TWI728996B - Polyimide substrate film with functional layer, manufacturing method thereof, and long polyimide laminate - Google Patents

Abstract

The present invention provides a polyimide substrate film with a functional layer that can prevent foreign matter from being mixed into a polyimide substrate film, has good peelability from a carrier film, and has a functional layer on the polyimide substrate film的制造方法。 Manufacturing method. A method for manufacturing a polyimide substrate film with a functional layer, wherein a first solution is applied to a continuously supplied conveying body to perform a first heat treatment, and then a second solution is applied to perform a second heat treatment, thereby obtaining A long polyimide laminate having a first polyimide hardened layer and a second polyimide hardened layer, and then one of the polyimide hardened layers is set as a polyimide substrate film, and the other One is set as a carrier film, a functional layer is formed on the polyimide substrate film, and the carrier film is separated, thereby obtaining a polyimide substrate film having a functional layer.

Description

Polyimide substrate film with functional layer, manufacturing method thereof, and long polyimide laminate

The present invention relates to a method for manufacturing a polyimide substrate film with a functional layer, and a long polyimide substrate film with a functional layer. In detail, it relates to a method for forming a liquid crystal display device or Organic EL lighting, electronic paper, touch screens, solar cells, color filters, etc., including flexible displays such as electroluminescence (EL) displays, which have functional layers and polyimide substrate films with functional layers Manufacturing method and long polyimide substrate film with functional layer. In addition, it relates to a long polyimide laminate and functional layer for obtaining such a long polyimide substrate film with functional layer The long polyimide laminate.

Display devices such as liquid crystal display devices and organic EL display devices can be used for various display applications ranging from large displays such as televisions to small displays such as mobile phones, personal computers, and smartphones. As a representative display device of the display device, there is an organic EL display device. For example, in this organic EL display device, a thin film transistor (hereinafter referred to as TFT (Thin Film Transistor)) is formed on a glass substrate as a supporting substrate. The electrodes, light-emitting layers, and electrodes are sequentially formed, and finally, another glass substrate or multilayer film is used for hermetic sealing and production.

Here, by replacing the glass substrate as the supporting base material with a resin substrate, thinness × light weight × flexibility can be achieved, and the use of the display device can be further expanded.

For example, Patent Document 1 relates to the invention of polyimide and its precursor useful as a plastic substrate for flexible displays, and reports the use of an alicyclic structure such as cyclohexylphenyltetracarboxylic acid. Polyimides formed by reacting tetracarboxylic acids with various diamines have excellent transparency. In addition, attempts are being made to use flexible resins as supporting substrates to achieve weight reduction. For example, the following Non-Patent Document 1 and Non-Patent Document 2 propose organic EL displays in which polyimide with high transparency is applied to the supporting substrate. Device.

In this way, it is known that resin substrates such as polyimide can be effectively used as flexible substrates for flexible displays. However, compared with glass, resin substrates are generally inferior in terms of dimensional stability, transparency, heat resistance, moisture resistance, and gas barrier properties. Therefore, they are currently in the research stage and various studies are underway.

For example, Non-Patent Document 3 proposes the following method: after a predetermined functional layer is formed on a resin substrate coated and fixed on glass, it is released by what is called a plastic electronic laser (Electronics on Pastic by Laser Rlease, EPLaR) The process method irradiates a laser from the glass side to forcibly separate the resin substrate with the functional layer from the glass.

In addition, Non-Patent Document 4 proposes the following method: a solution of polyamide acid (polyimide precursor) is applied to glass via a release layer, and then cured, and a predetermined polyimide substrate is provided on the obtained polyimide substrate. After the functional layer, the polyimide substrate was peeled from the glass. In the case of this method, the polyamide acid solution is applied to an area wider than the peeling layer, and the peripheral portion of the cured polyimide substrate is directly fixed to the glass in advance to leave the peripheral portion on the glass In this method, a cut is made in the part where the functional layer is formed, and the polyimide substrate formed via the peeling layer is separated from the glass.

The techniques disclosed in Non-Patent Document 3 and Non-Patent Document 4 both ensure the handleability and dimensional stability of the resin substrate by forming a resin substrate on glass and forming a functional layer on the resin substrate. However, in these methods, since a special method is used to separate the resin substrate from the glass, there are problems such as low productivity. That is, in the method using the EPLaR process described in Non-Patent Document 3, it not only takes time to separate the resin substrate from the glass, but also may adversely affect the surface properties of the resin substrate. In addition, in the method described in Non-Patent Document 4, in addition to the increase in the number of steps, an area that cannot be used as a resin substrate is generated, resulting in waste. Therefore, it is strongly desired to develop a technology that can effectively utilize the advantages of the resin substrate and can be used in a way that contributes to industry.

As a method for solving this problem, a polyimide laminate is disclosed, which is a polyimide laminate having a polyimide film on the back side of a polyimide substrate instead of glass, and is characterized by : The interface between the polyimide substrate and the polyimide film has specific performance. After a predetermined functional layer is formed on the surface of the polyimide substrate, the polyimide film can be separated (see Patent Document 2). The polyimide laminate is one that uses a polyimide film instead of the glass in the non-patent document 3 or non-patent document 4 as the supporting substrate, and the polyimide film is coated on the surface of the polyimide film. The acid solution is heated to form a polyimide substrate on the supporting substrate. Furthermore, according to the polyimide laminate obtained in the above manner, it is possible to ensure handleability, dimensional stability, etc., and in addition, since the polyimide substrate can be easily separated from the supporting base material, the polyimide can be formed The film can be suitably used for the manufacture of touch screens, display devices, and the like. [Prior Art Literature]

[Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2008-231327 [Patent Document 2] Japanese Patent Laid-Open No. 2014-61685

[Non-Patent Document] [Non-Patent Document 1] S. An et. al., "2.8-inch WQVGA flexible active matrix organic light emitting using high-performance low-temperature polysilicon TFT on a plastic substrate Diode (2.8-inch WQVGA Flexible AMOLED Using High Performance Low Temperature Polysilicon TFT on Plastic Substrates)", SID2010 Abstract (DIGEST), p706 (2010) [Non-Patent Document 2] Oishi et. al., "Transparent PI for flexible display", IDW 11 FLX2/FMC4-1 [Non-Patent Document 3] EI Haskal et. al. "Using EPLaR process Flexible OLED Displays Made with the EPLaR Process", Proc.Eurodisplay 07, pp.36-39 (2007) [Non-Patent Document 4] Li Zhengzhong (Cheng-Chung Lee et. al.) "A Novel Approach to Make Flexible Active Matrix Displays", SID10 Digest, pp.810-813 (2010)

[Problems to be Solved by the Invention] According to the method described in Patent Document 2, it is possible to ensure operability, dimensional stability, etc., and to easily separate the polyimide substrate from the supporting base material to form a polyimide film Therefore, it is believed that the application of resin substrates can be promoted to replace existing glass substrates. However, as described in the method described in Patent Document 2, a polyimide film is used as a support substrate, and a polyimide acid (polyimide precursor) solution or a polyimide resin solution is applied thereon, and When heat treatment is performed to obtain a polyimide substrate film, if foreign matter such as particles adheres to the polyimide film as a support base material, it may be directly mixed into the polyimide substrate film.

For example, in the manufacturing steps of flexible components such as liquid crystal display devices, organic EL displays, organic EL lighting, electronic paper, touch screens, solar cells, color filters, etc., a highly clean environment is required. Dust, etc., are also likely to cause a significant reduction in the characteristics of the flexible component due to its mixing. In addition, with the improvement in performance, miniaturization, and thinning of flexible components, it is required to make the polyimide substrate film itself thinner. However, if the polyimide substrate film becomes thinner, it may be damaged from the supporting substrate. The polyimide substrate film was damaged during the peeling process, and there is room for further improvement of the peelability.

Therefore, the inventors of the present invention have repeatedly studied the above-mentioned problems and found that the first solution and the second solution containing polyimine precursor or polyimine resin solution are used on the conveying body. These solutions are applied separately, and the first heat treatment and the second heat treatment are performed to obtain a long polyimide laminate in which a carrier film and a polyimide substrate film are laminated, thereby preventing the mixing of foreign matter as much as possible, and The carrier film and the polyimide substrate film have good peelability and can be suitably used for the manufacture of flexible elements, thus completing the present invention.

