WO2022113415A1

WO2022113415A1 - Laminate

Info

Publication number: WO2022113415A1
Application number: PCT/JP2021/025411
Authority: WO
Inventors: 桂也 ▲徳▼田; 哲雄奥山; 直樹渡辺; 正幸横山; 治美米虫; 伝一朗水口
Original assignee: 東洋紡株式会社
Priority date: 2020-11-27
Filing date: 2021-07-06
Publication date: 2022-06-02
Also published as: JPWO2022113415A1

Abstract

This laminate comprises an inorganic substrate, a silane coupling agent layer, and an easily peelable layer in this order. The easily peelable layer has a structural unit derived from biphenyltetracarboxylic acid dianhydride and diaminobenzanilide.

Description

Laminate

The present invention relates to a laminated body.

In recent years, technological development for forming these elements on a polymer film has been actively carried out for the purpose of reducing the weight, size and thickness, and flexibility of functional elements such as semiconductor elements, MEMS elements, and display elements. That is, as a material for a base material of electronic parts such as information communication equipment (broadcasting equipment, mobile radio, portable communication equipment, etc.), radar, high-speed information processing equipment, etc., conventionally, it has heat resistance and a signal of the information communication equipment. Ceramics that can handle higher frequencies in the band (reaching the GHz band) have been used, but since ceramics are not flexible and difficult to thin, there is a drawback that the applicable fields are limited, so recently. A polymer film is used as a substrate.

When forming functional elements such as semiconductor elements, MEMS elements, and display elements on the surface of polymer films, it is ideal to process them by a so-called roll-to-roll process that utilizes the flexibility that is a characteristic of polymer films. It is said that. However, in industries such as the semiconductor industry, the MEMS industry, and the display industry, process techniques for rigid flat substrates such as wafer-based or glass substrate-based have been constructed so far. Therefore, in order to form a functional element on a polymer film using the existing infrastructure, the polymer film is bonded to a rigid support made of an inorganic substance such as a glass plate, a ceramic plate, a silicon wafer, or a metal plate. A process is used in which a desired element is formed on the element and then peeled off from the support.

By the way, in the process of forming a desired functional element in a laminated body in which a polymer film and a support made of an inorganic substance are bonded together, the laminated body is often exposed to a high temperature. For example, in the formation of functional elements such as polysilicon and oxide semiconductors, a process in a temperature range of about 200 ° C. to 600 ° C. is required. Further, in the production of a hydrided amorphous silicon thin film, a temperature of about 200 to 300 ° C. may be applied to the film, and further, in order to heat and dehydrogenate the amorphous silicon to obtain low temperature polysilicon, the temperature is about 450 ° C. to 600 ° C. Heating may be required. Therefore, the polymer film constituting the laminated body is required to have heat resistance, but as a practical matter, the polymer film that can withstand practical use in such a high temperature range is limited. In addition, it is generally conceivable to use an adhesive or an adhesive for bonding the polymer film to the support, but at that time, the bonding surface between the polymer film and the support (that is, the adhesive for bonding) Adhesive) is also required to have heat resistance. However, since ordinary adhesives and adhesives for bonding do not have sufficient heat resistance, bonding with an adhesive or adhesive cannot be applied when the formation temperature of the functional element is high.

Since it is considered that there is no pressure-sensitive adhesive or adhesive having sufficient heat resistance, conventionally, in the above-mentioned applications, a polymer solution or a polymer precursor solution is applied onto an inorganic substrate and used on the inorganic substrate. The technique of drying and curing to form a film and using it for this purpose was adopted. However, since the polymer film obtained by such means is brittle and easily torn, the functional element formed on the surface of the polymer film is often destroyed when peeled from the inorganic substrate. In particular, it is extremely difficult to peel off a large-area film from an inorganic substrate, and it is not possible to obtain an industrially viable yield.
In view of these circumstances, as a laminate of a polymer film and an inorganic substrate for forming a functional element, a polyimide film having excellent heat resistance, toughness, and thinning is possible through an inorganic substrate via a silane coupling agent. A laminate bonded to the above has been proposed (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 5152104 Japanese Patent No. 5304490 Japanese Patent No. 5531781

In the above-mentioned laminate, the inorganic substrate is made of polyimide before or during device formation by interposing a layer containing a silane coupling agent (hereinafter, also referred to as a silane coupling agent layer) between the inorganic substrate and the polyimide film. In addition to preventing the film from peeling off, the inorganic substrate can be easily peeled off from the polyimide film after the device is formed. That is, in the above-mentioned laminate, the silane coupling agent physically or chemically intervenes between the inorganic substrate and the polyimide film to enhance the initial adhesive force between the two. Further, by using the silane coupling agent, it is suppressed that the adhesive force between the two is increased by the heat at the time of forming the device.

However, even when the silane coupling agent layer is interposed between the inorganic substrate and the polyimide film, the present inventors may obtain a silane coupling agent layer (inorganic substrate) depending on the type of the polymer film. We have found a problem that the peelability of silane may not be sufficient.

In this regard, the present inventors conducted further diligent research. As a result, if an easily peelable layer having a specific composition is provided between the polymer film and the silane coupling agent layer, surprisingly, regardless of the type of the polymer film, it is easy to easily perform after device formation. It has been found that the inorganic substrate can be peeled off from the polymer film. Further, if the easily peelable layer itself having a specific composition is used as a film for forming a device, the inorganic substrate can be easily peeled off from the easily peelable layer (film for forming a device) after the device is formed. I found. From the above, the present invention has been completed.

That is, the present invention provides the following.
(1) An inorganic substrate, a silane coupling agent layer, and an easily peelable layer are provided in this order.
The easily peelable layer is a laminate characterized by having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide.

According to the above configuration, since the easily peelable layer is provided on the silane coupling agent layer, if the easily peelable layer itself is used as a film for forming a device, the inorganic substrate can be easily attached to the easily peelable layer (device) after the device is formed. It can be peeled off from the forming film). Further, when the heat-resistant polymer film is further provided on the easily peelable layer, the heat-resistant polymer film and the silane coupling agent layer have the easily peelable layer, so that the heat resistance is high. Regardless of the type of the molecular film (film for forming the device), the inorganic substrate can be easily peeled off from the heat-resistant polymer film after the device is formed. This is clear from the results of the examples. The reason for this is that the easily peelable layer has a structural unit derived from biphenyltetracarboxylic acid dianhydride and diaminobenzanilide, so that the structural unit is highly oriented when it is made into a sheet, and the peeling is performed. It is speculated that cleavage is more likely to occur.

(2) In the configuration of (1), the 90 ° peel strength between the easily peelable layer and the inorganic substrate after heating at 450 ° C. for 1 hour is preferably 0.3 N / cm or less.

When the 90 ° peel strength is 0.3 N / cm or less, the inorganic substrate is easily peeled from the easy peel layer after the device is formed on the easy peel layer.

(3) In the configuration of (1) or (2), it is preferable that the 90 ° initial peel strength between the easily peelable layer and the inorganic substrate is 0.03 N / cm or more.

When the 90 ° initial peel strength is 0.03 N / cm or more, it is possible to prevent the easy peel layer from peeling from the inorganic substrate before or during the formation of the device on the easy peel layer.

(4) In the configuration of (1), it is also preferable to provide a heat-resistant polymer film on the easily peelable layer.

When the heat-resistant polymer film is provided on the easily peelable layer, the easily peelable layer is present between the heat-resistant polymer film and the silane coupling agent layer. Therefore, the heat-resistant polymer film (for device formation) is formed. Regardless of the type of film), the inorganic substrate can be easily peeled off from the heat-resistant polymer film after the device is formed.

(5) In the configuration of (4), the 90 ° peel strength between the heat-resistant polymer film and the inorganic substrate after heating at 450 ° C. for 1 hour is preferably 0.3 N / cm or less.

When the 90 ° peel strength is 0.3 N / cm or less, the inorganic substrate and the heat-resistant polymer film are easily peeled off after the device is formed.

(6) In the configuration of (4) or (5), the 90 ° initial peel strength between the heat-resistant polymer film and the inorganic substrate is preferably 0.03 N / cm or more.

When the 90 ° initial peel strength is 0.03 N / cm or more, it is possible to prevent the heat-resistant polymer film from peeling from the inorganic substrate before or during device formation.

According to the present invention, it is possible to provide a laminate capable of easily peeling an inorganic substrate from a film for forming a device after forming the device.

It is a schematic diagram of the experimental apparatus which applies a silane coupling agent to a glass substrate.

Hereinafter, embodiments of the present invention will be described.

The laminated body according to this embodiment is
An inorganic substrate, a silane coupling agent layer, and an easily peelable layer are provided in this order.
The easily peelable layer has a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide.

Since the laminate has an easily peelable layer on the silane coupling agent layer, if the easily peelable layer itself is used as a film for forming a device, the inorganic substrate can be easily peeled off (device formation) after the device is formed. It is possible to peel off from the film). Further, when the heat-resistant polymer film is further provided on the easily peelable layer, the heat-resistant polymer film and the silane coupling agent layer have the easily peelable layer, so that the heat resistance is high. Regardless of the type of the molecular film (film for forming the device), the inorganic substrate can be easily peeled off from the heat-resistant polymer film after the device is formed.

The 90 ° peel strength between the easily peelable layer and the inorganic substrate after heating at 450 ° C. for 1 hour is preferably 0.3 N / cm or less, and more preferably 0.29 N / cm. Below, it is more preferably 0.28 N / cm or less. The 90 ° peel strength is preferably 0.03 N / cm or more, more preferably 0.05 N / cm or more, and further preferably 0.07 N / cm or more. When the 90 ° peel strength is 0.3 N / cm or less, the inorganic substrate and the easily peelable layer are easily peeled off after the device is formed. Further, when the 90 ° peel strength is 0.03 N / cm or more, it is possible to prevent the inorganic substrate from peeling from the easily peelable layer at an unintended stage such as during device formation.
The 90 ° peel strength is such that a structure having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide is adopted as the structure of the easy peel layer, and conditions for forming a sheet (particularly). , Imidization conditions).
The measurement conditions for the 90 ° peel strength are according to the method described in the examples.

