising rate may be constant or may be changed in the middle of the above-mentioned entire temperature range.

The atmosphere at the time of temperature rise of imidization is preferably an inert gas atmosphere. The inert gas atmosphere is preferably a nitrogen atmosphere, preferably an oxygen concentration of 500 ppm or less, more preferably 200 ppm or less, and even more preferably 100 ppm or less. Heat treatment in the air can oxidize the film, causing it to color or reduce its performance.
However, when 50% or more of the hydrogen atoms bonded to the carbon atoms contained in the polyimide are hydrogen atoms directly bonded to the aromatic ring, the influence of oxygen on the optical properties is small, and an inert gas atmosphere is not used. A polyimide having high light transmittance can be obtained.

The heating method for imidization is not particularly limited as long as the temperature can be raised at the above temperature, and for example, an oven, a heating furnace, infrared heating, electromagnetic induction heating or the like can be used.

Above all, it is more preferable to set the imidization ratio of the polyimide precursor to 50% or more before the stretching step. By setting the imidization ratio to 50% or more before the stretching step, even when stretching is performed after the step and then heating is performed at a higher temperature for a certain period of time to perform imidization, the appearance of the film may be poor. Whitening is suppressed. Above all, from the viewpoint of improving the impact resistance of the polyimide film, it is preferable to set the imidization ratio to 80% or more, further to 90% or more, and further to 100% in the imidization step before the stretching step. Is preferable. It is presumed that the impact resistance is improved by stretching after imidization because the rigid polymer chains are easily oriented.
The imidization rate can be measured by analyzing the spectrum by infrared measurement (IR) or the like.

In order to obtain the final polyimide film, it is preferable to proceed the reaction to 90% or more, further 95% or more, and further 100% of imidization.
In order to allow the reaction to proceed to 90% or more and even 100% of imidization, it is preferable to keep the temperature at the end temperature for a certain period of time, and the holding time is usually 1 minute to 180 minutes, further 5 minutes to 150 minutes. It is preferably a minute.

(1-6) Stretching Step The first manufacturing method includes a stretching step of stretching at least one of the polyimide precursor coating film and the imidized coating film obtained by imidizing the polyimide precursor coating film. You may. When the stretching step is provided, it is particularly preferable to include a step of stretching the coating film after imidization from the viewpoint of improving the surface hardness of the polyimide film.

In the first production method, it is preferable to carry out the step of stretching 101% or more and 10000% or less while heating at 80 ° C. or higher when the initial size before the stretching is set to 100%.
The heating temperature during stretching is preferably in the range of the glass transition temperature of the polyimide or the polyimide precursor ± 50 ° C., and preferably in the range of the glass transition temperature ± 40 ° C. If the stretching temperature is too low, the film may not be deformed and sufficient orientation may not be induced. On the other hand, if the stretching temperature is too high, the orientation obtained by stretching may be relaxed by the temperature, and sufficient orientation may not be obtained.
The stretching step may be performed at the same time as the imidization step. Imidization rate of 80% or more, further 90%
As described above, it is preferable to stretch the imidized coating film after imidization of 95% or more, particularly substantially 100%, from the viewpoint of improving the surface hardness of the polyimide film.

The draw ratio of the polyimide film is preferably 101% or more and 10000% or less.
More preferably, it is 101% or more and 500% or less. By stretching in the above range,
The impact resistance of the obtained polyimide film can be further improved.

The method for fixing the polyimide film at the time of stretching is not particularly limited, and is selected according to the type of stretching device and the like. Further, the stretching method is not particularly limited, and it is possible to stretch while passing through a heating furnace by using a stretching device having a transport device such as a tenter, for example. The polyimide film may be stretched in only one direction (longitudinal stretching or transverse stretching), or may be stretched in two directions by simultaneous biaxial stretching, sequential biaxial stretching, diagonal stretching, or the like.

(Second manufacturing method)
The method for producing a polyimide film of the present invention is, for example, as a second production method, in which the surface of a long support is polished so that the surface of the support has a field of view of 700 μm × 700 μm. The surface waviness of the first region (B1) arbitrarily extracted so as to extend in the direction orthogonal to the longitudinal direction and to have the width in the longitudinal direction narrower than the length in the direction orthogonal to the longitudinal direction (B1). The average value of Wa1) (Wa1 _ave ) and
A second region (B2) arbitrarily extracted so that the width extending along the longitudinal direction of the support and the width in the direction orthogonal to the longitudinal direction is narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the support is 20 nm or less, and the surface roughness (Sa) of the surface of the support in a field of view of 71 μm × 95 μm is set. A step of 1 nm or more and 10 nm or less ((2-1) surface polishing step of the support) and
A step of preparing a polyimide composition containing a polyimide and an organic solvent ((2-2) polyimide composition preparation step) and
A step of applying the polyimide composition to the surface of the support to form a coating film of the polyimide composition ((2-3) polyimide composition coating film forming step).
It comprises a step of forming a polyimide film by removing the organic solvent from the coating film of the polyimide composition ((2-4) step of drying the polyimide composition coating film).

The second production method can be preferably used when the polyimide to be used has a solvent solubility such that it dissolves in an organic solvent at 25 ° C. in an amount of 5% by mass or more.

In the second manufacturing method, the (2-1) surface polishing step of the support can be the same as the (1-1) surface polishing step of the support of the first manufacturing method. In addition, examples of the support used in the second manufacturing method include the same supports as those used in the first manufacturing method.
Hereinafter, in the second production method, a step of preparing a polyimide composition (hereinafter, referred to as (2-2) polyimide composition preparation step) and a step of forming a coating film of the polyimide composition (hereinafter, (2). -3) The step of forming the polyimide composition coating film) and the step of removing the organic solvent from the coating film of the polyimide composition (hereinafter referred to as (2-4) polyimide composition coating film drying step). This will be explained in detail.

(2-2) Polyimide Composition Preparation Step The polyimide used in the polyimide composition preparation step of the second manufacturing method has the above-mentioned solvent solubility from the same polyimides as described in the above-mentioned polyimide film. The polyimide to be possessed can be selected and used. As a method for imidization, it is preferable to use chemical imidization using a chemical imidizing agent instead of heat dehydration for the dehydration ring closure reaction of the polyimide precursor. When performing chemical imidization, known compounds such as amines such as pyridine and β-picolinic acid, carbodiimides such as dicyclohexylcarbodiimide, and acid anhydrides such as acetic anhydride may be used as the dehydration catalyst.
The acid anhydride is not limited to acetic anhydride, and examples thereof include propionic acid anhydride, n-butyric acid anhydride, benzoic acid anhydride, and trifluoroacetic anhydride, but the acid anhydride is not particularly limited. At that time, a tertiary amine such as pyridine or β-picolinic acid may be used in combination. However, since these amines deteriorate the optical properties, especially the yellowness (YI value) when they remain in the film, the reaction solution reacted from the precursor to the polyimide is not cast as it is to form a film. It is preferable to purify by reprecipitation or the like to remove components other than polyimide to 100 ppm or less of the total weight of the polyimide before forming a film.

The polyimide used in the polyimide composition preparation step of the second production method is not necessarily limited to imidized by chemical imidization using a chemical imidizing agent, but is imidized by heat dehydration. Can also be used.

As the organic solvent used in the polyimide composition preparation step of the second production method, the same one as described in the polyimide precursor composition preparation step of the first production method can be used.

The polyimide composition may contain an additive, if necessary. As the additive, the same additive as described in the polyimide precursor composition preparation step in the first production method can be used.

The preferred range of the polyimide content in the polyimide composition may be the same as the preferred range of the polyimide precursor content in the polyimide precursor composition, and the water content of the polyimide composition may be the same. A suitable range of the amount may be the same as a suitable range of the water content of the polyimide precursor composition, and a suitable range of the viscosity of the polyimide composition at 25 ° C. is the polyimide precursor composition. May be similar to the preferred range of viscosity at 25 ° C.

(2-3) Polyimide composition coating film forming step In the polyimide composition coating film forming step, the polyimide composition is applied to the surface of the support surface-polished in the surface polishing step of the support, and the above-mentioned Form a coating film of the polyimide composition.
In the polyimide composition coating film forming step in the second manufacturing method, the same coating method as described in the polyimide precursor composition coating film forming step in the first manufacturing method can be used.