Therefore, the object of the present invention is to provide a polyimide substrate film with a functional layer that can prevent foreign matter from being mixed into a polyimide substrate film, has good peelability from the carrier film, and has a functional layer on the polyimide substrate film. A manufacturing method of an imide substrate film, and a polyimide substrate film with a functional layer obtained therefrom.

In addition, another object of the present invention is to provide a polyimide laminate for obtaining the polyimide substrate film with a functional layer, and a polyimide laminate with a functional layer. [Means to Solve the Problem]

That is, the gist of the present invention is as follows. (1) A method for producing a polyimide substrate film with a functional layer, characterized in that: a first solution containing a polyimide precursor or a polyimide resin solution is applied to a continuously supplied conveying body. In the first heat treatment, at least a tack-free surface is formed on the surface of the first solution, and then a second solution containing a polyimide precursor or a polyimide resin solution is applied to perform the second heat treatment, Thus, a long polyimide laminate is obtained, the long polyimide laminate is provided with a first polyimide hardened layer composed of a first solution and a second polyimide hardened layer composed of a second solution , And separated from the conveying body by taking the traveling direction of the conveying body as the longitudinal direction, and then separating the first polyimide hardened layer and the second polyimide hardened layer of the long polyimide laminate One is set as a polyimide substrate film, and the other is set as a carrier film. After forming a functional layer on the polyimide substrate film, the carrier film is separated to obtain a polyimide substrate film with a functional layer.

(2) The method for producing a polyimide substrate film with a functional layer as described in (1), wherein the long polyimide laminate is temporarily wound on a winding roller, and then the polyimide laminate is wound up. In the polyimide laminate, a functional layer is continuously formed on the polyimide substrate film, or while the polyimide laminate is rolled out, it is cut into sheets with a predetermined length, and is tailored to each sheet. The polyimide laminate forms a functional layer on the polyimide substrate film.

(3) The method for producing a polyimide substrate film with a functional layer as described in (1) or (2), wherein in the process of obtaining the long polyimide laminate, the conveying body is It is separated before the second heat treatment or after the second heat treatment.

(4) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (3), wherein the conveying body is a metal roller, an endless belt, or Long substrate rolled into a roll.

(5) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (4), wherein the carrier film includes a first cured polyimide layer, and The polyimide substrate film includes a second polyimide hardened layer.

(6) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (4), wherein the polyimide substrate film includes a first polyimide hardened film. Layer, the carrier film includes a second polyimide hardened layer.

(7) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (6), wherein the carrier is coated with a polyimide resin solution containing a first One solution is subjected to the first heat treatment with 60°C to 300°C as the maximum temperature, and a non-stick surface is formed on the surface of the first solution.

(8) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (6), wherein the carrier is coated with a polyimide precursor containing a polyimide precursor. One solution is subjected to the first heat treatment with 100°C to 450°C as the maximum temperature to form the first polyimide hardened layer composed of the first solution.

(9) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (8), wherein the maximum temperature of the heat treatment in the second heat treatment is 100° C. to 450 ℃.

(10) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (9), wherein the first polyimide hardened layer and the second polyimide The interlayer adhesion strength of the amine hardened layer is 1 N/m～20 N/m, and the thickness of the first polyimide hardened layer or the second polyimide hardened layer as the polyimide substrate film is 1 μm～ 50 μm.

(11) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (10), wherein the first polyimide substrate film as the polyimide substrate film The total light transmittance of the hardened layer or the second polyimide hardened layer is 80% or more.

(12) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (11), wherein the transport body includes a long base material rolled into a roll, and the long base The base material is a polyimide film, SUS foil, copper foil, or a composite body in which two or more of these are laminated.

(13) The method for producing a polyimide substrate film with a functional layer as described in any one of (1) to (12), wherein two or more of the polyimide-containing precursors or polyimide-containing precursors are used. The first solution of the imide resin solution is applied by overlaying these to form a first cured layer of polyimide.

(14) The method for producing a polyimide substrate film with a functional layer according to any one of (1) to (12), wherein two or more kinds of the polyimide-containing precursor or polyimide-containing precursor film are used. The second solution of the imide resin solution is applied by overlaying these to form a second cured layer of polyimide.

(15) A long polyimide laminate with a functional layer, characterized in that: relative to the long side direction of the long polyimide laminate on which a carrier film and a polyimide substrate film are laminated, the polyimide A functional layer is continuously formed on an amine substrate film, and the carrier film includes a polyimide obtained by curing one of a first solution or a second solution containing a polyimide precursor or a polyimide resin solution A hardened layer, the polyimide substrate film including a polyimide hardened layer formed by hardening the other of the first solution or the second solution containing a polyimide precursor or a polyimide resin solution, The thickness of the polyimide substrate film is 1 μm-50 μm, and the total light transmittance is more than 80%, and the interface with the carrier film has a surface roughness with arithmetic average roughness Ra of 0 nm-5 nm. The carrier film The interlayer adhesion strength with the polyimide substrate film is 1 N/m to 20 N/m.

(16) The long polyimide laminate with a functional layer according to (15), wherein the functional layer is an indium tin oxide (Indium Tin Oxide, ITO) film.

(17) The long polyimide laminate with a functional layer according to (15), wherein the functional layer is a TFT.

(18) The long polyimide laminate with a functional layer according to (15), wherein the functional layer includes a transparent conductive layer, a wiring layer, a conductive layer, a gas barrier layer, a thin film transistor, An electrode layer, a light-emitting layer, an adhesive layer, an adhesive layer, a transparent resin layer, a color filter resist, and a hard coat layer composed of any one or a combination of two or more layers.

(19) A long polyimide laminate, which is a long polyimide laminate in which a carrier film and a polyimide substrate film are laminated, the carrier film including a polyimide precursor or polyimide A cured polyimide layer formed by curing one of the first solution or the second solution of the imine resin solution, the polyimide substrate film including a polyimide precursor or a polyimide resin solution The polyimide hardened layer formed by curing the other of the first solution or the second solution, the long polyimide laminate is characterized in that the interlayer adhesion strength of the carrier film and the polyimide substrate film is 1 N/m-20 N/m, and the thickness of the polyimide substrate film is 1 μm-50 μm, and the total light transmittance is 80% or more.

(20) A long polyimide substrate film with a functional layer, characterized in that it includes a polyimide hardened layer formed by hardening a solution containing a polyimide precursor or a polyimide resin solution In the long side direction of the long polyimide substrate film, the functional layer is formed continuously. The thickness of the polyimide substrate film is 1 μm-50 μm, and the total light transmittance is more than 80%, which is the opposite of the functional layer. The surface on the side has a surface roughness with an arithmetic average roughness Ra of 0 nm to 5 nm. [Effects of the invention]

According to the present invention, a polyimide with a functional layer can be obtained that can prevent the mixing of foreign matter into the polyimide substrate film, has good peelability from the carrier film, and has a functional layer on the polyimide substrate film. Substrate film. Among them, the polyimide substrate film has excellent heat resistance and can be applied to the heat treatment process at high temperature, so it can be used for the manufacture of various flexible components using functional layers.

In addition, in the process of obtaining such a polyimide substrate film with a functional layer, in the present invention, after the long polyimide laminate is obtained, the polyimide constituting the polyimide laminate is Since the substrate film forms a functional layer, it can ensure handleability (handling), dimensional stability, and the like.

Hereinafter, the present invention will be described in detail. In the present invention, first, a first solution containing a polyimide precursor or a polyimide resin solution is applied to a continuously supplied conveying body to perform a first heat treatment, and at least a non-sticky surface is formed on the surface of the first solution. Then, a second solution containing a polyimide precursor or a polyimide resin solution is applied to perform a second heat treatment, thereby obtaining a long polyimide laminate, the long polyimide laminate It includes a first polyimide hardened layer made of the first solution and a second polyimide hardened layer made of the second solution, and is separated from the carrier with the traveling direction of the carrier as the longitudinal direction.

In the present invention, the use of a continuously supplied carrier is to use a first solution and a second solution containing a polyimide precursor or a polyimide resin solution, and to make the first polyimide resin solution by a so-called casting method. The amine hardening layer and the second polyimide hardening layer are laminated, in detail, in order to obtain a long polyimide laminate in which these polyimide hardening layers are laminated.