The 90 ° initial peel strength between the easily peelable layer and the inorganic substrate of the laminated body is preferably 0.03 N / cm or more, more preferably 0.05 N / cm or more, still more preferably 0.07 N. / Cm or more. The 90 ° initial peel strength is preferably 0.3 N / cm or less, more preferably 0.29 N / cm or less, and further preferably 0.28 N / cm or less. When the 90 ° initial peel strength is 0.03 N / cm or more, it is possible to prevent the easy peel layer from peeling from the inorganic substrate before or during device formation. Further, when the 90 ° initial peel strength is 0.3 N / cm or less, the inorganic substrate and the easily peelable layer are easily peeled off after the device is formed. That is, when the 90 ° initial peel strength is 0.3 / cm or less, even if the peel strength between the inorganic substrate and the easy peel layer is slightly increased during device formation, both are easily peeled. ..
The 90 ° initial peel strength is determined by adopting a structure having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide as the structure of the easy peel layer, and conditions for forming a sheet (the conditions for forming a sheet). In particular, it can be controlled by the imidization condition).
The measurement conditions for the 90 ° initial peel strength are the same as the measurement conditions for the 90 ° peel strength.
In the present specification, the 90 ° initial peel strength refers to the 90 ° peel strength between the inorganic substrate and the easy peeling layer after the laminated body is heat-treated at 100 ° C. for 10 minutes in an atmospheric atmosphere.

It is preferable that the laminated body further includes a heat-resistant polymer film on the easily peelable layer. When the heat-resistant polymer film is provided on the easily peelable layer, the easily peelable layer is present between the heat-resistant polymer film and the silane coupling agent layer. Therefore, the heat-resistant polymer film (for device formation) is formed. Regardless of the type of film), the inorganic substrate can be easily peeled off from the heat-resistant polymer film after the device is formed.

When the heat-resistant polymer film is provided, it is preferable that the 90 ° peel strength between the heat-resistant polymer film and the inorganic substrate after heating at 450 ° C. for 1 hour is 0.3 N / cm or less. , More preferably 0.29 N / cm or less, still more preferably 0.28 N / cm or less. The 90 ° peel strength is preferably 0.03 N / cm or more, more preferably 0.05 N / cm or more, and further preferably 0.07 N / cm or more. When the 90 ° peel strength is 0.3 N / cm or less, the inorganic substrate and the heat-resistant polymer film are easily peeled after the device is formed. Further, when the 90 ° peel strength is 0.03 N / cm or more, it is possible to prevent the inorganic substrate from peeling from the heat-resistant polymer film at an unintended stage such as during device formation.
The 90 ° peel strength is such that a structure having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide is adopted as the structure of the easy peel layer, and conditions for forming a sheet (particularly). , Imidization conditions).
The measurement conditions for the 90 ° peel strength are according to the method described in the examples.

When the heat-resistant polymer film is provided, the laminate preferably has a 90 ° initial peel strength between the heat-resistant polymer film and the inorganic substrate of 0.03 N / cm or more, more preferably 0.05 N / cm. It is cm or more, more preferably 0.07 N / cm or more. The 90 ° initial peel strength is preferably 0.3 N / cm or less, more preferably 0.29 N / cm or less, and further preferably 0.28 N / cm or less. When the 90 ° initial peel strength is 0.03 N / cm or more, it is possible to prevent the heat-resistant polymer film from peeling from the inorganic substrate before or during device formation. Further, when the 90 ° initial peel strength is 0.3 N / cm or less, the inorganic substrate and the heat-resistant polymer film are easily peeled off after the device is formed. That is, when the 90 ° initial peel strength is 0.3 N / cm or less, even if the peel strength between the inorganic substrate and the heat-resistant polymer film is slightly increased during device formation, both are easily peeled off. Cheap.
The 90 ° initial peel strength is determined by adopting a structure having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide as the structure of the easy peel layer, and conditions for forming a sheet (the conditions for forming a sheet). In particular, it can be controlled by the imidization condition).
The measurement conditions for the 90 ° initial peel strength are the same as the measurement conditions for the 90 ° peel strength.
In the present specification, the 90 ° initial peel strength refers to the 90 ° peel strength between the inorganic substrate and the heat-resistant polymer film after the laminated body is heat-treated at 100 ° C. for 10 minutes in an atmospheric atmosphere.

<Easy peeling layer>
The easily peelable layer is a polyimide film having a structural unit derived from biphenyltetracarboxylic acid dianhydride and diaminobenzanilide.

Generally, a polyimide film is a green film (hereinafter referred to as a green film) in which a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent is applied to a support for producing a polyimide film and dried. (Also referred to as "precursor film" or "polyamic acid film"), and the green film is heat-treated at high temperature to perform a dehydration ring closure reaction on or in a state of being peeled off from the support for producing a polyimide film. It can be obtained by. Here, the green film refers to a polyamic acid film containing a solvent and having self-supporting properties. The solvent content of the green film is not particularly limited as long as it has self-supporting property, but is preferably 1% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more. Yes, more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Further, it is preferably 80% by mass or less, more preferably 70% by mass or less, further preferably 60% by mass or less, and particularly preferably 50% by mass or less.
As another method, a polyimide solution obtained by a dehydration ring closure reaction between diamines and tetracarboxylic acids in a solvent is applied to a support for producing a polyimide film, dried, and contains, for example, 1 to 50% by mass of a solvent. It can also be obtained by treating a polyimide film containing a solvent of 1 to 50% by mass at a high temperature and drying it on a support for producing a polyimide film or in a state of being peeled off from the support.

In this embodiment, diaminobenzanilide is used as the diamines for obtaining the easily peelable layer. As the diaminobenzanilide, 4,4'-diaminobenzanilide (hereinafter, also referred to as DABAN) is preferable.

The content of the diaminobenzanilide (particularly DABAN) is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass when the total diamine component is 100% by mass. % Or more, particularly preferably 100% by mass.

The diamines other than the diaminobenzanilide are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines and the like usually used for polyimide synthesis can be used. More preferably, diamines used in the heat-resistant polymer film described later can be used.

Further, in the present embodiment, biphenyltetracarboxylic acid dianhydride is used as the tetracarboxylic acids for obtaining the easily peelable layer. As the biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (hereinafter, also referred to as BPDA) is preferable. More preferably, tetracarboxylic acids used in the heat-resistant polymer film described later can be used.

The content of the biphenyltetracarboxylic acid dianhydride (particularly BPDA) is preferably 80% by mass or more, more preferably 90% by mass or more, when the total tetracarboxylic acid component is 100% by mass. , More preferably 95% by mass or more, and particularly preferably 100% by mass.

The tetracarboxylic acids other than the biphenyltetracarboxylic acid dianhydride are not particularly limited, and aromatic tetracarboxylic acids (including the acid anhydride thereof) and aliphatic tetracarboxylic acids (the acid anhydride thereof) usually used for polyimide synthesis are not particularly limited. (Including the substance), alicyclic tetracarboxylic acids (including the acid anhydride thereof) can be used. When these are acid anhydrides, the number of anhydride structures in the molecule may be one or two, but those having two anhydride structures (dianhydride) are preferable. good.

As described above, since the easily peelable layer uses diaminobenzanilide as the diamines for obtaining the easily peelable layer and biphenyltetracarboxylic acid dianhydride as the tetracarboxylic acids, the easily peelable layer is biphenyltetra. It will have a structural unit derived from carboxylic acid dianhydride and diaminobenzanilide.

The easily peelable layer preferably has a structural unit derived from BPDA and DABAN. When the total structural units contained in the easily peelable layer are 100% by mass, the total of the structural units derived from BPDA and DABAN is preferably 80% by mass or more, more preferably 90% by mass or more. It is more preferably 95% by mass or more, and particularly preferably 100% by mass.

The easily peelable layer may contain a composition other than BPDA and polyimide having a structural unit derived from DABAN. The content of the polyimide (BPDA and the polyimide having a structural unit derived from DABAN) contained in the easily peelable layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further. It is preferably 95% by mass or more, and may be 100% by mass.
The composition other than BPDA and polyimide having a structural unit derived from DABAN is not particularly limited as long as it does not contradict the gist of the present invention.

The easily peelable layer preferably has a melting point of 250 ° C. or higher, more preferably 300 ° C. or higher, and even more preferably 400 ° C. or higher. When the melting point is 250 ° C. or higher, the heat resistance is more excellent. Further, the easily peelable layer preferably has a glass transition temperature of 200 ° C. or higher, more preferably 320 ° C. or higher, and further preferably 380 ° C. or higher. When the glass transition temperature is 200 ° C. or higher, the heat resistance is more excellent. In the present specification, the melting point and the glass transition temperature are determined by differential thermal analysis (DSC). When the melting point exceeds 500 ° C., it is determined whether or not the melting point has been reached by visually observing the thermal deformation behavior when heated at the corresponding temperature.

As described above, the easily peelable layer is a polyamic acid (polyimide precursor) solution obtained by reacting biphenyltetracarboxylic acid dianhydride (tetracarboxylic acids) and diaminobenzanilide (diamines) in a solvent. Is applied to a support for producing a polyimide film and dried to obtain a green film (also referred to as “polyimide acid film”), and the green film is heated at a high temperature on the support for producing a polyimide film or in a state of being peeled off from the support. It is obtained by heat treatment to carry out a dehydration ring closure reaction.
As another method, a polyimide solution obtained by a dehydration ring closure reaction with biphenyltetracarboxylic acid dianhydride (tetracarboxylic acids) and diaminobenzanilide (diamines) in a solvent is used as a support for producing a polyimide film. It is coated and dried to form a polyimide film containing, for example, 1 to 50% by mass of a solvent, and further, a polyimide containing 1 to 50% by mass of a solvent on a support for producing a polyimide film or in a state of being peeled off from the support. It can also be obtained by treating the film at a high temperature and drying it.