(2-4) Polyimide Composition Coating Drying Step The drying method in the polyimide composition coating drying step in the second manufacturing method was described in the polyimide precursor composition coating drying step in the first manufacturing method. The same thing as the one can be used.
In the polyimide composition coating film drying step, the drying temperature is preferably 80 ° C. or higher and 150 ° C. or lower under normal pressure. Under reduced pressure, the temperature is preferably in the range of 10 ° C. or higher and 100 ° C. or lower.
The drying time and the atmosphere at the time of drying in the polyimide composition coating film drying step may be the same as the drying time and the atmosphere at the time of drying described in the polyimide precursor composition coating film drying step of the first production method. ..

(2-5) Stretching Step Further, the second manufacturing method may include a stretching step of stretching the laminate of the polyimide composition coating film after forming all the polyimide composition coating films. The stretching step can be the same as the stretching step in the first manufacturing method.

Further, in the method for producing a polyimide film of the present invention, the polyimide film obtained by the above-mentioned step may be subjected to surface treatment such as saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet treatment, flame treatment and the like. ..

According to the method for producing a polyimide film of the present invention described above, it is possible to obtain a polyimide film having the same characteristics as those described in the polyimide film.

According to the method for producing a polyimide film of the present invention, it is possible to obtain a polyimide film which exhibits excellent adhesion to a functional layer, has a good appearance, and has excellent optical characteristics.

IV. Method for Manufacturing Laminates The method for manufacturing a laminate of the present invention includes a step of preparing a polyimide film obtained by the above-mentioned method for manufacturing a polyimide film of the present invention (hereinafter referred to as a polyimide film preparation step) and a step of preparing the polyimide film. A step of forming a coating film of the composition for forming a functional layer on the surface in contact with the support (hereinafter referred to as a coating film forming step for a functional layer) and a step of curing the coating film (hereinafter referred to as a coating film). The curing process) and.

Since the method for producing the laminate of the present invention uses the polyimide film obtained by the above-mentioned production method of the present invention, the produced laminate has a surface and a functional layer on the side of the polyimide film in contact with the support. Has excellent adhesion, has a good appearance, and has excellent optical characteristics.

(1) Polyimide Film Preparation Step In the method for manufacturing a laminate of the present invention, the above-mentioned method for manufacturing a polyimide film of the present invention can be used in the step of preparing a polyimide film, and thus the description thereof is omitted here.

(2) Functional layer coating film forming step In the functional layer coating film forming step in the method for producing a laminated body of the present invention, the functional layer is formed on the surface of the polyimide film described above in contact with the support. Form a coating film of the composition.
Examples of the composition for forming a functional layer include a composition for forming a hard coat layer, which is laminated to improve the surface hardness of a polyimide film.

The composition for forming a hard coat layer contains at least one of a radically polymerizable compound and a cationically polymerizable compound, and if necessary, further contains other components such as a polymerization initiator, a solvent and an additive. be able to.

Here, as the radically polymerizable compound, the cationically polymerizable compound, the polymerization initiator and the additive contained in the composition for forming the hard coat layer, the same ones as described in the above hard coat layer can be used. , The solvent can be appropriately selected from known solvents and used.

As a method of forming the coating film of the composition for forming the hard coat layer on at least the surface of the polyimide film on the side in contact with the support, for example, the surface of the polyimide film on at least the side in contact with the support. In addition, a method of applying the composition for forming a hard coat layer by a known coating means can be mentioned.
The coating means is not particularly limited as long as it can be coated with a target film thickness, and is, for example,
Examples thereof include the same means as those for applying the polyimide precursor composition to the support.
The coating film of the composition for forming the hard coat layer may be formed only on the surface of the polyimide film that is in contact with the support, or may be formed on both sides of the polyimide film.

The solvent is removed by drying the coating film of the curable composition for the hard coat layer, if necessary. Examples of the drying method include vacuum drying, heat drying, and a method of combining these drying methods. When drying at normal pressure, it is preferable to dry at 30 ° C. or higher and 110 ° C. or lower.

(3) Coating film curing step As a composition for forming a functional layer, for example, the curable composition for a hard coat layer is applied and dried as necessary, and radical polymerization contained in the curable composition is applied to the coating film. Depending on the polymerizable group of the sex compound and the cationically polymerizable compound, the coating film is cured by at least one of light irradiation and heating, whereby radical polymerization is carried out on at least the surface of the polyimide film on the side in contact with the support. A hard coat layer containing at least one polymer of a sex compound and a cationically polymerizable compound can be formed.

Ultraviolet rays, visible light, electron beams, ionizing radiation and the like are mainly used for light irradiation. In the case of ultraviolet curing, ultraviolet rays emitted from light rays such as ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, and metal halide lamps are used. The irradiation amount of the energy radiation source is about 50 to 5000 mJ / cm ² as the integrated exposure amount at the ultraviolet wavelength of 365 nm.
When heating, it is usually treated at a temperature of 40 ° C. or higher and 120 ° C. or lower. Also, room temperature (2)
The reaction may be carried out by leaving it at 5 ° C.) for 24 hours or more.

Further, the method for producing a laminated body of the present invention comprises, for example, a step of further forming another layer such as a gel containing urethane or an acrylic resin, and a known surface treatment as long as the effect of the present invention is not impaired. It may include a step of applying.

The hard coat layer may be formed by imparting functions such as antireflection property and antiglare property. The function can be imparted, for example, by subjecting the hardcoat layer to a known surface treatment, or by incorporating an additive such as an inorganic or organic fine particle into the curable composition for the hardcoat layer.

Further, in the above-described method for manufacturing a laminated body, a case where a hard coat layer is formed as a functional layer has been described as an example, but the functional layer is not necessarily limited to the hard coat layer. For example, an antireflection layer and an antiglare layer may be formed as the functional layer, or a primer layer for improving the adhesion between the polyimide film and the hardcoat layer may be formed.
Further, the functional layer may be formed as a single layer or may be formed as a plurality of layers. Further, the functional layer may be formed as a layer having a single function or may be formed as a layer having different functions from each other.

V. Surface material for display The surface material for display of the present invention is the polyimide film of the present invention described above or the laminate of the present invention described above.

The surface material for a display of the present invention is arranged and used so as to be located on the surface of various displays.
Similar to the above-mentioned laminate of the present invention, the surface material for a display of the present invention has excellent adhesion between the first surface of the polyimide film and the functional layer, has a good appearance, and has optical characteristics. Therefore, it can be particularly preferably used for a flexible display.
Further, the surface material for a display of the present invention, like the polyimide film of the present invention described above, exhibits excellent adhesion to the functional layer, has a good appearance, and has excellent optical characteristics. It can be particularly preferably used for a flexible display.

Further, the method for arranging the surface material for a display of the present invention on the surface of a display is not particularly limited, and examples thereof include a method via an adhesive layer. As the adhesive layer, a conventionally known adhesive layer that can be used for adhering a surface material for a display can be used.

VI. Method for Manufacturing Surface Material for Display The method for manufacturing a surface material for display of the present invention is a step of manufacturing a polyimide film by the above-mentioned manufacturing method of the present invention, or a step of manufacturing a laminate by the above-mentioned manufacturing method of the present invention. including. That is, the surface material for a display obtained by the manufacturing method of the present invention is a polyimide film obtained by the manufacturing method of the present invention described above, or a laminate obtained by the manufacturing method of the present invention described above.

The surface material for a display obtained by the manufacturing method of the present invention is arranged and used so as to be located on the surface of various displays.
The surface material for a display obtained by the manufacturing method of the present invention has excellent adhesion between the first surface of the polyimide film and the functional layer, similarly to the laminate obtained by the manufacturing method of the present invention described above. Moreover, since it has a good appearance and excellent optical characteristics, it can be suitably used for a flexible display.
Further, the surface material for a display obtained by the manufacturing method of the present invention exhibits excellent adhesion to a functional layer and has a good appearance, similar to the polyimide film obtained by the manufacturing method of the present invention described above. Since it has excellent optical characteristics, it can be suitably used for flexible displays.

Further, as a method of arranging the display surface material obtained by the manufacturing method of the present invention on the surface of the display, it can be performed in the same manner as described in the above-mentioned display surface material.