That is, the polyimide laminate is a long laminate film with a longer machine direction (MD) side relative to the transverse direction (TD) side, and the polyimide laminate is continuously supplied by It is obtained by coating the first solution on the transport body and performing the first heat treatment to form at least a non-sticky surface, and then coating the second solution thereon and performing the second heat treatment. In the case of such a long polyimide laminate, in the subsequent steps, a roll-to-roll process can be used to transport it. For example, the polyimide laminate may be rolled out after being temporarily wound on a winding roller. , The functional layer is formed continuously on one side. Therefore, for example, compared with the case where a sheet-shaped polyimide laminate is obtained by using a conveying body that is intermittently supplied, and the functional layer is formed by batch processing, the number of steps is reduced, so it is possible to eliminate as much foreign matter as possible. Possibility, in addition, it is also possible to efficiently manufacture flexible components using functional layers.

There are no particular limitations on the conveying body that is continuously supplied, and examples thereof include metal drums, endless belts, and long base materials wound in a roll shape. Among them, from the viewpoint of productivity, it is preferable to use an endless belt or a long substrate wound in a roll shape, and more preferable is a long substrate wound into a roll shape. Among them, in the case of a long substrate rolled into a roll, the longer the MD side is, the longer a long polyimide laminate can be obtained, which is ideal, but from the viewpoint of productivity and the like, it is preferable The (length on the MD side)/(length on the TD side) is preferably 50 or more, and more preferably 2000 or more. In addition, in the case of an endless belt, the longer the MD side, the better the productivity, but on the other hand, the device becomes expensive and the size or weight of the device increases. In terms of the balance of these, the length of the endless belt is preferably about 10 m to 50 m.

Here, as the material forming the conveying body, any material that can withstand at least the temperature of the first heat treatment in which the first solution is applied to form a non-sticky surface. Specifically, in the case of a long substrate rolled into a roll, it may be a polyimide film, SUS foil, copper foil, etc., which are excellent in flexibility in addition to strength and heat resistance, and may also be these Complex. Among them, preferred is a polyimide film. In addition, in the case of an endless belt, it is preferably made of SUS.

In addition, a first solution containing a polyimide precursor or a polyimide resin solution is applied to the continuously supplied conveying body to perform the first heat treatment, and at least a non-sticky non-sticky state is formed on the surface of the first solution. surface. Here, the term "non-sticky" refers to the state where the object does not adhere to the contact object when the object is in contact with the surface of the object. For example, when the first solution is applied and the first heat treatment is performed and then touched with a finger, The state where the constituent of the first solution does not adhere to the fingertips.

In addition, in order to make the first solution applied to the conveying body at least in a non-sticky state, the first heat treatment is used to dry the applied first solution so as to volatilize at least a part of the solvent. At this time, if the first solution is a polyimide resin solution, at least a part of it can also be imidized. If this first heat treatment is insufficient, it will not form a non-sticky surface and mix with the second solution, and there may be swelling in the polyimide laminate, or it may become impossible to separate the polyimide substrate. Membrane and carrier membrane. In addition, depending on the situation, it may become impossible to separate the transport body later.

Regarding the first heat treatment, it differs according to the type of the first solution used, but when the first solution contains the polyimide resin solution, since there is no need to perform the imidization reaction, it is sufficient to volatilize the solvent. Therefore, it is preferable to perform the first heat treatment with a maximum temperature of 60°C to 300°C, more preferably 150°C to 250°C, and to form a non-stick surface on the surface of the first solution applied to the conveying body. At this time, it is preferable that the solid content concentration of the first solution that becomes non-sticky by drying in the first heat treatment is about 95% to 99.5% by mass, and more preferably 99% to 99.5% by mass. should.

On the other hand, when the first solution contains a polyimide precursor, it is preferable to imidize at least the surface thereof. From this point of view, it is also possible to perform the first heat treatment with the highest temperature of preferably 100°C to 450°C, more preferably 180°C to 360°C, to form the first polyimide composed of the first solution. Hardened layer. At this time, it is preferable to "substantially complete imidization" of the polyimide precursor to form the first polyimide hardened layer. Here, the "almost complete imidization" refers to a state where the imidization rate is 90% or more. In this case, it is necessary to perform the heat treatment at a temperature higher than the temperature at which the non-stick state is formed by drying. By performing almost complete imidization, the polyimide substrate film and the carrier film become easier to separate. In this case, it is preferable that 300°C to 360°C be the maximum temperature. In addition, to the first solution containing the polyimide precursor, so-called "imination catalysts" such as pyridine, acetic anhydride, and N-methylimidazole may be added to perform imidization. By adding an imidation catalyst, imidization can easily proceed even at a relatively low temperature.

When "almost complete imidization" is performed, the solid content concentration of the first solution becomes approximately 100% by mass. However, if the heat treatment is carried out quickly, the solvent will volatilize rapidly from the first solution, which may cause problems such as foaming of the first solution applied to the conveying body. Therefore, in the first heat treatment, it is desirable to gradually increase the temperature from a relatively low temperature before reaching the maximum temperature. In this case, preferably, a method using a continuous heat treatment device that includes a plurality of furnaces and is set so that the temperature is gradually increased from the furnace on the inlet side of the sample to the furnace on the outlet side of the sample. As other methods, the following methods can be preferably cited: after drying (pre-heat treatment) with a heat treatment device at a maximum heat treatment temperature of 90°C to 180°C, heat treatment is performed within the stated maximum temperature range by another heat treatment device. (Post heat treatment). In the latter case, regarding the post-heat treatment temperature, the heat treatment is performed at a temperature higher than the pre-heat treatment temperature.

In addition, when applying the first solution on the conveying body, a well-known coating method can be used. Specifically, a knife coater, a die coater, a lip coater, etc. can be mentioned, and the lip coater is preferred because it is a hermetic type and the applicable viscosity range is wide.

After forming at least a non-stick surface on the surface of the first solution applied on the carrier as described above, the second solution containing the polyimide precursor or the polyimide resin solution is applied to perform the second The heat treatment forms a first polyimide hardened layer composed of the first solution and a second polyimide hardened layer composed of the second solution. In this second heat treatment, the solvent of the applied second solution may be dried to temporarily form a non-sticky state, and then the first cured layer of polyimide and the second cured layer of polyimide (when When the first polyimide hardened layer is formed in the first heat treatment, the second polyimide hardened layer is formed in the second heat treatment). After temporarily forming into a non-sticky state in this way, the second polyimide hardened layer (or the first polyimide hardened layer and the second polyimide hardened layer) is formed, which can further improve the hardening of these polyimide The peelability of the interface of the layer.

Regarding this second heat treatment, the heat treatment conditions for forming the second solution into a non-sticky state are the same as the heat treatment conditions for forming the first solution into a non-sticky state in the previous first heat treatment. In addition, after forming the second polyimide hardened layer (or the first polyimide hardened layer and the second polyimide hardened layer), when the second solution contains a polyimide precursor, the The heat treatment conditions for "almost complete imidization" described in the previous first heat treatment are the same, and it is preferable that the maximum temperature of the heat treatment in the second heat treatment be 100°C to 450°C. It is more preferably from 180°C to 360°C, and even more preferably from 300°C to 360°C. On the other hand, when the second solution contains a polyimide resin solution, it is preferable that the maximum temperature of the heat treatment is 150°C to 250°C.

Through such a second heat treatment, a long polyimide laminate can be obtained. The long polyimide laminate is provided with a first polyimide hardened layer and a second polyimide hardened layer, and the transport body The traveling direction is the longitudinal direction and is separated from the conveying body. Here, in the process of obtaining the long polyimide laminate, the conveying body may be separated before the second heat treatment, or may be separated after the second heat treatment. Figs. 1 to 3 schematically show the state until the long polyimide laminate is obtained. Fig. 1 is an example of a case where a long substrate 2 wound in a roll shape is used as a conveying body. Here, a second solution applied using a second Mono pump 6 is applied by a lip coater (not shown in the figure). After the second heat treatment is performed by the second heat treatment device 7, the long base material 2 is separated. In addition, FIG. 2 is an example of the case where the endless belt 11 is used as the conveying body, and FIG. 3 is an example of the case where the metal drum 12 is used as the conveying body, and both are coated by a lip coater (not shown in the figure). After the first solution applied by the Mono pump 4 is subjected to the first heat treatment by the first heat treatment device 5, the conveying body (the endless belt 11 and the metal drum 12) is separated. In order to separate the conveying body before the second heat treatment, it is desirable to form the first polyimide hardened layer by the first heat treatment in advance, including the case where the conveying body is separated after the second heat treatment, the conveying body and the first The adhesion strength between the polyimide hardened layers is preferably 1 N/m to 100 N/m, preferably 10 N/m to 50 N/m. In addition, the first heat treatment refers to the heat treatment performed by applying the first solution, and the second heat treatment refers to the heat treatment performed after the second solution is applied, and these may include a plurality of heat treatments, respectively. In addition, the arrow in the figure indicates the traveling direction of the conveying body and the like.