The solvent used when polymerizing biphenyltetracarboxylic acid dianhydride and diaminobenzanilide to obtain polyamic acid is not particularly limited as long as it dissolves both the raw material monomer and the produced polyamic acid. Polar organic solvents are preferred, for example N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, hexamethyl. Examples thereof include phosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. Of these, N-methyl-2-pyrrolidone and N, N-dimethylacetamide are preferably applied. These solvents can be used alone or in admixture. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material, and the specific amount used is such that the mass of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by mass. The amount is preferably 10 to 20% by mass.

The polyamic acid can be produced by a known production method. That is, one or more kinds of tetracarboxylic acid anhydrous components (including biphenyltetracarboxylic acid dianhydride) and one or more kinds of diamine components (including diaminobenzanilide) which are raw materials are used. , Polymerize in the solvent to obtain a polyamic acid solution. The reaction apparatus is preferably equipped with a temperature adjusting device for controlling the reaction temperature, and the reaction temperature is preferably 0 ° C. or higher and 80 ° C. or lower, and further 15 ° C. or higher and 60 ° C. or lower is the reverse of polymerization. It is preferable because it suppresses the hydrolysis of the polyamic acid, which is a reaction, and the viscosity of the polyamic acid tends to increase.

If necessary, an imidization catalyst, inorganic fine particles, or the like may be added to the polyamic acid solution.

It is preferable to use a tertiary amine as the imidization catalyst. As the tertiary amine, a heterocyclic tertiary amine is preferable. Preferred specific examples of the heterocyclic tertiary amine include pyridine, 2,5-diethylpyridine, picoline, quinoline, isoquinoline and the like. The amount of the imidization catalyst used is preferably 0.01 to 2.00 equivalents, more preferably 0.02 to 1.20 equivalents, relative to the reaction site of the polyamic acid (polyimide precursor). When the amount of the imidization catalyst used is 0.01 equivalent or more, the effect of the catalyst can be sufficiently obtained. Further, when the amount of the imidization catalyst used is 2.00 equivalents or less, the proportion of the catalyst not involved in the reaction can be reduced, which is preferable in terms of cost.

Examples of the inorganic fine particles include inorganic oxide powders such as fine-grained silicon dioxide (silica) powder and aluminum oxide powder; and inorganic salt powders such as fine-grained calcium carbonate powder and calcium phosphate powder. If the inorganic fine particles are present as coarse particles, they may cause defects in the next and subsequent steps. Therefore, it is preferable that the inorganic fine particles are uniformly dispersed in the polyamic acid solution. ..

Conventional methods such as spin coating, doctor blade, applicator, comma coater, screen printing method, slit coating, reverse coating, dip coating, curtain coating, and slit die coating have been applied to the polyamic acid (polyimide precursor) solution or the polyimide solution. A known solution coating means can be appropriately used.

The reduced viscosity (ηsp / C) of the polyamic acid solution or the polyimide solution is preferably 0.1 or more, more preferably 1 or more, and further preferably 2 or more. Further, it is preferably 5 or less, more preferably 4.5 or less, and further preferably 4 or less.

As the drying conditions for obtaining the green film (drying conditions for the applied polyamic acid), for example, when N, N-dimethylacetamide is used as a solvent, the drying temperature is preferably 70 to 130 ° C., more preferably 80. It is about 125 ° C., more preferably 85 to 120 ° C. By setting the drying temperature to 130 ° C. or lower, it is possible to prevent the green film from becoming brittle due to a decrease in molecular weight. Further, by setting the drying temperature to 130 ° C. or lower, it is possible to prevent the imidization from partially progressing during the production of the green film and making it difficult to obtain the desired physical properties during the imidization step. Further, by setting the drying temperature to 70 ° C. or higher, it is possible to suppress a long drying time, a tendency for a decrease in molecular weight, and a decrease in handleability due to insufficient drying. The drying time is preferably 5 to 90 minutes, more preferably 15 to 80 minutes, although it depends on the drying temperature. By setting the drying time to 90 minutes or less, it is possible to suppress a decrease in molecular weight and brittleness of the film. Further, by setting the drying time to 5 minutes or more, it is possible to suppress deterioration of handleability due to insufficient drying.
Conventionally known drying devices can be applied, and examples thereof include hot air, hot nitrogen, far infrared rays, and high frequency induction heating.

As a specific method for imidizing the green film, it is preferable to perform a heat treatment in a plurality of steps to imidize the green film. The number of steps is preferably 2 or more, and more preferably 3 or more. The number of steps is preferably 10 or less, more preferably 5 or less.
By setting the number of steps to 2 or more (more preferably 3 or more), it is possible to prevent rapid evaporation of the solvent due to rapid heating. As a result, the surface smoothness can be improved. Further, by setting the number of steps to 2 or more (more preferably 3 or more), the molecules can move easily, and the tension control can easily increase the molecular orientation.
On the other hand, if the number of steps is too large, a temperature range in which a reverse reaction is likely to occur is used, and the mechanical properties of the obtained polyimide film may deteriorate. Therefore, by setting the number of steps to 10 or less, it is possible to suppress deterioration of the mechanical properties of the obtained polyimide film.
When imidization (heat treatment) is performed in three steps, the temperature and time in each step are set from the following viewpoints.
First step: By preferably removing the residual solvent, the thickness unevenness of the film is reduced.
1st to 2nd steps: Imidization and tension control are performed with a certain amount of solvent remaining to achieve high orientation. Also, avoid temperature ranges where reverse reactions are likely to occur.
Third step: The imidization is completed and the terminals produced by the reverse reaction are recombined.
Specifically, when imidization (heat treatment) is performed in three steps, the preferable range of temperature and time in each step is as follows.
The imidization temperature of the first step is preferably 150 ° C. or higher, more preferably 180 ° C. or higher, and further preferably 180 ° C. or higher, because the thickness unevenness of the film can be reduced by removing the residual solvent. It is preferably 185 ° C. or higher, and particularly preferably 190 ° C. or higher. The imidization temperature of the first step is preferably 220 ° C. or lower, more preferably 210 ° C. or lower.
The imidization time of the first step is preferably 1 minute or longer, more preferably 2 minutes or longer. The imidization time of the first step is preferably 10 minutes or less, more preferably 5 minutes or less.
After the completion of the first step, the imidization reaction (heat treatment) of the second step is performed. The imidization temperature of the second step is preferably 220 ° C. or higher, more preferably 230 ° C. or higher, and further preferably 240 ° C. or higher. The imidization temperature in the second step is preferably 280 ° C. or lower, more preferably 270 ° C. or lower.
The imidization time of the second step is preferably 1 minute or longer, more preferably 2 minutes or longer. The imidization time of the second step is preferably 10 minutes or less, more preferably 5 minutes or less.
After the completion of the second step, the imidization reaction (heat treatment) of the third step is performed. The imidization temperature in the third step is preferably more than 280 ° C, more preferably 290 ° C or higher, and even more preferably 295 ° C or higher. The imidization temperature in the third step is preferably less than 480 ° C, more preferably 400 ° C or lower, still more preferably 350 ° C or lower, because the thickness unevenness of the film can be reduced. be.
The imidization time of the third step is preferably 2 minutes or more, more preferably 4 minutes or more. The imidization time of the third step is preferably 20 minutes or less, more preferably 10 minutes or less.
By going through the above-mentioned plurality of steps, an easily peelable layer with less thickness unevenness of the film can be obtained.

Imidization (heat treatment) is carried out by grasping both ends of the film with a pin tenter or a clip. At that time, in order to maintain the uniformity of the film, it is preferable to make the tension in the width direction and the longitudinal direction of the film as uniform as possible. Specifically, just before the film is applied to the pin tenter, both ends of the film are pressed with a brush so that the pins are evenly pierced into the film. The brush is preferably a rigid and heat-resistant fibrous brush, and a high-strength and high elastic modulus monofilament can be adopted. By satisfying these imidization conditions (temperature, time, tension), the occurrence of orientation strain inside the film (front and back and plane direction) is suppressed, the thickness unevenness and the like are within a predetermined range, and the mechanical properties (particularly) are mechanical. , Tension elastic modulus, tensile breaking strength, etc.) can be sufficiently maintained to obtain an easily peelable layer (polyimide film).

The easily peelable layer is preferably manufactured via a green film of polyamic acid. That is, by imidizing the grease film, a release sheet having more excellent peelability and heat resistance can be obtained.

The easily peelable layer is usually preferably a non-stretched sheet, but may be a uniaxially or biaxially stretched sheet. Here, the non-stretched sheet means a film obtained by tenter stretching, roll stretching, inflation stretching, or the like without intentionally applying a mechanical external force in the surface expansion direction of the film.

The thickness of the easily peelable layer when used by laminating with a polymer film is preferably 5 μm or less, more preferably 3 μm or less, and further preferably 1 μm or less. The lower limit of the thickness of the easily peelable layer is not particularly limited, but is substantially 0.01 μm or more. When the easily peelable layer is 5 μm or less, it is possible to suppress the occurrence of warpage due to the difference in CTE and mechanical properties with the polymer film.
When the easily peelable layer is used as a film for forming a device without being laminated with a polymer film, the thickness of the easily peelable layer is preferably 3 μm or more, more preferably 11 μm or more, still more preferably 13 μm. The above is more preferably 15 μm or more. The upper limit of the thickness of the easily peelable layer is not particularly limited, but is preferably 250 μm or less, more preferably 150 μm or less, still more preferably 90 μm or less for use as a flexible electronic device.

The average CTE of the easily peelable layer between 30 ° C. and 300 ° C. is preferably −5 ppm / ° C. to + 20 ppm / ° C., more preferably −5 ppm / ° C. to + 15 ppm / ° C., and even more preferably 1 ppm. It is from / ° C to + 10 ppm / ° C. When the CTE is within the above range, the difference in the coefficient of linear expansion from that of a general support (inorganic substrate) can be kept small, and the easily peelable layer and the inorganic substrate can be peeled off even when subjected to a heat application process. It can be avoided. In particular, when it is used by laminating it with a polymer film, the CTE difference from the polymer film is small, so that warpage can be suppressed. Here, CTE is a factor that represents reversible expansion and contraction with respect to temperature. The CTE of the easily peelable layer is a value measured for a single film film having the same composition as the easily peelable layer, and is an average of the CTE in the flow direction (MD direction) and the CTE in the width direction (TD direction) of the coating. Point to a value.