The surface material for a display of the present invention and the surface material for a display obtained by the manufacturing method of the present invention can be used for various known displays, and are not particularly limited. It can be used for displays and the like.

When the surface material for a display of the present invention and the surface material for a display obtained by the manufacturing method of the present invention are the laminate of the present invention, the outermost surface after being arranged on the surface of the display is a polyimide film. It may be the surface on the side or the surface on the hard coat layer side, but it is preferable to arrange the surface material for a display of the present invention so that the surface on the hard coat layer side is the outermost surface. Further, the display surface material of the present invention and the display surface material obtained by the production method of the present invention may have a fingerprint adhesion prevention layer on the outermost surface.

VII. Touch panel member The touch panel member of the present invention comprises the polyimide film of the present invention described above, a transparent electrode composed of a plurality of conductive portions arranged on one surface side of the polyimide film, and at least one side of an end portion of the conductive portion. It comprises a plurality of electrically connected take-out wires.

4 (A) and 4 (B) are schematic plan views of the touch panel member 10 of the present invention, and FIG. 5 shows AA of the touch panel member 10 shown in FIGS. 4 (A) and 4 (B). ´Line cross section.
As shown in FIG. 5, the touch panel member 10 of the present invention is formed on the polyimide film 1 of the present invention described above, the functional layer 2 laminated in contact with the first surface 11 of the polyimide film 1, and the functional layer 2. It has a first transparent electrode 4 arranged in contact with it. That is, the first transparent electrode 4 is arranged on the first surface 11 of the polyimide film 1 via the functional layer 2.

Further, the touch panel member 10 is further arranged in contact with the hard coat layer 3 laminated in contact with the second surface 12 on the side opposite to the first surface 11 of the polyimide film 1 and the hard coat layer 3. It has a second transparent electrode 5. That is, the second transparent electrode 5 is arranged on the second surface 12 of the polyimide film 1 via the hard coat layer 3.
As the functional layer 2, the same one as described in the above-mentioned "I. Laminated body" section can be used.

FIG. 4A is a schematic plan view of the touch panel member 10 on the first surface 11 side of the polyimide film 1, and FIG. 4B is a touch panel member on the second surface 12 side of the polyimide film 1. It is a schematic plan view of 10.
As shown in FIG. 4A, the touch panel member 10 is placed on the functional layer 2 laminated in contact with the first surface 11 of the polyimide film 1 in a direction orthogonal to the longitudinal direction of the polyimide film 1 (FIG. 4 (A). A plurality of strip-shaped electrode pieces (hereinafter referred to as the first conductive portion 41) extending so as to extend in the middle X-axis direction) are formed in the longitudinal direction of the polyimide film 1 (the middle Y-axis in FIG. 4A). The first transparent electrode 4 is formed by the plurality of first conductive portions 41, which are arranged at predetermined intervals in the direction). That is, the first transparent electrode 4 is configured such that the first conductive portion 41 and the first non-conductive portion 42 are alternately arranged in the longitudinal direction of the polyimide film 1.

A first take-out wire 7 that is electrically connected to the first conductive portion 41 is connected to the first conductive portion 41 at any one of its longitudinal end portions. The first take-out line 7 is any of the four sides of the polyimide film 1 and any of the two sides extending in the direction parallel to the longitudinal direction of the first conductive portion 41 (in FIG. 4A, the polyimide film). It extends to the edge 13) of 1. That is, the first take-out wire 7 is a polyimide film on either side of the longitudinal end portions of the plurality of second conductive portions 51, which will be described later, formed on the second surface 12 side of the polyimide film 1. It can be a long wiring extending to the end edge 13 of 1.

A first terminal 71 for electrically connecting to an external circuit may be provided at the end of the first take-out wire 7 extending to the end edge 13 of the polyimide film 1.

The first conductive portion 41 and the first take-out line 7 are generally connected in an inactive area 15 located outside the active area 14 visible to the user of the touch panel.
For the connection between the first conductive portion 41 and the first take-out wire 7, for example, as shown in FIG. 4A, a connection structure in which the connecting portion 16 is interposed can be adopted. Specifically, the connecting portion 16 can be formed by extending a layer of the conductive material from the longitudinal end portion of the first conductive portion 41 to a predetermined position in the inactive area 15. Further, by superimposing at least a part of the first take-out wire 7 on the connection portion 16, a connection structure between the first conductive portion 41 and the first take-out wire 7 can be formed. In this way, by adopting the connection structure having the connection portion 16, the first take-out line 7 and the first conductive portion 41 are surely connected, and the first take-out line 7 is in the inactive area 15. It is possible to suppress entry.

The connection between the first conductive portion 41 and the first take-out wire 7 is not limited to the structure forming the connecting portion 16 as shown in FIG. 4A. For example, although not shown, the longitudinal end of the first conductive portion 41 is extended to the inactive area 15, and in the inactive area 15, the first conductive portion 41 is extended to the inactive area 15. The two may be electrically connected by riding the first take-out wire 7 on the end portion.
In addition, in FIG. 4A, one of the longitudinal end portions of the first conductive portion 41 and the first take-out wire 7 are connected to each other, but in the present invention, one first is The first take-out wire 7 may be electrically connected to both ends of one conductive portion 41 in the longitudinal direction.

As shown in FIG. 4B, the touch panel member 10 is placed on the hard coat layer 3 laminated in contact with the second surface 12 of the polyimide film 1 in the longitudinal direction of the polyimide film 1 (in FIG. 4B). A plurality of strip-shaped electrode pieces (hereinafter referred to as the second conductive portion 51) extending so as to extend in the Y-axis direction) are orthogonal to the longitudinal direction of the polyimide film 1 (X in FIG. 4B). The second transparent electrode 5 is formed by the plurality of second conductive portions 51, which are arranged at predetermined intervals in the axial direction). That is, the second transparent electrode 5 is configured such that the second conductive portion 51 and the second non-conductive portion 52 are alternately arranged in the lateral direction of the polyimide film 1.

A second take-out wire 8 that is electrically connected to the second conductive portion 51 is connected to the second conductive portion 51 at one of its longitudinal end portions.
The second take-out wire 8 extends to the position of the end edge 13 of the polyimide fill 1 where the first take-out wire 7 described above does not overlap with the first terminal 71 among the four sides of the polyimide film 1. It has been extended. That is, the second take-out line 8 is one of the second take-out lines 8 at the end portion on the end edge 13 side of the polyimide film 1 described above among the longitudinal end portions of the plurality of second conductive portions 51. It is possible to form a short wiring in which the other end portion of the second take-out wire 8 is extended to the end edge 13 of the polyimide film 1 while electrically connecting the end portions of the second take-out wire 8.

A second terminal 81 for electrically connecting to an external circuit may be provided at the end of the second take-out wire 8 extending to the end edge 13 of the polyimide film 1.

The electrical connection between the second conductive portion 51 and the second take-out wire 8 shall be the same as the electrical connection between the first take-out wire 7 and the first conductive portion 41. Therefore, the description here is omitted.

The pattern in which the first take-out wire 7 is a long wiring and the second take-out wire 8 is a short wiring as shown in FIGS. 4A and 4B is an embodiment of the touch panel member 10 of the present invention. For example, it is possible to use a pattern in which the first take-out wire 7 is a short wiring and the second take-out wire 8 is a long wiring.
Further, the first take-out wire 7 may be connected to any end of the longitudinal end of the first conductive portion 41, and the second take-out wire 8 may be connected to any end of the second conductive portion 51. It may be connected to any end of the longitudinal end. Further, the extension direction of the first take-out line 7 and the extension direction of the second take-out line 8 are not limited to the directions shown in FIGS. 4A and 4B, and can be arbitrarily designed.

The patterns of the first conductive portion 41 and the second conductive portion 51 shown in FIGS. 4A and 4B do not limit the configuration of the touch panel member 10 of the present invention.
The first conductive portion 41 and the second conductive portion 51 are electrodes formed on the surface of the polyimide film 1 or the surface of another layer such as the functional layer 2 formed on the polyimide film 1. , If the touch panel member 10 constitutes a transparent electrode, it may be appropriately selected and applied. For example, any pattern of a transparent electrode capable of detecting a change in electric capacity due to contact with a finger or the like or a state close to contact by a capacitance method can be appropriately selected and applied. For example, electrode pieces having a circular shape or a diamond shape are arranged, and the first conductive portion 41 is in the X-axis direction and the second conductive portion 51 is in the Y-axis in a predetermined direction (in FIGS. 4A and 4B). In the direction), a plurality of conductive portions may be formed by connecting the electrode elements so as to be electrically connected, and the transparent electrode may be formed by the conductive portions.