As a preferred form in the process of obtaining the long polyimide laminate, as shown in Figure 1, the use includes a roll-out roll (roll-out part) 1, a lip coater (not shown in the figure), a continuous drying furnace and a continuous furnace. The heat treatment device (the first heat treatment device 5, the second heat treatment device 7), and the winding roller (winding part) 9 for the conveying body and the polyimide laminate, and the winding roller (winding part) 10 A roll-to-roll (Roll To Roll, RTR) coating drying and curing device is sufficient. That is, the long base material 2 wound in a roll shape is mounted on the unwinding roll (unwinding part) 1, and while being unrolled, it is applied by a lip coater. The mono pump 4 and the mono pump 6 are applied. The first solution and the second solution are heat-treated to form a polyimide laminate 8 on the long substrate 2 respectively. Then, the long base material 2-polyimide laminate 8 is separated, and the long base material 2 and the polyimide layer are separated by each winding roller (winding part) 9 and winding roller (winding part) 10 The imine laminate 8 is wound into a roll shape. In addition, the so-called continuous drying furnace is one that connects two or more multiple drying furnaces, and the temperature of each drying furnace can be adjusted individually. Preferably, the setting temperature of the drying furnace is set to increase stepwise from the furnace on the unwinding section side to the furnace on the winding section side. For example, set the furnace on the unwinding section to 130°C, set the furnace on the winding section to 400°C, and set the furnace on the unwinding section and the furnace on the winding section to any of 130°C to 400°C. temperature. In addition, the so-called continuous furnace refers to those in which two or more furnaces are connected, and the temperature of each furnace can be adjusted individually. The set temperature of the preferable furnace is preferably set so as to increase stepwise from the furnace on the unwinding section side to the furnace on the winding section side. For example, set the furnace on the unwinding section to 130°C, set the furnace on the winding section to 400°C, and set the furnace on the unwinding section and the furnace on the winding section to any of 130°C to 400°C. temperature.

In addition, after the polyimide laminate is formed on the carrier, it is peeled between the carrier and the polyimide laminate in the coating, drying and curing device, and the long base is formed in the winding part for the long substrate. The material is wound into a roll shape, and the polyimide layered body is wound into a roll shape in the winding section for the polyimide laminated body. According to this method, the work efficiency in the subsequent steps of transporting the wound polyimide laminate to form a functional layer can be improved. In addition, the work efficiency when disposing or reusing the wound carrier is also good. Alternatively, after forming the polyimide laminate on the long base material, the long base material and the polyimide laminate in the state where these are laminated may be temporarily wound into a roll shape by another winding section. These are unrolled using an RTR-based peeling device equipped with an unwinding part and a winding part for the long base material and the polyimide laminate, and peeled between the long base material and the polyimide laminate. In the winding section for the long substrate, the long substrate is wound into a roll shape, and in the winding section for the polyimide laminate, the polyimide laminate is wound into a roll.

Regarding the polyimide laminate obtained as described above, one of the first polyimide hardened layer and the second polyimide hardened layer is set as a polyimide substrate film, and the other One is set as a carrier film. In a subsequent step, a functional layer is formed on the polyimide substrate film, and the carrier film is separated to form a polyimide substrate film with a functional layer. That is, the carrier film may include the first polyimide cured layer and the polyimide substrate film may include the second polyimide cured layer, or it may be formed such that the polyimide substrate film includes the first polyimide. The hardened layer and the carrier film include a second polyimide hardened layer. From the viewpoint that the surface smoothness of the polyimide substrate film is not affected by the surface smoothness of the conveying body, the former case is preferred (the carrier film is the first polyimide cured layer, polyimide The substrate film is preferably the second polyimide hardened layer).

In terms of maintaining strength as a polyimide substrate and making thin flexible components possible, the thickness of the polyimide substrate film is preferably 1 μm to 50 μm, preferably 1 μm to 20 μm, and more preferably The best value is 1 μm～15 μm. If the thickness of the polyimide substrate film exceeds 50 μm, the purpose may be deviated from the purpose when a thin flexible element is produced. On the contrary, if the thickness is less than 1 μm, the strength of the flexible element may become weak. Full inclination. In addition, the thickness of the carrier film is preferably 30 μm to 200 μm from the viewpoint of ensuring processability when forming a functional layer. If the thickness exceeds 200 μm, winding tends to become difficult. On the contrary, if the thickness is less than 30 μm, processing may become difficult. What is necessary is just to adjust the 1st solution and 2nd solution applied so that it may become these thicknesses.

In addition, regarding the interlayer adhesion strength between the carrier film and the polyimide substrate film, as long as these layers do not peel off when the functional layer is formed, and when the carrier film is separated after the functional layer is formed, peeling can be performed between these layers. It is preferable that the adhesion strength between these layers is 1 N/m to 20 N/m, and more preferably 1.5 N/m to 15 N/m.

In the present invention, after the first solution for forming the carrier film is applied to the carrier to form at least a non-sticky surface, the second solution for forming the polyimide substrate film may be applied twice or more. , To form a polyimide substrate film with multiple polyimide layers. At this time, each time the second solution is applied, the second heat treatment may be divided into multiple times by performing heat treatment at 60°C to 300°C, and finally these amides may be formed, or the second solution may be applied separately. In order to carry out multiple times, heat treatment at 60°C to 300°C to form the coated surface into a non-stick state, and finally to be imidized. In the former case, the polyimide substrate film can be separated by each polyimide layer individually, and in the latter case, a polyimide layer having multiple polyimide layers with different characteristics can be formed. Imine substrate film.

In addition, when the first solution for forming the carrier film is applied to the carrier, the first solution may be applied twice or more to form a carrier film having a plurality of polyimide layers. In this case, the first heat treatment may be performed every time the first solution is applied to achieve a non-stick state, or the application of the first solution may be divided into multiple times, and the first heat treatment may be performed as a whole to achieve a non-stick state. The surface forms a non-stick surface. In the former case, it is easy to provide the respective characteristics of the plurality of polyimide layers individually for each layer, and in the latter case, it is easy to provide the respective characteristics to each layer integrally. In addition, the production efficiency is also high.

In addition, in the case of using the polyimide substrate film with a functional layer of the present invention to manufacture a bottom emission type flexible element like an organic EL display device, it is based on Japanese Industrial Standards (JIS) J 7375: 2008 The total light transmittance specified in the above is preferably 80% or more, preferably 85% or more. Similarly, when the flexible element is a touch screen, it is preferable that the total light transmittance of the 20 μm-thick polyimide substrate film is 90% in consideration of the visibility of the display. The above is appropriate.

In addition, the difference between the coefficient of thermal expansion (CTE) of the polyimide substrate film and the CTE of the carrier film (DCTE) is preferably -25 ppm/K to 25 ppm/K, more preferably It is -10 ppm/K～10 ppm/K. If the difference in CTE is within these ranges, in the process of obtaining the polyimide laminate, the interlayer peeling or warping between the conveying body and the polyimide laminate can be appropriately suppressed, and in addition, the functional layer is formed When it is on a polyimide substrate film, interlayer peeling or warping can be suitably suppressed.

In addition, with regard to the surface of the polyimide substrate film forming the interface with the carrier film, the arithmetic average roughness (Ra) is preferably 0 nm to 5 nm, and more preferably 0.3 nm to 3 nm, More preferably, it is 0.3 nm to 2 nm. In the present invention, since the first polyimide hardened layer and the second polyimide hardened layer constituting the carrier film and the polyimide substrate film can be formed by the casting method, it is possible to ensure the interface between these layers. Flatness. Moreover, if the surface roughness of the polyimide substrate film forming the interface with the carrier film is within these ranges, there will be no peeling of the polyimide substrate film when the polyimide laminate is obtained or the functional layer is formed. In addition, the possibility of damage to the polyimide substrate film or the functional layer can be reliably eliminated when the carrier film is separated.