The heat shrinkage of the easily peelable layer between 30 ° C. and 500 ° C. is preferably ± 0.9%, more preferably ± 0.6%. The heat shrinkage rate is a factor that represents irreversible expansion and contraction with respect to temperature. The heat shrinkage rate of the easily peelable layer is determined by measuring a single-layer film having the same composition as the easily peelable layer.

<Heat-resistant polymer film>
In the present specification, the heat-resistant polymer is a polymer having a melting point of 400 ° C. or higher, preferably 500 ° C. or higher, and a glass transition temperature of 250 ° C. or higher, preferably 320 ° C. or higher, more preferably 380 ° C. or higher. .. Hereinafter, it is also simply referred to as a polymer in order to avoid complication. In the present specification, the melting point and the glass transition temperature are determined by differential thermal analysis (DSC). When the melting point exceeds 500 ° C., it may be determined whether or not the melting point has been reached by observing and observing the thermal deformation behavior when heated at the corresponding temperature.

The heat-resistant polymer film (hereinafter, also simply referred to as a polymer film) includes polyimide resins such as polyimide, polyamideimide, polyetherimide, and fluorinated polyimide (for example, aromatic polyimide resin and alicyclic polyimide resin); polyethylene. , Polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate and other copolymerized polyesters (eg, fully aromatic polyesters, semi-aromatic polyesters); copolymerized (meth) acrylates typified by polymethylmethacrylate; polycarbonate. Polyimide; Polysulphon; Polyethersulphon; Polyetherketone; Cellulose acetate; Cellulite nitrate; Aromatic polyamide; Polyvinyl chloride; Polyphenol; Polyallylate; Polyphenylene sulfide; Polyphenylene oxide; Polystyrene and other films can be exemplified.
However, since the polymer film is premised on being used in a process involving a heat treatment of 450 ° C. or higher, the polymer films exemplified are limited to those that can be actually applied. Among the polymer films, a film using a so-called super engineering plastic is preferable, and more specifically, an aromatic polyimide film, an aromatic amide film, an aromatic amide imide film, an aromatic benzoxazole film, and an fragrance. Examples thereof include group benzothiazole film and aromatic benzoimidazole film.

The details of the polyimide resin film (sometimes referred to as a polyimide film), which is an example of the polymer film, will be described below. Generally, a polyimide-based resin film is a green film (hereinafter referred to as a green film) in which a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent is applied to a support for producing a polyimide film and dried. It is also referred to as "polyamic acid film"), and is obtained by subjecting a green film to a high-temperature heat treatment on a support for producing a polyimide film or in a state of being peeled off from the support to carry out a dehydration ring closure reaction.

The application of the polyamic acid (polyimide precursor) solution is, for example, application of a conventionally known solution such as spin coating, doctor blade, applicator, comma coater, screen printing method, slit coating, reverse coating, dip coating, curtain coating, and slit die coating. Means can be used as appropriate.

The diamines constituting the polyamic acid are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines and the like usually used for polyimide synthesis can be used. From the viewpoint of heat resistance, aromatic diamines are preferable, and among aromatic diamines, aromatic diamines having a benzoxazole structure are more preferable. When aromatic diamines having a benzoxazole structure are used, it is possible to develop high elastic modulus, low coefficient of thermal expansion, and low linear expansion coefficient as well as high heat resistance. The diamines may be used alone or in combination of two or more.

The aromatic diamines having a benzoxazole structure are not particularly limited, and are, for example, 5-amino-2- (p-aminophenyl) benzoxazole, 6-amino-2- (p-aminophenyl) benzoxazole, 5 -Amino-2- (m-aminophenyl) benzoxazole, 6-amino-2- (m-aminophenyl) benzoxazole, 2,2'-p-phenylenebis (5-aminobenzoxazole), 2,2' -P-Phenylenebis (6-aminobenzoxazole), 1- (5-aminobenzoxazole) -4- (6-aminobenzoxazolo) benzene, 2,6- (4,4'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (4,4-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2, 6- (3,4'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (3,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2,6- (3,3'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (3,3') -Diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole and the like can be mentioned.

Examples of aromatic diamines other than the above-mentioned aromatic diamines having a benzoxazole structure include 2,2'-dimethyl-4,4'-diaminobiphenyl and 1,4-bis [2- (4-aminophenyl). )-2-propyl] benzene (bisaniline), 1,4-bis (4-amino-2-trifluoromethylphenoxy) benzene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4,4 '-Bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl ] Sulfates, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl ] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3'- Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4' -Diaminodiphenylsulfoxide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4, 4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [ 4- (4-Aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] propane, 1, 2-Bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] Propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3 -Bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane , 2,3-Bis [4- (4-aminophenoxy) phenyl] butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] Propane, 2,2-bis [4- (4-aminophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy)- 3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl]- 1,1,1,3,3,3-hexafluoropropane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-) Aminophenoxy) Benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4 -(4-Aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl ] Ether, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3- (3-) Aminophenoxy) benzoyl] benzene, 4,4'-bis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-Aminophenoxy) Benzene] Propane, 3,4'-diaminodiphenylsulfide, 2,2-bis [3- (3-Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoro Propane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] Etan, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4'-bis [3- (4-Aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-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, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] Sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] Benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluorophenoxy) -Α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino) -6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3, 4'-Diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-Diamino-5'-Phenoxybenzophenone, 3,3'-Diamino-4,4'-Dibiphenoxybenzophenone, 4,4'-Diamino-5,5'-Dibiphenoxybenzophenone, 3,4'- Diamino-4,5'-dibiphenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxybenzophenone, 3,4'-Diamino-5'-biphenoxybenzophenone, 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1, 3-Bis (4-amino-5-phenoxybenzoyl) benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-bif) Enoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4) -Amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzonitrile, and one of the hydrogen atoms on the aromatic ring of the aromatic diamine. Part or all of a halogen atom, an alkyl group or an alkoxyl group having 1 to 3 carbon atoms, a cyano group, or a part or all of a hydrogen atom of an alkyl group or an alkoxyl group having 1 to 3 carbon atoms substituted with a halogen atom. Examples thereof include aromatic diamines substituted with an alkyl halide group or an alkoxyl group.

Examples of the aliphatic diamines include 1,2-diaminoethane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,8-diaminootan and the like.
Examples of the alicyclic diamines include 1,4-diaminocyclohexane, 4,4'-methylenebis (2,6-dimethylcyclohexylamine) and the like.
The total amount of diamines (aliphatic diamines and alicyclic diamines) other than aromatic diamines is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less of all diamines. Is. In other words, the aromatic diamines are preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more of all diamines.

Examples of the tetracarboxylic acids constituting the polyamic acid include aromatic tetracarboxylic acids (including its acid anhydride), aliphatic tetracarboxylic acids (including its acid anhydride) and alicyclic tetracarboxylic acids usually used for polyimide synthesis. Acids (including its acid anhydride) can be used. Among them, aromatic tetracarboxylic acid anhydrides and alicyclic tetracarboxylic acid anhydrides are preferable, aromatic tetracarboxylic acid anhydrides are more preferable from the viewpoint of heat resistance, and alicyclics are more preferable from the viewpoint of light transmission. Group tetracarboxylic acids are more preferred. When these are acid anhydrides, the number of anhydride structures in the molecule may be one or two, but those having two anhydride structures (dianhydride) are preferable. good. The tetracarboxylic acids may be used alone or in combination of two or more.

Examples of the alicyclic tetracarboxylic acid include cyclobutanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3', 4,4'-bicyclohexyltetracarboxylic acid and the like. Examples include carboxylic acids and their acid anhydrides. Among these, dianhydrides having two anhydride structures (eg, cyclobutanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3', 4,4 '-Bicyclohexyltetracarboxylic acid dianhydride, etc.) is suitable. The alicyclic tetracarboxylic acids may be used alone or in combination of two or more.
When transparency is important, the alicyclic tetracarboxylic acids are preferably, for example, 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more of all tetracarboxylic acids.

The aromatic tetracarboxylic acids are not particularly limited, but are preferably pyromellitic acid residues (that is, those having a structure derived from pyromellitic acid), and more preferably an acid anhydride thereof. Examples of such aromatic tetracarboxylic acids include pyromellitic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 3. , 3', 4,4'-benzophenone tetracarboxylic acid dianhydride, 3,3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride, 2,2-bis [4- (3,4-di) Carboxylic phenoxy) phenyl] propanoic acid anhydride and the like can be mentioned.
When heat resistance is important, the aromatic tetracarboxylic acids are preferably, for example, 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more of all tetracarboxylic acids.

The thickness of the polymer film is preferably 3 μm or more, more preferably 11 μm or more, further preferably 24 μm or more, and even more preferably 45 μm or more. The upper limit of the thickness of the polymer film is not particularly limited, but is preferably 250 μm or less, more preferably 150 μm or less, still more preferably 90 μm or less for use as a flexible electronic device.

The average CTE of the polymer film between 30 ° C. and 300 ° C. is preferably −5 ppm / ° C. to + 20 ppm / ° C., more preferably −5 ppm / ° C. to + 15 ppm / ° C., still more preferably 1 ppm. It is from / ° C to + 10 ppm / ° C. When the CTE is within the above range, the difference in the coefficient of linear expansion from the general support (inorganic substrate) can be kept small, and the polymer film and the inorganic substrate are peeled off even when subjected to the heat application process. It can be avoided. Here, CTE is a factor that represents reversible expansion and contraction with respect to temperature. The CTE of the polymer film refers to the average value of the CTE in the flow direction (MD direction) and the CTE in the width direction (TD direction) of the polymer film. The method for measuring CTE of the polymer film is as described in Examples.

The thermal shrinkage of the polymer film between 30 ° C. and 500 ° C. is preferably ± 0.9%, more preferably ± 0.6%. The heat shrinkage rate is a factor that represents irreversible expansion and contraction with respect to temperature.