Since the first conductive portion 41 constituting the first transparent electrode 4 and the second conductive portion 51 constituting the second transparent electrode 5 are mainly provided in the active area 14 of the touch panel member 10, light transmission is transmitted. Formed from the material of.
The first conductive portion 41 and the second conductive portion 51 are generally indium tin oxide-based transparent electrode materials containing indium tin oxide (ITO), indium oxide, indium zinc oxide (IZO) and the like as main constituents. It can be formed by using a transparent conductive film containing tin oxide (SnO ₂ ), zinc oxide (ZnO) or the like as a main component, or a conductive polymer compound such as polyaniline or polyacetylene. However, the materials of the first conductive portion 41 and the second conductive portion 51 are not limited to the above-mentioned materials.

The thicknesses of the first conductive portion 41 and the second conductive portion 51 are not particularly limited, but are generally used when the first conductive portion 41 and the second conductive portion 51 are formed by a photolithography method, for example. Specifically, it can be formed to be about 10 nm to 500 nm. Further, the first conductive portion 41 and the second conductive portion 51 may be formed by using the same kind of conductive materials as each other, or may be formed by using different materials. In particular, it is preferable to form the first conductive portion 41 and the second conductive portion 51 using the same kind of conductive material from the viewpoint of more effectively suppressing the occurrence of warpage and distortion of the touch panel member 10.

Since the first take-out line 7 and the second take-out line 8 are generally formed in the inactive area 15, the conductive material constituting them may or may not have light transmission. Generally, the first take-out wire 7 and the second take-out wire 8 can be formed by using a metal material such as silver or copper having high conductivity.
Specific examples of the metal material constituting the first take-out wire 7 and the second take-out wire 8 include a simple substance of a metal, a composite of metals, a composite of a metal and a metal compound, and a metal alloy.
Examples of the simple substance of metal include silver, copper, gold, chromium, platinum, and simple substance of aluminum. As the metal complex, MAM (Mo-Al-Mo, that is, a three-layer structure of molybdenum, aluminum, and molybdenum) and the like can be exemplified. As the composite of the metal and the metal compound, a chromium oxide / chromium laminate or the like can be exemplified. As the metal alloy, silver alloys and copper alloys are widely used. Further, as the metal alloy, APC (Au, Pd, Cu, that is, silver, palladium, copper) and the like can be exemplified.

In the first take-out line 7 and the second take-out line 8, a resin component may be appropriately mixed with the above-mentioned metal material.
For example, when the first take-out line 7 and the second take-out line 8 are formed by a photolithography method, an APC material made of silver, platinum, and copper is widely used as the forming material, but the first take-out line is used. The method for forming the wire 7 and the second take-out wire 8 is not limited to this.
For example, when the first take-out line 7 and the second take-out line 8 are formed by a printing method such as screen printing, metal particles such as silver and copper having a particle size of several tens of nm to several μm and a resin are used. A metal particle-containing paste prepared by blending a binder with a solvent to an appropriate concentration is widely used, but is not limited thereto. As the resin binder to be blended in the metal particle-containing paste, for example, a resin material such as epoxy resin, polyester resin, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, and polystyrene may be used alone or a mixture of two or more of these resin materials. It can be used as a mixture.

As described above, the first terminal 71 and the second terminal 81 are provided at the ends of the first take-out line 7 and the second take-out line 8. Therefore, the first terminal 71 and the second terminal 81 are made of a material for forming the first take-out wire 7 and the second take-out wire 8 in the process of forming the first take-out wire 7 and the second take-out wire 8. It can be formed using the same material as. The first terminal 71 and the second terminal 81 can be formed in a process different from the process of forming the first take-out wire 7 and the second take-out wire 8.
The thickness and width of the first take-out line 7 and the second take-out line 8 are not particularly limited, but for example, when the first take-out line 7 and the second take-out line 8 are formed by a photolithography method. Generally, the thickness is formed to be about 10 nm to 1000 nm, and the width dimension is formed to be about 5 μm to 200 μm.
The thickness and width of the first take-out line 7 and the second take-out line 8 are not particularly limited, but the first take-out line 7 and the second take-out line 8 are formed by printing such as screen printing. In this case, the thickness is generally formed to be about 5 μm to 20 μm, and the width dimension is formed to be about 20 μm to 300 μm.

The touch panel member of the present invention is not limited to the form shown in FIGS. 4 to 5, and as shown in FIGS. 6 to 7, for example, the first transparent electrode 4 and the second transparent electrode 5 are separate polyimides. It may be configured by being laminated on a film.
The touch panel member 20 shown in FIG. 7 includes a first polyimide film 1a, which is the polyimide film of the present invention described above, a functional layer 2a laminated in contact with the first surface 11 of the first polyimide film 1a, and a second. A plurality of hard coat layers 3a laminated in contact with the second surface 12 of one polyimide film 1a and a plurality of layers arranged on the first surface 11 of the first polyimide film 1a via the functional layer 2a. A first laminated body 201 having a first transparent electrode 4 composed of a strip-shaped electrode piece (first conductive portion 41), and a second polyimide film 1b which is the above-mentioned polyimide film of the present invention. , The functional layer 2b laminated in contact with the first surface 11 of the second polyimide film 1b, the hard coat layer 3b laminated in contact with the second surface 12 of the second polyimide film 1b, and the second. A second transparent electrode 5 composed of a plurality of strip-shaped electrode pieces (second conductive portion 51) arranged via a functional layer 2b on the first surface 11 of the polyimide film 1b of the above. The second laminate 202 and the like are provided.
As the functional layers 2a and 2b, the same ones as described in the above-mentioned "I. Laminated body" section can be used.

In the touch panel member 20, as shown in FIG. 7, the hard coat layer 3a of the first laminated body 201 and the second transparent electrode 5 of the second laminated body 202 are bonded to each other via the adhesive layer 6. It is configured. As the adhesive layer 6, a conventionally known adhesive layer that can be used for adhering various layers such as a hard coat layer and a transparent electrode can be used.

6 (A) is a schematic plan view of the first laminated body 201, and FIG. 6 (B) is a schematic plan view of the second laminated body 202.
7 is A in FIGS. 6A and 6B of a touch panel member formed by laminating the laminate 201 shown in FIG. 6A and the laminate 202 shown in FIG. 6B. It is sectional drawing at the position shown by -A'line.
As shown in FIG. 6A, the first conductive portion 41 of the first laminated body 201 is electrically connected to the first conductive portion 41 at any one of its longitudinal end portions. The first take-out line 7 is connected. As shown in FIG. 6A, a first terminal 71 for electrically connecting to an external circuit may be provided at the end of the first take-out wire 7.
Further, as shown in FIG. 6B, the second conductive portion 51 of the second laminated body 202 is electrically connected to the second conductive portion 51 at one of its longitudinal end portions. The second take-out line 8 is connected. As shown in FIG. 6B, a second terminal 81 for electrically connecting to an external circuit may be provided at the end of the second take-out wire 8.

The configuration and constituent materials of the first transparent electrode 4, the first take-out wire 7, and the first terminal 71 in the first laminated body 201 are the first in the touch panel member 10 shown in FIG. 4 (A). The same can be applied to the configuration and constituent materials of the transparent electrode 4, the first take-out wire 7, and the first terminal 71.
Further, the configuration and constituent materials of the second transparent electrode 5, the second take-out wire 8 and the second terminal 81 in the second laminated body 202 are the second in the touch panel member 10 shown in FIG. 4 (B). The same can be applied to the configuration and constituent materials of the transparent electrode 5, the second take-out wire 8 and the second terminal 81. Therefore, these detailed explanations will be omitted.

In FIGS. 4 to 7, the first transparent electrode 4 and the second transparent electrode 5 are both functional layers 2 and 2a on the first surface 11 of the polyimide film of the present invention described above. Alternatively, although the configuration shown is arranged via 2b or the hard coat layer 3, in the touch panel member of the present invention, the first transparent electrode 4 and the second transparent electrode 5 are in contact with the surface of the polyimide film. It may be arranged.
Further, FIGS. 4 to 7 show a form having the functional layers 2, 2a or 2b laminated in contact with the first surface 11 of the polyimide film of the present invention described above, but the touch panel member of the present invention is , It is not always necessary to have a functional layer laminated in contact with the first surface of the polyimide film.