Similarly, regarding the surface of the carrier film forming the interface with the polyimide substrate film, it is also preferable that the arithmetic average roughness (Ra) is 0 nm to 5 nm, and more preferably 0.3 nm to 3 nm. nm, more preferably 0.3 nm to 2 nm. In addition, with regard to the surface of the carrier on which the first solution is applied, it is preferable that the arithmetic average roughness (Ra) is 0 nm to 3.5 nm, more preferably 0.3 nm to 3 nm, and still more preferably 0.3 nm～2 nm is appropriate. If the surface roughness of the transport body coated with the first solution falls within these ranges, unexpected peeling during the process of obtaining the polyimide laminate or when the transport body is separated from the polyimide laminate can be reliably eliminated. Possibility of causing damage. In addition, the arithmetic average roughness (Ra) is calculated based on the measurement value measured using an atomic force microscope (Atomic Force Microscope, AFM) under the conditions specified in JIS B0601:2013.

In the present invention, the polyimide forming the carrier film is not particularly limited. From the viewpoint of being inexpensive and easily available, it is preferable to use pyromellitic dianhydride (PMDA) as the acid anhydride compound. , 2,3,2',3'-biphenyltetracarboxylic dianhydride (2,2',3,3'-biphenyltetracarboxylic dianhydride, BPDA), or 3,3',4,4'-benzophenone Any one or more of tetracarboxylic dianhydride (3,3',4,4'-benzophenone tetracarboxylic dianhydride, BTDA), 4,4'-diaminodiphenyl ether (4,4'- diaminodiphenyl ether, 4,4'-DAPE), 2,2'-dimethyl-4,4'-diaminobiphenyl (2,2'-dimethyl-4,4'-diaminobiphenyl, m-TB), Or any one or more of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (2,2-bis[4-(4-aminophenoxy)phenyl]propane, BAPP) and reacted The polyimide is suitable. Among them, it is preferable that the acid anhydride compound is PMDA, and the diamine compound is 4,4'-DAPE.

In the present invention, the carrier film functions as a susceptor when the functional layer is formed on the polyimide substrate film side, and even in some cases, the operability or dimensional stability of the polyimide substrate film is ensured during the production process of the functional layer. It can also be removed after manufacturing the flexible element. Therefore, it does not matter even if it is assumed to be a person with poor transparency. By using the polyimide laminate like the present invention, a predetermined functional layer can be accurately and reliably formed on the polyimide substrate film, and a flexible element that is thinner, lighter, and more flexible can be obtained. . That is, the separation and removal of the carrier film can be carried out immediately after the formation of the functional layer through various process treatments, or it can be integrated with the polyimide substrate film for a certain period of time before being attached to other device components. Separate and remove after combining. In addition, as the member for an element, glass, a plastic plate, a film, a circuit board, and a frame can be mentioned, for example.

On the other hand, regarding the polyimide forming the polyimide substrate film, considering the heat resistance or transparency of the polyimide substrate film provided with the functional layer, it is preferable to use it as an acid anhydride compound. '-Oxydiphthalic anhydride (4,4'-oxydiphthalic anhydride, ODPA), pyromellitic dianhydride (PMDA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (1 ,2,3,4-cyclobutanetetracarboxylic dianhydride, CBDA), 1,2,3,4-cyclohexanetetracarboxylic dianhydride (1,2,3,4-cyclohexanetetracarboxylic dianhydride, CHDA), or 2,2-bis Any one or more of (3,4-anhydrodicarboxyphenyl)hexafluoropropane (2,2-bis(3,4-anhydrodicarboxyphenyl)hexafluoropropane, 6FDA), 4,4'-diamino- is used as the diamine compound 2,2'-bis(trifluoromethyl)biphenyl (4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, TFMB), 2,2'-dimethyl-4,4'- Diaminobiphenyl (m-TB) or 4,4'-(hexafluoroisopropylidene)dianiline (4,4'-(hexafluoroisopropylidene)dianiline, 4,46F) and any one or more of them are reacted Of polyimide. Among them, it is preferable that the acid anhydride compound is any one or more of 6FDA, PMDA, or CBDA, and the diamine compound is any one or more of TFMB or 4,46F.

In addition, as the solvent of the polyimide precursor or polyimide resin solution constituting the first solution and the second solution, for example, N-methylpyrrolidone (NMP), dimethylformaldehyde Dimethylformamide (DMF), dimethyl acetamide (DMAc), dimethyl sulfoxide (DMSO), dimethyl sulfate, cyclobutyrolactone, butyrolactone, cresol, phenol , Halogenated phenol, cyclohexanone, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether series, triethylene glycol dimethyl ether series, carbonate series (dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate) Base ester, ethylene carbonate, propylene carbonate, etc.).

In addition, the polyimide precursor solution or the polyimide solution may also contain a mold release agent if necessary. In addition, additives such as catalysts, antioxidants, heat stabilizers, antistatic agents, flame retardants, ultraviolet absorbers, and lubricants may also be included.

As the functional layer formed on the polyimide substrate film, well-known elements that ensure the function of a flexible element can be applied, such as organic EL×TFT, photoelectric conversion element, electronic paper drive element, color filter, touch Controlled screen, photoelectric conversion device, etc. As an example, in the case of manufacturing an organic EL display as a flexible element, as a functional layer, a TFT for image driving can be cited. The material of TFT is silicon semiconductor or oxide semiconductor. In the case of a conventional technology that does not use a flexible substrate, a barrier layer of an inorganic component is provided on a rigid support such as plate glass, and a TFT is formed thereon. High temperature treatment (about 300°C to about 400°C) is required for this formation, but if it is polyimide, it can withstand this high temperature treatment. In addition, in the case of manufacturing a touch screen as a flexible element, as the functional layer, an electrode layer such as a transparent conductive film and a metal mesh can be cited. As an example of a transparent conductive film, ITO (tin-doped indium oxide), SnO, ZnO, and indium-zinc oxide (Indium-Zinc Oxide, IZO) can be mentioned. When forming these electrode layers, by performing heat treatment at 200°C or higher, a conductive layer with a small resistance value can be formed, but if it is polyimide, it can withstand the high temperature treatment. Furthermore, it is not limited to a touch screen, and when a transparent conductive film is used as a functional layer, it is also called a "transparent conductive layer."

As a preferred form when the functional layer is formed on the polyimide substrate film of the polyimide laminate, as described above, the long polyimide laminate is temporarily wound on the winding roll and then rolled up. It is preferable to form the polyimide laminate while continuously forming a functional layer on the polyimide substrate film. In addition, the wound polyimide laminate can also be cut into sheets with a predetermined length while unwinding the wound polyimide laminate, and the polyimide laminate can be formed on the polyimide substrate film for each sheet of polyimide laminate. Functional layer.

After the functional layer is formed on the polyimide substrate film, the carrier film of the polyimide laminate is separated to obtain a polyimide substrate film having a functional layer. Here, as a method of separating the carrier membrane, there is no particular limitation, and a well-known method can be used. At this time, the carrier film may be peeled off by mechanical means such as a pinching starting tool such as pliers for forming the peeling starting point, a suction plate, and air blowing of the peeling part formed close to the peeling starting point. For example, use pliers to pinch the end of the carrier film to peel off the carrier film, and use other tools (pliers, rods, blades, sheets, etc.) to make a polyimide substrate film with a functional layer using the peeled portion as a starting point. Completely separated. Alternatively, needle-shaped, claw-shaped, insect-foot-shaped tools can be used instead of the pliers, and these tools can be inserted into the interface of the carrier film-polyimide substrate film with a functional layer to peel off the end of the carrier film, or The polyimide substrate film with the functional layer is sucked by the suction plate to peel off the carrier film. The method of using the suction plate in this way can be said to be a preferable method in terms of being able to hold the polyimide substrate film with a functional layer at the same time as peeling and stably holding it. The suction plate may be flat, or may be formed in a curved shape such as a semicircle. Furthermore, after peeling the end part of the carrier film by any of the above-mentioned methods, you may peel the carrier film using a suction plate or blowing compressed air.