The tensile breaking strength of the polymer film is preferably 60 MPa or more, more preferably 120 MPa or more, and further preferably 240 MPa or more. The upper limit of the tensile breaking strength is not particularly limited, but is practically less than about 1000 MPa. When the tensile breaking strength is 60 MPa or more, it is possible to prevent the polymer film from breaking when peeled from the inorganic substrate. The tensile breaking strength of the polymer film refers to the average value of the tensile breaking strength in the flow direction (MD direction) and the tensile breaking strength in the width direction (TD direction) of the polymer film. The method for measuring the tensile breaking strength of the polymer film is as described in Examples.

The tensile elongation at break of the polymer film is preferably 1% or more, more preferably 5% or more, still more preferably 20% or more. When the tensile elongation at break is 1% or more, the handleability is excellent. The tensile elongation at break of the polymer film refers to the average value of the tensile elongation at break in the flow direction (MD direction) and the tensile elongation at break in the width direction (TD direction) of the polymer film. The method for measuring the tensile elongation at break of the polymer film is as described in Examples.

The tensile elastic modulus of the polymer film is preferably 3 GPa or more, more preferably 6 GPa or more, and further preferably 8 GPa or more. When the tensile elastic modulus is 3 GPa or more, the polymer film is less stretched and deformed when peeled from the inorganic substrate, and is excellent in handleability. The tensile elastic modulus is preferably 20 GPa or less, more preferably 12 GPa or less, and further preferably 10 GPa or less. When the tensile elastic modulus is 20 GPa or less, the polymer film can be used as a flexible film. The tensile elastic modulus of the polymer film refers to the average value of the tensile elastic modulus in the flow direction (MD direction) and the tensile elastic modulus in the width direction (TD direction) of the polymer film. The method for measuring the tensile elastic modulus of the polymer film is as described in Examples.

The thickness unevenness of the polymer film is preferably 20% or less, more preferably 12% or less, still more preferably 7% or less, and particularly preferably 4% or less. When the thickness spot exceeds 20%, it tends to be difficult to apply to a narrow part. The film thickness unevenness can be obtained, for example, by randomly extracting about 10 positions from the film to be measured with a contact-type film thickness meter, measuring the film thickness, and using the following formula.
Film thickness spots (%)
= 100 x (maximum film thickness-minimum film thickness) ÷ average film thickness

The polymer film is preferably obtained in the form of being wound as a long polymer film having a width of 300 mm or more and a length of 10 m or more at the time of its manufacture, and has a roll-like height wound around a winding core. The one in the form of a molecular film is more preferable. When the polymer film is wound in a roll shape, it can be easily transported in the form of a heat-resistant polymer film wound in a roll shape.

In the polymer film, in order to ensure handleability and productivity, a lubricant (particle) having a particle size of about 10 to 1000 nm is added / contained in the polymer film in an amount of about 0.03 to 3% by mass. Therefore, it is preferable to impart fine irregularities to the surface of the polymer film to ensure slipperiness.

<Inorganic substrate>
The inorganic substrate may be a plate-shaped substrate that can be used as a substrate made of an inorganic substance. For example, a glass plate, a ceramic plate, a semiconductor wafer, a metal or the like, and these glass plates and ceramic plates are used. Examples of the semiconductor wafer and the composite of the metal include those in which these are laminated, those in which they are dispersed, and those in which these fibers are contained.

Examples of the glass plate include quartz glass, high silicate glass (96% silica), soda lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pylex (registered trademark)), borosilicate glass (non-alkali), and the like. Includes borosilicate glass (microsheet), aluminosilicate glass and the like. Among these, those having a coefficient of linear expansion of 5 ppm / K or less are desirable, and if they are commercially available products, "Corning (registered trademark) 7059" and "Corning (registered trademark) 1737" manufactured by Corning Inc., which are glass for liquid crystal, are used. "EAGLE", "AN100" manufactured by Asahi Glass Co., Ltd., "OA10" manufactured by Nippon Electric Glass Co., Ltd., "AF32" manufactured by SCHOTT Co., Ltd., etc. are desirable.

The semiconductor wafer is not particularly limited, but is limited to silicon wafer, germanium, silicon-germanium, gallium-arsenic, aluminum-gallium-indium, nitrogen-phosphorus-arsenide-antimony, SiC, InP (indium phosphorus), InGaAs, GaInNAs, and the like. Wafers such as LT, LN, ZnO (zinc oxide), CdTe (cadmium telluride), and ZnSe (zinc selenide) can be mentioned. Among them, the wafer preferably used is a silicon wafer, and particularly preferably a mirror-polished silicon wafer having a size of 8 inches or more.

The metal includes single element metals such as W, Mo, Pt, Fe, Ni, and Au, alloys such as inconel, monel, mnemonic, carbon copper, Fe—Ni-based invar alloy, and superinvar alloy. Further, a multilayer metal plate formed by adding another metal layer or a ceramic layer to these metals is also included. In this case, if the overall coefficient of linear expansion (CTE) with the additional layer is low, Cu, Al, or the like is also used for the main metal layer. The metal used as the additional metal layer is limited as long as it has properties such as strong adhesion to the polymer film, no diffusion, and good chemical resistance and heat resistance. Although not, Cr, Ni, TiN, Mo-containing Cu and the like are preferable examples.

It is desirable that the flat surface portion of the inorganic substrate is sufficiently flat. Specifically, the PV value of the surface roughness is 50 nm or less, more preferably 20 nm or less, and further preferably 5 nm or less. If it is coarser than this, the peel strength between the polymer film layer and the inorganic substrate may be insufficient.

The thickness of the inorganic substrate is not particularly limited, but from the viewpoint of handleability, a thickness of 10 mm or less is preferable, 3 mm or less is more preferable, and 1.3 mm or less is further preferable. The lower limit of the thickness is not particularly limited, but is preferably 0.07 mm or more, more preferably 0.15 mm or more, still more preferably 0.3 mm or more.

<Silane coupling agent layer>
A silane coupling agent layer containing a silane coupling agent is provided on the inorganic substrate.

The silane coupling agent physically or chemically intervenes between the inorganic substrate and the easily peelable layer, and has an effect of enhancing the adhesive force between the inorganic substrate and the easily peelable layer.
The coupling agent is not particularly limited, but a silane coupling agent having an amino group or an epoxy group is preferable. Preferred specific examples of the silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (. Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-Epoxycyclohexyl) Ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, vinyltricrolsilane, Vinyl trimethoxysilane, vinyl triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycid Xipropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-Acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane , 3-Chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isoxapropyltriethoxysilane, tris- (3-trimethoxy) Cyrilpropyl) isocyanurate, chloromethylphenetyltrimethoxysilane, chloromethyltrimethoxysilane, aminophenyltrimethoxysilane, aminophenetyltrimethoxysilane, aminophenylaminomethylphenetyltrimethoxysilane and the like.

In addition to the above, the silane coupling agent includes n-propyltrimethoxysilane, butyltrichlorosilane, 2-cyanoethyltriethoxysilane, cyclohexyltrichlorosilane, decyltrichlorosilane, diacetoxydimethylsilane, diethoxydimethylsilane, and dimethoxy. Didimethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, dodecyllichlorosilane, dodecyltrimethoxylane, ethyltrichlorosilane, hexyltrimethoxysilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, n-octyltrichlorosilane, n-octyltri. Ethoxysilane, n-octyltrimethoxysilane, triethoxyethylsilane, triethoxymethylsilane, trimethoxymethylsilane, trimethoxyphenylsilane, pentyltriethoxysilane, pentyllichlorosilane, triacetoxymethylsilane, trichlorohexylsilane, trichloromethyl Silane, Trichlorooctadecylsilane, Trichloropropylsilane, Trichlorotetradecylsilane, Trimethoxypropylsilane, Allyltrichlorosilane, Allyltriethoxysilane, Allyltrimethoxysilane, Diethoxymethylvinylsilane, Dimethoxymethylvinylsilane, Trichlorovinylsilane, Triethoxyvinylsilane, Vinyltris (2-methoxyethoxy) silane, trichloro-2-cyanoethylsilane, diethoxy (3-glycidyloxypropyl) methylsilane, 3-glycidyloxypropyl (dimethoxy) methylsilane, 3-glycidyloxypropyltrimethoxysilane, etc. can also be used. can.

Among the silane coupling agents, a silane coupling agent having one silicon atom in one molecule is particularly preferable, and for example, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N- 2- (Aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy Examples thereof include propylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, aminophenyltrimethoxysilane, aminophenetyltrimethoxysilane, and aminophenylaminomethylphenetyltrimethoxysilane. When particularly high heat resistance is required in the process, it is desirable to connect Si and an amino group with an aromatic group.
In addition to the above, the coupling agent includes 1-mercapto-2-propanol, 3-mercaptopropionate methyl, 3-mercapto-2-butanol, 3-mercaptopropionate butyl, 3- (dimethoxymethylsilyl)-. 1-Propanethiol, 4- (6-mercaptohexaloyl) benzyl alcohol, 11-amino-1-undecenethiol, 11-mercaptoundecylphosphonic acid, 11-mercaptoundecyltrifluoroacetic acid, 2,2'-( Ethylenedioxy) dietanthiol, 11-mercaptoundecitri (ethylene glycol), (1-mercaptoundic-11-yl) tetra (ethylene glycol), 1- (methylcarboxy) undec-11-yl) hexa (ethylene) Glycol), hydroxyundecyl disulfide, carboxyundecyl disulfide, hydroxyhexadodecyl disulfide, carboxyhexadecyl disulfide, tetrakis (2-ethylhexyloxy) titanium, titanium dioctyloxybis (octylene glycolate), zirconium tributoxymonoacetylacet Nate, zirconium monobutoxyacetylacetonate bis (ethylacetacetate), zirconium tributoxymonostearate, acetalkoxyaluminum diisopropilate, 3-glycidyloxypropyltrimethoxysilane, 2,3-butanedithiol, 1-butanethiol, 2-Butanthiol, Cyclohexanethiol, Cyclopentanethiol, 1-decanethiol, 1-dodecanethiol, 3-mercaptopropionic acid-2-ethylhexyl, 3-mercaptopropionic acid ethyl, 1-heptanethiol, 1-hexadecanethiol, hexyl Mercaptan, Isoamyl mercaptan, Isobutyl mercaptan, 3-mercaptopropionic acid, 3-mercaptopropionic acid-3-methoxybutyl, 2-methyl-1-butanethiol, 1-octadecanethiol, 1-octanethiol, 1-pentadecanethiol, 1 -Pentanthiol, 1-Propanethiol, 1-Tetradecanethiol, 1-Undecanethiol, 1- (12-mercaptododecyl) imidazole, 1- (11-mercaptoundesyl) imidazole, 1- (10-mercaptodecyl) imidazole, 1- (16-mercaptohexadecyl) imidazole, 1- (17-mercapto) Heptadecyl) imidazole, 1- (15-mercapto) dodecanoic acid, 1- (11-mercapto) undecanoic acid, 1- (10-mercapto) decanoic acid and the like can also be used.