The touch panel member of the present invention described above is arranged and used so as to be located on the surface of various displays.
The touch panel member of the present invention is flexible because the polyimide film of the present invention contained in the touch panel member exhibits excellent adhesion to the functional layer, has a good appearance, and has excellent optical characteristics. It can be particularly preferably used for a display.
Further, when the touch panel member of the present invention has a functional layer laminated in contact with the first surface of the polyimide film of the present invention contained in the touch panel member, the polyimide film and the functional layer have excellent adhesion. Since it has properties, has a good appearance, and has excellent optical characteristics, it can be particularly preferably used for a flexible display.

VIII. Liquid crystal display device The liquid crystal display device of the present invention has a liquid crystal display unit having a liquid crystal layer formed between substrates arranged opposite to each other and the polyimide film of the present invention arranged on one side of the liquid crystal display unit. And have.

FIG. 8 is a schematic cross-sectional view showing an example of the liquid crystal display device 100 of the present invention.
The liquid crystal display device 100 is a functional layer laminated in contact with the liquid crystal display unit 30, the touch panel member 10, the adhesive layer 6, the polyimide film 1 of the present invention described above, and the first surface 11 of the polyimide film 1. 2 and 2 are laminated in this order.
The touch panel member 10 included in the liquid crystal display device 100 has the same configuration as the touch panel member 10 shown in FIGS. 4 to 5. That is, the liquid crystal display device 100 has the polyimide film 1 of the present invention and the functional layer 2 laminated in contact with the first surface 11 of the polyimide film 1 in the touch panel member 10.

Although not shown, the liquid crystal display unit 30 has a liquid crystal layer formed between the substrates arranged so as to face each other. The liquid crystal display unit 30 may further have a colored layer of a plurality of colors and a light-shielding unit that defines pixels between the substrates arranged opposite to each other. Further, the liquid crystal display unit 30 may have a backlight unit having a light emitting element or a phosphor at a position on the outside of the substrate arranged opposite to each other on the side opposite to the touch panel member 10. Further, a polarizing plate may be provided on the outer surface of the substrates arranged so as to face each other.

The liquid crystal display device of the present invention is not limited to the form shown in FIG. 8, for example, as shown in FIG. 9, the first transparent electrode 4 and the second transparent electrode 5 are on separate polyimide films. It may be provided with the touch panel member 20 arranged and configured in.
FIG. 9 is a schematic cross-sectional view showing an example of the liquid crystal display device 200 of the present invention. The liquid crystal display device 200 is a functional layer laminated in contact with the liquid crystal display unit 30, the touch panel member 20, the adhesive layer 6, the polyimide film 1 of the present invention described above, and the first surface 11 of the polyimide film 1. 2 and 2 are laminated in this order.
The touch panel member 20 included in the liquid crystal display device 200 has the same configuration as the touch panel member 20 shown in FIGS. 6 to 7. That is, the liquid crystal display device 200 is in contact with the first polyimide film 1a, which is the polyimide film of the present invention, and the first surface 11 of the first polyimide film 1a in the first laminated body 201 of the touch panel member 20. In the second laminated body 202 of the touch panel member 20, the second polyimide film 1b, which is the polyimide film of the present invention, and the second polyimide film 1b, which are laminated with each other, are provided. It has a functional layer 2b laminated in contact with one surface 11.
Since the configuration of the liquid crystal display unit 30 is the same as that of the liquid crystal display unit 30 shown in FIG. 8, detailed description thereof will be omitted.

8 to 9 show a configuration in which the polyimide film of the present invention is arranged on the liquid crystal display unit 30 via the hard coat layer 3 and the second transparent electrode 5, or the hard coat layer 3b. However, the liquid crystal display device of the present invention may have a configuration in which the polyimide film of the present invention is arranged in contact with the liquid crystal display unit 30.

In the liquid crystal display device of the present invention, the polyimide film of the present invention contained in the liquid crystal display device exhibits excellent adhesion to the functional layer, has a good appearance, and is excellent in optical characteristics. Suitable as a liquid crystal display. Further, when the liquid crystal display device of the present invention has a functional layer laminated in contact with the first surface of the polyimide film of the present invention contained in the liquid crystal display device, the polyimide film and the functional layer are excellent. It is suitable as a liquid crystal display because it has good adhesion, has a good appearance, and has excellent optical characteristics.

IX. Organic electroluminescence display device The organic electroluminescence display device of the present invention is arranged on one side of an organic electroluminescence display unit having an organic electroluminescence layer formed between substrates arranged opposite to each other and the organic electroluminescence display unit. It has the above-mentioned electroluminescent film of the present invention.

FIG. 10 is a schematic cross-sectional view showing an example of the organic electroluminescence display device of the present invention.
The organic electroluminescence display device 300 is laminated in contact with the organic electroluminescence display unit 40, the touch panel member 10, the adhesive layer 6, the polyimide film 1 of the present invention described above, and the first surface 11 of the polyimide film 1. The functional layers 2 are laminated in this order.
The touch panel member 10 included in the organic electroluminescence display device 300 has the same configuration as the touch panel member 10 shown in FIGS. 4 to 5. That is, the organic electroluminescence display device 300 has the polyimide film 1 of the present invention and the functional layer 2 laminated in contact with the first surface 11 of the polyimide film 1 in the touch panel member 10.

Although not shown, the organic electroluminescence display unit 40 has an organic electroluminescence layer formed between the substrates arranged so as to face each other. The organic electroluminescence display unit 40 further comprises a support substrate, an organic EL element including an anode layer and a cathode layer sandwiching the organic EL layer, and a sealing base material for sealing the organic EL element. You may have.
The organic EL layer may be any one having at least an organic EL light emitting layer, and for example, from the anode layer side, a hole injection layer, a hole transport layer, an organic EL light emitting layer, an electron transport layer, and an electron injection. Those having a structure in which the layers are laminated in this order can be used.

The organic electroluminescence display device of the present invention is not limited to the form shown in FIG. 10, and as shown in FIG. 11, for example, the first transparent electrode 4 and the second transparent electrode 5 are separate polyimide films. It may be provided with the touch panel member 20 arranged and configured on the surface.
FIG. 11 is a schematic cross-sectional view showing an example of the organic electroluminescence display device 400 of the present invention. The organic electroluminescence display device 400 is laminated in contact with the organic electroluminescence display unit 40, the touch panel member 20, the adhesive layer 6, the polyimide film 1 of the present invention described above, and the first surface 11 of the polyimide film 1. The functional layers 2 are laminated in this order.
The touch panel member 20 included in the organic electroluminescence display device 400 has the same configuration as the touch panel member 20 shown in FIGS. 6 to 7. That is, in the organic electroluminescence display device 400, in the first laminated body 201 of the touch panel member 20, the first polyimide film 1a, which is the polyimide film of the present invention, and the first surface 11 of the first polyimide film 1a. The second polyimide film 1b, which is the polyimide film of the present invention, and the second polyimide film 1b in the second laminated body 202 of the touch panel member 20 have a functional layer 2a laminated in contact with the touch panel member 20. It has a functional layer 2b laminated in contact with the first surface 11 of the above.
Since the configuration of the organic electroluminescence display unit 40 is the same as that of the organic electroluminescence display unit 40 of the organic electroluminescence display device 300 described above, detailed description thereof will be omitted.

In FIGS. 10 to 11, the polyimide film of the present invention is arranged on the organic electroluminescence display unit 40 via the hard coat layer 3 and the second transparent electrode 5, or the hard coat layer 3b. However, the organic electroluminescence display device of the present invention may have a configuration in which the polyimide film of the present invention is arranged in contact with the organic electroluminescence display unit 40.

In the organic electroluminescence display device of the present invention, the polyimide film of the present invention contained in the organic electroluminescence display device exhibits excellent adhesion to the functional layer, has a good appearance, and has excellent optical characteristics. Therefore, it is suitable as a flexible display.
Further, when the organic electroluminescence display device of the present invention has a functional layer laminated in contact with the first surface of the polyimide film of the present invention contained in the organic electroluminescence display device, the polyimide film and the function thereof. It is suitable as a flexible display because it has excellent adhesion to the layer, has a good appearance, and has excellent optical characteristics.