Here, the case of manufacturing a touch screen using the long polyimide laminate of the present invention will be described as an example. In this example, a continuous manufacturing apparatus of the RTR method as shown in FIG. 4 is used. The continuous manufacturing apparatus is provided with: unwinding rolls (unwinding parts) for unwinding the long polyimide laminate 8 wound in a roll shape. ) 13. Conveying roller (guide roller) 14, process processing section 15, and winding roller (winding section) 17. Regarding the polyimide laminate 8 unwound from the unwinding roller 13, it passes through the transport roller 14 to prevent wrinkles or winding deviation. In the process processing section 15, the polyimide laminate 8 The surface of the imine substrate film side was vapor-deposited with ITO as a functional layer at 100° C. to 400° C. to form a functional layer (ITO) on the polyimide laminate. After that, the polyimide laminate 16 with a functional layer is wound into a roll shape by the winding roller 17 after passing through the conveying roller 14.

It is also possible to provide ITO on a resin film support such as polyethylene terephthalate, polyethylene, etc., instead of vapor-depositing ITO through the process processing section 15, and make the ITO surface closely adhere to the polyimide laminate in the polyimide laminate. After the surface of the imide substrate film, the resin film support is peeled off to form ITO on the polyimide laminate.

Next, while unwinding the polyimide laminate 16 with a functional layer wound in a roll shape, it cut into a sheet shape to a predetermined length. The size of the film can be arbitrarily determined according to the size of the manufactured touch screen. The ITO in the cut sheet-shaped polyimide laminate with a functional layer is processed into the shape of a circuit used as a touch screen by etching. A well-known method can be used for etching. For example, a liquid or film-like photoresist (which may be negative or positive) is laminated on the surface of ITO. In the case of a liquid photoresist, it is also possible to volatilize and dry the solvent by performing a heat treatment after lamination. Furthermore, a well-known photomask patterned into a circuit shape is laminated on the photoresist, exposed with a well-known exposure machine, and developed with a well-known developer. The developer can be appropriately selected from alkaline aqueous solutions, organic solvents, and the like according to the photoresist used. By development, a photoresist that matches the shape of the circuit used as a touch screen remains on the surface of the ITO. Then, it is brought into contact with an etching solution to remove ITO in the portion where the photoresist is not laminated. As the etching liquid, a well-known etching liquid can be used, and examples thereof include iron chloride-based or copper chloride-based etching solutions. Then, the remaining photoresist is peeled off and washed with water. Furthermore, the carrier film is peeled off using pliers or the like to obtain a polyimide substrate film with ITO used as a touch screen.

In addition, in the process processing section 15 of the continuous manufacturing apparatus shown in FIG. 4, ITO may be formed on the polyimide laminate, and then processed into the shape of a circuit used as a touch screen by etching, and then The polyimide laminate with a functional layer is wound by the winding roller 17, and then, as described above, it is cut into sheets of any size according to the size of the manufactured touch screen, and then peeled off. The carrier film is thus obtained as a polyimide substrate film with ITO used as a touch screen.

In addition, as another form of using the long polyimide laminate of the present invention to produce a touch screen, it is also possible to laminate silver or copper nanowires (hereinafter referred to as "nanowires") using a well-known ultraviolet light-curing adhesive. Line”) instead of ITO to form a functional layer. In this case, in the process processing section 15 of the continuous manufacturing apparatus of the RTR method, the surface of the polyimide laminate on the polyimide substrate film side is coated with an ultraviolet curable resin and dried to remove the The rice noodles are layered into the shape of a circuit. When laminating, a groove may be provided in the shape of the circuit, and a nanowire may be provided in the groove. Then, ultraviolet light is irradiated to harden the ultraviolet-curable adhesive, the nanowire is bonded to the polyimide laminate, and the polyimide laminate 16 with a functional layer is wound by the winding roller 17 into a roll shape. Then, while unwinding the polyimide laminate 16 with a functional layer, it was cut into a sheet with an arbitrary length in the same manner as in the previous production example, and the carrier film was peeled off to obtain a touch screen. Polyimide substrate film with nanowires used. At this time, the end surface of the nanowire can also be smoothed by polishing or the like.

In addition, in the present invention, the long polyimide laminate may be cut into pieces in advance according to the size of the flexible element such as a touch screen to be manufactured, and the sheet-shaped polyimide laminate may be After ITO is formed, it is processed into the shape of a circuit used as a touch screen by etching, and then the carrier film is peeled off to obtain a polyimide substrate film with ITO used as a touch screen or the like.

On the other hand, when the case where a cover film is manufactured using the long polyimide laminate of the present invention is used as an example for description, it is as follows. As in the case of manufacturing touch screens, using the continuous manufacturing apparatus of the RTR method as shown in FIG. 4, the polyimide laminate 8 unrolled from the unwinding roller 13 passes through the conveying roller 14 and is in the process processing section 15 In this, an adhesive layer is formed as a functional layer on the surface of the polyimide laminate on the side of the polyimide substrate film. As a method of forming the adhesive layer, a coating device such as a lip coater is used to apply well-known resin materials such as epoxy resin, acrylic resin, polyimide resin, and silicone resin, or solvent-based adhesives, which are the raw material of the adhesive layer. , Latex-based adhesives, hot-melt adhesives, rubber-based adhesives and other well-known adhesives (pressure-sensitive adhesives), and dried. Then, the polyimide laminate with the adhesive layer is wound into a roll shape by the winding roll 17, and it is cut into sheets of any size according to the size of the cover film produced, and the carrier film is peeled off to obtain Polyimide substrate film with adhesive layer used as cover film. In addition, when the adhesive layer is formed using the adhesive, the adhesive layer may also be referred to as an "adhesive layer". In the case of using the adhesive layer as the functional layer of the present invention, in the case of manufacturing the touch screen, ITO may be formed on the polyimide laminate, and then a cover layer may be laminated thereon When used to make the covering layer adhere.

In the present invention, in the process of obtaining a polyimide substrate film with a functional layer like the polyimide substrate film provided with an adhesive layer, it may also be used separately in the continuous manufacturing apparatus of the RTR method as described above. A winding roll for winding the carrier film is provided to wind a long polyimide substrate film with a functional layer. That is, in the process processing section, after the functional layer is formed on the polyimide laminate, the carrier film is peeled off in the continuous manufacturing device of the RTR method, and the carrier film is wound with a winding roller (not shown in the figure). In addition, the polyimide substrate film with the functional layer is wound by the winding roller 17. The wound polyimide substrate film with a functional layer can also be used after being cut into sheets according to the size of the flexible element as needed.

Furthermore, in the case of manufacturing an organic EL display using the long polyimide laminate of the present invention, for example, the polyimide laminate is cut into a sheet according to the size of the organic EL display to be manufactured in advance, and the sheet A glass sheet is laminated on the surface on the carrier film side of the shaped polyimide laminate. Then, on the surface of the polyimide substrate film side, TFT, electrode layer, light-emitting layer, and electrode layer are sequentially formed as functional layers, and these functional layers are hermetically sealed with a glass substrate or a multilayer film, and the glass sheet and carrier are peeled off Film, thereby obtaining a polyimide substrate film with a functional layer that can be used as an organic EL display. Incidentally, the formation temperature when forming the TFT is 300°C to 500°C.

In addition, in the case of manufacturing a liquid crystal display device using the long polyimide laminate of the present invention, a well-known resist for color filters using vinyl ester resin, phenol resin, acrylic resin, etc. as the base resin may also be used. The agent ink is mounted in the form of a color filter resist layer.

In addition, when manufacturing the various flexible elements described above using the long polyimide laminate of the present invention, in order to improve each characteristic, the following functional layers may also be mounted. That is, in order to improve the abrasion resistance of the polyimide substrate film, well-known compounds such as melamine resin, urethane resin, acrylic resin, silicone resin, silane compound, and metal oxide can also be used as a hard coat layer. Carry. In addition, in order to suppress the permeation of oxygen or water vapor through the polyimide substrate film, well-known gas barrier layers such as aluminum oxide and silicon dioxide may also be mounted. In addition, in order to control the optical properties, dimensional stability, etc. of the polyimide substrate film, well-known transparent resins such as cyclic olefin resins and ester resins may also be mounted in the form of a transparent resin layer.