<Method of forming the silane coupling agent layer>
As a method for forming the silane coupling agent layer, a method of applying a silane coupling agent solution to the inorganic substrate, a vapor deposition method, or the like can be used. The silane coupling agent layer may be formed on the surface of the easily peelable layer.

As a method of applying the silane coupling agent solution, a spin coating method, a curtain coating method, a dip coating method, a slit die coating method, a gravure coating method, a bar, using a solution obtained by diluting the silane coupling agent with a solvent such as alcohol is used. Conventionally known solution coating means such as a coating method, a comma coating method, an applicator method, a screen printing method, and a spray coating method can be appropriately used.

Further, the silane coupling agent layer can also be formed by a vapor deposition method, and specifically, the inorganic substrate is formed by exposing the inorganic substrate to the vapor of the silane coupling agent, that is, the silane coupling agent in a substantially gaseous state. .. The vapor of the silane coupling agent can be obtained by heating the silane coupling agent in a liquid state to a temperature from 40 ° C. to about the boiling point of the silane coupling agent. The boiling point of the silane coupling agent varies depending on the chemical structure, but is generally in the range of 100 to 250 ° C. However, heating at 200 ° C. or higher is not preferable because it may cause a side reaction on the organic group side of the silane coupling agent.
The environment for heating the silane coupling agent may be any of pressure, normal pressure, and reduced pressure, but in the case of promoting vaporization of the silane coupling agent, normal pressure or reduced pressure is preferable. Since many silane coupling agents are flammable liquids, it is preferable to carry out the vaporization work in a closed container, preferably after replacing the inside of the container with an inert gas.
The time for exposing the inorganic substrate to the silane coupling agent is not particularly limited, but is preferably 20 hours or less, more preferably 60 minutes or less, still more preferably 15 minutes or less, and most preferably 1 minute or less.
The temperature of the inorganic substrate during exposure of the inorganic substrate to the silane coupling agent is an appropriate temperature between -50 ° C and 200 ° C depending on the type of the silane coupling agent and the desired thickness of the silane coupling agent layer. It is preferable to control the temperature.

The film thickness of the silane coupling agent layer is extremely thin compared to the inorganic substrate, the easily peelable layer, the polymer film, etc., and is negligible from the viewpoint of mechanical design. In principle. At a minimum, a thickness on the order of a single molecular layer is sufficient. Generally, it is less than 400 nm, preferably 200 nm or less, more preferably 100 nm or less, more preferably 50 nm or less, still more preferably 10 nm or less in practical use. However, in the calculated region of 5 nm or less, the silane coupling agent layer may exist in a cluster shape rather than as a uniform coating film. The film thickness of the silane coupling agent layer can be calculated from the ellipsometry method or the concentration and coating amount of the silane coupling agent solution at the time of coating.

<Manufacturing method of laminated body>
Hereinafter, a method for manufacturing a laminated body according to the present embodiment will be described.
The method for manufacturing a laminated body according to the present embodiment is as follows.
Step A to form a silane coupling agent layer on an inorganic substrate to obtain a first laminate,
Step B to prepare the easily peelable layer and
It has at least a step C of forming the easily peelable layer on the first laminated body.

In the above configuration, the step B is a step of preparing a second laminated body in which the easily peelable layer and the heat-resistant polymer film are laminated.
The step C may be a step of laminating the first laminated body and the second laminated body.

<Process A>
In step A, a silane coupling agent layer is formed on the inorganic substrate to obtain a first laminated body. Since the details of the method of forming the silane coupling agent layer on the inorganic substrate have already been described, the description thereof is omitted here.

<Process B>
In step B, an easily peelable layer is prepared. Since the method of preparing the easily peelable layer as a single substance has already been described, the description thereof is omitted here.
Here, the step B may be a step of preparing a second laminated body in which the easily peelable layer and the heat-resistant polymer film are laminated. As a method for preparing the second laminate, first, an easily peelable layer (polyamic acid film) before imidization is prepared, and then a polyamic acid for forming a polymer film is formed on the easily peelable layer before imidization. The solution is applied and dried to form a polymer film (polyamic acid film) before imidization, and finally, imidization (heat treatment) is performed to make the easily peelable layer before imidization and the height before imidization. A method of imidizing the molecular film together to obtain a second laminated body in which the easily peelable layer and the heat-resistant polymer film are laminated can be mentioned.
Further, as another method, after applying the polyamic acid solution for forming the easily peelable layer on the support, the polyamic acid solution for forming the easily peelable layer is applied on the surface coated with the polyamic acid solution without drying (in the solution state). , A polyamic acid solution for forming a polymer film is applied, and both are dried to make the easily peelable layer before imidization and the polymer film before imidization laminated, and finally imidization (heating). Treatment) to imidize both the easy-release layer before imidization and the polymer film before imidization to obtain a second laminated body in which the easy-release layer and the heat-resistant polymer film are laminated. Can be mentioned.

<Process C>
In step C, the first laminated body and the easily peelable layer are bonded together. The step C may be a step of laminating the first laminated body and the second laminated body. Specifically, the silane coupling agent layer formed on the inorganic substrate and the easily peelable layer or the second laminated body are pressed and bonded as a bonding surface.

The pressurization treatment may be performed, for example, in an atmospheric pressure atmosphere or in a vacuum while heating a press, a laminate, a roll laminate, or the like. In addition, a method of pressurizing and heating in a flexible bag can also be applied. From the viewpoint of improving productivity and reducing the processing cost brought about by high productivity, pressing or roll laminating in an air atmosphere is preferable, and a method using rolls (roll laminating or the like) is particularly preferable.

When pressurization and heating are performed at the same time, the pressure is preferably 1 MPa to 20 MPa, more preferably 3 MPa to 10 MPa. When it is 20 MPa or less, it is possible to suppress damage to the inorganic substrate. Further, when it is 1 MPa or more, it is possible to prevent a portion that does not adhere to each other and insufficient adhesion. The temperature when pressurization and heating are performed at the same time is preferably 80 ° C. to 300 ° C., more preferably 100 ° C. to 250 ° C. When the polymer film is a polyimide film, if the temperature is too high, the polyimide film may be damaged, and if the temperature is too low, the adhesion tends to be weakened. Examples of the process of simultaneously heating and pressurizing include high temperature roll laminating. In this case, since the time for heating and pressurizing the inorganic substrate and the film is short, it is preferable that the temperature is high within the above range. When the pressurization and the heating are performed at the same time, the heating / pressurizing time is preferably 1 to 60 seconds, more preferably 1 to 30 seconds.
Further, the pressurization treatment can be performed in an atmospheric pressure atmosphere as described above, but it is preferable to perform the pressure treatment under vacuum in order to obtain a stable peel strength on the entire surface. At this time, the degree of vacuum is sufficient with the degree of vacuum by a normal oil rotary pump, and about 10 Torr or less is sufficient.
As a device that can be used for pressure treatment, for example, "11FD" manufactured by Imoto Seisakusho can be used for pressing in a vacuum, and a roll-type film laminator in a vacuum or after vacuuming. For vacuum laminating such as a film laminator that applies pressure to the entire surface of the glass at once with a thin rubber film, for example, "MVLP" manufactured by Meiki Seisakusho can be used.

The pressurization process can be performed separately for the pressurization process and the heating process. In this case, only the pressurization process may be performed and the heating process may not be performed. When the pressurizing process is separated into a pressurizing process and a heating process, the polymer film and the inorganic substrate are added at a relatively low temperature (for example, a temperature of less than 120 ° C., more preferably 95 ° C. or lower). It is preferable to secure close contact between the two by applying pressure (preferably about 0.2 to 50 MPa). When the heating process is performed, the heating process is performed at a relatively high temperature (for example, 100 ° C. or higher, more preferably 120 to 250 ° C.) at low pressure (preferably less than 0.2 MPa, more preferably 0.1 MPa or less) or normal pressure. More preferably, it is heated at 150 to 250 ° C.). As a result, the chemical reaction at the close contact interface is promoted, and the polymer film and the inorganic substrate can be laminated. When the pressure treatment and the heat treatment are performed separately, the main purpose of the pressure treatment is to bring the inorganic substrate and the film into close contact with each other. In that case, since it is assumed that a device capable of heating for a long time such as a batch oven is used as the heating step, the heating temperature can be low even when pressurization and heating are performed at the same time. When the pressurizing process and the heating process are performed separately, the heating time is preferably 1 minute to 120 minutes, more preferably 5 minutes to 90 minutes.

From the above, it is possible to obtain a laminated body in which the first laminated body and the easily peelable layer are bonded together, or a laminated body in which the first laminated body and the second laminated body are bonded together. However, the method for producing a laminate according to the present invention is not limited to this example. As another example, after forming the silane coupling agent layer on the inorganic substrate, a polyamic acid solution for forming an easily peelable layer is applied on the silane coupling agent layer, dried, and further, if necessary, high. Examples thereof include a method in which a polyamic acid solution for forming a molecular film is applied, dried, and then imidized to obtain a laminate.