[Evaluation methods]
<Surface swell>
Using a scanning white interference microscope, an image of interference fringes in a field of view of 700 μm × 700 μm was acquired on the surface of the object to be measured under the following measurement conditions.
[Measurement condition]
Surface waviness (Wa) measurement-Product name: VertScan (scanning white interference microscope), Hitachi High-Tech Science Co., Ltd.-Objective lens: 5x-CCD camera: Product name HR-50 1/3, Sony Corporation-Wavelength Filter: 530 White
-Field of view size (pixels): 640 x 480
-Measurement mode: wave
-Measurement range (z-axis direction): Start 10 μm, Stop -50 μm
-XY size: Approximately 941 μm × 706 μm

(Mean value of surface waviness (Wa1) in the first region Wa1 _ave )
Next, in the interference fringe image obtained for the field of view of 700 μm × 700 μm, the interference fringe image extends in the direction orthogonal to the longitudinal direction of the object to be measured, and the width in the longitudinal direction is larger than the length in the direction orthogonal to the longitudinal direction. The first region was arbitrarily extracted so as to be narrow.
Specifically, the start positions (pixels) are set to X1: 0 and Y1: 0 from the interference fringe image in the field of view of 700 μm × 700 μm in the interference fringe image (for example, see FIG. 2) acquired for the surface of the object to be measured. The size was specified (pixels) at X: 480 and Y: 20, and the first region was extracted.
Next, the original surface of the object to be measured is determined from the interference fringe image of the first region arbitrarily extracted, and the obtained original surface is subjected to surface filter (S-filter) treatment to obtain the basic surface. A contour curved surface (waviness curved surface) was obtained by performing a predetermined surface filtering treatment (cutoff value λ _c = 10 μm) on the basic surface.
Next, the contour curved surface (waviness curved surface) is represented by Z = f1 (x, y) with the average plane of a predetermined region defined for the contour curved surface (waviness curved surface) as the XY plane and the height direction as the Z axis. At that time, the value given by the above equation (1) expressed in nm units was calculated as the surface waviness (Wa1) of the first region.
Next, the position where the first region is extracted from the interference fringe image obtained for the field of 700 μm × 700 μm is moved from the previous extraction position in the longitudinal direction (Y-axis direction) of the measurement object in increments of 20 pixels. The surface waviness (Wa1) of the first region was calculated by repeating the same procedure as above for the interference fringe image of the extracted first region.
By repeating the above-mentioned calculation step of the surface waviness (Wa1) 24 times and calculating the average value of the surface waviness (Wa1) obtained in each, "the average value Wa1 of the surface waviness (Wa1) in the first region". " _Ave " was obtained.

(Mean value of surface waviness (Wa2) in the second region Wa2 _ave )
In the interference fringe image acquired in the calculation of the surface waviness (Wa1) of the first region described above, the width extending in the direction along the longitudinal direction of the object to be measured and perpendicular to the longitudinal direction is the longitudinal direction. A second region was arbitrarily extracted so that it was narrower than the length along the direction.
Specifically, the start positions (pixels) are set to X1: 0 and Y1: 0 from the interference fringe image in the field of view of 700 μm × 700 μm in the interference fringe image (for example, see FIG. 2) acquired for the surface of the object to be measured. The size was specified (pixels) at X: 20 and Y: 480, and the second region was extracted (see, for example, FIG. 3).
Next, the surface shape of the object to be measured is determined from the interference fringe image of the second region arbitrarily extracted, and the surface waviness (Wa1) of the first region is calculated from the cross-sectional curve of the obtained surface shape. The contour curve (waviness curve) is obtained by the same procedure as described, and the same procedure as described in the calculation of the surface waviness (Wa1) of the first region from the obtained contour curve (waviness curve). The surface swell (Wa2) of the second region was calculated.
Next, the position where the second region is extracted from the interference fringe image obtained for the field of 700 μm × 700 μm is moved from the previous extraction position in the lateral direction (X-axis direction) of the measurement object in 20pixels increments. The surface waviness (Wa2) of the second region was calculated by repeating the same procedure as above for the interference fringe image of the extracted second region.
By repeating the above-mentioned calculation step of the surface waviness (Wa2) 32 times and calculating the average value of the surface waviness (Wa2) obtained in each, "the average value Wa2 of the surface waviness (Wa2) in the second region". " _Ave " was obtained.

<Surface roughness>
Using a scanning white interference microscope, an image of interference fringes in a field of view of 95 μm × 71 μm was acquired on the surface of the object to be measured under the following measurement conditions.
[Measurement condition]
Surface roughness (Sa) measurement-Product name: VertScan (scanning white interference microscope), manufactured by Hitachi High-Tech Science Corporation
・ Objective lens: 50x
・ CCD camera: Product name HR-50 1/3, manufactured by Sony Corporation ・ Wavelength filter: 530 White
-Field of view size (pixels): 640 x 480
-Measurement mode: wave
-Measurement range (z-axis direction): Start 10 μm, Stop -50 μm
-XY size: Approximately 95 μm x 71 μm

Next, the original surface of the object to be measured was determined from the interference fringe image obtained for the field of view of 95 μm × 71 μm, and the obtained original surface was subjected to surface filter (S-filter) treatment to obtain the basic surface. The SL plane, which is a contour curved surface (roughness curved surface), was obtained by performing an L-filter treatment (cutoff value λ _c = 10 μm) on the basic surface.
Next, the XY plane is the average plane of a predetermined region defined for the SL plane (contour curved surface (roughness curved surface)), and the height direction is the Z axis, and the SL plane (contour curved surface (roughness curved surface)). )) Was expressed by Z = f2 (x, y), and the value given by the above equation (2) expressed in nm units was calculated as the surface roughness (Sa).

<Weight average molecular weight of polyimide precursor>
For the weight average molecular weight of the polyimide precursor, the polyimide precursor is prepared as a solution of N-methylpyrrolidone (NMP) having a concentration of 0.5% by weight, and the solution is filtered through a syringe filter (pore size: 0.45 μm) to develop the solution. As a solvent, a 10 mmol% LiBr-NMP solution having a water content of 500 ppm or less was used, and a GPC device (HLC-8120 manufactured by Tosoh Co., Ltd., detector: differential refractometer (RID) detector, column used: GPC LF-804 manufactured by SHODEX) was used. The measurement was carried out under the conditions of a sample injection amount of 50 μL, a solvent flow rate of 0.4 mL / min, a column temperature of 37 ° C., and a detector temperature of 37 ° C. using (connected in series). The weight average molecular weight of the polyimide is a polystyrene standard sample having the same concentration as the sample (weight average molecular weight: 364,700, 204,000, 103,500, 44,360,27,500, 13,030, 6,300, 3, It was used as a conversion value with respect to standard polystyrene measured based on 070). The elution time was compared with the calibration curve to determine the weight average molecular weight.

<Haze value>
It was measured by a haze meter (HM150 manufactured by Murakami Color Technology Research Institute) in accordance with JIS K-7105.

<Adhesion>
A cross-cut test based on JIS K 5600-5-6 was performed on the hard coat layer formed in [Preparation of laminated body] described later, and the peeling operation with tape was repeated 5 times, and then the coating film (hard coat layer) was performed. ) Was observed for peeling.
○: No peeling of the hard coat layer ×: There is peeling of the hard coat layer

<Appearance>
The laminate produced in [Preparation of the laminate] was placed in front of the light source, and the projected image projected on the screen was visually observed. Then, the projected image visually observed was compared with the appearance inspection film, and the appearance was evaluated according to the following evaluation criteria.
⊚: No streaks were found on the surface of the laminate ○: Some streaks were found on the surface of the laminate, but the level was almost inconspicuous visually. ×: Level that can be clearly confirmed visually on the surface of the laminate. The streaks were confirmed

(Synthesis Example 1)
In a 500 ml separable flask, 3081 g of dehydrated dimethylacetamide and 322 g (1.00 mol) of 2,2'-bis (trifluoromethyl) benzidine (TFMB) were placed, and the solution temperature of the solution in which TFMB was dissolved was increased. To the place controlled to 30 ° C, 443 g (1.00 mol) of 4,4'-(hexafluoroisopropyridene) diphthalic acid anhydride (6FDA) was gradually divided into several times so that the temperature rise was 2 ° C or less. A polyimide precursor solution 1 (solid content 20% by weight) in which the polyimide precursor 1 was dissolved was synthesized. The viscosity of the polyimide precursor solution 1 (solid content 20% by weight) at 25 ° C. was 34920 cps, and the weight average molecular weight of the polyimide precursor 1 measured by GPC was 408500.