In addition, in addition to the functional layers described above, copper, silver, gold, titanium, tungsten, ITO can also be used for the transmission and reception of electronic signals between flexible components, between flexible components and output devices, or between flexible components and input devices. Well-known wiring materials such as those are mounted in the form of a wiring layer.

As explained above, the polyimide substrate film with a functional layer obtained by the present invention is excellent in smoothness and has little mixing of foreign matter. Moreover, due to its thin thickness and excellent light transmittance, in addition to various flexible components such as touch screens such as organic EL and other flexible displays, electronic paper, solar cells, etc., it is also used in obtaining vapor deposition masks and fan-out Type wafer level package (Fan out Wafer Level Package, FOWLP) is extremely suitable for substrates and other aspects. [Example]

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to these contents. ＜1. Various physical properties measurement and performance test methods＞ [Measurement of peel strength]

Regarding the peel strength between the carrier film and the carrier film and the peel strength between the carrier film and the polyimide substrate film, these laminates were processed into strips with a width of 1 mm to 10 mm and a length of 10 mm to 25 mm. The carrier film was peeled off in a 180° direction using a tensile testing machine (STROGRAPH-M1) manufactured by Toyo Seiki Co., Ltd. to measure the peel strength. In addition, those with strong peeling strength and difficulty in peeling were set as "unpeelable". [Transmittance]

The polyamide substrate film was cut into 5 cm squares, and the total light transmittance was measured using a haze meter NDH-5000 manufactured by Nippon Denshoku Industries. [Surface roughness Ra]

Regarding the surface roughness Ra of the carrier, carrier film, and polyimide substrate film, cut into 3 cm squares respectively, and use AFM manufactured by Bruker AXS to measure the surface roughness Ra (JIS B0601: 2013) Determination. [CTE]

Regarding the CTE of the carrier, carrier film, and polyimide substrate film, cut into 3 mm×15 mm squares, and use a thermomechanical analysis (TMA) device manufactured by Seiko Instruments to measure the CTE. While applying a load of 5.0 g, a tensile test was carried out at a temperature range of 30°C to 260°C at a constant temperature increase rate (10°C/min), and the CTE ( ×10 ^-6 /K). ＜2. Synthesis of polyamide acid (polyimide precursor) solution＞

The following shows the raw materials used in the synthesis of polyamide acid (polyimide precursor) solutions used in the following synthesis examples or examples and comparative examples, aromatic diamine compounds, and aromatic tetracarboxylic acids Anhydrides and solvents.

[Aromatic diamino compound] ×4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB) ×4,4'-diaminodiphenyl ether (4 ,4'-DAPE)

[Anhydride of aromatic tetracarboxylic acid] × pyromellitic dianhydride (PMDA) × 2,2-bis(3,4-dehydrated dicarboxyphenyl) hexafluoropropane (6FDA)

[Solvent] ×N,N-Dimethylacetamide (DMAc) (Synthesis Example 1)

Under nitrogen flow, while stirring TFMB (9.4 g) in a 300 ml separable flask, it was added to 127.5 g of solvent DMAc, heated, and dissolved at 50°C. Then, 6FDA (13.09 g) was added. Thereafter, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, thereby obtaining 200 g of pale white viscous polyamide A varnish. Furthermore, by curing the polyimide A varnish under heating conditions described later, polyimide resin A (CTE: 70 ppm/K) can be obtained. (Synthesis example 2)

Under nitrogen flow, while stirring 4,4'-DAPE (10.753 g) in a 300 ml separable flask, it was added to 170 g of solvent DMAc, heated, and dissolved at 50°C. Then, PMDA (11.747 g) was added. Thereafter, the solution was continuously stirred at room temperature for 3 hours to carry out a polymerization reaction, thereby obtaining 200 g of a pale white viscous polyamide B varnish. Furthermore, by curing the polyimide B varnish under heating conditions described later, polyimide resin B (CTE: 69 ppm/K) can be obtained.

<3. Formation of PI layer by coating> Each material used in the following Examples and Comparative Examples is shown below. ×Long substrate (transport body) Polyimide film (UPILEX S manufactured by Ube Industries Co., Ltd.), thickness of 0.75 mm, CTE: 18 ppm/K. Polyimide film (Kapton 300H manufactured by Toray DuPont Co., Ltd.), thickness of 75 μm, CTE: 27 ppm/K. (Example 1)

The clean UPILEX S (width 508 mm×length 1100 m×thickness 0.75 mm) wound in a roll shape is set as the long substrate 2, and the unwinding part is used as shown in FIG. 1 1. Lip coater (outside the diagram), heat treatment equipment with continuous drying furnace and continuous furnace (first heat treatment equipment 5, second heat treatment equipment 7), and windings for conveying bodies and polyimide laminates The roll-to-roll coating drying and curing device of section 9 and winding section 10, while unwinding at a speed of 8 m/min, coats the polymer applied from Mono pump 4 so that the film thickness becomes 500 μm. Amino acid B varnish. It was dried at 90°C for 2 minutes and 130°C for 1 minute through a continuous drying furnace (first heat treatment device 5) including a plurality of furnaces, and then passed the temperature from the furnace on the sample inlet side to The continuous furnace (the first heat treatment device 5) in which the furnace on the outlet side is raised step by step is heated stepwise from 130°C to 400°C for a total of 20 minutes to form polyimide (polyimide curing Layer) B.

Next, the polyamide A varnish is applied from the Mono pump 6 and the polyimide B is applied so that the film thickness becomes 150 μm, and the polyamide A varnish is applied through a continuous drying furnace including a plurality of furnaces. (Second heat treatment device 7) and drying at 90°C for 2 minutes, and drying at 130°C for 1 minute, and then the temperature of the sample is increased stepwise from the furnace on the inlet side of the sample to the furnace on the outlet side through multiple furnaces. The furnace (the second heat treatment device 7) is heated stepwise from 130°C to 400°C for a total of 10 minutes to form polyimide (polyimide hardened layer) A. Furthermore, while peeling off the UPILEX S as the long base material 2, the laminate 8 of polyimide B and polyimide A was wound by the winding part 10 to obtain the example 1 Roll-shaped polyimide laminate.

Regarding the thickness of each layer of the obtained polyimide laminate 8, polyimide B was 50 μm, and polyimide A was 15 μm. In addition, the peel strength between UPILEX S (long substrate) and polyimide B is 0.12 N/m, and the peel strength between polyimide B and polyimide A is 0.10 N/m, and either can be easily peeled off. On the other hand, the surface roughness Ra of polyimide A after peeling off in the respective interfaces is 1.0 nm, the surface roughness Ra of polyimide B is 1.0 nm, and the surface roughness Ra of polyimide B is 1.0 nm. The surface roughness Ra is 1.15 nm. Furthermore, the light transmittance of polyimide A was 91%.

Next, with regard to the roll-shaped polyimide laminate 8 obtained as described above, a roll pair including the unwinding part 13, the conveying roller 14, the process processing part 15, and the winding part 17 as shown in FIG. 4 was used. The continuous manufacturing apparatus of the roll system forms the functional layer in the following manner. That is, the polyimide laminate 8 is conveyed at a speed of 5 m/min, and is rolled out in the longitudinal direction so that the polyimide A surface of the polyimide substrate film is upward, and passes through the conveying roller 14 The process is introduced into the process processing section 15 provided in the vacuum chamber, and the process processing section 15 performs continuous processing on the polyimide A surface by sputtering to form ITO with a film thickness of 50 nm. Then, the polyimide laminate 16 with a functional layer including ITO is wound into a roll shape by the winding part 17.

Regarding the polyimide laminate 16 with a functional layer obtained as described above, it was rolled out and cut into a sheet of 370 mm×450 mm, and the ITO film formed was subjected to a XY transparent circuit. Processing. At this time, the intersection of the Y circuit and the X circuit does not form a circuit.

Then, the overcoat is applied at the intersection of the Y circuit and the X circuit and heat-treated at 250°C to harden the overcoat, and the silver paste is used to bridge the overcoat to complete the XY circuit. The entire surface of the film formation side was coated with an overcoat again, and an annealing treatment was performed at 270°C, and the overcoat was hardened and ITO was crystallized.