<Manufacturing method of flexible electronic device>
When the laminate is used, an electronic device is formed on the polymer film of the laminate using existing equipment and processes for manufacturing electronic devices, and the polymer film or the easily peelable layer is peeled off from the laminate. Flexible electronic devices can be made.
As used herein, an electronic device is a wiring board having a single-sided, double-sided, or multi-layered structure for electrical wiring, an electronic circuit including active elements such as transistors and diodes, and passive devices such as resistors, capacitors, and inductors, and others. Sensor elements that sense pressure, temperature, light, humidity, etc., biosensor elements, light emitting elements, liquid crystal displays, electrophoretic displays, self-luminous displays and other image display elements, wireless and wired communication elements, arithmetic elements, storage elements, MEMS element, solar cell, thin film, etc.

In the method for manufacturing a device structure in the present specification, a device is formed on a polymer film or an easily peelable layer of a laminate produced by the above-mentioned method, and then the polymer film is peeled off from the inorganic substrate.

The method of peeling the polymer film or the easily peelable layer with the device from the inorganic substrate is not particularly limited, but the method of winding from the end with a tweezers or the like, making a cut in the polymer film, and applying an adhesive tape to one side of the cut portion. A method of winding from the tape portion after sticking, a method of vacuum-adsorbing one side of the cut portion of the polymer film or the easily peelable layer, and then winding from that portion can be adopted. At the time of peeling, if the cut portion of the polymer film or the easily peelable layer is bent with a small curvature, stress is applied to the device at that portion and the device may be destroyed. Therefore, the curvature is as large as possible. It is desirable to peel it off in the state. For example, it is desirable to wind it while winding it on a roll having a large curvature, or to use a machine having a structure in which the roll having a large curvature is located at the peeling portion.
As a method of making a cut in the polymer film or the easily peelable layer, a method of cutting the polymer film or the easily peelable layer with a cutting tool such as a cutting tool, or a polymer film by relatively scanning a laser and a laminate. Alternatively, a method of cutting the easily peelable layer, a method of cutting the polymer film or the easily peelable layer by relatively scanning the water jet and the laminate, or a polymer film or a polymer film while slightly cutting to the glass layer by a semiconductor chip dicing device. There is a method of cutting the easily peelable layer, but the method is not particularly limited. For example, in adopting the above-mentioned method, it is also possible to appropriately adopt a method such as superimposing ultrasonic waves on the cutting tool or adding a reciprocating motion or a vertical motion to improve the cutting performance.
Further, it is also useful to attach another reinforcing base material to the part to be peeled off in advance and peel off the entire reinforcing base material. When the flexible electronic device to be peeled off is the backplane of the display device, it is also possible to attach the front plane of the display device in advance, integrate it on an inorganic substrate, and then peel off both at the same time to obtain a flexible display device. be.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

<Preparation Example 1: Preparation of Polyamic Acid Solution 1>
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 22.73 parts by mass of 4,4'-diaminobenzanilide (DABAN) and 21.1 parts by mass of N, N- Colloidal silica (lubricant) is a dispersion of dimethylacetamide (DMAc) and colloidal silica (lubricant) dispersed in dimethylacetamide ("Snowtex (registered trademark) DMAC-ST-ZL" manufactured by Nissan Chemical Industries, Ltd.). The total amount of polymer solids in the polyamic acid solution was added to 0.4% by mass, and the mixture was completely dissolved. Then, 22.73 parts by mass of 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA) was added separately as a solid, and then stirred at room temperature for 24 hours. Then, 173.1 parts by mass of DMAc was added and diluted to obtain a polyamic acid solution 1 having a solid content (NV) of 12% by mass and a reduction viscosity (ηsp / C) of 3.10 dl / g.

<Preparation Example 2: Preparation of Polyamic Acid Solution 2>
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 11.36 parts by mass of 4,4'-diaminobenzanilide (DABAN) and 11.32 parts by mass of 2,2' -A dispersion consisting of bis (trifluoromethyl) benzidine (TFMB), 21.1 parts by mass of N, N-dimethylacetamide (DMAc), and colloidal silica (lubricant) dispersed in dimethylacetamide (manufactured by Nissan Chemical Industries, Ltd.). "Snowtex (registered trademark) DMAC-ST-ZL") was added so that the total amount of polymer solids in the polyamic acid solution of silica (lubricant) was 0.4% by mass, and the mixture was completely dissolved. Then, 22.73 parts by mass of 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA) was added separately as a solid, and then stirred at room temperature for 24 hours. Then, 173.1 parts by mass of DMAc was added and diluted to obtain a polyamic acid solution 2 having a solid content (NV) of 12% by mass and a reduction viscosity (ηsp / C) of 3.28 dl / g.

<Preparation Example 3: Preparation of Polyamic Acid Solution 3>
A container equipped with a nitrogen introduction tube, a thermometer and a stirring rod was replaced with nitrogen, and then 4,4'-diaminodiphenyl ether (ODA) was added. Next, DMAc was added to completely dissolve it, and then pyrolimetic acid anhydride (PMDA) was added to polymerize ODA and PMDA as monomers in DMAc at a molar ratio of 1/1, and the monomer charging concentration was 15. The mixture was adjusted to be mass% and stirred at 25 ° C. for 5 hours to obtain a brown viscous polyamic acid solution 3. The reduced viscosity (ηsp / C) was 2.1 dl / g.

<Preparation Example 4: Preparation of Polyamic Acid Solution 4>
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 22.72 parts by mass of 2,2'-bis (trifluoromethyl) benzidine (TFMB) and 21.1 parts by mass were added. N, N-dimethylacetamide (DMAc) and a dispersion obtained by dispersing colloidal silica (lubricant) in dimethylacetamide (“Snowtex (registered trademark) DMAC-ST-ZL” manufactured by Nissan Chemical Industries, Ltd.) are used as silica ( Lubricants) were added so that the total amount of polymer solids in the polyamic acid solution was 0.4% by mass, and the mixture was completely dissolved. Then, 22.73 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic acid unihydrate (CBDA) was added in portions and then stirred at room temperature for 24 hours. Then, 173.1 parts by mass of DMAc was added and diluted to obtain a polyamic acid solution 4 having a solid content (NV) of 12% by mass and a reduction viscosity (ηsp / C) of 3.28 dl / g.

<Preparation Example 5: Preparation of Polyimide Solution 1>
While introducing nitrogen gas into a reaction vessel equipped with a nitrogen introduction tube, a Dean Stark tube and a reflux tube, a thermometer, and a stirring rod, 19.86 parts by mass of 4,4'-diaminodiphenyl sulfone (4,4') was introduced. -DDS), 4.97 parts by mass of 3,3'-diaminodiphenyl sulfone (3,3'-DDS) and 80 parts by mass of gamma butyrolactone (GBL) were added. Subsequently, 31.02 parts by mass of 4,4'-oxydiphthalic acid unihydrate (ODPA), 24 parts by mass of GBL, and 13 parts by mass of toluene were added at room temperature, and then the temperature was raised to 160 ° C. The mixture was heated under reflux at 160 ° C. for 1 hour for imidization. After the imidization was completed, the temperature was raised to 180 ° C., and the reaction was continued while extracting toluene. After the reaction for 12 hours, the oil bath was removed and the temperature was returned to room temperature, GBL was added so that the solid content had a concentration of 20% by mass, and a polyimide solution 1 having a reduced viscosity of 0.70 (ηsp / C) dl / g was obtained.

<Manufacturing Example 1: Manufacture of Polyimide Film F1>
The polyamic acid solution 1 was coated on the non-slip material surface of the polyethylene terephthalate film A4100 (support manufactured by Toyobo Co., Ltd.) by adjusting the final film thickness to 15 μm using a comma coater. The polyethylene terephthalate film A4100 passed through a hot air furnace, was wound up, and was dried at 100 ° C. for 10 minutes at this time. After drying, the self-supporting polyamic acid film (green film) is peeled off from the support, passed through a pin tenter having a pin sheet on which pins are arranged, and the film end is gripped by inserting it into the pins, and the film does not break. The pin sheet spacing is adjusted and transported so that unnecessary slack does not occur, and the film is heated at 200 ° C for 3 minutes, 250 ° C for 3 minutes, and 300 ° C for 6 minutes to carry out the imidization reaction. I made it progress. Then, the film was cooled to room temperature in 2 minutes, and the portions of the film having poor flatness were cut off with a slitter and wound into a roll to obtain 500 m of a polyimide film F1 having a width of 450 mm.

<Manufacturing Example 2: Manufacture of Polyimide Film F2>
A polyimide film F2 was obtained in the same manner as in Production Example 1 except that the polyamic acid solution 1 was changed to the polyamic acid solution 2.

<Manufacturing Example 3: Manufacture of Polyimide Film F3>
The polyamic acid solution 1 was coated on the non-slip material surface of the polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd.) by adjusting the final film thickness to 0.5 μm using a comma coater. The polyethylene terephthalate film A4100 passed through the hot air furnace and was wound up, and at this time, it was dried at 100 ° C. for 10 minutes. After winding this, it was set again on the comma coater side, and subsequently, the polyamic acid solution 3 obtained in Production Example 3 was applied onto the dried product of the polyamic acid solution 1 so that the final film thickness was 15 μm. This was dried at 100 ° C. for 10 minutes. After drying, the self-supporting polyamic acid film is peeled off from the support, passed through a pin tenter having a pin sheet on which the pins are arranged, and the film end is gripped by inserting it into the pins so that the film does not break and The pin sheet spacing was adjusted so as not to cause unnecessary slack, and the film was transported, and heated at 200 ° C. for 3 minutes, 250 ° C. for 3 minutes, and 400 ° C. for 6 minutes to proceed the imidization reaction. Then, the film was cooled to room temperature in 2 minutes, and the portions of the film having poor flatness were cut off with a slitter and wound into a roll to obtain 100 m of a polyimide film F3 having a width of 450 mm.

<Manufacturing Example 4: Manufacture of Polyimide Film F4>
A polyimide film F4 was obtained in the same manner as in Production Example 3 except that the polyamic acid solution 1 was changed to the polyamic acid solution 2.