(Example 1)
(Support polishing process)
A SUS foil (manufactured by Nissin Steel Co., Ltd.) having a thickness of 100 μm and a width of 500 mm was buffed according to the following procedure to polish the surface.
First, the SUS foil was fixed to the support base of the polishing machine by a vacuum chuck. Next, after applying a solid buff polishing agent (rod-shaped buff polishing agent) to the surface of the bias cotton buff, the bias cotton buff is placed on a wide polishing head, and the buff is rotated at high speed while reciprocating the polishing head. The surface was polished by contacting the surface of the SUS foil fixed to the support base. The surface polishing was performed by reciprocating the polishing head 12 times. As the solid buffing agent (rod-shaped buffing agent), a material containing calcined alumina was used as the polishing material.
For the SUS foil after polishing, the surface roughness (Sa) was measured, the average value of the surface waviness (Wa1) in the first region (Wa1) was calculated, and the average value Wa1 _ave of the second region was calculated by using the method described in the evaluation method. The average value Wa2 _ave of the surface waviness (Wa2) was calculated.
The surface roughness (Sa) of the SUS foil after polishing is 1.5 nm, the average value Wa1 _ave of the surface waviness (Wa1) in the first region is 4.3 nm, and the surface waviness in the second region (Wa1). The average value of Wa2), Wa2 _ave , was 3.4 nm.

(Preparation of polyimide film)
(1) The SUS foil whose surface has been polished in the polishing step of the support is used as a support, and the polyimide precursor solution 1 is applied on the surface roughness measurement surface of the SUS foil to apply the polyimide precursor solution 1. After forming the coating film of No. 1, it was dried in a circulation oven at 120 ° C. for 10 minutes.
(2) The temperature was raised to 350 ° C. at a heating rate of 10 ° C./min under a nitrogen stream (oxygen concentration of 100 ppm or less), held for 1 hour, and then cooled to room temperature.
(3) The polyimide film 1 was obtained by peeling from the SUS foil. The film thickness of the polyimide film 1 was 51 μm.

[Preparation of laminated body]
To a 40 wt% methyl isobutyl ketone solution of pentaerythritol triacrylate, 10 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (BASF, Irgacure 184) was added to 100 parts by weight of pentaerythritol triacrylate to make a hard product. A composition for forming a coat layer was prepared.
The polyimide film 1 obtained in Example 1 was cut into a size of 10 cm × 10 cm, and the composition for forming a hard coat layer was applied to the surface of the cut polyimide film 1 in contact with the SUS foil, and ultraviolet rays were emitted from nitrogen. A hard coat layer, which is a cured film having a thickness of 10 μm, was formed by irradiating and curing the film with an exposure amount of 200 mJ / cm ² under an air stream to prepare a laminated body 1. The thickness of the laminated body 1 was 61 μm.

(Example 2)
Buffing was performed in the same manner as in Example 1 except that the number of reciprocating movements of the polishing head was changed to eight.
The surface roughness (Sa) of the SUS foil after polishing is 4.2 nm, the average value of the surface waviness (Wa1) in the first region is 10.8 nm, and the average value of the surface waviness ( _Wa2 ) in the second region. Wa2 _ave was 5.2 nm. A polyimide film 2 was obtained in the same manner as in Example 1 except that the SUS foil was used as a support. The film thickness of the polyimide film 2 was 50 μm.
Next, the composition for forming the hard coat layer was applied to the surface of the polyimide film 2 on the side in contact with the SUS foil in the same manner as in Example 1, and cured in the same manner as in Example 1 to harden. A coat layer was formed to prepare a laminated body 2. The thickness of the laminated body 2 was 60 μm.

(Example 3)
Buffing was performed in the same manner as in Example 1 except that the number of reciprocating movements of the polishing head was changed to 4.
The surface roughness (Sa) of the SUS foil after polishing is 8.8 nm, the average value of the surface waviness (Wa1) in the first region is 38.1 nm, and the average value of the surface waviness ( _Wa2 ) in the second region. Wa2 _ave was 23.5 nm. A polyimide film 3 was obtained in the same manner as in Example 1 except that the SUS foil was used as a support. The film thickness of the polyimide film 3 was 50 μm.
Next, the composition for forming the hard coat layer was applied to the surface of the polyimide film 3 on the side in contact with the SUS foil in the same manner as in Example 1, and cured in the same manner as in Example 1 to harden. A coat layer was formed to prepare a laminated body 3. The thickness of the laminated body 3 was 60 μm.

(Comparative Example 1)
Buffing was performed in the same manner as in Example 1 except that the number of reciprocating movements of the polishing head was changed to 16.
The surface roughness (Sa) of the SUS foil after polishing is 0.9 nm, the average value of the surface waviness (Wa1) in the first region, Wa1 _ave is 4.2 nm, and the average value of the surface waviness (Wa2) in the second region. Wa2 _ave was 3.9 nm. A polyimide film 4 was obtained in the same manner as in Example 1 except that the SUS foil was used as a support. The film thickness of the polyimide film 4 was 50 μm.
Next, the composition for forming the hard coat layer was applied to the surface of the polyimide film 4 on the side in contact with the SUS foil in the same manner as in Example 1, and cured in the same manner as in Example 1 to harden. A coat layer was formed to prepare a laminated body 4. The thickness of the laminated body 4 was 60 μm.

(Comparative Example 2)
The number of reciprocating movements of the polishing head was changed to 6 times, and the solid buff polishing agent (rod-shaped buff polishing agent) was more than the polishing material blended in the solid buff polishing agent (rod-shaped buff polishing agent) used in Example 1. Buffing was performed in the same manner as in Example 1 except that a polishing material having a small particle size was used.
The surface roughness (Sa) of the SUS foil after polishing is 7.5 nm, the average value of the surface waviness (Wa1) in the first region is 42.7 nm, and the average value of the surface waviness ( _Wa2 ) in the second region. Wa2 _ave was 18.0 nm. A polyimide film 5 was obtained in the same manner as in Example 1 except that the SUS foil was used as a support. The film thickness of the polyimide film 5 was 51 μm.
Next, the composition for forming the hard coat layer was applied to the surface of the polyimide film 5 on the side in contact with the SUS foil in the same manner as in Example 1, and cured in the same manner as in Example 1 to harden. A coat layer was formed to prepare a laminated body 5. The thickness of the laminated body 5 was 61 μm.

(Comparative Example 3)
The number of reciprocating movements of the polishing head was changed to 3 times, and the solid buff polishing agent (rod-shaped buff polishing agent) was more than the polishing material blended in the solid buff polishing agent (rod-shaped buff polishing agent) used in Example 1. Buffing was performed in the same manner as in Example 1 except that a polishing material having a large particle size was used.
The surface roughness (Sa) of the SUS foil after polishing is 15.4 nm, the average value of the surface waviness (Wa1) in the first region is 113.7 nm, and the average value of the surface waviness ( _Wa2 ) in the second region. Wa2 _ave was 130.1 nm. A polyimide film 6 was obtained in the same manner as in Example 1 except that the SUS foil was used as a support. The film thickness of the polyimide film 6 was 50 μm.
Next, the composition for forming the hard coat layer was applied to the surface of the polyimide film 6 on the side in contact with the SUS foil in the same manner as in Example 1, and cured in the same manner as in Example 1 to harden. A coat layer was formed to prepare a laminated body 6. The thickness of the laminated body 6 was 60 μm.

With respect to the polyimide films 1 to 6 obtained in Examples 1 to 3 and Examples 1 to 3 before performing [Preparation of laminated body], the haze value and the contact surface with the SUS foil were determined by using the above evaluation method. The surface roughness (Sa) was measured, the average value Wa1 _ave of the surface waviness (Wa1) in the first region was calculated, and the average value Wa2 _ave of the surface waviness (Wa2) in the second region was calculated. The evaluation results are shown in Table 1.
Further, with respect to the laminates 1 to 6 obtained in Examples 1 to 3 and Examples 1 to 3, the adhesion, appearance and haze value were evaluated by using the above evaluation method. The evaluation results are shown in Table 1.