Then, an optical clear adhesive tape (Optically Clear Adhesive Tape (OCA), 8146-2 manufactured by 3M) was attached to the surface of the re-coated overcoat, and a cover glass was attached to it. Thereafter, the polyimide B as the carrier film was mechanically peeled off, thereby completing a flexible touch screen substrate. (Comparative example 1)

The roll-to-roll coating, drying and curing device shown in Figure 1 unwinds the clean Kapton 300H (width 520 mm x length) at a speed of 8 m/min. 1100 m×thickness 75 μm, surface roughness Ra=4.0 nm), while applying polyamide A varnish from Mono pump 4 so that the film thickness becomes 150 μm, it passes through a continuous furnace including multiple furnaces. Drying furnace is used for drying at 90°C for 2 minutes and at 130°C for 1 minute, and then passing through a continuous furnace including a plurality of furnaces in which the temperature increases stepwise from the sample inlet side furnace to the exit side furnace, from 130°C Stepwise heating is performed until 400° C. for a total of 10 minutes to form polyimide A with a thickness of 15 μm. Then, a laminate of Kapton 300H and polyimide A was wound to obtain a roll-shaped polyimide laminate of Comparative Example 1.

Here, since the obtained roll-shaped polyimide laminate was not able to peel off the polyimide A from Kapton 300H, the formation of a functional layer was not performed. In addition, the surface roughness Ra of the exposed surface of the polyimide A was 1.0 nm.

1‧‧‧Unwinding roller (unwinding part) 2‧‧‧Long substrate (conveying body) 3.‧‧Transporting roller (guide roller) 4‧‧‧The first Mono pump 5‧‧‧The first heat treatment device 6‧‧‧Second Mono pump 7.‧‧‧Second heat treatment device 8.‧‧‧Polyimide laminate 9.‧‧‧Winding roller (winding part) for conveying body 10‧‧‧Polyimide Laminated body winding roller (winding part) 11‧‧‧ endless belt (conveying body) 12‧‧‧metal roller (conveying body) 13‧‧‧ unwinding roller (unwinding part) 14‧‧‧conveying roller ( Guide roller) 15‧‧‧Processing part 16‧‧‧Polyimide laminate with functional layer 17‧‧‧Winding roller (winding part)

Fig. 1 is a schematic explanatory view showing a roll-to-roll coating, drying and curing device used in the process of obtaining a polyimide laminate. Fig. 2 is a schematic explanatory view showing an endless belt type coating, drying and curing device used in the process of obtaining a polyimide laminate. Fig. 3 is a schematic explanatory view showing a metal drum type coating, drying and hardening device used in the process of obtaining a polyimide laminate. Fig. 4 is a schematic explanatory view showing a continuous manufacturing apparatus of a roll-to-roll system for forming a functional layer on a polyimide laminate.

1‧‧‧Unwinding roller (unwinding part)

2‧‧‧Long substrate (conveying body)

3‧‧‧Conveying roller (guide roller)

4‧‧‧The first Mono pump

5‧‧‧The first heat treatment device

6‧‧‧Second Mono Pump

7‧‧‧Second heat treatment device

8‧‧‧Polyimide laminate

9‧‧‧Winding roller for conveying body (winding part)

10‧‧‧Winding roller for polyimide laminate (winding part)

Claims (19)

A method for manufacturing a polyimide substrate film with a functional layer, which is characterized in that: a first solution containing a polyimide precursor or a polyimide resin solution is applied to a continuously supplied conveying body to perform a first heat treatment , At least a non-stick surface is formed on the surface of the first solution, and then a second solution containing a polyimide precursor or a polyimide resin solution is applied to perform a second heat treatment, thereby obtaining a long polyimide An amine laminate, the long polyimide laminate is provided with a first polyimide hardened layer composed of the first solution and a second polyimide hardened layer composed of the second solution, and The traveling direction of the conveying body is the longitudinal direction and is separated from the conveying body, and then the first polyimide hardened layer and the second polyimide of the long polyimide laminate are hardened One of the layers is set as a polyimide substrate film, and the other is set as a carrier film. After a functional layer is formed on the polyimide substrate film, the carrier film is separated to obtain the functional layer The polyimide substrate film. The method for producing a polyimide substrate film with a functional layer as described in claim 1, wherein the long polyimide laminate is temporarily wound on a winding roller, and the polyimide laminate is wound up In the polyimide laminate, the functional layer is continuously formed on the polyimide substrate film, or while the polyimide laminate is rolled out, it is cut into a sheet with a predetermined length. For each sheet-shaped polyimide laminate, the functional layer is formed on the polyimide substrate film. The polyfunctional layer described in item 1 or item 2 of the scope of patent application The method for producing an imide substrate film, wherein in the process of obtaining the long polyimide laminate, the transport body is separated before the second heat treatment is performed, or after the second heat treatment is performed Separate. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the conveying body is a metal roller, an endless belt, or a long base material wound in a roll shape. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the carrier film comprises the first polyimide hardened layer, and the polyimide The amine substrate film includes the second polyimide cured layer. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of patent application, wherein the polyimide substrate film includes the first polyimide hardened layer, and The carrier film includes the second polyimide hardened layer. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the first containing the polyimide resin solution is coated on the conveying body The solution is subjected to the first heat treatment with a maximum temperature of 60°C to 300°C, and the non-stick surface is formed on the surface of the first solution. The method for producing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the carrier is coated with the first polyimide precursor containing the polyimide precursor. The solution is subjected to a first heat treatment with a maximum temperature of 100°C to 450°C to form the first polyimide hardened layer composed of the first solution. The polyfunctional layer described in item 1 or item 2 of the scope of patent application The manufacturing method of the imine substrate film, wherein the maximum temperature of the heat treatment in the second heat treatment is 100°C to 450°C. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the first polyimide hardened layer and the second polyimide hardened layer The interlayer adhesion strength is 1N/m~20N/m, and the thickness of the first polyimide hardened layer or the second polyimide hardened layer as the polyimide substrate film is 1μm~ 50μm. The method for producing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the first polyimide hardened layer as the polyimide substrate film is or The total light transmittance of the second polyimide cured layer is 80% or more. The method for producing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of the patent application, wherein the conveying body comprises a long substrate rolled into a roll, and the long substrate is a An imide film, SUS foil, copper foil, or a composite body in which two or more of these are laminated. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of patent application, which uses two or more kinds of polyimide precursors or polyimine The first solution of the resin solution is applied by overlaying these to form the first polyimide cured layer. The method for manufacturing a polyimide substrate film with a functional layer as described in item 1 or item 2 of the scope of patent application, which uses two or more kinds of polyimide precursors or polyimine The second solution of the resin solution is over-coated with these To form the second polyimide hardened layer. A long polyimide laminate with a functional layer, characterized in that: relative to the long side direction of the long polyimide laminate on which a carrier film and a polyimide substrate film are laminated, the polyimide A functional layer is continuously formed on a substrate film, and the carrier film includes a polyimide cured by curing one of a first solution or a second solution containing a polyimide precursor or a polyimide resin solution Layer, the polyimide substrate film includes hardening the other of the first solution or the second solution containing the polyimide precursor or the polyimide resin solution The polyimide hardened layer, the thickness of the polyimide substrate film is 1 μm-50 μm, the total light transmittance is more than 80%, and the interface with the carrier film has an arithmetic average roughness Ra of 0 nm With a surface roughness of ~5nm, the interlayer adhesion strength of the carrier film and the polyimide substrate film is 1N/m-20N/m. The long polyimide laminate with a functional layer as described in item 15 of the scope of patent application, wherein the functional layer is an indium tin oxide film. The long polyimide laminate with a functional layer as described in item 15 of the scope of patent application, wherein the functional layer is a thin film transistor. The long polyimide laminate with a functional layer as described in item 15 of the scope of patent application, wherein the functional layer is selected from the group consisting of wiring layers, conductive layers, gas barrier layers, thin film transistors, electrode layers, and light emitting layers. , An adhesive layer, a transparent resin layer, a color filter resist, and a hard coat layer consisting of any one or a combination of two or more layers. A long polyimide substrate film with a functional layer, which is characterized in that: For the long side direction of the long polyimide substrate film, a functional layer is continuously formed. The long polyimide substrate film includes hardening a solution containing a polyimide precursor or a polyimide resin solution. The polyimide hardened layer, the thickness of the long polyimide substrate film is 1μm~50μm, and the total light transmittance under the thickness of 20μm is 80% or more, and the surface opposite to the functional layer has The arithmetic average roughness Ra is the surface roughness of 0nm~5nm.

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