<Manufacturing Example 5: Manufacture of Polyimide Film F5>
The same as in Production Example 3 except that the polyimide solution 1 was used instead of the polyamic acid solution 3 and the heat treatment after gripping with a pin sheet was set to 200 ° C. for 3 minutes, 250 ° C. for 2 minutes, and 320 ° C. for 3 minutes. A polyimide film F5 was obtained in an amount of 100 m.

<Manufacturing Example 6: Manufacture of Polyimide Film F6>
A polyimide film F6 was obtained in the same manner as in Production Example 5 except that the polyamic acid solution 4 was used instead of the polyimide solution 1.

<Manufacturing Example 7: Manufacture of Polyimide Film F7>
The polyamic acid solution 1 obtained in Production Example 1 was applied to the non-slip material surface of the polyethylene terephthalate film A4100 (manufactured by Toyo Spinning Co., Ltd.) using a comma coater so that the final film thickness was 0.5 μm. The polyamic acid solution 3 obtained in Production Example 3 was applied onto the polyamic acid solution 1 with a die coater so that the final film thickness was 15 μm. This was dried at 110 ° C. for 10 minutes. The polyamic acid film that has obtained self-support after drying is peeled off from the A4100 film that has been used as a support, passed through a pin tenter having a pin sheet on which pins are arranged, and the film end is gripped by inserting it into the pins, and the film does not break. The pin sheet spacing is adjusted and transported so that unnecessary slack does not occur, and the film is heated at 200 ° C for 3 minutes, 250 ° C for 3 minutes, and 400 ° C for 6 minutes to carry out the imidization reaction. I made it progress. After that, the film was cooled to room temperature in 2 minutes, and the portions of the film having poor flatness were cut off with a slitter and wound into a roll to obtain 100 m of a polyimide film F7 having a width of 450 mm.

<Manufacturing Example 8: Manufacture of Polyimide Film F8>
A polyimide film F8 was obtained in the same manner as in Production Example 7 except that the polyamic acid solution 2 was used instead of the polyamic acid solution 1.

<Manufacturing Example 9: Manufacture of Polyimide Film F9>
The polyamic acid solution 1 was changed to the polyamic acid solution 3, and the heat treatment after gripping with the pin sheet was the same as in Production Example 1 except that the heat treatment was performed at 200 ° C. for 3 minutes, 250 ° C. for 2 minutes, and 400 ° C. for 3 minutes. A polyimide film F9 was obtained in an amount of 100 m.

<Manufacturing Example 10: Manufacture of Polyimide Film F10>
The polyamic acid solution 1 was changed to the polyimide acid solution 1, and the heat treatment after gripping with the pin sheet was the same as in Production Example 1 except that the heat treatment was performed at 200 ° C. for 3 minutes, 250 ° C. for 2 minutes, and 320 ° C. for 3 minutes. A polyimide film F10 was obtained in an amount of 100 m.

<Manufacturing Example 11: Manufacture of Polyimide Film F11>
A polyimide film F11 was obtained in the same manner as in Production Example 1 except that the polyamic acid solution 1 was changed to the polyamic acid solution 4.

[Preparation of laminated body]
<Examples 1, 2 and Comparative Examples 1, 2, 3>
First, a glass substrate was prepared. The glass substrate is 0.7 mm thick OA10G glass (manufactured by NEG) cut into a size of 100 mm × 100 mm. The glass substrate used was washed with pure water, dried, and then irradiated with a UV / O3 irradiator (SKR1102N- ₀₃ manufactured by LAN Technical) for 1 minute to dry wash.
Next, a silane coupling agent layer was formed on the glass substrate. The method of applying the silane coupling agent to the glass substrate was carried out using the experimental apparatus shown in FIG. FIG. 1 is a schematic view of an experimental device for applying a silane coupling agent to a glass substrate. As shown in FIG. 1, the experimental apparatus includes a processing chamber (chamber) 6 connected to a gas introduction port 2, an exhaust port 8, and a chemical liquid tank (silane coupling agent tank) 3. The chemical liquid tank (silane coupling agent tank) 3 is filled with a silane coupling agent, and the temperature is controlled by a hot water tank (water bath) 4 provided with a heater 5. A gas introduction port 12 is connected to the chemical liquid tank (silane coupling agent tank) 3, and gas can be introduced from the outside. The gas flow rate is adjusted by the flow meter 1 connected to the gas introduction port 12. When the gas is introduced from the gas introduction port 12, the vaporized silane coupling agent in the chemical liquid tank 3 is extruded into the treatment chamber 6, and the silane coupling agent layer is placed on the glass substrate 7 arranged in the treatment chamber 6. Adheres as.
150 g of 3-aminopropyltrimethoxysilane (silane coupling agent Shin-Etsu Chemical KBM903) was placed in a chemical solution tank 3 having a capacity of 1 L, and the outer water bath was warmed to 41 ° C. Then, the steam that came out was sent to the chamber together with clean dry air. The gas flow rate was 25 L / min, the substrate temperature was 23 ° C., and the exposure time of the glass substrate was 5 minutes. The temperature of the clean dry air was 23 ° C. and the humidity was 1.2% RH. Since the exhaust is connected to the negative pressure exhaust port, it is confirmed by the differential pressure gauge that the chamber has a negative pressure of about 10 Pa.
Next, the polyimide film F1 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 1. Similarly, the polyimide film F2 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 2. Further, the polyimide film F9 was laminated on the silane coupling agent layer to obtain a laminate according to Comparative Example 1. Further, the polyimide film F10 was laminated on the silane coupling agent layer to obtain a laminate according to Comparative Example 2. Further, the polyimide film F11 was laminated on the silane coupling agent layer to obtain a laminate according to Comparative Example 3. The size of the polyimide film to be bonded was 70 mm × 70 mm. A laminator manufactured by MCK was used for bonding, and the bonding conditions were compressed air pressure: 0.6 MPa, temperature: 23 ° C., humidity: 55% RH, and laminating speed: 50 mm / sec.
The polyimide film F1 in Example 1 and the polyimide film F2 in Example 2 correspond to the easily peelable layer in the present invention.

<Examples 3 to 8>
The laminates according to Examples 3 to 8 were obtained by the same method as the method for producing the laminates according to Examples 1, 2 and Comparative Examples 1, 2 and 3. In Example 3, the polyimide film F3 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 3. In Example 4, the polyimide film F4 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 4. In Example 5, the polyimide film F5 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 5. Further, in Example 6, the polyimide film F6 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 6. Further, in Example 7, the polyimide film F7 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 7. Further, in Example 8, the polyimide film F8 was bonded onto the silane coupling agent layer to obtain a laminate according to Example 8. The bonding was performed by using a polyimide surface made of a

polyamic acid solution

1 or 2 of a two-layered polyimide film as a bonding surface with a silane coupling agent layer.
In the polyimide film F3 of Example 3, the layer formed from the polyamic acid solution 1 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyamic acid solution 3 corresponds to the polymer film of the present invention. do.
Further, in the polyimide film F4 of Example 4, the layer formed from the polyamic acid solution 2 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyamic acid solution 3 corresponds to the polymer film of the present invention. do.
Further, in the polyimide film F5 of Example 5, the layer formed from the polyamic acid solution 1 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyimide solution 1 corresponds to the polymer film of the present invention. ..
Further, in the polyimide film F6 of Example 6, the layer formed from the polyamic acid solution 1 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyamic acid solution 4 corresponds to the polymer film of the present invention. do.
Further, in the polyimide film F7 of Example 7, the layer formed from the polyamic acid solution 1 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyamic acid solution 3 corresponds to the polymer film of the present invention. do.
Further, in the polyimide film F8 of Example 8, the layer formed from the polyamic acid solution 2 corresponds to the easily peelable layer of the present invention, and the layer formed from the polyamic acid solution 3 corresponds to the polymer film of the present invention. do.

<Measurement of 90 ° initial peel strength>
The laminate obtained by producing the above laminate was heat-treated at 100 ° C. for 10 minutes in an atmospheric atmosphere. Then, the 90 ° initial peel strength between the inorganic substrate (glass substrate or silicon wafer) and the polyimide film was measured. The results are shown in Table 1.
The measurement conditions for the 90 ° initial peel strength are as follows.
Peel the film at a 90 ° angle to the inorganic substrate.
Measure 5 times and use the average value as the measured value.
Measuring device; Shimadzu Autograph AG-IS
Measurement temperature; room temperature (25 ° C)
Peeling speed; 100 mm / min
Atmosphere; Atmosphere measurement sample width; 2.5 cm

<Measurement of 90 ° peel strength after heating at 450 ° C for 1 hour>
The laminate obtained by producing the above laminate was heat-treated at 100 ° C. for 10 minutes under a nitrogen atmosphere. Further, it was heated at 450 ° C. for 1 hour in a nitrogen atmosphere. Then, the 90 ° peel strength between the inorganic substrate and the polyimide film was measured. The results are shown in Table 1. The measurement conditions for the 90 ° peel strength after heating at 450 ° C. for 1 hour were the same as the 90 ° initial peel strength.

1 Flow meter 2 Gas inlet 3 Chemical tank (silane coupling agent tank)
4 Hot water tank (water bath)
5 Heater 6 Processing chamber (chamber)
7 Glass substrate 8 Exhaust port 12 Gas inlet

Claims

An inorganic substrate, a silane coupling agent layer, and an easily peelable layer are provided in this order.
The easily peelable layer is a laminate characterized by having a biphenyltetracarboxylic acid dianhydride and a structural unit derived from diaminobenzanilide.
The laminate according to claim 1, wherein the 90 ° peel strength between the easily peelable layer and the inorganic substrate after heating at 450 ° C. for 1 hour is 0.3 N / cm or less.
The laminate according to claim 1 or 2, wherein the 90 ° initial peel strength between the easily peelable layer and the inorganic substrate is 0.03 N / cm or more.
The laminate according to claim 1, further comprising a heat-resistant polymer film on the easily peelable layer.
The laminate according to claim 4, wherein the 90 ° peel strength between the heat-resistant polymer film and the inorganic substrate after heating at 450 ° C. for 1 hour is 0.3 N / cm or less.
The laminate according to claim 4 or 5, wherein the 90 ° initial peel strength between the heat-resistant polymer film and the inorganic substrate is 0.03 N / cm or more.