From Table 1, the difference between the average value Wa1 _ave of the surface undulation (Wa1) in the first region and the average value Wa2 _ave of the surface undulation (Wa2) in the second region in the field of view of 700 μm × 700 μm (Wa1 _ave -Wa2). The polyimide films of Examples 1 to 3 having a polyimide film having an _ave ) of 20 nm or less and a surface roughness (Sa) of the first surface of 1 nm or more and 10 nm or less in a field of view of 71 μm × 95 μm are polyimide. The contact surface of the film with the SUS foil and the functional layer have excellent adhesion, the generation of streaks is suppressed in the laminated body, the appearance is good, the haze value is low, and the optical characteristics are improved. It was excellent. ..
On the other hand, in the laminated body 4 of Comparative Example 1, since the surface roughness (Sa) of the polyimide film 4 was less than 1 nm, the adhesion to the hard coat layer was inferior, and the hard coat layer was partially peeled off. ..
Further, in the laminated body 5 of Comparative Example 2, the difference between the average value Wa1 _ave of the surface waviness (Wa1) in the first region and the average value Wa2 _ave of the surface waviness (Wa2) in the second region of the polyimide film 5. Since (Wa1 _ave -Wa2 _ave ) exceeded 20 nm, streaks were generated and the appearance was inferior.
Further, in the laminated body 6 of Comparative Example 3, since the surface roughness (Sa) of the polyimide film 6 exceeded 10 nm, the haze value was as high as 4.1%, it was translucent, and it was inferior in optical characteristics. there were.

1 Polyimide film 1a First polyimide film 1b Second polyimide film A1 First region extending in the direction orthogonal to the longitudinal direction A2 Second region extending in the direction along the longitudinal direction 11 First surface 12 Second surface 2, 2a, 2b Functional layer 3, 3a3b Hard coat layer 4 First transparent electrode 41 First conductive part 5 Second transparent electrode 51 Second conductive part 6 Adhesive layer 7 First take-out wire 71 First terminal 8 Second take-out wire 81 Second terminal 13 Edge edge of polyimide film 1 14 Active area 15 Inactive area 16 Connection part 10, 20 Touch panel member 201 First laminated body 202 Second laminated body 30 Liquid crystal display 40 Organic polyimide display 100, 200 Liquid crystal display 300, 400 Organic polyimide display

Claims (21)

A long polyimide film that is orthogonal to the longitudinal direction of the polyimide film in a 700 μm × 700 μm field of view in the first surface when one surface of the polyimide film is used as the first surface. The average of the surface waviness (Wa1) of the first region (A1) arbitrarily extracted so as to extend in the direction and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The value (Wa1 _ave ) and the width extending along the longitudinal direction of the polyimide film and perpendicular to the longitudinal direction were arbitrarily extracted so as to be narrower than the length in the longitudinal direction. The difference (Wa1 _ave -Wa2 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) is 20 nm or less, and in the field of view of 71 μm × 95 μm in the first plane. A polyimide film having a surface roughness (Sa) of 1 nm or more and 10 nm or less,
A laminated body having a functional layer laminated in contact with the first surface of the polyimide film. The laminate according to claim 1, wherein the functional layer is a hard coat layer. The laminate according to claim 2 , wherein the hard coat layer contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound. The radically polymerizable compound is a compound having two or more (meth) acryloyl groups in one molecule, and the cationically polymerizable compound is a compound having at least one of an epoxy group and an oxetanyl group in one molecule. The laminated body according to claim 3 . The laminate according to any one of claims 1 to 4, wherein the laminate has a haze value of 2.0 or less according to JIS K-7105. It is a polyimide film having a long shape and for forming a functional layer on the first surface when one surface is used as the first surface.
In the field of view of 700 μm × 700 μm in the first plane, the polyimide film extends in a direction orthogonal to the longitudinal direction, and the width in the longitudinal direction is narrower than the length in the direction orthogonal to the longitudinal direction. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (A1) arbitrarily extracted so as to extend in the direction along the longitudinal direction of the polyimide film and orthogonal to the longitudinal direction. The difference (Wa1 _ave ) from the average value (Wa2 _ave ) of the surface waviness (Wa2) of the second region (A2) arbitrarily extracted so that the width in the direction to be performed is narrower than the length in the longitudinal direction. Wa2 _ave ) is 20 nm or less, and the surface roughness (Sa) in the field of view of 71 μm × 95 μm in the first plane is 1 nm or more and 10 nm or less. The polyimide film according to claim 6, wherein the polyimide film has a haze value of 2.0 or less according to JIS K-7105. A surface material for a display, which is the polyimide film according to claim 6 or 7, or the laminate according to any one of claims 1 to 5. The display surface material according to claim 8, which is for a flexible display. The polyimide film according to claim 6 or 7, and the polyimide film.
A transparent electrode composed of a plurality of conductive parts arranged on one surface side of the polyimide film, and
A touch panel member comprising a plurality of take-out wires electrically connected on at least one side of the end of the conductive portion. The touch panel member according to claim 10, further comprising a functional layer laminated in contact with the first surface of the polyimide film. A liquid crystal display unit having a liquid crystal layer formed between the substrates arranged so as to face each other,
The liquid crystal display device comprising the polyimide film according to claim 6 or 7, which is arranged on one side of the liquid crystal display unit. The liquid crystal display device according to claim 12, which has a functional layer laminated in contact with the first surface of the polyimide film. An organic electroluminescence display unit having an organic electroluminescence layer formed between substrates arranged to face each other, and an organic electroluminescence display unit.
The organic electroluminescence display device comprising the polyimide film according to claim 6 or 7, which is arranged on one side of the organic electroluminescence display unit. The organic electroluminescence display device according to claim 14, further comprising a functional layer laminated in contact with the first surface of the polyimide film. By polishing the surface of the elongated support, the surface of the support extends in a direction orthogonal to the longitudinal direction of the support in a field of view of 700 μm × 700 μm, and the width in the longitudinal direction is increased. The average value (Wa1 _ave ) of the surface waviness (Wa1) of the first region (B1) arbitrarily extracted so as to be narrower than the length in the direction orthogonal to the longitudinal direction, and along the longitudinal direction of the support. The average of the surface waviness (Wa2) of the second region (B2) arbitrarily extracted so that the width extending in the direction and orthogonal to the longitudinal direction is narrower than the length in the longitudinal direction. The step of setting the difference (Wa1 _ave -Wa2 _ave ) from the value (Wa2 _ave ) to 20 nm or less and setting the surface roughness (Sa) of the surface of the support to 71 μm × 95 μm in a visual field of 1 nm or more and 10 nm or less. ,
A polyimide precursor composition containing a polyimide precursor and an organic solvent is applied to the surface of the support to form a coating film of the polyimide precursor composition, or a polyimide composition containing a polyimide and an organic solvent. To form a coating film of the polyimide composition by applying
The organic solvent is removed from the coating film of the polyimide precursor composition and the polyimide precursor contained in the coating film of the polyimide precursor composition is imidized, or the organic is said from the coating film of the polyimide composition. The process of forming a polyimide film by removing the solvent,
A method for producing a polyimide film. The method for producing a polyimide film according to claim 16, wherein the polyimide film has a haze value of 2.0 or less according to JIS K-7105. A step of preparing a polyimide film obtained by the method for producing a polyimide film according to claim 16 or 17.
A step of forming a coating film of the composition for forming a functional layer on the surface on the side in contact with the support of the polyimide film, and
A method for producing a laminate including the step of curing the coating film. The method for producing a laminate according to claim 18, wherein the composition for forming a functional layer is a composition for forming a hardcourt layer. The method for producing a laminate according to claim 19 , wherein the composition for forming a hard coat layer contains at least one of a radically polymerizable compound and a cationically polymerizable compound. A surface for a display, comprising a step of manufacturing a polyimide film by the manufacturing method according to claim 16 or 17, or a step of manufacturing a laminate by the manufacturing method according to any one of claims 18 to 20. Material manufacturing method.

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